Inadequate delivery of nutrition to the critically ill is common, and may adversely affect clinical outcomes, including survival. This thesis reports studies designed to characterise the gastrointestinal dysfunction underlying feed intolerance in the critically ill, as well as the pathophysiology of these dysfunctions, and investigate potential therapeutic measures. While it has been established that enteral nutrition is frequently unsuccessful in the critically ill, assessment of the success of feeding in an Australian intensive care unit (ICU) had not been performed previously. A prospective survey examined the incidence of, and risk factors for, feed intolerance in the ICU at the Royal Adelaide Hospital and demonstrated that, in 40 patients receiving enteral feeding, only about 60% of their nutritional requirements were met at the end of the first week. The main cause for this lack of success was large gastric residual volumes, indicative of delayed gastric emptying (GE). This study, accordingly, quantified the limitations of nutritional delivery in contemporary practice in a local ICU. The results suggest that a better understanding of the pathogenesis underlying this problem is warranted in order to direct research into improved therapies. Scintigraphy is the most accurate technique to measure GE, but is difficult to perform in the ICU. A simpler, more convenient, test would increase the accessibility of GE measurement for both research and clinical purposes. A study comparing a breath test technique and gastric residual volume measurement to the scintigraphic measurement of GE in 25 mechanically ventilated patients demonstrated that GE measured by a breath test technique closely correlated with that measured by scintigraphy. While the breath test had a specificity of 100% it only had a sensitivity of about 60% in the prediction of delayed GE. Similarly, gastric residual volume measurement correlated with scintigraphic measurement of GE but also lacked sensitivity. The breath test has previously been demonstrated to be highly reproducible and it represents a useful option for repeated measurement of GE in the same patient. It is therefore likely to be useful to determine changes in GE over time or in response to a therapeutic intervention. There is a lack of information about the prevalence and determinants of delayed GE in the critically ill. Previous studies have substantial limitations and scintigraphic measurement of GE has only rarely been used. A study comparing GE measured by scintigraphy in 25 patients to 14 healthy subjects demonstrated that GE was delayed in approximately 50% of the ICU patients (>10% retention at 4h) and markedly delayed in about 20% (>50% retention at 4h). Patients with trauma and sepsis appeared to have a relatively higher prevalence of delayed GE (80% and 75% respectively). In addition, the longer the patient had been in ICU the more normal the rate of GE. Quantification of delayed GE may prove useful by defining patients who may benefit from preventative or therapeutic options. The abnormalities in gastrointestinal motility underlying delayed GE in the critically ill are poorly characterised. Simultaneous manometric and gastric emptying measurements were performed in 15 mechanically ventilated patients and 10 healthy subjects. These studies demonstrated that delayed GE was associated with reduced antral activity, increased pyloric activity and increased retrograde duodenal activity in the patients. Persistent fasting motility during feeding was also frequently observed. Furthermore, the feedback response to small intestinal nutrients was enhanced. This latter observation may provide an explanation for the delayed GE and warrants further investigation. Recent studies suggest that the hormone cholecystokinin may be a mediator of increased small intestinal feedback and, if confirmed, this has clear therapeutic implications. Nutrient absorption has rarely been measured in the critically ill. GE and glucose absorption (using 3-O-methyl glucose) were measured simultaneously in 19 ICU patients and compared to 19 healthy subjects. Glucose absorption was shown to be markedly reduced in the patients. Slow GE was associated with delayed, and reduced, absorption. However, glucose absorption was also reduced in patients with normal GE suggesting that reduced glucose absorption in critical illness is only partly due to delayed GE. Accordingly, measures to improve the effectiveness of GE and thereby improve overall nutritional status may be compromised by abnormal small intestinal absorption. The mechanisms underlying this warrant further investigation. A number of therapeutic options directed at improving the delivery of nutrition were examined. In a study involving 20 mechanically ventilated patients, administration of 200mg erythromycin intravenously was shown to be superior to placebo for treating feed intolerance. The optimal dose of erythromycin, however, was unclear. In a subsequent study involving 35 ICU patients, GE was measured using a breath test technique, before and after 2 different doses of erythromycin or placebo and a ‘low’ intravenous dose (70mg) of erythromycin appeared to be as effective as a ‘moderate’ dose (200mg). Both doses were only effective in subjects who had delayed GE at baseline. Based on the outcome of these studies, low doses of erythromycin have subsequently been routinely used to treat feed intolerance in the critically ill patients at the Royal Adelaide Hospital. Animal and human studies suggested that the antibiotic, cefazolin, may have a prokinetic effect. Cefazolin, however, did not demonstrate similar prokinetic activity at a ‘low’ dose (50mg) in a critically ill cohort. The results of this study do not support the use of this agent, at this dose, as a prokinetic, in this population. If nasogastric administration of nutrition proves unsuccessful an alternative is to infuse nutrient directly into the small intestine. However, the placement of feeding tubes distal to the pylorus is technically difficult. A novel technique for postpyloric tube insertion was examined with promising results. In summary, the studies described in this thesis have provided a number of insights relevant to the management of the critically ill by quantifying the prevalence of feed intolerance and delayed GE, characterising some of the disturbances in gastrointestinal motility underlying this problem, and evaluating a number of therapeutic interventions. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1345143 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008

Inadequate delivery of nutrition to the critically ill is common, and may adversely affect clinical outcomes, including survival. This thesis reports studies designed to characterise the gastrointestinal dysfunction underlying feed intolerance in the critically ill, as well as the pathophysiology of these dysfunctions, and investigate potential therapeutic measures. While it has been established that enteral nutrition is frequently unsuccessful in the critically ill, assessment of the success of feeding in an Australian intensive care unit (ICU) had not been performed previously. A prospective survey examined the incidence of, and risk factors for, feed intolerance in the ICU at the Royal Adelaide Hospital and demonstrated that, in 40 patients receiving enteral feeding, only about 60% of their nutritional requirements were met at the end of the first week. The main cause for this lack of success was large gastric residual volumes, indicative of delayed gastric emptying (GE). This study, accordingly, quantified the limitations of nutritional delivery in contemporary practice in a local ICU. The results suggest that a better understanding of the pathogenesis underlying this problem is warranted in order to direct research into improved therapies. Scintigraphy is the most accurate technique to measure GE, but is difficult to perform in the ICU. A simpler, more convenient, test would increase the accessibility of GE measurement for both research and clinical purposes. A study comparing a breath test technique and gastric residual volume measurement to the scintigraphic measurement of GE in 25 mechanically ventilated patients demonstrated that GE measured by a breath test technique closely correlated with that measured by scintigraphy. While the breath test had a specificity of 100% it only had a sensitivity of about 60% in the prediction of delayed GE. Similarly, gastric residual volume measurement correlated with scintigraphic measurement of GE but also lacked sensitivity. The breath test has previously been demonstrated to be highly reproducible and it represents a useful option for repeated measurement of GE in the same patient. It is therefore likely to be useful to determine changes in GE over time or in response to a therapeutic intervention. There is a lack of information about the prevalence and determinants of delayed GE in the critically ill. Previous studies have substantial limitations and scintigraphic measurement of GE has only rarely been used. A study comparing GE measured by scintigraphy in 25 patients to 14 healthy subjects demonstrated that GE was delayed in approximately 50% of the ICU patients (>10% retention at 4h) and markedly delayed in about 20% (>50% retention at 4h). Patients with trauma and sepsis appeared to have a relatively higher prevalence of delayed GE (80% and 75% respectively). In addition, the longer the patient had been in ICU the more normal the rate of GE. Quantification of delayed GE may prove useful by defining patients who may benefit from preventative or therapeutic options. The abnormalities in gastrointestinal motility underlying delayed GE in the critically ill are poorly characterised. Simultaneous manometric and gastric emptying measurements were performed in 15 mechanically ventilated patients and 10 healthy subjects. These studies demonstrated that delayed GE was associated with reduced antral activity, increased pyloric activity and increased retrograde duodenal activity in the patients. Persistent fasting motility during feeding was also frequently observed. Furthermore, the feedback response to small intestinal nutrients was enhanced. This latter observation may provide an explanation for the delayed GE and warrants further investigation. Recent studies suggest that the hormone cholecystokinin may be a mediator of increased small intestinal feedback and, if confirmed, this has clear therapeutic implications. Nutrient absorption has rarely been measured in the critically ill. GE and glucose absorption (using 3-O-methyl glucose) were measured simultaneously in 19 ICU patients and compared to 19 healthy subjects. Glucose absorption was shown to be markedly reduced in the patients. Slow GE was associated with delayed, and reduced, absorption. However, glucose absorption was also reduced in patients with normal GE suggesting that reduced glucose absorption in critical illness is only partly due to delayed GE. Accordingly, measures to improve the effectiveness of GE and thereby improve overall nutritional status may be compromised by abnormal small intestinal absorption. The mechanisms underlying this warrant further investigation. A number of therapeutic options directed at improving the delivery of nutrition were examined. In a study involving 20 mechanically ventilated patients, administration of 200mg erythromycin intravenously was shown to be superior to placebo for treating feed intolerance. The optimal dose of erythromycin, however, was unclear. In a subsequent study involving 35 ICU patients, GE was measured using a breath test technique, before and after 2 different doses of erythromycin or placebo and a ‘low’ intravenous dose (70mg) of erythromycin appeared to be as effective as a ‘moderate’ dose (200mg). Both doses were only effective in subjects who had delayed GE at baseline. Based on the outcome of these studies, low doses of erythromycin have subsequently been routinely used to treat feed intolerance in the critically ill patients at the Royal Adelaide Hospital. Animal and human studies suggested that the antibiotic, cefazolin, may have a prokinetic effect. Cefazolin, however, did not demonstrate similar prokinetic activity at a ‘low’ dose (50mg) in a critically ill cohort. The results of this study do not support the use of this agent, at this dose, as a prokinetic, in this population. If nasogastric administration of nutrition proves unsuccessful an alternative is to infuse nutrient directly into the small intestine. However, the placement of feeding tubes distal to the pylorus is technically difficult. A novel technique for postpyloric tube insertion was examined with promising results. In summary, the studies described in this thesis have provided a number of insights relevant to the management of the critically ill by quantifying the prevalence of feed intolerance and delayed GE, characterising some of the disturbances in gastrointestinal motility underlying this problem, and evaluating a number of therapeutic interventions. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1345143 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este estudo trata da recontextualização educacional das Tecnologias da Informação e da Comunicação (TIC) no Programa Ginásio Experimental Carioca (GEC), da Secretaria Municipal de Educação do Rio de Janeiro. Parte de hipótese de trabalho de que, no escopo do referido Programa, as TIC tendem a ser incorporadas como estratégia de substituição tecnológica, remetendo ao esvaziamento do trabalho docente. Para desenvolvê-la, empreende estudo de caso etnográfico e uma análise crítica dos discursos dos sujeitos envolvidos: a observação das práticas no contexto específico e as reflexões dos sujeitos sobre estas mesmas práticas. Elegendo a figura do professor polivalente como chave para a compreensão das relações entre trabalho docente e utilização intensiva das TIC, discute as ressignificações e relexicalizações em circulação. Considerando a extinção do Programa em tela, aborda os desdobramentos que têm sustentado a confirmação da hipótese de esvaziamento do trabalho docente, expresso pela ampliação e pelo aprofundamento desse novo lugar de professor no contexto do Projeto o 6 Ano Experimental / This study introduces the educational recontextualization of Information and Communication Technologies (ICT) in Ginásio Experimental Carioca Program (GEC), of the Municipal Department of Education in Rio de Janeiro. Assume that the working hypothesis that, the scope of that Program, ICT tend to be incorporated as technological substitution strategy, referring to the emptying of teaching work. To develop it, was undertaken an ethnographic case study and a critical analysis of the individuals involved: the observation of practices in a particular context and the reflections of the individuals on these same practices. Electing the figure of multipurpose teacher as a key to understand the relationship between teaching work and intensive use of ICT, argues the ressignifications and relexicalizations in circulation. Considering the Program extinction, discusses the developments that have sustained the confirmation of emptying hypothesis of teaching work, expressed the expansion and deepening of this new teacher place in the context of the 6th grade in Elementary School

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este estudo trata da recontextualização educacional das Tecnologias da Informação e da Comunicação (TIC) no Programa Ginásio Experimental Carioca (GEC), da Secretaria Municipal de Educação do Rio de Janeiro. Parte de hipótese de trabalho de que, no escopo do referido Programa, as TIC tendem a ser incorporadas como estratégia de substituição tecnológica, remetendo ao esvaziamento do trabalho docente. Para desenvolvê-la, empreende estudo de caso etnográfico e uma análise crítica dos discursos dos sujeitos envolvidos: a observação das práticas no contexto específico e as reflexões dos sujeitos sobre estas mesmas práticas. Elegendo a figura do professor polivalente como chave para a compreensão das relações entre trabalho docente e utilização intensiva das TIC, discute as ressignificações e relexicalizações em circulação. Considerando a extinção do Programa em tela, aborda os desdobramentos que têm sustentado a confirmação da hipótese de esvaziamento do trabalho docente, expresso pela ampliação e pelo aprofundamento desse novo lugar de professor no contexto do Projeto o 6 Ano Experimental / This study introduces the educational recontextualization of Information and Communication Technologies (ICT) in Ginásio Experimental Carioca Program (GEC), of the Municipal Department of Education in Rio de Janeiro. Assume that the working hypothesis that, the scope of that Program, ICT tend to be incorporated as technological substitution strategy, referring to the emptying of teaching work. To develop it, was undertaken an ethnographic case study and a critical analysis of the individuals involved: the observation of practices in a particular context and the reflections of the individuals on these same practices. Electing the figure of multipurpose teacher as a key to understand the relationship between teaching work and intensive use of ICT, argues the ressignifications and relexicalizations in circulation. Considering the Program extinction, discusses the developments that have sustained the confirmation of emptying hypothesis of teaching work, expressed the expansion and deepening of this new teacher place in the context of the 6th grade in Elementary School

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Estudamos o efeito do citrato de sildenafil (ViagraÂ), vasodilatador largamente utilizado na terapÃutica da disfunÃÃo erÃtil, sobre o comportamento motor do trato gastrintestinal (TGI) de ratos Wistar. Para tanto, utilizamos 175 animais machos, pesando entre 200 a 350g, distribuÃdos nos quatro seguintes grupos de estudo: efeitos do citrato de sildenafil sobre o i) esvaziamento gÃstrico (EG) e os trÃnsitos gastrintestinal (GI) e ii) intestinal de lÃquido em ratos acordados; iii) a complacÃncia gÃstrica de ratos anestesiados e iv) a contratilidade de tiras isoladas do duodeno de ratos ex vivo. i) Avaliamos, em 64 ratos acordados sob jejum e livre acesso à Ãgua por 24h, o efeito da injeÃÃo (0,2mL; e.v.) de sildenafil (4mg/Kg) ou veÃculo (HCl 0,01N) sobre o EG e o trÃnsito GI de lÃquido, bem como sobre a pressÃo arterial (PA). Mediante gavagem, 1,5mL da refeiÃÃo-teste (vermelho de fenol - 0,5mg/mL em glicose a 5%) foi injetada no estÃmago. Depois de 10, 20 ou 30min, sacrificamos os animais e, apÃs laparotomia, obstruÃmos o piloro, o cÃrdia e o Ãleo terminal. Removemos e dividimos o TGI em: estÃmago e segmentos consecutivos do intestino delgado (40% iniciais; 30% mediais e 30% terminais). ApÃs o processamento destas porÃÃes viscerais, determinamos as absorbÃncias das amostras a 560nm. A retenÃÃo fracional de vermelho fenol em cada segmento permitiu o cÃlculo do EG e trÃnsito GI. Em um grupo separado de animais, a PA foi monitorada continuamente por meio de um sistema digital de aquisiÃÃo de dados durante 20min antes e 30min apÃs o tratamento com sildenafil ou diluente. Comparado ao grupo controle, houve aumento significativo da retenÃÃo gÃstrica (44,2Â2,0 vs 53,2Â2,1; 25,4Â1,3 vs 37,3Â1,6; 20,9Â2,5 vs 32,5Â2,9%) nos animais tratados com sildenafil e sacrificados aos 10, 20, ou 30min, respectivamente, bem como retarde significativo no trÃnsito GI. Embora o sildenafil tenha provocado hipotensÃo, a PA retoma nÃveis basais logo apÃs 10min. O prÃ-tratamento com omeprazol (bloqueador da secreÃÃo Ãcida estomacal) nÃo modificou o efeito do sildenafil sobre os valores de retenÃÃo gÃstrica e intestinal nem nos nÃveis de PA. ii) Noutros animais (n=44), sob jejum de 24h e dotados previamente (3d) de uma cÃnula crÃnica no bulbo duodenal, estudamos o efeito do sildenafil sobre a progressÃo ao longo do intestino delgado de uma refeiÃÃo teste (10MBq de TecnÃcio ligado a fitato e diluÃdo em 1mL de salina 0,9%). Decorridos 20, 30 ou 40min da injeÃÃo (0,2mL e.v.) de sildenafil (4mg/Kg) ou diluente (HCL 0,01N), sacrificamos os animais e, apÃs laparotomia e remoÃÃo do TGI, dividimo-o em: estÃmago, cinco segmentos congruentes e consecutivos de intestino delgado e o intestino grosso. A contagem da radiatividade foi determinada num colimador de gama-cÃmara. O sildenafil promoveu retarde (p<0,05) do TI, indicado pelos retardes dos centros geomÃtricos da refeiÃÃo de 2,8&#61617; 0,2 vs 3,3&#61617; 0,1; 3,0&#61617; 0,2 vs 3,7&#61617; 0,1 e 3,4&#61617; 0,1 vs 4,2&#61617; 0,2 em relaÃÃo ao grupo controle, aos 20, 30 ou 40min. iii) Os estudos de complacÃncia gÃstrica foram conduzidos em 39 ratos anestesiados, sob jejum de 24h. As variaÃÃes do volume gÃstrico (VG), foram medidas por pletismografia, enquanto a PA foi monitorada continuamente por um sistema digital de aquisiÃÃo de dados. Em relaÃÃo aos valores basais (2,91Â0,19mL) o sildenafil (3mg/Kg â e.v.) aumentou (p<0,05) o VG apÃs 10, 20 e 30min (3,08Â0,18; 3,10Â0,17 e 3,09Â0,17mL). A PA basal (105,8Â2,28mmHg) caiu significativamente com o sildenafil (59,8Â3,2; 64,8Â3,7 e 59,3Â4,6mmHg) enquanto o diluente (HCl 0,01N) nÃo modificou seja o VG ou a PA. O prÃ-tratamento mediante esplancnotomia ou injeÃÃo e.v. com azul de metileno (3mg/Kg-bloqueador da guanilato ciclase), L-NNA (3mg/Kg-bloqueador da NO sintetase) ou propranolol (2mg/Kg-Ã-bloqueador) preveniram o aumento do VG pelo sildenafil; jà o pÃs-tratamento com nitroprussiato de sÃdio (1mg/Kg - e.v.) o ampliou significativamente. iv) Avaliamos ainda o efeito do sildenafil sobre a contratilidade de tiras isoladas do duodeno de ratos ex vivo (n=28), sacrificados por deslocamento cervical. Tiras dissecadas do duodeno foram suspensas longitudinalmente em cuba de vidro (10mL), plena de soluÃÃo de Tyrode (37oC e pH 7,4), e submetidas a uma tensÃo inicial de 1g. ApÃs 1h de estabilizaÃÃo, a contratilidade espontÃnea ou induzida das tiras foi registrada continuamente por um sistema digital de aquisiÃÃo de dados. O sildenafil em doses crescentes e cumulativas (0,1 a 300Âmol/L) relaxou (EC50 de 9,6Âmol/L) o duodeno, mais atà que o zaprinaste ou a papaverina (bloqueadores de FDEs) (EC50 91,6 e 78,5Âmol/L, nesta ordem). Observamos ademais que o sildenafil inibiu as contraÃÃes induzidas por acetilcolina ou carbacol (IC50 26,7 e 16,2Âmol/L, respectivamente). Jà o prÃ-tratamento com azul de metileno, ODQ (bloqueador da guanilato ciclase) ou L-NAME (bloquedor da NO sintetase), mas nÃo o D-NAME (isÃmero inativo da NO sintetase) preveniram o efeito do sildenafil. O efeito mio-relaxante do sildenafil foi ampliado pela L-arginina (substrato do NO sintetase) ou nitroprussiato de sÃdio (doador de NO). O prÃ-tratamento com forskolina (estimulador da adenilato ciclase) tambÃm aumentou o efeito mio-relaxante do sildenafil. Em resumo, observamos que o sildenafil diminui a motilidade gastrintestinal, retardando o EG, os trÃnsitos GI e intestinal de lÃquido em ratos acordados; aumenta a complacÃncia gÃstrica em ratos anestesiados alÃm de apresentar efeitos antiespasmÃdico e mio-relaxante sobre tiras isoladas de duodeno de ratos ex vivo; por estimulaÃÃo do sistema nervoso simpÃtico e tendo como provÃvel mecanismo de aÃÃo ao nÃvel do miÃcito gastrintestinal a via do NO/GMP cÃclico. / We evaluated the effect of sildenafil citrate (ViagraÂ) a vasodilator largely used for the treatment of male erectile dysfunction, on the gastrointestinal motility in rats. Experiments were performed on 175 male, Wistar rats, weighing 200-350g. Four groups of study were done: the sildenafil effects on the: i) Gastric emptying (GE) and gastrointestinal (GI) transit and ii) Intestinal transit (IT) of liquid in awake rats; iii) Gastric compliance in anesthetized rats and iv) Contractility of rat duodenal isolated strips. i) In 64 rats fasted for 24h with previous vascular access (right jugular vein and left carotid artery), we studied the effect of an i.v. injection (0.2mL) of sildenafil (4mg/Kg) or vehicle (0.01N HCl) on GE and GI transit of a liquid meal, as well as on arterial pressure (AP) in a separated group of rats. Animals were gavage-fed with 1.5mL of a test meal (0.5mg/mL of phenol red in 5% glucose). After 10, 20 or 30min, animals were sacrificed and submitted to a laparotomy to obstruct the pylorus, cardia and terminal ileus. The gut was removed and then divided into: stomach and consecutive three small intestine segments (40% proximal; 30% medial and 30% terminal). After processing these segments, the dye retention was determined at 560nm. The percentage of dye retention in each segment permitted to evaluate GE and GI transit. Arterial pressure was continuously monitored by a digital acquisition system during 20min before and 30min after sildenafil injection. We observed a significant increase of gastric retention in sildenafil treated rats at 10, 20, or 30min after the test meal (44,2Â2,0 vs 53,2Â2,1; 25,4Â1,3 vs 37,3Â1,6; 20,9Â2,5 vs 32,5Â2,9%, respectively), as well as a significant GI transit delay. Despite of sildenafil inducing hypotension, AP returned to basal levels 10min afterwards. Acid gastic secretion blocking pre-treatment with omeprazol did not modify the sildenafil effect on gastric retention, GI transit or AP. ii) In another group we evaluated the sildenafil (4mg/Kg) or diluente (0.01N HCl, 0.2mL) effects on the IT in awake rats, fasted for 24h. Animals were studied 3d after the insertion of a silastic cannula (0.6cm ID) into the duodenal bulb. We evaluated the progression of a radioactive liquid test meal fed (10MBq of 99mTc â 1mL of saline 0,9%) administered through the inserted cannula into the small intestine. After 20, 30 or 40min, animals were sacrificed by anesthetic overdose. After laparotomy, we removed and divided the gut in: stomach, five congruent and consecutive segments of the small intestine and the large intestine. Radioactivity counting was obtained in a gamma-chamber collimator. Sildenafil promoted an IT delay (p<0.05), indicated by shifting the center of mass to the proximal portions of the TGI (2.8Â0.2 vs 3.3Â0.1; 3.0Â0.2 vs 3.7Â0.1 and 3.4Â0.1 vs 4.2Â0.2) in relation to control group. iii) Gastric compliance study was performed on 39 anesthetized rats after 24h of fasting. Gastric volume (GV) variations were measured by plethysmography while AP was continuously monitored. We have also observed that GV increased (p<0.05) after sildenafil treatment (3mg/Kg - e.v) (3.08Â0.18; 3.10Â0.17 and 3.09Â0.17mL vs 2.91Â0.19mL) at 10, 20 and 30min after drug administation, respectively. Basal AP (105.8Â2.28mmHg) dropped by the sildenafil injection (59.8Â3.2; 64.8Â3.7 and 59.3Â4.6mmHg-p<0.05) while vehicule (0.01N HCl) did not change either GV or AP. After splanchnotomy or pre-treatments (e.v.) with methylene blue (3mg/Kg-guanilate cyclase blocker), L-NNA (3mg/Kg - NO synthase blocker) or propranolol (2mg/Kg - Ã-blocker) prevented GV increase due to sildenafil; while post-treatment with sodium nitroprusside (1mg/Kg - NO donor) raised it. iv) The in vitro contractility studies were performed on isolated duodenal strips obtained from rats (n=28) killed by cervical dislocation. Duodenal strips were suspended longitudinally in a glass chamber (10mL), filled with Tyrode solution (37oC and pH 7.4). After 1h of stabilization under 1g of initial tension, the spontaneous or induced contractility were continuously recorded by a digital acquisition system. Increasing and cummulative doses of sildenafil (0.1 to 300Âmol/L) relaxed (9.6Âmol/L of EC50) the duodenal strips. This effect was more intense than those displayed by zaprinast or papaverine (PDEs blockers) (91.6 and 78.5Âmol/L of EC50, in this order). Sildenafil showed significant antispasmodic and myorelaxant effects on the duodenal contractions induced by acetylcholine or carbamylcholine (IC50 26.7 and 16.2Âmol/L, respectively). Pre-treatment with methylene blue, ODQ (guanilato cyclase blocker) or L-NAME (NO synthase blocker) also prevented these sildenafil effects, but D-NAME (an inactive substrate for NO synthase) did not. Myorelaxant sildenafil effect was reverted by L-arginine (substrate for NO synthase) and contrarily it was largely increased by sodium nitroprusside. Forskolin adenylate cyclase activation pre-treatment also increased the myorelaxant effect of sildenafil. In summary, we have observed that sildenafil slowed down the gastrointestinal motility, delaying GE, GI and intestinal transits of a liquid meal in awake rats; Gastric compliance was also increased in anesthetized rats treated with sildenafil. Sildenafil also exhibited both antispasmodic and myorelaxant effects on isolated strips of duodenum of ex vivo rats. Besides central or peripheral sympathetic nervous system activation, sildenafil possibly acts at the gastrointestinal myocite level by activating the NO/GMPc system.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The monoterpenes &#945;- and &#946;-pinene are constituents commonly found in several essential oils obtained from plants in Brazilian northeast such as âmalva-santaâ and âeucaliptoâ, which are used in folk medicine to treat respiratory and gastrointestinal dysfunctions. Myorelaxant actions are due to the presence of these constituents in their essential oils. The present work aimed to further study the pharmacological effects of these compounds on smooth muscle gastrointestinal contractility as well as on liquid gastric emptying in rats. Wistar rats (200-250 g) were used, sacrificed by cervical dislocation. Strips were carefully obtained from gastric fundus, duodenum and ileum, and were maintained in Tyrodeâs solution. Isometric contractions were recorded through force transducers coupled to a computerized data acquisition system. Solutions containing &#945;- or &#946;-pinene were prepared with Tween 80 (final concentration &#8804; 0,2% v/v). Solely used, &#945;- or &#946;-pinene decreased duodenal basal tonus with IC50 value corresponding to 655.1 ÂM and 810.2 ÂM, respectively. Submaximal contractions induced by K+ (60 mM, K60) or acetylcholine (ACh, 3 ÂM) were inhibited, in a concentration-dependent manner (p < 0.001, ANOVA), with IC50 values of 790.0 [580.2-1007.4] e 760.0 [650.6-870.8] ÂM, respectively to &#945;-pinene and 770.1 [500.3-1180.5] e 620.7 [520.9-750.2] ÂM, respectively to &#946;-pinene. In tissues pre-treated with &#945;- (1 mM) or &#946;-pinene (1 mM) in medium without Ca2+ with EGTA (0.2 mM), ACh (3 ÂM)-induced phasic contractions were inhibited from 18.4  3.3% to 7.7  1.5% and 5.0  1.2% of K60, respectively. In tissues maintained under Ca2+-free conditions (in medium containing EGTA 0.2 mM) and in presence of K+ (60 mM) or ACh (3 ÂM), tonic contractions induced by Ca2+ addition were reduced from 50.2  3.3% and 53.9  5.2%, respectively to values corresponding to 10.6  2.6 % and 24.4  4.1 % to experiments with &#945;-pinene and 6.6  1.1 % and 10.9  3.5 % to experiments with &#946;-pinene, respectively. In tissues pre-treated with &#945;- (1 mM) or &#946;-pinene (1 mM), ACh (60 ÂM)-induced tonic contractions, in verapamil (3 ÂM)-containing medium, were inhibited from 29.0  4.1 % to 10.6  2.7 % and 12.5  2.2 % of the K60, respectively. The caffeine (20 mM)-induced contractile response in normal Tyrodeâs solution was potentiated from 47.8  3.2 % to 72.1  9.0 and 88.8  10.6 % of the control response in virtue of &#945;- (1 mM) or &#946;-pinene (1 mM) presence, respectively. In EGTA-containing Ca2+-free medium, the contractile response to caffeine was reduced to 9.5  3.5%. Under these conditions, and in presence of &#945;- (1 mM) or &#946;-pinene (1 mM), this response was not significantly altered, with values corresponding to 7.2  2.2 e 4.7  1.3 %, respectively. In verapamil- and EGTA-containing Ca2+-free medium, after depletion of the intracellular Ca2+ stores by CCh (100 ÂM), the contractions induced by Ca2+ addition were potentiated by the presence of &#945;- (1 mM) or &#946;-pinene (1 mM) from 30.7  2.1 % to 80.6  4.7 and 51.3  7.6 %, respectively (p < 0.05, Bonferroniâs test). In gastrointestinal dye fractional retention studies, &#945;- or &#946;-pinene increased the rat liquid gastric emptying. On the other hand, they did not alter the ACh-induced contractions on gastric fundus strips. Our study firstly shows that, both &#945;- and &#946;-pinene have prokinetic properties in rats. In isolated tissues, they did not affect cholinergic contractions on gastric fundus strips, but are myorelaxant compounds on rat duodenal preparations, probably by an interference with cellular mechanisms mediated by IP3 release. Moreover, &#945;- and &#946;-pinene activate capacitative Ca2+ entry to intracellular milieu after Ca2+ stores depletion / &#945;- e &#946;-pineno sÃo monoterpenos constituintes do Ãleo essencial de plantas encontradas no Nordeste do Brasil como a malva-santa e o eucalipto que, na medicina popular, sÃo usadas no tratamento de distÃrbios intestinais e respiratÃrios. As aÃÃes miorrelaxantes desses Ãleos essenciais sÃo atribuÃdas à presenÃa de &#945;- e de &#946;-pineno. Nosso objetivo foi estudar mais detalhadamente os efeitos desses constituintes sobre a contratilidade do mÃsculo liso gastrintestinal e sobre o esvaziamento gÃstrico de lÃquido em ratos. No presente estudo, foram usados ratos Wistar machos (200-250g) sacrificados por deslocamento cervical. Tiras de duodeno, Ãleo e fundo de estÃmago foram cortados e mantidos em Tyrode. As contraÃÃes isomÃtricas foram registradas atravÃs de transdutores de forÃa conectados a sistema computadorizado. SoluÃÃes contendo &#945;- ou &#946;-pineno foram preparadas em Tween 80 (concentraÃÃo final &#8804; 0,2% v/v). Usados isoladamente, &#945;- e &#946;-pineno diminuÃram o tÃnus basal em duodeno com CI50 de 655,1 e 810,2 ÂM, respectivamente. ContraÃÃes submaximais induzidas por K+ (60 mM, K60) ou acetilcolina (ACh, 3 ÂM) foram inibidas, de maneira concentraÃÃo-dependente (p < 0,001, ANOVA), com valores de CI50 correspondentes a 790,0 [580,2-1007,4] e 760,0 [650,6-870,8] ÂM, respectivamente, para o &#945;-pineno e 770,1 [500,3-1180,5] e 620,7 [520,9-750,2] ÂM para o &#946;-pineno, respectivamente. Em preparaÃÃes prÃ-tratadas com 1 mM de &#945;- ou &#946;-pineno, a contraÃÃo fÃsica induzida por ACh (3 ÂM) em meio sem Ca2+ contendo EGTA (0,2 mM) foi reduzida de 18,4  3,3 % para 7,7  1,5 % e 5,0  1,2 % da contraÃÃo K60, respectivamente. A contraÃÃo tÃnica induzida por adiÃÃo de Ca2+ (2 mM) em preparaÃÃes mantidas na presenÃa de K+ (60 mM) ou ACh (3 ÂM), em meio sem Ca2+ contendo EGTA (0,2 mM), foi reduzida de 50,2  3,3 % e de 53,9  5,2 % para 10,6  2,6 % e 24,4  4,1 % pelo &#945;-pineno e 6,6  1,1 % e 10,9  3,5 % pelo &#946;-pineno, respectivamente. Em preparaÃÃes prÃ-tratadas com 1 mM de &#945;- ou &#946;-pineno, a contraÃÃo tÃnica induzida por ACh (60 ÂM) em Tyrode normal contendo verapamil (3 ÂM) foi reduzida de 29,0  4,1 % para 10,6  2,7 % e 12,5  2,2 % da K60, respectivamente. A resposta contrÃtil induzida pela cafeÃna (20 mM) em Tyrode normal foi potencializada de 47,8  3,2 % para 72,1  9,0 e 88,8  10,6 % da resposta controle pelo prÃ-tratamento da preparaÃÃo com &#945;- ou &#946;-pineno, respectivamente. Em meio sem Ca2+ com EGTA, a resposta contrÃtil da cafeÃna (20 mM) foi reduzida para 9,5  3,5 %. Sob essa condiÃÃo e, na presenÃa de &#945;- ou &#946;-pineno, a resposta nÃo foi alterada significativamente, correspondendo a 7,2  2,2 e 4,7  1,3 %, respectivamente. ApÃs esgotamento dos estoques intracelulares com CCh (100 mM), a contraÃÃo induzida por adiÃÃo de Ca2+ (2 mM), em meio sem Ca2+ com EGTA (0,2 mM) e verapamil (3 ÂM), foi potencializada pela adiÃÃo prÃvia de &#945;- ou &#946;-pineno de 30,7  2,1 % para 80,6  4,7 e 51,3  7,6 %, respectivamente (p < 0,05, teste de Bonferroni). Em estudos de retenÃÃo fracional de corante no trato gastrintestinal, o &#945;- e o &#946;-pineno aumentaram o esvaziamento gÃstrico, porÃm, a contratilidade induzida por ACh (3 ÂM) em tiras de fundo de estÃmago in vitro nÃo foi alterada pela presenÃa prÃvia de &#945;- e &#946;-pineno. O presente trabalho demonstra, pela primeira vez, que os monoterpenos &#945;- e &#946;-pineno apresentam efeito procinÃtico em ratos. Em tecidos isolados, nÃo afetam a contraÃÃo colinÃrgica em tiras de estÃmago, mas apresentam atividade miorrelaxante em tecido duodenal, por provÃvel interferÃncia com os mecanismos celulares mediados pela formaÃÃo de IP3. AlÃm disso, como demonstrado em Ãleo de rato, esses monoterpenos provavelmente ativam as vias de entrada de Ca2+ para a cÃlula em situaÃÃes de depleÃÃo dos estoques intracelulares

Orientadores: Maria Aparecida Mesquita, Elizabeth João Pavin / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T12:16:52Z (GMT). No. of bitstreams: 1 Cunha_MarizaFaria_D.pdf: 3547651 bytes, checksum: e7cc833c52849656bf197cafac84bfeb (MD5) Previous issue date: 2013 / Resumo: Os objetivos deste estudo foram investigar a motilidade gastrintestinal e a sensibilidade gástrica em pacientes com diabetes mellitus tipo 1 (DM1), e as relações desses fatores com sintomas gastrintestinais, infecção pelo Helicobacter pylori, controle glicêmico, e características psicológicas e nutricionais desses pacientes. Foram estudados 33 pacientes com DM1 com idade média de 39 ± 9 anos, sendo 26 do sexo feminino e 7 do sexo masculino. O tempo desde o diagnóstico do diabetes era de 23±7 anos. Um questionário padronizado foi usado para obter informações sobre dados sóciodemográficos e presença de sintomas gastrintestinais. Foram também registrados os dados laboratoriais e os dados referentes às complicações do diabetes, incluindo a neuropatia periférica. O controle glicêmico foi avaliado de acordo com os valores da hemoglobina glicada (HbA1c). A avaliação nutricional foi realizada através de antropometria e inquéritos alimentares (registro alimentar de 3 dias e questionário de frequência alimentar). A presença de ansiedade e depressão foi avaliada pela Escala Hospitalar de Ansiedade e Depressão (HAD). Os pacientes foram submetidos ao exame de endoscopia digestiva alta, com biópsias gástricas para a pesquisa do Helicobacter pylori e biópsias duodenais para a pesquisa de doença celíaca. O esvaziamento gástrico e a distribuição intragástrica de uma refeição sólida foram avaliados pela cintilografia gástrica. O estudo do tempo de trânsito orocecal (TTOC) foi realizado pelo teste do H2 expirado com lactulose. A sensibilidade gástrica foi avaliada pelo teste de saciedade com água. Nossos resultados mostraram a presença de sintomas gastrintestinais em 75,7% dos pacientes, ansiedade e/ou depressão em 61,3% e infecção pelo H. pylori em 34,4%. Houve uma associação estatisticamente significativa entre sintomas gastrintestinais e ansiedade e/ou depressão. O valor médio da HbA1c foi 9,1±1,7%, indicando controle glicêmico inadequado no grupo estudado. A avaliação dos dados do IMC mostrou que 43,3% dos pacientes estava com sobrepeso e 3,3% eram obesos. Por outro lado, a avaliação dos outros parâmetros antropométricos mostrou que 15% dos pacientes apresentavam-se desnutridos ou com risco nutricional. Além disso, foi observado que a dieta de muitos pacientes era deficitária em termos de consumo calórico e de vitaminas e sais minerais. Entre os pacientes com DM1, 37,9% apresentaram esvaziamento gástrico lento e 30,8% prolongamento do TTOC. Não houve correlação entre os valores do TTOC e do T½ do esvaziamento gástrico. A análise da distribuição intragástrica demonstrou que o esvaziamento gástrico lento estava relacionado com uma maior retenção do conteúdo gástrico no compartimento proximal. Não houve diferença entre os pacientes com DM1 e o grupo-controle quanto aos parâmetros avaliados no teste da saciedade com água. Entretanto, dentro do grupo de pacientes diabéticos, aqueles que apresentavam esvaziamento gástrico mais prolongado ou maiores valores nos escores de ansiedade/depressão apresentaram aumento na sensibilidade gástrica em relação aos outros pacientes do grupo. A ansiedade e depressão ainda estavam relacionadas com a presença de sintomas gastrintestinais, pior controle glicêmico e diminuição da ingestão calórica. Não houve relação entre ansiedade/depressão e alterações no esvaziamento gástrico ou no TTOC. Nenhum dos parâmetros avaliados estava associado com a infecção pelo H. pylori ou com a presença de neuropatia periférica. Nesse estudo também não houve evidência de associação do esvaziamento gástrico lento com a presença de sintomas gastrintestinais, controle glicêmico, consumo energético ou parâmetros nutricionais. Por outro lado, os valores de todos os parâmetros antropométricos estavam significativamente diminuídos nos pacientes com TTOC prolongado, indicando que essa anormalidade afeta negativamente o estado nutricional dos pacientes com DM1. Em conclusão, os resultados desse estudo demonstraram uma interação complexa entre sintomas gastrintestinais, controle glicêmico, alterações motoras e sensoriais, fatores psicológicos e fatores nutricionais em pacientes com DM1, com destaque para a presença de ansiedade e depressão como ligação entre vários desses parâmetros. Nossos dados também reforçam a necessidade de uma abordagem mais abrangente e efetiva dos aspectos psicológicos e nutricionais nesses pacientes / Abstract: The aim of this study was to assess gastrointestinal motility and gastric sensitivity in long-standing type 1 diabetes mellitus (DM1) patients, and the relationships of these factors with gastrointestinal symptoms, Helicobacter pylori infection, glycemic control, and psychological and nutritional features. Thirty-three type 1 DM patients, mean age of 39 ± 9 years, 26 females and 7 males, were included. Diabetes duration was 23±7 years. A standardized questionnaire was used to obtain information about sociodemographic data and chronic GI symptoms. Laboratory data and parameters related to DM complications, including peripheral neuropathy, were recorded. Glycemic control was assessed by glycated hemoglobin (HbA1c). Nutritional evaluation was performed by the assessment of anthropometric indices and from the data of the three-day food diary and food frequency questionnaire. The presence of anxiety and depression was assessed by the Hospital Anxiety and Depression scale. During endoscopy gastric and duodenal biopsies were taken for the assessment of H. pylori infection and celiac disease. Gastric emptying and intragastric distribution of a solid meal were evaluated by scintigraphy. The lactulose hydrogen breath test was used to determine OCTT. Gastric sensitivity was assessed by the water load test. Our results im DM1 showed gastrointestinal symptoms in 75.7%, H. pylori infection in 34.4% and anxiety and/or depression in 61.3%. There was a statistically significant association between gastrointestinal symptoms and anxiety/depression. Mean HbA1c was 9.1±1.7%, indicating poor glycemic control in our study group. According to BMI, 44.6% of DM1 were overweight or obese. On the other hand, the analysis of the other anthropometric parameters showed malnutrition or risk of malnutrition in 15% of DM1. In addition, many patients have diets deficient in calories, vitamins, and minerals. Delayed gastric emptying was found in 37.9% and prolonged OCTT in 30.8% of patients. No significant correlation was found between OCTT and T½ values. Intragastric distribution analysis showed that delayed gastric emptying was related to increased proximal retention of the meal. The assessment of gastric sensitivity by the water load test showed no difference between type 1 DM patients and controls. However, within the patients group increased gastric sensitivity was associated with delayed gastric emptying and also with anxiety/depression. Anxiety and depression were also linked to gastrointestinal symptoms, poorer glycemic control and reduced caloric intake. There was no evidence of a relationship between anxiety/depression and delayed gastric emptying or prolonged OCTT.None of the above parameters were related to H. pylori infection or peripheral neuropathy. We found no evidence of association between delayed gastric emptying and gastrointestinal symptoms, glycemic control, caloric intake or nutritional parameters. In contrast, the values of all anthropometric parameters measured in the present study were significantly decreased in patients with prolonged OCTT, indicating that this abnormality may have a negative effect on nutritional status in type 1 DM. In conclusion, our results showed a complex interaction between gastrointestinal symptoms, glycemic control, upper gastrointestinal sensory-motor dysfunction, and psychological and nutritional factors, in which anxiety and depression appear to play a special role, since these disturbances were linked to several of the above parameters. Our results reinforce the need for a more effective and comprehensive approach to the psychological and nutritional features in these patients / Doutorado / Clinica Medica / Doutora em Clínica Médica

Orientador: Eros Antonio de Almeida / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T19:20:03Z (GMT). No. of bitstreams: 1 RamirezNunez_WilsonRanu_D.pdf: 1943462 bytes, checksum: 1cb7938d9770774612068d3048db5b0e (MD5) Previous issue date: 2012 / Resumo: O esvaziamento gástrico (EG) consiste na transferência ordenada do conteúdo do estômago para o duodeno, Situações patológicas como alterações hemodinâmicas modificam a velocidade do E.G. e função motora do trato gastrointestinal. O infarto do miocárdio determina retarde do E.G. em ratos, possivelmente pelo estresse causado pela ligadura da artéria coronária. O sistema nervoso central (SNC) afeta as funções motora e secretora gastrintestinais, frente a uma situação de estresse existe aumento da retenção gástrica (RG) induzindo o retarde do E.G. O sistema parassimpático pode estar envolvido neste fenômeno. Por outro lado o sistema simpático controla o E.G., interrompendo a motilidade e a secreção, frente a uma situação de estresse como a do infarto do miocárdio o retarde do E.G., pode estar relacionado à atuação desse sistema. O objetivo deste trabalho foi Avaliar complacência gástrica (CG) em ratos submetidos a infarto recente do miocárdio, participação do nervo vago, sistema nervos simpático, efeito da injeção intra-cerebro-ventricular de GABAb e efeito da lesão do núcleo paraventricular no retarde do EG observado no infarto recente do miocárdio em ratos. Utilizados ratos Wistar, machos, entre 220 - 300g, adaptados ás condições do laboratório, divididos em 3 grupos: grupo INF; grupo SH e grupo NA. Infarto realizado por ligadura da artéria coronária descendente anterior esquerda. Animais após cirurgia permaneceram em jejum alimentar recebendo água ad libitum. Vinte e quatro horas após foi avaliado EG de 1,5 ml/100g de peso do animal de uma refeição de prova (RP) salina marcada com fenol vermelho. EG foi avaliado indiretamente, através da determinação da % de retenção gástrica (RG) da RP, 10 min. após administração orogástrica. Resultados mostraram que para o estudo da complacência gástrica não houve diferença significativa de pressão intragástrica entre os três grupos, nos três pontos de medida da pressão intragástrica (PIG) e em complementação as CGs não apresentaram diferenças significativas quando comparados entre si. No estudo da Vagotomia subdiafragmatica houve diferença significativa das RG (%) entre os subgrupos SH+Sh vs SH+Inf, o subgrupo Vgx+Inf apresentou diferença significativa em relação ao subgrupo SH+Inf e não diferiu do subgrupo Vgx+Sh. Para o estudo do efeito da injeção intra-cerebro-ventricular de GABAb houve diferença significativa entre os grupos SH+Sal e SH+Bac e Inf+Sal e Inf+Bac. No estudo da Simpatectomia química, grupo Inf+Sal apresentou diferença significativa quando comparados aos ratos SH+Sal, e grupo Inf+Pra com grupo SH+Sal não apresentaram diferenças significativas. O grupo Inf+Pra e Inf+Sal apresentaram diferença significativa e ratos SH+Pra e SH+Sal apresentaram diferença significativa quando comparados, No estudo da lesão do Núcleo paraventricular houve diferença significativa das RG (%) entre os subgrupos SH+Sh vs SH+Inf, os grupos PVN+Inf e SH+Inf apresentaram diferença significativa. Conclusões: 1) infarto recente do miocárdio não induz modificações no tônus gástrico em ratos, 2) Existe participação do nervo vago no retarde do EG causado pelo infarto recente do miocárdio, 3) Retardo EG mostrado pelos ratos infartados tem participação, pelo menos em parte, dos receptores alpha-1 adrenérgicos do sistema nervos simpático. 4) Existe participação do núcleo paraventricular no retardo do EG induzido pelo infarto recente do miocárdio / Abstract: Gastric emptying (GE) is the orderly transfer of stomach contents into the duodenum, pathological situations as hemodynamic changes modify GE speed and motor function of the gastrointestinal tract. Myocardial infarction determines GE delayed in rats, possibly due to stress caused by coronary artery ligation. Central nervous system (CNS) affects gastrointestinal secretory and motor functions, in a stressful situation there is increased gastric retention (GR) inducing GE delay. Parasympathetic system may be involved in this phenomenon. On the other hand sympathetic nervous system controls GE, disrupting motility and secretion, compared to a stressful situation such as myocardial infarction, GE delay, may be related to performance of this system. The objective of this study was to evaluate gastric compliance (GC) in rats submitted to recent myocardial infarction, involvement of vagus nerve, sympathetic nervous system, intra-cerebro-ventricular of GABAb injectin effect and paraventricular nucleus lesion effect on GE delay observed in recent myocardial infarction in rats. Used male Wistar rats, between 220-300g, adapted to laboratory conditions, divided into three groups: INF, SH and NA groups. Infarction performed by left anterior descending coronary artery ligation. After surgery, animals were fasted receiving water ad libitum. Twenty four hours after was evaluated GE of 1.5ml/100g body weight of a saline test meal (TM) labeled with red phenol. GE was indirectly estimated by determining % of gastric retention (GR) of test meal. 10 min. after orogastric administration. Results showed that gastric compliance study there was no significant difference in intragastric pressure between the three groups, in the three points of measurement of intragastric pressure (IGP) and complementation in GC showed no significant differences when compared with each other. In subdiaphragmatic vagotomy study, significant difference of GR (%) between subgroups SH+Sh vs SH+Inf, subgroup Vgx+Inf significant difference in the subgroup SH+Inf and did not differ in subgroup Vgx+Sh. To study the effect of intracerebroventricular injection of GABAb significant difference between groups SH+Sal vs SH+Bac and Inf+Sal vs Inf+Bac. To study the chemical simpatectomy by prazosin, the Inf+Sal group showed significant difference when compared to SH+Sal rats, and the group Inf+Pra with SH+Sal group showed no significant difference. The group Inf+Pra and Inf+Sal showed significant differences and the rats SH+Pra and SH+Sal showed significant difference when compared, for the study of the lesion of paraventricular nucleus of GR significant difference (%) between subgroups SH+Sh vs SH+Inf, the group PVN+Inf and SH+Inf showed significant difference. Conclusions: 1) recent myocardial infarction does not induce changes in gastric tone in rats, 2) there is involvement of the vagus nerve in GE delay caused by recent myocardial infarction, 3) GE delayed in infracted rats have participation, at least in part, of alpha-1 adrenergic receptors of the sympathetic nervous system, 4) there is participation of the paraventricular nucleus of GE delayed induced by recent myocardial infarction / Doutorado / Ciencias Basicas / Doutor em Clínica Médica

Ziele dieser Arbeit zum Tränkemanagement bei neonataler Kälberdiarrhoe waren, die Auswirkungen von oralen Rehydratationslösungen (ORL) auf die abomasale Milchgerinnung und den Labmagendurchmesser zu prüfen sowie die Wirksamkeit von unterschiedlich zubereiteten ORL bei bestehender Dehydratation zu vergleichen. Dazu wurden die folgenden zwei Untersuchungen durchgeführt: Die erste Untersuchung an gesunden und durchfallkranken Kälbern sollte mittels Ultraschall zeigen, ob die Einmischung eines bicarbonathaltigen Elektrolytpulvers in die Tränke deren abomasales Gerinnungsverhalten beeinträchtigt. Zeitgleich wurde der ventrodorsale Labmagendurchmesser erfasst, um daraus Rückschlüsse auf die abomasale Entleerung ziehen zu können. Diese Arbeit untersuchte erstmals die Milchgerinnung im Labmagen von spontan an Durchfall erkrankten Kälbern. In der zweiten Untersuchung sollten die Effekte der Fütterung von Milchaustauscher (MAT) sowie von in Wasser und in MAT zubereiteter ORL auf den Flüssigkeits- und Säuren-Basen-Haushalt experimentell dehydrierter Kälber ermittelt werden. Material und Methoden: Bei gesunden (n = 28) sowie durchfallkranken Kälbern (n = 15) wurde das abomasale Gerinnungsverhalten sowie der ventrodorsale Labmagendurchmesser (= Labmagenhöhe) vor und nach Fütterung von Milch bzw. MAT sowie nach Zusatz eines bicarbonathaltigen Elektrolytpulvers zur jeweiligen Tränke ultrasonografisch dargestellt. Im zweiten Untersuchungsteil wurden sechs Kälber nach einem modifizierten Protokoll von WALKER et al. (1998a) experimentell dehydriert. Im Anschluss wurden diese Tiere entweder mit MAT oder mit einer ORL, welche in Wasser (Wasser-ORL) oder MAT (MAT-ORL) zubereitet wurde, gefüttert. In einem weiteren Versuchsdurchlauf verblieben die mittel- bis hochgradig dehydrierten Probanden nüchtern. Nach einem definierten Schema wurden während der Versuchsphase venöse Blutproben vor und nach Induktion einer Dehydratation sowie vor und nach Fütterung entnommen. Es wurden Parameter des Flüssigkeits- und Säuren-Basen-Haushaltes zu den verschiedenen Untersuchungszeitpunkten bestimmt. Ergebnisse: Nach Gabe von Milch konnte mittels Ultraschall immer eine vollständige Zweiphasentrennung in Koagulum und Molke detektiert werden, wohingegen diese nach Fütterung des MAT nur unvollständig voneinander separiert waren. Die kombinierte Fütterung von Milch oder MAT und einer ORL, welche 62 bzw. 93 mmol/l Bicarbonat enthielt, führte zu keinen Unterschieden auf den ultrasonografischen Bildern des Labmageninhaltes im Vergleich zu denen der jeweiligen nativen Tränke. Des Weiteren war die abomasale Milchgerinnung nicht aufgrund eines Durchfallgeschehens gestört. Die unvollständige Gerinnung des MAT resultierte nicht in dessen schnellerer abomasaler Passage, sondern anhand des statistisch signifikant größeren Labmagendurchmessers ab vier Stunden nach MAT-Fütterung scheint es, dass die Entleerung des MAT aus dem Labmagen im Vergleich zu Milch leicht verzögert war. Innerhalb der beiden Versuchstiergruppen konnten keine statistisch signifikanten Unterschiede in Bezug auf den abomasalen Durchmesser zwischen den Tränken mit und ohne ORL-Zusatz festgestellt werden. Die statistisch signifikanten Differenzen des Labmagendurchmessers zwischen den gesunden und durchfallkranken Kälbern nach Fütterung der identischen Tränken weisen darauf hin, dass die Entleerung des Labmagens bei an Diarrhoe erkrankten Kälbern verzögert stattfindet. Bei den experimentell dehydrierten Probanden erhöhte sich das Plasmavolumen statistisch signifikant nach Aufnahme einer Tränkemahlzeit, wohingegen dieses ohne Behandlung konstant blieb. Die Rate der Plasmavolumenexpansion war nach Fütterung von MAT im Vergleich zu Wasser-ORL oder MAT-ORL vermindert. Die Zunahme des Plasmavolumens war bei den dehydrierten Kälbern nach Aufnahme von Wasser-ORL stärker ausgeprägt als nach Fütterung von MAT-ORL. Außerdem war nach Gabe der hypertonen MAT ORL die Plasmaosmolalität statistisch signifikant erhöht. Der Säuren-Basen-Status der Tiere verbesserte sich infolge der Absorption von Flüssigkeit. Dieser Effekt war allerdings weniger offensichtlich, da das Versuchsprotokoll eine hochgradige Dehydratation aber nur eine gering- bis maximal mittelgradige metabolische Azidose induzieren konnte. Schlussfolgerungen: Die unvollständige Gerinnung eines MAT im Labmagen scheint zu keiner schnelleren Entleerung zu führen. Die abomasale Milchgerinnung ist nicht beeinträchtigt, wenn die Milchfütterung mit einer 93 mmol/l Bicarbonat enthaltenden ORL kombiniert wird. Darüber hinaus resultiert aus einer Durchfallerkrankung keine Störung der Milchgerinnung im Labmagen. Die Einmischung eines bicarbonathaltigen Elektrolytpulvers in Milch oder MAT hat keine schnellere abomasale Passage der Ingesta zur Folge. Im Gegensatz zu gesunden Kälbern findet die Entleerung des Labmagens bei durchfallkranken Tieren verzögert statt. Es sind weitere Untersuchungen erforderlich, welche die Ursachen für die verlangsamte abomasale Passage bei an Durchfall leidenden Kälbern bestimmen. Aus den Ergebnissen der vorliegenden Arbeit kann geschlussfolgert werden, dass die gemeinsame Verabreichung von Milch bzw. MAT mit einem bicarbonathaltigen Elektrolytpulver weder die Milchgerinnung noch die abomasale Entleerung der Tränke bei durchfallkranken Kälbern beeinflusst. Folglich ist die Einmischung einer ORL in eine caseinhaltige Tränke möglich. Jedoch zeigen die Ergebnisse der zweiten Untersuchung, dass die Fütterung einer hypertonen MAT-ORL weniger effektiv bei der Erhöhung des Plasmavolumens dehydrierter Kälber ist als das in Wasser zubereitete Äquivalent (Wasser-ORL). Genau genommen erhöht die Verabreichung einer hypertonen MAT-ORL die Plasmaosmolalität bei dehydrierten Tieren, was möglicherweise bei durchfallkranken Kälbern zu einer akuten Kochsalzvergiftung führen könnte. In einer Folgeuntersuchung zu dieser Arbeit konnte gezeigt werden, dass die Gabe von hypertoner Milch-ORL in Kombination mit freiem Zugang zu Wasser eine effektive Behandlungsmaßnahme durchfallkranker Kälber darstellt, da die hohen Elektrolytgaben die Wasseraufnahme der Kälber stimulieren und keine Gefahr einer Hypernatriämie besteht (WENGE et al. 2014). Anhand der beiden Arbeiten kann geschlussfolgert werden, dass durchfallkranke Kälber, denen kein freier Zugang zu Wasser gewährt wird, wasserbasierte, isotone ORL erhalten sollten. / Aims of the present studies on oral rehydration management of calf diarrhoea were to reveal the effects of oral rehydration solutions (ORS) on abomasal milk clotting and abomasal diameter, as well as to compare the effectiveness of differently prepared ORS in calves with experimentally induced dehydration. For this purpose, two experiments were conducted: The first investigation in healthy and diarrhoeic calves should demonstrate via ultrasound whether the incorporation of bicarbonate-containing electrolyte powder into ‘milk meals’ impairs the abomasal coagulation of milk protein. At the same time, the ventrodorsal diameter of the abomasum was measured to outline abomasal emptying. This study is the first in which milk clotting in the abomasum of spontaneously diarrhoeic calves was investigated. The second investigation examined the effects of feeding milk replacer (MR), as well as ORS prepared in water or in MR on the fluid and acid-base balance of experimentally dehydrated calves. Materials and methods: Abomasal curd formation, as well as ventrodorsal diameter (= abomasal height), were ultrasonographically imaged in healthy (n = 28) and diarrhoeic calves (n = 15) before and after feeding milk, MR and ORS containing bicarbonate prepared in milk or MR, respectively. In the second investigation six calves were experimentally dehydrated according to a modified protocol of WALKER et al. (1998a). Subsequently, these calves were fed with either milk replacer (MR) or an ORS prepared in either water (water-ORS) or MR (MR-ORS). In one experiment, the dehydrated calves remained fasting. During the experimental period, venous blood samples were taken according to a defined schedule before and after induction of dehydration, as well as before and after feeding. Parameters of fluid and acid-base balance were determined at various timepoints. Results: After milk-feeding, a complete separation of curd and whey was always detected via ultrasound; whereas after MR-feeding, separation was incomplete. Feeding mixtures of milk or MR with ORS containing 62 - 93 mmol/L bicarbonate did not cause any differences in the ultrasonographic images of abomasal content compared to those of milk or MR. Moreover, abomasal milk clotting was not disturbed due to diarrhoea. Inadequate milk clotting of MR did not result in its faster abomasal passage but according to the significantly larger abomasal diameter starting from 4 h after MR-feeding gastric emptying of MR was slightly decreased when compared to milk. Within the two groups of experimental animals no statistically significant differences could be determined with respect to the abomasal diameter between the diets with and without addition of ORS. Statistically significant differences of abomasal diameter between healthy and diarrhoeic calves after feeding the same diet indicate that abomasal emptying is delayed in calves suffering from diarrhoea. Plasma volume increased significantly following the intake of a ‘fluid meal’ in experimentally dehydrated calves, whereas it remained constant in the absence of treatment. The rate of plasma volume expansion was reduced by feeding MR relative to water-ORS or MR-ORS. In dehydrated calves, the expansion of plasma volume was more pronounced following the intake of water-ORS compared to the feeding MR-ORS. Moreover, plasma osmolality increased significantly following the ingestion of hypertonic MR-ORS. The acid-base status of animals was corrected as a result of fluid absorption, but this effect was less obvious as the experimental protocol resulted in severe dehydration and only mild to moderate metabolic acidosis. Conclusions: Inadequate curd formation of an MR in the abomasum does not result in faster abomasal passage. Milk clotting in the abomasum is not affected when combining milk feeding with ORS containing 93 mmol/L of bicarbonate. Furthermore, abomasal curd formation is not disturbed due to diarrhoea. The addition of an bicarbonate-containing ORS in milk or MR does not result in faster abomasal passage of ingesta. In contrast to healthy calves, abomasal emptying is prolonged in diarrhoeic calves. Hence, further studies are needed to determine reasons for decelerated abomasal passage in calves suffering from diarrhoea. According to the results of the present study it can be concluded that combined feeding of milk/MR with an bicarbonate-containing ORS does not affect either milk clotting or abomasal emptying of the diet in diarrhoeic calves. Consequently, the addition of ORS to milk meal is possible. However, the results of the second investigation indicate that the feeding of hypertonic MR-ORS is less effective in increasing plasma volume of dehydrated calves than the water-based equivalent (water-ORS). In fact, administration of hypertonic MR-ORS increases plasma osmolality in dehydrated calves, potentially causing acute hypernatraemia in diarrhoeic calves. In a follow-up study to the present investigation, it could be demonstrated that feeding hypertonic milk-ORS combined with ad libitum access to water is an effective method of treating diarrhoeic calves because the high electrolyte content stimulates water intake of calves and there is no risk of hypernatraemia (WENGE et al. 2014). Based on these two studies, it can be concluded that diarrhoeic calves without free access to water should receive isotonic water-based ORS.

<p>Obesity and nutrition-related non-communicable diseases continue to be major challenges that are increasing in severity worldwide. Science-centered carbohydrate dietary strategies may be a viable approach to help address such challenges. Recent reports from our laboratory indicate that certain carbohydrates with slow digestion profiles have the ability to trigger the gut-brain axis and reduce food intake and to slow gastric emptying and potentially affect appetite. Slow carbohydrate digestion may have other impacts on energy metabolism that have not been explored. In the current investigations, we sought to better understand the delayed gastric emptying profile of pearl millet-based foods as well as to understand how altering carbohydrate digestion rate impacts substrate utilization for energy.</p> <p>In the first study, the physical breakdown of pearl millet couscous particles in a simulated gastric environment (Human Gastric Simulator) was studied compared to wheat couscous matched in particle size, and select physicochemical properties of each type of couscous were characterized. Because we previously showed that pearl millet couscous had a marked delay in gastric emptying compared to white rice, boiled potatoes, and pasta in a human study in Mali, the objective of the first investigation was to test the hypothesis that pearl millet couscous was more resistant to breakdown in the stomach than wheat couscous and would take longer to empty. Our findings indicated that pearl millet couscous instead broke down into smaller, more numerous particles than wheat couscous. However, pearl millet had a slower starch hydrolysis property compared to wheat couscous per unit surface area. Pearl millet also had a smaller amylose chain length (839-963 DP) compared to wheat (1225-1563 DP), which may enable a denser packing of millet starch molecules that hinders hydrolysis. We also visually observed that the pearl millet particles formed a paste while breaking down that could reasonably generate viscosity in the stomach to potentially delay gastric emptying. </p> <p>Based off the findings from simulated gastric digestion, we next conducted a human study (<i>n</i>=14) in the U.S. to test the hypothesis that pearl millet-based foods (couscous – commercial and self-made, thick porridge) would reduce glycemic response, increase satiety, and delay gastric emptying compared to wheat couscous and white rice. We complemented this human study with additional <i>in vitro </i>work using an advanced gastrointestinal digestion system (TIMagc) to determine if the viscosity of pearl millet couscous particles as they were breaking down in the stomach was contributing to a decrease in gastric emptying. Our findings indicated that all the pearl millet-based foods and wheat couscous had lower overall glycemic response than white rice, but only the self-made millet couscous showed higher satiety through subjective appetitive response ratings. Surprisingly, there were no differences in gastric emptying among the foods. Additionally, the half-emptying times for these foods were all ~3 h, which is similar to the comparably low half-emptying times observed for white rice, boiled potatoes, and pasta in the previous Mali study. We now hypothesize that there may be diet-induced changes in gut-brain axis signaling when slowly digestible carbohydrates are consumed repeatedly over time, perhaps through modulating the number or sensitivity of small intestinal L-cells. We also found that millet couscous did not exhibit high viscosity in the TIMagc, suggesting that viscosity was not impacting its rate of gastric emptying. We conclude that at least some pearl millet-based foods possess a slow digestion property that may act to trigger the gut-brain axis or ileal brake to increase feelings of satiety or slow gastric emptying, but the discrepancy between U.S. and Malian populations requires further study. </p> <p>In the final investigation, we examined how altering carbohydrate digestion affected partitioning of carbohydrate versus fat for oxidation as well as the efficiency of switching oxidation between these two substrates (termed “metabolic flexibility”) in mice. Metabolic flexibility has been associated with good health related to decreased adipose tissue in the body and improved insulin sensitivity and may have implications on weight management. Carbohydrate digestion was adjusted by: (1) testing mice that lacked a complete set of enzymes by knocking out maltase-glucoamylase (Mgam; null) for moderating starch digestion versus testing wild-type mice; (2) using diets in these two groups of mice to moderate starch digestion that had different levels of resistant starch (53%, 35%, and 18%), had only raw corn starch or sucrose, or were high in fat; and (3) providing a supplement of fungal amyloglucosidase (AMG) to the mice treatment groups to increase starch digestion. Respiratory exchange ratio (RER) was measured through indirect calorimetry and mathematical modeling was used to characterize the diurnal shifts in RER (sine equation) as well as carbohydrate versus fat oxidation and metabolic flexibility (percent relative cumulative frequency [PRCF] with Weibull and Mixed Weibull Cumulative Distribution functions). Our results suggest that null mice lacking Mgam had somewhat increased metabolic flexibility than wild-type mice despite exhibiting minimal to no effects on carbohydrate oxidation. Intriguingly, the raw corn starch diet increased fat oxidation and generally promoted metabolic flexibility, although it did not increase carbohydrate oxidation relative to the other carbohydrate-predominant diets. Increasing carbohydrate digestion through AMG supplementation increased carbohydrate oxidation, and generally prompted earlier shifts to carbohydrate oxidation than without AMG supplementation. These findings provide a basis for better understanding the metabolic consequences of altering carbohydrate digestion and establish novel tools that can be utilized in future investigations. Overall, we propose that moderating carbohydrate digestion provides the ideal combination of balancing carbohydrate and fat oxidation while promoting metabolic flexibility. </p> <p>In conclusion, a slow digestion property may enable some types of pearl millet to trigger the ileal brake and gut-brain axis feedback systems to decrease glycemic response and increase satiety. Moreover, consuming carbohydrates with slow digestion may optimize substrate utilization for energy by the body. In addition to triggering the ileal brake and gut-brain axis, modulating carbohydrate digestion to more effectively switch between carbohydrate and fat for oxidation may be beneficial for weight management and metabolic disease prevention.</p>