Effective management of the excreta or faecal sludge (FS) emptying, transport and disposal mechanisms from the on-plot latrines in urban areas of many low-income countries is critical for the sustainability of urban sanitation. However the literature mentions the lack of an effective management system for urban FS emptying, transport and disposal in the low-income countries. The current management of FS has been fragmented and improper with attendant poor health and environmental pollution problems. In particular, no substantive information was found relating to how far the excreta or sludge removed from the latrines is transported to the disposal points. Also information on household financial needs and their perceptions regarding emptying and transport services was lacking. No study had been done regarding the effects of disposal distance and accessibility on the cost of emptying and transport; neither has work been done on FS reuse implications for emptying, transport and disposal mechanisms. Based on these issues, the research questions and hypothesis were formulated to guide the study. Qualitative and quantitative research techniques were used to triangulate and ensure the reliability and validity of the findings and analysis. From the analysis of the findings, the thesis concludes on these key issues: i) Emptying, transport and disposal mechanisms of the excreta and FS as well as the costs of these depend on the type of latrines, latrine use and the technology available for emptying and transport. ii) Owing to the nature of latrines and the emptying methods used the disposal of the FS was indiscriminate and much was found closer to its source of generation. iii) FS was in high demand for reuse but lacked appropriate marketing strategy that could match supply with the demand. iv) The Household Centred Environmental Sanitation (HCES) approach was found to be limited in content and capacity to effectively address the urban excreta and FS emptying, transport and disposal without the active and full involvement of the municipal and local authorities with clear roles and regulations that address the key processes, linkages, and capacity development issues. Thus, the HCES approach needs periodic review and modifications to take care of the new developments and peculiarities of each urban setting. The study also recommends the need to look at streamlining technologies and developing capacity to address cross-cutting issues in urban sanitation. It further recommends the need for households, the sanitation authorities and practitioners to understand the links between latrine technology in terms of type, size, use and location vis-à-vis the required emptying, transport and disposal mechanisms in the urban areas of the low-income countries.

A intolerância gástrica em recém-nascidos prematuros constitui um grande desafio no cuidado neonatal, levando ao uso prolongado de nutrição parenteral e cateteres venosos centrais, aumentando a taxa de infecções neonatais graves e o tempo internação hospitalar dessas crianças. O atraso na maturação da função motora é apontado com o fator determinante da intolerância alimentar dessa faixa etária e a presença de resíduos gástricos a sua principal manifestação clínica. Estudos em adultos mostraram que a velocidade de esvaziamento gástrico é volume dependente, mas em recém-nascidos prematuros este fator não foi adequadamente estudado. O objetivo desse estudo foi avaliar a correlação entre velocidade de esvaziamento gástrico e volume gástrico (em recém-nascidos humanos e ratos), avaliar a influência de fatores pré, peri e pós-natais no esvaziamento gástrico (em recém-nascidos humanos) e estudar os mecanismos fisiológicos que poderiam explicar o efeito do volume na velocidade de esvaziamento gástrico (em ratos). No estudo em humanos, foi realizada a medida da velocidade de esvaziamento gástrico de 20 crianças com idade gestacional entre 28 e 32 semanas através de ultrassonografia, realizada antes e depois da infusão da dieta por sonda orogástrica no primeiro mês de vida. No estudo animal, foi avaliada a velocidade de esvaziamento gástrico de 89 ratos com idade entre 1 e 21 dias através em diferentes tempos de separação materna. Em ambos estudos foi utilizado método de ultrassonografia para estimativa dos valores de esvaziamento gástrico. No modelo animal foram realizadas também medidas de força de contração muscular para diferentes graus de estiramento da parede gástrica. A velocidade de esvaziamento gástrico mostrou correlação importante com o volume gástrico em humanos ((R2 = 0,66 p<0,01) e em ratos (R2 = 0,43 p<0,01) e as crianças com mais de uma semana de vida esvaziam em média 50% do volume oferecido nos primeiros 30 minutos após o término da mamada. As medidas in vitro em ratos mostraram que a contração muscular gástrica induzida por agonista foi diretamente proporcional ao grau do estiramento da parede gástrica e foram mediadas através da via ROCK-2. Em recém-nascidos humanos e ratos o volume gástrico é fator determinante da velocidade de esvaziamento gástrico. Nos ratos, o esvaziamento gástrico não é dependente da idade, mas sim do volume gástrico através da ativação da via ROCK-2, estimulada pelo estiramento da parede gástrica. Em humanos, tipo de leite, uso de ventilação mecânica, tipo de parto, uso de corticosteroide antenatal, uso de antibióticos e/ou antifúngicos, uso de fototerapia não influenciaram a velocidade de esvaziamento gástrico. / Feeding intolerance in preterm infants is a major challenge in neonatal care, leading to a prolonged use of parenteral nutrition and central venous catheters, increasing the rate of severe neonatal infections and the length of hospital stay of these infants. The delay in the maturation of motor function is indicated with the determinant factor of the feeding intolerance of this age group and the presence of gastric residuals its main clinical manifestation. Studies in adults have shown that the rate of gastric emptying is volume dependent. But in preterm infants, this factor has not been adequately addressed. The objective of this study was to evaluate the correlation between gastric emptying rate and gastric volume (in human and rat neonates), to evaluate the influence of pre, peri and postnatal factors on gastric emptying (in human newborns) and to study the physiological mechanisms that could explain the effect of volume on gastric emptying rate (in rats). In the human study, the gastric emptying rate of 20 children with gestational age between 28 and 32 weeks was measured by ultrasonography performed before and after infusion of the diet by gavage in the first month of life. In the animal study, the gastric emptying rate of 89 rats aged 1 to 21 days through at different times of maternal separation was evaluated. In both studies, an ultrasound method was used to estimate gastric emptying values. In the animal model muscle strength measurements were also performed for different degrees of gastric wall stretching. Gastric emptying rate showed a significant correlation with the gastric volume in humans ((R2 = 0.66 p <0.01) and in rats (R2 = 0.43 p <0.01) and in the 30 minutes after feeding 50% of the volume had been emptied. In vitro measurements in rats showed that gastric muscle contraction induced by agonist was directly proportional to the degree of gastric wall stretching and were mediated via upregulation of ROCK-2 activity. In human and rat neonates, the gastric volume is a determinant of gastric emptying rate. In rats, gastric emptying is unrelated to postnatal age but dependent on gastric volume, through the activation of the ROCK-2 pathway, wall strain-induced. In humans, milk type, use of mechanical ventilation, type of delivery, use of antenatal corticosteroids, use of antibiotics and/or antifungals, phototherapy use did not influence gastric emptying rate.

A intolerância gástrica em recém-nascidos prematuros constitui um grande desafio no cuidado neonatal, levando ao uso prolongado de nutrição parenteral e cateteres venosos centrais, aumentando a taxa de infecções neonatais graves e o tempo internação hospitalar dessas crianças. O atraso na maturação da função motora é apontado com o fator determinante da intolerância alimentar dessa faixa etária e a presença de resíduos gástricos a sua principal manifestação clínica. Estudos em adultos mostraram que a velocidade de esvaziamento gástrico é volume dependente, mas em recém-nascidos prematuros este fator não foi adequadamente estudado. O objetivo desse estudo foi avaliar a correlação entre velocidade de esvaziamento gástrico e volume gástrico (em recém-nascidos humanos e ratos), avaliar a influência de fatores pré, peri e pós-natais no esvaziamento gástrico (em recém-nascidos humanos) e estudar os mecanismos fisiológicos que poderiam explicar o efeito do volume na velocidade de esvaziamento gástrico (em ratos). No estudo em humanos, foi realizada a medida da velocidade de esvaziamento gástrico de 20 crianças com idade gestacional entre 28 e 32 semanas através de ultrassonografia, realizada antes e depois da infusão da dieta por sonda orogástrica no primeiro mês de vida. No estudo animal, foi avaliada a velocidade de esvaziamento gástrico de 89 ratos com idade entre 1 e 21 dias através em diferentes tempos de separação materna. Em ambos estudos foi utilizado método de ultrassonografia para estimativa dos valores de esvaziamento gástrico. No modelo animal foram realizadas também medidas de força de contração muscular para diferentes graus de estiramento da parede gástrica. A velocidade de esvaziamento gástrico mostrou correlação importante com o volume gástrico em humanos ((R2 = 0,66 p<0,01) e em ratos (R2 = 0,43 p<0,01) e as crianças com mais de uma semana de vida esvaziam em média 50% do volume oferecido nos primeiros 30 minutos após o término da mamada. As medidas in vitro em ratos mostraram que a contração muscular gástrica induzida por agonista foi diretamente proporcional ao grau do estiramento da parede gástrica e foram mediadas através da via ROCK-2. Em recém-nascidos humanos e ratos o volume gástrico é fator determinante da velocidade de esvaziamento gástrico. Nos ratos, o esvaziamento gástrico não é dependente da idade, mas sim do volume gástrico através da ativação da via ROCK-2, estimulada pelo estiramento da parede gástrica. Em humanos, tipo de leite, uso de ventilação mecânica, tipo de parto, uso de corticosteroide antenatal, uso de antibióticos e/ou antifúngicos, uso de fototerapia não influenciaram a velocidade de esvaziamento gástrico. / Feeding intolerance in preterm infants is a major challenge in neonatal care, leading to a prolonged use of parenteral nutrition and central venous catheters, increasing the rate of severe neonatal infections and the length of hospital stay of these infants. The delay in the maturation of motor function is indicated with the determinant factor of the feeding intolerance of this age group and the presence of gastric residuals its main clinical manifestation. Studies in adults have shown that the rate of gastric emptying is volume dependent. But in preterm infants, this factor has not been adequately addressed. The objective of this study was to evaluate the correlation between gastric emptying rate and gastric volume (in human and rat neonates), to evaluate the influence of pre, peri and postnatal factors on gastric emptying (in human newborns) and to study the physiological mechanisms that could explain the effect of volume on gastric emptying rate (in rats). In the human study, the gastric emptying rate of 20 children with gestational age between 28 and 32 weeks was measured by ultrasonography performed before and after infusion of the diet by gavage in the first month of life. In the animal study, the gastric emptying rate of 89 rats aged 1 to 21 days through at different times of maternal separation was evaluated. In both studies, an ultrasound method was used to estimate gastric emptying values. In the animal model muscle strength measurements were also performed for different degrees of gastric wall stretching. Gastric emptying rate showed a significant correlation with the gastric volume in humans ((R2 = 0.66 p <0.01) and in rats (R2 = 0.43 p <0.01) and in the 30 minutes after feeding 50% of the volume had been emptied. In vitro measurements in rats showed that gastric muscle contraction induced by agonist was directly proportional to the degree of gastric wall stretching and were mediated via upregulation of ROCK-2 activity. In human and rat neonates, the gastric volume is a determinant of gastric emptying rate. In rats, gastric emptying is unrelated to postnatal age but dependent on gastric volume, through the activation of the ROCK-2 pathway, wall strain-induced. In humans, milk type, use of mechanical ventilation, type of delivery, use of antenatal corticosteroids, use of antibiotics and/or antifungals, phototherapy use did not influence gastric emptying rate.

This thesis presents studies relating to the role of the gastrointestinal tract in postprandial blood pressure regulation. The areas that have been addressed include : ( i ) the methodological approaches to the evaluation of gastric emptying, blood pressure, splanchnic blood flow, intraluminal manometry and gut hormones and ( ii ) the pathophysiological mechanisms underlying postprandial hypotension, with a particular focus on ' gastric ' and ' small intestinal ' mechanisms and their potential therapeutic relevance. All of the studies have been either published or manuscripts have been prepared for publication. While scintigraphy represents the ' gold standard ' for the measurement of gastric emptying, recent studies suggest that three - dimensional ( 3D ) ultrasonography may also allow a precise measure of gastric emptying. Concurrent scintigraphic and ultrasonographic measurements of gastric emptying of liquids were performed in healthy young volunteers. There was a good correlation and agreement between scintigraphic measurements of gastric emptying and 3D ultrasonography after ingestion of both low - and high - nutrient drinks, indicating that 3D ultrasonography, provides a valid measure of gastric emptying of liquid meals in normal subjects. Postprandial hypotension, defined as a fall in systolic blood pressure of ≥ 20mmHg,occurring within two hours of a meal is now recognised as an important clinical problem, particularly in the elderly and in patients with type 2 diabetes. The mechanisms mediating postprandial hypotension are poorly understood. The effects of variations in concentration of intraduodenal glucose on the magnitude of the fall in blood pressure were evaluated in healthy elderly subjects. Blood pressure fell, and heart rate and blood glucose increased over time during infusions, however, there was no difference in blood pressure, heart rate or blood glucose concentrations between the study days. These observations suggest that glucose induced postprandial hypotension is a load rather, than concentration, dependent phenomenon. The effect of meal composition has been reported to influence the hypotensive response to a meal and information relating to the effects of triglyceride and protein on blood pressure is inconsistent. The comparative effects of isocaloric and isovolaemic intraduodenal infusions of glucose, triglyceride and protein on the magnitude of the postprandial fall in blood pressure and rise in heart rate and superior mesenteric artery blood flow were evaluated in healthy elderly subjects. There were comparable falls in systolic blood pressure and rises in heart rate, however, the maximum fall in systolic blood pressure occurred later after triglyceride and protein and the stimulation of superior mesenteric artery blood flow was less after protein. These observations suggest that the relatively slower systolic blood pressure response after triglyceride and protein may potentially reflect the time taken for digestion of triglyceride to free fatty acids and protein to amino acids. Acarbose is an antidiabetic drug that slows both gastric emptying and small intestinal glucose absorption. The effects of acarbose, on blood pressure, heart rate, gastric emptying of, and the glycaemic, insulin, glucagon - like peptide - 1 ( GLP - 1 ) and glucosedependent insulinotropic - polypeptide ( GIP ) responses to, an oral sucrose load were evaluated in healthy elderly subjects. Acarbose attenuated the fall in blood pressure and increase in heart rate induced by oral sucrose. Acarbose slowed gastric emptying and was associated with increased retention in the distal stomach. Stimulation of GLP - 1 may contribute to the slowing of gastric emptying and suppression of postprandial glycaemia by acarbose. These findings suggest that acarbose may represent a therapeutic option for the treatment of patients with postprandial hypotension. Recent studies indicate that gastric distension attenuates the postprandial fall in blood pressure. The effects of gastric distension on blood pressure and heart rate during intraduodenal infusion of glucose at a constant load and concentration were evaluated in healthy elderly subjects. Intragastric administration of water markedly attenuated the falls in systolic and diastolic blood pressure induced by intraduodenal glucose. Heart rate increased, with and without gastric distension, in response to intraduodenal glucose infusion but not after intraduodenal saline infusion. This study suggests that gastric distension may potentially be used as a simple adjunctive treatment in the management of postprandial hypotension. Studies employing nitric oxide synthase blockers have established, in animals, that nitric oxide mechanisms are important in the regulation of splanchnic blood flow and, hence, may effect postprandial blood pressure. The role of the nitric oxide synthase inhibitor, NG - nitro - L - arginine - methyl - ester ( L - NAME ), on gastric emptying, postprandial blood pressure, plasma insulin concentration and incretin hormone ( ie GIP and GLP - 1 ) release, following an oral glucose load, were evaluated in healthy elderly subjects. L - NAME attenuated the postprandial fall in blood pressure and increase in heart rate but had no effect on gastric emptying of glucose. L - NAME attenuated the glucose - induced rise in plasma insulin but had no effect on the incretin ( GIP and GLP - 1 ) hormone response to oral glucose. The study indicates that the magnitude of the fall in blood pressure and increase in heart rate and stimulation of insulin secretion induced by oral glucose in healthy elderly subjects are mediated by nitric oxide mechanisms by an effect unrelated to changes in gastric emptying, or the secretion of GIP and GLP - 1. Studies utilising 5 - hydroxytryptamine ( 5 - HT ) infusions in animals have demonstrated regional variations in intestinal blood flow suggesting a role for 5 - HT in postprandial haemodynamic responses. The effects of the 5 - hydroxytryptamine 3 ( 5 - HT3 ) antagonist, granisetron, on the blood pressure, heart rate, antropyloroduodenal motility and glycaemic responses to intraduodenal glucose infusion were assessed in healthy elderly subjects. Granisetron had no effect on blood pressure, heart rate or antral and pyloric motor responses but modulated the duodenal motor response, to intraduodenal glucose. This study indicates that while the cardiovascular response to intraduodenal glucose does not appear to be influenced by the stimulation of 5 - HT3 receptors, this receptor may be involved in the modulation of the duodenal motor activity. / Thesis (Ph.D.)--School of Medicine, 2006.

<p>Postoperative nausea and vomiting (PONV) is still a clinical problem and its incidence is unacceptably high. After the introduction of propofol as an agent for induction and maintenance of anesthesia, it was reported that the incidence of PONV was lower. It was also proposed that propofol possesses antiemetic effects. Dopamine, serotonin and opioids may contribute to PONV. Therefore the purpose of these investigations was to evaluate if propofol has dopamine, serotonin or opioid antagonistic effects and if a subhypnotic infusion of propofol decreases the incidence of PONV. </p><p>Nausea and vomiting were induced in volunteers by a dopamine agonist, apomorphine, and by ipecacuanha which releases serotonin from the enterochromaffin cells in the gut. The effects of propofol on gastric emptying and orocecal transit time were evaluated in volunteers with the paracetamol method and by measuring the endtidal hydrogen concentration after ingestion of the trisaccharide raffinose. The effects of morphine on gastric emptying and gastric tone were studied in patients before surgery with the paracetamol method and with an electronic barostat, respectively. The effects of low dose propofol for prophylaxis of PONV were studied in 172 patients undergoing breast and abdominal surgery. Propofol prophylaxis was compared with a multidrug regimen consisting of dexamethasone and three antiemetic drugs, ondansetron, droperidol and metoclopramide. </p><p>Propofol did not abolish apomorphine-induced vomiting but reduced the number of retchings induced by ipecacuanha. Propofol sedation did not influence gastric emptying of liquids but it slightly prolonged orocecal transit time. Gastric relaxation induced by morphine was abolished by propofol but propofol did not abolish morphine-induced delay of gastric emptying. Propofol in a low dose infusion reduced the incidence of PONV but nausea and especially vomiting increased significantly after termination of the infusion. Pro- phylaxis with the multidrug regimen was very effective in preventing PONV. </p><p>These studies have shown that propofol does not have any dopamine antagonistic effect but may have a weak serotonin antagonistic effect. Propofol cannot abolish morphine-induced delay of gastric emptying. Low dose propofol infusion was effective in preventing PONV as long as the infusion was ongoing but after termination of the infusion nausea and especially vomiting substantially increased. The multidrug regimen (dexamethasone, ondansetron, droperidol, metoclopramide) was very effective in preventing PONV and can be recommended as prophylaxis in patient groups with a known high risk for PONV. </p>

Postoperative nausea and vomiting (PONV) is still a clinical problem and its incidence is unacceptably high. After the introduction of propofol as an agent for induction and maintenance of anesthesia, it was reported that the incidence of PONV was lower. It was also proposed that propofol possesses antiemetic effects. Dopamine, serotonin and opioids may contribute to PONV. Therefore the purpose of these investigations was to evaluate if propofol has dopamine, serotonin or opioid antagonistic effects and if a subhypnotic infusion of propofol decreases the incidence of PONV. Nausea and vomiting were induced in volunteers by a dopamine agonist, apomorphine, and by ipecacuanha which releases serotonin from the enterochromaffin cells in the gut. The effects of propofol on gastric emptying and orocecal transit time were evaluated in volunteers with the paracetamol method and by measuring the endtidal hydrogen concentration after ingestion of the trisaccharide raffinose. The effects of morphine on gastric emptying and gastric tone were studied in patients before surgery with the paracetamol method and with an electronic barostat, respectively. The effects of low dose propofol for prophylaxis of PONV were studied in 172 patients undergoing breast and abdominal surgery. Propofol prophylaxis was compared with a multidrug regimen consisting of dexamethasone and three antiemetic drugs, ondansetron, droperidol and metoclopramide. Propofol did not abolish apomorphine-induced vomiting but reduced the number of retchings induced by ipecacuanha. Propofol sedation did not influence gastric emptying of liquids but it slightly prolonged orocecal transit time. Gastric relaxation induced by morphine was abolished by propofol but propofol did not abolish morphine-induced delay of gastric emptying. Propofol in a low dose infusion reduced the incidence of PONV but nausea and especially vomiting increased significantly after termination of the infusion. Pro- phylaxis with the multidrug regimen was very effective in preventing PONV. These studies have shown that propofol does not have any dopamine antagonistic effect but may have a weak serotonin antagonistic effect. Propofol cannot abolish morphine-induced delay of gastric emptying. Low dose propofol infusion was effective in preventing PONV as long as the infusion was ongoing but after termination of the infusion nausea and especially vomiting substantially increased. The multidrug regimen (dexamethasone, ondansetron, droperidol, metoclopramide) was very effective in preventing PONV and can be recommended as prophylaxis in patient groups with a known high risk for PONV.

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.

This thesis presents studies relating to the role of the gastrointestinal tract in postprandial blood pressure regulation. The areas that have been addressed include : ( i ) the methodological approaches to the evaluation of gastric emptying, blood pressure, splanchnic blood flow, intraluminal manometry and gut hormones and ( ii ) the pathophysiological mechanisms underlying postprandial hypotension, with a particular focus on ' gastric ' and ' small intestinal ' mechanisms and their potential therapeutic relevance. All of the studies have been either published or manuscripts have been prepared for publication. While scintigraphy represents the ' gold standard ' for the measurement of gastric emptying, recent studies suggest that three - dimensional ( 3D ) ultrasonography may also allow a precise measure of gastric emptying. Concurrent scintigraphic and ultrasonographic measurements of gastric emptying of liquids were performed in healthy young volunteers. There was a good correlation and agreement between scintigraphic measurements of gastric emptying and 3D ultrasonography after ingestion of both low - and high - nutrient drinks, indicating that 3D ultrasonography, provides a valid measure of gastric emptying of liquid meals in normal subjects. Postprandial hypotension, defined as a fall in systolic blood pressure of ≥ 20mmHg,occurring within two hours of a meal is now recognised as an important clinical problem, particularly in the elderly and in patients with type 2 diabetes. The mechanisms mediating postprandial hypotension are poorly understood. The effects of variations in concentration of intraduodenal glucose on the magnitude of the fall in blood pressure were evaluated in healthy elderly subjects. Blood pressure fell, and heart rate and blood glucose increased over time during infusions, however, there was no difference in blood pressure, heart rate or blood glucose concentrations between the study days. These observations suggest that glucose induced postprandial hypotension is a load rather, than concentration, dependent phenomenon. The effect of meal composition has been reported to influence the hypotensive response to a meal and information relating to the effects of triglyceride and protein on blood pressure is inconsistent. The comparative effects of isocaloric and isovolaemic intraduodenal infusions of glucose, triglyceride and protein on the magnitude of the postprandial fall in blood pressure and rise in heart rate and superior mesenteric artery blood flow were evaluated in healthy elderly subjects. There were comparable falls in systolic blood pressure and rises in heart rate, however, the maximum fall in systolic blood pressure occurred later after triglyceride and protein and the stimulation of superior mesenteric artery blood flow was less after protein. These observations suggest that the relatively slower systolic blood pressure response after triglyceride and protein may potentially reflect the time taken for digestion of triglyceride to free fatty acids and protein to amino acids. Acarbose is an antidiabetic drug that slows both gastric emptying and small intestinal glucose absorption. The effects of acarbose, on blood pressure, heart rate, gastric emptying of, and the glycaemic, insulin, glucagon - like peptide - 1 ( GLP - 1 ) and glucosedependent insulinotropic - polypeptide ( GIP ) responses to, an oral sucrose load were evaluated in healthy elderly subjects. Acarbose attenuated the fall in blood pressure and increase in heart rate induced by oral sucrose. Acarbose slowed gastric emptying and was associated with increased retention in the distal stomach. Stimulation of GLP - 1 may contribute to the slowing of gastric emptying and suppression of postprandial glycaemia by acarbose. These findings suggest that acarbose may represent a therapeutic option for the treatment of patients with postprandial hypotension. Recent studies indicate that gastric distension attenuates the postprandial fall in blood pressure. The effects of gastric distension on blood pressure and heart rate during intraduodenal infusion of glucose at a constant load and concentration were evaluated in healthy elderly subjects. Intragastric administration of water markedly attenuated the falls in systolic and diastolic blood pressure induced by intraduodenal glucose. Heart rate increased, with and without gastric distension, in response to intraduodenal glucose infusion but not after intraduodenal saline infusion. This study suggests that gastric distension may potentially be used as a simple adjunctive treatment in the management of postprandial hypotension. Studies employing nitric oxide synthase blockers have established, in animals, that nitric oxide mechanisms are important in the regulation of splanchnic blood flow and, hence, may effect postprandial blood pressure. The role of the nitric oxide synthase inhibitor, NG - nitro - L - arginine - methyl - ester ( L - NAME ), on gastric emptying, postprandial blood pressure, plasma insulin concentration and incretin hormone ( ie GIP and GLP - 1 ) release, following an oral glucose load, were evaluated in healthy elderly subjects. L - NAME attenuated the postprandial fall in blood pressure and increase in heart rate but had no effect on gastric emptying of glucose. L - NAME attenuated the glucose - induced rise in plasma insulin but had no effect on the incretin ( GIP and GLP - 1 ) hormone response to oral glucose. The study indicates that the magnitude of the fall in blood pressure and increase in heart rate and stimulation of insulin secretion induced by oral glucose in healthy elderly subjects are mediated by nitric oxide mechanisms by an effect unrelated to changes in gastric emptying, or the secretion of GIP and GLP - 1. Studies utilising 5 - hydroxytryptamine ( 5 - HT ) infusions in animals have demonstrated regional variations in intestinal blood flow suggesting a role for 5 - HT in postprandial haemodynamic responses. The effects of the 5 - hydroxytryptamine 3 ( 5 - HT3 ) antagonist, granisetron, on the blood pressure, heart rate, antropyloroduodenal motility and glycaemic responses to intraduodenal glucose infusion were assessed in healthy elderly subjects. Granisetron had no effect on blood pressure, heart rate or antral and pyloric motor responses but modulated the duodenal motor response, to intraduodenal glucose. This study indicates that while the cardiovascular response to intraduodenal glucose does not appear to be influenced by the stimulation of 5 - HT3 receptors, this receptor may be involved in the modulation of the duodenal motor activity. / Thesis (Ph.D.)--School of Medicine, 2006.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 6 uppsatser.

Waste Management is one of the biggest challenges for modern cities caused by urbanisation and increased population. Smart Waste Management tries to solve this challenge with the help of techniques such as Internet of Things, machine learning and cloud computing. By utilising smart algorithms the time when a recycling container is going to be full can be predicted. By continuously measuring the filling level of containers and then partitioning the filling level data between consecutive emptyings a regression model can be used for prediction. In order to do this an accurate emptying detection is a requirement. This thesis investigates different data-driven approaches to solve the problem of an accurate emptying detection in a setting where the majority of the data are non-emptyings, i.e. suspected emptyings which by manual examination have been concluded not to be actual emptyings. This is done by starting with the currently deployed legacy solution and step-by-step increasing the performance by optimisation and machine learning models. The final solution achieves the classification accuracy of 99.1 % and the recall of 98.2 % by using a random forest classifier on a set of features based on the filling level at different given time spans. To be compared with the recall of 50 % by the legacy solution. In the end, it is concluded that the final solution, with a few minor practical modifications, is feasible for deployment in the next release of the system.