Orientadores: Maria Beatriz Puzzi Taube, Mario Jose Abdalla Saad / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-07-24T14:59:35Z (GMT). No. of bitstreams: 1 Pires_FernandaEspinosa_M.pdf: 2161075 bytes, checksum: 364c4c8044d9ce8ac17ea12e73f17c02 (MD5) Previous issue date: 1998 / Resumo: A Acantose Nigricante (AN) benigna está associada a diversas endocrinopatias e alterações metabólioa., particularmente a resistencia insulinica. A dermatose " encontrada mais freqüentemente nos pacientes obesos, e obesidade é uma condição de resistência insulínica. Alguns trabalhos têm mostrado associação de resistência insulínica com presença de depósito de mucopolissacárides na derme papilar em cortes histológicos de AN. Este estudo foi realizado com o objetivo de se avaliar a resposta insulínica após o teste oral de tolerância à glicose (TaTO) em obesos com AN e comparar com grupos controle, além de correlacionar com os aspectos histopatológicos e histoquímicos. Para tanto, foram avaliados 33 pacientes: 14 Obesos com AN (Grupo 1), 9 Obesos Normais (Grupo 2), e um grupo controle de 10 pacientes com peso normal. Para o estudo histológico, foi possível obter análise de 13 pacientes obesos com AN, 8 pacientes obesos sem AN e 9 pacientes de peso normal. Foram avaliados os níveis de insulina ao jejum, aos 120', a área sob a curva de insulina e os índices insulinogênicos (O', 120' e área). Biópsias de pele foram analisadas pela coloração pelo ferro coloidal para pesquisa de mucopolissacárides na lesão cutânea e nos grupos controle, na mesma região anatômica. Os resultados mostraram diferença significativa na insulina aos 120' do TaTG entre os grupos 1 e 2 (p<0,05), e o índice insulinogênico aos 120' mostrou valores muito próximos do limite da significância estatística (p=0,053). Ao estudo de correlação, quando analisados os 3 grupos em conjunto, foi observado correlação linear positiva entre níveis de insulina (120', índice insulinogênico aos 120', área de insulina e índice de área de insulina) e espessura da epiderme e camada córnea(p<0,05) e entre medidas da papila e índice de área de insulina (p<0,05). Não houve diferenças à coloração pelo ferro coloidal na área da AN, comparada com os grupos controle. Pacientes obesos sem AN apresentaram maior área de insulina (p<O,05) quando comparados com pacientes magros sem AN, a despeito das medidas do epitélio e papila serem próximas, o que sugere que níveis altos de insulina isoladamente não justificam a lesão dermatológica.Conclui-se que obesos com AN apresentam resistência insulínica maior que obesos sem AN, que a resistência insulínica não está associada à maior presença de mucopolissacárides na derme e que níveis sangüíneos de insulina estão associados à espessura da epiderme e camada córnea. Em contrapartida, níveis altos de insulina isoladamente não justificam a lesão dermatológica. A presença de mucopolissacárides na derme papilar na região da axila mostrou ser esse um achado normal. O presente trabalho sugere influência da insulina no crescimento epitelial. Palavras-chave: Acantose Nigricante, Resistência Insulínica, Obesidade, Ferro Coloidal, Mucopolissacárides / Abstract: Benign Acanthosis Nigricans (AN) is associated to many endocrinopathies and metabolic disturbs, specially insulin resistance. The dermatosis is more ftequently found in obese patients, and obesity is a condition of insulin resistance. Some papers have shown allociatiôn ôf inlulin reli'tanoê e:rtd preliênoe of muoopolyaacoharidês in detmiíl on histological slides of AN. This study was performed to. evaluate the insulin response to the oral test of glucose tolerance in obese patientes with AN comparing with control groups, and to correlate it with histopathological and histochemical findings. For this purpose, 33 patientes were studied in 3 groups: 14 obese with AN (Group 1),9 normal obese (Group 2) and 10 nomallean (qt"oup 3). For histological analyzes, 13 patients were studied in group I,' 8 patients in group 2 and 9 patients in group 3. Insulin levels at O', 120', insulin area, insulinogen index'(at O', 120' and area) were evaluated. Skin biopsies were performed by the colloidal iron method to evaluate mucopolysaccharide presence in skin lesions of AN and incontrol. groups, in the same anatomic site. There was statistically difference on insulin of 2 hours after glucose overload between groups 1 and 2 (p<0,05), and the insulinogen index of 2 hours after glucose overload were near the significance limit (p<0,053). When the 3 groups were analysed together, there was positive linearcorrelation between insulin levels (at 120', insulinogen index at 120', insulin area and insulinogen index of area) and epitheliuÍn and homy layer thickness (p<0,05), and between papilla measurement and area insulinogen index. There wasn't difference at colloidal iron staining in AN slides, comparing with control groups. Obese patients without AN shows higher instllin area, comparing with lean patients without AN (p<0,05) in spite of close epithelium and papilla measurements, wich is suggestive that only high insulin levels does not justify the dermatologic lesion. In conclusion, obese patients with AN shows more insulin resistance than obese patients without AN, insulin resistance is not associated to more amount of mucopolysaccharides in dermis and insulin levels are correlated to . epithelium and homy layer thickness. In counterpart, on1y lúgh insulin levels does not justify the dermatologic lesion. Mucopolysaccharides in dermal papilla ofaxilar region is a normal finding. Tlús work suggests insulin influence on epithelial growth. Keywords: Acanthosis Nigricans, Mucopolysaccharides, Insulin Resistance, Obesity, Colloidal Iron / Mestrado / Mestre em Medicina

Orientador: Mario Jose Adballa Saad / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-07-26T00:38:58Z (GMT). No. of bitstreams: 1 Paez-Espinosa_EnmaVeronica_D.pdf: 10014657 bytes, checksum: e7924ea843e909899d5fbe8eb873b33b (MD5) Previous issue date: 2000 / Resumo: A insulina inicia seus efeitos metabólicos e promotores de crescimento através da ligação à subunidade a do seu receptor. Esta ligação promove a fosforilação em tirosina da subunidade _, e dá inicio a uma cascada de eventos intracelulares, mediante a fosforilação de vários substratos endógenos. Entre os primeiros substratos ativados estão o substrato 1 do receptor de insulina, e uma nova proteína, possuidora .do domínio SH2, cuja estrutura lembra àquela do colágeno (Src homology), denominada Shc. No presente estudo, determinamos a capacidade do receptor de insulina ativado de induzir a fosforilação em tirosina da proteína Shc, assim como a associação Shc-Grb2 em figado, músculo e tecido adiposo de ratos nonnais e ratos submetidos a cinco situações experimentais de resistência à insulina i.e., jejum prolongado, tratamento crônico com dexametasona, envelhecimento, tratamento agudo com adrenalina e diabetes induzida por estreptozotocina. Os resultados demonstraram que após infusão de concentrações fisiológicas de insulina em ratos nonnais, a Shc é substrato do receptor de insulina, cujo pico ,Ae fosforilação acontece 5 minutos após a infusão de insulina nos três tecidos estudados, e se associa à Grb2. Ratos em jejum, uma situação aguda de resistência à insulina que cursa com baixos níveis de glicose e insulina plasmáticas, apresentaram significativa diminuição do grau de fosforilação da Shc induzi da por insulina em figado (50%) e gordura (62%), em relação aos seus controles. Por outro lado, a infusão de insulina em ratos portadores de diabetes mellitus induzida por estreptozotocina, estado caracterizado por apresentar elevados níveis de glicose sanguínea associados a baixas concentrações de insulina plasmática, levou a um significativo incremento do grau de fosforilação da. Shc em figado (175%), músculo (180%) e gordura (133%), em relação aos controles (100%). Embora ambos os modelos experimentais apresentaram baixos níveis de insulina plasmática, as características de fosforilação da Shc foram opostas. Este resultado sugere que em modelos agudos de resistência à insulina, a concentração plasmática de glicose circulante é o principal parâmetro que determina a indução da fosforilação da proteína Shc nos tecidos estudados. Não foi observada variação nos níveis de fosforilação em tirosina em figado, músculo ou gordura de ratos tratados agudamente com adrenalina após estímulo com insulina, embora um aumento estatisticamente significativo nos níveis basais de associação Shc/Grb2 foi evidenciada nos três tecidos estudados nestes anImais. Em animais portadores de hiperinsulinemia crônica (ratos velhos ou tratados com dexametasona), houve um aumento da fosforilação em tirosina da Shc induzida por insulina nos tecidos hepático (64% e 58%) e muscular (81 % e 64%) de ratos com 20 meses ou tratados com glicocorticoides, respectivamente. Em ratos velhos, incremento foi evidenciado também em tecido adiposo (76% acima do controle). Estes resultados sugerem que, em situações crônicas de resistência à insulina, a hiperinsulinemia pode ser um dos fatores responsáveis do aumento de fosforilação da Shc observada nestes animais. Para todos os tecidos e modelos experimentais estudados, esta regulação demonstrou ser independente dos níveis protéicos da proteína Shc, que permaneceram inalterados, mas o grau de fosforilação em tirosina parece detenninar a capacidade de associação da Shc com a proteína adaptadora Grb2. Nossos resultados demonstram que, em tecidos animais, a Shc é susceptível de ser tirosino-fosforilada pela insulina através do seu receptor. Esta fosforilação é tempo- e dose- dependente, e sua intensidade determina as capacidade. De associação da Shc com a proteína adaptadora Grb2. Tanto o grau de fosforilação da Shc quanto a associação Shc/Grb2, apresentam regulação diferenciada, dependente do modelo de resistência à insulina e do tecido analisado, mas parece que os níveis de insulina podem contribuir para essa regulação. A fosforilação da Shc induzida pela insulina nos modelos descritos, apresentou características diferentes daquelas exibidas pelo substrato-l do receptor de insulina, observadas em estudos prévios realizados em ratos sujeitos a idênticas condições experimentais, sugerindo uma dissociação no padrão de comportamento destas duas proteínas, após serem ativadas pela insulina / Abstract: Shc is a novel type of tyrosine-phosphory lated protein activated in response to a wide variety of polypeptide ligands. In this report, we used immunoprecipitation and immunoblotting to examine the effect of insulin on Shc tyrosine phosphorylation and Shc/Grb2 association in insulin-sensitive tissues of the intact rat. Following an infusion of insulin, Shc was tyrosine phosphorylated in the liver, skeletal musc1e and adipose tissue in a time- and dose-dependent fashion, which peaked 5 min after exposure to the hormone and, except in the case of adipose tissue, retumed to basal values after 15 mino There was coimmunoprecipitation of Shc and the insulin receptor after stimulation with insulin. Receptor tyrosine kinase activity toward Shc was also observed. Following an infusion ofinsulin, Shc was found to associate with Grb2. Insulin-induced Shc phosphorylation and Shc/Grb2 association were also investigated in five animal models of insulin resistance (72-h starvatation, chronic dexamethasone treatment, aging, acute epinephrine treatment and STZ induced diabetes mellitus). There were no differences in Shc protein expression between tissues from control and insulin resistant animaIs. In all the tissues and animal models studied, the Shc/Grb2 association were directly correlated with the levels of Shc phosphorylation reached after insulin infusion. In fasted hypoinsulinemic rats th_re was a d_crease in insulin-induced Shc phosphorylation in liver and adipose tissue. However, a significant increase _n Shc phosphorylation was observed in liver, musc1_ and fat from STZ-treated rats, another insulin-resistant state wh.ich cóúrses with low insulin levels, but high plasmatic glucose concentrations. Other insulin-resistant states which courses with hyperglicemic levels like dexamethasone-treated rats and aging, showed similar results to those observed in diabetic rats. Liver and musc1e of hypercortisolemic rats showed a significant increase in insulin-induced Shc tyrosine phosphorylation, so as liver, musc1e and adipose tissue of 20 months-old rats. Interestingly, acute stimulus with epinhephrine, a normoglicemic condition, did not display changes in insulin-induced Shc tyrosil phosphorylation nor Shc/Grb2 association in the three tissues studied. These results indicate that Shc tyrosil phosphorylation and Shc/Grb2 association are regulated in the different type af insulin resistance and that this regulation seems to be related to the plasmatic glucose and insulin levels found in these animals / Doutorado / Fisiologia / Doutor em Biologia Funcional e Molecular

Orientador: Ricardo de Lima Zollner / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-04T10:18:52Z (GMT). No. of bitstreams: 1 Ashimine_Rika_M.pdf: 5750364 bytes, checksum: 6e356464e821f803ab86ff8474edb56f (MD5) Previous issue date: 2004 / Resumo: A insulite está presente em ambos os sexos do camundongo NOD (non obese diabetic), enquanto a incidência do diabetes tem alta prevalência em fêmeas. O diabetes manifesta-se em 90% das fêmeas e aproximadamente em 20% nos machos. Neste estudo, investigamos o efeito da testosterona na incidência do diabetes e no perfil de citocinas Th1 no pâncreas e em células esplênicas do camundongo fêmea NOD. Nós utilizamos diferentes doses in vitro (5, 10, 20 e 30nM) e in vivo (174JlMe 348JlM)com administração semanal e mensal. Os camundongos fêmeas foram mantidos em tratamento durante 28 semanas, iniciando na 48 semana de vida. Para os estudos in vivo o tratamento semanal e mensal com 174JlM de testosterona reduziu a incidência do diabetes em 40%, enquanto o tratamento semanal com 348JlMreduziu a incidência do diabetes a 20%, índice semelhante ao do macho, com menor índice de insulite. No pâncreas, o perfil de citocinas Th1 estava aumentado no grupo de animais tratados diabéticos que no grupo de camundongos não diabéticos. Semelhante aos resultados do estudo in vivo, os efeitos da testosterona in vitro sobre as citocinas Th1 de células esplênicas exibiram tempo e dose-dependência. Contudo, o efeito da testosterona in vivo sobre a diminuição do IFN-y foi mais proeminente. O efeito da testosterona sobre a ativação da Stat3, Stat4, Jak2 e Tyk2 evidenciou que o estímulo a fosforilação de Jak2 e a fosforilação de Stat3 reduzida é dose-dependente. Estes resultados reforçam os efeitos da testosterona sobre a incidência do diabetes tipo 1 e sua modulação nos níveis de citocinas Th1e na fosforilação dos fatores de transcrição no pâncreas e em células esplênicas no camundongo NOD / Abstract: Insulitis is present in both gender of non-obese diabetic (NOD) mice, where as the incidence of diabetes is much higher in females; overt diabetes appears in 90% of females and approximately 20% of males. In this study, we investigated the effect of testosterone on the incidence of diabetes and the Th1 cytokine profile in pancreas and spleen cells in female NOD mice. Testosterone was employed at different doses (in vivo 174uM and 348uM; and 5, 10, 20 or 30nM in vitro) and with variable frequencies (weekly and monthly) of administration., Female mice were maintained under treatment for 28 weeks, starting from the 4thweek of life. Diabetes was diagnosed by two consecutive blood glucose levels > 250mg/dL. For in vivo studies, the weekly and monthly schedule of 174J..lM testosterone treatment reduced the incidence of diabetes to 40% whilst the weekly dose of 348J..lMreduced the incidence to 20%, an incidence similar that of male diabetes with a lower insulitis index. In pancreas, the Th1 cytokine profile was higher in treated diabetic than non-diabetic mice. Similarly to in vivo studies, the in vitro effects of testosterone on spleen cells Th1 cytokine were time and dose dependent. However, in vivo, decrease in IFN-y was more prominent. Testosterone activation of Stat3, Stat4, Jak2 and Tyk2 induced a dose dependent increase in Jak2/Py and a decrease in Stat3/Py. These results demonstrate the effect of testosterone on the incidence type 1 diabetes and its modulation of the Th1 cytokine and transcription factor phosphorylation in NOD mice / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista / Introducción: Diabetes Mellitus tipo 2 (DM2) es una enfermedad que afecta el metabolismo de los carbohidratos. Su descompensación metabólica, medida con el test de hemoglobina glicosilada (HbA1c≥7%), se traduce en complicaciones sistémicas y orales, como enfermedad periodontal y disminución del flujo salival. Esto último, no necesariamente se relaciona al padecimiento de xerostomía (sensación de boca seca), altamente asociada en diabéticos, por lo que esta sensación podría estar determinada por otros factores que pueden alterarse según control metabólico en diabetes, como pH salival, concentración de proteínas salivales y consumo de fármacos antihipertensivos. No existe suficiente evidencia que compare estos parámetros entre sujetos con DM2 compensados y descompensados, por lo que el objetivo de este trabajo es comparar la prevalencia de xerostomía entre sujetos diabéticos compensados y descompensados metabólicamente y relacionar este parámetro con diferencias en la velocidad de flujo salival, concentración de proteínas salivales, pH salival y consumo de fármacos antihipertensivos. Material y métodos: De la Asociación de Diabetes de Chile, se reclutaron 50 sujetos DM2, compensados (HbA1c<7%) y descompensados (Hba1c≥7%). Se determinó xerostomía, pH salival, concentración de proteínas en saliva (PP) y velocidad de flujo salival (VFS) y se describió el consumo de fármacos antihipertensivos según lo encontrado en fichas clínicas. Para comparar pH, VFS, PP entre xerostómicos y no xerostómicos y entre DM2 compensados y no compensados, se utilizaron las pruebas t-Student y Mann-Withney. Para asociar el padecimiento de HTA y el consumo de fármacos antihipertensivos con xerostomía se utilizó chi cuadrado, considerándose una significancia del 95% (p<0,05). Resultados: De la muestra, 25 sujetos eran compensados y 25 descompensados. 13 (26%) eran hombres y 37 (74%) mujeres. La prevalencia de xerostomía fue mayor en descompensados, sin embargo esta diferencia no fue estadística. Sujetos DM2 descompensados presentaron menor pH (7.47), menor VFS (0.54 ml/min) y mayor PP (35.41 µg/ml) en comparación con DM compensados (pH=7.74, VFS=0,64 ml/min, PP=31.79 µg/ml), siendo la diferencia de pH, la única estadística (p<0,05). No hubo relación entre consumo de fármacos antihipertensivos y xerostomía. Conclusión: Xerostomía se presentó en sujetos con DM2 compensados y descompensados. Si bien, hubo diferencias al comparar pH salival entre estos grupos, ni ésta ni las otras variables estudiadas, se relacionaron con xerostomía, dando cuenta de la multifactorialidad de este fenómeno. / Adscrito a Proyecto FIOUCH 13-002

Class of 2014 Abstract / Specific Aims: To assess the effect of aerobic exercise dose has on diabetes control monitoring parameter of HbA1c and BMI. Methods: Studies were found from previous studies and through a search of PubMed. These studies were screened for eligibility and data was extracted using a data extraction tool. The outcomes of HbA1c and BMI were analyzed using Comprehensive Meta-Analysis software and standardized mean difference (SMD) was used to assess the impact of different doses of exercise on the outcome measures. Variability was measured using the I2 statistic and publication bias was assessed. Main Results: Nineteen studies met inclusion criteria and were analyzed. Moderate dose aerobic exercise was found to have moderate effect in reducing HbA1c and BMI (p = 0.00 & 0.03 respectively). Low dose and high dose aerobic exercise were not to reduce HbA1c (p = 0.07 & 0.13) or BMI (p = 0.61 & 0.25). There was excess variation found in both the HbA1c analysis and the BMI analysis (I2 = 72.28 & 84.04 respectively). There was no publication bias found (Kendall’s tau = 0.809). Conclusion: Moderate dose aerobic exercise was effective in reducing HbA1c and BMI, while low dose and high dose aerobic exercise were not found to have a statistically significant effect on either HbA1c or BMI.

This diploma thesis analyses non-compliance phenomenon incidence rate of patients diagnosed for diabetes mellitus. Theoretical part studies non-compliance phenomenon and characteristics of diabetes mellitus disease. Practical part evaluates information resulting from questionnairing.

XVI Congreso Argentino y VIII del Cono Sur de Soporte Nutricional y Metabolismo. IV Congreso Argentino de Soporte Nutricional y Metabolismo en Pediatría. Evento desarrollado en Rosario, Argentina del 27 al 29 de Octubre del 2013. / OBJETIVO: Determinar el nivel de conocimientos sobre el manejo de la diabetes en pacientes ambulatorios del CEDHI. METODOLOGÍA: Estudio descriptivo transversal Población: Pacientes ambulatorios de ambos sexos del CEDHI. Tamaño de muestra: 33 pacientes RESULTADOS: La edad de los encuestados se concentró en mayores de 65 años (67%), se encuesto a más mujeres que varones (53% y 47%), de los cuales el 20% presentaban la enfermedad hace menos de 1 año, el 29% hace menos de 5 años, el 27% de 5 a 10 años y el 24% mayor a 10 años. Sobre el tratamiento de la DM, el 85% piensa que se controla, mientras que el 9% piensa que no se cura y el 3% que si se cura, respecto a que órganos afecta la DM el 48% presento un nivel de conocimientos suficiente, mientras que el 39% fue moderado y el 12% insuficiente, respecto a la importancia por especialidades se encontró que un 94% considera importante la evaluación por la especialidad de nutrición, seguido por cardiología y oftalmología (82% y 79% respectivamente).

Heart failure (HF) is one of the commonest complications of Diabetes Mellitus (DM) with the prevalence of DM reported at around 30% in many pivotal heart failure studies. However the pathophysiological mechanisms that contribute to HF development in diabetes are poorly understood. To investigate this we used a novel human relevant mouse model of DM (GENA348) in which there is a point mutation in the glucokinase (Gck) gene, the glucose sensor which regulates insulin secretion. A mutation in the same gene is known to underlie Maturity Onset Diabetes of the Young Type 2 (MODY 2) in humans. The mutant mice developed significant hyperglycaemia with normal insulin levels due to the altered glucose sensing. We examined the molecular mechanisms that contribute to the HF phenotype in DM. Mean random blood glucose was found to be increased in the GENA348 mutant(HO) mice compared to wild type (WT) litter mates (WT 6.9±0.3mmol/L vs HO20.6±0.8mmol/L, P<0.001). Serial echocardiography was performed, at 3, 6 and 12 months. No significant changes in echocardiographic parameters were observed at 3 months, although by 6 months development of significant cardiachypertrophy in HO mice was observed characterised by a 20% increase in the diastolic posterior wall thickness (dPW). At 12 months of age left ventricular dilatation was also evident. Systolic function was preserved although significant diastolic dysfunction was evident at 6 and 12 months. Histological staining illustrated significant cellular hypertrophy with real time PCR data demonstrating a relative 150% increase in the hypertrophic marker BNP. Hypertrophic pathways were examined through western blot analysis revealing an age dependent increase in Akt phosphorylation (6 months-140%, 12 months-460%). Serum levels of advanced glycation end products (AGEs) and expression of their receptors RAGE were also elevated. In vitro cellular experiments also revealed AGEs directly activate Akt through phosphorylation and increase levels of the receptor RAGE. AGE induced phosphorylation of Akt is inhibited in the presence of wortmannin, suggesting a PI3K dependent signalling mechanism. Wortmannin blocked the development of cardiac hypertrophy in the diabetic mice. In conclusion we demonstrate that the human relevant GENA348 mouse model of diabetes develops a progressive cardiac phenotype including cardiachypertrophy, LV dilatation and diastolic dysfunction similar to the clinical manifestations of diabetic cardiomyopathy. We propose a novel RAGE/PI3K/Akt pathway that for the first time provides insight into the molecular mechanisms that underlie the development of HF. Moreover, we show raised glucose alone is able to cause cardiotoxicity independently of insulin.

Chronic diabetic patients have a higher incidence of and mortality from cardiac disease. A wide spectrum of cardiac problems plague the chronic diabetic including coronary artery disease, congestive heart failure and diabetic cardiomyopathy. Cardiac disease in the diabetic is not simply due to accelerated atherosclerosis alone, but is also due to a combination of microangiopathy, autonomic neuropathy, and various other factors which produce biochemical, functional and structural alterations in the heart. Recently, cardiac function was studied in animals with experimentally-induced diabetes and cardiac-dysfunction was reported in acute as well as chronic phases of experimental diabetes. Since cardiac disease is a consequence of long-standing diabetes in diabetic patients, investigation of myocardial function at various time points after induction of experimental diabetes would yield information regarding the development and progression of cardiac dysfunction in diabetes. We. therefore investigated cardiac function and pharmacology in isolated perfused working hearts obtained from 7, 30, 100, 180, 240 and 360-day alloxan and streptozotocin (STZ) diabetic and age-matched control hearts. Diabetes was induced in the rat by injecting either alloxan (65 or 40 mg/kg) or STZ (50 or 60 mg/kg) into the tail vein. Diabetic and age-matched control rats were sacrificed at various time points after the induction of diabetes and hearts were isolated and perfused on a working heart apparatus. Cardiac function was studied at various left atrial filling pressures and was expressed in terms of left ventricular developed pressure (LVDP), rate of rise of left ventricular pressure (positive dP/dt) and rate of decline of left ventricular pressure (negative dP/dt). Dose-response curves to carbachol and isoproterenol were also performed. Blood samples were collected at the time of sacrifice, serum was separated and analyzed for insulin and glucose content. Both alloxan and STZ produced diabetes in the rat as shown by fasting hypoinsulinemia and hyperglycemia. Cardiac function was not altered in 7-day alloxan and STZ diabetic rats. Depressed function at various left atrial filling pressures was seen in hearts isolated from 30-day alloxan diabetic rats but not in 30-day STZ diabetic rats. Hearts isolated from 100-day alloxan and STZ diabetic rats, 180- and 360-day STZ diabetic rats and 240-day alloxan diabetic rats, all exhibited cardiac functional abnormalities. Cardiac functional abnormalities observed in d.iabetic rats were, depressed >LVOP and -positive«.and negative dP/dt at high left atrial filling pressures. Diabetic rat hearts exhibited no change in either sensitivity or responsiveness to the negative inotropic effect of carbachol at 7 and 30 days after induction of the disease. A sub-sensitivity to carbachol was observed in diabetic rat hearts at 100 days after induction of diabetes as compared to age-matched control rat hearts. However, 180- and 240-day diabetic rat hearts exhibited supersensitivity to the negative inotropic effect of carbachol. Isoproterenol produced an identical positive inotropic effect in control as well as diabetic rat hearts at all of the time points studied. However, the maximum changes produced by isoproterenol in negative dP/dt of diabetic rat hearts were depressed at various time points as compared to those in age-matched control rat hearts. We also studied the effect of isoproterenol on the cyclic AMP content and phosphorylase a activity in hearts obtained from 3 and 100 to 120 day control and diabetic rats. Basal cyclic AMP content and phosphorylase a activity were not altered in acute and chronic diabetic and age-matched control rat hearts. Isoproterenol produced similar time- and dose-dependent changes in cyclic AMP content and positive and negative dP/dt in isolated perfused working hearts obtained from 3 and 100 to 120 day control and diabetic rats. However, isoproterenol caused a significantly greater activation of phosphorylase enzyme in hearts isolated from 3 and 100 to 120 day diabetic rats as compared to age-matched controls. Diabetic rat hearts had a significantly higher total phosphorylase activity at 100 to 120 days as compared to age-matched controls. Prostaglandin E₁, a drug which increases cyclic AMP content without altering phosphorylase a activity in perfused rat hearts, increased phosphorylase a activity in acute as well as chronic diabetic rat hearts but not in control rat hearts. Cholinergic muscarinic receptors in the ventricles obtained from 180-day control and STZ diabetic rats were studied by performing radioligand binding studies. [³H]NMS was used as a radioligand to stereospecifically label all of the muscarinic receptor binding sites present in the ventricular membrane preparation. There was no change in either the receptor density or in the binding constants for antagonists and agonists at the muscarinic receptor site in 180-day diabetic rat hearts as compared to control. Ventricular noradrenaline content was estimated using an HPLC method, in 180-day alloxan and STZ diabetic and age-matched control rat hearts. There was no significant change in the noradrenaline content of diabetic rat hearts. Results obtained in the above studies demonstrate that various functional, pharmacological and biochemical alterations occur in the heart in experimental diabetes. Depressed cardiac performance was observed in isolated perfused diabetic rat hearts at various time points after the induction of diabetes and may represent the preclinical ventricular dysfunction phase of a developing diabetic cardiomyopathy. Changes noticed in the sensitivity of the.diabetic myocardium towards the negative inotropic effect of carbachol may represent various stages of a parasympathetic autonomic neuropathy of the heart in diabetes. The unaltered positive inotropic effect of Hsoproterenol and unchanged noradrenaline content in diabetic rat hearts indicate the absence of a sympathetic autonomic neuropathy. The depressed cardiac relaxant effect (maximum changes produced in negative dP/dt) of isoproterenol in diabetic rat hearts suggest defects in cardiac muscle relaxation, Ca²⁺ handling by the sarcoplasmic reticulum and perhaps ATP production and utilization. The enhanced sensitivity of the phosphorylase enzyme to agonists in diabetic rat hearts may be an outcome of alterations in Ca²⁺ homeostasis and other acute metabolic derangements in the heart caused by diabetes. All these changes could contribute to the pathogenesis of a diabetic cardiomyopathy. / Pharmaceutical Sciences, Faculty of / Graduate

Diabetic individuals have been found to have consistently higher levels of a minor hemoglobin component, HbAIc, than non-diabetic individuals. Previous investigators have suggested that variation in these high levels of HbAIc may be a reflection of the degree of diabetic hyperglycemia, of hypertriglyceridemia in diabetes, and of diabetic control. To date, evaluation of HbAIc as a clinically useful parameter has been hampered by the complexity of the method of measurement, the inconsistency in ranges of normal values reported, and the lack of a broad data base for comparison with new results. This investigation began with a critical appraisal of the methods currently in use for measurement of HbAIc, followed by a simplification and standardization of theJ assay. Then the levels of HbAIc in 16 non-diabetics and 47 diabetics were determined and the mean values for these 2 groups compared. The relationships between HbAIc levels in the diabetics and selected clinical data |fasting blood sugar, 24-hour urinary sugar, age,duration of illness, dietary record, insulin dosage, and family history of diabetes) were examined. Finally, the degree of diabetic control in each of the diabetic patients was estimated by the attending physician on a scale of 1 to 5 (1=very good, 2=good, 3=fair, 4=poor, 5=very poor) and was compared with the HbAIc measurement. Results of the investigation have shown that the chromatographic measurement of HbAIc is unusually sensitive to the pH of developers used and also somewhat variable with respect to the length of storage time and the optical density at which samples are read. The comparison of mean values of HbAIc for diabetics and non-diabetics has confirmed the approximately twofold higher concentration of HbAIc in diabetics. Significant correlations were found between HbAIc and fasting blood sugar (r = .442), fat content of diet (r=-. 300) , family history of diabetes (r=-.312) and degree of diabetic control (r=.529). Thus, HbAIc values tend to be higher in patients whose fasting blood sugar is high, whose diet contains relatively little fat, whose relatives are diabetic and /or whose diabetic control is poor. Correlations between HbAIc and duration of diabetes, HbAIc and insulin dosage or HbAIc and 24-hour urinary sugar were not statistically significant (r=-.131, r=-.264, r=„067, respectively). The HbAIc level appears to be an accurate reflection of fasting blood sugar levels averaged over a prolonged period of time (r=.587). In conclusion, HbAIc levels were found to provide an objective measure of diabetic control. The improved assay method makes it a practical and valuable tool for the clinician as well as the investigator. Measurement of HbAIc levels in diabetics presents a considerable advantage over currently available measures of diabetic control in assessing the long-term effectiveness of diabetic management. / Land and Food Systems, Faculty of / Graduate