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1.
Journal of biomedical science ; 13(5): 675-680, September 2006. ilus, tab
Artigo em Inglês | MedCarib | ID: med-17810

RESUMO

Retrograde transport of Wheat germ agglutinin conjugated to Horseradish peroxidase (WGA-HRP) was used in labeling vagal neurons projecting to the stomach from the dorsal motor nucleus of the vagus nerve (DMNV) in Streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in the experimental rats by intraperitoneal injection of buffered STZ. Control rats were injected with an equivalent volume of the citrate buffer not containing STZ.The experimental rats, which became diabetic about 24 h after intraperitoneal injection of STZ, were kept alive for a period of 24 weeks to attain a chronic state of diabetes. Control euglycaemic rats were also kept alive for 24 weeks. At the end of 24 weeks, the two groups of rats were prepared for stomach surgery. Following anaesthesia laparotomy was performed and the stomach exteriorized. The anterior and posterior walls of the stomach were injected with 0.1 ml of 5 percent WGA-HRP in 0.5 M sodium chloride. Experimental and control rats were sacrificed 48–72 h after tracer injection by transcardial perfusion with normal saline, fixative and buffered sucrose.Transverse serial frozen sections of the brainstem were processed for WGA-HRP neurohistochemistry and analyzed under light and dark-field microscopy. The analyses of the sections taken from the chronic diabetic rats revealed fewer WGA-HRP labeled neurons in the DMNV than sections taken from the control euglycaemic rats. The depletion of labeled neurons in the diabetic rats compared with the euglycaemic rats is indicative of an interference with the mechanism of retrograde neuronal transport of WGA-HRP by chronic diabetic state.


Assuntos
Ratos , Diabetes Mellitus Experimental , Estômago , Conjugado Aglutinina do Germe de Trigo-Peroxidase do Rábano Silvestre , Nervo Vago
2.
West Indian Veterinary Journal ; 5(1): 19-22, November 2005. ilus
Artigo em Inglês | MedCarib | ID: med-17844

RESUMO

The L-cells of the small intestine synthesize a proglucagon molecule which is processed to form glicentin, oxyntomodulin, glucagon-like peptide 1 (GLP-1) and glucagons-like peptide 2 (GLP-2). Glicentin and oxyntomodulin inhibit gastric secretion, and delay tansit time through the stomach. Serum concentrations of GLP-1 and GLP-2 have been reported to vary in types 1 and 2 diabetes and in streptozocin induced diabetic rats. It was initially thought that these variations were due to the activity of intestinal L- cells, but it was later found that this was from pancreatic alpha cells. Very little work had been done on the effect of diabetes on glicentin producing cells of the gut. In this experiment the effects of alloxan diabetes on glicentin producing L-cells of the intestines was investigated using immunohistochemical techniques. Results showed that the immunoreactivity of glicentin was noticeablly reduced in the L-cells of the small intestine of alloxan-diabetic rats.


Assuntos
Ratos , Diabetes Mellitus Experimental , Intestino Delgado
3.
West Indian veterinary journal ; 5(1): 19-22, November 2005. ilus
Artigo em Inglês | MedCarib | ID: med-18172

RESUMO

The L-cells of the small intestine synthesize a proglucagon molecule which is processed to form glicentin, oxyntomodulin, glucagon-like peptide 1 (GLP-1) and glucagons-like peptide 2 (GLP-2). Glicentin and oxyntomodulin inhibit gastric secretion, and delay tansit time through the stomach. Serum concentrations of GLP-1 and GLP-2 have been reported to vary in types 1 and 2 diabetes and in streptozocin induced diabetic rats. It was initially thought that these variations were due to the activity of intestinal L- cells, but it was later found that this was from pancreatic alpha cells. Very little work had been done on the effect of diabetes on glicentin producing cells of the gut. In this experiment the effects of alloxan diabetes on glicentin producing L-cells of the intestines was investigated using immunohistochemical techniques. Results showed that the immunoreactivity of glicentin was noticeablly reduced in the L-cells of the small intestine of alloxan-diabetic rats.


Assuntos
Ratos , Diabetes Mellitus Experimental , Intestino Delgado
4.
In. University of the West Indies, Mona, Jamaica. Faculty of Medical Sciences. Eighth Annual Research Conference 1999. Kingston, s.n, 1999. p.1. (Annual Research Conference 1999, 8).
Monografia em Inglês | MedCarib | ID: med-1445

RESUMO

INTRODUCTION: This study was designed to look at ATP sensitive potassium channels (KATP-sc) in diabetic male Sprague-Dawley rat hearts. Diabetes mellitus was induced using streptozocin (ip). KATP-SC can be found in pancreatic B-cells, cardiac muscle, skeletal muscle, neurones, hypothalamus and smooth muscle. Cromakalim and adenosine were used to construct concentration-response curves. These drugs are KATP-SC openers that cause shortening of action potential duration and hyperpolarisation. This is a novel study as there is a sparsity of information on the effect of KATP-SC openers on the hearts of diabetic animals. We therefore hypothesised that cromakalim and adenosine may have both an effect on the electrical activity as well as the contractility in the diabetic myocardium. METHODS: Male Sprague-Dawley rats (150-250 gm) were treated with streptozotocin (STZ) (60 mg/Kg i.p.). All animals were kept under identical living conditions and allowed free access to food and water for 1 week. Animals were then sacrificed after being anaesthetised with 60 mg/Kg pentobarbital containing 1000 Units/ml heparin. Hearts were being rapidly excised, placed in 4 degrees C. Krebs-Henseleit buffer and mounted in a Langendorff system. Concentration-response curves were constructed for cromakalim (0.01nM-0.1uM), and adenosine (0.1uM-100uM). Parameters measured were heart rate (HR), P-R and QRS intervals, systolic pressure (SP), diastolic pressure (DP) and developed pressure (Dev. Pre.). RESULTS: The results found for cromakalim in diabetic rats and adenosine in normal rats mirrored what has been found in previous studies for these drugs in non-diabetic animals, namely, a decrease in HR, an increase in P-R and QRS and a decrease in SP and Dev. Pre. However, adenosine in diabetic rats showed some unexpected results such as a decrease in P-R, and an increase in SP and Dev. Pre. It is possible that the diabetic state interferes significantly with the actions of adenosine but not as significantly with those of cromakalim. Conclusion: The results indicate that adenosine may not be cardioprotective in diabetic animals. This conclusion may be drawn from the fact that P-R interval decreased with increasing concentrations of adenosine. This may lead to the production of arrhythmias such as life threatening ventricular tachycardia or fibrillation (AU)


Assuntos
Ratos , Masculino , 21003 , Diabetes Mellitus Experimental , Canais de Potássio/efeitos dos fármacos , Cromakalim/uso terapêutico , Adenosina , Fibrilação Ventricular/etiologia , /diagnóstico
5.
In. University of the West Indies, Mona, Jamaica. Faculty of Medical Sciences. Eighth Annual Research Conference 1999. Kingston, s.n, 1999. p.1. (Annual Research Conference 1999, 8).
Monografia em Inglês | MedCarib | ID: med-1446

RESUMO

Neem (Azadirachta indica) products have been extensively used in Ayurvedic medicine in India for many centuries. To elucidate a common folkloric saying, "two leaves a day keeps diabetes away", thirty male Wistar rats weighing between 180 to 250 g were randomly assigned to three equal groups. To induce diabetes, rats in groups II and III received a single intraperitoneal dose of Streptozotocin (STZ) at a rate of 50 mg/Kg body weight. After 5 days of STZ treatment, diabetic rats in group III received 0.4 percent aqueous neem extract in drinking water for 188 days. Rats in group III received citrate buffer and served as drinking water for 188 days. Rats in group I received citrate buffer and served as control. All the rats were maintained under standard management conditions and received water/extract and dry pellet diet ad libitum. The animals were sacrificed after 290 days for histological examination of various tissues. The results of the study revealed that (1) the mean blood glucose levels showed a decreasing trend (p>0.05) during 48-77 days of neem treatment and also after 51 days of discontinuation of the neem treatment (2) the percent gain in body weight in neem treated diabetic rats was lower than in diabetic rats (20v/s 80 percent) (p value). In conclusion, the aqueous extract of neem showed significant improvements in the body weights and lessened mortality in STZ induced diabetic rats but could not normalise blood glucose levels.(AU)


Assuntos
Ratos , 21003 , Azadirachta/uso terapêutico , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus Experimental/tratamento farmacológico , Glicemia/efeitos dos fármacos
6.
West Indian med. j ; 47(suppl. 1): 31, Mar. 5-8, 1998.
Artigo em Inglês | MedCarib | ID: med-1549

RESUMO

Yams and dasheen are widely produced in the caribbean where they grow readily. They are important sources of carbohydrates and vitamins. They were basically traditional foods of the people of Africa and the Caribbean until the introduction of `western diets'. It has been insinuated that this shift has led to the increase in cardiovascular diseases and diabetes. This study aims at examining the effects of organic extracts of yams and dasheen on diabetic rats in the light of the fact that they have been shown to contain linamarin in low quantities. Linamarin, a cyanoglucoside, is suspected to be involved in the aggravation of diabetes mellitus. A study was conducted on the lipid metabolism of the streptozotocin-induced diabetic rats fed supplements of organic extracts of yam and dasheen for four weeks. The levels of blood glucose and lipids were determined. Lipid metabolism and transaminase activities in the liver were assessed. The diabetic rats and the groups fed extracts of yam, dasheen and linamarin supplements lost weight significantly despite the non-significantly difference in their food intake. Liver weights were significantly (p<0.05> reduced in these groups compared to the healthy control rats fed a similar diet without the appropriate supplements (p<0.05>. The groups fed yam and dasheen extracts had significantly lower liver weights when compared to the diabetic group fed regular rat diet (p<0.05), and the diabetic group fed normal rat diet plus commercial linamarin additive (p<0.05). Rats fed dasheen organic extract supplement had significantly lower blood glucose levels (13.18 ñ 3.53 mmol/l) compared to the diabetic group fed normal rat diet (19.50 ñ 5.16 mmol/l) at p<0.05. Rats fed dasheen organic extract supplement had significantly lower blood triglyceride levels (2.29 ñ 0.16 mmol/l) with respect to the normal; 9.85 ñ 0.57 mmol; p<0.05, while yam extract (9.57 ñ 0.55 mmol/l) and linamarin (10.63 ñ 0.46 mmol/l) fed groups did not show significant changes in blood triglyceride levels. Blood total cholesterol level was reduced from 9.71 ñ 0.23 mmol/l in the diabetic state to 6.14 ñ 0.05 mmol/l and 6.66 ñ 0.65 mmol/l by feeding supplements of yam and dasheen extracts, respectively. The diabetic condition did not significantly affect the integrity of the liver as measured by alanine and asparate transaminase activities in this short term study.(AU)


Assuntos
Ratos , 21003 , Lipídeos/sangue , Lipídeos/metabolismo , Fígado/metabolismo , Diabetes Mellitus Experimental/metabolismo , Liliaceae/metabolismo
7.
West Indian med. j ; 45(2): 60-2, June 1996.
Artigo em Inglês | MedCarib | ID: med-3661

RESUMO

A 24-hour glycaemic profile following streptozotocin (80 mg/kg. ip) injection was investigated in fasted rats. The most prominent changes in blood glucose were hyperglycaemia associated with low levels of plasma insulin after two hours followed by hypoglycaemia associated with high levels of plasma insulin after six hours; subsequently hyperglycaemia progressively developed and this was associated with decreasing levels of plasma insulin. Further probing revealed that at two hours after streptozotocin injection, the pancreatic á-cells could not respond to an oral glucose load while, at six hours after, there was an apparent return of á-cell responsiveness, but subsequently á-cell responsiveness was progressively lost and histological examination revealed cellular damage. From these results, it is concluded that within six hours of injection, stretozotocin initiates pancreatic á-cell damage which leads to the development of diabetes mellitus. (AU)


Assuntos
21003 , Ratos , Estreptozocina/farmacologia , Ilhotas Pancreáticas/efeitos dos fármacos , Glicemia/efeitos dos fármacos , Diabetes Mellitus Experimental/sangue , Teste de Tolerância a Glucose , Insulina/metabolismo
8.
Jamaican Nurse ; 32(2): 25-30, 1994.
Artigo em Inglês | MedCarib | ID: med-3412

RESUMO

There is an ongoing search for new and effective medications for treating diabetes mellitus. To facilitate this search, experimental diabetes induced by agents such as streptozotocin is often used. However, features of the diabetic state produced by streptozotocin need to be clarified in order to define the parameters within which investigators can work with the diabetic model. This study was therefore done to determine the profile produced by streptozotocin in rats. Single intraperitoneal doses of streptozotocin 40, 60, 80 mg/kg were administered to approximately 10 week-old Wistar rats of both sexes. Blood glucose and other parameters were observed for one year. Ames Gluco-System was used for glucose monitoring. Streptozotocin dose range 60-80 mg/kg was effective in precipitating a persistent diabetic state with onset within 24 hours. However, there was no persistent change in weight. There were indications that there may be variable production of insulin. There may also be some reversibility of the diabetic state in some animals. Overall the findings indicated that the severity and persistence of the diabetes produced depended on the dose of streptozotocin and that the dose range 60-80 mg/kg may be suitable to produce experimental diabetes for laboratory study(AU)


Assuntos
21003 , Ratos , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus Experimental , Estreptozocina
9.
West Indian med. j ; 41(4): 146-9, Dec. 1992.
Artigo em Inglês | MedCarib | ID: med-15382

RESUMO

A diabetic state was induced with a single intraperitoneal dose (45 mg/kg) of streptozotocin in rats. Their fasting blood glucose concentrations oscillated between 12.7 ñ 1.9 mmol/l and 4.6 ñ 0.6 mmol/l during 35 days of monitoring. Their body weights were also reduced, while controls gained weight, although food consumption was not significantly different. Also, within the first «-hour of the oral glucose tolerance test, blood glucose concentration increased in the diabetic and the control rats, but only in the control rats was there a simultaneous increase in serus IRI concentration (7.2 ñ 8 x 10 to the 2nd power pmol/l to 27.0 ñ 5.2 x 10 to the 2nd power pmol/l) which, like the blood glucose concentration, subsequently fell to fasting level in the control rats. In the diabetic rats, however, it was not until the following hour of the tolerance test that serum IRI concentration increased (3.4 ñ 0.3 x 10 to the 2nd power pmol/l to 65.0 ñ 12.5 x 10 to the 2nd power pmol/l) and blood glucose concentration began to fall. By the end of the test in the diabetic rats, blood glucose concentration fell but remained significantly higher than the control value. Additionally, no pancreatic tumours were identified in these diabetic rats. The results therefore suggest that an unstable diabetic state was produced by streptozotocin because the treshold for insulin secretion by glucose was increased, while the production of insulin by the pancreas was not significantly affected (AU)


Assuntos
Ratos , 21003 , Diabetes Mellitus Experimental/induzido quimicamente , Glicemia/análise , Estreptozocina , Ratos Endogâmicos , Glicemia , Insulina/sangue
10.
West Indian med. j ; 37(2): 100-5, June 1988.
Artigo em Inglês | MedCarib | ID: med-11705

RESUMO

The extent of blood glucose increases produced by products of cassava and wheat flour were compared in experiments performed in cats and rats. In normal anaesthetized cats, a meal of 500 mg grated cassava preparation produced a mean maximum blood glucose increase which is 200 percent less than the mean maximum blood glucose increase produced by a meal of 500 mg wheat flour preparation. In diabetic rats, a 20 gm homogenous mixture, consisting of 50 percent cassava bammmy and 50 percent rat chow that was eaten within a 24-hour period, produced a mean blood glucose increase which is 221 percent less than the blood glucose increase produced by a 20gm homogenous mixture, consisting of 50 percent wheat flour bread and 50 percent rat chow and eaten over a similar period of time. The lower glycaemic reponses of the cassava preparations therefore represent significant advantages over wheat flour preparations, for its (cassava preparation) inclusion in the diet of the diabetic (AU)


Assuntos
21003 , Gatos , Ratos , Manihot , Diabetes Mellitus Experimental/dietoterapia , Dieta para Diabéticos , Plantas Comestíveis , Glicemia/análise , Triticum
11.
Clin Sci ; 33(3): 489-506, Dec. 1967.
Artigo em Inglês | MedCarib | ID: med-15824

RESUMO

Rats were infused intravenously for periods up to 7 hr with L-[U-14C]lysine. After about 4 hr the specific activity of free lysine in the blood reached a plateau. From the value of the plateau specific activity it is possible to calculate the total lysine flux into or out of the blood stream. In normal rats the flux is equivalent to a total protein turnover of 25-30 g kg-1 day-1. In male, but not in female rats the total flux decreased significantly with increasing body weight or age. Six weeks of protein depletion caused a decrease of 30 percent in the flux. Alloxan diabetes in a small number of rats caused no significant change. After the first « hr of the infusion the specific activity of the mixed serum proteins increased almost linearly. From the rate of increase and the specific activity of the free lysine at plateau, an approximate estimate can be made of the renewal rate of the serum proteins. This estimate must be too low, because the specific activity of the free amino acid at the site of synthesis, e.g. in the liver cell, must always be lower than in serum. The validity of the continuous infusion method is discussed in relation to other methods of measuring total amino acid or protein turnover.(AU)


Assuntos
Ratos , 21003 , Masculino , Feminino , Lisina/metabolismo , Proteínas Sanguíneas/metabolismo , Isótopos de Carbono , Diabetes Mellitus Experimental/metabolismo , Injeções Intravenosas , Cinética , Lisina/administração & dosagem , Lisina/sangue , Fatores Sexuais
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