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S Dai

Publications and source records attributed to S Dai.

At least 91 records · Page 5Linked to original sources
PubMed1995

Fructose-induced hypertension in rats is concentration- and duration-dependent.

The present study determined the most suitable concentration and duration of fructose treatment for inducing hypertension in Wistar rats. The correlation between fructose-induced hypertension and hyperinsulinemia was also evaluated. The rats were treated with 5%, 10%, or 20% fructose in drinking water. The greatest changes, including increases in blood pressure, fluid intake, and plasma levels of insulin, glucose, and triglycerides, and a decrease in food intake following fructose treatment, were observed with the 10% solution. The times of the onset and maximum response differed for the various parameters measured. The increase in blood pressure occurred earlier than the increase in the plasma insulin level. All abnormalities disappeared rapidly after fructose withdrawal. There was no significant correlation between plasma insulin level and systolic blood pressure. In conclusion, treatment with 10% fructose in drinking water (equivalent to a diet containing 48-57% fructose) for one week or longer is appropriate for the rapid production of fructose-induced hypertension in Wistar rats, which is associated with elevated levels of plasma insulin, glucose, and triglycerides.

Animals↗
PubMed1995

Lack of haematological effect of oral vanadium treatment in rats.

Haematological effects of oral administration of ammonium metavanadate 0.19 mmol V/kg/day, vanadyl sulphate 0.15 mmol V/kg/day, and bis(maltolato)oxovanadium (i.v.) 0.18 mmol V/kg/day in drinking water for 12 weeks were investigated in Wistar rats. Some selected haematological indices of the peripheral blood, including haematocrit, haemoglobin, erythrocyte count, reticulocyte percentage, leukocyte count and its differential count, platelet count, and osmotic fragility of the erythrocyte were determined using the standard methods. It was found that, throughout the 12-week experimental period, there were no significant differences between the untreated controls and various groups of vanadium-treated rats in all of the parameters measured. It is thus concluded that ammonium metavanadate, vanadyl sulphate, and bis(maltolato) oxovanadium (i.v.), at least at the doses and at the duration of treatment employed, do not produce significant haematological toxicity in rats.

Administration, Oral↗
PubMed1995

[Inhibition of glutamate uptake in rat brain synaptosome by pyrethroids].

In vitro studies showed deltamethrin (1 x 10(-7)-1 x 10(-4) mol/L) could inhibit 3H-DL-glutamate uptake in rat cerebral cortex and hippocampus synaptosome by 7.2%-21.5% and 10.4%-25.1%, respectively, with a dose-response pattern. But only in high-dose permethrin (1 x 10(-4) mol/L) can significantly reduce 3H-DL-glutamate uptake in rat hippocampus synaptosome. In addition, deltamethrin also can reduce 3H-DL-glutamate uptake in cerebellum and striatum of rats by 16.5% and 31.8%, respectively. It is suggested that both deltamethrin and permethrin, especially the former, can disturb the function of brain tissue in high-affinity-glutamate uptake with their alpha-cyano-group. So pyrethroids could play an important role in cerebral stimulation in mammals.

Animals↗
PubMed1995

[Predictive value of urinary calcium measurement on occurrence of pregnancy-induced hypertension].

OBJECTIVE: To study the predictive value of urinary calcium excretion on occurrence of pregnancy-induced hypertension (PIH). METHODS: Twenty-four-hour urinary calcium excretion, urinary calcium concentration and urinary calcium/creatinine (Ca/Cr) ratio were determined in 184 normal pregnant women and 30 patients with PIH. RESULTS: Twenty-four-hour urinary calcium excretion, urinary calcium concentration, and Ca/Cr ratio in PIH group were significantly lower than that in normal pregnant group (P < 0.01). 3 mmol/L of urinary calcium concentration and 0.04 of Ca/Cr ratio were chosen as predictive thresholds for development of PIH, with sensitivity of 76.2%, 81.0% and specificity of 97.5%, 98.2% respectively. CONCLUSIONS: Low urinary calcium excretion is a valuable marker for prediction of PIH.

Adult↗
PubMed1995

Laser Raman spectrometry study on experimental galactose-induced cataract.

PURPOSE: To observe the dynamic changes of hydration in galactose induced cataract. METHODS: Two groups of Wistar rats were used in the experiment. There were 12 rats in the experimental group, which were fed diet of 50% D-Galactose standard feed; while the control group had 8 rats fed standard feed. Their other living conditions were the same. At desired time periods, two Wistar rats fed galactose and one normal control were selected and killed 20 minutes before the instrument examination respectively, then, their lenses were removed from the orbs by a posterior approach. The cleaned fresh lens was placed in a quartz cuvette with Tris buffered balanced salt solution containing 5.5 mmol/L glucose. The quartz cuvette was placed on the stage of the Spectrometer. The laser beam was focused at the lens nuclear from the bottom of the cuvette and the scattered light was collected at 90 degrees to the incident beam. RESULTS: Raman spectroscopy showed that (1) during the formation of galactose cataract, the water signal (at 3390cm-1) increased obviously, and the ratio of I3390/I2935 increased from 0.31 (3 days) to 2.26 (17 days), which is correlated with the imbibition of water in the lens nuclear; (2) the hydration of lens nuclear could be divided into two phases. The ratio I3390/I2935 was increased slowly and steadily by 11 days after galactose feeding. Then, the ratio turned to increase quite fast till 17 days. CONCLUSION: The hydration of nuclear is changed simultaneously with the formation of cataract. The hydration of nuclear is mainly due to the imbalance of Na+/K+.

Animals↗
PubMed1994

Toxicity studies on one-year treatment of non-diabetic and streptozotocin-diabetic rats with vanadyl sulphate.

Streptozotocin-diabetic and non-diabetic rats were given vanadyl sulphate in drinking water at concentrations of 0.5-1.5 mg/ml for one year. It was found that vanadyl treatment did not produce persistent changes in plasma aspartate aminotransferase, alanine aminotransferase, and urea, specific morphological abnormalities in the brain, thymus, heart, lung, liver, spleen, pancreas, kidney, adrenal, or testis, or abnormal organ weight/body weight ratio for these organs in either non-diabetic or diabetic animals. Treatment significantly reduced the incidence of the occurrence of urinary stones in non-diabetic rats. In diabetic animals vanadyl treatment significantly reduced the mortality rate and prevented the elevation of plasma levels of alanine aminotransferase and urea, the increases in organ size, and the occurrence of megacolon but did not affect the development of renal and testicular tumours. Plasma and tissue concentrations of vanadium were determined and found to have the following order of distribution: bone > kidney > testis > liver > pancreas > plasma > brain. Vanadium was retained in these organs at 16 weeks following vanadyl withdrawal while the plasma levels were beneath detection limits. It is concluded that vanadyl sulphate at antidiabetic doses is not significantly toxic to rats following a one-year administration in drinking water, but vanadium may be retained in various organs for months after cessation of treatment.

Administration, Oral↗
PubMed1994

One-year treatment of streptozotocin-induced diabetic rats with vanadyl sulphate.

Streptozotocin-diabetic and non-diabetic rats were given various concentrations of vanadyl sulphate in drinking water for one year. It was found that vanadyl sulphate caused significant decreases in body weight gain and plasma insulin level in non-diabetic rats, but did not significantly alter fluid and food intakes or plasma levels of glucose, triglycerides, or cholesterol. In diabetic animals, vanadyl treatment significantly alleviated or prevented the occurrence of hyperglycaemia, hypoinsulinaemia, hyperphagia, polydipsia, hyperlipidaemia, or cataract formation, but the slower body weight gain was not improved. There were gradual decreases in the intake of the compound required to correct hyperglycaemia in the values of ED50 with age of the rats. The beneficial effects of vanadyl treatment persisted 16 weeks following the withdrawal of the compound. It is concluded that vanadyl sulphate is an effective agent for chronic therapy of streptozotocin-induced diabetes in rats, and its prolonged use does not lead to the development of tolerance.

Administration, Oral↗
PubMed1994

One-year treatment of non-diabetic and streptozotocin-diabetic rats with vanadyl sulphate did not alter blood pressure or haematological indices.

Circulatory and haematological effects of chronic administration of vanadyl sulphate in drinking water for one year in non-diabetic and streptozotocin-diabetic rats were investigated. At various time points during the treatment period and at 13 weeks following its withdrawal, systolic blood pressure and pulse rate were measured using a tail-cuff method and some selected haematological indices, including haematocrit, haemoglobin, erythrocyte count, reticulocyte percentage, leukocyte count, platelet count, and leukocyte composition of the peripheral blood were determined using standard methods. It was found that prolonged treatment of either nondiabetic or streptozotocin-diabetic rats with vanadyl sulphate did not cause significant changes in the parameters observed but significantly alleviated the occurrence of bradycardia and the decreased leukocyte count in the peripheral blood in streptozotocin-diabetic animals. No significant changes in systolic blood pressure, pulse rate, or haematological indices were observed following the withdrawal of vanadyl sulphate, except that the previously vanadyl-treated diabetic rats were found to have higher leukocyte count, platelet count and neutrophil percentage, and lower lymphocyte percentage in their leukocyte composition. It is concluded that vanadyl sulphate does not have a hypertensive effect nor is it significantly toxic to the haemopoietic system in rats.

Administration, Oral↗
PubMed1994

Fructose loading induces cardiovascular and metabolic changes in nondiabetic and diabetic rats.

The effects of fructose loading on the integrated cardiovascular function in vivo, glycemic control, glucose tolerance, and plasma lipid levels in nondiabetic and streptozotocin (STZ) diabetic rats were investigated. Endothelial morphology of the thoracic aorta was also assessed with scanning electron microscopy. Fructose-loaded nondiabetic rats exhibited elevated blood pressure and pulse rate, and signs of arterial atherogenesis, such as focal adherence of leukocytes and fibrin to the endothelium. Intraperitoneal glucose tolerance tests revealed a greater increase in plasma insulin in response to glucose challenge in these animals than in the control. Compared with the untreated STZ-diabetic animals, fructose-loaded diabetic rats had significantly greater hyperglycemia, glucose intolerance, and hyperlipidemia and higher blood pressure, but had a similar degree of hypoinsulinemia, cardiac dysfunction, and cardiac enlargement. They also showed signs of early atherogenesis. The central venous pressure and the susceptibilities of the rats to the induction of ventricular arrhythmias by intravenous infusion of aconitine were not significantly affected by either STZ injection or fructose loading. It is concluded that prolonged intake of an excessive amount of fructose has detrimental effects on the cardiovascular system, glucose metabolism, and plasma lipid levels in both nondiabetic and STZ-diabetic rats.

Angiotensin II↗
PubMed1994

meta-iodobenzylguanidine uptake in the hypertensive-diabetic rat heart: a marker for myocardial dysfunction?

The purpose of this study was to investigate the cardiac adrenergic neuronal changes induced by diabetes and hypertension by using an analogue of norepinephrine, meta-iodobenzylguanidine (MIBG), and to compare these changes with the contractile state of ventricular papillary muscle. The tissue concentration of norepinephrine in the cardiac apex was also measured for direct comparison with [123I]MIBG uptake. One week following the induction of diabetes by streptozotocin injection (55 mg/kg, i.v.), male Sprague-Dawley rats were given subcutaneous injections of a hypertension-inducing agent, deoxycorticosterone acetate (DOCA, 25 mg/kg), or DOCA vehicle twice weekly for 3, 6, 9, or 12 weeks. At the end of each time point, the animals were injected intravenously (15 mCi/mg; 1 Ci = 37 GBq) with [123I]MIBG. The results showed a progressive decrease in MIBG uptake into the hearts of diabetic, hypertensive, and diabetic-hypertensive rats during the 12-week observation period, compared with the control group. However, length-tension papillary muscle studies at 12 weeks indicated that only the diabetic group had a diminished performance compared with control. Furthermore, an inverse relationship was observed between MIBG uptake and norepinephrine levels in the cardiac apex of the diabetic and diabetic-hypertensive groups. Therefore, we concluded that either MIBG does not provide an accurate indication of adrenergic integrity or that there is no relationship between sympathetic activity and myocardial function at the time points measured. MIBG did not prove to be a useful marker for myocardial dysfunction in diabetic rats.

3-Iodobenzylguanidine↗
PubMed1994

Improvement in cardiac function in streptozotocin-diabetic rats by salt loading.

Effects of salt loading by drinking 0.9% NaCl solution on the myocardial performance in nondiabetic and diabetic Wistar rats were studied using the isolated working heart apparatus. Body weight and fluid and food intakes of these animals were monitored. Blood pressure and plasma levels of glucose, insulin, cholesterol, and triglycerides were also measured. Diabetes was induced by intravenous injection of streptozotocin (60 mg/kg). Diabetic rats were found to develop myocardial dysfunction at 8 weeks after STZ injection, accompanied by significant increases in food and fluid intakes, slowed body weight gain, hyperglycemia, hypoinsulinemia, and hyperlipidemia but without significant changes in blood pressure. Salt loading did not cause significant changes in any of the parameters studied in nondiabetic rats. However, in streptozotocin-diabetic rats given saline to drink, the impaired myocardial function was significantly improved and was associated with a significant reduction in hyperphagia and hyperlipidemia. Plasma glucose levels significantly decreased at weeks 1-3 but increased to the levels of untreated diabetic animals at weeks 4-7. There was an increase in fluid intake, but neither blood pressure nor plasma insulin levels were significantly affected. It is suggested that the improvements in cardiac function and hyperlipidemia in diabetic rats by salt loading may be related to each other; however, the mechanisms for these effects are not clear but are unlikely to be due to changes in glycemic control.

Animals↗
PubMed1994

Integrated cardiovascular function in the conscious streptozotocin-diabetic deoxycorticosterone-acetate-hypertensive rats.

Blood pressure, heart rate, and left ventricular function were measured in conscious diabetic Sprague-Dawley rats subjected to 5 weeks of deoxycorticosterone acetate (DOCA) treatment which was started 1 week following intravenous injection of streptozotocin (STZ) (60 mg/kg) to induce diabetes mellitus. It was found that chronic administration of DOCA in nondiabetic animals caused an increase in blood pressure and functional parameters of left ventricle, and a decrease in heart rate and plasma insulin levels. Normotensive diabetic rats exhibited hyperglycemia, hypoinsulinemia, and a lower body weight as compared with control animals but did not show significant abnormalities in cardiovascular function. DOCA-hypertensive STZ-diabetic rats had similar hyperglycemia, milder hypoinsulinemia, and a significantly lower rate of left ventricular relaxation and systolic blood pressure compared with the nondiabetic DOCA-hypertensive animals. It is concluded that the addition of DOCA hypertension to intact 6-week STZ-diabetic Sprague-Dawley rats results in the occurrence of cardiac dysfunction.

Animals↗
PubMed1994

Neuroimaging and neuropathologic findings in AIDS patient with cytomegalovirus infection.

This 21-year-old male with hemophilia A developed cytomegalovirus (CMV) retinitis associated with acquired immunodeficiency syndrome (AIDS). He had a history of numerous blood transfusions. Serum antibody titers became positive for human immunodeficiency virus (HIV), when the patient was 18 years of age. Three years later, he developed CMV retinitis due to his immunosuppression. Ganciclovir (DENOSINE, TANABE SEIYAKU CO., LTD., Osaka, Japan) therapy given for 4 weeks produced a marked improvement in the ocular fundal findings, but the neurologic signs and symptoms, including headache, hypoesthesia, disorientation, and dementia became worse. T2-weighted magnetic resonance imaging (MRI) demonstrated a diffuse high intensity area in the periventricular white matter and small focal or patchy lesions in the hippocampus, basal ganglia, midbrain, medulla oblongata and the nucleus dentatus. The patient died of HIV encephalopathy and CMV infection. Characteristic CMV intranuclear inclusion bodies were observed histologically in most sites of the brain including the hippocampus, white matter, basal ganglia, midbrain, medulla oblongata, nucleus dentatus and the retina. Infiltration by monocyte-macrophage and multinucleated giant cells, which are characteristic of HIV encephalopathy, were observed in the periventricular white matter and the hippocampus. In this patient, the neuroimaging findings were compatible with the neuropathologic observations. MR imaging proved useful in detecting the central nervous system (CNS) lesions of AIDS and CMV infection.

AIDS Dementia Complex↗
PubMed1994

[Clinical application of rhombotrapezious island musculocutaneous flap for skull base and/or craniomaxillary operation with malignant tumor].

Regional pedicled musculocutaneous flaps are the mainstay of the head and neck reconstruction. They provide a rapid, highly reliable and single-staged technique that is applicable in most cases. The rhombotrapezious island musculocutaneous flap is valuable in the base and craniomaxilloface reconstruction. In this study we updated our experience with the rhombotrapezious island musculocutaneous flap (RTIMF) in 6 cases from 1989 to 1993. Dissections were performed on 9 cadavers, 4 preserved and 5 fresh, yielding 18 pairs or dorsal scapular and transverse cervical artery for evaluation. In the five fresh cadavers, the arteries were selectively cannulated and injected with colored latex. 67% with dorsal scapular and transverse cervical artery commonly arose from the thyro-cervical trunk. 33% with the dorsal scapular artery directly arose from the second part of the subclavian artery. In the period of 1989-1993, 6 rhombotrapezious island musculocutaneous flaps with vascularized pedicle were used for immediate repair in the skull base or craniomaxillary cancer operations. There was no complication of the flaps. Donor site complications were relatively minor. The disturbance in shoulder function was well tolerated. We advocated the incorporation of both the greater and lesser rhomboid muscle to form the compound rhombotrapezious flaps to enhance the vascular supply to the overlying skin. The major advantage of the RTIMF are that it provides a long paddle of thin pliant, hairless skin and muscle that can be rotated as far as the craniomaxilloface and scalp in a single stage. It offers the longest arc of rotation and thus the greatest versatility for the skull base or craniomaxillary reconstruction.

Adult↗
PubMed1994

Cardiovascular and metabolic changes in spontaneously hypertensive rats following streptozotocin administration.

OBJECTIVES: To investigate whether the high mortality rate that occurs in streptozotocin (STZ)-diabetic spontaneously hypertensive rats (SHR) is related to abnormalities in glycemic control, in hemodynamics and cardiac function, or in susceptibility to the occurrence of ventricular arrhythmias. METHODS: Diabetes was induced in SHR and Wistar-Kyoto (WKY) rats by the intravenous injection of STZ 55 mg/kg. Intraperitoneal glucose tolerance tests were performed after six and 11 weeks. Blood pressure was measured in conscious rats at weeks 0 and 11 with a tail-cuff method and in anesthetized animals at week 12 through a cannulated artery. Response of myocardial function to rapid intravenous infusion of saline 10 mL/kg/min and the times of onset of ventricular arrhythmias during intravenous infusion of aconitine 20 micrograms/kg/min were determined in anesthetized rats at week 12. Plasma samples from the rats were assayed for glucose, insulin, triglycerides and carnitine. RESULTS: STZ injection caused hyperglycemia, hypoinsulinemia and glucose intolerance equally in SHR and WKY. Diabetic SHR exhibited significant hypertriglyceridemia, depletion in plasma carnitine, impaired responses of blood pressure and myocardial function to rapid intravenous infusion of saline and a 37.5% mortality rate, whereas diabetic WKY did not exhibit these changes. SHR and WKY, diabetic or nondiabetic, were equally sensitive to the induction of ventricular arrhythmias by aconitine infusion. CONCLUSION: Mortality of the STZ-diabetic SHR is not due to an exaggeration of the impaired glycemic control, but may be attributed to the occurrence of cardiac dysfunction. The development of life-threatening cardiac arrhythmias, while unlikely, cannot be completely excluded.

Aconitine↗
PubMed1993

[Effect of occupation on health behavior and biological cardiovascular risk factors].

Within the framework of the second survey of MONICA-Switzerland (cantons of Vaud and Fribourg; canton of Tessin), the data of 683 working men were analysed to examine the relation between occupation and cardiovascular risk factors. For this purpose, lifestyle factors (smoking, nutritional habits, physical activity, alcohol intake) as well as blood pressure and serum lipoprotein concentrations were compared among 17 different occupational groups. Furthermore, every occupational group was ranked, based on the medians of the mentioned dependent variables. A strong relationship between socioeconomic status (recorded as number of years of schooling completed) and an index for healthy lifestyle was found. However, in some occupational groups a major discrepancy between socioeconomic status respectively lifestyle and measured cardiovascular risk factors (blood pressure, lipoprotein concentrations) was observed. It is therefore hypothesized that unknown occupational factors adversely affect blood pressure and serum lipoproteins for example in physicians, managers and executives whereas the contrary--beneficial effect of unknown occupational factors--is true for example for drivers and bricklayers.

Adult↗
PubMed1993

Hemodynamic and nonhemodynamic mechanism of experimental pulmonary edema in rats and the effect of anisodamine and tetramethylpyrazine--electron microscopic observation and measurement of pulmonary arterial, pulmonary arterial wedge and systemic arterial pressure (Part 2).

The pulmonary edema (PE) induced by adrenaline (AD) administration is similar to neurogenic PE. Anisodamine (ADM, 654-2, 30 mg/kg) and tetramethylpyrazine (TMP, 120 mg/kg) have shown significant preventive effects. Electron microscopic observation was carried out to study the changes of microvascular permeability, and the dynamic change of mean pulmonary arterial pressure (PAP, 40 rats), mean pulmonary arterial wedge pressure (PAWP, 20 rats) and mean carotid arterial pressure (CAP) were also measured. The results suggested that both ADM and TMP have significant inhibitory effects on PAWP and CAP increase, as well as on the damage responsible for the increase of microvascular and alveolar permeability.

Adrenergic alpha-Agonists↗