Chaman Lal Kaul

Bio: Chaman Lal Kaul is an academic researcher. The author has contributed to research in topics: Thoracic aorta & Insulin resistance. The author has an hindex of 18, co-authored 28 publications receiving 2258 citations.

Reversal of glucose intolerance by by pioglitazone in high fat diet-fed rats.

Abstract: The present study was undertaken to determine the effect of pioglitazone (3, 10 and 30 mg/kg p.o.), an insulin sensitizer, on glucose intolerance in high fat diet- (HFD) fed rats (a nongenetic model of insulin resistance). In addition, the effect of pioglitazone (3, 10 and 30 mg/kg p.o.) on diet-induced changes in body weight, plasma glucose, insulin, triglyceride and total cholesterol levels were also determined. The feeding of HFD for 4 weeks produced a significant increase in body weight, total fat pad weight, basal/fasting plasma glucose, insulin, basal triglyceride (TG) and total cholesterol (TC) levels in male rats. Furthermore, the rats fed HFD exhibited fasting hyperglycemia and hyperinsulinemia as well as enhanced glycemic response to exogenously administered glucose (2 g/kg p.o.) during an oral glucose tolerance test (OGTT) at the end of 4 weeks of dietary manipulation, indicating that the rats had developed insulin resistance and glucose intolerance. Treatment with pioglitazone (10 and 30 mg/kg p.o.) once daily for 2 weeks significantly diminished the elevated basal plasma insulin and TG levels in HFD-fed rats. In addition, a statistically significant reduction in TC level was observed only with the high dose of pioglitazone (30 mg/kg p.o.). However, pioglitazone had no significant effect on body weight, total fat pad weight and basal plasma glucose level. Pioglitazone (10 and 30 mg/kg p.o.) significantly reduced fasting hyperglycemia and reversed oral glucose intolerance to normal in HFD-fed rats compared with control normal rats. The above findings suggest that pioglitazone has potent insulin-sensitizing and lipid-lowering properties in a HFD-fed rat model. In conclusion, the present study demonstrates that the adult male rats on a HFD for 4 weeks exhibited the characteristic features of obesity, insulin resistance and glucose intolerance, namely increased body weight, increased total fat pad weight, mild basal/fasting hyperglycemia, hyperinsulinemia, hypertriglyceridemia, hypercholesterolemia and impaired oral glucose tolerance, that closely resemble the human prediabetic obese insulin-resistant and glucose-intolerant state. Further treatment with pioglitazone once daily for 2 weeks significantly ameliorated changes in basal plasma insulin, TG and TC, and reversed oral glucose intolerance to normal in HFD-fed rats, suggesting its potential in the treatment of insulin resistance and glucose intolerance associated with abnormal lipid metabolism.

Neuroprotective efficacy and therapeutic time window of peroxynitrite decomposition catalysts in focal cerebral ischemia in rats

Abstract: Free radicals have been implicated in cerebral ischemia reperfusion (IR) injury. Massive production of nitric oxide and superoxide results in continuous formation of peroxynitrite even several hours after IR insult. This can produce DNA strand nicks, hydroxylation and/or nitration of cytosolic components of neuron, leading to neuronal death. Peroxynitrite decomposition catalysts 5,10,15,20-tetrakis(N-methyl-4'-pyridyl)porphyrinato iron (III) (FeTMPyP) and 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato iron (III) (FeTPPS) have been demonstrated to protect neurons in in vitro cultures; however, their neuroprotective efficacy in cerebral IR injury has not been explored. In the present study, we investigated the efficacy and the therapeutic time window of FeTMPyP and FeTPPS in focal cerebral ischemia (FCI). FCI was induced according to the middle cerebral artery occlusion (MCAO) method. After 2 h of MCAO and 70 h of reperfusion, the extent of neurological deficits, infarct and edema volume were measured in Sprague-Dawley rats. FeTMPyP and FeTPPS were administered at different time points 2, 6, 9 and 12 h post MCAO. FeTMPyP and FeTPPS (3 mg kg(-1), i.v.) treatment at 2 and 6 h post MCAO produced significant reduction in infarct volume, edema volume and neurological deficits. However, treatment at latter time points did not produce significant neuroprotection. Significant reduction of peroxynitrite in blood and nitrotyrosine in brain sections was observed on FeTMPyP and FeTPPS treatment. As delayed treatment of FeTMPyP and FeTPPS produced neuroprotection, we tested whether treatment had any influence over the apoptotic neuronal death. DNA fragmentation and in situ nick end-labeling assays showed that FeTMPyP and FeTPPS treatment reduced IR injury-induced DNA fragmentation. In conclusion, peroxynitrite decomposition catalysts (FeTMPyP and FeTPPS) produced prominent neuroprotection even if administered 6 h post MCAO and the neuroprotective effect is at least in part due to the reduction of peroxynitrite and apoptosis.

Discovery of a Bulky 2-tert-Butyl Group Containing Primaquine Analogue That Exhibits Potent Blood-Schizontocidal Antimalarial Activities and Complete Elimination of Methemoglobin Toxicity

Abstract: To eliminate an unwarranted metabolic pathway of the quinoline ring, a set of two compounds, where C-2 position of the antimalarial drug primaquine is blocked by metabolically stable bulky alkyl group are synthesized. Compound 2 [R = C(CH3)3] of the series has produced excellent antimalarial efficacy against P. berghei and highly virulent multidrug-resistant P. yoelii nigeriensis strain in vivo. Compound 2 was also evaluated for methemoglobin (MetHb) toxicity. This study describes the discovery of a highly potent blood-schizontocidal antimalarial analogue 2, completely devoid of MetHb toxicity.

Nitric Oxide and Peroxynitrite in Health and Disease

Abstract: The discovery that mammalian cells have the ability to synthesize the free radical nitric oxide (NO) has stimulated an extraordinary impetus for scientific research in all the fields of biology and medicine. Since its early description as an endothelial-derived relaxing factor, NO has emerged as a fundamental signaling device regulating virtually every critical cellular function, as well as a potent mediator of cellular damage in a wide range of conditions. Recent evidence indicates that most of the cytotoxicity attributed to NO is rather due to peroxynitrite, produced from the diffusion-controlled reaction between NO and another free radical, the superoxide anion. Peroxynitrite interacts with lipids, DNA, and proteins via direct oxidative reactions or via indirect, radical-mediated mechanisms. These reactions trigger cellular responses ranging from subtle modulations of cell signaling to overwhelming oxidative injury, committing cells to necrosis or apoptosis. In vivo, peroxynitrite generation represents a crucial pathogenic mechanism in conditions such as stroke, myocardial infarction, chronic heart failure, diabetes, circulatory shock, chronic inflammatory diseases, cancer, and neurodegenerative disorders. Hence, novel pharmacological strategies aimed at removing peroxynitrite might represent powerful therapeutic tools in the future. Evidence supporting these novel roles of NO and peroxynitrite is presented in detail in this review.

Peroxynitrite: biochemistry, pathophysiology and development of therapeutics

Abstract: Peroxynitrite--the product of the diffusion-controlled reaction of nitric oxide with superoxide radical--is a short-lived oxidant species that is a potent inducer of cell death Conditions in which the reaction products of peroxynitrite have been detected and in which pharmacological inhibition of its formation or its decomposition have been shown to be of benefit include vascular diseases, ischaemia-reperfusion injury, circulatory shock, inflammation, pain and neurodegeneration In this Review, we first discuss the biochemistry and pathophysiology of peroxynitrite and then focus on pharmacological strategies to attenuate the toxic effects of peroxynitrite These include its catalytic reduction to nitrite and its isomerization to nitrate by metalloporphyrins, which have led to potential candidates for drug development for cardiovascular, inflammatory and neurodegenerative diseases

Animal models in type 2 diabetes research: an overview.

Abstract: Type 2 diabetes is a complex and heterogeneous disorder presently affecting more than 100 million people worldwide and causing serious socio-economic problems. Appropriate experimental models are essential tools for understanding the pathogenesis, complications, and genetic or environmental influences that increase the risks of type 2 diabetes and testing of various therapeutic agents. The animal models of type 2 diabetes can be obtained either spontaneously or induced by chemicals or dietary or surgical manipulations and/or by combination thereof. In recent years, large number of new genetically modified animal models including transgenic, generalized knock-out and tissue-specific knockout mice have been engineered for the study of diabetes. This review gives an overview on the animal models of type 2 diabetes with reference to their origin/source, characteristic features, underlying causes/mechanism(s), advantages and disadvantages to the investigators in diabetes research. In addition, it especially describes the appropriate selection and usefulness of different animal models in preclinical testing of various new chemical entities (NCEs) for the treatment of type 2 diabetes.

The Pharmacological Potential of Rutin.

Abstract: The contemporary scientific community has presently recognized flavonoids to be a unique class of therapeutic molecules due to their diverse therapeutic properties. Of these, rutin, also known as vitamin P or rutoside, has been explored for a number of pharmacological effects. Tea leaves, apples, and many more possess rutin as one of the active constituents. Today, rutin has been observed for its nutraceutical effect. The present review highlights current information and health-promoting effects of rutin. Along with this, safety pharmacology issues and SAR of the same have also been discussed.