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Ramesh Chander Farhan Rizvi A. K Khanna Ram Pratap 《Indian journal of clinical biochemistry : IJCB》2003,18(2):71-79
Guggulsterone, a mixture of cis (E) and trans (Z) isomers (7∶3 w/w) was synthesized from 16-DPA. The isomers were separated
by column chromatography and evaluated for cardioprotective and antioxidant activities. Myocardial necrosis induced by isoproterenol
in rats caused marked increase in serum creatine phosphokinase and glutamate pyruvate transaminase. Simultaneously in ischemic
heart, phospholipase, xanthine oxidase and lipid peroxides were enhanced following depletion of glycogen, phospholipids and
cholesterol. Treatment with guggulsterone and its both isomers at the dose of 50 mg/kg po., significantly protected cardiac
damage as assessed by the reversal of blood and heart biochemical parameters in ischemic rats. The cardioprotective activity
of guggulsterone and of both the isomers were compared with that of gemfibrozil at the same doses. Guggulsterone and both
the isomers at tested concentrations (5–20mM) inhibited oxidative degradation of lipids in human low-density lipoprotein and
rat liver microsomes induced by metal ionsin vitro. The drug counteracted against the generation of superoxide anions (O2) and hydroxyl radicals (OH−) in non-enzymic test systems. It is suggested that cardioprotective and antioxidant activities of synthetic guggulsterone
and guggulsterone obtained from gum resinCommiphora mukul that contains isomers E & Z in the ratio of 46∶54w/w are the same. 相似文献
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2011年,作为全球最大能源使用国以及二氧化碳排放国,中美的建筑业所消耗的能源分别占到全国能源总消耗量的25%和40%。在建筑节能领域,绿色建筑的出现为消除建筑业所带来的对能源以及环境的负面影响提供了解决方法。为了促进绿色建筑的市场转型,推进设计和施工的差异化,中美均制定了国家绿色建筑分等评级程序以及配套政策。1998年,美国绿色建筑协会首次推出能源与环境先导设计(LEED),而中国政府则于2008年建立了中国绿色建筑评价标识(GBEL)。本文对美国LEED与中国GBEL评级程序、流程、评分系统以及扶持政策作了对比分析,研究发现,虽然两国所采用的绿色建筑设计以及操作评级程序的评分等级较为相似,它们在项目管理、评分要求和分配以及扶持政策类型等方面存在差异。美国能源与环境先导设计是由建筑产业利益相关者委员会制定并实施管理的。判断是否达到认证水平的灵活性更高。中国绿色建筑评价标识则是由政府操控的。判断是否达到评级水平的要求更为严格。但是,中国政府将在2014年下半年对中国绿色建筑评价标识的评级程序作出修正。本文对评级程序以及扶植政策的相似点以及差异是如何影响绿色建筑技术以及市场的发展作了分析,还讨论了绿色建筑未来发展可能面临的挑战以及政策导向意义。 相似文献
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N. Khanna A. Garg K. K. Sharma R. Khosla 《Indian journal of clinical biochemistry : IJCB》1997,12(1):86-90
In the present study which was aimed to see the effect of zinc on pentylenetetrazole induced convulsive threshold in rats we found that zinc sulfate 100 μg intracerebroventricularly) and pentylenetetrazole (50 mg/kg intraperitoneally) produced dose related seizure activity; however, pretreatment with zinc decreased the threshold, increased the severity, incidence of multiple seizures and total duration of pentylenetetrazole induced seizures. Diazepam (5 mg/kg intraperitoneally) pretreatment increased the threshold and lowered the incidence of convulsions in zinc induced seizures which further confirms that the convulsive effect of zinc is through inhibition of gamma aimino butyric acid. 相似文献
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Tarun Khanna 《Research Policy》1995,24(6)
In a thirty-year period, firms in the high-end computer industry compete for technological leadership with select subgroups of firms. A clustering technique is used to identify these subgroups of firms. In each of the three such ‘races’ that I identify, a firm's racing rivals influence the evolution of its own technology frontier. This approach complements life-cycle and other models of technological evolution. A central role is assigned to strategic interactions between firms. Different kinds of strategic interactions lead to intra-race and inter-race behavior. I demonstrate how such inter-firm interactions map into technological evolution at the industry level and suggest that the patterns seen here can help us understand technological evolution in a range of environments. 相似文献
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Pankaj Abrol Umesh Mehta Harbans Lal 《Indian journal of clinical biochemistry : IJCB》2002,17(1):64-68
Vitamin A status was measured in 50 pre-school children with acute and persistent diarrhoea. It was measured by (a) Fluorometric
micromethod and (b) Conjunctival impression cytology (CIC). The results were compared with 25 normal children. Vitamin A status
was lower in children with persistent diarrhoea whereas the results were comparable between the children with acute diarrhoea
and control subjects. 相似文献
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Ramesh Chander A. K. Khanna Kanwal Raj A. K. Rastogi 《Indian journal of clinical biochemistry : IJCB》2005,20(1):153-159
Indian black tea; CTC leaf and dust, produced by Tata Tea Limited, Kolkata, (India) was studiedin vitro as potential scavenger of oxygen free radicals. Super oxide anions were generated in a system containing xanthine—xanthine
oxidase (enzymic system) and by NADH- phenozine methosulphate (non enzymic system). Anions were assayed in terms of uric acid
formation and reduction of nitroblue tetrazolium salt, which were shown to be suppressed by tea extracts. Extracts from both
leaf and dust also inhibted the formation of hydroxyl radicalsin vitro in the enzymic system comprising hypoxanthine—Cu+2—sodium ascorbate and xanthine oxidase and in non enzymic system of deoxyribose—Cu+2—sodium ascorbate and H2O2 as well as the Cu+2 induced lipid peroxidation in human low density lipoprotein. Feeding with black tea in normal rats for sixty days increased
their antioxidant activity and their liver microsomes were shown to be protected against peroxidation of lipids as stimulated
by metal ions with enzymic or non enzymic reactants. Furthermore feeding with tea extracts in normal as well as triton WR—1339
induced hyperlipidemic rats caused decrease in their plasma levels of total cholesterol, phospholipids and triglycerides.
The antioxidant and lipid lowering activities of both extracts from CTC leaf and dust tea was comparable and may be due to
the presence of natural products like catechin and others. 相似文献
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Pankaj Abrol Neeraj Sharma Harbans Lal 《Indian journal of clinical biochemistry : IJCB》1997,12(2):125-127
Serum vitamin E and cholesterol concentrations were measured in 50 children with protein energy malnutrition (PEM) and results
were compared with a group of 50 normal controls. Mean serum vitamin E concentration as well as vitamin E/cholesterol ratio
were found to be reduced in children with PEM while their mean serum cholesterol level was not significantly different from
the control group. Data suggest that the reduced levels of serum vitamin E in PEM may be a result of malnutrition per se. 相似文献
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Thirty patients with thalassemia major receiving repeated blood transfusion were studied to see their serum parathyroid hormone
(PTH) and calcium status. Serum PTH, serum and 24 h urinary calcium, and serum alkaline phosphatase, phosphorus, and albumin-corrected
calcium levels were determined. Half of these patients, in addition to transfusion, were also supplemented with vitamin D
(60,000 IU for 10d) and calcium (1500 mg/day for 3 months). Serum PTH, and serum and 24 h urinary calcium concentrations of
the patients receiving transfusions were found to be significantly reduced while their serum alkaline phosphatase, phosphorus,
and albumin-corrected calcium levels were not significantly altered when compared to the respective mean values for the control
group. Vitamin D and calcium supplementation significantly increased their serum PTH and calcium levels. Supplementations
also increased urinary excretion of calcium. The results thus suggest that patients with thalassemia have hypoparathyroidism
and reduced serum calcium concentrations that in turn were improved with vitamin D and calcium supplementation. 相似文献