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Goyal A, Singh AK, Gupta S. Acute extradural haematoma occurring during twistdrill craniostomy for chronic subdural haematoma. Br J Neurosurg 2002; 16:294-5. [PMID: 12201401 DOI: 10.1080/02688690220148914] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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427
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Singh AK, Raghubanshi AS, Singh JS. Medical ethnobotany of the tribals of Sonaghati of Sonbhadra district, Uttar Pradesh, India. JOURNAL OF ETHNOPHARMACOLOGY 2002; 81:31-41. [PMID: 12020925 DOI: 10.1016/s0378-8741(02)00028-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The present ethnobotanical exploration study presents the folk medicinal uses of certain plants by tribes of the Sonbhadra district in the Uttar Pradesh state of India. One hundred and twenty five plants from 57 families, which are therapeutically used against different diseases, such as cough, cold, dysentery, diarrhoea, ulcers, diabetes, male and female weakness, snake-bite and skin disorders are covered in this report. Part of the plant used, dosage and the mode of drug administration in different ailments are described.
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428
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Gupta V, Kumar S, Singh AK, Tatke M. Glossopharyngeal schwannoma : a case report and review of literature. Neurol India 2002; 50:190-3. [PMID: 12134186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
We report a rare case of glossopharyngeal schwannoma whose clinical presentation and the radiological work up suggested an acoustic schwannoma. The diagnosis was made at surgery, once attachment to ninth cranial nerve was seen. The clinical presentation, radiological features and surgical findings of the glossopharyngeal schwannoma are presented along with the review of literature.
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Singh AK. Acute effects of acephate and methamidophos and interleukin-1 on corticotropin-releasing factor (CRF) synthesis in and release from the hypothalamus in vitro. Comp Biochem Physiol C Toxicol Pharmacol 2002; 132:9-24. [PMID: 12039681 DOI: 10.1016/s1532-0456(02)00020-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Acute effects of Ace, Meth and IL-1 on AChE activity, ACh and CRF mRNA levels in, and CRF-release from the hypothalamus were studied in vitro. The hypothalamus samples were dissected from the rat brain and were incubated in vitro with IL-1, Ace or Meth in the presence or absence of Dex, Atrop, PTL, PROP and GABA. Ace and Meth, but not IL-1, inhibited AChE activity, while all three compounds; (1) increased ACh and CRF mRNA levels in and CRF release from; (2) activated the CRE promoter region of CRF-gene in: and (3) increased cFos binding to the AP-1 region of the CRF-gene in the hypothalamus. Dex suppressed the effects of IL-1, possibly by inducing the nGRE regulatory sites of the CRF-gene. Dex, however, did not modulate the effects of Ace and Meth on the hypothalamus, which may be attributed to the failure of Dex to modulate the CRF-gene's nGRE regulatory sites. Atrop caused 80-90% inhibition of the effects of IL-1, but caused only 50-65% inhibition of the effects of Ace or Meth on CRF mRNA levels in and CRF release from the hypothalamus. PTL did not affect, while PROP slightly attenuated the effects of IL-1 and the insecticides on the hypothalamus. GABA attenuated the effects of the insecticides but not the effects of IL-1 on the hypothalamus. This suggests that the IL-1-induced augmentation of CRF synthesis in and release from the hypothalamus is mediated through a cholinergic pathway, while the insecticide-induced augmentation of CRF synthesis in and release from the hypothalamus is mediated through the cholinergic and GABAergic pathways. The insecticides, but not IL-1, disrupt feedback regulation of CRF synthesis in and release from the hypothalamus.
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430
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Goyal A, Singh AK, Gupta V, Tatke M. Spinal epidural cavernous haemangioma: a case report and review of literature. Spinal Cord 2002; 40:200-2. [PMID: 11965560 DOI: 10.1038/sj.sc.3101248] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN A case report of purely epidural cavernous haemangioma with MRI appearance and pathological features. OBJECTIVE To present a rare case of extradural mass with differential diagnosis. SETTING Delhi, India. METHOD A 55-year-old man presented with progressive weakness and diminished sensation in both lower limbs. MRI demonstrated a pure extradural mass with no bony invasion. Histopathology of the lesion revealed a typical cavernous haemangioma. RESULT The patient showed significant improvement after surgery. CONCLUSION Radiological presentation could be confusing in a purely epidural cavernous haemangioma. Awareness of the characteristics of the lesion will facilitate diagnosis and treatment of the lesion.
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431
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Singh AK, Bhatnagar A, Singh T, Shankar LR. Development and validation of hydroxy ethyl starch kits for instant use in gastroesophageal reflux and gastric motility studies. Nucl Med Commun 2002; 23:373-7. [PMID: 11930191 DOI: 10.1097/00006231-200204000-00011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A reduction method based on stannous chloride is described to prepare hydroxy ethyl starch kits for gastrointestinal reflux and gastric motility studies. Following verification of the consistency of radiolabelling, in vitro experiments were carried out to validate 99mTc hydroxy ethyl starch as a liquid phase and solid phase gastric motility imaging radiotracer. Gastroesophageal reflux, liquid phase and solid phase studies were then conducted in 13 adult volunteers to examine the in vivo stability of the radiotracer. High labelling efficiency (>95% when prepared at neutral pH) was consistently achieved, which remained stable in conditions simulating gastric environment. Twelve of the 13 volunteers did not show absorption of any radioactivity from the gastro-intestinal tract. 99mTc hydroxy ethyl starch is a new agent suitable for gastroesophageal reflux and gastric motility studies. It is available in kit form and is a more 'physiological' agent than 99mTc sulphur colloid for preparing a solid radioactive meal. 99mTc hydroxy ethyl starch represents a true carbohydrate meal, and unlike 99mTc sulphur colloid, is easy to prepare and can easily be standardized to produce a standard vegetarian meal.
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432
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Gupta V, Singh AK, Kumar S, Sinha S. Familial trigeminal neuralgia. Neurol India 2002; 50:87-9. [PMID: 11960159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Familial trigeminal neuralgia is infrequent. A report of a couple and their son being afflicted by this malady is presented. The clinical features, radiological findings and surgical management are discussed and literature reviewed.
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433
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Awasthi K, Singh AK, Srivastava ON. Synthesis and characterization of lanthanum carbide nanotubes. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2002; 2:67-71. [PMID: 12908323 DOI: 10.1166/jnn.2002.078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Lanthanum carbide nanotubes have been synthesized by d.c. arc evaporation (approximately 20-30 V, approximately 200 Amp) of lanthanum metal (90 wt.%)-loaded graphite rod in a helium atmosphere (665 mbar). To explore the possibility of formation of lanthanum carbide nanotubes, the experiments were carried out with lanthanum metal in different concentrations (i.e., 30, 50, 70, and 90 wt.%) in the graphite rod. The as-synthesized samples were characterized by transmission electron microscopy and X-ray diffractometry. Lanthanum carbide nanotubes (LCNTs) with a diameter of approximately 65 to 95 nm and a length of approximately 0.2 to 1.5 microns were obtained in this study.
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434
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Minhas KS, Sidhu JS, Mudahar GS, Singh AK. Flow behavior characteristics of ice cream mix made with buffalo milk and various stabilizers. PLANT FOODS FOR HUMAN NUTRITION (DORDRECHT, NETHERLANDS) 2002; 57:25-40. [PMID: 11855619 DOI: 10.1023/a:1013106116587] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ice cream made with buffalo milk, using optimum levels of various stabilizers of plant origin, was evaluated for its flow behavior characteristics, with the objective of producing an acceptable quality product. The minimum variation in the viscosity of mix was observed at three rates of shear (348.88, 523.33 and 1046.66 S(-1)) for all ice cream mixes. The flow behavior index (n) of all the mixes having optimum levels of various stabilizers was observed to be less than 1; indicating their pseudoplastic nature. Consistency coefficient (m) of sodium alginate was found to be 1.19; highest among all the stabilizers, followed by gelatin (1.17), karaya (1.08), guar gum (0.75), acacia gum (0.70), ghatti gum (0.36), and the control (0.29). The consistency coefficient (m) signifies the apparent viscosity of the pseudoplastic fluid. The viscosity of the mixes having various stabilizers (optimum levels) was found to be in descending order: Sodium alginate, gelatin, karaya, guar gum, acacia, ghatti and control.
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435
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Gupta R, Gupta VP, Sarna M, Bhatnagar S, Thanvi J, Sharma V, Singh AK, Gupta JB, Kaul V. Prevalence of coronary heart disease and risk factors in an urban Indian population: Jaipur Heart Watch-2. Indian Heart J 2002; 54:59-66. [PMID: 11999090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
BACKGROUND The prevalence of risk factors for coronary heart disease has been inadequately studied in India. A repeat cross-sectional survey was carried out to evaluate the changes in the major coronary risk factors in the urban population of Jaipur previously studied in the early 1990s. METHODS AND RESULTS Randomly selected adults > or =20 years of age were studied using stratified sampling. The target study sample was 1800 with a population proportionate gender distribution (males 960, females 840). Coronary risk factors, anthropometric variables, blood pressure, ECG, fasting blood glucose and lipids were evaluated. A total of 1123 subjects (62.4%) (males 550, females 573) were examined. Fasting blood samples were available in 523 males and 559 females. Overall coronary heart diesase prevalence, diagnosed by history or ECG changes, was found in 34 males (6.18%) and 58 females (10.12%). Risk factor prevalence showed that smoking/tobacco use was present in 201 males (36.5%) and 67 females (11.7%). Physical inactivity, either work-related or leisure time, was seen in 157 males (28.5%) and 130 females (22.7%). Hypertension (> or =140 and/or 90 mmHg) was present in 200 males (36.4%) and 215 females (37.5%). Diabetes diagnosed by history or fasting glucose > or =126 mg/dl was found in 72 males (13.1%) and 65 females (11.3%). Obesity, body mass index > or =27 kg/m2 was present in 135 males (24.5%) and 173 females (30.2%), while truncal obesity (waist:hip >0.9 males, >0.8 females) was found in 316 males (57.4%) and 392 females (68.4%). The most common dyslipidemia in both males and females was low HDL-cholesterol (<40 mg/dl: males 54.9%, females 54.2%). High total cholesterol levels of > or =200 mg/dl (males 37.4%, females 4.1%), high LDL-cholesterol levels of > or =130 mg/dl (males 37.0%, females 45.8%) and high levels of triglycerides > or = 150 mg/dl (males 32.3%, females 28.6%) were also seen in a significant number. Hypertension, obesity, truncal obesity, diabetes and dyslipidemias increased significantly with age in both males and females (Mantel-Haenzel chi2 for trend, p<0.05). CONCLUSIONS There is a high prevalence of standard coronary risk factors--smoking, physical inactivity, hypertension, hypercholesterolemia, diabetes and obesity--as well as factors peculiar to south Asians--truncal obesity, low HDL-cholesterol and high triglycerides--in this urban Indian population. As compared to a previous study in the early 1900s in a similar population, there is a significant increase in the number of people with obesity, diabetes and dyslipidemias.
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436
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Singh AK, Eldho TLI, Prinz D. Integrated watershed approach for combating drought in a semi-arid region of India: the case of Jhabua watershed. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2002; 46:85-92. [PMID: 12380978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The integrated watershed management approach for the semi-arid regions of India is considered to be very important due to the inadequate availability of water resources. The drought experienced in recent years has brought on an environmental and socio-economic crisis in these regions. The role of the watershed management has been crucial and development of alternative water resources has been critically important. To overcome the isolated sectoral development planning and implementation, as was done in many of the previous land based programs in India, an integrated concept of watershed development through participatory planning and actions has been followed for combating drought in Jhabua watershed in Madhya Pradesh state, India. This research paper will look into the successful watershed management experience of our on-going research project, and appropriate watershed strategies for the Jhabua watershed.
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437
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Singh AK, Wilson MT, Hong S, Olivares-Villagómez D, Du C, Stanic AK, Joyce S, Sriram S, Koezuka Y, Van Kaer L. Natural killer T cell activation protects mice against experimental autoimmune encephalomyelitis. J Exp Med 2001; 194:1801-11. [PMID: 11748281 PMCID: PMC2193577 DOI: 10.1084/jem.194.12.1801] [Citation(s) in RCA: 320] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Experimental autoimmune encephalomyelitis (EAE) serves as a prototypic model for T cell-mediated autoimmunity. V(alpha)14 natural killer T (NKT) cells are a subset of T lymphocytes that recognize glycolipid antigens presented by the nonpolymorphic major histocompatibility complex (MHC) class I-like protein CD1d. Here, we show that activation of V(alpha)14 NKT cells by the glycosphingolipid alpha-galactosylceramide (alpha-GalCer) protects susceptible mice against EAE. beta-GalCer, which binds CD1d but is not recognized by NKT cells, failed to protect mice against EAE. Furthermore, alpha-GalCer was unable to protect CD1d knockout (KO) mice against EAE, indicating the requirement for an intact CD1d antigen presentation pathway. Protection of disease conferred by alpha-GalCer correlated with its ability to suppress myelin antigen-specific Th1 responses and/or to promote myelin antigen-specific Th2 cell responses. alpha-GalCer was unable to protect IL-4 KO and IL-10 KO mice against EAE, indicating a critical role for both of these cytokines. Because recognition of alpha-GalCer by NKT cells is phylogenetically conserved, our findings have identified NKT cells as novel target cells for treatment of inflammatory diseases of the central nervous system.
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438
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Abstract
Calcifying pseudoneoplasm or fibro-osseous lesion of the CNS is uncommon. We report a case in a 6-year-old boy who presented with generalized tonic-clonic seizures for 6 months. There was a calcified mass in the depth of the left temporal lobe, which on histology showed collagenous nodules surrounded by spindle cells and seperated by chondromyxoid matrix. The only other report of such a lesion in a child is of a 12-year-old boy with an epidural lesion at C-6 level. It is important to recognize this entity since it is slow growing with a good prognosis.
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439
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Légaré D, Cayer S, Singh AK, Richard D, Papadopoulou B, Ouellette M. ABC proteins of Leishmania. J Bioenerg Biomembr 2001; 33:469-74. [PMID: 11804188 DOI: 10.1023/a:1012870904097] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
ABC proteins were first characterized in the protozoan parasite Leishmania while studying mechanisms of drug resistance. PGPA is involved in resistance to arsenite and antimonite and it most likely confers resistance by sequestering metal-thiol conjugates into an intracellular vesicle. PGPA is part of gene family with at least four more members which are in search of a function. Leishmania also contains a P-glycoprotein, homologous to the mammalian MDR1, that is involved in multidrug resistance. The ongoing genome project of Leishmania has pinpointed several novel ABC transporters and experiments are carried out to study the function of the ABC proteins in drug resistance and in host-pathogen interactions.
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440
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Gupta A, Gupta R, Lal B, Singh AK, Kothari K. Prevalence of coronary risk factors among Indian physicians. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 2001; 49:1148-52. [PMID: 11996433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
BACKGROUND AND OBJECTIVES Prevalence of coronary risk factors has not been well studied in Indian physicians, therefore, to determine prevalence of selected lifestyle and biochemical coronary risk factors we performed this study. METHODS Physicians attending a national conference were invited to participate. Of the 1000 questionnaires circulated 256 physicians (221 males, 35 females) responded and were examined for presence of smoking, obesity, truncal obesity, hypertension and ECG abnormalities. Two hundred and thirty four physicians (91.4%, 203 males, 31 females) underwent a fasting blood examination for determination of glucose and lipid profile. Subjects were divided into three age groups: Group I aged < 40 years; Group II 40-49 years; and Group III > or = 50 years. RESULTS Mean age of the study population was 41.7 +/- 9.3 years (range 26-70). There was no significant difference in the distribution of height, weight, body-mass index (BMI), waist and hip circumference and waist-hip ratio (WHR) in different age-groups. Systolic blood pressure (BP) and fasting glucose and triglyceride levels increased with age in both males and females, while diastolic BP, total - LDL and HDL cholesterol levels did not change. Smoking or tobacco use was seen in five males (2.3%). Prevalence of obesity (BMI > or = 25.0 kg/m2) was in 104 (48.6%) males and 18 (51.4%) females. Truncal obesity diagnosed by WHR > 0.9 in males and > 0.8 in females was in 160 (72.4%) males and 23 (65.7%) females and a large waist circumference, > or = 100 cm in males and > or = 90 cm in females, was in 58 (26.2%) males and 7 (20.0%) females. Hypertension (> or = 140/90) was in 74 (33.5%) males and 7 (20%) females. A high prevalence of diabetes diagnosed using fasting blood glucose > or = 126 mg/dl or previous history was noted in males 19 (9.4%), females 4 (12.9%). Prevalence of high total cholesterol levels > or = 200 mg/dl was in 91 (44.8%) males and 10 (32.3%) females. High LDL cholesterol level (> or = 100 mg/dl) was in 144 (70.9%) males and 22 (70.9%) females and LDL levels > or = 130 mg/dl in 70 (34.5%) males and 9 (29.0%) female physicians. High triglyceride levels (> or = 200 mg/dl) were in 38 (18.7%) males and 4 (12.9%) females. Electrocardiographic abnormalities were present in seven subjects: Q-waves in two males and one female and ST-T changes in three males and one female. BMI correlated significantly (p < 0.05) with systolic BP, fasting glucose, and triglycerides and WHR with systolic BP, diastolic BP, fasting glucose, cholesterol and triglyceride levels. CONCLUSIONS There is a high prevalence of obesity, truncal obesity, hypertension and hypercholesterolaemia in Indian physicians while smoking, low HDL cholesterol and hypertriglyceridemia is low. The overall coronary risk is lower among Indian physicians as compared to previous Indian population studies.
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441
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Sengupta D, Kumar R, Singh AK, Prasad R. Radon exhalation and radiometric prospecting on rocks associated with Cu-U mineralizations in the Singhbhum shear zone, Bihar. Appl Radiat Isot 2001; 55:889-94. [PMID: 11761114 DOI: 10.1016/s0969-8043(00)00344-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Singhbhum thrust belt is a 200 km long arcuate orogenic belt in Bihar, eastern India. The huge mineral resources, viz. copper, uranium, magnetite, apatite and molybdenite, etc., make it significant from an economic as well as a geological point of view. The belt hosts three types of mineralization: sulphides of copper and other metals, uranium oxides and apatite-magnetite. Several distinct geological episodes are responsible for the evolution of mineralization and the thrust zone itself. Extensive and reliable radiometric prospecting and assaying have been carried out by us for the past 5 years from Dhobani in the east to Turamdih in the west of the Singhbhum shear zone. The present work indicates uranium mineralization in the Pathargora-Rakha area presently being mined for copper and also within areas in the vicinity of Bhatin. Studies on radon emanation have also been undertaken in some parts of the shear zone which indicate reasonably high radon emanation of the soils and rocks studied. This suggests the need for regular monitoring and suitable controls on the mine environment (air quality) and its vicinity. Radon emanation studies coupled with gamma-ray spectrometry and the subsequent modelling of the radiometric and radon measurements will help in the application of radon as a geophysical tracer in exploration of radioactive ore bodies and in radon risk assessment as well as in delineating active and passive faults and even in petroleum exploration.
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442
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Singh AK, Papadopoulou B, Ouellette M. Gene amplification in amphotericin B-resistant Leishmania tarentolae. Exp Parasitol 2001; 99:141-7. [PMID: 11846524 DOI: 10.1006/expr.2001.4663] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two Leishmania tarentolae cells were selected step by step for resistance to the polyene antibiotic amphotericin B, a second-line drug against the parasite Leishmania. One of the mutants was cross-resistant to ketoconazole. DNA amplification was observed in both mutants. The amplicons were extrachromosomal circles and were derived from different chromosomes. In one mutant the circle was unusually stable as it remained within the cell despite numerous passages in the absence of the drug. A circumstantial link between the copy number of amplicons and the resistance levels was established. Gene transfection experiments indicated that the link between the locus amplified and the resistance levels was not straightforward and possibly several mutations act together to lead to amphotericin B resistance.
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443
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Alfonta L, Willner I, Throckmorton DJ, Singh AK. Electrochemical and quartz crystal microbalance detection of the cholera toxin employing horseradish peroxidase and GM1-functionalized liposomes. Anal Chem 2001; 73:5287-95. [PMID: 11721931 DOI: 10.1021/ac010542e] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An ultrasensitive method for the detection of the cholera toxin (CT) using electrochemical or microgravimetric quartz crystal microbalance transduction means is described. Horseradish peroxidase (HRP) and GM1-functionalized liposomes act as catalytic recognition labels for the amplified detection of the cholera toxin based on highly specific recognition of CT by the ganglioside GM1. The sensing interface consists of monoclonal antibody against the B subunit of CT that is linked to protein G, assembled as a monolayer on an Au electrode or an Au/ quartz crystal. The CT is detected by a "sandwich-type" assay on the electronic transducers, where the toxin is first bound to the anti-CT-Ab and then to the HRP-GM1-ganglioside-functionalized liposome. The enzyme-labeled liposome mediates the oxidation of 4-chloronaphthol (2) in the presence of H2O2 to form the insoluble product 3 on the electrode support or the Au/quartz crystal. The biocatalytic precipitation of 3 provides the amplification route for the detection of the CT. Formation of the insulating film of 3 on the electrode increases the interfacial electron-transfer resistance, Ret, or enhances the electrode resistance, R', parameters that are quantitatively derived by Faradaic impedance measurements and chronopotentiometric analyses, respectively. Similarly, the precipitate 3 formed on the Au/quartz crystal results in a mass increase on the transducer that is reflected by a decrease in the resonance frequency of the crystal. The methods allow the detection of the CT with an unprecedented sensitivity that corresponds to 1.0 x 10(-13) M.
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444
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Wong W, Singh AK. Urinary cytokines: clinically useful markers of chronic renal disease progression? Curr Opin Nephrol Hypertens 2001; 10:807-11. [PMID: 11706309 DOI: 10.1097/00041552-200111000-00012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Many factors that drive glomerular and tubulointerstitial fibrogenesis have been identified. These include hemodynamic factors, chemokines, inflammatory mediators, cytokines, and lipids. These strides in knowledge are important in identifying those patients at increased risk of progressive renal disease as well as in developing targets for therapeutic interventions. Identifying 'progressors' is crucial since the distribution of the slope of the glomerular filtration rate of patients with chronic kidney disease is not normal. Some patients appear to progress very rapidly, such as those with diabetes, whereas other patients fail to progress at all. Developing strategies targeted at identifying the fast from the slow progressors is therefore of paramount importance if we are to deploy resources rationally in the management of patients with chronic kidney disease. The use of urinary cytokine markers as predictors of progression of renal disease is reviewed in this paper.
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445
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Singh AK, Kedor-Hackmann ER, Santoro MI. Development and validation of a chiral liquid chromatographic method for the determination of atenolol and metoprolol enantiomers in tablet preparations. J AOAC Int 2001; 84:1724-9. [PMID: 11767137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Atenolol (AT) and metoprolol (MT) are predominantly used in the treatment of angina pectoris, certain arrhythmias, systemic hypertension, and several other cardiovascular disorders. Both compounds are produced commercially in the racemic form, although the S-form is responsible for the desired biological effect. This paper describes a simple, rapid, precise, and accurate method for separating the enantiomers of AT and MT. AT isomers are separated by using a Chiralcel OD column (250 x 4.6 mm, 10 microm), hexane-ethanoldiethylamine-acetic acid (60 + 40 + 0.2 + 0.2, v/v/v/v) as the mobile phase, and a flow rate of 1.0 mL/min. MT isomers are separated by using a mobile phase with the same components in the following proportions (40 + 60 + 0.2 + 0.2, v/v/v/v) and a flow rate of 0.8 mL/min. Ultraviolet detection was at 276 nm for both analytes. The coefficients of variation (CVs) and average recoveries (ARs) for the R-enantiomers in samples A, B, C, D, and E were 1.15 and 101.06%, 0.74 and 99.25%, 1.05 and 102.57%, 0.84 and 101.57%, and 0.86 and 98.62%, respectively. The CVs and ARs for the S-enantiomers in samples A, B, C, D, and E were 1.33 and 98.87%, 0.99 and 100.76%, 1.17 and 101.69%, 1.26 and 100.39%, and 1.40 and 99.39%, respectively. The standard curves of R-AT, S-AT, R-MT, and S-MT showed good linearity over the concentration range studied with correlation coefficients of 0.9991, 0.998, 0.9988, and 0.999, respectively.
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Uhlig K, Sarnak MJ, Singh AK. New approaches to the treatment of calcium and phosphorus abnormalities in patients on hemodialysis. Curr Opin Nephrol Hypertens 2001; 10:793-8. [PMID: 11706307 DOI: 10.1097/00041552-200111000-00010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Disturbances in calcium and phosphorus are common in patients who are on chronic hemodialysis. Current therapy consists mainly of administration of calcium-containing phosphate binders and calcitriol. However, the use of these therapies has been limited by both iatrogenic hypercalcemia and hyperphosphatemia. Indeed, hyperphosphatemia and elevations in the calcium x phosphorus product have recently been linked to increased mortality and a high burden of cardiac calcifications on electron-beam computed tomography. Novel therapeutic agents such as sevelamer and vitamin D analogs have thus been developed with the goal of decreasing oral calcium loading and hypercalcemia. We provide an algorithm for the management of calcium and phosphorus abnormalities, based on newer recommendations for tighter calcium and phosphorus control with a lower target for the calcium x phosphorus product.
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Singh AK. Hypertension in elderly. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 2001; 49:1129-30. [PMID: 11868878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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449
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Singh AK, Singh M. Profile of hypertension in elderly subjects. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 2001; 49:1130. [PMID: 11868879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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450
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Stanislaus R, Singh AK, Singh I. Lovastatin treatment decreases mononuclear cell infiltration into the CNS of Lewis rats with experimental allergic encephalomyelitis. J Neurosci Res 2001; 66:155-62. [PMID: 11592110 DOI: 10.1002/jnr.1207] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Mononuclear cell infiltration into the CNS and induction of inflammatory cytokines and iNOS in diseases like multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE) have been implicated in subsequent disease pathogenesis and progression. We report that Lovastatin treatment blocks the clinical disease and induction of inflammatory cytokines and iNOS in spinal cords of MBP induced EAE rats. A significant number of the infiltrating cells in CNS were ED1+ cells of monocyte/macrophage lineage. To understand the mechanism of efficacy of Lovastatin against EAE, we examined the effect of Lovastatin on the transmigration of mononuclear cells into EAE spinal cord. The data presented here documents that Lovastatin treatment attenuates the transmigration of mononuclear cells possibly by down regulating the expression of LFA-1, a ligand for ICAM, in endothelial-leukocyte interaction. These results indicate that Lovastatin treatment prevents infiltration by mononuclear cells into the CNS of rats induced for EAE, thereby lessening the histological changes and clinical signs and thus ameliorating the disease. These observations indicate that Lovastatin treatment may be of therapeutic value against inflammatory disease process associated with infiltration of activated mononuclear cells into the tissue.
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MESH Headings
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Anti-Inflammatory Agents, Non-Steroidal/therapeutic use
- Cell Adhesion/drug effects
- Chemotaxis, Leukocyte/drug effects
- Cytokines/biosynthesis
- Cytokines/genetics
- Demyelinating Diseases/pathology
- Disease Models, Animal
- Drug Evaluation, Preclinical
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Endothelium, Vascular/pathology
- Enzyme Induction/drug effects
- Female
- Gene Expression Regulation/drug effects
- Intercellular Adhesion Molecule-1/metabolism
- Lovastatin/pharmacology
- Lovastatin/therapeutic use
- Lymphocyte Function-Associated Antigen-1/genetics
- Lymphocyte Function-Associated Antigen-1/metabolism
- Monocytes/drug effects
- Multiple Sclerosis/pathology
- Nitric Oxide Synthase/metabolism
- Nitric Oxide Synthase Type II
- Rats
- Rats, Inbred Lew
- Spinal Cord/drug effects
- Spinal Cord/metabolism
- Spinal Cord/pathology
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