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Blanchette HA, Nayak S, Erasmus S. Comparison of the safety and efficacy of intravaginal misoprostol (prostaglandin E1) with those of dinoprostone (prostaglandin E2) for cervical ripening and induction of labor in a community hospital. Am J Obstet Gynecol 1999; 180:1551-9. [PMID: 10368503 DOI: 10.1016/s0002-9378(99)70051-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE This clinical trial evaluated the efficacy of intravaginal misoprostol (prostaglandin E1) and compared it with that of dinoprostone (prostaglandin E2) for cervical ripening and induction of labor in a community hospital. STUDY DESIGN This study involved a retrospective analysis of 81 patients undergoing cervical ripening and induction of labor with prostaglandin E2 from May 1, 1996, to May 1, 1997. A comparison prospective analysis of 145 patients undergoing the same procedure with prostaglandin E1 from May 1, 1997 to May 1, 1998, was performed. RESULTS The mean time to delivery was significantly shorter with misoprostol (19.8 +/- 10.4 hours) than with prostaglandin E2 (31.3 +/- 13.0 hours, P <.001). Delivery within 24 hours of induction was significantly more frequent with misoprostol (71.9% of subjects vs 31.3%, P <.001). There was no difference in the cesarean delivery rate with misoprostol (25.6% vs 22.2%, P <.67). The incidence of uterine hyperstimulation was higher with prostaglandin E2 (7.4% vs 0.7%, P <.007). There were no uterine ruptures with prostaglandin E2. There were 2 uterine ruptures and 1 dehiscence with prostaglandin E1 in 3 patients with previous cesarean deliveries and 1 rupture in a patient without a history of uterine scarring. There was no difference in neonatal outcome, with the exception of a fetal death related to uterine rupture in the misoprostol group. CONCLUSIONS Compared with prostaglandin E2, misoprostol is more effective in cervical ripening and induction of labor, is as safe for patients who do not have a history of cesarean birth, may carry a higher incidence of uterine rupture, and should not be used for patients attempting vaginal birth after previous cesarean delivery.
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177
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Bhat KS, Nayak S. Flavin nucleotides in human lens: regional distribution in brunescent cataracts. Indian J Ophthalmol 1998; 46:233-7. [PMID: 10218307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
The biochemical mechanism(s) underlying brunescent cataracts remain unclear. Oxidative stress due to reactive oxygen species may have a role in the pigmentation process in eye lens. We have analysed human cataractous lenses for flavins by high-performance liquid chromatography (HPLC), since flavins are light sensitive and act as endogenous sensitizers generating reactive oxygen species in the eye. The most significant observation in this study is that higher levels of flavin nucleotides occur in brown lens compared to yellow lens. The concentration of flavin nucleotides (flavin monouncleotide, FMN + flavin adenine dinucleotide, FAD) was highest in the nuclear region of the lens followed by the cortical and capsule-epithelial regions. However, the ratio of FAD/FMN was lowest in the nuclear region of the lens followed by other regions. On the other hand, riboflavin was not detected in any of the lens (cataractous) regions. These results suggest that the observed increase in flavin nucleotides in the ocular tissue could contribute towards deepening of lens pigmentation.
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178
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Moses BV, Nayak S, Agarwal S, Augustine AJ. Upper gastrointestinal bleeding due to gangrenous cholecystitis. Indian J Gastroenterol 1998; 17:111. [PMID: 9695399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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179
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Nayak S, Lee PA, Witchel SF. Variants of the type II 3beta-hydroxysteroid dehydrogenase gene in children with premature pubic hair and hyperandrogenic adolescents. Mol Genet Metab 1998; 64:184-92. [PMID: 9719627 DOI: 10.1006/mgme.1998.2715] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To ascertain the potential role of heterozygosity for 3beta-hydroxysteroid (3beta-HSD) deficiency in children with premature pubic hair and adolescent girls with hyperandrogenism, we performed single-strand conformational polymorphism (SSCP) analysis of the 3beta-hydroxysteroid dehydrogenase type 2 (3beta-HSD2) gene in 34 hyperandrogenic patients. Three sequence variants, two missense mutations and a 3'-UTR sequence variant, were detected among seven patients and in none of 100 healthy control subjects. One of these seven patients carried Leu236 --> Ser on one 3beta-HSD2 allele and Glu318 --> STOP on one 21-hydroxylase (CYP21) allele. ACTH stimulation tests were performed in 5/7 patients with sequence variants and were compatible with decreased 3beta-hydroxysteroid dehydrogenase activity in three. Thus, 7 of 34 (20.6%) mildly hyperandrogenic patients carry heterozygous sequence variants of the 3beta-HSD2 gene. Since obligate heterozygotic carriers for congenital adrenal hyperplasia are typically asymptomatic, other genetic or environmental influences may contribute to the expression of hyperandrogenic symptoms in our patients.
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180
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Nayak S, Galili N, Buck CA. Immunohistochemical analysis of the expression of two serine-threonine kinases in the maturing mouse testis. Mech Dev 1998; 74:171-4. [PMID: 9651519 DOI: 10.1016/s0925-4773(98)00060-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Previously we identified two intronless serine-threonine kinase genes (Tsk1 and Tsk2) located 3 kb apart on mouse chromosome 16 (Galili, N., Baldwin, H.S., Lund, J., Reeves, R., Gong, W., Wang, Z., Roe, B.A., Emanuel, B.S., Nayak, S., Mickanin, C., Budraf, M.L., Buck, C.A., 1997. A region of mouse chromosome 16 is syntenic to the DiGeorge, velocardiofacial syndrome minimal critical region. Gen. Res. 7, 17-26). Tsk1 was identical to a putative testicular kinase reported by Bielke et al. (Bielke, W., Blaschke, R.J., Miescher, G.C., Zurcher, G., Andres, A.C., Ziemiecki, A., 1994. Characterization of a novel murine testis-specific serine/threonine kinase. Gene 13, 235-239). Here we document the expression patterns of each Tsk throughout spermiogenesis showing an initial association of Tsk1 with cells in meiotic metaphase and a later association of Tsk2 with tail-like structures in the lumen of the seminiferous tubule.
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181
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Galili N, Epstein JA, Leconte I, Nayak S, Buck CA. Gscl, a gene within the minimal DiGeorge critical region, is expressed in primordial germ cells and the developing pons. Dev Dyn 1998; 212:86-93. [PMID: 9603426 DOI: 10.1002/(sici)1097-0177(199805)212:1<86::aid-aja8>3.0.co;2-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Gscl, a paired-type homeobox gene, has been implicated in the pathology of DGS/VCFS by virtue of its genomic location and its structural similarity to the Gsc gene family. Immunohistochemical and in situ studies were performed to examine the expression pattern of this gene during embryonic development. A polyclonal antibody, generated to the full-length protein and shown to be specific for GSCL by both Western blotting and immunofluorescence, was used for immunohistochemical localization. Both in situ and antibody staining localized GSCL expression to a cluster of cells in the pons region of the developing brain. This GSCL expression pattern showed partial overlap with that of Pax6. More detailed immunohistochemistry revealed the GSCL in primordial germ cells during migration from the epithelium of the hindgut and later as they colonize the developing gonads. GSCL was not detected in tissues affected in DGS/VCSF.
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182
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Tandon S, Rao C, Moorthy K, Nayak S. A short-term plaque study using Lactitol as a non-sugar sweetener. J Clin Pediatr Dent 1998; 21:157-62. [PMID: 9484109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A short-term plaque study was undertaken in a group of 12 children of 8-12 years age to evaluate the effect of lactitol, 4-O (beta-galactosyl)-D-glucitol, on dental plaque pH, weight and microchemical composition. Sucrose which was taken as control and lactitol, were used in both solution form and sweets. Plaque pH recording was done at rest and post consumption periods at 5, 10, 20 and 30 minute intervals. Weight and microchemical analysis were done with 3-day-old plaque after consumption of sweets. Throughout the study period lactitol did not reach to a pH where the demineralization of enamel starts. A significant reduction in plaque formation, carbohydrate content, increase in calcium, phosphorus and protein in lactitol showed the potentiality of this bulk sweetener as non-cariogenic.
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183
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Lin S, Henzel WJ, Nayak S, Dennis D. Photoaffinity labeling by 4-thiodideoxyuridine triphosphate of the HIV-1 reverse transcriptase active site during synthesis. Sequence of the unique labeled hexapeptide. J Biol Chem 1998; 273:997-1002. [PMID: 9422761 DOI: 10.1074/jbc.273.2.997] [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: 02/05/2023] Open
Abstract
The active site of HIV-1 reverse transcriptase (HIV-1 RT) was investigated by photoaffinity labeling based on catalytic competence. A stable ternary elongation complex was assembled containing enzyme, DNA template (RT20), DNA primer molecule (P12), and the necessary dNTPs (one of which was alpha-32P-labeled) needed for primer elongation. The photoaffinity probe 4-thiodideoxyuridine triphosphate was incorporated uniquely at the 3' terminus of the 32P-labeled DNA product. Upon photolysis, the p66 subunit of a HIV-1 RT heterodimer (p66/p51) was uniquely cross-linked to the DNA product and subsequently digested by either trypsin or endoproteinase Lys-C. The labeled HIV-1 RT peptide was separated, purified, and finally subjected to Edman microsequencing. A unique radioactive hexapeptide (V276RQLCK281) was identified and sequenced. Our photoaffinity labeling results were positioned on the HIV-1 RT. DNA.Fab complex x-ray crystallography structure and compared with the suggested aspartic triad active site.
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184
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Witchel SF, Nayak S, Suda-Hartman M, Lee PA. Newborn screening for 21-hydroxylase deficiency: results of CYP21 molecular genetic analysis. J Pediatr 1997; 131:328-31. [PMID: 9290628 DOI: 10.1016/s0022-3476(97)70178-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Blood samples for plasma steroid hormone determinations and molecular genotype analysis of the 21-hydroxylase gene (CYP21) were obtained from 15 infants identified through a voluntary newborn screening program. Mutations were identified on both CYP21 alleles in 12 (80%) of 15 infants; all had confirmatory plasma 17-hydroxyprogesterone concentrations > 3500 ng/dl. No patient was found to carry mutations associated with late-onset 21-hydroxylase deficiency. Newborn screening hastened diagnosis in eight infants.
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185
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Williams KV, Nayak S, Becker D, Reyes J, Burmeister LA. Fifty years of experience with propylthiouracil-associated hepatotoxicity: what have we learned? J Clin Endocrinol Metab 1997; 82:1727-33. [PMID: 9177371 DOI: 10.1210/jcem.82.6.4011] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aim of this study was to determine the optimal management of patients with propylthiouracil (PTU) hepatotoxicity. A MEDLINE search for English language cases of PTU hepatotoxicity between 1966 and April 1996 was performed, and additional cases were cross-referenced. Twenty-seven cases were selected based on the availability of information on patient management after the onset of hepatotoxicity. Eighty-five percent of the selected cases met this criterion. A detailed summary of the management of two cases of PTU hepatotoxicity at our institutions is also provided. Although most patients recovered once PTU was stopped, seven patients died. Patients with PTU hepatotoxicity who survived were more likely to have received 131I during the course of their illness than those who died (P < 0.03, by Fisher's exact test). In our two patients, hyperbilirubinemia was linearly associated with progressively decreasing T4 levels (r = 0.91; P < 0.001) despite the presence of clinical thyrotoxicosis in one of the patients. These findings demonstrate the need for appropriate clinical evaluation and treatment of thyroid disease during the course of hepatotoxicity. Additionally, we report the first pediatric patient with PTU hepatotoxicity to undergo liver transplantation. The emerging role of liver transplantation in these patients is discussed.
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186
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Galili N, Baldwin HS, Lund J, Reeves R, Gong W, Wang Z, Roe BA, Emanuel BS, Nayak S, Mickanin C, Budarf MI, Buck CA. A region of mouse chromosome 16 is syntenic to the DiGeorge, velocardiofacial syndrome minimal critical region. Genome Res 1997; 7:399. [PMID: 9110179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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187
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Javeed H, Javeed N, Takla S, Bonaparte P, Nayak S. A nurse with neck pain and fever after a needle-stick. Hosp Pract (1995) 1997; 32:181-2. [PMID: 9006592 DOI: 10.1080/21548331.1997.11443416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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188
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Galili N, Baldwin HS, Lund J, Reeves R, Gong W, Wang Z, Roe BA, Emanuel BS, Nayak S, Mickanin C, Budarf ML, Buck CA. A region of mouse chromosome 16 is syntenic to the DiGeorge, velocardiofacial syndrome minimal critical region. Genome Res 1997; 7:17-26. [PMID: 9037598 DOI: 10.1101/gr.7.1.17] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
DGS and VCFS, haploinsufficiencies characterized by multiple craniofacial and cardiac abnormalities, are associated with a microdeletion of chromosome 22q11.2. Here we document synteny between a 150-kb region on mouse chromosome 16 and the most commonly deleted portion of 22q11.2. Seven genes, all of which are transcribed in the early mouse embryo, have been identified. Of particular interest are two serine/threonine kinase genes and a novel goosecoid-like homeobox gene (Gscl). Comparative sequence analysis of a 38-kb segment reveals similarities in gene content, order, exon composition, and transcriptional direction. Therefore, if deletion of these genes results in DGS/VCFS in humans, then haploinsufficiencies involving this region of chromosome 16 should recapitulate the developmental field defects characteristic of this syndrome.
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189
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Nayak S, Mohanty RC, Mohanty L. Growth rate of Ankistrodesmus falcatus and Scenedesmus bijuga in mixed culture exposed to monocrotophos. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 1996; 57:473-479. [PMID: 8672075 DOI: 10.1007/s001289900214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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190
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Dhar PK, Devi S, Rao TR, Kumari U, Joseph A, Kumar MR, Nayak S, Shreemati Y, Bhat SM, Bhat KR. Significance of lymphocytic sister chromatid exchange frequencies in ovarian cancer patients. CANCER GENETICS AND CYTOGENETICS 1996; 89:105-8. [PMID: 8697412 DOI: 10.1016/0165-4608(95)00071-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Very few studies report the analysis of sister chromatid exchanges in ovarian cancer patients. We tested the null hypothesis that SCE frequency increases with the advancing stages of ovarian cancer and follows a Poisson distribution. As controls we examined age- and sex-matched healthy volunteers who had no such past history. An increased average SCE frequency was observed in ovarian cancer patients (6.34 +/- 0.09) vis-à-vis controls (4.47 +/- 0.12). Further, the data also suggested a stage-wise increase in the SCE frequency.
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191
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Stambough JL, Nayak S. Frankel A paraplegia: a comparison of two spinal instrumentation systems. South Med J 1996; 89:597-602. [PMID: 8638199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Seventeen patients with unstable thoracolumbar fracture dislocations and Frankel A (complete) paraplegia had posterior spinal fusion and instrumentation--nine with Cotrel-Dubousset instrumentation and eight with Luque rod instrumentation (LRI). Both systems maintained fracture reduction, and fusion occurred in all cases within a mean of 42 months (range, 30 to 66 months). Operative time and associated blood loss was less in the LRI group. One patient with LRI had fracture of the sublaminar wires that did not lead to loss of reduction or nonunion. Both instrumentation systems provided long-term posterior spinal stabilization in these patients.
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192
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Majumder PP, Nayak S, Das RN, Bhattacharya SK. Genetic & cultural determinants of high-density lipoprotein cholesterol & serum triglycerides among Marwaris of Calcutta. Indian J Med Res 1996; 103:112-9. [PMID: 8714149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A genetic epidemiological study of serum lipid and lipoprotein levels was conducted among families of Marwaris residents in Calcutta. A total of 210 families, comprising over 100 individuals, were studied. Analyses were performed to estimate the genetic and environmental effects on the determination of high density lipoprotein cholesterol (HDL-C) and serum triglycerides (TG). Familial correlations for HDL-C and TG were estimated: parent-child and sib-sib correlations were found to be significant. Spouse correlations were not significant. Correlations between environments of siblings were significant. Genetic analysis of data on HDL-C and TG performed under a path model, taking genetic transmission and possible environmental associations among family members into account, indicated that lipid and lipoprotein levels adjusted and standardized for age, gender, education, occupation and disease status are primarily determined by genetic factors. The effects of environmental factors were also significant, although in comparison with genetic factors these effects were much smaller. The estimated genetic heritability for HDL-C was approximately 80 per cent, while that for TG was approximately 55 per cent. The genetic effects and environmental effects were not significantly different between adults and children.
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193
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Nayak S, Debata BK, Sahoo S. Rapid propagation of lemongrass (Cymbopogon flexuosus (Nees) Wats.) through somatic embryogenesis in vitro. PLANT CELL REPORTS 1996; 15:367-370. [PMID: 24178359 DOI: 10.1007/bf00232373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/1994] [Revised: 05/26/1995] [Indexed: 06/02/2023]
Abstract
Somatic embryos induced from callus cultures of lemongrass [Cymbopogon flexuosus (Nees) Wats.] on Murashige and Skoog medium supplemented with 5 mg/l of 2,4-D, 0.1 mg/l of NAA and 0.5 mg/l of Kn developed into plantlets when plated on a medium supplemented with 3 mg/l of BA, 1 mg/l of GA3 and 0.1 mg/l of NAA. The regeneration potential of callus was retained for more than 2 years on the nutrient medium supplemented with comparatively lower levels of growth regulators (2,4-D at 2 mg/l, NAA at 0.1 mg/l and Kn at 0.25 mg/l). Approximately 30-35 plantlets were produced after two months of culture per 100 mg of callus inoculated. Regenerants were transplanted into soil and transferred to the field for assessment of various morphological and biochemical characteristics. The results of 1 year of field trials showed that plants derived from somatic embryoids were more uniform in all the characteristics examined when compared with the field performance of plants raised through slips by standard propagation procedures. Thus, a procedure has been developed for high frequency long term plant production of lemongrass through in vitro methods.
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194
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Majumder PP, Das RN, Nayak S, Bhattacharya SK, Mukherjee BN. Genetic epidemiology of blood pressure in two Indian populations: some lessons. Hum Biol 1995; 67:827-42. [PMID: 8543295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A genetic epidemiological study of blood pressure was conducted in two contrasting populations: the Marwaris of Calcutta and the Hindu middle-caste agriculturists of Digha. The Marwaris are heavier and significantly more obese than the agriculturists. The prevalence of hypertension among the Marwaris (17%) is more than tenfold higher than that among the agriculturists (1.4%). Genetic analysis of blood pressure data using a path model indicates that blood pressure levels (adjusted and standardized for age, gender, education level, and disease status) are primarily determined by environmental factors, as measured by their effects on anthropometric characters. The observed familial resemblance of blood pressure levels in the two populations is primarily due to cultural rather than genetic inheritance. Genetic and familial effects on covariation between anthropometric measures of obesity and blood pressure levels are perhaps so strong that there is no residual genetic heritability of adjusted blood pressure levels.
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195
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Dhar PK, Kumar MR, Nayak S, Rao TR, Joseph A, Devi S, Kumari U, Bhat SM, Bhat KR. A rapid silver staining and destaining technique for the nucleolus organizer region. Biotech Histochem 1995; 70:302-3. [PMID: 9044659 DOI: 10.3109/10520299509108337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Silver staining of nucleolar organizing regions (NOR) is common, but a standard protocol is lacking. A modification of a rapid silver nitrate staining technique for NORs is presented here. Advantages of the modified technique include reliability, speed, cost and the fact that it can be carried out in the light.
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196
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Nayak S, Sen S. Rapid and stable propagation ofOrnithogalum umbellatum L. in long term culture. PLANT CELL REPORTS 1995; 15:150-153. [PMID: 24185675 DOI: 10.1007/bf01690274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/1994] [Revised: 05/11/1995] [Indexed: 06/02/2023]
Abstract
Callus cultures were raised from bulb scale segments ofOrinthogalum umbellatum L. (Liliaceae), on a Murashige and Skoog (1962) medium (MS) with 8 mg/l naphthaleneacetic acid (NAA). Bulbous shoots developed from calli after 2 months using MS medium with 2 mg/l NAA and 0.5 mg/l N(6) - benzyladenine (BA). Shoots were also induced directly from scales of regenerated bulb used as secondary explants on MS medium supplemented with 0.5 mg/l BA. Shoots developed roots in 1/2 - strength MS medium. Regenerants multiplied rapidly in 1/2-MS liquid medium. Chromosome instability was reduced in callus grown on 2 mg/l NAA compared to callus grown on 8 mg/l NAA. Callus retained regeneration potential for 5 years in this modified MS medium. The chromosome analysis of regenerants dervied from callus, even from long term culture of 5 years, revealed only diploid cells with normal karyotype comprising 2n=46 chromosomes. Stable nature of callus and regenerants were further confirmed by cytophotometry. This procedure can be applied for securing stable regenerants on a mass scale inO. umbellatum.
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197
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Puré E, Camp RL, Peritt D, Panettieri RA, Lazaar AL, Nayak S. Defective phosphorylation and hyaluronate binding of CD44 with point mutations in the cytoplasmic domain. J Exp Med 1995; 181:55-62. [PMID: 7528778 PMCID: PMC2191806 DOI: 10.1084/jem.181.1.55] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
CD44 is a cell surface adhesion molecule that plays a role in leukocyte extravasation, leukopoiesis, T lymphocyte activation, and tumor metastasis. The principal known ligand for CD44 is the glycosaminoglycan hyaluronate, (HA), a major constituent of extracellular matrices. CD44 expression is required but is not sufficient to confer cellular adhesion to HA, suggesting that the adhesion function of the receptor is regulated. We recently demonstrated that CD44 in primary leukocytes is phosphorylated in a cell type- and activation state-dependent fashion. In this study we demonstrate that serines 325 and 327 within the cytoplasmic domain of CD44 are required for the constitutive phosphorylation of CD44 in T cells. Furthermore, we demonstrate that cells expressing mutated CD44 containing a serine to glycine substitution at position 325 or a serine to alanine substitution at amino acid 327 are defective in HA binding, CD44-mediated adhesion of T cells to smooth muscle cells, as well as ligand-induced receptor modulation. The effect of these mutations can be partially reversed by a monoclonal anti-CD44 antibody that enhances CD44-mediated HA binding.
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198
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Nayak S, Pai KP, Pai KG. Neonatal cervical choristoma--a case report. INDIAN J PATHOL MICR 1994; 37 Suppl:S1. [PMID: 8613151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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199
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Phipps JH, John M, Nayak S. Comparison of laparoscopically assisted vaginal hysterectomy and bilateral salpingo-oophorectomy with conventional abdominal hysterectomy and bilateral salpingo-oophorectomy. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1993; 100:698-700. [PMID: 8080472 DOI: 10.1111/j.1471-0528.1993.tb14246.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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200
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Malde HM, Kedar RP, Chadha D, Nayak S. Dermoid mesh: a sonographic sign of ovarian teratoma. AJR Am J Roentgenol 1992; 159:1349-50. [PMID: 1442421 DOI: 10.2214/ajr.159.6.1442421] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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