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Biomedical subjects

S Jain

Publications and source records attributed to S Jain.

At least 19 recordsLinked to original sources
PubMed1992

Crystal and molecular structure of the alternating dodecamer d(GCGTACGTACGC) in the A-DNA form: comparison with the isomorphous non-alternating dodecamer d(CCGTACGTACGG).

The crystal structure of the alternating dodecamer d(GCGTACGTACGC) (5'-GC) has been determined to a resolution of 2.55A using oscillation film data. The crystals belong to space group P6(1) 22, a = b = 46.2A, c = 71.5A with one strand in the asymmetric unit, and are isomorphous with a previously described non-alternating dodecamer, d(CCGTACGTACGG) (5'-CC). Refinement by X-PLOR/NUCLSQ gave a final R factor of 14.2% for 1089 observations. The molecule adopts the A-DNA form. The interchange of the terminal base pairs in the two dodecamers results in differences in the intermolecular contacts and may account for the differences in the bending. This dodecamer shows an axial deflection of 30 degrees, in the direction of the major groove compared to 20 degrees in 5'-CC and may be a consequence of additional contacts generated in 5'-GC by the interchange of end base pairs. The high helical axis deflection appreciably influences the local helical parameters. The molecule exhibits relatively high inclination angles, and has a narrow major groove. The helical parameters when described relative to the dyad-related hexamer halves of the molecule give more reasonable values. The crystal packing, local helical parameters, torsion angles, and hydration are described and also compared with the non-alternating 5'-CC dodecamer.

Amides↗
PubMed1992

Sodium benzoate in the treatment of acute hepatic encephalopathy: a double-blind randomized trial.

A prospective randomized double-blind study was conducted to evaluate the efficacy of sodium benzoate in the treatment of acute portal-systemic encephalopathy. Seventy-four consecutive patients with cirrhosis or surgical portasystemic anastomosis and hepatic encephalopathy of less than 7 days duration were randomized to receive lactulose (dose adjusted for 2 or 3 semiformed stools/day) or sodium benzoate (5 gm twice daily). Assessment of response included mental status, asterixis, arterial ammonia level, electroencephalogram and number-connection test. Each was given a score between 0 and 4+. A portal-systemic encephalopathy index was calculated with these scores. Visual, auditory and somatosensory evoked potentials and a battery of psychometric tests for intelligence and memory were also performed to assess improvement. Thirty-eight patients received sodium benzoate; 36 took lactulose. Thirty patients (80%) receiving sodium benzoate and 29 (81%) receiving lactulose recovered; the remaining patients died. Improvement in portal-systemic encephalopathy parameters occurred in both treatment groups and was similar (p greater than 0.1). Electroencephalogram and evoked potentials were not as helpful as mental status in assessing of recovery. Psychometric test scores remained abnormal after recovery of mental status (21 to 42 days) and were probably too sensitive for monitoring of these patients. The incidence of side effects was similar in the two treatment groups. The cost of lactulose for one course of therapy was 30 times that of sodium benzoate. We conclude that sodium benzoate is a safe and effective alternative to lactulose in the treatment of acute portasystemic encephalopathy.

Acute Disease↗
PubMed1992

Development of a transformation system for the thermophilic fungus Talaromyces sp. CL240 based on the use of phleomycin resistance as a dominant selectable marker.

A transformation system for the thermophilic cellulolytic fungus Talaromyces sp. CL240 has been developed, using the phleomycin resistance gene from Streptoalloteichus hindustanus (Sh ble) as a dominant selectable marker. The plasmids (pAN8-1 and pUT720) carrying the Sh ble gene under the control of the Aspergillus nidulans glyceraldehyde-3-phosphate dehydrogenase (gpd) promoter, allowed selection of phleomycin-resistant transformants. A new promoter sequence cloned from chromosomal DNA of Trichoderma reesei (pUT737) was also able to drive efficient expression of the Sh ble gene in Talaromyces sp. CL240, resulting in the selection of transformants that were highly resistant to phleomycin.

Drug Resistance, Microbial↗
PubMed1992

Ki-ras oncogene activation in preinvasive pancreatic cancer.

Activation of the Ki-ras oncogene by specific point mutations at codon 12 occurs at a remarkably high frequency in pancreatic ductal adenocarcinoma and is likely to be an important event in the pathogenesis of this cancer. To determine whether ras activation also occurs in noninvasive proliferative lesions of the pancreas, a series of cases of ductal papillary hyperplasia, intraductal papillary neoplasia, and intraduct extensions of ductal adenocarcinoma were examined for activating mutations of Ki-ras at codons 12, 13, and 61 using polymerase chain reaction amplification. Specific mutations at Ki-ras codon 12 were found in 5 of 6 cases (83%) of intraduct extensions of carcinomas and in 12 of 16 (75%) invasive carcinomas. In cases with both intraductal and invasive components, the same mutation was identified in each. No mutations were found in 5 intraductal papillary neoplasms and 9 cases of ductal papillary hyperplasia. The authors conclude that Ki-ras activation at codon 12 is important in the tumorigenesis of ductal adenocarcinoma of the pancreas but is not required in the pathogenesis of ductal papillary hyperplasia or intraductal papillary neoplasm.

Adult↗
PubMed1992

Climate and admissions for mania in the tropics.

Seasonality of admissions for mania has been commonly reported. Most reports are from temperature zones. We analyzed admissions for mania covering a 9 year period and looked for any seasonal trends using existing methods. No seasonal variation was found. The hospital lies in the tropical zone with a relatively constant climate. This may influence the seasonal pattern of relapses in affective disorder.

Adult↗
PubMed1992

Time dependent therapeutic effects of single electroconvulsive therapy (ECT) in endogenous depression.

The present study was addressed to test the hypothesis of time dependent effects of a single ECT in endogenous depression. In a randomized, prospective and double blind controlled comparison 12 patients received only one true modified ECT followed by five sham ECTs on alternate days. They responded as well as the control group of 12 patients who received six true ECTs on alternate days. The Hamilton Rating Scale for Depression and a global rating scale for depression were used to monitor therapeutic response. The therapeutic effects of ECT were time dependent developing during the second week of the study period.

Adult↗
PubMed1992

Sister-chromatid exchanges are increased in epileptics, but not by sodium valproate.

Sister-chromatid exchange (SCE) frequency has been studied from peripheral blood lymphocyte cultures of 21 patients with epilepsy on sodium valproate, 20 patients who had not started therapy (untreated) and 20 normal healthy controls. Treated and untreated patients with epilepsy were observed to have higher SCE frequencies (mean 9.05 and 9.82 respectively) than healthy controls (mean 4.8; P < 0.001). There was no significant difference in SCE frequency between treated and untreated patients. This suggests that the disease itself may be associated with an increased frequency of SCEs.

Adolescent↗
PubMed1992

Protein-peptide interactions as probed by tryptophan fluorescence: serum albumins and enkephalin metabolites.

Binding of Leu-enkephalin and the enkephalin metabolite, tyrosine-glycine-glycine (TGG), to bovine serum albumin (BSA) was studied as a model to investigate protein peptide interactions. TGG and Leu-enkephalin quench the tryptophyl fluorescence of BSA. Stern-Volmer quenching constants were typically in the range of 40 to 300 M-1, depending on the experimental conditions. The addition of Cu(II) or Ni(II) did not change the quenching constant, indicating that TGG does not compete for the metal binding sites on BSA. From fluorescence quenching studies with TGG, tyrosyl-glycine, tyrosine and glycyl-glycine, it was concluded that the presence of the tyrosine residue is required for the observed quenching. The phenolic group in tyrosine accounted for the quenching mechanism because phenol was efficient in quenching BSA fluorescence, whereas phenylalanine had no detectable effect. A large solvent isotope effect on the quenching constant of phenol and TGG with BSA strongly suggests an active role of the -OH functionality in the quenching mechanism.

Amino Acid Sequence↗
PubMed1992

Inoculation lupus vulgaris.

An 11-years-old girl with lupus vulgaris on the right buttock following inoculation is described. The diagnosis was formed by the history, morphological characteristics, Mantoux test, histopathology, and was supported by an affirmative response to short course intensive chemotherapy (6 months). This route of infection acquires special significance with the worldwide-spread of HIV infection.

BCG Vaccine↗
PubMed1992

Tuberous sclerosis and spina bifida occulta.

An interesting occurrence of tuberous sclerosis and spina bifida occulta is described, highlighting their unique and previously undescribed association in a 5-year-old boy.

Child, Preschool↗
PubMed1992

Seasonal relapses in affective disorder in the Tropics: a prospective follow-up of 12 patients.

Seasonal relapses of affective disorder are known. We report 12 patients who had season-linked relapses during a prospective follow-up period of 4 years. There were both winter and summer relapses of mania and depression. The centre is in the tropical zone, with lesser variation of sunshine and temperature than in more extreme latitudes. This may inference the pattern of relapse in affective disorder. Differences in relapses between tropical and temperate zones need to be investigated.

Adult↗
PubMed1992

Subacute toxicity of pentavalent antimony compounds in rats.

A subacute toxicity study of pentavalent antimony (Sb) compounds, sodium stibogluconate (SSG) and meglumine antimoniate (MA) was carried out in rats. Three groups of 10 rats each were treated with saline (control group), 300 mg Sb kg-1 d-1 or 900 mg Sb kg-1 d-1 of SSG for 30 d. A parallel study of similar type was conducted for MA. Compared with controls, drug-treated rats showed an impairment of feeding habits and retardation of weight gain (P less than 0.01) during the treatment period. In both SSG- and MA-treated rats there was a dose-related reduction in haemoglobin concentration (P less than 0.001), and hematocrit (P less than 0.001). Red cell count was reduced in SSG-treated rats only. Both drugs, however, significantly raised the white cell count (P less than 0.05). These changes were more pronounced with SSG them with MA. There was no change in MCV, MCH and MCHC. SSG, 900 mg Sb kg-1 d-1, significantly raised AST (P less than 0.005), ALT (P less than 0.01) and alkaline phosphatase activity (P less than 0.01). SSG-treated rats also had raised BUN (P less than 0.01) and creatinine (P less than 0.001), but no significant change in bilirubin levels. MA significantly raised AST (P less than 0.01), ALT (P less than 0.01), BUN (P less than 0.001) and serum creatinine levels (P less than 0.001), but had no appreciable effect on bilirubin and alkaline phosphatase levels. Both SSG and MA decreased blood glucose levels (P less than 0.01) and induced proteinuria.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1992

Dystrophin test in differential diagnosis of childhood muscular dystrophies.

Two cases of childhood muscular dystrophy are described. One of them had clinical features suggestive of Emery-Dreifuss muscular dystrophy and the other with some features of Prader-Willi syndrome, besides proximal muscle weakness. Muscle biopsy from both cases revealed a clear abnormality of dystrophin, and were diagnosed as having Duchenne muscular dystrophy (DMD) by immunofluorescence examination; that is, absent dystrophin at the membrane of the muscle fibers. The clinical spectrum of DMD-related myopathies and the importance of dystrophin testing in childhood muscular dystrophies is discussed.

Biopsy↗
PubMed1992

Seroepidemiology of viral infections among intravenous drug users in northern California.

Intravenous drug users are frequently exposed to parenterally transmitted viral infections, and these infections can spread to the general population through sexual activity. We investigated the prevalence of serologic markers for human immunodeficiency virus type 1 (HIV-1), human T-cell lymphotropic virus type I/II (HTLV-I/II), hepatitis B virus (HBV), and hepatitis C virus (HCV) in intravenous drug users and their sexual contacts. Of 585 drug users from northern California tested for these serologic markers, 72% were reactive for the antibody to HCV, 71% for the antibody to hepatitis B core antigen, 12% for HTLV-I/II antibodies, and 1% for the HIV-1 antibody. The prevalence of serologic markers for these four viruses correlated with the duration of intravenous drug use, the ethnic group, and the drug of choice. More than 85% of subjects infected with either HCV or HBV were coinfected with the other virus. All persons reactive to HTLV-I/II antibodies had antibodies for either HBV or HCV. Of 81 sexual contacts tested, 17% had evidence of HBV infection while only 6% were reactive for HTLV-I/II antibodies and 4% for the antibody to HCV. None of this group was infected with HIV-1. We conclude that HTLV-I/II and HCV are inefficiently transmitted to sexual contacts while HBV is spread more readily. Programs designed to discourage the sharing of drug paraphernalia, such as needle and syringe exchanges, should decrease the risk of parenterally spread viral infections in intravenous drug users and thus slow the spread of these infections to the general population.

Adult↗