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Biomedical subjects

V Srinivasan

Publications and source records attributed to V Srinivasan.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

If we were supposed to take vitamins, wouldn't they grow on trees?

Vitamin E supplementation may not be as innocuous as previously believed. A dose relationship between vitamin E and all-cause mortality may exist, beginning at 150 IU per day. Mortality risk was minimally but statistically higher for doses of Vitamin E 1000 IU/d or greater compared with placebo. Further controlled trials using both natural and synthetic forms of Vitamin E are warranted to determine the true effects.

Journal Article↗
PubMedDate not supplied

Metabolic inhibitors, elicitors, and precursors as tools for probing yield limitation in taxane production by Taxus chinensis cell cultures.

Inhibition of biosynthetic enzymes and translation and translocation processes, elicitation, and precursor feeding were used to probe biosynthetic pathway compartmentation, substrate-product relationships, and yield limitation of the diterpenoid taxanes in cell cultures of Taxus chinensis (PRO1-95). The results suggest the following: (i) the source of isopentenyl pyrophosphate in taxane production is likely plastidic rather than cytoplasmic; (ii) baccatin III may not be a direct precusor of Taxol (Taxol is a registered trademark of Bristol-Myers Squibb for paclitaxel); (iii) baccatin III appears to have cytoplasmic and plastidic biosynthetic components, while Taxol production is essentially plastidic; and (iv) arachidonic acid specifically stimulates Taxol production but does not have a significant effect on baccatin III yield. Semiempirical mathematical models were used to describe these results and predict potential yield-limiting steps. Model simulations suggest that, under current operating conditions, Taxol production in Taxus chinensis (PRO1-95) cultures is limited by the ability of the cells to convert phenylalanine to phenylisoserine rather than by the branch-point acyl transferase. This result is supported by the lack of improvement of Taxol yield by feeding phenylalanine or benzoylglycine. The methods described in this article, while specifically expanding our knowledge of taxane production in PRO1-95 cultures, could be generally useful in investigating complex aspects of secondary metabolic pathways in plant cell cultures, especially when details of the pathway and compartmentation are sparse.

Alkaloids↗
PubMedDate not supplied

Non-recurrent laryngeal nerve: identification during thyroid surgery.

The non-recurrent course of the inferior laryngeal nerve is a rare anomaly. The incidence varies from 0.3 to 4% on the right side. It is extremely rare on the left side. The awareness of such an anomaly is essential as the risk of damage to the nerve is higher during thyroid surgery. Two cases of non-recurrent laryngeal nerve are reported, and the embryology and method of identification are discussed.

Adult↗
PubMedDate not supplied

A consideration of previously uncharacterized fowl poxvirus unidirectional and bidirectional late promoters for inclusion in homologous recombinant vaccines.

Because of the limited analysis of fowl poxvirus (FPV) promoters, expression of foreign proteins by recombinant FPV has usually been directed by heterologous vaccinia virus or synthetic poxvirus promoters. Thus, the impact of completely homologous recombinant virus vaccines has yet to be realized by the poultry industry. In an effort to increase the availability of such transcriptional regulatory elements, the modulation of gene expression by six previously uncharacterized FPV late promoters was examined. To simplify this comparison, each promoter region was separately coupled to the same reporter gene (lacZ) in individual plasmid constructs, and their activities in transfected, virus-infected cells were monitored. In each of the four selected unidirectional transcriptional regulatory elements as well as a 30-base pair representative of the bidirectional promoter region, the predicted temporal specificity of expressing at late stages of virus replicative cycle was verified. Stable lacZ gene transcripts arising from each plasmid varied less than threefold in quantity, whereas the amounts of beta-galactosidase product ranged within a 130-fold interval. Only the promoter that naturally regulates expression of the A type inclusion body protein gene directed production of beta-galactosidase at a level comparable with that associated with the strong vaccinia virus P11 promoter. Because one of the remaining unidirectional transcriptional regulatory elements, P174, was only 2.4-fold less efficient, both of these promoters, P174 and P190, should be satisfactory for directing the expression of poultry pathogen genes inserted into the genomes of FPV recombinant vaccines.

Animals↗
PubMedDate not supplied

Adult onset celiac disease in north India.

INTRODUCTION: Informations on celiac disease among Indian adults is scarce. With the availability of improved and more accessible diagnostic tools for celiac disease, the disease is being more frequently recognized among the adults. Therefore, a retrospective analysis of duodenal biopsies were performed to identify adult celiac disease among Indian patients. MATERIAL AND METHODS: A retrospective analysis of the patients, who had villous atrophy on duodenal biopsy between February, 1997 to June 2001, was performed. The clinical presentation, laboratory parameters, treatment and follow up details of patients diagnosed as adult onset celiac disease were analysed. Diagnosis of celiac disease was established in these patients as per ESPGAN criteria. RESULTS: There were 68 duodenal biopsies during the study period. Thirteen (10 were under 15 years of age and 3 had followup biopsy) biopsies were excluded. Eleven (20%) out of 55 patients with villous atrophy in their duodenal biopsy satisfied the ESPGAN criteria for the diagnosis of celiac disease. The age at the time of diagnosis ranged from 15-56 years (mean 36.8 years). Male to female ratio was 5:6. Chronic diarrhea (99%) was the most common presentation followed by weight loss (88%) and anemia (66%). Only one patient had refractory iron deficiency anemia (11%). Histopathological examination showed, subtotal villous atrophy in 6 patients and partial villous atrophy in 5. Nine out of 11 patients had raised concentration of IgA antigliadin antibody. Two patients also had raised concentration of antiendomysial antibody. All of them showed favorable clinical response to Gluten free diet. CONCLUSION: Coeliac disease is considered rare in the tropics. Our study shows that this disease may not be as infrequent as is thought.

Adolescent↗
PubMedDate not supplied

The pineal gland: its physiological and pharmacological role.

Our perception of pineal gland function has attained new dimensions during the last decade. The gland is active throughout the life of an individual and secretes melatonin, the major pineal hormone, and many indoles and polypeptides. The secretion of pineal gland is regulated not only by sympathetic nerve fibers but by other central pinealopetal projections also. Many neurotransmitter-receptor sites have been identified recently in the pineal gland. The gland plays an established role in controlling reproduction and is involved in the control of sexual maturation. It has a major influence on the circadian organization of vertebrates including human beings. The hormone melatonin has a potential therapeutic valve in treating disorders that are associated with biological rhythm disturbances like sleep disorders, "jet lag" phenomena and affective disorders. The gland is actively involved in the mechanisms controlling sleep-wakefulness cycle and human mood disorders. It actively participates in the neuroendocrine mechanism controlling stress and acts even as an oncostatic gland. The pineal gland may be considered an "equilibrating-tranquilizing gland" contributing to longevity.

Animals↗