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Biomedical subjects

V Ramesh

Publications and source records attributed to V Ramesh.

At least 271 records · Page 15Linked to original sources
PubMed1985

1H n.m.r. studies of insulin. Assignment of resonances and properties of tyrosine residues.

The assignment of the aromatic 1H n.m.r. resonances of the four tyrosine residues of bovine 2-zinc insulin is reported, based on double resonance techniques, use of Hahn spin echo pulse sequences and examination of specific derivatives nitrated at tyrosines A14 and A19 as well as des-(B26-B30)-insulin. Titration curves of the four tyrosine residues show that residues A14 and B16 have normal pK' values of 10.3-10.6 in solution, consistent with their accessibility to solvent in monomer and dimer in the crystal. Tyrosine residues A19 and B26 have pK' values of 11.4 and exhibit other features in their titration curves that are consistent with limited accessibility to solvent and a nonpolar environment. The meta protons of residues B16 and B26 both observe the titration of a nearby tyrosine residue, probably A19. Interpretation of the n.m.r. data obtained in solution is consistent with the crystallographic data for the monomer and dimer obtained on insulin crystals [Blundell, Dodson, Hodgkin & Mercola (1972) Adv. Protein Chem. 26, 279-402].

Chemical Phenomena↗
PubMed1984

Cysticercosis.

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Cysticercosis↗
PubMed1983

Onychomycosis.

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Adolescent↗
PubMed1983

Pattern of leprosy in a city hospital.

A total of 1327 leprosy patients attending one of the leading Delhi hospitals from 1977 to 1982 were reviewed. Leprosy, as such, is not a prominent disease in Delhi, but an influx of patients from the adjoining endemic states of Uttar Pradesh and Bihar has created a challenge because of increased construction activities for the Asiad '82. A relatively large number of patients were recorded during 1980. Most of the patients were unskilled workers. The usual preponderance of males over females was fairly explicit. Patients of low socioeconomic status were seen more frequently than those of higher socioeconomic status. The disease was found in the age group of 20-30 years and, in most cases, the age at onset was between 20-29 years. Infectious cases belonging to the borderline-to-lepromatous (BB-BL-LL) groups were reported more frequently than tuberculoid (TT-BT) cases. A suggestion is made to incorporate neuritic and indeterminate cases in the five-group classification in order to cover the total spectrum of the disease.

Adult↗
PubMed1979

A perfused canine right bundle branch-septal model for electrophysiological studies.

UNLABELLED: As documented in the literature, isolated ventricular muscle preparations perfused with protein-free media become edematous and deteriorate. We hypothesized that the addition of colloid oncotic pressure to the perfusion medium might affect favorably the electrical characteristics and survival of an isolated right bundle branch-septal muscle preparation perfused via the anterior septal artery. Perfusion with protein-free Tyrode solution produced edema formation and a loss of transmembrane potential of Purkinje and muscle cells within 5.9 +/- 0.40 h. Addition of bovine albumin, 4 g/100 ml, to the Tyrode solution or perfusion with horse serum greatly reduced the formation of edema. Furthermore, intact electrical activity continued for more than 9 +/- 0.31 h (P less than 0.001). The preparations showed a greater diastolic potential and action potential amplitude during perfusion than during superfusion with Tyrode solution. IN CONCLUSION: 1) a viable, perfused septal muscle preparation was developed for electrophysiological studies, and 2) colloid oncotic pressure in the perfusion medium is essential to preserve the integrity of the capillary circulation and to eliminate edema formation and tissue death.

Animals↗
PubMedDate not supplied

Ethanolic leaf extract of neem (Azadirachta indica) inhibits buccal pouch carcinogenesis in hamsters.

We evaluated the chemopreventive effects of ethanolic neem leaf extract in the initiation and post-initiation phases of 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. The frequency of bone marrow micronuclei as well as the concentrations of lipid peroxides, ratio of reduced to oxidized glutathione (GSH/GSSG), and the activities of the GSH-dependent enzymes glutathione peroxidase (GPx) and glutathione-S-transferase (GST) in the buccal pouch, liver and erythrocytes were used as biomarkers of chemoprevention. All the hamsters painted with DMBA alone for 14 weeks developed buccal pouch carcinomas that showed diminished lipid peroxidation and enhanced antioxidant status associated with increased frequencies of bone marrow micronuclei. In the liver and erythrocytes of tumour-bearing animals, enhanced lipid peroxidation was accompanied by compromised antioxidant defences. Administration of ethanolic neem leaf extract effectively suppressed DMBA-induced HBP carcinogenesis as revealed by the absence of tumours in the initiation phase and reduced tumour incidence in the post-initiation phase. In addition, ethanolic neem leaf extract modulated lipid peroxidation and enhanced antioxidant status in the pouch, liver and erythrocytes and reduced the incidence of bone marrow micronuclei. The results of the present study, demonstrate that ethanolic neem leaf extract inhibits the development of DMBA-induced HBP tumours by protecting against oxidative stress.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

Western blot analysis of humoral immune response to Leishmania donovani antigens in patients with post-kala-azar dermal leishmaniasis.

Sera from 32 Indian patients with post-kala-azar dermal leishmaniasis (PKDL) were examined for antibodies by immunoblot analysis using an antigen extract of Leishmania donovani. The study revealed that the humoral immune response in PKDL patients was quite distinct compared to that in kala-azar patients. Antibodies to 3 antigens of L. donovani (molecular sizes 110, 65 and 38-42 kDa) were predominant in a majority (78%) of PKDL patients. The most important finding was the consistent recognition of 2 parasite antigens (of 110 and 65 kDa) by PKDL sera; antibodies to the 110-kDa antigen were detectable in 97% of cases, while antibodies to the 65-kDa antigen were detectable in 100% of cases that were examined. None of the 18 cases of leprosy, 10 of vitiligo, or the 30 healthy persons included in the study showed antibodies to these 2 antigens. Thus Western blot analysis provided a highly sensitive test for PKDL patients. Further, it led to the identification of 2 parasite antigens (110 and 65 kDa) that elicit an antibody response in 97-100% of PKDL patients. Purified or recombinant versions of these proteins deserve consideration as potential target antigens in development of simpler, highly specific and sensitive serodiagnostic tests for PKDL.

Adolescent↗
PubMedDate not supplied

Role of medial preoptic area beta adrenoceptors in the regulation of sleep-wakefulness.

The role of the medial preoptic area (mPOA) beta adrenergic receptors in the regulation of sleep-wakefulness (S-W) was investigated in this study. S-W was assessed on the basis of polygraphic recording of EEG, EMG and EOG in free moving rats. Intracerebral microinjection of beta agonist, isoproterenol, into the mPOA produced arousal. The study was also conducted on another set of rats in which noradrenergic (NE) innervation to the mPOA was destroyed by injecting 6-hydroxydopamine into the ventral noradrenergic bundle, in the brain stem. Local application of isoproterenol, into the mPOA, in these animals, did not produce any significant change in S-W. Thus, the increase in awake period obtained on isoproterenol administration was the result of its action on the presynaptic NE terminals. Possible involvement of other responses in the isoproterenol induced increase in wakefulness, is discussed.

Adrenergic beta-Agonists↗
PubMedDate not supplied

A study of cutaneous tuberculosis in children.

Sixty-three children out of a total of 199 patients seen with cutaneous tuberculosis during a 7-year period were included in this study. Culture was positive in only four, and the diagnosis was based on clinical examination, tuberculin reaction, histopathology, and response to antitubercular therapy. Forty had lupus vulgaris (LV) and 23 scrofuloderma (SD). The lower half of the body was predominantly affected in those with LV, and keratotic and hypertrophic forms were frequently encountered. LV planus mainly affected the face. Ulcerative and atrophic types of LV were infrequent. Extensive lesions in three children led to disfiguring scars and contractures. Scrofuloderma often involved the cervical group of lymph nodes followed by the inguinal, submandibular, and axillary groups. As compared to skin tuberculosis in adults, regional lymph node involvement in LV was more common, and a combination of both LV and SD was less frequent in children. No difference in clinical presentation could be detected between the BCG vaccinated and unvaccinated children. Tuberculous infection either in the lungs or the bones was present in eight children. An HIV test done in five patients with widespread lesions was negative. Irregular therapy or late diagnosis leading to serious complications, inadequate parental or community support, and lack of awareness among practitioners are the problems to be remedied.

Adolescent↗