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Biomedical subjects

O Singh

Publications and source records attributed to O Singh.

43 records · Page 3Linked to original sources
PubMed1982

Comparative study of cholinesterase in two snails Pila globosa and Lymnaea acuminata.

Enzymatic activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was measured in the nervous and cardiac tissue of two snails Pila globosa and Lymnaea acuminata. Data on substrate specificity, enzyme kinetic constants and specific enzyme inhibitors indicated that, L. acuminata possessed both AChE and BuChE, while, P. globosa had only AChE. Pharmacological experiments carried out on isolated organs of the two snails indicated that isolated organs of P. globosa were sensitive to low doses of acetylcholine (ACh) and to relatively higher doses of butyrylcholine (BuCh). The responses elicited by ACh could be enhanced by eserine but that of BuCh could not be increased by ethopropazine which has been shown to be a specific inhibitor of BuChE in snails. Isolated hearts of L. acuminata on the other hand, were more sensitive to BuCh as compared to ACh. The BuCh effect was enhanced by ethopropazine while the effect of both ACh and BuCh increased by prior application of eserine. There is a correlation between the occurrence of the two types of cholinesterase (ChE) and the sensitivity of the isolated organs to a specific substrate of these enzymes suggesting a possible correlation between transmitters and cholinesterase system.

Acetylcholinesterase↗
PubMed1981

Clinical trial with CIBA 1906 in lepromatous leprosy.

Drug trial with CIBA 1906 was conducted in 50 cases of lepromatous leprosy who were intolerant to dapsone therapy. Drug was tolerated well and lepra reactions were infrequent and mild. Clinical improvement was seen in 72% cases whereas no appreciable change was detected in 28% cases. An average reduction of 0.4 in BI was detected in 62% cases, while remaining cases did not show any reduction in BI. No significant side effects were encountered during the study. Antibacterial activity of CIBA 1906 was not found superior to dapsone.

Adult↗
PubMed1978

Pharmacological studies on the molluscicidal activity of phorate on Pila globosa (Gastropoda).

Amongst heart, rectum and radula protractor muscles of Pila globosa, the heart showed a negative inotropic and negative chronotropic response while the rectum and radula protractor showed a positive tonotropic response to exogenously applied acetycholine (ACh). The anti-cholinesterase pesticide phorate substantially increased the response to ACh; at high doses it could also evoke cholinomimetic response from the heart. The anti-cholinesterase property of phorate gradually increased with an increase in its contact period to the tissue. The extent of alteration in ACh response caused by prior treatment with low and high doses of phorate were very similar, indicating that the efficacy of phorate is by and large time-dependent rather than dose-dependent. The effect of phorate remained irreversible even after prolonged washing. The mode of action of phorate has been discussed in the light of the above findings.

Acetylcholine↗
PubMedDate not supplied

Formulation and characterization of immunoreactive tetanus toxoid biodegradable polymer particles.

Poly lactide-co-glycolide and polylactide polymer particles entrapping immunoreactive tetanus toxoid (TT) were prepared with a view to developing a single shot controlled release vaccine formulation. Denaturation of TT by dichloromethane (DCM) during primary emulsification stage of particle formulation was minimized by incorporation of an optimal amount of rat serum albumin (RSA) in the internal aqueous phase. Incorporation of RSA as a stabilizer during the primary emulsification stage of polymer particle formulation protected the immunoreactivity of TT, enhanced its encapsulation efficiency and also led to uniform polymer particle formation. Use of sonication, both during primary and secondary emulsification processes, resulted in formation of nanoparticles whereas microparticles were formed when the secondary emulsion was carried out by homogenization. Immunoreactive TT particles made from different polymers incorporating stabilizers released antigen continuously for more than four months in vitro. Single injection of both type of particles encapsulating stabilized TT elicited anti-TT antibody titers in rats for more than five months, which was higher than that obtained with TT injected in saline. Anti-TT antibody titers in vivo were in accordance with the in vitro release characteristics of immunoreactive TT from the particles. Immune responses with hydrophobic polymer particles were better than those made using hydrophilic polymers. These results indicate the importance of protecting the immunoreactivity of TT during formation of polymer particles for sustained and improved antibody response.

Animals↗
PubMedDate not supplied

Bioneutralization capacity of the antibodies generated in women by the beta subunit of human chorionic gonadotropin (beta hCG) and beta hCG associated with the alpha subunit of ovine luteinizing hormone linked to carriers.

Data is presented on the bioneutralization capacity per unit immunoactivity of 30 serum samples of women immunized with the beta-subunit of human chorionic gonadotropin (beta-hCG) or beta hCG associated noncovalently with the alpha-subunit of ovine luteinizing hormone (alpha-oLH), to form a heterospecies dimer (HSD), which were linked to carriers. The bioassays utilized were inhibition of radioiodinated hCG binding to rat testicular receptors in vitro and the inhibition of hCG induced testosterone production in mice. In both assays, antisera of women immunized with the HSD had a bioactivity to immunoactivity ratio that was about 25% higher, on an average, than antisera of women immunized with beta-hCG, suggesting a better bioneutralization capacity of sera raised by the HSD in women.

Adult↗