Biomedical subjects
Publications and source records attributed to R Gopalakrishna.
To ensure reliable arginine estimation, other compounds giving positive results with Chinard's ninhydrin reaction were removed by simple ion-exchange chromatography. Eluted arginine was converted to ornithine by arginase and estimated using Chinard's ninhydrin reaction. Plasma arginine level in adults was in the range 56--98 mumol/l, and urine arginine in the range 0.58--1.77 mg/day.
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Occurrence and features of 130 suicide cases were studied in a culturally distinct community, Goa (India), which was isolated from mainland for over 450 years records obtained from the police and information collected from close relatives of the deceased were analyzed retrospectively. It was noted that cultural and religious factors continue to play an important role in suicidal behaviour in India. The rate was higher for males as compared with females and was greater in joint family than in nuclear family. Similarly, married persons of both sexes had a higher frequency. Ethnically the rate among Hindus was higher than among Christians. Mental illness constituted a major cause of suicide, followed by domestic conflicts. An interesting feature observed in the study was that more persons commit suicide in their own birth place and near their own homes.
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BACKGROUND: The aim of this study is to see the effect of interferon beta (IFN-beta) on cell proliferation and the protein kinase C (PKC) signaling pathway. METHODS: Proliferation of cultured human retinal pigment epithelium (RPE) cells, with various concentrations of IFN-beta, and with or without 3% fetal calf serum (FCS), was assessed by cell counting. Effects of short (3 h) or prolonged (48 h) exposure of RPE cells to natural human IFN-beta were assessed by (3)H-thymidine uptake. Cytosolic and membranous PKC activity over time in cells treated with IFN-beta and calphostin C was also measured. RESULTS: IFN-beta inhibited the increased proliferation by FCS in the prolonged-exposure assay. The PKC inhibitor calphostin C also showed an inhibitory effect on RPE cell growth and (3)H-thymidine uptake in the chronic exposure with FCS. Short treatment with IFN-beta had no inhibitory or stimulatory effect on (3)H-thymidine uptake. Cytosolic and membranous PKC activity was strongly upregulated after short IFN-beta exposure but returned to original levels after 1 h. PKC activity was downregulated both in the cytosol and membrane after 24 or 48 h. CONCLUSION: IFN-beta inhibited RPE proliferation in vitro and the effect is mediated by upregulation of the PKC pathway.
Thalidomide was synthesized in 1954 in erstwhile West Germany and marketed as a sedative in over 46 countries until the early 1960s. Owing to serious teratogenic effects, the drug was withdrawn from the market in 1961. A chance observation suggested the utility of thalidomide in erythema nodosum leprosum (ENL). After many controlled and uncontrolled trials were published, the World Health Organization recommended its use in ENL. The Food and Drug Administration, USA approved it for use in ENL in July 1998. Only established and well-defined studies conducted to substantiate the efficacy of thalidomide have been included in this review. Thalidomide is considered the drug of choice for the treatment of ENL, but for other conditions, it is recommended only when resistance to the currently available form of therapy is encountered. Once the anti-inflammatory, immuno-modulatory, anti-TNF-alpha and anti-angiogenic properties of thalidomide were discovered, it was also tried in AIDS and related wasting, apthous ulcers, microsporidiosis and Kaposi's sarcoma. Thalidomide has no clinical place as an immunosuppressant in solid organ transplantation. However, it has a therapeutic role in graft-verus-host-disease. Among the dermatological conditions, thalidomide has been found to be effective in systemic lupus erythematosus, discoid lupus erythematosus, actinic prurigo and prurigo nodularis. Used correctly, it is a safe and effective medicine (except for its teratogenic potential and delayed neuropathy) in a variety of disease conditions.
Calmodulin binds quantitatively to phenyl-Sepharose through its Ca2+-induced hydrophobic binding region. Troponin C and S-100 protein, as well as several other proteins present in rat tissues, also bind to phenyl-Sepharose in a Ca2+-dependent manner. While the Ca2+-dependent binding of calmodulin to phenyl-Sepharose is not altered appreciably by monovalent cations, they do appear to compete for Ca2+ binding to most of the other proteins, including S-100 protein, which exhibit Ca2+-induced interaction with phenyl-Sepharose. The selective elution of these proteins from the phenyl-Sepharose column can be achieved with a 0.5 M concentration of monovalent cations such as K+, Na+, and NH4+ in the presence of a low (100 microM) Ca2+ concentration. Calmodulin-binding proteins associated with calmodulin in crude cell extracts can prevent the interaction of calmodulin with the phenyl-Sepharose, resulting in low recoveries of calmodulin from these tissues. The majority of these interfering proteins are heat labile so that heat treatment (boiling) of the cell extract for a limited time (5 min) negates any binding of these proteins to calmodulin and allows the quantitative recovery of calmodulin by hydrophobic interaction chromatography. This procedure allows the rapid and quantitative recovery of highly purified calmodulin from both cytosolic and Triton X-100-solubilized particulate fractions prepared from various rat tissues. Calmodulin isolated in this manner can be accurately and reliably quantitated by direct protein determination with Coomassie brilliant blue dye or fluorescamine or by the cyclic nucleotide phosphodiesterase stimulation assay.