Biomedical subjects
Publications and source records attributed to S Panyim.
The disulfide contents of human sperm heads, as measured by reduction to the sulfhydryls and subsequent alkylation with 14C-iodoacetamide, increase about 2-fold during the sperm passage from the caput to caudal epididymides. Majority of the increased disulfides resides in the human protamine fractions.
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Optimal conditions for prolonged in vitro synthesis of RNA in isolated chicken liver nuclei have been described. It is shown by incorporation of gamma32P-GTP into RNA, analysis of the product on sucrose density gradient, and digestion with alkaline phosphatase and ribonuclease A that there is reinitiation of RNA synthesis. Polynucleotide kinase activity has been ruled out as explanation for the incorporation of gamma32P-GTP. alpha-Amanitin inhibits RNA synthesis by about 50%. Nuclei prepared from estradiol-treated chicks have twice the RNA synthesis activity as the controls. RNA is synthesized in the presence of Hg-UTP and the mercurated product separated by affinity chromatography on sulfhydryl-Sepharose column under stringent conditions. Vitellogenin mRNA sequences are measured by hybridization with DNA complementary to vitellogenin mRNA. Estradiol treatment leads to a 10-fold increase in vitellogenin mRNA sequences.
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A method is described, which is capable of fractionating histones obtained from any animal source into five major groups. Although the method is based on procedures initially developed by E. W. Johns (1964), involving differential solubility in solutions of acids and of ethanol, it gives a cleaner separation and possesses the considerable advantage that the starting material is whole histone rather than a nucleoprotein preparation.
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The polymerase chain reaction (PCR) procedure using a primer set derived from a repetitive deoxyribonucleic acid (DNA) sequence specific to Plasmodium falciparum was used to detect parasite DNA in mosquitoes. In laboratory-infected mosquitoes, PCR could detect as few as 10 sporozoites in a dissected salivary gland and a single oocyst in a dissected midgut. The ability to detect P. falciparum DNA in wild-caught mosquitoes indicated an advantage of the PCR over enzyme-linked immunosorbent assay for the detection of Plasmodium sporozoites in mosquitoes with low-grade parasite infections.
The rapid manual ParaSight-F test for Plasmodium falciparum is an antigen capture test detecting trophozoite-derived histidine rich protein II, is simple and provides a definitive diagnosis within 10 min. Compared with 913 thick blood film examinations, the ParaSight-F test had 93.4% sensitivity and 98.2% specificity. Compared with 520 blood samples within the same study examined with the aid of the polymerase chain reaction, the ParaSight-F test had 91.6% sensitivity and 99.4% specificity. The ParaSight-F test could be a valuable diagnostic tool for falciparum malaria in any situation requiring rapid diagnosis in the absence of microscopical examination.
The swelling of human sperm head and the decondensation of the sperm chromatin were investigated using a microscopic observation and the increased binding of AMD as the probes. Incubation of the human spermatozoa with 1 mM DTT produced sperm head swelling within 30 min. Addition of soybean trypsin inhibitor or PMSF blocked the swelling induced by 1 mM DTT. The DTT induced a large increase in the binding of AMD to the spermatozoa, to the sperm head and to the triton X-100 treated spermatozoa. This increase in AMD binding was completely abolished by the presence of PMSF. These results suggested the participation of a sulfhydryl reducing agent and a proteolytic enzyme in the sperm head swelling and the chromatin decondensation. The simplicity of probing the chromatin decondensation with AMD binding offers a means to study kinetic and quantitative aspects of the process.