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Biomedical subjects

A Mohandas

Publications and source records attributed to A Mohandas.

At least 19 recordsLinked to original sources
PubMed2005

Copper-induced changes in tissue enzyme activity in a freshwater mussel.

Changes in enzyme activity levels are of great diagnostic value. Lysosomal membrane is often the target of injury by xenobiotics, resulting in destabilization. Variations in the activity of acid phosphatase (ACP) a marker enzyme, in gills and hepatopancreas of the freshwater mussel Lamellidens corrianus (Lea) exposed to different concentrations of copper for 24, 120, and 168 h are discussed. The aim was to determine if the metal caused any variation in enzyme activity in the two tissues studied and, if so, whether the length of exposure had any influence on enzyme activity. ACP activity was determined as described in Sigma Technical Bulletin No. 104 and expressed as micromoles of p-nitrophenol liberated per milligram of protein per hour. Both concentration of the metal and length of exposure were found to influence enzyme activity. Higher concentrations of metals are assumed to induce stress proteins like metallothioneins.

Acid Phosphatase↗
PubMed1991

A prominent antigenic surface polypeptide involved in the biogenesis and function of the vaccinia virus envelope.

Polypeptides of the vaccinia virus envelope exposed on the surface were identified by means of sulfo-N-hydroxysuccinimidobiotin as a surface tag. Among surface expressed polypeptides is the 35-kDa antigen, previously designated Ag35. Both monoclonal (mAb) and monospecific affinity pure antibodies directed against Ag35 neutralized vaccinia infectiousness, indicating that this prominent surface antigen has a function during early virus-host cell interactions. The binding of several monoclonal antibodies to various regions of Ag35 was tested by reacting CNBr fragments, derived from the polypeptide, employing Western blotting. All mAbs tested reacted with the same region of Ag35. Estimation of the molecular weights (MW), based on migration of the CNBr peptides in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, revealed that those partial digestion products which contained a proline-rich 99 amino acid limit digest fragment were present at a position approximately 12.5 kDa larger than that predicted from the DNA sequence. By contrast, partial and limit digest products lacking the proline-rich fragment migrated to the MW position expected from the length of the DNA sequence. This observation demonstrates that departure from a predicted 22.3 kDa to an anomalous MW of Ag35 is conferred by the proline-rich peptide. The surface location of Ag35 was confirmed by immune electron microscopy. In a competition test the binding specificity of mAb and affinity-purified antibodies at the surface of virions could be demonstrated. Evidence for an association of Ag35 with the virus envelope at various stages during biogenesis of vaccinia was obtained by immune electron microscopy of whole mounts and thin sections. Presence of Ag35 as an early component of immature and mature virions, probably residing in the bilayer membrane structure was detected. A distinction can, therefore, be made between Ag35 and several other vaccinia envelope polypeptides which are synthesized as late functions and added during late stages of envelope assembly.

Animals↗
PubMed1990

Number and types of hemocytes in Sunetta scripta and Villorita cyprinoides var. cochinensis (Bivalvia), and leukocytosis subsequent to bacterial challenge.

The number and types of hemocytes in four size groups of the clam species Sunetta scripta and Villorita cyprinoides var. cochinensis, and leukocytosis in the 38- to 40-mm-size-group clams of both species subsequent to challenge with Vibrio alginolyticus at a concentration of 1 x 10(8) cells/0.02 ml of sterile 2% saline was investigated. In S. scripta, the mean total hemocyte count in the 42- to 44-mm size group was significantly lower than that of the three other size groups but there was no significant variation in total cell counts in the four size groups of V. cyprinoides var. cochinensis. Only two types of hemocytes, granulocytes and agranulocytes, occur and the percentage of agranulocytes was roughly half of that of granulocytes. The data on the effects of sham injection and Vibrio injection suggest that there is significant leukocytosis early in both clam species as a result of sham injection; the bacterial challenge produces significant leukocytosis in V. cyprinoides var. cochinensis both early (6 and 12 hr) and later (48,96 and 120 hr), but only at 48 hr in S. scripta; and in both clam species there is significant increase in total cell counts in Vibrio-injected ones than in untampered controls at various time intervals.

Animals↗
PubMed1978

In vivo development of Echinostoma malayanum Leiper, 1911 with notes on effects of population density, chemical composition and pathogenicity and in vitro excystment of the Metacercaria (Trematoda: Echinostomatidae).

In vivo development of Echinostoma malayanum Leiper, 1911 was studied in white rats and the developmental process was arbitrarily divided into four stages: organogeny, vitellogenesis, formation of Mehlis' gland complex and cirrus sac, and oviposition. The percentage of development was 86-94. Population density affected the prepatent period of flukes and the normal prepatent period of 13-16 days was altered to 18-23 days in infection with 500-800 flukes. The majority of flukes in heavy infection were undersized and in the immature stage of development at patency. Data from chemical analysis of flukes revealed that protein, lipids, calcium and ash decreased quantitatively in flukes from higher population densities but no such change was observed as regards glycogen. Pathological changes in the rat intestine included lysis and destruction of mucosa, increased activity of goblet cells, oedematous and reticulated appearance of lamina propria and slight to moderate hyperplasia of epithelial cells. The metacercariae excysted in the medium containing trypsin plus sodium cholate an pepsin, though not essential for a high percentage of excystment, affected the rate. The reductant sodium dithionite substantially enhanced the rate and percentage of excystment. Excystation was optimal at pH 8, and 42 degrees C was more effective than 39 degrees C.

Animals↗
PubMed1976

Cerebral cryptococcosis in Malaysia.

Cryptococcal infection of the brain as encountered in a tropical country is reviewed. The meningitic form is not uncommon and there has been, in the last decade, an apparent, if not real, rise in incidence in Malaysia as in Singapore. Only exceptionally was there overt evidence of immunological deficiency. Hydrocephalus was present in about three-quarters of the patients with meningitis and shunts were employed readily. The presence of multiple small intracerebral cysts could be suspected clinically but treatment for this complication was ineffective. The antifungal agent used most frequently was 5-fluorocytosine. Resistance to this drug developed in about one patient in four. There is a need for further epidemiological studies and for a continuing search for new antifungal agents.

Adolescent↗