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Biomedical subjects

M K Basu

Publications and source records attributed to M K Basu.

At least 19 recordsLinked to original sources

Effect of Cu(2+)-ascorbic acid on lipid peroxidation, Mg(2+)-ATPase activity and spectrin of RBC membrane and reversal by erythropoietin.

The effect of erythropoietin (Ep), a glycoprotein hormone, has been studied on lipid peroxidation induced by Cu2+ and ascorbate in vitro, Mg2+ ATPase activity and spectrin of RBC membrane. Our present investigation reveals that Cu2+ and ascorbic acid increases lipid peroxidation of RBC membrane significantly. It has further been observed that under the same experimental condition spectrin, a major cytoskeleton membrane protein, and Mg(2+)-ATPase activity of RBC membrane decrease significantly. However, exogenous administration of Ep completely restores lipid peroxidation and Mg(2+)-ATPase activity and partially recovers spectrin of RBC membrane.

Animals

Oral papillary plasmacytosis resembling candidosis without demonstrable fungus in lesional tissue.

Two cases with exuberant papillary and nodular hyperplasia of the hard and soft palates are described. Both were elderly edentulous men with bilateral angular stomatitis. The papillary hyperplasia extended as far as the epiglottis and was associated with swelling and fissuring of the upper lip in patient 1. In patient 2, the palatal change extended to the maxillary gingiva and was associated with smooth plaques and fissuring of the dorsal tongue. Histology of both cases showed a dense polyclonal plasma-cell infiltrate with overlying epithelial hyperplasia, parakeratinization and neutrophil micro-abscesses suggesting Candida infection but fungal elements could not be demonstrated. Patient 1 also showed defective cellular immunity to Candida antigen which was reversed by treatment with ketoconazole and levamisole, antedating clinical improvement.

Aged

Gingival Kaposi's Sarcoma: the first indication of HIV infection.

This article presents a case of gingival Kaposi's sarcoma that initially mimicked an acute periodontal infection, but was the first clinical sign of HIV infection in a 38-year-old male homosexual patient. The clinical features and treatment of oral Kaposi's sarcoma are discussed and the variable histopathology of the lesion is demonstrated.

Adult

Fluidity-dependent Mg2(+)-ATPase activity in membranes from Leishmania donovani promastigotes.

The state of the lipid phase of the membrane plays a key role in the exposure of various receptors, antigens and enzymes on the membrane surface. The fluidity of membranes of Leishmania donovani promastigotes was monitored by two independent methods, i.e. influx of sterol from liposomes and removal of phospholipids by treatment with phospholipase C. The altered sterol/phospholipid ratio, in both cases, provided evidence that the activity of the functionally important membrane-bound enzyme Mg2(+)-ATPase is modulated by the state of the lipid phase of the membrane.

Animals

Multiple idiopathic external resorption of teeth.

Three cases of multiple idiopathic external resorption are presented. The condition is characterised by the absence of any widespread inflammatory response both in the gingival tissues and within the dental pulp. The only curative treatment is exodontia.

Adult

Targeting of plant glycoside-bearing liposomes to specific cellular and subcellular sites.

The possibility of using liposomes as an effective drug delivery system has been studied by incorporation of two plant glycosides of varying terminal sugar residues onto the surface of liposomes and examination of their distribution in different tissues. The two glycosides, corchorusin D and asiaticoside having glucose and rhamnose respectively at the terminal ends wee selected for the purpose. The hepatic uptake of liposomes made from egg lecithin, cholesterol and dicetyl phosphate and either of the two glycosides was compared. The hepatic uptake of asiaticoside bearing liposomes was reduced, whereas that of corchorusin D bearing liposomes was enhanced and was specific for glucose. Liver perfusion followed by cell separation showed that the uptake is mostly into the non-parenchymal cells of liver. The distribution of corchorusin D bearing liposomes was maximal in the lysosomal fraction of the non-parenchymal cells. Ways of using corchorusin D bearing liposomes as delivery systems for drugs or enzymes to lysosomes have been sought.

Agglutination Tests

Synovial fluid glycosaminoglycan (acid mucopolysaccharide) analysis in assessment of temporomandibular joint dysfunction. A pilot study.

Temporomandibular joint (TMJ) synovial fluid was aspirated from normal control subjects and patients undergoing surgery for TMJ dysfunction. The glycosaminoglycan (GAG) composition of this fluid was analysed and compared with the clinical diagnosis and histological appearance of the condylar tissues. Changes in GAG composition were observed where a histologically hyperplastic response was seen in joint tissues, but these findings did not necessarily correlate with the initial clinical diagnosis. It is suggested that the fluid composition reflects the current metabolic activities of the tissues and may provide a useful marker of such processes.

Adult

Elastic cartilage in the incisive canal region: report of a case.

A man complained persistently of 'gritty bits' coming into his mount from behind the upper front teeth over a period of 10 years. Elastic cartilage was found within fibrous connective tissue of the incisive papilla region and it is suggested that transepidermal elimination of elastotic material, as happens in perforating dermatoses, was responsible for this patients complaint.

Cartilage

Mast cells in human odontogenic cysts.

Mast cells have been shown to be present in substantial numbers in both nonkeratinizing and keratinizing odontogenic cysts and could be seen in the connective tissue capsule and the epithelial lining. Within the cyst capsule, mast cells were more prevalent just beneath the epithelium than in deeper areas. This distribution pattern for mast cells is in accord with the histochemical picture for heparin staining in odontogenic cysts. In the non-keratinizing cysts, there appeared to be some trend towards mast cells being associated with increasing inflammation but not in the odontogenic keratocyst. No evidence could be found for distinct mast cell subpopulations in odontogenic cysts. The presence of mast cells in odontogenic cyst could contribute to their pathogenesis in several ways.

Cell Count

Leishmania donovani: superoxide dismutase level in infected macrophages.

Superoxide dismutase (SOD), a metal containing enzyme is present in parasite Leishmania donovani as well as in host macrophages both resident and activated in a detectable amount, although the level is much higher in the latter case. It is observed that at any particular protein concentration, the SOD activity is highest in the case of parasite infected macrophages and lowest in the case of normal resident macrophages; the SOD activity of thioglycolate activated macrophages lies in between the two. It is also noticed that formalin-killed Leishmania donovani neither attach to macrophages nor do they increase the SOD activity of the host. Thus, the processes, e.g. attachment of the parasite to the host membrane, subsequent membrane perturbation and thus activation of membrane bound enzyme NADPH oxidase leading to respiratory burst, may be responsible for an enormous increase in the SOD level in macrophages during infection. Moreover, the chemical nature of the SOD found in infected macrophages has been investigated by using an inhibitor, e.g. NaCN, which specifically inhibits Cu-Zn SOD but not Fe-SOD. A considerable inhibition of SOD activity by NaCN in infected macrophages confirms the chemical nature of the increased SOD to be of Cu-Zn type, usually found in host. Presumably, Cu-Zn SOD or host SOD plays a protective role at the time of parasite infection although the role of parasitic SOD or some other mechanisms for the survival of the parasite within the toxic phagolysosome environment of the macrophage cannot be ruled out.

Animals

Leishmania donovani: role of microviscosity of macrophage membrane in the process of parasite attachment and internalization.

Host macrophage infection by the parasite Leishmania donovani is heterogeneous, but it is not clear which factors are responsible for parasite recognition within the macrophages. One possible factor may be the alteration of the microviscosity of the macrophage membrane. This in turn may affect receptor expression and hence parasite infection. In this paper we describe alteration of the lipid composition and hence the microviscosity of the macrophage membrane in a controlled manner using liposome fusion technique. At a higher macrophage membrane microviscosity a larger number of parasites have been found to adhere to the macrophage surface. However, the proportion of parasites finally internalized when compared to parasites adhering to macrophages is inversely correlated with the artificially altered macrophage membrane microviscosity. The process of endocytosis has been examined in both native and lipid modified macrophages in the presence of several sugar antagonists. The results indicate (i) glucose and mannose are specifically involved in the binding process, and (ii) the microviscosity has a key role in controlling the macrophage parasite interaction. The results obtained so far support a model of endocytosis where expression of the receptor is a critical initial process dependent on the microviscosity of the membrane.

Animals

Phospholipids from the hepatopancreas of Indian horseshoe crab Carcinoscropius rotundicauda.

Total phospholipids were extracted from the heart, hepatopancreas, and hemolymph of the Indian horseshoe crab Carcinoscorpius rotundicauda by the conventional method. Characteristic group reaction and 2-dimensional thin-layer chromatography on silica gel were used for identification of different phospholipids. The phospholipid profile obtained from hemolymph and 2 major organs are comparable and show phosphatidyl choline (PC) and phosphatidyl ethanolamine to be the major phospholipids. A phospholipid has been consistently detected migrating immediately below the PC in the thin-layer chromatogram of lipids extracted from the hepatopancreas. When mixed methyl esters of this slower moving PC are resolved on a silica gel plate ran in hexane ether:acetic acid 80:20:1, with appropriate controls, an additional spot is seen just below the normal methyl ester, indicating a difference between the fatty acid compositions of 2 PC (e.g., regular and slower). The slower mixed methyl esters were found to comprise mainly the 4 saturated fatty acids: lauric, myristic, palmitic, and stearic. The slow moving PC seems to consist mainly of molecular species with the above-mentioned saturated fatty acids at both Sn 1 and Sn 2 positions.

Animals

The post-operative maxillary cyst. Experience with 23 cases.

23 cases, diagnosed as post-operative maxillary cyst, from outside Japan are described. Clinical, radiographic and histopathological features are not dissimilar to those cases reported from Japan, and various parameters have been found to be helpful in diagnosis. This lesion is more common outside Japan than previously suggested, and this is probably largely due to faulty diagnosis.

Adult