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Biomedical subjects

K Mehta

Publications and source records attributed to K Mehta.

At least 127 records · Page 7Linked to original sources
PubMed1982

IgE-dependent cellular adhesion and cytotoxicity to Litomosoides carinii microfilariae--nature of effector cells.

Albino rats immunized with sonicated microfilarial antigen incorporated in Freund's complete adjuvant, produce antibodies that promote cell-mediated adhesion and killing of Litomosoides carinii microfilariae in vitro. Using highly purified cell populations, it has been shown that macrophages and neutrophils are most active in this phenomenon. Eosinophils, while adhering readily to parasites in the presence of the antibody, did not affect the viability of the parasites when observed after 24 hr incubation.

Animals↗
PubMed1982

Uptake of liposomes and liposome-encapsulated muramyl dipeptide by human peripheral blood monocytes.

The interaction of multilamellar liposomes with human peripheral blood monocytes, cultured in vitro, has been examined. Phagocytic engulfment is the principal mechanism by which the liposomes are taken up by these cells. Studies with radiolabeled liposomes revealed that they are taken up by monocytes as intact structures. The uptake is temperature sensitive and is affected by inhibitors of glycolysis and of microfilament activity. Monocytes take up negatively charged vesicles more rapidly than positively charged (3-fold) vesicles or neutral vesicles (5-fold). Increase in negative charge of liposomes enhances their uptake by the cells, but increased saturation of the phospholipids results in decreased uptake. Liposomes provide an effective means of enhancing the uptake of MDP derivatives (3H nor MDP) by monocytes, with a 20-fold greater uptake of liposome encapsulated drug than of the free compound. Monocytes do not degrade the 3H-nor MDP that they have internalized and radiolabel is only slowly released from the cells. These observations suggest a pharmacokinetic basis for the use of lipid vesicles as a system for the delivery of immunomodulating drugs to monocytes.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1981

Immunogenicity of homogenates of the developmental stages of Litomosoides carinii in albino rats.

Homogenates of different developmental stages of the filarial parasites, L. carinii, emulsified in Freund's complete adjuvant have been examined for their efficacy in conferring immunity to the infection in the albino rats. The results revealed that sonicated preparations of microfilariae and infective larvae induce high resistance to the infection in the animals. In contrast, soluble antigens of adults and sonicated homogenates of adult males were ineffective to induce such resistance. Some resistance seen when sonicated adult worms of both sexes were used as immunogens appears to be due to the microfilarial antigen present in the extracts.

Animals↗
PubMed1981

Antibody-dependent cell-mediated effects in bancroftian filariasis.

The nature of immunoglobulin and effector cells involved in the antibody-dependent cell-mediated adhesion and cytotoxicity to Wuchereria bancrofti larvae has been investigated. Human neutrophils and eosinophils purified from peripheral blood by metrizamide gradients readily adhered to the parasites in presence of IgG fraction of sera from majority of elephantiasis cases with amicrofilaraemia and many of the endemic normals. The cells from normal, microfilariae and elephantiasis cases were equally effective inthe adhesion reaction. While the adhered neutrophils killed the larvae, eosinophils were ineffective in this respect. DEC treatment of elephantiasis cases results in a significant reduction in the ability of their sera to promote cellular adhesion.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1981

Oculoplethysmography and pulsed Doppler ultrasonic imaging in diagnosis of carotid arterial disease.

The individual and combined diagnostic accuracy rates for fluid-filled oculoplethysmography and pulsed Doppler ultrasonic imaging in the detection of extracranial carotid artery insufficiency were calculated. Results of the two techniques were compared with those of contrast arteriograms which were available for 109 patients, 210 arteries, for computations of sensitivity and specificity. Sensitivities for oculoplethysmography and ultrasonic imaging were 84 and 87 per cent, while specificities were 87 and 81 per cent, respectively. These values were not significantly, p greater than 0.05, different. Results of oculoplethysmography and ultrasonic imaging agreed in four-fifths of the arteries, producing a sensitivity of 98 per cent and a specificity of 97 per cent. In the remaining arteries, the results of the two tests did not agree, resulting in a sensitivity of 71 per cent and a specificity of 79 per cent. Fluid-filled oculoplethysmography and pulsed Doppler ultrasonic imaging are diagnostic tests of comparable accuracy which, when used together, provide accurate hemodynamic and anatomic information in the diagnosis of extracranial carotid arterial disease.

Adult↗
PubMed1981

Enhanced adhesion of rat neutrophils to Litomosoides carinii microfilariae in the presence of culture supernatants from mitogen-stimulated lymph node cells.

Microfilariae of the rat filarial parasite Litomosoides carinii are killed by normal rat neutrophils which adhere to them in the presence of antibody and complement. Adherence and killing were increased in the presence of the fluid from 48-hr cultures of Con A- or PHA-stimulated normal rat lymph node cells. Both normal and augmented binding were inhibited by cytochalasin B. The factor(s) responsible for increased binding was non-dialysable, susceptible to heat (56 degrees C, 30 min) and freezing and thawing. Its production was inhibited by cycloheximide. Pretreatment of neutrophils with stimulated culture supernatant for 3 hr, followed by washing, also augmented adherence. Similar pretreatment also enhanced phagocytosis of opsonized sheep erythrocytes and latex particles but did not increase candidacidal activity. These experiments suggest that cell-mediated immune reactions leading to lymphokine production may potentiate anti-filarial antibody-dependent cellular cytotoxicity and general phagocytosis by neutrophils.

Animals↗
PubMed1980

Below-knee bypass for limb salvage. Comparison of autogenous saphenous vein, polytetrafluoroethylene, and composite dacron-autogenous vein grafts.

Autogenous saphenous vein was used preferentially for 92 below-knee bypass procedures (44 femoral-distal popliteal and 48 femoral-distal tibial or peroneal) performed for limb salvage in 87 adult male patients during a 30-month period of study. When a saphenous vein was unavailable or of unsuitable length or diameter, we randomly used expanded polytetrafluoroethylene (PTFE) and composite Dacron-autogenous vein (DV) grafts. With good run-off, all grafts have remained patent. However, with poor run-off, cumulative patency by the life table method decreased to 54% for autogenous saphenous vein and 45% for PTFE, which was not significantly different. All composite DV grafts used with poor run-off became occluded within the first ten months of the study. We continue to recommend use of autogenous saphenous vein for revascularization of the ischemic lower extremity. When a suitable saphenous vein is unavailable, PTFE is a satisfactory alternative graft that is superior to composite DV grafts.

Aged↗
PubMed1980

IgE-dependent adherence and cytotoxicity of rat spleen and peritoneal cells to Litomosoides carinii microfilariae.

Serum taken after the termination of microfilaraemia from rats infected with the filarial parasite Litomosoides carinii brought about adherence and cytotoxicity of normal rat spleen and peritoneal cells to microfilariae. The activity could be absorbed to, and eluted from, anti-rat IgE, but not anti-rat IgG, immunosorbent columns. Immune serum heated to 56 degrees C for 3 hr did not cause cellular adherence or cytotoxicity; the addition of fresh normal rat serum failed to restore activity. Fresh rat serum did, however, restore activity to immune serum which was inactive after being heated to 56 degrees C for 30 min. EDTA, EGTA and diethylcarbamazine inhibited adherence. It is concluded that IgE antibodies are responsible for cellular adherence and cytotoxicity and that complement may play a part, as yet undefined, in these reactions.

Animals↗
PubMed1978

Effect of borax on testis of Indian desert gerbil, Meriones hurriane Jerdon.

Borax was injected at a dose level of 250 mg/kg b. wt for 16 days (total dose 4 g/kg b. wt) s.c. to active adult male gerbils. Borax caused several degenerative changes in the testes, of which giant cell formation, pyknosis and exfoliation are prominent. The increased activity of phosphatases was also noticed.

Animals↗
PubMed1978

Immune reactions in human filariasis.

Sera from cases of elephantiasis due to Wuchereria bancrofti infection promoted an intense adhesion of peripheral blood leukocytes to W. bancrofti microfilariae in vitro. A similar adhesion was also seen using sera from some normal persons living for several years in areas where filariasis is endemic. No such adhesion was evident with sera from microfilaria carriers or from normal subjects from nonendemic areas. The adhesion was complement independent and was associated with the immunoglobulin G fraction of serum. 51Cr release studies suggested the occurrence of cell-mediated cytotoxicity to W. bancrofti microfilariae in the presence of elephantiasis serum. Microfilariae of Litomosoides carinii could be isolated free of blood cells, from the blood of infected rats. In the presence of serum, or its immunoglobulin G fraction, from patients with elephantiasis, L. carinii microfilariae adhered to human peripheral blood leukocytes or rat spleen cells.

Animals↗