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Biomedical subjects

R C Mahajan

Publications and source records attributed to R C Mahajan.

At least 73 records · Page 4Linked to original sources
PubMed1992

Evaluation of enzyme linked immunosorbent--assay for the detection of anticysticercus antibodies in cerebrospinal fluid from patients with neurocysticercosis.

Enzyme linked Immunosorbent Assay (ELISA) was done for the detection of antibodies to Cysticercus cellulosae in 135 cerebrospinal fluid (CSF) and 152 serum samples from patients suspected clinically of neurocysticercosis (NC), neurological disorders other than NC and controls by the use of crude cyst extract antigen. This assay was compared with the standard technique of indirect haemagglutination test (IHA). The results of the two techniques were matched with retrospective analysis of proven diagnosis of these patients. ELISA and IHA was found to be positive respectively in 88 and 84 percent of CSF and 92 and 87.2 percent of serum samples from proven NC patients. The IHA technique was found to be absolutely specific for the detection of antibodies in CSF samples while cross reactions were observed with ELISA technique in CSF from 5 patients, one each suffering from disappearing CT scan lesion, tubercular meningitis (culture negative), chronic meningitis, benign intracranial hypertension and non compressive myelopathy. However possibility of neurocysticercosis cannot be absolutely ruled out in such patients. Both the techniques were found to be highly non specific for the detection of antibodies in serum samples. The study suggests that either of the two techniques may be used for the detection of antibodies in CSF samples from clinically suspected NC patients with high degree of sensitivity and specificity.

Antibodies, Helminth↗
PubMed1991

Anti-trichomonad IgA antibodies in trichomoniasis before and after treatment.

Anti-trichomonad IgA antibodies were estimated by enzyme-linked immunosorbent assay (ELISA) in serum and vaginal secretions of 25 symptomatic and 25 asymptomatic Trichomonas vaginalis positive patients before and after treatment and in 25 age-matched controls. Significantly higher levels of antitrichomonad IgA antibodies were found in T. vaginalis positive patients when compared to control subjects, especially in vaginal secretions. In addition, a significant decrease in these antibodies was observed after treatment, which was more pronounced in vaginal secretions. It seems that anti-trichomonad IgA antibodies in serum and more so in vaginal secretions are directly related to and specific to the presence of T. vaginalis in the urogenital tract.

Adult↗
PubMed1991

In vitro effect of larval stages of Ascaris lumbricoides on human blood clotting.

The effects of larval stages of Ascaris lumbricoides on human blood clotting was studied in vitro. Extracts and excretory/secretory products of third-stage larvae (L3) and late third-stage larvae (LL3) cultured from ova obtained from infected patients were analysed for anti-coagulant activity. Prothrombin time (PT) was prolonged by the addition of either whole extract of L3/LL3 or ES products of L3/LL3 as compared to controls. Partial thromboplastin time with kaolin (PTTK) was also prolonged on the addition of either extracts of ES products of L3/LL3. The prolongation of PTTK was significantly higher with extracts/ES products of L3 when compared to the extracts/ES products of LL3 (p less than 0.005). Thrombin time (TT) was prolonged by extracts of L3/LL3 and their ES products.

Animals↗
PubMed1991

Effect of nifedipine on Leishmania donovani infection in-vivo and in-vitro: chemiluminescence responses of peritoneal macrophages and neutrophils.

After peritoneal macrophages had been exposed to different concentrations of nifedipine (10-120 ng mL-1) there was a significant increase (P less than 0.001) in the percentage of Leishmania donovani infected macrophages compared with controls. Parasite load was also significantly increased (P less than 0.001) in nifedipine-treated, L. donovani infected, BALB/c mice, compared with untreated, infected mice, post-inoculation. Peak chemiluminescence responses were significantly depressed (P less than 0.001) in nifedipine-treated infected mice compared with untreated mice post-inoculation. It is suggested that availability of intracellular calcium is a factor in the defense mechanism of inflammatory cells in L. donovani infections.

Animals↗
PubMed1991

Evaluation of RNA rich fraction of Litmosoides carinii in induction of protection in infected rats.

The RNA rich fraction of adult L. carinii worms was evaluated in evoking a protective response in infected rats. The RNA immunization was seen to be effective in limiting the microfilaraemia in peripheral blood as well as the adult worm burden. The antibodies to both RNA antigen and adult worm antigen were high in this group of animals at the peak of infection. The RNA immunization was seen to evoke hyperresponsiveness in lymphocytes to mitogens like adult worm antigen, PHA and Con A.

Animals↗
PubMed1991

Malaria screening to prevent transmission by transfusion: an evaluation of techniques.

Transfusion-associated malaria is often severe or even fatal, because diagnosis is frequently delayed and it complicates an already serious underlying disorder. Detection of infected donors is difficult in endemic areas due to the lack of a suitable donor screening test. Blood smear staining techniques show poor results due to the low parasite concentration in many infected persons, and the antibody detection test is not helpful due to the universal presence of antibody in healthy donors in these areas. For comparative evaluation of various screening tests, 9131 blood smears from voluntary donors and a group of patients were screened by Giemsa staining. Ten (0.10%) subjects showed parasitaemia, whereas Acridine Orange fluorescence staining showed 13 (0.14%) parasitaemia in almost the same number of smears screened on the same samples. Significantly high levels of malarial antibody were detected in 12.6% and 19.86% of subjects by indirect fluorescent antibody and enzyme-linked immunoassay tests, respectively. Malarial antigen detection by monoclonal antibody showed positive results in 9.48% of subjects, demonstrating excellent results and showing direct evidence of infection. We recommend that this should be adopted as a screening technique by transfusion services in endemic areas in order to prevent post transfusion malaria.

Acridine Orange↗
PubMed1991

Phagocytic capacity of Kupffer cells during hepatic amoebiasis in guinea pigs.

Very few studies have been carried out on the role of liver macrophages (Kupffer cells) during the course of hepatic amoebiasis. The kinetics of phagocytic activity of Kupffer cells and blood monocytes was studied in guinea pigs intra-mesenterically infested with Entamoeba histolytica. The phagocytic capacity of blood monocytes of normal animals was comparatively lower than Kupffer cells for both latex and haemolysin coated sheep red blood cells. Significant decline in phagocytic response of Kupffer cells and blood monocytes of infected animals was observed right from 2nd post infection day and it kept on decreasing with the progress of infection. Depression in phagocytic response of Kupffer cells and blood monocytes was more marked in those animals who had higher grades of pathological lesions. Hence, an inverse correlation was obtained between the phagocytic capacity and severity of amoebic lesions (P less than 0.01). The significance of depression in phagocytic response of Kupffer cells and blood monocytes may be responsible for the development of hepatic lesions.

Animals↗
PubMed1991

Plasmodial antigen detection by monoclonal antibody as a screening procedure for blood donors in transfusion medicine.

Very little information is available as regards the methods to be advocated to prevent transfusion malaria, especially in endemic countries. Most of the malaria non-endemic countries follow the rule of donor deferral for 3 years after malaria infection. This criterion cannot be followed in endemic areas since the majority of the population is continuously exposed to this infection. Therefore, there was a long felt need for a suitable screening procedure for blood donors to make the transfusion therapy safe. A total of 6,435 blood donors and 3,621 patients who received blood from these donors were studied by blood smears examination and malarial antigen detection by specific monoclonal antibody. Smear examination by Giemsa and acridine orange staining methods showed poor results (0.06% and 0.1% positivity respectively), probably due to low concentration of parasites. However, antigen detection by monoclonal antibody confirmed specific diagnosis in majority of these subjects. Blood smear examination failed to reveal malaria infection in 92.3% of antigen positive blood donors. It is, therefore, recommended that antigen detection by monoclonal antibody should be adopted as a routine screening procedure by the blood transfusion services in malaria endemic countries like India.

Animals↗
PubMed1991

A comparison of wet mount, culture and enzyme linked immunosorbent assay for the diagnosis of trichomoniasis in women.

One thousand women in the child bearing age group, attending the Obstetrics and Gynaecology Outpatient Department, were investigated for the presence of Trichomonas vaginalis in their vaginal discharges. T. vaginalis was isolated in 68 patients (6.8%) by wet mount and/or culture. 55 cases (80.9%) were detected by wet mount examination and 67 (98.5%) by culture in TPS-I medium. Significant levels of antitrichomonal IgA antibody in the vaginal secretions by micro-ELISA technique were detected in 38 out of 50 subjects (76%) harbouring T. vaginalis in whom this assay was carried out. Culture was found to be the single most sensitive method for diagnosing trichomoniasis in women.

Adolescent↗
PubMed1991

Donor screening for malaria by antibody and antigen detection in endemic area.

Transfusion-associated malaria is one of the dreaded threats to the safety of transfusion services in this malaria endemic world. The main drawback in preventing this menace is that routine blood donor screening techniques are not very satisfactory. In this study, blood donors were screened for antimalarial antibody by micro ELISA and Indirect Fluorescence Antibody (IFA) test and malarial antigen by monoclonal antibody (MAB) technique. A total of 19.37% and 12.39% blood donors showed significantly high antibody by ELISA and IFA test respectively, and 0.35% donors showed the presence of antigen by the MAB technique. Solitary dependence on malarial antibody detection as a screening test might have led to rejection of 19.02% blood donors without any apparent infection. So antigen detection in blood donors with the help of the MAB technique seems to be more sensitive and a practically feasible screening test to prevent transfusion malaria.

Animals↗
PubMed1991

Humoral immune response of normal rhesus monkeys during primaquine administration.

Humoral immune response of normal rhesus monkeys was studied after giving a standard dose of primaquine. The drug did not effect the level of complement (C3) and its haemolytic activity. Levels of Immunoglobulin i.e. IgG, IgM & IgA and number of immunoglobulin secreting cells also remained unaffected. Results of this study suggested that primaquine did not suppress the immune status of the host and could be given safely to the malaria patients.

Animals↗
PubMed1991

Oxidative metabolic response of peripheral blood monocytes of monkeys during primary and chronic Plasmodium knowlesi infection.

The oxygen free radical generation (as determined by cytochrome c reduction) and respiratory burst enzyme activities were measured in the peripheral blood monocytes before infecting normal animals, during primary Plasmodium knowlesi infection, after treatment of primary infection with chloroquine, after administration of various subcurative doses following reinfection and after establishment of chronicity. For all the parameters of the oxidative response, no significant difference was observed during primary infection and after curing of primary infection. However, the response was significantly increased in the reinfected monkeys given subcurative therapy; this was followed by a sharp decline after the 4th subcurative dose, after which the response continued to be low until the attainment of chronicity. The results of the present study exclude the possibility of the increase in oxidative metabolism being the effect of the drug (i.e. chloroquine), since no significant difference was observed during primary infection and after its cure. The sustained low grade parasitaemia in the chronic stage, in spite of the sharp decrease in the oxidative response, suggests that some nonoxidant parasitic killing mechanism might be playing a role in the regulation of parasitaemia.

Animals↗
PubMed1991

Human milk containing specific secretory IgA inhibits binding of Giardia lamblia to nylon and glass surfaces.

The effects of human milk, containing specific secretory IgA, on the adherence of Giardia lamblia trophozoites in the presence and in the absence of intestinal mucus in vitro were studied. It was found that the trophozoites treated with breast milk, containing specific secretory IgA to G. lamblia, showed a significant decrease (p less than 0.01) in adherence to nylon fibre columns and glass surfaces than did trophozoites treated with milk containing no SIgA antibodies. The adherence to glass surfaces was significantly more (p less than 0.01) in the presence of intestinal mucus than when the mucus was absent. Milk that did not contain specific secretory SIgA to G. lamblia did not decrease the adherence to glass surfaces either in the presence or in the absence of mucus. The fluorescence study revealed the binding of specific secretory IgA on the trophozoite surface. The results suggest that binding of SIgA antibodies in milk to G. lamblia trophozoites inhibits parasite adherence, thus protecting against this infection in breast-fed babies.

Animals↗
PubMed1991

Role of calcium and calmodulin in Giardia lamblia-induced diarrhoea in mice.

The unidirectional fluxes of Na+, Cl- and Ca2+ across the small intestinal epithelium of normal and Giardia lamblia-infected mice were studied in vitro in short-circuited tissue. Net secretion of Na+ and Cl- was observed in infected animals, whereas in non-infected (control) animals there was net absorption of Na+ ions and marginal secretion of Cl- ions. In infected animals, net absorption of Ca2+ was observed as compared to little secretion observed in control animals. Although the presence of Ca(2+)-ionophore in the medium resulted in a net secretion of Na+ and Cl- in controls, it could not cause any change in the fluxes of these ions in infected animals. Verapamil, a calcium channel blocker, reversed the effects of infection and Ca(2+)-ionophore. Further W7 (n-(6-aminohexyl)-5 chloro-1-naphthalene sulphonamide), a calmodulin antagonist, also reversed the effects of infection. The addition of the neurotoxin, tetrodotoxin caused net absorption of Na+, Cl- and net secretion of Ca2+ in the control group, but it could not produce any effect on the fluxes of these ions in the infected group. These findings demonstrate that, in G. lamblia infection, the secretion of Na+ and Cl- is associated with an increase in absorption of Ca2+ and an increase in calmodulin activity in intestinal microvillar core. These findings further suggest that the enteric nervous system plays a marginal role in Giardia infection.

Animals↗
PubMed1991

Generation of reactive oxygen species by blood monocytes in human Plasmodium falciparum and P. vivax infections.

Generation of reactive oxygen radicals by peripheral blood monocytes was measured by luminol-dependent chemiluminescence in 23 P. vivax- and 7 P. falciparum-infected patients. The chemiluminescence index (CLI) was not found to be significantly higher in P. vivax-infected cases than in healthy controls. But in patients with P. falciparum infection, the CLI was significantly higher compared to controls as well as to P. vivax-infected patients. In two severe and complicated P. falciparum-infected cases, CLI was found to be higher than in mild cases. As immunosuppression is more marked in falciparum malaria than in vivax cases, the role of oxygen radical generation in immunopathology and causation of immunosuppression in falciparum malaria needs further investigation.

Animals↗
PubMed1991

Correlation of zymodeme patterns, virulence & drug sensitivity of Trichomonas vaginalis isolates from women.

Characterization of T. vaginalis strains isolated from symptomatic and asymptomatic subjects was done by isoenzyme analysis. The pathogenicity of these isolates was checked in mouse model and in vivo drug susceptibility was determined. The isolates from symptomatic and asymptomatic individuals could not be grouped on the basis of isoenzyme analysis alone. All the strains except one, were pathogenic for mice, and metronidazole (50 mg/kg body weight) was effective in protecting the mice from T. vaginalis infection.

Adult↗