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Biomedical subjects

N Malla

Publications and source records attributed to N Malla.

At least 37 records · Page 2Linked to original sources
PubMed1996

Role of calcium influx & energy metabolism in histamine release by filarial antigen in Mastomys natalensis experimentally infected with Brugia malayi.

The present work was undertaken to study the biochemical pathways involved in terms of role of calcium influx and status of energy metabolism in the activation of mast cells obtained from Mastomys natalensis infected with Brugia malayi when challenged in vitro with a potentially allergenic antigen (60 kDa) of Brugia malayi. It was observed that histamine release from sensitized lung and peritoneal mast cells was associated with intracellular influx of radioactive Ca2+, thus establishing the role of calcium in histamine release. The process of activation of mast cells by 60 kDA antigen was an energy requiring process as it utilized the energy phosphates in the form of ATP and the cells followed the aerobic respiratory pathway for the generation of energy molecules.

Adenosine Triphosphate↗
PubMed1995

Evaluation of the efficacy of albendazole against the larvae of Taenia solium in experimentally infected pigs, and kinetics of the immune response.

Cysticercosis, a disease of economic and public health importance, is caused by Cysticercus cellulosae, the metacestode stage of Taenia solium. Experimental induction of cysticercosis was achieved in young pigs by feeding an optimum dose of 20,000 T. solium (Indian strain) eggs after immunosuppression, to assess the effect of albendazole and development of the immune response to cysticercus antigens before and after treatment. Histopathological studies revealed the presence of cysticerei in liver, lungs and muscles. Treatment with albendazole at 15 mg kg-1 body weight daily for 30 days starting from day 0 or 15 days post-infection resulted in 100% cure rates. Increases in antibody titre to crude soluble extract and a Sephadek G-200 purified antigenic fraction of Cysticercus cellulosae were found on days 25, 40 and 55 post-infection in untreated pigs and those in which treatment started on day 15 post-infection, whereas no increase in antibody response was observed in pigs in which treatment started on day 0.

Albendazole↗
PubMed1993

Leishmania donovani: in vitro evidence of hepatocyte damage by Kupffer cells and immigrant macrophages in a murine model.

Infection with Leishmania donovani leads to activation of liver macrophages. The role of different macrophage populations of liver in this infection is not clearly defined. Thus, the mechanism involved in hepatocyte damage was studied by coculturing hepatocytes with two populations of liver macrophages, the kupffer cells and immigrant macrophages. The results indicated maximum tissue damage at peak infection in both the macrophage populations cocultured with hepatocytes (P < 0.001). Kupffer cell-hepatocyte coculture treated with scavengers of reactive oxygen intermediates failed to inhibit the hepatocyte damage (P > 0.05). But with heparin and phenylmethylsulfonyl fluoride, a sharp decrease in the damage was noticed (P < 0.001). In contrast, immigrant macrophage-hepatocyte coculture showed a significant reduction in tissue damage when treated with both the scavengers of reactive oxygen intermediates and enzyme inhibitors (P < 0.001). Therefore the murine infection with L. donovani is speculated to involve two distinct subpopulations of liver macrophages with marked differences in morphology and functional capabilities.

Animals↗
PubMed1992

Effect of sodium stibogluconate and pentamidine on in vitro multiplication of Leishmania donovani in peritoneal macrophages from infected and drug-treated BALB/c mice.

The in vitro antileishmanial activity of sodium stibogluconate (SSG) and pentamidine in peritoneal macrophages from three different groups of animals (i.e. normal, Leishmania donovani-infected and drug-treated BALB/c mice) is reported. Peritoneal macrophages were extracted from all these animals and infected in vitro with L. donovani promastigotes. After 24 h, the infected macrophages (with amastigotes) were exposed to various concentrations of SSG (10-90 micrograms/mL) and pentamidine (0.1-5.0 micrograms/mL). The in vitro infection could be cured readily with 80 micrograms/mL of SSG and 4 micrograms/mL of pentamidine in macrophages from normal animals. But even higher dosages of these drugs added in vitro could not reduce the amastigote loads in macrophages from infected animals. In contrast, incubation in vitro of infected macrophages with very low dosages of these drugs (40 micrograms/mL of SSG and 1.0 mu/mL of pentamidine) could eliminate the parasites present within macrophages obtained from drug-treated animals. This was probably because the macrophages from drug-treated animals tackled the parasites themselves by their microbicidal mechanisms and the in vitro infection was tackled by the drug in vitro. This implies that a well-developed specific immunity in leishmaniasis helps in the antileishmanial activity of these drugs.

Animals↗
PubMed1992

Response of mast cells against filarial antigens from experimentally infected Mastomys natelensis with Brugia malayi.

The role of antigens of Brugia malayi adult worms in induction of histamine release from mast cells was studied. Both peritoneal and lung mast cells were passively sensitized using immune serum collected from Mastomys natelensis on different days after infection with B. malayi. A significant release of histamine both with crude worm and 60-kD antigens was shown. However, the role of the 43-kD antigen in histamine release was comparable to that of control. When the sera were heat inactivated, the histamine release was minimal, thus indicating the heat-labile nature of the antibodies. Furthermore, the responses of peritoneal and lung mast cells to filarial antigens were similar.

Animals↗
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

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

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↗
PubMed1991

Epidemiological study of parasitic infestations in lower socio-economic group in Chandigarh (north India).

When stool samples from 970 subjects belonging to lower socio-economic groups were examined for parasites, a total of 121 subjects (12.5%) i.e., 57 (12.1%) males and 64 (12.9%) females showed positive results. The overall prevalence of parasitic infestation did not correlate with sex, caste or religion and living conditions. However, the prevalence was higher in hospital employees residing in well sanitated area. Giardia lamblia (69.5%), Entamoeba, histolytica (15.7%), Hymenolepis nana (12.4%), Ancylostoma duodenale (10.7%), Ascaris lumbricoides (8.3%) and Taenia (0.8%) were the parasites seen. Mixed infections were seen in 9 subjects. Twenty families of the 196 studied had more than one family member positive for parasites. Asymptomatic positivity was high amongst all groups of subjects, and with all parasites.

Adolescent↗
PubMed1990

Effect of sodium stibogluconate on the status of interleukin-I production in normal & Leishmania donovani infected BALB/c mice.

Sodium stibogluconate, did not bring about significant increase in the production of IL-1, when both specific leishmanial antigen, or non specific Staphylococcus epidermidis was used as stimulus in normal uninfected animals. However, Staph. epidermidis was found to be a better stimulus as it brought about a significant increase (P less than 0.001) in IL-1 production when compared with leishmania antigen. In BALB/c mice infected with L. donovani there was a significant reduction (P less than 0.001) in IL-1 levels on various post infection days irrespective whether Staph. epidermidis or leishmanial antigen was used as stimulus when compared with controls. IL-1 levels were significantly increased (P less than 0.05) when L. donovani infected animals were treated with SSG, after 14 days post infection, irrespective of the stimuli used.

Animals↗
PubMed1989

Lymphokine mediated microbicidal activity of peritoneal macrophages from Leishmania donovani infected and drug treated BALB/c mice.

The resident peritoneal macrophages from untreated mice develop potent microbicidal activity against amastigotes of Leishmania major and Leishmania donovani after in vitro exposure to lymphokines (LK) from mitogen stimulated spleen cells. However, to the best of our knowledge, the response of L. donovani infected peritoneal macrophages from already infected/treated animals to LK has not been investigated. Therefore in the present study, the effect of LK on infected macrophages from BALB/c mice following specific infection and subsequent treatment with sodium stibogluconate has been investigated. As the infection progressed, a decrease in percent microbicidal activity was noticed. An attempt was also made to treat the animals on different post infection days and reinfect them in vitro. Infection could not be produced in vitro in late treatment groups when the treatment was given on 14 days and 21 days post infection. Whereas, macrophages obtained from animals treated on 7 days post infection (early treatment) could be infected in vitro. However, only 50% of the cells got infection. This infection was eliminated when the cells were exposed to LK for 72 hours.

Animals↗
PubMed1989

Dot enzyme linked immunosorbent assay for immunodiagnosis of amoebiasis.

Dot-enzyme linked immunosorbent assay (Dot-ELISA) used for the serodiagnosis of both intestinal and extraintestinal amoebiasis, showed positivity in 94 per cent patients of amoebic liver abscess and 87.5 per cent of intestinal amoebiasis. Only one of the 18 normal controls was positive by Dot-ELISA test. This test showed good correlation with indirect haemagglutination test. As it is simple and easy to perform, the test appears to have great potential for the specific diagnosis of amoebiasis in peripheral hospitals and also at the field level where sophisticated immunodiagnostic facilities are not available.

Dysentery, Amebic↗