ABSTRACT
During L. donovani infection in golden hamsters, tremendous hepatic damage was observed as apparent from increased activities of glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, succinate dehydrogenase, glucose-6-phosphatase and acid ribonuclease. The levels of cytochrome P-450 and related monooxygenases, viz. aniline hydroxylase and aminopyrine-N-demethylase registered significant decrease in infected animals. Sodium stibogluconate, a standard antileishmanial drug, though caused the removal of parasites from infected tissues, but did not help in the recovery of deranged hepatic markers. The results explain the higher mortality of stibanate treated infected animals as compared to untreated animals infected with L. donovani.
Subject(s)
Animals , Antimony Sodium Gluconate/pharmacology , Antiprotozoal Agents/pharmacology , Cricetinae , Leishmania donovani , Leishmaniasis, Visceral/drug therapy , Liver/drug effects , Male , Mesocricetus , Mixed Function Oxygenases/metabolismABSTRACT
On exposing promastigotes of L. donovani (Dd-8) to 34 degrees C for 30 hr, the flagella were shed, and size was decreased with 10% viability loss. The in vitro and in vivo infectivity of two forms was more or less similar. The 45Ca2+ uptake by the transformed cells was increased as compared to normal cells. Activity of 5'-nucleotidase was increased while activity of Mg(2+)-ATPase remained same. Parasite antioxidant enzymes were also significantly altered by heat shock. There was significant increase in superoxide dismutase, glutathione reductase and glutathione peroxidase. It was accompanied by decrease in ratio of reduced glutathione to oxidized glutathione.
Subject(s)
Animals , Glutathione/metabolism , Glutathione Peroxidase/metabolism , Glutathione Reductase/metabolism , Hot Temperature , Leishmania donovani/enzymology , Oxidation-Reduction , Superoxide Dismutase/metabolismABSTRACT
During Leishmania donovani infection of golden hamsters, changes in the glutathione levels of lymphoid tissues were observed. While in liver and thymus there was significant decrease in the levels of reduced and oxidised glutathione, that in spleen, bone marrow cells, peritoneal exudate cells and lymph nodes increased, indicating a role for host glutathione in establishing the infection.
Subject(s)
Animals , Cricetinae , Glutathione/metabolism , Leishmania donovani , Leishmaniasis, Visceral/metabolism , Lymphoid Tissue/metabolism , Male , MesocricetusABSTRACT
The impact of interamidine distance on antileishmanial activity of new aryldiamidines have been evaluated against amastigotes of L. donovani in hamster. Of the 20 compounds tested, only four (2,8-diamidino-9,10-dihydrodibenzoxepin; 2,7-diamidinoxanthone; 2,7-diamidinothioxanthone and 2,7-diamidinoxanthene) showed significant inhibition (more than 80%) of multiplication of amastigotes in spleen. The interamidine distance in the structure appears to have bearing on antileishmanial activity. The observations made are likely to evoke new understanding on the structure activity relationship of diarylamidines.
Subject(s)
Amidines/chemistry , Animals , Antiprotozoal Agents/chemistry , Cricetinae , Drug Evaluation, Preclinical , Leishmaniasis, Visceral/drug therapy , Male , Mesocricetus , Structure-Activity RelationshipABSTRACT
Impact of change of heteroatom in pentavalent heterocycles, viz., pyrroles, isoxazoles, imidazoles and crotonates on the profile of antileishmanial activity against amastigotes of L. donovani using in vivo test system and macrophage-amastigote culture system has been studied. Sixty-three compounds were tested. Nine imidazoles showed marginal activity in vivo, whereas 3 out of 10 compounds of isoxazolone series and 2 out of 4 substituted aminocrotonates exhibited antileishmanial activity. Of the 30 substituted pyrroles, except 8 all showed antileishmanial activity in vivo on day 7 post treatment.
Subject(s)
Animals , Cricetinae , Heterocyclic Compounds/therapeutic use , Leishmaniasis, Visceral/drug therapy , MaleABSTRACT
The IFA test developed using Leishmania donovani promastigote and amastigote antigens showed very high antibody titre in clinically and parasitologically established cases (30) of kala-azar, the geometrical mean reciprocal titre (GMRT) being 870 +/- 5.4 and 5370 +/- 1.80 respectively with the two antigens. In contrast, the GMRT of normal subjects of endemic area was only 12.44 +/- 6.19 and 80.35 +/- 1.66 respectively with these antigens. None of the subjects from non-endemic area suffering with other parasitic diseases, such as malaria, filaria, amoebiasis, leprosy or tuberculosis (20 cases each) gave a positive response to any of the antigen. The test holds promise in the diagnosis of Kala-azar.
Subject(s)
Animals , Antibodies, Protozoan/analysis , Fluorescent Antibody Technique , Humans , Leishmania donovani/isolation & purification , Leishmaniasis, Visceral/bloodABSTRACT
Antileishmanial activity and organ distribution of the antifungal drug Amphotericin-B in free and liposomised form have been studied in Balb/c mice infected with Leishmania donovani. Results indicate that Amphotericin-B in the liposomised form is significantly more active than the free form. This increase in the activity is perhaps related to the reduced drug toxicity rather than the altered drug distribution at the site of infection.
ABSTRACT
An ultrastructure study was carried out on the effect of a standard drug sodium stibogluconate and a newly identified active CDRI compound 87/305 [1,2-dimethyl-3-methoxy carbonyl-4-(2-nitro-4,5-dimethoxyphenyl) pyrrole] on amastigotes of Leishmania donovani in macrophage cells of spleen of infected hamsters. While Na-stibogluconate exerted its effect by activating the digestion capacity of host macrophages, compound 87/305 was directly lethal to the parasites without, exerting any effect on the host cells.
Subject(s)
Animals , Antimony Sodium Gluconate/therapeutic use , Antiprotozoal Agents/pharmacology , Cricetinae , Leishmania donovani/drug effects , Leishmaniasis, Visceral/drug therapy , Male , Microscopy, Electron , Pyrroles/pharmacology , Spleen/parasitologyABSTRACT
The impact of seasonal variation on the course of L. donovani infection in hamsters was investigated. Though the animals were maintained in controlled climatic conditions (25 degrees C +/- 2), parasites exhibited seasonal rhythm. During summer (April-July) when the atmospheric temperature ranged from 20.5 degrees C to 41.8 degrees C, the parasite load from an inoculum of 1 x 10(7) amastigotes/animal was found to be less than 1 to 9 per 100 cell nuclei (based on spleen biopsy) on day 25-35 post infection. An escalation in count was observed from August onwards, which reached the peak (approximately 30/100 cell nuclei) in February-March (temp. range 11.3 degrees C to 31.4 degrees C). The multiplication rate monitored 15 days after the initial assessment also showed a similar pattern. The secondary organs examined showed no parasites. The study revealed that despite the non-involvement of the vector in experimental infection in hamster, the parasites retained its periodic character as in man, corresponding to cyclicity of vector.
Subject(s)
Animals , Cricetinae , Leishmania donovani/growth & development , Leishmaniasis, Visceral/parasitology , Male , Mesocricetus , Prospective Studies , Seasons , TemperatureABSTRACT
Three methods have been described for cultivation of erythrocytic stages, specially gametocytes of P. berghei NK65 strain, (1) by using vial candle jar where the cultures were subcultured by addition of fresh erythrocytes, (2) a newly designed simple and compact continuous medium flow apparatus, where medium was continuously perfused but fresh erythrocytes were not added and (3) where the subcultures were also done using simple and compact continuous medium flow apparatus for comparison. The maximum percentage of parasitized erythrocytes obtained by these methods was 24.3, 27.1 and 26.4% respectively. Parasites in vials could survive for more than 10 days with 3 to 4 subcultures with maximum 1.96% gametocytaemia. However, the gametocytaemia in continuous medium flow apparatus, where subcultures were not made reached 2.2% compared to that of 2.7% in this apparatus where subcultures were done. The asexual as well as sexual stages of this parasite survived for about 16-18 days in compact continuous medium flow apparatus, where at least 7 subcultures were done.
Subject(s)
Animals , Culture Techniques/methods , Flow Cytometry , Plasmodium berghei/physiologyABSTRACT
A total of 51 imidazoles, pyrroles, quinolines and isoxazolines compounds were screened for antileishmanial activity in vivo and in vitro, using Leishmania donovani as the test parasite. The screening revealed hitherto unknown antileishmanial activity in these heterocycles. Three of the compounds screened (one belonging to isoxazoline series and two from pyrrole series) showed significant anti-leishmanial activity, ranging from 86-91 per cent inhibition in hamsters. When tested in vitro, using macrophage amastigote culture system, these compounds showed inhibition of 62-78 per cent at 30 micrograms/ml concentration.
Subject(s)
Animals , Antiprotozoal Agents/pharmacology , Cricetinae , Heterocyclic Compounds/pharmacology , Leishmania donovani/drug effects , Leishmaniasis, Visceral/drug therapy , MaleABSTRACT
A technique for obtaining isolated luteal cells without any prior enzymatic dissociation of the rat corpus luteum (CL) has been developed. With a view to obviate any kind of chemical/biophysical trauma to the cells the latter were obtained following simple migration of cells from small pieces of chopped up CL (8-10 day old) put in culture. The cells started migrating in progressively increasing numbers from these tissue pieces within 24 hr leading to monolayer formation by day 10-12 of culture. The cells were found to grow under the described conditions for 35 days without any exogenous hormonal supplementation. The technique is being utilized for characterization of different cell types of the rat CL of pregnancy and the regulatory mechanisms involved in their metabolic function and/or regression.