Hot-water extracts of 7 plants of the family Saxifragaceae; Hydrangea macrophylla var. Otaksa, H. macrophylla, H. macrophylla serrata var. acuminata, H. involucrata, H. hirta, H. paniculata, and Cardiandra alternifolia, were screened for antimalarial activity in ICR mice infected with Plasmodium yoelii 17XL. The leaf extract of H. macrophylla var. Otaksa or H. macrophylla had an antimalarial activity against rodent malaria, showing low parasitemia levels during administration. Following a transient recrudescence of malaria parasites in the bloodstream of treated mice, no parasites could be detected by a microscopic examination. Mice treated with the leaf extract of H. macrophylla var. Otaksa or H. macrophylla survived during the experiment, though mice in the non-treated control and other treated groups died with a gradual body weight loss from day 6 to day 10 post infection. Furthermore, the antimalarial activity of the hot-water extract of H. macrophylla leaf extract seemed higher than that of H. macrophylla var. Otaksa leaf extract in respect of the degree of suppression of parasite multiplication and of mouse body weight loss.

View full abstract

An indigenous rapid immunochromatographic test Parachek-F for diagnosis of Plasmodium falciparum malaria was evaluated by the field staff in a post-monsoon P. falciparum malaria outbreak in villages of district Raichur, Karnataka, South India in November 1999. The test functions based on dipstick P. falciparum histidine rich protein-2 (PfHRP-2) antigen capture assay. Of the 232 uncomplicated clinically diagnosed malaria cases, 158 (68.1%) were positive for malaria by microscopy of JSB-stained thick blood smears. Of these, 13 were infected with P. vivax, 140 with P. falciparum and 5 had mixed infections of P. vivax and P. falciparum. Malaria patients were treated with age-specific oral doses of quinine followed by primaquine. Taking microscopy as gold standard, Parachek-F detected PfHRP-2 antigen in 136 samples (ratio 0.93) and was 93.1% sensitive and 98.8% specific. Positive predictive value, negative predictive value and efficacy were 99.2%, 89.6% and 95.2% respectively. No cross reactivity was observed with P. vivax infection. False negative interpretation was associated in 40% (10/25) lower-grade parasitaemias (parasitaemia <100/p/ blood) where sensitivity was only 60%. False positive result was associated in 1 case (1/74). Cases showing false negative results had taken presumptive treatment with chloroquine prior to the test. Careful microscopical examination on thin smears of such cases demonstrated that the morphology of the parasites was abnormal and distorted indicating the parasites were affected by chloroquine. The possible role of chloroquine resulting false negative results is suggested in this communication. Positive correlation between test bands intensity and parasite density was observed (r=0.137; P<0.05). The test is indigenously developed, rapid, simple in its application and was found suitable for field condition. Parameters like patients' conditions, history of drug intake, morphology of parasites at different developmental stages are to be considered for evaluation of such tests.

View full abstract

We produced antigenic peptide of Trichinella spiralis newborn larvae (NBL) which seemed to be a part (approximately one fourth) of myosin heavy chain, and some basic profiles were revealed. The cDNA library was constructed from NBL and immunoscreened with an antibody against the parasite. A clone, designated NBL21, was selected. It contained a cDNA transcript of 1656 by in length, which encoded 552-amino acids (64868 Da in the estimated molecular weight). The fusion protein encoded by the clone NBL21 was produced in an Escherichia coli expression system and affinity purified. NBL21 fusion proteins migrated at 64 kDa and reacted to T spiralis infected mouse sera and the antibody against NBL crude antigen. Antisera were developed against NBL21 fusion proteins, which reacted to a single band migrating at 200 kDa on Western blotting analysis of crude extracts from muscle larvae, and reacted to hypodermal muscles of T spiralis on immunohistochemical staining. The antigen was recognized by the mouse serum obtained from the early phase of infection, but the antigenicity was devoid of species specificity.

View full abstract

The inappropriate use of anti-tuberculosis drugs has resulted in an increase in the drug resistance. This study was conducted to obtain data related to the spectrum of drug resistant Mycobacterium tuberculosis. A total of 499 strains ofM. tuberculosis were tested for susceptibilities of isoniazid (INH), rifampicin (RFP), ethambutol (EMB) and streptomycin (SM). Totally 225 patients were also evaluated for their clinical manifestations. The primary and acquired resistances were observed in 13.9% and 16.1% to INH, 11.1% and 12.9% to RFP, 6.7% and 9.7% to EMB, and 3.8% and 3.2% to SM respectively. There were no significant differences between primary and acquired resistances. Multi-drug resistance was observed in 22 strains (4.4%). Clinical manifestation, as measured by chest roentgenograms, was similar in patients with either drug-susceptible or resistant strains. The clinical and radiological information was not useful for the prediction of susceptible and resistant strains. The HIV serostatus was not associated with drug susceptibility profiles either. Our study has documented a high incidence of drug resistant M. tuberculosis, with no obvious clinical correlates, which must be considered when implementing a strategy for chemotherapy. As for clinical practices, many defaults during chemotherapy reduced the treatment successes. It is important to assess the efficient implementation of the directly observed treatment with short course chemotherapy (DOTS) and interrupt the further dissemination of resistant M. tuberculosis in the community. The drug resistances must be surveyed continuously to obtain useful clinical perspective and evaluate the effectiveness of tuberculosis control program.

View full abstract