Dose-dependent differential effect of hemin on protein synthesis and cell proliferation in Leishmania donovani promastigotes cultured in vitro.

Leishmania donovani requires an exogenous source of heme for growth and transformation. In in vitro culture of the free-living promastigotes, exogenously added hemin enhances cell proliferation. In this investigation, the question of the function of heme with particular reference to protein synthesis and cell proliferation has been addressed. The results of in vitro cell culture experiments demonstrated that hemin (10 microM) alone is suitable for supporting optimum level of protein synthesis, and thereby cell proliferation of promastigotes to an extent that it can replace fetal bovine serum. However, in situ labelling experiments along with Western blots revealed that high concentration of hemin (50 microM) reduced the level of protein synthesis in general and of beta-tubulin in particular with a concomitant induction of hsp90, and induced consequent morphological changes that are observed during in situ transformation of promastigotes in mammalian macrophages. These results therefore suggest that sudden exposure to high concentration of heme in mammalian macrophages may be one of the key factors that trigger promastigote to amastigote transformation in L. donovani. Furthermore, hemin with its dual characteristic could be used as a tool to understand molecular mechanism of cell proliferation and transformation in these parasites.

Cytokeratin expression in human fetal tongue and buccal mucosa.

Expression of cytokeratins (CK), a subset of intermediate filament (IF) proteins in epithelia, is developmentally regulated. CK expression may also change after malignant transformation. Our earlier studies on CK expression in human oral tumours and pre-cancerous lesions have shown specific changes in CK expression. We analysed CK expression in human tongue and buccal mucosa (BM) in fetuses in the embryonic age group of 16 to 27 weeks using biochemical and immunohistochemical techniques to find out whether there is any similarity in CK expression in human oral squamous cell carcinomas (SCC) and fetal oral tissues. CK 1, 8 and 18 were detected in a majority of samples using both techniques. Our earlier studies had shown aberrant expression of CK 1 and 18 in many of the oral SCC and leukoplakias. Studies by immunohistochemistry showed that these different CK antigens were expressed in different cell layers. CK 1(2) were present in the stratified epithelial layers whereas CK 8 and 18 were restricted to glandular epithelium. Till 27 weeks of gestation, both tongue and BM expressed CK 1, 8 and 18 along with CK 6 and 16. Thus, fetal tissues showed some similarities in CK pattern with their respective SCC.

Assessment of transcervical chorion villus aspiration biopsy in early pregnancy.

BACKGROUND. Chorionic villus sampling for prenatal diagnosis is a relatively new technique and variable success rates have been reported by different authors depending on the methods and instruments used. We describe our experience with chorionic villus sampling in Bombay. METHODS. The procedure was attempted on 62 women before termination of their pregnancy via the transcervical route, under constant real-time ultrasound guidance. A metallic cannula was negotiated through the cervix into the uterine cavity to reach the chorionic frondosum and chorionic villi were aspirated by creating a negative pressure in the syringe attached to the cannula. The villus tissue was checked under a dissecting microscope. We calculated the success rate for obtaining a sample depending on the site of the chorionic frondosum, the physique of the mother, the position of the uterus and the size of the cannula. RESULTS. Villus tissue was aspirated in 47 of the 62 cases. The success rates of sampling at the first and second attempts were 48% and 27% respectively. The factors which were associated with a higher success rate were when the chorionic frondosum was situated posteriorly rather than anteriorly (61% v. 48%; p < 0.01), when the patient was thin rather than fat (58% v. 25%; p < 0.001), when the uterus was anteverted rather than retroverted (53% v. 41%). The commonest complication was bleeding which occurred in 15% of patients. CONCLUSION. Transcervical chorionic villus sampling is associated with a high success rate except in fat women with a retroverted uterus and in those with the chorionic frondosum situated in the fundus.

Post-puerperal Cu-T insertion: a prospective study.

One hundred and sixty eight consecutive women accepting copper T (CuT) intrauterine contraceptive device in the post-puerperal period were studied. Out of them, 63 could be followed after 6 weeks of insertion and 65 after 6 months of insertion. The risk of heavy bleeding, pain in abdomen etc. were no greater than those usually found when interval CuT insertion is carried out. There was no case of uterine perforation leading to migration of CuT. But the expulsion rate was found to be high i.e. 16.4%. CuT is a very useful post-puerperal contraceptive method and should be given more importance in MCH programme.