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V Vijayalakshmi

Publications and source records attributed to V Vijayalakshmi.

16 recordsLinked to original sources
PubMed2006

Stem cell test: a practical tool in toxicogenomics.

During early embryonic development, at blastocyst stage, the embryo has an outer coat of cells and an inner cell mass (ICM). ICM is the reservoir of embryonic stem (ES) cells, which are pluripotent, i.e., have the potential to differentiate into all cell types of the body. Cell lines have been developed from ES cells. In addition, there are embryonic germ (EG) cell lines developed from progenitor germ cells, and embryonic carcinoma (EC) cell lines developed from teratomas. These cell lines are being used for the study of basic and applied aspects in medical therapeutics, and disease management. Another potential of these cell lines is in the field of environmental mutagenesis. In addition to ES cells, there are adult stem cells in and around different organs and tissues of the body. It is now possible to grow pure populations of specific cell types from these adult stem cells. Treating specific cell types with chemical or physical agents and measuring their response offers a shortcut to test the toxicity in various organ systems in the adult organism. For example, to evaluate the genotoxicity of a chemical (e.g., drug or pesticide) or a physical agent (e.g., ionizing radiation or non-ionizing electromagnetic radiation) during embryonic development, a large number of animals are being used. As an alternative, use of stem cell lines would be a feasible proposition. Using stem cell lines, efforts are being made to standardize the protocols, which will not only be useful in testing the toxicity of a chemical or a physical agent, but also in the field of drug development, environmental mutagenesis, biomonitoring and other studies.

Cell Differentiation↗
PubMed2005

Fluorescent amplified fragment length polymorphism (FAFLP) based molecular epidemiology of hospital infections in a tertiary care setting in Hyderabad, India.

Bacterial isolates from respiratory and urinary tract infections in an Indian hospital setting were genotyped using FAFLP analysis. The 77 different isolates analyzed belonged to five genera namely Escherichia, Staphylococcus, Pseudomonas, Enterobacter and Pantoea. Before carrying out FAFLP analysis all the isolates were subjected to16S-23S ribosomal RNA-based species identification. Cluster analysis of FAFLP profiles of 77 isolates generated five groups corresponding to five bacterial genera that are used in the study. Further analyses of the dendrograms revealed efficient species and strain differentiation. Cluster analysis identified genetically distant clones among the clinical isolates of Staphylococcus aureus, two distinct genetic lineages among the Escherichia coli strains and a single cluster of closely related Pseudomonas aeruginosa isolates. Ribosomal spacer region amplification identified different species accurately but intraspecies discrimination could not be accomplished completely. Comparison of FAFLP profiles of our isolates, with a pilot database of validated strains, was very useful in identification and worked better in conjunction with dendrogram analysis.

Bacterial Typing Techniques↗
PubMed2004

Comparison of biochemical and cytotoxic functions of hepatocytes from goat, pig and human fetuses.

BACKGROUND AND AIM: To overcome the problem of shortage of donor organs, xenotransplantation of cells offers an alternative to orthotopic transplantation. Of the higher animals, the pig is considered as a suitable donor because of the similarity in size and function of pig organs to human organs. However, successful transplantation of pig organs/cells for human therapy is limited by hyperacute rejection, improper functioning of xenografts and the risk of transmission of endogenous retroviruses to the recipient. Thus, there is a pressing need to explore an alternate mammalian source to bridge the gap between the donor and the recipient waiting for transplantation. This has warranted us to explore the application of goat hepatocytes as a treatment modality in acute liver failure. METHODS: In the present investigation, isolated goat hepatocytes were assessed for their viability, membrane integrity, synthetic and cytotoxic functions, and compared with the hepatocytes of pig and human fetuses (28-36 weeks). RESULTS: The isolated hepatocytes from goat, pig and human fetuses were comparable in their viability, membrane integrity and synthetic functions. However, the cytotoxic functions assessed using 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide assay demonstrated a significant reduction in the viability of the pig hepatocytes (38%) as compared with the goat and human fetal hepatocytes, which retained their viability (98%) on incubation with normal human serum. CONCLUSION: These observations are significant as they suggest that goat hepatocytes probably can be explored as a source for cell therapy in the treatment of acute liver failure.

Analysis of Variance↗
PubMed2000

BCG vaccine--current status.

Tuberculosis incidence has made re-emergence due to multidrug resistance of the bacilli and for acquired immunodeficiency syndrome. Of all vaccines BCG is most widely used. It protects children from secondary forms of tuberculosis. Several authors recommend a second dose to boost the waning effect of BCG. The vaccine at present needs to be improved to make it more efficacious. Vaccines which involve the protective immune responses are ideal.

BCG Vaccine↗
PubMed1998

Cell mediated immunity in children with scar-failure following BCG vaccination.

OBJECTIVE: To find out the incidence of BCG-scar failure, in BCG vaccinated children and assess their in vitro cellular response. DESIGN: Four year prospective cohort observational study. SETTING: Immunization centers at: (a) State Tuberculosis Center; (b) Tuberculosis Association of Andhra Pradesh; and (c) Niloufer Hospital for Women and Children in Hyderabad. METHODS: Healthy children brought to the immunization centers for BCG vaccination and were followed up till 6 months of age for scar failure. These 655 BCG vaccinated children were classified into three groups based on the age at vaccination: (i) 0 day-1 day; (ii) 2 days-30 days; and (iii) 31 days-90 days. Of these children, in vitro leukocyte migration inhibition (LMI) levels against PHA/PPD were investigated in 228 of them. RESULTS: Of the 655 children, 591 (90.2%) showed presence of scar. Out of the three groups, number of children belonging to the first group in whom the scar was absent, was highest. Of 591 children with scar, LMI was performed in 34, 110 and 43 of them in the three different age groups, respectively out of whom 88.2%, 87.2% and 86% had positive response (> or = 20%) to PPD. Of 64 children who failed to develop a scar, LMI was performed in 17, 19 and 5 in three different age groups out of whom 88.2%, 94.7% and 80% had positive (> or = 20%) in vitro response to PPD. CONCLUSION: Scar failure may occur in 10% of BCG vaccinated and is more common with immunization within 48 hours of life. Failure of formation of BCG-scar at the site of BCG vaccination may not necessarily imply failure of immunization because majority of them do elicit positive in vitro LMI response.

Age Distribution↗
PubMed1997

Role of transglutaminase in keratinization of vaginal epithelial cells in oestrous cycling rats.

Aspects of the regulation of calcium dependent transglutaminase (TGase) enzyme in the terminally differentiating vaginal epithelial cells (VEC) from cycling and oestradiol primed ovariectomized (OVX) rats are described. There is a significant increase in the TGase activity and a quantitative rise in its cross-linked sigma(tau-glutamyl)lysine covalent product in the VEC of oestrus rats. A similar phenomena was also evident in the oestradiol primed OVX rats. However, in the VEC of the diestrus/unprimed OVX rats, the enzyme activity and its cross-linked product tend to be at its basal level. An increase of TGase activity in the keratinized layers of the oestrus VEC was observed. Immunohistochemical localization data parallel the biochemical measurements. These findings suggest that TGase activity may be associated with the differential status of the cell and primarily aids in the conferring structural stability and integrity to the stratified VEC. Aggregates of the keratin tonofilament bundles which are covalently cross-linked by the formation of sigma(tau-glutamyl)lysine in the oestrus vagina renders them resistant to denaturant and proteolytic treatments.

Animals↗
PubMed1996

Crossmatching considerations in renal transplantation.

During the year 1993-1994, 73 renal transplant cases have been screened for the presence of anti-HLA antibodies using the standard lymphocytotoxicity assay. Amongst the 9 related transplantations with 100% negative crossmatch 6 were successful. About 8.2% of the patients had a shift from positive to negative crossmatch. It was observed that an increased number of transfusions (ranging from 3 to 21) in males and females yielded negative crossmatches. In females, however, owing to various factors such as pregnancies, parity and infections, varied percentages were observed with different donors. The crossmatches in diabetics and hypertensive patients suggest no particular correlation and probably have no role in the outcome of the assay.

Blood Transfusion↗
PubMed1995

Comparison of the immune responses in children vaccinated with three strains of BCG vaccine.

The present study was conducted to evaluate and compare the specific cellular responses of children vaccinated with three different strains of BCG. The study comprised of normal children with normal weight and normal general responses (PHA) to in vitro leukocyte migration inhibition test (LMIT). The three strains of BCG under study were Japan-BCG, Glaxo-BCG and Madras-BCG. One hundred children were selected at random from each group. The mean ages of these infants were 9.9 +/- 9.5, 9.8 +/- 7.6 and 9.8 +/- 8.3 weeks, respectively. Six weeks after vaccination, the diameter (in mm) of induration at the vaccination site was measured. Three months after vaccination, in vitro LMIT was performed against PPD tuberculin antigen. This test was done again after 3 months in all the children who tested negative. The mean value of the diameter of the Glaxo-BCG group (10.0 +/- 13.5 mm) was significantly higher (p < 0.05) than the mean values of Japan-BCG (9.10 +/- 3.9 mm) and Madras-BCG (8.38 +/- 4.1 mm). The mean LMI values were similar in all the three groups. There was no correlation between the in vitro and in vivo parameters. The number of children positive to LMI (PPD) were 59, 58 and 63, for the Madras, Japan and Glaxo-BCG groups, respectively. A total number of 91, 91 and 95 were positive to LMIT at the end of 6 months after BCG in the Madras, Japan and Glaxo-BCG groups, respectively. The observations suggested that there were no major differences between the three strains of BCG in their capacity to induce cellular responses.

Analysis of Variance↗
PubMed1995

Immunology of AIDS.

Explore the source record for details and available documents.

AIDS-Related Opportunistic Infections↗
PubMed1994

Estradiol-regulated transamidation of keratins by vaginal epithelial cell transglutaminase.

We have observed a marked increase in the activity of transglutaminase (EC 2.3.2.13) in rat vaginal epithelial cells in a time-dependent manner during estradiol-induced terminal differentiation. The increased transglutaminase activity facilitates a post-translational modification, transamidation of keratins by the formation of an isopeptide sigma (tau-glutamyl) lysine. This isopeptide was recovered from the urea-soluble and -insoluble fractions of keratins. The formation of sigma (tau-glutamyl) lysine was significantly reduced in rats primed with progesterone or tamoxifen-estradiol. These in vivo experiments were further confirmed by in vitro studies using the reconstituted keratin filaments, which demonstrated a remarkable acceleration in the formation of covalent cross-links mediated by vaginal epithelial cell transglutaminase obtained from rats primed with estradiol. By specifically modifying the lysine residues of the keratins with 2,4-pentanedione the aggregation of keratin filaments was inhibited. These findings reflect that the vaginal epithelial cell transglutaminase obtained from rats which is regulated by estradiol plays a key role in the process of terminal differentiation of rat vaginal epithelial cells.

Amides↗
PubMed1994

Association of transglutaminase with the reconstituted keratin filaments isolated from rat vaginal epithelial cells.

We report a novel association of the calcium dependent cross-linking enzyme, transglutaminase (TGase) with the urea soluble reconstituted keratin filaments (RKF) isolated from the rat vaginal epithelial cells (VEC). This was ascertained by measuring the activity using 14C-spermidine incorporation and also by an increase in keratin filament aggregation by the addition of only TGase cofactor-calcium. These events were specifically inhibited by the treatment of calcium chelator, EDTA at a concentration > 2 mM as well as by pretreating the RKF with histamine, a TGase substrate inhibitor. The association was also exemplified by immunoblotting analysis where a specific and preferential polypeptide of molecular weight 58 kDa cross-reacted with TGase antibody amongst the other keratins. This phenomenon was not seen in the keratins isolated from skin, a non-targeting tissue for estradiol action.

Actin Cytoskeleton↗
PubMed1994

Optimum age of a child for BCG vaccination.

The objectives of this study were to evaluate whether a newborn or a neonate is capable of responding immunologically after BCG vaccination and to find out if this immunity persists for one year. Normal infants aged between 0 days-3 months brought to immunization centre were included in the study. In vitro leukocyte migration inhibition test was performed in these children using Phytohemagglutinin and purified protein derivative (PPD). They were grouped based on their age at vaccination, their LMI values and on the time interval after vaccination. The mean values of % LMI (PPD) in all the age groups were positive and there were no significant differences between the newborns, the neonates and other groups. The values were positive and comparable even after 12 months in all the groups. The percentage of infants with positive or negative values to LMI (PHA) and negative values to LMI (PPD) were also comparable at different time intervals in different age groups. The results suggest that newborns or neonates are as capable of eliciting a positive immune response after BCG vaccination, as older infants and the practise of vaccinating a child at birth could be continued.

Age Factors↗
PubMed1993

Cell mediated immune responses in BCG vaccinated children.

The immunological status of BCG vaccinated and unvaccinated healthy children was evaluated to assess the efficacy of BCG. The duration of immunity conferred by the vaccine was also investigated. Of the 326 children studied, 170 (52%) had the BCG scar and only 24 (14%) showed a positive Mantoux response. Among the unvaccinated group, 14 of 156 (9%) showed a positive response. All cases had normal proportions of T and B cells in the peripheral blood. The mean values of the leukocyte migration inhibition (LMI) test with PHA were also normal. The per cent LMI values against PPD were compared in the children classified into groups based on their vaccination status and response to Mantoux test. A higher number of the vaccinated children had positive LMI values compared to those unvaccinated (p < 0.01). The LMI values of children classified into three age groups decreased significantly (p < 0.01) with increase in age. Hence, BCG seems to afford some protection in children and has to be administered at birth. Revaccination at the age of eight years, may boost the waning immunity and, may be considered in this age-group.

Adolescent↗