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Biomedical subjects

K Prakash

Publications and source records attributed to K Prakash.

At least 37 records · Page 2Linked to original sources
PubMed1993

Evaluation of phenolic glycolipid-I (PGL-I) antibody as a multidrug therapy (MDT) monitor.

Since phenolic glycolipid-I (PGL-I) is an unequivocal marker for Mycobacterium leprae, this antigen has been a good candidate for the serodiagnosis and monitoring of the effectiveness of leprosy chemotherapy. The present study, a continuation of an earlier report, was undertaken to estimate PGL-I antibody titers in 40 leprosy patients 3 and 6 months after starting MDT. All the leprosy groups showed significant declines in anti PGL-I reactivity after 6 months. There was a good correlation between bacteriological indices (BI) and anti PGL-I antibody levels. Thus, PGL-I based serology may be useful in monitoring the response to multidrug therapy.

Antigens, Bacterial↗
PubMed1993

Altered T and B lymphocytes in multitransfused patients of thalassemia major.

T and B lymphocytes were estimated in 25 patients with Thalassemia major to evaluate their immune status. The percentage of T cells was significantly reduced (p < 0.001) while that of B cells was significantly raised (p < 0.001) in patients of thalassemia major as compared to age and sex matched controls.

B-Lymphocytes↗
PubMed1993

Neisseria meningitidis: serotyping and subtyping by whole cell ELISA.

Twenty strains of Neisseria meningitidis isolated from clinically diagnosed cases of meningococcal disease were subjected to serogrouping, employing slide agglutination followed by serotyping and serosubtyping by whole cell ELISA using monoclonal typing antisera. All isolates were from sporadic cases of meningitis during a period of two years from various hospitals in Delhi. All 20 isolates were grouped as serogroup A and typed as serotype 4, except one strain which was untypable. On serosubtyping the isolates were found to belong to P1.9 (7 strains) followed by P1.1 (5), P1.9 (2), P1.16,1 (2), P1.6,10 (2), P1.10,7,1 (1) and non-subtypable (1).

Animals↗
PubMed1993

Immunological study in pleural effusion.

Thirty patients of pleural effusion (25 tubercular, 5 malignant) were studied for enumeration of T and B cell percentage in pleural fluid (PF) and peripheral blood (PB) along with estimation of IgG, IgA and IgM. Ten healthy subjects were taken as controls. T cell percentage was significantly low and B cell percentage high in the PB of patients with effusion compared with controls. Comparing malignancy and tuberculosis patients it was seen that in both T cells in PF were higher and B cells lower compared with their respective values in PB. Significantly increased percentage of T cells in PF indicates either an active sequestration in PF or the presence of suppressor adherent cells in PB. However, T and B cell percentage in PB and PF were not significantly different in the two study groups. PB immunoglobulin (IgG, IgA, IgM) levels in patients were higher as compared to those in the controls, without significant difference in their levels in the two study groups. Ratio of PF/PB values for various immunoglobulins was less than unity but a cut-off point of 0.6 for IgG & IgA and 0.5 for IgM worked out as pointer for differentiating between malignant and tubercular effusions.

Adolescent↗
PubMed1993

Current status of drug resistance & phage types of Salmonella typhi in India.

A total of 11391 strains of S. typhi were received at the National Salmonella Phage Typing Centre at New Delhi during January 1990- August 1992, from various regions of India. Of these, 39.7 per cent were from north India, 37.5 per cent from central India and 22.8 per cent from south India. 64.5 per cent of S. typhi were found to be multidrug resistant (MDR), maximum resistance being observed in 1991 (71.6%) while it was least in 1990 (50.05%). There was a slight decline in the percentage of MDR strains in 1992. Region-wise analysis of the resistant strains showed maximum number in central India (71.32%), whereas it was least in the south (55.2%); 62.34 per cent of strains received from north India were MDR. Irrespective of the year or region, the predominant resistance pattern remained AMCSXTTE. The commonest phage type was E1, followed by 0 and A. This pattern was also seen in the MDR S. typhi. Certain degraded Vi strains, untypable Vi strains and Vi negative strains were also multidrug-resistant. An important change observed in this study was that a small number of strains belonging to phage types C1, K1, 28, 40, 41 and 42 which were always sensitive earlier, had developed multidrug resistance. Small outbreaks due to one phage type (e.g., 28 and 51) were short lived and subsided spontaneously. More diversity of phage types was observed in north India as compared to central and south India.

Anti-Bacterial Agents↗
PubMed1993

Immunodiagnosis of group-A streptococci by latex agglutination assays with monoclonal or monospecific polyvalent antibodies.

Seven clones of murine monoclonal antibodies specific for group-A streptococci were generated. All of them were of IgM isotypes and recognized trypsinized as well as nontrypsinized group-A streptococci and polysaccharide. These were devoid of reactivity with streptococci-B, -C, -G and Staphylococcus aureus. Polyclonal antibodies against group-A polysaccharide (APS) were also raised in rabbits by linking APS to bovine serum albumin, and rendered monospecific by adsorption. Latex agglutination assays were developed employing both types of antibodies. The assay employing monospecific polyvalent antibodies had a sensitivity of 12.5 ng APS/ml as compared to 1 microgram APS/ml for latex sensitized with monoclonal antibodies. Both assays were specific, as no agglutination was observed with polysaccharides obtained from streptococci-B, -C, -G, Staph. aureus, Cornybacterium diptheriae, Candida albicans, Candida spp., Morexella catarrhalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Streptococcus agalactiae, Strep. pneumoniae. Salmonella typhi and S. paratyphi A and B. Throat swabs from children obtained in duplicate, when tested for the presence of streptococci-A, showed a good correlation of the results obtained by latex agglutination assay with the microbial culture test and serogrouping.

Animals↗
PubMed1992

dOct2, a Drosophila Oct transcription factor that functions in yeast.

Oct factors are members of the POU family of transcription factors that are shown to play important roles during development in mammals. Here we report the cDNA cloning and expression of a Drosophila Oct transcription factor. Whole mount in situ hybridization experiments revealed that the spatial expression patterns of this gene during embryonic development have not yet been observed for any other gene. In early embryogenesis, its transcripts are transiently expressed as a wide uniform band from 20% to 40% of the egg length, very similar to that of gap genes. This pattern progressively resolves into a series of narrower stripes followed by expression in 14 stripes. Subsequently, transcripts from this gene are expressed in the central nervous system and the brain. When expressed in the yeast Saccharomyces cerevisiae, this Drosophila factor functions as a strong, octamer-dependent activator of transcription. Our data strongly suggest possible functions for the Oct factor in pattern formation in Drosophila that might transcend the boundaries of genetically defined segmentation genes.

Amino Acid Sequence↗
PubMed1992

Significance of antibodies to phenolic glycolipid-I in leprosy diagnosis.

A gelatin particle agglutination assay for the detection of anti PGL-I antibodies in 40 clinically diagnosed and variously classified groups of leprosy cases revealed elevated PGL-I antibody titers in 85% of cases. In contrast, the slit-skin smear examination was positive in only 30% of cases. It was further observed that, out of 28 cases with Bacteriological Index (B.I.) zero, 22 cases (78.5%) had significant levels of PGL-I antibodies. There was no case in which the slit skin smear was positive and the PGL-I antibody titer was not significant. The elevated titers of PGL-I antibody better correlated (84%) with histopathological findings than did B.I. Thus it was concluded that estimation of PGL-I antibody titer is a better supplement to clinical diagnosis than B.I. Significant levels of PGL-I antibody were seen in 85% of cases who had no earlier chemotherapy or were treated for less than 2 months. Similar findings were observed in 12 patients who were on MDT for more than 5 months but for less than 2 years. In order to determine the significance of anti PGL-I antibodies in monitoring the response of patients to chemotherapy, a longer follow up with a greater number of cases should be contemplated.

Antibodies, Bacterial↗
PubMed1992

Generation of deletion mutants of simian immunodeficiency virus incapable of proviral integration.

Deletion mutants of simian immunodeficiency virus (SIVmac) which were unable to integrate into host cells were generated by removing a portion of the integrase (IN) domain of the pol gene. The resulting plasmid was transfected into HUT-78 and human rhabdomyosarcoma cells. In comparison with the parental plasmid DNA transfected in parallel, the deletion mutant was found to direct efficient production of virus in both cell systems. Viruses derived from wild-type and mutant proviral DNAs were also tested for their relative replicative abilities in HUT-78 and U937 cells, and the kinetics of virus production was found to vary between these two cell systems. Analysis of DNA from infected cell nuclei showed that the deletion mutant lacked the ability to integrate despite being able to produce infectious virus. Using the sensitive polymerase chain reaction technique, we have clearly demonstrated the absence of the IN domain in the deletion mutant after infection and replication in HUT-78 cells. Such mutants might form the basis for the development of an experimental live attenuated vaccine.

Base Sequence↗
PubMed1992

Subclinical group A streptococcal throat infection in school children.

Seven hundred and forty nine apparently healthy school children aged 5-15 years were investigated for throat infection with Group A streptococci (GAS) during December 1990 to May 1991. The prevalence of beta hemolytic streptococci (BHS) was 18.8%; most organisms belonged to Group A streptococci (13.7%). The prevalence of BHS in throat was significantly higher (p < .001) in girls as compared to boys. Immune response to extracellular antigens was studied in 53 children who had GAS strain in their throat, 54.7% had elevated titers of antistreptolysin O or antideoxyribonuclease B or both indicating subclinical infection with GAS. Thus it is recommended that serological examinations should be done along with throat culture to identify subclinical Group A streptococcal throat infection.

Adolescent↗
PubMed1992

Streptococcal throat carriage in school children with special reference to seasonal incidence.

A number of studies on throat carriage of beta hemolytic streptococci (BHS) carried out during the years 1972-90 in urban and rural school children from low socioeconomic groups in the age group of 5-15 years in and around Delhi showed an overall carriage rate of BHS varying from 12.2%-64.3% depending upon the season and number of swabs taken. Group A was found to be the most predominant serological group (31.1%-62.6%). The T-typability was found to be 98.2%. The most prevalent T-patterns observed during 1972-78 study were 3/13/B3264 followed by 5/11/12/27/44. A significant difference was observed in the prevalence of T-patterns during the study of 2,034 children from 1979-83 and 3,094 children from 1984-90. When the most prevalent T-patterns were found to be 5/11/12/27/44 followed by 3/13/B3264. The study of the school children from 1972-90 showed the isolation of BHS as well as significant predominance of GAS (p < 0.001) in winter months than summer months. There was no difference in the distribution of carriage of BHS and GAS amongst rural or urban school children. Since RF/RHD are illnesses which were often encountered in school children among socially and economically disadvantaged populations stronger support for streptococcal surveillance programs should be encouraged.

Adolescent↗
PubMed1992

Auxotyping of Neisseria gonorrhoeae as an additional epidemiological marker.

Auxotypes and penicillin sensitivity of 102 strains of N. gonorrhoeae were studied. Ten distinct auxotypes on the basis of growth requirement to seven amino acids were observed. The commonest pattern seen was zero auxotype (33.3%), followed by auxotype requiring proline (18.6%). MIC of 72 (71.5%) strains ranged from < 0.003 IU/ml to 0.062 IU/ml of benzyl penicillin. MIC of the other 30 (29.5%) strains was found to be > or = 0.125 IU/ml, indicating penicillin resistance. None of the strains were penicillinase producers. A case of reinfection was also detected on the basis of change in auxotype pattern.

Amino Acids↗
PubMed1992

Clinical and bacteriological study of normal and inflamed neonatal conjunctivae.

Maternal vaginal and neonatal conjunctival flora were prospectively studied in a 117 mother baby pairs. The commonest isolates from both vaginal and conjunctival flora were E. coli, Staphylococcus aureus and Klebsiella species. In 85% of mother-baby dyads, isolates from vagina and conjunctiva were similar. The commonest bacterial isolates in neonates with conjunctivitis were Staphylococcus aureus (37.4%), E. coli (27.9%) and Klebsiella species (19.3%). Maternal coitus, infections, rupture of membranes and baby's birth weight and sex did not influence the occurrence of conjunctivitis.

Bacteria↗
PubMed1991

Isolation and characterization of an infectious molecular clone of the MN strain of HIV-1.

Infectious molecular clones of the human immunodeficiency virus (HIV) have been very important tools for the analysis of regulatory gene functions and the study of differential cell tropism. We have cloned and characterized a proviral sequence of HIVmn from mn strain infected H9 cells. This clone, called KP1, was found to be infectious for different cell lines and human peripheral blood lymphocytes (PBL). KP1 proviral DNA was detected in HUT-78 cells and human PBL by polymerase chain reaction (PCR) analysis after infection of these cells with cell-free supernatants from KP1 transfected human rhabdomyosarcoma (RD) cells. To the best of our knowledge, this is the first report of an infectious molecular clone of HIVmn which is a representative of one of the most prevalent strains of HIV-1 in North America and Europe. Biologically active clones of a broadly antigenic strain such as HIVmn will be extremely useful in therapeutic approaches for AIDS.

Base Sequence↗
PubMed1991

Isolation and characterization of newborn rabbit brain-derived microglia.

We isolated brain microglia from newborn rabbits and maintained these cells in in vitro culture. Enriched populations of rabbit microglia share several characteristics of mononuclear phagocytes including intracellular staining for nonspecific esterase and acid phosphatase. Microglia express Fc receptors, generate superoxide anion, and stain positive with the lectin Ricinus communis. Rabbit brain microglia develop multinucleated giant cells and small colonies in in vitro culture. The cells are highly phagocytic in culture. Other investigators have recently demonstrated that rabbits can be infected with HIV-1 in vivo and that neurological symptoms occur only when HIV-1 infection was carried out in HTLV-1-infected rabbits. Brain microglia most likely play a central role in HIV-1 encephalopathy. The availability of rabbit brain microglia in in vitro culture, offers a valuable potential cell model to study HIV-1 infection in the central nervous system.

Animals↗