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Biomedical subjects

R Kulshreshtha

Publications and source records attributed to R Kulshreshtha.

At least 19 recordsLinked to original sources
PubMed2005

Structural characterization, expression analysis and evolution of the red/far-red sensing photoreceptor gene, phytochrome C (PHYC), localized on the 'B' genome of hexaploid wheat (Triticum aestivum L.).

Phytochromes are a family of red/far-red light perceiving photoreceptors. The monocot phytochrome family is represented by three members, PHYA, PHYB and PHYC. We have isolated and characterized the first PHY gene member (TaPHYC) from common wheat, Triticum aestivum var. CPAN1676. It codes for a species of the photoreceptor, phyC, which is known to be light-stable in all plants analyzed so far. A sequence of 7.2 kb has been determined, which includes 3.42 kb of coding region. This is the second full-length PHYC gene sequenced from a monocot (first was from rice). TaPHYC gene shares structural similarities with the rice PHYC containing four exons and three introns in the coding region. The 5' UTR is 1.0-kb-long and harbors an upstream open reading frame (URF) encoding 28 aa. Southern blot analysis of TaPHYC indicates that it represents single locus in the wheat genome, although the possibility of additional loci cannot be completely ruled out. Chromosomal localization using nullisomic-tetrasomic lines of Triticum aestivum var. Chinese Spring places TaPHYC on chromosome 4B. PHYC represents a constitutively expressed gene in all the organs tested and under light/dark conditions. However, PHYC was found to be developmentally regulated showing maximal expression in 3-day-old dark-grown seedlings, which declined thereafter. In silico analysis has also been done to compare TaPHYC gene with the partial sequences known from other wheat species and cultivars. The presence of a topoisomerase gene immediately downstream of the PHYC gene, both in rice and wheat genomes, presents yet another example of synteny in cereals and its possible significance has been discussed.

Amino Acid Sequence↗
PubMed2000

An enzyme immunoassay for detection of Japanese encephalitis virus-induced chemotactic cytokine.

Japanese encephalitis virus (JEV) induces human peripheral blood monocytes to secrete a chemotactic cytokine [human macrophage-derived factor (hMDF)] which causes chemotaxis of neutrophils. The only known assay for hMDF cannot quantify its level in samples, so an enzyme immunoassay has been standardized for detection of hMDF and hMDF-specific antibodies in test samples. The reported enzyme linked immunosorbent assay (ELISA) was found to be sensitive (89%), specific (91%), accurate (92 2%) and reproducible and was able to detect a minimum concentration of 23 ng hMDF/ml in test samples. The chemotactic factor could be detected in JEV inoculated mouse sera and JEV infected culture fluids. Significant finding of the test was the detection of hMDF in sera of human cases of JE.

Animals↗
PubMed1999

Predictors of posttraumatic convulsions in head-injured children.

The purpose of this study was to determine predictors of posttraumatic convulsions in children. Study subjects included children under 12 years of age, who were admitted to the Safdarjang Hospital, New Delhi, during the year 1997 (January to December) after suffering head trauma. The occurrence of first convulsion after head injury was taken as the outcome variable in the study. Medical records were reviewed for data about clinical, radiological and epidemiological features of such children. The study revealed that children younger than 2 years of age (odds ratio, OR 2.96; 95% confidence interval, CI 1.42-6.21), those suffering severe head injuries, i.e. with low Glasgow Coma Score (OR 3.07; 95% CI 1.40-6.77), and those with longer period of unconsciousness after head trauma, especially longer than 12 h (OR 1.71; 95% CI 0.69-4.19) have higher likelihood of suffering convulsions after head injury. However, none of the radiological findings were found to be significantly associated with posttraumatic convulsions.

Age Factors↗
PubMed1996

Cryptococcosis associated with HIV negative Indian patients and HIV positive Indian blood donors.

Cryptococcosis, particularly cryptococcal meningitis (CM), has become an increasing problem globally in the AIDS era. In the present investigation we have made an effort for the first time to study Indian cases (100) both HIV-positive (23 cases, male, mostly Indian professional blood donors, PBDs') confirmed by an ELISA test and Western Blot but asymptomatic for CM and HIV-negative (77:49 male and 28 female) asymptomatic or symptomatic. These subjects were patients from the Lucknow hospitals admitted during the period between February, 1991 to February, 1994, for suspected cryptococcosis or CM. Of those cases, 10% were positive for cryptococcosis or CM. Meningoencephalitis was the dominant clinical manifestation in four (HIV-negative) cases of CM. CT scanning of the head of those cases revealed a noncommunicating hydrocephalus due to aqueductal stenosis (in 2 cases) and a communicating hydrocephalus with granuloma (by MRI) in another case. The latex agglutination test (LAT) of the sera was positive for Cryptococcus antigen in 6 (26%) of the (HIV-positive) patients and 4 (5%), of the HIV-negative cases. In the cases of CM, there was a lower antigen titre in CSF than in the pronase-treated sera. The LAT was found to be useful in diagnosis of cryptococcosis, especially in asymptomatic cases. The CSF of CM-positive cases revealed low levels of glucose, reduced cell count and high proteins. Among the HIV-negative cases, the onset of meningitis in 4 cases was preceded by the presence of encapsulated budding yeast cells in CSF India ink smear, or cryptococci in a direct urine smear in one case. The CSF culture of 3 cases was positive for mucoid Cryptococcus neoformans, showing brown colour effect (BCE) on Staib agar (syn. Guizotia abyssinica creatinine agar, bird seed agar). The isolated yeast strains were identified as C. neoformans var. neoformans by physiological tests. The pathogenicity test of strains revealed virulence to BALB/c mice evidenced by a high mortality of mice and significantly (p < 0.05) high CN burden (> 4-5 mean log(10) cfu), in the brain followed by other visceral organs (lung, liver, spleen, kidney and heart). The in-vitro susceptibility (MIC mu gmL(-1)) of strains.

AIDS-Related Opportunistic Infections↗
PubMed1996

HIV-2 prevalence in Uttar Pradesh.

Serum samples collected since 1989 with various patterns of reactivity for human immunodeficiency virus (HIV)-1, on the basis of screening ELISA and confirmatory Western blot (WB) test, were subjected to the detection of HIV-2 infection based on screening dot immunoassay and confirmatory WB for HIV-2. Significant prevalence of HIV-2 infection was (37.03%) among sera reactive for HIV-1 by ELISA but indeterminate by Western blot, compared with sera reactive for HIV-1 by ELISA and WB (3.29%) or negative by WB (2.63%). Out of 16 HIV-2 positive sera, 5 (31.25%) showed evidence of concomitant HIV-1 infection. This study demonstrates evidence of HIV-2 infection as early as 1989, earlier than reported so far from India.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Viruria during acute Japanese encephalitis virus infection.

In this study, viruria following Japanese encephalitis virus (JEV) infection in mice has been shown to appear earlier in pregnant than in normal mice with proteinuria and haematuria. This was related to the production of splenic macrophage derived neutrophil chemotactic factor (MDF) following JEV infection. Intravenous inoculation of MDF in mice resulted in leakage of cells, proteins and erythrocytes in the urine as a result of altered capillary permeability. The isolation of virus from kidney did not correlate with the shedding of virus in the urine. The histological examination of sections of kidneys showed no morphological damage; however, ultrastructural degenerative changes in the mesangial cells were observed following JEV infection. These data suggest that JEV-induced macrophage derived factor regulates the leakage of proteins, erythrocytes and cells into the urine.

Acute Disease↗
PubMed1991

Japanese encephalitis virus latency in peripheral blood lymphocytes and recurrence of infection in children.

In a study group of 40 children who had been admitted to hospital with acute encephalitis, the disease was due to infection with Japanese encephalitis virus (JEV). Three children developed recurrence of disease 8-9 months later. No virus had been isolated from these three patients during the acute stage of their illness, but virus was recovered from all during the recurrence phase by co-cultivation of their peripheral blood mononuclear cells in primary mouse embryo fibroblast cultures. Virus was also recovered by co-cultivation of peripheral blood mononuclear cells collected 8 months after their acute disease from three out of eight randomly selected asymptomatic children within the study group but not from similar cultures set up from JEV-seronegative children used as controls. Virus was also isolated by co-cultivation of T lymphocytes of asymptomatic children as detected by indirect immunofluorescence or by inoculation in mice.

Cells, Cultured↗
PubMed1990

Rapid diagnosis of Japanese encephalitis by immunofluorescent examination of cerebrospinal fluid.

An indirect immunofluorescent technique for rapid diagnosis of patients of Japanese encephalitis (JE) was developed by demonstrating the viral antigen in CSF cells. The CSF samples of 31 consecutive patients admitted with acute viral encephalitis during 1987 were studied. In 15 patients the diagnosis of JE virus infection was made on the same day. Classical techniques for virus detection and antibody serology were also conducted in these patients. The indirect immunofluorescence for JE virus antigen detection in CSF cells proved to be a rapid and simple procedure for making a quick diagnosis of infection.

Acute Disease↗
PubMed1989

Evidence for latency of Japanese encephalitis virus in T lymphocytes.

Activation of latent Japanese encephalitis virus (JEV) in the spleen has been studied by co-cultivation with allogeneic or syngeneic cells. Activated virus was isolated by co-cultivation from T lymphocytes of spleen, as shown by indirect immunofluorescence or by inoculation into mice. The B lymphocytes and macrophages of latently infected mice did not reactivate the virus. A higher proportion of Lyt 1 cells than Lyt 2 cells were harbouring JEV as shown by indirect immunofluorescence. The spleen cells from latently infected mice elicited the lymphoproliferative response but this was much lower than that observed in the controls. These findings suggest the establishment of latent JEV infection in T lymphocytes.

Animals↗
PubMed1988

Immunological memory in latent Japanese encephalitis virus infection.

Long term B-cell memory to Japanese encephalitis virus (JEV) in latently infected mice was investigated by adoptive cell transfer. Both IgM and IgG memory were elicited by antigen challenge or cyclophosphamide induced reactivation of virus. A weak antigen-specific IgM response for a brief period and a strong IgG response were detected in Swiss albino mice exposed to secondary infection. A correlation between the secondary IgM antibody and protection against JEV challenge was observed in adoptive transfer experiments. This was abrogated by pretreatment of the serum with 2-mercaptoethanol. Similarly secondary immune splenic T-cells up to day 5 post-reactivation provided protection. These results suggest that a long term antigen-specific IgM and IgG memory was induced by JEV challenge in latently infected mice. Further, the role of IgM antibody and T-cells in the response of mice to secondary JEV infection has been shown.

Animals↗
PubMed1988

Immunopathological study of spleen during Japanese encephalitis virus infection in mice.

Following intraperitoneal inoculation, Japanese encephalitis virus replicated in peritoneal macrophages, appeared on day 3 in the splenic macrophages of the perifollicular region and later in cells of the periarteriolar lymphoid sheath (PALS) as shown by indirect immunofluorescence. Productive JEV infection was observed both in macrophages and T-cells. Morphological study of spleen during JEV infection revealed proliferative changes, with increased number of macrophages from day 3 p.i. in the perifollicular region followed by accumulation of polymorphonuclear leucocytes which reached a maximum on day 9 p.i. The T dependent areas were considerably enlarged by day 9 and gradually reduced in size by week 3. At later periods germinal centres appeared in the T independent area and were prominent by day 15. The cells containing virus antigen disappeared with the appearance of germinal centres, thus indicating the role of the latter also in virus clearance.

Animals↗
PubMed1987

Memory suppressor T cells in latent Japanese encephalitis virus infection.

The generation of secondary suppressor T (Ts) cells has been studied during latent Japanese encephalitis virus (JEV) infection of mice. The mice infected with JEV 27 weeks earlier, on challenge with the homologous virus, showed accelerated generation of secondary Ts cells; these appeared on Day 6, with peak activity on Day 8, and lasted for 27 days. The secondary Ts cells were Thy1.2+, Ly1-2+, antigen-specific, and acted in a dose-dependent manner. The secondary Ts cells could also be generated by reactivation of the JEV in latently infected mice. The findings thus show the presence of memory suppressor T cells in mice latently infected with JEV that can be stimulated to produce secondary Ts cells by exogenous or endogenous virus challenge. This phenomenon could help to persistence of the virus.

Animals↗
PubMed1987

Induction of secondary immune response by reactivated Japanese encephalitis virus in latently infected mice.

Development of secondary immune response has been studied following reactivation of latent Japanese encephalitis virus (JEV) infection in mice. The virus could be reactivated in 43% of the latently infected mice at 27 weeks p.i. by treatment with cyclophosphamide. The reactivated virus induced delayed-type hypersensitivity (DTH) and leucocyte migration inhibition (LMI) responses in mice, with peak activity on Day 5 post-reactivation (p.r.). The DTH persisted at low levels for long periods. Humoral immunity measured by haemagglutination-inhibiting antibody showed a four-fold rise in antibody titres. DTH was transferable by immune spleen cells for 5 days p.r. only. It is, therefore, concluded that JEV reactivation generates a quick and short-lived secondary immune response.

Animals↗