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Biomedical subjects

G Prasad

Publications and source records attributed to G Prasad.

At least 19 recordsLinked to original sources

Experimental observations of transverse shear waves in strongly coupled dusty plasmas.

We report experimental observations of transverse shear waves in a three-dimensional dusty plasma that is in the strongly coupled fluid regime. These spontaneous oscillations occur when the ambient neutral pressure is reduced below a threshold value and the measured dispersion characteristics of these waves are found to be in good agreement with predictions of a viscoelastic theory of dusty plasmas.

Journal Article↗

Antisense anticancer oligonucleotide therapeutics.

Recent progress made in molecular biology, biotechnology, and genetics, especially in identifying, cloning, sequencing and characterization of normal and pathogenic genes, has led to the development of genetic therapy. Major efforts in the field can be summarized in two general approaches: gene therapy and antisense therapy. The second is to deliver to the target cells antisense molecules that target to mRNA with which they can hybridize and specifically inhibit the expression of pathogenic genes. Antisense oligonucleotides offer the possibility of specific, rational, genetic-based therapeutics. With encouraging results from preclinical and clinical studies of antisense oligonucleotides in the past decade, significant progress has been made in developing antisense therapy, with the first antisense drug now being approved for clinical use. In this article, we will discuss approaches to developing these drugs from preclinical to clinical settings. Of particular interest for the area of human cancer therapy, several cancer targets, including bcl-2, BCR-ABL, C-raf-1, Ha-ras, c-myc, PKC, PKA, p53 and MDM2, are reviewed as examples to illustrate the progress in this field and emphasize the importance of target selection and advanced antisense chemistry in the development of antisense therapy.

Antineoplastic Agents↗

Comparative evaluation of sensitivity of RNA-polyacrylamide gel electrophoresis and dot immunobinding assay for detection of bluetongue virus in cell culture.

Bluetongue virus serotype 1 (Avikanagar isolate) was grown in BHK-21 cell line and titrated. The titre of the virus in BHK-21 cell line was 10(6) TCID50/ml. RNA-polyacrylamide gel electrophoresis (RNA-PAGE) and dot immunobinding assay (DIA) were performed on 10-fold serial dilutions of the sonicated cell culture material. The results indicated that the minimum limit of detection of the virus by RNA-PAGE and DIA was 10(5) TCID50/ml.

Animals↗

RT-PCR and its detection limit for cell culture grown bluetongue virus 1 using NS1 gene group specific primers.

RT-PCR was standardised for the detection of bluetongue viral RNA using highly expressed non structural protein 1 gene as the target gene with specific primers targeted to 274 bp of 5' end of NS1 gene. PCR product was consistently obtained in 30 PCR cycles. Further, detection limit of RT-PCR was estimated using serial 10 fold dilutions of BHK 21 cells grown BTV 1. The study suggested that RT-PCR can be used for detection of BTV in Indian conditions with the sensitivity limit of 10 infectious particles of the virus. The study suggested that this technique may be used as a tool for sensitive detection of BTV in carrier/reservoir animals, insect vectors and certification of animals and their germ- plasm for export and import purposes.

Animals↗

Cyclic hydroxamic acid inhibitors of prostate cancer cell growth: selectivity and structure activity relationships.

BACKGROUND: Clinical symptoms of prostatitis, prostatodynia, and benign prostatic hyperplasia are relieved by the pollen extract cernilton, and the water-soluble fraction of this extract selectively inhibits growth of some prostate cancer cells. A cyclic hydroxamic acid, DIBOA, has been isolated from this extract and mimics its cell growth-inhibitory properties, but the specificity of DIBOA for inhibition of prostate cell growth has not been reported. METHODS: The in vitro growth inhibitory effects of DIBOA and nine structurally related compounds on DU-145 prostate cancer cells, MCF-7 breast cancer cells, and COS-7 monkey kidney cells were determined by treatment of the cells with various concentrations of the compounds for 2-6 days. RESULTS: The compounds exhibited a wide range of potencies, but none of them exhibited selective inhibition of DU-145 cell growth. MCF-7 cells were more sensitive to DIBOA than either DU-145 cells or COS-7 cells. 3,4-dihydroquinoline-2(1H)-one, compound (4), and 1-hydroxy-6-chloro-3,4-dihydroquinolin-2(1H)-one, compound (7), selectively inhibited MCF-7 cell growth at a concentration of 10 micrograms/ml. 1-hydroxy-3,4-dihydroquinolin-2(1H)-one, compound (3), and compound 7 were the most potent inhibitors of DU-145 cell growth. Treatment of DU-145 cells with 3 (100 micrograms/ml) substantially decreased the number of viable cells within 2 days, and no viable cells remained in the culture by day 4. CONCLUSIONS: It is unlikely that DIBOA, compound (1), is responsible for the selective growth inhibition of prostate cancer cells by the water-soluble fraction of the pollen extract cernilton. Cell morphology results indicate that the growth-inhibitory effects of DIBOA and structurally related agents on DU-145 cells are due to their ability to cause cell death.

Benzoxazines↗

Evaluation of recombinant bluetongue virus antigens, using dot immunobinding assay with serum from sheep and cattle.

OBJECTIVE: To evaluate 2 genetically engineered group-specific antigens: baculovirus- and yeast-expressed VP7 and the conventionally produced group-specific antigen of bluetongue virus (BTV), using dot immunobinding assay (DIA). SAMPLE POPULATION AND PROCEDURE: A total of 260 serum samples of sheep and cattle from various livestock farms in different Indian states (eg, Haryana, Himachal Pradesh, Jammu and Kashmir, Punjab, and Rajasthan) were tested for the presence of BTV antibodies by DIA. RESULTS: Of 260 sera tested, 92 (35%) were positive for BTV antibodies using the baculovirus-expressed antigen, 96 (37%) were positive using the yeast-expressed antigen, and 103 (40%) were positive by use of conventionally produced antigen. CONCLUSION AND CLINICAL RELEVANCE: The overall agreement for all the 3 antigens was 92%, indicating that the recombinant group-specific proteins can be used for serodiagnosis of BTV, using DIA.

Animals↗

In vitro susceptibility of goat mononuclear cells to bluetongue virus.

Goat peripheral blood mononuclear cells were cultured and their susceptibility to bluetongue virus (BTV) serotype 1 was tested. A small number of adherent and non-adherent cells were found positive for BTV antigens by immunoperoxidase and immunofluorescence tests. Both adherent and non-adherent cells supported limited level of viral replication as evidenced by low titre in the biological assay, thus indicating their susceptibility.

Animals↗

Relative superiority of c-ELISA for detection of bluetongue virus antibodies.

Anti-VP7 bluetongue virus (BTV) antibodies were detected in sera of ruminant livestock using competitive enzyme linked immunosorbent assay (c-ELISA). The per cent positivity for BTV antibodies recorded in sheep was 34.61% in Haryana, 7.14% in Himachal Pradesh and 28.88% in Punjab. Goat showed 64% positivity in Haryana, 67.34% in Himachal Pradesh and 88.33% in Rajasthan whereas cattle showed 67.44% positivity in Haryana, 52.17% in Punjab and 59.15% in Rajasthan for BTV antibodies. The percent positivity recorded for buffalo was 54.05% in Punjab. A comparison of c-ELISA with dot-ELISA for a total of 181 serum samples of sheep and cattle was also done. The performance of c-ELISA relative to dot-ELISA was found to have a sensitivity of 84.61% and specificity of 89.32%.

Animals↗

Isolation of bluetongue virus from sheep in Rajasthan State, India.

A cytopathic agent was isolated in a baby hamster kidney (BHK)-21 cell-line from blood samples of cross-bred sheep showing typical bluetongue symptoms at Avikanagar in Rajasthan State, India. The cytopathic agent was identified as a bluetongue virus (BTV) by immunofluorescence, the immunoperoxidase test and electron microscopy of BHK-21 cells infected with the new isolate. The new isolate was typed as BTV serotype 1.

Animals↗

Bluetongue virus infection in India: a review.

The history and epizootiology of bluetongue (BT) in India are reviewed. BT has become endemic in India. The first outbreak of BT in sheep and goats in the country was recorded in 1964 in Maharashtra State. Since then, several outbreaks of BT have been reported in sheep. Exotic sheep are more susceptible than indigenous and cross-bred sheep. A serological survey has indicated the presence of bluetongue virus (BTV) antibodies in cattle and buffalo in several states in India. However, clinical BT has not been observed in cattle or buffalo to date. Of the 24 known serotypes of BTV, 18 have been reported in India. Although BTV has been isolated from Culicoides midges, the particular species responsible for transmission has not yet been identified.

Animals↗

Characterization of a continuous lymphocyte cell line derived from BALB/c mice inoculated with a recombinant Moloney murine leukemia virus-TB.

Neonatal BALB/c mice were inoculated (ip) with a recombinant Moloney murine leukemia virus-TB. Majority of the inoculated mice developed lymphoma within 5-7 months post infection. The cells from splenic lymphomas were cultured and 3 continuous cell lines (GP1, GP2 and GP3) developed. GP1 was single cell cloned and characterized. Based on Thy 1.2 (98.4%) phenotypic marker, the cell line was categorized as T cell line. The percent positivity for different cell surface markers on analysis with FACS was 98.4, 4.8, 5.5, 2.2, 1.8, 1.2 and 9.5 for Thy 1.2, mu, L3T4, Lyt2, Ia, IL2R and PNA receptor, respectively. A total of 16.5% GP1 cells was also positive for Moloney murine leukemia virus envelope protein (gp 70). Incomplete retrovirus like particles were demonstrated in the cytoplasm of GP1 cells by electron microscopy. The cell line on inoculation(ip) in neonatal BALB/c mice produced lymphomic lesions in almost all the vital organs of the mice.

Animals↗

Pathogenesis of age dependent paralysis by a temperature sensitive mutant (tsl) of Moloney murine leukemia virus-TB.

The tsl mutant of Moloney murine leukemia virus-TB produces neurological disease leading to fatal hind limb paralysis when inoculated in newborn BALB/c mice. The present study was under taken to assess the role of T and B lymphocytes in age dependent resistance to tsl induced paralysis in BALB/c mice. The adoptive transfer of non-immune splenic unseparated lymphoid cells, T cells and B cells and tsl immune B cells and T cells to newborn BALB/c mice infected with tsl did not prevent the development of paralysis. However, adoptive transfer of immune splenic unseparated lymphoid cells and immune T cells delayed the onset of paralysis by 5 to 10 days as compared to the mice which did not receive the immune lymphocytes. Athymic BALB/c nude mice inoculated with tsl at days 1 and 10 after birth failed to develop the paralytic disease. Transfer of tsl neutralising antibody also delayed the onset of paralysis. Mice (10 days old) treated with cyclophosphamide, cyclosporine A, cortisone acetate and anti-T cell serum when inoculated with tsl also did not develop neurological disease. The results suggest that age related resistance to neurological disease may not be associated with B cell mediated immunity.

Age Factors↗

Anencephaly.

Explore the source record for details and available documents.

Adolescent↗

Dot immunobinding assay for the detection of bluetongue virus antibodies in sheep experimentally inoculated with bluetongue virus type 1.

Dot immunobinding assay (DIA) was evaluated for the detection of bluetongue virus (BTV) antibodies in sheep experimentally inoculated with BTV 1. Serum samples collected on 14, 21, 28, 43 and 60 day post infection (dpi) were positive for precipitating antibodies by the agar gel precipitation test (AGPT) while antibodies could be detected as early as 7 dpi by DIA and ELISA. Virus neutralizing antibodies were detected first at 14 dpi. The sensitivity of the four tests was compared on the same serum samples collected at different intervals. The results indicated that DIA was more sensitive than AGPT and the serum neutralization test and as sensitive as ELISA. Thus due to sensitivity simplicity and economy, DIA could replace AGPT for diagnosis and serological survey for BTV infection in animals.

Animals↗

Characterisation of cell-wall-derived polypeptide antigens from different species of Mycobacterium.

Cell walls from different species of Mycobacterium were purified on a sucrose step gradient. The components derived from these preparations were characterised by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, followed by staining or by Western blotting. Surface-exposed polypeptide molecules were also identified by biotinylation. Many protein and glycoprotein molecules were identified in the cell walls. Some of these molecules were immunogenic in man and experimental animals and showed wide variability from species to species. The data suggest that these molecules could be of significance in the diagnosis and pathophysiology of mycobacterial diseases.

Antigens, Bacterial↗

Structure-activity relationships for the inhibition of DNA polymerase alpha by aphidicolin derivatives.

Aphidicolin and 17 derivatives that have been structurally modified in the A- and D-rings were assessed for their ability to inhibit DNA polymerase alpha. No derivative surpassed the activity of aphidicolin; derivatives with structural alterations in the A-ring exhibited significantly greater loss of activity relative to derivatives with structural alterations in the D-ring. The conclusions of these studies indicate a critical role for the C-18 function in the interaction of aphidicolin with polymerase alpha. Molecular modelling studies could not identify structural features of the aphidicolin-dCTP "overlap" that is unique to dCTP, relative to the remaining dNTPs, and that is consistent with the extant structure-activity data.

Aphidicolin↗

The role of the thymus in the pathogenesis of hind-limb paralysis induced by ts1, a mutant of Moloney murine leukemia virus-TB.

Newborn homozygous BALB/c nude (nu/nu) mice, their heterozygous (+/nu) littermates, and normal BALB/c (+/+) mice were infected with ts1, a paralytogenic mutant of Moloney murine leukemia virus-TB (MoMuLV-TB). Our results indicate that while infection of +/nu and +/+ mice with ts1 results in severe pathological changes in the central nervous system (CNS) and paralysis, infection of nu/nu mice results in only mild to moderate pathology within the CNS and no paralysis. On the other hand, 50% of nude mice reconstituted with T cells when infected with ts1 developed paralysis and showed more pronounced degeneration of nervous tissue than nude mice infected with ts1 alone. These observations strongly suggest that the thymus, the functional T lymphocytes, or both play an important role in the ts1-induced neurologic disorders in infected mice.

Animals↗