Biomedical subjects

K V N Rao

Publications and source records attributed to K V N Rao.

4 recordsLinked to original sources

PubMed2006

Chemoprevention of rat prostate carcinogenesis by dietary 16alpha-fluoro-5-androsten-17-one (fluasterone), a minimally androgenic analog of dehydroepiandrosterone.

Dehydroepiandrosterone (DHEA) is a potent inhibitor of prostate carcinogenesis in rats. However, concerns related to the possible androgenicity of DHEA may preclude its use for chemoprevention of human prostate cancer. Studies were performed to compare the androgenicity of DHEA and a fluorinated DHEA analog, 16alpha-fluoro-5-androsten-17-one (fluasterone), and to determine the chemopreventive activity of fluasterone in the rat prostate. Comparisons of accessory sex gland weight and histology in gonadectomized male rats demonstrated that fluasterone is less androgenic than is DHEA. Fluasterone conferred significant protection against prostate carcinogenesis induced in Wistar-Unilever rats by a sequential regimen of N-methyl-N-nitrosourea+testosterone. Chronic administration of fluasterone at levels of 2000 and 1000 mg/kg diet reduced the incidence of adenocarcinoma in the dorsolateral/anterior prostate from 64% in dietary controls to 28 and 31%, respectively. Other than a dose-related suppression of body weight gain, chronic exposure to fluasterone induced no clinical evidence of toxicity; suppression of body weight gain may be either a pharmacological effect or a minimally toxic effect of the compound. These data demonstrate that a minimally androgenic analog of DHEA protects against prostate carcinogenesis induced in rats by a chemical carcinogen + androgen. The reduced androgenicity of fluasterone may obviate toxicities associated with the androgenicity of the parent compound. On this basis, fluasterone merits consideration for evaluation in clinical trials for prostate cancer prevention. The chemopreventive activity of a non-androgenic DHEA analog suggests that at least a portion of the chemopreventive activity of DHEA in the rat prostate is unrelated to hormonal effects.

Animals↗

PubMed2003

Improved sensitivity for solid-support invasive cleavage reactions with flow cytometry analysis.

A new configuration of the solid-support invasive cleavage reaction provides a small reaction-volume format for high-sensitivity discrimination of nucleic acid targets with single nucleotide differences. With target concentrations as low as 2 amol/assay, the solid-support invasive cleavage reaction clearly distinguishes single base mutations. Two oligonucleotides tethered to the solid support hybridize to the target nucleic acid, forming a tripartite substrate that can be recognized and cleaved by Cleavase, a structure-specific 5'-nuclease. Each cleavage event yields fluorescence signal on the surface. When microspheres serve as the solid-support surface, analysis by fluorometer imparts real-time information about change in the reaction signal over time. Flow cytometry provides an alternative detection technology that collects endpoint information about the reaction signal on individual microspheres. A reaction volume of 10 microL with as few as 3000 microspheres is sufficient to distinguish single nucleotide differences at target concentrations less than 200 fM. This sensitivity level is within the range required for analysis of SNPs in genomic DNA. In addition, the flow cytometry format has multiplexing potential, making the microsphere-based invasive cleavage assay attractive for high-throughput genomic applications.

Apolipoproteins E↗

PubMed2002

Molecular characterization of a calcium binding translationally controlled tumor protein homologue from the filarial parasites Brugia malayi and Wuchereria bancrofti.

We have cloned homologues of the mammalian translationally controlled tumor protein (TCTP) from the human filarial parasites Wuchereria bancrofti and Brugia malayi. TCTP genes from B. malayi and W. bancrofti were expressed in a T7 promoter vector as histidine tagged fusion proteins. Both the recombinant B. malayi TCTP (rBm-TCTP) and recombinant W. bancrofti TCTP (rWb-TCTP) have a molecular mass of approximately 28 kDa with the histidine tag. Sequence analyses showed that there is a 98% similarity between the two filarial TCTPs at amino acid levels and are immunologically cross-reactive. Analysis of soluble proteins from various lifecycle stages of B. malayi suggested that the expression of Bm-TCTP might be differentially regulated and occurs in multimeric form. Recombinant TCTP were found to form multimers in solution under non-reducing conditions. The tendency for filarial TCTPs to become multimers was predicted by the presence of the Lupas coiled coil structure in their sequence. Despite the absence of a signal sequence, Bm-TCTP is present abundantly in the excretory/secretions (ES) of microfilariae. Characterization studies showed that both Bm- and Wb-TCTPs are calcium-binding proteins and have histamine-releasing function in vitro. When injected intraperitoneally both the filarial TCTPs induced inflammatory infiltration of eosinophils into the peritoneal cavity of mice suggesting that the filarial TCTPs may have a role in the allergic inflammatory responses associated with filarial infections.

Amino Acid Sequence↗

PubMed2002

Suppression of cutaneous inflammation by intradermal gene delivery.

Biological effects of in vivo transfection of a potential anti-inflammatory gene, designated Sm16, cloned from the human parasite Schistosoma mansoni were analyzed in these studies. A single intradermal injection of a full-length cDNA of Sm16 resulted in the expression of Sm16 in the epidermis, dermis, skin migratory cells and skin-draining lymph nodes of mice for up to 7 days. Subsequently the anti-inflammatory effect of this gene expression was evaluated by inducing an inflammatory response in the skin of mice. These studies showed that Sm16 gene delivery resulted in a significant suppression of cutaneous inflammation as shown by a reduction in cutaneous edema, decrease in neutrophil infiltration, suppression of pro-inflammatory cytokine expression and down-regulation of ICAM-1 expression in the skin inflammatory site. Cells collected from the skin-draining lymph nodes showed reduced proliferation to mitogen. Multiple intradermal injection of Sm16 cDNA failed to induce any antibody response in mice for up to 8 weeks after initial injection. These findings suggest a potential for developing Sm16 gene delivery as a therapeutic agent for treating inflammatory skin disorders.

Animals↗