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Biomedical subjects

M M Rao

Publications and source records attributed to M M Rao.

At least 37 records · Page 2Linked to original sources
PubMed1996

Quantification of phenylbutazone in equine sera by use of high-performance liquid chromatography with a nonevaporative extraction technique.

OBJECTIVE: To develop a sensitive, rugged high-performance liquid chromatography (HPLC) method for the measurement of phenylbutazone (PBZ) in equine sera, using a rapid, nonevaporative extraction technique. SAMPLE POPULATION: Sera from 5 nonexercising adult horses. PROCEDURE: After addition of sodium chloride and acetonitrile to serum samples, reverse-phase HPLC analysis for PBZ and oxyphenbutazone (OXY) was performed directly on extracts, using diode array UV spectrophotometric detection. Probenecid was used as an internal standard. Data were evaluated by standard means of statistical analysis. RESULTS: Recoveries of PBZ, OXY, and probenecid from spiked samples were acceptable (ie, > or = 80%) and within run retention times were reproducible. Chromatograms were free of interfering substances, and linearity of calibration curves was observed throughout operational ranges. Coefficients of variation at each fortified PBZ concentration were in the 5 to 10% range. The method was applicable to analysis of PBZ and OXY in serum extracts from horses dosed with PBZ (4.4 mg/kg of body weight, IV) in a controlled environment. Track samples analyzed by use of this method and a conventional liquid/liquid extraction method gave comparable results (mean deviation, 1.6%) for PBZ concentrations. CONCLUSION: The HPLC protocol described is suitable for measuring PBZ and OXY in equine sera to regulate PBZ administration in horses involved in pari-mutuel racing.

Animals↗
PubMed1989

Screening and confirmation of drugs in horse urine by using a simple column extraction procedure.

A simple and reproducible column (Clean Screen-DAU, copolymeric bonded-phase silica column) extraction procedure has been described for the screening and confirmation of drugs in horse urine. The recovery of drugs by the column extraction was better than or comparable to the recovery by the liquid-liquid extraction, which is commonly used in the equine analytical laboratories. The column extraction provided broad coverage of drugs, separated extracts into three fractions (acidic/neutral, steroids, basic), produced a cleaner extract, and eliminated the need for special liquid-liquid extraction procedures for different drugs. The column extract was cleaner and did not contain impurities, whereas, the liquid-liquid extract was relatively impure and the extract required further thin-layer chromatographic cleanup. The column extraction procedure was used to confirm the presence of several potent drugs, such as fentanyl, etorphine, and mazindol.

Animals↗
PubMed1987

Expression of the Kirsten ras viral and human proteins in Escherichia coli.

The expression vectors pINIII-A and pINIII (lpp p5) were used to construct plasmids which direct the synthesis in Escherichia coli of the Kirsten ras viral (v-Ki-ras) and human cellular (c-Ki-ras) oncogene products as fusion proteins containing 9 and 10 extra amino acids, respectively, at their N termini. Authenticity of the bacterially produced proteins was determined by immunoprecipitation and immunoblot analyses with ras-specific monoclonal antibodies. After induction with isopropyl-beta-D-thiogalactopyranoside, the viral protein represented approximately 20% of the total cellular protein. The majority of the protein was found in the postsonication low-speed centrifugation pellet. The synthesized viral protein was active in GTP binding, as judged by autophosphorylation and photoaffinity labeling assays.

DNA Restriction Enzymes↗
PubMed1984

The effect of purine and pyrimidine bases on splenic plaque-forming cells and cellular immunity.

The effects of a variety of purine and pyrimidine bases on splenic plaque-forming cells and cellular immunity in mice are presented. The antibody-forming plaque cells were measured in spleens of female C57/B1 mice by the Jerne plaque method using sheep red blood cells as the antigen. Bases were given on days 0 and 1 at doses varying from 2 to 200 mumoles per mouse and the antigen was given on day 0; the antibody response was measured on day 4. Cell-mediated immunity was measured by the survival of 1 cm2 skin allografts transplanted across an H-2 histocompatibility barrier in female mice from C57/B1 donors to Balb/c recipients. For the plaque assay, adenine given at 25 and 50 mumoles/mouse and adenosine at 100 mumoles/mouse, resulted in significant 7 to 14-fold immunosuppression. Adenosine at 25 and 50 mumoles/mouse and guanosine and hypoxanthine at 100 mumoles/mouse resulted in an approximate 2-fold immunoenhancement. 2'-Deoxyadenosine, inosine, guanine, 2'-deoxyguanosine and the pyrimidines cytosine, cytidine, 2'-deoxycytidine, 2'-deoxythymidine and uridine all given at 100 mumoles/mouse and orotic acid given at 25 mumoles/mouse had no significant effects on the plaque response; orotic acid at a dose of 50 mumoles/mouse was lethally toxic to mice. In the primary immune response adenine was immunosuppressive at day 4, but significantly immunoenhancing at days 7 and 11. In the secondary response, adenine was immunosuppressive up to day 3 of the IgG and IgM responses; however, immunoenhancement occurred at day 4 (IgM) and day 5 (IgG). In the cell-mediated immune response, adenine at doses of 25 and 50 mumoles/mouse resulted in a significant 40% increase in the survival of skin allografts across an H-2 histocompatibility barrier.

Animals↗
PubMed1984

The spectral domain of multivariate harmonizable processes.

The spectral or frequency domain of a multivariate weakly harmonizable process is a vector space of vector functions that are integrable relative to a positive definite matrix bimeasure. It has a norm derived from a Gramian inner product. The completeness property of this space, which is needed for many applications, has been open for some years. An affirmative solution and an application to optimal least-squares estimation of a weakly harmonizable signal are presented here.

Journal Article↗
PubMed1984

A sheep preparation for studying interactions between blood flow and drug disposition. I: Physiological profile.

A sheep preparation has been developed which allows repeated measurements of regional blood flow, oxygen consumption and drug disposition in awake, unrestrained animals. This allows systematic studies of both acute changes, such as haemodynamic disturbances, and of chronic changes, such as enzyme induction, to be carried out. Good agreement was shown between the values for cardiac output and regional blood flow obtained by the Fick and indicator dilution methods, and those obtained by others using microspheres. Significant day-to-day fluctuations in haemodynamic indices were shown to occur; assumptions that hepatic or renal blood flows are constant fractions of cardiac output, or that renal or hepatic flow indicator extraction ratios remain unchanged from day-to-day, will lead to significant errors. Thus, control measurements for each experiment are necessary. It is proposed that physiological models for studying drug disposition based on data from awake, unrestrained animals may provide insight into some mechanisms of changes in drug disposition that cannot be obtained using the traditional compartmental method.

Animals↗
PubMed1983

Intrarenal abscess in a transplant organ.

We report the first case of an intrarenal abscess in a transplant organ. Diagnosis was made by ultrasonography and excretory urography, and was confirmed by percutaneous aspiration under ultrasonographic guidance. Surgical drainage and systemic antibiotic therapy resulted in complete resolution of the lesion and no change in renal function.

Abscess↗
PubMed1981

Representation of weakly harmonizable processes.

Weakly harmonizable processes are represented by a family of positive definite contractive linear operators in a Hilbert space. This generalizes the known result on weakly stationary processes involving a unitary family. A characterization of the vector Fourier integral of a measure on R --> [unk], a reflexive space, is given, and this yields another characterization of weakly harmonizable processes when [unk] is a Hilbert space. Also these processes are shown to have associated spectra, yielding a positive solution to a problem of Rozanov.

Journal Article↗
PubMed1979

The effect of prostatectomy on urodynamic parameters.

Sixty per cent of men subjected to prostatectomy had unstable bladders. It was found that this was related to the presence of either an indwelling catheter or obstruction, but had little influence on the result of prostatectomy. The functional urethral pressure profile length did not correlate with the size of the prostate gland. Shortening of the prostatic plateau was always found, but the extent to which the plateau was reduced did not correlate with urine flow rates.

Adult↗
PubMed1977

Cytogenetic studies in primary infertility.

Chromosome studies were conducted on 117 men with primary infertility (54 with oligospermia and 63 with azoospermia) and 25 fertile volunteers who acted as controls. No chromosomal abnormalities were observed except for nine cases of Klinefelter's syndrome. From this study, it is apparent that chromosomal abnormalities other than Klinefelter's syndrome are not etiologic factors in the infertility of oligo- or azoospermic men.

Chromosome Aberrations↗