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Biomedical subjects

P Reddy

Publications and source records attributed to P Reddy.

At least 145 records · Page 8Linked to original sources
PubMed1984

Molecular analysis of the period locus in Drosophila melanogaster and identification of a transcript involved in biological rhythms.

We have isolated and analyzed DNA sequences encompassing the period (per) locus of Drosophila melanogaster. The location of this clock gene was delimited by the molecular mapping of chromosome aberrations at or very near the per locus. At least five RNAs are transcribed from this region. One of these transcripts, a 0.9 kb species, is strongly implicated in per's control of biological rhythms. Two independently isolated arrhythmic mutations at the per locus dramatically reduce the level of this transcript. Furthermore, the level of the 0.9 kb transcript is strongly modulated during a light/dark cycle. We discuss evidence, from previously reported genetic and phenotypic analysis of per's function, suggesting that this region may be complex and that several gene products from the per region, including this 0.9 kb transcript, may be involved in the different aspects of normal rhythmicity influenced by this clock gene.

Animals↗
PubMed1984

Flexible fiberoptic and rigid-rod lens endoscopy of the lower urinary tract: a prospective controlled comparison.

Cystourethroscopy was performed on 80 men by separate examiners with a rigid-rod lens instrument and a flexible fiberoptic choledochonephroscope. Findings with the flexible system were equivalent to or more accurate than those with the rigid endoscope in 94 per cent of the cases. With the flexible instrument the duration of the examination was unchanged, patient comfort was improved, the amount of irrigation fluid was reduced, and patient preparation and positioning were simpler and quicker.

Cystoscopes↗
PubMed1984

A logical approach to renal stone removal.

On the basis of experience with over 350 percutaneous stone extractions, a logical approach assuring a high success rate and minimizing complications is described. The importance of the position of the kidney in the body, the caliceal anatomy, the renal arterial anatomy, and the instrumentation used on puncture site selection are discussed. Strategies for removal of caliceal, pelvic, ureteral, and staghorn calculi, rationale, and treatment of complications are also described.

Humans↗
PubMed1983

Partial purification and characterization of heat stable protein phosphatase inhibitor-2 from rabbit reticulocytes.

Previous studies indicated that the species of type 1 and type 2 protein phosphatases (PP-1, PP-2) in rabbit reticulocytes are similar to those of rabbit skeletal muscle and rabbit liver. Reticulocyte PP-1 was found to be selectively inhibited by the heat stable protein phosphatase inhibitor-2 (I-2) from rabbit skeletal muscle. Of interest was the observation that muscle I-2 appeared to regulate protein synthesis in reticulocyte lysates by inhibiting an eIF-2 alpha phosphatase with type 1 properties. In this study we have characterized reticulocyte inhibitor-2 (I-2) and find that its properties are similar to those of skeletal muscle I-2. (i) Both I-2 species are stable to boiling and to acid treatment, and have similar chromatographic profiles on DEAE-cellulose and on Blue Sepharose CL-6B. (ii) The two I-2 species migrate electrophoretically as 26-28,000 dalton polypeptides in SDS-acrylamide gels. (iii) Both skeletal muscle I-2 and reticulocyte I-2 selectively inhibit isolated reticulocyte PP-1 and endogenous PP-1 in the lysate. (iv) Reticulocyte I-2 co-chromatographs with PP-1 on DEAE-cellulose, and over 90% of lysate I-2 can be isolated from this partially purified PP-1. (v) Both inhibitor-2 species are active in the unphosphorylated state, but upon addition to lysates, both are phosphorylated by endogenous cAMP-independent protein kinase(s). In addition a preliminary analysis using a polyclonal antibody against muscle inhibitor-1 confirmed biochemical analyses which indicate that lysates are deficient in inhibitor-1.

Animals↗
PubMed1983

The cardiovascular effects of high-dose butorphanol-nitrous oxide anaesthesia before and during operation.

The cardiovascular effects of high doses of butorphanol (0.3-0.45 mg . kg-1) plus 60 per cent N2O anaesthesia were measured at unconsciousness, following tracheal intubation, and immediately before and at one and ten minutes after surgical stimulation in 17 A.S.A. class I and II patients undergoing elective gastric or gall bladder surgery. Butorphanol and N2O produced unconsciousness with only small decreases in heart rate and cardiac output but did not result in sufficient analgesia to block or treat stimulation of the cardiovascular system secondary to tracheal intubation or surgical incision, even when supplemented with additional butorphanol to high cumulative dose levels (1.0 mg . kg-1). The data suggest that even high dose butorphanol - N2O anaesthesia requires supplementation with other anaesthetics or anaesthetic adjuvants to prevent cardiovascular stimulation during general abdominal surgery.

Adjuvants, Anesthesia↗
PubMed1983

Comparison of Doppler examination and retrograde spermatic venography in the diagnosis of varicocele.

The accuracy of the Doppler stethoscope is compared with that of retrograde spermatic venography in the diagnosis of varicocele in 39 subfertile men. In the 38 cases in which left-sided venography was successful, there was a good correlation between the radiographic and Doppler results in 33 cases (87%). The five failures were all false-negative results in patients without clinically diagnosed varicoceles. In the 33 cases in which right-sided venography was successful, there was a good correlation between the radiographic and Doppler results in 17 patients (52%). This low sensitivity on the right side appears to be a minor drawback, because right-sided reflux almost always occurs in conjunction with left-sided reflux, and therefore varicocele would be diagnosed in these patients despite the false-negative Doppler finding. Unlike venography, the Doppler study is noninvasive, inexpensive, and easy to perform. We conclude that it should be part of all studies of varicocele and infertility and that it may prove sufficiently accurate for use in controlled studies of the effectiveness of varicocelectomy and the role of subclinical varicocele in the pathogenesis of infertility.

Humans↗
PubMed1981

Hemodynamic effects of butorphanol-oxygen anesthesia in dogs.

The cardiovascular effects of two intravenous rates of butorphanol infusion (0.1 and 0.2 mg/kg/min) were measured in 32 dogs breathing oxygen and nitrous oxide in oxygen. Sixteen dogs were premedicated with atropine and the other 16 were unpremedicated. Of the dogs receiving the higher dose infusion rate, 25% moved with a tail-clamp stimulus whereas 75% moved with the lower doses. Butorphanol produced significant but similar cardiovascular depression with the two rates of infusion irrespective of the presence or absence of atropine medication. Addition of nitrous oxide resulted in further cardiac depression in all groups studied. The data suggest that butorphanol is not an attractive alternative to morphine or fentanyl as a narcotic anesthetic.

Animals↗
PubMed1980

Comparison of haemodynamic effects of anaesthetic doses of alphaprodine and sulfentanil in the dog.

The haemodynamic effects of equi-anaesthetic doses of alphaprodine and sulfentanil were evaluated in mongrel dogs ventilated mechanically. The effects of the addition of atropine were assessed for each drug, as were the effects of breathing nitrous oxide 60 per cent with oxygen and nitrogen 60 per cent with oxygen and the administration of naloxone. The results of this study demonstrate that anaesthetic doses of sulfentanil produce little change in cardiovascular dynamics in atropinized dogs and only small changes in dogs without atropine premedication, irrespective of the infusion rate. In contrast alphaprodine causes a significant cardiovascular depression irrespective of the presence or absence of atropine premedication. Naloxone reversed the anaesthetic effects in all dogs anaesthetized with alphaprodine but did not reverse the anaesthetic state in any dog given sulfentanil. Our data suggest that sulfentanil deserves evaluation as a narcotic anaesthetic in man.

Alphaprodine↗
PubMed1977

Modification and abolition of re-entry within the His-Purkinje system in man by diphenylhydantoin.

The phenomenon of macrore-entry (Re) within the His-Purkinje system (HPS) was consistently observed in 10 of 19 patients during retrograde refractory period studies. Effects of intravenous infusion of diphenylhydantoin (DPH) on Re were studied in these 10 patients 10 minutes after completion of infusion (mean plasma level equal to 17.0 microgram/ml). Diphenylhydantoin modified determinants of Re in seven patients (group I) and abolished Re in the remaining three patients (group II). In group I, DPH shortened the critical V1 V2 from 310.0 +/- 30.5 to 292.9 +/- 25.6 msec (P less than 0.025) and critical V2 H2 intervals for Re from 201.4 +/- 18.4 to 185.0 +/- 13.8 msec (P greater than 0.05). In group II, DPH abolished Re in two of three patients by precluding attainment of critical V2 H2 intervals whereas Re was abolished in the remaining one patient despite attainment of critical V2 H2 intervals (vs control). For both groups, DPH significantly shortened functional and effective refractory periods of the HPS (P less than 0.001 and less than 0.01, respectively) without significantly affecting the effective refractory period of the ventricular muscle. Diphenylhydantoin either completely abolished or significantly shortened the retrograde gap zones in the HPS. It is concluded that diphenylhydantoin significantly shortens His-Purkinje system refractoriness, abolishing Re in the patients with higher degree of improvement in refractoriness.

Adult↗