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Biomedical subjects

P Narayan

Publications and source records attributed to P Narayan.

191 records · Page 11Linked to original sources
PubMed1981

Transvenous embolization of internal spermatic veins: nonoperative approach to treatment of varicocele.

Eleven men, shown on routine spermatic venography to have bilateral varicocele, underwent transjugular bilateral embolization of the internal spermatic veins with stainless steel coils or Ivalon plugs. Embolization of the left spermatic vein was successful in 9; in the other 2 it was not attempted because of aberrant drainage of the vein. Embolization of right spermatic vein was successful in 8 patients. There were three complications, none of which was serious. These preliminary results suggest that both internal spermatic veins can be occluded consistently by the transjugular approach. However, it has not yet been established that fertility is improved by detecting and correcting varicocele on the right side.

Embolization, Therapeutic↗
PubMed1981

Varicocele and male subfertility.

Unilateral and bilateral subclinical varicocele was found by internal spermatic venography in 10 of 30 men with stress-pattern semen and normal endocrine profiles. Seven of the 10 had no clinical evidence of varicocele. Right-sided varicocele may be almost as common as varicocele on the left and may be responsible for much of the bilateral effect of clinical left-sided varicocele. Transjugular venography has a low morbidity rate and can be used to clarify the relation between subclinical varicocele and infertility. The technique also permits nonsurgical treatment of varicocele.

Adult↗
PubMed1981

Embolization of the spermatic vein for treatment of infertility: a new approach.

A new transjugular technique for spermatic venography and nonsurgical transcatheter occlusion of incompetent spermatic veins is described. With this technique, the left spermatic vein was easily catheterized in 28 of 30 patients examined, and in 21 patients the vein could be occluded. Right spermatic vein catheterization was attempted in 25 patients. Right-sided spermatic vein occlusion was successful in 17 of 24 patients. The vein could not be selectively entered only twice. Bilateral incompetence of the spermatic veins in men with primary sterility is the rule rather than the exception. Valvular incompetence does not necessarily produce a clinically detectable varicocele. Bilateral venography is indicated in all men with abnormal spermiograms.

Adult↗
PubMed1977

Slow persistent infection caused by visna virus: role of host restriction.

Proviral DNA has been demonstrated by in situ hybridization in foci of cells of a lamb infected with the RNA slow virus visna. A few of these cells also contain the major virion structural antigen p30. This restriction in virus gene expression in the infected animal provides a mechanism for persistence of virus in this chronic infection.

Animals↗
PubMedDate not supplied

Phosphorus metabolite characterization of human prostatic adenocarcinoma in a nude mouse model by 31P magnetic resonance spectroscopy and high pressure liquid chromatography.

A series of experiments were conducted to identify and quantify the phosphorus metabolites of DU 145 xenografts (a human prostatic adenocarcinoma cell line grown in nude mice) using 31P MRS and HPLC. The 31P spectral characteristics of DU 145 xenografts were compared to perfused DU 145 cells and to in situ human prostatic adenocarcinomas. These studies demonstrated that both DU 145 xenografts and perfused DU 145 cells exhibited reduced levels of phosphocreatine relative to spectra of in situ human prostatic adenocarcinomas. Elevated levels of phosphomonesters (PMEs) were observed in 31P spectra of both DU 145 xenografts and in situ human prostatic adenocarcinomas. The major components of the PME resonance of DU 145 xenografts were identified as phosphocholine and phosphoethanolamine. High levels of diphosphodiesters (DPDEs) were consistently observed for both DU 145 xenografts and perfused DU 145 cells, but were absent in 31P spectra in in situ primary human adenocarcinomas. In agreement with spectroscopic results, high pressure liquid chromatographic analyses of human tissue removed at surgery contained insignificant amounts of DPDEs while DU 145 xenografts had high levels of DPDEs consisting mainly of uridine-5'-diphospho-N-acetylgalactosamine (22.4 nmol/mg protein) and uridine-5'-diphospho-N-acetylglucosamine (7.4 nmol/mg protein).

Adenocarcinoma↗
PubMedDate not supplied

A comparison of two phase III multicenter, placebo-controlled studies of tamsulosin in BPH.

In two large, multicenter, double-blind, parallel, US phase III clinical trials, men with benign prostatic hyperplasia were randomized to receive tamsulosin, either 0.4 or 0.8 mg daily, or placebo for 13 weeks. Efficacy was determined by changes from baseline in American Urological Association (AUA) symptom scores and peak urinary flow and by percentages of responders with clinically meaningful (> 25%) AUA score improvement and at least 30% increase in peak urinary flow. Secondary efficacy parameters were AUA and Boyarsky irritative, obstructive, and individual scores; investigators' global assessment; and a total quality-of-life evaluation. Also analyzed were laboratory test results and adverse events, including orthostatic and antihypertensive effects. A trend toward statistically significant improvement occurred in all primary and secondary efficacy endpoints at both dosages versus placebo, except for peak urinary flow rate at endpoint in one trial with 0.4 mg of tamsulosin (P = .064). Urinary flow rates increased within hours after first tamsulosin dose. No clinically or statistically meaningful sitting blood pressure or symptomatic orthostatic changes were seen, and no physical findings or alterations in laboratory or electrocardiographic results were attributable to treatment. Tamsulosin 0.4 and 0.8 mg daily had a rapid onset of action and was effective and well tolerated, with minimal differences observed between dosage groups. The incidence of side effects was similar to that with placebo, and efficacy was sustained with 0.4 mg daily.

Double-Blind Method↗
PubMedDate not supplied

Delta-opioid receptor antagonist inhibits immunomodulation by Met-enkephalin analogs.

The methionine-enkephalin (Met-enkephalin, Tyr-Gly- Gly-Phe-Met) analogs Tyr-D-Ala-Gly-MePhe-Met NHC(3)H(7)-iso (1) and Tyr-D-Ala-Gly-MePhe-Gly-NHC(3)H(7)-iso (2) have been shown to enhance human T cell proliferation in in vitro treatment. Their immunomodulatory activities were completely blocked by naloxone, an opioid antagonist. Now we demonstrate that a selective delta-opioid receptor antagonist, ICI-174,864, completely blocks enhancement of T cell proliferation by analogs (1) and (2). The T cell-stimulatory effect was only partially inhibited by the mu-receptor-selective antagonist, beta-funaltrexamine hydrochloride. The kappa-opioid receptor antagonist, nor-binaltorphimine dihydrochloride, showed no effect on T cell-proliferation stimulated by analogs (1) and (2). These observations suggest that analogs (1) and (2) of Met-enkephalin stimulate T cell proliferation predominantly via delta-opioid receptor present on T cells.

Adjuvants, Immunologic↗
PubMedDate not supplied

Acute allograft failure in thoracic organ transplantation.

Thoracic organ transplantation is an effective form of treatment for end-stage heart and lung disease. Despite major advances in the field, transplant patients remain at risk for acute allograft dysfunction, a major cause of early and late mortality. The most common causes of allograft failure include primary graft failure secondary to inadequate heart and lung preservation during cold storage, cellular rejection, and various donor-recipient-related factors. During cold storage and early reperfusion, heart and lung allografts are vulnerable to intracellular calcium overload, acidosis, cell swelling, injury mediated by reactive oxygen species, and the inflammatory response. Brain death itself is associated with a reduction in myocardial contractility, and recipient-related factors such as preexisting pulmonary hypertension can lead to acute right heart failure and the pulmonary reimplantation response. The development of new methods to prevent or treat these various causes of acute graft failure could lead to a marked improvement in short- and long-term survival of patients undergoing thoracic organ transplantation.

Acute Disease↗