Biomedical subjects

R C Cochran

Publications and source records attributed to R C Cochran.

83 records · Page 5Linked to original sources

PubMed1981

Serum levels of follicle stimulating hormone, luteinizing hormone, prolactin, testosterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 alpha-androstane-3 beta, 17 beta-diol, and 17 beta-estradiol from male beagles with spontaneous or induced benign prostatic hyperplasia.

The serum concentration of testosterone (T) 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol), 5 alpha-androstane-3 beta , 17 beta-diol (3 beta-diol), luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin in young (less than 40 months) beagles with spontaneous benign prostatic hyperplasia (BPH) were not significantly (P greater than 0.25) different from serum hormone levels of age matched controls, or old (greater than 60 months) beagles with BPH. However, the serum hormone levels of age matched controls, or with BPH (2.46 +/- 0.51 pg per ml) was significantly (P less than 0.05) lower than that of age matched controls (3.93 +/- 0.35 pg per ml) and of old beagles with BPH is not associated with increased serum concentrations of androgens, or changes in serum levels of gonadotropins, but may be related to some change in estrogen biosynthesis or metabolism. In the second part of the experiment, castrate and intact beagles were treated for 4 months with three weekly injections of T, DHT, 3 alpha-diol, estradiol, T + estradiol, DHT + estradiol, or 3 alpha-diol + estradiol. As expected, the serum concentration of T, DHT, 3 alpha-diol, estradiol, LH, and FSH varied dramatically depending on the steroid regimen used. Analysis of these results showed that prostate weight was increased by steroid treatments which elevated the serum DHT concentration. However, glandular hyperplasia, indistinguishable from that seen in dogs with BPH, occurred only when estradiol was added to those steroid treatments which caused elevated serum DHT concentration.

Androgens↗

PubMed1980

Testosterone secretion by rat, rabbit, guinea pig, dog, and hamster testes perfused in vitro: correlation with Leydig cell ultrastructure.

Stereological methods were employed to determine volume and surface densities of cytoplasmic organelles in Leydig cells of hamster, rat, rabbit, dog, and guinea pig testes. Contralateral testes were perfused in vitro with maximally stimulating gonadotropin concentrations to determine the capacity of these testes to secrete testosterone. Significantly different amounts of testosterone were secreted by in vitro perfused testes of the five species when maximally stimulated with ovine LH. Significant differences also were seen in the volume and surface densities of smooth endoplasmic reticulum, mitochondria, rough endoplasmic reticulum, and lipids in Leydig cell cytoplasm of the five species. Most interestingly, linear positive correlations were seen between testosterone secretion and smooth endoplasmic reticulum volume (r = 0.99) and surface (r = 0.99) densities. Thus, virtually all of the differences in testosterone secretion by maximally stimulated testes of five species could be accounted for by between-species differences in the amount of Leydig cell smooth endoplasmic reticulum.

Animals↗

PubMed1979

Measurement of testosterone with a high-performance liquid chromatograph equipped with a flow-through ultraviolet spectrophotometer.

A technique is described for measuring nanogram amounts of testosterone using high-performance liquid chromatography with detection by a flow-through spectrophotometer. The addition of a non-radioisotopic internal standard (4-androsten-11 beta-ol-3,17-dione) to the biological specimen automatically corrects for testosterone losses due to extraction and non-quantitative sample injection into the high-performance liquid chromatograph. This new method, which can be performed by inexperienced personnel, is shown to be rapid, precise, accurate and specific for testosterone.

Animals↗

PubMed1979

Celite column chromatography followed by reversed-phase high-performance liquid chromatography: a simple, two-step method for separating 14 testicular steroids.

The separation of 14 major testicular steroids has been effected by a simple, two-step procedure involving Celite column chromatography followed by reversed-phase high-performance liquid chromatography. The technique does not alter the resolved steroids, which are then available for subsequent analysis.

Chromatography, High Pressure Liquid↗

PubMed1979

Testosterone secretion by rat, rabbit, guinea pig, dog, and hamster testes perfused in vitro: correlation with Leydig cell mass.

Testes from guinea pigs, rabbits, dogs, rats, and hamsters perfused in vitro with maximally stimulating concentrations of ovine LH released 9.76 +/- 2.05, 12.80 +/- 3.15, 28.94 +/- 3.01, 3.18 +/- 0.41, and 0.70 +/- 0.12 microgram testosterone (T)/h, respectively. Adjusting for differences in testicular weight did not eliminate significant (P less than 0.01) species variation in testicular capacity for T secretion in response to ovine LH. Similarly, correction for Leydig cell mass, as determined by morphometric analysis, still left significant (P less than 0.01) differences in the testosterone secretion rates in response to ovine LH for guinea pigs (262.5 +/- 38.6 micrograms T/g Leydig cell), rabbits (205.5 +/- 50.7 micrograms T/g Leydig cell), dogs (116.4 +/- 14.8 micrograms T/g Leydig cell), rats (83.55 +/- 21.80 micrograms T/g Leydig cell), and hamsters (18.24 +/- 3.55 micrograms T/g Leydig cell). The data suggest that significant between-species variation of T production in response to ovine LH is not due to quantitative differences in the mass of Leydig cells.

Animals↗

PubMed1979

Age-related changes in conversion of 5 alpha-androstan-17 beta-ol-3-one to 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol by rat testicular cells in vitro.

Conversion of labelled 5 alpha-androstane-17 beta-ol-3-one (DHT) by isolated testicular cells from rats of different ages was examined under saturating substrate conditions in vitro (5--10 micrograms DHT/ml in a 24 h incubation). Two detectable metabolites of DHT were produced by testicular cells in vitro. 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol) and 5 alpha-androstane-3 beta, 17 beta-diol (3 beta-diol). Production of these diols during a 24 h period was linear, and the amounts formed were directly related to the cell number. The amount of 3 alpha- and 3 beta-diols formed by testicular cells of rats of different ages increased from Day 10 to Day 25, then declined. Testicular cells from rats 10 to 20 days of age converted DHT mainly to 3 alpha-diol, but thereafter 3 beta-diol was the predominant testicular metabolite of DHT.

Aging↗

PubMed1978

Surgical morbidity after mastectomy operations.

The records of 146 consecutive patients with mastectomy operations over a three year period were reviewed. Of these, ninety-three (63.6 per cent) had one or more complications secondary to surgery. There were 175 complications, of which complications, of which 107 (73.2 per cent) were wound-related. Seroma formation occurred most frequently but was of minor consequence. The incidence of flap necrosis was 19.1 per cent, with cellulitis or suppurative infection appearing in thirteen patients. Immediate postoperative edema of the arm was fairly rare (2.7 per cent) and appeared related to delayed wound healing. Postoperative complications after total, modified radical, and radical mastectomy present problems unique from those seen after other major surgery, in that local complications predominate. The very nature of the procedure, with the creation of large thin skin flaps, extensive axillary dissection, and an open wound for a prolonged period of time, predisposes to wound morbidity.

Adult↗

PubMed1977