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Biomedical subjects

S S Howards

Publications and source records attributed to S S Howards.

At least 73 records · Page 4Linked to original sources
PubMed1985

Androgens in male rat reproductive tract fluids: hypophysectomy and steroid replacement.

The control of androgen concentrations in the intraluminal fluids of the male reproductive tract is not well understood. The present experiments were performed to determine the effects of hypophysectomy, hypophysectomy plus testosterone (T), and hypophysectomy plus pregnenolone treatment on intraluminal androgen concentrations in the adult rat testis and epididymis. T and 5 alpha-dihydrotestosterone (DHT) concentrations were determined in the vascular, interstitial, and intraluminal compartments of the epididymis. Testicular and epididymal morphology also were examined under light microscopy. Hypophysectomy of at least 5 days duration significantly reduced T and DHT concentrations in serum, tissues, and intraluminal fluids of the reproductive tract. T replacement for 14 days, which produced peripheral T concentrations of 5 ng/ml, did not support intraluminal androgen concentrations in the seminiferous tubules equivalent to controls; rete testis androgen concentrations were similar to controls, however. Pregnenolone administration at 2 mg X rat-1 X day-1 for 14 days did not maintain spermatogenesis nor intraluminal T concentrations in the seminiferous tubules equivalent to controls; however, a low level of spermatogenesis continued when intraluminal and tissue androgen concentrations were maintained at 10-20% of controls by either the testosterone and pregnenolone treatments.

Androgens↗
PubMed1984

Survival following orchiectomy for stage D adenocarcinoma of the prostate.

The survival of nonprivate and private patients following orchiectomy for stage D adenocarcinoma of the prostate was studied. While the private patients enjoyed a longer survival, their improved survival was found to be a function of an earlier presentation. Examination of the survival statistics with linear regression analysis suggested that survival following orchiectomy is a function of the age at the time of orchiectomy.

Adenocarcinoma↗
PubMed1984

Varicocele.

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Animals↗
PubMed1984

Detection of enteric-urinary fistulas with a noninvasive quantitative method.

The 51chromium test is an inexpensive, noninvasive test to evaluate patients for enteric-urinary fistulas. Of 11 patients studied the 51chromium test demonstrated correctly a fistula in 5 of 6 patients with fistulas and showed no lesion in all 5 without fistulas. Excretory urography, barium enemas, visible contrast medium, cystograms and upper gastrointestinal series failed to demonstrate the fistulas with similar accuracy. Cystoscopy suggested a possible lesion in 4 patients but was definite for a fistula in only 2 of those patients.

Adult↗
PubMed1984

Varicocele: reversal of the testicular blood flow and temperature effects by varicocele repair.

An experimental left varicocele was created in the adult rat by partial ligation of the left renal vein. A varicocele repair was performed by high ligation of the internal spermatic vein. Testicular blood flow and temperature changes were measured in control and sham animals, animals 30 days after establishment of varicocele and animals 30 days after varicocele repair. There was a statistically significant (p less than or equal to 0.01) bilateral elevation of testicular blood flow and temperature in the varicocele group compared to control and sham groups. Varicocele repair returned these blood flow and temperature values to normal. Average testicular blood flow for control, varicocele, sham varicocele and varicocele repair animals were 29.6 +/- 1, 39.8 +/- 2, 30.7 +/- 1 and 29.8 +/- 1 ml. per min. per 100 gm. tissue, respectively. Testicular temperatures averaged 34.4 +/- 0.1, 35.3 +/- 0.2, 34.4 +/- 0.1 and 34.5 +/- 0.1 degrees C, respectively. It is possible that the elevation in blood flow is associated with the elevation of intratesticular temperature, which is known to impair spermatogenesis. The data support a relationship between the varicocele and potential testicular damage.

Animals↗
PubMed1984

On the androgen microenvironment of maturing spermatozoa.

Adult anesthetized male rats were submitted to in vivo micropuncture of the seminiferous and epididymal tubules and reproductive tract vasculature to obtain fluids for analysis of testosterone, 5 alpha-dihydrotestosterone, and androgen-binding protein (ABP). Androgen and ABP concentrations were determined by RIA. The highest concentrations of testosterone (73.14 +/- 5.12 ng/ml) were in testicular interstitial fluid. A significant downhill concentration gradient exists between testosterone concentrations in testicular interstitial fluid and seminiferous tubule fluid (50.24 +/- 2.26 ng/ml); another significant decrease occurs between seminiferous tubule fluid and rete testis fluid (17.85 +/- 2.11 ng/ml). 5 alpha-Dihydrotestosterone concentrations were highest in intraluminal caput epididymidal fluids (58.73 +/- 6.48 ng/ml) as were ABP concentrations (33.30 +/- 2.40 mu leq/microliter). Intraluminal sperm concentrations were also determined, and from these data, fluid reabsorption by the efferent ducts and epididymal tubules were calculated. Eighty-nine percent of the fluid leaving the testis is reabsorbed between the rete testis and caput epididymidis, and 96% is reabsorbed between rete and cauda. It was calculated that large losses of androgen and ABP also occur from the lumen of the excurrent duct system. These losses may be due to metabolism, diffusion from the lumen, or uptake by cells.

Androgen-Binding Protein↗
PubMed1983

The transepithelial movement of 3H-3-O-methyl-D-glucose in the hamster seminiferous and cauda epididymidal tubules.

Studies were performed in male hamsters to determine whether antiluminal, active glucose transport played a role in maintaining low glucose concentrations in male reproductive tract fluids. Studies of tissue uptake of 3H-3-O-methyl-D-glucose (3H-3OMG) demonstrated that after equilibrium seminiferous tissue 3H-3OMG concentrations were similar to blood plasma concentrations. Previous studies have shown that under similar circumstances seminiferous tubule lumen fluid 3H-3OMG concentrations are much lower than blood plasma concentrations. These facts suggested the possible presence of an antiluminal, active transport system for glucose in the seminiferous epithelium. In vivo perfusion of seminiferous tubules with fluids containing 3H-3OMG demonstrated an approximately 80% removal of the isotope after 1.5 hours. This movement was against a blood-lumen glucose gradient and was consistent with antiluminal active glucose transport. Increasing phloridzin concentrations in intraluminal perfusion fluid tended to be associated with decreased removal of 3H-3OMG from the lumen fluid; however, this effect was not significant; thus the evidence failed to support a hypothesis of an active antiluminal glucose pump in the seminiferous epithelium. Movement of 3H-3OMG across the cauda epididymidal epithelium was limited in both the pro- and antiluminal direction. The blood-epididymal barrier for 3H-3OMG movement appears to be much more restrictive than the blood-seminiferous tubule barrier for the same molecule.

3-O-Methylglucose↗
PubMed1983

Impotence: are the newer diagnostic methods a necessity?

Until recently our evaluation of impotent men included a psychiatric evaluation, and history and physical examination by a urologist to determine whether the impotence was organic or psychogenic. After the introduction of specific laboratory methods, such as nocturnal penile tumescence monitoring and penile blood pressure studies, clinicians relied heavily on these tools. We evaluated 33 impotent patients and compared the results of the laboratory methods to the initial diagnoses of the psychiatrist and the urologist to determine if the new methods would confirm our initial impressions or uncover different diagnoses. Thirteen patients were considered to have psychogenic impotence by the clinicians and only 1 patient in this group had evidence of organicity when the laboratory tests were used. Twelve patients were considered to have organic impotence by the clinicians and this was confirmed in 75 per cent of the cases by laboratory testing. Thus, clinical evaluation predicted the outcome of laboratory methods in 92 per cent of the psychogenic group and 75 per cent of the organic group. In addition, postage stamps were used during nocturnal penile tumescence monitoring and in predicting the outcome of nocturnal tumescence monitoring the stamp test had a sensitivity and a specificity of 91 per cent. Many patients presenting with erectile impotence can be evaluated adequately by a psychiatrist and a urologist without the support of expensive laboratory tests. The postage stamp test is useful when nocturnal penile tumescence monitors are not available. Finally, the Minnesota Multiphasic Personality Inventory is of limited value as a screening device.

Blood Pressure↗
PubMed1983

The effect of sympathomimetic drugs on post-lymphadenectomy aspermia.

A double-blind controlled study of the effects on semen quality of 4 alpha-adrenergic agents with and without antihistamines was conducted in a patient who had failure of emission secondary to retroperitoneal lymphadenectomy for testis cancer. No other controlled studies are available. All of the alpha-adrenergic drugs allowed the patient to produce an ejaculate. The effects were similar. The addition of antihistamine did not improve the semen quality. Four days of treatment were consistently more effective than a single dose, especially for sperm motility. A pregnancy resulted. It is concluded that long-term treatment with alpha-adrenergic drugs is indicated in men with failure of emission secondary to retroperitoneal lymphadenectomy.

Adult↗
PubMed1983

A geographic cluster of testicular seminomas.

There have been many reports of space-time clusters of patients with Hodgkin's disease, childhood leukemia and Burkitt's lymphoma. We present a tight space cluster of 4 men with pathologically confirmed testicular seminomas. None of the men had any known reason to be at increased risk for testicular cancer. They all lived in the same immediate neighborhood for at least 7 years. There were 2 sources of potential carcinogens in the area. It is concluded that testicular cancer may have developed in these men as a result of exposure to environmental carcinogens.

Adult↗
PubMed1983

The effect of spironolactone on the elemental composition of the intraluminal fluids of the seminiferous tubules, rete testis and epididymis of the rat.

Embryologically, the epididymis and renal collecting tubules develop from the mesonephric duct. Aldosterone enhances the reabsorption of sodium from the collecting tubule, and there is evidence that sodium is removed from the epididymal lumen against a concentration gradient. Rats were treated with spironolactone, an aldosterone antagonist, and the concentrations of seven elements, including sodium, were measured in intraluminal fluids from the testis and epididymis. The sodium concentration in caput epididymidal fluid rose (102.5 +/- 4.4 to 128.0 +/- 6.8 mmol./l., p less than 0.01) after 14 days of spironolactone treatment. This finding is consistent with the hypothesis that aldosterone acts on the caput epididymidis, like the collecting tubule, to augment the removal of sodium from luminal fluid.

Animals↗
PubMed1983

The effects of cyproterone acetate on the elements in the intraluminal fluids of the testis and epididymis of the rat.

Spermatozoal maturation and the integrity of the epididymis are dependent on the action of androgen. Micropuncture techniques and electron probe microanalysis were used to investigate the effect of cyproterone acetate on the concentrations of seven elements in intraluminal fluids of the testis, rete testis, and epididymis. After 4 weeks of treatment with cyproterone acetate, the sodium concentration rose in the corpus epididymidis (74.4 +/- 5.4 to 102 +/- 6 mmol/L, p less than 0.01). The concentration of potassium rose in seminiferous tubular fluid (33.9 +/- 2.7 to 49.4 +/- 4.4 mmol/L, p less than 0.01) and caput epididymidal fluid (15.9 +/- 1.4 to 25.7 +/- 0.9 mmol/L, p less than 0.01) after 8 weeks of cyproterone acetate treatment. The chloride concentration rose in the caput (23.7 +/- 0.8 to 65.4 +/- 12.5 mmol/L, p less than 0.01) and distal cauda (39.4 +/- 4.6 to 74.7 +/- 10.8 mmol/L, p less than 0.01) epididymidis after 8 weeks of treatment. Cyproterone acetate had no effect on the concentrations of phosphorus, calcium, and magnesium. The sulfur concentration rose in seminiferous tubular fluid (4.3 +/- 0.3 to 7.3 +/- 0.3 mmol/L, p less than 0.01) and distal cauda fluid (5.3 +/- 0.5 to 14.0 +/- 1.6 mmol/L, p less than 0.01) after 8 weeks of treatment with cyproterone acetate. Four weeks of treatment also increased the sulfur concentration in the distal cauda (6.8 +/- 1.6 to 13.4 +/- 1.5 mmol/L, p less than 0.01). Cyproterone acetate treatment did not affect the concentration of any element in rete testis fluid or serum.

Animals↗
PubMed1982

Testicular relapse in acute childhood leukemia.

The successful induction and maintenance of hematologic remission in childhood acute leukemia has led to the recognition of extramedullary leukemia as a major clinical problem [1-6]. The central nervous system is the most common site of extramedullary relapse [1,7-12]. A more recently recognized form of extramedullary relapse is the testis [13-22]. This paper will review a series of patients with childhood acute leukemia who suffered testicular relapse. Modes of therapy for testicular relapse and research conducted into the etiology of testicular relapse will be discussed.

Acute Disease↗
PubMed1982

Infertility.

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Chlamydia Infections↗
PubMed1982

Rat testis and epididymis can transport [3H] 3-O-methyl-D-glucose, [3H] inositol and [3H] alpha-aminoisobutyric acid across its epithelia in vivo.

The in vivo movement of [3H] 3-0-methyl-D-glucose ([3H] 30MG), [3H] L-glucose, [3H] inositol and [3H] alpha-aminoisobutyric acid ([3H] alpha AIB) into and across the rat testicular and epididymal epithelium was investigated. After systemic infusion of [3H] 30MG, both epididymal and testicular tissue concentrations of the isotope were approximately 50% lower than blood plasma levels, even 24 h after infusion. Similar results were observed for caput and seminiferous tubule fluid. There was a significant reduction of [3H] 30MG caput lumen to blood ratio when the blood glucose concentration was increased to 2-5 times that of normal. A similar reduction of [3H] 30MG caput lumen to blood ratio was observed when 1000 mumol of 2-methylaminoisobutyric acid (meAIB) was infused with the isotope. Caput luminal [3H] L-glucose concentration never exceeded 10% of blood levels. The data suggest that glucose is transported across the testicular and epididymal epithelium via a facilitated diffusion mechanism (carrier mediated) and that the carrier is situated on the basolateral membrane. This study did not demonstrate either a glucose countertransport system or a glucose-inositol exchange system across the epithelium of the caput epididymidis. Epididymal tissue (except cauda) and caput luminal fluid concentrations of [3H] inositol exceeded that of blood plasma within 1 h after infusion of isotope. The proximal regions of the epididymis demonstrated significantly higher transporting activity than either cauda or testis. Systemic infusion of 100 mumol myo-inositol significantly reduced the transport of [3H] inositol into caput luminal fluid and epididymal and testicular tissue. It is suggested that there is a carrier situated on the basolateral membrane which is able to transport inositol against a concentration gradient (probably active transport). Epididymal tissue (except cauda), testicular tissue and caput luminal fluid concentrations of [3H] alpha AIB also exceeded that of blood plasma but only 24 h after infusion of isotope. The initial segment and corpus regions of the epididymis had a significantly higher transporting activity compared to the remainder of the epididymis and the testis. A dose of 500 mumol meAIB reduced epididymal uptake of [3H] alpha AIB. These results suggest that there is a carrier situated in the basolateral membrane which can transport the amino acid against a concentration gradient (probably active transport). The differences in transport activities of the compounds investigated along the reproductive tract probably indicate differences in the affinity or quantity of the carriers. These epididymal transporting systems regulate the movement of material across its epithelium and may help to protect the epididymis from fluctuations in the blood concentration of each compound.

3-O-Methylglucose↗