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Biomedical subjects

S S Howards

Publications and source records attributed to S S Howards.

At least 109 records · Page 6Linked to original sources
PubMed1979

Analysis of the feasibility of storing human semen for future artificial insemination.

Patients about to undergo vasectomy, retroperitoneal lymph node dissection, pelvic radiotherapy or chemotherapy frequently wish to store semen for future artificial insemination. The probability that this will result in a pregnancy is approximately 33% and the logistics are complicated. These problems are discussed and a cost analysis is presented. A list of semen banks presently storing homologous human semen and registered with the American Association of Tissue Banks also is presented.

Costs and Cost Analysis↗
PubMed1978

The blood-testis barrier: a morphologic or physiologic phenomenon?

Blood urea is concentrated in rat seminiferous tubule fluid. Data are presented that provide strong evidence that this urea movement is dependent on active sodium transport. In contrast, in the hamster blood urea is excluded partially from the seminiferous tubule. This may be caused by transport of urea from the lumen to the blood rather than secondary to the morphologic blood, testis barrier at the Sertoli to Sertoli cell tight junctions.

Animals↗
PubMed1978

The effects of vasectomy on the movement of 14C-urea in the seminiferous tubule of the hamster.

14C-urea entry into the hamster seminiferous tubule (SNT) and cauda epididymidal tubule was observed in intact males and in animals vasectomized for 2 weeks and for 4 months. 14C-urea entry rate and plateau level were significantly increased 4 months postvasectomy. 14C-urea entry into the cauda epididymidis was significantly altered 2 weeks postvasectomy. 2, 4,-dinitrophenol significantly increased 14C-urea concentration in the SNT. This is compatible with the presence of an outward directed energy dependent movement of urea in the hamster SNT. Increasing 14C-urea concentrations in the postvasectomy SNT may be attributable to a failure or inhibition of this physiologic activity.

Animals↗
PubMed1977

In vivo sodium, potassium, and sperm concentrations in the rat epididymis.

In vivo samples of epididymal fluids were obtained through the use of micropuncture techniques. Microsamples from four areas of the rat epididymis were analyzed for Na+ and K+ concentrations and for sperm density. Na+ values declined significantly from caput to corpus epididymidis (P less than 0.01), while K+ and sperm concentrations increased significantly (P less than 0.01). A large water loss from the epididymal lumen was calculated, as well as net losses of both cations. Water losses may be explained on the basis of an active Na+ pump; however, the effect of the absolute values of epididymal Na+ and K+ concentrations on sperm motility and fertility remains unresolved.

Animals↗
PubMed1977

Experience gained from the management of 9 cases of bilateral renal cell carcinoma.

Radical nephrectomy is the traditional therapy for renal cell carcinoma. However, modification of this technique is necessary when bilateral renal cell carcinoma occurs (3.8 per cent of all renal cell carcinomas at our institution). Special attention should be paid to the contralateral kidney when the diagnosis of renal cell carcinoma is made, since an inapparent contralateral tumor may also be present (2 of 9 cases). An aggressive approach, consisting of in vivo heminephrectomy and a contralateral procedure, has avoided operative mortality or bench surgery, maintained life-sustaining renal function and produced a reasonable long-term survival rate.

Adenocarcinoma↗
PubMed1977

Intercostal nerve block with flank incision.

We studied the postoperative course of 20 consecutive patients with T10 to 12 flank incisions, half of whom had intraoperative bupivacaine intercostal nerve blocks. The nerve block patients required less pain medication (p less than 0.001), ambulated 3 days earlier (p less than 0.001) and took a regular diet 2 days sooner (p less than 0.01) than the control patients.

Abdomen↗
PubMed1977

Micropuncture studies of the motility of rete testis and epididymal spermatozoa.

The effect of cyclic adenosine 3':5'-monophosphate (cAMP) and caffeine on the motility of spermatozoa obtained in vivo by micropuncture from the rat rete testis, caput epidiymidis, and cauda epididymidis was studied. Spermatozoa from all sites were immobile in their native fluid. Rete testis spermatozoa were not motile under any experimental conditions. After dilution in salt solution, some caput sperm exhibited circular motion, whereas most cauda sperm swam progressively. Dextrose enhanced the motility of sperm from both epidiymal sites. Caffeine further increased the motility of epididymal sperm. Dibutyryl cAMP and cAMP stimulated caput spermatozoa but had no effect on cauda spermatozoa.

Animals↗
PubMed1977

Prevention of recurrent urinary tract infections in girls.

Eighteen girls between the ages of 3 and 13 years--with a history of at least three culture-documented episodes of bacteriuria in the previous year, but without radiologic evidence of major urinary tract abnormality--were placed on a double-blind, crossover study comparing the effectiveness of nitrofurantoin macrocrystals against a placebo in preventing the recurrence of bacteriuria. Each child was placed on a daily low dose of nitrofurantoin (1.2 to 2.4 mg/kg/day) or an identical-appearing placebo for six months. Each child was then placed on the opposite capsule for a similar period. There were 35 episodes of bacteriuria (4.2 episodes/patient/yr) in the patients taking the placebo, which compared with a rate of 3.8 episodes/patient/yr during the year prior to the study. Only two episodes (0.2 episodes/patient/yr) occurred in the patients taking the drug. The difference in the rate of recurrent bacteriuria between the girls on placebo and on medication is significant at the 0.01 level using the Wilcoxin matched-pairs test. There were no adverse reactions to the drug. Nitrofurantoin macrocrystals in a single daily low dose appear to be a safe, effective method of preventing recurrent bacteriuria in girls at high risk.

Adolescent↗
PubMed1977

Metabolic effects of unilateral orchiectomy on the guinea pig testis.

Six months after unilateral orchiectomy, there was a significant increase in the RNA and DNA content of contralateral testes as compared with the testes of age-matched normal guinea pigs. The ratio of RNA to DNA was not affected by orchiectomy, suggesting that the compensatory growth was secondary to hyperplasia rather than hypertrophy. Tritiated thymidine uptake by the contralateral testis was elevated at 2 weeks and 2,4 and 6 months after orchiectomy, confirming that increased metabolic activity occurred in the remaining testis after hemicastration.

Animals↗