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Biomedical subjects

T M Jones

Publications and source records attributed to T M Jones.

At least 73 records · Page 4Linked to original sources

Disposition of an immunoglobulin intravenous preparation in very low birth weight neonates.

To assess the disposition, tolerance, and toxicity of an intravenous preparation of immunoglobulin (IGIV) in very low birth weight (VLBW) neonates, we administered single doses of 500 or 750 mg/kg to 20 neonates with birth weights between 750 and 1500 g during the first week of life. The infusion of this product was well tolerated. Modest changes in hemoglobin, hematocrit, and total hemolytic complement occurred as expected. Hepatic toxic effects were not detected. Mean peak IgG concentrations were 1564 and 1316 mg/dL for the high-dose and low-dose groups, respectively. Mean IgG concentrations were very similar for both groups on postinfusion days 1, 4, 7, 14, 21, and 28. IgG concentrations remained above 300 mg/dL in seven of 10 infants in each group by day 21, and in six of the high-dose group and seven of the low-dose group by day 28. Mean elimination half-lives were 22.6 and 22.8 days in the high-dose and low-dose groups, respectively. These data provide a basis for assessment of potential efficacy of IGIV in the prevention of late-onset infection in VLBW neonates.

Humans↗

Hyperprolactinemia and male infertility.

Four patients suffering from oligospermia and infertility were found to have slightly to moderately elevated serum prolactin levels consistently. Their testicular biopsy specimens showed varying degrees of impairment of spermatogenesis ranging from hypospermatogenesis to complete absence of germ cells. The usual known causes of hyperprolactinemia, such as pituitary or suprasellar tumors, hypothyroidism, intake of certain medications that deplete the dopamine levels of the hypothalamus or block the action of dopamine on the pituitary, were absent. These patients are described in view of recent clinical and experimental reports implicating hyperprolactinemia as a cause of male infertility.

Adult↗

Response of patients with amyotrophic lateral sclerosis to testosterone therapy: endocrine evaluation.

Four men with amyotrophic lateral sclerosis (ALS) were treated with 200 mg of intramuscular testosterone weekly. Endocrine evaluation, using a gonadotropin-releasing hormone infusion test, indicated the expected degree of suppression of pituitary luteinizing hormone and follicle-stimulating hormone production. These data suggest that testosterone's (androgen) interaction with its receptors in the hypothalamic-pituitary axis is normal in patients with ALS.

Amyotrophic Lateral Sclerosis↗

Parameters of response to clompiphene citrate in oligospermic men.

Twenty oligospermic young men have undergone a 6-month trial of intermittent low dose clomiphene therapy. Three-fourths of the patients enjoyed an increase in semen quality and 8 patients impregnated their wives. Plasma luteinizing hormone, follicle-stimulating hormone and testosterone levels increased in all patients on clomiphene. Development of stringent criteria for the use of clomiphene citrate should result in a conception rate of more than 50 per cent in selected patients. Hypotheses concerning the mechanism of therapeutic response to clomiphene included the induction of higher levels of testosterone locally around the germinal epithelium and the induction of increased follicle-stimulating hormone levels.

Clomiphene↗

Comparison of healing following periodontal surgery with and without dressings in humans.

Seven patients with chronic moderate to severe generalized periodontitis requiring periodontal flap surgery were selected for study. Internally beveled full thickness, apically positioned flaps with osseous recontouring were performed in 20 quadrants. Half the quadrants received a noneugenol dressing, and the other half were left undressed. Fluid Index, Gingival Index, inflammatory index, pocket depth and patient comfort were studied up to 16 weeks postoperatively. Results showed no difference in these parameters between quadrants where periodontal dressings were or were not used following surgery. The patients reported more pain and discomfort and the pain and discomfort was more severe postoperatively when the dressing was used. The results of this study suggest that a surgical dressing serves no useful purpose when periodontal flap surgery is performed.

Adult↗

Direct inhibition of Leydig cell function by estradiol.

Suppression of plasma testosterone levels from a mean of 760 ng/dl to a mean of 295 ng/dl could be induced in normal young adult men 24 h after a single injection of 2 mg aqueous 17 beta-estradiol. Maximum suppression to 123 ng/dl was noted 36 h after estradiol administration. Neither LH nor FSH levels were similarly affected. After administration of 5000 IU hCG to a similar group of subjects, daily blood samples were obtained for testosterone and estrogen. Maximum testosterone levels of 2060 ng/dl (basal, 784 ng/dl) were seen 96 h after hCG administration. Maximum estrogen levels of 13 pg/ml (basal 73 pg/ml) were seen 36 h after hCG administration. The testosterone response to hCG could be attenuated by preceding hCG administration with an injection of 17 beta-estradiol. These results can be explained by the concept of enzyme inhibition; estrogen acts directly on the Leydig cell to effect changes in the activities of certain enzymes important for testosterone synthesis. Whether endogenous estrogen production by the Leydig cell may be important in this postulated short loop feedback is as yet unclear.

Adult↗

Mal perforans and spina bifida occulta.

A 26-year-old man had mal perforans pedis as the principal manifestation of spina bifida occulta with an associated intradural lipoma. Two lumbosacral dimples and a tuft of hair overlying the spina bifida led to the diagnosis. We include a review of the causes of mal perforans and a review of spina bifida occulta and associated abnormalities.

Adult↗

Pathological aspects of the infertile testis.

In this review, the pathological findings from testicular biopsies of men suffering from various types of infertility are presented. The causes of male infertility are divided into three major categories: pretesticular, testicular, and post-testicular causes. The pre-testicular causes of infertility may be defined as extra-gonadal endocrine disorders, such as those originating in the hypothalamus, pituitary, or adrenals, which have an adverse effect on spermatogenesis. The testicular causes of infertility are primary defects of the testes. The post-testicular causes of infertility consist primarily of obstructions of the ducts leading away from the testes. Cases in which the spermatozoa are normal in number but greatly impaired in motility, presumably due to faulty maturation or improper preservation of the spermatozoa during their sojourn in the epididymides, or due to biochemical abnormalities of the seminal plasma, are also included in the postesticular category.

Androgens↗

Mucha-Habermann's disease in children: treatment with erythromycin.

Safe therapeutic measures for Mucha-Habermann's disease in children are lacking. Three patients with the disease were treated with erythromycin for systemic effect. Although the series is small and uncontrolled, this approach seemed effective. An anti-inflammatory mechanism related to inhibition of chemotaxis is speculated.

Child↗

Experimental cryptorchidism in adult male rats: histological and hormonal sequelae.

Mature male rats were rendered cryptorchid and followed for up to nine weeks during which serial blood specimens were obtained for multiple hormonal analyses; serial testicular samples were obtained as well. In contrast with control animals, cryptorchid rats showed transient rises in FSH which returned to normal at the end of the study; estrogen levels were high in the final weeks. Plasma testosterone levels were unchanged and LH levels changed little. Light and electron microscopic studies of testicular biopsy specimens showed prompt disruption of spermatogenesis which became more extensive with time. Sertoli cells underwent multiple changes including increased lipid storage and phagocytosis of spermatozoa. Comparisons are made between the sequence of hormonal changes and that of histological changes. In addition, questions are raised concerning the ways in which Sertoli cells are affected by experimental cryptorchidism.

Animals↗

The effects of fluoxymesterone administration on testicular function.

Long term daily administration of fluoxymesterone (9alpha-fluoro-17alpha-methyl-11beta, 17beta-dihydroxyandrost-4-en-3-one) was associated with a modest suppression of sperm production and a profound suppression of testosterone levels in the absence of significant effects on plasma gonadotropin levels. Nine normal male volunteers took either 10, 20, or 30 mg of fluoxymesterone daily for twelve weeks. Plasma samples were obtained for testosterone, estrogen, LH and FSH levels at biweekly intervals before, during and for up to 12 weeks after fluoxymesterone treatment. Samples were obtained for dehydroepiandrosterone sulfate, testosterone binding globulin and free testosterone assays at representative times before, during and after treatment. Although lower sperm counts were observed at several points during both the treatment and follow up periods, significant consistent suppression of spermatogenesis could not be demonstrated. Reduced plasma testosterone levels were seen within 24 h after beginning fluoxymesterone, and further reductions were noted throughout the treatment period. Changes in plasma estrogen levels did not correlate with fluoxymesterone administration. Neither plasma LH nor plasma FSH levels were significantly altered by fluoxymesterone. A short term study utilizing a single dose of fluoxymesterone yielded similar findings. It is proposed that fluoxymesterone has a local effect on the Leydig cell which is not mediated by gonadotropins.

Adult↗

Testicular chromosomal mosaicism and infertility.

A healthy young man with azoospermia and no other endocrinological abnormalties was shown to have chromosomal mosaicism with the cytogenetic errors found only in testicular tissue. Three clones of cells were identified in both meiosis I and meiosis II by cytogenetic analysis of direct testicular smears. Peripheral blood karyotypes and buccal smear preparations revealed no abnormalities. It is postulated that the gonadal cytogenetic defects account for this patient's azoospermia. In addition, it is hypothesized that this type of incomplete spermatogenesis nonetheless produces sufficiet feedback material ("inhibin") so that FSH levels are not affected.

Adult↗