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Biomedical subjects

M D Mansfield

Publications and source records attributed to M D Mansfield.

12 recordsLinked to original sources
PubMed1986

Hormone levels in the foetal and neonatal prostate.

The prostates of 41 foetuses and neonates have been assayed for testosterone, 5 alpha-dihydrotestosterone (DHT), oestradiol and oestriol and the presence of these hormones has been demonstrated in all cases. Oestriol was found to be present in the highest concentration. A highly significant correlation was found between testosterone and DHT as well as between DHT and oestradiol. The correlation between oestriol and oestradiol was also significant. It has been pointed out that the presence of these hormones is essential for the growth and development of the prostate gland.

Chromatography, Thin Layer↗
PubMed1984

Validation and use of centrifugal ultrafiltration-dialysis in the measurement of percent free oestradiol in serum.

The validity of the centrifugal ultrafiltration-dialysis method in the measurement of the percentage of oestradiol and testosterone which is not bound to protein (free) in human serum was assessed. In an initial validation, the values of % free steroid obtained for oestradiol and testosterone in protein-free ultrafiltrates of human serum were higher than expected. Filter paper discs used in the system were shown to adsorb [3H]oestradiol from protein-free solution. Their replacement with glass-fibre discs, which did not adsorb oestradiol, decreased but did not eliminate the discrepancy between observed and expected results for % free oestradiol in ultrafiltrates. The use of polyethylene rather than polypropylene vials then reduced the discrepancy to insignificant levels. The estimates for % free oestradiol in serum were reduced by these modifications.

Centrifugation, Density Gradient↗
PubMed1980

Familial male pseudohermaphroditism due to deficiency of 5 alpha-reductase.

Two brothers of Greek Cypriot origin, karyotype 46 XY, aged 17 and 19 years were brought up as females because of predominantly female external genitalia with clitoromegaly and urogenital sinus. At puberty there was genital masculinization with testicular enlargment and descent and development of male musculature and body habitus without gynaecomastia. Both subjects acquired male gender identity and changed from a female to a male gender role. The internal genitalia were normally formed with an ejaculate containing mature spermatozoa. In both subjects plasma testosterone levels were slightly elevated, dihydrotestosterone was in the low normal range and the plasma testosterone to dihydrotestosterone ratio was markedly elevated. Plasma oestrogens were normal whereas SHBG binding capacity was elevated. The urinary 5 beta-aetiocholanolone to 5 alpha-androsterone ratios were elevated compared with normal subjects. Basal plasma LH was normal but, the LH response to LHRH was exaggerated and basal and peak plasma levels of FSH were elevated. 5 alpha-reductase activity in genital skin homogenates was higher when androstenedione was used as a substrate, compared with testosterone, suggesting a decreased affinity of the enzyme for testosterone. The clinical and hormonal features in the two siblings are consistent with an impaired peripheral conversion of testosterone to dihydrotestosterone due to deficiency of the enzyme 5 alpha-reductase.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1980

Maternal plasma androgens in early human pregnancy.

Mean maternal plasma levels of testosterone, androstenedione, and 5 alpha-dihydrotestosterone were established from 4 to 16 weeks gestation from twice-weekly blood samples taken from 15 pregnant women. All three hormone levels were raised when compared with the non-pregnant state. There were significant differences in mean maternal plasma testosterone levels at 4 to 5 and 7 to 8 weeks gestation, when comparing women carrying male and female fetuses. Androstenedione levels in a twin pregnancy were increased throughout and testosterone levels were more than 1 SD above the mean from week 15. Steroid levels fell late in the two women who aborted. Hormone levels in three women being given progestogens were within normal limits.

Abortion, Spontaneous↗
PubMed1978

Fructose and hormone levels in semen: their correlations with sperm counts and motility.

Levels of fructose, growth hormone (GH), prolactin (HPr), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and 5alpha-dihydrotestosterone (DHT) were determined in semen. The samples were obtained from patients attending an infertility clinic and separated into four groups according to the number of spermatozoa. Levels of HPr, LH, and FSH showed significant positive correlations with sperm counts. Significant differences in fructose and hormone levels were found between various groups. Expressed as concentrations of hormones or fructose per milliliter of semen, none of the hormones showed a significant negative correlation with sperm motility whereas fructose showed a significant negative correlation. Expressed as amounts per ejaculate of semen, only prolactin showed a significant positive correlation with sperm motility. The significance of these findings is discussed.

Cell Count↗
PubMed1977

The implications of scrotal interference for the preservation of spermatogenesis in the management of testicular tumours.

Seminal analyses have been performed in 14 patients who have received radiation therapy following unilateral orchidectomy for testicular tumours. In patients receiving scrotal in addition to para-aortic and pelvic lymph node irradiation azoospermia occurred in 17 out 18 specimens examined, whereas in those patients not requiring scrotal irradiation, restoration of spermatogenesis occurred. The difference is a result of the increased dose of radiation received by the remaining testicle when the contralateral side of the scrotum is irradiated. Following scrotal aspiration, trans-scrotal biopsy or scrotal orchidectomy for testicular tumour, the scrotum becomes a possible site of recurrence and it should be electively irradiated. In order to give the patient the best chance of preserving fertility it is essential that scrotal interference in the management of testicular tumours must be avoided.

Humans↗
PubMed1977

Amniotic fluid testosterone and fetal sex determination in the first half of pregnancy.

The concentration of freely extractable testosterone in amniotic fluid was measured in 54 patients whose gestational ages ranged from 10 to 20 weeks; 31 of the fetuses were male and 23 were female. The mean amniotic fluid testosterone concentration was significantly higher with a male fetus than with a female fetus. On only 7 out of 31 occasions was the presence of a male fetus associated with amniotic fluid testosterone values below 100 pg/ml, whereas the values associated with a female fetus were never higher than 90 pg/ml. After 14 weeks gestation no amniotic fluid testosterone level was lower than 120 pg/ml in the presence of a male fetus.

Amniotic Fluid↗
PubMed1976

Hormonal assessment before and after vasectomy.

Animal experiments have suggested that vasectomy may disturb the endocrine function of the testis. To explore this possibility in man blood was obtained from 277 men who had undergone vasectomy up to six years earlier or who were about to undergo the operation. Mean plasma testosterone concentrations seemed to be slightly higher in those who had undergone vasectomy than in the preoperative group, although this difference was not statistically significant. There was no significant difference between these two groups in the concentrations of luteinising hormone, follicle-stimulating hormone, prolactin, or oestradiol.

Adult↗
PubMed1972

Androgens.

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Animals↗
PubMed1969

Studies on steroid metabolism in human endometrial tissue.

1. A computerized technique is described for the quantitative determination of radiometabolites from incubation studies. 2. Seven steroid substrates have been incubated with human endometrial tissue. The principal radiometabolites were identified and determined after 2hr. incubation without the addition of cofactors and after 4hr. incubation with cofactors. 3. The main products from progesterone were 20alpha-dihydroprogesterone and 5alpha-pregnanedione with lower yields of 5beta-pregnanedione and 20beta-dihydroprogesterone. There was no evidence for 17alpha-hydroxylase activity. 4. 17alpha-Hydroxyprogesterone was transformed into small yields of 17alpha,20alpha- and 17alpha,20beta-dihydroxypregn-4-en-3-one. In one incubation there was evidence for conversion into androstenedione. 5. Dehydroepiandrosterone was transformed into small amounts of androstenedione, 5alpha-androstanedione and androsterone. 6. Androstenedione and testosterone were interconvertible, the reaction favouring the formation of androstenedione. 5alpha-Androstanedione and androsterone were formed from both substrates. There was no evidence for the formation of phenolic steroids. 7. Oestrone and oestradiol-17beta were interconvertible, the reaction favouring the formation of oestrone.

Dehydroepiandrosterone↗