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Biomedical subjects

H W Baker

Publications and source records attributed to H W Baker.

At least 199 records · Page 11Linked to original sources
PubMed1977

Nuclear accumulation of androgens in perfused rat accessory sex organs and testes.

The uptake of androgens into the nuclei of caput epididymis, ventral prostate, seminal vesicle and testis was studied by recirculating physiological and pharmacological concentrations of [3H]testosterone in an artificial medium through the lower half (hemicorpus) of castrated or hypophysectomized rats. The accumulation of dihydrotestosterone in accessory sex organ nuclei was saturable, inhibited by perfusion of excess testosterone or cyproterone acetate, and associated with binding to 3S salt-extractable molecules. In castrated preparations the mean saturation levels (pmol/mg DNA) were different in the three organs: seminal vesicle, 2.8; ventral prostate, 1.8; caput epididymis, 0.9. The saturation level was significantly lower in ventral prostate of hypophysectomized rats (1.2) treated with testosterone to regenerate the accessory sex organs. Testosterone was the major nuclear androgen in the testes of mature hypophysectomized preparations perfused with testosterone. Although there was a large amount of nonspecific accumulation, testosterone binding to 3S molecules was shown by sucrose gradient centrifugation. Binding of dihydrotestosterone to 3S molecules in testicular nuclei was also demonstrated. The ratio of dihydrotestosterone to testosterone was different in immature and mature testicular nuclei and was altered by treatments known to affect testicular 5 alpha-reductase activity. The results suggest that in rat accessory sex organs and immature testis the major active androgen is dihydrotestosterone, whereas in mature testis it is testosterone. The shift in the predominant nuclear androgen in the testis from dihydrotestosterone to testosterone is most simply explained by the maturational change in 5 alpha-reductase activity.

Androgens↗
PubMed1977

Evaluation of methods for perfusing rat testes.

Organ perfusion methods offer a number of advantages in biologic studies but require full characterization before application. Two new methods for perfusing rat testes were characterized and compared with recirculating hemicorpus system. These preparations, selective and isolated testicular perfusion, are nonrecirculating and consequently, allow direct measurement of testosterone secretion. In both systems, testosterone production was a fuction of the dose of human chorionic gonadotropin in the perfusion medium up to 1000 mIU per ml which appeared to be inhibitory. The isolated testis method, in comparison with the selective, is more sensitive to human chorionic gonadotropin, requires less perfusion medium, maintains normal blood flow rates and water content, and is associated with no ischemia at commencement of perfusion. However, this system does not retain normal levels of ATP and GTP after 3 hr of perfusion. Whereas both procedures may be used for studies of testosterone secretion and androgen receptors, the inability to maintain testicular ATP and GTP levels indicates that present methods are not suitable for study of processes dependent upon high energy phosphate metabolism.

Adenosine Triphosphate↗
PubMed1976

Transfer factor therapy in patients with cancer.

The objective of this study was to utilize transfer factor to stimulate cell-mediated immunity to specific tumor antigens in cancer patients. Thirty-five selected patients with advanced recurrent cancer, who were not suitable for further conventional therapy, were treated with transfer factor. Transfer factor was prepared from cohabitants of the patients and administered at 2-week intervals. This immunotherapeutic approach produced a clinical effect in 13 patients in terms of regression of tumor (1), arrest of metastatic disease (14), or pain relief (14). Conversion of dermal reactivity to specific tumor antigens was observed during periods of clinical improvement. Despite continued immunotherapy, the duration of clinical improvement was short (2 weeks to 12 months). Seven of the 11 patients not responding to therapy exhibited serum blocking of lymphocyte responsiveness. In 11 patients there is insufficient data to evaluate the clinical effectiveness of this therapy. The results suggest that transfer factor can stimulate specific cell-mediated immunity in cancer patients and produce a clinical effect on tumor under certain circumstances.

Antigens, Neoplasm↗
PubMed1976

Clinical staging of cancer of the head and neck: a new "new" system.

A revised clinical staging system for cancers arising in head and neck sites has been prepared. It utilizes a uniform N classification for cervical node metastases. The T classifications describing the extent of the primary tumor are generally similar but differ in specific details for each site. Although the present system makes use of past field trials and more recent clinical studies, it cannot be considered final. Clinicians managing cancer in head and neck sites are encouraged to test the system with their own patient data to elicit further areas for improvement.

Head and Neck Neoplasms↗
PubMed1976

Changes in the pituitary-testicular system with age.

In order to provide a comprehensive account of pituitary-testicular function in man, 466 subjects, ranging in age from 2 to 101 years, were studied to examine blood levels of the pituitary gonadotrophins (LH and FSH), the sex steroids testosterone and oestradiol, the binding capacity of the sex hormone binding globulin (SHBG), the free testosterone and oestradiol fractions, and the transfer constant for the peripheral conversion of testosterone to oestradiol. The results were compared with clinical indices of testicular size, sexual function and secondary sex hair distribution. Serum LH and FSH were low before puberty, increased in pubertal adolescents to levels somewhat above those of adults and subsequently increased progressively over the age of 40 years. Testosterone levels fell slowly after the age of 40, while there was a slight rise in plasma oestradiol with increasing age. FSH and testosterone showed small seasonal variations in young adult men, the lowest values being seen in winter. SHBG binding capacity was high in two prepubertal boys, fell in adult men, but increased in old age. Free testosterone and oestradiol levels fell in old age. The metabolic clearance rates (MCR) of testosterone and oestradiol also fell in old age, while the conversion of testosterone to oestradiol was increased. Many correlations were observed between various hormonal and clincial measurements. The evidence is consistent with a primary decrease in testicular function over the age of 40 years.

Adolescent↗
PubMed1976

A study of the endocrine manifestations of hepatic cirrhosis.

The clinical features and hormonal abnormalities were surveyed in 117 men with cirrhosis of the liver. Compared with healthy men of similar ages, the patients had significantly lower metabolic clearance rates, plasma production rates and total and free levels of testosterone, reduced testosterone responses to human chorionic gonadotrophin stimulation, higher oestradiol, luteinizing hormone and follicle stimulating hormone levels and higher binding capacities of sex steroid binding globulin. The peripheral conversion of testosterone to oestradiol was also found to be significantly increased. However, the metabolic clearance and plasma production rates of oestradiol were not significantly different from those of healthy men. Patients who were severely ill with liver failure and one with haemochromatosis had low levels of luteinizing hormone and follicle stimulating hormone and sub-normal responses to clomiphene and luteinizing hormone-releasing hormone. Higher plasma oestradiol levels were found in patients with gynaecomastia and spider naevi than in those without these signs. However, the clinical features of androgen deficiency--that is, testicular atrophy, impotence and loss of secondary sex hair--were only poorly related to the low testosterone levels, and production rates and longtitudinal studies indicated that the hormonal levels, endocrine features and severity of the liver disease could change independently. It is concluded that the clearance of oestradiol from plasma is not limited by liver disease in all patients, and that reduced degradation of oestrogens is not the initial event in the sequence leading to the hormonal abnormalities of cirrhosis. While gonadotrophin deficiency occurs with liver failure and in some patients with haemochromatosis, the more usual findings are of elevated gonadotrophin levels and a poor Leydig cell response to chorionic gonadotrophin. These suggest that the hypogonadism is primary in most patients with cirrhosis. The causes of the high oestradiol levels were not discovered. Increased peripheral conversion of precursors to oestradiol or increased testicular secretion of oestradiol are possibilities. The high binding capacities of sex steroid binding globulin were not significantly correlated with either the low testosterone or high oestradiol level and the cause of this abnormality remains uncertain. The low metabolic clearance rates of testosterone appeared to result from the increased plasma protein binding of testosterone. The discrepancies in the expected relationships between the hormone and clinical changes suggest that factors other than those studied are also involved in the genesis of the endocrine features of hepatic cirrhosis.

Adult↗
PubMed1975

The assessment of results following endocrine therapy for prostatic cancer.

Generally, recent reports on the side effects of estrogen therapy for prostatic cancer have concerned mortality statistics, relatively little attention having been paid to the quality of life of individual patients. We herein propose an assessment of treatment regimens based on the concept of the time during which a patient remains free of tumor progression or serious side effects. A particular regimen has been examined in relation to the hormonal effects of endocrine ablation, and to the dosage and type of estrogen therapy used in 59 men with prostatic cancer. Although no significant difference among treatment methods has emerged in this small group (except for the more frequent occurrence of fluid retention with the stilbestrol dosage, 30 versus 15 mg. per day) and no correlation between the degree of testosterone suppression and length of remission has emerged so far, this method of assessment proved useful and should be applicable widely. It was confirmed that gonadotropin levels remained in the normal range in patients whose testosterone levels were suppressed with chlorotrianisene.

Chlorotrianisene↗
PubMed1975

Hormonal studies in Klinefelter's syndrome.

Some aspects of the hormonal abnormalities of Klinefelter's syndrome have been studied in nineteen patients. As a group the plasma production rate, the total and free levels of testosterone, and the metabolic clearance rates of testosterone and oestradiol were low. Plasma oestradiol, LH and FSH levels were elevated and there was increased peripheral conversion of testosterone to oestradiol. The production rates of oestradiol and the binding capacities of the sex steroid binding globulin were normal. There were fluctuations in the blood levels of LH, FSH, testosterone and oestradiol, but these appeared to be less marked than in healthy men. Both LH and FSH levels were suppressed by acute or prolonged testosterone administration and there was no evidence for a differential effect on LH. It is suggested that the threshold for suppression of LH and FSH is increased in hypergonadotrophic states. Although no statistically significant relationships were found between the hormonal and clinical abnormalities of the syndrome it is probable that the hyperoestrogenism and androgen deficiency are linked to the development of the signs of feminization and hypogonadism.

Adolescent↗