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Biomedical subjects

F Wright

Publications and source records attributed to F Wright.

108 records · Page 6Linked to original sources
PubMed1978

Urinary 5 alpha-androstane-3 alpha,17 beta-diol radioimmunoassay: a new clinical evaluation.

A rapid specific and reliable RIA for urinary 5 alpha-androstane-3 alpha,17 beta-diol (Adiol) is described using chromatographical purification and a specific antibody. Values are reported under some physiological and pathological conditions in 179 individuals. In 43 normal adult men, the mean (+/-SD) urinary Adiol excretion was 193 +/- 77 micrograms/24 h, and in 29 normal women it was 44 +/- 23 micrograms/24 h. These values are significantly different (P less than 0.01). In 49 hirsute women, urinary Adiol Excretion was elevated (137 +/- 51 micrograms/24 h) and significantly different from this value in normal women (P less than 0.01). The urinary Adiol excretion in 10 postmenopausal women was very low (less than 5 micrograms/24 h). In normal adult subjects, the theoretical contribution to urinary Adiol of the major secreted androgens was calculated. Whereas dehydroisoandrosterone and dehydroisoandrosterone sulfate yield the same amount of urinary Adiol in both sexes, testosterone is the main precursor of Adiol in men and androstenedione is the main precursor in normal premenopausal and hirsute women. However, the amount of Adiol recovered in the 24-h urine depends not only on the secretion rate of androstenedione and testosterone but is also related to the testosterone 5 alpha-reductase activity present in androgen target cells, especially in sexual skin.

Adolescent↗
PubMed1971

Pulmonary artery pressure and alveolar gas exchange in man during acclimatization to 12,470 ft.

Pulmonary hemodynamics and gas exchange were studied in four physicians during 72 hr acclimatization to 12,470 ft. Pulmonary catheters were left in three subjects for 72 hr. Resting mean pulmonary arterial pressure (PAP) rose progressively during the first 24 hr from 10.3 +/-1.0 to 21.1 +/-4.0 torr and remained at this level. During this same 24 hr period cardiac output increased from 7.1 +/-1.4 to 8.4 +/-2.0 liters/min and total pulmonary resistance rose from 122 +/-16 to 209 +/-40 dynes.sec/cm(-5). Excercise at 60 w after 24 hr of hypoxia increased PAP to 28.8 +/-5.1 torr and decreased total pulmonary resistance to 155 +/-25. Shunt fractions were 11 +/-3.8% after 24 hr at altitude and fell to 7 +/-0% after 72 hr. Alveolar to arterial O(2) difference (P(A-a)(O2)) breathing oxygen fell from 116 +/-10.8 to 92 +/-33.3 torr during the same period of acclimatization, whereas dead space to tidal volume ratio (V(D)/V(T)) rose from 33 +/-4.0% to 40 +/-5.3% and P(A-a)(O2) breathing ambient air rose from 8 +/-2.6 to 11 +/-3.0 torr. Inspiratory static lung compliance decreased significantly from a control of 176 +/-8 to 141 +/-8 ml/cm H(2)O after 72 hr of hypoxia. After 4-7 days at altitude, further deterioration in gas exchange was observed after a 5 mile, 1800 ft climb to the summit (14,255 ft) and return. P(A-a)(O2) on air rose from 2.5 +/-2.1 just before starting, to 16.3 +/-2.8 at the summit (rested), and was still 9.0 +/-2.2 several hours after returning. The O(2)-breathing values paralleled these, whereas dead space appeared to fall. We speculate that the hypoxic pulmonary hypertension which develops over 24 hr in some way may be responsible for a reduction of compliance and deterioration in oxygen exchange efficiency, possibly representing a sub-clinical form of pulmonary edema of high altitude. The increased alveolar to arterial O(2) difference induced by hypoxic exercise persists for several hours of hypoxic rest.

Acclimatization↗
PubMedDate not supplied

Comparison of estrogen concentrations, estrone sulfatase and aromatase activities in normal, and in cancerous, human breast tissues.

In the present study, the concentrations of estrone (E(1)), estradiol (E(2)) and their sulfates (E(1)S and E(2)S), as well as the sulfatase and aromatase activities, were evaluated in post-menopausal patients with breast cancer. Comparative studies of the evaluation of these parameters were carried out in (a) tumor tissue, (b) areas surrounding the tumor, and (c) areas distant from the tumor (glandular tissue) which were considered as normal tissue. The levels (in pm/g; mean +/- SEM) were: for E(1) in the (a) area: 320+/-95; in (b): 232+/-86; and in (c): 203+/-71; for E(2) in the (a) area: 388+/-106; in (b): 224+/-48; and in (c): 172+/-80; for E(1)S in the (a) area: 454+/-110; in (b): 259+/-90; and in (c): 237+/-65; for E(2)S in the (a) area:318+/-67; in (b): 261+/-72; and in (c): 232+/-75, respectively. The values of E(1)S and E(2) were significantly higher in the tumor tissue than in the area considered as normal. In all the tissues studied, the sulfatase activity was much higher than aromatase (130-200). In addition, the sulfatase levels were significantly higher in the peripheral and in the tumor tissue than in the area considered as normal. The levels of aromatase were significantly higher in tumoral than in normal tissue. The present data extend the "intracrine concept" for breast cancer tumors. The physiopathology and clinical significance as promoter parameters in breast cancer is to be explored.

Aged↗
PubMedDate not supplied

Control of sulfatase and sulfotransferase activities by medrogestone in the hormone-dependent MCF-7 and T-47D human breast cancer cell lines.

In the present study, we explored the effect of the progestin medrogestone on the sulfatase and sulfotransferase activities in the hormone-dependent MCF-7 and T-47D human breast cancer cell lines. After 24 h incubation at 37 degrees C of physiological concentrations of estrone sulfate ([3H]-E1S: 5x10(-9) mol/l), it was observed that this estrogen was converted in a great proportion to E2 in both cell lines. Medrogestone significantly inhibits this transformation, at all the concentrations tested (5x10(-8) to 5x10(-5) mol/l), in both cell lines. The IC50 values were 1.93 micromol/l and 0.21 micromol/l in MCF-7 and T-47D cells, respectively. In another series of studies, after 24 h incubation at 37 degrees C of physiological concentrations of estrone ([3H]-E1: 5x10(-9) mol/l), the sulfotransferase activity was detectable in both cell lines. Estrogen sulfates (ES) are found exclusively in the culture medium, which suggests that as soon as they are formed they are excreted into the medium. Medrogestone has a biphasic effect on sulfotransferase activity in both cell lines. At low doses: 5x10(-8) and 5x10(-7) mol/l, this compound stimulates the enzyme by +73.5 and 52.7%, respectively, in MCF-7, and by 84.5 and 62.6% in T-47D cells. At high concentrations: 5x10(-6) and 5x10(-5) mol/l, medrogestone has no effect on MCF-7 cells, but inhibits the sulfotransferase activity in T-47D cells by -31.4% at 5x10(-5) mol/l. In conclusion, the inhibitory effect provoked by medrogestone on the enzyme involved in the biosynthesis of E2 (sulfatase pathway) in estrogen-dependent breast cancer, as well as the stimulatory effect on the formation of the inactive ES, support a probable anti-proliferative effect of this progestin in breast tissue. Clinical applications of these findings can open new therapeutic possibilities for this disease.

Antineoplastic Agents, Hormonal↗
PubMedDate not supplied

A Bayesian model for detecting past recombination events in DNA multiple alignments.

Most phylogenetic tree estimation methods assume that there is a single set of hierarchical relationships among sequences in a data set for all sites along an alignment. Mosaic sequences produced by past recombination events will violate this assumption and may lead to misleading results from a phylogenetic analysis due to the imposition of a single tree along the entire alignment. Therefore, the detection of past recombination is an important first step in an analysis. A Bayesian model for the changes in topology caused by recombination events is described here. This model relaxes the assumption of one topology for all sites in an alignment and uses the theory of Hidden Markov models to facilitate calculations, the hidden states being the underlying topologies at each site in the data set. Changes in topology along the multiple sequence alignment are estimated by means of the maximum a posteriori (MAP) estimate. The performance of the MAP estimate is assessed by application of the model to data sets of four sequences, both simulated and real.

Bayes Theorem↗
PubMedDate not supplied

[Progesterone administered by percutaneous route: an antiandrogen locally useful (author's transl)].

A skin specimen has been obtained from 5 volunteered men submited to a percutaneous administration of progesterone. Plasma progesterone, testosterone and dihydrotestosterone were evaluated before and after this treatment. Progesterone percutaneously administered does not change plasma testosterone and dihydrotestosterone and only slightly increases plasma progesterone. On the contrary, in the skin samples obtained from subjects percutaneously treated by progesterone, radioactive testosterone was not converted to dihydrotestosterone by skin homogenates. In conclusion, progesterone when percutaneously administered inhibits testosterone 5alpha-reduction and may be considered as an antiandrogen locally useful.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMedDate not supplied

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Adult↗
PubMedDate not supplied

[The study of the influence of prolactin on gonadal steroids metabolism by the human chorionic gonadotropin test. Plasma and urinary determinations in 27 subjects (control, hyperprolactinemic, normoprolactinemic but hypogonadic subjects) (author's transl)].

In order to determine whether hyperprolactinemia besides its action at the hypothalamic level, acts at the gonadal level, a serie of 28 stimulations by Human Chorionic Gonadotropin (HCG : 5 000 IU X 3) is reported. The following parameters were measured in plasma and in urine before and during 4 consecutive days following the injection of HCG : Progesterone (P), 17 OH Progestérone (17 OHP), Androstenedione (A), Testostérone (T), Dihydrotesterone (DHT), Estrone (E1), 17 beta estradiol (E2), Urinary Androstanediol (Adiol) Testosterone Glucuronide (G.T.) and phenolsteroids (PS). The test was performed in both sex, in 3 different groups including normal, hyperprolactinemic and normoprolactinemic but hypogonadic subjects (hypopituitarism). These data suggest that in hyperprolactinemic subjects: there is no steroid 5 alpha reductase abnormality in male patients, and there is no gonadal resistance to HCG stimulation in both sex, at least to the high doses of HCG used in this study.

Chorionic Gonadotropin↗