72 research outputs found

    WHICH TESTOSTERONE REPLACEMENT THERAPY?

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    SUMMARY Three different forms of testosterone (T) replacement therapy were compared; they were the intramuscular injection of mixed testosterone esters 250 mg; the subcutaneous implantation of 6 x 100 mg pellets of fused testosterone; and the oral administration of testosterone undecanoate (TU) 80 mg twice daily. Six hypogonadal males were treated with oral TU for an eight week period, during which time serial serum hormonal estimations were performed over 10 h at the initiation and after four and eight weeks of therapy. Serum T levels showed marked variability both between subjects and within the same subject on different occasions. We attribute this to variability in absorption of TU, which is formulated in oleic acid. The overall mean T level calculated from the areas under the profiles of TU was 12.0 nmol/l. Hormone responses to injected T esters were studied in nine hypogonadal males. Serum T rose to supraphysiological peak concentrations (mean 71 nmol/l) 24-48 h after an injection, followed by an exponential decay to reach baseline concentrations after 2-3 weeks. The overall calculated mean T level in subjects receiving testosterone esters 250 mgevery three weeks was 27.7 nmol/l. Subcutaneous implantation of testosterone in six hypogonadal men produced a gradual rise in serum T followed by a slow decline, with T levels remaining within the normal range for 4-5 months. The calculated overall mean T level over 21 weeks after implantation was 17.0 nmol/l. Serum oestradiol (Ez) levels remained within the normal male range throughout the study periods on both TU and T implant therapy but showed a supraphysiological peak (mean 347 pmol/l) 24-48 h after a T injection. Sa-dihydrotestosterone (DHT) levels appeared to parallel those of T on the three forms of therapy, with DHT:T ratios being highest for TU therapy. This was also true for the target organ metabolite 5a-androstane-3a, 17B-diol. At the doses studied drug costs were similar for T implantation (every 5 months) and Tester injections (every 3 weeks), but were 7-8 times higher for TU (80 mg twice a day). We conclude that T implantation remains overall the most physiological form of androgen replace

    The production of a physiological puzzle: how Cytisus adami confused and inspired a century’s botanists, gardeners, and evolutionists

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    ‘Adam’s laburnum’ (or Cytisus adami), produced by accident in 1825 by Jean-Louis Adam, a nurseryman in Vitry, became a commercial success within the plant trade for its striking mix of yellow and purple flowers. After it came to the attention of members of La Société d’Horticulture de Paris, the tree gained enormous fame as a potential instance of the much sought-after ‘graft hybrid’, a hypothetical idea that by grafting one plant onto another, a mixture of the two could be produced. As I show in this paper, many eminent botanists and gardeners, including Charles Darwin, both experimented with Adam’s laburnum and argued over how it might have been produced and what light, if any, it shed on the laws of heredity. Despite Jean-Louis Adam’s position and status as a nurseryman active within the Parisian plant trade, a surprising degree of doubt and scepticism was attached to his testimony on how the tree had been produced in his nursery. This doubt, I argue, helps us to trace the complex negotiations of authority that constituted debates over plant heredity in the early 19th century and that were introduced with a new generation of gardening and horticultural periodicals

    Clinical experience with the use of two diphosphonates in the treatment of Paget's disease.

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    The effects of EHDP (20 mg/kd/day) and APD (4.5 mg/kg/day) given for three months to patients with severe symptomatic Paget's disease have been compared in an open trial of 17 patients. Both drugs were equally effective in producing a prompt reduction in pair scores, urine hydroxyproline, and serum alkaline phosphatase levels. The remission was maintained for a variable period after stopping treatment. Both drugs were well tolerated, and a one-month course of either drug was not effective. Comparison with published responses from previous studies indicates that EHDP given at this dose as a relatively short course is more effective than a lower dose for a longer period of time; the present study does not suggest that APD has significant advantages

    Time on Task Effects during Interactive Visual Search

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    There is a major shift taking place in airports across the globe, changing from 2D dual-view X-ray screening to 3D CT screening. 3D CT screening is believed to improve target detection since it enables screeners to interact with images of passenger baggage (i.e., rotating and zooming into the displays). The change in screening technology is moving what was once a purely visual search task to an interactive search task. Here, we conducted two experiments with a large sample size during February of 2023 (695 participants) to examine (1) changes in search performance between a simulated dual-view and simulated interactive search task and (2) the effects of time on task upon performance. Consistent with past research, we found that interactive search, when compared with dual-view search, produced higher response accuracy rates coupled with increased reaction times. However, while we found effects of time on task (RTs reduced, and participants became more likely to respond ‘absent’ as the experiments progressed) there was no evidence that these effects differed across simulated dual-view and simulated interactive searches. The results are discussed in relation to benefits of interactive search for supporting target detection by airport screeners

    Does testosterone affect the normal menstrual cycle? Clin Endocrinol (Oxf

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    SUMMARY In order to throw further light on the role of androgens in the aetiology of the polycystic ovary syndrome (PCO) we have examined the effect of artificially increasing serum testosterone levels on menstrual function in a group of ovulating women. Six women were studied who had either severe premenstrual syndrome or loss of libido for which they were treated with 100 mg testosterone by S.C. implantation. All had regular menstrual cycles. For I month before implantation serum LH, FSH, oestradiol (Ez), progesterone and testosterone were measured three times per week. All women showed normal cyclical variation of LH, FSH, E? and progesterone. Following implantation, three times weekly blood samples were taken during the first and third cycles. No patient had any disturbance of menstrual pattern. All continued to show cyclical changes of LH, FSH, E? and progesterone. Serum E2 and progesterone were lower but not significantly so in the luteal phase of the treated cycles. This was despite a mean serum testosterone which rose from 1.3 to 7-1 nmol/l at the end of the third week following implantation and to 4.1 nmol/l at the end of the third month. Sex hormone binding globulin levels fell as expected by 18.5% during the first cycle. The lack of significant effect of a markedly elevated serum testosterone level on cyclical hormone changes is indirect evidence that in PCO the primary cause of the menstrual disturbance is not excessive production of ovarian or adrenal testosterone
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