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Biomedical subjects

M Dennis

Publications and source records attributed to M Dennis.

15 recordsLinked to original sources
PubMed1979

Hemispherectomy for Sturge-Weber syndrome.

Patients with Sturge-Weber disease who have the onset of seizures in infancy invariably face a progressively downhill course which leaves them severely hemiplegic, demented and usually institutionalized because of uncontrolled seizures. During the past 12 years, we have carried out 6 hemispherectomies in infants under 1 year of age who presented with seizures and Sturge-Weber disease. The results have been gratifying. Seizures have stopped, hemipareses have been minimal and intellectual development has been good.

Angiomatosis↗
PubMed1977

Endoscopic laser treatment. II. Comparison of the efficacy of high and low power photocoagulation in control of severely bleeding experimental ulcers in dogs.

The coagulative efficacy of a "high power" argon laser which delivers 6.5 +/- 1.0 w was compared to that of a "low power" argon laser which delivers 1.0 +/- 0.1 w. The wave-guide angle of divergence was 8 degrees. For the high power laser, the distance between the wave-guide tip and the mucosa varied from 1.0 to 1.5 cm with a delivered power density range of 160 to 487 w per cm2. For the low power laser, the distance between the tip and mucosa varied from 0.7 to 1.3 cm with a power density of 35 to 146 w per cm2. Group A consisted of acute experiments in 6 heparinized dogs in which 51 standard-sized acute gastric ulcers extending into the submucosa were made at laparotomy via a large gastrotomy. Ulcer bleeding rates were quantified into three categories of severity. Within each category, ulcers were randomized to high power, low power, or untreated control. All 19 low power-treated ulcers and 16 untreated controls continued bleeding; 13 of 16 high power-treated ulcers stopped bleeding completely. Representative ulcers were examined histologically. Group B consisted of chronic experiments on 31 ulcers in 7 unheparinized dogs. These ulcers were either treated with high power or left as untreated controls. Dogs were killed and the ulcers were examined histologically at 7, 14, and 28 days. Only rarely did the laser injury penetrate into the muscularis externa. There were no perforations. By 14 days, all lesions were covered with normal surface epithelium. These data encourage further development of congruent to 7.0 w argon laser photocoagulation for eventual clinical use in man.

Animals↗
PubMed1976

Lymphatic absorption and metabolism of orally administered testosterone undecanoate in man.

[3H]-testosterone undecanoate ([3H]TU) was administered orally to 4 patients with a thoracic duct catheter after neck dissection surgery. Appearance of radioactivity in lymph, plasma and urine was measured at different times. Metabolites of TU in these fluids were investigated. Peak levels of radioactivity appeared simultaneously in lymph and plasma (2.5-5 h after administration) while the excretion in urine was highest approximately 2 h after the plasma and lymph peak. The main compounds appearing in the lymph were TU and 5alpha-dihydrotestosterone undecanoate (5alpha-DHTU), but 5beta-DHTU could not be detected. In plasma almost all metabolites were probably conjugated. During the first 24 h approximately 40% of the administered radioactivity was excreted in the urine. The total amount of radioactivity excreted in the urine during the first week was 45-48%. The predominant urinary metabolites were testosterone- and androsterone-glucuronide. The results indicate that TU is metabolized partly in the intestinal wall. The remaining TU and newly-formed 5alpha-DHTU, at least partly, are absorbed via the lymphatic system.

Administration, Oral↗
PubMed1976

Comparison between the binding of 19-nortestosterone, 5alpha-dihydrotestosterone and testosterone in rat prostate and bulbocavernosus/levator ani muscle.

Specific binding of (3H)19-nortestosterone in the 100000 g cytosol of the rat bulbocavernosus/levator ani muscle (BCLA) and prostate was demonstrated by agargel electrophoresis at low temperature and compared qualitatively and quantitatively with the binding of tritiated testosterone and 5alpha-dihydrotestosterone (5alpha-DHT). Both tissues showed a greater binding affinity for 5alpha-DHT than for 19-nortestosterone, with testosterone binding the least well of the three. The relative binding affinities in the BCLA and prostate were: 19-nortestosterone:testosterone=1-4, 1.-nortestosterone: 5alpha-DHT = 0.7 The differences were statistically significant (P less than 0-02). The concentrations of receptor sites for 5alpha-DHT were 171 +/- 20 (S.D.) fmol/mg prostatic cytosol protein and 24 +/- 4 (S.D.) fmol/mg BCLA cytosol protein. The in-vitro metabolism of the three steroids in both tissues was aldo investigated by thin-layer chromatography. After incubating for 2 h at 0 degrees C the prostate was shown to reduce 26% of the 5alpha-DHT to androstanediols whilst the BCLA showed a 5% conversion. Testosterone was converted by the prostate to 5alpha-DHT (10%) and the androstanediols (6%) whilst the BCLA showed little activity in this respect. Comparing these in-vitro data with in-vivo findings from the literature, in both organs there is a positive correlation of the extent of binding in vitro to the stimulation of growth in vivo, bearing in mind that testosterone is metabolized to 5alpha-DHT in the prostate whilst in the BCLA, 5alpha-reductase is essentially absent.

Animals↗
PubMed1975

In vivo uptake and metabolism of 3-h-5alpha-androstane-3alpha,17beta-diol and of 3-h-5alpha-androstane-3beta,17beta-diol by human prostatic hypertrophy.

Tritiated 5alpha-androstane-3alpha,17beta-diol (3alpha-diol) and 5alpha-androstane-3beta,17beta-diol (3beta-diol) respectively were administered to patients with benign prostatic hypertrophy (bph) undergoing prostatectomy. In prostate and skeletal muscle homogenates and in plasma the total radioactivity content as well as the formation of metabolites were measured. Histological examination of each ectomized prostate was performed to evaluate the cellular composition of the tissue. After 3alpha-diol injection, a higher uptake of radioactivity in the prostate was obtained than after 3beta-diol. Within 30 min the 3alpha-isomer was very efficiently converted to 5alpha-DHT, while most of the 3beta-isomer remained unchanged. There was, however, also after administration of the 3beta-diol a substantial biconversion to 5alpha-DHT as has been confirmed by recrystallization to constant specific radioactivity. Only after 3beta-diol epiandrosterone was detected in small but significant amounts. 3alpha-diol administration resulted in distinct concentrations of 3beta-diol, whereas the conversion of 3beta-diol to the 3alpha-isomer was insignificant. When comparing the histological composition of the prostatic tissue with the accumulation of radioactivity and the formation of metabolites only a weak correlation between glandular structure and radioactivity uptake after 3alpha-diol administration could be revealed.

Aged↗