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Biomedical subjects

J Allen

Publications and source records attributed to J Allen.

At least 361 records · Page 20Linked to original sources
PubMed1985

Discordance of plasma DHEA-S, DHEA, and cortisol responses with various ACTH regimens.

The origin and time course of ACTH-stimulated adrenal androgens are controversial. Since previous protocols have used differing ACTH preparations and routes of administration, we sought to compare plasma DHEA and DHEA-S responses to four ACTH regimens. Fourteen young men underwent the following five three-day study periods: (1) placebo, (2) alpha 1-24 ACTH, 400 micrograms intravenously (IV); (3) alpha 1-39 ACTH, 400 micrograms intramuscularly (IM); (4) alpha 1-18 (D-Ser1, Lys17, Lys18) ACTH, 400 micrograms IM; and (5) alpha 1-18 ACTH, 400 micrograms IV. alpha 1-18 ACTH IV had the most potent and prolonged corticotropic effect, listing more than 24 hours, as measured by plasma cortisol, 17-OHCS, and cortisol secretion rates. alpha 1-39 ACTH and alpha 1-18 ACTH IM were corticotropic up to 12 hours, and alpha 1-24 ACTH IV was corticotropic only up to one hour. Plasma DHEA rose acutely at one hour with all of the ACTH regimens (P less than 0.05). This response was correlated with cortisol (r = 0.62, P less than 0.01) and reflected the relative corticotropic potency of each of the ACTH regimens. Plasma DHEA-S, on the other hand, did not rise acutely at one hour with any of the regimens. DHEA-S did rise at 12 hours with three of the ACTH regimens (alpha-1-24, alpha 1-39, alpha 1-18 IM), but this response was not synchronous with cortisol (r = 0.14, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1985

Repeat pituitary ablation for advanced prostatic cancer.

An elderly male patient with advanced prostatic adenocarcinoma, requiring increasing analgesia, underwent interstitial pituitary irradiation by implantation of yttrium-90. He was temporarily relieved of his pain. Assessment of his anterior pituitary function showed only partial ablation. He therefore underwent a second implantation. This achieved complete ablation, and only when this was achieved did he experience full and sustained pain relief. We recommend assessment of anterior pituitary function in patients treated by pituitary ablation for carcinoma of the prostate, and especially in those in whom the disease progresses after initial success response.

Adenocarcinoma↗
PubMed1985

Plasma prostaglandin F2 alpha and plasma 13,14-dihydro-15-keto-prostaglandin F2 alpha levels in women during induction of labor with i.v. infusion of prostaglandin F2 alpha in relation to uterine contractions.

The concentrations of plasma PGF2 alpha and its main metabolite, 13,14-dihydro-15-keto-PGF2 alpha (PGFM) were measured in serial samples of blood collected in 10 pregnant women at term who were given iv infusions of low doses of PGF2 alpha for induction of labor. Six other women served as controls and were given saline infusions. Uterine contractions began with a mean latency of 62 min in the PGF2 alpha infused women, in controls uterine activity remained unchanged. Plasma PGFM levels had increased significantly 30 min after PGF2 alpha infusion began, rising thereafter in a dose dependent manner. Plasma PGF2 alpha also rose reaching a steady state at 2 hours. No significant changes were observed in the controls. The 6-h infusion resulted in delivery in 5 of the 10 women, in the 5 others the cervical scores increased only by 1.25 points on the average and further treatment was needed to achieve delivery, although prostanoid levels rose to similar levels in all. The data show that when uterine contractions are induced by systemic PGF2 alpha, the levels of PGFM are significantly raised. In spontaneous labor uterine contractions begin long before plasma PGFM rises. Thus, if endogenous PGF2 alpha generation is involved in the initiation of uterine contractions during spontaneous labor, it must be synthetized in the myometrium at quantities too low to raise the levels of circulating PGFM.

Adult↗
PubMed1985

Serological evidence that chlamydiae and mycoplasmas are involved in infertility of women.

Women with a history of infertility for 2 or more years were examined by hysterosalpingography (HSG) and antibodies against Chlamydia trachomatis, Mycoplasma hominis and M. genitalium were measured by a microimmunofluorescence technique in sera obtained immediately before HSG. Of 45 women with abnormal HSG findings, 15 (33%) had antibodies to C. trachomatis and 16 (35.5%) to M. hominis. In contrast, of 61 women with normal HSG findings, only 8 (13%) and 7 (11.5%) had antibodies to these micro-organisms, respectively. Antibody against M. genitalium was found in 26 of the patients (20% abnormal HSG and 28% normal HSG), indicating the need for further investigation of the significance of this mycoplasma in female infertility. The present results do confirm, however, that C. trachomatis is an important cause of infertility in women and suggest strongly that M. hominis is implicated.

Adult↗
PubMed1984

Efficacy of ivermectin against gastrointestinal nematodes in dromedary camels.

The anthelmintic activity of ivermectin when administered orally and subcutaneously at a dosage of 0.2 mg/kg of body weight was evaluated in 4 trials involving 20 dromedary camels (Camelus dromedarius). Fecal egg counts were made on the day of treatment and at 2, 4, and 10 weeks after treatment. Trichostrongylid egg counts were reduced by a maximum of 100% when ivermectin was administered orally and by greater than 88% when given subcutaneously. Egg counts of Trichuris spp were reduced by greater than 85% with oral administration, but increased following subcutaneous treatment. No adverse local or systemic reactions were observed following treatment with ivermectin by either route.

Animals↗
PubMed1984

Are high schools adequately prepared to cope with serious rugby injuries?

A survey of 29 Western Cape high schools showed that 45% of schools had either no or an inappropriate stretcher available for the treatment of injured first-team rugby players, that 35% did not provide splints for the immobilization of limb fractures, and that 59% had no neck braces available. All schools provided field-side medical care for at home first-team rugby matches; in 21% of cases a doctor was always present and in a further 41% trained first-aid personnel were available, but 38% of the schools relied on rugby coaches. Furthermore only 62% of all first-team rugby coaches had some rudimentary training in the management of rugby injuries. Of the 38% of coaches who had received no training in first aid, fully 73% provided the sole field-side medical cover for rugby injuries. When questioned about the management of serious head and neck injuries, 93% of coaches were unaware that before a conscious player with a head injury is moved he must be asked whether or not his neck hurts, and 80% were unaware that an unconscious player should be treated as if he has an unstable neck injury. The implications of these findings are discussed.

Athletic Injuries↗
PubMed1984

Molecular mechanisms of gossypol action on lipid membranes.

Gossypol, an aldehyde extracted from cotton plants, produces both general toxic and antifertility effects in mammals. The cellular mechanisms by which gossypol exerts these effects are not understood. In this study, we have characterized the interactions of gossypol with lipid monolayer and bilayer membranes in order to assess if the drug acts by modifying the electrochemical properties of membranes. The charged form of gossypol binds to monolayers of different lipid compositions with apparent dissociation constants ranging from 0.7 to 2 microM. Binding of charged gossypol decreases the interfacial potential by 80-235 mV, the magnitude of this decrease being dependent upon the lipid composition. Gossypol also induces a conductance in phospholipid bilayer membranes. The relation between steady-state bilayer conductance versus gossypol concentration indicates that the current-carrying species is a single molecule of gossypol. The increase in bilayer conductance is accompanied by an increase in proton permeability. These changes induced by gossypol in model membranes can account for the mitochondrial uncoupling effects of this molecule and may be responsible for the inhibitory effects of gossypol on several membrane transport systems.

Animals↗
PubMed1984

Endorphins stimulate normal human peripheral blood lymphocyte natural killer activity.

Opioid peptides are present in peripheral blood, and may bind to human lymphocytes. In order to determine their influence on human lymphocytes we studied the effect of endogenous opioid peptides on human lymphocyte natural killer function. Beta-endorphin and several analogues (i.e., gamma-endorphin) are shown to enhance human peripheral blood natural killer function. The enhancement of natural killing by these opioid peptides was dose-dependent and naloxone (an opiate antagonist) reversible. In studying various analogues of beta-endorphin, beta-lipotropin and gamma-endorphin were approximately 3-5 times more effective at enhancing peripheral blood NK function than Leu-enkephalin and -endorphin. In addition, we observed that naloxone reversed human fibroblast interferon mediated enhancement of human blood lymphocyte natural killer function. These observations suggest that circulating endogenous opioid peptides may have a physiologic role in regulating human blood lymphocyte natural killing.

Dose-Response Relationship, Drug↗
PubMed1984

Determination of betaxolol, a new beta-blocker, by gas chromatography mass spectrometry: application to pharmacokinetic studies.

Betaxolol, a beta selective adrenoceptor antagonist recently approved for the treatment of hypertension, was determined by monitoring in chemical ionization mode with ammonia the [MH]+ ions of the trimethylsilyl derivatives of the drug and of its internal standard [2H5)betaxolol). Its pharmacokinetic profile obtained following administration of a 20 mg oral dose was characterized by a half-life of 22 h and a bioavailability of 85%. The main acid metabolite formed by elimination of the isopropylamino group may also be determined as the methyl TMS derivative but methylation with BF3-methanol should be used with caution since it may induce the opening of the cyclopropyl group. The routine electron capture determination procedure was compared to this mass spectrometric method and an excellent correlation was found (r = 0.9974). Both procedures have the same sensitivity (1 ng ml-1). Finally it was observed that under electron impact mode betaxolol trimethylsilyl side chain rearranged to lose TMS-O-CH=CH2; this elimination was confirmed by deuterium labelling studies.

Adrenergic beta-Antagonists↗
PubMed1984

Normal sister chromatid exchange levels in hospital sterilization employees exposed to ethylene oxide.

This study was undertaken to determine whether a specific group of hospital workers exposed to ethylene oxide (ETO) in sterilizing areas showed evidence of increased levels of sister chromatid exchange (SCE) formation. SCE frequencies were determined for 14 sterilizer workers and 14 matched controls. Time-weighted average (TWA) and peak ambient levels of ETO were measured in the sterilizing areas. Results indicated that all sterilizer workers were exposed to less than 5 parts per million TWA of ETO and that there were no statistically significant differences in SCE levels between sterilizer workers and controls. Smoking habits did appear to be associated with increased SCE levels. In this particular hospital setting no evidence of genetic effects stemming from employees' exposure to low levels of ETO was found.

Adult↗
PubMed1984

Effect of valproate on free plasma phenytoin concentrations.

The plasma protein binding of phenytoin was studied in nine epileptic patients before and during addition of sodium valproate to the drug therapy. The free phenytoin fraction in plasma was significantly greater during sodium valproate treatment. The mean free fraction rose from 0.135 +/- 0.019 (s.d.) to 0.182 +/- 0.030. Total plasma phenytoin concentration fell significantly from a range of 4.3-26.2 micrograms/ml to 3.4-19.8 micrograms/ml during sodium valproate treatment. Neither the free plasma concentration nor the saliva concentration of phenytoin was significantly altered by sodium valproate. No significant correlation was found between plasma valproic acid concentrations and the change in phenytoin binding. We conclude that valproic acid displaces phenytoin from plasma protein binding sites but does not inhibit its metabolism.

Adult↗
PubMed1984

Pelvic inflammatory disease after hysterosalpingography associated with Chlamydia trachomatis and Mycoplasma hominis.

A total of 116 women were referred for hysterosalpingography because of primary or secondary infertility. Chlamydia trachomatis was isolated from the cervix of four (3.4%) of the patients whereas Mycoplasma hominis was isolated from 39 (33.6%) of them. Four patients developed acute pelvic inflammatory disease after hysterosalpingography; two of them were chlamydia culture-positive and developed a significant chlamydial antibody response during the course of the disease. One of the other two patients, who developed upper genital-tract infection, was culture positive for M. hominis and developed a significant antibody response to this micro-organism. The results indicate that C. trachomatis should be sought in patients before hysterosalpingography and, if detected, appropriate antibiotic cover should be instituted before the procedure.

Adult↗
PubMed1984

5-Fluorouracil and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) followed by hydroxyurea, misonidazole, and irradiation for brain stem gliomas: a pilot study of the Brain Tumor Research Center and the Childrens Cancer Group.

Twenty-eight evaluable children with the diagnosis of brain stem glioma were treated with 5-fluorouracil and CCNU before posterior fossa irradiation (5500 rads); during irradiation, the children received hydroxyurea and misonidazole. The treatment was well tolerated, and minimal toxicity was produced. The median relapse-free survival was 32 weeks, and the median survival was 44 weeks. Analysis of covariates showed that, in patients between the ages of 2 and 19 years, survival was longest in the older children (P less than 0.02). Tumor histology, sex, extent of operation (if any), Karnofsky score, and radiation dose did not correlate with survival.

Adolescent↗
PubMed1984

Experience with an LHRH analogue in the management of relapsed progressive prostatic cancer.

Seventeen patients with advanced progressive prostatic cancer who had relapsed or failed to respond to conventional endocrine therapy with oestrogens, orchiectomy or antiandrogens were treated with the LHRH analogue, ICI 118630. No significant objective tumour responses were seen, though 11 of 15 patients who presented with symptomatic metastatic bone pain had rapid short-term pain relief. The lack of objective clinical response seen in this study indicates no justification for the use of LHRH analogues in this group of patients. Though a significant subjective response was seen there was no added advantage over regular analgesics.

Acid Phosphatase↗