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Biomedical subjects

J Torres

Publications and source records attributed to J Torres.

At least 217 records · Page 12Linked to original sources
PubMed1980

Morphological changes in strains of Aspergillus flavus Link ex Fries and Aspergillus parasiticus Speare related with aflatoxin production.

Two strains of Aspergillus flavus Link ex Fr. and two strains of A. parasiticus Speare were cultured on crushed moist wheat (Triticum durum var. Pané no. 257) for aflatoxin production studies in correlation with morphological changes. The toxicogenic strains were adapted to the substratum by means of successive transfers at regular intervals (72 h.) The amount aflatoxins synthesized by the toxicogenic strains decreased gradually after succesive subculturing. The decrease was accompanied by marked morphological changes. One of the strains studied, A. flavus NRRL 3251, lost completely the capacity of aflatoxin synthesis after several subcultures, presenting at the same time strong morphological variations. A. flavus CBS 120.62 also lost its toxicogenicity after six subcultures.

Aflatoxins↗
PubMed1980

A stereological analysis of developing egg chambers in the honeybee queen, Apis mellifera.

A polytrophic ovariole of the queen honeybee, Apis mellifera, is composed of a linear series of increasingly mature egg chambers, each consisting of an oocyte, an interconnected cluster of nurse cells, and a covering layer of follicle cells. This study describes changes in the volume of each of these components, as a function of the position of the egg chamber in the ovariole. An oocyte increases in volume from approximately 8.9 x 10(3) micrometers3 to approximately 9.6 x 10(6) micrometers3 over an average series of 20 egg chambers.

Animals↗
PubMed1980

Cell cycle kinetics of uninfected and feline leukemia virus-infected canine lymphoma cell lines: effects of methotrexate treatment.

The cell cycle kinetics of uninfected and feline leukemia virus-infected canine lymphoma cell lines were determined by autoradiography (PLM method) as follows: DT-5: generation time (TC), 15.2 h; pre-synthetic gap phase (TG1), 3.2 h; DNA-synthetic phase (TS), 8.2 h; post-synthetic gap ph se (TG2), 3.3 h; visible mitotic phase (TM), 0.5 h. 11028: TC, 13.6 h; TG1, 1.9 h; TS, 7.7 h; TG2, 3.4 h; TM, 0.6 h. 11028+FeLV (11028 productively infected with feline leukemia virus): TC, 11.2 h; TG1, 0.2 h; TS, 8.3 h; TG2, 2.1 h; TM, 0.6 h. Exposure of the lymphoma cell lines to methotrexate (MTX) in vitro produces dose-related increases in cellular volume, associated with reductions in cellular proliferation. The relative sensitivities of these cell lines to MTX, measured by the ID50 MTX concentrations for DT-5, 11028, and 11028+FeLV are 118 nM, 122 nM, and 28 nM respectively. The cell kinetic effects of the ID50 MTX concentrations added to cultures of lymphoma cells pulse-labeled with tritiated thymidine are an approximately 2-h prolongation of TC, attributable to a lengthening of TS, with other cell cycle phases not significantly altered. These cell lines are highly tumorigenic when transplanted into the cheek pouches of immunosuppressed hamsters, with inocula of 10(4) cells producing rapidly growing, well vascularized tumors.

Animals↗
PubMed1979

Single and divided doses of penbutolol.

Penbutolol, a nonselective beta-adrenoreceptor antagonist, induced reduction of exercise-induced heartbeats for at least 24 hr after a single 40-mg oral dose, and was equipotent with respect to a 2 X 20-mg regimen over the same period. Ingestion for 7 days did not influence the pharmacodynamics or pharmacokinetics of penbutolol, and there was no cumulation of drug in serum. A relationship was found between the logarithms of measurable serum concentrations of penbutolol and the percentage reduction of total heartbeats. Absorption of oral penbutolol appeared to be reduced when administered in the evening. Since beta-adrenoceptor activity was relatively unchanged between 13 and 24 hr after a single 40-mg dose of penbutolol, there is a possibility that an active metabolite or metabolites may contribute to prolonged duration of action.

Adult↗
PubMed1978

Analysis of intestinal cell proliferation after guanethidine-induced sympathectomy. I. Stathmokinetic, labelling index, mitotic index, and cellular migration studies.

Guanethidine-induced sympathectomy in the rat during the neonatal period (injection of 20 microgram/g body weight every 48 h from day of birth until day 14) produces an absolute reduction in the number of sympathetic ganglion cells, but no significant alteration of body weight. Superior cervical ganglia show 79.8% fewer cell bodies at 15 days and 92.3% at 45 days; coeliac ganglia exhibit an 81.0% reduction at 15 days and 89.6% at 45 days in guanethidine-treated rats as compared to normal controls. The sympathetic ganglion cells that remain after treatment have an abnormal morphological appearance with distended mitochondria and depletion of endoplasmic reticulum. Sympathectomy produces a prolongation of the generation cycle time (Tc) as measured by the colchicine-induced mitotic arrest technique, and a decrease in labelling, mitotic, and migration indices. In addition, sympathectomy suppresses the amplitude of the circadian rhythm in mitotic activity. The general suppression of this activity in the intestinal epithelium is more pronounced in the jejunum and ileum than in the duodenum. Variation in the effectiveness of sympathectomy on the inhibition of intestinal cell proliferation may be related to segmental differences in cell proliferation, to segmental differences in innervation, and/or to segmental variation in the effectiveness of guanethidine.

Animals↗
PubMed1978

Plasma cortisol levels in normal volunteers receiving either betamethasone valerate or desoximetasone by topical application.

Desoximetasone (Topisolon; Hoechst), a new topical steroid, and betamethasone 17-valerate were compared with respect to their effects on hypothalamic-pituitary-adrenal function as evidenced by plasma cortisol concentrations. Three grams of each test preparation were applied daily for 21 days to intact skin of the ventral aspects of alternate forearms of 15 normal volunteers. Five received betamethasone 17-valerate 0.1%, 5 desoximetasone 0.05%, and 5 desoximetasone 0.25%. Plasma cortisol levels were determined before and after the initial applications on days 1, 3, 10, 17, 22, 24 and 28. These values were compared with the mean control values by analysis of covariance. There was no significant difference in plasma cortisol levels. The value of performing similar studies on larger skin areas and with larger doses is discussed.

Administration, Topical↗
PubMed1978

Prevalence of epilepsy in Bogota, Colombia.

A combined epidemiologic, clinical, and electroencephalographic study of epilepsy was undertaken in Bogota by the Neurological Institute of Colombia, the Colombian Institute of Health, and the Department of Health of the City of Bogota. The prevalence of epilepsy on December 31, 1974, was 19.5 per 1,000, the highest rate for general populations reported in the literature. The prevalence was significantly higher for females than for males, 22.9 per 1,000 compared with 15.5 per 1,000.

Adolescent↗
PubMed1977

Response of plasma aldosterone to orthostatism during follicular and luteal phases of the normal menstrual cycle.

The responses of plasma aldosterone (A) and plasma renin activity (PRA) to orthostatism have been evaluated in 47 women during the follicular and/or luteal phase of the menstrual cycle. Three postmenopausal women and 51 men were also studied for control. Fourteen cycling women and 11 men were studied on a low sodium diet (20 mEq/day) while the rest of the subjects were on normal sodium intake. In addition, 18 women (including those postmenopausal) and 17 men were studied after intravenous administration of 20 mg frusemide. The response of A to orthostatism in women during luteal phase on normal sodium diet with or without frusemide was much greater than in men or women during follicular phase (p less than 0.01) or menopuase (p less than 0.05). However, no differences between groups could be observed in A response while on a low sodium diet. PRA response was similar during follicular of luteal phase fo the cycle as well as in men either on low or normal sodium intake with or without frusemide.

Adult↗
PubMed1976

A method of Pomeroy tubal ligation reanastomosis.

A method of reanastomosis of the uterine tube after Pomeroy tubal ligation is presented. The pregnancy rate was 69%. The viable birth rate was 38%, with 1 ectopic pregnancy, 2 patients pregnant, and 1 patient lost to followup at the time of this report.

Female↗
PubMed1976

Porfiromycin in the management of epidermoid and transitional cell cancer: a phase II study.

Porifiromycin has been tested in many groups of patients over the past several years (1-7). This report is an analysis of greater than 100 patients with epidermoid and urinary tract transitional cell carcinomas treated with this agent. A review of these data and the available literature on this agent shows that porfiromycin offers definite usefulness in disseminated squamous cell carcinomas of the cervix, and definite but lesser effectiveness in epidermoid carcinomas of the lung, the head and neck region, and other sites. Responsiveness was also demonstrated in transitional cell carcinomas of the urinary tract. Toxicity was tolerable and consisted primarily of myelosuppression and local skin necrosis in sites where extravasation had occurred.

Carcinoma, Squamous Cell↗