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F López

Publications and source records attributed to F López.

At least 109 records · Page 6Linked to original sources
PubMed1990

Morphometric data concerning the great arterial trunks and their branches.

In a total of 496 fetuses and newborns ranging in body weight from 60 to 5000 g, we performed a morphometric study of the vascular complex, that is the orifices of the great arterial trunks, ascending aorta, aortic arch, vessels branching from the aortic arch, the aortic isthmus, descending aorta, pulmonary trunk, orifices of the pulmonary arteries and arterial duct. In all, 17 different parameters were measured in each specimen, using several new parameters in addition to the measurements classically used in the aortic isthmus, arterial duct and pulmonary trunk. Anatomo-geometric models of these structures were developed, and stereometric formulas used to calculate the real volumes of the aortic isthmus, arterial duct and pulmonary trunk. The variations in the correlations between two measurable characteristics, that is, body weight and each of the morphometric parameters were analyzed, and the minimum, normal and maximum patterns of normality for each parameter were obtained with regression equations. The results show that the volume of the aortic isthmus increases by 0.03 ml for each millilitre increase in left ventricular volume. The isthmic volume increases by 0.32 ml for each millilitre increase in volume of the arterial duct and the volume of the pulmonary trunk increases by 6.4 ml for each increase of 1 millilitre in the volume of the aortic isthmus. The inner circumference of the aortic isthmus is greater than that of the arterial duct, whereas the former vessel is always shorter than the latter. We believe that these morphological data, when appropriately interpreted, have immediate clinical and surgical applications in the treatment of fetal and perinatal cardiovascular disorders.

Aorta↗
PubMed1990

Effect of clonidine, nimodipine and diltiazem on the in vitro opioid withdrawal response in the guinea-pig ileum.

1. The effects of clonidine, nimodipine and diltiazem, on the in vitro withdrawal contracture induced by naloxone in the guinea-pig ileum obtained from morphine-dependent animals, were evaluated. 2. The in vitro incubation with clonidine (0.01, 0.1 and 1 microM), diltiazem (0.25, 0.1 and 1 microns) or nimodipine (0.05, 0.1 and 1 microns) reduced significantly the force of the contracture induced by naloxone in the morphine-dependent guinea-pig ileum. 3. The intraperitoneal administration of clonidine (0.3 mg kg-1), nimodipine (5 mg kg-1) or diltiazem (20 mg kg-1) reduced the contractile response induced by naloxone in the morphine-dependent guinea-pig ileum. 4. It is concluded that at least part of the effect of clonidine, nimodipine and diltiazem on withdrawal contractures is mediated via a peripheral, rather than a central site of action. Even though, the mechanism responsible for the effect of the calcium channel blockers differs from that of alpha 2-adrenoceptor agonists, all of the drugs tested prevented the contracture induced by naloxone in morphine-dependent guinea-pig ileum.

Animals↗
PubMed1990

[Evaluation of a tuberculosis prevention and control program (1987-1989)].

Tuberculosis continues to be an important health problem. A tuberculosis prevention and control program was begun in 1989 in Ciutat Badia, introducing the inclusion of those who had been in close contact with infected subjects. In the two years of the study, a total of 1,548 tuberculin tests was performed, 518 of which were positive 33%). Prevalence of tubercular infection in the study population, was 13.95%. Ages ranged from 14 to 20 years. We detected 20 cases of pulmonary tuberculosis and were able to study 91% of those who had been in close contact with the subjects in question. Three of these were detected in the latter study, and two by contact with tubercular infection. We prescribed a total of 180 chemoprophylaxes (47 primary and 133 secondary) with compliance of 60% and 71% respectively. We believe that chemoprophylaxis plays an important role in the prevention and control of tuberculosis in primary care.

Adolescent↗
PubMed1990

[Diverticular disease of the colon, the indications for and results of elective surgical treatment].

Precise criteria were prospectively used to indicate surgery in patients with diverticular disease of the colon: a) anatomical deformity of the sigmoid (ADS), including stenosis and fistulae with presence of contrast media extraluminally; b) recurrent acute diverticulitis (RAD); c) prior diverticulitis with perforation (DP) and d) recurrent GI bleeding (GIB). 42 patients were operated on according to these criteria, from 1978 to 1988, 26 males and 16 females, with a mean age of 61 years (range 31 to 93). ADS was the indication in 22 patients (52%), with fistulae present in 9. RAD was the indication in 16 patients (37%), DP in 9 patients (21%) and GIB in 5%. All patients were submitted to either ample sigmoid resection or left hemicolectomy. All patients were followed, with a mean of 43 months for the series. Only 1 patient died after surgery from pulmonary embolism. Late clinical evaluation revealed absence of preoperative symptoms and signs. We feel that surgical treatment of diverticular disease of the colon is warranted with the criteria described, with good immediate and longterm results.

Adult↗
PubMed1990

[Radiation enteritis: the results of surgical treatment].

We reviewed the results of surgical therapy for radiation enteropathy in 18 consecutive patients. Fifteen (83%) were females and the age ranged from 31 to 81 years old. The indication for radiotherapy was cancer of the cervix in 10 patients (56). The mean radiation dose was 5190 rads (range 4000 to 7000). Of 23 radiation lesions, 12 (52%) were located in the ileon, 10 in the rectum and 1 in the sigmoid. Fibrosis and stenosis was the most frequent lesion (70%) followed by fistulae (22%) and proctitis in 2 patients. Resection or derivation was the surgical treatment employed in 22 of the 23 lesions. For lesions of the ileon, we performed resection and anastomosis in 7 patients and derivation in 5. For rectal lesions we performed resection, endoanal descent and colo-anal anastomosis in 7 patients anterior resection in 2 and colostomy in 1. Complications were observed in 5 patients (28%) and 1 patient died (5%). After a mean follow up of 56 months, 5 patients have died from recurrence of the original neoplastic lesions. We feel that surgical treatment allows improvement in quality of life of patients with radiation enteropathy.

Adult↗
PubMed1989

Luteinizing-hormone-mediated precocious puberty induced in female rats by a prepuberal pituitary graft.

The present study analyzes the mechanism of precocious puberty induced in female rats after a 'young' pituitary graft (obtained from 21-day-old animals). For this purpose, the following experiments have been performed: (1) female rats were grafted or sham-operated on day 21 with a littermate's pituitary the follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol plasma levels as well as the ovarian, uterine and adrenal weights were determined at different times after the graft; (2) female rats grafted or sham-operated on day 21 were treated with 0.2 ml of LH antiserum (LHAS) or the same volume of a normal horse serum (NHS); (3) female rats were injected on day 1 of life with 0.1 mg of estradiol benzoate or olive oil. Groups of these animals were decapitated daily between days 6 and 21 in order to measure gonadotropins and prolactin (PRL) pituitary content. Since on day 21 estrogenized females showed decreased gonadotropin content and normal PRL content, females in experiment 4 were grafted on day 21 with pituitaries obtained from control or neonatally estrogenized female rats. The results obtained showed that FSH, LH and estradiol plasma levels as well as ovarian and uterine weights increased after pituitary grafts. LHAS blocked the precocious puberty induced by the pituitary graft, and pituitaries obtained from neonatally estrogenized female rats were unable to modify the occurrence of puberty when grafted. In conclusion, this work evidences that precocious puberty induced by 'young' pituitary grafts was mediated by the increase in LH secretion from the graft.

Adrenal Glands↗
PubMed1989

[Colorectal cancer: follow-up after curative resection].

From Jan 1978 to Dec 1984, 128 patients had a curative resection of colorectal carcinoma. A program for early detection and surgical correction of recurrences was initiated in 88 patients with a mean age of 61 years (range 24 to 85). Seventy two patients complied with the program involving clinical examination, chest X-ray, alkaline phosphatase and CEA determinations and endoscopy at 6 month intervals. Mean follow up was 36 months (range 6 to 60). A total of 28 recurrences (32%) were detected: 4 local, 17 distant and 7 local and distant. Recurrences occurred in 46% of grade C, 19% of grade B and 0% of grade A lesions. Sixty eight% of recurrences were detected within 12 months and 93% within 36 months after surgery. Recurrences were detected by clinical examination in 71% of cases. CEA determination was sensitive (81% and specific (92%) for detection of recurrences in the remaining patients. Four patients (14%) were reoperated on with a survival of 3 to 26 months, all dying from disseminated disease. We conclude that this program did not help to improve the 5 year survival rate of colorectal carcinoma submitted to curative resection. CEA determination may be indicated at 2 month intervals during the period of increased recurrence risk.

Adult↗
PubMed1988

Lipoprotein structural abnormalities in chronic renal failure with and without hemodialysis.

Nine patients with chronic renal failure in maintenance hemodialysis (CRF-HD) and nine without hemodialysis (CRF) showed similar modifications in the structure and composition of VLDL and LDL isolated by density gradient centrifugation as compared to normal controls. In very low density lipoproteins (VLDL), the ratios of triglycerides to protein and of cholesterol to protein were strongly correlated. All patients, independently of their cholesterol and triglyceride levels, presented a "beta-VLDL" caused by an increment in the isoelectric point of the particles in the density range 1.006-1.019 g/ml. This was probably due to the augmented proportion of apoB in them and is not associated with the E2 phenotype. The results indicate that the structural modifications of VLDL and low density lipoprotein (LDL), present in chronic renal failure, are not changed by maintenance hemodialysis and that they are not necessarily associated with hyperlipidemia.

Adult↗
PubMed1987

Possible direct effect of serotonin on pituitary prolactin secretion: in vivo and in vitro studies.

In this work we analyze the possibility of serotonin (5-HT)-releasing prolactin (PRL) through a direct action at the pituitary level. 5-HT (2 mg/kg i.v.) stimulates PRL secretion in hypophysectomized autotransplanted animals (HAG) significantly and this effect was not influenced by pretreatment with the dopaminergic antagonist domperidone. In perifused pituitaries, 5-HT administration (0.01, 0.1 and 1 microM for 90 min, or 1, 10, 100 microM for 15 min) was ineffective in stimulating PRL release. In pituitaries obtained from animals previously treated with the neurotoxic 5,7-dihydroxytryptamine (5,7-DHT) or vehicle and incubated in the presence of 5-HT (2.5, 5 and 10 microM), no response in PRL secretion was observed. These results suggested that 5-HT does not release PRL through a direct pituitary action, and that the effect observed in HAG animals could be mediated through the release of a PRL-releasing factor after 5-HT administration.

5,7-Dihydroxytryptamine↗
PubMed1986

Two possible mechanisms for precocious puberty induced in female rats by pituitary grafts.

Many reports indicate that prolactin has a role in puberty occurrence. The present study was developed to evaluate the action of pituitary grafts on puberty. Female rats grafted on day 21 with "adult' (90 days old) or "young' (21 days old) pituitaries showed precocious vaginal opening and first estrus. The puberty advancement induced by "adult' transplants was due to an increase in plasma prolactin values and can be blocked by bromocriptine treatment. The puberty advancement induced by "young' transplants was not associated with increased prolactin levels and cannot be blocked by bromocriptine. These results suggest the existence of two possible mechanisms in precocious puberty induced by pituitary grafts: a prolactin-dependent one and another one not directly related with prolactin.

Adrenal Glands↗
PubMed1986

Pituitary regulation of corpus luteum progesterone secretion in cyclic rats.

Pituitary LH and PRL secretion during the early postovulatory period of the rat estrous cycle seem to affect the corpus luteum (CL) autonomy to secrete progesterone. Thus, while PRL would act luteotropically, LH would be luteolytic. To further investigate these facts, 4-day cyclic rats, treated with either 1 mg bromocriptine (CB) or 0.25 ml 70% ethanol (ETOH) at 1600 h on estrus, were injected with 0.5 ml of either an anti-LH serum (LHAS) or normal horse serum (NHS) at 0800 h on metestrus. Rats treated at 0800 h on metestrus with both, CB and LHAS, were also used. To verify through a different procedure the effect of LH and/or PRL deprivation in estrous cycle CL progesterone secretion, hypophysectomy (HYPOX) and sham HYPOX (SHAM) were done at 0800 h on metestrus in either CB- or ETOH-injected rats at 1600 h on estrus. Hypophysectomized rats at 1600 h on estrus were also used. Progesterone secretion was prolonged up to 0800 h on diestrus in those rats deprived of LH from 0800 h on metestrus (ETOH/LHAS, -/CB + LHAS, ETOH/HYPOX) compared with controls (ETOH/NHS, ETOH/SHAM). This luteotropic effect was absent in those rats lacking estrous afternoon PRL (CB/LHAS, CB/HYPOX, HYPOX/-). No effect on CL progesterone secretion was detected in those rats exclusively deprived of PRL on the afternoon of estrus (CB/NHS, CB/SHAM). These results suggest that in the absence of the protective effects of PRL secretion on the afternoon of estrus, rat CL become extremely sensitive to the luteolytic effects of early diestrous LH levels, and this results in 4-day estrous cycles.

Animals↗
PubMed1986

Serotonin stimulates GH secretion through a direct pituitary action: studies in hypophysectomized autografted animals and in perifused pituitaries.

To analyze a possible direct action of serotonin (5-hydroxytryptamine) at pituitary level in GH secretion, two experimental models were used: hypophysectomized autografted rats and perifused pituitaries. Adult male rats were hypophysectomized and their own pituitaries placed under the right kidney capsule. Ten days later an intra-atrial cannula was inserted. The next day, blood samples were obtained before and every 10 min during a 2 h period after the injection of saline or 5-hydroxytryptamine (1 or 2 mg/kg iv). Plasma volume was replaced with saline. Both doses of 5-hydroxytryptamine elicit a strong release of GH, the effect being dose-dependent. In pituitaries perifused with 5-hydroxytryptamine (100 microM during 115 min or 1, 10 and 100 microM during 15 min), a significant release of GH was also observed. These results suggested that 5-hydroxytryptamine may stimulate GH secretion through a direct pituitary action.

Animals↗
PubMed1986

Prolactin response to stress in neonatally estrogenized male rats.

Male Wistar rats were injected either 500 micrograms of estradiol benzoate or olive oil on their first day of life. Blood samples were obtained from the adult by decapitation, by decapitation after 15 min of restraint, by decapitation 10 min after a 5 min period of ether exposure or by jugular venipuncture after 60 s of ether exposure. Prolactin (PRL) plasma levels were measured by RIA. The PRL levels in samples obtained by decapitation were similar to control and estrogenized groups. A similar response to restraint was also found in both groups. Sixty s of exposure to ether stress stimulates PRL secretion only in the estrogenized males, this effect being blocked by treatment with Normifensine (5 mg/kg two hours prior to blood sampling). These results suggested that estrogenized male rats show greater sensitivity to acute ether stress than the controls, and that changes in the dopaminergic system could be involved in this response.

Animals↗
PubMed1986

Effect of indomethacin on the progesterone secretion of hysterectomized pseudopregnant rats.

The length of pseudopregnancy and the progesterone levels in rats pseudopregnant and hysterectomized on their 2nd day and injected daily with indomethacin (500 g/0.2 ml) from the 2nd to 10th day do not differ from those exhibited by oil treated rats. On the contrary, indomethacin treatment from 11th day on, results in both a lengthening of the diestrous phase and a delayed luteolysis. These findings point out to an extrauterine prostaglandin synthesis mechanism participating in the functional luteolysis in histerectomized pseudopregnant rats.

Animals↗