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B Chávez Lara

Publications and source records attributed to B Chávez Lara.

15 recordsLinked to original sources
PubMed1997

Estrogenic effects of p-hydroxybenzoic acid in CD1 mice.

Xenobiotic estrogens in the environment or diet have received much attention as a possible source of certain hormonal disease states in human and wildlife. Therefore, the detection of estrogenic activity of any substance, especially those related to the food industry, is important. The estrogenic activity of p-hydroxybenzoic acid (PHBA), a compound related to a commonly used group of preservatives in food, cosmetic, and pharmaceutical preparations, was evaluated with immature and adult ovariectomized female mice (CD1) using two well-known bioassays. Subcutaneous administrations (s.c.) of different doses of PHBA were compared with estradiol (E2), and their effects on vaginal cornification and uterotrophic activities were evaluated. Different groups of animals were treated s.c. daily for 3 days with vehicle (corn oil, 0.3 ml/100 g), E2 (1 microgram/100 g), and PHBA (0.5, 5, 50, and 500 micrograms/100 g). Four days after treatment, PHBA produced a dose-dependent response on vaginal cornification and uterotrophic activity in both immature and adult ovariectomized mice. The relative uterotrophic potency of PHBA (500 micrograms/100 g) to E2 (1 microgram/100 g) was 0.0011 in immature mice and 0.0018 in ovariectomized animals.

Animals↗
PubMedDate not supplied

[Dopamine in essential arterial hypertension: excretion of its metabolite homovanillic acid].

The results obtained in a group of 66 hypertensive patients in which the AHV values were 5.7 plus and minus 0.4 mM/24 hrs., were reported. These values were compared to those obtained in 42 healthy subjects: 7.0 plus and minus 0.5 mM/24 hrs. The difference was statistically significant P less than 0.05. The values of excretion of urinary dopamine in both groups were also presented. A value of 225.7 plus and minus 13.0 mug/24 hrs. was obtained for the hypertensives, while the value for the healthy groups was 361.2 plus and minus 16.5. The statistical study in this case showed a high significance p smaller or less than 0.001. There were no changes in the levels of adrenaline and noradrenaline nor in the metabolite of these two amines, that is, AVM.

Adolescent↗
PubMedDate not supplied

[Catecholamine-producing tumors].

We report 93 patients with catecholamine producing tumors that were analyzed at the Hormone Laboratory of the Institute of Cardiology. They are 75 pheochromocytoma patients and 18 children with neuroblastoma. Fluorimetric methods were used to measure urinary and plasma catecholamines on neuroblastoma and pheochromocytoma patients. Dopamine high excretion (mean value 2889 micrograms/24 hs), was constantly observed in the neuroblastoma children as were adrenaline and noradrenaline in the benign and malignant pheochromocytoma patients. The mean values for the malignant tumours were 53 for adrenaline and 1436 micrograms/24 hs for noradrenaline. Structural and biochemical differences of the catecholamine producing tumours are reflected on the clinical manifestations which are observed in the patients bearing such neoplasms.

Adolescent↗
PubMedDate not supplied

[Chemical and hematological changes in pheochromocytoma].

We report the laboratory findings from studies carried out on 37 pheochromocytoma patients; (20 males and 17 females whose age ranged from 11 to 55 years). Among the parameters measured, fasting hyperglycemia was one of the alterations most frequently encountered (59%), the difference with the normal values was highly significant (p less than 0.001). The levels found for the other parameters measured were also elevated in some cases and the difference between them and the normal values was statistically significant, the assays included were serum cholesterol and creatinine, haemoglobin, hematocrit and white blood cell and platelet counts. The response to the oral glucose load was normal in 9 patients, 6 showed a diabetic curve and 2 had a glucose intolerance response. Data from our observations and from the literature shows that these alterations may be a source of erroneous diagnosis, mainly in cases where symptoms are atypical or infrequent such as fever of unknown etiology, shock and others. Therefore recognizing these abnormalities as a sign of pheochromocytoma is very important both from the diagnostic and therapeutic points of view.

Abdominal Neoplasms↗
PubMedDate not supplied

[Pheochromocytoma and catecholamines. Experience in 63 cases studied for 25 years].

The usefulness of fluorimetric techniques in the diagnosis of pheochromocytoma was investigated. In the 63 cases studied during 25 years by measuring simultaneously various aminergic parameters, including plasma catecholamines and urinary adrenaline (A), noradrenaline (N) and vanilmandelic acid (VMA), we were able to establish the diagnosis of pheochromocytoma in all cases. Adrenaline excretion was found to be higher in patients with tumors located on the adrenal region, whereas N excretion was predominantly increased in patients with extra-adrenal tumors. In patients having tumors smaller than 50 g, A + N excretion was higher and VMA was lower than in those whose tumors were heavier; therefore in cases with small tumors the ratio VMA/A + N was lower than in those with larger tumors. It is concluded that simultaneous measurements of PC, A, N and VMA allow the diagnosis to be made in the most patients with this tumor. On the other hand, the predominant increase in A excretion is suggestive of adrenal pheochromocytoma.

Adolescent↗
PubMedDate not supplied

[Plasma catecholamines; values in normal subjects and its use the localization of pheochromocytoma].

The results of plasma catacholamines obtained from a group of 79 healthy subjects, 35 females and 44 males varied from 2.4 to 26.5 ng/100 ml of plasma. There was no statistical difference due to sex or age. The value of plasma catacholamines in blood samples taken from catheterizations of inferior vena cava in patients with Pheochromocytoma was useful in the localization of the neoplasia in 4 cases which were studied. The maximum values coincide with the side or site of the localization of the neoplasia in the 4 cases. The clinical diagnosis of pheochromocytoma was suspected in the other three cases which were not catheterized and in those in which the clinical suspicion was evident. One of these cases was operated on and the tumor was found in the right adrenal gland. The other two patients have refused catheterization as well as the exploratory surgery. One of these is controlled with adequate medication while the other has refused all treatment.

Adolescent↗