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Biomedical subjects

C Mendoza

Publications and source records attributed to C Mendoza.

At least 109 records · Page 6Linked to original sources
PubMed1986

[Influence of body weight on gonadotrophins and steroid hormone levels in menstruating women].

In order to study the effect of obesity or underweight on gonadotropins and steroid hormone levels, serum concentrations of FSH, LH. Testosterone, Estradiol, Estrone, 17-OH-Progesterone and SHBG were measured by RIA in obese, underweight and control women, all menstruating in the follicular phase. Serum concentrations of all parameters measured did not differ significantly in the underweight and control groups. All obese women had higher levels of estrone than the control group, and only obese patients with a body mass index above 39 showed a lower SHBG level than that of the control group. The data suggest that the increased levels of estrone could play a role in the amenorrhea of obese women.

Androgens↗
PubMed1985

[Hypothalamo-hypophyseo-gonadal axis in individuals with chronic renal insufficiency subjected to hemodialysis].

The role of pituitary and sexual hormones in 21 patients with chronic renal failure (CRF) and related impotence and loss of libido who were being treated by hemodialysis and in 15 normal male controls has been studied. In both groups the serum levels of FSH, LH and TSH, PRL before and after injection of both LHRH and TRH were measured as well as the basal levels of Testosterone (T) and Estradiol (E2). The results show similar values for testosterone in both groups and statistically significant higher basal values for FSH, LH, TSH and PRL and lower basal values for E2 in CRF patients.

Adult↗
PubMed1985

Calcium metabolism in post-menopausal women.

To investigate some parameters involved in postmenopausal calcium metabolism we have measured FSH, LH, estradiol (E2), parathyroid hormone (PTH) calcitonin (CT), 25-hydroxy-vitamin D3 (25-OH-D3), total calcium (CaT) and ionic calcium (Ca++) serum levels in 20 healthy postmenopausal women and 20 premenopausal women. The results reported show that the decrease of estradiol levels are associated with a significant decrease in 25-OH-D3 serum levels, possibly as result of a lower concentration of vitamin D binding protein, which is extremely sensitive to changes in oestrogen levels. The PTH levels were similar in both groups studied, which might be explained together with increased ionic calcium levels in postmenopausal women, by decreased parathyroid sensitivity to the blocking action of Ca++.

Adult↗
PubMed1984

Role of the septum on LH, FSH and prolactin secretion in male rats.

Serum concentrations of luteinizing hormone (LH) follicle-stimulating hormone (FSH), prolactin (PRL) and testosterone were measured by radioimmunoassay in male Wistar rats: (a) Four days after a septal lesion (n = 19) and (b) Just following electrical stimulation of the septum (n = 15). Septal lesions induced a significant decrease in serum LH (16.37 +/- 2.01 vs. 30.27 +/- 2.08 ng/ml; p less than 0.001) and testosterone concentrations (0.53 +/- 0.05 vs. 1.01 +/- 0.14 ng/ml; p less than 0.02). No significant changes were observed for FSH or PRL levels. Electrical septal stimulation induced an increase in serum levels of LH (211.5 +/- 46.4 vs. 29.6 +/- 11.5 ng/ml; p less than 0.01) and FSH (703 +/- 83 vs. 378 +/- 57 ng/ml; p less than 0.01), without changes in PRL or testosterone concentrations. From these data we conclude that in male rats the septum may play a role in the mechanisms controlling gonadotropins release by the anterior pituitary gland.

Animals↗
PubMed1984

Effects of sulpiride on levels of FSH, LH and steroid hormones.

In order to study the effects of prolactin upon the gonadotrophins and steroid hormones, hyperprolactinaemia was induced by the administration of sulpiride. 12 men between the ages of 18 and 20 were given 3 capsules of 50 mg of sulpiride daily for a period of 15 days, and the following parameters being measured before and after the treatment: (prolactine, FSH, LH, testosterone, estradiol, ACTH and DHEA-S) by RIA, (cortisol) by fluorimetry and (etiocholanone, androsterone, pregnandiol, pregnantriol, pregnantriolone, 11-keto etiocholanone and 11-OH androsterone) by gas chromatography. Our results show that on termination of the treatment there was a significant rise in the prolactin and DHEA-S serum levels and a drop in the FSH serum levels but not of LH. In addition there was a marked increase in all the androgen levels studied, (etiocholanone, androsterone and 11-keto etiocholanone) with the exception of testosterone.

Adolescent↗
PubMed1980

Plasmid-determined resistance to fosfomycin in Serratia marcescens.

Multiple-antibiotic-resistant strains of Serratia marcescens isolated from hospitalized patients were examined for their ability to transfer antibiotic resistance to Escherichia coli by conjugation. Two different patterns of linked transferable resistance were found among the transconjugants. The first comprised resistance to carbenicillin, streptomycin, and fosfomycin; the second, and more common, pattern included resistance to carbenicillin, streptomycin, kanamycin, gentamicin, tetracycline, chloramphenicol, sulfonamide, and fosfomycin. The two types of transconjugant strains carried a single plasmid of either 57 or 97 megadaltons in size. Both of these plasmids are present in parental S. marcescens strains resistant to fosfomycin. The 57-megadalton plasmid was transformed into E. coli.

Anti-Bacterial Agents↗
PubMed1977

Saturation kinetics for steady-state pulmonary CO transfer.

Steady-state diffusing capacity of the lungs for carbon monoxide (DLCO) was measured in 13 anesthetized, paralyzed dogs ventilated at constant tidal volume and rate, using four different inspired CO levels (190, 600, 1,110, and 2,000 ppm). DLCO increased and reached a maximum as the inspired CO level was raised from 190 to 600 ppm. Further increases in inspired CO concentration were accompanied by a decrease in inspired CO concentration were accompanied by a decrease in DLCO. CO dead space and Pao2 remained constant at all inspired O2 levels. In some experiments a second set of measurements was made, the results of which were similar to those of the first set. The results cannot be explained by changes in CO back pressure, pulmonary capillary volume, or reaction rate of CO with hemoglobin, but can be explained if there is carrier-mediated CO transport in the alveolar capillary membrane.

Animals↗
PubMedDate not supplied

Bilateral mammary abscess and uveitis caused by Brucella melitensis--report of a case.

Soft tissue locations of Brucella are a rare finding. We report the isolation of Brucella melitensis from a suspected breast tumour of a woman who also showed signs of uveitis. Three weeks after surgical drainage and despite antimicrobial therapy a new abscess developed on the other breast whose culture also yielded Brucella. As observed, unusual localization of brucellosis without previous penetrating injury may be the only manifestation of chronic infection.

Abscess↗
PubMedDate not supplied

Electrocardiographic alterations during treatment of mucocutaneous leishmaniasis with meglumine antimoniate and allopurinol.

The electrocardiographic (ECG) changes in Bolivian patients with mucocutaneous leishmaniasis, treated with meglumine antimoniate and allopurinol, were evaluated. Electric changes due to the antimonial compound appeared in 45% of the patients, and consisted of repolarization alteration, principally affecting the T wave and the S-T segment. The changes disappeared within 2 months following the end of the antimonial treatment. In patients with associated Chagas disease and leishmaniasis, antimonial therapy did not aggravate the ECG changes characteristic of Chagasic cardiopathy.

Adolescent↗
PubMedDate not supplied

Estradiol modulates breast cancer cell apoptosis: a novel nongenomic steroid action relevant to carcinogenesis.

It is known that steroids can induce cell surface receptor aggregation followed by activation of receptor and nonreceptor tyrosine kinases. It has been shown recently that 17beta-estradiol (E2) can stimulate the Src/p21ras/mitogen-activated protein kinase pathway in breast cancer cells, and this effect is supposed to mediate the E2-induced stimulation of breast cancer cell proliferation, possibly via activation of the c-fos and c-jun early genes or of genes involved in cell cycle control. Here we demonstrate the existence of an alternative mechanism of the cancer-promoting effect of E2. Human breast cancer cells (MCF-7) were exposed to the known proapoptotic agent vitamin E succinate (VES), added alone or together with different concentrations of E2. E2 conjugated with bovine serum albumin (E2-BSA), which cannot cross the plasma membrane of living cells, was also used in some experiments to assess whether E2 acted on the cell surface or at intracellular receptors. Apoptosis was analyzed by fluorescence-activated cell sorting after cell staining with propidium iodide and FITC-labeled annexin V. E2 showed a concentration-dependent stimulatory effect on spontaneous apoptosis but inhibited the VES-induced apoptosis. However, effects produced by the same molar concentrations of E2 were different when the hormone was free and when it was used in the form of the E2-BSA conjugate. The effects of E2 and E2-BSA were sensitive to genistein, a tyrosine kinase inhibitor. These data show that E2 modulates apoptosis of breast cancer cells, probably acting both at the cell surface and inside the cells. Tyrosine phosphorylation is involved in the signaling pathways mediating this E2 effect.

Apoptosis↗
PubMedDate not supplied

Direct non-genomic effects of follicular steroids on maturing human oocytes: oestrogen versus androgen antagonism.

Previously published data have suggested that oestradiol exerts direct beneficial effects on human oocytes during in-vitro maturation and that these effects are at least partly due to a non-genomic action of the steroid at the oocyte surface. Here we provide evidence showing that a non-genomic effect of oestradiol is counteracted by androstenedione. In contrast to these results from in-vitro experiments, in which changes in steroid concentrations are abrupt and the non-genomic responses are rapid, the progressively changing follicular steroid concentrations which occur during in-vivo development may rather have permissive or restrictive effects on the events of spontaneous oocyte cytoplasmic maturation. The oocyte is particularly sensitive at the germinal vesicle stage of development to non-genomic steroid actions. Ovarian stimulation protocols should thus be adjusted so as to avoid androgen predominance at the mid-follicular phase. In patients in whom this condition cannot be met, in-vitro maturation of oocytes may be a solution.

Androgens↗
PubMedDate not supplied

Age-related differences in the use of cardiac medications in patients with coronary artery disease.

BACKGROUND: Benefits of aspirin and beta-blocker use in patients with coronary artery disease and angiotensin-converting enzyme (ACE) inhibitors in those with left ventricular systolic dysfunction are well documented in all age groups. OBJECTIVE: To investigate whether aspirin, beta-blockers, and ACE inhibitors are equally used in geriatric (> or =65 years) versus younger (<65 years) patients with coronary artery disease. SETTING: University-affiliated major academic hospital. METHODS: Records of 402 patients with coronary artery disease were analyzed for use of aspirin, beta-blockers, and ACE inhibitors. One hundred thirty patients with contraindications to use of these agents were excluded. RESULTS: Of 272 study patients, 85% were using aspirin and 71% beta-blockers. Among the patients with left ventricular systolic dysfunction, 79% were using ACE inhibitors. One hundred forty-seven patients were of geriatric age, whereas 125 were of younger age. No significant difference in the use of aspirin (82% versus 89%, P = 0.10), beta-blockers (71% versus 70%, P = 0.85), or ACE inhibitors (86% versus 69%, P = 0.13) was found between geriatric and younger patients. This lack of difference in use of cardiac medications between geriatric and younger patients persisted on gender-based subgroup analysis. On decade-of-age-based analysis, aspirin use was not equally distributed among all the decades of age (P < 0.005), but beta-blocker use was. CONCLUSION: Results of this study demonstrate equal use of aspirin, beta-blockers, and ACE inhibitors in geriatric versus younger patients with coronary artery disease. Aspirin use was not equally distributed among all the decades of age.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Zinc levels in seminal plasma of fertile and infertile men.

Zinc levels were measured in seminal plasma from 78 men classified on the basis of spermogram analyses into five groups: normo-, oligo-, astheno-, oligoastheno- and azoospermia. Higher zinc levels were found in seminal plasma from the group of asthenozoospermia men in comparison to normo-, oligoastheno- (p less than 0.001), oligo- and azoospermia men (p less than 0.01), while no significant differences appeared when other group pairs were compared. Seminal plasma zinc levels were positively correlated with sperm density (r = 0.6358, p less than 0.01) in asthenozoospermia men, whereas a significant negative correlation was seen in all groups between percentage forms showing normal progressive motility and zinc concentration in seminal plasma. Although zinc is required in seminal plasma for normal spermatozoon functionality, excessively high levels of this ion may be related with defective motility in asthenozoospermia samples.

Adult↗
PubMedDate not supplied

Hypoosmotic swelling test in normo-, oligo-, astheno- and oligoasthenozoospermic men before and after swim-up separation of spermatozoa.

Semen samples from a total 58 men were examined by routine semen analyses and the hypoosmotic swelling test. Samples were classified as normal, oligo-, astheno- or oligoasthenozoospermic on the basis of spermatogram findings. The latter three groups showed a significant decrease in the percentage of HOS positive forms in comparison to normal spermograms. All these samples were treated with the swim up technique to select motile spermatozoa, using a procedure similar to that routinely employed in clinical settings for homologous intrauterine insemination (IUI). Following swim-up, the ejaculate supernatant and residual precipitate were subjected to the hypoosmotic swelling test (HOS test), and the percentage of normal forms was determined in the three groups. The results showed greater percentages of HOS positive, normal and HOS positive-normal forms in the group of normal individuals than in any of the other three groups. The supernatant used in IUI showed a significant increase in percentage HOS positive spermatozoa, normal forms and spermatozoa which were both normal and HOS positive in comparison with the other two groups in normal and oligozoospermic samples, but not in samples which presented suboptimal motility (astheno- and oligozoospermia). In conclusion, the swim-up technique is effective in separating high-quality spermatozoa in normo- and oligozoospermic samples, although its effectiveness with astheno- and oligoasthenozoospermic samples should be questioned.

Humans↗