PubMed Health⌕ Search

Biomedical subjects

M Fernandez

Publications and source records attributed to M Fernandez.

At least 163 records · Page 9Linked to original sources
PubMed1989

Tyramine sulfoconjugation in relation to depression in migraine. A pilot study.

Tyramine sulfoconjugation following an oral tyramine load was determined in 30 patients suffering from migraine and 14 controls not regularly suffering from headache. Reduced tyramine sulfoconjugation was found in those patients with a history of major depressive disorder compared with controls. When the patients with a history of major depression were removed from the analysis, no differences were found between diet-sensitive and non-diet sensitive migraine patients and controls.

Depression↗
PubMed1989

Changes in collagen synthesis by human bone marrow fibroblasts with progressive subcultivation.

Bone marrow fibroblasts from normal and leukemic patients were used to investigate the relationship between serial subcultivation and changes in collagen synthesis. A regime was established to generate subcultures up to 35 cumulative population doublings (CPDs) in normal cells and to 9 CPDs in leukemic cells. In both types of cells, collagen synthesis decreased as subcultivation progressed. In normal cells, collagen synthesis was reduced to 10% of the original levels at 18 CPDs and in leukemic cells at 8 CPDs. In normal fibroblasts, collagen synthesis was more profoundly affected than overall protein synthesis by subcultivation. In acute lymphoblastic leukemia-derived fibroblasts, the decrease in collagen synthesis paralleled that of total protein.

Bone Marrow↗
PubMed1989

Intra-group differences in business participation: three Asian immigrant groups.

This study investigates ethnic and nativity differentials in self-employment based on the small-business experiences of 3 Asian immigrant groups in the US: Korean, Chinese, and Asian Indians. In light of the 1980 Census data, the intra- and the inter-group differences in the business participation rates of these Asian immigrant groups are examined. Findings reveal that each group has substantial intra-group differences in the business participation rate, and the differences can best be explained by the interactive approach proposed by this study. Moreover, a comparative study (inter-group comparison) of these intra-group differences opens a new avenue to understanding the various patterns of business participation among recent immigrants from Asia.

Americas↗
PubMed1989

Vitamin D metabolite-mediated hypercalcemia and hypercalciuria patients with AIDS- and non-AIDS-associated lymphoma.

Fifteen patients with lymphoma and hypercalcemia (greater than or equal to 11.0 mg/dL) were identified by screening the serum chemistry profile obtained from patients upon admission to the Los Angeles County/USC Medical Center. Seven of the 15 (47%) possessed a frankly elevated serum concentration of 1,25-dihydroxyvitamin D [1,25-(OH)2-D]. An additional patient with severe hypercalcemia (16.2 mg/dL) had a serum 1,25-(OH)2-D concentration in the midnormal range, not a suppressed value. To examine the potential existence of hypercalciuria in absence of overt hypercalcemia, prospective screening of 23 normocalcemic patients with lymphoma was undertaken. Four of the 23 patients (17%) had increased fractional urinary calcium excretion rates (0.35 +/- 0.3 mg calcium/100 mL glomerular filtrate [GF], mean +/- SE; normal, less than 0.16 mg/100 mL GF); two of the hypercalciuric patients had a frankly elevated serum 1,25-(OH)2-D concentration. Of the 19 hypercalcemic/hypercalciuric lymphoma patients identified, none had an elevated serum immunoreactive parathyroid hormone concentration. Fourteen of the 19 hypercalcemic/hypercalciuric patients (74%) suffered from B-cell neoplasms, three had Hodgkin's lymphoma, and two had adult T-cell leukemia/lymphoma. All hypercalcemic/hypercalciuric patients had widespread disease (stage III or IV). Six patients, four with hypercalcemia and two with hypercalciuria, had acquired immunodeficiency syndrome (AIDS). These data suggest that the deregulated synthesis of a 1,25-(OH)2-D-like metabolite is a common cause of hypercalcemia and hypercalciuria in patients with lymphoma including patients with AIDS-associated tumors.

Adult↗
PubMed1988

Stereological study of the early ultrastructural differentiation of chick embryo neuroepithelial cells during neurulation.

The neuroectodermal cells of chick embryos have been analyzed during neurulation by stereological and morphometrical ultrastructural methods in an attempt to describe their cytometric evolution. A profound change of cellular form coefficient was observed which is related to the typical process of columnarization of these cells. At stages 7 and 8, the nucleus appeared round in shape, probably due to a loss of pressure of the vitelline inclusions. In this sense, the volume density of these inclusions falls during this period. There was also a significant increase of the nuclear surface density, the significance of which is discussed on the basis of the nucleo-cytoplasmic interchanges and the differentiation process. At the same time, an increase in the number of mitochondria was observed, which is related to the neural folding process. Simultaneously, the amount of rough endoplasmic reticulum increases, presumably related to the remarkable changes of the embryonic extracellular matrix.

Animals↗
PubMed1988

Comparative scanning electron-microscopic study of the lingual papillae in two species of domestic mammals (Equus caballus and Bos taurus). II. Mechanical papillae.

The mechanical papillae of the horse and cow were studied by scanning electron microscopy in order to determine their morphostructural characteristics and the differences between the two species. The horse has only thin, small and interlaced filiform papillae, while the cow shows robust and more ordered filiform papillae. Furthermore, the cow tongue presents conical and lenticular papillae surrounded by a papillary groove. A characteristic distribution of stratified scales and channeled tracts is observed in conical and lenticular papillae but not in the filiform papillae. The morphostructural features of each papilla are analyzed and compared in each species and their possible significance is discussed.

Animals↗
PubMed1987

Therapy of hypercalcemia of malignancy.

An appreciation of the pathogenesis of the hypercalcemia of malignancy is essential to its management. At the outset, since most patients with symptomatic hypercalcemia of malignancy are dehydrated, infusion of 2 to 3 liters of saline per day will at least partially reduce serum calcium levels. Induction of calciuresis by infusing larger volumes of saline simultaneously with parenteral administration of furosemide may reduce the serum calcium concentration to normal in the short term. Of major importance in long-term therapy, however, are drugs that inhibit bone resorption, a major cause of hypercalcemia. These include calcitonin, plicamycin, glucocorticoids, prostaglandin synthetase inhibitors, and the diphosphonates. These agents may provide long-term control of hypercalcemia in many patients. Reduction of intestinal calcium absorption by dietary means or by glucocorticoid therapy is often effective in the rare subset of patients with increased serum levels of 1,25-dihydroxyvitamin D. Oral and intravenous phosphorus therapy may be effective via unknown mechanisms in some patients. The diphosphonates, in particular, should greatly facilitate management of both acute and chronic hypercalcemia of malignancy. Daily intravenous infusion of etidronate disodium (etidronate) with saline over a period of three to six days, for example, appears to be a safe and effective means of restoring serum calcium concentrations to the normal range. Study results have shown that more than 90 percent of patients have a response to etidronate. Oral administration of the drug has been demonstrated to maintain normal serum calcium concentrations.

Bone Resorption↗
PubMed1987

Detoxification enzymes following intrastriatal kainic acid.

A complete explanation of the neurotoxicity that follows kainic acid (KA) injection into the rat striatum is lacking. An assessment of the chronological course after intrastriatal KA injection of the activities of enzymes preferentially concentrated in glia or involved in the detoxification of oxygen metabolites is accomplished. An enhancement of the specific activities of glutathione peroxidase (GP) and catalase is found without an alteration in the specific activity of superoxide dismutase (SOD). There is no increase in the in vivo striatal levels of malondialdehyde, a putative indicator of lipid peroxidation, the expected result of cell membrane damage from oxygen metabolites. Understanding the mechanism and importance of the preferential induction of the activities of the detoxification enzymes will require further study.

Animals↗
PubMed1987

Detection of mutagenicity in drinking water using a micronucleus test in newt larvae (Pleurodeles waltl).

We have previously described a micronucleus test using erythrocytes from larvae of the urodele amphibians Pleurodeles waltl (pleurodele) and Ambystoma mexicanum (axolotl). The test is based on a comparison of the levels of micronucleated erythrocytes in blood smears from larvae reared in water containing a clastogen, with the levels from larvae reared in purified water. Using larvae from the pleurodele, we have employed this test to evaluate mutagenic activity in drinking water. Groups of larvae were reared in tap water, while control groups were reared in tap water which had been filtered over sand and active carbon to remove micropollutants. Seven separate tests carried out between October 1985 and May 1986 all gave positive results of varying degree depending on the time of year. This test is therefore able to detect clastogens in normal drinking water. It could be used for quality control of drinking water during the various stages in the treatment of raw water without any requirement for prior extraction or concentration of micropollutants.

Animals↗
PubMed1987

An antioxidant protects against the clastogenic effects of benzo[a]-pyrene in the newt in vivo.

The clastogenic effect of benzo[a]pyrene (B[a]P) was observed in newt larvae by the formation of micronuclei in circulating red blood cells (RBCs). The level of micronucleated RBCs depended on the concentration of B[a]P (0.025, 0.05 and 0.1 p.p.m.) in the water in which the animals were reared. The synthetic antioxidant, 2(3)-tert-butyl(4) hydroxyanisole (BHA), currently used as a food additive (E 320), was added to the water at concentrations of 0.5, 1.0 and 1.5 p.p.m. It reduced the clastogenic effect of B[a]P in the test larvae, with the most marked effect at a concentration of 0.5 p.p.m. The genotoxicity of B[a]P and the protective action of BHA in the newt are discussed.

Animals↗
PubMed1987

Postoperative acute acalculous cholecystitis.

A 5-year experience with postoperative acute acalculous cholecystitis is reported. The series concerns 9 male patients ranging in age from 28 to 69 years, with a mean age of 46 years. All underwent major surgical procedures and complications appeared in the postoperative course. Clinically, 89% of patients developed sepsis and 66% jaundice. Klebsiella pneumoniae was the microorganism most frequently isolated from the blood, intraabdominal and wound fluid collections. It is emphasized that the diagnosis of this form should be clinical and it should be immediately suspected whenever intraabdominal signs develop. A review of the international literature on the subject is presented. The etiology and pathogenetic mechanisms of postoperative acute acalculous cholecystitis are discussed.

Acute Disease↗
PubMed1986

Stereological analysis of ultrastructural changes of surrounding tissues to neuroectoderm during chick embryo neurulation.

The cytometric evolution of different subcellular components in the epiblast and the mesoderm of chick embryo during neurulation has been studied with stereological methods. The coefficient of cellular form (CFc) has specific values for each type, the epiblast having a mean CFc of 0.474, while the mesoderm, which has ellipsoidal cells, has a mean CFc of 0.643. The nucleus does not show any change of its coefficient of form although its surface density increases significantly. The proportion of mitochondria, present in the cells of each embryonic layer, remains constant during the 4 stages, being higher in the mesoderm cells (epiblast 3.6%; mesoderm 4.3%). The epiblast cells show a stable vitelline reserve, though the relative proportions of lipid bodies and yolk droplets vary: the volume density of yolk droplets increases from stage 5 (3.1%) to stage 8 (7.7%), while the lipid bodies diminish from 7 to 3.6% during this period. The mesoderm cells undergo a remarkable loss of vitelline volume during the same period. The rough endoplasmic reticulum of each cellular type has a remarkable length density increase, the significance of which is discussed in relation to production of extracellular matrix.

Animals↗
PubMed1986

Prefrontal cortex excitability in early postnatally malnourished rats.

The effect of early postnatal malnutrition on the responsiveness of the rat prefrontal cortex was studied by determining excitability thresholds and fatigability to direct cortical stimulation. Malnutrition imposed during the period of rapid brain growth caused a significant increase of cortical chronaxie values as well as increased fatigability of direct cortical responses, indicating a detrimental effect on the axodendritic synapses. Since the prefrontal cortex plays an important role in the temporal organization of behavior, a dysfunction of this cortical area could be a causal link between nutritional and behavioral deficits.

Animal Population Groups↗
PubMed1986

Experimental findings on the estrogenic activity of estradiol enantate.

In a first attempt to find out the estrogenic activity of the monthly injectable contraceptive composed of dihydroxyprogesterone acetophenide 150 mg + estradiol enantate 10 mg (Perlutal, Topasel), estradiol enantate (estra-1,3,5(10)-triene-3-ol-17 beta-heptanoat), estradiol benzoate and ethinylestradiol were compared in rats of the Chbb: THOM species. Estradiol benzoate potency was significantly higher than that of estradiol enantate: 20.34 (15.57-26.31) times in the vaginal cornification test in castrated females; 2.21 (1.63-2.98) times in the uterine weight test also in castrated rats and 2.91 (1.86-4.54) times in the vaginal opening test in immature rats. Ethinylestradiol, orally administered in the first two tests, was less active than the other two parenterally given substances; it overcame them in the vaginal opening test, when all substances were perivaginally administered. The duration of action of equivalent doses on the vaginal smear in castrated females resulted higher for estradiol enantate: 2.52 times more than estradiol benzoate and 5.2 times more than ethinylestradiol. Based on these results and on preexistent literature, the estradiol enantate dosis which would be sufficient to obtain the endometrial proliferation in women was extrapolated and compared with those already established of estradiol benzoate and ethinylestradiol. Finally, the possibility that the estrogenic potency of the injectable contraceptive treatment can be similar or lower than the oral one with pills containing ethinylestradiol 0.030-0.050 mg is discussed.

Animals↗
PubMed1986

Pharmacokinetic studies of estradiol enantate in menopausic women.

Healthy menopausic women received 10 mg i.m. of estradiol enantate (estra-1,3,5(10)-triene-3-ol-17 beta-heptanoate, one of the components of Perlutal or Topasel). Their estradiol serum levels were determined by radioimmunoassay (RIA) on days 1, 2, 3, 6, 8, 10, 13, 15, 17, 20, 22, 24, 27, 29 and 31 after the injection. Based on these data, the elimination rate constant (K = 0.12445 d-1), the elimination half-life (t1/2 = 5.57 d), the absorption rate constant (Kabs. = 1.5050 d-1), the absorption half-life (t1/2 abs. = 0.46 d) and the volume of distribution (Vd = 5087 l) were calculated. These results are compared with others not obtained by RIA and discussed from a therapeutic-clinical point of view.

Estradiol↗
PubMed1985

Influence of undernutrition during gestation and suckling on development and sexual maturity in the rat.

The effects of undernourishment during gestation and suckling on rats subsequently fed ad libitum for 4 mo after weaning are explored. We measured the following: weight at birth and over a 5-mo period; sexual behavior of adult males; curiosity; basal physical activity; morphometric measures; organ weights (absolute and relative) including brain, testicles and seminal vesicles in males 5 mo of age; and the O2 uptake of some brain and glandular structures in males at 5 mo of age. Body weight of the malnourished animals was consistently lower than that of the controls. Compared to controls sexual behavior in undernourished males was significantly reduced, while curiosity test and basal physical activity were increased. The absolute weights of all organs (except the pituitary gland) were significantly lower in malnourished males at 5 mo than in controls. Compared to controls, relative weight of brain was greater and that of seminal vesicles was less in the male rats. Oxygen uptake was significantly lower in the pituitary gland and testicles of malnourished males than of controls. In view of these results, it can be concluded that malnutrition in utero and while suckling affects fundamental parameters of both development and reproductive function in the male offspring 4 mo after feeding ad libitum is begun at weaning.

Animals↗