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Biomedical subjects

F Alvarez

Publications and source records attributed to F Alvarez.

At least 37 records · Page 2Linked to original sources
PubMed1991

Helminth parasites in some Spanish bats.

Nineteen bats of the species Rhinolophus ferrumequinum, R. hipposideros, Myotis myotis, M. nattereri, Pipistrellus pipistrellus, Barbastella barbastellus, Eptesicus serotinus and Plecotus auritus captured in N. W. Spain in 1983-85 were found to contain the following helminth parasites: Mesotretes peregrinus (found in 4 host species and making up 31% of all helminths); Plagiorchis vespertilionis (10.5%, in 2 host species); Strongylacantha glycirrhiza, Molinostrongylus alatus, Molineidae gen. sp., Capillariidae gen. sp., Hymenolepis acuta, Cestoda gen. sp. and Trematoda gen. sp. I and II (5.2% in 1 host species).

Animals↗
PubMed1991

Common airborne allergens and their clinical relevance in the Caracas valley.

In order to determine the sequential prevalence of pollen grains and fungi spores in the city of Caracas by the volumetric method of collection and its effect on the population at risk, the first multidisciplinary team of aerobiological research was structured through a protocol designed for five experimental stages namely: a) Determination of the climatological parameters: temperature, relative humidity, speed and wind direction, precipitation and atmospheric stability, through simultaneous records of meteorological status located in the metropolitan area of Caracas; b) Collection, identification, classification and determination of the local distribution of the most important pollen grains existing in the zone under study; c) Collection, identification and classification of the most important fungi spores in the area; d) Preparation of the first pollinic calendar of Caracas and e) Evaluation of possible implication of the environment and the response through the IgE antibody in the selected patients in the area under study. Our results show: 1) The climatic conditions existing during the sampling period coincide with the analysis of the last 20 years in the Valley of Caracas. 2) The Venezuelan Central University (UCV) station was elected as the most representative point for permanent sampling. 3) An ideal statistical method is obtained in order to determine the spatial arrangement in the sampler rod of a dense type of fungi spores typical of the area under study. 4) The first pollinic calendar of Caracas was structured and 5) A seasonal tendency of the IgE response is shown. These results suggest an evident interrelation between the suggested concept of polyseasonality and antigenic polysensitization, and between individual seasonality with a specific reactivity and, finally, between tropical mixed seasonality with the expression of combined respiratory pathologies in our environment.

Air↗
PubMed1991

Lung and hearth nematodes in some Spanish mammals.

Thirteen host species belonging to the orders Rodentia, Insectivora and Carnivora from various localities in Galicia (NW Spain) were examined for heart and lung parasites. The following species were found: Parastrongylus dujardini (5.5%) in Apodemus sylvaticus, Crenosoma striatum in Erinaceus europaeus (83%), Angiostrongylus vasorum, Crenosoma vulpis and Eucoleus aerophilus in Vulpes vulpes (3, 3.46 and 0.50%, respectively), Crenosoma taiga in Putorius putorius (100%) and Crenosoma sp. in Meles meles (25%). In Crocidura russula nematode larvae were found (3.3%). Mus musculus, Rattus norvegicus, Rattus rattus, Talpa caeca, Sorex araneus, Genetta genetta and Canis lupus were not parasitized by lung or heart parasites.

Animals↗
PubMed1990

BiP expression is not increased by the accumulation of PiZ alpha 1-antitrypsin in the endoplasmic reticulum.

PiZ, a mutant human alpha 1-antitrypsin, is associated with liver and pulmonary disease and is characterized by defective secretion and accumulation of the protein in the endoplasmic reticulum. We tested the hypothesis that BiP (a protein that binds newly synthesized protein in the endoplasmic reticulum, prevents secretion of incorrectly folded protein, and solubilizes protein aggregates), could play a part in the retention of PiZ alpha 1-antitrypsin in the endoplasmic reticulum. Subcellular fractions from PiM (normal) and PiZ livers were prepared and analyzed by immunoblotting. No increase of BiP was detected in the PiZ liver. In addition, when total RNA from the same livers were analyzed by slot and Northern blot hybridization, no difference was found in the level of BiP mRNA between PiM and PiZ livers. Similar results were found in clones of CHO and MDCK cells transfected with PiM of PiZ alpha 1-antitrypsin cDNAs. These results indicate that BiP does not play a part in the retention of PiZ alpha 1-antitrypsin and suggest that PiZ protein is not misfolded.

Animals↗
PubMed1990

Long-term contraception with the levonorgestrel 20 mcg/day (LNg 20) and the copper T 380Ag intrauterine devices: a five-year randomized study.

An intrauterine device, releasing approximately 20 micrograms/day of levonorgestrel (LNg 20), used by 1124 women, was studied in a randomized trial of five years duration in comparison with the Copper T, model TCu 380Agm in 1121 women. At five years, the gross cumulative pregnancy rate of 1.1 +/- 0.5 per 100 among users of the LNg 20 devices was not significantly different from the rate of 1.4 +/- 0.4 per 100 experienced by users of the Copper T 380Ag. The steroid-releasing IUD had significantly higher termination rates for expulsion and amenorrhea, a significantly lower termination rate for other menstrual problems and pain, and a lower continuation rate. The five-year continuation rate among women using the TCu 380Ag was 40.6 per 100 as compared with that of 33.0 per 100 among women randomized to the LNg 20 device (P less than .001). Terminations attributed to amenorrhea with the LNg device primarily account for differences in continuation. These two intrauterine devices are the most effective long-term, reversible IUDs yet reported in the literature. No other contraceptive methods have exhibited such low long-term pregnancy rates in randomized comparative trials.

Adolescent↗
PubMed1990

A randomized trial of the Gyne T 380 and Gyne T 380 Slimline Intrauterine Copper devices.

To facilitate manufacture and insertion of the Gyne T 380 IUD, design changes were instituted. Copper collars were seated flush at the ends of the horizontal crossbar of the device. A randomized study of the Gyne T 380 Slimline, the new design, was undertaken in comparison with the standard Gyne T 380. A total of 996 women were enrolled, with 698 Slimline insertions and 298 of the standard Gyne T. No statistically significant difference in ease of insertion or in performance was detected between the models. At one year, the pregnancy rate of each model was below 0.5 per 100 and the continuation rate was 79-80 per 100. Pelvic inflammatory disease or endometritis was found in one percent of subjects in the first year. This is the seventh multicenter randomized study of a collared T IUD with 380 mm2 of copper surface. In all seven, the one-year gross pregnancy rate has been 1.2 per 100 or lower.

Adult↗
PubMed1990

Long-term culture of rat liver cell spheroids in hormonally defined media.

Liver cells of new-born rats, which were found to be able to form spheroidal aggregates when cultured on a nonadherent plastic substratum, were studied under various conditions of culture, mainly by adding different nutrients and growth factors to the culture medium. Analysis of hepatocyte-specific functions was carried out by immunoprecipitation to detect specific proteins newly secreted by liver cell spheroids on different days of culture. When no supplement was added to culture medium, the secretion of albumin and transferrin by liver cell spheroids was no longer detectable after 2 weeks of culture. When dexamethasone, glucagon, insulin, and EGF were added to culture medium, the secretion of albumin and transferrin remained detectable at least until 60 days of culture. This was even more striking when trace elements were added in addition to the three hormones and EGF. The effects of addition of these various factors to culture medium were also detectable with respect to alpha-FP secretion. Even after 54 days of culture in total supplemented medium, these liver cell spheroids could be transferred on a collagen-coated plastic substratum to form a monolayer of uniform liver parenchyma-like cells. The presence of extracellular matrix-like material was observed on the surface of cell spheroids. This could be responsible for attachment and fusion between cell spheroids. Thus, liver cell spheroids cultured in total supplemented medium ensured cell attachment to a biological matrix and cell-cell contact, which is thought to help maintain cell differentiation. Liver cell spheroids offer the possibility of toxicological and pharmacological studies as well as cultures in biomatrix and coculture systems. In addition these liver cells can be used for experiments in liver cell transplantation.

Animals↗
PubMed1990

Anti-liver-kidney microsome antibody-positive autoimmune hepatitis presenting as fulminant liver failure.

A 17-month-old girl presented with acute hepatitis, which took a fulminant course leading to death 2 months after onset. No known cause of fulminant liver failure could be identified. Postmortem examination of the liver showed massive multilobular necrosis and areas of severe piecemeal necrosis. A high level of total serum gamma-globulins raised the possibility of autoimmune hepatitis. Search for anti-liver-kidney microsome antibody in the patient's serum was positive by immunofluorescence and enzyme-linked immunosorbent assay. Western blot analysis showed reactivity of the antibody with a 50-kDa protein identical to that observed in children with autoimmune hepatitis. This patient's history strongly suggests that autoimmune hepatitis can present as fulminant liver failure in children. Early diagnosis in such a patient could lead to early immunosuppressive therapy.

Antibodies↗
PubMed1990

Thalamic cavernous malformation. Case report.

A 50-year-old man with a right hemiparesis was found to have a cavernous malformation in the left thalamus. The diagnosis was made using magnetic resonance (MR) imaging. The vascular malformation was totally removed by means of a transcallosal interhemispheric surgical approach, but the patient's neurological deficit worsened. The role of MR imaging in establishing the diagnosis is emphasized and other published cases with thalamic locations are reviewed.

Aphasia, Broca↗
PubMed1990

Enzyme- and immuno-histochemical study of the thymic stroma in the rainbow trout, Salmo gairdneri, Richardson.

Owing to the lack of data about thymic non-lymphoid cells in fish we decided to perform a histochemical characterization of these cells in order to ascertain their relationships to other thymic components. In the present study we analyze the enzyme-histochemical patterns for acid phosphatase, alkaline phosphatase, non-specific sigma-naphthyl acetate esterase and 5' nucleotidase activities, as well as the presence of keratin demonstrated by immunoperoxidase staining, in the non-lymphoid cell populations of the thymus of the rainbow trout, Salmo gairdneri. According to their location in the organ, morphology and histochemical reactivities, we were able to define seven different subpopulations of keratin-positive epithelial cells: 1) Epithelial cells limiting with the capsular and septal connective tissues; 2) Subcapsular epithelial cells; 3) Stellate epithelial cells of the inner thymic zone; 4) Large, ovoid epithelial cells of the inner thymic zone; 5) Acidophilic epithelial cells of the outer thymic zone; 6) Cystic cells; and 7) Goblet cells. The significance of the heterogeneity of the epithelial cell (EC) population, its specific distribution in the organ, which apparently conforms distinct cell microenvironments, as well as the possible phylogenetical relationships between these microenvironments and the classical cortex and medulla of the mammalian thymus, are discussed.

5'-Nucleotidase↗
PubMed1990

[Physiological mode of pacing in pediatrics].

The concept of physiologic pacing is often primarily to involve the preservation of atrioventricular synchrony. Nevertheless, specially in children there are other mechanisms different than atrial filling to improve cardiac output such as heart rate increase with exercise. Taking as physiologic pacing those modes of pacing improving hemodynamic condition of the patient we must add to the DDD, the DDDR and SSIR modes of pacing. In this report our experience with 70 consecutive children paced in physiological mode of pacing is described: 51 in SSIR mode, DDD in 16, and DDDR in 3 cases. In five out of the 16 cases with DDD mode it was found an unidirectional crosstalk and in two atrial sensing failure (failure rate with DDD of 47.75% at 48 months of follow-up). In 26 children with rate responsive pacing by means of activity sensing a treadmill exercise test according to Bruce protocol was performed found a significant increase in both, heart rate and maximal work capacity, associated to an improvement in the clinical status and no evidence of arrhythmias in any case. In conclusion, rate responsive pacing by means of activity sensing in children is an adequate, reliable and effective physiological mode of pacing.

Adolescent↗
PubMed1989

Anti-liver-kidney microsome antibody type 1 recognizes human cytochrome P450 db1.

Anti-liver-kidney microsome antibody type 1 (LKM1), present in the sera of a group of children with autoimmune hepatitis, was recently shown to recognize a 50 kDa protein identified as rat liver cytochromes P450 db1 and db2. High homology between these two members of the rat P450 IID subfamily and human P450 db1 suggested that anti-LKM1 antibody is directed against this human protein. To test this hypothesis, a human liver cDNA expression library in phage lambda GT-11 was screened using rat P450 db1 cDNA as a probe. Two human cDNA clones were found to be identical to human P450 db1 by restriction mapping. Immunoblot analysis using as antigen, the purified fusion protein from one of the human cDNA clones showed that only anti-LKM1 with anti-50 kDa reactivity recognized the fusion protein. This fusion protein was further used to develop an ELISA test that was shown to be specific for sera of children with this disease. These results: 1) identify the human liver antigen recognized by anti-LKM1 auto-antibodies as cytochrome P450 db1, 2) allow to speculate that mutation on the human P450 db1 gene could alter its expression in the hepatocyte and make it auto-antigenic, 3) provide a simple and specific diagnostic test for this disease.

Autoantibodies↗
PubMed1989

Contact phase of blood coagulation in cardiogenic pulmonary oedema (CPO) and adult respiratory distress syndrome (ARDS).

In order to assess the role of the kallikreinkinin (k-k) system in the pathogenesis of pulmonary oedema, we studied the contact phase factors of blood coagulation, as well as the haemodynamics and blood gas changes in 34 patients with pulmonary oedema, 23 of them with Adult Respiratory Distress Syndrome (ARDS) and 11 with cardiogenic pulmonary oedema (CPO). We have verified significant differences in the haemodynamic pattern and blood gases between the two groups of patients, which corroborate the previously established differences between both types of pulmonary oedema. Our results reveal k-k system activation in ARDS patients, with a significant fall in factor XII (p less than 0.05), prekallikrein (p less than 0.01), alpha-2-macroglobulin (p less than 0.01) and high molecular - weight kininogens (p less than 0.005), with a rise in C1-esterase inhibitor (p less than 0.001) in comparison with patients with CPO. All of the CPO patients had normal prekallikrein levels, whereas 15 out 23 ARDS cases (65%) had decreased prekallikrein values. Our results suggest that the k-k system activation could play a role in the pathogenesis of ARDS. Estimation of prekallikrein levels may be helpful in the differential diagnosis of ARDS.

Adult↗