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Biomedical subjects

F Alvarez

Publications and source records attributed to F Alvarez.

At least 217 records · Page 12Linked to original sources
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↗
PubMed1989

Prospective study of the pituitary-ovarian function after tubal sterilization by the Pomeroy or Uchida techniques.

Surgical sterilization has become one of the most widely used methods of fertility regulation in the world. A common concern is the not yet clarified possible disturbance of the ovarian function resulting from the surgical procedure. A prospective study was carried out to contribute toward answering this question. Twenty subjects were enrolled in a longitudinal study of ovarian endocrine function before, and 2 and 6 months after, tubal ligation. The Pomeroy technique, which may compromise ovarian circulation, and the Uchida technique, which is free of this risk, were used randomly. Eight women who underwent to the Pomeroy technique and 9 who underwent the Uchida technique completed the protocol. Luteinizing hormone, follicle-stimulating hormone, estradiol, and progesterone were measured daily from days 10 through 18 of the cycle and every other day until the onset of the next menses. No change in any of the hormones studied was observed, with the exception of a significant increase in progesterone 2 months after tubal ligation by the Uchida technique.

Female↗
PubMed1989

Surgical Management and follow-up of vascular rings.

Thirty patients with aortic arch anomalies resulting in tracheo-oesophageal compression were treated during the period 1966 through 1987. These anomalies are important causes of upper respiratory and oesophageal obstruction in babies and small children. Although symptoms started within the first months of life in most cases, only 15 underwent surgery before six months and a delay of more than one year occurred in 5. Diagnosis was established by chest roentgenogram, barium oesophagogram and angiography. Thirteen (43%) patients had a double aortic arch, 9 (30%) cases had aberrant right subclavian artery and 6 (20%) patients had right aortic arch with ductus or ligamentum arteriosum. One (3.5%) patient had pulmonary artery sling and 1 (3.5%) case had right aortic arch and ductus arteriosum and aberrant right subclavian artery. Associated malformations were seen in 8 (27%) cases, (4 ventricular septal defects, 1 atrial septal defect, 1 coarctation of the aorta, 1 hypoplasia of left pulmonary artery, 1 left diaphragmatic eventration). Basic surgical procedure includes exposure through a left thoracotomy, complete identification of the anomaly and division of the constricting ring. 85% of the patients are asymptomatic and minimal to moderate stridor persists among the remainder. Severe tracheomalacia was responsible for the only two deaths in the series.

Aorta, Thoracic↗
PubMed1989

Clinical and immunological heterogeneity of anti-liver-kidney microsome antibody-positive autoimmune hepatitis in children.

A group of children with autoimmune hepatitis is characterized by the presence in their sera of anti-liver-kidney microsome antibody (LKMA) as defined by immunofluorescence. Immunoblot analysis of the sera of 21 such children using rat-liver microsome total proteins as antigen allowed separation into three groups--group 1, whose sera recognized a 50 kDa protein; group 2, whose sera recognized a 66 kDa protein; and group 3, whose sera recognized both proteins. Patients with the anti-66-kDa reactivity more often displayed an acute onset of the disease, less signs of portal hypertension, better sensitivity to immunosuppressive therapy, and less tendency to relapse. They also displayed a lower titer of anti-rat-liver microsome antibody in enzyme-linked immunosorbent assay (ELISA) and a serum reactivity with a rat-liver cytosolic protein. These results (a) indicate that the LKMA-positive autoimmune hepatitis of children is heterogeneous from both clinical and immunological view points, (b) suggest that children with anti-66-kDa reactivity could have a less severe disease than children with the 50-kDa reactivity, and (c) indicate that immunoblot analysis should be added to ELISA and immunofluorescence studies to achieve better characterization of these patients.

Adolescent↗
PubMed1989

Intracranial cavernous angioma in the dura.

Cavernous malformations located in the dura are rare. We present a case of a large cavernous malformation located in the anterior fossa and implanted in the dura of a pregnant woman. It showed great vascularization on an angiogram, and resembled a meningioma on computed tomographic scan. The operation was difficult because of the tumor's great vascularity and profuse bleeding.

Adult↗
PubMed1989

[Design, efficiency and application of experimental methods in heart transplantation].

Heart transplantation in children with end-stage heart disease or severe congenital heart defect with uncertain surgical palliation, like the hypoplastic left heart syndrome, has become an accepted form of therapy in certain selected Medical Centers. Increasing number of heart transplantation in children have resulted from increased survival attributable to the introduction of cyclosporine. Nevertheless, the diagnosis of rejection in infants and children remains controversial being a great challenge derived by the need for repetitive and routine heart biopsies. Taking in mind that a non-invasive electrophysiologic method could be considered a promising method for monitoring heart allograft rejection the present study was begun. A total of 306 heart transplantation was performed, 206 heterotopic on rats and 30 orthotopic on dogs. Non-invasive monitoring of heart rejection was made by electrophysiologic techniques using an epicardial lead implanted on the donor heart. R wave and slew-rate measurements were performed daily at 30', primero, segundo, tercero quinto and séptimo day postransplant. These measurements were later compared to histopathologic studies. R wave and slew-rate values of alogenic or rejecting hearts were found to decrease significantly as compared to singenic or non-rejecting heart along the days. This non-invasive electrophysiologic method may be considered a promising and suitable method for monitoring heart allograft rejection.

Animals↗
PubMed1989

[Hyperaluminemia and parathormone release].

Previous studies have shown that aluminum (Al) could inhibit parathyroid function. However, controversy still remains about the possible mechanisms implicated. Thus, the aim of this study was to evaluate the acute parathyroid hormone (PTH) response to intravenous Al infusion. Male Wistar rats were divided into two groups: Group A (n = 5): received 0.1 ml of saline. Group B (n = 5): received 0.5 mg of Cl3Al in 0.1 ml of saline. In both groups ionized calcium (Ca(+)+) decreased, but despite a similar degree of haemodilution, this change was only significant in group A. This variable Ca(+)+ decrease was followed by different responses in the PTH secretion. In group B there was a significantly (p less than 0.05) lower PTH release compared with control group. These results suggest that Al could directly inhibit the PTH secretion, and at the same time might exert an indirect effect on PTH release "blunting" the serum Ca(+)+ variations.

Aluminum↗