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Biomedical subjects

A Castro

Publications and source records attributed to A Castro.

At least 163 records · Page 9Linked to original sources
PubMed1997

[Systemic capillary leak syndrome].

The systemic capillary leak syndrome is a rare condition, with a high mortality rate, characterised by recurrent episodes of generalized edema, with hemoconcentration and hypoproteinemia, associated with paraproteinemia. Pathophysiologically, this syndrome is caused by a sudden, reversible increase in capillary permeability, with a rapid shift of plasma from the intravascular to the extravascular compartment with subsequent hypovolemic shock. We report a new patient of this unusual condition, and we review its diagnostic and therapeutic aspects.

Capillary Leak Syndrome↗
PubMed1997

[Electrophysiologic characteristics of the atrium during chronic atrial fibrillation in man].

AIM OF THE STUDY: To evaluate the electrophysiologic characteristics of human atria during chronic atrial fibrillation. METHODS: The study was performed in 24 patients who underwent low energy intracardiac atrial cardioversion for chronic atrial fibrillation before the procedure itself. No patients have been assuming antiarrhythmic drugs for a period of at least 5 half-lives of the drug. In 10 patients the possibility of local capture in several atrial sites (7 tested) by means of high-rate atrial pacing was evaluated. A Franz catheter for recording of monophasic action potential (MAP) and for atrial stimulation was positioned in the right atrium at a distance of 1 cm from a quadripolar catheter which was also positioned for the recording of the bipolar electrogram by the distal and proximal pairs and of the unipolar electrogram by the distal electrode. A decapolar catheter for shock delivery was positioned in the coronary sinus as well. In the remaining 14 patients an additional quadripolar catheter for His recording was positioned but atrial stimulation was not performed. Furthermore, recordings of the bipolar and unipolar electrograms were obtained in several sites and the correlation between MAP and bipolar electrogram morphology was evaluated. The existence of a difference in fibrillation cycle-length in different sites suggestive of a dispersion of refractory periods was also screened. Wells' and Waldo's classification was used for bipolar electrograms whereas MAP was classified into type 1 (regular), type 2 (partially irregular), and type 3 (totally irregular). RESULTS: In 10 patients submitted to atrial stimulation, local capture was obtained in 37 out of 43 stimulation sites (86%). Local capture was more frequently obtained in the lateral wall than in other sites (p < 0.05). The capture was obtained only in type 1 and type 2 atrial fibrillation. In the remaining 14 patients a perfect correlation (100%) between type 1 and 3 atrial fibrillation and type 1 and 3 MAP respectively was observed. In type 2 atrial fibrillation the correspondence was lower (67%). Fibrillation cycle-length contemporary recorded in the 6 different atrial sites were significantly different in 8 patients out of 12 (67%) in whom a stable recording could be obtained in basal conditions. CONCLUSIONS: 1) In chronic atrial fibrillation an excitable gap allowing local capture is present in the majority of patients and in most atrial sites, at least in the right atrium. 2) The morphology of bipolar and MAP recordings are fairly correlated and they reflect the complexity and the degree of synchronization of the arrhythmia. 3) A dispersion of refractoriness seems to contribute to the maintainance of the arrhythmia.

Action Potentials↗
PubMed1997

[Latent long QT syndrome: discription of a clinical case].

Latent forms of long QT syndrome have been already reported. We describe one case of a 27 years old female patient who experienced an episode of cardiac arrest after several puffs of salbutamole. The malignant arrhythmia causing the cardiac arrest was torsade de pointes degenerated into ventricular fibrillation. The patient ECG showed a normal QTc basal interval and the correct diagnosis was made by contemporary recording of the ECG and MAP during orciprenalina infusion. After drug infusion, we have recorded a MAP lengthening and a dispersion of MAP duration between the right ventricular apex and the right ventricular outflow tract. These modifications were concomitant with the appearance of "humps" (probably related to the presence of early afterdepolarizations), a QT interval lengthening and morphologic changes of the T and U waves.

Administration, Inhalation↗
PubMed1997

[Familial strio-pallido++-dentate calcification].

INTRODUCTION: Calcification of the dentate nucleus of the cerebellum may be seen on cerebral CT in 0.3-0.5% of patients with no symptoms or extra-pyramidal signs. Although there are many causes, some cases show a family incidence. Clinical cases. We present two cases, mother and son, in whom the predominant clinical findings were poor language and a bilateral extrapyramidal syndrome. Laboratory tests, hormone and immunological studies were normal. In both patients cerebral CT showed bilateral calcification of the basal nuclei and dentate nuclei of the cerebellum. DISCUSSION: Our patients fulfilled the clinical and neuro-imaging criteria described in familial strio-pallido-dentate calcification. There is no relationship between the duration and intensity of symptoms, and the extension of the calcification. However, all patients with calcification show clinical features. The predominant features are poor language and a bilateral extra-pyramidal syndrome. These observations indicate that in patients with calcification of the basal ganglia and dentate nuclei of the cerebellum it is necessary to study first degree relatives in order to identify the condition.

Aged↗
PubMed1997

[Acute effects of ventricular and bicameral stimulation on plasma levels of natriuretic hormone].

Atrial natriuretic factor (ANF) is a peptide produced by the atrium in response to increases in atrial pressure. It is a potent vasodilator and recent studies suggest that ANF may modulate vasomotor changes in patients (pts) with pacemaker (PM) syndrome. To evaluate the incidence of pacing mode on peptide secretion, plasma concentrations of ANF were determined in 32 pts (18 men and 14 women, mean age 71 +/- 4 years) with a DDD PM implant. Blood samples were collected one hour after a randomly assigned PM programming either in VVI or DDD mode at 70 ppm. Mean plasma ANF levels were 84.12 +/- 51 pg/ml in DDD mode and 156.0 +/- 15 pg/ml in VVI mode (p < 0.05). In 12 pts presenting ventriculoatrial retroconduction, the ANF levels were 77.16 +/- 50 pg/ml during DDD stimulation and 219.0 +/- 16 pg/ml during VVI stimulation (p < 0.05). ANF level was 88.50 +/- 46 pg/ml in DDD mode and 114.25 +/- 65 pg/ml in VVI mode in the 20 pts without AV retroconduction (p < 0.05). During DDD mode, 18 patients showed a DVI stimulation whereas 14 showed a VDD stimulation: the mean ANF level was 67.40 +/- 15 pg/ml during DVI and 100.40 +/- 28 pg/ml during VDD stimulation; the difference between these data was not significant. The increase in ANF levels during VVI pacing confirms the lower haemodynamic performance of this stimulation mode. The increase of ANF levels during VVI stimulation, which was in the subgroup without AV retroconduction, confirms the benefits of DDD stimulation also in this group of patients as well. Atrial pacing at physiological rates does not trigger the release of ANF.

Aged↗
PubMed1997

[The efficacy of interferon alfa treatment in chronic hepatitis C in relation to the serum concentration of RNA-HCV and the viral genotype].

BACKGROUND: To determinate the viral variables (viremia and genotype) and patients variables (route and years of infection, histology, etc) related with response to the treatment with alpha intefferon in patients with chronic hepatitis C. SUBJECTS AND METHODS: We have studied 50 patients with chronic hepatitis C that received an intefferon treatment during a year. In all them it was accomplished a hepatic biopsy before of the beginning of treatment and it was studied the viral load by quantitative PCR (Monitor, Roche) at the beginning of treatment, at four weeks and at the end of treatment. It was determined the HCV genotype by method INNO-LIPA (Boehringer Inghelheim). RESULTS: 8 patients (16%) achieved a complete sustained response during all the follow-up period (13.8 + 1.6 months); 8 patients responded but relapsed when the intefferon was interrupted and 34 patients not responded. The responders had lower viremia (p < 0.032) and HCV RNA negative at the fourth treatment week (p < 0.0082). The genotype 1b was the most frequent, the one which was presenting a smaller percentage of response and it was associated with a higher viremia. Cirrhotic patients were the worse responders. Ex-lDAs were better responders than the others groups, however this difference did not show statistics meaning. CONCLUSIONS: A low pretreatment HCV-RNA level seems to be indicative of a sustained response to IFN, Whereas a high level seems to be indicative of a non sustained response to IFN. Negativization of HCV-RNA at week four is a good indicator of response to intefferon. Genotype 1b is the most frequent and the worse responder. To have 1b genotype, high pretreatment HCV-RNA level and to be viremic at four treatment seems to be indicative of non response.

Adult↗
PubMed1997

Spleen-derived stromal cells. Adhesion molecules expression and lymphocyte adhesion to reticular cells.

The final steps of lymphocyte differentiation occur in secondary lymphoid organs where B and T lymphocytes interact with the lymphoid microenvironment. Although numerous studies describe the interactions of murine lymphocytes with dendritic, follicular and other antigen presenting cells, little is known on the interactions between lymphocytes and reticular cells, an important cellular component of spleen stroma. In this work we describe the culturing of complete murine spleen stromas and of two cell lines, Sp-1 and Sp-2, identified as of possible reticular origin, and describe the adhesive interactions between murine lymphocytes and human lymphoid cells with murine spleen stromal cells. FACS analysis indicates that the Sp-1 cell line shows a single cell type expressing VCAM-1 and CD44 constitutively. They do not express any of the markers described for follicular cells, interdigitating cells, macrophages or endothelial cells. Our data suggests that these cells represent a population of spleen reticular cells. The Sp-2 cell line shows two phenotypically different cell types that grow in association. FACS analysis demonstrates that both cell types express VCAM-1 and CD44 constitutively, but that they can be differentiated by the expression of CD11b and FcR. These data suggest that the Sp-2 cell line is composed of one type of stromal cell growing over an adherent layer of reticular cells. Furthermore, analysis of the non-B non-T cell fraction prepared from murine spleen shows that approximately 30% of these cells correspond to the CD44/VCAM-1 double positive cells. Murine B and T cells adhere to the complete stromas and to Sp-1 and Sp-2 cell lines. Activation of B cells with LPS had no effect on binding while binding of T cells to complete stromas increased up to threefold after Con-A treatment. Adhesion of human lymphoblastoid Daudi cells to complete spleen stromas is blocked by an anti-(murine) VCAM-1 antibody but not by an antibody to the (human) integrin alpha 4 subunit, while adhesion to the Sp-1 and Sp-2 stromas is blocked by antibodies against both molecules. Also, adhesion of Ramos cells to Sp-2 stromas is inhibited by antibodies to the integrin alpha 4 subunit and to murine VCAM-1. Antibodies to other adhesion receptors such as the integrin beta 2 subunit, ICAM-1 or CD44 have no effect on human cell binding to these stromas. Our results suggest that we have isolated a fraction of splenic reticular cells and that these cells can be cultured as a distinct cell line. The finding that these cells express CD44 and VCAM-1 constitutively and use some of these molecules for lymphocyte binding suggests that spleen reticular cells may be involved in the regulation of normal lymphocyte traffic through the spleen.

Animals↗
PubMed1996

Inhibition of transcription factor Stat1 activity in mononuclear cell cultures and T cells by the cyclic AMP signaling pathway.

Activation of T cells results in a cascade of gene activation and subsequent proliferation and differentiation into effector phenotypes. The regulation of transcription factors belonging to the signal transducer and activator of transcription (STAT) family was analyzed in PHA-activated mononuclear cells and in purified T cells activated by cross-linking cell surface CD3. Cell activation resulted in a delayed induction of STAT DNA-binding activity, which was sustained for several days, was composed predominantly of Stat1 and Stat3, and was blocked by cycloheximide and actinomycin D. Increased Stat1 and Stat3 mRNA and protein levels were detected, respectively 4 and 24 h after activation. Stimulation of the cAMP signal transduction pathway, which skews cytokine production toward a Th2 pattern, resulted in the preferential suppression of Stat1 activity. cAMP inhibited the induction of expression of IL-2 receptor components, but did not inhibit IL-4 receptor alpha-chain and CD69 expression or the induction of activator protein 1 transcription factors. cAMP signaling inhibited Stat1 at several different levels, including suppression of DNA binding and down-regulation of Stat1 protein and mRNA levels. Our results demonstrate the regulation of STAT activity by a signaling pathway that regulates the T cell functional phenotype and is distinct from the cytokine-activated Janus kinase-STAT signaling pathway.

Base Sequence↗
PubMed1996

[The treatment of chronic hepatitis C with interferon in patients infected with the human immunodeficiency virus. The Spanish Group for the Study of Viral Hepatitis in HIV+ Patients].

BACKGROUND: Alfa-interferon (aIFN) is widely recommended for the treatment of chronic hepatitis C (CHC). Hepatitis C virus (HCV) infection is very common in injecting drug users (IDUs), which in Spain represent the large number of HIV-infected persons. Interaction between human immunodeficiency virus (HIV) and HCV in coinfected patients might accelerate the clinical course of HCV-associated liver disease. The efficacy and safety of aIFN therapy in HIV-infected patients with CHC is not well known. PATIENTS AND METHODS: In a multicenter, prospective, open, non randomized and partially controlled study, we compared the efficacy and safety of aIFN therapy in 119 patients with CHC, of whom 90 were HIV-positive and 29 HIV-negative. Interferon was started at 5 mega U tiw for 3 months, followed in responders by 3 megaU tiw for additional 9 months. RESULTS: One hundred seven patients completed the study. A normalization of the aminotransferase values at the end of treatment (complete response, CR) was observed in 26/80 (32.5%) HIV-positive and 10/27 (37.0%) HIV-negative individuals (p = 0.666). Relapses at 12 months of stopping aIFN were seen in 30.8% of HIV-positive subjects and 12.5% of HIV-negatives (p = 0.403). Side effects were uncommon and did not have severity; only one patient required to stop the medication. However, 3 HIV-positive subjects treated with aIFN (3.5% of them) showed an irreversible fall of CD4+ T-cells below half the baseline values. CONCLUSION: HIV-infected patients with CHC seems to respond to aIFN with a similar rate than HIV-negatives. Moreover, the drug is similarly well tolerated in both groups of patients, although a fall of CD4+ T-cells is an unusual side effect of particular relevance observed in HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1996

Immunomodulation by pycnogenol in retrovirus-infected or ethanol-fed mice.

Pycnogenol is a commercial mixture of bioflavonoids that exhibits antioxidative activity. The effects of dietary pycnogenol on immune dysfunction in normal mice as well as those fed ethanol or infected with the LP-BM5 murine retrovirus were determined. The ethanol consumption and retrovirus infection caused abnormalities in the function and/or structure of a broad array of cells involved in humoral and cellular immunity. Pycnogenol enhanced in vitro IL-2 production by mitogen-stimulated splenocytes if its production was suppressed in ethanol-fed or retrovirus-infected mice. Mitogenesis of splenocytes did not show a significant change in mice treated with pycnogenol. It reduced the elevated levels of interleukin-6 produced in vitro by cells from retrovirus infected mice and IL-10 secreted by spleen cells from mice consuming ethanol. Natural killer cell cytotoxicity was increased with pycnogenol treatment.

Adjuvants, Immunologic↗
PubMed1996

Effects of oral propafenone administration before electrical cardioversion of chronic atrial fibrillation: a placebo-controlled study.

OBJECTIVES: Our aim was to evaluate the benefits and risks of administering propafenone before electrical defibrillation for chronic atrial fibrillation. BACKGROUND: In this context, an antiarrhythmic drug-although potentially useful in preventing early recurrence of arrhythmia-could adversely affect the defibrillation threshold and reduce the cardioversion success rate. METHODS: We randomly assigned 100 patients with chronic atrial fibrillation to oral treatment with either placebo (51 patients) or 750 mg/day of propafenone (49 patients) for 48 h before administration of direct current shock. After successful cardioversion, all patients received propafenone therapy and were followed up for 48 h. RESULTS: Before defibrillation, three patients in the propafenone group (6.1%) had reversion to sinus rhythm and one had sustained ventricular tachycardia. Shock efficacy (82.4% vs. 84.4%) and the cumulative effective energy (395 +/- 258 vs. 421 +/- 236 J) were not different between the placebo and propafenone groups. In the propafenone group, 11 patients had their arrhythmia transformed into atrial flutter and required a lower energy level for arrhythmia conversion than did the other patients with continued atrial fibrillation (245 +/- 197 vs. 493 +/- 215 J, p < 0.01); the latter patients showed a trend (p < 0.10) toward higher energy requirements than that of patients who received placebo. The incidence of asymptomatic bradyarrhythmias was higher in the propafenone group (28.9% vs. 7.1%, p < 0.02), but more patients who received placebo had early recurrence of atrial fibrillation (16.7% vs. 0%, p < 0.02). Two days after cardioversion, more patients given propafenone (73.5% vs. 52.9%, p < 0.05) were discharged from the hospital with sinus rhythm. During the in-hospital stay, propafenone was withdrawn from six patients (6.6%) because of side effects. CONCLUSIONS: Propafenone, given before electrical cardioversion for chronic atrial fibrillation does not affect the mean defibrillation threshold or the rate of successful arrhythmia conversion. It decreases the recurrence of atrial fibrillation early after shock, thus allowing more patients to be discharged from the hospital with sinus rhythm.

Administration, Oral↗