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Biomedical subjects

E Ramos

Publications and source records attributed to E Ramos.

At least 127 records · Page 7Linked to original sources
PubMed1994

Increased antibody responsiveness to blood transfusions in pediatric patients.

Heightened immune responsiveness has been proposed as one of the reasons underlying suboptimal renal transplant results in very young children or African American recipients. Because multiple factors influence graft outcome, it has been difficult to provide experimental evidence to confirm or refute this suggestion. In the present study we measured IgG antibodies with confirmed HLA specificity produced in response to blood transfusions. The patients evaluated were renal transplant candidates who had not had previous pregnancies or transplants. The overall incidence of HLA sensitization was 12%. Age was the most influential factor in sensitization: patients < 20 years old were 4-5 times as likely to produce anti-HLA antibodies than patients > 20 (P = 0.0018). Female patients were also high responders. However, this was explained by the higher proportion of children among nulliparous female patients rather than by differences in gender. In contrast, the antibody response of black and white recipients was similar. The antibody levels in most patients were low and decreased significantly with time. We conclude that the immunoregulatory influences in patients < 20 years old favor the production of anti-HLA antibodies in response to blood transfusions, a fact that may explain some clinical observations in pediatric transplant recipients.

Adolescent↗
PubMed1994

The impact of arterialization on prostanoid generation after liver transplantation in the rat.

Arterial reconstruction is not applied in most studies of hepatic transplantation. Differences in some parameters related to the microcirculatory status, depending on whether the graft has been subjected to both arterial and venous or only venous reconstruction have been demonstrated. We have evaluated whether arterialization has an effect on the production of inflammatory event-related mediators such as eicosanoids and oxygen free radicals. For this purpose, we have measured tissue eicosanoid levels, lipid peroxidation, and superoxide dismutase activity in livers subjected to arterial and venous or only venous reconstruction. No changes were observed in lipid peroxidation or superoxide dismutase activity when single and double revascularization were compared. Prostacyclin and thromboxane metabolites showed increased levels after 24-hr preservation when only venous reconstruction was carried out. In contrast, these metabolites remained unaltered when double revascularization was performed. This result suggests that eicosanoid metabolism is altered only when venous reconstruction was employed, and this fact can help explain microcirculatory changes reported in this experimental model of liver transplantation.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

[Acute abdomen due to cytomegalovirus in AIDS patients. Apropos 2 cases].

Two cases of acute abdomen--because of acute appendicitis and paralytic ileus--due to cytomegalovirus infection in AIDS patients are reported. In both patients evolution was subacute and cytomegalic inclusions were seen in the histologic examination of the surgical samples. The two patients died after surgery. The possibility of cytomegalovirus infection must be kept in mind in AIDS patients who undergo urgent abdominal laparatomy and early treatment should be instituted.

AIDS-Related Opportunistic Infections↗
PubMed1994

Comparison of the immune response against Mycobacterium tuberculosis antigens between a group of patients with active pulmonary tuberculosis and healthy household contacts.

The mycobacterial antigens and the factors related to protection for the development of active tuberculosis are not known. In a natural model of tuberculosis, we studied 10 patients with active pulmonary tuberculosis (non-protective immune response) and 38 healthy household contacts (protective immune response). We tested the lymphocyte proliferative response by T cell Western blotting to eight different antigen fractions and to two purified mycobacterial antigens of 30 and 64 kD. Patients with active tuberculosis recognized fractions with molecular weights of 80-114, 60-80, 28-41 and 14-19 kD. Household contacts recognized the same fractions except the 14-19 kD. The response to the 64-kD antigen was not significantly different between groups. In contrast, 10% of the patients with active tuberculosis and 73% of the household contacts responded to the 30-kD antigen. The humoral response against the 30-kD antigen by ELISA showed a significantly higher production of antibodies in tuberculosis patients compared with household contacts. We conclude that patients with active pulmonary tuberculosis develop an immune response characterized by poor proliferative response to the 30-kD antigen with a strong humoral response, whereas the opposite occurs in healthy subjects infected by Mycobacterium tuberculosis.

Antibodies, Bacterial↗
PubMed1994

Measured femoral density by dual-energy X-ray absorptiometry as a function of rotation.

The use of projectional techniques to evaluate bone density of the proximal femur has the potential to be adversely affected by rotation along the head/condyle axis, due to the complex geometry of the region being examined. To experimentally investigate the magnitude of variation attributable to rotation, the bone density of a cadaveric femur, placed in a water bath to simulate soft tissue, was measured as a function of rotation by using a dual-energy x-ray absorptiometry (DXA) system. It was found that 10 to 15 degrees of rotation was the minimum deviation from the baseline of the femoral head perpendicular to the x-ray beam required to produce statistically significant (P = .95) changes in measured bone density. The magnitude of the variation at these rotations ranged from 2.5% for the trochanter to 5.0% for the femoral neck. Even though variation along the axis described is difficult to precisely control in the clinical setting, the magnitude of density errors attributable to these variations should not adversely affect the utility of projectional density measurement techniques.

Absorptiometry, Photon↗
PubMed1993

Delta-aminolevulinic acid transport in Saccharomyces cerevisiae.

1. This work represents the first approach to characterize the transport system of haem pathway precursors, such as delta-aminolevulinic acid (ALA), in two strains of Saccharomyces cerevisiae, a wild type, D27, and a HEM R+ mutant. 2. ALA transport occurs unidirectionally by a sole active system with an apparent KM of 0.10 mM, at the optimum pH of 5.0. ALA uptake is influenced by both the carbon and nitrogen source; this suggests a rather complex regulation mechanism. 3. This transport is not mediated by the general amino acid permease (GAP). 4. ALA uptake is strongly inhibited by compounds harboring a methyl-amine terminus suggesting that this group is essential for ALA transport; however, the electric environment of the carboxylic group may be also important for the interaction between ALA and its transporter active site. 5. We have found differences in ALA transport which would indicate a different regulation mechanism for this system in both strain cells.

Aminolevulinic Acid↗
PubMed1993

Quercetin and the mutagenicity of wines.

Various studies have shown the mutagenicity of red wine. The major mutagens identified in red wine have been flavonoids, i.e. rutin and its aglycone quercetin. Besides flavonoids, however, it has recently been reported that H2O2 may account for the mutagenicity of red wine in the L-Arabinose resistance test. In the present study we report on the role of flavonoids in the mutagenicity of red wine in the Ames assay. Different wines from Portugal and Spain have been tested after concentration in XAD-2 columns in strains TA98 and TA104 of Salmonella typhimurium concurrently with the determination of the respective content of quercetin by HPLC. A similar approach was used for pilot scale productions of red wines. In all cases quercetin could be demonstrated as the major mutagen in red wines. The levels of quercetin in finished wines and during the wine-making process showed a good fit with the levels of mutagenicity detected. Catalase had no effect whatsoever on the mutagenicity of wines in both TA98 and TA104. These results do not rule out a role for H2O2 in the mutagenicity of wines, detected in other genetic end-points, because H2O2 can be formed from the auto-oxidation of quercetin.

Animals↗
PubMed1991

Double-blind comparison of levocabastine eye drops with sodium cromoglycate and placebo in the treatment of seasonal allergic conjunctivitis.

The efficacy and tolerance of topical administration (one drop in each eye q.i.d.) of levocabastine (0.5 mg/ml) was compared with that of sodium cromoglycate (20 mg/ml) and placebo in a 4-week double-blind trial in patients with seasonal allergic conjunctivitis. The investigator rated the treatment as globally good or excellent in significantly more patients treated with levocabastine (89%) than with cromoglycate (67%, P = 0.03) or placebo (48%, P = 0.007). The patients felt that the treatment was more efficacious in 95% (levocabastine), 35% (cromoglycate) and 36% (placebo) of the cases in which they had taken previous antiallergic medication. Total symptom severity according to the patients' diary data was consistently lower with levocabastine than with cromoglycate or placebo for all ocular symptoms. The difference was mainly apparent at the beginning of treatment. The percentage of symptom-free days was higher in the levocabastine group (53%) than in the cromoglycate (31%, P = 0.02) and the placebo group (34%, P = 0.08). Particularly at high-pollen days, levocabastine was superior to cromoglycate in eliminating moderate or severe symptoms. Adverse effects did not occur more frequently with levocabastine or cromoglycate than with placebo. It is concluded that levocabastine is an efficacious, fast-acting and well-tolerated drug in the management of seasonal allergic conjunctivitis.

Adolescent↗
PubMed1990

Vibroacoustic stimulation and fetal behavioral state in normal term human pregnancy.

Vibroacoustic stimulation may affect human fetal behavior. Continuous graphic records of simultaneous ultrasonographic observations of fetal activities and electronic fetal heart rate tracings of 30 normal term fetuses were examined visually for the occurrence of behavioral state 30 minutes before and after 3 seconds of vibroacoustic stimulation. After vibroacoustic stimulation, the total time spent in state 1 decreased significantly, that spent in state 4 increased significantly, and times spent in state 2 and indeterminate state (no state established for at least 3 minutes) were unchanged. No fetus exhibited state 3 before or after vibroacoustic stimulation. State 4 occurred in 22 fetuses after vibroacoustic stimulation with a duration of at least 30 minutes in four fetuses, and was noted in all fetuses in pre-vibroacoustic stimulation state 1 and 11 of 16 fetuses in pre-vibroacoustic stimulation state 2. Fetal heart rate accelerations occurred within 10 seconds after vibroacoustic stimulation in 94% of the fetuses studied regardless of their prior behavioral state. The variation in the onset and duration of behavioral state responses in most fetuses after vibroacoustic stimulation may depend on previous behavioral state and could be important for interpretation of antenatal assessment that uses this stimulus.

Acoustic Stimulation↗
PubMed1990

Benign myoclonic epilepsy of infancy.

We present a case of benign myoclonic epilepsy of infancy and analyze the characteristic electroclinical findings. We wish to emphasize the usefulness of recognizing this entity among myoclonic epilepsies in children to enable early treatment and to obtain a good prognosis.

Child, Preschool↗