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Biomedical subjects

G Perez

Publications and source records attributed to G Perez.

At least 55 records · Page 3Linked to original sources
PubMed1994

TRPM-2 gene expression in normal rat ventral prostate following castration and exposure to diethylstilbestrol, flutamide, MK-906 (finasteride), and coumarin.

TRPM-2, not normally expressed in the rat ventral prostate, has been identified as an important genetic marker of castration-induced apoptotic cell death. It is not known whether other agents capable of causing growth inhibition of the rat ventral prostate also induce TRPM-2 expression. To investigate this further, 270 mature Sprague-Dawley rats were randomized into one of six groups: control, castration, diethylstilbestrol (DES), flutamide, MK-906 (finasteride), or coumarin. Five rats per group were sacrificed on days 1, 3, 5, 7, 10, and 21. Serum testosterone, body weights, and prostate weights were determined at each time point. The ventral prostate was removed and cellular RNA extracted. Northern blot analysis using cDNA probes for TRPM-2 and gamma-actin were performed at each time point. Only DES significantly decreased rat weights. DES and castration reduced serum testosterone to undetectable levels by the next day. Flutamide caused a 3.0- to 4.5-fold increase in serum testosterone above control. Coumarin and MK-906 did not affect serum testosterone levels. DES and castration reduced prostate weights to 20% and 6% of control, respectively, while inducing TRPM-2 expression to a maximum on day 5 of the experiment. DES induced TRPM-2 expression over a longer duration than did castration, suggesting that more than just the decrease of serum testosterone to castrate levels plays a role in the expression of TRPM-2. MK-906, coumarin, and flutamide reduced prostatic weights to a lesser extent (50%, 63%, 71% of control, respectively), but these agents did not induce TRPM-2 expression at any time during the experiment. TRPM-2 expression in the rat ventral prostate does not correlate simply with catabolic effects on the prostate.

Animals↗
PubMed1994

Stimulation with a monoclonal antibody (mAb4E4) of scavenger receptor-mediated uptake of chemically modified low density lipoproteins by THP-1-derived macrophages enhances foam cell generation.

mAb4E4, a murine monoclonal antibody that is specific for acetylated LDL and malondialdehyde-treated LDL, binds specifically to modified LDL present in human atherosclerotic lesions. It is directed against an epitope that is poorly exposed in delipidated and solubilized apolipoprotein B-100 from modified LDL. mAb4E4, as well as its F(ab')2 and Fab fragments, enhanced the uptake of both acetylated LDL and malondialdehyde-treated LDL by THP-1-derived macrophages resulting in a sixfold increase of cytoplasmic cholesteryl ester levels. The increased uptake of modified LDL/mAb4E4 complexes did not occur via the Fc receptor and did not depend on aggregation of modified LDL particles. However, their uptake was inhibited by blocking the scavenger receptors with fucoidin or by downregulation of receptor expression with endotoxins or interferon-gamma, indicating that their uptake is mediated via these receptors. Thus, generation of autoimmune antibodies against modified LDL and subsequent endocytosis of soluble modified LDL/antibody complexes via scavenger receptors may enhance foam cell generation. This mechanism may contribute to the progression of atherosclerotic lesions.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1994

Detection of hepatitis C virus RNA in hemodialysis patients.

The clinical significance of the high prevalence of antibodies to hepatitis C virus (HCV) in dialysis patients remains undefined. In order to assess the relationship between seropositivity and potential infectivity, 63 patients undergoing maintenance hemodialysis were evaluated between April and May 1990. The mean duration of maintenance hemodialysis was 45 mo (range, 13 to 144). Eighty-two percent (52 of 63) had received blood transfusions, and 16% (10 of 63) had a history of iv drug abuse. Serum samples were analyzed by HCV-cDNA polymerase chain reaction; antibodies to HCV structural (core) and nonstructural regions NS3 and NS4 were determined by enzyme immunoassay. Specimens repeatedly reactive for anti-HCV and HCV-RNA-positive samples were tested by HCV MATRIX dot immunoblot assay and HBV-DNA PCR. Twenty-five percent (16 of 63) were anti-HCV-positive. Of the 16 anti-HCV-positive patients, HCV-RNA was detected in 5 (31%) with the NS3 primers and in 12 (75%) with 5'-noncoding primers. Among the anti-HCV-negative patients, HCV-RNA was detected in 2 (4.3%) of 47 patients. Eleven of the 18 patients with HCV infection (anti-HCV and/or HCV-RNA-positive) had evidence of additional present or past viral infections (human immunodeficiency virus and/or hepatitis B virus). In summary, HCV-RNA is present in at least 75% of anti-HCV-positive patients, suggesting that they may be infectious. The detection of HCV-RNA in anti-HCV-negative patients may indicate early or chronic HCV infection not detected by current antibody assays or the inability of these patients to mount or sustain a significant antibody response.

Adult↗
PubMed1993

Blood conservation techniques for cardiac surgery: a survey of French centres.

A survey resulting from a partnership between CECEC (Centre d'Etudes en Circulation Extra-Corporelle) and Laboratoires Hoechst, France was carried out amongst all French adult cardiac surgery centres. The aim of this study was to investigate the various strategies used to decrease blood loss during open-heart surgery. Due to an exceptionally high response rate, we are able to report the current practice of French cardiac centres which account for 75% of open-heart adult surgery. The three most interesting strategies for blood conservation appear to be haemodilution, blood salvage from the extracorporeal circuit and previously deposited autologous blood transfusion, yet the three methods which are predominantly used are haemodilution (92.7%), aprotinin therapy (87.8%) and blood salvage from the extracorporeal circuit (82.9%).

Aprotinin↗
PubMed1993

Risk assessment for human immunodeficiency virus among pregnant Hispanic adolescents.

Inner-city adolescents are believed to be at increased risk for HIV infection because of their high-risk behaviors, and black and Hispanic teenagers may be at greatest risk as a consequence of these behaviors and inadequate AIDS education. In the present paper, the HIV risk status of pregnant Hispanic adolescents presenting for prenatal care to an inner-city municipal outpatient clinic located in New York City was assessed. The assessment consisted of a confidential structured interview. Based on known adult risk factors, adolescents were identified as being at increased risk or low risk. One-third of the 87 teenagers were identified as being at increased risk for HIV infection. Nobody reported symptoms suggestive of AIDS, had had a transfusion, or reported use of intravenous drugs or crack cocaine. Sexual risk-taking behavior was the most common factor that increased HIV risk. Sixteen adolescents were at increased risk solely because of a sexually transmitted disease and seven others reported an STD with at least one other risk factor. Although 86% of the pregnant teenagers reported the risk-taking behavior of substance use by self or partner, only four were at increased risk based on this factor alone. However, many adolescents were unaware of their partners' past substance use and sexual history and, therefore, may have underestimated their own risk. Birthplace (United States vs. foreign born) and nationality (Puerto Rican vs. non-Puerto Rican Hispanic) were significantly associated with the adolescents' HIV risk assessment via an interaction effect. None of the adolescents had previously considered themselves to be at increased risk for HIV infection. The overwhelming majority who were at increased risk declined referral for further counseling or testing. It is recommended that pregnant Hispanic adolescents be assessed for HIV risk and receive risk reduction counseling as part of their general health care.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Normothermic cardioplegia: is aortic cross-clamping still synonymous with myocardial ischemia?

The enthusiastic clinical reports on normothermic blood cardioplegia contrast with the paucity of data on the myocardial metabolic effects of this technique. The present study was therefore designed to assess whether normothermic blood cardioplegia really provides an aerobic environment during aortic cross-clamping. Thirty-one patients undergoing coronary (16 patients), valve (13 patients), and transplantation (2 patients) procedures were given continuous normothermic blood cardioplegia through the coronary sinus. Myocardial metabolism was assessed either immediately before aortic unclamping (16 patients) by collecting blood simultaneously from the cardioplegia infusion line and the aortic effluent or during reperfusion (15 patients) by collecting blood simultaneously from the radial artery and the coronary sinus. All samples were assayed for markers of anaerobiosis (blood gases, lactates), leukocyte activation (elastase), and lipid peroxidation (malondialdehyde, vitamin E). At the end of arrest, oxygen extraction was low, whereas the production of lactates was small, thereby suggesting the efficacy of normothermic blood cardioplegia in maintaining a predominantly aerobic metabolism. This was confirmed by postarrest data, as oxygen extraction measured immediately after cross-clamp removal was unchanged from prearrest values, whereas lactate metabolism yielded transient and limited production followed by prompt recovery of normal extraction patterns. There was no release of elastase from the myocardium, which suggests adequate protection of the coronary endothelium from ischemic injury and the related increase in leukocyte activation. Likewise, postarrest coronary sinus concentrations of malondialdehyde and vitamin E were identical to the respective arterial concentrations, thereby ruling out the occurrence of intramyocardial lipid peroxidation at the time of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Case report: distinctive immune abnormalities in a patient with procainamide-induced lupus and serositis.

To gain insight into the immunopathogenesis of drug-induced autoimmune disorders, lymphocyte and immunoglobulin distributions and cytokine levels were monitored in the peripheral blood and pleural fluid of a patient with procainamide-induced lupus and pleural effusion. Approximately 80% of the B cells in both compartments were CD5+ compared to 10% to 25% in normal adults. CD4/CD8 ratio and percentage CD4 were normal in peripheral blood. Serum levels of IgG (particularly IgG2), IL-6, and soluble IL-2R were slightly elevated, and those of IgA were significantly elevated compared to normal controls. Analysis of the pleural effusion revealed an increased CD4/CD8 ratio because of an increased percentage of CD4+CD29+ helper memory T cells, lack of expression of the resting B-cell marker CD21, immune complex deposition and complement consumption, increased relative levels of ANA, abnormally high levels of IL-6 and soluble IL-2R, and detectable levels of IL-1b, IFN-g and TNF-a. These observations provide evidence for the involvement of CD5+ B cells and differential helper T-cell activity in procainamide-induced lupus and for an association between local lymphocyte activation and organ pathology.

Aged↗
PubMed1992

Comprehensive evaluation of acute immunological changes induced by cuprophane and polysulfone membranes in a patient on chronic hemodialysis.

We have investigated the acute changes in cytokine gene expression patterns and immune status in vivo and ex vivo in a patient on chronic hemodialysis with cuprophane membranes before and after two hemodialysis sessions with either cuprophane or polysulfone membranes. Results show that both dialyzer membranes have differential acute effects on the immune system and that the concomitant use of reverse-transcriptase-coupled polymerase chain reaction, solid-phase and radioimmunoassays, and flow-cytometric analysis may be useful in the longitudinal assessment of patients on chronic hemodialysis.

Biocompatible Materials↗
PubMed1991

Identification of H+/K(+)-ATPase alpha,beta-heterodimers.

Glutaraldehyde treatment of the C12E8 solubilized H+/K(+)-ATPase crosslinks the catalytic subunit with an apparent molecular mass of 94 kDa in SDS polyacrylamide gels into two Coomassie stained particles migrating at approx. 147 and 173 kDa. The subunit composition of these particles was determined from the comparative distribution of FITC fluorescence, wheat germ agglutinin and anti-beta antibody reactivity in control and crosslinked preparations. FITC exclusively labelled the catalytic monomer of the native preparation and its fluorescence was initially distributed into two broad bands centered at approx. 147 and 173 kDa after crosslinking. These fluorescent bands coincided with the Coomassie stained particles. A glycoprotein(s) detected by wheat germ agglutinin reactivity was present in diffuse areas between 65 and 86 kDa and 95 to 134 kDa in the control preparation. This area was also labelled by the anti-beta antibodies. With crosslinking, the distribution of the wheat germ agglutinin reactive protein and anti-beta antibodies coincided with the crosslinked particles labelled by FITC. The presence of both the catalytic monomer and the beta subunit glycoprotein in the crosslinked particles indicated that these proteins were closely associated in the C12E8 solution. This suggests that the minimal structural particle of the H+/K(+)-ATPase is an alpha,beta-heterodimer.

Adenosine Triphosphatases↗
PubMed1991

Comparison of the amino acid sequences of the lectins from seeds of Dioclea lehmanni and Canavalia maritima.

The amino acid sequences of the major lectins from the seeds of Dioclea lehmanni and Canavalia maritima were determined by DABITC/PITC microsequence analysis of peptides derived from the proteins by enzymatic digestions with trypsin, chymotrypsin and the protease from S. aureus V8. These sequences were found to be very similar to those of the lectins from Dioclea grandiflora and Canavalia ensiformis (Con A). The D. lehmanni lectin was unusual amongst legume lectins in that it contained a single Cys.

Amino Acid Sequence↗
PubMed1991

Hispanic adolescent pregnancy testers: a comparative analysis of negative testers, childbearers and aborters.

Fifty-six Hispanic adolescents who requested a pregnancy determination at a municipal outpatient adolescent clinic participated in a comparative study of negative testers, childbearers, and aborters. The study's purposes were to assess differences between negative and positive pregnancy testers and to evaluate the pregnancy resolution decision-making process of positive testers. Data were collected using a two-part structured interview administered prior to and following knowledge of pregnancy test results. Results indicated that negative and positive pregnancy testers were similar in all areas evaluated. However, positive testers were slightly older and had higher self-esteem than negative testers. Of the 36 positive testers, 29 chose to deliver and keep the baby. None of the adolescents chose adoption. Adolescents were consistent in their pregnancy resolution decision before and after knowledge of pregnancy test results. The pregnant adolescents considered themselves to be the most influential person in the decision-making process. There were no significant differences between the childbearers and the aborters, although the former demonstrated higher self-esteem and greater religiosity. Most of the teenagers were at risk for unintended pregnancy; therefore, subsequent family planning counseling efforts should be directed at this population.

Abortion, Induced↗
PubMed1991

Interferon alpha treatment of accelerated-phase chronic myeloid leukemia in relapse after bone marrow transplantation: a case with complete cytogenetic and molecular remission.

We describe here a patient with Philadelphia-positive chronic myeloid leukemia who had a hematologic and cytogenetic relapse after bone marrow transplantation. A diagnosis of accelerated phase was made when an additional malignant clone was detected. This clone was probably derived from the primitive Philadelphia clone, with duplication and rearrangement of the Philadelphia chromosome. The patient was treated with interferon alpha 2a and experienced a complete cytogenetic and molecular remission, with full reconstitution of the donor marrow.

Bone Marrow Transplantation↗