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Biomedical subjects

R Valle

Publications and source records attributed to R Valle.

At least 19 recordsLinked to original sources
PubMed2001

Poststreptococcal reactive arthritis in adults: long-term follow-up.

BACKGROUND: Poststreptococcal reactive arthritis (PSReA) is a recognized inflammatory articular syndrome that follows group A streptococcal infection in persons not fulfilling the Jones criteria for the diagnosis of acute rheumatic fever. Characteristic features include nonmigratory arthritis, lack of response to aspirin or nonsteroidal anti-inflammatory agents, and the presence of extra-articular manifestations, including vasculitis and glomerulonephritis. Whether or not patients with PSReA develop carditis is a point of contention. METHODS: We analyzed the clinical features, laboratory findings, response to therapy, and outcome in patients diagnosed with PSReA between 1983 and 1998 and observed through April 2000. All patients were contacted, reexamined, and repeat antistreptolysin, rheumatoid factor, C3 and C4 complement components, and echocardiograms were performed. RESULTS: Seventeen patients (4 men and 13 women) were included. All were of low socioeconomic status. All patients had acute severe arthritis that began shortly after a sore throat episode. Extra-articular involvement including tenosynovitis, vasculitis, and glomerulonephritis was relatively common. More importantly, none exhibited clinical and/or echocardiographic evidence of cardiac involvement. Longterm antibiotic therapy was not given. CONCLUSION: Cardiac involvement did not occur in this group of patients with PSReA. Prolonged prophylactic antibiotic therapy may not be required for adult patients presenting with PSReA.

Adolescent↗
PubMed2001

[Heart failure in nursing homes: prevalence, hospitalization, compliance to guidelines].

BACKGROUND: The prevalence of heart failure, the hospitalization rates for DRG 127 and the adherence to the recommendations included in the guidelines on pharmacological treatment among very old persons are poorly known. METHODS: We screened 141 very old subjects (75% females, aged 87+/-4 years), living in 2 nursing homes. Heart failure was defined according to clinical criteria and on the basis of administrative databases and chart reviews. The latter were also used to collect data on hospitalization rates and pharmacological therapy. RESULTS: We found that: 1) 23% of the subjects were affected by heart failure; 2) with regard to such patients, 26 hospital admissions for DRG 127 occurred in 1999 (18 admissions and 8 readmissions; 3) ACE-inhibitors have been prescribed to 54% of patients with a diagnosis of heart failure. CONCLUSIONS: Heart failure affects a huge number of very old persons living in nursing homes. These patients have high hospitalization rates for DRG 127. The adherence to the recommendations included in the guidelines on the pharmacological therapy for very old persons is poor.

Aged↗
PubMed2001

Cultural assessment in bioethical advocacy--toward cultural competency in bioethical practice.

The continued diversification of the U.S. population poses increasing challenges for bioethical advocates (e.g., ethicists, physicians, nurses, social workers, psychologists, surrogates, researchers, and lawyers), especially those serving rapidly expanding and culturally varied populations. The issue from the bioethics perspective is that the members of ethnically diverse groups often bring different normative expectations and their own preferred decision-making formats to the bioethics table. For example, some advocates will encounter a "collectivity," or the family-as-a-whole rather than the individual, as a decision maker. In other instances, they may encounter cultural groups whose members (or some of whose members) will value the principle of beneficence more than personal autonomy. Moreover, such value-based challenges are likely to continue since forecasters predict that diversification will actually quicken in the United States throughout the next five decades. In the face of these changes in the bioethical climate, advocates must be prepared to strengthen their cultural assessment skills. Taking a multidimensional approach to the problem yields a four-point cultural assessment model to help advocates handle the great diversity of outlook and orientation among their culturally diverse clientele.

Beneficence↗
PubMed1999

Assessment of student performance in problem-based learning tutorial sessions.

OBJECTIVES: To assess student performance during tutorial sessions in problem-based learning (PBL). DESIGN: A 24-item rating scale was developed to assess student performance during tutorial sessions in problem-based learning (PBL) as conducted during the pre-clinical years of Medical School at the National Autonomous University of Mexico. Items were divided into three categories: Independent study, Group interaction and Reasoning skills. Fourteen tutors assessed 152 first and second-year students in 16 tutorial groups. An exploratory factor analysis with an Oblimin rotation was carried out to identify the underlying dimensions of the questionnaire. SETTING: Medical School at the National Autonomous University of Mexico. SUBJECTS: Medical students. RESULTS: Factor analysis yielded four factors (Independent study, Group interaction, Reasoning skills, and Active participation) which together accounted for 76.6% of the variance. Their Cronbach reliability coefficients were 0.95, 0.83, 0.94 and 0. 93, respectively, and 0.96 for the scale as a whole. CONCLUSIONS: It was concluded that the questionnaire provides a reliable identification of the fundamental components of the PBL method as observable in tutorial groups and could be a useful assessment instrument for tutors wishing to monitor students' progress in each of these components.

Adult↗
PubMed1998

Characterization of MLH1 and MSH2 alternative splicing and its relevance to molecular testing of colorectal cancer susceptibility.

The phenomenon of alternative splicing in the DNA mismatch repair genes MLH1 and MSH2 was extensively investigated by coupled reverse transcription-polymerase chain reaction in different human tissues, including 42 mononuclear blood cell samples--31 obtained from familial colon cancer patients or their at-risk relatives and 11 from healthy blood donors--7 normal colonic mucosae, 4 established human cancer cell lines, 8 colorectal tumors, and one sample each of ileum, liver, muscle, thymus, breast, and EBV-transformed lymphoblasts. Several isoforms were observed for each gene. Products of MLH1 alternative splicing included mRNAs lacking alternative exons 6/9, 9, 9/10, 9/10/11, 10/11, 12, 16, and 17. For MSH2, products lacking exons 5, 13, 2 through 7, and 2 through 8 were identified. The levels of expression were found to vary among different samples. All isoforms were found in a relevant fraction (43-100%) of the mononuclear blood cell samples, as well as in other tissues. The splicing variants were also detected in normal colonic mucosa, with the exceptions of the MLH1 -6/9 and -10/11 and the MSH2 -13 isoforms. Germline mutations of MLH1 and MSH2 confer constitutional predisposition to the development of colorectal cancer and other neoplasms. A substantial proportion of the mutations identified so far involve alterations of the normal splicing process. Knowledge of the existence of multiple alternative splicing events, not caused by genomic DNA changes, is important for the evaluation of the results of molecular diagnostic tests based on RNA analysis.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Loss of heterozygosity at the 5,10-methylenetetrahydrofolate reductase locus in human ovarian carcinomas.

The high-affinity folate-binding protein (FBP) is primarily involved in the uptake of the 5-methyltetrahydrofolate, and its expression may be physiologically regulated by the intracellular folate content. The overexpression of FBP on the cell surface of ovarian carcinoma cells may be responsible for an increased folate uptake. We tested the hypothesis of the existence of a defect in the 5, 10-methylenetetrahydrofolate reductase (MTHFR) in ovarian tumours that could cause reduced intracellular regeneration of the 5-methyltetrahydrofolate and induce increased FBP expression. No sequence mutations were found in the MTHFR gene, but allelic deletions of this gene were frequently detected in ovarian tumours (59%). Chromosomal losses appeared to be confined to the 1p36.3 region to which the MTHFR gene maps. Although it cannot be stated that MTHFR is the target gene of the chromosomal loss involving the 1p36.3 region, a correlation between loss of heterozygosity at this locus and decrease in MTHFR activity was shown, suggesting a role of these allelic deletions in generating a biochemical defect in folate metabolism. Further studies are needed to assess further the relationship between MTHFR and FBP overexpression, but the demonstration of the alteration of a key metabolic enzyme of the folate cycle in a subset of human ovarian tumours is in accordance with the hypothesis of an altered folate metabolism in these neoplasias and might be exploited for therapeutic purposes.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed1995

Ouabain-inhibiting activity of aldosterone antagonists.

It has been suggested that endogenous substances (known as ouabain-like factors, OLF), secreted from the central nervous system in response to salt and water retention, inhibit the cell membrane Na+/K+ pump in the renal tubules and reduce sodium reabsorption. However, by also acting upon vascular smooth muscle cells, they may induce cell Na+ and Ca++ accumulation, vasoconstriction and systemic hypertension. Recently, an endogenous Na+/K+ pump inhibitor was isolated from human plasma; this inhibitor is indistinguishable from the cardiac glycoside ouabain based on biochemical and immunological criteria. Its plasma concentration is close to the therapeutic range for ouabain (around 0.4 nmol/L). Since plant ouabain promotes natriuresis, vasoconstriction, and hypertension; endogenous ouabain may therefore control extracellular fluid volume and blood pressure. The highest plasma concentrations of endogenous ouabain and OLF were found in congestive heart failure, aldosterone producing adenoma, human and animal models of volume expanded hypertension (reduced renal mass and DOCA-salt hypertension), and in Milan hypertensive rats (MHS). Aldosterone antagonists (canrenone and canrenoate) exert both agonist and antagonist effects on the digitalis receptor site of the Na+/K+ pump. They are effective antihypertensive agents in animal models of hypertension sustained by OLF (reduced renal mass-Na+ and DOCA-salt hypertension in rats). Moreover, in a subgroup of essential hypertensives, 4 weeks of canrenoate administration reduced blood pressure, heightened red blood cell Na+/K+ pump activity, and antagonized ouabain-induced vasoconstriction. None of these effects was seen in the other hypertensives. These data suggest that aldosterone antagonists stimulate the Na+/K+ pump inhibited by endogenous ouabain and exert their antihypertensive action at least in part through this mechanism.

Animals↗
PubMed1995

Kinetic properties of erythrocyte Na+-Li+ and Na+-H+ exchange in hypertensive patients.

OBJECTIVE: To ascertain the relationships between the kinetic properties of erythrocyte Na+-H+ exchange [maximum kinetic energy (Vmax), Michaelis constant (Km) for internal H+ and Hill's coefficient], Na+-Li+ (Vmax and Km for external Na+), and metabolic parameters in normotensive controls and hypertensive subjects. MATERIALS AND METHODS: Na+-H+ exchange was measured as the Na+ influx driven by intracellular H+, and Na+-Li+ exchange as the Li+ efflux driven by extracellular Na+, in erythrocytes from normotensive (n = 59) and hypertensive (n = 93) subjects. RESULTS: In comparison with normotensives, the hypertensives had a higher Vmax for Na+-Li+ and Na+-H+ exchange, a higher Km for external Na+ for Na+-Li+ exchange and a lower reduced Hill's number for Na+-H+ exchange. Vmax values for Na+-Li+ and Na+-H+ exchange were significantly correlated, as were Km values for internal H+ for Na+-H+ exchange and Km for external Na+ for Na+-Li+ exchange. Insulin resistance and beta-cell function indices were higher in the hypertensives than the normotensives. Upon stepwise multiple regression analysis, Vmax for Na+-Li+ exchange was correlated significantly and independently with Km for external Na+ and with the insulin resistance index, while Km for external Na+ was correlated with Km for internal H+, Vmax for Na+-H+ exchange and mean blood pressure. Vmax and Hill's coefficient for Na+-H+ exchange were correlated only with mean blood pressure. CONCLUSIONS: The demonstration of functional correlations between the kinetic properties of Na+-H+ and Na+-Li+ exchange provides further evidence that erythrocyte Na+-Li+ exchange is a functioning mode of Na+-H+ exchange, which is affected by insulin resistance.

Adult↗
PubMed1994

Fish oils and their possible role in the treatment of cardiovascular diseases.

The multifactorial origin of arteriosclerotic cardiovascular diseases is well recognized. It recently has been shown that n-3 fatty acids (FA), contained in fish oils, may correct some of the most important cardiovascular risk factors and may interfere with key steps in the formation of the atherosclerotic plaque. These findings have raised such interest that many reports have been published with somewhat conflicting results. In hypertensive patients, randomized controlled studies have confirmed that n-3 FA may reduce systolic blood pressure by 5 mmHg and diastolic by 4 mmHg. The decrease in pressure, which could be larger if dietary sodium restriction is added, is probably due to the shift of balance between vasoconstrictive and vasodilator eicosanoids toward vasodilatation. n-3 FA correct endogenous hypertriglyceridemia, but the effects on low-density lipoprotein and high-density lipoprotein cholesterol are less clear cut, since an increase in low-density lipoprotein and a decrease in high-density lipoprotein may be observed in selected patients. As far as the glucose metabolism in patients with diabetes mellitus is concerned, inhibition of the beta cell by n-3 FA has been reported. n-3 FA reduce platelet aggregation, blood viscosity, plasma levels of fibrinogen, PF4 and beta-thromboglobulin and increase capillary flow and red cell membrane fluidity, but their long-term effects on cardiovascular mortality are largely unknown. Medium-term studies, however, have shown a decreased risk of myocardial reinfarction and of restenosis after percutaneous transluminal coronary angioplasty with n-3 FA supplementation. Pure, highly concentrated triglycerides and ethyl esters of n-3 FA are available and will allow further investigations on the dose-response ratio in humans.

Animals↗
PubMed1994

Lung abscess due to Streptococcus mitis: case report and review.

Streptococcus mitis is a bacterium traditionally regarded as a normal commensal of the oropharynx, skin, and intestinal and genital tracts. To our knowledge, we describe the first case of bilateral lung abscesses caused by S. mitis in an immunocompetent host. The abscesses were successfully treated with clindamycin and gentamicin. Our case illustrates that S. mitis should be considered a cause of pulmonary abscesses.

Clindamycin↗
PubMed1994

Malignant pleural effusion from prostatic adenocarcinoma resolved with hormonal therapy.

A 73-year-old man presented with dyspnea, right-sided pleural effusion, and bilateral pulmonary infiltrates. The pleural fluid revealed adenocarcinoma cells that stained positively for prostatic specific antigen (PSA), which confirmed this uncommon metastatic involvement from prostate cancer. The dyspnea, effusion, and infiltrates disappeared after therapy with flutamide and leuprolide was started. This report demonstrates both the usefulness of immunocytochemical staining for PSA in ascertaining the origin of malignant pleural effusion in men and the effectiveness of the aforementioned endocrine therapy in such setting.

Adenocarcinoma↗