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Biomedical subjects

V Valls

Publications and source records attributed to V Valls.

At least 19 recordsLinked to original sources

Usefulness of pp65 antigenemia for the early diagnosis of cytomegalovirus disease in patients with AIDS.

An observational cohort study was performed to assess the effectiveness of a cytomegalovirus antigenemia (CMV-Ag) assay designed to predict clinical CMV disease in patients with AIDS. Eighty-six HIV-infected patients with CD4+ cell counts of < 100/mm3, positive CMV IgG, and no previous CMV disease were enrolled. Thirty-eight (44%) patients had at least one positive CMV antigenemia test, ten of whom eventually developed CMV focal disease. CMV disease was diagnosed in 13 (15%) patients. The CMV antigenemia assay was positive in ten of these 13 patients. Using a cut-off value of five positive cells in every 150,000 leukocytes sampled, the CMV antigenemia assay had a positive predictive value of 89% and a negative predictive value of 94%. The median time from the first positive CMV antigenemia test to the onset of CMV disease was 102 days. CMV disease probability at 6 months in patients with a CMV antigenemia value > or = 5 was 77.8% versus 6% in patients with CMV antigenemia value < 5 (log-rank test = 48.345; P < 0.001). Several independent factors were associated with the development of CMV disease: CMV antigenemia > or = 5 cells (hazard ratio: 20.44), CD4+ count < or = 25/mm3 (HR: 3.12), and sexual transmission of HIV infection (hazard ratio, 3.15). CMV antigenemia seems to be a good predictor of CMV disease in patients with AIDS.

AIDS-Related Opportunistic Infections↗

Evaluation of the SENIC risk index in a Spanish university hospital.

OBJECTIVE: To assess the performance of the Study of the Efficacy of Nosocomial Infection Control (SENIC) risk index for the evaluation of the risk of surgical-site infection (SSI) in a country other than the United States, having a different health system. SETTING: 350-bed university hospital in Spain belonging to the National Health System (Insalud). DESIGN: Observational cohort study of 1,019 patients who underwent consecutive surgery from January to December 1992. Surgical-infection risk factors assessed by the traditional wound-classification system (clean, clean-contaminated, contaminated, and dirty-infected wound) and by the SENIC risk index (length of intervention more than 2 hours, more than three discharge diagnoses, abdominal surgery, and contaminated or dirty-infected wound) were compared by forward logistic regression. RESULTS: The SENIC risk index showed a greater ability to predict SSI than the traditional wound-classification system. The study carried out in our institution reproduced the estimators provided by the SENIC study in the United States. The SENIC risk index provided a stepwise increase in SSI rates, according to the number of factors present, for every traditional wound-classification group. In the case of clean wounds, the incidence of surgical infection (per 100 interventions) increased (1.5, 2.4, 5.3, and 50; P<.001) for patients having from zero to three risk factors of the SENIC risk index. CONCLUSIONS: This study shows that the SENIC risk index results are reproducible, and the index can be used to compare rates of wound infection across countries with different health systems than the United States.

Abstracting and Indexing↗

Clinical presentation of HIV infection in patients aged 50 years or older.

OBJECTIVES: To describe the clinical presentation of HIV disease in older patients. METHODS: In the period 1989-1996 we reviewed the medical records of 100 patients with human immunodeficiency virus (HIV) infection aged 50 years or older and, 197 controls among HIV-infected patients aged 15-40 years, who attended six institutions in the autonomous community of Valencia (Spain). RESULTS: Older patients were mostly males (86%), men who have sex with men (42%) or unknown (20%) as exposure categories. Older patients had lower CD4 cell counts/mm3 (163+/-136 vs. 450+/-373, P= 0.008), and had AIDS at first evaluation (49% vs. 29%, P = 0.0006) compared with younger patients. For patients presenting with AIDS at HIV infection diagnosis, type and frequency of AIDS indicator diseases did not differ between older and younger patients. CONCLUSION: Studies on clues for early detection of HIV infection in patients aged 50 years or older are urgently needed to improve the health care in this population.

AIDS-Related Opportunistic Infections↗

Genetic alterations and oxidative metabolism in sporadic colorectal tumors from a Spanish community.

Deletions of loci on chromosomes 5q, 17p, 18q, and 22q, together with the incidence of p53 mutations and amplification of the double minute-2 gene were investigated in the sporadic colorectal tumors of 44 patients from a Spanish community. Chromosome deletions were analyzed by means of loss of heterozygosity analysis using a restriction fragment length polymorphism assay. Allelic losses were also detected by polymerase chain reaction (PCR)-single-stranded conformation polymorphism (SSCP) analysis of a polymorphic site in intron 2 of the p53 gene. The percentages of genetic deletions on the screened chromosomes were 39.3% (5q), 58.3% (17p), 40.9% (18q), and 40% (22q). Mutations in p53 exons 2-9 were examined by PCR-SSCP analysis and direct sequencing of the mutated region. Twenty of 44 tumor samples (45.45%) showed mutations at various exons except for exons 2, 3, and 9, the most frequent changes being G-->T transversion and C-->T transition. Because oxygen-free radicals play a role in the carcinogenesis process, we evaluated the oxidative status of the colorectal tumors. Antioxidant activities, lipid peroxidation, and DNA-damaged product concentrations in colon tumors and normal mucosa were compared. In tumor tissues, superoxide dismutase and catalase decreased fourfold and twofold, respectively, whereas glutathione peroxidase and reduced glutathione increased threefold. Malondialdehyde and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels were twofold higher in colorectal tumors than in normal mucosa. Seven of 10 DNA tumor samples (70%) showing higher values of 8-OHdG also had genetic alterations at different chromosomal loci. In these samples, the p53 gene was deleted or mutated in 71.4% of cases. We concluded that the observed changes in the oxidative metabolism of the tumor cells and the consecutive increase in DNA damage may potentiate the genomic instability of different chromosomal regions, leading to further cell malignancy and tumor expansion.

8-Hydroxy-2'-Deoxyguanosine↗

The role of 8-hydroxy-2'-deoxyguanosine in rifamycin-induced DNA damage.

The effect of rifamycin SV on the formation of 8-hydroxy-2'-deoxyguanosine (8-0HdG) has been investigated in vitro and in vivo. Oxidative modification of 2'-deoxyguanosine has been measured as an indication of DNA damage using high-performance liquid chromatography with electrochemical detection. Rifamycin SV in the presence of copper(II) ions induces the formation of 8-0HdG in calf thymus DNA. The effect is enhanced by increasing the antibiotic concentration and inhibited by catalase and hydroxyl radical (.0H) scavengers, such as thiourea and ethanol, in a rifamycin SV concentration-dependent manner. The reduced glutathione (GSH) inhibits DNA damage, and this effect is proportional to the final concentration of the tripeptide in the incubation medium. A significant increase in the formation of 8-0HdG and of malondialdehyde (MDA) in rat liver DNA was observed only in GSH-depleted animals after 5 days of rifamycin SV treatment. These results support the involvement of hydrogen peroxide (H2(0)2) and .0H in the mechanism of the oxidative modification of DNA achieved by rifamycin SV. The role of other reactive species and the antioxidant properties of GSH against oxidative damage is also discussed.

Animals↗

Long-term efficacy of a program to control methicillin-resistant Staphylococcus aureus.

The long-term efficacy of a program to control methicillin-resistant Staphylococcus aureus (MRSA) was evaluated in a 350-bed university hospital. Three periods were monitored: pre-epidemic (January 1989-November 1989), outbreak (December 1989-June 1990) and control program (July 1990-December 1992) periods. Control measures included cohort isolation, patient care measures and therapy (oral cotrimoxazole plus fusidic acid ointment) of MRSA carriage in patients, roommates and personnel. A total of 117 MRSA-infected patients were detected. For each period respectively, MRSA incidence (number of cases per 1,000 patient-days) was 3.2, 8.2 and 2.0 in the intensive care unit (ICU) and 0.08, 0.23 and 0.26 in the general wards. During the outbreak there was a 2.7-fold overall increase of baseline MRSA incidence (p < 0.02). The crude mortality was 68% and the attributable mortality was estimated to be 50%. The program was estimated to have prevented 76% (CI95 28-91, p < 0.0001) of expected MRSA cases and 85% (CI95 62-94, p < 0.0001) of expected fatalities due to MRSA in the ICU, but it had no significant effect in the general wards. The program did not control vancomycin consumption.

Carrier State↗

Low-dose oral chloroquine in patients with porphyria cutanea tarda and low-moderate iron overload.

OBJECTIVE: to assess the efficacy, tolerance and determinants for relapse in patients with porphyria cutanea tarda treated with low-dose oral chloroquine. DESIGN: open trial with a median follow-up of 3 years. SETTING: outpatient referral unit of a university hospital. PATIENTS: 53 patients with low-moderate iron overload or intolerance to phlebotomies. INTERVENTION: 250 mg twice weekly oral chloroquine diphosphate until remission or failure to respond. MEASUREMENTS: porphyrin excretion, biochemical changes and development of side effects. RESULTS: after administration of a median dose of 23.5 g of chloroquine (limits 12.6-56 g) during a median time of 8 months (limits: 1-26 months), 50 patients (94%) reached a metabolic remission (urinary uroporphyrin excretion < 100 micrograms/l). In 14 of these patients (28%), porphyrin excretion further decreased after finishing chloroquine therapy. Metabolic remission persisted during 24 months (limits 6-97 months). Side-effects (severe pruritus) appeared only in one patient. Twenty-two patients relapsed, the relapses being associated with greater basal values of serum AST, ALT, gammaglobulin, urinary uroporphyrin and to the time needed to achieve remission. One year and three years after finishing therapy the probabilities of relapse were 12% (95% C.I.: 5-27%) and 49% (95% C.I.: 34-67%), respectively. Time to achieve remission was the only independent predictor of relapse (hazard ratio: 1.2, 95% C.I.: 1.05-1.21, P < 0.01). CONCLUSION: low-dose oral chloroquine is a safe therapy that promotes a high proportion of remission and sustained control of porphyria cutanea tarda associated with low-moderate iron overload.

Administration, Oral↗

Protective effect of exogenous coenzyme Q against damage by adriamycin in perfused rat liver.

We have investigated the effect of rat liver perfusion with adriamycin on mitochondrial activities. Although the perfusion treatment per se induces some decline of respiratory activities, adriamycin strongly potentiates this effect; moreover the coenzyme Q9 content of the mitochondrial membrane is significantly lowered by the antibiotic. Coaddition of coenzyme Q10 in the perfusate significantly protects the mitochondria, not only from loss of respiratory activities but also of the endogenous CoQ9 content. Exogenous CoQ10 fails to enhance respiratory activities in control rats, not treated with adriamycin, even though CoQ concentration has been proven not to be kinetically saturating in the respiratory chain under physiological conditions. Thus, the beneficial effect of CoQ10 in the perfusate does not appear to be the result of its role in the respiratory chain but is a consequence of its antioxidant action.

Animals↗

The function of coenzyme Q in mitochondria.

We have accumulated evidence that coenzyme Q (CoQ) concentration in the mitochondrial membrane is not saturating for NADH oxidation but is saturating for succinate and glycerol-3-phosphate oxidation. As a result of its kinetic properties CoQ concentration changes must yield changes in respiration rates. This provides a rationale for the reported therapeutic effects of CoQ under conditions when its concentration is decreased, as has been reported in tissues from aged rats; we have failed, however, to detect any specific CoQ decrease in mitochondria from several tissues of aged rats. We can, however, predict from the kinetic bases that CoQ would ameliorate respiration rate also under conditions in which a defect is present in regions not involving the quinone. CoQ incorporation in perfused liver is attempted in order to find experimental systems for investigating its protecting effect. Liposomal CoQ10 perfused in rat livers (where CoQ9 is the main homolog) is incorporated mainly in lysosomes, and its increase in the crude mitochondrial fraction could be mainly ascribed to residual lysosomal contamination. Nevertheless, perfusion with exogenous CoQ10 maintains higher levels of endogenous CoQ9, and higher glutamate oxidation than in controls. In the same system, an oxidative stress by doxorubicin induces mitochondrial changes, including a decrease in endogenous CoQ9 and in respiratory activities. These changes are prevented by concomitant perfusion of liposomal CoQ10.

Aging↗

Progestin challenge test in postmenopausal patients.

OBJECTIVES: The purpose of this study is to analyze the characteristics of patients identified with the progestin test. METHODS: We administered the progestin challenge test to 157 postmenopausal women and compared the characteristics of the patients who bled, with those who did not. RESULTS: Bleeding occurred in 14.01% of cases and we found that the number of patients who bled were significantly and independently more overweight, had higher levels of plasma estradiol, had a clear presence of superficial cells in the vaginal epithelium and had been menopausal for fewer years than those who did not bleed. CONCLUSIONS: We concluded that the test identifies women at risk from hormone-related endometrial cancer.

Endometrial Neoplasms↗

Erythrocyte ion fluxes in essential hypertensive patients with left ventricular hypertrophy.

BACKGROUND: Left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular morbidity and mortality in essential hypertension (EH). Several hemodynamic and nonhemodynamic factors have been involved in the development of LVH in hypertension, including abnormalities in cellular ion mobilization. METHODS AND RESULTS: We measured different ion transport systems in erythrocytes from 50 patients with EH classified as having or not having LVH measured by M-mode echocardiography. Thirty-two EH patients (64%) exhibited criteria of LVH, and 18 (36%) did not. When the two groups were compared, patients with LVH were older (44.7 +/- 7.4 versus 37.6 +/- 9.2 years; P < .01) and exhibited higher rates of erythrocyte Na(+)-H+ exchange (9.8 +/- 4.1 versus 7.1 +/- 2.6 mmol.[L.cells.h]-1; P < .05) and higher intraerythrocyte Na+ content (8.5 +/- 1.3 versus 7.5 +/- 0.8 mmol/L per cell; P < .01). Systolic and diastolic blood pressure values, as well as biochemical, hormonal, and other erythrocyte ion transport systems studied did not differ between EH with or without LVH. The results of a multiple linear regression analysis using left ventricular mass index (LVMI) as the dependent variable showed that Na(+)-H+ exchange and the maximal rate of the Na(+)-K(+)-Cl- cotransport were the only two independently significant parameters associated with an increased LVMI. CONCLUSIONS: The increased rate of the erythrocyte Na(+)-H+ exchange and the decreased maximal rate of the Na(+)-K(+)-Cl- cotransport system are both associated with the presence of LVH in EH patients. These abnormalities of ion transport pathways tend to increase the intracellular Na+ content and may be involved in the pathogenesis of LVH in EH.

Adult↗

The role of glutathione in protection against DNA damage induced by rifamycin SV and copper(II) ions.

Incubation of calf thymus DNA in the presence of rifamycin SV induces a decrease in the absorbance of DNA at 260 nm. The effect, was found to be proportional to the antibiotic concentration and enhanced by copper(II) ions. In the presence of rifamycin SV and copper(II), a significant increase in thiobarbituric acid-reactive (TBA-reactive) material is also observed. This effect is inhibited to different degrees by the following antioxidants: catalase 77%; thiourea 72%; glutathione (GSH) 62%; ethanol 52%; and DMSO 34%, suggesting that both hydrogen peroxide (H2O2) and hydroxyl radicals (OH.) are involved in DNA damage. Rifamycin SV-copper(II) mixtures were also found to induce the production of peroxidation material from deoxyribose and, in this case, glutathione and ethanol were the most effective antioxidant substrates with inhibition rates of 91% and 88% respectively. Electrophoretic studies show that calf thymus DNA becomes damaged after 20 min. incubation in the presence of both agents together and that the damaged fragments run with migration rates similar to those obtained by the metal chelating agent 1,10-phenanthroline. Normal DNA electrophoretic pattern was found to be preserved by catalase, and GSH at physiological concentrations and by thiourea. No protection is observed in the presence of ethanol or DMSO. The results obtained indicate the involvement of different reactive species in the degradation process of DNA due to rifamycin SV-copper(II) complex and emphasize the role of reduced glutathione as an oxygen free radical scavenger.

Copper↗

Effect of metal ion catalyzed oxidation of rifamycin SV on cell viability and metabolic performance of isolated rat hepatocytes.

The effect of rifamycin SV on metabolic performance and cell viability was studied using isolated hepatocytes from fed, starved and glutathione (GSH) depleted rats. The relationships between GSH depletion, nutritional status of the cells, glucose metabolism, lactate dehydrogenase (LDH) leakage and malondialdehyde (MDA) production in the presence of rifamycin SV and transition metal ions was investigated. Glucose metabolism was impaired in isolated hepatocytes from both fed and starved animals, the effect is dependent on the rifamycin SV concentration and is enhanced by copper (II). Oxygen consumption by isolated hepatocytes from starved rats was also increased by copper (II) and a partial inhibition due to catalase was observed. Cellular GSH levels which decrease with increasing the rifamycin SV concentration were almost depleted in the presence of copper (II). A correlation between GSH depletion and LDH leakage was observed in fed and starved cells. Catalase induced a slight inhibition of the impairment of gluconeogenesis, GSH depletion and LDH leakage in starved hepatocytes incubated with rifamycin SV, iron (II) and copper (II) salts. Lipid peroxidation measured as MDA production by isolated hepatocytes was also augmented by rifamycin SV and copper (II), especially in hepatic cells isolated from starved and GSH depleted rats. Higher cytotoxicity was observed in isolated hepatocytes from fasted animals when compared with fed or GSH depleted animals. It seems likely that in addition to GSH level, there are other factors which may have an influence on the susceptibility of hepatic cells towards xenobiotic induced cytotoxicity.

Animals↗

[The usefulness and limitations of adenosine deaminase in the diagnosis of tubercular pleurisy. A meta-analytical study].

To assess the yield of adenosine deaminase (ADA) measurement in the diagnosis of tuberculous pleuritis and to afford parameters applicable to different populations and risk groups, a meta-analysis was performed in this study. National and anglo-saxon studies included in the Index Medicus from 1980 to march of 1990 were reviewed. The estimated incidence of tuberculous pleuritis in our medium was about 0.18 (confidence intervals for 95%-95% CI: 15-0.21). The diagnostic yield of ADA was as follows: sensitivity of 0.99 (95% CI: 0.98-0.99) and specificity of 0.93 (95% CI: 0.91-0.94). The quotients of probability (parameters that measure the predictive values of the tests at any given prevalence) were 14.31 and 0.004 for the positive and negative tests, respectively. In or medium the positive and negative predictive values were 0.74 (95% CI: 0.68-0.81) and 0.99 (95% CI: 0.98-0.99), respectively. An ADA value below the discriminative level nearly rules out the existence of tuberculous pleuritis, whereas at the contrary, and ADA value above the discriminative point offers a limited information about the etiology of the pleural effusion.

Adenosine Deaminase↗