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Biomedical subjects

J Olivares

Publications and source records attributed to J Olivares.

At least 19 recordsLinked to original sources

[Fever and cavitary infiltrate in a renal transplant recipient].

Aspergillus infection is a rare but devastating complication following organ transplantation with high mortality rate. Aspergillus fumigatus is the most common cause of invasive aspergillosis. This fungus is present in the environment worldwide. Aspergillus infection is mainly acquired by inhalation of spores and several nosocomial infections in transplant recipient have been associated with construction work at hospitals. Risk factors for invasive aspergillosis include administration of steroid boluses, history of cytomegalovirus infection, neutropenia and prolonged antibiotic use after transplantation. Successful treatment depends on three factors: early diagnosis, aggressive antifungal therapy and decrease or removal of immunosuppression. Amphotericin deoxycholate has been the standard treatment for many years but lipid preparations for amphotericin are now used due to their significantly fewer adverse effects. A number of new antifungal drugs are now being developed including new azoles such as voriconazol and echinocandin. Invasive aspergillosis has a high mortality rate more than 95% when cerebral dissemination is demonstrated. We report the case of a 47 years old woman who received a cadaveric renal graft and developed pulmonary aspergillosis with fulminant cerebral dissemination two months later. The diagnosis of pulmonary aspergillosis was by culture isolation obtained from bronchioalveolar lavage. Removal of immunosuppresive agents and liposomal amphotericin B therapy were started shortly after admission. Brain CT scan performed on the 12th day showed cerebral dissemination. The recipient died two days later. Our patient had several risk factors such as the administration of steroid boluses and cytomegalovirus infection. Invasive aspergillosis must be always included in the differential diagnosis of fever and pulmonary disease in the renal transplant recipient.

Amphotericin B↗

Study of the correlation between two methods used to monitor thymoglobulin therapy in renal transplantation.

The aim of this study is to evaluate the correlation between the 2 methods used to monitor thymoglobulin therapy: the total lymphocyte count and the number of T cells. We have performed daily collections of peripherical blood samples from 24 renal grafts, recipients who were receiving thymoglobulin, including 14 cases for induction and 10 for acute rejection. Absolute lymphocyte and T-cell counts were measured in the 298 samples after administration of a dose of 1.25 mg/kg/d. The dose was omitted if the T-cell count had decreased to <10 cells/microL. The theoretical total lymphocyte count considered to omit dose was <100 cells/microL. A total of 137 doses were given according to T-cell count. We performed the comparison in 3 steps. First, we correlated values in the daily samples; second, we examined samples as a whole and third, assessed the percentage of discrepancy between the omission of the daily dose according to each method. There was a poor correlation between the methods according to sets of daily samples or the sets as a whole. The rate of discrepancy was 66%, including 121 of 216 decisions (P<.001). In conclusion, the results of the 2 methods of monitoring thymoglobulin therapy are different, and the total administered dose depends on the method used.

Antilymphocyte Serum↗

[Effect of arterial pressure and age on renal function, The "Care for the Kidney" study].

BACKGROUND: The kidney is one of the principal target organs of hypertension. The mechanism by which hypertension damages the kidney and the relative contribution of high blood pressure to the progression of renal failure remains incompletely defined. The clinical quantification of renal function is usually thought to require determination of plasma clearance of endogenous creatinine (ClCr), an impractical test for epidemiological evaluation. For this reason several formulae have been proposed to estimate the ClCr from the serum creatinine concentration, such as sex, age, and body weight. The most often used formula is the one proposed by Crockroft and Gault in 1976. OBJECTIVE: To determine the prevalence of loss of renal function and the influence of hypertension and age on this loss in hypertensive and normotensive patients. PATIENTS AND METHOD: An observational, cross-sectional comparative study was carried out. 3,420 patients (1,171 normotensive and 2,249 hypertensive) were studied. Average age was 70 years (19.4% of patients < 65 years; 23.3% > 75 years). 98.1 of hypertensive patients were treated with drugs, 26.7% of them with more than one drug. 27.9% of treated patients achieved blood pressure control (< 140-90 mm Hg). The level of renal function was estimated by means of ClCr using the Crockroft and Gault formula. RESULTS: 3.9% of normotensive and 12.2% of hypertensive patients had serum creatinine values > 1.3 mg/dl, but 28.6% of normotensive and 40.4% of hypertensive had ClCr < 60 ml/min. The patients over 75 years had ClCr mean values < 60 ml/min. There was correlation between ClCr and age, but there was no correlation between ClCr and blood pressure values. CONCLUSIONS: The estimated ClCr decrease with age and there existed correlation between both variables. The ClCr is lower in hypertensive than in normotensive patients. Hypertension and age influence loss of renal function, but age is a determining factor. The estimated ClCr was a more sensible method of evaluating the loss of renal function than the serum creatinine values. The use of Crockroft and Gault formula can be useful for making diagnostic and therapeutic decisions in primary care.

Aged↗

[Mycophenolate mofetil in lupus nephritis].

The treatment of severe lupus nephritis is based on the combination of steroids and cytotoxic drugs. Intravenous cyclophosphamide administered in "pulses" is effective in the induction of remission but other therapeutic alternatives are sought in refractory cases or severely relapsing patients. Mycophenolate mofetil, used in renal transplantation, also can be useful in severe lupus nephritis. We describe the evolution of 6 patients (5 women and 1 man; age 17-45 years) with severe lupus nephropathy who after achieving remission with intravenous cyclophosphamide and steroids (5 cases) or cyclosporin A (1 case) showed relapse of proteinuria and were treated with mycophenolate mofetil (dose 1000-2000 mg/day). Two patients have completed 24 months, 1 patient two cycles of 12 months, 2 patients 18 months and 1 patient 6 months. After this treatment, all patients have achieved remission (3 partial and 3 complete). There was no treatment failure and no one patient discontinued medication; however 1 case relapsed. There were no changes in leucocytes, haemoglobin, serum creatinine and serum albumin. ANA and alpha DNA antibodies decreased. Proteinuria (measured as protein/creatinine urine ratio: initial 3 and final 0.3) and dose of steroids (initial: 17.5 mg/d and final 5 mg/d) decreased significantly (p < 0.05 Wilcoxon t-test). The most common side effects were nausea and abdominal discomfort that improved without discontinuation of treatment. We conclude that mycophenolate mofetil is effective and a safe drug in severe relapsing lupus nephritis.

Adolescent↗

[Changing profiles of proteinuria in renal transplantation. Predictive factors for its appearance].

Proteinuria is a risks factor that accelerates the progression of renal insufficiency by several mechanisms. In the renal transplant proteinuria is a predictor of progressive renal insufficiency and it is associated with poor patient and graft survival. We have performed a longitudinal observational case-control study to defect and quantify proteinuria in a group of 100 cadaveric renal transplant recipients and to evaluate the influence of several factors on its appearance. We have considered the variables age and sex of the donor and recipient, number of HLA-DR, A and B mismatches, cold ischemia time, basal renal disease, initial immunosuppression, immediate versus delayed graft function and acute rejection. Three patients who did with a functioning graft were excluded from the analysis of the data. All variables were analysed in a regression model of multivariate analysis. Proteinuria in the moths 1, 3, 6, 9 and 12 was: 0.38 +/- 0.27 g/day, 0.38 +/- 0.32 g/day, 0.44 +/- 0.99 g/day, 0.42 +/- 0.58 g/day and 0.37 +/- 0.54 g/day, respectively. We analysed the profile of the proteinuria in each patient individually. Fifty three patients (54.6%) did not develop proteinuria, 12 patients (12.4%) had transient initial proteinuria, 23 patients (23.7%) had persistent proteinuria and 9 patients (9.3%) had progressive proteinuria. The renal function differed between groups. Higher creatinine levels were found in the patients with persistent proteinuria and those with progressive proteinuria. We analysed the patients according to several variables. The age of the donor was higher in the group of patients with persistent proteinuria and the incidence of acute rejection was higher in the group of patients who developed progressive proteinuria, with differences statistically significant. There was no difference in the univariate analysis in the other variables considered. The multivariate analysis confirms that the age of the donor and the basal glomerular disease predict persistent proteinuria and acute rejection predicts progressive proteinuria. According to our study, proteinuria is frequent in the renal transplant recipient with different evolutionary profiles. Two types are associated with bad renal function and have different predictive factors. We encourage the use of drugs which reduce proteinuria.

Adult↗

[Diffuse lymphoproliferative disease after renal transplantation and its relation with Epstein-Barr virus. Experience at one center].

Post-transplant lymphoproliferative disorders (PTLD) are a group of heterogeneous lymphoid proliferations in chronic immunosuppressed recipients which appear to be related to Epstein Barr Virus (EBV). Receptor EBV seronegativity, use of antilymphocyte antibodies and CMV disease have been identified as risk factors that may tigger development of PTLD. We have studied the incidence of PTLD and its relationship with EBV in 588 adult renal transplant recipients who were transplanted in our hospital from 1988 to 2001. We have also evaluated the diagnostic and therapeutic methods used, the risk factors and outcome of the patients who developed PTLD. We identified 8 recipients (4 males and 4 females), range from 18 to 67 years (mean age 45.6 years) with a median time between grafting and PTLD of 4.1 years (0.1-7 years), who developed PTLD (1.3%). Only 1 patient received OKT3 and had CMV disease, two of them (25%) had been treated with hight doses of prednisolone, another was EBV seronegative, but the rest of them (50%) had no risk factors. Two patients were diagnosed at autopsy, the diagnosis of 5 was based on the histology of biopsy and the last one by CT scans of chest-abdomen and cytology. The presence of EBV in the lymphoproliferative cells was assessed in 5 out of the 7 studied patients (71.4%). The outcome of our recipients was poor. Five out of 8 patients died shortly after diagnosis as a direct consecuence of PTLD and another of an infectious complication of the treatment (75%). The 2 patients alive started dialysis and 1 of them died 2 years later of a non-related cause. In conclusion, PTLD is a relatively frequent disease with a poor prognosis in renal transplant patients. It seems to have a close relationship with EBV and can develop in the absence of the classical risk factors.

Adolescent↗

Macrocompartmentation of total creatine in cardiomyocytes revisited.

Distribution of total creatine (free creatine + phosphocreatine) between two subcellular macrocompartments--mitochondrial matrix space and cytoplasm--in heart and skeletal muscle cells was reinvestigated by using a permeabilized cell technique. Isolated cardiomyocytes were treated with saponin (50 microg/ml for 30 min or 600 microg/ml for 1 min) to open the outer cellular membrane and release the metabolites from cytoplasm (cytoplasmic fraction, CF). All mitochondrial population in permeabilized cells remained intact: the outer membrane was impermeable for exogenous cytochrome c, the acceptor control index of respiration exceeded 10, the mitochondrial creatine kinase reaction was fully coupled to the adenine nucleotide translocator. Metabolites were released from mitochondrial fraction (MF) by 2-5% Triton X100. Total cellular pool of free creatine + phosphocreatine (69.6 +/- 2.1 nmoles per mg of protein) was found exclusively in CF and was practically absent in MF. When fibers were prepared from perfused rat hearts, cellular distribution of creatine was not dependent on functional state of the heart and only slightly modified by ischemia. It is concluded that there is no stable pool of creatine or phosphocreatine in the mitochondrial matrix in the intact muscle cells, and the total creatine pool is localized in only one macrocompartment--cytoplasm.

Animals↗

Novel erythropoiesis stimulating protein for treatment of anemia in chronic renal insufficiency.

BACKGROUND: Novel erythropoiesis stimulating protein (NESP) is a glycoprotein with a threefold longer terminal half-life than recombinant human erythropoietin (rHuEPO) in humans. The aim of this study was to determine whether NESP is effective for the treatment of anemia at a reduced dosing frequency relative to rHuEPO in patients with chronic renal failure not yet on dialysis [chronic renal insufficiency (CRI)]. METHODS: This was a multicenter, randomized, open-label study. A total of 166 rHuEPO-naive patients with CRI were randomized in a 3:1 ratio to receive NESP (0.45 microg/kg once weekly) or rHuEPO (50 U/kg twice weekly) administered subcutaneously for up to 24 weeks. Dose adjustments were made as necessary to achieve a hemoglobin response, defined as an increase > or =1.0 g/dL from baseline and a concentration > or = 11.0 g/dL. RESULTS: During the 24-week treatment period, 93% (95% CI, 87 to 97%) of patients receiving NESP and 92% (95% CI, 78 to 98%) of patients receiving rHuEPO achieved a hemoglobin response. The median time to response was seven weeks (range of 3 to 25 weeks) in both groups. After correction of anemia, mean hemoglobin concentrations were maintained within the target range of 11.0 to 13.0 g/dL for the remainder of the 24-week treatment period. The safety profiles of NESP and rHuEPO were similar, and no antibodies were detected to either drug. CONCLUSIONS: These results demonstrate that NESP safely and effectively corrects and maintains hemoglobin concentrations at a reduced dosing frequency relative to rHuEPO in patients with CRI, providing a potential benefit to patients and health care providers.

Aged↗

The disruption of a gene encoding a putative arylesterase impairs pyruvate dehydrogenase complex activity and nitrogen fixation in Sinorhizobium meliloti.

Nitrogen-fixing Sinorhizobium meliloti cells depend upon dicarboxylic acids as carbon and energy sources. The metabolism of these intermediate compounds of the trichloroacetic acid cycle is dependent upon the availability of acetyl-coenzyme A (CoA). In bacteroids, the combined activities of malic enzymes and pyruvate dehydrogenase (PDH) have been proposed to be responsible for the anaplerotic synthesis of acetyl-CoA. We obtained a S. meliloti mutant strain, PD3, in which a Tn5 insertion led to a significant decrease in the overall PDH activity. The genetic characterization of this mutant revealed that the transposon is located at the 3' end of a gene (ada) encoding a putative arylesterase. The mutant PD3 is deficient in nitrogen fixation, which strengthens the physiological importance of PDH activity in the symbiosis of S. meliloti with alfalfa plants.

Acetyl Coenzyme A↗

[Distribution of hepatitis C virus genotypes among the hemodialysis population in the province of Alicante].

UNLABELLED: Hepatitis C virus (HCV) genotypes are irregularly distributed among the different geographic area and groups at risk. OBJECTIVE: To study the different HCV genotypes and subtypes of hemodialyzed patients from Alicante. METHODS: We studied 640 patients on haemodialysis (HD) and we determined the RNA-HCV and the genotypes in the 120 patients with antibodies against HCV (HCV-Ab). We compared the results with the genotypes of 1,370 patients from other groups at risk in the same geographic area. RESULTS: RNA-HCV was not found in the serum in 15% (18/120) of the patients on HD who were HCV-Ab positive. Prevalence of the different genotypes in the 102 patients with positive viral RNA was the following: 1b: 56.8% (58/102), 1a: 19.6% (20/102), 3: 17% (17/102), 2a-2c: 1.9 (2/102), 2b: 0.9% (1/102) 4: 2.9 (3/102), 5: 0.9% (1/102). In conclusion, the genotype 1b was the most frequent in the patients studied in all these areas, and was the same as in the rest of the country. This genotype has been associated with the most severe hepatic disease and poor response to treatment, affecting the prognosis of these patients. The most frequent genotypes in HD in Alicante were 1b, 3 and 1a. HCV genotypes distribution among the HD units was not uniform in the different geographic areas. HCV genotypes distribution in the HD population is similar to other groups at risk from the same geographic area.

Adult↗

Rapid spectrophotometric method for quantitation of cytochrome c release from isolated mitochondria or permeabilized cells revisited.

This paper recalls the earlier work by Keilin, Margoliash and others at the beginning of the 20th century and shows how their results can be used for the rapid solution of new problems of modern science. It describes a rapid and simple spectrophotometric method for quantitative determination of cytochrome c release from isolated mitochondria or permeabilized cells induced by proapoptotic proteins. For this, the Soret (gamma) peak at 414 nm in the spectrum of cytochrome c is used. The results of spectrophotometric assay of cytochrome c release are in accord with those of oxygraphic determination of cytochrome c-dependent respiration of isolated mitochondria and permeabilized cardiomyocytes.

Animals↗

A prospective multicenter comparison of peritonitis in peritoneal dialysis patients aged above and below 65 years. Levante PD Multicenter Group.

Various authors have found peritonitis rates in older peritoneal dialysis (PD) patients to be higher, similar, or even lower when compared to rates in younger populations. We prospectively analyzed all episodes of peritonitis registered in the 381 patients (219 males, 162 females; mean age, 55.5 +/- 17.0 years) who were treated with PD during four years (1993-1996) in our multicenter group. Patients were distributed into two groups. Group A included 138 patients aged 65 years or over (mean age: 72.3 +/- 5.1 years); group B included 243 patients aged below 65 years (mean age: 46.0 +/- 13.6 years). No differences were seen in general PD characteristics. Normalized protein catabolic rate (nPCR) was higher in younger patients (p = 0.001). Patients in group A experienced more peritonitis (135 episodes; 1 episode per 16.7 patient-months) than patients in group B (198 episodes; 1 episode per 21.7 patient-months; p = 0.01). Although no differences were seen in the general characteristics of the peritonitis episodes, gram-negative peritonitis and peritonitis not achieving a cure were more commonly secondary to enteric bacteria in group A (p = 0.03). We conclude that PD patients aged 65 years or over are at higher risk of peritonitis. Also, in this age group, gram-negative peritonitis and peritonitis with any evolution except cure are more likely to be due to enteric bacteria.

Age Factors↗

Profilin in Phaseolus vulgaris is encoded by two genes (only one expressed in root nodules) but multiple isoforms are generated in vivo by phosphorylation on tyrosine residues.

Actin-binding proteins such as profilins participate in the restructuration of the actin cytoskeleton in plant cells. Profilins are ubiquitous actin-, polyproline-, and inositol phospholipid-binding proteins, which in plants are encoded by multigene families. By 2D-PAGE and immunoblotting, we detected as much as five profilin isoforms in crude extracts from nodules of Phaseolus vulgaris. However, by immunoprecipitation and gel electrophoresis of in vitro translation products from nodule RNA, only the most basic isoform of those found in nodule extracts, was detected. Furthermore, a bean profilin cDNA probe hybridised to genomic DNA digested with different restriction enzymes, showed either a single or two bands. These data indicate that profilin in P. vulgaris is encoded by only two genes. In root nodules only one gene is expressed, and a single profilin transcript gives rise to multiple profilin isoforms by post-translational modifications of the protein. By in vivo 32P-labelling and immunoprecipitation with both, antiprofilin and antiphosphotyrosine-specific antibodies, we found that profilin is phosphorylated on tyrosine residues. Since chemical (TLC) and immunological analyses, as well as plant tyrosine phosphatase (AtPTP1) treatments of profilin indicated that tyrosine residues were phosphorylated, we concluded that tyrosine kinases must exist in plants. This finding will focus research on tyrosine kinases/tyrosine phosphatases that could participate in novel regulatory functions/pathways, involving not only this multifunctional cytoskeletal protein, but other plant proteins.

Blotting, Western↗

Characterization of Bradyrhizobium japonicum pcaBDC genes involved in 4-hydroxybenzoate degradation.

The pca structural genes encode enzymes that participate in the conversion of protocatechuate to succinate and acetylcoenzyme A. A 3. 05-kb region of the Bradyrhizobium japonicum strain USDA110 genome has been characterized, which contains the pcaB, pcaD and pcaC genes. The predicted protein sequences of the three genes have extensive homologies with beta-carboxy-cis,cis-muconate cycloisomerase (PcaB), beta-ketodiapate enol-lactone hydrolase (PcaD), and gamma-carboxymuconolactone decarboxylase (PcaC), respectively, from Acinetobacter calcoaceticus and Pseudomonas putida. The DNA sequence revealed that the pca genes are probably arranged in a single transcriptional unit, pcaBDC, similar to that described in P. putida. A pcaB deletion mutant constructed by marker exchange mutagenesis lost the ability to use 4-hydroxybenzoate or protocatechuate as the only carbon source, demonstrating functionality of the characterized genes in catabolism of hydroxyaromatics by B. japonicum. Furthermore, 4-hydroxybenzoate and protocatechuate became toxic for the pcaB mutant, indicating that hydroxyaromatics catabolism serves both nutritional and detoxifying purposes.

Amino Acid Sequence↗