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Biomedical subjects

B Pérez

Publications and source records attributed to B Pérez.

At least 19 recordsLinked to original sources
PubMed2006

First Spanish series of intestinal transplantation in adult recipients.

BACKGROUND: short-bowel transplantation has experienced a substantial growth worldwide following improved results from the late 1990's on, and its coverage by Medicare. According to the International Registry (1985-2005), a total of 1,292 intestinal transplants for 1,210 patients in 65 hospitals across 20 countries have been carried out thus far. OBJECTIVE: to know short-term (6 months) results regarding patient and graft survival from the first Spanish series of intestinal transplants in adult recipients. MATERIAL AND METHODS: we present our experience in the assessment of 20 potential candidates to short-bowel transplantation between June 2004 and October 2005. Of these, 10 patients were rejected and 4 were transplanted, which makes up the sample of our study. RESULTS: to this date 5 transplants have been carried out in 4 patients (2 retransplants, 2 desmoid tumors, 1 short bowel syndrome after excision as a result of mesenteric ischemia). Upon study completion and after a mean follow-up of 180 days (range 90-190 days) all recipients are alive, and all grafts but one (75%) are fully operational, with complete digestive autonomy. All patients received induction with alemtuzumab except one, who received thymoglobulin; in all induction was initiated with no steroids. CONCLUSIONS: intestinal transplantation represents a therapeutic option that is applicable in our setting and valid for recipients with an indication who have no other feasible alternative to keep their intestinal failure under control.

Adult↗
PubMed2005

Sensitive stripping voltammetry of heavy metals by using a composite sensor based on a built-in bismuth precursor.

A new graphite-epoxy composite electrode (GECE) containing Bi(NO(3))(3) as a built-in bismuth precursor for simultaneous and individual anodic stripping analysis of heavy trace metals like lead and cadmium is reported. The developed Bi(NO(3))(3)-GECE is compatible with bismuth film electrodes reported previously including the composite electrodes (Bi-GECE) recently reported by our group. Bi(NO(3))(3)-GECE displays the ability for the detection of both individual and simultaneous determination of heavy trace metals and exhibits well defined, reproducible and sharp stripping signals. The sensitive response is combined with the minimal toxicity of Bi(NO(3))(3). This novel sensor would be an appropriate alternative tool to sensors using bismuth in solution during their utilization in environmental quality monitoring as well as other applications.

Bismuth↗
PubMed2005

Incidence and risk factors of development of lung tumors after liver transplantation.

INTRODUCTION: Lung tumors have been related to tobacco and alcohol. The incidence increases after orthotopic liver transplantation (OLT) especially when it is performed because of alcoholic cirrhosis. PATIENTS AND METHODS: We analyzed the incidence and risk factors for de novo lung tumors among 701 patients who underwent OLT between April 1986 and July 2004, after exclusion of pediatric recipients and adults who died within 2 months after OLT. RESULTS: The incidence of de novo lung tumors was 15 patients (2.1%), including 12 (4.3%) who underwent OLT for alcoholic cirrhosis and 3 (0.7%) for nonalcoholic diseases. There were 14 men and 1 woman of mean age at OLT of 50.8 +/- 9.6 years. Mean time from OLT to lung tumor was 83 +/- 43 months (range, 10-184 months). Thirteen patients (86.6%) were heavy smokers before OLT and 8 (61.5%) continued after OLT; 12 patients (80%) were heavy drinkers before OLT. Ten patients were immunosuppressed with CyA and 5 with tacrolimus. Acute rejection episodes before tumor diagnosis occurred in 6 patients (40%). Two patients underwent thoracotomy, but only one was resected. The remaining 13 patients were unresectable because of locally advanced tumor or metastatic disease. Two unresectable patients received palliative chemotherapy. All patients died with a mean survival from tumor diagnosis, of 5.3 months (range, 3 days to 33 months). CONCLUSION: A significantly higher incidence of lung tumors was observed among patients who underwent OLT for alcoholic cirrhosis, usually diagnosed in advanced stages of poor prognosis and low survival.

Adult↗
PubMed2005

Comparative analysis of the results of orthotopic liver transplantation in patients with and without portal vein thrombosis.

INTRODUCTION: Portal vein thrombosis (PVT), which had been considered an absolute contraindication to orthotopic liver transplantation (OLT), is currently considered a risk factor that increases morbi-mortality. The objective of this study was to compare OLT outcomes in patients with vs without PVT. MATERIALS AND METHODS: Between April 1986 and December 2003, a sample of 83 patients with PVT was compared with another sample of 83 patients without PVT among 962 OLT performed in our department. RESULTS: Both groups were homogeneous in terms of epidemiological variables, surgical technique, immunosuppression, and donor-related variables. There were no differences with respect to graft function during the first week following surgery. Surgical time and anhepatic phase duration was longer in the PVT group, albeit the differences were not significant. PVT patients also required more transfusions; a strong statistical association was observed with respect to blood (P = .12) and plasma (P = .11) transfusions and statistically significant differences regarding platelet transfusions (P = .02). Time on mechanical ventilation and the length of stay in the ICU were longer but not significant among PVT patients. The only statistically significant difference was the incidence of portal rethrombosis (P = .02). With respect to mean and global patient and graft actuarial survivals after 1, 3, 5, and 10 years, we have observed no significant intergroup differences, although both patient (P = .48; NS) and graft (P = .96, NS) survivals were lower among PVT cases. CONCLUSIONS: PVT should not only cease to be considered a contraindication for OLT, but there were no significant differences between the outcomes despite this finding.

Adolescent↗
PubMed2005

Modulation of hepatocyte growth factor plasma levels in relation to the dose of exogenous heparin administered: an experimental study in rats.

INTRODUCTION: Partial liver transplantation has been consolidated to be a valid treatment option. We sought to understand the factors that modulate and may be harnessed to accelerate hepatocyte regeneration. We sought to determine the impact of heparin on m-hepatocyte growth factor (HGF) plasma concentrations. MATERIALS AND METHODS: Sixteen rats were assigned to four groups of four animals each: group A, without heparin; group B, 600 IU/kg; group C, 1000 IU/kg, group D, 1400 IU/kg. Blood samples (0.5 mL) were obtained from each rat at baseline and at 30, 60, 120, and 240 minutes. After the samples were centrifuged to separate supernates from the cell phase they were stored at -20 degrees C in the m-HGF reagent and subsequently tested using enzyme-linked immunosorbent assay. Results were analyzed using SPSS 11.5 statistical software. RESULTS: Among the 16 rats, one died at 110 minutes, just prior to the last extraction. The remaining rats were sacrificed. Mean weight was: 466 +/- 64.24 g with no intergroup differences (P = .149). The comparative results (using Student t test) were: baseline A(1-4) versus A(1-4) 30 minutes: P < .05; baseline A(1-4) versus A(1-4) 60 minutes: P < .05; baseline A(1-4) versus A(1-4) 120 minutes: P = .10 (NS); baseline A(1-4) versus A(1-4) 240 minutes: P = .15 (NS). No significant differences were found among group B: baseline C(1-4) versus C(1-4) 30 minutes and 60 minutes: NS; baseline C(1-4) versus C(1-4) 120 minutes: P < .001; baseline C(1-4) versus C(1-4) 240 minutes: P < .10 (NS). Finally, the results in group D were: baseline D(1-4) versus D(1-4) 30 minutes: NS; baseline D(1-4) versus D(1-4) 60 minutes and 120 minutes: P < .05; baseline D(1-4) versus D(1-4) 240 minutes: P < .0005. When we compared group A to C and D, we detected differences (albeit not when compared to B) with P values = .01. Peak values were obtained at 120 and 240 minutes (225.21 pg/mL and 221.78 pg/mL) among groups C and D. CONCLUSION: Heparin has a positive effect to increase serum HGF concentrations among rats. The effect was dependent on the administered dose and the time elapsed.

Animals↗
PubMed2005

PK and PK/PD of doxycycline in drinking water after therapeutic use in pigs.

A commercial doxycycline formulation was administered in drinking water to 12 pigs at the recommended dose of 10 mg/kg daily for 5 days. The mean plasma concentration at steady-state was 1.37 +/- 1.21 microg/mL, which was reached at 68 +/- 27.2 h postadministration. Absorption and elimination half-life values were 7.20 +/- 2.42 and 7.01 +/- 2.10 h, respectively. Most plasma concentrations during dosing were higher than the minimum inhibitory concentrations (MICs) described for the main porcine bacterial pathogens of the respiratory tract (Pasteurella multocida, Actinobacillus pleuropneumoniae, Bordetella bronchiseptica and Mycoplasma hyopneumoniae). It is concluded that when pigs were treated with doxycycline in drinking water at the recommended rate, therapeutically effective concentrations were achieved throughout the treatment period, supporting the clinical use of this tetracycline in the control of respiratory infections. However, inter-animal differences were marked.

Actinobacillus pleuropneumoniae↗
PubMed2004

Prenatal diagnosis of propionic acidemia.

In this report we summarize our experience in prenatal diagnosis of propionic acidemia (PA) since 1987. Overall, we have investigated 25 pregnancies at risk from 19 unrelated families. Until genetic structure of the genes involved in PA was elucidated, prenatal diagnosis has been successfully performed by means of metabolite quantitation and/or enzymatic assays in foetal issue. Today, direct propionyl-CoA carboxylase activity assay in combination with molecular analysis in chorion villi can be regarded as a fast and reliable method of choice for prenatal diagnosis of this organic acidemia.

Amniotic Fluid↗
PubMed2003

Functional analysis of PCCB mutations causing propionic acidemia based on expression studies in deficient human skin fibroblasts.

Propionic acidemia (PA) is a recessive disorder caused by a deficiency of propionyl-CoA carboxylase (PCC), a dodecameric enzyme composed of two different proteins alpha-PCC and beta-PCC, nuclear encoded by the PCCA and PCCB genes, respectively. Mutations in either gene cause PA and to date, up to 47 different allelic variations in the PCCB gene have been identified in different populations. In this work, we describe the expression studies of 18 PCCB sequence changes in order to elucidate their functional consequences. We have used a PCCB-deficient transformed fibroblast cell line to target the wild-type and mutant proteins to their physiological situation, analysing the effect of the mutations on PCC activity and protein stability. Of the 18 mutant proteins tested for activity, those carrying the L17M and A497V substitutions showed an activity similar to the wild-type one, which proves that these changes do not have any effect on protein activity. The other 16 mutant proteins exhibited two different functional behaviours, 3 retained substantial activity (K218R, R410W and N536D), and the remaining 13 proteins showed null or very low activity. Western blot analysis demonstrated instability only for the L519P, R512C and G112D mutant proteins. We have proved the pathogenicity of R67S, R165Q and G112D mutation in PCCB gene, expressed for the first time in this work. The information derived from the expression analysis is discussed in the phenotype and genotype context in order to improve the knowledge of this complex disease.

Amino Acid Metabolism, Inborn Errors↗
PubMed2003

[Correlation between otoacoustic emissions and BAEP. The importance of their combined use].

Auditory Brainstem Response (ABR) of 50 newborn with negative transient evoked acoustic emissions (OEAT) was performed. 54% of them had no family history of sensorineural hearing loss (SHNL) and no risk factors were found. In 70% of cases ABR recording was negative. Follow up did show that 60% of them had normal recordings of hearing and in a 40% different stages of hearing loss were seen. To establish a definitive diagnosis a 1 to 9 month period is necessary.

Deafness↗
PubMed2003

Changes in the incidence and severity of recurrent hepatitis C after liver transplantation over 1990-1999.

BACKGROUND/AIM: Changes in immunosuppression and other factors may have changed the severity of recurrent hepatitis C during recent years. This study sought to establish the changes in incidence and severity of recurrent hepatitis C, and its association with the changes in acute rejection and induction immunosuppressive therapy between 1990 and 1999. PATIENTS AND METHODS: Among 213 liver transplants in HCV-infected recipients, 129 grafts were selected for this study: all grafts with severe recurrent hepatitis C (fibrosis 3-4 in Scheuer's score or fibrosing cholestatic hepatitis), and those grafts without severe recurrence with at least 2 years of follow up. Grafts were divided in 5 groups depending on the year of transplantation to compare recurrent hepatitis C-related variables, AR incidence and induction immunosuppression. RESULTS: Hepatitis-free survival decreased in recent years (p=0.015). The incidence of fibrosing cholestatic hepatitis was higher among 1996-1997 and the 1998-1999 periods (p=0.019). Survival free of severe hepatitis at 1 year follow up was 95% in 1990-1991 and 80% in 1998-1999; however, in the long-term the survival was similar between groups (p=0.933). HCV-related graft survival at 5 years was 93.5% in the 1990-95 period and 82.5% in 1996-99 (p=0.068). Neither AR nor any regimen of induction immunosuppression was associated with changes in the occurrence of recurrent hepatitis C related survival. CONCLUSIONS: Severity of recurrent hepatitis C and HCV-related graft loss after liver transplantation were higher in the second half of the 1990s; however, there was no association with AR or induction immunosuppression.

Disease-Free Survival↗
PubMed2003

Propionic acidemia: identification of twenty-four novel mutations in Europe and North America.

Propionic acidemia is an inherited metabolic disease caused by the deficiency of the mitochondrial protein propionyl-CoA carboxylase (PCC), one of the four biotin-dependent enzymes. PCC is a multimeric protein composed of two different alpha- and beta-PCC subunits, nuclearly encoded by the PCCA and PCCB genes, respectively. Mutations in either gene cause the clinically heterogeneous disease propionic acidemia. In this work we describe the mutational analysis of PCCA and PCCB deficient patients from different European countries (Spain, Italy, Belgium, Croatia, and Austria) and from America (mainly USA). We report 24 novel PA mutations, nine affecting the PCCA gene and 15 affecting the PCCB gene. They include six missense mutations, one nonsense mutation, one point exonic mutation affecting splicing, seven splicing mutations affecting splice sequences, and nine short insertions or deletions, only two in-frame. We have found a highly heterogenous spectrum of PCCA mutations, most of the PCCA deficient patients are homozygous carrying a unique genotype. The PCCA mutational spectrum includes a high proportion of short insertions or deletions affecting one nucleotide. In the PCCA mutant alleles analyzed we have also found one single nucleotide change, a novel nonsynonymous SNP. On the other hand, the PCCB deficient patients carry a more reduced spectrum of mutations, 50% of them are missense. This work represents an extensive update of the mutational study of propionic acidemia providing important information about the worldwide distribution of PA mutations and representing another essential part in the study of the phenotype-genotype correlations for the prediction of the metabolic outcome and for the implementation of treatments tailored to each PA patient.

Alternative Splicing↗
PubMed2003

Functional analysis of MCCA and MCCB mutations causing methylcrotonylglycinuria.

Methylcrotonylglycinuria (MCG; MIM 210200) is an autosomal recessive inherited human disorder caused by the deficiency of 3-methylcrotonyl-CoA carboxylase (MCC, E.C.6.4.1.4), involved in leucine catabolism. This mitochondrial enzyme is one of the four biotin-dependent carboxylases known in humans. MCC is composed of two different types of subunits, alpha and beta, encoded by the nuclear genes MCCA and MCCB, respectively, recently cloned and characterized. Several mutations have been identified, in both genes, the majority are missense mutations along with splicing mutations and small insertions/deletions. We have expressed four missense mutations, two MCCA and two MCCB mapping to highly evolutionarily conserved residues, by transient transfection of SV40-transformed deficient fibroblasts in order to confirm their pathogenic effect. All the missense mutations expressed resulted in null or severely diminished MCC activity providing direct evidence that they are disease-causing ones. The MCCA mutations have been analysed in the context of three-dimensional structural information modelling the changes in the crystallized biotin carboxylase subunit of the Escherichia coli acetyl-CoA carboxylase. The apparent severity of all the MCC mutations contrasts with the variety of the clinical phenotypes suggesting that there are other cellular and metabolic unknown factors that affect the resulting phenotype.

Amino Acid Sequence↗
PubMed2002

Determination of tylosin residues in different animal tissues by high performance liquid chromatography.

A HPLC method to determine and quantify tylosin residues from calves, pigs and poultry is reported. This procedure permitted tylosin to be separated from muscle, liver, kidney and fat after a simple extraction with chloroform or ethyl acetate under basic conditions. The analytical methodology showed a high specificity and sensitivity and an adequate precision and accuracy with a limit of quantification of 50 microg/kg. Eight calves were administered 20 mg/kg/day of tylosin for 5 days and slaughtered at 7 and 14 days post-administration. Results showed that at the 14th day tylosin levels were lower than the MRL in all target tissues.

Animals↗
PubMed2002

Transfection screening for defects in the PCCA and PCCB genes encoding propionyl-CoA carboxylase subunits.

Propionic acidemia can result from mutations in the PCCA or PCCB genes encoding the alpha and beta subunits, respectively, of propionyl-CoA carboxylase. We have developed a method based on complementation of the enzyme defect using a lipid-mediated transient transfection of the normal human PCCA or PCCB cDNA into primary fibroblasts. We demonstrate the reliability of this method for identification of the defective PCC gene in order to unequivocally approach the mutational analysis in the corresponding PCCA and PCCB genes.

Carboxy-Lyases↗
PubMed2002

Disposition kinetics of tylosin administered intravenously and intramuscularly to pigs.

The distribution of tylosin was studied using a crossover design, in six pigs following i.v. and i.m. administration of 10 mgkg(-1) b.w. Plasma samples were analysed by HPLC and UV absorbance detection. After i.v. administration, t(1/2beta) was 271.3 min, V(d) 14.6 Lkg(-1), V(ss) 9.7 Lkg(-1) and CL 26.8 mLmin(-1)kg(-1). After i.m. administration, a C(max) of 1 microgmL(-1) was reached at 90 min. Mean absorption time was 1988.7 min and bioavailability was 95%.

Animals↗
PubMed2002

Tylosin depletion from edible pig tissues.

The depletion of tylosin from edible pig tissues was studied following 5 days of intramuscular (i.m.) administration of 10 mg/kg of tylosin to 16 crossbreed pigs. Animals were slaughtered at intervals after treatment and samples of muscle, kidney, liver, skin+fat, and injection site were collected and analysed by high-performance liquid chromatography (HPLC). Seven days after the completion of treatment, the concentration of tylosin in kidney, skin+fat, and at the injection site was higher than the European Union maximal residue limit (MRL) of 100 microg/kg. Tylosin residues in all tissues were below the quantification limit (50 microg/kg) at 10 and 14 days post-treatment.

Administration, Oral↗