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Biomedical subjects

R Valero

Publications and source records attributed to R Valero.

At least 55 records · Page 3Linked to original sources
PubMed1999

Evaluation of ischemic injury during liver procurement from non-heart-beating donors.

UNLABELLED: The aim of this study was to assess liver viability after different periods of cardiac arrest and the predictive value of two markers of ischemia-reperfusion injury. METHODS: A pig liver transplantation model of non-heart-beating donors was studied. Four donor groups were designed; three groups were submitted to different periods of cardiac arrest (20, 30 and 40 min), and the fourth group served as the control group (without cardiac arrest). In the non-heart-beating donor groups, normothermic recirculation was established 30 min prior to total body cooling. Aminotransferase, alpha-glutathione-S-transferase, and hyaluronic acid determinations as well as liver biopsies, were serially performed. RESULTS: Although hepatocellular function could be preserved after 40 min of cardiac arrest, histological lesions at 5 days were considered irreversible due to the presence of a necrotic biliary tract. An overall significant relationship was found between the time period of cardiac arrest (20, 30 or 40 min) and the levels of hyaluronic acid (p = 0.004) or alpha-glutathione-S-transferase (p = 0.01) obtained during liver procurement and transplantation. CONCLUSIONS: The period of cardiac arrest is the determinant factor of liver viability after liver transplantation from non-heart-beating donors. As early markers of endothelial or hepatocellular damage, hyaluronic acid or alpha-glutathione-S-transferase levels may help to evaluate the ischemic injury of a potential donor.

Alanine Transaminase↗
PubMed1999

Molecular characterisation of partial chromosome 21 aneuploidies by fluorescent PCR.

Although trisomy of chromosome 21 is the most prevalent human genetic disorder, data from partial 21 aneuploidies are very scanty. Eight different partial aneuploidies for chromosome 21 were characterised by fluorescence quantitative PCR. Allelic dosage analysis was performed for each patient using 25 CHLC STRs covering the entire q arm. The length of the corresponding trisomies and monosomies was ascertained for five partial trisomics and three partial monosomics. All trisomic patients carried unbalanced translocations involving chromosome 21, whereas one of the monosomic patients bore a ring chromosome 21 and another showed an interstitial deletion of chromosome 21. The chromosomal breakpoints of two partial trisomy patients could be clearly delimited. However, the other three trisomies involved most of the 21 q arm as three allelic doses were detected for each marker. Although these latter patients do not show all the features of Down syndrome, genotype/phenotype correlations agree with previously reported data. The chromosomal breakpoints observed in two partially monosomic patients helped further to define the region involved in different phenotypic features associated with chromosome 21 monosomy. Telomeric material loss was also detected in a patient bearing a ring 21 chromosome. The parental origin of the aneuploidy was assigned for each case, which allowed us to conclude that two of the monosomic cases originated from de novo chromosomal rearrangements. There was no correlation with parental sex in contrast to trisomic patients originating from meiotic nondisjunction.

Aneuploidy↗
PubMed1998

Hepatic blood flow and oxygen extraction ratio during normothermic recirculation and total body cooling as viability predictors in non-heart-beating donor pigs.

BACKGROUND: Our aim was to evaluate the hepatic blood flows and oxygen metabolism of non-heart-beating donor (NHBD) pigs, with the use of cardiopulmonary bypass (CPB) and normothermic recirculation (NR) before total body cooling, and its relationship with recipient survival. METHODS: Thirty-five pigs were transplanted with an allograft from NHBDs. After warm ischemia (WI) time (20, 30, or 40 min), CPB and NR were run for 30 min. After this period, the animals were cooled to 15 degrees C. In the control group (20 min of WI), the period of NR was excluded. Liver procurement was then performed. RESULTS: Survival rate was 100% in the 20WI, 70% in the 30WI, and 50% in the 40WI. Control group survival rate was 0%. Hepatic artery blood flow and portal blood flow recovered during NR. Pump blood flow during CPB increased rapidly during NR and was significantly higher in the 20WI. When donors of the livers transplanted in "surviving pigs" (DSP) were compared with donors of the livers transplanted in "nonsurviving pigs" (DNSP), hepatic artery blood flow, portal blood flow, and pump blood flow were higher in the DSP. Hepatic oxygen extraction ratio increased in the three groups with respect to baseline values. Hepatic oxygen extraction ratio was lower in the 20WI than in the other groups and was lower in the DSP than in the DNSP. CONCLUSIONS: The use of a NR period before total body cooling improves survival of liver transplantation in NHBDs. Portal blood flow and pump blood flow measurements can predict the viability of the grafts.

Animals↗
PubMed1998

[Outcome of patients who underwent surgical repair of aneurysm after subarachnoid hemorrhage].

BACKGROUND: Follow-up study of patients with surgical repair of aneurysmal subarachnoidal hemorrhage (SAH), looking for clinical outcome predictors. PATIENTS AND METHODS: Sixty two patients consecutively admitted to a teaching hospital, from January 1992 to December 1995 were included in the study. We studied preoperative, intraoperative and postoperative features looking for their relationship with the outcome. The ultimate outcome was evaluated by means of Glasgow Outcome Scale on discharge and 6 months later. RESULTS: Smoking (p = 0.0001) and arterial hypertension (AHT) (p = 0.0186) were more frequent in these patients than in general population, but without relationship to the outcome as with the age of the clinical status on admission. The greatest statistical relationship was found between the level of consciousness on postoperative awakening (measured by the Hunt and Hess scale), and the outcome (p = 2.53 x 10(-8). From our results we made an algorithm that correctly assigned 92% of studied patients to their outcome. CONCLUSIONS: All patients admitted on with aneurysm SAH deserve intensive care treatment besides their clinical grade. The level of consciousness on postoperative awakening was a good outcome predictor.

Adult↗
PubMed1998

Liver conditioning after cardiac arrest: the use of normothermic recirculation in an experimental animal model.

The aim of this study was to compare the possible role of normothermic recirculation with the role of liver transplants from non-heart-beating donor pigs after 20 min of cardiac arrest. Three groups were studied, of which two were control groups: group 1, in which the liver was harvested from a heart-beating donor; group 2, in which the liver was harvested after a period of cardiac arrest followed by total body cooling; and group 3, in which the liver was procured as in group 2, but including a period of 30 min of cardiopulmonary bypass and tissue oxygenation at 37 degrees C before total body cooling. Survival at 5 days; endothelial (hyaluronic acid) and hepatocellular damage (AST, ALT, and alpha-GST); adenine nucleotides (energy charge), and histological changes were evaluated. Normothermic recirculation during 30 min showed a significant effect on survival (p = .03), endothelial damage (p < .05), and histological changes after reperfusion (p = .04). Cardiopulmonary bypass significantly increased the energy charge during the normothermic recirculation period (p = .001). Moreover, this study shows that a significant survival (100%) can be achieved with a liver allograft after 20 min of cardiac arrest. Although the liver suffers a major insult in terms of endothelial damage and hepatocellular damage, lesions caused by the ischemic injury are reversible. Histological changes also indicate lesion reversibility, since they almost disappear after 5 days.

Adenine Nucleotides↗
PubMed1998

Identification of a Drosophila presenilin homologue: evidence of alternatively spliced forms.

Some cases of Alzheimer's disease are inherited as a dominant trait in humans. To date, mutations in three genes account for some of them: the amyloid precursor protein (APP) and presenilins 1 and 2 (PS-1 and PS-2, respectively). The function of the presenilins is still unclear, although they belong to a transmembrane protein-gene family, probably involved in some signaling pathway. We report here the isolation of the Drosophila presenilin homologue using the human PS-1 and PS-2 cDNAs as probes. Only one single gene has been detected in the Drosophila genome and evidence for alternatively spliced forms is presented and compared to the isoforms reported in humans. Temporal and spatial expression has been assessed by Northern blot and in situ hybridization on embryos of different developmental stages.

Alternative Splicing↗
PubMed1998

[Analysis of the current status of neuroanesthesia in Spain using a national survey].

OBJECTIVES: Advances in complementary diagnostic explorations, surgical support technology and the complexity of neurophysiological monitoring require anesthesiologists to acquire specific knowledge for dealing with neurosurgery. We aimed to study the implantation of new anesthetic-surgical techniques in the field of neurosurgery, and the state of neuroanesthesia as a subspecialty in Spain. MATERIAL AND METHODS: A 20-item postal questionnaire sent to anesthesiology department heads of Spanish hospitals with neurosurgery teams. RESULTS: We received responses from 62% of the hospitals surveyed. Of these, 69% performed stereotaxic surgery, 30% functional cerebral surgery (for Parkinson's disease and epilepsy) and 21% offered neuroendoscopy. In 38% of the hospitals cerebral metabolism was monitored (hemoglobin oxygen saturation in the jugular or regional cerebral oxygen saturation) and/or cerebral electrophysiology (electroencephalogram, evoked potentials) and in 23.8% flows and pressures were measured (transcranial precordial and/or tracheoesophageal Doppler). Anesthesiologists specializing in neurosurgery are present in 62% of the hospitals. Interventionist neuroradiology is performed in 57%. It was noteworthy that 14.3% do not regularly have an anesthesiologist present during such high risk procedures. CONCLUSIONS: Although most centers continue performing "classical" neurosurgery with standard monitoring, a substantial proportion of hospitals (38%) show evidence of advancing in anesthetic techniques for neurosurgery in Spain. Anesthesia for neurosurgery as a subspecialty is available in 62% of the responding hospitals.

Anesthesia↗