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Biomedical subjects

M J Pérez

Publications and source records attributed to M J Pérez.

At least 19 recordsLinked to original sources
PubMed2006

Lipid and fatty acid content in wild white seabream (Diplodus sargus) broodstock at different stages of the reproductive cycle.

The lipid and fatty acid content of the gonads, liver and muscle of wild white seabream males and females was studied at different stages of the reproductive cycle. Samples were taken from mature white seabream at pre-spawning (November), mid-spawning (March) and post-spawning (June) stages. The results showed that lipid accumulates in gonads and muscle from November to March. The gonadosomatic index (GSI) was also increased during this period. Male gonads showed a greater increase in polar lipid (PL) than neutral (NL), while female gonads displayed the reverse. The increase in both neutral and polar lipid was higher in the muscle of males than in females. In the same period, male livers showed no changes either in lipid content or the hepatosomatic index (HSI), while female livers registered an increase in both lipid content and HSI. Between March and June, in both males and females, total, neutral and polar lipid decreased sharply in the gonads and muscle. Muscular lipid content reduction was more pronounced in males than females. On the other hand, the lipid content of the liver in males and females remained relatively constant. In general terms, the amounts of major fatty acids (16:0, 18:1n-9, 20:5n-3 and 22:6n-3) in gonadal and muscular polar and neutral lipid in both males and females increased from November to March and declined thereafter. Variations of the liver fatty acid content were less extreme. In the period from mid-spawning to post-spawning, the presence of 20:4n-6 in polar and neutral lipid increased to a notable extent in all organs studied.

Animals↗
PubMed2006

Postoperative infections after major heart surgery and prevention of ventilator-associated pneumonia: a one-day European prevalence study (ESGNI-008).

Few data have been published on the prevalence of postoperative infection in patients undergoing major heart surgery (MHS). The degree of compliance with standard measures used to prevent them is unknown. This study assessed the prevalence of infections, particularly ventilator-associated pneumonia (VAP), in patients undergoing MHS in 42 institutions from 13 European countries. On the study day, there were 321 postoperative MHS patients, of whom 164 (51%) were mechanically ventilated. The overall prevalence of infection was 26.8%. Lower respiratory tract infections represented 57% of all the infections present on the study day. Other infections included intravenous-catheter-related bloodstream infections (2.8%), surgical site infections (2.2%), urinary tract infections (0.9%) and postoperative mediastinitis (0.9%). Of the mechanically ventilated patients, 55 (33.5%) were not being nursed in a semi-recumbent position, 36 (22%) had heat-moisture exchangers with no antibacterial filters, and intracuff pressure was not monitored in 78 patients (47.6%). Only 13 patients (8%) were given continuous subglottic suctioning, 64 patients (39%) did not receive postural oscillation, and gastric overdistension was not actively prevented in 23 patients (14%). In conclusion, these data from intensive care units across Europe provide information on postoperative infections in an important subset of the patient population, and stress the need for active interventions to prevent VAP in patients undergoing MHS.

Cardiac Surgical Procedures↗
PubMed2006

Infections following major heart surgery in European intensive care units: there is room for improvement (ESGNI 007 Study).

Patients undergoing major heart surgery (MHS) may be at increased risk for nosocomial infections. To assess the incidence and type of infections in MHS patients in European intensive care units (ICUs) and their quality of care, a questionnaire was sent to a selection of MHS ICUs in Europe. Seventeen hospitals from seven European countries participated. Overall, 53% of the ICUs received patients only for MHS and the other 47% were mixed. During the study period, 11 915 patients underwent MHS and 1181 (9.9%) developed one or more nosocomial infections. Ventilator-associated pneumonia (VAP) was the most common infection [median 3.8%; interquartile range (IQR) 1.8-4.9], followed by surgical wound infection (median 1.6%; IQR 0.8-2.3), catheter-related bloodstream infection (median 1.3%; IQR 0.8-2.1), mediastinitis (median 1.1%; IQR 0.4-1.6), urinary tract infection (median 0.6; IQR 0.4-1.4) and nosocomial endocarditis (median 0.2%; IQR 0.0-0.9). Median mortality was 4.7% (IQR 2.7-8.4) and median infection-related mortality was 1% (IQR 0.5-2.7). Regarding VAP, 18% of the ICUs did not routinely pursue a diagnosis. Microbiological information was quantitative in 35% of cases and exclusively qualitative in 65% of cases. An infectious disease specialist was regularly involved in VAP management in only 35% of the ICUs, and the therapeutic approach to VAP involved de-escalation in 59% of the ICUs. MHS ICUs in Europe still have a high rate of postoperative infections. Well-recognized routine practices for the diagnosis and treatment of VAP are not implemented regularly in many European institutions.

Cardiac Surgical Procedures↗
PubMed2005

Effects of 5-hydroxydecanoate and ischemic preconditioning on the ischemic-reperfused heart of fed and fasted rats.

This investigation aimed to assess whether the mitochondrial ATP-sensitive potassium channel blocker 5-hydroxydecanoate (5-HD) could abolish the protection conferred by fasting and ischemic preconditioning (IPC) and to ascertain whether these effects are associated with glycogen breakdown and glycolytic activity. Langendorff perfused hearts of fed and 24-h fasted rats were exposed to 25 min ischemia plus 30 min reperfusion. IPC was achieved by a 3 min ischemia plus a 5 min reperfusion cycle. 5-HD (100 microM) perfusion begun 5 min before IPC or 13 min before sustained ischemia in the non preconditioned groups. Fasting improved the reperfusion recovery of contraction, decreased the contracture and the lactate production, increased glycogenolysis and did not affect the percentage of viable tissue. 5-HD abolished the effects of fasting on the contractile recovery but did not affect the contracture. 5-HD decreased the lactate production in the fed group, increased the preischemic glycogen content in both nutritional groups and did not affect the ischemic glycogen fall. IPC improved the contractile function but prevented the contracture only in the fed group, reduced lactate accumulation and glycogenolysis and evoked an increase of the viable tissue. 5-HD abolished the effects of IPC on the contractile recovery and did not affect its effect on the contracture, lactate production, glycogenolysis and viable tissue. These data suggest that the mitocondrial ATP-sensitive potassium channel is involved in the effects of fasting and IPC on the contractile function but the other cardioprotective and metabolic effects appear evoked through other mechanisms. Also suggest that besides the inhibition of the mitochondrial potassium channel, other mechanisms mediate the effects of 5-HD.

Animals↗
PubMed2003

Vibrio lentus associated with diseased wild octopus (Octopus vulgaris).

Studies were undertaken to identify the bacteria involved in a disease of wild octopus (Octopus vulgaris). Signs of the disease include round hard lesions in the arms or head mantle, leading, in advanced cases, to the loss of skin and the exposure of the muscle beneath. Bacterial strains isolated from sterile organs have been evaluated taxonomically and by experimental infections. Different phenotypes and ribotypes of Vibrio lentus were identified. Experimental infection by bath challenge demonstrated that V. lentus was able to reproduce the skin lesions, colonize the internal organs and induce mortality in healthy octopuses. V. lentus was re-isolated from the skin lesions and gill heart of dead octopuses, as confirmed by numerical taxonomy analysis. No effects were produced in sea bream or turbot by intraperitoneal injection of the bacterial isolate.

Animals↗
PubMed2003

Characterization of Vibrio strains isolated from turbot (Scophthalmus maximus) culture by phenotypic analysis, ribotyping and 16S rRNA gene sequence comparison.

AIM: The aim of the present study was to clarify the taxonomic status of Vibrio strains isolated from an aquaculture system and to compare the results of the identifications made by phenotypic and molecular methods. METHODS AND RESULTS: Fifty-one Vibrio strains isolated from a turbot (Scophthalmus maximus) aquaculture system were characterized by ribotyping and 16S rRNA gene sequencing. The strains had been identified phenotypically in a previous numerical taxonomy analysis as Vibrio anguillarum, V. mediterranei, V. splendidus, V. aestuarianus, V. ordalii, V. fischeri and V. scophthalmi. Cluster analysis of ribotype patterns showed that the strains were separated into two main groups: V. splendidus-V. lentus and V. scophthalmi groups. The use of 16S rRNA gene sequence allowed differentiation among V. splendidus biovar I and V. lentus strains. CONCLUSIONS: The molecular methods identified strains of V. splendidus biovar I, V. lentus and V. scophthalmi, showing discrepancies with phenotypic characterization. SIGNIFICANCE AND IMPACT OF THE STUDY: The molecular methods, as 16S rRNA gene sequence analysis, are necessary for the identification of phenotypically close species to avoid mis-identifications. Interestingly, this is the first report of V. lentus strains associated to turbot culture.

Animals↗
PubMed2002

Purification and partial characterisation of a fish lethal extracellular protease from Vibrio pelagius.

The purification, characterisation and lethal effect of an extracellular protease present in the extracellular products (ECPs) of a pathogenic Vibrio pelagius (7P) strain are described. The extracellular protease was purified by size-exclusion high-performance liquid chromatography and characterised by enzymatic assays. The lethal effect was evaluated by injection into fish. The native protease had a molecular mass of 39 kDa, was active on casein and L-leucyl-beta-naphthylamide (LNA) and its metalloprotease nature was shown by the LNA inhibition profile. Kinetic studies on the hydrolysis of casein and LNA confirmed a competitive inhibition of one substrate with respect to the other. The temperature assays showed that both aminopeptidolytic and caseinolytic activities were labile at 70 degrees C for 3 min. The N-terminal amino acid sequence of 7P protease revealed a high degree of homology with other metalloproteases of Vibrio species that are implicated in virulence. The purified 7P protease showed an LD(50) of 1.77 microgprotein/g fish for turbot. The quick lethal effect (<24h) and the macroscopic damage (external haemorrhagic areas, principally on fins and mouth, petechial haemorrhages in internal organs, but with no external or internal apparent necrotic areas) detected in the host were similar to those obtained by injection of total ECP and live cells of 7P strain. An extracellular protease with endopeptidolytic and exopeptidolytic activities, responsible for the lethal effect of ECP and clinical signs of vibriosis in turbot was purified from a pathogenic V. pelagius (7P) strain.

Amino Acid Sequence↗
PubMed2002

A 45-kDa acetylcholinesterase protoxin of Aeromonas hydrophila: purification and immunogenicity in fish.

A rabbit antiserum to the 15-kDa acetylcholinesterase toxin neutralised the lethal effect of the 15-kDa toxin of Aeromonas hydrophila when injected into trout. However, immunisation of fish with the 15-kDa toxoid failed to induce an antibody response, and a higher molecular mass form of this toxin was purified from the extracellular products with the aim of inducing an immune response in fish. The optimal conditions for production of extracellular products by A. hydrophila strain B32 were studied to increase the concentration of this protoxin. The extracellular products were fractionated by molecular exclusion chromatography to yield a purified protoxin with an estimated molecular mass of 45 kDa by SDS-PAGE and which gave a positive reaction in Western blotting with the rabbit anti-15-kDa toxin serum. Since the 45-kDa protoxin showed lower specific acetylcholinesterase activity than the active 15-kDa toxin, the behaviour of the active site was studied using specific inhibitors. This 45-kDa protoxin was 13.3-fold less toxic than the 15-kDa toxin and induced antibody production in fish.

Acetylcholinesterase↗
PubMed2001

Spin trapping agents (Tempol and POBN) protect HepG2 cells overexpressing CYP2E1 against arachidonic acid toxicity.

Polyunsaturated fatty acids such as arachidonic acid were previously shown to be toxic to HepG2 cells expressing CYP2E1 by a mechanism involving oxidative stress and lipid peroxidation. This study investigated the effects of the spin trapping agents Tempol and POBN on the arachidonic acid toxicity. Arachidonic acid caused toxicity and induced lipid peroxidation and mitochondrial membrane damage in cells overexpressing CYP2E1 but had little or no effect in control cells not expressing CYP2E1. The toxicity appeared to be both apoptotic and necrotic in nature. 4-Hydroxy-[2,2,6,6-tetramethylpiperidine-1-oxyl] (Tempol) and alpha-(4-pyridyl-1-oxide)-N-tert-butyl nitrone (POBN) protected against the decrease in cell viability and the apoptosis and necrosis. These spin traps prevented the enhanced lipid peroxidation and the loss of mitochondrial membrane potential. Tempol and POBN had little or no effect on cellular viability or on CYP2E1 activity at concentrations which were protective. It is proposed that elevated production of reactive oxygen intermediates by cells expressing CYP2E1 can cause lipid peroxidation, which subsequently damages the mitochondrial membrane leading to a loss in cell viability when the cells are enriched with arachidonic acid. Tempol and POBN, which scavenge various radical intermediates, prevent in this way the enhanced lipid peroxidation, mitochondrial dysfunction, and the cell toxicity. Since oxidative stress appears to play a key role in ethanol hepatotoxicity, it may be of interest to evaluate whether such spin trapping agents are useful candidates for the prevention or improvement of ethanol-induced liver injury.

Antioxidants↗
PubMed2000

Quality of the information contained in the minimum basic data set: results from an evaluation in eight hospitals.

To assess the quality of the information included in the minimum basic data set (MBDS) of the eight public hospitals of the Murcia region in order to ascertain what should be improved to be valid and reliable. An external encoder performed a recoding of a random sample of hospital discharges, using the patients hospital records and comparing afterwards the information obtained with the one reflected in the MBDS databases. Quality was assessed using 12 criteria. The reviewed discharges sample consisted at least of 96 cases per hospital (Type I error = 0.05, Type II = 0.10, for the most unfavorable case). A total of 796 cases were reviewed. The MBDS disagreement percentages with the patient record data were higher for the clinical data, with 41.6% for the main diagnosis and 33.5% for the main surgical procedure, being in both cases higher in those hospitals that had used to codify just the discharge record with regard to those that did so with the complete patient record. The variation rate in the diagnosis-related group (DRG) assignment was of 29.6%, and there was a decrease in the case-mix index of 1.07397 when reviewing with the patient record to 1.05555 in the MBDS. Within the administrative data, the highest disagreement rate was for the physician that signs the discharge (60.5%) and the patient's address (31.6%). In many of these assessed aspects there are significant differences between hospitals. A reliability problem was identified in the collected data, which mainly affects the clinical variables. It is therefore advisable to carefully assess the use of this information (both the MBDS directly as well as its grouping through the use of patient classification systems), and the indicators derived from it as its quality is not guaranteed. Systematic assessment and quality control of the MBDS production is advised.

Databases, Factual↗
PubMed1999

Endothelin stimulates tyrosine phosphorylation of p125FAK and p130Cas in rat cerebral cortex.

Stimulation of rat cerebral cortex with endothelin-1 (ET-1) caused an increase in the tyrosine phosphorylation of several proteins. Two of these phosphoproteins were identified by the immunoprecipitation assays as being the focal adhesion kinase p125FAK and crk-associated substrate p130Cas. This effect was time- and dose-dependent, with an EC50 value of 3.9 x 10(-8) M. In addition, the cerebral cortex ET receptor subtype involved in this action was determined by using BQ-123 and BQ-788, which are ET(A) and ET(B) receptor antagonists respectively. Our results indicate that the ET-1 effect on protein tyrosine phosphorylation occurred through ET(B) receptors. The requirement for extracellular Ca2+ on ET-1 action was also studied. ET-1-stimulated tyrosine phosphorylation of both p125FAK and p130Cas was abolished in the absence of external Ca2+ or in the presence of nimodipine, a Ca2+ channel-blocker. These results suggest that the ET-1-stimulated protein tyrosine phosphorylation was secondary to Ca2+ influx through the dihydropyridine Ca2+-channel. In slices where protein kinase C was inhibited, ET-1-stimulated tyrosine phosphorylation of both proteins was reduced. These results indicate that ET-1 modulates the tyrosine phosphorylation of specific proteins, which may be involved in adhesion processes in the brain.

Animals↗
PubMed1999

Numerical taxonomy of gram-negative, facultative anaerobic bacteria isolated from skin of turbot (Scophthalmus maximus) and surrounding water.

A numerical taxonomic study of 473 gram negative heterotrophic facultative anaerobic bacteria isolated from skin of turbot (Scophthalmus maximus) and its culture water was performed. The study included 53 type and reference strains belonging to the genera Vibrio, Aeromonas and Listonella. The strains were characterized using 90 tests and data were examined by Simple Matching coefficient (S(SM)) and Jaccard coefficient (S(J)). UPGMA (unweighted pair group method, arithmetic average) defined 66 phena at S(SM) values > or = 84% and 27 groups at S(SM) > or = 80%. Six phena were defined as Vibrio albensis, V. (Listonella) anguillarum, V. splendidus biotype I, V. fischeri, V. ordalii and V. scophthalmi including reference strains. Some groups clustered different phena for one species, although others as the V. anguillarum related strains and inactive Vibro group required S(SM) > or = 84% to define species. More studies are necessary to identify the Vibrio spp. strains and to confirm some species identifications.

Animals↗
PubMed1999

Characterization by numerical taxonomy and ribotyping of Vibrio splendidus biovar I and Vibrio scophthalmi strains associated with turbot cultures.

Twelve Vibrio strains were examined phenotypically in 91 biochemical characters and genotypically by ribotyping. Ten were isolated from sea water and two from diseased turbot (Scophthalmus maximus). All isolates originated from one experimental system located in Ría de Vigo (Galicia, north-west Spain). Different type strains were used for comparative purposes. The taxonomic position was analysed with the NTSYST-pc and similarities among strains were calculated by the Simple Matching coefficient (SSM). rRNA gene restriction patterns were performed with the HindIII enzyme. The SSM coefficient separated the 12 Vibrio strains into two groups which included strains that showed a SSM coefficient quite similar to V. splendidus biovar 1 (ATCC 33125) and V. scophthalmi (CECT 4638). None of 91 phenotypical characters were specific in distinguishing both species. The ribotyping confirmed the taxonomic classification of strains. The pathogenicity of each strain was evaluated; 10 environmental strains were avirulent and two, isolated from diseased turbot, were virulent. Different biotypes and ribotypes were found among the avirulent isolates. This work showed ribotyping to be a valuable tool for identification and confirmed the necessity of extending the ribotype database within closely related Vibrio species in order to clarify the taxonomic position.

Animals↗
PubMed1998

Siderophore production by Aeromonas salmonicida subsp. salmonicida. Lack of strain specificity.

Siderophore production, presence of iron-regulated outer membrane proteins and siderophore specificity was determined among 17 isolates of Aeromonas salmonicida subsp. salmonicida obtained from Spain and Scotland. All grew in the presence of ethylenediamine di(o-hydroxyphenylacetic acid) (EDDA) and siderophore production was detected using chrome azurol S (CAS) agar, confirming the presence of a high-affinity siderophore iron-uptake mechanism. The Arnow test confirmed that all isolates produced a catechol siderophore. Cross-feeding assays with indicator bacteria showed the absence of anguibactin, enterobactin, 2,3-dihydroxybenzoic acid (DHBA) and the hydroxamate siderophore, aerobactin, in the iron-restricted supernants of a representative isolate which cross fed 15/17 A. salmonicida isolates tested. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed the presence of the same 2 major iron-regulated outer membrane proteins (IROMPs) in all isolates when grown in iron-restricted conditions and siderophore strain specificity as assessed by cross-feeding experiments was not apparent. Thus, with respect to IROMP and siderophore production A. salmonicida appears to be a homogeneous species.

Aeromonas↗
PubMed1998

The acetylcholinesterase ichthyotoxin is a common component in the extracellular products of Vibrionaceae strains.

In previous work, it was reported that a strain of Aeromonas hydrophila (B32) produces the most potent lethal toxin with neurotoxic activity described so far for fish. In the present study, the presence and distribution of this acetylcholinesterase toxin lethal for fish were determined in extracellular products (ECP) of 42 Vibrionaceae strains using both immunological and colorimetric methods. This neurotoxin was shown to be present in the majority of the ECP from the Aeromonas and Vibrio strains tested and is responsible for the specific acetylcholinesterase activity. Also, although the Western blot and Ouchterlony techniques are valid as qualitative methods for the detection of this toxin, the Western blot procedure was 100-fold more sensitive than the Ouchterlony technique.

Acetylcholinesterase↗
PubMed1998

Vividness of visual and haptic imagery of movement.

This study investigated the relationships between visual and haptic imagery of movement. A total of 338 subjects, all university students aged between 18 and 26 years, completed the Vividness of Movement Imagery Questionnaire, which evaluates capacity for visual imaging, and a modification of this questionnaire, the Vividness of Haptic Movement Imagery Questionnaire, designed to evaluate capacity for haptic imaging. Scores on the two questionnaires were significantly correlated .60.

Adolescent↗
PubMed1997

Mutation analysis of the p53, APC, and p16 genes in the Barrett's oesophagus, dysplasia, and adenocarcinoma.

AIMS: To study the loss of heterozygosity and the presence of mutations at the p53, p16/CDKN2, and APC genes in Barrett's oesophagus, low grade dysplastic oesophageal epithelium, and adenocarcinoma of the oesophagus; to relate the presence of alterations at these genes with the progression from Barrett's oesophagus to adenocarcinoma. METHODS: DNA was extracted from paraffin blocks containing tissue from Barrett's oesophagus (12 samples), low grade dysplasia (15 cases), and adenocarcinoma (14 cases). Loss of heterozygosity (LOH) at the p53, p16, and APC genes was determined by comparing the autoradiographic patterns of several microsatellite markers between the normal tissue and the malignant tissue counterpart. SSCP was used to determine the presence of mutations at p53 (exons 5 to 8), p16 (exon 2), and APC. Homozygous deletion of the p16 gene was defined through polymerase chain reaction followed by Southern blot. RESULTS: LOH at the p53, p16, and APC genes was not observed in Barrett's oesophagus without dysplasia, and increased to 90% (p53), 89% (p16), and 60% (APC) in the adenocarcinomas. The p53 gene was mutated in only two adenocarcinomas (codons 175 and 245). In one case a mutation at the APC gene (codon 1297) was found. No patient had mutation at the second exon of p16. However, this gene was homozygously deleted in three of the 12 adenocarcinomas. CONCLUSIONS: The tumour suppressor genes p53, p16, and APC are often deleted in adenocarcinomas derived from Barrett's oesophagus. Mutations at these genes are also found in the adenocarcinomas, including the homozygous deletion of the p16 gene. However, the absence of genetic alterations in the Barrett's oesophagus and the low grade dysplastic epithelia suggest that mutations at these genes develop later in the progression from Barrett's oesophagus to adenocarcinoma.

Adenocarcinoma↗