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Biomedical subjects

A Prat

Publications and source records attributed to A Prat.

At least 73 records · Page 4Linked to original sources
PubMed1997

Intramural hematoma of the thoracic aorta: precursor sign to thoracic aortic dissection.

A 60-year-old man was admitted at his local hospital for persistent chest pain and suspicion of aortic dissection. No evidence of aortic dissection or intimal disruption was noted by means of computed tomography and transesophageal echocardiography. A localized intramural hematoma of the ascending aorta was found. He was first treated medically and remained asymptomatic for 8 days when he developed a new episode of chest pain. He was found to have an acute type A dissection by computed tomography. He underwent graft replacement of the ascending aorta and had an uneventful post-operative course. This case report describes the development of true aortic dissection in a patient who previously had a localized intramural hematoma.

Aortic Dissection↗
PubMed1997

Expression and retinoid modulation of N-arginine dibasic convertase and an aminopeptidase-B in human neuroblastoma cell lines.

Under retinoic acid exposure, the three SK-N-BE(2)-derived human neuroblastoma cell lines, BE(2)-NA, BE(2)-SA and BE(2)-M17 undergo mainly differentiation, apoptosis or continue to proliferate, respectively. We have used this model system to study the modulation of the transcriptional expression of putative processing enzymes, two novel metallopeptidases; i.e. N-arginine dibasic convertase (NRD convertase; EC 3.4,24,61) and an aminopeptidase-B after exposure of the cells either to retinoic acid or to synthetic retinoid analogs. The data indicate that the two respective enzymes are differently modulated in the various cell lines. Whereas aminopeptidase-B expression is enhanced in most cases, NRD convertase appears to undergo opposite regulation in proliferating versus differentiating neuroblastoma cells. It is concluded that both genes might contain retinoic acid regulatory elements (RARE) in their promoters.

Aminopeptidases↗
PubMed1997

Low apolipoprotein E epsilon4 allele frequency in the population of Catalonia (Spain) determined by PCR-RFLP and Laser fluorescent sequencer.

Specific apolipoprotein E alleles have been associated in the last few years with several diseases using appropriate controls. However, these control groups are rarely representative of the general population since they correspond either to aged or healthy control groups (and thus depleted of pathological alleles). For this reason it is difficult at present to compare population allelic frequencies in different countries. In order to provide this essential basic data representative of the general population, in this work we have determined the distribution of apolipoprotein E alleles in 226 individuals from the population of Catalonia (Spain) sampled with the main purpose of paternity testing. The allelic frequencies are: epsilon2 = 0.064, epsilon3 = 0.810 and epsilon4 = 0.126, predicting a lower incidence of Alzheimer disease and possibly also of other pathologies where this allele is a risk factor.

Adult↗
PubMed1997

NRD convertase and aminopeptidase B: two processing metallopeptidases with a selectivity for basic residues.

An endoprotease and an aminopeptidase B were isolated from rat testis and characterized. The first one is a metalloendopeptidase of 1161 residues which contains a canonical HXXEHX76E Zn(2+)-binding site and an acidic stretch of 71 amino acids containing 79% of Glu and Asp. It exhibits an in vitro selectivity for peptide bonds at the N-terminus of Arg (R) moieties in dibasic sites and was thus called NRD convertase (Nardilysin: EC 3.4.24.61). It belongs to the pitrilysin family and shows 24 and 34% identity with E. coli protease III (EC 3.4.24.54) and insulysin (EC 3.4.24.55) respectively. The aminopeptidase B component is a 72 kDa metalloexopeptidase which is able to remove Lys and Arg residues from naphtylamide derivatives and from the N-terminus of various peptide substrates. A combination of biochemical and immunochemical studies revealed its ubiquitous character. In the testis, both enzymes are highly expressed at late stages of spermatogenesis and NRD convertase expression is exclusively restricted to the germ cells. The subcellular localization of both enzymes supports the involvement of aminopeptidase B in processing events associated with the secretory pathway but led to new hypothesis on the possible physiological role(s) of NRD convertase.

Amino Acid Sequence↗
PubMed1996

[Prevalence of hepatitis B and hepatitis A virus infection among health sciences students in Catalonia, Spain].

BACKGROUND: To know current hepatitis B (HBV) and hepatitis A (HAV) infection status among a group of health sciences students during 1990-1993 period. SUBJECTS AND METHODS SUBJECTS: 1,734 health sciences students during 1990-1991, 1992-1993 and 1993-1994 academic years. MAIN OUTCOME MEASURES: demographic variables, vaccination history against HAV and HBV viruses, anti-HBc and anti-HAV antibody titres (ELISA kits). RESULTS: 1,734 subjects aged 22.5 +/- 2.9 years (75% women) were included. Anti-HBc total cumulated prevalence during the three year period was 2.5% (CI 95%, 1.9%-3.4%). Anti-HAV total cumulated prevalence during the three year period was 13.9% (CI 95%: 11.4%-16.8%). No statistical significant association between antibody prevalence and both age sex was found. CONCLUSIONS: Low prevalence, and thus, high susceptibility to HBV and HAV infection was found. We stress the importance of systematic vaccination among health sciences students not previously engaged in universal vaccination programmes. We also point out the need for further analysis upon the utility of combined HB/HA vaccine as an alternative to antihepatitis B universal vaccination programmes among adolescent cohorts.

Adult↗
PubMed1996

[Susceptibility to measles, rubella and parotitis in young adults].

BACKGROUND: The aim of this study was to know the prevalence of antibodies against measles, rubella and parotiditis in young adults. METHODS: The study was carried out in health care students during the academic year of 1992-1993. Demographic and geographic variables were obtained as were vaccination and history of diseases. Antibodies against measles, rubella, and parotiditis were determined by ELISA techniques with commercial reagents. RESULTS: Three hundred and six individuals of 21.3 +/- 2.2 years (range 17-36 years) with 27.5% being males were studied. Past history of measles, rubella and parotiditis was reported in 43.5, 30.7 and 37.3%, respectively, with vaccination being 23.2, 43.8 and 20.6%, respectively. The prevalence of antibodies was 93.1% (measles), 96.4% (rubella) and 92.1% (parotiditis). CONCLUSIONS: The prevalence of infection of measles, rubella and parotiditis in the young population studied is mainly due to infection by wild type virus. The foreseeable growth of susceptibility groups in this population which should be adequately evaluated by extensive seroepidemiologic questionnaires, favors the appearance of epidemic outbreaks. The use of the triple viral vaccine is suggested as an alternative to rubella vaccination in presumable susceptible young women.

Adolescent↗
PubMed1996

Fatal infection of coronary stent implantation.

Among systemic infections occurring after percutaneous transluminal coronary angioplasty (PTCA) and coronary stent implantation, septic cardiac complications are rare. We report a new case of infective aneurysm of the left anterior descending coronary artery (LAD) following stent implantation. Infective mitral endocarditis due to Pseudomonas aeruginosa occurring a few weeks after stenting led to search for stent infection. Coronary angiography revealed a saccular aneurysm of the LAD. Despite surgical repair, a fatal outcome resulted.

Angioplasty, Balloon, Coronary↗
PubMed1996

Prevention and control of nosocomial infections in Spain: current problems and future trends.

Spain is a state member of the European Union, with more than 180,000 hospital beds and 800 public and private institutions. Only 6.9% of our gross national product is devoted to health expenditures. All citizens receive free health care through the National Health System. This system has given increasing attention to the prevention and control of nosocomial infections since 1986. In this article, results of serial prevalence surveys of antibiotic use and resistance patterns of microorganisms isolated from nosocomial infections are discussed. The needs for future development of infection control and quality assurance training programs in Spain also are discussed. Overall, a clinically and epidemiologically oriented approach to infection control is preferred, with greater emphasis in the role of infection control practitioners and infection control committees.

Anti-Bacterial Agents↗
PubMed1996

NRD convertase: a putative processing endoprotease associated with the axoneme and the manchette in late spermatids.

N-arginine dibasic convertase is a novel metalloendopeptidase which selectively cleaves at the N terminus of arginine residues in paired basic amino acids. Although present in brain and several other tissues, NRD convertase is particularly abundant in testis, where its expression appeared to be restricted to germ cells. Low levels of both mRNA and its corresponding protein were detected early in spermatogenesis. However, a marked accumulation of the protein was observed during late steps (14 to 19) of spermiogenesis. By electron microscopy, the NRD convertase immunoreactivity was localized in the cytoplasm of elongating and elongated spermatids, with a noticeable concentration at the level of two microtubular structures, i.e. the manchette and the axoneme. These observations strongly support the hypothesis that NRD convertase is involved in processing events potentially associated with the morphological transformations occurring during spermiogenesis.

Animals↗
PubMed1995

Characterization of the tachykinin receptors involved in spinal and supraspinal cardiovascular regulation.

The pharmacological characterization of the tachykinin receptors involved in spinal and supraspinal cardiovascular regulation is reviewed in this report. In conscious rats, substance P (SP), neurokinin A (NKA), neurokinin B (NKB), neuropeptide K (NPK), and neuropeptide gamma (NP gamma) were injected either intrathecally (i.t.) or intracerebroventricularly (i.c.v.), and their effects were assessed on mean arterial blood pressure (MAP) and heart rate (HR). Moreover, selective antagonists for NK1 ((+/-)-CP-96045 and RP-67580), NK2 (SR-48968), and NK3 (R-486) receptors were tested against the agonists. I.t. tachykinins elicited dose-dependent increases in MAP and HR (NPK > NP gamma > SP > NKA > NKB). The cardiovascular response to i.t. SP, NPK, and NP gamma was significantly attenuated by the prior i.t. administration of (+/-)-CP-96345 and RP-67580 but not by SR-48968 and R-486. By the i.c.v. route, tachykinins also elicited pressor and tachycardiac responses dose dependently (NPK > NP gamma > SP > NKA > NKB). Senktide and [MePhe7]NKB, two NK3-selective agonists, were slightly more potent than NKB on both parameters. Whereas the cardiovascular response to NPK was largely blocked by (+/-)-CP-96345 and RP-67580, that to SP was reduced by 40-50%. This treatment had no effect on the cardiovascular response to NKA and [MePhe7]NKB. Conversely, SR-48968 reduced by 40-50% the NKA-induced cardiovascular changes without affecting the central mediated effects of NPK, SP, and [MePhe7]NKB. However, when coadministered, RP-67580 and SR-48968 abolished the effects to SP and NKA while leaving untouched those induced by [MePhe7]NKB. Finally, the central effects mediated by [MePhe7]NKB, senktide, and NKB were blocked by R-486. These findings suggest that the i.t. action of tachykinins on the rat cardiovascular system is mediated by a NK1 receptor in the spinal cord, while NK1, NK2, and NK3 receptors are likely involved in the supraspinal (hypothalamus) effects of these neuropeptides. It is also concluded that NPK is a pure and powerful NK1 agonist, in contrast to SP and NKA, which are not selective for NK1 and NK2 receptors, respectively.

Amino Acid Sequence↗
PubMed1995

Appropriateness of admissions and hospitalization days in an acute-care teaching hospital.

A cross-sectional study was made of the appropriateness of admissions and hospitalization days in an high-technology, acute-care teaching hospital. This 952-bed institution with 31 hospital services is a reference center for the metropolitan area of Barcelona. A systematic random sampling (1:11) of the registers of hospital discharges was carried out during the months of January, February and March 1991 (n = 7,142) excluding discharges from the pediatric, obstetrics and psychiatric departments. A retrospective analysis was made of 639 patients' medical records using the Appropriateness Evaluation Protocol (AEP). The rate of inappropriate hospital admissions was 9.1% (58/639) (95% confidence interval: 6.9-11.5). Inappropriate admissions were primarily attributable to hospitalizations for diagnostic and/or therapeutic services that could have been rendered on an ambulatory basis (70.7% of cases). Overall 29.2% of hospitalization days (1,963/6,731) were inappropriate (95% confidence interval: 28.1-30.3). Inappropriate admissions to hospital, an optimizable health care planning and a conservative physician's attitude (postponed discharge) were the most frequent reasons for unnecessary days of care. The interrater reliability in the use AEP criteria for appropriateness of admission showed a kappa index of 0.5 and that for appropriateness of hospitalization days 0.67. In summary, instruments, such as the AEP protocol, that allow us to determine which patients can be attended at other levels of the health care system and which levels are the most appropriate, are key elements in improving the appropriateness of hospital use in public health care systems.

Acute Disease↗
PubMed1994

N-arginine dibasic convertase, a metalloendopeptidase as a prototype of a class of processing enzymes.

N-Arg dibasic convertase is a metalloendopeptidase from rat brain cortex and testis that cleaves peptide substrates on the N terminus of Arg residues in dibasic stretches. By using both an oligonucleotide and antibodies to screen a rat testis cDNA library, a full-length cDNA was isolated. The sequence contains an open reading frame of 1161 codons corresponding to a protein of 133 kDa that exhibits 35% and 48% similarity with Escherichia coli protease III (pitrilysin, EC 3.4.99.44) and rat or human insulinase (EC 3.4.99.45), respectively. Moreover, the presence of the HXXEH amino acid signature (XX = FL) clearly classifies N-Arg dibasic convertase as a member of the pitrilysin family of zinc-metalloendopeptidases. In addition, a Cys residue that may be responsible for the thiol sensitivity of the insulinase and N-Arg dibasic convertase was proposed. The protein sequence contains a distinctive additional feature consisting of a stretch of 71 acidic amino acids. We hypothesize that this metalloendopeptidase may be a member of a distinct class of processing enzymes.

Amino Acid Sequence↗