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Biomedical subjects

M Ruiz

Publications and source records attributed to M Ruiz.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Evolution of resistance to quinolones in Salmonella enterica in our setting].

Salmonella enterica is mainly associated with acute gastroenteritis; however, it is also associated with other more severe disease processes, for which quinolones are the treatment of choice. We retrospectively studied the evolution of resistance to nalidixic acid and ciprofloxacin of all the clinical isolates of S. enterica from 1992 to 1998 in our hospital environment. A total of 848 strains from feces, blood and other locations were studied. We detected an increase in the resistance to nalidixic acid from 12% in 1992 to 21.3% in 1998, especially in the Enteritidis and Hadar serotypes. We did not detect resistance to ciprofloxacin, but there was in increase in the MIC in the nalidixic acid-resistant strains. Although this is interpreted as sensitive according the the NCCLS criteria, if we apply the cutoff points established by MENSURA, 89.46% of the strains do not fit into this category (S <0.12 mg/l). This puts into question the utility of quinolones in the long-term treatment of severe disease processes produced by this type of strain.

Anti-Infective Agents↗
PubMed1999

[Evolution of resistance to quinolonesin Salmonella enterica in our environment]

Salmonella enterica is mainly associated with acute gastroenteritis; however, it is also associated with other more severe disease processes, for which quinolones are the treatment of choice. We retrospectively studied the evolution of resistance to nalidixic acid and ciprofloxacin of all the clinical isolates of S. enterica from 1992 to 1998 in our hospital environment. A total of 848 strains from feces, blood and other locations were studied. We detected an increase in the resistance to nalidixic acid from 12% in 1992 to 21.3% in 1998, especially in the Enteritidis and Hadar serotypes. We did not detect resistance to ciprofloxacin, but there was in increase in the MIC in the nalidixic acid-resistant strains. Although this is interpreted as sensitive according the the NCCLS criteria, if we apply the cutoff points established by MENSURA, 89.46% of the strains do not fit into this category (S <0.12 mg/l). This puts into question the utility of quinolones in the long-term treatment of severe disease processes produced by this type of strain.

Journal Article↗
PubMed1999

99mTc-tetrofosmin assessment of myocardial perfusion and viability in canine models of coronary occlusion and reperfusion.

UNLABELLED: The goal of this study was to determine whether 99mTc-tetrofosmin can assess regional flow heterogeneity when injected during sustained coronary artery occlusion and to estimate the degree of myocardial salvage and viability during coronary reperfusion. METHODS: In protocol 1, 99mTc-tetrofosmin, 201 TI and microspheres were injected during total left anterior descending (LAD) coronary artery occlusion in five anesthetized open-chested dogs. Protocol 2 dogs underwent LAD occlusion for either 60 min (n = 7) or 180 min (n = 6) followed by 105 min of reperfusion. 99mTc-tetrofosmin (10 mCi), 201TI (1 mCi) and microspheres were injected 90 min after reflow. In both protocols, myocardial 99mTc-tetrofosmin and 201TI activities were quantified from regions of interest on ex vivo images and by in vitro well counting. RESULTS: In protocol 1, there was a linear relationship between 201TI (r = 0.96) and 99mTc-tetrofosmin (r 0.92) activities and microsphere flow during the occlusion. In protocol 2, the LAD/left circumflex (LCx) defect count ratios for 99mTc-tetrofosmin and 201TI from images of myocardial slices were comparable in dogs undergoing either 1 or 3 h of LAD occlusion and 105 min of reperfusion. Similarly, the LAD/LCx in vitro count ratios were comparable between 201TI and 99mTc-tetrofosmin in 1 and 3 h occluded dogs, and significantly lower than the reperfusion flow when these tracers were injected. Uptake of both tracers was depressed to a greater extent in areas of severe ischemic damage. CONCLUSION: These data suggest that administration of 99mTc-tetrofosmin during coronary occlusion accurately delineates the flow heterogeneity. When given after reperfusion, 99mTc-tetrofosmin uptake was significantly reduced in reperfused, infarcted areas and was reflective of viability and the degree of myocardial salvage in addition to reperfusion flow. These experimental studies validate the clinical use of 99mTc-tetrofosmin for assessing persistent coronary artery occlusion, and infarct size and myocardial viability after reperfusion.

Animals↗
PubMed1998

Regional and cellular patterns of reelin mRNA expression in the forebrain of the developing and adult mouse.

The reelin gene encodes an extracellular protein that is crucial for neuronal migration in laminated brain regions. To gain insights into the functions of Reelin, we performed high-resolution in situ hybridization analyses to determine the pattern of reelin expression in the developing forebrain of the mouse. We also performed double-labeling studies with several markers, including calcium-binding proteins, GAD65/67, and neuropeptides, to characterize the neuronal subsets that express reelin transcripts. reelin expression was detected at embryonic day 10 and later in the forebrain, with a distribution that is consistent with the prosomeric model of forebrain regionalization. In the diencephalon, expression was restricted to transverse and longitudinal domains that delineated boundaries between neuromeres. During embryogenesis, reelin was detected in the cerebral cortex in Cajal-Retzius cells but not in the GABAergic neurons of layer I. At prenatal stages, reelin was also expressed in the olfactory bulb, and striatum and in restricted nuclei in the ventral telencephalon, hypothalamus, thalamus, and pretectum. At postnatal stages, reelin transcripts gradually disappeared from Cajal-Retzius cells, at the same time as they appeared in subsets of GABAergic neurons distributed throughout neocortical and hippocampal layers. In other telencephalic and diencephalic regions, reelin expression decreased steadily during the postnatal period. In the adult, there was prominent expression in the olfactory bulb and cerebral cortex, where it was restricted to subsets of GABAergic interneurons that co-expressed calbindin, calretinin, neuropeptide Y, and somatostatin. This complex pattern of cellular and regional expression is consistent with Reelin having multiple roles in brain development and adult brain function.

Age Factors↗
PubMed1998

CC-chemokines enhance the replication of T-tropic strains of HIV-1 in CD4(+) T cells: role of signal transduction.

This study demonstrates that several CC-chemokines, including those that inhibit entry and replication of macrophage-tropic strains of HIV, increase the replication of T cell (T)-tropic strains in CD4(+) T cells. Enhancement of T-tropic HIV replication is observed at early stages of replication, requires signaling through inhibitory guanine nucleotide-binding regulatory (Gi) proteins, and is associated with increased cell surface colocalization of CD4 and the T-tropic HIV coreceptor CXCR4. These findings may further our understanding of the factors that influence the replication and spread of T-tropic strains of HIV in vivo and suggest that the use of cell signaling CC-chemokines as therapeutic agents for the purpose of limiting HIV replication in vivo should be approached with caution.

Anti-HIV Agents↗
PubMed1998

X-linked adrenoleukodystrophy: phenotype distribution and expression of ALDP in Spanish kindreds.

X-linked adrenoleukodystrophy (X-ALD) is a neurodegenerative disorder caused by an impairment in peroxisomal beta-oxidation of very long straight-chain fatty acids (VLCFAs). Six clinical phenotypes have been delineated: childhood cerebral (CCALD), adolescent cerebral (AdolCALD), adult cerebral (ACALD), adrenomyeloneuropathy (AMN), Addison-only (AO), and presymptomatic (PALD). The distribution of phenotypes varies in different countries. We have diagnosed biochemically 60 X-ALD Spanish patients belonging to 48 kindreds. Their phenotypic distribution was: CCALD plus AdolCALD, 33%; ACALD, 16%; AMN, 27%; AO, 12%; and PALD, 12%. These results contrast with the distribution described in other countries, due to a higher prevalence of the ACALD form. Regarding the expression of the protein product (ALDP), we studied 17 kindreds using immunochemical techniques and found absence of ALDP in 84% of cases. We also studied 13 females from 7 negative ALDP kindreds in order to correlate ALDP expression and the carrier status established by VLCFA measurement. In one case with normal VLCFA levels in serum and fibroblasts, we observed mosaicism in ALDP expression. This fact supports the use of this technique for identifying carriers.

ATP Binding Cassette Transporter, Subfamily D, Mem↗
PubMed1998

Oxidative damage, plasma antioxidant capacity, and glucemic control in elderly NIDDM patients.

A study of oxidative damage was made in elderly noninsulin-dependent diabetes mellitus (NIDDM) patients. A statistically significant increase in glucose and fructosamine was found in fasting NIDDM patients, as well as an increase in the oxidation induced by tert-butyl hydroperoxide. The Total Reactive Antioxidant Potential (TRAP) of the plasma was much reduced (p < .02) and the uricemia was unchanged. The erythrocytes of diabetic patients show greater basal oxidation products (p < .05), and the susceptibility of the diabetic erythrocytes to oxidation injury was also shown to increase in the oxidation induced by t-BOOH (p < .05). Linear regression studies showed that TRAP was associated directly with uric acid (p < .05) and inversely with fructosamine and with glucose (p < .03 and p < .05 respectively) in patients with NIDDM, but not in the controls. The levels of fructosamine were found to be related to the basal damage of the red blood cells (direct correlation, p < .001). This study suggest an useful approach to diabetic oxidative stress for clinical settings.

Adult↗
PubMed1998

Iatrogenic mammary arteriovenous fistula caused by sternal wire.

Internal mammary arteriovenous fistulas are a rare complication of sternotomy. We present a case of a 64-year-old woman with a poststernotomy fistula between the left mammary vein and artery with formation of a pseudoaneurysm with subcutaneous extension. We describe the different imaging techniques that led to the diagnosis and the resolution of the fistula via endovascular embolization.

Arteriovenous Fistula↗
PubMed1998

Generalized background qEEG abnormalities in localized symptomatic epilepsy.

Spectral features of EEG background activity were studied in patients with localized symptomatic epilepsy (LSE), with origin in the frontal or temporal lobes. Z-values of high resolution spectra and measures of the parametric (xi alpha) model of the EEG were obtained for all 10/20 System leads and were compared with those obtained in a control group. Comparisons were performed between syndromic variants of LSE and between subgroups of patients with or without paroxysmal activity in their digital EEGs (dEEG). Marked reduction of the energy in the alpha range and a mild increase in the theta range were found in the patients, unrelated to the syndromic variant of the epilepsy. These deviations from normality were widespread on the scalp and were not related to antiepileptic medication. Non-parametric testing showed a positive correlation between the magnitude of the quantitative EEG abnormalities and the amount of paroxysmal activity in the dEEG. Slowing of the mean frequency of alpha components of the spectra, an actual decrease of power in the alpha range and an increase in the theta range explained the results. The most striking finding of this paper is that focal epileptogenesis may have a generalized impact in the frequency composition of EEG.

Adolescent↗
PubMed1998

Severe community-acquired pneumonia. Assessment of severity criteria.

The purpose of the study was to validate the criteria used in the guidelines of the American Thoracic Society (ATS) for severe community-acquired pneumonia (CAP). Severe pneumonia was defined as admission to the intensive care unit (ICU). Overall 331 nonsevere (84%) and 64 severe cases (16%) of CAP were prospectively studied. Mortality was 19 of 395 (5%) and 19 of 64 (30%), respectively. Single severity criteria as well as the ATS definition of severe pneumonia were assessed calculating the operative indices. A modified prediction rule including minor (baseline) and major (baseline or evolutionary) criteria was derived. Single minor criteria at admission had a low sensitivity and positive predictive value. Defining severe pneumonia according to the ATS guidelines had a high sensitivity (98%). However, specificity and positive predictive value were low (32% and 24%, respectively). A modified prediction rule (presence of two or three minor criteria [systolic blood pressure < 90 mm Hg, multilobar involvement, PaO2/FIO2 < 250] or one of two major criteria [requirement of mechanical ventilation, presence of septic shock]) had a sensitivity of 78%, a specificity of 94%, a positive predictive value of 75%, and a negative predictive value of 95%. The ATS definition of severe pneumonia was highly sensitive but insufficiently specific and had a low positive predictive value. Our suggested modified rule had a more balanced performance and, if validated in an independent population, may represent a more accurate definition of severe CAP.

APACHE↗
PubMed1998

Semaphorins III and IV repel hippocampal axons via two distinct receptors.

The semaphorins are the largest family of repulsive axon guidance molecules. Secreted semaphorins bind neuropilin receptors and repel sensory, sympathetic and motor axons. Here we show that CA1, CA3 and dentate gyrus axons from E15-E17 mouse embryo explants are selectively repelled by entorhinal cortex and neocortex. The secreted semaphorins Sema III and Sema IV and their receptors Neuropilin-1 and -2 are expressed in the hippocampal formation during appropriate stages. Sema III and Sema IV strongly repel CA1, CA3 and dentate gyrus axons; entorhinal axons are only repelled by Sema III. An antibody against Neuropilin-1 blocks the repulsive action of Sema III and the entorhinal cortex, but has no effect on Sema IV-induced repulsion. Thus, chemorepulsion plays a role in axon guidance in the hippocampus, secreted semaphorins are likely to be responsible for this action, and the same axons can be repelled by two distinct semaphorins via two different receptors.

Animals↗
PubMed1998

[Adherence of Acinetobacter baumannii to rat tracheal tissue].

BACKGROUND: Acinetobacter baumannii is an important nosocomial pathogen whose virulence factors have not been fully elucidated. AIM: To study the adherence and hemagglutinating capacity of several biotypes of Acinetobacter baumannii. MATERIAL AND METHODS: Thirty nine strains of Acinetobacter baumannii isolated from hospitalized patients were studied. The adherence of these strains to small pieces of rat tracheal tissue was studied. Additionally, their ability to hemagglutinate human erythrocytes and the effect of D-mannose and D-galactose on the adherence and hemagglutinating capacity was assessed. Transmission electron microscopy of strains was performed looking for the presence of fimbriae. RESULTS: All strains exhibited adherence to tissues. All strains had also D-mannose and D-galactose resistant hemagglutinating ability. Fimbriae were found in Acinetobacter baumannii and E coil cells. CONCLUSIONS: Adherence of Acinetobacter baumannii to rat tracheal tissue, apparently not related to the presence of fimbriae, may be a virulence mechanism of this bacterium.

Acinetobacter↗
PubMed1998

Rising incidence of non-Hodgkin's lymphoma in Spain: analysis of period of diagnosis and cohort effects.

Incidence trends in non-Hodgkin's lymphomas for the period 1973-1991 were studied using data from Spain's Zaragoza and Navarre registries. The overall rate of increase was 5.8% per year. Age-period-cohort models were used, also including sex and registry as explanatory variables. In these models, the variable period was categorized according to the observed changes in diagnostic availability during the length of the study. Non-Hodgkin's lymphomas increased with age, and rates were 31% lower in women. Incidence was almost 50% higher in Navarre, but differences in registry procedures might account for this discrepancy. The rise affects all adult age groups and seems to be the result of changes related not only to the period of diagnosis, mainly ascribable to improvements in diagnostic and coding practices, but also to the birth cohort. According to the model, the risk increased with on-coming generations at a rate of 1.5% per year. The AIDS epidemic in Spain is unable to explain this trend, although it may well exert a stronger influence in the future. Additional knowledge is required to understand the observed rise and to prevent the growing numbers of cases that are expected in years to come.

Adult↗
PubMed1998

[Reoperations of myocardial revascularization].

UNLABELLED: Coronary by-pass grafting is a well established procedure for ameliorating ischemic coronary disease. From time to time it is necessary to re-operate these patients. The objective of our paper is to present our experience in this field. Retrospective analysis of 128 patients operated on between February 1978 and November 1996, has been analyzed. The mean age was 57.4 +/- 0.7 years. 77.2 +/- 5 months elapsed between operations. Stable angina (20.4%) or unstable angina (76.3%), myocardial infarction (48%) and congestive heart failure (17%) were the predominant clinical manifestations. RESULTS: Hospital mortality was 10.9% (14 patients) and in the follow-up there were 16 deaths (14%). Perioperative myocardial infarction was the main cause of in-hospital mortality. In the follow-up there were 4 deaths due to myocardial infarction and another 4 patients died from neoplasms. Perioperative myocardial infarction was present in 9.3% (12 patients) IN CONCLUSION: a) Re-do coronary by-pass grafting is still a good procedure for solving myocardial ischemia in spite of a higher mortality and morbidity than in the original operation. b) There is no progression in the number of patients according to our experience, probably due to better techniques and the frequent actions by an intervention cardiologist. c) The long-term results are good enough, but with a higher mortality.

Adult↗
PubMed1998

[Treatment of pneumonia caused by Legionella with azithromycin].

Nineteen patients with pneumonia caused by Legionella, who did not need to be admitted to ICU were treated with 500 mg/day of azithromycin. The etiological diagnosis was made retrospectively by detecting Legionella pneumophila in the urine of nine patients and/or by serology (seroconversion or single titer 1/256) in 19 cases. None of them met the criteria for ICU admittance nor had received prior treatment with antibiotics which were potentially active against L. pneumophila. Serology tests and radiography of the thorax were carried out on all the patients in the study during their convalescence period. The average age (+/- SD) of the group was 58.5 +/- 16.2 years. The average respiratory frequency (+/- SD) 26 +/- 6 breaths per minute; the radiologic extension was of one lobule in 18 cases and two lobules in one case. No patients showed bilateral disease. Arterial gasometry (FiO2 0.21) showed a pO2 average of (+/- SD) 53 +/- 14 mmHg and the hemogram an average of 6.700 leukocytes/mm3 (range: 4,200-41-800). All the patients progressed favorably. The average duration of fever was 1.8 days; the average stay (+/- SD) was 6.1 +/- 2 days. The treatment was well tolerated. One month after discharge radiographies were clear for all patients. There were no relapses. In conclusion, 3-day administration of azithromycin was found to be a useful guide in the treatment of community acquired pneumonia caused by Legionella in patients whose clinical situation does not require ICU administration and allows for oral administration.

Adult↗
PubMed1998

[Placental histopathology in premature rupture of membranes. Its relationship with microbiological findings, maternal, and neonatal outcome].

BACKGROUND: There is a close relationship between premature membrane rupture, bacterial infections and premature labor. AIM: To study placental histological changes in patients with preterm membrane rupture. To establish a relationship between pathological findings, amniotic fluid and lower genital tract microbiological studies, maternal and neonatal outcome. PATIENTS AND METHODS: Patients with premature membrane rupture of membranes between 24 and 34 weeks of gestation participated in this study. On admission, patients had no evidence of clinical chorioamnionitis, labor or fetal distress. Microbiological studies of the amniotic fluid and cervicovaginal secretions were performed and the placenta was sent for pathological study. RESULTS: Seventy one placentas were available for the study. The main pathological findings were acute chorioamnionitis in 58%, trophoblastic proliferation in 38%, funisitis in 37%, villitis in 16%, fetal vascular lesions in 14% and no findings in 17%. Microbial invasion of amniotic cavity was present in 89% of acute chorioamnionitis. Sixty one percent of trophoblastic proliferation and all fetal vascular lesions were associated with negative amniotic and cervical cultures. Newborns with acute funisitis had a higher frequency of neonatal death (29%), severe asphyxia (42%) and neonatal infections (29%). CONCLUSIONS: Acute chorioamnionitis is the most frequent finding in patients with preterm membrane rupture and microbial invasion of amniotic cavity. In the absence of intra amniotic infection, proliferation of the trophoblast and the presence of fetal vascular lesions predominate. Acute funisitis is strongly associated with adverse fetal outcome.

Amniotic Fluid↗
PubMed1998

Adherence of Acinetobacter baumannii to rat bladder tissue.

Acinetobacter baumannii, an important nosocomial pathogen, causes severe infections in patients of intensive care units, but its pathogenic attributes are unknown. Previously, the adherence of A. baumannii to cell lines has been negative in the authors' laboratory. In this work, the adherence of strains of A. baumannii of various biotypes to small pieces of rat bladder tissue was investigated. Tissue pieces were submerged into cultures of A. baumannii and sessile cells were counted after removing planktonic bacteria. Fimbriae and sessile cells were examined by transmission and scanning electron microscopy, respectively. In contrast to a uropathogenic strain of Escherichia coli, all cultures exhibited a mannose- and galactose-resistant agglutination of human group O red blood cells as well as mannose- and galactose-resistant adherence to the bladder tissue. Inhibition of exopolysaccharide synthesis did not modify adherence. Indeed, adherence, apparently unrelated to these fimbriae or to the exopolysaccharide, may be a factor contributing to the pathogenicity of A. baumannii in the urinary tract or in other tissues.

Acinetobacter↗