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Biomedical subjects

J López

Publications and source records attributed to J López.

At least 19 recordsLinked to original sources
PubMed2006

Variable very-high-energy gamma-ray emission from the microquasar LS I +61 303.

Microquasars are binary star systems with relativistic radio-emitting jets. They are potential sources of cosmic rays and can be used to elucidate the physics of relativistic jets. We report the detection of variable gamma-ray emission above 100 gigaelectron volts from the microquasar LS I 61 + 303. Six orbital cycles were recorded. Several detections occur at a similar orbital phase, which suggests that the emission is periodic. The strongest gamma-ray emission is not observed when the two stars are closest to one another, implying a strong orbital modulation of the emission or absorption processes.

Journal Article↗
PubMed2006

Donor age and degree of HLA matching have a major impact on the outcome of unrelated donor haematopoietic cell transplantation for chronic myeloid leukaemia.

We analysed the outcome of 92 consecutive unrelated donor haematopoietic cell transplantations (UD-HCTs) performed in Spain to treat adult patients with CML in the first chronic phase (1CP). Patients' and donors' median age was 32 (15-49) and 36 (22-56) years, respectively. In all, 73 pairs (79%) matched for A, B+/-C and DRB1+/-DQB1 loci and 19 had > or =1 mismatch. Their probability of survival and disease-free survival at 4 years were 50 and 46%, respectively. Pretransplant factors associated with a better survival were patient age <25 years (P=0.035), donor age < or =36 years (P=0.012), use of cyclosporine since day -7 (P=0.001), and matching 8/8, 9/10 or 10/10 loci at allele level (P=0.003). In multivariate analysis only donor age (P=0.003; RR=3.1 (95% CI: 1.3-7.1)) and degree of HLA-matching (P=0.009; RR: 7.7 (95% CI: 1.8-33)) maintained their significance. The addition of these two variables to the EBMT prognostic score allowed an adequate risk assessment for patients receiving a UD-HCT during 1CP. Our analysis shows that in patients with a young and fully allele-matched donor, UD-HCT should be considered in the initial therapeutic algorithm due to its excellent outcome (92% survival at 2 years).

Adolescent↗
PubMed2006

[Solitary costal plasmacytoma: a rare cause of subacute demyelinating polyradiculoneuropathy].

INTRODUCTION: The solitary plasmacytoma (SP) is a non-frequent, localized variant of multiple myeloma with a single bone lesion and earlier appearance. Polyradiculoneuropathy is the most frequent neurological manifestation. We report the case of a young male who developed a subacute demyelinating polyradiculoneuropathy as the initial symptomatology of a costal SP, which constitutes an extremely infrequent association, given age and site of the lesion. CASE REPORT: A 32-year old, previously healthy, man presented with a one month history of progressive symmetrical paraparesis and paresthesias in feet. The neurological examination revealed 4/5 paraparesis, global arreflexia and hypopalesthesia in legs. Cerebrospinal fluid examination revealed elevated proteins (83 mg/dl) with normal cell count and glucose content. Investigations showed high levels of beta(2)-microglobulin (3 mg/l), and a monoclonal IgG lambda gammapathy. The chest X-ray and thoracic CT revealed an osteolytic lesion in the left third rib. Nerve conduction studies showed sensitive and motor polyneuropathy with secondary axonal degeneration. Bone marrow biopsy was normal. Second and third left ribs were excised, revealing a pathologic diagnosis of plasmacytoma. The patient became asymptomatic after corticosteriod administration lesion excision and local radiotherapy. Conclusions. Subacute demyelinating polyradiculoneuropathy can be due to multiple causes. SP can be one of its etiologies and occur at infrequent ages and localizations.

Adult↗
PubMed2005

Body mass index has a greater impact on pregnancy outcomes than gestational hyperglycaemia.

AIMS/HYPOTHESIS: We evaluated diabetes-related pregnancy outcomes in a cohort of Spanish women in relation to their glucose tolerance status, prepregnancy BMI and other predictive variables. METHODS: The present paper is part of a prospective study to evaluate the impact of American Diabetes Association (2000) criteria in the Spanish population. A total of 9,270 pregnant women were studied and categorised as follows according to prepregnancy BMI quartiles and glucose tolerance status: (1) negative screenees; (2) false-positive screenees; (3) gestational diabetes mellitus (GDM) according to American Diabetes Association criteria only; and (4) GDM according to National Diabetes Data Group criteria (NDDG). We evaluated fetal macrosomia, Caesarean section and seven secondary outcomes as diabetes-related pregnancy outcomes. The population-attributable and population-prevented fractions of predictor variables were calculated after binary logistic regression analysis with multiple predictors. RESULTS: Both prepregnancy BMI and abnormal glucose tolerance categories were independent predictors of pregnancy outcomes. The upper quartile of BMI accounted for 23% of macrosomia, 9.4% of Caesarean section, 50% of pregnancy-induced hypertension and 17.6% of large-for-gestational-age newborns. In contrast, NDDG GDM accounted for 3.8% of macrosomia, 9.1% of pregnancy-induced hypertension and 3.4% of preterm births. CONCLUSIONS/INTERPRETATION: In terms of population impact, prepregnancy maternal BMI exhibits a much stronger influence than abnormal blood glucose tolerance on macrosomia, Caesarean section, pregnancy-induced hypertension and large-for-gestational-age newborns.

Adult↗
PubMed2005

Modelling the extra and intracellular uptake and discharge of heavy metals in Fontinalis antipyretica transplanted along a heavy metal and pH contamination gradient.

Samples of the aquatic bryophyte Fontinalis antipyretica Hedw. were transplanted to different sites with the aim of characterizing the kinetics of the uptake and discharge of heavy metals in the extra and intracellular compartments. The accumulation of metals in extracellular compartments, characterized by an initial rapid accumulation, then a gradual slowing down over time, fitted perfectly to a Michaelis-Menten model. The discharge of metals from the same compartment followed an inverse linear model or an inverse Michaelis-Menten model, depending on the metal. In intracellular sites both uptake and discharge occurred more slowly and progressively, following a linear model. We also observed that the acidity of the environment greatly affected metal accumulation in extracellular sites, even when the metals were present at relatively high concentrations, whereas the uptake of metals within cells was much less affected by pH.

Aluminum↗
PubMed2005

Potential impact of American Diabetes Association (2000) criteria for diagnosis of gestational diabetes mellitus in Spain.

AIMS/HYPOTHESIS: This study was carried out to determine the impact of American Diabetes Association (ADA) 2000 criteria for the diagnosis of gestational diabetes mellitus (GDM) in the Spanish population. METHODS: Pregnant women were assigned to one of four categories: negative screenees, false-positive screenees, ADA-only-GDM (untreated) and GDM according to National Diabetes Data Group (NDDG) criteria (treated). Fetal macrosomia and Caesarean section were defined as primary outcomes, with seven additional secondary outcomes. RESULTS: Of 9,270 pregnant women screened for GDM, 819 (8.8%) met NDDG criteria. If the threshold for defining GDM had been lowered to ADA criteria, an additional 2.8% of women would have been defined as having the condition (relative increase of 31.8%). Maternal characteristics of women with ADA-only-GDM were between those of false-positive screenees and women with NDDG-GDM. The risk of diabetes-associated complications was slightly elevated in the individuals who would have been classified as abnormal only after the adoption of ADA criteria. In addition, the ADA-only-GDM contribution to morbidity was lower than that of other variables, especially BMI. CONCLUSIONS/INTERPRETATION: Use of the ADA criteria to identify GDM would result in a 31.8% increase in prevalence compared with NDDG criteria. However, as the contribution of these additionally diagnosed cases to adverse GDM outcomes is not substantial, a change in diagnostic criteria is not warranted in our setting.

Adolescent↗
PubMed2005

Effect of C content on the mechanical properties of solution treated as-cast ASTM F-75 alloys.

The mechanical properties of solution treated ASTM F-75 alloys with various carbon contents have been studied. Alloys cast under the same conditions were subjected to solution treatment for several periods and then their tensile properties were evaluated. In the as-cast conditions, the alloys exhibited higher strength values with increasing carbon content whereas their ductility was not significantly affected. For the solution treated alloys, the variation of the strength was characterized by a progressive increase for short treatment times until a maximum value was achieved, which was followed by a diminution in this property for longer treatment times. This behavior was more accentuated for the case of the alloys with medium carbon contents, which also exhibited the highest values of strength. Furthermore, the alloy's ductility was enhanced progressively with increasing solution treatment time. This improvement in ductility was significantly higher for the medium carbon alloys compared with the rest of the studied alloys. Thus, high and low carbon contents in solution treated ASTM F-75 alloys did not produced sufficiently high tensile properties.

Alloys↗
PubMed2005

High-strength apatitic cement by modification with superplasticizers.

This study reports on a novel method to improve the strength of apatitic bone cements. The liquid phase of Biocement-H was modified with commercial superplasticizers. The results showed that small additions, i.e. 0.5 vol%, in the aqueous liquid phase improved the maximum compressive strength of Biocement-H (35 MPa) by 71%, i.e. 60 MPa. Moreover, the addition of high amounts of superplasticizers, i.e. 50 vol.%, allowed for a significant reduction of the liquid-to-powder ratio from 0.32 to 0.256 mL/g, without affecting the maximum strength and/or the workability of the cement. These results open up new ways to develop injectable and high-strength apatitic bone cements for load-bearing applications.

Bone Cements↗
PubMed2005

[Advantages and characteristics of the laparoscopic approach in the elderly].

Both the age of the population and anesthetic and surgical techniques are advancing. Currently, 40% of surgical activity is performed in patients older than 65 years, who present a higher surgical risk than younger patients. The aim of treatment in the elderly is to provide the best possible quality of life, even though this represents a surgical challenge because of associated comorbidity and reduced cardiopulmonary reserve. From the moment at which laparotomy becomes an increased stress in the elderly, laparoscopic surgery can be particularly advantageous in this population. Therefore, minimally invasive surgery may have a greater impact in these individuals than in younger patients in reducing postoperative pain, cardiorespiratory complications, hospital stay, and recovery time before resuming physical activity. The recent advances in anesthesia, together with improved patient selection and perioperative cardiac care, and the general adoption of minimally invasive access have enabled more complex gastrointestinal procedures to be performed in the elderly. The factors that could influence the development of this type of approach in the elderly, as well as the precautions that should be taken, should be further analyzed.

Aged↗
PubMed2005

Clinical characterization of breakthrough bacteraemia: a survey of 392 episodes.

BACKGROUND: Few data are available on the clinical features of patients who develop breakthrough bacteraemia, understood as positive blood cultures despite appropriate antibiotic therapy. OBJECTIVES: To determine the clinical significance and outcome of a large series of breakthrough bacteraemia. DESIGN: Retrospective analysis of a prospectively collected database. SETTING: Two university-affiliated hospitals in Catalonia, Spain. SUBJECTS: A total of 392 individuals who suffered an episode of breakthrough bacteraemia recorded between 1997 and 2002. INTERVENTIONS: Demographic characteristics, underlying diseases, origin of infection, sources of infection, microorganisms isolated, McCabe and Jackson prognostic criteria, and mortality were analysed. RESULTS: Breakthrough bacteraemia was detected in 392 of 6324 (6.1%) episodes of bacteraemia. Eighty per cent of episodes were nosocomial. The most frequent source of infection in breakthrough bacteraemia was endovascular (70%). Coagulase-negative staphylococci, Staphylococcus aureus, and Pseudomonas aeruginosa were the most significant microorganisms involved. Nosocomial acquisition together with selected sources (central venous catheter, endocarditis and other endovascular foci), underlying conditions (neutropenia, polytraumatism, allogenic bone marrow and kidney transplantation), and particular microbial aetiologies (S. aureus, P. aeruginosa and polymicrobial) were independently associated with increased risk for developing breakthrough bacteraemia. Crude mortality rate was greater in patients with breakthrough bacteraemia (16% vs. 12.3%; P<0.05), and this condition was an independent predictor of death (OR 1.4, 95% CI, 1-1.9; P=0.04). CONCLUSIONS: In view of a case of breakthrough bacteraemia it is mandatory to search for an endovascular focus. Empiric treatment should be directed to cover S. aureus, coagulase-negative staphylococci and nonfermentative Gram-negative bacilli. Breakthrough bacteraemia is an independent predictor of death.

Anti-Bacterial Agents↗
PubMed2004

[Evolution study in children with suspected obstructive sleep apnea].

INTRODUCTION: Obstructive sleep apnea syndrome is a common disorder in childhood with an uncertain evolution. OBJECTIVES: Study of children's clinical evolution with suspected diagnosis of OSAS, which was carried out after two years of an overnight polisomnogram. PATIENTS AND METHODS: 73 children were studied. We evaluated if they had been operated and what type of surgery was performed, Brouillete Scale and subjective impressions. We have correlated: age, clinical evolution and surgery. RESULTS: Age was inversely correlated with changes in Brouillete (r=-0.39, p=0.002), standing out that children that underwent surgery were younger (4.1 vs. 7.0 years, Student t: -4.22, p=0.00009). Without the influence of age, the difference between evolution in operated and not operated ones was not significative, statistically speaking, but it was if we analysed the different types of surgery by themselves (Snedecor F: 3.9, p=0.007), tonsillectomy was the larger. CONCLUSION: The middle-term evolution in children with OSAS is good if we use the correct treatment.

Adenoidectomy↗
PubMed2004

Percutaneous tracheostomy: Ciaglia Blue Rhino versus Griggs' Guide Wire Dilating Forceps. A prospective randomized trial.

BACKGROUND: Percutaneous tracheostomy (PT) has gained widespread acceptance to control the airway in patients requiring prolonged mechanical ventilation. Since 1985, new techniques for PT have been described. It was the aim of this investigation to compare two different PT techniques: the Ciaglia Blue Rhino (CBR) and the Guide Wire Dilating Forceps (GWDF). METHODS: A prospective randomized trial was performed in four intensive care units. After informed consent, 53 consecutive patients were randomized to undergo CBR or GWDF. Procedural complications were evaluated and specific symptoms of the upper airway tract in survivors were assessed. RESULTS: Twenty-seven patients were randomly assigned to CBR and 26 to GWDF. Patients mean ages were 62.7 +/- 15.8 years and 62.2 +/- 18.3, respectively. Mean APACHE II scores were 20.6 +/- 6.8 and 21.2 +/- 7.2, respectively. Median duration of the procedure was 7 min (range: 4-17 min) with GWDF and 9 min (range: 5-32 min) with CBR (P = 0.16). Seven patients in the group undergoing GWDF had complications (desaturation: two; mild bleeding: one; infected stoma: one; inability to complete the procedure: three). Two patients had complications in the group undergoing CBR (mild bleeding) (P = 0.07). Survivors were followed up after discharge. Three patients (all of them having undergone GWDF) were symptomatic (two with mild hoarseness and one with a persistent foreign body sensation), but laryngotracheoscopy was negative. CONCLUSIONS: Our results show no differences between both techniques regarding surgical duration or procedural complications. Late symptoms were encountered in three patients undergoing GWDF, however, laryngotracheoscopy failed to document anatomical or functional abnormalities.

Chi-Square Distribution↗
PubMed2003

The role of Doppler studies in predicting individual intrauterine fetal demise after laser therapy for twin-twin transfusion syndrome.

OBJECTIVE: To investigate the role of Doppler studies in predicting individual fetal demise in patients scheduled for selective laser photocoagulation of communicating vessels (SLPCV) for twin-twin transfusion syndrome (TTTS). METHODS: Doppler studies of the umbilical artery, umbilical vein, ductus venosus, tricuspid valve regurgitation and middle cerebral artery were performed in the donor and recipient twins before and 24 hours after SLPCV. Results were analyzed cross-sectionally and longitudinally. As multiple comparisons were made, an a priori alpha rejection was set at P < 0.001. RESULTS: One hundred and ten consecutive patients were available for analysis. Overall fetal survival was 68.6% (151/220) with at least one survivor in 88.2% (97/110) of cases. Absent or reversed end-diastolic velocity in the umbilical artery of the donor twin was the only preoperative Doppler result predictive of intrauterine fetal demise (IUFD) (10/15, 66.7%, P < 0.001). Postoperatively, reversed flow during atrial contraction in the ductus venosus of the donor twin showed a trend towards prediction of IUFD of this fetus (4/5, 80%, P = 0.007). No other Doppler studies, including the longitudinal analyses, were predictive of IUFD. CONCLUSIONS: Our data suggest that preoperative absent or reversed end-diastolic velocity in the umbilical artery may be useful in predicting individual fetal demise of the donor twin in TTTS patients scheduled for SLPCV. This may reflect the role of decreased individual placental mass that may be associated with some donor twins. The inability of other Doppler studies to predict individual IUFD may be explained preoperatively by the effect of the interfetal vascular connections on the individual Doppler signals and postoperatively by the effect of surgery or the timing of the assessment. Our findings may be important in patient counseling, in furthering understanding of the disease, and perhaps in improving surgical technique.

Cross-Sectional Studies↗
PubMed2002

Delayed acute capture myopathy in three roe deer.

Delayed acute capture myopathy is the term used to describe the clinical syndrome observed in three roe deer captured by drive-nets and transported to an enclosure for scientific purposes. The animals died 48 h, 60 h and 8 days after being captured. The simultaneous deaths coincided with a previous episode of deliberate human disturbance. The histopathological findings were indicative of acute myopathy and myoglobinaemic nephrosis. These could be related to an ataxic myoglobinuric syndrome brought on by capture and transport operations. The lack of clinical signs and negative prognosis indicators in the period between capture and just before death. the absence of gross muscular lesions in the animal that died after 8 days post-capture, the simultaneous deaths of animals captured at different times and the evidence of deliberate human disturbance in the enclosure are suggestive of death triggered by a second stress episode.

Acute Disease↗
PubMed2002

Critical steps in the early evolution of the isocortex: insights from developmental biology.

This article proposes a comprehensive view of the origin of the mammalian brain. We discuss i) from which region in the brain of a reptilian-like ancestor did the isocortex originate, and ii) the origin of the multilayered structure of the isocortex from a simple-layered structure like that observed in the cortex of present-day reptiles. Regarding question i there have been two alternative hypotheses, one suggesting that most or all the isocortex originated from the dorsal pallium, and the other suggesting that part of the isocortex originated from a ventral pallial component. The latter implies that a massive tangential migration of cells from the ventral pallium to the dorsal pallium takes place in isocortical development, something that has not been shown. Question ii refers to the origin of the six-layered isocortex from a primitive three-layered cortex. It is argued that the superficial isocortical layers can be considered to be an evolutionary acquisition of the mammalian brain, since no equivalent structures can be found in the reptilian brain. Furthermore, a characteristic of the isocortex is that it develops according to an inside-out neurogenetic gradient, in which late-produced cells migrate past layers of early-produced cells. It is proposed that the inside-out neurogenetic gradient was partly achieved by the activation of a signaling pathway associated with the Cdk5 kinase and its activator p35, while an extracellular protein called reelin (secreted in the marginal zone during development) may have prevented migrating cells from penetrating into the developing marginal zone (future layer I).

Animals↗
PubMed2001

Elimination of cutting oil wastes by promoted hydrothermal oxidation.

Cutting oils are emulsionable fluids widely used in metalworking processes. Their composition is normally oil, water, and additives (fatty acids, surfactants, biocides, etc.) generating a toxic waste after a long use. Generally, it is a waste too dilute to be incinerated and it is difficult to treat biologically. Other conventional treatment methods currently used are not satisfactory from the environmental point of view. Wet air oxidation (WAO) and supercritical water oxidation (SCWO) are two forms of hydrothermal oxidation that have been proved to be effective processes to treat a wide variety of industrial wastes, but hardly tested for oily wastes. In the case of refractory wastes, WAO process is not efficient enough due to the moderate temperatures used. SCWO is a more powerful process since operating temperatures are usually around 600 degrees C, but the use of severe conditions leads to major disadvantages in the commercialization of the technology. In order to enhance WAO and SCWO efficiency at mild conditions, the use of free radical promoters has been studied in this work. Both normal and promoted hydrothermal oxidation have been tested to treat cutting oil wastes in a continuous flow system operating at 300-500 degrees C. Hydrogen peroxide has been used both as a source of oxygen and as a source of free radicals by introducing it into the reactor with or without previous thermal decomposition, respectively. Organic material is easily oxidized in both cases, obtaining more than 90% TOC reduction in less than 10s at 500 degrees C. At lower temperatures, the use of promoters clearly enhances the oxidation process. Activation energies have been estimated for normal and promoted oxidation processes.

Environmental Pollution↗