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Biomedical subjects

J Sanz

Publications and source records attributed to J Sanz.

At least 37 records · Page 2Linked to original sources
PubMed2005

Influence of vacancy ordering on the percolative behavior of (Li(1)(-x)Na(x))(3y)La(2/3-y)TiO(3) perovskites.

Influence of the vacancy concentration on the Li conductivity of the (Li(1-x)Na(x))(0.2)La(0.6)TiO(3) and (Li(1-x)Na(x)(0.5)La(0.5)TiO(3) perovskite series, with 0 < or = x < 1, has been investigated by neutron diffraction (ND), impedance spectroscopy (IS), nuclear magnetic resonance (NMR), and Monte Carlo simulations. In both series, Li(+) ions occupy unit cell faces, but Na(+) ions are located at A sites of the perovskite. From this fact, the amount of vacant A sites that participate in Li conductivity is given by the expression n(v) = [Li] + square, where square is the nominal vacancy concentration. Substitution of Li by Na decreases the amount of vacancies, reducing drastically the Li conductivity when n(v) approaches the percolation threshold of the perovskite conduction network. In disordered (Li(1-x)Na(x))(0.5)La(0.5)TiO(3) perovskites, the percolation threshold is 0.31; however, in ordered (Li(1-x)Na(x))(0.2)La(0.6)TiO(3) perovskites, this parameter changes to 0.26. Near the percolation threshold, the amount of mobile Li species deduced by (7)Li NMR spectroscopy is lower than that derived from structural formulas but higher than deduced from dc conductivity measurements. Conductivity values have been explained by Monte Carlo simulations, which assume a random walk for Li ions in the conduction network of the perovskite. In these simulations, distribution of vacancies conforms to structural models deduced from ND experiments.

Journal Article↗
PubMed2005

A randomized controlled trial investigating the efficacy and safety of switching from a protease inhibitor to nevirapine in patients with undetectable viral load.

OBJECTIVE: To assess the antiviral efficacy and safety of switching from a protease inhibitor (PI) to nevirapine in patients with long-term HIV-1 RNA suppression on PI-containing regimens, and to assess its influence in the adherence to treatment. METHODS: In an open-label multicentre study, 160 HIV-infected patients with undetectable viral load for at least 6 months on a PI-containing regimen were randomized to either continue with their PI regimen (n=79) or replace PI with nevirapine (n=81). Clinical assessment included plasma HIV-1 RNA, blood chemistry, haematology, lymphocyte counts and adverse events reports. Adherence to treatment and lipodystrophy syndrome were assessed by patient self-reporting. RESULTS: Treatment efficacy was equivalent in the two arms, for patients with viral loads either above or below 100 000 HIV-1 RNA copies/mL. The increase in CD4 cell count was significant in both arms (P<0.00001) but the average CD4 cell count at 48 weeks was slightly higher in the nevirapine arm (596 vs. 569; P=0.1588). The number of patients with severe hypertriglyceridaemia (>400 mg/dL) after 48 weeks of treatment decreased in the nevirapine arm (from 11 to six), but increased in the PI arm (from four to 11) and led to treatment discontinuation in two patients. Lipodystrophy changes increased in 15% of patients in the PI arm but decreased in 4% of patients in the nevirapine arm. Finally, although adherence was similar in the two arms, patients reported that it required significantly less effort to stay on treatment in the nevirapine arm. Conclusions The results indicate that switching from PI to nevirapine is as effective as continuing with PI for maintaining viral control, even in patients with baseline viral load above 100,000 copies/mL. In addition, reductions in hypertriglyceridaemia and lipodystrophy and in the effort required to stay on treatment were observed.

Adult↗
PubMed2005

[Fibromyalgia and its diagnosis].

Fibromyalgia or fibromyalgic syndrome (FMS) is a clinical picture of unknown origin that is characterized by generalized, incapacitating and chronic pain together with the demonstration in the physical examination of previously defined points in which moderate pressure causes pain, called fibromyalgia tender points (FTP). FMS lacks objective, analytic imaging or pathological data, so that its diagnosis is based exclusively on subjective data, such as that the pain reported by the patient and the pain caused by the FTP pressure. Although the fibromyalgia classification criteria of the American College of Rheumatology are not diagnostic criteria, they have been extensively used to diagnose FMS in patients with chronic diffuse arthromyalgias. Fibromyalgia diagnosis reduces the patient's anxiety, avoiding complementary expensive and unnecessary tests and it allows the patient to share his/her fears, illnesses and expectations with other human beings who suffer the same problem.

Diagnosis, Differential↗
PubMed2005

Hypofrontality in men with first-episode psychosis.

BACKGROUND: Decreased metabolic activity in the prefrontal cortex during cognitive activation is a recurrent finding and a likely functional marker of schizophrenia. AIMS: To investigate the occurrence of hypofrontality in patients with first-episode psychosis, with or without evolution to schizophrenia. METHOD: We used fluorodeoxyglucose positron emission tomography during the performance of an attention task and magnetic resonance imaging to study the dorsolateral prefrontal region in 13 men with a first episode of psychosis. Data from patients who progressed to schizophrenia were compared with those of patients who did not meet criteria for this diagnosis after 2 years. RESULTS: Patients who developed schizophrenia demonstrated a significant hypofrontality in the dorsolateral prefrontal cortex in comparison with the non-schizophrenia and control groups. CONCLUSIONS: Our results suggest that hypofrontality could be a marker of schizophrenia at the time of the first psychotic episode, in agreement with neurodevelopmental theories of schizophrenia.

Adult↗
PubMed2004

Gas chromatographic-mass spectrometric method for the qualitative and quantitative determination of disaccharides and trisaccharides in honey.

An improved method has been developed to identify and quantify honey disaccharides and trisaccharides by gas chromatography and mass spectrometry. The procedure, based on mass spectral and retention data ("retention time windows") determined on two capillary columns with different stationary phases allowed the identification and quantitation in honey of 16 disaccharides and 9 trisaccharides, some of which were not previously identified by GC. The reliability of the analytical results was considerably improved by the use of this procedure: several unidentified disaccharides and trisaccharides were detected, and their presence was taken into account in the quantification.

Disaccharides↗
PubMed2004

Analysis of volatile components of Lavandula luisieri L. by direct thermal desorption-gas chromatography-mass spectrometry.

Volatile components of wild samples of Lavandula luisieri collected in Central and Southern Spain have been analyzed by direct thermal desorption coupled to gas chromatography-mass spectrometry (DTD-GC-MS). This method requires only 10-20 mg of dry sample, allowing to obtain qualitative and quantitative results from different plant parts such as flowers and leaves. Average volatile yield calculated from 51 individual plants was higher for leaves (9.7mg g(-1)) than for flowers (2.9mg g(-1)). Samples presented a high variation in their yield and composition. Major components were camphor and 1,8-cineole (up to 80.9 and 76.7% in leaves; 87.8 and 85.2% in flowers, respectively); however, these compounds were not detected in several samples. Other major component (up to 60% in flowers and leaves) was 2,3,5,5-tetramethyl-4-methylene-2-cyclopenten-1-one. Multivariate analysis was applied to quantitative data from nine selected compounds in order to show the presence of several patterns in plant composition which were only partially related to the site of collection.

Discriminant Analysis↗
PubMed2004

Growth response to ozone of annual species from Mediterranean pastures.

Ozone (O3) phytotoxicity has been reported on a wide range of plant species. However, scarce information has been provided regarding the sensitivity of semi-natural grassland species, especially those from dehesa Mediterranean grasslands, in spite of their great biological diversity and the high O3 levels recorded in the region. A screening study was carried out in open-top chambers (OTCs) to assess the O3-sensitivity of representative therophytes of these ecosystems based on the response of selected growth-related parameters. Three O3 treatments and 3 OTCs per treatment were used. Legume species were very sensitive to O3, because 78% of the tested species showed detrimental effects on their total biomass relative growth rate (RGR) following their exposure to O3. The Trifolium genus was particularly sensitive showing O3-induced adverse effects on most of the assessed parameters. Gramineae plants were less sensitive than Leguminosae species because detrimental effects on total biomass RGR were only observed in 14% of the assessed species. No relationship was found between relative growth rates when growing in clean air and O3 susceptibility. The implications of these effects on the performance of dehesa acidic grasslands and on the definition of ozone critical levels for the protection of semi-natural vegetation are discussed.

Air Pollutants↗
PubMed2004

[Recombinant activated factor VII used in a man with refractory bleeding from a stab wound injuring the liver and kidney].

A 30-year-old man bled massively from a stab wound that injured his liver and right kidney and entered a life-threatening cycle of transfusion, hypothermia, coagulopathy, and rebleeding in spite of surgery and aggressive resuscitation. He was given a single dose of recombinant activated factor VII (rVIIa; NovoSeven, Novo Nordisk, Denmark) in a final attempt to save his life. The patient responded favorably, as bleeding stopped almost immediately and coagulation markers became normal. Clinical course following rVIIa administration was good. Severe bleeding in the trauma patient needing massive transfusion can become complicated by dilutional coagulopathy and hypothermia. Therapy with rVIIa is a promising aid to controlling bleeding in the repeatedly transfused patient who does not respond to standard replacement of blood products.

Adult↗
PubMed2004

[BK virus in kidney allografts: a search for histologic evidence of the infection].

BACKGROUND: BK virus (BKV) associated interstitial nephritis is a complication in renal transplantation recipients. Its incidence is controversial. The aim of the present study is to determine the incidence of histopathologic evidence of BKV-infection in a single centre. MATERIALS AND METHODS: Renal allograft tissue samples (n = 838) from 526 patients undergoing renal transplant were evaluated by light microscopy. Polymerase chain reaction (PCR) assay for BKV DNA was performed in 41 microdissected cell populations from cases with viral inclusions, cases with other nuclear changes, and cases without nuclear changes. RESULTS: Polyomavirus-inclusions were identified in six cases (five with interstitial nephritis and other one with only urothelial infection). In one case with interstitial nephritis the DNA was degraded. PCR confirmed BKV infection in the other five and was negative in cases without inclusions. CONCLUSIONS: Five patterns of inclusions bodies are observed and they appear to be characteristic. PCR assay seemingly have a high specificity for BKV detection and it does not usually detect latent viral infection.

Adult↗
PubMed2003

Analysis by gas chromatography-mass spectrometry of the essential oil from the aerial parts of Pimpinella junoniae Ceb. & Ort., gathered in La Gomera, Canary Islands, Spain.

The essential oil from the aerial parts of Pimpinella junoniae Ceb. & Ort., growing in La Gomera, Canary Islands, Spain, was studied by gas chromatography and gas chromatography-mass spectrometry, and 43 constituents were identified. The major components were found to be alpha-zingiberene (20.6%), alpha-pinene (17.9%), (E)-beta-farnesene (9.3%), ar-curcumene (7.4%), beta-phellandrene (7.0%), beta-bisabolene (6.1%) and epoxypseudoisoeugenyl 2-methylbutyrate (6.0%). The decomposition product of epoxypseudoisoeugenol derivatives, 5-methoxy-2-methylbenzofuran (5.7%), moderate amounts of other arylpropanoids with the pseudoisoeugenol skeleton (total percentage, 5.2%) and other compounds such as beta-sesquiphellandrene (3.0%), cis-beta-guaiene (1.5%), alpha-phellandrene (1.5%) and alpha-bisabolol (1.3%), were also found.

Gas Chromatography-Mass Spectrometry↗
PubMed2003

Patterns in the precision of quantitative data from multicomponent gas chromatographic or gas chromatographic-mass spectrometric analysis.

The dispersion of the quantitative results in the analysis of volatile compounds from multicomponent mixtures by different fractionation techniques (solid-phase microextraction and direct thermal desorption) followed by GC or GC-MS presents nonrandom patterns related to the existence of different factors in the fractionation process or in the chromatographic separation which affect, to a different extent, the recovery of the sample components. Statistical techniques have been used to show the relative importance of these factors. The improvement in data precision achieved by using volatile compound concentration ratios is discussed.

Chromatography, Gas↗
PubMed2003

Cerebral metabolism and risperidone treatment in schizophrenia.

This paper compares the metabolic changes associated with risperidone treatment in schizophrenia to those induced by haloperidol, as a representative typical neuroleptic. A group of 11 schizophrenic patients of recent onset underwent two [18F] fluoro-desoxi-glucose (FDG)-positron emission tomography (PET) scans at rest: the first one at the moment of the diagnosis, after a minimal treatment with haloperidol followed by wash-out, and the second one after 6 months on risperidone. The study also included 34 patients on chronic haloperidol for comparison. PET images were analyzed using Statistical Parametric Mapping (SPM'99) methods. The only change after treatment with risperidone with respect to the baseline was a slight increase in activity in the primary visual area and the right insula. Patients on chronic haloperidol showed increased activity in the motor cortex and cerebellum, as compared to both minimally treated and risperidone-treated patients. The pattern of metabolic changes induced by risperidone appears to be different from that produced by typical antipsychotics.

Adult↗
PubMed2003

Analysis by gas chromatography-mass spectrometry of the essential oils from the aerial parts of Rutheopsis herbanica (Bolle) Hans. & Kunk., gathered in Fuerteventura (Canary Islands).

The essential oil from the aerial parts of Rutheopsis herbanica (Bolle) Hans. & Kunk., growing in Fuerteventura, Canary Islands, Spain, was studied by gas chromatography and gas chromatography-mass spectrometry, and 42 constituents were identified. The major components were found to be alpha-pinene (29.4%), dillapiole (21.3%), limonene (14.1%), beta-pinene (13.2%) and myristicin (10.0%). As far as we know, this is the first report on the essential oil composition of this species.

Apiaceae↗
PubMed2003

UV/H2O2 chemical oxidation for high loaded effluents: a degradation kinetic study of LAS surfactant wastewaters.

This paper describes a laboratory study conducted to elucidate the possibility of treating high loaded solutions of surfactants through an Advanced Oxidation Process. Synthetic solutions of linear alkylbenzene sulfonates are treated in this work as this is a model compound commonly used in the formulation of detergents, with a great presence in urban and industrial waste-waters. The application of UV combined with hydrogen peroxide to oxidise a surfactant effluent is shown to be suitable as a primary oxidation step since conversions of around 50% of the original compound are achieved in the most favourable cases. Initially, the influence of the operating variables on the degradation levels is analysed in this work. A kinetic model that takes into account both the contributions of direct photolysis and radical attack is also worked out. Direct photolysis is performed to determine the quantum yield in the single photodecomposition reaction. Additionally, the rate constant of the reaction between hydroxyl radicals and LAS in the oxidising system H2O2/UV is determined for different operational conditions. Finally, the contribution of each oxidation pathway is quantified; a higher contribution of the radical reaction than that of the direct photolysis was found in all cases.

Alkanesulfonic Acids↗
PubMed2003

GC Behavior of disaccharide trimethylsilyl oximes.

Twenty-five disaccharides are converted to trimethylsilyl oximes and injected on two capillary columns of different polarities (methyl and phenyl-methyl silicone). Their Kovats retention indices are determined at three temperatures. Multivariate data analysis is used in order to obtain relations between retention and some structural features. Phenylmethyl silicone have better chromatographic characteristics for the assayed compounds. The two columns can provide useful chromatographic information when a very complex disaccharide mixture has to be analyzed.

Journal Article↗
PubMed2003

Pre-test prediction models of BRCA1 or BRCA2 mutation in breast/ovarian families attending familial cancer clinics.

OBJECTIVE: To test whether statistical models developed to calculate pre-test probability of being a BRCA1/2 carrier can differentiate better between the breast/ovarian families to be referred to the DNA test laboratory. STUDY DESIGN: A retrospective analysis was performed in 109 Spanish breast/ovarian families previously screened for germline mutations in both the BRCA1 and BRCA2 genes. Four easy to use logistic regression models originally developed in Spanish (HCSC model), Dutch (LUMC model), Finnish (HUCH model), and North American (U Penn model) families and one model based on empirical data of Frank 2002 were tested. A risk counsellor was asked to assign a subjective pre-test probability for each family. Sensitivity, specificity, negative and positive predictive values, and areas under receiver operator characteristics (ROC) curves were calculated in each case. Correlation between predicted probability and mutation prevalence was tested. All statistical tests were two sided. RESULTS: Overall, the models performed well, improving the performances of a genetic counsellor. The median ROC curve area was 0.80 (range 0.77-0.82). At 100% sensitivity, the median specificity was 30% (range 25-33%). At 92% sensitivity, the median specificity was 42% (range 33.3-54.2%) and the median negative predictive value was 93% (range 89.7-98%). BRCA1 families tended to score higher risk than BRCA2 families in all models tested. CONCLUSIONS: All models increased the discrimination power of an experienced risk counsellor, suggesting that their use is valuable in the context of clinical counselling and genetic testing to optimise selection of patients for screening and allowing for more focused management. Models developed in different ethnic populations performed similarly well in a Spanish series of families, suggesting that models targeted to specific populations may not be necessary in all cases. Carrier probability as predicted by the models is consistent with actual prevalence, although in general models tend to underestimate it. Our study suggests that these models may perform differently in populations with a high prevalence of BRCA2 mutations.

BRCA1 Protein↗
PubMed2003

[Multicenter cohort of patients with HIV infection in the Madrid south-eastern metropolitan crown (COMESEM): basis, organization and initial results].

BACKGROUND: In order to evaluate changes related to the effect of new anti-retroviral agents and preventive programs, cohort studies of patients with HIV in our environment are needed. METHODS: Cohort study of patients diagnosed of HIV infection in the five hospitals included in the Madrid metropolitan south-eastern crown (COMESEM), which attend a population of 1,300,000 inhabitants. RESULTS: A total of 5,532 patients had been recruited until August 2001 (with a follow-up of 34,227 patients-year). The male/female ratio was 3/1. As for the transmission mechanism, 72.9% were parenteral drug users (PDU), 13.7% heterosexuals (HTX) and 8% of males having sex with males (MSM). The maximal figure of diagnosis per year corresponded to 1991 for PDU, 1993 for MSM and 1995 for heterosexuals. A decline in the number of diagnosed patients was observed for all groups, but MSM showed an increase in the year 2001 for the first time. Notably, among HTX, a growing and sustained trend was observed of patients not born in Spain (0% in 1993 and 50% in 2001; p < 0.001). CONCLUSIONS: Establishing a large cohort of HIV infected patients based upon medium-sized hospitals is possible. The analysis of data derived from this cohort allows the early detection of changes in the clinical and epidemiological profile of HIV infection.

Adult↗