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Biomedical subjects

C García

Publications and source records attributed to C García.

At least 19 recordsLinked to original sources
PubMed2004

Fatal case of community-acquired pneumonia caused by Legionella longbeachae in a patient with systemic lupus erythematosus.

Reported here is a rare case of atypical pneumonia due to a non- pneumophila Legionella sp. that occurred in a young patient with systemic lupus erythematosus. In spite of aggressive treatment, the patient died 24 h following admission to the intensive care unit. Legionella longbeachae was cultured from respiratory tract specimens and identified to the genus level by PCR and to the species level by an immunofluorescence test. Since most current laboratory tests for Legionella spp., including urinary antigen and serology, cannot detect infections caused by non- pneumophila Legionella spp., culture on legionella-selective media should be strongly considered when diagnosing immunosuppressed patients with pneumonia.

Adult↗
PubMed2003

Comparison between cardiac output measured by the pulmonary arterial thermodilution technique and that measured by the femoral arterial thermodilution technique in a pediatric animal model.

This study compares the correlation between two methods for the determination of cardiac output-the pulmonary arterial thermodilution technique using the Swan-Ganz catheter and the femoral arterial thermodilution technique using a pulse contour analysis computer (PiCCO) catheter. We performed a prospective animal study using 16 immature Maryland pigs weighing 9 to 16 kg. A 5.5- or 7.5-Fr Swan-Ganz catheter was introduced into the femoral or jugular vein, and a 4- or 5-Fr arterial PiCCO catheter was introduced into the femoral artery. In each animal, we made measurements of cardiac output at 30-minute intervals, simultaneously by pulmonary arterial thermodilution and femoral arterial thermodilution, before, during, and after hemodiafiltration carried out via different venous catheters, recording a total of 78 measurements. The mean Swan-Ganz cardiac output was 2.22 +/- 0.94 L/min, and mean PiCCO cardiac output was 1.94 +/- 0.80 L/min (no significant difference). The mean difference (bias) of differences (limits of agreement) was 0.2812. The differences between the methods increased with higher cardiac output, but the percentage differences in relation to cardiac output remained stable. Good correlation was found between the two methods: single-measure intraclass correlation was 0.8892 (95% confidence interval, 0.54-0.95). There were no differences between the 5.5- and 7.5-FR Swan-Ganz catheters or between the 4- and 5-Fr PiCCO catheters. Femoral arterial thermodilution cardiac output measurements correlated well with pulmonary arterial thermodilution cardiac output measurements in a pediatric animal model.

Animals↗
PubMed2003

Two new mutations in cis on (G)gamma chain of fetal hemoglobin: Hb F-Madrid [G gamma 50(D1)Ser-->Cys] and [G gamma 75(E19)Ile-->Thr].

We describe a new structural hemoglobin variant of (G)gamma with two amino acid replacements in cis found in the umbilical cord blood of a neonate in Madrid, Spain. The substitutions were identified on exon 2 of the (G)gamma globin gene, at codon 50 (T CT-->T GT) and at codon 75 (A TA-->A CA). We have named it Hb F-Madrid. The father of the propositus was the carrier of the same (G)gamma chain variant and, moreover, molecular study of alpha genes revealed the loss of an alpha gene (-alpha(3.7)/alpha alpha) both in the propositus and his mother.

Base Sequence↗
PubMed2003

Bioremediation of soil degraded by sewage sludge: effects on soil properties and erosion losses.

Soils in the Mediterranean area are very prone to erosion due to the loss of organic matter and the consequent lack of protective vegetation. In this experiment a Mediterranean degraded soil with a 15% slope was amended at a rate of 250 t ha(-1) wet weight with sewage sludge and with a mixture of sewage sludge and barley straw (70% carbon from sewage sludge and 30% from the straw) in order to study their influence on soil structure recovery and hence the soils's resistance to erosion processes. Both types of organic amendment led to an improvement in several soil properties (physical, biological, and microbiological) as a result of the spontaneous growth plant covering that became evident three months after amendment. This vegetation remained throughout the two years of the experiment and prevented the water erosion processes that normally precede soil degradation. Amendment by sewage sludge alone reduced soil loss by 80% compared with the control soil, while the mixture that included both sewage sludge and barley straw reduced losses by 84%, both reducing runoff by 57%. The amended soils showed increases in the percentage of stable aggregates, the levels of the total and water-soluble C fractions, microbial biomass C, basal respiration, and the activity of the different enzymes involved in the biogeochemical cycles of C, N, and P. The results confirm the usefulness of sewage sludge as an organic amendment for recovering damaged soils.

Biodegradation, Environmental↗
PubMed2003

Persistence of intracranial diastolic flow in transcranial Doppler sonography exploration of patients in brain death.

OBJECTIVE: The persistence of cerebral blood flow (CBF) in patients with whole brain death (BD) diagnosis is an unusual phenomenon. We describe patients with whole BD diagnosed despite persistence of intracranial blood flow on transcranial Doppler sonography (TDS). MATERIALS AND METHODS: From January 2001 to December 2002, we reviewed the records of 11 patients. Etiology of BD was craniocephalic trauma in 2 cases, schemic cerebrovascular accident (CVA) in 4 cases, Hemorrhagic CVA in 3 cases, subaracnoid hemorrhage in 1 case, and acute hydrocephalus in 1 case. Six patients had a cerebral decompressive mechanism. In all patients, TDS was used to confirm BD after clinical diagnosis. Additionally, all patients underwent an electroencephalogram (EEG). In 3 patients cerebral angiography (CA) and in 2 others radionuclide angiography (RA) with Tc99m HMPAO were done. RESULTS: All TDS studies showed persistent telediastolic positive flow in at least 1 artery. Because the TDS did not confirm the clinical diagnosis of BD, EEG tests were performed showing silence of bioelectrical activity. Those cases showed CA or RA results with a complete absence of CBF. CONCLUSION: The TDS technique directly evaluates the intracranial but not the intracerebral circulation. For this reason, during the BD diagnosis for patients with previous decompressive techniques, it was possible to find persistence of intracranial telediastolic flow using TDS. In those cases, it is advisable to use other tests to confirm the clinical diagnosis of BD.

Adult↗
PubMed2002

[HIV prevalence among homosexual and bisexual men in Spain, 1992-2000].

BACKGROUND: Our purpose was to describe the time trend in HIV seroprevalence among homo/ bisexual men. SUBJECTS AND METHOD: We analyzed 9,383 homo/ bisexual men who had a first voluntary test for HIV in 10 Spanish clinics from 1992 to 2000. RESULTS: HIV prevalence decreased from 20.3% in 1992 to 8.4% in 2000. In the multivariate analysis this decline appeared independently associated with the testing year and the birth cohort. CONCLUSIONS: New generations of voluntarily tested homo/bisexual men are less infected by HIV, but it is yet necessary to intensify the prevention programs.

Adolescent↗
PubMed2002

Nitrogen mineralisation potential in calcareous soils amended with sewage sludge.

Mineralisation of organic N is an important consideration when determining the annual amount of sewage sludge to be applied to agricultural soils. The mineralisation of sludge organic N was studied in two different textured soils (clayey and sandy soil) treated with aerobic and anaerobic sludge at two different rates (30 and 50 g sludge kg(-1) soil). The mineralisation of sludge organic N was determined during 20 weeks incubation period by analysis of inorganic N produced by a non-leached procedure. Sludge organic N mineralisation was influenced by soil type, organic N mineralisation being greater in the sandy soil (from 30% to 41%) than in the clayey soil (from 13% to 24%). Mineralisation rates decreased rapidly the first two weeks, followed by a slower decrease with time. Although total mineralisation increased with sludge addition rate, net mineralisation decreased with sludge addition rate, probably due to denitrificaton losses. The aerobically treated sludge gave higher mineralisation rates than the anaerobically treated one. The values of N0 and k for treated soils varied depending on the type of sludge and soil.

Aerobiosis↗
PubMed2002

Accumulation of deleterious mutations: additional Drosophila melanogaster estimates and a simulation of the effects of selection.

We report an assay of egg-to-adult viability in full-sibling mutation accumulation (MA) lines derived from a completely homozygous population of Drosophila melanogaster and maintained for 210 generations. A simultaneous evaluation was also made of a large population derived from the same origin and maintained as a control for the same period. We also present computer simulations to explore the possible decline in viability of the control population due to mutation accumulation and the possible effect of selection within and between MA lines. For this purpose, we used two mutational models independent from the data analyzed and based on radically different assumptions. The first model implies a large number of mutations of small effect, whereas the second implies a much smaller number of mutations with much larger effects. The observed rate of decline in mean viability was very small but significant (0.077%). The rate of increase in among line variance (0.189 x 10(-3)) was similar to those obtained previously in the same lines. The simulation results indicated that a model of many mutations of small effect is incompatible with the evolution of the mean viability of the control and MA lines over generations, the distribution of line means after 210 generations of mutation accumulation, and the pattern of line extinction over generations. Basically, this model predicted a large drop in viability, both in the control and particularly the MA lines, that is not observed empirically. It also predicted a rate of line extinction too low in the early generations and too high in the later ones. In contrast, the model based on few mutations of large effect was generally consistent with all the observations.

Animals↗
PubMed2002

Intrinsic changes on automatism, conduction, and refractoriness by exercise in isolated rabbit heart.

We have studied the intrinsic modifications on myocardial automatism, conduction, and refractoriness produced by chronic exercise. Experiments were performed on isolated rabbit hearts. Trained animals were submitted to exercise on a treadmill. The parameters investigated were 1) R-R interval, noncorrected and corrected sinus node recovery time (SNRT) as automatism index; 2) sinoatrial conduction time; 3) Wenckebach cycle length (WCL) and retrograde WCL, as atrioventricular (A-V) and ventriculoatrial conduction index; and 4) effective and functional refractory periods of left ventricle, A-V node, and ventriculoatrial retrograde conduction system. Measurements were also performed on coronary flow, weight of the hearts, and thiobarbituric acid reagent substances and glutathione in myocardium, quadriceps femoris muscle, liver, and kidney, to analyze whether these substances related to oxidative stress were modified by training. The following parameters were larger (P < 0.05) in trained vs. untrained animals: R-R interval (365 +/- 49 vs. 286 +/- 60 ms), WCL (177 +/- 20 vs. 146 +/- 32 ms), and functional refractory period of the left ventricle (172 +/- 27 vs. 141 +/- 5 ms). Corrected SNRT was not different between groups despite the larger noncorrected SNRT obtained in trained animals. Thus training depresses sinus chronotropism, A-V nodal conduction, and increases ventricular refractoriness by intrinsic mechanisms, which do not involve changes in myocardial mass and/or coronary flow.

Animals↗
PubMed2001

Na+ dependent glutamate transporters (EAAT1, EAAT2, and EAAT3) in primary astrocyte cultures: effect of oxidative stress.

The Na+ -dependent L-glutamate transporters EAAT1(GLAST), EAAT2 (GLT-1) and EAAT3 (EAAC1) are expressed in primary astrocyte cultures, showing that the EAAT3 transporter is not neuron-specific. The presence of these three transporters was evaluated by RT-PCR, immunoblotting, immunocytochemical techniques, and transport activity. When primary astrocyte cultures were incubated with L-buthionine-(S,R)-sulfoximine (BSO), a selective inhibitor of gamma-glutamylcysteine synthetase, the GSH concentration was significantly lower than in control cultures, but the expression and amount of protein of EAAT1, EAAT2 and EAAT3 and transport of L-glutamate was unchanged. Oxidative stress was created by adding H(2)O(2) or tert.-butyl hydroperoxide (t-bOOH) to the primary astrocyte cultures and cell damage was evaluated by measuring activity of lactate dehydrogenase. Under oxidative stress, GSH levels were significantly lower than in control astrocytes; but the expression and the amount of protein of the three transporters remained unchanged. However, L-glutamate uptake was significantly lower in astrocytes under oxidative conditions when compared to controls. L-Glutamate uptake was not changed in the presence of ascorbate, but was partially recovered in the presence of DTT and GSH ethyl ester. This report emphasizes that oxidative stress and not GSH depletion alters transporter activity without changing transporter expression.

Amino Acid Transport System X-AG↗
PubMed2001

Intramolecular cyclization of tert-butyldiphenylallylsilane units and carbonyl groups: allylsilane terminated cyclization versus the ene reaction.

tert-Butyldiphenylsilylcopper reacts with allene to give an allylsilane-vinylcopper intermediate which upon treatment with alpha,beta-unsaturated ketones leads to allylsilane containing ketones resulting from conjugate addition. These oxoallylsilanes bearing the bulky tert-butyldiphenylsilyl group undergo highly selective intramolecular cyclizations when treated with Lewis acid affording unsaturated cyclopentanols. Two reactivity patterns are observed: allylsilane terminated cyclization involving elimination of silicon or an ene reaction without losing the silyl group. The pathway depends on the ability of a hydrogen beta to the carbonyl to be removed in an ene-type process. Alpha,beta-unsaturated acid chlorides lead to silylated cyclopentenones.

Journal Article↗
PubMed2001

On-line flow sample stacking in a flow injection analysis-capillary electrophoresis system: 2000-fold enhancement of detection sensitivity for priority phenol pollutants.

A flow injection analysis-capillary electrophoresis system has been used for on-line flow stacking of 11 US Environmental Protection Agency priority phenol pollutants. Samples containing low concentrations of phenols dissolved in deionised water are continuously delivered to the capillary opening by means of a peristaltic pump. The sample components stack at the boundary between the highly conductive separation electrolyte and the introduced sample. By selecting an appropriate electrolyte and stacking conditions the movement of the electrolyte solution inside the capillary can be reduced, thereby improving the stacking efficiency. The electrolyte used here contained 20 mM phosphate, 8% 2-butanol, and 0.001% hexamethonium bromide at pH 11.95, and the stacking was carried out at 2 kV for 240 s. These conditions allowed up to 2000-fold preconcentration of the selected phenols. No matrix removal was necessary.

Electrophoresis, Capillary↗
PubMed2001

Beta-hydroxy-gamma-lactones as chiral building blocks for the enantioselective synthesis of marine natural products.

The enantioselective synthesis of trans-(+)-laurediol, (2S,3S,5R)-5-[(1R)-1-hydroxy-9-decenyl]-2-pentyltetrahydro-3-furanol, and (2S,3S,5S)-5-[(1S)-1-hydroxy-9-decenyl]-2-pentyltetrahydro-3-furanol are described. In addition, a formal synthesis of trans-(-)-kumausyne is also developed. All the synthetic procedures have in common the use of enantiomerically enriched beta-hydroxy-gamma-lactones, easily available by Sharpless asymmetric dihydroxylation (AD) from the suitable beta,gamma-unsaturated ester. The use of Katsuki-Sharpless asymmetric epoxidation (AE) as an additional enantioselective reaction provides cyclic compounds of high enantiomeric purity.

Biological Products↗
PubMed2001

Serum leptin levels in cattle with different nutritional conditions.

The role of leptin as an energetic state indicator in cattle was evaluated correlating different nutritional conditions and serum leptin levels. Two experiments were developed. Experiment I: Polled Hereford heifers were fed in optimum conditions and assigned randomly to one of three treatment diets: grazing, grazing plus supplementation and feedlot. Experiment II: cattle were subjected to feed restriction (R). Serum leptin levels were measured at pre and post-feeding moments. Using serum free fatty acid (FFA), beta-OH Butyrate (beta-OHB) and protein concentration as serum energetic indicators in both experiments. In experiment I leptin values were significantly different between pre and post-feeding moments, similar differences were found among groups when the pre-feeding and post-feeding values were compared. These differences may be considered as changes associated to the control of food intake. In experiment II, the serum leptin levels in Group R were significantly lower. The poor energetic status of animals from group R was demonstrated by the serum FFA, beta-OHB and protein concentrations. These results suggest that the energetic status of animals is correlated with the serum leptin levels, tending to maintain the energetic homeostasis.

Journal Article↗
PubMed2001

[Pediatric lung resection. A case series and evaluation of postoperative lung function].

The most common causes of pulmonary lobectomy in children are congenital lung malformations (CLM) and bronchiectasias. Our aim was to present the causes and clinical course and lung function of lobectomized patients. Between 1990 and July 1999 27 lobectomies were performed on patients whose ages ranged from newborn to 14 years. Lobectomies were performed to correct CLM in 124 cases and for acquired pulmonary disease (APD) in 13. Among CLM cases, half (n = 7) had cystic adenomatoid malformation. Among the APD patients, 10 had bronchiectasias, with etiological confirmation in 6 cases (3 secondary to serious adenovirus infection). Mean hospital stay was 4.6 days among those who experienced no postoperative complications. Symptoms resolved after surgery for most symptomatic patients. Lung function tests could be carried out with 8 patients over 6 years old whose operations had taken place 7 to 78 months earlier (x = 35 months) and whose age at the time of surgery was a mean 7 years 6 months (range 60 to 144 months). Spirometry showed normal forced vital capacity for 7 of 8 patients (87 to 143% of theoretical value). Arterial oxygen saturation measured during and after a 6-minute walking test was normal for 7 of 8 patients. Chest films showed reduced lung volume on the affected side in 5 of 8 patients. In summary, lobectomy is a procedure with few complications. It requires a short hospital stay and has good postoperative prognosis. Function and x-ray studies show adequate lung growth and development, with normal lung function in those who could be so examined because they were old enough to cooperate.

Adolescent↗