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Biomedical subjects

C García

Publications and source records attributed to C García.

At least 37 records · Page 2Linked to original sources
PubMed2004

Anthropometric measurements in the elderly population of Santiago, Chile.

OBJECTIVE: There are few studies on anthropometry and nutritional status in large and representative samples of elderly populations in Chile and South America. We describe age and sex differences in weight, height, body mass index, knee height, waist circumference, midarm circumference, triceps skinfold thickness, arm muscle area, and calf circumference in Chilean elderly subjects. METHODS: This was a population-based, cross-sectional study. A total of 1220 elderly persons (819 women and 411 men; age range, 60-99 y) were recruited in the city of Santiago (Chile) through a probabilistic sampling procedure carried out from October to December 1999. RESULTS: Men were significantly heavier and taller than women in all age groups, whereas body mass index values were significantly higher in women than in men. All anthropometric variables showed a decrease in average values with aging in men and women. The apparent negative slopes for the decline in average values of body weight with aging was of greater magnitude in women than in men (-0.42 kg/y and -0.54 kg/y in male and female subjects, respectively). However, significant age x sex interaction was detected only for triceps skinfold thickness. In women, quadratic terms for age provided a significantly better fit than did the simple linear model for the association between age and weight, body mass index, waist circumference, triceps skinfold thickness, calf circumference, or midarm circumference. CONCLUSION: These observations indicated that body weight changes associated with aging might be more severe in Chilean women than in men, probably determining a differential pattern of lean and fat mass loss.

Age Distribution↗
PubMed2004

A comparative study of the activation peptide of carboxypeptidase B and trypsinogen as early predictors of the severity of acute pancreatitis.

BACKGROUND: Serum and urine concentrations of the activation peptide of carboxypeptidase B (CAPAP) and urinary trypsinogen activation peptide (TAP) as prognostic markers in acute pancreatitis were compared. METHOD: Fifty-two patients with acute pancreatitis hospitalized within 24 hours after symptom onset were prospectively studied. Blood and urine samples were obtained during the first 3 days of the hospital stay. RESULTS: Pancreatitis was severe in 17 patients and mild in 35 (Atlanta criteria). Median serum CAPAP levels on days 1 and 2 and of urine CAPAP and TAP on days 1, 2, and 3 were significantly higher in severe pancreatitis than in mild disease. On the first day of admission, TAP was the most accurate predictor of severity (sensitivity, 92.3%; specificity, 80%; positive and negative predictive values, 63.2% and 96.6%, respectively), with a 4.61 positive likelihood ratio for a cutoff value of 18.10 nmol/L, whereas within 24 hours after symptom onset, urinary CAPAP was superior (sensitivity, 88.9%; specificity, 81.3%; positive and negative predictive values 72.7% and 92.9%, respectively), with a 4.72 positive likelihood ratio for a cutoff value of 15.45 nmol/L. CONCLUSION: Serum and urine CAPAP levels and urinary TAP are accurate in the early assessment of severity in acute pancreatitis. Urine CAPAP levels was the most accurate marker 24 hours after onset of symptoms.

Abdominal Pain↗
PubMed2004

The close relationship between estimated divergent selection and observed differentiation supports the selective origin of a marine snail hybrid zone.

To study the role of divergent selection in the differentiation of the two morphs in a hybrid zone of the intertidal snail Littorina saxatilis, we compared the strength of the divergent selection acting on a series of shell characters (as estimated by the viability of snails in a reciprocal transplant experiment) with the contribution of these characters to the phenotypic differences between the morphs. We found a close correlation between selection and differentiation, which suggests a cause-effect relationship, i.e. that all present differentiation is the result of past divergent selection. In addition, divergent selection was a very important component of the total natural selection acting on shell measures. These novel results support previous evidence, based on allozyme analysis, of a parapatric origin for this hybrid zone. We discuss possible limitations of this interpretation and the circumstances under which allopatric differentiation would produce the same results. Phenotypic analysis of divergent selection may be a useful method of investigating the evolutionary mechanisms involved in differentiation processes.

Animals↗
PubMed2004

Bifid mandibular condyle: archaeological case report of a rare anomaly.

In this paper, an archaeological case of unilateral bifid mandibular condyle is presented. This uncommon anomaly is characterized by a division of the mandibular condylar head. In this case, the left condyle was divided into two articulating surfaces oriented mediolaterally; two articular facets on the anterior wall of the glenoid fossa for the double condyle were observed. The morphological and radiological analysis do not show any evidence of injuries or degenerative pathology. Taking into account the two main causes of bifid condyle suggested in the literature (traumatic and developmental), an embryopathy by teratogenic agents is proposed as a possible aetiology of the bifid condyle reported here.

History, Ancient↗
PubMed2004

[Bilateral superior oblique palsy and botulinum toxin].

PURPOSE: To study the effectiveness of botulinum toxin in the treatment of bilateral acquired oblique superior palsy. MATERIAL AND METHOD: Five patients with bilateral asymmetrical acquired superior oblique palsy were treated with periodical injections of botulinum toxin in the inferior oblique and rectus muscles (2.5-5 U). The average age of the sample was 37.4 years. A trauma etiology was present in four cases. Treatment was applied at two months after the beginning of the illness in two cases, at four months in another two cases, and at one year in the other patient. RESULTS: A good result was achieved in three of the cases with botulinum toxin. Two patients required surgery. All of the patients were injected in the inferior obliques, and two cases were also injected in the inferior rectus. The number of injections ranged between four and six applications. It was considered to be a good result when diplopia was corrected in reading and primary position, and torticollis disappeared. Diplopia was not corrected in extreme lateral gazes and supraversion in two cases. CONCLUSIONS: Periodical botulinum toxin injections represent an alternative management to surgery in the treatment of bilateral acquired oblique palsy. In some cases botulinum toxin injections can prevent or decrease the number of surgical interventions

Adult↗
PubMed2004

Two-dimensional cellular automaton model for mixed-culture biofilm.

Structural and microbial heterogeneity occurs in almost any type of biofilm system. General approaches for the design of biofilm systems consider biofilms as homogeneous and of constant thickness. In order to improve the design of biofilms systems, models need to incorporate structural heterogeneity and the effect of inert microbial mass. We have improved a 2D biofilm model based on cellular automata (CA) and used it to simulate multidimensional biofilms with active and inert biomass including a self-organizing development. Results indicate that the presence of inert biomass within biofilm structures does not change considerably the substrate flux into the biofilm because the active biomass is located at the surface of the biofilm. Long-term simulations revealed that although the biofilm system is highly heterogeneous and the microstructure is continuously changing, the biofilm reaches a dynamic steady-state with prediction of biofilm thickness and substrate flux stabilizing on a delimited range.

Bacteria↗
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↗