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S Muñoz

Publications and source records attributed to S Muñoz.

At least 19 recordsLinked to original sources
PubMed2006

Analysis of the electric field induced forces in erythrocyte membrane pores using a realistic cell model.

We calculate the induced electric stress forces on transient hydrophobic pores in the membrane of an erythrocyte exposed to an electric field. For this purpose, we use a finite element numerical technique and a realistic shape for the biconcave erythrocyte represented by a set of parametric equations in terms of Jacobi elliptic functions. The results clearly show that the electrical forces on the base and sidewalls of the pore favour the opening of the pore. A comparison of the force densities obtained for an unstretched flat membrane and for the realistic erythrocyte model shows that the thinning and curvature of the membrane cannot be neglected. We also show that the pore deformation depends strongly on the orientation of the pore with respect to the external field, and in particular is very small when the field is tangent to the membrane surface.

Biomechanical Phenomena↗
PubMed2005

[Effect of inspiratory muscle training on muscle strength and quality of life in patients with chronic airflow limitation: a randomized controlled trial].

OBJECTIVE: Chronic airflow limitation (CAL) is a significant cause of illness and death. Inspiratory muscle training has been described as a technique for managing CAL. The aim of the present study was to evaluate the effectiveness of inspiratory muscle training on improving physiological and functional variables. PATIENTS AND METHODS: Randomized controlled trial in which 35 patients with CAL were assigned to receive either an experimental (n=17) or control (n=18) intervention. The experimental intervention consisted of 2 months of inspiratory muscle training using a device that administered a resistive load of 40% of maximal static inspiratory mouth pressure (PImax). Inspiratory muscle strength, exercise tolerance, respiratory function, and quality of life were assessed. RESULTS: Significant improvement in inspiratory muscle strength was observed in the experimental training group (P=.02). All patients improved over time in both groups (P<.001). PImax increased by 8.9 cm H2O per month of training. Likewise, the health-related quality of life scores improved by 0.56 points. CONCLUSION: Use of a threshold loading device is effective for strengthening inspiratory muscles as measured by PImax after the first month of training in patients with CAL. The long-term effectiveness of such training and its impact on quality of life should be studied in a larger number of patients.

Breathing Exercises↗
PubMed2005

[Initial experience with Arndt-type bronchial blockers in thoracic surgery].

OBJECTIVES: The aim of the present study was to consider the feasibility of Arndt-type bronchial blockers in thoracic surgery. PATIENTS AND METHODS: We enrolled the first 11 patients undergoing uncomplicated thoracic surgery expected to be of short duration. The following variables were recorded: age, weight, height, diagnosis, type of surgery, side where the blocker was used, time needed for positioning, the number of times the blocker was malpositioned according to fiberoptic bronchoscopy, time of lung isolation, duration of surgery, and effectiveness of lung collapse. RESULTS: Eleven blockers were placed in 5 women and 6 men aged between 25 and 81 years old (mean +/- SD, 52.73 +/- 22.12 years). Weight ranged from 45 to 88 Kg (mean 65.82 +/- 11.86 Kg). Height ranged from 157 to 175 cm (mean 166 +/- 5.76 cm). Time needed for positioning the blocker ranged from 2 to 30 minutes (median 5 minutes, interquartile range 1-12). According to fiberoptic bronchoscopy, the bronchial cuff was malpositioned, with herniation into the carina, in 1 case. Duration of surgery ranged from 30 minutes to 4 hours (median 70 minutes, interquartile range 50-210 minutes). Lung collapse was excellent in 9 cases and acceptable in 2 according to the surgeon. CONCLUSIONS: Our initial experience with bronchial blockers in elective surgery has shown that time for initial positioning is acceptably short and that surgical conditions are excellent in most cases.

Adult↗
PubMed2005

[Comparison of the bispectral index and spectral entropy in gynecological surgery].

OBJECTIVES: Spectral entropy quantifies variations in cortical electrical activity measured by electroencephalography and frontal activity measured by electromyography. The aim of this study, in the context of general anesthesia, was to compare bispectral index values with the two components of spectral entropy: state entropy and response entropy. MATERIAL AND METHODS: Sixteen women (ASA I-II) undergoing gynecological surgery were enrolled. The bispectral index was maintained between 40 and 50 for all patients. Both sensors, for monitoring the bispectral index and spectral entropy, were placed on each patient. Simultaneous readings were recorded at the following moments: operating room arrival, induction, relaxation, intubation, switching on the vaporizer, start of surgery, traction of the intestinal mesenteries and maneuvering of the electric scalpel, switching off the vaporizer, end of surgery, during cough, extubation, and eye opening. The data sets were subjected to analysis of variance, and the intraclass correlation coefficient (ICC) was used to analyze agreement. RESULTS: Differences between mean values of the bispectral index, state entropy and response entropy were observed at operating room arrival, intubation, and induction. Differences when the patient awakened from anesthesia were observed only between the bispectral index and response entropy, on the one hand, and state entropy on the other. There was no agreement (ICC<0.7) upon operating room arrival, maneuvering the electric scalpel, or awakening from anesthesia. CONCLUSION: The bispectral index, state entropy, and response entropy show good agreement during recordings that reflect the effects of anesthesia. The differences observed at baseline and upon awakening can be attributed to frontal electromyographic activity. Distinguishing cortical electrical activity from frontal electromyographic activity may provide additional information in these situations.

Anesthesia, General↗
PubMed2004

Transmembrane voltage induced on altered erythrocyte shapes exposed to RF fields.

In this article, the transmembrane voltage induced on erythrocyte, codocyte, ovalocyte and spherocyte cell models exposed to a linearly polarised electromagnetic plane wave of frequency 1800 MHz is calculated. For this purpose, a finite element (FE) numerical technique with adaptive meshing is used. The results show that the value of the induced voltage on the original erythrocyte shape is higher than the one observed on the rest of the altered cell geometries studied. The erythrocyte shape and the membrane electric permittivity are shown to play a fundamental role on the values of the induced transmembrane voltage.

Animals↗
PubMed2004

Trypanosoma cruzi isolates from Chile are heterogeneous and composed of mixed populations when characterized by schizodeme and Southern analyses.

In total, 61 Chilean isolates of Trypanosoma cruzi, were analysed using schizodeme and Southern analysis, using as probes the highly variable regions of minicircles from cloned parasites. Isolates were collected and amplified from domestic and wild triatomines, and from infected subjects in all the endemic areas of Chile. Three major parasite genotypes could be detected in the domestic transmission cycle, whilst 1 major T. cruzi genotype is circulating in the wild transmission cycle. Schizodeme analysis suggested that T. cruzi isolates are mixed populations, whereas the Southern analyses detected only 3 mixed isolates using 4 selected minicircle segments as probes.

Animals↗
PubMed2004

Prevalence of esophageal disorders in patients with recurrent chest pain.

The objective of this study is to determine the prevalence of esophageal disorders (ED) associated with recurrent chest pain (RCP) and the utility of esophageal functional tests (EFT) in the study of these patients. The cross-sectional study was conducted at Hospital Clínico de La Frontera, Chile. One hundred and twenty-three patients with RCP were studied using esophageal manometry, edrophonium stimulation and 24-h pH monitoring. The performance of EFT was considered acceptable when they were capable of finding ED. To state the probability that RCP had an esophageal origin, patients were classified according to whether their pain had a probable, possible or unlikely esophageal origin. The prevalence of ED was determined according to diagnoses obtained after applying EFT and a multivariate analysis was performed to examine the association between the esophageal origin of RCP and ED. Rates of correct diagnosis of 65.9%, 56.9% and 31.7% was verified for 24-h pH monitoring, esophageal manometry and edrophonium stimulation, respectively. In 38.2% of patients with RCP, the pain was probably of esophageal origin, in 42.3% there was a possible esophageal origin and in 19.5% an unlikely esophageal origin. A 44.7% prevalence of GERD, 26.8% of GERD with secondary esophageal motor dysfunction and 8.9% of pure esophageal motor dysfunction were verified. The multivariate analysis allowed us to verify the association between the probability of esophageal origin of RCP, the variables RCP duration, esophagitis and dysphagia coexistence (P= 0.037, P= 0.030 and P= 0.024, respectively), and a statistically significant association between ED and dysphagia coexistence (P= 0.028). A high prevalence of ED was identified in patients with RCP.

Adult↗
PubMed2004

Superior mesenteric venous thrombosis: a retrospective study of thirteen cases.

OBJECTIVE: To analyze the epidemiology, associated risk factors, clinical presentation, diagnostic methods, treatment, and evolution of patients diagnosed with superior mesenteric venous thrombosis (SMVT) at an university hospital in Madrid. EXPERIMENTAL DESIGN: Retrospective and descriptive study. We review the medical records of patients with this diagnosis in our hospital from January 1998 to December 2002. Data were processed by using the SPSS vs. 11 software. PATIENTS: All thirteen subjects diagnosed with SMVT in that period were included. RESULTS: Associated risk factors included tumoral conditions (5 patients), acute abdominal pathology (2), polyglobulia (1), prothrombin gene mutation (1), and anticardiolipin antibodies (1). No predisposing factor was found in 3 patients. Clinical presentation for all patients was abdominal pain, with nausea and vomiting being the second symptom in frequency (7). The diagnosis was reached by abdominal CT (9), arteriography (2), ultrasounds (1), and histology after intestinal resection (1). Treatment with only anticoagulation was initiated in 4 patients, whereas anticoagulation and surgery were performed in 5 cases. In 4 subjects no specific treatment was prescribed and only palliative measures were established due to a baseline end-stage condition. Five patients died, and four of them had a neoplasic condition as associated risk factor. Mortality in our series was 38.5%. CONCLUSIONS: SMVT is a very rare disease that is often associated with neoplasic pathology, which influences its high mortality. Due to non specific symptoms, imaging is essential for the diagnosis and the detection of associated risk factors. In our series, computed tomography imaging was the most profitable test.

Aged↗
PubMed2003

Analysis of 35 priority semivolatile compounds in water by stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry. I. Method optimisation.

A multiresidue method for the determination of 35 organic micropollutants (pesticides and polycyclic aromatic hydrocarbons) in water has been optimised using stir bar sorptive extraction (SBSE) and thermal desorption coupled to capillary gas chromatography-mass spectrometry (GC-MS). In the present work, the different parameters affecting the extraction of the analytes from the water samples to the PDMS-coated stir bars and optimisation of conditions affecting thermal desorption are investigated. The optimised conditions consist of a 100-ml water sample with 20% NaCl addition extracted with 20 mm length x 0.5 mm film thickness stir bars at 900 rpm during 14 h at ambient temperature. Desorption is carried out at 280 degrees C during 6 min under a helium flow of 75 ml/min in the splitless mode while maintaining a cryofocusing temperature of 20 degrees C in the programmed-temperature vaporisation (PTV) injector of the GC-MS system. Finally, the PTV injector is ramped to a temperature of 280 degrees C and the analytes are separated in the GC and detected by MS using full scan mode (m/z 60-400). Under the described conditions, the good repeatability, high analyte recoveries and robustness, make SBSE a powerful tool for routine quality control analysis of the selected semivolatile compounds in water samples.

Adsorption↗
PubMed2003

Role of placental alkaline phosphatase in the internalization of trypomatigotes of Trypanosoma cruzi into HEp2 cells.

BACKGROUND: In vitro, Trypanosoma cruzi invades a wide variety of mammalian cells by an unique process that is still poorly understood. Trypomastigotes adhere to specific receptors on the outer membrane of host cells before intracellular invasion, causing calcium ion mobilization and rearrangement of host cell microfilaments. OBJECTIVE: To test if placental alkaline phosphatase (PLAP), a trophoblast plasma membrane protein anchored by a glycosylphosphatidylinositol molecule, is involved in the transplacental transmission of this parasite. METHOD: We cultured HEp2 cells with the parasite and studied PLAP and actin microfilaments. The results were correlated with invasion rate. RESULTS: Human HEp2 tumour cells express PLAP. HEp2 cells infected with trypomastigotes showed alteration in their alkaline phosphatase activity and a different pattern of actin organization, compared to control cells. Perturbation of PLAP from HEp2 cells before infection with T. cruzi trypomastigotes decreased the invasion rate. CONCLUSION: Placental alkaline phosphatase could be involved in the internalization of T. cruzi into HEp2 cells, via activation of tyrosine kinase and rearrangement of actin microfilaments.

Actin Cytoskeleton↗
PubMed2002

Phenotypic and molecular characterization of chickpea rhizobia isolated from different areas of Morocco.

AIMS: To determine the biodiversity of rhizobial strains nodulating Cicer arietinum L. in representative soils from various areas of Morocco. METHODS AND RESULTS: Symbiotic traits, utilization of 49 carbohydrate sources, resistance to antibiotics and heavy metals, tolerance to salinity, to extreme temperatures and pH were studied as phenotypic markers. In addition, restriction fragment length polymorphism (RFLP) of PCR-amplified 16S rDNAs were compared with those of reference strains. Numerical analysis of the phenotypic characteristics showed that the 48 strains studied fell into three distinct groups. RFLP analysis of 16S rRNA genes revealed an additional heterogeneity and four ribotypes were identified. CONCLUSIONS: Chickpea rhizobia isolated from Moroccan soils are both phenotypically and genetically diverse. Most of these rhizobia belong to the Mesorhizobium genus. However, some strains originating from a particular soil appeared to have 16S rRNA genes similar to Sinorhizobium as well as very distinct auxanographic characteristics compared with Mesorhizo- bium isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: A well characterized collection of chickpea-nodulating rhizobia in representative soils of Morocco has been generated, which can be used to develop efficient inoculants for this crop. This is the first report evidencing that chickpeas may be nodulated by bacteria from the Sinorhizobium genus.

Alphaproteobacteria↗
PubMed2001

Laparoscopic pericystectomy for liver hydatid cysts.

BACKGROUND: The laparoscopic approach for managing of liver echinococcosis is a controversial issue because of scarce experience worldwide. The aim of this report is to describe the technical details of our laparoscopic method and present our results. METHODS: Consecutive cases of liver echinococcosis managed by laparoscopic surgery are reported. Thoracic x-ray and abdominal ultrasound had been performed previously. The following aspects were considered as selection criteria: unique cyst located in segments III, IV, V, VI, and VIII; diameter less than 7 cm; and no evidence of infection or calcification. An evacuating puncture was performed, germinative membrane removed, and pericystectomy performed, which extirpated the pericystic structure with the surrounding liver parenchyma. Specimens were removed in a plastic bag through one of the ports. Surgical morbidity, hospital stay, time until return to work, and evidences of hydatid recurrence were measured. RESULTS: Surgery was performed on eight patients (5 women and 3 men) with a mean age of 44.9 years (range, 22-83 years) who had a liver hydatid cyst with a mean diameter of 6.6 cm (range, 5-7 cm). During a mean follow-up period of 30 months (range, 23-44 months), no morbidity or hydatid recurrence were verified. Hospital stay was 2 days in all cases, and return to work was within 15 days. CONCLUSION: This laparoscopic technique, applied with selective criteria, can be a useful alternative for treating patients with liver hydatidosis because its results are comparable with those for open surgery studies involving similar follow-up time.

Adult↗
PubMed2001

Analysis of the influence of the cell geometry, orientation and cell proximity effects on the electric field distribution from direct RF exposure.

This paper shows the importance of using a cell model with the proper geometry, orientation and internal structure to study possible cellular effects from direct radiofrequency exposure. For this purpose, the electric field intensity is calculated, using the finite element numerical technique, in single- and multilayer spherical, cylindrical and ellipsoidal mammalian cell models exposed to linearly polarized electromagnetic plane waves of frequencies 900 and 2450 MHz. An extensive analysis is performed on the influence that the cell geometry and orientation with respect to the external field have in the value of the electric field induced in the membrane and cytoplasm. We also show the significant role that the cytoplasmic and extracellular bound water layers play in determining the electric field intensity for the cylindrical and ellipsoidal cell models. Finally, a study of the mutual interactions between cells shows that polarizing effects between cells significantly modify the values of field intensity within the cell.

Cell Membrane↗
PubMed2001

[Clinical heterogeneity of the chromosome 22q11 microdeletion syndrome].

BACKGROUND: DiGeorge anomaly, velocardiofacial syndrome and conotruncal anomaly face syndrome are part of a group of congenital malformations of the chromosome 22q11 microdeletion syndrome, since they share certain phenotypic features as well as a common genetic abnormality. The malformations include mild facial dysmorphic features, conotruncal heart defects, thymic and parathyroid hypoplasia or aplasia and cleft palate. AIM: To describe the initial clinical presentation of children with clinical and molecular diagnosis of 22q11 microdeletion. PATIENTS AND METHODS: Ten children (seven male) with the phenotypic features of 22q11 microdeletion syndrome are reported. Microdeletion was detected in peripheral lymphocytes by fluorescent in situ hybridisation (FISH) with the TUPLE-1 DNA probe. RESULTS: Two children had abnormal karyotypes, one of them had a visible deletion and another child had an unbalanced translocation inherited from his mother who had a balanced translocation between chromosomes 14 and 22. Two of the 10 patients had an anterior laryngeal web, a malformation infrequently described in this syndrome. Five patients had the diagnosis of DiGeorge anomaly, had a more serious clinical presentation and a higher early mortality. CONCLUSIONS: The high frequency of the 22q11 microdeletion syndrome, estimated at 1:5.000 newborns, and its variable presentations requires a high level of awareness for its early diagnosis and appropriate management of associated complications.

Child↗
PubMed2001

Association between prematurity and maternal anemia in Venezuelan pregnant women during third trimester at labor.

To determine the association and its magnitude between prematurity and anemia in women in their third trimester of pregnancy and at labor. An incident case-control study was conducted using 2 controls per case. Data was obtained in a tertiary hospital in Valencia, Venezuela. A total of 543 women who delivered between May and December 1996 entered into the study. Women having a preterm delivery, less than 37 weeks of gestation at delivery, were defined as cases (n = 181). Anemia was defined according to WHO as Hb less than 11 g/dL. Logistic regression was used to analyze the data and likelihood ratio test was done for model comparison. Maternal anemia was found to be significantly associated with prematurity (Odds Ratio: 1.70; 95% CI = 1.18 to 2.57 P = .001), after adjusting for Placental Abruption, PROM, Previous Premature Labor, Prenatal Care Visits, and Uterine Bleeding during more than one trimester. Maternal anemia at the end of the third trimester of pregnancy, at labor, was associated with an increased risk of prematurity.

Anemia↗
PubMed2001

Walnut-enriched diet increases the association of LDL from hypercholesterolemic men with human HepG2 cells.

In a randomized, cross-over feeding trial involving 10 men with polygenic hypercholesterolemia, a control, Mediterranean-type cholesterol-lowering diet, and a diet of similar composition in which walnuts replaced approximately 35% of energy from unsaturated fat, were given for 6 weeks each. Compared with the control diet, the walnut diet reduced serum total and LDL cholesterol by 4.2% (P = 0.176), and 6.0% (P = 0.087), respectively. No changes were observed in HDL cholesterol, triglycerides, and apolipoprotein A-I levels or in the relative proportion of protein, triglycerides, phospholipids, and cholesteryl esters in LDL particles. The apolipoprotein B level declined in parallel with LDL cholesterol (6.0% reduction). Whole LDL, particularly the triglyceride fraction, was enriched in polyunsaturated fatty acids from walnuts (linoleic and alpha-linolenic acids). In comparison with LDL obtained during the control diet, LDL obtained during the walnut diet showed a 50% increase in association rates to the LDL receptor in human hepatoma HepG2 cells. LDL uptake by HepG2 cells was correlated with alpha-linolenic acid content of the triglyceride plus cholesteryl ester fractions of LDL particles (r(2) = 0.42, P < 0.05). Changes in the quantity and quality of LDL lipid fatty acids after a walnut-enriched diet facilitate receptor-mediated LDL clearance and may contribute to the cholesterol-lowering effect of walnut consumption.

Adult↗
PubMed2001

[Conjugal violence in the city Temuco. Prevalence studies and associated factors].

BACKGROUND: Violence against women is a recognized public health problem in developed countries. There is increasing awareness on family violence in Chile, but there is scant information about its prevalence. AIM: To determine the prevalence of family violence against women in a population sample in Temuco, Chile. MATERIAL AND METHODS: A standardized questionnaire about family violence was applied to a sample of 422 women at their homes. The questionnaire had six sections that included a list of violent behaviors from husbands or partners, a standardized instrument to assess mental health and alcohol consumption by the couple, history of child abuse, community support, type of employment and years of school education. RESULTS: Forty nine percent of women reported psychological aggression, 13% reported physical violence and 5.5%, sexual violence. The presence of anxiety or depressive symptoms, being witness of violence between parents during childhood, a lower educational level, being a housewife, alcohol abuse and lack of community support were risk factors for violence among women. Among men, the history of child abuse, a lower education level, and alcohol abuse were identified as risk factors for violent behaviors. CONCLUSIONS: Conjugal violence is a significant mental health problem in Temuco, Chile.

Adolescent↗