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Biomedical subjects

S Arias

Publications and source records attributed to S Arias.

At least 19 recordsLinked to original sources
PubMed2004

Effectiveness and safety of enteral vancomycin to control endemicity of methicillin-resistant Staphylococcus aureus in a medical/surgical intensive care unit.

A prospective trial was undertaken to assess the effectiveness and safety of enteral vancomycin in controlling methicillin-resistant Staphylococcus aureus (MRSA) in an endemic setting. Over the 49 month period patients aged >14 years were enrolled, following admission to a medical/surgical intensive care unit (ICU) and expected to require ventilation for three days or more. A total of 799 patients were included in the trial. Period one, 1 July 1996-30 April 1997, (N=140), was observational. During period two, 1 May 1997-30 September 1998, (N=258), surveillance samples were obtained. MRSA carriers were isolated and received enteral vancomycin. During period three, 1 October 1998-31 July 2000, (N=400), all ventilated patients were given selective digestive decontamination (SDD) with polymyxin E, tobramycin, amphotericin B and vancomycin and four days of intravenous cefotaxime. The primary endpoints were: (1) incidence of patients with diagnostic samples positive for MRSA acquired on the ICU; (2) incidence of patients with vancomycin-resistant enterococci (VRE) in surveillance or diagnostic samples; (3) incidence of patients with samples positive for S. aureus with intermediate sensitivity to glycopeptides (GISA). The incidence of patients with MRSA in diagnostic samples were 31%, 14%, and 2% in periods one, two and three, respectively (P<0.001). There was a VRE outbreak involving 13 patients during period three. VRE disappeared with no change in policy. GISA was not detected. These findings support the effectiveness and safety of enteral vancomycin in the control of MRSA.

Aged↗
PubMed2000

Secular trend and intrapopulational variation in age at menopause in Spanish women.

Menopause is associated with the general ageing process and marks the end of follicular depletion, a process that begins in the intrauterine stage and lasts throughout the lifetime of women until their reproductive senescence. Controversy persists about whether the age at menopause is sensitive to the ecological determinants prevailing during the lifecycle or whether it has a predominantly genetic component that would allow groups of women to be characterized with respect to particular menstrual characteristics manifested throughout their fertile life. By contrast, there is a definite secular trend in age at menarche in populations that have registered improvements in their environment: sexual maturation is closely associated with the general processes of growth and development. These aspects were analysed in a sample of Spanish women, mothers and daughters, born between 1883 and 1941. The results show (a) indications--although not conclusive--of a secular trend in the age at menopause, (b) a possible association between the age at menopause of mothers and their daughters, and (c) an association at the individual level between age at menarche, particular characteristics of ovarian function (fetal loss) and age at menopause. The reproductive ageing process therefore seems to result from the expression of the influence of ecological conditions in which the lifecycle of the women develops and of a degree of heritability that affects not only the age at menopause but also a range of characteristics of ovarian function.

Age Factors↗
PubMed2000

Lifetime dietary change and its relation to increase in weight in Spanish women.

INTRODUCTION: Changes in dietary patterns and a decrease in physical activity have occurred in Western countries. These are factors in the variation in body composition observed in populations, characterized by a progressive accumulation of fat with age and a consequent increase in the risk of suffering from common chronic illnesses such as obesity, cardiovascular disease and cancer. OBJECTIVE: To investigate weight gain throughout the life-cycle and its relation to modifications in dietary patterns, analyzing the causes of these modifications and their implications for patterns of adult overweight and obesity. DESIGN: Cross-sectional sample of Spanish women from a socio-economically disadvantaged class. SUBJECTS: 1037 healthy perimenopausal women (age: 45-65 y). MEASUREMENTS: Juvenile body mass index (BMI), current BMI, food frequency questionnaire, retrospective food habits. RESULTS AND CONCLUSIONS: Of these women, 48.8% had changed their dietary habits during their lifetime. A change in diet due to migration or marriage occurred at approximately 20 years of age and was characterized by an increased frequency of consumption of foods rich in protein and complex carbohydrates, while a change due to illness occurred at around 50 years of age and was characterized by a decrease in the consumption of these types of food. The change in dietary behavior due to migration was associated with weight gain. Weight gain was also inversely associated with BMI during youth; women who in their youth had a BMI<18.5 kg/m2 gained an average of 21.4 kg, compared with those with a BMI>27 kg/m2 in their youth, who gained an average of 5.4 kg. International Journal of Obesity (2000)24, 14-19

Aged↗
PubMed1999

Molarization of the lower second premolars.

This paper presents a case of extreme tooth variation. The patient was first observed during the mixed dentition period, when she presented a mild Class II malocclusion with increased overjet and acceptable overbite. In a panoramic radiograph, the presence of lower second premolars of disproportionate dimensions was discovered. When these oversized premolars erupted, the Class I malocclusion tended toward Class III, with an edge-to-edge bite. This created an unstable occlusion and the possible need for extractions.

Bicuspid↗
PubMed1999

A long-term evaluation of treated Class II division 2 malocclusions: a retrospective study model analysis.

Pre-treatment, end of treatment, and post-retention study models of 30 subjects with a Class II division 2 malocclusion were assessed, after a period of at least 3 years, in order to evaluate the long-term changes in occlusion, alignment, and arch dimensions. Molar relationship correction was found to be stable after retention. There were no variables which could be used to establish a prognosis of vertical stability. Over-correction of overbite was seen to relapse. Ten per cent of the cases showed unacceptable anterior maxillary irregularities after retention. Mandibular arch width and length usually showed a decrease after retention. An increase in lower intercanine width and arch length achieved by orthodontic treatment always relapsed. This relapse was associated with post-retention mandibular irregularity and crowding. Nine cases (30 per cent) showed an unacceptable degree of mandibular irregularity after retention. Pre-treatment crowding in the mandible showed a relationship with post-retention lower irregularity and crowding. There was a correlation between the number of years which had elapsed after retention, overbite relapse and post-retention mandibular irregularity.

Adolescent↗
PubMed1996

PI locus (alpha-1-antitrypsin) allelic frequencies in an Andean Venezuelan population.

PI phenotypes were determined by isolelectric focusing in a Venezuelan mixed population (the center point of the geographical area investigated being Apartaderos, State of Mérida, Venezuela). Six alleles were found, four normal and two risk-predisposing with the following frequencies: PI*M1 (80.5%), PI*M2 (7.0%), PI*M3 (6.2%), an anodic allele here referred to as PI*"AN' (0.2%), PI*S (5.0%) and PI*Z (0.9%). The latter, unlike the others, was found only in 10% of the area considered, where it had a polymorphic frequency of 2.1%, reflecting a probable geographic isolation and/or a cultural influence in mating choice. In this population the alleles predisposing to risk are most probably of Caucasoid origin ("Spanish' genes). The PI*Z and PI*S frequencies may be attributed to random genetic drift characterized by an important founder phenomenon and to population admixture (Amerindian and Spanish), respectively. The PI*S allele may be considered a very good marker for the Caucasoid contribution to the overall mixed population of Venezuela.

Adolescent↗
PubMed1994

Safety, immunogenicity and protective effect of the SPf66 malaria synthetic vaccine against Plasmodium falciparum infection in a randomized double-blind placebo-controlled field trial in an endemic area of Ecuador.

A total of 537 subjects were randomized to receive either SPf66 malaria vaccine against Plasmodium falciparum or placebo in three doses (days 0, 30 and 180). Subjects completing the course of vaccination (230 in the vaccine and 238 in the placebo group) were followed up for a further 12 months. Case detection surveillance was implemented by parasitological cross-sectional surveys every 2 months and by monthly household visits to each participant. Symptomatic subjects were also diagnosed in a local health centre. Minor local side-effects were observed mainly after the second dose in about 19% of the vaccinated subjects and in 3.7% of the placebo group. Thirty days after the third dose the prevalence of anti-SPf66 antibodies was 57% in the vaccine and 8.8% in the placebo groups. The prevaccination prevalence of antibodies measured by indirect immunofluorescence assay increased with age and seemed to be inversely related to anti-SPf66 antibody production. Immune response to SPf66 was independent of age. Vaccine efficacy was calculated based on person-time of exposure. The protective effect considering any malaria episode was 66.8% (95% confidence interval = -2.7-89.3%) and considering only one episode per individual was 60.2% (95% confidence interval = -26-87.5%).

Adolescent↗
PubMed1987

Sharing of MHC haplotypes among apparently unrelated patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

From the study of HLA, complement, and glyoxalase I alleles in 82 Venezuelan individuals belonging to 19 families of mixed ethnic origin having 20 affected newborns with salt-wasting congenital adrenal hyperplasia due to 21-hydroxylase (21-OH) deficiency, a total of 38 disease haplotypes and 53 nondisease haplotypes were found. Of the pathological haplotypes 47% were found to share the HLA-B39 or -Bw62 specificities, 55% of them in combination with the BFS, C2C, C4A4, C4B2 (SC42) complotype. The frequencies of HLA-B39 and -Bw62 among the affected haplotypes were 29 and 18% as compared with 6 and 0% among the nondisease haplotypes of the same families. Statistical associations (P less than 0.01) with salt-wasting adrenal hyperplasia were found with the SC42 complotype and with the combination SC42, HLA-B39. These results are markedly different from those reported in the literature which show an "association" at the population level among many Caucasoid samples of HLA-Bw47 and the extended haplotype (HLA-Bw47, DR7,FC91,0) with the salt-wasting form of the disease. Furthermore, four of the unrelated patients reported here were homozygous for all the major histocompatibility complex loci tested, while three others were homozygous for at least two HLA loci. Analysis of the geographical origin of the grandparents indicated clustering of the deficiency carrier HLA haplotypes. This observation, together with the fact that there is an excess of homozygotes among the patients in Venezuela, strongly suggests that salt-wasting 21-OH deficiency congenital adrenal hyperplasia is mostly the result of a founder effect of relatively hyperplasia is mostly the result of a founder effect identity by descent of a few abnormal alleles at the 21-OHB locus in most cases. The mutation marked by HLA-Bw47 was not observed in this population.

Adrenal Hyperplasia, Congenital↗
PubMed1980

The IVIC syndrome: a new autosomal dominant complex pleiotropic syndrome with radial ray hypoplasia, hearing impairment, external ophthalmoplegia, and thrombocytopenia.

The IVIC syndrome is an autosomal dominant condition affecting mainly the upper limbs. It is described from 19 living members of one family of mostly Caucasoid descent; it came to Venezuela from the Canary Islands 140 years ago. The new mutation appeared six generations ago. It has complete penetrance and wide expressivity for a radial ray defect which may vary from an almost normal thumb to a severely malformed upper limb. When present, the thumb has a long/slender metacarpal and a short distal phalanx, reflected in a typical metacarpophalangeal (MP) pattern profile. Anthropometry reveals delayed growth in the forearms, clavicles, and cranium during adolescence, and permanently in the spine; the maturation of the face, tibiae, and feet is normal. The radial carpal bones are always affected, some being still hypoplastic at advanced ages. Constant palmar dermatoglyphic anomalies are a high a-b ridge count, a distally placed or absent t triradius, and an increased frequency of patterns in the second interdigital area. Extraocular muscles are involved almost always, producing strabismus. Hearing is bilaterally impaired due to a mixed congenital loss, either total or partial. Mild thrombocytopenia and leukocytosis are present before the age of 50 years. There is neither associated ectodermal dysplasia nor heart involvement [except for occasional mild, incomplete right bundle branch block (IRBBB)]; imperforate anus occurs in about 10% of affected persons. The possible pathogenetic relationship to the thalidomide embryopathy and to the Holt-Oram syndrome, among others, is discussed.

Adolescent↗