Angélica Muñoz

Basal slip in sapphire (α-Al2O3)

Abstract Plastic deformation of sapphire has been performed along three different compression axes to activate (0001) basal slip along one or two 〈20〉 directions. One of the orientations is identical to that used in earlier experiments, with the activation of one glide direction, or Burgers vector. We also investigated two new orientations which permit activation of two Burgers vectors. We have shown that for one of these orientations, rhombohedral twinning is difficult to activate and large deformations, for unpolished specimens, can be reached by basal slip down to 900°C. Basal glide along 〈010〉 was observed; the yield stress values are the same for 〈010〉 and

Las manifestaciones analíticas asociadas a la insuficiencia renal crónica: a partir de qué grado de filtrado glomerular estimado las detectamos en ancianos?

OBJECTIVE A classification of chronic kidney disease (CKD) based on stages of glomerular filtration (GF) has recently been developed. Thus, chronic renal failure (CRF) is based on GF <60 ml/min. Our goal was to study the presence of typical manifestations of CRF in elderly individuals with a GF of <60 ml/min (stage 3-5) and to determine the cut-off value at which GF can be used to detect these manifestations. MATERIAL AND METHODS We performed a cross-sectional study in clinically-stable elderly patients attending the geriatrics and nephrology outpatient department. The estimated GF (GFe) was established with the Cockroft-Gault and abbreviated Modification of Diet in Renal Disease Study (MDRD) formulae. Because these patients had a GF of less than 60 ml/min, they were expected to show the manifestations associated with CRF (anaemia, metabolic acidosis, abnormal bone and mineral metabolism). We evaluated the occurrence of these manifestations and the GF cut-off at which they were detected. To do this, the population was divided into two groups: group A: patients with GFe > or = 30 ml/min (stage 3, N=48); and group B: patients with GFe <30 ml/min (stages 4-5, N=8). RESULTS Seventy percent of the patients had a GFe (MDRD) <60 ml/min (stage 3-5). Despite reduced GF, these patients did not show the typical manifestations of CRF. Group B showed higher plasmatic levels of creatinine, urea, uric acid, and potassium and required treatment with erythropoietin and calcium salts. CONCLUSIONS Many elderly people diagnosed with CKD with the current classification do not show manifestations of CRF. Estimation of the GF in elders should be generalized to correctly adjust medication to renal impairment rather than to classify elders into CKD stage.

Thyroid Function Tests and Mortality in Aged Hospitalized Patients: A 7-Year Prospective Observational Study

CONTEXT Several alterations in thyroid function test (TFT) results have been associated with mortality in elderly patients. OBJECTIVE Our aim was to investigate the relationship between TFT results and all-cause and cardiovascular (CV) mortality in aged hospitalized patients. DESIGN A 7-year prospective observational study was conducted. TFTs were performed at hospital admission, and mortality was registered in the follow-up period. PATIENTS Participants were 404 patients aged >65 years admitted to the Department of Geriatrics, Hospital General, Segovia, Spain, for any reason during 2005. MAIN OUTCOME MEASURES The study evaluated the association between TFT results and mortality from all causes and CV diseases. METHODS TSH, free T₄, and free T₃ (FT₃) were measured on the first day of admission. In-hospital and total survival times, number of deaths, and all-cause and CV mortality were registered until the census date on January 1, 2012. RESULTS During the study, 323 patients (80%) died. Kaplan-Meier analysis showed that median survival time for all-cause mortality was significantly lower in patients in the first tertile of serum FT₃, in the first tertile of TSH, and in the first tertile of serum free T₄ concentrations. Multivariate adjusted Cox regression analysis showed that the history of cancer (hazard ratio, 1.60; 95% confidence interval, 1.12-2.28; P = .009), age (1.03; 1.01-1.06; P = .003), and FT₃ levels (0.72; 0.63-0.84; P < .001) were significant factors related to all-cause mortality. The cause of death was known in 202 patients. Of this group, 61 patients (30.2%) died of CV disease. Patients in the first tertile of TSH and FT₃ exhibited a significant higher mortality due to CV disease. In the adjusted Cox regression analysis, FT₃ was a significant predictor of CV mortality (0.76; 0.63-0.91; P = .004). CONCLUSIONS Alterations in TFT results during hospitalization are associated with long-term mortality in elderly patients. In particular, low FT₃ levels are significantly related to all-cause and CV mortality.

Fasting hyperglycaemia and in-hospital mortality in elderly population

Background:  Admission hyperglycaemia has shown to be a marker of poor clinical outcome. The prevalence of admission hyperglycaemia and its relationship with in‐hospital mortality in elderly population has not been clearly defined. We assessed the prevalence and prognostic significance of admission fasting hyperglycaemia in aged patients.

Estimacion del filtrado glomerular en personas de 69 anos o mas: concordancia entre diferentes metodos de calculo

MATERIAL Estimation of glomerular filtration rate (eGFR) is the most widely accepted marker of renal function. Precise calculation is not routinely performed in clinical practice. Several methods have been developed for eGFR: creatinine clearance (CCr) calculation or the use of formulae derived from serum creatinine (sCr). The present study aimed to analyze the agreement between distinct methods of calculating eGFR. MATERIAL AND METHODS We performed a cross-sectional study between January and April, 2006 in 32 stable elders, aged 69 years or older, evaluated in a general nephrology unit. eGFR was calculated by CCr (considered the gold standard), Cockcroft-Gault (CG) and Modification of Renal Diet in Disease (MDRD) equations. The Mann Whitney U-test, Spearmans correlation coefficient and the Kappa coefficient were used to compare means and determine the concordance between methods. RESULTS The overall means+/-SD of GFRe for CCr were 36.14+/-16 ml/min (range 11.75-69.6); CG: 37.02+/-16 ml/min (range 13.3-72.3) and MDRD: 45.52+/-16 ml/min (range 19.2-75.36). Variations in eGFR on comparison of methods were CCr and MDRD: -9.37 ml/min (95% CI:-13.85, -4.9); CCr and CG:-2.54 ml/min (95% CI: -6.95, 1.80); MDRD and CG: 9.0 ml/min (95% CI: 5.96, 12). The correlation between the gold standard (CCr) and sCr-derived formulae was r=0.74 for MDRD (P<0.001) and r=0.77 for CG (P<0.001). The Kappa value for CCr and CG was 0.44 and was 0.35 for CCr and MDRD. When patients were classified by stage of chronic renal disease, discrepancies were found according to the method used: stage 5 (eGFR<15 ml/min) was diagnosed in 13.63% with CG while none were diagnosed with stage 5 with MDRD. CONCLUSIONS In the estimation of the renal function in the elderly, eGFRe levels can differ in the same patient according to the method used: in view of the degree of concordance between CG and CCr, this mathematical formula should be used in preference to MDRD.

Serum thyrotropin concentration is an early marker of normalization of low triiodothyronine syndrome in aged hospitalized patients after discharge.

Objectives: To assess short-term spontaneous evolution of alterations in thyroid function tests in aged hospitalized patients after discharge. Methods: A group of 146 patients (mean age±SD 85.9±6.2 yr) was studied. Serum concentrations of TSH, free T4 (FT4), and free T3 (FT3) were evaluated in every patient both after admission and 1 month after discharge. Results: At entry, both serum TSH [median (interquartile range), 2.19 mU/l (0.89–2.31)] and FT4 (mean±SD, 16.7±3.4 pmol/l) concentrations were into the normal range, whereas serum FT3 concentrations were low (3.3±0.7 pmol/l). After discharge TSH and FT4 concentrations remained normal and FT3 low. However, both serum TSH [2.53 mU/l (1.24–3.33); p<0.01] and FT3 (3.7±1.0 pmol/l; p*#x003C;0.001) concentrations significantly increased. Most patients (no.=124, 84.9%) showed the euthyroid sick syndrome (ESS). After discharge, ESS diminished to 76 (52.1%) subjects. Patients who normalized thyroid function tests showed significantly lower TSH values at entry compared with those who persisted with altered thyroid function tests [1.27 mU/l (0.69–1.89) vs 1.69 mU/l (0.96–2.91), p<0.05]. Logistic regression analysis showed that serum levels of TSH at admission was the only variable negatively related to normalization of thyroid function [odds ratio 0.730; confidence interval 95%, 0.567–0.940; p=0.01). Conclusions: About 35% of aged patients hospitalized for acute illness spontaneously normalize their thyroid function tests 1 month after discharge, mainly due to the correction of ESS. Serum TSH levels at admission seem to be the only variable negatively related to normalization of thyroid function at this time.