Narrowing the Parameter Space of Collapse Models with Ultracold Layered Force Sensors.

Despite the unquestionable empirical success of quantum theory, witnessed by the recent uprising of quantum technologies, the debate on how to reconcile the theory with the macroscopic classical world is still open. Spontaneous collapse models are one of the few testable solutions so far proposed. In particular, the continuous spontaneous localization (CSL) model has become subject of intense experimental research. Experiments looking for the universal force noise predicted by CSL in ultrasensitive mechanical resonators have recently set the strongest unambiguous bounds on CSL. Further improving these experiments by direct reduction of mechanical noise is technically challenging. Here, we implement a recently proposed alternative strategy that aims at enhancing the CSL noise by exploiting a multilayer test mass attached on a high quality factor microcantilever. The test mass is specifically designed to enhance the effect of CSL noise at the characteristic length r_{c}=10^{-7} m. The measurements are in good agreement with pure thermal motion for temperatures down to 100 mK. From the absence of excess noise, we infer a new bound on the collapse rate at the characteristic length r_{c}=10^{-7} m, which improves over previous mechanical experiments by more than 1 order of magnitude. Our results explicitly challenge a well-motivated region of the CSL parameter space proposed by Adler.

[Reliability of the measurement of glucose at the bedside of critical patients]. / Fiabilidad de la determinación de la glucemia a la cabecera del paciente en pacientes críticos.

INTRODUCTION: The objective of this study is to measure the reliability of three measurement methods at the bedside of the patient, of glucose in the critical patient compared with the measurement of glucose in the central laboratory. MATERIAL AND METHODS: Observational, perspective study developed in a polyvalent unit of 18 beds for four months. Patients who had arterial catheter were included. Eight samples obtained at the patient's bedside were compared with the plasma glucose (gold Standard): three in capillary blood, four in arterial blood and one in arterial blood gases from a syringe. The measurements at bedside were conducted with reactive strips MediSense Optium Plus and glucometer MediSense Optium. A comparison was made of the means used in the Student's T test and Bland and Altman analysis. RESULTS: We obtained 630 samples in 70 patients. Mean glucose (SD) in mg/dl was: a) capillary samples: 149 (38), 149 (35), 147 (37); b) arterial samples: 140 (34), 142 (35), 143 (35), 142 (34); arterial gas sample syringe: 143 (33); c) plasma glucose: 138(33). There were significant differences (p < 0.001) between plasma glucose and capillary samples but not with arterial samples (p=0.2). In the arterial samples, the presence of some factors, such as vasoactive drugs, glycated solution perfusion, insulin perfusion and plasma concentration of hemoglobin, increase error and dispersion regarding the gold standard. CONCLUSIONS: The measurement of glucose at bedside in critical patients is more reliable in arterial samples than in capillary ones.

Fiabilidad de la determinación de la glucemia a la cabecera del paciente en pacientes críticos / Reliability of the measurement of glucose at the bedside of critical patients

Introducción. El objetivo de este estudio es determinar la fiabilidad de tres métodos de determinación, a pie de cama, de la glucemia en el paciente crítico comparados con la determinación de glucemia en el laboratorio central. Material y métodos. Estudio observacional prospectivo desarrollado en una Unidad polivalente de 18 camas durante 4 meses. Se incluyeron pacientes que portaban catéter arterial. Se compararon con la glucemia plasmática (patrón oro) 8 muestras obtenidas a la cabecera del paciente: tres en sangre capilar, 4 en sangre arterial y una de sangre arterial en jeringa de gases. Las determinaciones a la cabecera fueron realizadas con tiras reactivas MediSense® Optium™ Plus y glucómetro MediSense® Optium™. Se realizó una comparación de medias mediante la prueba de la «t» de Student y análisis de Bland y Altman. Resultados. Obtuvimos 630 muestras en 70 pacientes. La glucemia media (desviación estándar [DE]) en mg/dl fue: a) muestras capilares: 149 (38), 149 (35), 147 (37); b) muestras arteriales: 140(34), 142 (35), 143 (35), 142 (34); muestra arterial en jeringa de gases: 143 (33); c) glucemia plasmática: 138 (33). Hubo diferencias significativas (p < 0,001) entre la glucemia plasmática y las muestras capilares, pero no con las muestras arteriales (p = 0,2). En las muestras arteriales la presencia de algunos factores, como fármacos vasoactivos, perfusión de soluciones glucosadas, perfusión de insulina y concentración plasmática de hemoglobina, aumenta el error y la dispersión respecto al patrón oro. Conclusiones. En enfermos críticos la medida de la glucemia a pie de cama es más fiable en muestras arteriales que en muestras capilares

Introduction. The objective of this study is to measure the reliability of three measurement methods at the bedside of the patient, of glucose in the critical patient compared with the measurement of glucose in the central laboratory. Material and methods. Observational, perspective study developed in a polyvalent unit of 18 beds for four months. Patients who had arterial catheter were included. Eight samples obtained at the patient's bedside were compared with the plasma glucose (gold Standard): three in capillary blood, four in arterial blood and one in arterial blood gases from a syringe. The measurements at bedside were conducted with reactive strips MediSense® Optium™ Plus and glucometer MediSense® Optium™. A comparison was made of the means used in the Student's T test and Bland and Altman analysis. Results. We obtained 630 samples in 70 patients. Mean glucose (SD) in mg/dl was: a) capillary samples: 149 (38), 149 (35), 147 (37); b) arterial samples: 140 (34), 142 (35), 143 (35), 142 (34); arterial gas sample syringe: 143 (33); c) plasma glucose: 138(33). There were significant differences (p < 0.001) between plasma glucose and capillary samples but not with arterial samples (p=0.2). In the arterial samples, the presence of some factors, such as vasoactive drugs, glycated solution perfusion, insulin perfusion and plasma concentration of hemoglobin, increase error and dispersion regarding the gold standard. Conclusions. The measurement of glucose at bedside in critical patients is more reliable in arterial samples than in capillary ones

Hyperthyroidism and production of precocious involution in the mammary glands of lactating rats.

This study investigated the influence of chronic hyperthyroidism on mammary function in lactating rats and the effects on their pups. Thyroxine-treated (10 microg per 100 g body weight per day; hyperthyroid (HT)) or vehicle-treated rats were mated 2 weeks after the start of treatment and killed with their litters on days 7, 14 and 21 of lactation. Serum concentrations of triiodothyronine (T(3)) and tetraiodothyronine (T(4)) increased in thyroxine-treated rats. In HT mothers, serum prolactin decreased on day 7 and day 14 of lactation, whereas insulin-like growth factor I (IGF-I) and progesterone concentrations decreased, and corticosterone increased on day 7 of lactation. In HT pups, T(4) concentration increased on day 7 and day 14 of lactation, whereas T(3) increased only on day 14 of lactation, and growth hormone increased on day 7 of lactation. Mammary prolactin binding sites did not vary, but there was an increase in the binding sites in the liver on day 14 of lactation in thyroxine-treated rats. In an acute suckling experiment, thyroxine-treated rats released less oxytocin, growth hormone and prolactin and excreted less milk than did control rats. Mammary casein, lactose and total lipid concentrations in thyroxine-treated rats were similar to those of control rats on day 14 of lactation. Histological studies of the mammary glands showed an increased proportion of alveoli showing reduced or no lumina and cells with condensed nuclei on day 14 and day 21 of lactation; the TdT-mediated dUTP nick-end labelling (TUNEL) test revealed an increase in apoptosis in alveolar cells on day 21 of lactation in thyroxine-treated rats. Expression of SGP-2, a gene expressed during mammary involution, increased in thyroxine-treated rats on day 14 and day 21 of lactation, whereas expression of insulin-like growth factor binding protein 5, a proapoptotic signal, was unchanged. Bcl-2, which promotes survival of mammary gland epithelial cells was unchanged, whereas expression of IGF-I, which also promotes survival of mammary gland epithelial cells, increased on day 21 of lactation in thyroxine-treated rats. These results indicate that thyroxine treatment produces some milk stasis as a result of impairments in suckling induced release of oxytocin that may initiate the first stage of mammary involution, increasing apoptosis in a gland that is otherwise actively producing and secreting milk.

Hyperthyroidism affects lipid metabolism in lactating and suckling rats.

Two per thousand pregnant women have hyperthyroidism (HT), and although the symptoms are attenuated during pregnancy, they rebound after delivery, affecting infant development. To examine the effects of hyperthyroidism on lactation, we studied lipid metabolism in maternal mammary glands and livers of hyperthyroid rats and their pups. Thyroxine (10 microg/100 g body weight/d) or vehicle-treated rats were made pregnant 2 wk after commencement of treatment and sacrificed on days 7, 14, and 21 of lactation with the litters. Circulating triiodothyronine and tetraiodothyronine concentrations in the HT mothers were increased on all days. Hepatic esterified cholesterol (EC) and free cholesterol (FC) and triglyceride (TG) concentrations were diminished on days 14 and 21. Lipid synthesis, measured by incorporation of [3H]H2O into EC, FC, and TG, fatty acid synthase, and acetyl CoA carboxylase activities increased at day 14, while incorporation into FC and EC decreased at days 7 and 21, respectively. Mammary FC and TG concentrations were diminished at day 14; incorporation of [3H]H2O into TG decreased at days 7 and 21, and incorporation of [3H]H2O into FC increased at day 14. In the HT pups, growth rate was diminished, tetraiodothyronine concentration rose at days 7 and 14 of lactation, and triiodothyronine increased only at day 14. Liver TG concentrations increased at day 7 and fell at day 14, while FC increased at day 14 and only acetyl CoA carboxylase activity fell at day 14. Thus, hyperthyroidism changed maternal liver and mammary lipid metabolism, with decreased lipid concentration in spite of increased liver rate of synthesis and decreases in mammary synthesis. These changes, along with the mild hyperthyroidism of the litters, may have contributed to their reduced growth rate.

Lipids in rat liver submitted to acute and chronic hyperthyroidism.

The effect of acute and chronic hyperthyroidism was studied in serum and liver lipids in rats. Wistar adult female rats were separated into three groups. The first group, injected with saline solution was used as control (Co), while the second and third were injected daily with tetraiodothyronine (T4) 10 microg/100 g body weight; the second group (HT-I) for one week and the third group (HT-II) for five weeks. In HT-I, serum T4 level was higher than in HT-II. Triiodothyronine (T3) concentration increased in HT-I and HT-II. The serum triglyceride concentration increased in HT-II in relation to HT-I and Co groups. Serum total cholesterol, HDL-cholesterol and bile acids did not vary among the three groups. LDL cholesterol fraction was lower in HT-I and HT-II than in Co group. In the liver, total and free cholesterol (FC) concentrations decreased in HT-I, but both increased in HT-II, in relation to Co. Esterified cholesterol did not change among the three groups. Liver triglyceride (TG) mass decreased in HT-I and HT-II in relation to Co, but it was higher in HT-II than in HT-I. Hepatic fatty-acid synthase (FAS) and acetyl-CoA carboxylase (ACC) activities increased in HT-I and HT-II in relation to Co and there were no differences between HT-I and HT-II. The incorporation of [3H]-H2O into esterified cholesterol did not differ significantly among the groups, while its incorporation into FC decreased and into TG increased in HT-I and HT-II, in relation to Co. The effect of T4 on the amount and turnover of lipids is affected by the time of hormone administration, but the increase of FAS and ACC activities was the same for both times studied.

[Determination of plasma levels of phenytoin. Evaluation of 2 techniques]. / Determinación de níveles plasmáticos de fenitoina. Evaluación de dos técnicas analíticas.

We compared 2 techniques for determination of plasma levels of phenytoin, liquid-gas chromatography (LGC) and homogeneous enzymatic immunoassay (EI) in samples from 72 patients receiving monotherapy with this drug. Determinations were also made in samples of normal plasma with known concentrations of phenytoin. Good correlation of both techniques was observed in patient samples containing less than 15 micrograms/ml of the drug but not with higher concentrations. LGC was accurate in determination of known concentrations of phenytoin, whereas immunoassay showed an exponential deviation with overestimation of phenytoin levels. Thus LGC is a better technique for determination of phenytoin levels; however EI may be used in most clinical situations when the concentration of phenytoin lies under 20 micrograms/dl.