The diagnostic value of Gram stain for initial identification of the etiologic agent of peritonitis in CAPD patients

Objective: To evaluate the effectiveness of the Gram stain in the initial diagnosis of the etiologic agent of peritonitis in continuous ambulatory peritoneal dialysis (CAPD). Design: Retrospective study analyzing the sensitivity (S), specificity (SS), positive predictive value (+PV), and negative predictive value (-PV) of the Gram stain relating to the results of cultures in 149 episodes of peritonitis in CAPD. The data were analyzed in two studies. In the first, only the cases with detection of a single agent by Gram stain were taken (Study 1). In the second, only the cases with two agents in Gram stain were evaluated (Study 2). Setting: Dialysis Unit and Laboratory of Microbiology of a tertiary medical center. Patients: Sixty-three patients on regular CAPD who presented one or more episodes of peritonitis from May 1992 to May 1995. Results: The positivity of Gram stain was 93.2% and the sensitivity was 95.7%. The values of S, SS, +PV, and -PV were respectively: 94.9%, 53.5%, 68.3%, and 90.9% for gram-positive cocci and 83.3%, 98.8%, 95.2%, and 95.6% for gram-negative bacilli. The association of gram-positive cocci plus gram-negative bacilli were predictive of growth of both in 6.8%, growth of gram-positive cocci in 13.7%, and growth of gram-negative bacilli in 72.5%. Conclusions: The Gram stain is a method of great value in the initial diagnosis of the etiologic agent of peritonitis in CAPD, especially for gram-negative bacilli

Myocardial contractile dysfunction contributes to the development of heart failure in rats with aortic stenosis

Objectives: To analyze the potential contribution of contractility state and ventricular geometry to the development of heart failure in rats with aortic stenosis.Methods: Rats were divided into three groups: compensated aortic stenosis (AS, n = 11), heart failure AS (n = 12) and control rats (C, n = 13).Results: After 21 weeks, failing AS rats presented higher systolic (C = 36.6 +/- 3.1, AS-78.6 +/- 4.8*, failing AS = 104.6 +/- 7.8*) and diastolic meridian stress (C = 6.9 +/- 0.4, AS = 20.1 +/- 1.1*, failing AS = 43.2 +/- 3.2*(dagger)), hydroxyproline (C = 3.6 +/- 0.7 mg/g, AS = 6.6 +/- 0.6* mg/g, failing AS = 9.2 +/- 1.4*(dagger) mg/g) and cross-sectional area (C = 338 +/- 25 mu m(2), AS = 451 +/- 32* mu m(2), failing AS = 508 +/- 36*(dagger) mu m(2)), in comparison with control and compensated AS animals (*p < 0.05 vs. control, (dagger)p < 0.05 vs. AS). In the isometric contraction study, considering the time from peak tension to 50% relaxation (RT50), the relative variation responses, following post-rest contraction and increase in Ca2+ concentration, were higher in failing AS than compensated AS animals. In contrast, following post-rest contraction, compensated AS group presented higher values of the peak developed tension (DT) than failing AS group. Following beta-adrenergic stimulation, control animals presented higher values of +dT/dt and -dT/dt than AS animals. In addition, failing AS animals presented higher TPT values than compensated AS animals.Conclusion: Myocardial contractile dysfunction contributes to the development of heart failure in rats with aortic stenosis. (c) 2006 Elsevier B.V.. All rights reserved

Down-regulation of MyoD gene expression in rat diaphragm muscle with heart failure

Diaphragm myopathy has been described in patients with heart failure (HF), with alterations in myosin heavy chains (MHC) expression. The pathways that regulate MHC expression during HF have not been described, and myogenic regulatory factors (MRFs) may be involved. The purpose of this investigation was to determine MRF mRNA expression levels in the diaphragm. Diaphragm muscle from both HF and control Wistar rats was studied when overt HF had developed, 22 days after monocrotaline administration. MyoD, myogenin and MRF4 gene expression were determined by RT-PCR and MHC isoforms by polyacrylamide gel electrophoresis. Heart failure animals presented decreased MHC IIa/IIx protein isoform and MyoD gene expression, without altering MHC I, IIb, myogenin and MRF4. Our results show that in HF, MyoD is selectively down-regulated, which might be associated with alterations in MHC IIa/IIx content. These changes are likely to contribute to the diaphragm myopathy caused by HF

Sistema sensor autònom sense fils de baix consum per al control d'il·luminació i reg en cultius d'hivernacle

The project aims to implement a system of irrigation and lighting control for a greenhouse. To perform such control, the system must sensors to measure various parameters such as ambient temperature, relative humidity, ground humidity and light intensity. Once measured these values, the sensor system must send orders for the different actuators and also send ,via Wireless, these data to our Labview application to be displayed on the screen and be able to study these parameters based on time. The sensor system must be performed with a low power microcontroller PIC18 for the system to be autonomous with little energy supply. The PIC will be programmed in C using the FSM style programming. The first programs will be simulated in the virtual simulator Proteus to detect bugs more effectively. After performing the simulations, the program will be loaded into our physical PIC on our testboard where we find that everything works as we simulated. In choosing sensors, it will try to work with either analog and digital sensors. Regarding the sensors with digital interface, it is important to conduct a study of its communication protocols. Finally, after making the final prototype in our testboard, our printed circuit board (PCB) of our sensor system will be designed with Eagle and, if possible, the machining of the PCB will be done as well