Tehran University of Medical Sciences

About: Tehran University of Medical Sciences is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Population & Medicine. The organization has 35661 authors who have published 57234 publications receiving 878523 citations. The organization is also known as: TUMS.

Separation in Logistic Regression: Causes, Consequences, and Control.

Abstract: Separation is encountered in regression models with a discrete outcome (such as logistic regression) where the covariates perfectly predict the outcome. It is most frequent under the same conditions that lead to small-sample and sparse-data bias, such as presence of a rare outcome, rare exposures, highly correlated covariates, or covariates with strong effects. In theory, separation will produce infinite estimates for some coefficients. In practice, however, separation may be unnoticed or mishandled because of software limits in recognizing and handling the problem and in notifying the user. We discuss causes of separation in logistic regression and describe how common software packages deal with it. We then describe methods that remove separation, focusing on the same penalized-likelihood techniques used to address more general sparse-data problems. These methods improve accuracy, avoid software problems, and allow interpretation as Bayesian analyses with weakly informative priors. We discuss likelihood penalties, including some that can be implemented easily with any software package, and their relative advantages and disadvantages. We provide an illustration of ideas and methods using data from a case-control study of contraceptive practices and urinary tract infection.

Communication Barriers Perceived by Nurses and Patients

Abstract: Communication, as a key element in providing high-quality health care services, leads to patient satisfaction and health. The present Cross sectional, descriptive analytic study was conducted on 70 nurses and 50 patients in two hospitals affiliated to Alborz University of Medical Sciences, in 2012. Two separate questionnaires were used for nurses and patients, and the reliability and validity of the questionnaires were assessed. In both groups of nurses and patients, nurse-related factors (mean scores of 2.45 and 2.15, respectively) and common factors between nurses and patients (mean scores of 1.85 and 1.96, respectively) were considered the most and least significant factors, respectively. Also, a significant difference was observed between the mean scores of nurses and patients regarding patient-related (p=0.001), nurse-related (p=0.012), and environmental factors (p=0.019). Despite the attention of nurses and patients to communication, there are some barriers, which can be removed through raising the awareness of nurses and patients along with creating a desirable environment. We recommend that nurses be effectively trained in communication skills and be encouraged by constant monitoring of the obtained skills.

Efficiency removal of phenol, lead and cadmium by means of uv/tio2/h2o2 processes

Abstract: A variety of processes can be used in treatment of industrial wastewaters. The relatively newest of which is photo catalysis with titanium dioxide which may also be used plus hydrogen peroxide to improve the treatment rate. In this study, photo catalysis/ hydrogen peroxide processes had been employed for the removal of phenol, lead and cadmium by three different pHs of 3.5, 7 and 11. The treatment tests were also accomplished without UV irradiation. In both experiments, the variables were pH and concentrations of reagent chemicals, but the detention time was kept constant (180 min). Results indicated that the optimum efficiencies of phenol and Cd removal were 76 % and 97.7 % at pH=11, respectively, and for lead, it was 98.8% in all pHs. In other words, no pH dependency was regarded for lead treatment. These results were all obtained by simultaneous use of UV irradiation with 3 mL/L H2O2 and 0.8 g/L TiO2. Finally, the best pH for treatment, when all the three contaminants are presented is considered to be at 11. These results should be regarded by all industrial treatment plants which have experienced the problem of these three special contaminants in their effluents.

Randomized placebo-controlled trial of mesenchymal stem cell transplantation in decompensated cirrhosis

Abstract: Background & Aims There has been great interest in recent years to take advantage of bone marrow stem cells to treat cirrhosis. Our uncontrolled trial showed promising results for bone marrow mesenchymal stem cell (MSC) transplantation in cirrhosis. Therefore, we conducted a randomized, placebo-controlled trial to evaluate the efficacy of autologous MSC transplantation in cirrhosis. Methods The enrolled patients with decompensated cirrhosis were randomly assigned to receive MSC or placebo infusions. A median of 195 million (range: 120–295 million) cultured MSCs were infused through a peripheral vein. The primary outcome was absolute changes in MELD score. Secondary outcomes were absolute changes in Child score, liver function tests and liver volumes between the MSC and placebo group 12 months after infusion. Results A total of 27 patients were enrolled. Of these, 15 patients received MSC and 12 patients received placebo. One patient in the MSC group and one patient in the placebo group were lost to follow-up. Three patients in the MSC group died of liver failure 3 months (one patient), or 5 months (two patients) after cellular infusion. The baseline MELD scores of the deceased patients were significantly higher than those who remained alive in either group (20.0 vs. 15.1; P = 0.02). The absolute changes in Child scores, MELD scores, serum albumin, INR, serum transaminases and liver volumes did not differ significantly between the MSC and placebo groups at 12 months of follow-up. Conclusion Based on this randomized controlled trial, autologous bone marrow MSC transplantation through peripheral vein probably has no beneficial effect in cirrhotic patients. Further studies with higher number of patients are warranted to better clarify the impact of MSC infusion through peripheral vein or portal vein in cirrhosis.

The importance of hypoglycemia in diabetic patients

Abstract: Hypoglycemia is one of the most important complications of diabetes treatment. The risk of severe hypoglycemia is higher in elderly patients, those having comorbidities such as vascular disease or renal failure, pregnant women and in children with type 1diabetes. Moreover, in type 2 diabetes, progressive insulin deficiency, longer duration of diabetes, and tight glycemic control increase the risk of hypoglycemia as much as type 1 diabetes.Episodes hypoglycemia may lead to impairment of counter-regulatory system, with the potential of development of hypoglycemia unawareness. So, hypoglycemia may increase the vascular events even death in addition to other possible detrimental effects. Glycemic control should be individualized based on patient characteristics with some degree of safety. Recognition of hypoglycemia risk factors, blood glucose monitoring, selection of appropriate regimens and educational programs for healthcare professionals and patients with diabetes are the major issues to maintain good glycemic control, minimize the risk of hypoglycemia, and prevent long- term complications.