Peak bone mass of Iranian population: the Iranian Multicenter Osteoporosis Study.

Osteoporosis is a major public health problem in the Western countries and is projected to have a similar impact in the Middle East. It has been suggested that peak bone mineral density (BMD), a major determinant of osteoporotic fractures later in life, may be lower in this part of the world compared with the Western world. The purpose of the Iranian Multicenter Osteoporosis Study was to determine peak bone mass in a randomly chosen sample of healthy Iranian subjects. A total of 5201 participants (2340 males, mean age 42.7+/-13.8) were recruited based on randomized clustered sampling from all regions of five major cities across the country. In women, peak lumbar BMD (1.182+/-0.127 g/cm2) occurred in the 29- to 33-yr age group, whereas peak total femur BMD (1.006+/-0.126 g/cm2) occurred in the 32- to 36-yr age group. In men, peak lumbar BMD (1.181+/-0.153 g/cm2) and femoral BMD (1.096+/-0.159 g/cm2) both occurred in the 20- to 24-yr age group. When standardized to mg/cm2 units using established formulas, Iranian peak bone mass values are comparable with that of Western countries and are generally higher than that of Eastern Asian and Middle Eastern countries.     

The effect of applied pressure on the electrical impedance of the bladder tissue using small and large probes

There are a number of studies using electrical impedance spectroscopy, a minimally invasive technique, as a tissue characterizing method with different probe sizes (usually with larger probe diameters than that used in this work). In urinary bladder studies the probe size are limited to 2 mm diameter, in order to pass through the working channel of the cystoscope to measure the impedance inside the urinary bladder. Thus, bio-impedance of the human urothelium can only be measured using a small sized probe for in vivo studies. Different pressures were applied with this probe and it was demonstrated that increasing the applied pressure over the probe would increase the measured electrical impedance of the bladder tissue. Therefore, the effect of applied pressure on the resulting electrical impedance was considered in this study (all of the measurements were taken on points that had benign histology). An excessive amount of the applied pressure beyond the first visible indentation (first recordable reading) pressure has a significant effect on the impedance of the bladder tissue (p < 0.001). Then, to reduce the effect of pressure on the measured bio-impedance, the effect of a larger probe (10 mm diameter) was considered (p < 0.001). Increasing the probe contact area is one way to reduce the pressure effect on measurements; however this is difficult in practice in the in vivo situation.     

Effect of endurance training on retinol‐binding protein 4 gene expression and its protein level in adipose tissue and the liver in diabetic rats induced by a high‐fat diet and streptozotocin

Aims/Introduction

The present study was designed to investigate from which tissues the decrease in retinol‐binding protein 4 (RBP4) expression could contribute to the improvement of serum RBP4 and insulin resistance (IR) after endurance training.

Materials and Methods

Male 7‐week‐old Wistar rats were randomly assigned into four groups including control (C), trained (T), diabetic control (DC) and trained diabetic (TD). At 8 weeks‐of‐age, diabetes was induced by a high‐fat diet and intraperitoneal injection of low‐dose streptozotocin (STZ; 35 mg/kg). Rats in the T and TD groups carried out a 7‐week exercise program on a motorized treadmill (15–20 m/min for 20 min/day for 5 weeks), whereas the C and DC remained sedentary in their cages. Tissues gene expression and protein levels of RBP4 were assessed by using real‐time polymerase chain reaction and western blot, respectively, while serum RBP4 was measured using an enzyme‐linked immunosorbent assay kit.

Results

Exercise significantly improved IR and reduced serum concentration of RBP4 in the TD group. This reduction of serum RBP4 was accompanied by decreased RBP4 protein expression in visceral fat tissue. In contrast, exercise had no significant effect on RBP4 expression in liver and subcutaneous fat tissue in the TD group. Exercise also significantly decreased RBP4 gene expression in visceral fat tissue and muscle, whereas the effect of exercise on liver RBP4 messenger ribonucleic acid expression was not significant.

Conclusions

The present study showed that the mechanism for RBP4 reducing the effect of endurance training could involve decreased RBP4 messenger ribonucleic acid expression and its protein level in adipose tissue in STZ‐induced diabetic rats.     

Frequency and Correlation of Common Genes Copy Number Alterations in Childhood Acute Lymphoblastic Leukemia with Prognosis

Objective: It was shown by genomic profiling that despite no detectable chromosomal abnormalities a proportion of children with pre-B acute lymphoblastic leukemia harbors copy number alterations (CNA) of genes playing role in B-cell development and function. The aim of the study was to determine the frequency of CNA in pediatric acute lymphoblastic leukemia and correlate these findings with clinical outcome. Methods: DNA extracted from peripheral blood or bone marrow at diagnosis/relapse of fifty newly diagnosed children with precursor B-cell acute lymphoblastic leukemia was analyzed for CNA with multiplex ligation-dependent probe amplification. Results: The analysis revealed 76 CNA in 24 patients most frequently found in PAR1 (17%), CDKN2A/B (15.7%) and PAX5 (14.4%) genes. There were significant CNA co-occurrences between PAX5, CDKN2A/B, BTG1, ETV6, PAR1 or XP22 genes, (p <0.020) and the high-risk group. There was a significant correlation between EBF1, RB1, and IKZF1 alterations and bone marrow relapse. Patients with CNA in screened genes are more likely to succumb to their disease except for those with PAR1 or XP22 genes (p <0.050). Conclusion: The multiplex ligation-dependent probe amplification could be considered as an independent diagnostic tool allowing prompt identification of patients at high risk of treatment failure and, subsequently, a more adequate treatment approach.     

Association of Vitamin D Status with SARS-CoV-2 Infection or COVID-19 Severity: A Systematic Review and Meta-analysis

This systematic review was conducted to summarize and clarify the evidence on the association between 25-hydroxyvitamin-D [25(OH)D] concentrations and coronavirus disease 2019 (COVID-19) risk and outcomes. PubMed, Scopus, and Web of Science databases and Google Scholar were searched up to 26 November 2020. All retrospective and prospective cohort, cross-sectional, case-control, and randomized controlled trial studies that investigated the relation between 25(OH)D and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 severity were included. Thirty-nine studies were included in the current systematic review. In studies that were adjusted (OR: 1.77; 95% CI: 1.24, 2.53; I²: 44.2%) and nonadjusted for confounders (OR: 1.75; 95% CI: 1.44, 2.13; I²: 33.0%) there was a higher risk of SARS-CoV-2 infection in the vitamin D deficiency (VDD) group. Fifteen studies evaluated associations between VDD and composite severity. In the studies that were adjusted (OR: 2.57; 95% CI: 1.65, 4.01; I² = 0.0%) and nonadjusted for confounders (OR: 10.61; 95% CI: 2.07, 54.23; I² = 90.8%) there was a higher severity in the VDD group. Analysis of studies with crude OR (OR: 2.62; 95% CI: 1.13, 6.05; I²: 47.9%), and adjusted studies that used the Cox survival method (HR: 7.67; 95% CI: 3.92, 15.03; I²: 0.0%) indicated a significant association of VDD with mortality, while in adjusted studies that used logistic regression, no relation was observed (OR: 1.05; 95% CI: 0.63, 1.75; I²: 76.6%). The results of studies that examined relations between VDD and intensive care unit (ICU) admission, pulmonary complications, hospitalization, and inflammation were inconsistent. In conclusion, although studies were heterogeneous in methodological and statistical approach, most of them indicated a significant relation between 25(OH)D and SARS-CoV-2 infection, COVID-19 composite severity, and mortality. With regard to infection, caution should be taken in interpreting the results, due to inherent study limitations. For ICU admission, inflammation, hospitalization, and pulmonary involvement, the evidence is currently inconsistent and insufficient.     

Determinants of social activity and work status after coronary bypass surgery

Despite the occurrence of adverse events after coronary artery bypass, the degree of social integration can be increased following this operation. This study addresses the predictive power of risk factors as well as clinical status in determining long-term social functioning and rate of return to work following isolated bypass surgery. A prospective cohort study was conducted in 178 patients who underwent isolated bypass surgery between 2004 and 2007. Information on work status and social relationships was obtained 1-2 days before surgery and during a mean follow-up of 29.4 ± 1.1 months. The proportion of patients who engaged in social activities at 2, 3, and 4 years of follow-up was 0.3, 0.6, and just over 0.8, respectively, and the proportion who had returned to work at these time points was 0.2, 0.45, and 0.63, respectively. Social activity after surgery was less in patients with left ventricular dysfunction, cerebrovascular disease, and higher New York Heart Association functional class. The rate of return to work was lower for men and for patients with left ventricular dysfunction, diabetes, cerebrovascular disease, and those who were hospitalized for more than 14 days.     

Dosimetric properties of a flattening filter-free 6-MV photon beam: a Monte Carlo study

Purpose The dosimetric features of an unflattened 6-MV photon beam of an Elekta SL-25 linac was calculated by the Monte Carlo (MC) method. Material and methods The head of the Elekta SL-25 linac was simulated using the MCNP4C MC code. The accuracy of the model was evaluated using measured dosimetric features, including depth dose values and dose profiles in a water phantom. The flattening filter was then removed, and beam dosimetric properties were calculated by the MC method and compared with those of the flattened photon beam. Results Our results showed a significant (twofold) increase in the dose rate for all field sizes. Also, the photon beam spectra for an unflattened beam were softer, which led to a steeper reduction in depth doses. The decrease in the out-of-field dose and increase in the contamination electrons and a buildup region dose were the other consequences of removing the flattening filter. Conclusion Our study revealed that, for recent radiotherapy techniques, the use of multileaf collimators for beam shaping removing the flattening filter could offer some advantages, including an increased dose rate and decreased out-of-field dose.