Selfish supernumerary chromosome reveals its origin as a mosaic of host genome and organellar sequences

Supernumerary B chromosomes are optional additions to the basic set of A chromosomes, and occur in all eukaryotic groups. They differ from the basic complement in morphology, pairing behavior, and inheritance and are not required for normal growth and development. The current view is that B chromosomes are parasitic elements comparable to selfish DNA, like transposons. In contrast to transposons, they are autonomously inherited independent of the host genome and have their own mechanisms of mitotic or meiotic drive. Although B chromosomes were first described a century ago, little is known about their origin and molecular makeup. The widely accepted view is that they are derived from fragments of A chromosomes and/or generated in response to interspecific hybridization. Through next-generation sequencing of sorted A and B chromosomes, we show that B chromosomes of rye are rich in gene-derived sequences, allowing us to trace their origin to fragments of A chromosomes, with the largest parts corresponding to rye chromosomes 3R and 7R. Compared with A chromosomes, B chromosomes were also found to accumulate large amounts of specific repeats and insertions of organellar DNA. The origin of rye B chromosomes occurred an estimated ～1.1-1.3 Mya, overlapping in time with the onset of the genus Secale (1.7 Mya). We propose a comprehensive model of B chromosome evolution, including its origin by recombination of several A chromosomes followed by capturing of additional A-derived and organellar sequences and amplification of B-specific repeats.     

Endoscopic Management of Barrett’s Esophagus: Advances in Endoscopic Techniques

Barrett??s esophagus (BE) is a well-known premalignant condition that can be associated with the development of dysplasia and adenocarcinoma. In the past, esophagectomy was the standard treatment for patients with BE with high grade dysplasia (HGD) and early cancer (EC). However, esophagectomy is not necessarily the only treatment response to HGD and EC anymore. Over the past decade, a number of endoscopic therapies have been developed for management of BE. These include endoscopic mucosal resection, thermal ablation techniques that use laser irradiation, multipolar electrocoagulation, argon plasma coagulation, photodynamic therapy, and the recently developed cryotherapy and radiofrequency ablation.     

Use of knee height for the estimation of stature in elderly Turkish people and their relationship with cardiometabolic risk factors

The determination of the approximately truest value in height measurement is important in many fields, but it is difficult to perform true measurements, especially in the elderly individuals. We planned to investigate the following items in geriatric Turkish population: to calculate the decrease in height with advancing age by using the standing height measurement and estimated height derived from the knee height; to evaluate the significance of difference between the two measurement methods in the calculation of body mass index (BMI) and waist/height ratio (WHtR); to determine the cut-off value of WHtR according to estimated height in elderly individuals. We studied 551 cases aged between 19 and 97 years. Knee height was measured using a sliding caliper in a sitting position. Linear regression analysis was carried out to derive predictive equations for the estimation of stature with adults (≤50 years of age) according to the gender. This equation was then used to estimate height among elderly subjects. Of the cases, 60.3% were <60 years (mean: 48.75 ± 7.50); 39.7% of the cases were >60 years (mean: 69.51 ± 7.12). Estimated BMI (EBMI) measurements in the females and males >60 years were in average 1.23 kg/m² and 0.92 kg/m² higher than their real BMIs, respectively. EBMI measurements in the females <60 years were 0.32 kg/m² higher than their real BMIs (p < 0.01). There is a statistically significant difference between WHtR in the females of both age groups, and in the males >60 years, as compared to our estimated WHtR (EWHtR) measurements (p < 0.01). The cut-off point of WHtR was 0.61 and 0.58 in the female and male cases of >60 years in our study, respectively. WHtR seemed to be a better anthropometric index that could predict most cardiometabolic risk factors in our study. EWHtR emerged to be a better cardiometabolic risk index especially in the elderly group.     

Hospital acquired infections (HAI) in the elderly: comparison with the younger patients

The aim of this retrospective study is to determine the frequency, type, microbiological characteristics and outcome of HAIs in the elderly (age ≥ 65) and to compare the data with younger patients in a Turkish Training and Research Hospital. From January 2008 to December 2009, the infection control team analyzed HAIs among 60,585 hospitalized patients (20,109 aged ≥ 65 and 40,747 aged between 18 and 64 years) with a total number of 419,017 patient days. A total of 825 HAIs episodes were detected in 607 patients, of which 395 episodes were in 301 elderly patients. The incidence of HAIs per 1000 patient days was 2.49 in the elderly and 1.64 in the younger patients’ group (p < 0.001). The most common site of infection in the elderly patients was the urinary tract, whereas in non-elderly group this was the lower respiratory tract. The incidence density of urinary tract infections, respiratory tract infections, surgical site, skin and soft tissue infections, primary bacteremia, and prosthesis infections were significantly higher in the elderly group (p < 0.05). Gram-negative species were the most frequently isolated agents in both groups. There were no significant differences between the groups in the frequency of isolated pathogens or antibiotic susceptibility patterns. Overall, the fatality rate was found 16.8%. The elderly patients were more likely to have crude mortality rates (22% vs. 12%; p < 0.01). The death was most often related to pneumonia, primary bacteremia or intravascular catheter infections in both groups.     

Association between smoking and outcomes in older adults with atrial fibrillation

Tobacco smoking is a risk factor for atrial fibrillation (AF), but little is known about the impact of smoking in patients with AF. Of the 4060 patients with recurrent AF in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial, 496 (12%) reported having smoked during the past two years. Propensity scores for smoking were estimated for each of the 4060 patients using a multivariable logistic regression model and were used to assemble a matched cohort of 487 pairs of smokers and nonsmokers, who were balanced on 46 baseline characteristics. Cox and logistic regression models were used to estimate the associations of smoking with all-cause mortality and all-cause hospitalization, respectively, during over 5 years of follow-up. Matched participants had a mean age of 70 ± 9 years (± S.D.), 39% were women, and 11% were non-white. All-cause mortality occurred in 21% and 16% of matched smokers and nonsmokers, respectively (when smokers were compared with nonsmokers, hazard ratio=HR=1.35; 95% confidence interval=95%CI=1.01-1.81; p=0.046). Unadjusted, multivariable-adjusted and propensity-adjusted HR (95% CI) for all-cause mortality associated with smoking in the pre-match cohort were: 1.40 (1.13-1.72; p=0.002), 1.45 (1.16-1.81; p=0.001), and 1.39 (1.12-1.74; p=0.003), respectively. Smoking had no association with all-cause hospitalization (when smokers were compared with nonsmokers, odds ratio=OR=1.21; 95%CI=0.94-1.57, p=0.146). Among patients with AF, a recent history of smoking was associated with an increased risk of all-cause mortality, but had no association with all-cause hospitalization.