Solving the riddle of codon usage preferences: a test for translational selection

Translational selection is responsible for the unequal usage of synonymous codons in protein coding genes in a wide variety of organisms. It is one of the most subtle and pervasive forces of molecular evolution, yet, establishing the underlying causes for its idiosyncratic behaviour across living kingdoms has proven elusive to researchers over the past 20 years. In this study, a statistical model for measuring translational selection in any given genome is developed, and the test is applied to 126 fully sequenced genomes, ranging from archaea to eukaryotes. It is shown that tRNA gene redundancy and genome size are interacting forces that ultimately determine the action of translational selection, and that an optimal genome size exists for which this kind of selection is maximal. Accordingly, genome size also presents upper and lower boundaries beyond which selection on codon usage is not possible. We propose a model where the coevolution of genome size and tRNA genes explains the observed patterns in translational selection in all living organisms. This model finally unifies our understanding of codon usage across prokaryotes and eukaryotes. Helicobacter pylori, Saccharomyces cerevisiae and Homo sapiens are codon usage paradigms that can be better understood under the proposed model

Cutaneous Implantation Metastasis of Cholangiocarcinoma after Percutaneous Transhepatic Biliary Drainage

Percutaneous transhepatic biliary decompression is a preoperative surgical adjunct in patients with obstructive jaundice that has been in use since 1973. It is recommended that this procedure be adopted for both palliative treatment in unresectable patients and as a preoperative means of lowering serum bilirubin in patients with potentially resectable malignancies of the pancreas or biliary tract. Metastatic tumor seeding along the transhepatic biliary catheter is an unusual complication resulting from this procedure but there have been a few cases reported in the literature. Below is a report on a 59-year-old woman in whom the percutaneous transhepatic catheter drainage of the biliary tree, performed before surgical resection of a cholangiocarcinoma, caused cutaneous tumor implantation at the catheter site 3 months later. The clinical aspect was morphea-like and histopathologic examination revealed typical features of a dermal metastasis of adenocarcinoma. Immunohistochemistry revealed cytoplasmic positivity for cytokeratin 7-19, specific for the biliary tract epithelium. A review of the literature available led us to conclude that port-site metastasis in patients with obstructive jaundice treated with percutaneous transhepatic biliary decompression was an unusual but possible complication. In fact, many catheter-tract metastatic deposits in the liver parenchyma, detected at autopsy or on operation, are mistakenly identified as hematogenous or lymphatic metastasis and are not attributed to a catheter-related process. We also report on this case because of the atypical morphea-like aspect of the skin metastasis

Eye-Safe Solid-State Quasi-CW Raman Laser with Millisecond Pulse Duration

We demonstrate the first quasi-CW (ms-long pulses, pump duty cycle of 10%) end-diode pumped solid state laser generating eye-safe radiation via intracavity Raman conversion. The output power at the first Stokes wavelength (1524 nm) was 250 mW. A theoretical model was applied to analyze the laser system and provide routes for optimization. The possibility of true CW operation was discussed.Comment: Preprint accepted for publication in Optics Communications on Feb 6, 201

Giant Metatypical Carcinoma: An Unusual Tumor

Meta-typical carcinoma (MTC) or basosquamous carcinoma is a remarkable malignancy with features of both basal and squamous cell carcinoma. It is typically located on the back and face, often with clinical features of basal cell carcinoma but tending to be more aggressive with enhanced prospects of lymph node or distant metastases. Our report describes a huge neglected MTC of the back of ten-year duration, a giant ulcero-vegetative tumor measuring 20 x 25 cm. Histologic examination of specimens from the margins and periphery revealed aspects of both basal and squamous cell carcinoma, while the ulcerated center showed sclerotic tissue without tumor. Radical excision and reconstruction by grafts were performed. No metastases were observed after two years. There are many controversies surrounding the histologic definition and biologic behavior of MTC, including its metastasizing potential. The MTC we describe exhibited benign biologic behavior. This may have been related to an intense inflammatory host response with elimination of neoplastic tissue and consequent local sclerosis evident in the central tumor-free portion. This central tumor regression is to our knowledge a unique finding in MTC

The impact of hyperhidrosis on patients' daily life and quality of life : A qualitative investigation

Background: An understanding of the daily life impacts of hyperhidrosis and how patients deal with them, based on qualitative research, is lacking. This study investigated the impact of hyperhidrosis on the daily life of patients using a mix of qualitative research methods. Methods: Participants were recruited through hyperhidrosis patient support groups such as the Hyperhidrosis Support Group UK. Data were collected using focus groups, interviews and online surveys. A grounded theory approach was used in the analysis of data transcripts. Data were collected from 71 participants, out of an initial 100 individuals recruited. Results: Seventeen major themes capturing the impacts of hyperhidrosis were identified; these covered all areas of life including daily life, psychological well-being, social life, professional /school life, dealing with hyperhidrosis, unmet health care needs and physical impact. Conclusions: Psychosocial impacts are central to the overall impacts of hyperhidrosis, cutting across and underlying the limitations experienced in other areas of life.Peer reviewe

The Dietary Intake of Polyphenols Is Associated with a Lower Risk of Severe Lumbar Spinal Stenosis: A Case-Control Analysis from the PREFACE Study

Polyphenols are naturally occurring compounds endowed with antioxidant and anti-inflammatory properties. We sought to examine the association of dietary polyphenols with the risk of severe lumbar spinal stenosis (LSS), a condition possibly characterized by a high inflammatory component. A case-control study included 156 patients with LSS and indication to surgery and 312 controls, matched (1:2) for sex, age (±6 months), and physical activity. The polyphenol intake was calculated by matching food consumption data from a 188-item food frequency questionnaire with the Phenol-Explorer database regarding the polyphenol content of each reported food. In a multivariable-adjusted logistic regression analysis including lifestyles, sociodemographic factors, and the Mediterranean Diet Score, a 1-standard deviation (SD) increase in dietary polyphenols intake was associated with lower odds of LSS (Odds ratio [OR] = 0.65; 95% CI: 0.47–0.89). Analyses of different polyphenol classes showed that a per 1-SD in the consumption of flavonoids and stilbenes was related to lower LSS risk (OR = 0.57; 95% CI: 0.42–0.78; OR = 0.40; 95% CI: 0.27–0.61, respectively). Further adjustment for the total dietary antioxidant capacity did not modify the strength of these associations. A diet rich in polyphenols is independently associated with a lower risk of severe LSS, possibly through mechanisms that include the anti-inflammatory potential of these bioactive compounds

Room-Temperature Optical-Absorption in Undoped Alpha-AL2O3

Optical absorption over a large dynamic range obtained by two different experimental techniques is reported for an undoped α‐Al2 O3 single crystal. Absorption data are presented in two energy ranges: 0.94–3.5 eV and 4.5–8.6 eV. Vacuum ultraviolet (vuv) absorption measurements were performed on three boules of Czochralski‐grown single‐crystal Al2 O3 with differing starting material purities. The initial powder purities were 99.99%, 99.999%, and 99.999999%. In addition to the vuv measurements, calorimetric absorption results obtained in the visible and near‐infrared (ir) are presented. An empirical formula is obtained that provides an estimate of the absorption coefficient from the near‐ir to the vuv for undoped Al2 O3 . Detailed impurity analyses and sample histories are given for the optical‐quality α‐Al2 O3 utilized herein