171 research outputs found
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Case Study: Pond and Plug Restoration at the Perazzo Meadows in the Northern Sierra Nevadas
Contact Endoscopy as a Novel Technique in the Detection and Diagnosis of Mucosal Lesions in the Head and Neck: A Brief Review
Background. There are a variety of described noninvasive optical detection techniques for evaluation of head and neck mucosal lesions. Contact endoscopy is a promising method of in vivo microscopic examination whereby a rigid telescope is placed on a previously dye-stained mucosa allowing evaluation of the superficial cell layers of the epithelium. This technique produces real-time, magnified images of cellular architecture of surface mucosa comparable to histology without the need for biopsy. In this review, we will briefly summarize the efficacy of CE in the detection of precancerous and cancerous mucosal lesions and its potential as a novel technique in early diagnosis, monitoring, and preoperative assessment of mucosal lesions of the head and neck. Methods. PUBMED, MEDLINE, and COCHRANE search revealed five prospective articles on contact endoscopy for the diagnosis of mucosal lesions in the head and neck. Results. The literature search yielded five prospective studies examining contact endoscopy for the diagnosis of benign versus malignant head and neck mucosal lesions. These reported a sensitivity and specificity of 77–100%, specificity of 66–100% and an accuracy of 72–92%. Conclusion. Contact endoscopy is a promising optical technology that may be a useful adjunct in the evaluation and diagnosis of benign and malignant head and neck mucosal lesions. Future prospective randomized double-blind studies of this detection method are required
A Pilot Study Comparing HPV-Positive and HPV-Negative Head and Neck Squamous Cell Carcinomas by Whole Exome Sequencing.
Background. Next-generation sequencing of cancers has identified important therapeutic targets and biomarkers. The goal of this pilot study was to compare the genetic changes in a human papillomavirus- (HPV-)positive and an HPV-negative head and neck tumor. Methods. DNA was extracted from the blood and primary tumor of a patient with an HPV-positive tonsillar cancer and those of a patient with an HPV-negative oral tongue tumor. Exome enrichment was performed using the Agilent SureSelect All Exon Kit, followed by sequencing on the ABI SOLiD platform. Results. Exome sequencing revealed slightly more mutations in the HPV-negative tumor (73) in contrast to the HPV-positive tumor (58). Multiple mutations were noted in zinc finger genes (ZNF3, 10, 229, 470, 543, 616, 664, 638, 716, and 799) and mucin genes (MUC4, 6, 12, and 16). Mutations were noted in MUC12 in both tumors. Conclusions. HPV-positive HNSCC is distinct from HPV-negative disease in terms of evidence of viral infection, p16 status, and frequency of mutations. Next-generation sequencing has the potential to identify novel therapeutic targets and biomarkers in HNSCC
Phosphorylation of centromeric histone H3 variant regulates chromosome segregation in S. cerevisiae
The centromeric histone H3 variant (CenH3) is essential for chromosome segregation in eukaryotes. We have identified posttranslational modifications of S. cerevisiae CenH3, Cse4. Functional characterization of cse4 phosphorylation mutants showed growth and chromosome segregation defects when combined with kinetochore mutants okp1 and ame1. Using a phosphoserine-specific antibody we showed that the association of phosphorylated Cse4 with centromeres is increased in response to defective microtubule attachment or reduced cohesion. We determined that evolutionarily conserved Ipl1/Aurora B contributes to phosphorylation of Cse4, as levels of phosphorylated Cse4 were reduced at centromeres in ipl1 strains in vivo and in vitro assays showed phosphorylation of Cse4 by Ipl1. Consistent with these results we observed that a phosphomimetic cse4-4SD mutant suppressed the temperature sensitive growth of ipl1-2 and Ipl1 substrate mutants dam1 spc34 and ndc80 that are defective for chromosome biorientation. Furthermore, cell biology approaches using a GFP labeled chromosome showed that cse4-4SD suppressed chromosome segregation defects in dam1 spc34 strains. Based these results we propose that phosphorylation of Cse4 destabilizes defective kinetochores to promote biorientation and ensure faithful chromosome segregation. Taken together, our study provides a detailed analysis, in vivo and in vitro, of Cse4 phosphorylation and its role in promoting faithful chromosome segregation
Switching protein metalloporphyrin binding specificity by design from iron to fluorogenic zinc
Metalloporphyrins play important roles in areas ranging from biology to nanoscience. Using computational design, we converted metalloporphyrin specificity of cytochrome b562 from iron to fluorogenic zinc. The new variant had a near total preference for zinc representing a switch in specificity, which greatly enhanced the negligible aqueous fluorescence of free ZnPP in vitro and in vivo
Photographic measurement of upper-body sitting posture of high school students: A reliability and validity study
<p>Abstract</p> <p>Background</p> <p>All the reported measures of sitting posture, as well as photographs, have one flaw, as these measures are external to the body. These measures use calculations from external bony landmarks to estimate spinal posture, on the understanding that what is being measured externally reflects the shape, health and performance of structures of the underlying spine. Without a comparative measure of the relative position of the structures of the spine, the validity of any external spinal posture measure cannot be established. This paper reports on a study which tests the validity of photographs to measure adolescent sitting posture.</p> <p>Methods</p> <p>The study was conducted in a laboratory at the Department of Human Biology, University of Cape Town. A random sample of 40 adolescents were recruited from the Cape metropolitan schools, to detect differences of three degrees or more between the repeated measures of upright, normal or slouched posture (photographs) and between the posture photographs and LODOX measures. Eligible participants were healthy male and female subjects aged 15 or 16 years old, in Grade 10, and who were undertaking Computer or Computype studies at their schools. Two posture measurement tools were used in the study, namely: Photographs were taken using the Photographic Posture Analysis Method (PPAM) and Radiograph<it>s </it>were taken using the LODOX (LODOX (Pty) Ltd) system. Subjects' posture was assessed in simulated computer workstations. The following angles were measured: the sagittal head angle, cervical angle, protraction/retraction angle, arm angle and the thoracic angle.</p> <p>Results</p> <p>Data from 39 subjects (19 males, 20 females) was used for analysis (17 15-year-olds (7 boys and 10 girls), 22 16-year-olds (12 boys and 10 girls)). All but one photographic angle showed moderate to good correlation with the LODOX angles (Pearson r values 0.67–0.95) with the exception being the shoulder protraction/retraction angle Pearson r values. Bland Altman limits of agreement illustrated a slight bias for all angles. The reliability study findings from repeated photographs demonstrated moderate to good correlation of all angles (ICC values 0.78–0.99).</p> <p>Conclusion</p> <p>The findings of this study suggest that photographs provide valid and reliable indicators of the position of the underlying spine in sitting. Clinically it is important to know whether a patient is showing true progression in relation to a postural intervention. Based on the results of this study, the PPAM can be used in practice as a valid measure of sitting posture.</p
Endotoxaemia in Haemodialysis: A Novel Factor in Erythropoetin Resistance?
Background/Objectives
Translocated endotoxin derived from intestinal bacteria is a driver of systemic inflammation and oxidative stress. Severe endotoxaemia is an underappreciated, but characteristic finding in haemodialysis (HD) patients, and appears to be driven by acute repetitive dialysis induced circulatory stress. Resistance to erythropoietin (EPO) has been identified as a predictor of mortality risk, and associated with inflammation and malnutrition. This study aims to explore the potential link between previously unrecognised endotoxaemia and EPO Resistance Index (ERI) in HD patients.
Methodology/Principal Findings
50 established HD patients were studied at a routine dialysis session. Data collection included weight, BMI, ultrafiltration volume, weekly EPO dose, and blood sampling pre and post HD. ERI was calculated as ratio of total weekly EPO dose to body weight (U/kg) to haemoglobin level (g/dL). Mean haemoglobin (Hb) was 11.3±1.3 g/dL with a median EPO dose of 10,000 [IQR 7,500–20,000] u/wk and ERI of 13.7 [IQR 6.9–23.3] ((U/Kg)/(g/dL)). Mean pre-HD serum ET levels were significantly elevated at 0.69±0.30 EU/ml. Natural logarithm (Ln) of ERI correlated to predialysis ET levels (r = 0.324, p = 0.03) with a trend towards association with hsCRP (r = 0.280, p = 0.07). Ln ERI correlated with ultrafiltration volume, a driver of circulatory stress (r = 0.295, p = 0.046), previously identified to be associated with increased intradialytic endotoxin translocation. Both serum ET and ultrafiltration volume corrected for body weight were independently associated with Ln ERI in multivariable analysis.
Conclusions
This study suggests that endotoxaemia is a significant factor in setting levels of EPO requirement. It raises the possibility that elevated EPO doses may in part merely be identifying patients subjected to significant circulatory stress and suffering the myriad of negative biological consequences arising from sustained systemic exposure to endotoxin
Reimagining the potential of Earth observations for ecosystem service assessments
The benefits nature provides to people, called ecosystem services, are increasingly recognized and accounted for in assessments of infrastructure development, agricultural management, conservation prioritization, and sustainable sourcing. These assessments are often limited by data, however, a gap with tremendous potential to be filled through Earth observations (EO), which produce a variety of data across spatial and temporal extents and resolutions. Despite widespread recognition of this potential, in practice few ecosystem service studies use EO. Here, we identify challenges and opportunities to using EO in ecosystem service modeling and assessment. Some challenges are technical, related to data awareness, processing, and access. These challenges require systematic investment in model platforms and data management. Other challenges are more conceptual but still systemic; they are byproducts of the structure of existing ecosystem service models and addressing them requires scientific investment in solutions and tools applicable to a wide range of models and approaches. We also highlight new ways in which EO can be leveraged for ecosystem service assessments, identifying promising new areas of research. More widespread use of EO for ecosystem service assessment will only be achieved if all of these types of challenges are addressed. This will require non-traditional funding and partnering opportunities from private and public agencies to promote data exploration, sharing, and archiving. Investing in this integration will be reflected in better and more accurate ecosystem service assessments worldwide
Inference of patient-specific pathway activities from multi-dimensional cancer genomics data using PARADIGM
Motivation: High-throughput data is providing a comprehensive view of the molecular changes in cancer tissues. New technologies allow for the simultaneous genome-wide assay of the state of genome copy number variation, gene expression, DNA methylation and epigenetics of tumor samples and cancer cell lines
Evolution of late-stage metastatic melanoma is dominated by aneuploidy and whole genome doubling
Although melanoma is initiated by acquisition of point mutations and limited focal copy number alterations in melanocytes-of-origin, the nature of genetic changes that characterise lethal metastatic disease is poorly understood. Here, we analyze the evolution of human melanoma progressing from early to late disease in 13 patients by sampling their tumours at multiple sites and times. Whole exome and genome sequencing data from 88 tumour samples reveals only limited gain of point mutations generally, with net mutational loss in some metastases. In contrast, melanoma evolution is dominated by whole genome doubling and large-scale aneuploidy, in which widespread loss of heterozygosity sculpts the burden of point mutations, neoantigens and structural variants even in treatment-naïve and primary cutaneous melanomas in some patients. These results imply that dysregulation of genomic integrity is a key driver of selective clonal advantage during melanoma progression
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