Deciphering the colon cancer genes--report of the InSiGHT-Human Variome Project Workshop, UNESCO, Paris 2010

The Human Variome Project (HVP) has established a pilot program with the International Society for Gastrointestinal Hereditary Tumours (InSiGHT) to compile all inherited variation affecting colon cancer susceptibility genes. An HVP-InSiGHT Workshop was held on May 10, 2010, prior to the HVP Integration and Implementation Meeting at UNESCO in Paris, to review the progress of this pilot program. A wide range of topics were covered, including issues relating to genotype-phenotype data submission to the InSiGHT Colon Cancer Gene Variant Databases (chromium.liacs.nl/LOVD2/colon_cancer/home.php). The meeting also canvassed the recent exciting developments in models to evaluate the pathogenicity of unclassified variants using in silico data, tumor pathology information, and functional assays, and made further plans for the future progress and sustainability of the pilot program.     

Bitemporal Scalp,Lip and Tongue Necrosis in Giant Cell Arteritis: A Rare Presentation

A 74-year-old man was presented with fever, bilateral throbbing temporoparietal headache, jaw claudication, and bilateral loss of vision. On examination, he had bilateral scalp necrosis with impending necrosis of lip and tongue. Temporal artery biopsy was done, and it was compatible with active temporal arteritis. This is one of the rare presentations of giant cell arteritis where there is simultaneous necrosis of scalp, lip, and tongue, and to the best of our knowledge, it is the first case reported from India.     

ENIGMA--evidence-based network for the interpretation of germline mutant alleles: an international initiative to evaluate risk and clinical significance associated with sequence variation in BRCA1 and BRCA2 genes

As genetic testing for predisposition to human diseases has become an increasingly common practice in medicine, the need for clear interpretation of the test results is apparent. However, for many disease genes, including the breast cancer susceptibility genes BRCA1 and BRCA2, a significant fraction of tests results in the detection of a genetic variant for which disease association is not known. The finding of an "unclassified" variant (UV)/variant of uncertain significance (VUS) complicates genetic test reporting and counseling. As these variants are individually rare, a large collaboration of researchers and clinicians will facilitate studies to assess their association with cancer predisposition. It was with this in mind that the ENIGMA consortium (www.enigmaconsortium.org) was initiated in 2009. The membership is both international and interdisciplinary, and currently includes more than 100 research scientists and clinicians from 19 countries. Within ENIGMA, there are presently six working groups focused on the following topics: analysis, clinical, database, functional, tumor histopathology, and mRNA splicing. ENIGMA provides a mechanism to pool resources, exchange methods and data, and coordinately develop and apply algorithms for classification of variants in BRCA1 and BRCA2. It is envisaged that the research and clinical application of models developed by ENIGMA will be relevant to the interpretation of sequence variants in other disease genes.     

How large is the lung recruitability in early acute respiratory distress syndrome: a prospective case series of patients monitored by computed tomography

Introduction  

The benefits of higher positive end expiratory pressure (PEEP) in patients with acute respiratory distress syndrome (ARDS) have been modest, but few studies have fully tested the "open-lung hypothesis". This hypothesis states that most of the collapsed lung tissue observed in ARDS can be reversed at an acceptable clinical cost, potentially resulting in better lung protection, but requiring more intensive maneuvers. The short-/middle-term efficacy of a maximum recruitment strategy (MRS) was recently described in a small physiological study. The present study extends those results, describing a case-series of non-selected patients with early, severe ARDS submitted to MRS and followed until hospital discharge or death.     

How to catch all those mutations--the report of the third Human Variome Project Meeting, UNESCO Paris, May 2010

The third Human Variome Project (HVP) Meeting "Integration and Implementation" was held under UNESCO Patronage in Paris, France, at the UNESCO Headquarters May 10-14, 2010. The major aims of the HVP are the collection, curation, and distribution of all human genetic variation affecting health. The HVP has drawn together disparate groups, by country, gene of interest, and expertise, who are working for the common good with the shared goal of pushing the boundaries of the human variome and collaborating to avoid unnecessary duplication. The meeting addressed the 12 key areas that form the current framework of HVP activities: Ethics; Nomenclature and Standards; Publication, Credit and Incentives; Data Collection from Clinics; Overall Data Integration and Access-Peripheral Systems/Software; Data Collection from Laboratories; Assessment of Pathogenicity; Country Specific Collection; Translation to Healthcare and Personalized Medicine; Data Transfer, Databasing, and Curation; Overall Data Integration and Access-Central Systems; and Funding Mechanisms and Sustainability. In addition, three societies that support the goals and the mission of HVP also held their own Workshops with the view to advance disease-specific variation data collection and utilization: the International Society for Gastrointestinal Hereditary Tumours, the Micronutrient Genomics Project, and the Neurogenetics Consortium.     

Recent updates on electronic cigarette aerosol and inhaled nicotine effects on periodontal and pulmonary tissues

E‐cigarette‐derived inhaled nicotine may contribute to the pathogenesis of periodontal and pulmonary diseases in particular via lung inflammation, injurious, and dysregulated repair responses. Nicotine is shown to have antiproliferative properties and affects fibroblasts in vitro, which may interfere in tissue myofibroblast differentiation in e‐cig users. This will affect the ability to heal wounds by decreasing wound contraction. In periodontics, direct exposure to e‐vapor has been shown to produce harmful effects in periodontal ligament and gingival fibroblasts in culture. This is due to the generation of reactive oxygen species/aldehydes/carbonyls from e‐cig aerosol, leading to protein carbonylation of extracellular matrix and DNA adducts/damage. A limited number of studies regarding the effects of e‐cig in oral and lung health are available. However, no reports are available to directly link the deleterious effects on e‐cigs, inhaled nicotine, and flavorings aerosol on periodontal and pulmonary health in particular to identify the risk of oral diseases by e‐cigarettes and nicotine aerosols. This mini‐review summarizes the recent perspectives on e‐cigarettes including inhaled nicotine effects on several pathophysiological events, such as oxidative stress, DNA damage, innate host response, inflammation, cellular senescence, profibrogenic and dysregulated repair, leading to lung remodeling, oral submucous fibrosis, and periodontal diseases.     

HL-T, a new cell line derived from HL-60 promyelocytic leukemia cell cultures expressing terminal transferase and secreting suppressor activity

A cell line with immature blast cell morphology was isolated from HL-60 promyelocytic leukemia cell cultures and designated HL-T. This new cell type is biphenotypic, expressing terminal transferase (TdT) together with myelomonocytoid immunologic features. TdT enzymatic activity, undetectable in HL-60, was determined to be 140 to 180 units/10(8) HL-T cells by the dGTP-assay, approximately 20% of the activity found in lymphoblastoid cell lines. HL-T predominantly synthesize the known 58- kDa TdT-protein plus a minor 54/56-kDa doublet. The 58-kDa steady state form is nonglycosylated and is phosphorylated. Precursor antigens S3.13 and MY-10, absent on HL-60, are expressed by HL-T; however, the cells are negative for HLA-Dr. Southern blot analysis by hybridization with immunoglobulin heavy chain (JH) and T cell-receptor chain gene (T beta) probes shows JH to be in the germ-line configuration in both cell lines and the T beta gene to be in germ-line in HL-60 but to be rearranged in HL-T. Truncation of the gene encoding the granulocyte-macrophage-colony- stimulating factor (GM-CSF), as found in HL-60, is not observed in HL- T. HL-T are resistant to differentiation-induction by retinoic acid and 1,25-dihydroxyvitamin D3. Cytogenetically HL-T share with HL-60 a deletion of the short arm of chromosome 9 at breakpoint p13, an aberration frequently found in patients with T cell leukemia. In addition, HL-T display t(8;9)(p11;p24) and trisomy 20. Tetraploidy is observed in 80% of HL-T metaphases with aberrations identical to those in the diploid karyotype. Like HL-60, the new line shows some surface- antigenic-T cell characteristics. Despite an antigenic pattern most consistent with that of helper-inducer T cells (T4+, D44+/-, 4B4+, 2H4- , TQ1+/-), HL-T cells and their conditioned culture medium suppress antigen, mitogen, and mixed-leukocyte-culture-mediated lymphocyte proliferation.     

A Multifactorial Likelihood Model for MMR Gene Variant Classification Incorporating Probabilities Based on Sequence Bioinformatics and Tumor Characteristics: A Report from the Colon Cancer Family Registry

Mismatch repair (MMR) gene sequence variants of uncertain clinical significance are often identified in suspected Lynch syndrome families, and this constitutes a challenge for both researchers and clinicians. Multifactorial likelihood model approaches provide a quantitative measure of MMR variant pathogenicity, but first require input of likelihood ratios (LRs) for different MMR variation‐associated characteristics from appropriate, well‐characterized reference datasets. Microsatellite instability (MSI) and somatic BRAF tumor data for unselected colorectal cancer probands of known pathogenic variant status were used to derive LRs for tumor characteristics using the Colon Cancer Family Registry (CFR) resource. These tumor LRs were combined with variant segregation within families, and estimates of prior probability of pathogenicity based on sequence conservation and position, to analyze 44 unclassified variants identified initially in Australasian Colon CFR families. In addition, in vitro splicing analyses were conducted on the subset of variants based on bioinformatic splicing predictions. The LR in favor of pathogenicity was estimated to be ～12‐fold for a colorectal tumor with a BRAF mutation‐negative MSI‐H phenotype. For 31 of the 44 variants, the posterior probabilities of pathogenicity were such that altered clinical management would be indicated. Our findings provide a working multifactorial likelihood model for classification that carefully considers mode of ascertainment for gene testing.     

β1-Adrenoceptor stimulation suppresses endothelial IKCa-channel hyperpolarization and associated dilatation in resistance arteries

Background and Purpose

In small arteries, small conductance Ca²⁺-activated K⁺ channels (SK_Ca) and intermediate conductance Ca²⁺-activated K⁺ channels (IK_Ca) restricted to the vascular endothelium generate hyperpolarization that underpins the NO- and PGI₂-independent, endothelium-derived hyperpolarizing factor response that is the predominate endothelial mechanism for vasodilatation. As neuronal IK_Ca channels can be negatively regulated by PKA, we investigated whether β-adrenoceptor stimulation, which signals through cAMP/PKA, might influence endothelial cell hyperpolarization and as a result modify the associated vasodilatation.

Experimental Approach

Rat isolated small mesenteric arteries were pressurized to measure vasodilatation and endothelial cell [Ca²⁺]_i, mounted in a wire myograph to measure smooth muscle membrane potential or dispersed into endothelial cell sheets for membrane potential recording.

Key Results

Intraluminal perfusion of β-adrenoceptor agonists inhibited endothelium-dependent dilatation to ACh (1 nM–10 μM) without modifying the associated changes in endothelial cell [Ca²⁺]_i. The inhibitory effect of β-adrenoceptor agonists was mimicked by direct activation of adenylyl cyclase with forskolin, blocked by the β-adrenoceptor antagonists propranolol (non-selective), atenolol (β₁) or the PKA inhibitor KT-5720, but remained unaffected by ICI 118 551 (β₂) or glibenclamide (ATP-sensitive K⁺ channels channel blocker). Endothelium-dependent hyperpolarization to ACh was also inhibited by β-adrenoceptor stimulation in both intact arteries and in endothelial cells sheets. Blocking IK_Ca {with 1 μM 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34)}, but not SK_Ca (50 nM apamin) channels prevented β-adrenoceptor agonists from suppressing either hyperpolarization or vasodilatation to ACh.

Conclusions and Implications

In resistance arteries, endothelial cell β₁-adrenoceptors link to inhibit endothelium-dependent hyperpolarization and the resulting vasodilatation to ACh. This effect appears to reflect inhibition of endothelial IK_Ca channels and may be one consequence of raised circulating catecholamines.