The Egyptian Cardiothoracic Surgeon (ECTS - E-Journal)
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A heritable form of SMARCE1-related meningiomas with important implications for follow-up and family screening.
No full textChildhood meningiomas are rare. Recently, a new hereditary tumor predisposition syndrome has been discovered, resulting in an increased risk for spinal and intracranial clear cell meningiomas (CCMs) in young patients. Heterozygous loss-of-function germline mutations in the SMARCE1 gene are causative, giving rise to an autosomal dominant inheritance pattern. We report on an extended family with a pediatric CCM patient and an adult CCM patient and several asymptomatic relatives carrying a germline SMARCE1 mutation, and discuss difficulties in genetic counseling for this heritable condition. Because of the few reported cases so far, the lifetime risk of developing meningiomas for SMARCE1 mutation carriers is unclear and the complete tumor spectrum is unknown. There is no surveillance guideline for asymptomatic carriers nor a long-term follow-up recommendation for SMARCE1-related CCM patients as yet. Until more information is available about the penetrance and tumor spectrum of the condition, we propose the following screening advice for asymptomatic SMARCE1 mutation carriers: neurological examination and MRI of the brain and spine, yearly from diagnosis until the age of 18 and once every 3 years thereafter, or in between if there are clinical symptoms. This advice can also be used for long-term patient follow-up. More data is needed to optimize this proposed screening advice
A Structure-Guided Switch in the Regioselectivity of a Tryptophan Halogenase
No full textFlavin-dependent halogenase enzymes are potentially useful biocatalysts for the regioselectively halogenation of aromatic compounds. Haloaromatic compounds can be utilised in the synthesis and biosynthesis of pharmaceuticals and other valuable products. Here we report the first X-ray crystal structure of a tryptophan 6-halogenase (SttH), which enabled key residues that contribute to the regioselectivity in tryptophan halogenases to be identified. Structure-guided mutagenesis resulted in a triple mutant (L460F/P461E/P462T) that exhibited a complete switch in regioselectivity; with the substrate 3-indolepropionate 75% 5-chlorination was observed with the mutant in comparison with 90% 6-chlorination for the wild-type SttH. This is the first clear example of how regiocomplementary halogenase enzymes can be created from a single parent enzyme. The biocatalytic repertoire of SttH was also expanded to include a range of indolic and non-indolic substrates
The Oldest Jurassic Dinosaur: A Basal Neotheropod from the Hettangian of Great Britain
No full textApproximately 40% of a skeleton including cranial and postcranial remains representing a new genus and species of basal neotheropod dinosaur is described. It was collected from fallen blocks from a sea cliff that exposes Late Triassic and Early Jurassic marine and quasi marine strata on the south Wales coast near the city of Cardiff. Matrix comparisons indicate that the specimen is from the lithological Jurassic part of the sequence, below the first occurrence of the index ammonite Psiloceras planorbis and above the last occurrence of the Rhaetian conodont Chirodella verecunda. Associated fauna of echinoderms and bivalves indicate that the specimen had drifted out to sea, presumably from the nearby Welsh Massif and associated islands (St David’s Archipelago). Its occurrence close to the base of the Blue Lias Formation (Lower Jurassic, Hettangian) makes it the oldest known Jurassic dinosaur and it represents the first dinosaur skeleton from the Jurassic of Wales. A cladistic analysis indicates basal neotheropodan affinities, but the specimen retains plesiomorphic characters which it shares with Tawa and Daemonosaurus
Predictive and prognostic values of ERCC1 and XRCC1 in biliary tract cancers
No full textAIMS: To investigate the predictive and prognostic values of DNA repair genes excision repair cross-complementation group 1 (ERCC1) and X-ray repair cross-complementing group 1 (XRCC1) in tumour samples from patients with a diagnosis of biliary tract cancer (BTC). METHODS: Expressions of ERCC1 and XRCC1 were determined by immunohistochemistry (IHC) for 160 patients with BTC and association with clinicopathological features and patient survival was performed to evaluate their predictive and prognostic values. RESULTS: Neoplastic tissue showed much lower nuclear expression compared with non-neoplastic tissue for ERCC1 (median immunostaining score (IS)=0.7 (95% CI 0.2 to 1.3) vs 8.0 (95% CI 5.5 to 8.0),
A prospective study of anal cancer screening in HIV-positive and negative MSM
No full textOBJECTIVE: The study sought to establish the feasibility and acceptability of anal screening among men MSM.DESIGN: Prospective cohort study.SETTING: Sexual health clinics in tertiary care.PATIENTS: Known HIV-positive and negative MSM who have anoreceptive intercourse.INTERVENTION: Anal screening with human papilloma virus (HPV) testing, liquid-based cytology and high-resolution anoscopy with biopsy of anoscopic abnormalities. Participants completed questionnaires at baseline and at 6 months.RESULTS: Anal HPV was highly prevalent in MSM (HIV-positive, 88% and HIV-negative, 78%). Despite the high prevalence of cytological abnormality in both HIV-positive (46.2%) and negative (35.0%) MSM, almost half of anal intraepithelial neoplasia (AIN) of all grades were associated with negative cytology. Anoscopically directed biopsies detected AIN3 or worse (AIN3+) in 14 of 203 (6.9%) of HIV-positive MSM and three of 81 (3.7%) HIV-negative MSM. The corresponding prevalence of AIN2+ was 26.6 and 20.9%, respectively. One case of AIN3 was detected at the second visit. Screening was considered to be highly acceptable by participants.CONCLUSION: The high prevalence of high-risk-HPV and frequency of false negative cytology in this study suggest that high-resolution anoscopy would have most clinical utility, as a primary screening tool for anal cancer in a high-risk group. The prevalence of AIN3+ in HIV-positive MSM lends support for a policy of screening this group, but the high prevalence of lower grade lesions which do not warrant immediate treatment and the limitations of treating high-grade lesions requires careful consideration in terms of a screening policy.</p
Radiation damage haloes in biotite investigated using high resolution transmission electron microscopy
No full textThe complex, nanometer-scale structural changes resulting from long-term α-particle bombardment of the mineral biotite are revealed for the first time using high-resolution transmission electron microscope (HRTEM) imaging. Radiohaloes are the product of high-energy α-particles emitted from radioactive inclusions penetrating into the surrounding mineral over long (∼1.8 Ga) timescales, resulting in intense discoloration attributed to ionization events and structural damage. HRTEM analysis of these radiohaloes reveals the long-term breakdown of the biotite structure into three distinct domains. Nanometer-scale, neo-phase regions of dilated and contracted mica structure, with periodicities comparable to 1:1 phyllosilicates, are bound by semi-amorphous, high-defect density domains. These are periodically interspersed with areas of near-original biotite structure. Across the halo region, damaged crystallites have become misoriented, revealing changes in the mica layer-to-layer spacing. This nanoscale response of the mica structure has profound implications for understanding the performance of phyllosilicates in barrier systems employed in the safe isolation of nuclear waste, as materials such as these will be relied upon to retard radionuclide migration over the lifetime of a geological disposal facility.</p
