338 research outputs found

    Single-fraction gamma-knife radiosurgery with or without previous surgery for cavernous sinus meningiomas: A single-center experience and systematic literature review

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    Background: The most effective treatment method for meningiomas is surgical treatment. However, complete resection of cavernous sinus meningiomas is quite difficult. The biggest reasons for this are; narrow surgical corridor, the optic chiasm is the close relationship between the cranial nerves and anterior cerebral and internal carotid arteries. Gamma knife radiosurgery (GKRS) may be a good option in these lesions with high mortality and morbidity. Aim: This study aimed to evaluate and compare the early effects at a mean of 6 months and 3 years and outcomes between surgery followed by gamma knife radiosurgery (GKRS) and GKRS alone for cavernous sinus meningiomas. Methods: We included 20 patients with cavernous sinus meningioma treated via single fraction Leksell Gamma Knife Perfexion (Elekta Instruments; Stockholm, Sweden) between 2015 and 2018. The mean age of the patients was 54.95 (range: 32-77) years. Nine patients underwent primary surgery (for the resection of extracavernous components of the tumor) followed by GKRS (for the resection of intracavernous components of the tumor) (group A). Meanwhile, 11 patients were managed with GKRS alone (group B). The tumor volume ranged from 2.8 to 32.8 (mean: 14.76) cm3 and the isodose to the tumor margin from 10 to 13.5 (mean: 11.65) Gy. Results: In total, 20 patients were followed up at a mean time of 18.95 (range: 6-36) months. The mean Karnofsky Performance Score of the patients was 95.2%. The mean follow up times of groups A and B were 23.6 and 15 months, respectively. Meanwhile, only patients with a follow up time of at least 6 months were included in the study. The mean follow up time after GKRS in group A was 17.6 months. There was no change in the tumor volume in 15% of patients. In the remaining cases, the tumor volume decreased. The mean tumor regression rates were 82.2% in Group A and 17.7% in Group B. The tumor volume did not decrease in three patients (n = 1, group A and n = 2, group B). Cranial nerve deficits improved, worsened, and remained stable in 46.6%, 26.6%, and 26.6% of cases, respectively. The temporary morbidity rate was 10%. In group A, transient postoperative diabetes insipidus was observed in one patient and atelectasis in another. None of these complications affected the final status of patients. The mortality rate after treatment was 0%. Conclusion: Volume staged GKRS is safe and effective for cavernous sinus meningioma. GKRS is effective for long term tumor growth control and has a low complication rate. Hence, it is the preferred management strategy for tumors with a suitable volume (average tumor diameter: 3 cm or volume: 10 cm3 ). In tumors with a volume of more than 10 mL and/or without a 3 mm safety margin with the optical system, it is recommended to prepare for radiosurgery by cytoreducing the tumor volume surgically. Based on our opinion, the best results were obtained by GKRS to the intracavernous

    Microbial arms race: Ballistic "nematocysts" in dinoflagellates represent a new extreme in organelle complexity

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    We examine the origin of harpoon-like secretory organelles (nematocysts) in dinoflagellate protists. These ballistic organelles have been hypothesized to be homologous to similarly complex structures in animals (cnidarians); but we show, using structural, functional, and phylogenomic data, that nematocysts evolved independently in both lineages. We also recorded the first high-resolution videos of nematocyst discharge in dinoflagellates. Unexpectedly, our data suggest that different types of dinoflagellate nematocysts use two fundamentally different types of ballistic mechanisms: one type relies on a single pressurized capsule for propulsion, whereas the other type launches 11 to 15 projectiles froman arrangement similar to a Gatling gun.Despite their radical structural differences, these nematocysts share a single origin within dinoflagellates and both potentially use a contraction-based mechanism to generate ballistic force. The diversity of traits in dinoflagellate nematocysts demonstrates a stepwise route by which simple secretory structures diversified to yield elaborate subcellular weaponry

    Diaqua­bis(2-chloro­benzoato-κO)bis­(N,N-diethyl­nicotinamide-κN 1)manganese(II)

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    In the monomeric title complex, [Mn(C7H4ClO2)2(C10H14N2O)2(H2O)2], the MnII atom is located on a crystallographic centre of inversion. The asymmetric unit contains one 2-chloro­benzoate (CB) ligand, one diethyl­nicotinamide (DENA) ligand and one coordinated water mol­ecule, all ligands being monodentate. The four O atoms in the equatorial plane around the Mn atom form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two pyridine N atoms of the DENA ligands in the axial positions. The dihedral angle between the carboxyl group and the adjacent benzene ring is 77.9 (11)°, while the pyridine and benzene rings are oriented at a dihedral angle of 45.94 (5)°. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into infinite chains

    Coagulation factor V gene mutation increases the risk of venous thrombosis in Behcet's disease

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    We investigated the prevalence of the coagulation factor V gene G1691A mutation in 64 patients with Behcet's disease (BD) and in 107 apparently healthy individuals. The mutation was present in the heterozygous state in 37.5% of the patients with a history of deep vein thrombosis (12/32) and in 9.4% of the patients without any thrombotic event (3/32). Eleven healthy individuals were also heterozygous for the mutation (10.3%). The prevalence of the mutation in BD patients with and without thrombosis was significantly different (P = 0.0079). We conclude that the factor V gene mutation may play a major role in the development of venous thrombosis in BD

    Turner syndrome and associated problems in turkish children: A multicenter study

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    Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population. Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014. Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosi) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto’s thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%. Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespan. © Journal of Clinical Research in Pediatric Endocrinology

    Molecular dissection of Wnt3a-Frizzled8 interaction reveals essential and modulatory determinants of Wnt signaling activity

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    Background Wnt proteins are a family of secreted signaling molecules that regulate key developmental processes in metazoans. The molecular basis of Wnt binding to Frizzled and LRP5/6 co-receptors has long been unknown due to the lack of structural data on Wnt ligands. Only recently, the crystal structure of the Wnt8-Frizzled8-cysteine-rich-domain (CRD) complex was solved, but the significance of interaction sites that influence Wnt signaling has not been assessed. Results Here, we present an extensive structure-function analysis of mouse Wnt3a in vitro and in vivo. We provide evidence for the essential role of serine 209, glycine 210 (site 1) and tryptophan 333 (site 2) in Fz binding. Importantly, we discovered that valine 337 in the site 2 binding loop is critical for signaling without contributing to binding. Mutations in the presumptive second CRD binding site (site 3) partly abolished Wnt binding. Intriguingly, most site 3 mutations increased Wnt signaling, probably by inhibiting Wnt-CRD oligomerization. In accordance, increasing amounts of soluble Frizzled8-CRD protein modulated Wnt3a signaling in a biphasic manner. Conclusions We propose a concentration-dependent switch in Wnt-CRD complex formation from an inactive aggregation state to an activated high mobility state as a possible modulatory mechanism in Wnt signaling gradients

    Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

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    A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets

    Using Barkhausen Noise to Measure Coating Depth of Coated High-Speed Steel

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    Coated high-speed steel tools are widely used in machining processes as they offer an excellent tool life to cost ratio, but they quickly need replacing once the coated layer is worn away. It would be therefore useful to be able to measure the tool life remaining non-destructively and cheaply. To achieve this, the work presented here aims to measure the thickness of the coated layer of high-speed cutting tools by using Barkhausen noise (BHN) techniques. Coated high-speed steel specimens coated with two different materials (chromium nitride (CrN), titanium nitride (TiN)) were tested using a cost-effective measuring system developed for this study. Sensory features were extracted from the signal received from a pick-up coil and the signal features, Root mean square, peak count, and signal energy, were successfully correlated with the thickness of the coating layer on high-speed steel (HSS) specimens. The results suggest that the Barkhausen noise measuring system developed in this study can successfully indicate the different thickness of the coating layer on CrN/TiN coated HSS specimens
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