74 research outputs found

    A generalization of the Mignotte's scheme over Euclidean domains and applications to secret image sharing

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    Secret sharing scheme is an efficient method to hide secret key or secret image by partitioning it into parts such that some predetermined subsets of partitions can recover the secret but remaining subsets cannot. In 1979, the pioneer construction on this area was given by Shamir and Blakley independently. After these initial studies, Asmuth-Bloom and Mignotte have proposed a different (k,n)(k,n) threshold modular secret sharing scheme by using the Chinese remainder theorem. In this study, we explore the generalization of Mignotte's scheme to Euclidean domains for which we obtain some promising results. Next, we propose new algorithms to construct threshold secret image sharing schemes by using Mignotte's scheme over polynomial rings. Finally, we compare our proposed scheme to the existing ones and we show that this new method is more efficient and it has higher security

    Two four-marker haplotypes on 7q36.1 region indicate that the potassium channel gene HERG1 (KCNH2, Kv11.1) is related to schizophrenia: a case control study

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    <p>Abstract</p> <p>Background</p> <p>The pathobiology of schizophrenia is still unclear. Its current treatment mainly depends on antipsychotic drugs. A leading adverse effect of these medications is the acquired long QT syndrome, which results from the blockade of cardiac HERG1 channels (human ether-a-go-go-related gene potassium channels 1) by antipsychotic agents. The HERG1 channel is encoded by <it>HERG1 </it>(<it>KCNH2</it>, <it>Kv11.1</it>) gene and is most highly expressed in heart and brain. Genetic variations in <it>HERG1 </it>predispose to acquired long QT syndrome. We hypothesized that the blockade of HERG1 channels by antipsychotics might also be significant for their therapeutic mode of action, indicating a novel mechanism in the pathogenesis of schizophrenia.</p> <p>Methods</p> <p>We genotyped four single nucleotide polymorphisms (SNPs) in 7q36.1 region (two SNPs, rs1805123 and rs3800779, located on <it>HERG1</it>, and two SNPs, rs885684 and rs956642, at the 3'-downstream intergenic region) and then performed single SNP and haplotype association analyses in 84 patients with schizophrenia and 74 healthy controls after the exclusion of individuals having prolonged or shortened QT interval on electrocardiogram.</p> <p>Results</p> <p>Our analyses revealed that both genotype and allele frequencies of rs3800779 (c.307+585G>T) were significantly different between populations (<it>P </it>= 0.023 and <it>P </it>= 0.018, respectively). We also identified that two previously undescribed four-marker haplotypes which are nearly allelic opposite of each other and located in chr7:150225599-150302147bp position encompassing <it>HERG1 </it>were either overrepresented (A-A-A-T, the at-risk haplotype, <it>P </it>= 0.0007) or underrepresented (C-A-C-G, the protective haplotype, <it>P </it>= 0.005) in patients compared to controls.</p> <p>Conclusions</p> <p>Our results indicate that the potassium channel gene <it>HERG1 </it>is related to schizophrenia. Our findings may also implicate the whole family of HERG channels (HERG1, HERG2 and HERG3) in the pathogenesis of psychosis and its treatment.</p

    Inactivating KISS1 mutation and hypogonadotropic hypogonadism

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    Gonadotropin-releasing hormone (GnRH) is the central regulator of gonadotropins, which stimulate gonadal function. Hypothalamic neurons that produce kisspeptin and neurokinin B stimulate GnRH release. Inactivating mutations in the genes encoding the human kisspeptin receptor (KISS1R, formerly called GPR54), neurokinin B (TAC3), and the neurokinin B receptor (TACR3) result in pubertal failure. However, human kisspeptin loss-of-function mutations have not been described, and contradictory findings have been reported in Kiss1-knockout mice. We describe an inactivating mutation in KISS1 in a large consanguineous family that results in failure of pubertal progression, indicating that functional kisspeptin is important for puberty and reproduction in humans. (Funded by the Scientific and Technological Research Council of Turkey [TÜBİTAK] and others.)http://www.nejm.org/nf201

    Volume CXIV, Number 4, November 7, 1996

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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 stenosis) 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 lifespa

    Rare Plasmacytoid Urothelial Carcinoma of the Bladder: Two Case Reports

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    WOS: 000460995500017PubMed: 29781067Plasmacytoid urothelial carcinoma is a rare and aggressive form of urothelial carcinoma characterized with delayed presentation and poor prognosis. Very few cases of this carcinoma have been reported in the literature. Here, we report and discuss two cases of bladder plasmacytoid urothelial carcinoma of a 57-year-old male presented with renal colic, and a 33-year-old female presented with macroscopic hematuria. Pathologic examinations of the transurethral biopsies revealed urothelial carcinoma with plasmacytoid appearance. Subsequently, immunohistochemical evaluation showed positive expression of epithelial markers and CD138. Additionally, losing of the membranous expression of E-cadherin verified the diagnosis of plasmacytoid urothelial carcinoma

    Heart rate variability and turbulence to determine true coronary artery disease in patients with ST segment depression without angina during exercise stress testing

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    Purpose: ST segment depression without angina during an exercise stress test causes diagnostic problems, particularly in non-diabetic patients. Heart rate variability (HRV) and heart rate turbulence (HRT) are used to evaluate the changes in cardiac autonomic functions and are also both decreased in patients with coronary artery disease. The aim of this study was determine the values of HRV and HRT that discriminate true coronary artery disease from false positive stress test results. Methods: Ninety non-diabetic patients who underwent diagnostic coronary angiography (CA) due to suspected coronary artery disease after ST segment depression without angina during an exercise stress test were enrolled in the study. Prior to CA, 24 hour ambulatory electrocardiogram recordings were taken and HRV and HRT parameters were calculated. Results: Patients were divided into three groups according to the severity of their coronary lesions: (group 1 normal, group 2 non-obstructive and group 3 obstructive. There were no differences among the groups with regards to age, sex, medical history, medications, systolic and diastolic blood pressures, body mass index, fasting glucose, anemia and thyroid status, lipid profile and creatinine clearance. HRV parameters and turbulence slope (TS) were significantly lower while turbulence onset (TO) was significantly higher in group 3 than groups 1 and 2. According to the cut-off values calculated using ROC analysis, SDNN≤69.63 msec, TO > 0.14%, and TS≤2.78 msec/RR have high diagnostic accuracy for predicting obstructive coronary artery disease. Conclusion: HRV and HRT parameters may provide additional information for discriminating between patients who do and do not truly need CA
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