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Human twin studies

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https://www.readbyqxmd.com/read/28056983/influence-of-endometrial-thickness-on-treatment-outcomes-following-in-vitro-fertilization-intracytoplasmic-sperm-injection
#1
Ning-Zhao Ma, Lei Chen, Wei Dai, Zhi-Qin Bu, Lin-Li Hu, Ying-Pu Sun
BACKGROUND: The study was designed to investigate the roles of endometrial thickness (EMT) at the day of human chorionic gonadotropin (hCG) administration on pregnancy outcomes in a large patient population. METHODS: This retrospective cohort study included 9,952 patients undergoing their first IVF/ICSI with autologous oocytes from January 2011 to January 2015. Patients were divided into three groups based on the EMT (group A:≤8 mm; group B: 9-14 mm and group C:≥15 mm)...
January 5, 2017: Reproductive Biology and Endocrinology: RB&E
https://www.readbyqxmd.com/read/28034837/research-progress-of-regulatory-mechanism-of-dna-methylation-in-complex-traits-using-monozygotic-twins
#2
Liu Shuli, Zhang Shengli, Yu Ying
Coming from a single zygote, monozygotic (MZ) twins share nearly all of their genetic materials and are almost strikingly similar in appearance. Yet they are often discordant for important phenotypes including complex diseases. The study of discordant MZ twins allows us to understand the role of epigenetics in complex traits by controlling many potential confounders, such as genetic factors, maternal effects, age and sex. As we know, DNA methylation is the most stable epigenetic modification. In human, many causal genes, regulating disease status by DNA methylation modification in imprinting disorders, psychological disorders, autoimmune diseases and cancers, have been discovered, which provides a foundation for studying epigenetic regulation of diseases and application of epigenetic drugs...
December 20, 2016: Yi Chuan, Hereditas
https://www.readbyqxmd.com/read/28009044/disease-concordant-twins-empower-genetic-association-studies
#3
Qihua Tan, Weilong Li, Fabio Vandin
Genome-wide association studies with moderate sample sizes are underpowered, especially when testing SNP alleles with low allele counts, a situation that may lead to high frequency of false-positive results and lack of replication in independent studies. Related individuals, such as twin pairs concordant for a disease, should confer increased power in genetic association analysis because of their genetic relatedness. We conducted a computer simulation study to explore the power advantage of the disease-concordant twin design, which uses singletons from disease-concordant twin pairs as cases and ordinary healthy samples as controls...
December 23, 2016: Annals of Human Genetics
https://www.readbyqxmd.com/read/28003839/twin-arginine-translocation-system-in-secretory-expression-of-recombinant-human-growth-hormone
#4
Mohammad Reza Bagherinejad, Hamid Mir-Mohammad Sadeghi, Daryoush Abedi, C Perry Chou, Fatemeh Moazen, Mohammad Rabbani
Recombinant protein production in E. coli has several advantages over other expression systems. Misfolding, inclusion body formation, and lack of eukaryotic post translational modification are the most disadvantages of this system. Exporting of correctly folded proteins to the outside of reductive cytoplasmic environment through twin-arginine system could help to pass these limiting steps. Two signal sequences, TorA and SufI are used at N-terminal of human growth hormone (hGH) bearing DsbA gene sequence at C-terminal to enhance folding...
December 2016: Research in Pharmaceutical Sciences
https://www.readbyqxmd.com/read/27922732/dental-caries-and-associated-factors-in-twins-with-down-syndrome-a-case-report
#5
Maurício José Santos Moreira, Carolina Schwertner, Ana Paula Dall'Onder, Natália Mincato Klaus, Clarissa Cavalcanti Fatturi Parolo, Lina Naomi Hashizume
Down syndrome (DS) is the most common genetic disorder in humans, but its incidence in monozygotic twins is extremely rare. The aim of this study was to determine the factors associated with dental caries in a pair of monozygotic twin girls with DS, where one had caries experience and the other did not. Clinical examination, salivary Streptococcus mutans (S. mutans) levels and their genotypic diversity, the biochemical composition of the dental biofilm, the frequency of sucrose consumption, and toothbrushing habits were assessed from the twin girls...
December 6, 2016: Special Care in Dentistry
https://www.readbyqxmd.com/read/27917752/genetic-and-environmental-factors-in-invasive-cervical-cancer-design-and-methods-of-a-classical-twin-study
#6
Dorothy A Machalek, John D Wark, Sepehr N Tabrizi, John L Hopper, Minh Bui, Gillian S Dite, Alyssa M Cornall, Marian Pitts, Dorota Gertig, Bircan Erbas, Suzanne M Garland
BACKGROUND: Persistent high-risk human papillomavirus (HPV) infection is a necessary prerequisite for development of cervical cancer and its precursor lesion, high-grade squamous intraepithelial lesion (HSIL). However, HPV infection is not sufficient to drive this process, and genetic and environmental factors may also play a role. METHODS/DESIGN: The Cervical Cancer, Genetics and Environment Twin Study was established to investigate the environmental and genetic influences on variation in susceptibility to cervical pre-cancer in 25- to 69-year-old monozygotic (MZ) and dizygotic (DZ) twins recruited through the Australian Twin Registry...
December 5, 2016: Twin Research and Human Genetics: the Official Journal of the International Society for Twin Studies
https://www.readbyqxmd.com/read/27916985/the-obese-brain-as-a-heritable-phenotype-a-combined-morphometry-and-twin-study
#7
C M Weise, P Piaggi, M Reinhardt, K Chen, C R Savage, J Krakoff, B Pleger
BACKGROUND: Body weight and adiposity are heritable traits. To date it remains unknown whether obesity-associated brain structural alterations are under a similar level of genetic control. METHODS: For this study we utilized magnetic resonance imaging (MRI) data from the Human Connectome Project. Voxel based morphometry (VBM) was used to investigate associations between body mass index (BMI) and regional gray matter volume (GMV) in a sample of 875 young adults with a wide BMI range (386m/489f; age 28...
December 5, 2016: International Journal of Obesity: Journal of the International Association for the Study of Obesity
https://www.readbyqxmd.com/read/27916207/integrating-insulin-into-single-step-culture-medium-regulates-human-embryo-development-in%C3%A2-vitro
#8
Mohamed Fawzy, Mohamed Sabry, Mohamed Nour, Mohamed Y Abdelrahman, Eman Roshdy, Yasmin Magdi, Hazem Abdelghafar
OBJECTIVE: To evaluate the effect of supplementing single-step embryo culture medium with insulin on human embryo development. DESIGN: Comparative study. SETTING: Two private centers. PATIENT(S): The study involved a sibling oocyte split of 5,142 retrieved oocytes from 360 patients. INTERVENTION(S): Sibling oocytes split after intracytoplasmic sperm injection for culture from day 0 through day 5 or 6 in insulin-supplemented or control medium...
December 1, 2016: Fertility and Sterility
https://www.readbyqxmd.com/read/27909831/the-2017-international-workshop-on-statistical-genetic-methods-for-human-complex-traits-formerly-the-methodology-of-twin-and-family-studies-advanced-workshop-march-6th-march-10th-2017
#9
https://www.readbyqxmd.com/read/27896708/asymmetric-interference-in-concurrent-time-to-contact-estimation-cousin-or-twin-of-the-psychological-refractory-period-effect
#10
Robin Baurès, Patricia R DeLucia, Megan Olson, Daniel Oberfeld
In a reaction time (RT) task requiring fast responses to two stimuli presented close in time, human observers show a delayed RT to the second stimulus. This phenomenon has been attributed to a psychological refractory period (PRP). A similar asymmetric interference is found when performing multiple concurrent visual time-to-contact (TTC) estimations for moving objects, despite important differences between the tasks. In the present study, we studied the properties of the asymmetric interference found in the TTC task and compared them to the classical PRP effect...
November 28, 2016: Attention, Perception & Psychophysics
https://www.readbyqxmd.com/read/27892484/environmental-factors-linked-to-depression-vulnerability-are-associated-with-altered-cerebellar-resting-state-synchronization
#11
Aldo Córdova-Palomera, Cristian Tornador, Carles Falcón, Nuria Bargalló, Paolo Brambilla, Benedicto Crespo-Facorro, Gustavo Deco, Lourdes Fañanás
Hosting nearly eighty percent of all human neurons, the cerebellum is functionally connected to large regions of the brain. Accumulating data suggest that some cerebellar resting-state alterations may constitute a key candidate mechanism for depressive psychopathology. While there is some evidence linking cerebellar function and depression, two topics remain largely unexplored. First, the genetic or environmental roots of this putative association have not been elicited. Secondly, while different mathematical representations of resting-state fMRI patterns can embed diverse information of relevance for health and disease, many of them have not been studied in detail regarding the cerebellum and depression...
November 28, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27884229/what-have-we-learned-from-the-genetics-of-hypertension
#12
REVIEW
Friedrich C Luft
Twin studies show that about half the risk of hypertension development is inherited. Mendelian hypertension has elucidated astounding basic pathways contributing to hypertension over (presumably) dietary salt intake or directly through increased peripheral vascular resistance. The Mendelian mutations exercise large effects on blood pressure. Inversely, studying the entire human genome for sources signaling blood pressure has yielded many signals with small effects. Thus far, few loci have been validated or translated into targets...
January 2017: Medical Clinics of North America
https://www.readbyqxmd.com/read/27879256/determination-and-regulation-of-body-composition-in-elite-athletes
#13
Peter Sonksen
In 2011, the International Association of Athletics Federations (IAAF) and IOC introduced a 'hyperandrogenism' rule that excluded women with a serum testosterone >10 nmol/L from participating in elite sport. This rule was based on the false premise that the greater lean body mass in men was a consequence of their higher serum testosterone. This rule did not have scientific backing and the Court of Arbitration for Sport subsequently rescinded the rule following an appeal from an Indian athlete barred from the Commonwealth Games...
November 22, 2016: British Journal of Sports Medicine
https://www.readbyqxmd.com/read/27878451/beyond-genetics-what-causes-type-1-diabetes
#14
REVIEW
Zhen Wang, Zhiguo Xie, Qianjin Lu, Christopher Chang, Zhiguang Zhou
Type 1 diabetes (T1D) is an autoimmune disease resulting from T cell-mediated β cell destruction in the pancreas of genetically susceptible individuals. Extensive familial and population genetic studies uncovered the strong linkage and association between HLA gene variants and T1D. Non-HLA genes have also been associated with T1D, such as INS, CTLA4, and PTPN22. T1D is considered as one of the most heritable common diseases. However, evidence that monozygotic twins have incomplete concordance of disease susceptibility provides convincing proof that environmental factors also play important roles in the pathogenesis of the disease...
November 22, 2016: Clinical Reviews in Allergy & Immunology
https://www.readbyqxmd.com/read/27876820/a-method-to-customize-population-specific-arrays-for-genome-wide-association-testing
#15
Erik A Ehli, Abdel Abdellaoui, Iryna O Fedko, Charlie Grieser, Sahar Nohzadeh-Malakshah, Gonneke Willemsen, Eco Jc de Geus, Dorret I Boomsma, Gareth E Davies, Jouke J Hottenga
As an example of optimizing population-specific genotyping assays using a whole-genome sequence reference set, we detail the approach that followed to design the Axiom-NL array which is characterized by an improved imputation backbone based on the Genome of the Netherlands (GoNL) reference sequence and, compared with earlier arrays, a more comprehensive inclusion of SNPs on chromosomes X, Y, and the mitochondria. Common variants on the array were selected to be compatible with the Illumina Psych Array and the Affymetrix UK Biobank Axiom array...
November 23, 2016: European Journal of Human Genetics: EJHG
https://www.readbyqxmd.com/read/27871240/abo-antigen-and-secretor-statuses-are-not-associated-with-gut-microbiota-composition-in-1-500-twins
#16
Emily R Davenport, Julia K Goodrich, Jordana T Bell, Tim D Spector, Ruth E Ley, Andrew G Clark
BACKGROUND: Host genetics is one of several factors known to shape human gut microbiome composition, however, the physiological processes underlying the heritability are largely unknown. Inter-individual differences in host factors secreted into the gut lumen may lead to variation in microbiome composition. One such factor is the ABO antigen. This molecule is not only expressed on the surface of red blood cells, but is also secreted from mucosal surfaces in individuals containing an intact FUT2 gene (secretors)...
November 21, 2016: BMC Genomics
https://www.readbyqxmd.com/read/27867058/application-of-strep-tactin-xt-for-affinity-purification-of-twin-strep-tagged-cb2-a-g-protein-coupled-cannabinoid-receptor
#17
Alexei Yeliseev, Lioudmila Zoubak, Thomas G M Schmidt
Human cannabinoid receptor CB2 belongs to the class A of G protein-coupled receptor (GPCR). High resolution structural studies of CB2 require milligram quantities of purified, structurally intact protein. Here we describe an efficient protocol for purification of this protein using the Twin-Strep-tag/Strep-Tactin XT system. To improve the affinity of interaction of the recombinant CB2 with the resin, the double repeat of the Strep-tag was attached either to the N- or C-terminus of CB2 via a short linker. The CB2 was isolated at high purity from dilute solutions containing high concentrations of detergents, glycerol and salts, by capturing onto the Strep-Tactin XT resin, and was eluted from the resin under mild conditions upon addition of biotin...
November 17, 2016: Protein Expression and Purification
https://www.readbyqxmd.com/read/27855737/genetic-basis-of-chronotype-in-humans-insights-from-three-landmark-gwas
#18
David A Kalmbach, Logan D Schneider, Joseph Cheung, Sarah J Bertrand, Thiruchelvam Kariharan, Allan I Pack, Philip R Gehrman
Chronotype, or diurnal preference, refers to behavioral manifestations of the endogenous circadian system that governs preferred timing of sleep and wake. As variations in circadian timing and system perturbations are linked to disease development, the fundamental biology of chronotype has received attention for its role in the regulation and dysregulation of sleep and related medical and psychiatric illnesses. Twin and family studies have shown that chronotype is a heritable trait, thus directing attention toward its genetic basis...
October 28, 2016: Sleep
https://www.readbyqxmd.com/read/27852683/potential-of-human-twin-embryos-generated-by-embryo-splitting-in-assisted-reproduction-and-research
#19
REVIEW
Laila Noli, Caroline Ogilvie, Yacoub Khalaf, Dusko Ilic
BACKGROUND: Embryo splitting or twinning has been widely used in veterinary medicine over 20 years to generate monozygotic twins with desirable genetic characteristics. The first human embryo splitting, reported in 1993, triggered fierce ethical debate on human embryo cloning. Since Dolly the sheep was born in 1997, the international community has acknowledged the complexity of the moral arguments related to this research and has expressed concerns about the potential for reproductive cloning in humans...
November 16, 2016: Human Reproduction Update
https://www.readbyqxmd.com/read/27852353/the-brazilian-twin-registry
#20
Paulo H Ferreira, Vinicius C Oliveira, Daniela R Junqueira, Lígia C Cisneros, Lucas C Ferreira, Kate Murphy, Juan R Ordoñana, John L Hopper, Luci F Teixeira-Salmela
The Brazilian Twin Registry (BTR) was established in 2013 and has impelled twin research in South America. The main aim of the initiative was to create a resource that would be accessible to the Brazilian scientific community as well as international researchers interested in the investigation of the contribution of genetic and environmental factors in the development of common diseases, phenotypes, and human behavior traits. The BTR is a joint effort between academic and governmental institutions from Brazil and Australia...
December 2016: Twin Research and Human Genetics: the Official Journal of the International Society for Twin Studies
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