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Human twin studies

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https://www.readbyqxmd.com/read/28214981/neural-mechanism-underling-comprehension-of-narrative-speech-and-its-heritability-study-in-a-large-population
#1
Abbas Babajani-Feremi
Comprehension of narratives constitutes a fundamental part of our everyday life experience. Although the neural mechanism of auditory narrative comprehension has been investigated in some studies, the neural correlates underlying this mechanism and its heritability remain poorly understood. We investigated comprehension of naturalistic speech in a large, healthy adult population (n = 429; 176/253 M/F; 22-36 years of age) consisting of 192 twin pairs (49 monozygotic and 47 dizygotic pairs) and 237 of their siblings...
February 18, 2017: Brain Topography
https://www.readbyqxmd.com/read/28185911/transcriptome-analysis-of-monozygotic-twin-brothers-with-childhood-primary-myelofibrosis
#2
Nan Ding, Zhaojun Zhang, Wenyu Yang, Lan Ren, Yingchi Zhang, Jingliao Zhang, Zhanqi Li, Peihong Zhang, Xiaofan Zhu, Xiaojuan Chen, Xiangdong Fang
Primary myelofibrosis (PMF) is a chronic myeloproliferative disorder in human bone marrow. Over 50% of patients with myelofibrosis have mutations in JAK2, MPL, or CALR. However, these mutations are rarely detected in children, suggesting a difference in the pathogenesis of childhood PMF. In this study, we investigated the response to drug treatment of a monozygotic twin pair with typical childhood PMF. The twin exhibited different clinical outcomes despite following the same treatment regimen. The transcriptomic profiles of patient samples after drug treatment (E2 and Y2) were significantly different between the twin pair, which is consistent with the observation that the drug treatment was effective only in the younger brother, despite the twin being genetically identical...
February 6, 2017: Genomics, Proteomics & Bioinformatics
https://www.readbyqxmd.com/read/28177150/commentary-the-skeleton-is-a-storehouse-of-mineral-that-is-plundered-during-lactation-and-fully-replenished-afterwards
#3
Christopher S Kovacs
During lactation, mammals resorb mineral from the maternal skeleton to provide calcium to milk. Rodents lose 25-35% of skeletal ash weight, ash calcium content, and bone mineral content by DXA, and have compromised material properties of bone, as assessed by crushing vertebrae and 3-pt bend tests of femora or tibiae. The strength, stiffness, and toughness of vertebrae, femora, and tibiae are reduced by as much as 60%. The effects of lactation are not uniform throughout the skeleton, but instead resorption is much more marked in the trabecular-rich spine than in the appendicular skeleton or whole body...
February 8, 2017: Journal of Bone and Mineral Research: the Official Journal of the American Society for Bone and Mineral Research
https://www.readbyqxmd.com/read/28166906/the-morphology-of-the-enamel-dentine-junction-in-neanderthal-molars-gross-morphology-non-metric-traits-and-temporal-trends
#4
Robert M G Martin, Jean-Jacques Hublin, Philipp Gunz, Matthew M Skinner
This study explores the morphological differences between the enamel-dentine junction (EDJ) of maxillary and mandibular molars of Neanderthals (n = 150) and recent modern humans (n = 106), and between an earlier Neanderthal sample (consisting of Pre-Eemian and Eemian Neanderthals dating to before 115 ka) and a later Neanderthal sample (consisting of Post-Eemian Neanderthals dating to after 115 ka). The EDJ was visualised by segmenting microtomographic scans of each molar. A geometric morphometric methodology compared the positioning of the dentine horns, the shape of the marginal ridge between the dentine horns, and the shape of the cervix...
February 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/28139950/can-early-%C3%AE-human-chorionic-gonadotropin-predict-birth-of-singletons-and-twins-after-in-vitro-fertilization
#5
Ana Póvoa, Milton Severo, Pedro Xavier, Alexandra Matias, Isaac Blickstein
OBJECTIVE: To assess the predictive value for clinical pregnancy outcome of β-hCG level at 13 days after embryo transfer. METHODS: Retrospective study of IVF clinical pregnancies diagnosed at 6 weeks. We calculated the value of β-hCG level at 13 days after embryo transfer to predict live births. RESULTS: We analyzed 177 IVF cycles between 2009 and 2014 (50 singleton births, 50 twin births, 27 sets with a vanishing twin, 43 first trimester singleton pregnancy loss and 7 first trimester total twin pregnancy loss)...
January 31, 2017: Journal of Maternal-fetal & Neonatal Medicine
https://www.readbyqxmd.com/read/28132423/xenopus-an-ideal-model-organism-to-study-laterality-in-conjoined-twins
#6
REVIEW
Matthias Tisler, Axel Schweickert, Martin Blum
Conjoined twins occur at low frequency in all vertebrates including humans. Many twins fused at the chest or abdomen display a very peculiar laterality defect: while the left twin is normal with respect to asymmetric organ morphogenesis and placement (situs solitus), the organ situs is randomized in right twins. Although this phenomenon has fascinated already some of the founders of experimental embryology in the 19th and early 20th century, such as Dareste, Fol, Warynsky and Spemann, its embryological basis has remained enigmatic...
January 2017: Genesis: the Journal of Genetics and Development
https://www.readbyqxmd.com/read/28131012/uniqueness-of-the-anterior-dentition-three-dimensionally-assessed-for-forensic-bitemark-analysis
#7
A Franco, G Willems, Phc Souza, W Coucke, P Thevissen
The uniqueness of the human dentition (UHD) is an important concept in the comparative process in bitemark analysis. During this analysis, the incisal edges of the suspects' teeth are matched with the bitemarks collected from the victim's body or crime scenes. Despite playing an essential part to exclude suspects, the UHD contained in the involved incisal tooth edges remains an assumption on bitemark level. The present study was aimed, first, to investigate three-dimensionally (3D) the UHD within different quantities of dental material from the incisal edges; second, to test these outcomes in a bidimensional (2D) simulation...
February 2017: Journal of Forensic and Legal Medicine
https://www.readbyqxmd.com/read/28115509/the-tat-substrate-sufi-is-critical-for-the-ability-of-yersinia-pseudotuberculosis-to-cause-systemic-infection
#8
Ummehan Avican, Tugrul Doruk, Yngve Östberg, Anna Fahlgren, Åke Forsberg
The Twin-arginine translocation (Tat) system targets folded proteins across the inner membrane and it is crucial for virulence in many important human pathogenic bacteria. Tat has been shown to be required for virulence of Yersinia pseudotuberculosis and we recently showed that the system is critical for different virulence related stress responses as well as for iron uptake. In this study, we wanted to address the role of the Tat substrates in in vivo virulence. Therefore, 22 genes encoding potential Tat substrates were mutated and each mutant was evaluated in competitive oral infection of mice...
January 23, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28105968/situs-inversus-totalis-in-twins-a-brief-review-and-a-life-history-twin-research-twin-studies-of-trisomy-21-monozygotic-twin-concordance-for-bilateral-coronoid-hyperplasia-prenatal-hormonal-effects-in-mixed-sex-non-human-primate-litters-insurance-mandates-and
#9
Nancy L Segal
The presence of situs inversus totalis (full reversal of internal organs) in twins is briefly reviewed. Information gathered from 35-year-old monozygotic (MZ) female twin pair discordant for this condition is presented. This is followed by summaries of research on the frequency of trisomy 21 (Down syndrome) in twins, the first case of MZ twin concordance for bilateral coronoid hyperplasia, prenatal hormonal effects in mixed-sex non-human primate litters, and links between insurance mandates and twinning following in vitro fertilization...
February 2017: Twin Research and Human Genetics: the Official Journal of the International Society for Twin Studies
https://www.readbyqxmd.com/read/28103232/a-model-of-compound-heterozygous-loss-of-function-alleles-is-broadly-consistent-with-observations-from-complex-disease-gwas-datasets
#10
Jaleal S Sanjak, Anthony D Long, Kevin R Thornton
The genetic component of complex disease risk in humans remains largely unexplained. A corollary is that the allelic spectrum of genetic variants contributing to complex disease risk is unknown. Theoretical models that relate population genetic processes to the maintenance of genetic variation for quantitative traits may suggest profitable avenues for future experimental design. Here we use forward simulation to model a genomic region evolving under a balance between recurrent deleterious mutation and Gaussian stabilizing selection...
January 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28100283/genetic-influences-on-hormonal-markers-of-chronic-hypothalamic-pituitary-adrenal-function-in-human-hair
#11
E M Tucker-Drob, A D Grotzinger, D A Briley, L E Engelhardt, F D Mann, M Patterson, C Kirschbaum, E K Adam, J A Church, J L Tackett, K P Harden
BACKGROUND: Cortisol is the primary output of the hypothalamic-pituitary-adrenal (HPA) axis and is central to the biological stress response, with wide-ranging effects on psychiatric health. Despite well-studied biological pathways of glucocorticoid function, little attention has been paid to the role of genetic variation. Conventional salivary, urinary and serum measures are strongly influenced by diurnal variation and transient reactivity. Recently developed technology can be used to measure cortisol accumulation over several months in hair, thus indexing chronic HPA function...
January 19, 2017: Psychological Medicine
https://www.readbyqxmd.com/read/28095889/evolution-of-gut-microbiota-composition-from-birth-to-24-weeks-in-the-infantmet-cohort
#12
Cian J Hill, Denise B Lynch, Kiera Murphy, Marynka Ulaszewska, Ian B Jeffery, Carol Anne O'Shea, Claire Watkins, Eugene Dempsey, Fulvio Mattivi, Kieran Touhy, R Paul Ross, C Anthony Ryan, Paul W O' Toole, Catherine Stanton
BACKGROUND: The gut is the most extensively studied niche of the human microbiome. The aim of this study was to characterise the initial gut microbiota development of a cohort of breastfed infants (n = 192) from 1 to 24 weeks of age. METHODS: V4-V5 region 16S rRNA amplicon Illumina sequencing and, in parallel, bacteriological culture. The metabolomic profile of infant urine at 4 weeks of age was also examined by LC-MS. RESULTS: Full-term (FT), spontaneous vaginally delivered (SVD) infants' microbiota remained stable at both phylum and genus levels during the 24-week period examined...
January 17, 2017: Microbiome
https://www.readbyqxmd.com/read/28056983/influence-of-endometrial-thickness-on-treatment-outcomes-following-in-vitro-fertilization-intracytoplasmic-sperm-injection
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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...
February 2017: Fertility and Sterility
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