Familiality of gender identity disorder in non-twin siblings.

PubMed

Gómez-Gil, Esther; Esteva, Isabel; Almaraz, M Cruz; Pasaro, Eduardo; Segovia, Santiago; Guillamon, Antonio

2010-04-01

Familial studies and reports of co-occurrence of gender identity disorder (GID) within a family may help to clarify the question of whether transsexualism is a familial phenomenon. In a sample of 995 consecutive transsexual probands (677 male-to-female [MF] and 318 female-to-male [FM]), we report 12 pairs of transsexual non-twin siblings (nine pairs of MF siblings, two pairs of MF-FM siblings, and one pair of FM siblings). The present study doubles the number of case reports of co-occurrence of transsexualism in non-twin siblings available in the literature. According to our data, the probability that a sibling of a transsexual will also be transsexual was 4.48 times higher for siblings of MF than for siblings of FM transsexual probands, and 3.88 times higher for the brothers than for the sisters of transsexual probands. Moreover, the prevalence of transsexualism in siblings of transsexuals (1/211 siblings) was much higher than the range expected according to the prevalence data of transsexualism in Spain. The study suggests that siblings of transsexuals may have a higher risk of being transsexual than the general population, and that the risk is higher for brothers than sisters of transsexuals, and for siblings of MF than FM transsexuals. Nevertheless, the risk is low.

Genetic and Environmental Influences on Traits of Gender Identity Disorder: A Study of Japanese Twins Across Developmental Stages.

PubMed

Sasaki, Shoko; Ozaki, Koken; Yamagata, Shinji; Takahashi, Yusuke; Shikishima, Chizuru; Kornacki, Tamara; Nonaka, Koichi; Ando, Juko

2016-10-01

The present study examined: (1) gender and age differences of mean gender identity disorder (GID) trait scores in Japanese twins; (2) the validity of the prenatal hormone transfer theory, which predicts that, in dizygotic (DZ) twin pairs, twins with an opposite-gender co-twin more frequently exhibit GID traits than twins with a same-gender co-twin; and (3) the magnitude of genetic and environmental influences on GID traits as a function of age and gender. Data from 1450 male twin pairs, 1882 female twin pairs, and 1022 DZ male-female pairs ranging from 3 to 26 years of age were analyzed. To quantify individual variances in GID traits, each participant completed four questionnaire items based on criteria for GID from the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Our most important findings were: (1) Japanese females exhibited GID traits more frequently than males and Japanese children exhibited GID traits less frequently than adolescents and adults (among females, the prevalence was 1.6 % in children, 10 % in adolescents, and 12 % in adults; among males, the prevalence was 0.5, 2, and 3 %, respectively); (2) the data did not support the prenatal hormone transfer theory for GID traits; and (3) a large part of the variance for GID traits in children was accounted for by familial factors; however, the magnitude was found to be greater in children than in adolescents or adults, particularly among females. This study suggests that although the prevalence is likely to increase, familial effects are likely to decrease as individuals age.

Dynamic Development in Speaking versus Writing in Identical Twins

ERIC Educational Resources Information Center

Chan, HuiPing; Verspoor, Marjolijn; Vahtrick, Louisa

2015-01-01

Taking a dynamic usage-based perspective, this longitudinal case study compares the development of sentence complexity in speaking versus writing in two beginner Taiwanese learners of English (identical twins) in an extensive corpus consisting of 100 oral and 100 written texts of approximately 200 words produced by each twin over 8 months. Three…

Musical Interests and Talent: Twin Jazz Musicians and Twin Studies/Twin Research: Loss of a Preterm Multiple; Conjoined Twin Conception; Depression in Fathers of Twins; Twin-to-Twin Transfusion Syndrome/Twin News: High-Achieving Twins; Twin Children of a Tennis Star; Conjoined Twin Separation; Twin Delivery to a Giant Panda.

PubMed

Segal, Nancy L

2017-12-01

Findings from twin studies of musical interests and talent are reviewed as a backdrop to the lives and careers of twin jazz musicians, Peter and Will Anderson. The Anderson twins exemplify many aspects of twin research, namely their matched musical abilities, shared musical interests, and common career. This overview is followed by reviews of studies and case reports of bereavement in families who have lost a preterm multiple birth infant, the conception of conjoined twins following in vitro fertilization (IVF), depression in fathers of twins, and twin-to-twin transfusion incidence in monochorionic-diamniotic IVF twin pairs. Twins highlighted in the media include high-achieving identical female twins with nearly identical academic standing, tennis star Roger Federer's two sets of identical twin children, surgical separation of craniopagus conjoined twins, and the rare delivery of twins to a 23-year-old giant panda.

College-age twins: university admission policies / twin research: birth weight and neuromotor performance; transfusion syndrome markers; vanishing twins and fetal sex determination; mz twin discordance for wilson's disease / media: big at birth; planned separation of conjoined twins; x factor twins; Cinema: the identical.

PubMed

Segal, Nancy L

2014-12-01

There is a lack of research findings addressing the unique college admissions issues faced by twins and other multiples. The advantages and disadvantage twins face, as reported by college administrators, twins and families are reviewed. Next, recent research addressing twins' birth weight and neuromotor performance, transfusion syndrome markers, the vanishing twin syndrome and monozygotic (MZ) twin discordance for Wilson's disease is described. News items concerning the birth of unusually large twins, the planned separation of conjoined twins, twin participants in the X Factor games and a film, The Identical, are also summarized.

Identical twins with mature cystic teratomas treated with laparoscopic surgery: Two case reports.

PubMed

Mabuchi, Yasushi; Ota, Nami; Kobayashi, Aya; Tanizaki, Yuko; Minami, Sawako; Ino, Kazuhiko

2017-02-01

Mature cystic teratomas are the most common among all ovarian neoplasms, representing 30-40% of the cases. However, to the best of our knowledge, there have been only two reports of mature cystic teratomas occurring in identical twins to date. We herein report a case of identical twins with mature cystic teratomas who were treated with laparoscopic surgery. A 32-year-old woman was referred to our hospital due to a tumor in the right ovary. The patient underwent laparoscopic resection of the ovarian tumor and the pathological diagnosis was benign mature cystic teratoma. Two years later, the identical twin of the abovementioned patient was referred to our hospital also due to a right ovarian tumor. The patient underwent laparoscopic resection of the ovarian tumor and the pathological diagnosis was benign mature cystic teratoma. Therefore, for early diagnosis, it may be important to consider the possibility of mature cystic teratoma in the identical twin of a patient, even in the absence of symptoms.

Monozygotic male twins concordant for Beckwith-Wiedemann syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clemens, M.; McPherson, E.; Sherer, C.

1994-09-01

The Beckwith-Wiedemann syndrome (BWS) is a multiple congenital anomaly syndrome characterized by macrosomia, macro glossia, visceromegaly, characteristic facies, and in some cases omphalocele, hypoglycemia, hemihypertrophy, and risk of embryonal tumors. Most cases occur sporadically in chromosomally normal individuals, but a few BWS patients have anomalies of 11p and others have evidence of microduplications or paternal isodisomy in this region. In some families with autosomal dominant transmission, BWS maps to 11p15.5, but the mechanism of transmission is not fully understood. BWS has been reported in 11 sets of MZ twins, including 10 female pairs (9 discordant and 1 partially concordant) andmore » one male pair concordant for both BWS & dup 15q11.2-q13. We report a pair of premature male MZ twins with macroglossia, postnatal overgrowth, characteristic BWS facies, and mild developmental delay. One twin had hypoglycemia, but neither had omphalocele or hemihypertrophy and serial abdominal ultrasounds have been normal. DNA fingerprinting confirmed monozygosity. Chromosome studies showed a marker 11p14.2 in one twin only, and molecular genetic studies of the 11p15.5 region showed no evidence of duplication or isodisomy in either twin.« less

Surprising dissimilarities in a newly formed pair of `identical twin' stars

NASA Astrophysics Data System (ADS)

Stassun, Keivan G.; Mathieu, Robert D.; Cargile, Phillip A.; Aarnio, Alicia N.; Stempels, Eric; Geller, Aaron

2008-06-01

The mass and chemical composition of a star are the primary determinants of its basic physical properties-radius, temperature and luminosity-and how those properties evolve with time. Accordingly, two stars born at the same time, from the same natal material and with the same mass, are `identical twins,' and as such might be expected to possess identical physical attributes. We have discovered in the Orion nebula a pair of stellar twins in a newborn binary star system. Each star in the binary has a mass of 0.41+/-0.01 solar masses, identical to within 2per cent. Here we report that these twin stars have surface temperatures differing by ~300K (~10per cent) and luminosities differing by ~50per cent, both at high confidence level. Preliminary results indicate that the stars' radii also differ, by 5-10per cent. These surprising dissimilarities suggest that one of the twins may have been delayed by several hundred thousand years in its formation relative to its sibling. Such a delay could only have been detected in a very young, definitively equal-mass binary system. Our findings reveal cosmic limits on the age synchronization of young binary stars, often used as tests for the age calibrations of star-formation models.

[Panhypopituitarism in one identical twin: the effect of hormone replacement].

PubMed

Del Canho, Harrij; van Alfen-van der Velden, Janiëlle; del Canho, Riwka; Otten, Barto

2011-01-01

Panhypopituitarism in childhood is rare. It is even rarer if the disorder appears in a boy with an identical but healthy twin brother. In such a patient it is useful to study the consequences of the hormone disorder and the effect of hormone replacement. A 6-year-old boy saw a paediatrician because of short stature. He was much shorter than his identical twin brother and he had more abdominal fat mass and a smaller penis. Laboratory tests identified hypothyroidism of central origin, in combination with hypocortisolism and growth hormone deficiency. Hormonal replacement resulted in an improvement in growth rate. At the age of 15 years, testosterone therapy was introduced because puberty had not occurred and his growth rate was low. Finally the patient grew a few centimetres taller than his twin brother. In the first year of life, panhypopituitarism has no negative consequences for growth. After this point, growth is clearly delayed. With sufficient replacement growth can completely catch up.

Twins reunited: scientific and personal perspectives/twin research studies: multiple birth effects on IQ and body size; life style, muscles, and metabolism; monochorionic dizygotic twin with blood chimerism; amniocentesis for twins/twins in the media: identical doctors; freedom fighter for twins; twin scholarships; Auguste and Jean-Felix Piccard; twins born apart.

PubMed

Segal, Nancy L; Mulligan, Christy A

2014-04-01

A reunion of 38-year-old female monozygotic twins took place in Daegu, South Korea, on January 14, 2014. Scientific and personal perspectives on this extraordinary event are provided. A review of timely twin research follows, covering the effects of multiple births on IQ and body size, lifestyle and physical fitness associations, a rare case of a dizygotic twin with blood chimerism and definitional issues surrounding amniocentesis-related loss in multiple birth pregnancies. Interesting and informative mention of twins in the media includes twin doctors, a twin freedom fighter, the availability of college scholarships for twins, a new book about the Piccard family (two of whose members were twins), and co-twins born before and after the new year. A follow-up to a previous mention of identical twin biatheletes is also provided.

Twins less frequent than expected among male births in risk averse populations.

PubMed

Karasek, Deborah; Goodman, Julia; Gemmill, Alison; Falconi, April; Hartig, Terry; Magganas, Aristotle; Catalano, Ralph

2015-06-01

Male twin gestations exhibit higher incidence of fetal morbidity and mortality than singleton gestations. From an evolutionary perspective, the relatively high rates of infant and child mortality among male twins born into threatening environments reduce the fitness of these gestations, making them more vulnerable to fetal loss. Women do not perceive choosing to spontaneously abort gestations although the outcome may result from estimates, made without awareness, of the risks of continuing a pregnancy. Here, we examine whether the non-conscious decisional biology of gestation can be linked to conscious risk aversion. We test this speculation by measuring the association between household surveys in Sweden that gauge financial risk aversion in the population and the frequency of twins among live male births. We used time-series regression methods to estimate our suspected associations and Box-Jenkins modeling to ensure that autocorrelation did not confound the estimation or reduce its efficiency. We found, consistent with theory, that financial risk aversion in the population correlates inversely with the odds of a twin among Swedish males born two months later. The odds of a twin among males fell by approximately 3.5% two months after unexpectedly great risk aversion in the population. This work implies that shocks that affect population risk aversion carry implications for fetal loss in vulnerable twin pregnancies.

Nephrolithiasis in identical twins: the impact of nature vs nurture.

PubMed

Haleblian, George E; Cantor, David A; Sur, Roger L; Assimos, Dean G; Preminger, Glenn M

2007-09-01

To assess possible underlying metabolic abnormalities in three sets of monozygotic twins, to evaluate the interplay among the factors of kidney stone formation, a complex multifactorial process influenced by environmental, genetic and anatomical factors. Three sets of identical twins with either cystine or calcium oxalate stones were identified. Demographic data, medical histories and the results of 24-h urine testing, with samples collected on self-selected diets, were reviewed and analysed. The cystinuric twins had very similar cystine excretion rates, while stone activity was significantly more pronounced in one. Metabolic abnormalities were concordant in one set of twins with calcium oxalate stones, both being hypercalciuric and hyperuricosuric. However, metabolic abnormalities were discordant in the other pair, one twin with hypercalciuria and the other with hypocitraturia. Two of the three pairs had low urinary volume. These results support previous observations that environmental, genetic and potentially, anatomical factors play roles in kidney-stone formation. Additional controlled studies of monozygotic stone-forming twins might help to define the interplay between environmental and genetic factors, and allow the identification of susceptibility genes involved in stone generation.

Neuropathologic assessment of dementia markers in identical and fraternal twins

PubMed Central

Iacono, Diego; Volkman, Inga; Nennesmo, Inger; Pedersen, Nancy L.; Fratiglioni, Laura; Johansson, Boo; Karlsson, David; Winblad, Bengt; Gatz, Margaret

2014-01-01

Twin studies are an incomparable source of investigation to shed light on genetic and non-genetic components of neurodegenerative diseases, as Alzheimer’s disease (AD). Detailed clinicopathologic correlations using twin longitudinal data and postmortem examinations are mostly missing. We describe clinical and pathologic findings of 7 monozygotic (MZ) and dizygotic (DZ) twin pairs. Our findings show good agreement between clinical and pathologic diagnoses in the majority of the twin pairs, with greater neuropathologic concordance in MZ than DZ twins. Greater neuropathologic concordance was found for β-amyloid than tau pathology within the pairs. ApoE4 was associated with higher β-amyloid and earlier dementia onset, and importantly, higher frequency of other co-occurring brain pathologies, regardless of the zygosity. Dementia onset, dementia duration, difference between twins in age at dementia onset and at death, did not correlate with AD pathology. These clinicopathologic correlations of older identical and fraternal twins support the relevance of genetic factors in AD, but not their sufficiency to determine the pathology, and consequently the disease, even in monozygotic twins. It is the interaction among genetic and non-genetic risks which plays a major role in influencing, or probably determining, the degeneration of those brain circuits associated with pathology and cognitive deficits in AD. PMID:24450926

Identical twins in forensic genetics - Epidemiology and risk based estimation of weight of evidence.

PubMed

Tvedebrink, Torben; Morling, Niels

2015-12-01

The increase in the number of forensic genetic loci used for identification purposes results in infinitesimal random match probabilities. These probabilities are computed under assumptions made for rather simple population genetic models. Often, the forensic expert reports likelihood ratios, where the alternative hypothesis is assumed not to encompass close relatives. However, this approach implies that important factors present in real human populations are discarded. This approach may be very unfavourable to the defendant. In this paper, we discuss some important aspects concerning the closest familial relationship, i.e., identical (monozygotic) twins, when reporting the weight of evidence. This can be done even when the suspect has no knowledge of an identical twin or when official records hold no twin information about the suspect. The derived expressions are not original as several authors previously have published results accounting for close familial relationships. However, we revisit the discussion to increase the awareness among forensic genetic practitioners and include new information on medical and societal factors to assess the risk of not considering a monozygotic twin as the true perpetrator. If accounting for a monozygotic twin in the weight of evidence, it implies that the likelihood ratio is truncated at a maximal value depending on the prevalence of monozygotic twins and the societal efficiency of recognising a monozygotic twin. If a monozygotic twin is considered as an alternative proposition, then data relevant for the Danish society suggests that the threshold of likelihood ratios should approximately be between 150,000 and 2,000,000 in order to take the risk of an unrecognised identical, monozygotic twin into consideration. In other societies, the threshold of the likelihood ratio in crime cases may reach other, often lower, values depending on the recognition of monozygotic twins and the age of the suspect. In general, more strictly kept

Discordant transsexualism in male monozygotic twins: neuroanatomical and psychological differences.

PubMed

Andreazza, Tahiana Signorini; Costa, Angelo Brandelli; Massuda, Raffael; Salvador, Jaqueline; Silveira, Esalba Maria; Piccon, Felipe; Carvalho, Renata; Fontanari, Anna Martha Vaitses; Koff, Walter; Belmonte-de-Abreu, Paulo; Lobato, Maria Inês Rodrigues

2014-02-01

One monozygotic male twin pair discordant for transsexualism is described. Both twins were interviewed and tested with the Wechsler Adult Intelligence Scale battery for cognitive functions and they underwent magnetic resonance imaging to measure the volumes of specific cerebral structures. Interviews with the twins and their mother indicated no unusual medical or life history events that could have had a causal role in the emergence of the disorder. Both cognitive function testing and neuroimaging detected differences between the twins that could be related to unexplained epigenetic effects and exogenous hormone usage.

A metric study of insole foot impressions in footwear of identical twins.

PubMed

Nirenberg, Michael S; Krishan, Kewal; Kanchan, Tanuj

2017-11-01

Foot impressions are of utmost importance in crime scene investigations. Foot impressions are available in the form of barefoot prints, sock-clad footprints, and as impressions within footwear. Sometimes suspects leave their footwear at the crime scene, and the insole of this footwear may contain the foot impression of the suspect which may be important evidence linking him or her to the crime. The task of identification based on the analysis of footprints can be challenging when the footprints belonging to one of the identical twin is available for examination. The present study is based on the quantitative measures of the foot impressions in the footwear of adult identical twins. The study was conducted on four sets of female monozygotic twins from the United States of America. A total of 17 length and breadth measurements were taken on each foot impression. A combination of Reel Method and Extended Gunn Method was utilized to produce the measurements. The measurements of the foot impressions were compared among the twins on the right and the left side. Differences were found in the various footprint measurements among the twins. The study's sample size was not large enough to apply robust statistical tests, but the study is significant in that it presents the first detailed comparative analysis of a large number of measurements of insole foot impressions of adult twins. The observations derived from the study are likely to assist forensic investigations in cases involving the foot impressions of the twins. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

The Fourth International Network of Twin Registries: Overview from Osaka/Research Reviews: Familial Fraternal Twinning; Twin Study of Masculine Faces; Physical Aggression and Epigenetics; Prenatal Education for Parents of Twins/Current Events: 2016 Guinness Book of World Records; Oldest Living Male Twins; Twins Reunited at Sixty-Nine; Panda Twins; Twins.com.

PubMed

Segal, Nancy L

2015-12-01

The 4th International Network of Twin Registries (INTR) Consortium Meeting took place in Osaka, Japan, September 28-29, 2015. The venue was the Osaka Medical Center for Medical Innovation and Translational Research. An overview of presentations and other activities is provided. Next, 1930s research on familial fraternal twinning, preference for masculine faces, physical aggression and epigenetics, and a prenatal education program for parents of multiples are described. Current twin-related events include the 2016 Guinness Book of World Records (GWR), the oldest living male twins, newly reunited twins, the birth of panda twins and a controversial twin-based website.

How Do Friends Influence Smoking Uptake? Findings from Qualitative Interviews with Identical Twins

ERIC Educational Resources Information Center

McLeod, Kim; White, Victoria; Mullins, Robyn; Davey, Claire; Wakefield, Melanie; Hill, David

2008-01-01

The smoking behavior of friends is a major risk factor for adolescent smoking uptake. To explore the social context of smoking experimentation and consolidation with a particular focus on friends, the authors interviewed both members of 14 young adult identical twin pairs who were discordant for smoking. The different smoking status of twins was…

Fetal origins of the TEL-AML1 fusion gene in identical twins with leukemia

PubMed Central

Ford, Anthony M.; Bennett, Caroline A.; Price, Cathy M.; Bruin, M. C. A.; Van Wering, Elisabeth R.; Greaves, Mel

1998-01-01

The TEL (ETV6)−AML1 (CBFA2) gene fusion is the most common reciprocal chromosomal rearrangement in childhood cancer occurring in ≈25% of the most predominant subtype of leukemia— common acute lymphoblastic leukemia. The TEL-AML1 genomic sequence has been characterized in a pair of monozygotic twins diagnosed at ages 3 years, 6 months and 4 years, 10 months with common acute lymphoblastic leukemia. The twin leukemic DNA shared the same unique (or clonotypic) but nonconstitutive TEL-AML1 fusion sequence. The most plausible explanation for this finding is a single cell origin of the TEL-AML fusion in one fetus in utero, probably as a leukemia-initiating mutation, followed by intraplacental metastasis of clonal progeny to the other twin. Clonal identity is further supported by the finding that the leukemic cells in the two twins shared an identical rearranged IGH allele. These data have implications for the etiology and natural history of childhood leukemia. PMID:9539781

Midlife Activity Predicts Risk of Dementia in Older Male Twin Pairs

PubMed Central

Carlson, Michelle C.; Helms, Michael J.; Steffens, David C.; Burke, James R.; Potter, Guy G.; Plassman, Brenda L.

2013-01-01

Background Prospective study of dementia to elucidate mechanisms of disease risk factors amenable to modification and specifically to determine whether midlife cognitive and physical leisure activities are associated with delayed onset or reduced risk of dementia within older male twin pairs. Method Co-twin control design using prospectively collected exposure information to predict risk of dementia 20–40 years later. Setting Community-dwelling and nursing home residents living throughout the continental United States. Participants 147 male twin-pairs who were discordant for dementia or age of dementia onset and were members of the NAS-NRC Twin Registry of World War II veterans and participants in the Duke Twins Study of Memory in Aging. Main Outcome Measure Diagnosed dementia using a two-stage screen and full clinical evaluation. Conditional odds ratios were estimated for the association between midlife leisure activities and late life dementia. Results Greater midlife cognitive activity was associated with a 26% risk reduction for dementia onset. Protective effects were most robust in monozygotic twin-pairs, where genetic and early-life influences were most tightly controlled, and for activities that were often cognitive and social in nature. Cognitive activity was particularly protective among monozygotic twin-pairs carrying the APOE4 allele, with a 30% risk reduction. Midlife physical activity did not modify dementia risk. Conclusions Participation in a range of cognitively and socially engaging activities in midlife reduced risk for dementia and AD in twins discordant for onset, particularly among twin-pairs at elevated genetic risk, and may be indicative of an enriched environment. PMID:18790459

A lesson from kidney transplantation among identical twins: Case report and literature review.

PubMed

Rao, Zhengsheng; Huang, Zhongli; Song, Turun; Lin, Tao

2015-09-01

There continues to be disagreement related to the appropriate therapeutic regimen to be used when the donor and the recipient in kidney transplant operations are identical twins. Here we present two cases of kidney transplantation between identical twins. Both recipients had end-stage renal disease (ESRD) caused by primary nephropathy. We also present information gleaned from a literature review of similar cases. The first recipient was a 26-year-old man who experienced biopsy-proven IgA nephropathy 10 months post-transplantation. Mycophenolate mofetil (MMF), angiotensin receptor blockers (ARBs), and steroids were used to reverse this pathologic condition. Till now, 76 months post-transplantation, the patient is stable, and the new kidney is functioning well. The second recipient was a 20-year-old woman who had hematuria and proteinuria 3 months post-transplantation, and crescent glomerulonephritis with mild to moderate interstitial injury was proven by biopsy 11 months postoperatively. This patient did not respond to various treatments and resumed hemodialysis 15 months post-transplantation. These case studies show that immunosuppressive therapy should be maintained in kidney transplant recipients who are identical twins with ESRD caused by initial nephropathy. Copyright © 2015 Elsevier B.V. All rights reserved.

Midlife activity predicts risk of dementia in older male twin pairs.

PubMed

Carlson, Michelle C; Helms, Michael J; Steffens, David C; Burke, James R; Potter, Guy G; Plassman, Brenda L

2008-09-01

This was a prospective study of dementia to elucidate mechanisms of disease risk factors amenable to modification and specifically to determine whether midlife cognitive and physical leisure activities are associated with delayed onset or reduced risk of dementia within older male twin pairs. The co-twin control design used prospectively collected exposure information to predict risk of dementia 20 to 40 years later. The subjects were community-dwelling and nursing home residents living throughout the continental United States. We studied 147 male twin-pairs who were discordant for dementia or age of dementia onset and were members of the National Academy of Sciences-National Research Council Twin Registry of World War II veterans and participants in the Duke Twins Study of Memory in Aging. The main outcome measure was diagnosed dementia by using a two-stage screen and full clinical evaluation. Conditional odds ratios were estimated for the association between midlife leisure activities and late-life dementia. Greater midlife cognitive activity was associated with a 26% risk reduction for dementia onset. Protective effects were most robust in monozygotic twin pairs, where genetic and early-life influences were most tightly controlled, and for activities that were often cognitive and social in nature. Cognitive activity was particularly protective among monozygotic twin pairs carrying the apolipoprotein E epsilon4 allele, with a 30% risk reduction. Midlife physical activity did not modify dementia risk. Participation in a range of cognitively and socially engaging activities in midlife reduced risk for dementia and AD in twins discordant for onset, particularly among twin pairs at elevated genetic risk, and might be indicative of an enriched environment.

Genetic Influence on Contrast Sensitivity in Middle-Aged Male Twins

PubMed Central

Cronin-Golomb, Alice; Panizzon, Matthew S.; Lyons, Michael J.; Franz, Carol E.; Grant, Michael D.; Jacobson, Kristen C.; Eisen, Seth A.; Laudate, Thomas M.; Kremen, William S.

2007-01-01

Contrast sensitivity is strongly associated with daily functioning among older adults, but the genetic and environmental contributions to this ability are unknown. Using the classical twin method, we addressed this issue by examining contrast sensitivity at five spatial frequencies (1.5–18 cycles per degree) in 718 middle-aged male twins from the Vietnam Era Twin Study of Aging (VETSA). Heritability estimates were modest (14%–38%), whereas individual-specific environmental influences accounted for 62%–86% of the variance. Identifying the types of individual-specific events that impact contrast sensitivity may suggest interventions to modulate this ability and thereby improve overall quality of life as adults age. PMID:17604073

Genetic influence on contrast sensitivity in middle-aged male twins.

PubMed

Cronin-Golomb, Alice; Panizzon, Matthew S; Lyons, Michael J; Franz, Carol E; Grant, Michael D; Jacobson, Kristen C; Eisen, Seth A; Laudate, Thomas M; Kremen, William S

2007-07-01

Contrast sensitivity is strongly associated with daily functioning among older adults, but the genetic and environmental contributions to this ability are unknown. Using the classical twin method, we addressed this issue by examining contrast sensitivity at five spatial frequencies (1.5-18 cycles per degree) in 718 middle-aged male twins from the Vietnam Era Twin Study of Aging (VETSA). Heritability estimates were modest (14-38%), whereas individual-specific environmental influences accounted for 62-86% of the variance. Identifying the types of individual-specific events that impact contrast sensitivity may suggest interventions to modulate this ability and thereby improve overall quality of life as adults age.

A Possible Twin: The 1960s Twin Study Revisited/Twin Research: Twin-to-Twin Heart Transplantation; Distinguishing Monozygotic Twins; Twin Conceptions via Oocyte Donation; Factors Affecting Craniofacial Traits/In the Media: Triplet Delivery in the UK; Conjoined Twins and the Concept of Self; Colombian Twin Trainers; Skin Grafting to Save an Identical Co-Twin; Lack of Physical Flaws in Dolly the Cloned Sheep; Possible Conjoined Twins of Opposite-Sex; Passing of the Remaining Twin From the World's Longest Separated Pair.

PubMed

Segal, Nancy L

2018-04-01

This article begins with the story of a 51-year-old Los Angeles, California man, Justin Goldberg, whose daughter caught a glimpse of his striking look-alike at a popular market. Many people have so-called doppelgängers, but this occurrence is especially intriguing - the individual in question, born in New York City in the mid-1960s to an unwed mother, was an adoptee placed by the Louise Wise Adoption Agency. This agency, under the guidance of a prominent psychiatrist, decided to place twins in separate homes. Some of these twin children were part of a controversial child development study that was hidden from them and their parents. Next, recent and current twin research on heart transplantation, distinguishing monozygotic co-twins, twin conceptions via oocyte donation and factors affecting craniofacial traits are summarized. The article concludes with highlights on twins in the media, specifically, a triplet delivery in the United Kingdom, self-concept and consciousness in conjoined twins, Colombian twin trainers, skin grafting to save an identical co-twin, lack of physical flaws in Dolly the cloned sheep, possible opposite-sex conjoined twins, and the passing of the remaining twin from the world's longest separated pair.

Differential weight restoration on olanzapine versus fluoxetine in identical twins with anorexia nervosa.

PubMed

Duvvuri, Vikas; Cromley, Taya; Klabunde, Megan; Boutelle, Kerri; Kaye, Walter H

2012-03-01

No studies have compared the response to selective serotonin reuptake inhibitors and atypical antipsychotics in anorexia nervosa. This case study examines such a comparison. This report describes a case of 12-year-old identical twins with anorexia nervosa, one of whom was treated with olanzapine and the other with fluoxetine, while undergoing family therapy. Twin A treated with fluoxetine went from 75 to 84.4% ideal body weight, while Twin B treated with olanzapine went from 72 to 99.9% ideal body weight over the course of 9 months. This case supports the need for adequately powered, controlled clinical trials to test the efficacy of olanzapine in adolescents presenting with anorexia nervosa. Copyright © 2011 Wiley Periodicals, Inc.

Twins, Triplets, and Other Multiples

MedlinePlus

... one baby naturally. Another reason is that more women are using fertility treatments to help them conceive. How twins are formed Twins form in one of two ways: Identical twins occur when a single fertilized egg splits into two. Identical twins look ...

Smoking status and attractiveness among exemplar and prototypical identical twins discordant for smoking

PubMed Central

Woods, Andy; Stone, Christopher J.; Penton-Voak, Ian

2017-01-01

Smoking is associated with negative health of skin and increased signs of facial ageing. We aimed to address two questions about smoking and appearance: (1) does facial appearance alone provide an indication of smoking status, and (2) how does smoking affect the attractiveness of faces? We used faces of identical twins discordant for smoking, and prototypes made by averaging the faces of the twins. In Task 1, we presented exemplar twin sets and same sex prototypes side-by-side and participants (n = 590) indicated which face was the smoker. Participants were blind to smoking status. In Task 2 a separate sample (n = 580) indicated which face was more attractive. For the exemplar twin sets, there was inconclusive evidence participants selected the smoking twin as the smoker more often, or selected the non-smoking twin as the more attractive more often. For the prototypes, however, participants clearly selected the smoking prototypes as the smoker more often, and the non-smoking prototypes as the more attractive. Prototypical faces of smokers are judged more attractive and correctly identified as smokers more often than prototypical faces of matched non-smokers. We discuss the possible use of these findings in smoking behaviour change interventions. PMID:29308214

Ties of silence--Family lived experience of selective mutism in identical twins.

PubMed

Albrigtsen, Vårin; Eskeland, Benedicte; Mæhle, Magne

2016-04-01

This article is based on an in-depth interview with a pair of twins diagnosed with selective mutism and their parents 2 years after recovery. Selective mutism (SM) is a rare disorder, and identical twins sharing the condition are extremely rare. The twins developed SM simultaneously during their first year of school. The treatment and follow-up they received for several years are briefly described in this article. The interview explored the children's and their parents' narratives about the origin of the condition, the challenges it entailed in their daily lives, and what they found helpful in the treatment they were offered. In the interview, the children conveyed experiences that even the parents were unaware of and revealed examples of daily life-traumas for which they were unable to obtain support and help. The whole family was trapped in the silence. The twins and their parents emphasized different aspects in terms of what they believed were helpful. The implications of these findings for our understanding and treatment of children with SM are discussed, as well as the potential of service user involvement in child and adolescent mental health research. © The Author(s) 2015.

Heritability of usual alcohol intoxication and hangover in male twins: the NAS-NRC Twin Registry.

PubMed

Wu, Sheng-Hui; Guo, Qin; Viken, Richard J; Reed, Terry; Dai, Jun

2014-08-01

Alcohol consumption is influenced by heritable factors. The genetic influence on usual high-density drinking, including alcohol intoxication and hangover, is unknown. We aim to estimate the heritability of usual high-density drinking. A total of 13,511 male twins in this cross-sectional study were included from the National Academy of Sciences-National Research Council (NAS-NRC) Twin Registry. Data on the frequency of alcohol intoxication and alcohol hangover over the past year, that is, usual high-density drinking (phenotypes), were collected through a self-administered questionnaire when twins were middle-aged in 1972. Structural equation modeling was used to estimate the variance components of phenotypes. The mean of the frequency of usual high-density drinking in the entire twin population was 0.16 times per month for intoxication and 0.18 times per month for hangover. The heritability of usual alcohol intoxication was 50.7% (95% confidence interval [CI] 46.2 to 55.0) before and 49.9% (95% CI 45.3 to 54.2) after the body mass index (BMI) adjustment. The heritability of usual hangover was 55.4% (95% CI 51.2 to 58.6) before and 54.8% (95% CI 50.6 to 58.8) after adjustment for BMI. Unshared environmental factors between co-twins explained the remaining variance in alcohol intoxication and in hangover. Both genetic and unshared environmental factors have important influences on usual alcohol intoxication and hangover. These findings are important in understanding the occurrence of and developing interventions for usual high-density drinking. Copyright © 2014 by the Research Society on Alcoholism.

Adult body height of twins compared with that of singletons: a register-based birth cohort study of Norwegian males.

PubMed

Eriksen, Willy; Sundet, Jon M; Tambs, Kristian

2013-05-01

In the present study, we evaluated whether childhood differences in body height between singletons and twins persist into adulthood. Data from the Medical Birth Register of Norway were linked with data from the Norwegian National Conscript Service. This study used data on the 457,999 males who were born alive and without physical anomalies in single or twin births in Norway during 1967-1984 and who were examined at the mandatory military conscription (age 18-20 years; 1985-2003). For sibling comparisons, the authors selected the 1,721 sibships of full brothers that included at least 1 male born in a single birth and at least 1 male born in a twin birth (4,520 persons, including 2,493 twins and 2,027 singletons). An analysis of the total study population using generalized estimating equations showed that the twins were 0.6 cm (95% confidence interval: 0.4, 0.7) shorter than were the singletons after adjustment for a series of background factors. The fixed-effects regression analysis of the sibships that included both twins and singletons showed that the twins were 0.9 cm (95% confidence interval: 0.6, 1.2) shorter than were their singleton brothers. The study suggests that male twins born in Norway during 1967-1984 were slightly shorter in early adulthood than were singletons.

Identical twins concordant for pulmonary sequestration communicating with the esophagus and discordant for the VACTERL association.

PubMed

Becker, Julie; Hernandez, Ambrosio; Dipietro, Michael; Coran, Arnold G

2005-07-01

Communicating bronchopulmonary foregut malformations (CBPFMs) are unusual congenital structures composed of a segment of lung tissue connected to the foregut. We present what we believe is the first reported case of identical twins concordant for CBPFM who are discordant for the VACTERL association. Their nonfunctional lung tissue was successfully removed and the fistulae were corrected, and they are expected to live normal life spans. We review the literature concerning these malformations and the proposed theories of their etiology. This case report of concordance in identical twins suggests that a possible genetic component to CBPFMs cannot be ruled out. The discordance for the VACTERL association implies that the etiology is most likely multifactorial.

Poland's syndrome in one identical twin.

PubMed

Stevens, D B; Fink, B A; Prevel, C

2000-01-01

Female twins were evaluated at the Shriners Hospital in Lexington, Kentucky. One twin was normal, and the other twin had the classic findings of Poland's syndrome, manifested by absence of the pectoralis major and symbrachydactyly of the right upper extremity. Buccal smears from each child were submitted for DNA testing. The test confirmed monozygosity with 99.9% probability. Some previous reports have stated that Poland's syndrome is an autosomal dominant, genetically determined trait, whereas others have maintained that there is no genetic association. The original case described by Poland in 1841 was his cadaver, and no family history was reported. This twin study provides strong evidence that the condition is not determined by gene transmission.

Twins: A cloning experience.

PubMed

Prainsack, Barbara; Spector, Tim D

2006-11-01

Drawing upon qualitative interviews with monozygotic (identical) twins sharing 100% of their genes, and with dizygotic (fraternal) twins and singletons as control groups, this paper explores what it means to be genetically identical. (The twins interviewed were from the TwinsUK register in London.) In the context of the ongoing debate on human reproductive cloning, it examines questions such as: To what extent do identical twins perceive their emotional and physical bond to be a result of their genetic makeup? What would they think if they had been deliberately created genetically identical? How would they feel about being genetically identical to a person who was born a few years earlier or later? First, our respondents ascribed no great significance to the role of genes in their understanding of what it means to be identical twins. Second, the opinion that human reproductive cloning would "interfere with nature", or "contradict God's will", was expressed by our respondents exclusively on the abstract level. The more our respondents were able to relate a particular invented cloning scenario to their own life-worlds, the lower the prevalence of the argument. Third, for all three groups of respondents, the scenario of having been born in one of the other groups was perceived as strange. Fourth, the aspect that our respondents disliked about cloning scenarios was the potential motives of the cloners. Without equating monozygotic twins directly with "clones", these results from "naturally" genetically identical individuals add a new dimension to what a future cloning situation could entail: The cloned person might possibly (a) perceive a close physical and emotional connection to the progenitor as a blessing; (b) suffer from preconceptions of people who regard physical likeness as a sign of incomplete individuality; and (c) perceive the idea of not having been born a clone of a particular person as unpleasant.

Cancer risks in twins and singletons from twin and non-twin families.

PubMed

Chen, Lingjing; Cnattingius, Sven; Nyman Iliadou, Anastasia; Oberg, Anna Sara

2016-03-01

The unique intrauterine environment has been proposed to put twins at increased risk of certain cancers compared to singletons, still large population comparisons have generally indicated lower risks in twins. To improve the understanding of potential twin influence on cancer we compared twins to their singletons siblings, to target a unique twinning influence. Singletons from twin families were contrasted to singletons from non-twin families to further capture potential twin family influence on risk of cancer. Family relations were identified using the Swedish Multi-Generation Register. Among individuals born between 1932 and 1958, 49,156 twins and N = 35,227 singletons were identified from 18,098 unique twin families. All incident cases of specific cancer types were identified in the National Cancer Register up to the end of 2007. Standardized survival functions were estimated using weighted Cox proportional hazard regression and the corresponding cumulative risks plotted against age. Overall, primary cancers were identified in 9% and 18% of all male and female twins, compared to 11% and 19% of their male and female singleton siblings. When specific cancer sites were compared using standardized cumulative risk plots, no consistent statistically significant differences were noted either between twins and singletons of twin families or between singletons of twin and non-twin families. Despite a different intrauterine experience, twinning does not seem to have any greater negative influence on life-time risks of cancer. The findings also indicate that twin family membership has no substantial influence on cancer risks. © 2015 UICC.

Parenting and risk for mood, anxiety and substance use disorders: a study in population-based male twins.

PubMed

Otowa, Takeshi; Gardner, Charles O; Kendler, Kenneth S; Hettema, John M

2013-11-01

Previous studies consistently identified a relationship between parenting behavior and psychopathology. In this study, we extended prior analyses performed in female twins to a large sample of twins from male-male pairs. We used interview data on 2,609 adult male twins from a population-based twin registry. We examined the association between three retrospectively reported parenting dimensions (coldness, protectiveness, and authoritarianism) and lifetime history of seven common psychiatric and substance use disorders. Using univariate structural equation modeling, we also examined the influence of the genetic and environmental factors on parenting. Examined individually, coldness was consistently associated with risk for a broad range of adult psychopathology. Averaged odds of psychiatric disorders associated with parenting were increased between 26 and 36 %. When the three parenting dimensions were examined together, coldness remained significant for major depression, phobia, and generalized anxiety disorder. Controlling for other disorders, the associations between the parenting dimensions and psychopathology were non-specific. Twin fitting model demonstrated that modest heritability accounted for parenting, whereas most variance resulted from the non-shared environment. Based on our current and prior findings, there is broad similarity in the impact of parenting on adult psychopathology between men and women.

Molecular analysis of the gut microbiota of identical twins with Crohn's disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jansson, Janet; Dicksved, Johan; Halfvarson, Jonas

2008-03-14

Increasing evidence suggests that a combination of host genetics and the composition of the gut microbiota are important for development of Crohn's disease (CD). Our aim was to study identical twins with CD to determine microbial factors independently of host genetics. Fecal samples were studied from 10 monozygotic twin pairs with CD (discordant n=6, concordant n=4) and 8 healthy twin pairs. DNA was extracted, 16S rRNA genes were PCR amplified and T-RFLP fingerprints generated using general bacterial and Bacteroides group specific primers. The microbial communities were also profiled based on their % G+C contents. Bacteroides 16S rRNA genes were clonedmore » and sequenced from a subset of the samples. The bacterial diversity in each sample and similarity indices between samples were estimated based on the T-RFLP data using a combination of statistical approaches. Healthy individuals had a significantly higher bacterial diversity compared to individuals with CD. The fecal microbial communities were more similar between healthy twins than between twins with CD, especially when these were discordant for the disease. The microbial community profiles of individuals with ileal CD were significantly different from healthy individuals and those with colonic CD. Also, CD individuals had a lower relative abundance of B. uniformis and higher relative abundances of B. ovatus and B. vulgatus. Our results suggest that genetics and/or environmental exposure during childhood in part determine the gut microbial composition. However, CD is associated with dramatic changes in the gut microbiota and this was particularly evident for individuals with ileal CD.« less

Mixed-Handedness in Identical Twins Discordant for Combat Exposure in Vietnam: Relationship to Posttraumatic Stress Disorder.

PubMed

Goetz, Jared M; Pitman, Seth R; Tanev, Kaloyan S; Pitman, Roger K; Chemtob, Claude M

2016-01-01

This study evaluated the degree of mixed-handedness in predominantly right-handed Vietnam combat veteran twins and their identical, combat-unexposed cotwins. The "high-risk" cotwins of combat veterans with combat-related posttraumatic stress disorder (PTSD) had more mixed-handedness (i.e., less right-handedness) than the "low-risk" cotwins of combat veterans without PTSD. Self-reported combat exposure in combat-exposed twins was a mediator of the association between handedness in their unexposed cotwins and PTSD in the twins themselves. We conclude that mixed-handedness is a familial risk factor for combat-related PTSD. This risk may be mediated in part by a proclivity for mixed-handed soldiers and Marines to experience heavier combat.

[A 20-year follow-up study of a sample of 50 pairs of twins with neurotic-psychosomatic disorders].

PubMed

Muhs, A; Schepank, H; Manz, R

1990-01-01

As part of a research project, examination was made of a sample of 50 pairs of twins (21 pairs of identical twins, 16 pairs of non-identical twins of the same sex, and 13 pairs of male-female twins [n = 100 test persons]) between 1963 and 1969 and again recently after a period of 20 years. The index twins were drawn from among the patients who made use of the services of an out-patient psychotherapeutic clinic, and they were determined to be either psychoneurotic, character neurotic, or psychosomatically ill. The question examined was again one of nature vs. nurture. Identical twins showed a significantly higher similarity with regard to the seriousness of their neuroses and the manifestation of neurotic symptoms than did non-identical twins. Noticeable similarities existed in cases of depressive disturbances, disturbances of oral and aggressive behavior, and disturbances of interpersonal contact. With regard to the influence of variables in the environment, we examined the effect of factors in early childhood on neurotic development. Lack of a reference person, a negative attitude on the part of parents toward the child, etc., frustration within and outside the family have an effect on the manifestation of neuroses and on the course of their development. The influence of early childhood factors on the degree of neurotic disorder is still to be noted in the current point prevalence.

Effect of co-twin gender on neurodevelopmental symptoms: a twin register study.

PubMed

Eriksson, Jonna Maria; Lundström, Sebastian; Lichtenstein, Paul; Bejerot, Susanne; Eriksson, Elias

2016-01-01

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are neurodevelopmental disorders thought to have both genetic and environmental causes. It has been hypothesized that exposure to elevated levels of prenatal testosterone is associated with elevated traits of ASD and ADHD. Assuming that testosterone levels from a dizygotic male twin fetus may lead to enhanced testosterone exposure of its co-twins, we aimed to test the prenatal testosterone hypothesis by comparing same-sex with opposite-sex dizygotic twins with respect to neurodevelopmental symptoms. Neuropsychiatric traits were assessed in a population-based twin cohort from the Child and Adolescent Twin Study in Sweden (CATSS). Parental interviews were conducted for 16,312 dizygotic twins, 9 and 12 years old, with the Autism-Tics, ADHD, and other Comorbidities inventory (A-TAC). Girls with a female co-twin had an increased risk of reaching the cut-off score for ADHD compared with girls with a male co-twin. Both boys and girls with a female co-twin displayed a larger number of traits related to attention deficit and repetitive and stereotyped behaviors than those with a male twin. In girls, this also extended to social interaction and the combined measures for ASD and ADHD, however, with small effect sizes. Our results are reverse to what would have been expected from the prenatal testosterone hypothesis but consistent with a previous study of ASD and ADHD traits in dizygotic twins. The seemingly protective effect for girls of having a twin brother may be an effect of parent report bias, but may also be an unexpected effect of sharing the intrauterine environment with a male co-twin.

Effects of social contact and zygosity on 21-y weight change in male twins.

PubMed

McCaffery, Jeanne M; Franz, Carol E; Jacobson, Kristen; Leahey, Tricia M; Xian, Hong; Wing, Rena R; Lyons, Michael J; Kremen, William S

2011-08-01

Recent evidence indicates that social contact is related to similarities in weight gain over time. However, no studies have examined this effect in a twin design, in which genetic and other environmental effects can also be estimated. We determined whether the frequency of social contact is associated with similarity in weight change from young adulthood (mean age: 20 y) to middle age (mean age: 41 y) in twins and quantified the percentage of variance in weight change attributable to social contact, genetic factors, and other environmental influences. Participants were 1966 monozygotic and 1529 dizygotic male twin pairs from the Vietnam-Era Twin Registry. Regression models tested whether frequency of social contact and zygosity predicted twin pair similarity in body mass index (BMI) change and weight change. Twin modeling was used to partition the percentage variance attributable to social contact, genetic, and other environmental effects. Twins gained an average of 3.99 BMI units, or 13.23 kg (29.11 lb), over 21 y. In regression models, both zygosity (P < 0.001) and degree of social contact (P < 0.02) significantly predicted twin pair similarity in BMI change. In twin modeling, social contact between twins contributed 16% of the variance in BMI change (P < 0.001), whereas genetic factors contributed 42%, with no effect of additional shared environmental factors (1%). Similar results were obtained for weight change. Frequency of social contact significantly predicted twin pair similarity in BMI and weight change over 21 y, independent of zygosity and other shared environmental influences.

Identical Twins Raised Apart

ERIC Educational Resources Information Center

Farnsworth, David L.

2015-01-01

This article describes a bivariate data set that is interesting to students. Indeed, this particular data set, which involves twins and IQ, has sparked more student interest than any other set that I have presented. Specific uses of the data set are presented.

African American Male Student-Athletes: Identity and Academic Performance

ERIC Educational Resources Information Center

O'Brien, Kathryn Mary

2012-01-01

The purpose of the current research was to examine racial, male and athletic identities and their individual and collective impact on the academic performance of African American male Division I student-athletes (AAMSAs). Data was collected using the Multidimensional Inventory of Black Identity (MIBI), the Male Role Norms Scale (MRNS), and the…

Stolen twin: fascination and curiosity/twin research reports: evolution of sleep length; dental treatment of craniopagus twins; cryopreserved double embryo transfer; gender options in multiple pregnancy/current events: appendectomy in one twin; autistic twin marathon runners; 3D facial recognition; twin biathletes.

PubMed

Segal, Nancy L

2014-02-01

The story of her allegedly stolen twin brother in Armenia is recounted by a 'singleton twin' living in the United States. The behavioral consequences and societal implications of this loss are considered. This case is followed by twin research reports on the evolution of sleep length, dental treatment of craniopagus conjoined twins, cryopreserved double embryo transfer (DET), and gender options in multiple pregnancy. Current events include the diagnosis of appendectomy in one identical twin, the accomplishments of autistic twin marathon runners, the power of three-dimensional (3D) facial recognition, and the goals of twin biathletes heading to the 2014 Sochi Olympics in Russia.

An Investigation of Exceptional Twins.

ERIC Educational Resources Information Center

Crismore, Avon

The author, herself a mother of twins, reviews research on exceptional twins. She considers reasons for fascination with twins and comments upon important advances in technology. Current research in Indianapolis to measure cognitive, perceptual, personality, and chromosome patterns of twins is described. Differences in the makeup of identical and…

The USC Adult Twin Cohorts: International Twin Study and California Twin Program.

PubMed

Cozen, Wendy; Hwang, Amie E; Cockburn, Myles G; Hamilton, Ann S; Zadnick, John; Mack, Thomas M

2013-02-01

The study of twin subjects permits the documentation of crude heritability and may promote the identification of specific causal alleles. We believe that at the current time, the chief research advantage of twins as subjects, especially monozygotic twins, is that the commonality of their genetic and cultural identity simplifies the interpretation of biological associations. In order to study genetic and environmental determinants of cancer and chronic diseases, we developed two twin registries, maintained at the University of Southern California: The International Twin Study (ITS) and the California Twin Program (CTP). The ITS is a volunteer registry of twins with cancer and chronic disease consisting of 17,245 twin pairs affected by cancer and chronic disease, respectively, ascertained by advertising in periodicals from 1980-1991. The CTP is a population-based registry of California-born twin pairs ascertained by linking the California birth records to the State Department of Motor Vehicles. Over 51,000 individual California twins representing 36,965 pairs completed and returned 16-page questionnaires. Cancer diagnoses in the California twins are updated by regular linkage to the California Cancer Registry. Over 5,000 cancer patients are represented in the CTP. Twins from both registries have participated extensively in studies of breast cancer, melanoma, lymphoma, multiple sclerosis, systemic lupus erythematosus, diabetes mellitus type 1, mammographic density, smoking, and other traits and conditions.

A Computational Discriminability Analysis on Twin Fingerprints

NASA Astrophysics Data System (ADS)

Liu, Yu; Srihari, Sargur N.

Sharing similar genetic traits makes the investigation of twins an important study in forensics and biometrics. Fingerprints are one of the most commonly found types of forensic evidence. The similarity between twins’ prints is critical establish to the reliability of fingerprint identification. We present a quantitative analysis of the discriminability of twin fingerprints on a new data set (227 pairs of identical twins and fraternal twins) recently collected from a twin population using both level 1 and level 2 features. Although the patterns of minutiae among twins are more similar than in the general population, the similarity of fingerprints of twins is significantly different from that between genuine prints of the same finger. Twins fingerprints are discriminable with a 1.5%~1.7% higher EER than non-twins. And identical twins can be distinguished by examine fingerprint with a slightly higher error rate than fraternal twins.

Parenting and risk for mood, anxiety and substance use disorders: a study in population-based male twins

PubMed Central

Gardner, Charles O.; Kendler, Kenneth S.; Hettema, John M.

2013-01-01

Background Previous studies consistently identified a relationship between parenting behavior and psychopathology. In this study, we extended prior analyses performed in female twins to a large sample of twins from male–male pairs. Methods We used interview data on 2,609 adult male twins from a population-based twin registry. We examined the association between three retrospectively reported parenting dimensions (coldness, protectiveness, and authoritarianism) and lifetime history of seven common psychiatric and substance use disorders. Using univariate structural equation modeling, we also examined the influence of the genetic and environmental factors on parenting. Results Examined individually, coldness was consistently associated with risk for a broad range of adult psychopathology. Averaged odds of psychiatric disorders associated with parenting were increased between 26 and 36 %. When the three parenting dimensions were examined together, coldness remained significant for major depression, phobia, and generalized anxiety disorder. Controlling for other disorders, the associations between the parenting dimensions and psychopathology were non-specific. Twin fitting model demonstrated that modest heritability accounted for parenting, whereas most variance resulted from the non-shared environment. Conclusions Based on our current and prior findings, there is broad similarity in the impact of parenting on adult psychopathology between men and women. PMID:23344783

Male gender identity in complete androgen insensitivity syndrome.

PubMed

T'Sjoen, Guy; De Cuypere, Griet; Monstrey, Stan; Hoebeke, Piet; Freedman, F Kenneth; Appari, Mahesh; Holterhus, Paul-Martin; Van Borsel, John; Cools, Martine

2011-06-01

Women and girls with complete androgen insensitivity syndrome (CAIS) invariably have a female typical core gender identity. In this case report, we describe the first case of male gender identity in a CAIS individual raised female leading to complete sex reassignment involving both androgen treatment and phalloplasty. CAIS was diagnosed at age 17, based on an unambiguously female phenotype, a 46,XY karyotype, and a 2660delT androgen receptor (AR) gene mutation, leading to a premature stop in codon 807. Bilateral gonadectomy was performed but a short period of estrogen treatment induced a negative emotional reaction and treatment was stopped. Since the age of 3, childhood-onset cross gender behavior had been noticed. After a period of psychotherapy, persisting male gender identity was confirmed. There was no psychiatric co-morbidity and there was an excellent real life experience. Testosterone substitution was started, however without inducing any of the desired secondary male characteristics. A subcutaneous mastectomy was performed and the patient received phalloplasty by left forearm free flap and scrotoplasty. Testosterone treatment was continued, without inducing virilization, and bone density remained normal. The patient qualifies as female-to-male transsexual and was treated according to the Standards of Care by the World Professional Association for Transgender Health with good outcome. However, we do not believe that female sex of rearing as a standard procedure should be questioned in CAIS. Our case challenges the role of a functional AR pathway in the development of male gender identity.

Twin Research and the Arts: Interconnections / Twin Research: Twin Studies of Sexual Orientation; A Historical Biological Twin Gem; GWAS Approach to Who Has Twins / Newsworthy: Twins on College Campuses; 'Brainprint': Personal Identification by Brain Waves.

PubMed

Segal, Nancy L

2016-08-01

The interrelatedness between twin research and the arts is explored via a new play about a famous case. In the 1960s, identical twin David Bruce Reimer was accidentally castrated as an infant during circumcision to correct a urinary problem. The decision to raise him as a girl, and the consequences of that decision, are explored in the new theatrical production of Boy. Other examples of the arts mirroring science, and vice versa, are described. Next, brief reviews and summaries of twin research on sexual orientation, 1860s' knowledge of placental arrangements and twinning mechanisms, and genes underlying multiple birth conception and fertility related measures are provided. This article concludes with a look at twins on college campuses and the identification of individuals by their brain waves. A correction and clarification regarding my article on the Brazilian Twin Registry in the last issue of THG (Segal, 2016) is also provided.

The twin children of Auschwitz-Birkenau: conference on Nazi medicine.

PubMed

Segal, Nancy L

2013-06-01

The twin children who survived the Holocaust and the horrific medical experiments conducted by Nazi doctors are sometimes overlooked in the relevant literature. This topic and more were discussed as part of an annual conference hosted by students from Yeshiva University's Medical Ethics Society in October 2012. A selective summary of this meeting is followed by summaries of recent twin studies concerning genetic influences on twinning, in vitro fertilization versus spontaneous twin pregnancies, gender identity disorder, and royal support for twin registries. Several human interest stories are also worth noting. They include identical twin school principals, twin loss at Sandy Hook Elementary School, timely twin documentaries, new twin and twin-like reunions, and the passing of two prominent twins.

Latino Male College Students' Identities, Psychological Stress, and Coping Mechanisms

ERIC Educational Resources Information Center

Ramirez, Ana E.

2017-01-01

Latino male college students' identities impact their personal experiences, academic achievement, and well-being. This qualitative study uses a narrative inquiry approach to research Latino male college students' racial and ethnic, gender, and academic identities and to investigate how these identities impact their psychological stress and the…

[Influences of genetic and environmental factors on smoking related behaviors among male twin adults in China].

PubMed

Bao, Z Q; Yu, C Q; Wang, B Q; Cao, W H; Gao, W J; Lyu, J; Wang, S F; Pang, Z C; Cong, L M; Dong, Z; Wu, F; Wang, H; Wu, X P; Wang, D Z; Wang, X J; Wang, B Y; Li, L M

2016-05-01

To analyze the influences of genetic and environmental factors on smoking behavior, smoking cessation and onset age of smoking less than 20 years in male twin adults. A face-to-face questionnaire was conducted to collect data from 6 458 pair male twins aged ≥25 years registered in 9 provinces(municipality)in China. The heritability of three smoking related behaviors were calculated by using structural equation models. The ACE models were the best models of the three dimensions of smoking, i.e. smoking behavior, smoking cessation and onset age of smoking less than 20 years for male twins, and the corresponding heritability of these behaviors were 0.26(0.19-0.34), 0.27(0.19-0.37)and 0.05(0.00-0.14), respectively. When adjusted for area and age, the heritability of these three behaviors were 0.26(0.19-0.34), 0.31(0.00-0.74)and 0.05(0.00-0.14), respectively. All the three smoking related behaviors were affected by genetic factors, but environment factors had more effect on them. For smoking cessation, the heritability was highest, but the influence of environmental factors was lowest. Meanwhile, for onset age of smoking, the influence of environmental factors was highest.

Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

PubMed

Segal, Nancy L

2016-06-01

The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel.

Genetic influences on alcohol use behaviors have diverging developmental trajectories: a prospective study among male and female twins.

PubMed

Meyers, Jacquelyn L; Salvatore, Jessica E; Vuoksimaa, Eero; Korhonen, Tellervo; Pulkkinen, Lea; Rose, Richard J; Kaprio, Jaakko; Dick, Danielle M

2014-11-01

Both alcohol-specific genetic factors and genetic factors related to externalizing behavior influence problematic alcohol use. Little is known, however, about the etiologic role of these 2 components of genetic risk on alcohol-related behaviors across development. Prior studies conducted in a male cohort of twins suggest that externalizing genetic factors are important for predicting heavy alcohol use in adolescence, whereas alcohol-specific genetic factors increase in importance during the transition to adulthood. In this report, we studied twin brothers and sisters and brother-sister twin pairs to examine such developmental trajectories and investigate whether sex and cotwin sex effects modify these genetic influences. We used prospective, longitudinal twin data collected between ages 12 and 22 within the population-based FinnTwin12 cohort study (analytic n = 1,864). Our dependent measures of alcohol use behaviors included alcohol initiation (age 12), intoxication frequency (ages 14 and 17), and alcohol dependence criteria (age 22). Each individual's genetic risk of alcohol use disorders (AUD-GR) was indexed by his/her parents' and cotwin's DSM-IV Alcohol Dependence (AD) criterion counts. Likewise, each individual's genetic risk of externalizing disorders (EXT-GR) was indexed with a composite measure of parents' and cotwin's DSM-IV Conduct Disorder and Antisocial Personality Disorder criterion counts. EXT-GR was most strongly related to alcohol use behaviors during adolescence, while AUD-GR was most strongly related to alcohol problems in young adulthood. Further, sex of the twin and sex of the cotwin significantly moderated the associations between genetic risk and alcohol use behaviors across development: AUD-GR influenced early adolescent alcohol use behaviors in females more than in males, and EXT-GR influenced age 22 AD more in males than in females. In addition, the associations of AUD-GR and EXT-GR with intoxication frequency were greater among 14- and

Longitudinal weight differences, gene expression, and blood biomarkers in BMI discordant identical twins

PubMed Central

van Dongen, Jenny; Willemsen, Gonneke; Heijmans, Bastiaan T.; Neuteboom, Jacoline; Kluft, Cornelis; Jansen, Rick; Penninx, Brenda W.J.; Slagboom, P. Eline; de Geus, Eco J.C.; Boomsma, Dorret I.

2015-01-01

BMI discordance is uncommon in adolescent identical pairs but increases with higher pair-mean of BMI at older ages, although long-term BMI discordance is rare. In discordant pairs, the heavier twin had a more unfavorable blood biomarker profile than the genetically matched leaner twin, in support of causal effects of obesity. PMID:25765203

Genetic and environmental contributions to age of onset of alcohol dependence symptoms in male twins.

PubMed

Liu, I-Chao; Blacker, Deborah L; Xu, Ronghui; Fitzmaurice, Garrett; Tsuang, Ming T; Lyons, Michael J

2004-11-01

To investigate genetic and environmental influences on the development of specific alcohol dependence symptoms. A classical twin study of 3372 male-male twin pairs in the Vietnam Era Twin (VET) Registry based on telephone interviews about alcohol use. The nine diagnostic symptoms according to the Diagnostic and Statistical Manual of Mental Disorder, version III (revised) (DSM-III-R) definition of alcohol dependence. Symptoms were grouped into those based on impaired control, biological effects and social consequences (Beresford's classification) or early versus late symptoms (Nelson's classification). Survival models with random effects were used to examine the age of onset of each symptom. Approximately 38% of the variation in age of onset of each symptom group based on Beresford's classification is due to additive genetic factors. The age of onset of late symptoms from Nelson's classification appears to be most affected by genetic factors. Estimates of genetic effects for impaired control symptoms are greatly decreased when twins with comorbid psychiatric disorders are excluded. Our results support the heritability of age of onset of DSM-III-R-defined symptoms for alcohol dependence. However, no symptom group in Beresford's classification could be identified as more heritable than other symptom groups. A strong association between genetic vulnerability and co-occurring diseases for symptoms indicative of impaired control could be found. In addition, our findings show that the late symptom group could be a good candidate for subsequent genetic research.

Male identity in mental health nursing.

PubMed

Holyoake, Dean-David

To explore the cultural meaning associated with male mental health nurses. An ethnographic approach was used to discover the meaning informants attach to the cultural norms, values and rules that govern their behaviour. Data were collected through participant observation and in-depth interviews with informants. Data were analysed using emerging domains and taxonomies regarding male nurse issues. This involved grouping terms, words and everyday reflections collected from the male mental health nurses. These lists of data (taxonomies) enabled the researcher to identify in-depth cultural themes about the attitudes, behaviours and symbolism typically associated with male nurses. A number of cultural themes emerged, including the notion of 'soft masculinity', which provided some insight into male nurses' experiences of working in a female-dominated workplace. A recurring theme was the need for male nurses to demonstrate gentleness and caring while maintaining a balanced sense of masculine identity.

Twin-singleton differences in intelligence: a register-based birth cohort study of Norwegian males.

PubMed

Eriksen, Willy; Sundet, Jon M; Tambs, Kristian

2012-10-01

The aim was to determine the difference in intelligence between singletons and twins in young adulthood. Data from the Medical Birth Register of Norway were linked with register data from the Norwegian National Conscript Service. The study base consisted of data on the 445,463 males who were born alive in either single or twin births in Norway during 1967-1984 and who were examined at the time of the mandatory military conscription (age 18-20). Within this study base, there were data on 1,653 sibships of full brothers that included at least one man born in single birth and at least one man born in twin birth (4,307 persons, including 2,378 twins and 1,929 singletons). The intelligence scores of the singletons were 11% (95% confidence interval [CI]: 9-14%) of a standard deviation higher than those of the twins, after adjustment for birth year, birth order, parental ages at delivery, parental education levels, and other factors. The adjusted within-family difference was also 11% (95 % CI: 6-16%) of a standard deviation, indicating that unmeasured factors shared by siblings (e.g., maternal body height) have not influenced the estimate in important ways. When gestational age at birth was added to the model, the estimate for the difference in intelligence score was approximately the same. Including birth weight in the model strongly reduced the estimate. In conclusion, twins born in Norway during 1967-1984 had slightly lower intelligence in early adulthood compared with the singletons.

ETV6-RUNX1 + Acute Lymphoblastic Leukaemia in Identical Twins.

PubMed

Ford, Anthony M; Greaves, Mel

2017-01-01

Acute leukaemia is the major subtype of paediatric cancer with a cumulative risk of 1 in 2000 for children up to the age of 15 years. Childhood acute lymphoblastic leukaemia (ALL) is a biologically and clinically diverse disease with distinctive subtypes; multiple chromosomal translocations exist within the subtypes and each carries its own prognostic relevance. The most common chromosome translocation observed is the t(12;21) that results in an in-frame fusion between the first five exons of ETV6 (TEL) and almost the entire coding region of RUNX1 (AML1).The natural history of childhood ALL is almost entirely clinically silent and is well advanced at the point of diagnosis. It has, however, been possible to backtrack this process through molecular analysis of appropriate clinical samples: (i) leukaemic clones in monozygotic twins that are either concordant or discordant for ALL; (ii) archived neonatal blood spots or Guthrie cards from individuals who later developed leukaemia; and (iii) stored, viable cord blood cells.Here, we outline our studies on the aetiology and pathology of childhood ALL that provide molecular evidence for a monoclonal, prenatal origin of ETV6-RUNX1+ leukaemia in monozygotic identical twins. We provide mechanistic support for the concept that altered patterns of infection during early childhood can deliver the necessary promotional drive for the progression of ETV6-RUNX1+ pre-leukaemic cells into a postnatal overt leukaemia.

Epigenetic discrimination of identical twins from blood under the forensic scenario.

PubMed

Vidaki, Athina; Díez López, Celia; Carnero-Montoro, Elena; Ralf, Arwin; Ward, Kirsten; Spector, Timothy; Bell, Jordana T; Kayser, Manfred

2017-11-01

Monozygotic (MZ) twins share the same STR profile, demonstrating a practical problem in forensic casework. DNA methylation has provided a suitable resource for MZ twin differentiation; however, studies addressing the forensic feasibility are lacking. Here, we investigated epigenetic MZ twin differentiation from blood under the forensic scenario comprising i) the discovery of candidate markers in reference-type blood DNA via genome-wide analysis, ii) the technical validation of candidate markers in reference-type blood DNA using a suitable targeted method, and iii) the analysis of the validated markers in trace-type DNA. Genome-wide methylation analysis in blood DNA from 10 MZ twin pairs resulted in 19-111 twin-differentially methylated sites (tDMSs) per pair with >0.3 twin-to-twin differences. Considering all top three candidate tDMSs across all pairs in the technical validation based on methylation-specific qPCR, 67.85% generated >0.1 twin-to-twin differences. Of the validated tDMSs, 68.4% showed >0.1 twin-to-twin differences with qPCR in trace-type DNA across 8 pairs. Using an updated marker selection strategy, 8 additional candidate tDMSs were obtained for an example MZ pair, of which 7 showed >0.1 twin-to-twin differences in both reference- and trace-type DNA. Lastly, we introduce a high-resolution melting curve analysis of the entire fragment that can complement the proposed approach. Overall, our study demonstrates the general feasibility of epigenetic twin differentiation in the forensic context and highlights that the number of informative tDMSs in the final trace DNA analysis is crucial, as some candidate markers identified in reference DNA were shown not informative in the trace DNA due to various, including technical, reasons. Future studies will need to address the optimal number of epigenetic markers required for reliable identification of MZ twin individuals including statistical considerations. Copyright © 2017 Elsevier B.V. All rights reserved.

Stress and Identity among Black Males.

ERIC Educational Resources Information Center

Stokes, DeVon R.

Twenty Black American males' reactions to slides depicting interracial climate and/or racial oppression were investigated by recording physiological responses, specifically, galvanic skin potential (GSP) and heart rate (HR). Participants were also given the Myers/Stokes Identity Scale (MSIS) to ascertain their reaction to oppression and, based on…

Male Archetypes as Resources for Homosexual Identity Development in Gay Men.

ERIC Educational Resources Information Center

McFarland, William P.; McMahon, Timothy R.

1999-01-01

The male archetypes of king, lover, magician, and warrior provide important and timeless insights into mature masculine qualities. Homosexual identity development models describe tasks that confront gay men as they move through the identity development process. Proposes that by understanding the metaphor of male archetypes, gay men will discover…

Genetic and environmental effects on age at menarche, and its relationship with reproductive health in twins.

PubMed

Jahanfar, Shayesteh; Lye, Munn-Sann; Krishnarajah, Isthrinayagy S

2013-04-01

Menarche or first menstrual period is a landmark in reproductive life span and it is the most prominent change of puberty. The timing of menarche can be under the influence of genes as well as individual environmental factors interacting with genetic factors. Our study objectives were (a) to investigate the heritability of age of menarche in twins, (b) to obtain the association between age of menarche and childhood factors, and reproductive events/behavior, (c) to examine whether or not having a male co-twin affects early/late menarche. A group of female-female identical (n = 108, 54 pairs), non-identical twins (n = 68, 34 pairs) and 17 females from opposite-sex twin sets were identified from twin registries of Malaysia and Iran. Genetic analysis was performed via two methods of Falconers' formula and maximum likelihood. Heritability was found to be 66% using Falconers' formula and 15% using univariate twin analysis. Model analysis revealed that shared environmental factors have a major contribution in determining the age of menarche (82%) followed by non-shared environment (18%). Result of this study is consistent with that of the literature. Timing of menarche could be under the influence of shared and non-shared environmental effects. Hirsutism was found to have a higher frequency among subjects with late menarche. There was no significant difference in age of menarche between females of opposite-sex twins and females of same-sex twins. It is concluded that twin models provide a powerful means of examining the total genetic contribution to age of menarche. Longitudinal studies of twins may clarify the type of environmental effects that determine the age of menarche.

Masculinity Identity Development and Its Relevance to Supporting Talented Black Males

ERIC Educational Resources Information Center

Henfield, Malik S.

2012-01-01

The purpose of the article is to provide a brief introduction to Black male masculine identity development and relate it to the field of gifted education. It will begin with information related to identity development that is applicable to Black males. Next, the phenomenological variant of ecological systems theory (PVEST) will be explored and…

Attractiveness Differences Between Twins Predicts Evaluations of Self and Co-Twin

PubMed Central

Principe, Connor P.; Rosen, Lisa H.; Taylor-Partridge, Teresa; Langlois, Judith H.

2012-01-01

One of the most consistent findings in psychology shows that people prefer and make positive attributions about attractive compared with unattractive people. The goal of the current study was to determine the power of attractiveness effects by testing whether these social judgments are made where attractiveness differences are smallest: between twins. Differences in facial attractiveness predicted twins’ evaluations of self and their co-twin (n = 158; 54 male). In twin pairs, the more attractive twin judged their less attractive sibling as less physically attractive, athletic, socially competent, and emotionally stable. The less attractive twin did the reverse. Given that even negligible differences in facial attractiveness predicted self and co-twin attitudes, these results provide the strongest test yet of appearance-based stereotypes. PMID:23467329

Epigenetic supersimilarity of monozygotic twin pairs

USDA-ARS?s Scientific Manuscript database

Monozygotic twins have long been studied to estimate heritability and explore epigenetic influences on phenotypic variation. The phenotypic and epigenetic similarities of monozygotic twins have been assumed to be largely due to their genetic identity. Here, by analyzing data from a genome-scale stud...

Supine Lower Body Negative Pressure Exercise Maintains Upright Exercise Capacity in Male Twins during 30 Days of Bed Rest

NASA Technical Reports Server (NTRS)

Lee, Stuart M. C.; Schneider, Suzanne M.; Boda, Wanda L.; Watenpaugh, Donald E.; Macias, Brandon R.; Meyer, R. Scott; Hargens, Alan R.

2006-01-01

Exercise capacity is reduced following both short and long duration exposures to microgravity. We have shown previously that supine lower body negative pressure with exercise (LBNP(sub ex) maintains upright exercise capacity in men after 5d and 15d bed rest, as a simulation of microgravity. We hypothesized that LBNP(sub ex) would protect upright exercise capacity (VO2pk) and sprint performance in eight sets of identical male twins during a 30-d bed rest. Twins within each set were randomly assigned to either a control group (CON) who performed no exercise or to an exercise group (EX) who performed a 40-min interval (40-80% pre-BR VO2pk) LBNP(sub ex) (55+/-4 mmHg) exercise protocol, plus 5 min of resting LBNP, 6 d/wk. LBNP produced footward force equivalent to 1.0- 1.2 times body weight. Pre- and post-bed rest, subjects completed an upright graded exercise test to volitional fatigue and sprint test of 30.5 m. After bed rest, VO2pk was maintained in the EX subjects (-3+/-3%), but was significantly decreased in the CON subjects (-24+/-4%). Sprint time also was increased in the CON subjects (24+/-8%), but maintained in the EX group (8+/-2%). The performance of a supine, interval exercise protocol with LBNP maintains upright exercise capacity and sprint performance during 30 d of bed rest. This exercise countermeasure protocol may help prevent microgravity-induced deconditioning during long duration space flight.

Spiritual Identity in Israeli Religious Male Adolescents: Observations and Educational Implications

ERIC Educational Resources Information Center

Fisherman, Shraga

2002-01-01

Based on Herbert's (1987) theory of ego identity development and on interviews of hundreds of Israeli religious male adolescents and young adults who were raised and educated in religious society and later left the fold, this article presents a model of development of religious identity. Three levels of religious identity development--healthy,…

The Influence of Social Media Use on Male College Students' Gender Identity and Gendered Performance

ERIC Educational Resources Information Center

Potts, Lawrence Charles

2017-01-01

To better understand the influence of social media use on male college students' gender identity and male gendered performance, this research examined existing research on digital identity and social networking sites, male gender identity development, college student development theory, and the effects of living arrangements on college students.…

Higher Incidence of Hypospadias in Monochorionic Twins.

PubMed

Visser, Remco; Burger, Nienke C M; van Zwet, Erik W; Hilhorst-Hofstee, Yvonne; Haak, Monique C; van den Hoek, Joop; Oepkes, Dick; Lopriore, Enrico

2015-10-01

Hypospadias is associated with twinning. The incidence of hypospadias in monochorionic and dichorionic male twins is, however, yet to be determined. All medical records of monochorionic and dichorionic twins admitted to our neonatal nursery between January 2004 and August 2013 were reviewed for the presence of hypospadias. A total of 350 monochorionic and 303 dichorionic male twins were included in the study. The incidence of hypospadias in monochorionic and dichorionic groups was 4% (14/350) and 1% (3/303) (p = .016) respectively. In 11 of the 15 twin couples, hypospadias occurred in the twin with the lowest birth weight. The rate of hypospadias in twin infants small-for-gestational-age group was 10% (6/60) compared with 2% (11/593) in the appropriate-for-gestational-age group (p = .002). In a multivariate analysis, both monochorionicity and small-for-gestational-age were independently associated with hypospadias, odds ratio 4.1 (95% confidence interval (CI): 1.1-14.7) and 6.1 (95% CI: 2.2-17.2) respectively. The incidence of hypospadias is four-fold higher in monochorionic twins compared with dichorionic twins. Hypospadias is also independently associated with small-for-gestational-age.

Environmental and Genetic Contributions to Indicators of Oral Malodor in Twins

PubMed Central

Bretz, Walter A.; Biesbrock, A.; Corby, P. M; Corby, A. L.; Bretz, W. G.; Wessel, J.; Schork, N. J.

2011-01-01

This study aimed to: (1) determine concordance rates of self-reported and subjectively determined indicators of oral malodor in twins; (2) determine the relative contributions of genetic and environmental factors to levels of volatile sulfur compounds (VSCs) in intraoral and exhaled breath. Fifty-one twin pairs participated in the study. Measurements of VSCs were obtained by a halimeter. The presence of tongue coatings was determined and twins filled out a 32-item questionnaire on oral malodor indicators independently of one another. Estimates of heritability (h2) for halimeter measurements were computed by SOLAR. The concordance rates for the presence of tongue coating among identical and fraternal twins were 67% and 11%, respectively. In the 10 most informative items, 70% exhibited higher concordance rates for identical than for fraternal twins. Of particular interest were the differences in concordance rates for dry mouth, sinus infection and unusual sweating. The h2 for intraoral breath was 0.28 ± 0.17 (NS), whereas the h2 for exhaled breath was 0.50 ± 0.20 (p = .0207). The concordance rates of tongue coatings and malodor indicators were higher in identical twins than in fraternal twins. Intraoral breath VSC values were primarily attributable to environmental factors, whereas exhaled breath VSC values were partially explained by genetic factors. PMID:22506313

Perception of Male Caller Identity in Koalas (Phascolarctos cinereus): Acoustic Analysis and Playback Experiments

PubMed Central

Charlton, Benjamin D.; Ellis, William A. H.; McKinnon, Allan J.; Brumm, Jacqui; Nilsson, Karen; Fitch, W. Tecumseh

2011-01-01

The ability to signal individual identity using vocal signals and distinguish between conspecifics based on vocal cues is important in several mammal species. Furthermore, it can be important for receivers to differentiate between callers in reproductive contexts. In this study, we used acoustic analyses to determine whether male koala bellows are individually distinctive and to investigate the relative importance of different acoustic features for coding individuality. We then used a habituation-discrimination paradigm to investigate whether koalas discriminate between the bellow vocalisations of different male callers. Our results show that male koala bellows are highly individualized, and indicate that cues related to vocal tract filtering contribute the most to vocal identity. In addition, we found that male and female koalas habituated to the bellows of a specific male showed a significant dishabituation when they were presented with bellows from a novel male. The significant reduction in behavioural response to a final rehabituation playback shows this was not a chance rebound in response levels. Our findings indicate that male koala bellows are highly individually distinctive and that the identity of male callers is functionally relevant to male and female koalas during the breeding season. We go on to discuss the biological relevance of signalling identity in this species' sexual communication and the potential practical implications of our findings for acoustic monitoring of male population levels. PMID:21633499

Multiple pathways to identification: exploring the multidimensionality of academic identity formation in ethnic minority males.

PubMed

Matthews, Jamaal S

2014-04-01

Empirical trends denote the academic underachievement of ethnic minority males across various academic domains. Identity-based explanations for this persistent phenomenon describe ethnic minority males as disidentified with academics, alienated, and oppositional. The present work interrogates these theoretical explanations and empirically substantiates a multidimensional lens for discussing academic identity formation within 330 African American and Latino early-adolescent males. Both hierarchical and iterative person-centered methods were utilized and reveal 5 distinct profiles derived from 6 dimensions of academic identity. These profiles predict self-reported classroom grades, mastery orientation, and self-handicapping in meaningful and varied ways. The results demonstrate multiple pathways to motivation and achievement, challenging previous oversimplified stereotypes of marginalized males. This exploratory study triangulates unique interpersonal and intrapersonal attributes for promoting healthy identity development and academic achievement among ethnic minority adolescent males.

Global identification predicts gay-male identity integration and well-being among Turkish gay men.

PubMed

Koc, Yasin; Vignoles, Vivian L

2016-12-01

In most parts of the world, hegemonic masculinity requires men to endorse traditional masculine ideals, one of which is rejection of homosexuality. Wherever hegemonic masculinity favours heterosexuality over homosexuality, gay males may feel under pressure to negotiate their conflicting male gender and gay sexual identities to maintain positive self-perceptions. However, globalization, as a source of intercultural interaction, might provide a beneficial context for people wishing to create alternative masculinities in the face of hegemonic masculinity. Hence, we tested if global identification would predict higher levels of gay-male identity integration, and indirectly subjective well-being, via alternative masculinity representations for gay and male identities. A community sample of 219 gay and bisexual men from Turkey completed the study. Structural equation modelling revealed that global identification positively predicted gay-male identity integration, and indirectly subjective well-being; however, alternative masculinity representations did not mediate this relationship. Our findings illustrate how identity categories in different domains can intersect and affect each other in complex ways. Moreover, we discuss mental health and well-being implications for gay men living in cultures where they experience high levels of prejudice and stigma. © 2016 The British Psychological Society.

The Impact of Gender on Anthropometric Measures of Twins.

PubMed

Jahanfar, Shayesteh; Lim, Kenneth

2016-12-01

Literature suggests that male hormones influence fetal growth in singleton pregnancies. We hypothesized that the same phenomenon is seen in twin gestations. (1) to identify the impact of gender associated with fetal birth weight, head circumference, and birth length for twins; (2) to examine the effect of gender on standardized fetal growth at birth, according to gestational age and birth order; (3) to examine the effect of gender on placenta weight and dimensions. This was a population-based retrospective cohort study of twins (4,368 twins, 2,184 pairs) born in British Columbia, Canada from 2000-2010. We excluded twins with stillbirth, congenital anomalies, and those delivered with cesarean section. We also controlled for confounding factors, including birth order, gestational age, maternal anthropometric measures, maternal smoking habits, and obstetric history. A subsample of this population was analyzed from Children and Women Hospital to obtain chorionicity information. Male-male twins were heavier than male-females and female-female twin pairs (p=.01). Within sex-discordant twin pairs, males were also heavier than females (p=.01). Regression analysis suggested that gender affects birth weight independent of birth order and gestational age. Other newborn anthropometric measures were not found to be dependent on gender. In analyzing a subsample with chorionicity data, birth weight was the only anthropometric measure that was both statistically and clinically affected by sex, even after adjustment for gestational age, chorionicity, birth order, and maternal age. Birth weight was affected by gender while head circumference and birth length were not.

Varieties of male-sexual-identity development in clinical practice: a neuropsychoanalytic model

PubMed Central

Stortelder, Frans

2014-01-01

Variations of sexual identity development are present in all cultures, as well as in many animal species. Freud – founding father of psychoanalysis – believed that all men have an inherited, bisexual disposition, and that many varieties of love and desire are experienced as alternative pathways to intimacy. In the neuropsychoanalytic model, psychic development starts with the constitutional self. The constitutional self is comprised of the neurobiological factors which contribute to sexual identity development. These neurobiological factors are focused on biphasic sexual organization in the prenatal phase, based on variations in genes, sex hormones, and brain circuits. This psychosocial construction of sexual identity is determined through contingent mirroring by the parents and peers of the constitutional self. The development of the self—or personal identity—is linked with the development of sexual identity, gender-role identity, and procreative identity. Incongruent mirroring of the constitutional self causes alienation in the development of the self. Such alienation can be treated within the psychoanalytic relationship. This article presents a contemporary, neuropsychoanalytic, developmental theory of male-sexual identity relating to varieties in male-sexual-identity development, with implications for psychoanalytic treatment, and is illustrated with three vignettes from clinical practice. PMID:25566168

Sex differences in the fetal heart rate variability indices of twins.

PubMed

Tendais, Iva; Figueiredo, Bárbara; Gonçalves, Hernâni; Bernardes, João; Ayres-de-Campos, Diogo; Montenegro, Nuno

2015-03-01

To evaluate the differences in linear and complex heart rate dynamics in twin pairs according to fetal sex combination [male-female (MF), male-male (MM), and female-female (FF)]. Fourteen twin pairs (6 MF, 3 MM, and 5 FF) were monitored between 31 and 36.4 weeks of gestation. Twenty-six fetal heart rate (FHR) recordings of both twins were simultaneously acquired and analyzed with a system for computerized analysis of cardiotocograms. Linear and nonlinear FHR indices were calculated. Overall, MM twins presented higher intrapair average in linear indices than the other pairs, whereas FF twins showed higher sympathetic-vagal balance. MF twins exhibited higher intrapair average in entropy indices and MM twins presented lower entropy values than FF twins considering the (automatically selected) threshold rLu. MM twin pairs showed higher intrapair differences in linear heart rate indices than MF and FF twins, whereas FF twins exhibited lower intrapair differences in entropy indices. The results of this exploratory study suggest that twins have sex-specific differences in linear and nonlinear indices of FHR. MM twins expressed signs of a more active autonomic nervous system and MF twins showed the most active complexity control system. These results suggest that fetal sex combination should be taken into consideration when performing detailed evaluation of the FHR in twins.

Education in Twins and Their Parents Across Birth Cohorts Over 100 years: An Individual-Level Pooled Analysis of 42-Twin Cohorts.

PubMed

Silventoinen, Karri; Jelenkovic, Aline; Latvala, Antti; Sund, Reijo; Yokoyama, Yoshie; Ullemar, Vilhelmina; Almqvist, Catarina; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth J F; Kandler, Christian; Honda, Chika; Inui, Fujio; Iwatani, Yoshinori; Watanabe, Mikio; Rebato, Esther; Stazi, Maria A; Fagnani, Corrado; Brescianini, Sonia; Hur, Yoon-Mi; Jeong, Hoe-Uk; Cutler, Tessa L; Hopper, John L; Busjahn, Andreas; Saudino, Kimberly J; Ji, Fuling; Ning, Feng; Pang, Zengchang; Rose, Richard J; Koskenvuo, Markku; Heikkilä, Kauko; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Sung, Joohon; Kim, Jina; Lee, Jooyeon; Lee, Sooji; Nelson, Tracy L; Whitfield, Keith E; Tan, Qihua; Zhang, Dongfeng; Llewellyn, Clare H; Fisher, Abigail; Burt, S Alexandra; Klump, Kelly L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Medland, Sarah E; Martin, Nicholas G; Montgomery, Grant W; Magnusson, Patrik K E; Pedersen, Nancy L; Dahl Aslan, Anna K; Corley, Robin P; Huibregtse, Brooke M; Öncel, Sevgi Y; Aliev, Fazil; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Catharina E M; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas S; Rasmussen, Finn; Tynelius, Per; Baker, Laura A; Tuvblad, Catherine; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Gatz, Margaret; Butler, David A; Lichtenstein, Paul; Goldberg, Jack H; Harden, K Paige; Tucker-Drob, Elliot M; Duncan, Glen E; Buchwald, Dedra; Tarnoki, Adam D; Tarnoki, David L; Franz, Carol E; Kremen, William S; Lyons, Michael J; Maia, José A; Freitas, Duarte L; Turkheimer, Eric; Sørensen, Thorkild I A; Boomsma, Dorret I; Kaprio, Jaakko

2017-10-01

Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.

Institutional Identity and Self-Esteem among African American Males in College

ERIC Educational Resources Information Center

Thomas, Dominique L.; Smith, Chauncey D.; Marks, Bryant T.; Crosby, Brandon

2012-01-01

Social identity theory maintains that one's self-concept is partially determined by the social groups to which the individual belongs. Using this as a theoretical framework, this study examined the relationship between multiple dimensions of institutional identity and self-esteem in 411 Black male college freshmen. It was hypothesized that…

Racial and gender identity among Black adolescent males: an intersectionality perspective.

PubMed

Rogers, Leoandra Onnie; Scott, Marc A; Way, Niobe

2015-01-01

A considerable amount of social identity research has focused on race and racial identity, while gender identity, particularly among Black adolescents, remains underexamined. The current study used survey data from 183 Black adolescent males (13-16 years old) to investigate the development and relation between racial and gender identity centrality and private regard, and how these identities impact adjustment over time. It was found that dimensions of racial and gender identity were strongly correlated. Levels of racial centrality increased over time while gender centrality, and racial and gender private regard declined. In addition, racial and gender identity uniquely contributed to higher levels of psychological well-being and academic adjustment. These findings are discussed within the context of existing identity theories and intersectionality theory. © 2014 The Authors. Child Development © 2014 Society for Research in Child Development, Inc.

Kelly during Twins Study Experiment Operations

NASA Image and Video Library

2015-09-24

ISS045E028258 (09/24/2015) --- NASA astronaut Scott Kelly gives himself a flu shot for an ongoing study on the human immune system. The vaccination is part of NASA’s Twins Study, a compilation of multiple investigations that take advantage of a unique opportunity to study identical twin astronauts Scott and Mark Kelly, while Scott spends a year aboard the International Space Station and Mark remains on Earth.

Twin and Triplet Drugs in Opioid Research

NASA Astrophysics Data System (ADS)

Fujii, Hideaki

Twin and triplet drugs are defined as compounds that contain respectively two and three pharmacophore components exerting pharmacological effects in a molecule. The twin drug bearing the same pharmacophores is a "symmetrical twin drug", whereas that possessing different pharmacophores is a "nonsymmetrical twin drug." In general, the symmetrical twin drug is expected to produce more potent and/or selective pharmacological effects, whereas the nonsymmetrical twin drug is anticipated to show both pharmacological activities stemming from the individual pharmacophores (dual action). On the other hand, nonsymmetrical triplet drugs, which have two of the same pharmacophores and one different moiety, are expected to elicit both increased pharmacological action and dual action. The two identical portions could bind the same receptor sites simultaneously while the third portion could bind a different receptor site or enzyme. This review will mainly focus on the twin and triplet drugs with an evaluation of their in vivo pharmacological effects, and will also include a description of their pharmacology and synthesis.

The Spread of Substance Use and Delinquency between Adolescent Twins

ERIC Educational Resources Information Center

Laursen, Brett; Hartl, Amy C.; Vitaro, Frank; Brendgen, Mara; Dionne, Ginette; Boivin, Michel

2017-01-01

This investigation examines the spread of problem behaviors (substance use and delinquency) between twin siblings. A sample of 628 twins (151 male twin pairs and 163 female twin pairs) drawn from the Quebec Newborn Twin Study completed inventories describing delinquency and substance use at ages 13, 14, and 15. A 3-wave longitudinal actor-partner…

Education in Time: Cohort Differences in Educational Attainment in African-American Twins

PubMed Central

Szanton, Sarah L.; Johnson, Brandon; Thorpe, Roland J.; Whitfield, Keith

2009-01-01

Objectives Educational opportunities for African-Americans expanded throughout the 20th century. Twin pairs are an informative population in which to examine changes in educational attainment because each twin has the same parents and childhood socioeconomic status. We hypothesized that correlation in educational attainment of older twin pairs would be higher compared to younger twin pairs reflecting changes in educational access over time and potentially reflecting a “ceiling effect” associated with Jim Crow laws and discrimination. Methodology and Principal Findings We used data from 211 same-sex twin pairs (98 identical, 113 fraternal) in the Carolina African-American Twin Study of Aging who were identified through birth records. Participants completed an in-person interview. The twins were predominantly female (61%), with a mean age of 50 years (SD = 0.5). We found that older age groups had a stronger intra-twin correlation of attained educational level. Further analysis across strata revealed a trend across zygosity, with identical twins demonstrating more similar educational attainment levels than did their fraternal twin counterparts, suggesting a genetic influence. Discussion These findings suggest that as educational opportunities broadened in the 20th century, African-Americans gained access to educational opportunities that better matched their individual abilities. PMID:19888338

Patterns of Racial Identity Development of African American Adolescent Males and Females.

ERIC Educational Resources Information Center

Plummer, Deborah L.

1995-01-01

Examined patterns of racial identity expression for 174 black adolescent females and 111 black adolescent males. Results from the Black Racial Identity Attitude Scale reveal that black adolescents widely endorse internalization attitudes that represent a healthy, self-defined racial transcendence. Females endorsed less preencounter attitudes…

Adult-onset acral peeling skin syndrome in a non-identical twin: a case report in South Africa.

PubMed

Mathew, Reshmi; Omole, Olufemi B; Rigby, Jonathan; Grayson, Wayne

2014-12-31

Acral peeling skin syndrome is a rare autosomal recessive disorder in which skin exfoliation is limited to the hands and feet. While it typically manifests from early childhood, in this first reported case from South Africa, the patient did not manifest clinically until the fourth decade of life. A 44-year-old woman of African descent, 1 of a set of non-identical twins, presented with recurrent episodes of skin peeling of the upper and lower limbs. The first episode occurred 4 years prior, followed by perennial skin peeling during the spring seasons. She was not on treatment for any chronic disease and reported no exposure to chemicals or other irritants. The family, including the non-identical twin sister, has no history of skin disorders and the patient's HIV antibody test was negative. At presentation, physical examination revealed ongoing exfoliation with new skin formation on the palms and soles. The mucous membranes and nails were spared. Other systems were normal. Skin biopsy taken from the palms confirmed peeling skin syndrome. The patient was managed with topical aqueous cream and analgesics. She was briefly counseled on the nature and prognosis of the disease, and referred for genetic testing and counseling. On follow-up, she continues to have skin peeling once or twice a year. This first reported case of this rare disease in South Africa contributes to the growing body of literature on the disease and highlights the need for clinicians to be aware of its variable clinical onset.

Twin methodology in epigenetic studies.

PubMed

Tan, Qihua; Christiansen, Lene; von Bornemann Hjelmborg, Jacob; Christensen, Kaare

2015-01-01

Since the final decades of the last century, twin studies have made a remarkable contribution to the genetics of human complex traits and diseases. With the recent rapid development in modern biotechnology of high-throughput genetic and genomic analyses, twin modelling is expanding from analysis of diseases to molecular phenotypes in functional genomics especially in epigenetics, a thriving field of research that concerns the environmental regulation of gene expression through DNA methylation, histone modification, microRNA and long non-coding RNA expression, etc. The application of the twin method to molecular phenotypes offers new opportunities to study the genetic (nature) and environmental (nurture) contributions to epigenetic regulation of gene activity during developmental, ageing and disease processes. Besides the classical twin model, the case co-twin design using identical twins discordant for a trait or disease is becoming a popular and powerful design for epigenome-wide association study in linking environmental exposure to differential epigenetic regulation and to disease status while controlling for individual genetic make-up. It can be expected that novel uses of twin methods in epigenetic studies are going to help with efficiently unravelling the genetic and environmental basis of epigenomics in human complex diseases. © 2015. Published by The Company of Biologists Ltd.

Does the sex of one's co-twin affect height and BMI in adulthood? A study of dizygotic adult twins from 31 cohorts.

PubMed

Bogl, Leonie H; Jelenkovic, Aline; Vuoksimaa, Eero; Ahrenfeldt, Linda; Pietiläinen, Kirsi H; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Hur, Yoon-Mi; Jeong, Hoe-Uk; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Cutler, Tessa L; Kandler, Christian; Jang, Kerry L; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; Derom, Catherine A; Vlietinck, Robert F; Nelson, Tracy L; Whitfield, Keith E; Corley, Robin P; Huibregtse, Brooke M; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos C E M; Pang, Zengchang; Tan, Qihua; Zhang, Dongfeng; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Hjelmborg, Jacob V B; Rebato, Esther; Swan, Gary E; Krasnow, Ruth; Busjahn, Andreas; Lichtenstein, Paul; Öncel, Sevgi Y; Aliev, Fazil; Baker, Laura A; Tuvblad, Catherine; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Duncan, Glen E; Buchwald, Dedra; Tarnoki, Adam D; Tarnoki, David L; Yokoyama, Yoshie; Hopper, John L; Loos, Ruth J F; Boomsma, Dorret I; Sørensen, Thorkild I A; Silventoinen, Karri; Kaprio, Jaakko

2017-01-01

The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI), and the prevalence of being overweight or obese between men and women from OS and SS dizygotic twin pairs. The data were derived from the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) database, and included 68,494 SS and 53,808 OS dizygotic twin individuals above the age of 20 years from 31 twin cohorts representing 19 countries. Zygosity was determined by questionnaires or DNA genotyping depending on the study. Multiple regression and logistic regression models adjusted for cohort, age, and birth year with the twin type as a predictor were carried out to compare height and BMI in twins from OS pairs with those from SS pairs and to calculate the adjusted odds ratios and 95% confidence intervals for being overweight or obese. OS females were, on average, 0.31 cm (95% confidence interval (CI) 0.20, 0.41) taller than SS females. OS males were also, on average, taller than SS males, but this difference was only 0.14 cm (95% CI 0.02, 0.27). Mean BMI and the prevalence of overweight or obesity did not differ between males and females from SS and OS twin pairs. The statistically significant differences between OS and SS twins for height were small and appeared to reflect our large sample size rather than meaningful differences of public health relevance. We found no evidence to support the hypothesis that prenatal hormonal exposure or postnatal socialization (i.e., having grown up with a twin of the opposite sex) has a major impact on height and BMI in adulthood.

Spinocerebellar ataxia in monozygotic twins.

PubMed

Anderson, John H; Christova, Peka S; Xie, Ting-dong; Schott, Kelly S; Ward, Kenneth; Gomez, Christopher M

2002-12-01

Although phenotypic heterogeneity in autosomal dominant spinocerebellar ataxia (SCA) has been explained in part by genotypic heterogeneity, clinical observations suggest the influence of additional factors. To demonstrate, quantitate, and localize physiologic abnormalities attributable to nongenetic factors in the development of hereditary SCA. Quantitative assessments of ocular motor function and postural control in 2 sets of identical twins, one with SCA type 2 and the other with episodic ataxia type 2. University laboratory. Saccadic velocity and amplitude, pursuit gain, and dynamic posturography. We found significant differences in saccade velocity, saccade metrics, and postural stability between each monozygotic twin. The differences point to differential involvement between twins of discrete regions in the cerebellum and brainstem. These results demonstrate the presence of quantitative differences in the severity, rate of progression, and regional central nervous system involvement in monozygotic twins with SCA that must be owing to the existence of nongermline or external factors.

Discordant Umbilical Cord Drug Testing Results in Monozygotic Twins.

PubMed

Alexander, Amy; Abbas, Liaqat; Jones, Mary; Jones, Joseph; Lewis, Douglas; Negrusz, Adam

2018-06-01

Our laboratory received segments of umbilical cord that originated from identical twins for routine toxicology analysis. The specimens were analyzed multiple times by liquid chromatography tandem mass spectrometry. The umbilical cord from newborn #1 was positive for hydromorphone only (1.06 ng/g), and the umbilical cord from newborn #2 was positive for hydromorphone (0.81 ng/g) and benzoylecgonine (5.41 ng/g). The hydromorphone results are consistent with maternal administration of hydromorphone; however, the cause of the discrepant benzoylecgonine results in the umbilical cords from the identical twins is unknown.

Genetic influences on musical specialization: a twin study on choice of instrument and music genre.

PubMed

Mosing, Miriam A; Ullén, Fredrik

2018-05-09

Though several studies show that genetic factors influence individual differences in musical engagement, aptitude, and achievement, no study to date has investigated whether specialization among musically active individuals in terms of choice of instrument and genre is heritable. Using a large twin cohort, we explored whether individual differences in instrument choice, instrument category, and the type of music individuals engage in can entirely be explained by the environment or are partly due to genetic influences. About 10,000 Swedish twins answered an extensive questionnaire about music-related traits, including information on the instrument and genre they played. Of those, 1259 same-sex twin pairs reported to either play an instrument or sing. We calculated the odds ratios (ORs) for concordance in music choices (if both twins played) comparing identical and nonidentical twin pairs, with significant ORs indicating that identical twins are more likely to engage in the same type of music-related behavior than are nonidentical twins. The results showed that for almost all music-related variables, the odds were significantly higher for identical twins to play the same musical instrument or music genre, suggesting significant genetic influences on such music specialization. Possible interpretations and implications of the findings are discussed. © 2018 New York Academy of Sciences.

Black Adolescent Males: Intersections Among Their Gender Role Identity and Racial Identity and Associations With Self-Concept (Global and School).

PubMed

Buckley, Tamara R

2017-09-12

Intersectional approaches for understanding identity have gained momentum in the social sciences. Black adolescent males are often perceived as threatening, underachieving, and hypermasculine, which is reinforced through media outlets and psychological research that portray them as a monolith rather than a heterogeneous group with multiple intersecting identities. This cross-sectional study of 70 Black adolescent males between 14 and 18 years old simultaneously explores their race and gender identities and associations with self-concept (global and school). Results demonstrated that participants reported a combination of feminine and masculine gender roles, rather than hypermasculine. A canonical correlation analysis found that Black racial identity attitudes (RIAS-L) and gender roles simultaneously contributed to significant relationships with total and school self-concept. Study limitations and future directions for research and practice are discussed. © 2017 The Authors. Child Development © 2017 Society for Research in Child Development, Inc.

Superheroes v Demons: Constructing Identities of Male Student Teachers in the Early Years

ERIC Educational Resources Information Center

Jones, Deborah

2008-01-01

This article presents research undertaken among male teachers and it explores their perceptions and experiences of working in early years contexts. It examines prevalent, contrary discourses and their impact on the construction of male teachers' identities. Public discourses in relation to male teachers reveal contradictions and ambiguities…

Masculinity unraveled: the roots of male gender identity and the shifting of male ego ideals throughout life.

PubMed

Diamond, Michael J

2006-01-01

A model of masculine gender identity development is presented that demonstrates how a male's sense of his masculinity and the ambiguities of his gender are being reworked throughout his life. Of factors shaping the boy's sense of masculinity early on, particular emphasis is placed on the role of the involved father, the nature of the parental relationship, and the mother's recognition and affirmation of her son's maleness. While healthy masculine gender identity is founded predominantly on the boy's unique struggles in separating from his mother, it does not result from what has been traditionally viewed as the boy's disidentification from her (and from the feminine more generally). Indeed, boys who need to violently repudiate their identifications with their mother are more susceptible to a fragile, rigid masculine identity and narcissistic psychopathology. A case example of a young adult man illustrates the impact of identifications with both parents. The interplay of early masculine identity development and later life challenges confronting the adult male is briefly noted. "Masculine" ego ideals shift across developmental junctions until, ultimately, a more mature sense of masculinity emerges: the phallic wish to deny differentiation and maintain unlimited possibility is renounced and mourned and certain real limits concerning sex, gender, and generational differences are accepted. This reshaping of the "masculine" ego ideal consequently involves the transformation of a man's previously adaptive "phallicism" into more realistic, "genital" ego ideals-an achievement involving interplay between masculine and feminine identifications and the integration of antithetical elements no longer so unconsciously gendered.

Differences in personality traits between male-to-female and female-to-male gender identity disorder subjects.

PubMed

Miyajima, Eiichi; Taira, Naoki; Koda, Munenaga; Kondo, Tsuyoshi

2014-12-15

The present study aimed to investigate differences in personality traits among male-to-female (MtF), female-to-male (FtM) gender identity disorder (GID) subjects and non-transsexual male (M) and female (F) controls. Subjects were 72 MtF and 187 FtM GID subjects without psychiatric comorbidities together with 184 male and 159 female non-transsexual controls. Personality traits were assessed using a short version of the Temperament and Character Inventory (TCI-125). Group comparisons were made by two-way ANOVA. Statistical significances were observed as follows: 1) lower novelty seeking in FtM than in M or MtF, 2) higher reward dependence in FtM than in M, 3) higher cooperativeness in FtM than in M or MtF, 4) the highest self-transcendence in MtF among all the groups. The highest self-transcendence in MtF subjects may reflect their vulnerable identity and constrained adaptation to society as the minority. Nevertheless, higher reward dependence and cooperativeness in FtM subjects can be related to more determined motivation for the treatments of GID and might promise better social functioning and adjustment than MtF subjects. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Anorexia nervosa and gender identity disorder in biologic males: a report of two cases.

PubMed

Winston, Anthony P; Acharya, Sudha; Chaudhuri, Shreemantee; Fellowes, Lynette

2004-07-01

Gender identity disorder is a rare disorder of uncertain etiology. The emphasis on body shape in this disorder suggests that there may be an association with anorexia nervosa. We report two cases of anorexia nervosa and gender identity disorder in biologic males who presented to an eating disorders service. One was treated successfully as an outpatient and subsequently underwent gender reassignment surgery. The other patient required admission and prolonged psychotherapy. Differences between the two cases are discussed. Issues of gender identity should be considered in the assessment of male patients presenting with anorexia nervosa. Copyright 2004 by Wiley Periodicals, Inc.

Attitudes towards human reproductive cloning, assisted reproduction and gene selection: a survey of 4600 British twins.

PubMed

Prainsack, B; Cherkas, L F; Spector, T D

2007-08-01

Surveys have shown opposition to human reproductive cloning (HRC) in many countries. Views of identical (monozygotic, MZ) twins are of particular interest, as they naturally share 100% of their genes. We investigated attitudes of British twins towards HRC in the context of assisted reproduction technologies (ART) and gene selection. About 4651 identical and non-identical (dizygotic, DZ) twins expressed their degree of agreement or disagreement to nine statements relating to ART, gene selection and HRC in a self-completion questionnaire. Most subjects (70% and 78% respectively) did not regard the use of medical technologies to treat infertility as interfering with either nature or God's will, despite believing that infertility is not a disease (54%). Attitudes to gene selection and HRC were context dependent, with more favourable views towards preventing serious diseases than towards enhancing traits. About 44% supported a permanent ban of HRC. MZ twins were significantly more likely to agree that HRC should be allowed for medical purposes, such as saving a sibling's life, than were DZ twins. Increasing religiosity generally correlated with more negative attitudes. Many attitudes are context dependent. More positive views of MZ twins towards HRC could be linked to their experience with being genetically identical.

Adult-Onset Acral Peeling Skin Syndrome in a Non-Identical Twin: A Case Report in South Africa

PubMed Central

Mathew, Reshmi; Omole, Olufemi B.; Rigby, Jonathan; Grayson, Wayne

2014-01-01

Patient: Female, 44 Final Diagnosis: Acral peeeling skin syndrome Symptoms: Recurrent skin exfoliation Medication: — Clinical Procedure: Skin biopsy Specialty: Dermatology Objective: Rare disease Background: Acral peeling skin syndrome is a rare autosomal recessive disorder in which skin exfoliation is limited to the hands and feet. While it typically manifests from early childhood, in this first reported case from South Africa, the patient did not manifest clinically until the fourth decade of life. Case Report: A 44-year-old woman of African descent, 1 of a set of non-identical twins, presented with recurrent episodes of skin peeling of the upper and lower limbs. The first episode occurred 4 years prior, followed by perennial skin peeling during the spring seasons. She was not on treatment for any chronic disease and reported no exposure to chemicals or other irritants. The family, including the non-identical twin sister, has no history of skin disorders and the patient’s HIV antibody test was negative. At presentation, physical examination revealed ongoing exfoliation with new skin formation on the palms and soles. The mucous membranes and nails were spared. Other systems were normal. Skin biopsy taken from the palms confirmed peeling skin syndrome. The patient was managed with topical aqueous cream and analgesics. She was briefly counseled on the nature and prognosis of the disease, and referred for genetic testing and counseling. On follow-up, she continues to have skin peeling once or twice a year. Conclusions: This first reported case of this rare disease in South Africa contributes to the growing body of literature on the disease and highlights the need for clinicians to be aware of its variable clinical onset. PMID:25549719

A Twin Protection Effect? Explaining Twin Survival Advantages with a Two-Process Mortality Model

PubMed Central

2016-01-01

Twin studies that focus on the correlation in age-at-death between twin pairs have yielded important insights into the heritability and role of genetic factors in determining lifespan, but less attention is paid to the biological and social role of zygosity itself in determining survival across the entire life course. Using data from the Danish Twin Registry and the Human Mortality Database, we show that monozygotic twins have greater cumulative survival proportions at nearly every age compared to dizygotic twins and the Danish general population. We examine this survival advantage by fitting these data with a two-process mortality model that partitions survivorship patterns into extrinsic and intrinsic mortality processes roughly corresponding to acute, environmental and chronic, biological origins. We find intrinsic processes confer a survival advantage at older ages for males, while at younger ages, all monozygotic twins show a health protection effect against extrinsic death akin to a marriage protection effect. While existing research suggests an increasingly important role for genetic factors at very advanced ages, we conclude that the social closeness of monozygotic twins is a plausible driver of the survival advantage at ages <65. PMID:27192433

Metabolism of sex steroids is influenced by acquired adiposity-A study of young adult male monozygotic twin pairs.

PubMed

Vihma, Veera; Naukkarinen, Jussi; Turpeinen, Ursula; Hämäläinen, Esa; Kaprio, Jaakko; Rissanen, Aila; Heinonen, Sini; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Mikkola, Tomi S; Tikkanen, Matti J; Pietiläinen, Kirsi H

2017-09-01

Obesity and ageing are associated with lower serum testosterone levels in men. How fat distribution or adipose tissue metabolism, independent of genetic factors and age, are related to sex steroid metabolism is less clear. We studied the associations between adiposity and serum sex hormone concentrations, and mRNA expression of genes regulating sex hormone metabolism in adipose tissue in young adult male monozygotic (MZ) twin pairs. The subjects [n=18 pairs; mean age, 32 years; individual body mass indexes (BMIs) 22-36kg/m 2 ] included 9 male MZ twin pairs discordant for BMI [intra-pair difference (Δ) in BMI ≥3kg/m 2 ]. Sex steroid concentrations were determined by liquid chromatography-tandem mass spectrometry, body composition by dual-energy X-ray absorptiometry and magnetic resonance imaging, and mRNA expressions from subcutaneous adipose tissue by Affymetrix. In BMI-discordant pairs (mean ΔBMI=5.9kg/m 2 ), serum dihydrotestosterone (DHT) was lower [mean 1.9 (SD 0.7) vs. 2.4 (1.0) nmol/l, P=0.040] and mRNA expressions of DHT-inactivating AKR1C2 (P=0.021) and cortisol-producing HSD11B1 (P=0.008) higher in the heavier compared to the leaner co-twins. Serum free 17β-estradiol (E2) was higher [2.3 (0.5) vs. 1.9 (0.5) pmol/l, P=0.028], and in all twin pairs, serum E2 and estrone concentrations were higher in the heavier than in the leaner co-twins [107 (28) vs. 90 (22) pmol/l, P=0.006; and 123 (43) vs. 105 (27) pmol/l, P=0.025]. Within all twin pairs, i.e. independent of genetic effects and age, 1) the amount of subcutaneous fat inversely correlated with serum total and free testosterone, DHT, and sex hormone-binding globulin (SHBG) concentrations (P<0.01 for all), 2) intra-abdominal fat with total testosterone and SHBG (P<0.05), and 3) liver fat with SHBG (P=0.006). Also, 4) general and intra-abdominal adiposity correlated positively with mRNA expressions of AKR1C2, HSD11B1, and aromatase in adipose tissue (P<0.05). In conclusion, acquired adiposity was

Family support and acceptance, gay male identity formation, and psychological adjustment: a path model.

PubMed

Elizur, Y; Ziv, M

2001-01-01

While heterosexist family undermining has been demonstrated to be a developmental risk factor in the life of persons with same-gender orientation, the issue of protective family factors is both controversial and relatively neglected. In this study of Israeli gay males (N = 114), we focused on the interrelations of family support, family acceptance and family knowledge of gay orientation, and gay male identity formation, and their effects on mental health and self-esteem. A path model was proposed based on the hypotheses that family support, family acceptance, family knowledge, and gay identity formation have an impact on psychological adjustment, and that family support has an effect on gay identity formation that is mediated by family acceptance. The assessment of gay identity formation was based on an established stage model that was streamlined for cross-cultural practice by defining three basic processes of same-gender identity formation: self-definition, self-acceptance, and disclosure (Elizur & Mintzer, 2001). The testing of our conceptual path model demonstrated an excellent fit with the data. An alternative model that hypothesized effects of gay male identity on family acceptance and family knowledge did not fit the data. Interpreting these results, we propose that the main effect of family support/acceptance on gay identity is related to the process of disclosure, and that both general family support and family acceptance of same-gender orientation play a significant role in the psychological adjustment of gay men.

Relationship of mode of conception and sex concordance with mortality/morbidity in preterm twins.

PubMed

Mirea, Lucia; Yang, Junmin; Paterson, Andrew D; Shah, Vibhuti; Bassil, Kate L; Lee, Shoo K; Shah, Prakesh S

2013-10-01

To assess the association of mode of conception and sex concordance with neonatal outcomes in very preterm twins. Twin pairs born at gestational age ≤ 32 weeks and admitted to a Level 3 neonatal intensive care unit (NICU) in 2010-2011 were retrospectively identified from the Canadian Neonatal Network™ database. A composite outcome representing neonatal mortality or any severe morbidity (intraventricular hemorrhage grades ≥ 3 or periventricular leukomalacia, retinopathy of prematurity stages ≥ 3, bronchopulmonary dysplasia, or necrotizing enterocolitis stages ≥ 2) was compared between twins conceived using assisted reproduction technologies (ARTs) or spontaneously (SP), and tested for association with sex concordance in individual-level and pair-wise multivariable logistic regression analyses. Study subjects included 1,508 twins from 216 ART (53 [25%] male-male, 104 [48%] male-female, and 59 [27%] female-female) and 538 SP (192 [36%] male-male, 123 [23%] male-female, and 223 [41%] female-female) pairs. No statistically significant association was detected between mode of conception and the composite outcome of mortality/morbidities. The composite outcome was significantly higher in same-sex than in opposite-sex twins (OR = 1.68; 95% CI = [1.09, 2.59]). This relationship was most pronounced in ART pairs (OR = 2.25; 95% CI = [1.02, 4.98]), with increased rates in one or both twins from male-male versus opposite-sex ART pairs (OR = 3.0; 95% CI = [1.07, 8.36]). Same-sex pairing was associated with higher mortality/morbidities in very preterm twins admitted to the NICU, and can be used in clinical practice to identify twins at higher risk of adverse neonatal outcomes.

Achieving Masculinity: A Review of the Literature on Male Gender Identity Development.

ERIC Educational Resources Information Center

Puls, Daniel W.

Distinctions between males and females arise as a result of a complex developmental process involving biological, psychological, and sociological forces. Much research on male gender identity development has spurred from the increased interest in the etiology of homosexuality over the last two decades. Political, religious, and moral issues often…

Twin-to-Twin Heart Transplantation: A Unique Event With a 25-Year Follow-Up.

PubMed

Blitzer, David; Yedlicka, Grace; Manghelli, Joshua; Dentel, John; Caldwell, Randall; Brown, John W

2017-04-01

Solid organ transplantation in pediatric patients has been a reality since 1954, when the first kidney transplantation was successfully performed between identical twins. We report the long-term outcomes, with more than 25 years of follow-up, in a patient born with hypoplastic left heart syndrome (HLHS) who received a heart transplant from a dizygotic twin. While we would not wish for this situation to reoccur, we hope that in reporting it, we can add to the discussion surrounding pediatric heart transplantation and the management of HLHS. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Twins and transsexualism: an update and a preview; research reviews: conjoined twins, angiographic lesions, single versus double embryo transfer; headlines: school placement legislation, Junior Taekwondo Olympics, prosthetic ears, murder victim.

PubMed

Segal, Nancy L

2007-12-01

In recent years, there has been growing appreciation for the complexity of gender identity. Focusing on monozygotic (MZ) twins discordant for transsexualism can offer clues to events that may trigger this behavioral difference, offering new information about critical underlying factors. An update of twin research in this area is provided, together with a preview of a compelling new film, 'Red Without Blue.' Next, twin study findings on the topics of conjoined twinning, angiographic lesions and embryo transfer are provided. This is followed by a survey of newsworthy twins and twin-related events.

Reflectance spectrometry of placental vessels in cases of twin-twin transfusion syndrome: experiments and modeling

NASA Astrophysics Data System (ADS)

Lines, Collin; Kim, Oleg; McMurdy, John; Luks, Francois; Alber, Mark; Crawford, Greg

2013-03-01

A stochastic photon transport model in multilayer skin tissue combined with reflectance spectroscopy measurements is used to study placental vessels in cases of twin-twin transfusion syndrome (TTTS). TTTS occurs in about 12% of monozygotic (identical) twin pregnancies wherein flow within placental vessels linking the twins together becomes unbalanced, leading to dual mortality. Endoscopic laser ablation can halt the syndrome by occluding the anastomoses connecting the two fetuses. The objective of this study is to develop a technique to determine hemoglobin (Hb) content through spectral analysis of diffuse reflectance spectra of placental vessels to aid in identification of the anastomoses. Previous work by researchers at Brown University has shown that the reflectance spectra of the donor twin and recipient twin are considerably different in the wavelengths for Hb absorbance. This presentation will give preliminary results for a Monte Carlo model adapted to fit the physiology of the placenta that can be used to quantitative determine the Hb levels. The reflectance spectra of the vessels are simulated for different values of Hb as well oxygenation and water concentration with the vessel and placental mass. The preliminary results will be shown to be in good approximation with the prior experimental data. The combination of modeling with spectroscopic measurement will provide a new tool for detailed prenatal study.

Differences in Religiousness in Opposite-Sex and Same-Sex Twins in a Secular Society.

PubMed

Ahrenfeldt, Linda J; Lindahl-Jacobsen, Rune; Möller, Sören; Christensen, Kaare; Hvidtjørn, Dorte; Hvidt, Niels Christian

2016-02-01

Sex differences in religion are well known, with females generally being more religious than males, and shared environmental factors have been suggested to have a large influence on religiousness. Twins from opposite-sex (OS) and same-sex (SS) pairs may differ because of a dissimilar psycho-social rearing environment and/or because of different exposures to hormones in utero. We hypothesized that OS females may display more masculine patterns of religiousness and, vice versa, that OS males may display more feminine patterns. We used a web-based survey conducted in Denmark, which is a secular society. The survey included 2,997 twins aged 20-40 years, identified through the population-based Danish Twin Registry. We applied la Cour and Hvidt's adaptation of Fishman's three conceptual dimensions of meaning: Cognition, Practice, and Importance, and we used Pargament's measure of religious coping (RCOPE) for the assessment of positive and negative religious coping patterns. Differences between OS and SS twins were investigated using logistic regression for each sex. The analyses were adjusted for dependence within twin pairs. No significant differences in religiousness and religious coping were found for OS and SS twins except that more OS than SS females were members of the Danish National Evangelical Lutheran Church and fewer OS than SS females were Catholic, Muslim, or belonged to other religious denominations. Moreover, OS males at age 12 had higher rates of church attendance than did SS males. This study did not provide evidence for masculinization of female twins with male co-twins with regard to religiousness. Nor did it show any significant differences between OS and SS males except from higher rates of church attendance in childhood among males with female co-twins.

Differences in Religiousness in Opposite-Sex and Same-Sex Twins in a Secular Society

PubMed Central

Ahrenfeldt, Linda J.; Lindahl-Jacobsen, Rune; Möller, Sören; Christensen, Kaare; Hvidtjørn, Dorte; Hvidt, Niels Christian

2016-01-01

Sex differences in religion are well known, with females generally being more religious than males, and shared environmental factors have been suggested to have a large influence on religiousness. Twins from opposite-sex (OS) and same-sex (SS) pairs may differ because of a dissimilar psycho-social rearing environment and/or because of different exposures to hormones in utero. We hypothesized that OS females may display more masculine patterns of religiousness and, vice versa, that OS males may display more feminine patterns. We used a web-based survey conducted in Denmark, which is a secular society. The survey included 2,997 twins aged 20–40 years, identified through the population-based Danish Twin Registry. We applied la Cour and Hvidt’s adaptation of Fishman’s three conceptual dimensions of meaning: Cognition, Practice, and Importance, and we used Pargament’s measure of religious coping (RCOPE) for the assessment of positive and negative religious coping patterns. Differences between OS and SS twins were investigated using logistic regression for each sex. The analyses were adjusted for dependence within twin pairs. No significant differences in religiousness and religious coping were found for OS and SS twins except that more OS than SS females were members of the Danish National Evangelical Lutheran Church and fewer OS than SS females were Catholic, Muslim, or belonged to other religious denominations. Moreover, OS males at age 12 had higher rates of church attendance than did SS males. This study did not provide evidence for masculinization of female twins with male co-twins with regard to religiousness. Nor did it show any significant differences between OS and SS males except from higher rates of church attendance in childhood among males with female co-twins. PMID:26689907

Listening to their voices: Exploring mathematics-science identity development of African American males in an urban school community

NASA Astrophysics Data System (ADS)

Wilson, Kimi Leemar

National data continues to show an underrepresentation of African American males pursuing science, technology, engineering and mathematics (STEM) majors, careers and professions in the United States. Whites and Asian Americans are continuously positioned as the face of STEM education and participation. And while research has provided ways to support mathematics and science learning for African American males, there still remains a gap in understanding how their formed mathematics-science identities in K-12 public schooling influences STEM participation. The research undertaken in this study explores this gap, and uses an integrative identity framework to understand mathematics-science identity development which goes beyond personal identity, and explores the relational, collective and material components of identity. Specifically, this research seeks to answer the following research questions: What are the shared lived experiences that exist between a group of African American male students developing a mathematics-science identity, and how these shared lived experiences shape their mathematics-science identity development? Therefore, by analyzing African American males lived experiences employing an integrative identity framework fosters a greater understanding of how mathematics-science identity is formed in K-12 public schools, which impacts STEM education and participation. The high school aged youth featured in this study consist of four African American males, who live in a moderate size city in California. Data for this study consists of observations, phenomenological interviews, and policy document analysis that took place over six months. Data has been analyzed to describe and interpret the young men's mathematics and science experiences, as revealed in their K-12 public school education. This inquiry sought to make meaning of how African American males experience mathematics and science teaching and learning within K-12 public schooling and how these

Nature, nurture and academic achievement: a twin study of teacher assessments of 7-year-olds.

PubMed

Walker, Sheila O; Petrill, Stephen A; Spinath, Frank M; Plomin, Robert

2004-09-01

Twin research has consistently shown substantial genetic influence on individual differences in cognitive ability; however, much less is known about the genetic and environmental aetiologies of school achievement. Our goal is to test the hypotheses that teacher-assessed achievement in the early school years shows substantial genetic influence but only modest shared environmental influence when children are assessed by the same teachers and by different teachers. 1,189 monozygotic (MZ) and dizygotic (DZ) twin pairs born in 1994 in England and Wales. Teachers evaluated academic achievement for 7-year-olds in Mathematics and English. Results were based on the twin method, which compares the similarity between identical and fraternal twins. Suggested substantial genetic influence in that identical twins were almost twice as similar as fraternal twins when compared on teacher assessments for Mathematics, English and a total score. The results confirm prior research suggesting that teacher assessments of academic achievement are substantially influenced by genetics. This finding holds even when twins are assessed independently by different teachers.

Paternal age and twinning in the Jerusalem Perinatal Study

PubMed Central

Kleinhaus, Karine; Perrin, Mary C.; Manor, O; Friedlander, Yehiel; Calderon-Margalit, Ronit; Harlap, Susan; Malaspina, Dolores

2008-01-01

Objective To investigate whether incidence of twin deliveries is related to father's age, independently of mother's age, and whether it differs for same-sex or opposite-sex twin sets. Study Design In a program of research on effects of paternal age, this study used data from a prospective cohort of 92,408 offspring born in Jerusalem from 1964-1976. Of the 91,253 deliveries in the Jerusalem Perinatal Study, 1,115 were twin deliveries. The data were analyzed with General Estimate Equations to inform unconditional logistic regression. Results After controlling for maternal age, Odds Ratios (OR) and 95% Confidence Intervals (95% CI) associated with father's ages 25-34 and 35+ were 1.3 (1.1, 1.7) and 1.5 (1.2, 2.1) respectively, compared with fathers <25 years old. The effect of maternal age was partly explained by paternal age. The ORs for opposite-sex twin sets and male-male twin sets increased slightly with paternal age, while the OR for same-sex and female-female twin decreased. Conclusion Studies of twins are used to estimate effects of genes and environment in a variety of diseases. Our findings highlight the need to consider paternal as well as maternal age when analyzing data on twins to explore etiology of diseases. PMID:18771839

Cohort Profile: The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry)

PubMed Central

Gatz, Margaret; Harris, Jennifer R; Kaprio, Jaakko; McGue, Matt; Smith, Nicholas L; Snieder, Harold; Spiro, Avron; Butler, David A

2015-01-01

The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry) is a comprehensive registry of White male twin pairs born in the USA between 1917 and 1927, both of the twins having served in the military. The purpose was medical research and ultimately improved clinical care. The cohort was assembled in the early 1960s with identification of approximately 16 000 twin pairs, review of service records, a brief mailed questionnaire assessing zygosity, and a health survey largely comparable to questionnaires used at that time with Scandinavian twin registries. Subsequent large-scale data collection occurred in 1974, 1985 and 1998, repeating the health survey and including information on education, employment history and earnings. Self-reported data have been supplemented with mortality, disability and medical data through record linkage. Potential collaborators should access the study website [http://www.iom.edu/Activities/Veterans/TwinsStudy.aspx] or e-mail the Medical Follow-up Agency at [Twins@nas.edu]. Questionnaire data are being prepared for future archiving with the National Archive of Computerized Data on Aging (NACDA) at the Inter-University Consortium for Political and Social Research (ICPSR), University of Michigan, MI. PMID:25183748

Asymmetries of the arcuate fasciculus in monozygotic twins: genetic and nongenetic influences.

PubMed

Häberling, Isabelle S; Badzakova-Trajkov, Gjurgjica; Corballis, Michael C

2013-01-01

We assessed cerebral asymmetry for language in 35 monozygotic twin pairs. Using DTI, we reconstructed the arcuate fasciculus in each twin. Among the male twins, right-handed pairs showed greater left-sided asymmetry of connectivity in the arcuate fasciculus than did those with discordant handedness, and within the discordant group the right-handers had greater left-sided volume asymmetry of the arcuate fasciculus than did their left-handed co-twins. There were no such effects in the female twins. Cerebral asymmetry for language showed more consistent results, with the more left-cerebrally dominant twins also showing more leftward asymmetry of high anisotropic fibers in the arcuate fasciculus, a result applying equally to female as to male twins. Reversals of arcuate fasciculus asymmetry were restricted to pairs discordant for language dominance, with the left-cerebrally dominant twins showing leftward and the right-cerebrally dominant twins rightward asymmetry of anisotropic diffusion in the arcuate fasciculus. Because monozygotic twin pairs share the same genotype, our results indicate a strong nongenetic component in arcuate fasciculus asymmetry, particularly in those discordant for cerebral asymmetry.

Cranio-dirachischisis totalis in cephalothoracopagus twins.

PubMed

Ferm, V H

1978-04-01

A set of conjoined 13-day-old male hamster twins is described. The twins were joined at the head and thorax. The brain was exencephalic and the neural plate was completely open throughout its length. The notochord was duplicated throughout its entire length. Partial twinning of the neural plate as indicated by histologic reconstruction is suggested with fusion or non-separation of the neural plates in the medial alar wing area. There was complete separation of the neural plates together with duplication of the lower extremities and tails in the caudal region of this specimen.

Mapping Me: Mapping Identity among Academically High-Performing Black Males

ERIC Educational Resources Information Center

Flennaugh, Terry K.

2016-01-01

Background: Scholars have argued that far too little research has examined the complex processes that many Black males undertake in constructing identities that function in schools (Howard & Flennaugh, 2011; Howard, Flennaugh, & Terry, 2012; Terry, Flennaugh, Blackmon, & Howard, 2014). Some have highlighted the perpetuation of a false…

Population-based birth weight reference percentiles for Chinese twins.

PubMed

Dai, Li; Deng, Changfei; Li, Yanhua; Yi, Ling; Li, Xiaohong; Mu, Yi; Li, Qi; Yao, Qiang; Wang, Yanping

2017-09-01

Birth weight percentiles by gestational age are important for assessing prenatal growth and predicting postnatal outcomes of newborns. Several countries have developed nation-specific birth weight references for twins, but China still lacks such references. Birth weight data for twins born between October 2006 and September 2015 were abstracted from the China National Population-based Birth Defects Surveillance System. A total of 54,786 live twin births aged ≥28 weeks of gestation without birth defects were included in the analysis. The LMS method was adopted to generate gestational age-specific birth weight percentiles and curves for male and female twins separately. Significant differences were observed between the current reference and other references developed for Chinese or non-Chinese twins. The neonatal mortality rate in this cohort was 12.3‰, and much higher rates at very early gestation weeks were identified in small-for-gestational-age twins grouped by the newly developed reference cutoffs. The established birth weight centiles represent the first birth weight norm for contemporary Chinese twins and can be a useful tool to assess growth of twins in clinical and research settings. Key Messages There have been no population-based birth weight percentiles for Chinese twins prior to this study. The established birth weight centiles for female and male twins are markedly lower than those for Chinese singletons. Twin-specific curves should be used for determining inappropriate for gestational age in twins rather than using existing singleton reference. The birth weight percentiles for twins differed significantly from those for non-Chinese twins. In addition to ethnic influences, the observed differences could be ascribed to variations in prenatal care, fetal or maternal nutrition status or other environmental factors. Neonatal mortality rates varied considerably among twins grouped by the newly developed reference percentiles. Small

Twin studies in psychiatry and psychology: science or pseudoscience?

PubMed

Joseph, Jay

2002-01-01

Twin studies are frequently cited in support of the influence of genetic factors for a wide range of psychiatric conditions and psychological trait differences. The most common method, known as the classical twin method, compares the concordance rates or correlations of reared-together identical (MZ) vs. reared-together same-sex fraternal (DZ) twins. However, drawing genetic inferences from MZ-DZ comparisons is problematic due to methodological problems and questionable assumptions. It is argued that the main theoretical assumption of the twin method--known as the "equal environment assumption"--is not tenable. The twin method is therefore of doubtful value as an indicator of genetic influences. Studies of reared-apart twins are discussed, and it is noted that these studies are also vulnerable to methodological problems and environmental confounds. It is concluded that there is little reason to believe that twin studies provide evidence in favor of genetic influences on psychiatric disorders and human behavioral differences.

Risk factors for testicular cancer: a case-control study in twins.

PubMed

Swerdlow, A J; De Stavola, B L; Swanwick, M A; Mangtani, P; Maconochie, N E

1999-06-01

Early life and anthropometric risk factors for testicular cancer were examined in a case-control study in England and Wales in which affected male twins were compared with their unaffected male co-twins. Questionnaire data was obtained for 60 twin pairs. Significantly raised risk of testicular cancer occurred in twins who had longer arms and legs than their co-twin. There was a significant excess of testicular cancer reported in non-twin brothers, as well as in twin brothers, of cases. Risk was also significantly raised in relation to cryptorchidism. The results on limb length suggest that factors, perhaps nutritional, affecting growth before puberty, may be causes of testicular cancer. The results on risk in brothers add to evidence of a large genetic component in aetiology of the tumour. The risk associated with cryptorchidism in the twins accords with the hypothesis that cryptorchidism is causally associated with testicular cancer because it is a cause of the malignancy, rather than because the same maternal factors experienced in utero cause both conditions.

Masculinity, male development, gender, and identity: modern and postmodern meanings.

PubMed

Phillips, Debby A

2006-05-01

Modern and postmodern scholars are addressing the crisis in masculinity by questioning the meaning of masculinity and by rethinking masculinity, male development, gender, and identity. This article explicates current modern humanist positions and postmodern positions on these topics. The first section summarizes contemporary theories advanced by scholars in the relatively new discipline of men's studies. The second section presents postmodern positions exploring sex as a biological given, the emerging critiques of differentiating sex and gender, and poststructural psychoanalytic positions on simultaneous production of individual subjectivity (sense of self), masculine identity, and society. Implications of these perspectives are identified.

Observing with Sibling and Twin Telescopes

NASA Astrophysics Data System (ADS)

Plank, Lucia; Lovell, Jim; McCallum, Jamie; Mayer, David

2016-12-01

With the transition to VGOS, co-located radio telescopes will be common at many sites. This can be as a sibling telescope when a VGOS antenna is built next to a legacy one, or as the concept of a twin telescope with two identical VGOS antennas. The co-location of two antennas offers new possibilities in both operation and analysis. The immediate question for observing with sibling/twin telescopes is the applied observing strategy and its realization in the scheduling software. In this contribution we report about our efforts implementing new scheduling modes for sibling and twin telescopes in the Vienna VLBI Software. For the example of the sibling telescope in Hobart, several types of sessions will be discussed: an improved tag-along mode for the 26-m antenna (Ho), a proper implementation of the twin-mode using the antenna with the shorter slewing time, and an astrometric support mode enabling the observation of weak sources with the AuScope array.

Cisgender male and transgender female sex workers in South Africa: gender variant identities and narratives of exclusion.

PubMed

Samudzi, Zoe; Mannell, Jenevieve

2016-01-01

Sex workers are often perceived as possessing 'deviant' identities, contributing to their exclusion from health services. The literature on sex worker identities in relation to health has focused primarily on cisgender female sex workers as the 'carriers of disease', obscuring the experiences of cisgender male and transgender sex workers and the complexities their gender identities bring to understandings of stigma and exclusion. To address this gap, this study draws on 21 interviews with cisgender male and transgender female sex workers receiving services from the Sex Workers Education and Advocacy Taskforce in Cape Town, South Africa. Our findings suggest that the social identities imposed upon sex workers contribute to their exclusion from public, private, discursive and geographic spaces. While many transgender female sex workers described their identities using positive and empowered language, cisgender male sex workers frequently expressed shame and internalised stigma related to identities, which could be described as 'less than masculine'. While many of those interviewed felt empowered by positive identities as transgender women, sex workers and sex worker-advocates, disempowerment and vulnerability were also linked to inappropriately masculinised and feminised identities. Understanding the links between gender identities and social exclusion is crucial to creating effective health interventions for both cisgender men and transgender women in sex work.

The Racial Identity Development of Male Student-Athletes when Blacks Are the Majority and Whites Are the Minority

ERIC Educational Resources Information Center

Henry, Wilma J.; Closson, Rosemary B.

2012-01-01

Focus groups were used in the present study to explore the racial identity development of Black male and White male student-athletes on a predominantly Black, Division IA football team at a predominantly White institution (PWI). Findings indicate that the Black male football players demonstrated positive indicators of Black racial identity. The…

Critical Influences on Sexual Minority College Males' Meaning-Making of Their Multiple Identities

ERIC Educational Resources Information Center

Tillapaugh, Daniel

2015-01-01

This grounded theory study explored the critical influences on college sexual minority males' meaning-making of their multiple identities. Twenty-six cisgender males attending colleges and universities within the United States and Canada were interviewed and provided journal responses to specific prompts. Four themes emerged, including:…

Male gender identity in children with 46,XX DSD with congenital adrenal hyperplasia after delayed presentation in mid-childhood.

PubMed

Chowdhury, Tanvir Kabir; Laila, Kamrun; Hutson, John M; Banu, Tahmina

2015-12-01

Girls with congenital adrenal hyperplasia (CAH) diagnosed at birth have some masculine behaviors but rarely convert to male gender. In developing countries, however, diagnosis and treatment (with secondary androgen suppression) are delayed. We aimed to assess effect of delayed treatment of CAH on gender identity. As part of a cross-sectional, case-control study of children with disorders of sex development (DSD), there were 11 patients with CAH. Patients and caregivers answered a questionnaire about gender identity, and behavior was assessed by observing toy play. Patients were examined for Prader score and gender identity. Of 11 CAH patients initially raised as girls, 3 (27%) had converted to male gender at presentation (5, 9, 9years) (Prader 3, 4, 4). Of the remaining 8 patients, one 4-year-old (Prader 2) had a male gender identity score. The remaining girls (2-13years, mean 8.1) (Prader 1-3) had gender identity scores in the female range. One third (4/11) of CAH patients presenting in mid-childhood had male gender identity scores, and ¾ had assumed male gender role. Although social and cultural factors are important in developing countries, this result suggests that delayed treatment may trigger male gender identity, and delayed female genital surgery may be unwise. Copyright © 2015 Elsevier Inc. All rights reserved.

Conjoined twins – role of imaging and recent advances

PubMed Central

Francis, Swati; Basti, Ram Shenoy; Suresh, Hadihally B.; Rajarathnam, Annie; Cunha, Prema D.; Rao, Sujaya V.

2017-01-01

Introduction Conjoined twins are identical twins with fused bodies, joined in utero. They are rare complications of monochorionic twinning. The purpose of this study is to describe the various types of conjoined twins, the role of imaging and recent advances aiding in their management. Material and methods This was a twin institutional study involving 3 cases of conjoined twins diagnosed over a period of 6 years from 2010 to 2015. All the 3 cases were identified antenatally by ultrasound. Only one case was further evaluated by MRI. Results Three cases of conjoined twins (cephalopagus, thoracopagus and omphalopagus) were accurately diagnosed on antenatal ultrasound. After detailed counseling of the parents and obtaining written consent, all the three cases of pregnancy were terminated. Delivery of the viable conjoined twins was achieved without any complications to the mothers, and all the three conjoined twins died after a few minutes. Conclusion Ultrasound enables an early and accurate diagnosis of conjoined twins, which is vital for obstetric management. MRI is reserved for better tissue characterization. Termination of pregnancy when opted, should be done at an early stage as later stages are fraught with problems. Recent advances, such as 3D printing, may aid in surgical pre-planning, thereby enabling successful surgical separation of conjoined twins. PMID:29375901

Thyroid aplasia in male sibling of heterozygotic twins born to the hyperthyroid mother treated with propylthiouracil during pregnancy (case report).

PubMed

Almarzouki, A A

2012-01-01

A 30-year-old pregnant female was diagnosed to have thyrotoxicosis (TSH= 0.005 µU/ml) at 13th week of gestation. Propylthiouracil (PTU; 200 mg daily) was prescribed to her and four weekly follow ups by the endocrinologist and obstetrician were ensured. At each examination TSH, FT4 and FT3 levels were normal and she became symptom free. Repeated ultrasound examination throughout the pregnancy did not reveal any fetal abnormality. The lady normally delivered heterozygotic twins. Umbilical cord blood of the baby boy twin showed a high TSH (541 µU/ml; reference range 0.270 - 4.20 μU/ml). He was started on thyroxine therapy (50 µg once daily). Ultrasound reported the absence of the thyroid gland. One month later TSH was within normal range and thyroxine dose was adjusted to 25 µg once daily. Repeated ultrasound confirmed the absence of thyroid gland. TSH was repeatedly normal. The boy is currently doing well on thyroxine replacement therapy. The other non-identical twin was a healthy girl with normal thyroid function tests and always thereafter. This case report suggested that PTU could be a hazardous drug to the fetus, since the mother gave birth to a baby with thyroid aplasia. PTU, Thyroid aplasia, Thyrotoxicosis, TSH.

Hirschsprung's disease in twins: a systematic review and meta-analysis.

PubMed

Henderson, D; Zimmer, J; Nakamura, H; Puri, Prem

2017-08-01

Hirschsprung's disease (HSCR) is known to occur in families. The reported overall incidence of familial cases is 7.6%, with a higher incidence of 15-21% in total colonic aganglionosis and 50% in the rare total intestinal aganglionosis. HSCR is extremely rare in twins. The aim of this study was to systematically analyse the patterns of HSCR in twins published in the literature. Electronic databases Pubmed and Medline were screened for relevant articles using the keywords "Hirschsprung's disease", "aganglionosis", "twins", "monozygotic", and "dizygotic". Examining reference lists identified further relevant papers. Twelve studies with a total of 18 twin pairs were included in this analysis. 67% twins were discordant. HSCR was found in 24 out of 36 twin subjects (67%), of which 83% affected were male. Rectosigmoid type was reported in 71% of patients, long-segment disease in 21, and 8% presented with a total aganglionosis. Three twin pairs had at least one family member affected with HSCR. HSCR was found in two-thirds of twin subjects with a male predominance. Rectosigmoid aganglionosis was the most common variant. Disease discordance was identified, where environmental insults were postulated to be predisposing factors to disease expression. Future studies investigating the disease-associated mutations in the already identified HSCR genes should provide insights into the genetic basis of HSCR in twins.

The relationship between help-seeking attitudes and masculine norms among monozygotic male twins discordant for sexual orientation.

PubMed

Sánchez, Francisco J; Bocklandt, Sven; Vilain, Eric

2013-01-01

In general, heterosexual men are less favorable to asking for help compared to women and gay men. This can be problematic if a man avoids professional help when he is experiencing significant psychological distress. Yet, it is unclear to what degree such attitudes among men are due to innate differences or social environments. Studying twins provides one avenue for teasing apart these relationships. We recruited 38 pairs of monozygotic male twins (Mage = 35.87 years, SD = 9.52) raised together and who were discordant for sexual orientation. They completed measures of psychological distress (Symptom Checklist-90-Revised), positive attitudes toward psychological help-seeking behavior, and emphasis with fulfilling traditional masculine norms. Contrary to predictions, the heterosexual twins expressed more symptoms of specific distress-hostility (r = .30), paranoid ideation (r = .26), and psychoticism (r = .24)-than their gay cotwins. As predicted, heterosexual men were less favorable to seeking help (r = .25) and expressed greater emphasis on masculine norms (r = .26) than their cotwins. Within each group of men, unique aspects of masculine norms were significantly related to attitudes toward psychological help-seeking behavior. The findings lend credence to the hypothesis that social environments influence attitudes and behaviors that are stereotypically masculine and potentially detrimental to men's health. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Mental Representations of Attachment in Identical Female Twins with and without Conduct Problems

ERIC Educational Resources Information Center

Constantino, John N.; Chackes, Laura M.; Wartner, Ulrike G.; Gross, Maggie; Brophy, Susan L.; Vitale, Josie; Heath, Andrew C.

2006-01-01

Insecure mental representations of attachment, a nearly invariant feature of cluster B personality disorders, have never previously been studied in twins. We conducted the Adult Attachment Interview (AAI) on 33 pairs of monozygotic (MZ) female twins reared together as an initial exploration of causal influences on mental representations of…

Physical activity, fitness, glucose homeostasis, and brain morphology in twins.

PubMed

Rottensteiner, Mirva; Leskinen, Tuija; Niskanen, Eini; Aaltonen, Sari; Mutikainen, Sara; Wikgren, Jan; Heikkilä, Kauko; Kovanen, Vuokko; Kainulainen, Heikki; Kaprio, Jaakko; Tarkka, Ina M; Kujala, Urho M

2015-03-01

The main aim of the present study (FITFATTWIN) was to investigate how physical activity level is associated with body composition, glucose homeostasis, and brain morphology in young adult male monozygotic twin pairs discordant for physical activity. From a population-based twin cohort, we systematically selected 10 young adult male monozygotic twin pairs (age range, 32-36 yr) discordant for leisure time physical activity during the past 3 yr. On the basis of interviews, we calculated a mean sum index for leisure time and commuting activity during the past 3 yr (3-yr LTMET index expressed as MET-hours per day). We conducted extensive measurements on body composition (including fat percentage measured by dual-energy x-ray absorptiometry), glucose homeostasis including homeostatic model assessment index and insulin sensitivity index (Matsuda index, calculated from glucose and insulin values from an oral glucose tolerance test), and whole brain magnetic resonance imaging for regional volumetric analyses. According to pairwise analysis, the active twins had lower body fat percentage (P = 0.029) and homeostatic model assessment index (P = 0.031) and higher Matsuda index (P = 0.021) compared with their inactive co-twins. Striatal and prefrontal cortex (subgyral and inferior frontal gyrus) brain gray matter volumes were larger in the nondominant hemisphere in active twins compared with those in inactive co-twins, with a statistical threshold of P < 0.001. Among healthy adult male twins in their mid-30s, a greater level of physical activity is associated with improved glucose homeostasis and modulation of striatum and prefrontal cortex gray matter volume, independent of genetic background. The findings may contribute to later reduced risk of type 2 diabetes and mobility limitations.

Leadership Effectiveness and Instructional Supervision: The Case of the Failing Twin

ERIC Educational Resources Information Center

Bloom, Collette Madeleine

2011-01-01

This case study examines the leadership practices of an effective versus an ineffective elementary school principal. The background of this case involves two fourth grade teachers, each teaching one of a set of identical twins. Discrepancies in teaching and grading practices result in one twin failing. The decision-making choices of the principal…

Oliver Sacks: Our Correspondence About Twins/Twin Research: Vanishing Twins Syndrome; Discordant Sex in MZ Twins; Pregnancy Outcomes in IVF and ICSI Conceived Twins/Print and Media: Superfetated Twins; Twins Discordant for Smoking; Twins in Fashion; Yale University Twin Hockey Players; Conjoined Twin-Visiting Professor.

PubMed

Segal, Nancy L

2017-08-01

The late neurologist and author, Oliver Sacks, published an insightful 1986 review of Marjorie Wallace's book, The Silent Twins, in the New York Times. Taking exception to his assertion about Sir Francis Galton, I wrote a letter to the Times' editor. The letter was unpublished, but it brought a wonderful response from Sacks himself that is reproduced and examined. Next, brief reviews of twin research concerning the vanishing twin syndrome (VTS), discordant sex in a monozygotic (MZ) twin pair, and multiple pregnancy outcomes from assisted reproductive technology (ART) are presented. This section is followed by popular coverage of superfetated twins, smoking-discordant co-twins, twins in fashion, Yale University twin hockey players, and a visiting professor who was a conjoined twin.

Racial-Ethnic Identity, Academic Achievement, and African American Males: A Review of Literature

ERIC Educational Resources Information Center

Wright, Brian L.

2009-01-01

This article discusses broadly, the literature on racial-ethnic identity (REI) and its role as a factor to promote academic success in young African American adolescents, in particular males. The review also defines, describes, and interprets styles of self-presentation that reflect aspects of REI among African American males in and outside of…

Genetic contribution to the relationship between social role function and depressive symptoms in Japanese elderly twins: a twin study.

PubMed

Nishihara, Reiko; Inui, Fujio; Kato, Kenji; Tomizawa, Rie; Hayakawa, Kazuo

2011-03-01

Social role function is the capacity to maintain interpersonal relationships and is essential for being independent in the community. Limitations in social role function often coexist with depressive symptoms, suggesting a possible common mechanistic basis. We investigated whether the observed association between these traits is mainly a result of genetic or environmental influences. In 2008, a questionnaire was sent to 745 male twins aged 65 years and older. Our sample included 397 male twins. The number of monozygotic twins was 302, and dizygotic was 95. Among the twin pairs for whom data were available for both twins, 75 twin pairs (150 individuals) were monozygotic and 28 pairs (56 individuals) were dizygotic. Social role function was assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Depressive symptoms were measured by the 15-item version of the Geriatric Depression Scale. Relative importance of genes and environments for the phenotypes was calculated using structural equation analyses. Our results show that genetic influence was the major contributor to the relationship between social role function and depressive symptoms, and non-shared environmental influence was important for overall variation in each trait. We concluded that focusing on a non-shared environment is an essential approach for maintaining social role function and psychological well-being. It is suggested that treatments specific to depressive symptoms are more effective than indirect intervention targeting social role function. © 2011 The Authors. Psychogeriatrics © 2011 Japanese Psychogeriatric Society.

Reared-Apart Chinese Twins: Chance Discovery/Twin-Based Research: Twin Study of Media Use; Twin Relations Over the Life Span; Breast-Feeding Opposite-Sex Twins/Print and Online Media: Twins in Fashion; Second Twin Pair Born to Tennis Star; Twin Primes; Twin Pandas.

PubMed

Segal, Nancy L

2017-04-01

A January 2017 reunion of 10-year-old reared-apart Chinese twin girls was captured live on ABC's morning talk show Good Morning America, and rebroadcast on their evening news program Nightline. The twins' similarities and differences, and their participation in ongoing research will be described. This story is followed by reviews of twin research concerning genetic and environmental influences on media use, twin relations across the lifespan and the breast-feeding of opposite-sex twins. Popular interest items include twins in fashion, the second twin pair born to an internationally renowned tennis star, twin primes and twin pandas.

Unraveling Genetic and Environmental Components of Early Literacy: A Twin Study

ERIC Educational Resources Information Center

Bus, A. G.; Out, D.

2009-01-01

Even though the acquisition of early literacy skills obviously depends on stimuli and incentives in children's environment we may expect that genes define the constraints for acquiring some or all early literacy skills. Therefore behavior genetic analyses were carried out on twin data including 27 identical and 39 same sex dizygotic twins, 4 years…

A twin study of erectile dysfunction.

PubMed

Fischer, Mary E; Vitek, Mary Ellen; Hedeker, Don; Henderson, William G; Jacobsen, Steven J; Goldberg, Jack

2004-01-26

The extent of genetic influence on erectile dysfunction (ED) is unknown. This study determines the contribution of heredity to ED in a sample of middle-aged men. A classical twin study was conducted in the Vietnam Era Twin Registry, a national sample of male-male pairs (mean birth year, 1949) who served on active duty during the Vietnam era (1965-1975). A 1999 male health survey was completed by 890 monozygotic (MZ) and 619 dizygotic (DZ) pairs. The prevalence and heritability of 2 self-report indicators of ED, difficulty in having an erection and in maintaining an erection, are estimated. The prevalence of difficulty in having an erection is 23.3% and in maintaining an erection is 26.7%. Twin correlations for dysfunction in having an erection are 0.35 (95% confidence interval [CI], 0.28-0.41) in MZ and 0.17 (95% CI, 0.09-0.27) in DZ pairs. For dysfunction in maintaining an erection, the twin correlations in MZ and DZ pairs are 0.39 (95% CI, 0.32-0.45) and 0.18 (95% CI, 0.09-0.27), respectively. The estimated heritability of liability for dysfunction in having an erection is 35% and in maintaining an erection is 42%. The heritable influence on ED remained significant after adjustment for ED risk factors. The present study demonstrates an ED-specific genetic component that is independent of genetic influences from numerous ED risk factors. The results suggest that future molecular genetic studies to identify ED-related polymorphisms are warranted.

Gender identity disorder: general overview and surgical treatment for vaginoplasty in male-to-female transsexuals.

PubMed

Selvaggi, Gennaro; Ceulemans, Peter; De Cuypere, Griet; VanLanduyt, Koen; Blondeel, Phillip; Hamdi, Moustapha; Bowman, Cameron; Monstrey, Stan

2005-11-01

After studying this article, the participant should be able to discuss: 1. The terminology related to male-to-female gender dysphoria. 2. The different theories regarding cause, epidemiology, and treatment of gender dysphoria. 3. The surgical goals of sex reassignment surgery in male-to-female transsexualism. 4. The surgical techniques available for sex reassignment surgery in male-to-female transsexualism. Gender identity disorder (previously "transsexualism") is the term used for individuals who show a strong and persistent cross-gender identification and a persistent discomfort with their anatomical sex, as manifested by a preoccupation with getting rid of one's sex characteristics, or the belief of being born in the wrong sex. Since 1978, the Harry Benjamin International Gender Dysphoria Association (in honor of Dr. Harry Benjamin, one of the first physicians who made many clinicians aware of the potential benefits of sex reassignment surgery) has played a major role in the research and treatment of gender identity disorder, publishing the Standards of Care for Gender Dysphoric Persons. The authors performed an overview of the terminology related to male-to-female gender identity disorder; the different theories regarding cause, epidemiology, and treatment; the goals expected; and the surgical technique available for sex reassignment surgery in male-to-female transsexualism. Surgical techniques available for sex reassignment surgery in male-to-female transsexualism, with advantages and disadvantages offered by each technique, are reviewed. Other feminizing nongenital operative interventions are also examined. This review describes recent etiopathogenetic theories and actual guidelines on the treatment of the gender identity disorder in male-to-female transsexuals; the penile-scrotal skin flap technique is considered the state of the art for vaginoplasty in male-to-female transsexuals, whereas other techniques (rectosigmoid flap, local flaps, and isolated skin

Sex difference in leukocyte telomere length is ablated in opposite-sex co-twins

PubMed Central

Benetos, Athanase; Dalgård, Christine; Labat, Carlos; Kark, Jeremy D; Verhulst, Simon; Christensen, Kaare; Kimura, Masayuki; Horvath, Kent; Kyvik, Kirsten Ohm; Aviv, Abraham

2014-01-01

Background: In eutherian mammals and in humans, the female fetus may be masculinized while sharing the intra-uterine environment with a male fetus. Telomere length (TL), as expressed in leukocytes, is heritable and is longer in women than in men. The main determinant of leukocyte TL (LTL) is LTL at birth. However, LTL is modified by age-dependent attrition. Methods: We studied LTL dynamics (LTL and its attrition) in adult same-sex (monozygotic, n = 268; dizygotic, n = 308) twins and opposite-sex (n = 144) twins. LTL was measured by Southern blots of the terminal restriction fragments. Results: We observed that in same-sex (both monozygotic and dizygotic) twins, as reported in singletons, LTL was longer in females than in males [estimate ± standard error (SE):163 ± 63 bp, P < 0.01]. However, in opposite-sex twins, female LTL was indistinguishable from that of males (−31 ± 52 bp, P = 0.6), whereas male LTL was not affected. Findings were similar when the comparison was restricted to opposite-sex and same-sex dizygotic twins (females relative to males: same-sex: 188 ± 90 bp, P < 0.05; other-sex: −32 ± 64 bp, P = 0.6). Conclusions: These findings are compatible with masculinization of the female fetus in opposite-sex twins. They suggest that the sex difference in LTL, seen in the general population, is largely determined in utero, perhaps by the intrauterine hormonal environment. Further studies in newborn twins are warranted to test this thesis. PMID:25056338

The impact of sleep duration on adolescent development: a genetically informed analysis of identical twin pairs.

PubMed

Barnes, J C; Meldrum, Ryan C

2015-02-01

Recent work provides evidence that reduced sleep duration has detrimental effects on a range of developmentally related outcomes during adolescence. Yet, the potential confounding influence of genetic and shared environmental effects has not been sufficiently addressed. This study addresses this issue by analyzing cross-sectional data from the twin sub-sample of the first wave of the National Longitudinal Study of Adolescent Health [N ≈ 287 MZ (monozygotic) twin pairs; 50% male; 22% Black; mean age = 15.75]. Associations between sleep duration (measured through two different strategies, one tapping number of hours slept at night and the other measuring weeknight bedtimes) and seven outcomes (self-control, depressive symptoms, suicidal ideation, body mass index, violent delinquency, non-violent delinquency, and drug use) were estimated. Consistent with prior research, associations between sleep duration and several outcomes were statistically significant when using standard social science analytic methods. Yet, when employing a methodology that accounts for genetic and shared environmental influences, some of these associations were reduced to non-significance. Still, two consistent associations remained in that participants who reported sleeping fewer hours at night (or who reported later bedtimes) exhibited lower levels of self-control and more depressive symptoms. Implications of the findings and directions for future research are discussed.

Twin-to-twin transfusion syndrome

MedlinePlus

... this page: //medlineplus.gov/ency/article/001595.htm Twin-to-twin transfusion syndrome To use the sharing features on this page, please enable JavaScript. Twin-to-twin transfusion syndrome is a rare condition ...

Risk Factors Influencing Smoking Behavior: A Turkish Twin Study

PubMed Central

Öncel, Sevgi Yurt; Dick, Danielle M.; Maes, Hermine H.; Alıev, Fazil

2015-01-01

Aim In this study, we introduce the first twin study in Turkey, focusing on smoking behavior, and laying the foundation to register all twins born in Turkey for research purposes. Using Turkish twins will contribute to our understanding of health problems in the context of cultural differences. Materials and methods We assessed 309 twin pairs (339 males and 279 females) aged between 15 and 45 years living in the Kırıkkale and Ankara regions of Turkey, and administered a health and lifestyle interview that included questions about smoking status and smoking history. We analyzed the data using descriptive statistics, t-tests, chi-square tests, and bivariate and multivariate clustered logistic regression. In addition, we fit bivariate Structural Equation Models (SEM) to determine contributions of latent genetic and environmental factors to smoking outcomes in this sample. Results One hundred seventy-eight participants (28.8%) were identified as smokers, smoking every day for a month or longer, of whom 79.2% were males and 20.8% were females. Mean values for number of cigarettes per day and the Fagerstrom Test of Nicotine Dependence (FTND; Fagerstrom, 1978) score were higher in males than in females, and age of onset was earlier in males. There was a significant positive correlation between the FTND score and number of cigarettes smoked per day, and a significant negative correlation between both variables and age at onset of smoking. Our study showed that gender, presence of a smoking twin in the family, age, alcohol use, marital status, daily sports activities, and feeling moody all played a significant role in smoking behavior among twins. The twin analysis suggested that 79.5% of the liability to FTND was influenced by genetic factors and 20.5% by unique environment, while familial resemblance for smoking initiation was best explained by common environmental factors. Conclusions Marked differences in the prevalence of smoking behavior in men versus women were

Use of embryo transfer seven days after artificial insemination or transferring identical demi-embryos to increase twinning in beef cattle.

PubMed

Dahlen, C R; DiCostanzo, A; Spell, A R; Lamb, G C

2012-12-01

Our objectives were to determine pregnancy rate, fetal loss, and number of calves born in beef cattle after a fixed-time transfer of an embryo 7 d after a fixed-time artificial insemination (TAI) of cows (Exp. 1) and after transfer of 2 demi-embryos into a single heifer recipient (Exp. 2). In Exp. 1 after synchronization of ovulation, during 2 yr, 297 suckled beef cows were assigned randomly to 1 of 3 treatments: 1) on d 2 cows received a single TAI (TAI-2; n = 99), 2) a fixed-time direct transfer, frozen and thawed embryo placed in the uterine horn ipsilateral to the ovary containing a corpus luteum (CL) on d 9 embryo transfer (ET-9; n = 99), or 3) cows received TAI on d 2 and a frozen and thawed direct transfer embryo placed in the uterine horn ipsilateral to the ovary containing a CL on d 9 (TWIN) treatments (n = 99). Fetal number and viability were determined with ultrasonography at 33 to 35 d and 90 to 100 d after insemination. In Exp. 2, 74 crossbred recipient heifers were assigned randomly to receive either 1) a single whole fresh embryo (WHOLE; n = 37) or 2) 2 identical fresh demi-embryos (SPLIT; n = 37) in the uterine horn ipsilateral to the CL 7 d after an observed estrus. Ultrasonography was used on d 33, 69, and 108 to determine presence and number of embryos or fetuses. Palpation per rectum was used to determine pregnancy status on d 180 of gestation and number of live calves was recorded at birth. In Exp. 1 pregnancy rates on d 30 to 35 were greater (P < 0.05) for TWIN- (48.5%) and TAI-2- (47.5%) than for ET-9- (33.3%) treated cows. Of the 48 pregnant cows in the TWIN treatment, 21 were twin pregnancies whereas there was 1 twin pregnancy in the TAI-2 treatment. As a result, TWIN cows had more fetuses (P < 0.05) as a proportion of all treated cows (69.7%) than TAI-2- (48.5%) or ET-9-(33.3%) treated cows, and cows in the TWIN treatment gave birth to more (P < 0.01) calves (n = 55) compared with cows in the ET treatment (n = 23) whereas cows in the TAI-2

MINORITY STRESS, POSITIVE IDENTITY DEVELOPMENT, AND DEPRESSIVE SYMPTOMS: IMPLICATIONS FOR RESILIENCE AMONG SEXUAL MINORITY MALE YOUTH.

PubMed

Bruce, Douglas; Harper, Gary W; Bauermeister, Jose A

2015-09-01

Minority stress processes have been shown to have significant associations with negative mental health outcomes among sexual minority populations. Given that adversity may be experienced growing up as a sexual minority in heteronormative, if not heterosexist, environments, our research on resilience among sexual minority male youth proposes that positive identity development may buffer the effects of a range of minority stress processes. An ethnically diverse sample of 200 sexual minority males ages 16-24 (mean age, 20.9 years) was recruited using mixed recruitment methods. We developed and tested two new measures: concealment stress during adolescence and sexual minority-related positive identity development. We then tested a path model that assessed the effects of minority stressors, positive identity development, and social support on major depressive symptoms. Experience of stigma was associated with internalized homophobia (β=.138, p<.05) and major depressive symptoms (β=1.076, OR=2.933, p<.001), and internalized homophobia partially mediated experience's effects on major depression (β=.773, OR=2.167, p<.001). Concealment stress was associated with positive identity development (β=.155, p<.05) and internalized homophobia (β=.418, p<.001), and positive identity development partially mediated concealment stress's effects on internalized homophobia (β=-.527, p<.001). Concealment stress demonstrated a direct effect on major depression (β=1.400, OR=4.056, p<.001), and indirect paths to social support through positive identity development. With these results, we offer an exploratory model that empirically identifies significant paths among minority stress dimensions, positive identity development, and major depressive symptoms. This study helps further our understanding of minority stress, identity development, and resources of resilience among sexual minority male youth.

Committed White Male Teachers and Identifications: Toward Creative Identifications and a "Second Wave" of White Identity Studies

ERIC Educational Resources Information Center

Jupp, James C.; Slattery, G. Patrick, Jr.

2010-01-01

Committed White male teachers of inner-city students seeks to supersede previous research on White teacher and other White identities by narrating respondents' "creative identifications" and initiating a "second wave" of White identity studies. This research reflection articulates complex, viable, and creative White identities, reconceptualized…

Racial Identity and the MMPI in African American Male College Students.

ERIC Educational Resources Information Center

Whatley, P. Richard; Allen, James; Dana, Richard H.

2003-01-01

Examines the relation of the Minnesota Multiphasic Personality Inventory (MMPI) to the Racial Identity Attitude Scale-Black, Short Form (RIAS-B) was examined among 50 African American male college students Results indicated RIAS-B scale scores functioned as predictors of MMPI scale scores. Implications of these findings for MMPI-2 research with…

The spread of substance use and delinquency between adolescent twins.

PubMed

Laursen, Brett; Hartl, Amy C; Vitaro, Frank; Brendgen, Mara; Dionne, Ginette; Boivin, Michel

2017-02-01

This investigation examines the spread of problem behaviors (substance use and delinquency) between twin siblings. A sample of 628 twins (151 male twin pairs and 163 female twin pairs) drawn from the Quebec Newborn Twin Study completed inventories describing delinquency and substance use at ages 13, 14, and 15. A 3-wave longitudinal actor-partner interdependence model (APIM) identified avenues whereby problem behaviors spread from one twin to another. Problems did not spread directly between twins across domains. Instead, 2 indirect pathways were identified: (a) Problems first spread interindividually (between twins) within a behavioral domain, then spread intraindividually (within twins) across behavioral domains (e.g., Twin A delinquency → Twin B delinquency → Twin B substance use); and (b) problems first spread intraindividually (within twins) across behavioral domains, then spread interindividually (between twins) within a behavioral domain (e.g., Twin A delinquency → Twin A substance use → Twin B substance use). Controls for genetic effects, gene-environment correlations, friend substance use and delinquency, and parenting behaviors increase confidence in the conclusion that twin siblings uniquely contribute to the spread of problem behaviors during adolescence. Twin sibling influence is a risk factor for illicit substance use, both because substance use by one twin predicts substance use by the other twin, but also because delinquency in one twin predicts delinquency in the other twin, which then gives rise to greater substance use. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Do ewes born with a male co-twin have greater longevity with lambing over time?

USDA-ARS?s Scientific Manuscript database

Based on a recent analysis of historical records, ewes born co-twin to a ram had greater lifetime reproductive performance than ewes born co-twin to a ewe. We are interested in determining what component(s) of lifetime reproductive performance may be associated with a ewe’s co-twin sex. As an initi...

Evaluation of Treadmill Exercise in a Lower Body Negative Pressure Chamber as a Countermeasure for Weightlessness-Induced Bone Loss: a Bed Rest Study with Identical Twins

NASA Technical Reports Server (NTRS)

Smith, Scott M.; Davis-Street, Janis E.; Fesperman, J. Vernell; Calkins, D. S.; Bawa, Maneesh; Macias, Brandon R.; Meyer, R. Scott; Hargens, Alan R.

2003-01-01

Counteracting bone loss is required for future space exploration. We evaluated the ability of treadmill exercise in a LBNP chamber to counteract bone loss in a 30-day bed rest study. Eight pairs of identical twins were randomly assigned to sedentary control or exercise groups. Exercise within LBNP decreased the bone resorption caused by bed rest and may provide a countermeasure for spaceflight. INTRODUCTION: Bone loss is one of the greatest physiological challenges for extended-duration space missions. The ability of exercise to counteract weightlessness-induced bone loss has been studied extensively, but to date, it has proven ineffective. We evaluated the effectiveness of a combination of two countermeasures-treadmill exercise while inside a lower body negative pressure (LBNP) chamber-on bone loss during a 30-day bed rest study. MATERIALS AND METHODS: Eight pairs of identical twins were randomized into sedentary (SED) or exercise/LBNP (EX/LBNP) groups. Blood and urine samples were collected before, several times during, and after the 30-day bed rest period. These samples were analyzed for markers of bone and calcium metabolism. Repeated measures ANOVA was used to determine statistical significance. Because identical twins were used, both time and group were treated as repeated variables. RESULTS: Markers of bone resorption were increased during bed rest in samples from sedentary subjects, including the collagen cross-links and serum and urinary calcium concentrations. For N-telopeptide and deoxypyridinoline, there were significant (p < 0.05) interactions between group (SED versus EX/LBNP) and phase of the study (sample collection point). Pyridinium cross-links were increased above pre-bed rest levels in both groups, but the EX/LBNP group had a smaller increase than the SED group. Markers of bone formation were unchanged by bed rest in both groups. CONCLUSIONS: These data show that this weight-bearing exercise combined with LBNP ameliorates some of the negative

Anorexia and bulimia nervosa in same-sex and opposite-sex twins: lack of association with twin type in a nationwide study of Finnish twins.

PubMed

Raevuori, Anu; Kaprio, Jaakko; Hoek, Hans W; Sihvola, Elina; Rissanen, Aila; Keski-Rahkonen, Anna

2008-12-01

The authors tested the hypothesis that either prenatal feminization or masculinization hormone influences in utero or later socialization affects the risk for anorexia and bulimia nervosa and disordered eating in members of opposite-sex twin pairs. Finnish twins (N=2,426 women, N=1,962 men with known zygosity) from birth cohorts born 1974-1979 were assessed at age 22 to 28 years with a questionnaire for eating disorder symptoms. Based on the questionnaire screen, women (N=292), men (N=53), and their cotwins were interviewed to assess diagnoses of anorexia nervosa and bulimia nervosa (per DSM-IV and broad criteria). In women from opposite-sex twin pairs, the prevalence of DSM-IV or broad anorexia nervosa was not significantly different than that of women from monozygotic pairs or same-sex dizygotic pairs. Of the five male anorexia nervosa probands, only one was from an opposite-sex twin pair. Bulimia nervosa in men was too rare to be assessed by zygosity; the prevalence of DSM-IV or broad bulimia nervosa did not differ in women from opposite- versus same-sex twin pairs. In both sexes, the overall profile of indicators on eating disorders was rather similar between individuals from opposite- and same-sex pairs. The authors found little evidence that the risk for anorexia nervosa, bulimia nervosa, or disordered eating was associated with zygosity or sex composition of twin pairs, thus making it unlikely that in utero femininization or masculinization or socialization effects of growing up with an opposite-sex twin have a major influence on the later development of eating disorders.

Incidental brain MRI findings in an autism twin study.

PubMed

Monterrey, Julio C; Philips, Jennifer; Cleveland, Sue; Tanaka, Serena; Barnes, Patrick; Hallmayer, Joachim F; Reiss, Alan L; Lazzeroni, Laura C; Hardan, Antonio Y

2017-01-01

Brain magnetic resonance imaging (MRI) studies suggest the prevalence of asymptomatic "incidental" findings (IF) in autism spectrum disorder (ASD) is similar to that of neurotypically developing (NT) controls. However, given the causes of IF may include both genetic and environmental factors, a twin study would facilitate comparing brain IF between ASD and NT subjects. MRI scans were examined to assess the prevalence of brain IF in twin "case pairs" (at least one twin with diagnosis of ASD) and twin "control pairs" (NT). Fifty case pairs and thirty-two control pairs were analyzed. IF were found in 68% of subjects with ASD, 71% of unaffected ASD siblings, and in 58% of control subjects (P = 0.4). IF requiring clinical follow-up occurred more frequently in subjects with ASD compared to NT controls (17% vs. 5%, respectively; P = 0.02). The concordance rate of IF in twins was 83%. A mixed effects model found younger age, male sex, and "family environment" to be significantly associated with IF. There was no difference in the prevalence rate of IF between ASD subjects and NT controls. More IF required clinical follow-up in ASD subjects compared to NT controls. The prevalence rate of IF observed in this twin study was higher than rates previously reported in singleton studies. Our results suggest the shared environment of twins - perhaps in utero - increases the risk of brain IF. Brain MRI in the initial work-up of ASD may be indicated in twins, especially in males. Autism Res 2017, 10: 113-120. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

MINORITY STRESS, POSITIVE IDENTITY DEVELOPMENT, AND DEPRESSIVE SYMPTOMS: IMPLICATIONS FOR RESILIENCE AMONG SEXUAL MINORITY MALE YOUTH

PubMed Central

Bruce, Douglas; Harper, Gary W.; Bauermeister, Jose A.

2015-01-01

Introduction Minority stress processes have been shown to have significant associations with negative mental health outcomes among sexual minority populations. Given that adversity may be experienced growing up as a sexual minority in heteronormative, if not heterosexist, environments, our research on resilience among sexual minority male youth proposes that positive identity development may buffer the effects of a range of minority stress processes. Methods An ethnically diverse sample of 200 sexual minority males ages 16–24 (mean age, 20.9 years) was recruited using mixed recruitment methods. We developed and tested two new measures: concealment stress during adolescence and sexual minority-related positive identity development. We then tested a path model that assessed the effects of minority stressors, positive identity development, and social support on major depressive symptoms. Results Experience of stigma was associated with internalized homophobia (β=.138, p<.05) and major depressive symptoms (β=1.076, OR=2.933, p<.001), and internalized homophobia partially mediated experience’s effects on major depression (β=.773, OR=2.167, p<.001). Concealment stress was associated with positive identity development (β=.155, p<.05) and internalized homophobia (β=.418, p<.001), and positive identity development partially mediated concealment stress’s effects on internalized homophobia (β=−.527, p<.001). Concealment stress demonstrated a direct effect on major depression (β=1.400, OR=4.056, p<.001), and indirect paths to social support through positive identity development. Conclusions With these results, we offer an exploratory model that empirically identifies significant paths among minority stress dimensions, positive identity development, and major depressive symptoms. This study helps further our understanding of minority stress, identity development, and resources of resilience among sexual minority male youth. PMID:26478901

Two wide-angle imaging neutral-atom spectrometers (TWINS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

McComas, D.J.; Blake, B.; Burch, J.

1998-11-01

Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) is a revolutionary new mission designed to stereoscopically image the magnetosphere in charge exchange neutral atoms for the first time. The authors propose to fly two identical TWINS instruments as a mission of opportunity on two widely-spaced high-altitude, high-inclination US Government spacecraft. Because the spacecraft are funded independently, TWINS can provide a vast quantity of high priority science observations (as identified in an ongoing new missions concept study and the Sun-Earth Connections Roadmap) at a small fraction of the cost of a dedicated mission. Because stereo observations of the near-Earth space environs will providemore » a particularly graphic means for visualizing the magnetosphere in action, and because of the dedication and commitment of the investigator team to the principles of carrying space science to the broader audience, TWINS will also be an outstanding tool for public education and outreach.« less

The Vietnam Era Twin Registry: a resource for medical research.

PubMed Central

Henderson, W G; Eisen, S; Goldberg, J; True, W R; Barnes, J E; Vitek, M E

1990-01-01

The Vietnam Era Twin Registry consists of 4,774 male-male twin pairs born between 1939 and 1957 with both brothers having served in the United States military during the Vietnam War. The registry was originally developed to provide the best control group for Vietnam-exposed servicemen to study the long-term health consequences of service in Vietnam. Recognizing the potential value of the registry for other areas of medical research, the Department of Veterans Affairs in 1988 opened the registry for use by both VA and non-VA investigators. The existence of centralized VA data bases for deaths and VA hospitalizations will strengthen future followup of the twins. This article describes the characteristics of the registry population and the process for accessing the registry. PMID:2116638

The Internet's Multiple Roles in Facilitating the Sexual Orientation Identity Development of Gay and Bisexual Male Adolescents.

PubMed

Harper, Gary W; Serrano, Pedro A; Bruce, Douglas; Bauermeister, Jose A

2016-09-01

One emerging avenue for the exploration of adolescents' sexual orientation identity development is the Internet, since it allows for varying degrees of anonymity and exploration. The purpose of this phenomenological study was to examine the role of the Internet in facilitating the sexual orientation identity development process of gay and bisexual male adolescents. Qualitative interviews were conducted with an ethnically diverse sample of 63 gay/bisexual male adolescents (ages 15-23). Participants reported using a range of Internet applications as they explored and came to accept their sexual orientation identity, with the intended purpose and degree of anonymity desired determining which applications were used. Youth reported that the Internet provided a range of functions with regard to the exploration and acceptance of their sexual orientation identity, including (1) increasing self-awareness of sexual orientation identity, (2) learning about gay/bisexual community life, (3) communicating with other gay/bisexual people, (4) meeting other gay/bisexual people, (5) finding comfort and acceptance with sexual orientation, and (6) facilitating the coming out process. Future research and practice may explore the Internet as a platform for promoting the healthy development of gay and bisexual male adolescents by providing a developmentally and culturally appropriate venue for the exploration and subsequent commitment to an integrated sexual orientation identity. © The Author(s) 2015.

Finding "Los Científicos" within: Latino Male Science Identity Development in the First College Semester

ERIC Educational Resources Information Center

Lu, Charles

2015-01-01

Latino males are the lowest male ethnic subgroup to attain a four-year STEM college degree. This phenomenological qualitative research study used two rounds of interviews with twelve Latino male students in Central Texas to examine their first semester science experiences using a science identity framework. Findings indicate that developing a…

Academic performance of opposite-sex and same-sex twins in adolescence: A Danish national cohort study

PubMed Central

Petersen, Inge; Johnson, Wendy; Christensen, Kaare

2015-01-01

Testosterone is an important hormone in the sexual differentiation of the brain, contributing to differences in cognitive abilities between males and females. For instance, studies in clinical populations such as females with congenital adrenal hyperplasia (CAH) who are exposed to high levels of androgens in utero support arguments for prenatal testosterone effects on characteristics such as visuospatial cognition and behaviour. The comparison of opposite-sex (OS) and same-sex (SS) twin pairs can be used to help establish the role of prenatal testosterone. However, although some twin studies confirm a masculinizing effect of a male co-twin regarding for instance perception and cognition it remains unclear whether intra-uterine hormone transfer exists in humans. Our aim was to test the potential influences of testosterone on academic performance in OS twins. We compared ninth-grade test scores and teacher ratings of OS (n = 1812) and SS (n = 4054) twins as well as of twins and singletons (n = 13,900) in mathematics, physics/chemistry, Danish, and English. We found that males had significantly higher test scores in mathematics than females (.06–.15 SD), whereas females performed better in Danish (.33–.49 SD), English (.20 SD), and neatness (.45–.64 SD). However, we did not find that OS females performed better in mathematics than SS and singleton females, nor did they perform worse either in Danish or English. Scores for OS and SS males were similar in all topics. In conclusion, this study did not provide evidence for a masculinization of female twins with male co-twins with regard to academic performance in adolescence. PMID:25655669

Academic performance of opposite-sex and same-sex twins in adolescence: A Danish national cohort study.

PubMed

Ahrenfeldt, Linda; Petersen, Inge; Johnson, Wendy; Christensen, Kaare

2015-03-01

Testosterone is an important hormone in the sexual differentiation of the brain, contributing to differences in cognitive abilities between males and females. For instance, studies in clinical populations such as females with congenital adrenal hyperplasia (CAH) who are exposed to high levels of androgens in utero support arguments for prenatal testosterone effects on characteristics such as visuospatial cognition and behaviour. The comparison of opposite-sex (OS) and same-sex (SS) twin pairs can be used to help establish the role of prenatal testosterone. However, although some twin studies confirm a masculinizing effect of a male co-twin regarding for instance perception and cognition it remains unclear whether intra-uterine hormone transfer exists in humans. Our aim was to test the potential influences of testosterone on academic performance in OS twins. We compared ninth-grade test scores and teacher ratings of OS (n=1812) and SS (n=4054) twins as well as of twins and singletons (n=13,900) in mathematics, physics/chemistry, Danish, and English. We found that males had significantly higher test scores in mathematics than females (.06-.15 SD), whereas females performed better in Danish (.33-.49 SD), English (.20 SD), and neatness (.45-.64 SD). However, we did not find that OS females performed better in mathematics than SS and singleton females, nor did they perform worse either in Danish or English. Scores for OS and SS males were similar in all topics. In conclusion, this study did not provide evidence for a masculinization of female twins with male co-twins with regard to academic performance in adolescence. Copyright © 2015 Elsevier Inc. All rights reserved.

Posttraumatic Stress Disorder, Combat Exposure, and Carotid Intima-Media Thickness in Male Twins

PubMed Central

Goetz, Margarethe; Shah, Amit; Goldberg, Jack; Cheema, Faiz; Shallenberger, Lucy; Murrah, Nancy V.; Bremner, J. Douglas; Vaccarino, Viola

2014-01-01

Posttraumatic stress disorder (PTSD) is associated with an increased risk of ischemic heart disease, though the pathophysiologic mechanisms remain unclear. Carotid artery intima-media thickness (CIMT) is a measure of subclinical atherosclerosis. We examined whether PTSD and combat exposure were associated with CIMT in Vietnam War–era twins after controlling for shared genetic and childhood factors. Between 2002 and 2010, we studied 465 middle-aged twins from the Vietnam Era Twin Registry who were free from cardiovascular disease. PTSD was diagnosed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and CIMT was measured by ultrasound. Mixed-effects regression models were used to examine individual, between-pair, and within-pair associations. Approximately 13% of participants met the criteria for PTSD, and 45% served in the Vietnam Theater. PTSD was associated with 32.7 μm higher CIMT (95% confidence interval (CI): 0.9, 64.5) after adjustment for confounders. The average CIMT for the pair increased by 59.7 μm for each additional twin with PTSD (95% CI: 15.9, 104.2). We found no significant within-pair differences in CIMT when comparing PTSD-discordant co-twins. Results for combat exposure were similar, but its association with CIMT weakened after adjustment for PTSD (95% CI: 7.0, 45.3). Among Vietnam War–era veterans, combat exposure and PTSD are associated with CIMT, though the associations are largely mediated by shared childhood factors. PMID:25301813

Australian national birthweight percentiles by sex and gestational age for twins, 2001-2010.

PubMed

Li, Zhuoyang; Umstad, Mark P; Hilder, Lisa; Xu, Fenglian; Sullivan, Elizabeth A

2015-10-08

Birthweight remains one of the strongest predictors of perinatal mortality and disability. Birthweight percentiles form a reference that allows the detection of neonates at higher risk of neonatal and postneonatal morbidity. The aim of the study is to present updated national birthweight percentiles by gestational age for male and female twins born in Australia. Population data were extracted from the Australian National Perinatal Data Collection for twins born in Australia between 2001 and 2010. A total of 43,833 women gave birth to 87,666 twins in Australia which were included in the study analysis. Implausible birthweights were excluded using Tukey's methodology based on the interquartile range. Univariate analysis was used to examine the birthweight percentiles for liveborn twins born between 20 and 42 weeks gestation. Birthweight percentiles by gestational age were calculated for 85,925 live births (43,153 males and 42,706 females). Of these infants, 53.6% were born preterm (birth before 37 completed weeks of gestation) while 50.2% were low birthweight (<2500 g) and 8.7% were very low birthweight (<1500 g). The mean birthweight decreased from 2462 g in 2001 to 2440 g in 2010 for male twins, compared with 2485 g in 1991-94. For female twins, the mean birthweight decreased from 2375 g in 2001 to 2338 g in 2010, compared with 2382 g in 1991-94. The birthweight percentiles provide clinicians and researchers with up-to-date population norms of birthweight percentiles for twins in Australia.

Mental health and sexual identity in a sample of male sex workers in the Czech Republic.

PubMed

Bar-Johnson, Michael; Weiss, Petr

2014-09-20

Previous qualitative research has examined male sex workers in the Czech Republic, but this mapping study is the first to investigate male sex work in a quantitative research design and focus on the mental health of these sex workers. This study also examines male sex workers' mental health problems in relation to their sexual identity or orientation. A sample of Czech male sex workers (N=40) were examined on a range of sexual and psychological variables using a quantitative survey administered face-to-face. The study employed locally validated versions of Beck's Depression Inventory and Zung's Self-Report Anxiety Scale. The results indicate that for homosexuals, working as a male sex worker is not related to any serious mental health problems. However, those identifying as heterosexual and bisexual more frequently reported symptoms of depression and bisexuals showed significantly more anxiety. These findings suggest sexual identity is an important issue to consider when addressing the mental health needs of this population.

The Internet’s Multiple Roles in Facilitating the Sexual Orientation Identity Development of Gay and Bisexual Male Adolescents

PubMed Central

Harper, Gary W.; Serrano, Pedro A.; Bruce, Douglas; Bauermeister, Jose A.

2016-01-01

One emerging avenue for the exploration of adolescents’ sexual orientation identity development is the Internet since it allows for varying degrees of anonymity and exploration. The purpose of this phenomenological study was to examine the role of the Internet in facilitating the sexual orientation identity development process of gay and bisexual male adolescents. Qualitative interviews were conducted with an ethnically diverse sample of 63 gay/bisexual male adolescents (ages 15–23). Participants reported using a range of Internet applications as they explored and came to accept their sexual orientation identity, with the intended purpose and degree of anonymity desired determining which applications were used. Youth reported that the Internet provided a range of functions with regard to the exploration and acceptance of their sexual orientation identity, including: 1) increasing self awareness of sexual orientation identity; 2) learning about gay/bisexual community life; 3) communicating with other gay/bisexual people; 4) meeting other gay/bisexual people; 5) finding comfort and acceptance with sexual orientation; and 6) facilitating the coming out process. Future research and practice may explore the Internet as a platform for promoting the healthy development of gay and bisexual male adolescents by providing a developmentally and culturally appropriate venue for the exploration and subsequent commitment to an integrated sexual orientation identity. PMID:25585861

Male Asian international students' perceived racial discrimination, masculine identity, and subjective masculinity stress: a moderated mediation model.

PubMed

Wong, Y Joel; Tsai, Pei-Chun; Liu, Tao; Zhu, Qingqing; Wei, Meifen

2014-10-01

This study examined male Asian international college students' perceptions of racial discrimination, subjective masculinity stress, centrality of masculine identity, and psychological distress by testing a moderated mediation model. Participants were 160 male Asian international college students from 2 large public universities. Participants' perceived racial discrimination was positively related to their subjective masculinity stress only at high (but not low) levels of masculine identity centrality. Additionally, subjective masculinity stress was positively related to psychological distress, although this association was stronger among those who reported high levels of masculine identity centrality. The authors also detected a moderated mediation effect in which subjective masculinity stress mediated the relationship between perceived racial discrimination and psychological distress only at high (but not low) levels of masculine identity centrality. These findings contribute to the counseling psychology literature by highlighting the connections between race- and gender-related stressors as well as the relevance of masculine identity to an understanding of men's mental health. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Paternal alcoholism and offspring ADHD problems: a children of twins design.

PubMed

Knopik, Valerie S; Jacob, Theodore; Haber, Jon Randolph; Swenson, Lance P; Howell, Donelle N

2009-02-01

A recent Children-of-Female-Twin design suggests that the association between maternal alcohol use disorder and offspring ADHD is due to a combination of genetic and environmental factors, such as prenatal nicotine exposure. We present here a complementary analysis using a Children-of-Male-Twin design examining the association between paternal alcoholism and offspring attention deficit hyperactivity problems (ADHP). Children-of-twins design: offspring were classified into 4 groups of varying genetic and environmental risk based on father and co-twin's alcohol dependence status. Univariate results are suggestive of a genetic association between paternal alcohol dependence and broadly defined offspring ADHP. Specifically, offspring of male twins with a history of DSM-III-R alcohol dependence, as well as offspring of non-alcohol dependent monozygotic twins whose co-twin was alcohol dependent, were significantly more likely to exhibit ADHP than control offspring. However, multivariate models show maternal variables independently predicting increased risk for offspring ADHP and significantly decreased support for a genetic mechanism of parent-to-child transmission. In support of earlier work, maternal variables (i.e., maternal ADHD and prenatal exposure) were strongly associated with child ADHP; however, the role of paternal alcohol dependence influences was not definitive. While genetic transmission may be important, the association between paternal alcohol dependence and child ADHP is more likely to be indirect and a result of several pathways.

The Role of Multiple Identities in Adherence to Medical Appointments among Gay/Bisexual Male Adolescents Living with HIV

PubMed Central

Harper, Gary W.; Fernandez, M. Isabel; Bruce, Douglas; Hosek, Sybil G.; Jacobs, Robin J.

2012-01-01

Adolescents living with HIV require engagement with care providers in order to access the critical medical and psychosocial services they need. The current study sought to explore developmental determinants of adherence to medical appointments as one aspect of engagement in care among a geographically diverse sample of 200 gay/bisexual male adolescents (16–24 years) living with HIV, with a specific focus on ethnic identity, sexual orientation identity, and identity as a young man living with HIV. Ethnic identity affirmation (OR = 0.6; 95% CI: 0.3, 0.9), morality of homosexuality (OR = 1.7; 95% CI: 1.2, 2.5), and HIV-positive identity salience (OR = 1.5; 95% CI: 0.9, 2.4) were associated with significantly higher risk for missed appointments in the past three months. These findings highlight the importance of attending to developmental factors, such as the development of multiple identities, when attempting to increase engagement in care for gay/bisexual male adolescents living with HIV. PMID:22041930

The role of multiple identities in adherence to medical appointments among gay/bisexual male adolescents living with HIV.

PubMed

Harper, Gary W; Fernandez, Isabel M; Bruce, Douglas; Hosek, Sybil G; Jacobs, Robin J

2013-01-01

Adolescents living with HIV require engagement with care providers in order to access the critical medical and psychosocial services they need. The current study sought to explore developmental determinants of adherence to medical appointments as one aspect of engagement in care among a geographically diverse sample of 200 gay/bisexual male adolescents (16-24 years) living with HIV, with a specific focus on ethnic identity, sexual orientation identity, and identity as a young man living with HIV. Ethnic identity affirmation (OR = 0.6; 95% CI: 0.3, 0.9), morality of homosexuality (OR = 1.7; 95% CI: 1.2, 2.5), and HIV-positive identity salience (OR = 1.5; 95% CI: 0.9, 2.4) were associated with significantly higher risk for missed appointments in the past 3 months. These findings highlight the importance of attending to developmental factors, such as the development of multiple identities, when attempting to increase engagement in care for gay/bisexual male adolescents living with HIV.

Hypothalamus, sexual arousal and psychosexual identity in human males: a functional magnetic resonance imaging study.

PubMed

Brunetti, M; Babiloni, C; Ferretti, A; Del Gratta, C; Merla, A; Olivetti Belardinelli, M; Romani, G L

2008-06-01

In a recent functional magnetic resonance imaging study, a complex neural circuit was shown to be involved in human males during sexual arousal [A. Ferretti et al. (2005) Neuroimage, 26, 1086]. At group level, there was a specific correlation between penile erection and activations in anterior cingulate, insula, amygdala, hypothalamus and secondary somatosensory regions. However, it is well known that there are remarkable inter-individual differences in the psychological view and attitude to sex of human males. Therefore, a crucial issue is the relationship among cerebral responses, sexual arousal and psychosexual identity at individual level. To address this issue, 18 healthy male subjects were recruited. Their deep sexual identity (DSI) was assessed following the construct revalidation by M. Olivetti Belardinelli [(1994) Sci. Contrib. Gen. Psychol., 11, 131] of the Franck drawing completion test, a projective test providing, according to this revalidation, quantitative scores on 'accordance/non-accordance' between self-reported and psychological sexual identity. Cerebral activity was evaluated by means of functional magnetic resonance imaging during hard-core erotic movies and sport movies. Results showed a statistically significant positive correlation between the blood oxygen level-dependent signal in bilateral hypothalamus and the Franck drawing completion test score during erotic movies. The higher the blood oxygen level-dependent activation in bilateral hypothalamus, the higher the male DSI profile. These results suggest that, in male subjects, inter-individual differences in the DSI are strongly correlated with blood flow to the bilateral hypothalamus, a dimorphic brain region deeply implicated in instinctual drives including reproduction.

Temporal and inter-task consistency of heart rate reactivity during active psychological challenge: a twin study.

PubMed

Turner, J R; Carroll, D; Sims, J; Hewitt, J K; Kelly, K A

1986-01-01

Heart rate was monitored while 22 pairs of young male monozygotic and 29 pairs of young male dizygotic twins were exposed to a video game and a mental arithmetic task. The heart rate reactions of the monozygotic twins showed much greater concordance than those of the dizygotic twins. Analysis of the data for the 102 individuals demonstrated reliable inter-task consistency of heart rate reaction. In addition, comparison of the heart rate reactions of ten pairs of monozygotic and ten pairs of dizygotic twins who had been tested more than a year earlier and their present reactivities revealed impressive temporal consistency.

Reciprocal Longitudinal Associations Between Adolescent Twin Gambling and Delinquency.

PubMed

Vitaro, Frank; C Hartl, Amy; Laursen, Brett; Brendgen, Mara; Dionne, Ginette; Boivin, Michel

2015-12-01

This study examined sibling influence over gambling involvement and delinquency in a sample of 628 twins (151 male dyads, 163 female dyads). Self-reports of gambling involvement and delinquency were collected for each twin at ages 13, 14 and 15 years. Results revealed evidence of between-twin influence. Higher levels of an adolescent's delinquency predicted an increase in his or her co-twin's delinquency from age 13 to age 14 and from age 14 to age 15. In contrast, gambling behavior was unaffected by the co-twin's gambling involvement. Within-twins, higher initial levels of delinquency predicted a subsequent increase in gambling behavior from age 13 to age 14 and again from age 14 to age 15, and higher initial levels of gambling involvement predicted an increase in delinquency from age 14 to age 15. Between and within siblings effects are discussed in light of the scant literature on (a) sibling influence on gambling, and (b) the links between gambling and delinquency.

Gender mix in twins and fetal growth, length of gestation and adult cancer risk.

PubMed

Luke, Barbara; Hediger, Mary; Min, Sung-Joon; Brown, Morton B; Misiunas, Ruta B; Gonzalez-Quintero, Victor Hugo; Nugent, Clark; Witter, Frank R; Newman, Roger B; Hankins, Gary D V; Grainger, David A; Macones, George A

2005-01-01

This study evaluated the effect of gender mix (the gender combinations of twin pairs) on fetal growth and length of gestation, and reviewed the literature on the long-term effects of this altered fetal milieu on cancer risk. In singletons, it is well established that females weigh less than males at all gestations, averaging 125-135 g less at full term. This gender difference is generally believed to be the result of the effect of androgens on fetal growth. The gender difference in fetal growth is greater before the third trimester and less towards term, with males growing not only more, but also earlier than females. Plurality is a known risk factor for reduced fetal growth and birthweight. Compared with singletons, the mean birthweight percentiles of twins fall substantially (by 10% or more) below the singleton 10th percentile by 28 weeks, below the singleton 50th percentile by 30 weeks, and below the singleton 90th percentile by 34 weeks. In unlike-gender twin pairs, it has been reported that the female prolongs gestation for her brother, resulting in a higher birthweight for the male twin than that of like-gender male twins. Other researchers have demonstrated that females in unlike-gender pairs had higher birthweights than females in like-gender pairs. Analyses from our consortium on 2491 twin pregnancies with known chorionicity showed longer gestations and faster rates of fetal growth in both males and females in unlike-gender pairs compared with like-gender male or female pairs, although these differences were not statistically significant. The post-natal effects for females growing in an androgenic-anabolic environment include increased sensation-seeking behaviour and aggression, lowered visual acuity, more masculine attitudes and masculinising effects of the auditory system and craniofacial growth. In contrast, there is no evidence to suggest that there might be a similar feminising effect on males from unlike-gender pairs. This hormonal exposure in utero

The shaping of masculinity: Revisioning boys turning away from their mothers to construct male gender identity.

PubMed

Diamond, Michael J

2004-04-01

This paper offers an understanding of the nature of the internalization processes involved in the shaping of male gender identity founded on the boy's unique struggles in separating from his mother. The underpinning for the initial development of a sense of masculinity is reconsidered as the author questions the widely held idea of Greenson and Stoller that a boy normatively has to 'dis-identify' from his mother to create his gender identity. Import rather is placed on the conscious and unconscious aspects of the mother's (and father's) pre-oedipal and oedipal relationship with their little boy in order better to understand the nature of the boy's unique identifications and subsequent sense of masculinity. Both the security of the boy's attachment to his mother, in providing the foundation for a transitional turning to an 'other', and the mother's capacity to reflect upon and recognize her own, as well as the father's and her son's, subjectivity and maleness, are crucial in comprehending boys' 'attachment-individuation' process. Likewise, the unconscious paternal and maternal imagos and identifications of both the boy's mother and father, as well as the father's pre-oedipal relationship with his little boy and the boy's mother, are extremely significant in shaping a son's gender identity. The author argues that these early maternal (and paternal) identifications live on in every male and continue to impact the sense of maleness in a dialectical interplay throughout the life span. A maturing gender identity develops from integrating these early, pre-oedipal maternal identifications that no longer need be repudiated nor defensively organized as polarized gender splitting.

Mathematics: Self-Efficacy, Identity, and Achievement among African American Males from the High School Longitudinal Study

ERIC Educational Resources Information Center

Briggs, Calvin

2014-01-01

The purpose of this study was to determine if a relationship existed between mathematics self-efficacy and mathematics identity to mathematics achievement among African American males from High School Longitudinal Study of 2009 (HSLS:09). Subsequently, the extent to which mathematics self-efficacy and mathematics identity accounted for low and…

Gene-Environment Interplay in Twin Models

PubMed Central

Hatemi, Peter K.

2013-01-01

In this article, we respond to Shultziner’s critique that argues that identical twins are more alike not because of genetic similarity, but because they select into more similar environments and respond to stimuli in comparable ways, and that these effects bias twin model estimates to such an extent that they are invalid. The essay further argues that the theory and methods that undergird twin models, as well as the empirical studies which rely upon them, are unaware of these potential biases. We correct this and other misunderstandings in the essay and find that gene-environment (GE) interplay is a well-articulated concept in behavior genetics and political science, operationalized as gene-environment correlation and gene-environment interaction. Both are incorporated into interpretations of the classical twin design (CTD) and estimated in numerous empirical studies through extensions of the CTD. We then conduct simulations to quantify the influence of GE interplay on estimates from the CTD. Due to the criticism’s mischaracterization of the CTD and GE interplay, combined with the absence of any empirical evidence to counter what is presented in the extant literature and this article, we conclude that the critique does not enhance our understanding of the processes that drive political traits, genetic or otherwise. PMID:24808718

eTwinning in Language Learning: The Perspectives of Successful Teachers

ERIC Educational Resources Information Center

Akdemir, Ahmet Selçuk

2017-01-01

This study aims at investigating the effect of eTwinning, an innovative way of cooperative learning, on language teaching. A qualitative research design is preferred in order to explore the experiences of language teachers who have completed successful eTwinning projects. To this end, 7 ELT professionals (4 female, 3 male) from different cities of…

Twin photon pairs in a high-Q silicon microresonator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, Steven; Lu, Xiyuan; Jiang, Wei C.

2015-07-27

We report the generation of high-purity twin photon pairs through cavity-enhanced non-degenerate four-wave mixing (FWM) in a high-Q silicon microdisk resonator. Twin photon pairs are created within the same cavity mode and are consequently expected to be identical in all degrees of freedom. The device is able to produce twin photons at telecommunication wavelengths with a pair generation rate as large as (3.96 ± 0.03) × 10{sup 5} pairs/s, within a narrow bandwidth of 0.72 GHz. A coincidence-to-accidental ratio of 660 ± 62 was measured, the highest value reported to date for twin photon pairs, at a pair generation rate of (2.47 ±more » 0.04) × 10{sup 4} pairs/s. Through careful engineering of the dispersion matching window, we have reduced the ratio of photons resulting from degenerate FWM to non-degenerate FWM to less than 0.15.« less

Investigating the Epigenetic Discrimination of Identical Twins Using Buccal Swabs, Saliva, and Cigarette Butts in the Forensic Setting.

PubMed

Vidaki, Athina; Kalamara, Vivian; Carnero-Montoro, Elena; Spector, Timothy D; Bell, Jordana T; Kayser, Manfred

2018-05-14

Monozygotic (MZ) twins are typically indistinguishable via forensic DNA profiling. Recently, we demonstrated that epigenetic differentiation of MZ twins is feasible; however, proportions of twin differentially methylated CpG sites (tDMSs) identified in reference-type blood DNA were not replicated in trace-type blood DNA. Here we investigated buccal swabs as typical forensic reference material, and saliva and cigarette butts as commonly encountered forensic trace materials. As an analog to a forensic case, we analyzed one MZ twin pair. Epigenome-wide microarray analysis in reference-type buccal DNA revealed 25 candidate tDMSs with >0.5 twin-to-twin differences. MethyLight quantitative PCR (qPCR) of 22 selected tDMSs in trace-type DNA revealed in saliva DNA that six tDMSs (27.3%) had >0.1 twin-to-twin differences, seven (31.8%) had smaller (<0.1) but robustly detected differences, whereas for nine (40.9%) the differences were in the opposite direction relative to the microarray data; for cigarette butt DNA, results were 50%, 22.7%, and 27.3%, respectively. The discrepancies between reference-type and trace-type DNA outcomes can be explained by cell composition differences, method-to-method variation, and other technical reasons including bisulfite conversion inefficiency. Our study highlights the importance of the DNA source and that careful characterization of biological and technical effects is needed before epigenetic MZ twin differentiation is applicable in forensic casework.

Investigation of twin-twin interaction in deformed magnesium alloy

NASA Astrophysics Data System (ADS)

Sun, Qi; Ostapovets, Andriy; Zhang, Xiyan; Tan, Li; Liu, Qing

2018-03-01

Using transmission electron microscopy, we characterised the structures of the boundary caused by the interactions between different ? twin variants that share the same ? zone axis in a deformed magnesium alloy. We found that the twin-twin boundaries can adopt the habit planes that are parallel to the (0 0 0 2) basal plane or the ? prismatic plane or the ? twinning plane of the interacting twins. To investigate the formation mechanism of various twin-twin boundaries, we also performed atomic simulations. The results indicate that the formation of a twin-twin boundary may be related to the reaction of twinning disconnections that glide on the basal-prismatic planes of the interacting twins.

Conjoined Twins: Philosophical Problems and Ethical Challenges

PubMed Central

Savulescu, Julian; Persson, Ingmar

2016-01-01

We examine the philosophical and ethical issues associated with conjoined twins and their surgical separation. In cases in which there is an extensive sharing of organs, but nevertheless two distinguishable functioning brains, there are a number of philosophical and ethical challenges. This is because such conjoined twins: 1. give rise to puzzles concerning our identity, about whether we are identical to something psychological or biological;2. force us to decide whether what matters from an ethical point of view is the biological life of our organisms or the existence of our consciousness or mind;3. raise questions concerning when, if ever, it is morally acceptable to sacrifice one of us to save another;4. force us to reflect on the conditions for ownership of organs and the justification of removal of organs for transplantation which causes the death of the donor;5. raise questions about who should take decisions about life-risking treatments when this cannot be decided by patients themselves. We examine and suggest answers to these questions. PMID:26671962

Monozygotic twin discordant for Down syndrome: mos 47,XX,+21/46,XX and 46,XX.

PubMed

Choi, Sun Ah; Ko, Jung Min; Shin, Choong Ho; Yang, Sei Won; Choi, Jin Sun; Oh, Sun Kyung

2013-08-01

Monozygotic twins, developed from a single zygote, are almost identical in clinical phenotype and concordant karyotypes. Monozygotic twins with discordant karyotypes are thought to be quite rare. Here, we report monochorionic-diamniotic twins discordant for Down syndrome. On findings of prenatal ultrasonography, nuchal translucency thickness was different between twins, and suggested that one of the twins was at high risk for having chromosomal abnormalities including Down syndrome. The twins were monochorionic-diamniotic; therefore, chorionic villi sampling of the common placenta was performed. The karyotype of the chorionic villi cells was 46,XX, and pregnancy was maintained. After delivery, dysmorphic clinical features suggesting Down syndrome were found in one of the twins, while the other twin showed a morphologically normal appearance. Karyotypes of peripheral blood leukocytes were repeatedly normal in the dysmorphic twin; however, the karyotype of skin fibroblasts from the dysmorphic twin indicated Down syndrome mosaicism; 47,XX,+21[99]/46,XX[2]. The karyotype of skin fibroblasts from the morphologically normal twin was 46,XX. Monozygosity of the twins was confirmed by a short tandem repeat analysis using 16 polymorphic markers. A mitotic nondisjunction followed by the twinning would explain the discordant karyotypes between monozygotic twins.

Posttraumatic stress disorder, combat exposure, and carotid intima-media thickness in male twins.

PubMed

Goetz, Margarethe; Shah, Amit; Goldberg, Jack; Cheema, Faiz; Shallenberger, Lucy; Murrah, Nancy V; Bremner, J Douglas; Vaccarino, Viola

2014-11-15

Posttraumatic stress disorder (PTSD) is associated with an increased risk of ischemic heart disease, though the pathophysiologic mechanisms remain unclear. Carotid artery intima-media thickness (CIMT) is a measure of subclinical atherosclerosis. We examined whether PTSD and combat exposure were associated with CIMT in Vietnam War-era twins after controlling for shared genetic and childhood factors. Between 2002 and 2010, we studied 465 middle-aged twins from the Vietnam Era Twin Registry who were free from cardiovascular disease. PTSD was diagnosed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and CIMT was measured by ultrasound. Mixed-effects regression models were used to examine individual, between-pair, and within-pair associations. Approximately 13% of participants met the criteria for PTSD, and 45% served in the Vietnam Theater. PTSD was associated with 32.7 μm higher CIMT (95% confidence interval (CI): 0.9, 64.5) after adjustment for confounders. The average CIMT for the pair increased by 59.7 μm for each additional twin with PTSD (95% CI: 15.9, 104.2). We found no significant within-pair differences in CIMT when comparing PTSD-discordant co-twins. Results for combat exposure were similar, but its association with CIMT weakened after adjustment for PTSD (95% CI: 7.0, 45.3). Among Vietnam War-era veterans, combat exposure and PTSD are associated with CIMT, though the associations are largely mediated by shared childhood factors. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Head Circumferences in Twins with and without Autism Spectrum Disorders

ERIC Educational Resources Information Center

Froehlich, Wendy; Cleveland, Sue; Torres, Andrea; Phillips, Jennifer; Cohen, Brianne; Torigoe, Tiffany; Miller, Janet; Fedele, Angie; Collins, Jack; Smith, Karen; Lotspeich, Linda; Croen, Lisa A.; Ozonoff, Sally; Lajonchere, Clara; Grether, Judith K.; Hallmayer, Joachim

2013-01-01

To determine the genetic relationship between head circumference (HC) and Autism Spectrum Disorders (ASDs). Twin pairs with at least one twin with an ASD were assessed. HCs in affected and unaffected individuals were compared, as were HC correlations in monozygotic and dizygotic pairs. 404 subjects, ages 4-18, were included. 20% of males and 27%…

Sexual and ethnic identity development among gay-bisexual-questioning (GBQ) male ethnic minority adolescents.

PubMed

Jamil, Omar B; Harper, Gary W; Fernandez, M Isabel

2009-07-01

Identity development is a critical task of adolescence and occurs across multiple areas of self-identification. Although research on the identity development process among individuals who are ethnic and sexual minorities has been conducted for individuals who have 1 minority status or the other, few studies have examined these processes in people who are both ethnic and sexual minorities. In this qualitative study, the authors examined the dual identity development processes related to ethnic and sexual identity among gay-bisexual-questioning (GBQ) Latino and African American male adolescents. Results indicated that the processes associated with the development of sexual orientation and ethnic identity occur concurrently. However, the actual processes involved with the development of each identity not only differed, but seemed to be independent of each other because neither process was referenced in the development of the other. Overall, the process of ethnic identity development involved the process of becoming aware of one's ethnic and cultural heritage, whereas sexual identity development involved finding one's own personally relevant sexual orientation label and connecting to that community. The implications of these findings for the development of interventions to assist in the healthy development of GBQ adolescents are discussed.

Sexual and Ethnic Identity Development among Gay/Bisexual/Questioning (GBQ) Male Ethnic Minority Adolescents

PubMed Central

Jamil, Omar B.; Harper, Gary W.; Fernandez, M. Isabel

2010-01-01

Identity development is a critical task of adolescence and occurs across multiple areas of self identification. Though research on the identity development process among individuals who are ethnic and sexual minorities has been conducted for individuals who have one minority status or the other, few studies have examined these processes in persons who are both ethnic and sexual minorities. This qualitative study examined the dual identity development processes related to ethnic and sexual identity among gay/bisexual/questioning (GBQ) Latino and African American male adolescents. Results indicated that the processes associated with the development of sexual orientation and ethnic identity occur concurrently. However, the actual processes involved with the development of each identity not only differed, but seemed to be independent of each other since neither process was referenced in the development of the other. Overall, the process of ethnic identity development involved the process of becoming aware of one’s ethnic and cultural heritage, while sexual identity development involved finding one’s own personally relevant sexual orientation label and connecting to that community. The implications of these findings for the development of interventions to assist in the healthy development of GBQ adolescents are discussed. PMID:19594249

Effects of exercise training and a hypocaloric diet on female monozygotic twins in free-living conditions.

PubMed

Koenigstorfer, Joerg; Schmidt, Walter F J

2011-10-24

This paper aims to examine the similarities in effects of exercise training and a hypocaloric diet within overweight female monozygotic twin pairs and to assess differences in twin partners' responses depending on the timing of exercise bouts and main meals. Six previously untrained twin pairs (aged 20-37 years, body fat 35.8±6.3%) performed an identical exercise program (12 bouts endurance and 8 bouts resistance training) and took part in a nutrition counseling program for a period of 28 days. They pursued one identical goal: to lose body weight and fat. Each twin partner was randomly assigned to one of the two intervention groups: "exercise after dinner" (A) and "exercise before dinner" (B). Subjects followed a hypocaloric diet, supervised by a nutritionist, in free-living conditions. Reductions in body weight, waist and hip circumference, glucose tolerance, mean daily %fat intake, changes in morning resting energy rate and resting metabolic rate showed great variation between twin pairs, but only small variation within twin pairs. Thus, the genetic influence on the changes in most of the examined anthropometric and physiological variables was high. There was no influence of the specific timing on the dependent variables. Copyright © 2011 Elsevier Inc. All rights reserved.

Neurobiology of Gender Identity and Sexual Orientation.

PubMed

Roselli, Charles E

2017-12-06

Sexual identity and sexual orientation are independent components of a person's sexual identity. These dimensions are most often in harmony with each other and with an individual's genital sex, but not always. This review discusses the relationship of sexual identity and sexual orientation to prenatal factors that act to shape the development of the brain and the expression of sexual behaviors in animals and humans. One major influence discussed relates to organizational effects that the early hormone environment exerts on both gender identity and sexual orientation. Evidence that gender identity and sexual orientation are masculinized by prenatal exposure to testosterone and feminized in it absence is drawn from basic research in animals, correlations of biometric indices of androgen exposure and studies of clinical conditions associated with disorders in sexual development. There are, however, important exceptions to this theory that have yet to be resolved. Family and twin studies indicate that genes play a role, but no specific candidate genes have been identified. Evidence that relates to the number of older brothers implicates maternal immune responses as a contributing factor for male sexual orientation. It remains speculative how these influences might relate to each other and interact with postnatal socialization. Nonetheless, despite the many challenges to research in this area, existing empirical evidence makes it clear that there is a significant biological contribution to the development of an individual's sexual identity and sexual orientation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Growth and Development of Dentofacial Complex influenced by Genetic and Environmental Factors using Monozygotic Twins.

PubMed

Manjusha, K K; Jyothindrakumar, K; Nishad, A; Manoj, K Madhav

2017-09-01

The purpose of this study was to determine the possible effects of genetic and environmental factors on dentofacial complex using monozygotic twins. The study sample was made of 21 pairs of monozygotic twins (14 female pairs and seven male pairs) between 10 and 25 years. Pretreatment lateral cephalo-grams were used which were traced and digitized, and various landmarks to determine the anteroposterior and vertical proportions were marked. Samples were divided into two groups. The correlation between groups was found by calculating Pearson's product moment correlation coefficients. The range of the correlation coefficient was from 0.705 to 0.952. Gonial angle showed the highest correlation coefficient (0.952), while saddle angle showed the lowest correlation coefficient (0.705). The growth and development of craniofacial complex is under mutifactorial control. However, genetic influences do tend to play a dominant role. By studying identical twins, we can study about the interaction of the environment with the genes and how it affects the growth and development of the body in general and dentofacial complex in particular. By utilizing twin studies, we can identify whether a particular trait, disease, or disorder is influenced more strongly by genetics or by the environment. Success of orthodontic treatment depends on a proper diagnosis of the problem including its etiological factors. Genetic studies let the orthodontists to understand the effects of genetic and environmental factors in the growth and development of dentofacial complex better and allows to prevent or treat malocclusions and skeletal anomalies in better ways.

Adequacy of Using a Three-Item Questionnaire to Determine Zygosity in Chinese Young Twins.

PubMed

Ho, Connie Suk-Han; Zheng, Mo; Chow, Bonnie Wing-Yin; Wong, Simpson W L; Lim, Cadmon K P; Waye, Mary M Y

2017-03-01

The present study examined the adequacy of a three-item parent questionnaire in determining the zygosity of young Chinese twins and whether there was any association between parent response accuracy and some demographic variables. The sample consisted of 334 pairs of same-sex Chinese twins aged from 3 to 11 years. Three scoring methods, namely the summed score, logistic regression, and decision tree, were employed to evaluate parent response accuracy of twin zygosity based on single nucleotide polymorphism (SNP) information. The results showed that all three methods achieved high level of accuracy ranging from 91 to 93 % which was comparable to the accuracy rates in previous Chinese twin studies. Correlation results also showed that the higher the parents' education level or the family income was, the more likely parents were able to tell correctly that their twins are identical or fraternal. The present findings confirmed the validity of using a three-item parent questionnaire to determine twin zygosity in a Chinese school-aged twin sample.

Genetic and Environmental Influences on Systemic Markers of Inflammation in Middle-Aged Male Twins

PubMed Central

Su, Shaoyong; Snieder, Harold; Miller, Andrew H.; Ritchie, James; Bremner, J. Douglas; Goldberg, Jack; Dai, Jun; Jones, Linda; Murrah, Nancy V.; Zhao, Jinying; Vaccarino, Viola

2008-01-01

Objectives The aims of this study were to determine the relative influence of genetic and environmental contributions to inflammatory biomarkers, and to what extent correlations among these markers are due to genetic or environmental factors. Methods We performed univariate and multivariate genetic analyses of four inflammatory markers: interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), C-reactive protein (CRP), and fibrinogen, in 166 (88 monozygotic and 78 dizygotic) middle-aged male twin pairs. Results The mean age (±SD) of the twins was 54 (±2.93) years. Heritability was substantial for CRP (0.61, 95% CI: 0.47–0.72) and moderate to fair for IL-6 (0.31, 0.13–0.46), sIL-6R (0.49, 0.30–0.76) and fibrinogen (0.52, 0.34–0.65). IL-6, CRP and fibrinogen showed significant correlations, but not with sIL-6R. Multivariate genetic analysis found that these correlations could be best explained by a common pathway model, where the common factor explained 27%, 73% and 25% of the variance of IL-6, CRP and fibrinogen, respectively. About 46% (95% CI: 21–64%) of the correlations among the three inflammatory markers could be explained by the genetic factors. After adjusting for covariates known to influence inflammation levels, heritability estimates were slightly decreased but the overall results remained similar. Conclusions A significant part of the variation in inflammatory marker levels is due to genetic influences. Furthermore, almost 50% of the shared variance among these biomarkers is due to a common genetic factor which likely plays a key role in the regulation of inflammation. PMID:18243214

Does marriage inhibit antisocial behavior?: An examination of selection vs causation via a longitudinal twin design.

PubMed

Burt, S Alexandra; Donnellan, M Brent; Humbad, Mikhila N; Hicks, Brian M; McGue, Matt; Iacono, William G

2010-12-01

Previous studies have indicated that marriage is negatively associated with male antisocial behavior. Although often interpreted as a causal association, marriage is not a random event. As such, the association may stem from selection processes, whereby men less inclined toward antisocial behavior are more likely to marry. To evaluate selection vs causation explanations of the association between marriage and desistence from antisocial behavior. Co-twin control analyses in a prospective twin study provided an analogue of the idealized counterfactual model of causation. The co-twin control design uses the unmarried co-twin of a married twin to estimate what the married twin would have looked like had he remained unmarried. Discordant monozygotic (MZ) twins are particularly informative because they share a common genotype and rearing environment. General community study. Two hundred eighty-nine male-male twin pairs (65.1% MZ) from the Minnesota Twin Family Study underwent assessment at 17, 20, 24, and 29 years of age. None of the participants were married at 17 years of age, and 2.6% were married at 20 years of age. By 29 years of age, 58.8% of the participants were or had been married. A tally of criterion C symptoms of DSM-III-R antisocial personality disorder, as assessed via structured clinical interview. Mean differences in antisocial behavior across marital status at age 29 years were present even at 17 and 20 years of age, suggesting a selection process. However, the within-pair effect of marriage was significant for MZ twins, such that the married twin engaged in less antisocial behavior following marriage than his unmarried co-twin. Results were equivalent to those in dizygotic twins and persisted when controlling for prior antisocial behavior. Results indicate an initial selection effect, whereby men with lower levels of antisocial behavior are more likely to marry. However, this tendency to refrain from antisocial behavior appears to be accentuated by the

Sex ratios provide evidence for monozygotic twinning in the ring-tailed lemur, Lemur catta.

PubMed

St Clair, John; Campbell-Palmer, Roisin; Lathe, Richard

2014-02-01

Monozygotic (MZ) twinning is generally considered to be rare in species other than human. We inspected sex ratios in European zoo-bred ring-tailed lemurs (Lemur catta), revealing a significant excess of same-sex twins. Of 94 pairs, 60 (64%) were either both males or both females (p = .004). Application of the Weinberg differential rule argues that 27% of all twins in this species are MZ pairs. In this protected species, where twinning is commonplace (~50% of newborns are twins), the probable existence of frequent MZ twinning has ramifications for breeding programs aimed to maximize genetic diversity, and suggests that twin studies in a species other than human could have potential as a medical research tool.

Transference and insight in psychotherapy with gay and bisexual male clients: the role of sexual orientation identity integration.

PubMed

Mohr, Jonathan J; Fuertes, Jairo N; Stracuzzi, Thomas I

2015-03-01

Clinical writing has suggested that the therapeutic process and relationship in work with lesbian, gay, and bisexual clients may be influenced by the extent to which clients have accepted their sexual orientation and developed a social network supportive of their sexual orientation, a construct we refer to as sexual orientation identity integration. The present cross-sectional study investigated this proposition by examining the identity integration ratings of 90 gay and bisexual male clients in relation to elements of treatment as rated by both the therapist (insight, negative transference, working alliance, session depth, and client improvement) and client (working alliance, session depth, and client improvement). Participants were male-male therapy dyads recruited from lesbian, gay, and bisexual-affirming practices. Client identity integration was negatively associated with transference, and positively associated with ratings of insight, alliance, depth, and improvement. Insight, but not transference, uniquely mediated the positive association between identity integration and most indicators of therapeutic quality. Results from an exploratory model suggested that transference may indirectly influence therapeutic quality by serving as a barrier to insight. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Tribute to dr louis keith: twin and physician extraordinaire/twin research reports: influences on asthma severity; chimerism revisited; DNA strand break repair/media reports: twins born apart; elevated twin frequencies; celebrity father of twins; conjoined twinning.

PubMed

Segal, Nancy L

2014-10-01

The International Society for Twin Studies has lost a valued friend and colleague. Dr Louis Keith, Emeritus Professor of Obstetrics and Gynecology at Northwestern University, in Chicago, passed away on Sunday, July 6, 2014. His life and work with twins will be acknowledged at the November 2014 International Twin Congress in Budapest, Hungary. Next, twin research reports on the severity of asthma symptoms, a case of chimerism, and factors affecting DNA breakage and repair mechanisms are reviewed. Media reports cover twins born apart, elevated twin frequencies, a celebrity father of twins, and a family's decision to keep conjoined twins together.

'Biracial'-Looking Twins: A New Twin Type?/Twin Research: Twins with Cystic Teratomas; Sleep Quality and Body Mass Index; Previable Membrane Rupture/Print and Online Reports: Twins Born to a Sister Surrogate; NASA Twin Study; African-Cosmopolitan Twin Fashion Inspirations; Triplet Hockey Stars.

PubMed

Segal, Nancy L

2017-06-01

Dizygotic (DZ) co-twins born to mothers and fathers from different racial or ethnic backgrounds often resemble one parent much more than the other. As such, these pairs comprise a unique subset of twins for investigating how others' responses to their different looks may affect their personalities and self-esteem. This article describes some of these twin pairs and some challenges of raising them, and suggests ways they may be used in research. Next, recent twin research on cystic teratomas, relations between sleep quality and body mass index, and previable membrane rupture is described. The final section concerns twins, twin studies, and related events in the media, namely: twins born to a sister surrogate, the NASA twin investigation, inspiring African-Cosmopolitan twins in fashion, and triplet Hockey Stars.

A bright triggered twin-photon source in the solid state

PubMed Central

Heindel, T.; Thoma, A.; von Helversen, M.; Schmidt, M.; Schlehahn, A.; Gschrey, M.; Schnauber, P.; Schulze, J. -H.; Strittmatter, A.; Beyer, J.; Rodt, S.; Carmele, A.; Knorr, A.; Reitzenstein, S.

2017-01-01

A non-classical light source emitting pairs of identical photons represents a versatile resource of interdisciplinary importance with applications in quantum optics and quantum biology. To date, photon twins have mostly been generated using parametric downconversion sources, relying on Poissonian number distributions, or atoms, exhibiting low emission rates. Here we propose and experimentally demonstrate the efficient, triggered generation of photon twins using the energy-degenerate biexciton–exciton radiative cascade of a single semiconductor quantum dot. Deterministically integrated within a microlens, this nanostructure emits highly correlated photon pairs, degenerate in energy and polarization, at a rate of up to (234±4) kHz. Furthermore, we verify a significant degree of photon indistinguishability and directly observe twin-photon emission by employing photon-number-resolving detectors, which enables the reconstruction of the emitted photon number distribution. Our work represents an important step towards the realization of efficient sources of twin-photon states on a fully scalable technology platform. PMID:28367950

A twin study of the effects of the Vietnam conflict on alcohol drinking patterns.

PubMed Central

Goldberg, J; Eisen, S A; True, W R; Henderson, W G

1990-01-01

This study examines the association between military service in Southeast Asia and alcohol drinking patterns in 2,169 male-male monozygotic twin pairs who both served on active military duty during the Vietnam era (1965-75). Data on alcohol drinking were collected in 1987 by mail and telephone interview. The alcohol drinking measures include three indicators of abstention (lifetime abstainer, lifetime non-regular drinker, and current abstainer) and two indicators of consumption (average daily ethanol consumption and high consumption). In unadjusted and co-twin adjusted analyses, neither service in Southeast Asia nor combat exposure was significantly associated with any measure of abstention. In the co-twin adjusted analysis, there was no association of Southeast Asia service and combat exposure with average daily ethanol consumption. After adjustment for co-twin effects, 4.0 percent of non-Southeast Asia veterans were high consumers compared to 6.7 percent of Southeast Asia veterans who served in high combat. We conclude that prior military service in a war zone has a relatively modest long-term effect on the alcohol drinking patterns of male veterans. PMID:2327534

A New Look at Genetic and Environmental Architecture on Lipids Using Non-Normal Structural Equation Modeling in Male Twins: The NHLBI Twin Study.

PubMed

Wu, Sheng-Hui; Ozaki, Koken; Reed, Terry; Krasnow, Ruth E; Dai, Jun

2017-07-01

This study examined genetic and environmental influences on the lipid concentrations of 1028 male twins using the novel univariate non-normal structural equation modeling (nnSEM) ADCE and ACE models. In the best fitting nnSEM ADCE model that was also better than the nnSEM ACE model, additive genetic factors (A) explained 4%, dominant genetic factors (D) explained 17%, and common (C) and unique (E) environmental factors explained 47% and 33% of the total variance of high-density lipoprotein cholesterol (HDL-C). The percentage of variation explained for other lipids was 0% (A), 30% (D), 34% (C) and 37% (E) for low-density lipoprotein cholesterol (LDL-C); 30, 0, 31 and 39% for total cholesterol; and 0, 31, 12 and 57% for triglycerides. It was concluded that additive and dominant genetic factors simultaneously affected HDL-C concentrations but not other lipids. Common and unique environmental factors influenced concentrations of all lipids.

Electrical resistivity of ultrafine-grained copper with nanoscale growth twins

NASA Astrophysics Data System (ADS)

Chen, X. H.; Lu, L.; Lu, K.

2007-10-01

We have investigated electrical resistivities of high-purity ultrafine-grained Cu containing different concentrations of nanoscale growth twins, but having identical grain size. The samples were synthesized by pulsed electrodeposition, wherein the density of twins was varied systematically by adjusting the processing parameters. The electrical resistivity of the Cu specimen with a twin spacing of 15nm at room temperature (RT) is 1.75μΩcm (the conductivity is about 97% IACS), which is comparable to that of coarse-grained (CG) pure Cu specimen. A reduction in twin density for the same grain size (with twin lamellar spacings of 35 and 90nm, respectively) results in an increment in electrical resistivity from 1.75to2.12μΩcm. However, the temperature coefficient of resistivity at RT for these Cu specimens is insensitive to the twin spacing and shows a consistent value of ˜3.78×10-3/K, which is slightly smaller than that of CG Cu (3.98×10-3/K). The increased electrical resistivities of the Cu samples were ascribed dominantly to the intrinsic grain boundary (GB) scattering, while the GB defects and GB energy would decrease with increasing twin density. Transmission electron microscope observations revealed the GB configuration difference from the Cu samples with various twin densities. Plastic deformation would induce an apparent increase in the resistivity. The higher of the twin density, the higher increment of RT resistivity was detected in the Cu specimens subjected to 40% rolling strain. Both the deviated twin boundaries and strained GBs may give rise to an increase in the resistivity.

[Adult twins].

PubMed

Charlemaine, Christiane

2006-12-31

This paper explores the deep roots of closeness that twins share in their youngest age and their effect on their destiny at the adult age. Psychologists believe the bond between twins begins in utero and develops throughout the twins' lives. The four patterns of twinship described show that the twin bond is determined by the quality of parenting that twins receive in their infancy and early childhood. Common problems of adult twins bring about difficulties to adapt in a non-twin world. The nature versus nurture controversy has taken on new life focusing on inter-twin differences and the importance of parent-child interaction as fundamental to the growth and development of personality.

Risk of Sex-Specific Cancers in Opposite-Sex and Same-Sex Twins in Denmark and Sweden

PubMed Central

Ahrenfeldt, Linda J.; Skytthe, Axel; Möller, Sören; Czene, Kamila; Adami, Hans-Olov; Mucci, Lorelei A.; Kaprio, Jaakko; Petersen, Inge; Christensen, Kaare; Lindahl-Jacobsen, Rune

2016-01-01

Background Increasing evidence shows that some cancers originate in utero. It is hypothesized that elevated exposure to some steroid hormones might increase cancer risk and that hormone transfer between twin fetuses could result in different prenatal exposure to testosterone. Methods This large-scale prospective twin study compared opposite-sex (OS) and same-sex (SS) twins to test the impact of intrauterine exposures on cancer risk. On the basis of the Danish and Swedish twin and cancer registries, we calculated incidence rate ratios for OS and SS twins, whereas standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated for OS/SS twins compared with the general population. Results Atotal of 18,001 cancers were identified during 1943–2009. No significant differences were observed between OS and SS twins, neither for the sex-specific cancers nor for cancer at all sites. All-cause cancer was slightly reduced for OS and SS twins compared with the general population, significant for OS males (SIR, 0.95; 95% CI, 0.92–0.98) and for SS males and females (SIR, 0.97; 95% CI, 0.94–0.99). Conclusions Our data suggest that having a male co-twin—which may entail higher exposure to prenatal testosterone—does not increase the risk of sex-specific cancers in OS females. Furthermore, the study supports that twinning per se is not a risk factor of cancer. Impact Findings are reassuring, as they fail to provide evidence for the hypothesis that endocrine or other difference in the in utero milieu affects the risk of sex-specific cancers. PMID:26282631

Transgender identity development as represented by a group of female-to-male transgendered adults.

PubMed

Morgan, Sarah W; Stevens, Patricia E

2008-06-01

This article represents work done in the discipline of nursing to raise awareness about the lives and experiences of transgendered persons, who receive little coverage in our nursing textbooks, professional journals, or student clinical experiences. The findings presented here are from a larger qualitative examination of the lives and experiences of a group of 11 transgendered adults that examined four broad areas: transgender identity recognition, acknowledgement, and development; bodily experiences; relationships with others; and health care experiences. The focus of this article is the relevant findings related to four participants in the study who identified as female-to-male (FTM), meaning they were born female-bodied, but identify as male. The highlight here is on the recognition, acknowledgement, and development of transgender identity. Our intention is to expose uninformed people to first-hand accounts by FTM transgendered persons about their life trajectories, particularly during childhood, adolescence, and the early adult years.

Dermacentor (Indocentor) taiwanensis (Acari: Ixodoidea: Ixodidae): Identity of Male and Female

DTIC Science & Technology

1986-03-31

ORGANIZATION Naval Medical Research and Development Command 8b OFFICE SYMBOL (if appfoab««) NMROC 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER...taiwanensis (Acari: Ixodoldea: Ixodidae) Identity of Male and Female — (UNCLASSIFIED) ~ — ~~ 12 PERSONAL ALITHOR(S) Wasser , Hilda Y. and...Cairo. EOVP»! 22c OFFICE SYMBOL R.P.D. DO FORM 1473,84 MAR ii A?R edition may be used until ««nausted All other editions are obsolete SECURITY CLASSIFICATION OF THIS PAGE UNCLASSIFIED

Janiceps conjoined twins with extreme asymmetry: case report with complete autopsy and histopathologic findings.

PubMed

Kastenbaum, Hannah A; McPherson, Elizabeth W; Murdoch, Geoffrey H; Ozolek, John A

2009-01-01

Conjoined twinning is a rare form of twinning, in which 2 bodies are attached, and is classified according to the anatomic place of attachment. An extremely rare form of conjoined twinning is janiceps conjoined twinning, in which 2 faces are attached but oriented in opposite directions. In this report, we present an unusual and difficult-to-classify case of conjoined male twins with partial duplication of craniofacial, upper oropharyngeal, and cardiac organs. We believe this to be one of the few reported cases of janiceps asymmetrus. We describe in detail the gross and microscopic pathology and offer some insights into the possible embryogenesis and distinction from the other rare form of conjoined twinning with facial duplication, diprosopus.

Diagnosis of twin-to-twin transfusion syndrome, selective fetal growth restriction, twin anaemia-polycythaemia sequence, and twin reversed arterial perfusion sequence.

PubMed

Sueters, Marieke; Oepkes, Dick

2014-02-01

Monochorionic twin pregnancies are well known to be at risk for a variety of severe complications, a true challenge for the maternal-fetal medicine specialist. With current standards of care, monochorionicity should be established in the first trimester. Subsequently, frequent monitoring using the appropriate diagnostic tools, and in-depth knowledge about the pathophysiology of all possible clinical presentations of monochorionic twin abnormalities, should lead to timely recognition, and appropriate management. Virtually all unique diseases found in monochorionic twins are directly related to placental angio-architecture. This, however, cannot be established reliably before birth. The clinician needs to be aware of the definitions and symptoms of twin-to twin transfusion syndrome, selective fetal growth restriction, twin anaemia-polycythaemia sequence, and twin reversed arterial perfusion sequence, to be able to recognise each disease and take the required action. In this chapter, we address current standards on correct and timely diagnoses of severe complications of monochorionic twin pregnancies. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Placenta in Twin-to-Twin Transfusion Syndrome and Twin Anemia Polycythemia Sequence.

PubMed

Couck, Isabel; Lewi, Liesbeth

2016-06-01

Twin-to-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS) are complications unique to monochorionic twin pregnancies and their shared circulation. Both are the result of the transfusion imbalance in the intertwin circulation. TTTS is characterized by an amniotic fluid discordance, whereas in TAPS, there is a severe discordance in hemoglobin levels. The article gives an overview of the typical features of TTTS and TAPS placentas.

[MALE, FEMALE, NEUTRUM. SEXUAL IDENTITY, UNCERTAIN SEX AND BIOLOGY].

PubMed

Famularo, Simone

2014-01-01

For almost 2000 years, human beings have been discussing about gender. New scientific evidences give interesting new points of view, partially subverting the normal dichotomy described by the "two-gender" theory. In this article, we are going to critically review the history of the approach towards people born with a Sexual-Differentiation-Disorder, passing through the analysis of the Italian National Ethics Committee's opinion, describing the modern scientific evidences on the gender-identity development, furthermore ruling out the new approach borned from the femminist philosophies, and the new biogiuridical experiments borned in Australia and Germany. Would it be possible a world where a person could be more then a male or a female?

The Impact of Racial Identity and Consciousness Development of African American Male Academic Achievement: Implications for Counseling

ERIC Educational Resources Information Center

Whiteside, Dora

2007-01-01

The purpose of this study was to examine the effect of racial identity/consciousness development on the academic achievement of African American male college freshmen. In the late 1900s Black identity models were developed to help African Americans grasp hold of who they were, as they lived in the residues of the peculiar institution of slavery.…

Antenatal management of twin-twin transfusion syndrome and twin anemia-polycythemia sequence.

PubMed

Slaghekke, Femke; Zhao, Depeng P; Middeldorp, Johanna M; Klumper, Frans J; Haak, Monique C; Oepkes, Dick; Lopriore, Enrico

2016-08-01

Twin-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS) are severe complications in monochorionic twin pregnancies associated with high mortality and morbidity risk if left untreated. Both diseases result from imbalanced inter-twin blood transfusion through placental vascular anastomoses. This review focuses on the differences in antenatal management between TTTS and TAPS. Expert commentary: The optimal management for TTTS is fetoscopic laser coagulation of the vascular anastomoses, preferably using the Solomon technique in which the whole vascular equator is coagulated. The Solomon technique is associated with a reduction of residual anastomosis and a reduction in post-operative complications. The optimal management for TAPS is not clear and includes expectant management, intra-uterine transfusion with or without partial exchange transfusion and fetoscopic laser surgery.

South Dakota Adolescent Males' Perceptions regarding Influences on Gender Identity and Role Acquisition

ERIC Educational Resources Information Center

Brown, Nedd I.

2009-01-01

The purpose of this study was to explore the perceptions of a selected group of rural high school male students regarding their attitudes about the influences they perceive in their lives that have had an impact on their gender identity. This study surveyed the perceptions of a group of high school students from Dell Rapids High School in rural…

Esophageal atresia with tracheoesophageal fistula in both members of monozygotic twins.

PubMed

Ohno, Koichi; Nakamura, Tetsuro; Azuma, Takashi; Yoshida, Tatsuyuki; Yamada, Hiroto; Hayashi, Hiroaki; Masahata, Kazunori

2008-10-01

A 29-year-old healthy woman bore monozygotic male twins at 37 weeks of gestation by cesarean section. They weighed 2,350 and 2,140 g, respectively. Twin B was found to have a ventricular septal defect. They were diagnosed with esophageal atresia (EA) with tracheoesophageal fistula and underwent primary end-to-end esophageal anastomosis at the age of 1 day. Their postoperative courses were uneventful. Although the incidence of EA is higher in twins than in singletons, usually, EA affects only one of twins. There have been only 20 pairs of twins concordant for the EA anomaly. There is no distinct difference between sporadic EA and EA in both twins (EABT) with regard to sexuality, classification, and incidence of associated anomalies. The zygosity of EABT consisted of 15 monozygosities (83.3%) and 3 dizygosities (16.7%). An overwhelmingly higher incidence of monozygosity than that of dizygosity in EABT suggests that genetic factors must play a considerable role in the embryology in EABT cases.

148. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

148. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER DAM; HEADGATES AT INLET, SOUTHWEST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

98. SHOESTRING, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

98. SHOESTRING, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST OF MURTAUGH, IDAHO; PROFILE VIEW, SOUTH. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

147. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

147. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER, IDAHO; VIEW OF MAIN HEADGATES, EAST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

97. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

97. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST OF MURTAUGH, IDAHO; OVERALL WEST VIEW FROM CANAL SIDE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

149. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

149. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER DAM; CLOSE-UP OF MAIN CANAL GATES, SOUTH VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

141. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

141. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER, IDAHO; CLOSE-UP OF MAIN HEADGATES, RADIAL GATES INSIDE, SOUTHEAST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

137. TWIN FALLS SOUTH SIDE MAIN CANAL DIVERSION HEADGATES, TWIN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

137. TWIN FALLS SOUTH SIDE MAIN CANAL DIVERSION HEADGATES, TWIN FALLS COUNTY, MILNER, IDAHO; OVERALL VIEW OF MAIN HEADGATES, DAM IN BACKGROUND. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

99. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

99. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST OF MURTAUGH, IDAHO; CLOSE-UP OF OUTLET SIDE OF GATES, SOUTH VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

Genetic Factors That Increase Male Facial Masculinity Decrease Facial Attractiveness of Female Relatives

PubMed Central

Lee, Anthony J.; Mitchem, Dorian G.; Wright, Margaret J.; Martin, Nicholas G.; Keller, Matthew C.; Zietsch, Brendan P.

2014-01-01

For women, choosing a facially masculine man as a mate is thought to confer genetic benefits to offspring. Crucial assumptions of this hypothesis have not been adequately tested. It has been assumed that variation in facial masculinity is due to genetic variation and that genetic factors that increase male facial masculinity do not increase facial masculinity in female relatives. We objectively quantified the facial masculinity in photos of identical (n = 411) and nonidentical (n = 782) twins and their siblings (n = 106). Using biometrical modeling, we found that much of the variation in male and female facial masculinity is genetic. However, we also found that masculinity of male faces is unrelated to their attractiveness and that facially masculine men tend to have facially masculine, less-attractive sisters. These findings challenge the idea that facially masculine men provide net genetic benefits to offspring and call into question this popular theoretical framework. PMID:24379153

Genetic factors that increase male facial masculinity decrease facial attractiveness of female relatives.

PubMed

Lee, Anthony J; Mitchem, Dorian G; Wright, Margaret J; Martin, Nicholas G; Keller, Matthew C; Zietsch, Brendan P

2014-02-01

For women, choosing a facially masculine man as a mate is thought to confer genetic benefits to offspring. Crucial assumptions of this hypothesis have not been adequately tested. It has been assumed that variation in facial masculinity is due to genetic variation and that genetic factors that increase male facial masculinity do not increase facial masculinity in female relatives. We objectively quantified the facial masculinity in photos of identical (n = 411) and nonidentical (n = 782) twins and their siblings (n = 106). Using biometrical modeling, we found that much of the variation in male and female facial masculinity is genetic. However, we also found that masculinity of male faces is unrelated to their attractiveness and that facially masculine men tend to have facially masculine, less-attractive sisters. These findings challenge the idea that facially masculine men provide net genetic benefits to offspring and call into question this popular theoretical framework.

Young Sexual Minority Males in the United States: Sociodemographic Characteristics And Sexual Attraction, Identity and Behavior.

PubMed

Fasula, Amy M; Oraka, Emeka; Jeffries, William L; Carry, Monique; Bañez Ocfemia, M Cheryl; Balaji, Alexandra B; Rose, Charles E; Jayne, Paula E

2016-03-01

HIV incidence is increasing among 13-24-year-old U.S. men who have sex with men, yet limited research is available to guide HIV prevention efforts for this population. National Survey of Family Growth data collected in 2002, in 2006-2010 and in 2011-2013 from 8,068 males aged 15-24 were analyzed to describe the population of U.S. young sexual minority males (i.e., males reporting same-sex attraction, identity or behavior). Correlates of sexual minority classification were assessed in logistic regression models. An estimated 10% of young males, representing a population of 2.1 million, were sexual minorities. Males had an elevated likelihood of being sexual minorities if they were aged 18-19 or 20-24, rather than 15-17 (prevalence ratio, 1.7 for each); belonged to nonblack, non-Hispanic racial or ethnic minority groups (1.6); had no religious affiliation, rather than considering religion very important (1.9); or lived below the federal poverty level (1.3). They had a reduced likelihood of being sexual minorities if they lived in metropolitan areas outside of central cities (0.7). Among young sexual minority males, 44% were 15-19 years old, 29% were poor and 59% resided outside central cities. Forty-seven percent had engaged in same-sex behavior. Of those with data on all measured dimensions of sexuality, 24% reported same-sex attraction, identity and behavior; 22% considered themselves heterosexual, yet had had a male sex partner. Future investigations can further explore subpopulations of young sexual minority males and assess sexual trajectories, resilience and HIV risk. Copyright © 2016 by the Guttmacher Institute.

Art for twins: Yorùbá artists and their statues/twin research studies: twins' education and conceptions; diurnal preference; inherited eye diseases; ultrasound counseling when twins are conjoined/popular twin reports: twin sisters (the film); rare pregnancy; diet test; French twins reared apart and reunited.

PubMed

Segal, Nancy L

2014-06-01

The Yorùbá of Nigeria are well known for their high twinning rate and the statues they create to commemorate deceased twins. An impressive collection of this artwork was displayed at the University of California's Fowler Museum in Los Angeles between October 13, 2013 and March 2, 2014. An overview of this exhibit is provided. Next, twin research on maternal education and conception, diurnal preference, inherited eye diseases, and ultrasound counseling for couples with conjoined twins are briefly summarized. This article concludes with a discussion of media-based items related to twins. The topics include an award-winning twin film, a rare pregnancy, a diet test, and the separation and chance reunion of monozygotic female twins.

Ecosensitivity and genetic polymorphism of somatic traits in the perinatal development of twins.

PubMed

Waszak, Małgorzata; Cieślik, Krystyna; Skrzypczak-Zielińska, Marzena; Szalata, Marlena; Wielgus, Karolina; Kempiak, Joanna; Bręborowicz, Grzegorz; Słomski, Ryszard

2016-04-01

In view of criticism regarding the usefulness of heritability coefficients, the aim of this study was to analyze separately the information on genetic and environmental variability. Such an approach, based on the normalization of trait's variability for its value, is determined by the coefficients of genetic polymorphism (Pg) and ecosensitivity (De). The studied material included 1263 twin pairs of both sexes (among them 424 pairs of monozygotic twins and 839 pairs of dizygotic twins) born between the 22nd and 41st week of gestation. Variability of six somatic traits was analyzed. The zygosity of same-sex twins was determined based on the polymorphism of DNA from lymphocytes of the umbilical cord blood, obtained at birth. The coefficients of genetic polymorphism and ecosensitivity for analyzed traits of male and female twins born at various months of gestation were calculated. Our study revealed that a contribution of the genetic component predominated over that of the environmental component in determining the phenotypic variability of somatic traits of newborns from twin pregnancies. The genetically determined phenotypic variability in male twins was greater than in the females. The genetic polymorphism and ecosensitivity of somatic traits were relatively stable during the period of fetal ontogeny analyzed in this study. Only in the case of body weight, a slight increase in the genetic contribution of polygenes to the phenotypic variance could be observed with gestational age, along with a slight decrease in the influence of environmental factors. Copyright © 2015 Elsevier GmbH. All rights reserved.

Prenatal and Perinatal Risk Factors in a Twin Study of Autism Spectrum Disorders

PubMed Central

Froehlich-Santino, Wendy; Tobon, Amalia Londono; Cleveland, Sue; Torres, Andrea; Phillips, Jennifer; Cohen, Brianne; Torigoe, Tiffany; Miller, Janet; Fedele, Angie; Collins, Jack; Smith, Karen; Lotspeich, Linda; Croen, Lisa A.; Ozonoff, Sally; Lajonchere, Clara; Grether, Judith K.; O’Hara, Ruth; Hallmayer, Joachim

2014-01-01

Introduction Multiple studies associate prenatal and perinatal complications with increased risks for autism spectrum disorders (ASDs). The objectives of this study were to utilize a twin study design to 1) Investigate whether shared gestational and perinatal factors increase concordance for ASDs in twins, 2) Determine whether individual neonatal factors are associated with the presence of ASDs in twins, and 3) Explore whether associated factors may influence males and females differently. Methods Data from medical records and parent response questionnaires from 194 twin pairs, in which at least one twin had an ASD, were analyzed. Results Shared factors including parental age, prenatal use of medications, uterine bleeding, and prematurity did not increase concordance risks for ASDs in twins. Among the individual factors, respiratory distress demonstrated the strongest association with increased risk for ASDs in the group as a whole (OR 2.11, 95% CI 1.27–3.51). Furthermore, respiratory distress (OR 2.29, 95% CI 1.12–4.67) and other markers of hypoxia (OR 1.99, 95% CI 1.04–3.80) were associated with increased risks for ASDs in males, while jaundice was associated with an increased risk for ASDs in females (OR 2.94, 95% CI 1.28–6.74). Conclusions Perinatal factors associated with respiratory distress and other markers of hypoxia appear to increase risk for autism in a subgroup of twins. Future studies examining potential gender differences and additional prenatal, perinatal and postnatal environmental factors are required for elucidating the etiology of ASDs and suggesting new methods for treatment and prevention. PMID:24726638

Psychiatric outcomes of bullying victimization: a study of discordant monozygotic twins.

PubMed

Silberg, J L; Copeland, W; Linker, J; Moore, A A; Roberson-Nay, R; York, T P

2016-07-01

Bullying victimization in childhood is associated with a broad array of serious mental health disturbances, including anxiety, depression, and suicidal ideation and behavior. The key goal of this study was to evaluate whether bullying victimization is a true environmental risk factor for psychiatric disturbance using data from 145 bully-discordant monozygotic (MZ) juvenile twin pairs from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) and their follow-up into young adulthood. Since MZ twins share an identical genotype and familial environment, a higher rate of psychiatric disturbance in a bullied MZ twin compared to their non-bullied MZ co-twin would be evidence of an environmental impact of bullying victimization. Environmental correlations between being bullied and the different psychiatric traits were estimated by fitting structural equation models to the full sample of MZ and DZ twins (N = 2824). Environmental associations were further explored using the longitudinal data on the bullying-discordant MZ twins. Being bullied was associated with a wide range of psychiatric disorders in both children and young adults. The analysis of data on the MZ-discordant twins supports a genuine environmental impact of bullying victimization on childhood social anxiety [odds ratio (OR) 1.7], separation anxiety (OR 1.9), and young adult suicidal ideation (OR 1.3). There was a shared genetic influence on social anxiety and bullying victimization, consistent with social anxiety being both an antecedent and consequence of being bullied. Bullying victimization in childhood is a significant environmental trauma and should be included in any mental health assessment of children and young adults.

Obsessive-compulsive symptoms and related sex differences in brain structure: an MRI study in Dutch twins.

PubMed

den Braber, Anouk; de Geus, Eco J C; Boomsma, Dorret I; van 't Ent, Dennis

2013-04-01

Neuroimaging studies have indicated abnormalities in cortico-striato-thalamo-cortical circuits in obsessive-compulsive disorder patients, but results have not been consistent. Since there are significant sex differences in human brain anatomy and obsessive-compulsive symptomatology and its developmental trajectories tend to be distinct in males and females, we investigated whether sex is a potential source of heterogeneity in neuroimaging studies on obsessive-compulsive symptoms. We selected male and female twin pairs who were concordant for scoring either high or low for obsessive-compulsive symptoms and a group of discordant pairs where one twin scored high and the co-twin scored low. The design included 24 opposite-sex twin pairs. Magnetic resonance imaging scans of 31 males scoring high for obsessive-compulsive symptoms, 41 low-scoring males, 58 high-scoring females, and 73 low-scoring females were analyzed and the interaction of obsessive-compulsive symptoms by sex on gray matter volume was assessed using voxel-based morphometry. An obsessive-compulsive symptom by sex interaction was observed for the left middle temporal gyrus, the right middle temporal gyrus, and the right precuneus. These interactions acted to reduce or hide a main effect in our study and illustrate the importance of taking sex into account when investigating the neurobiology of obsessive-compulsive symptoms.

Pathology of twin placentas with special attention to monochorionic twin placentas.

PubMed

Nikkels, P G J; Hack, K E A; van Gemert, M J C

2008-12-01

The risk of perinatal morbidity and mortality in twins is 3-7 times higher than in singletons. In comparison to dichorionic twins, monochorionic twins are at increased risk for perinatal mortality and serious morbidity. In both type of twins growth discordance can occur. Discordant growth of dichorionic twins could be due to differences in placental mass or differences in placental parenchymal lesions, whereas birth weight discordancy in monochorionic twins is caused by placental vascular anastomoses. In this review the different types of complications (acardiac twins, acute and chronic twin-twin transfusion syndrome) due to different combinations of vascular anastomoses are discussed in relation to a computer model developed to gain more insight into the development of the twin-twin transfusion syndrome. The angioarchitecture of 395 monochorionic twin placentas was studied. Mortality was highest in the absence of an arterio-arterial anastomosis (42%) and lowest in the presence of an arterio-arterial anastomosis (15%). If mortality occurred, pregnancies with double mortality usually had an arterio-arterial anastomosis. If pregnancies were complicated by one death, a veno-venous anastomosis is more likely to be present. In conclusion, monochorionic twin pregnancies are a high risk pregnancy with a high chance of both mortality and morbidity; placental characteristics are a major contributor to adverse outcome in these pregnancies.

PATERNAL ALCOHOLISM AND OFFSPRING ADHD PROBLEMS: A CHILDREN OF TWINS DESIGN

PubMed Central

Knopik, Valerie S.; Jacob, Theodore; Haber, Jon Randolph; Swenson, Lance P.; Howell, Donelle N.

2013-01-01

Objective A recent Children-of-Female-Twin design suggests that the association between maternal alcohol use disorder and offspring ADHD is due to a combination of genetic and environmental factors, such as prenatal nicotine exposure. We present here a complementary analysis using a Children-of-Male-Twin design examining the association between paternal alcoholism and offspring attention deficit hyperactivity problems (ADHP). Methods Children-of-twins design: offspring were classified into 4 groups of varying genetic and environmental risk based on father and co-twin’s alcohol dependence status. Results Univariate results are suggestive of a genetic association between paternal alcohol dependence and broadly defined offspring ADHP. Specifically, offspring of male twins with a history of DSM-III-R alcohol dependence, as well as offspring of non-alcohol dependent monozygotic twins whose cotwin was alcohol dependent, were significantly more likely to exhibit ADHP than control offspring. However, multivariate models show maternal variables independently predicting increased risk for offspring ADHP and significantly decreased support for a genetic mechanism of parent-to-child transmission. Conclusions In support of earlier work, maternal variables (i.e., maternal ADHD and prenatal exposure) were strongly associated with child ADHP; however, the role of paternal alcohol dependence influences was not definitive. While genetic transmission may be important, the association between paternal alcohol dependence and child ADHP is more likely to be indirect and a result of several pathways. PMID:19210180

Differences in the Expression of TLR-2, NOD2, and NF-κB in Placenta Between Twins.

PubMed

Szylberg, Łukasz; Bodnar, Magdalena; Lebioda, Anna; Krepska, Patrycja; Kowalewski, Adam; Bręborowicz, Grzegorz; Marszałek, Andrzej

2018-05-23

Dizygotic twins share the same type of genetic relationship as non-twin siblings. Whereas monozygotic (MZ) twins are considered to have identical genetic material, they still differ. There is a number of reasons for early MZ twin discordance, including differences in the in utero environment, stochasticity, genetic mosaicism, and epigenetic factors. During gestation, the efficient innate immune system is of utmost importance. Our study was based on immunohistochemical evaluation of the differences in innate immune protein expression (TLR-2, NOD2, and NF-κB) in the 95 placentas between twins. Our study revealed statistical significant differences between diamniotic-dichorionic and monoamniotic-dichorionic twins. Monoamniotic-monochorionic twins exhibited no significant differences in protein expressions. To identify epigenetic factors causing the differences between twins, we made a series of comparisons with clinical data. The study revealed more cases with infections, miscarriages, in vitro fertilization, and premature rupture of membranes within the group with higher differences level of NF-κB, NOD2 and TLR-2 between twins. In case of twin-to-twin transfusion syndrome, there were no significant differences in innate immune protein expressions between twins. These results show that dissimilar genetic material and separate in utero environment promote discordance in innate immune protein expressions between twins. Moreover, additional blood flow between twins may be favorable in life-threatening conditions ensuring similar microenvironment.

A Twin Study on Perceived Stress, Depressive Symptoms, and Marriage.

PubMed

Beam, Christopher R; Dinescu, Diana; Emery, Robert; Turkheimer, Eric

2017-03-01

Marriage is associated with reductions in both perceived stress and depressive symptoms, two constructs found to be influenced by common genetic effects. A study of sibling twins was used to test whether marriage decreases the proportion of variance in depressive symptoms accounted for by genetic and environmental effects underlying perceived stress. The sample consisted of 1,612 male and female twin pairs from the University of Washington Twin Registry. The stress-buffering role of marriage was tested relative to two unmarried groups: the never married and the divorced. Multivariate twin models showed that marriage reduced genetic effects of perceived stress on depressive symptoms but did not reduce environmental effects. The findings suggest a potential marital trade-off for women: access to a spouse may decrease genetic effects of perceived stress on depressive symptoms, although marital and family demands may increase environmental effects of perceived stress on depressive symptoms.

A Twin Study on Perceived Stress, Depressive Symptoms, and Marriage

PubMed Central

Beam, Christopher R.; Dinescu, Diana; Emery, Robert E.; Turkheimer, Eric

2017-01-01

Marriage is associated with reductions in both perceived stress and depressive symptoms, two constructs found to be influenced by common genetic effects. A study of sibling twins was used to test whether marriage decreases the proportion of variance in depressive symptoms accounted for by genetic and environmental effects underlying perceived stress. The sample consisted of 1,612 male and female twin pairs from the University of Washington Twin Registry. The stress-buffering role of marriage was tested relative to two unmarried groups: the never married and the divorced. Multivariate twin models showed that marriage reduced genetic effects of perceived stress on depressive symptoms, but did not reduce environmental effects. The findings suggest a potential marital trade-off for women: Access to a spouse may decrease genetic effects of perceived stress on depressive symptoms, although marital and family demands may increase environmental effects of perceived stress on depressive symptoms. PMID:28661771

Habitual dietary sodium intake is inversely associated with coronary flow reserve in middle-aged male twins.

PubMed

Eufinger, Silvia C; Votaw, John; Faber, Tracy; Ziegler, Thomas R; Goldberg, Jack; Bremner, J Douglas; Vaccarino, Viola

2012-03-01

Evidence links dietary sodium to hypertension and cardiovascular disease (CVD), but investigation of its influence on cardiovascular function is limited. We examined the relation between habitual dietary sodium and coronary flow reserve (CFR), which is a measure of overall coronary vasodilator capacity and microvascular function. We hypothesized that increased sodium consumption is associated with lower CFR. Habitual daily sodium intake for the previous 12 mo was measured in 286 male middle-aged twins (133 monozygotic and dizygotic pairs and 20 unpaired twins) by using the Willett food-frequency questionnaire. CFR was measured by positron emission tomography [N(13)]-ammonia, with quantitation of myocardial blood flow at rest and after adenosine stress. Mixed-effects regression analysis was used to assess the association between dietary sodium and CFR. An increase in dietary sodium of 1000 mg/d was associated with a 10.0% lower CFR (95% CI: -17.0%, -2.5%) after adjustment for demographic, lifestyle, nutritional, and CVD risk factors (P = 0.01). Across quintiles of sodium consumption, dietary sodium was inversely associated with CFR (P-trend = 0.03), with the top quintile (>1456 mg/d) having a 20% lower CFR than the bottom quintile (<732 mg /d). This association also persisted within pairs: a 1000-mg/d difference in dietary sodium between brothers was associated with a 10.3% difference in CFR after adjustment for potential confounders (P = 0.02). Habitual dietary sodium is inversely associated with CFR independent of CVD risk factors and shared familial and genetic factors. Our study suggests a potential novel mechanism for the adverse effects of dietary sodium on the cardiovascular system. This trial was registered at clinicaltrials.gov as NCT00017836.

The Twins Study: NASA's First Foray into 21st Century Omics Research

NASA Technical Reports Server (NTRS)

Kundrot, C. E.; Shelhamer, M.; Scott, G. B. I.

2015-01-01

The full array of 21st century omics-based research methods should be intelligently employed to reduce the health and performance risks that astronauts will be exposed to during exploration missions beyond low Earth Orbit. In March of 2015, US Astronaut Scott Kelly will launch to the International Space Station for a one year mission while his twin brother, Mark Kelly, a retired US Astronaut, remains on the ground. This situation presents an extremely rare flight opportunity to perform an integrated omics-based demonstration pilot study involving identical twin astronauts. A group of 10 principal investigators has been competitively selected, funded, and teamed together to form the Twins Study. A very broad range of biological function are being examined including the genome, epigenome, transcriptome, proteome, metabolome, gut microbiome, immunological response to vaccinations, indicators of atherosclerosis, physiological fluid shifts, and cognition. The plans for the Twins Study and an overview of initial results will be described as well as the technological and ethical issues raised for such spaceflight studies. An anticipated outcome of the Twins Study is that it will place NASA on a trajectory of using omics-based information to develop precision countermeasures for individual astronauts.

Genetic and Environmental Etiologies of Reading Difficulties: DeFries-Fulker Analysis of Reading Performance Data from Twin Pairs and Their Non-Twin Siblings

ERIC Educational Resources Information Center

Astrom, Raven L.; Wadsworth, Sally J.; Olson, Richard K.; Willcutt, Erik G.; DeFries, John C.

2012-01-01

Reading performance data from 254 pairs of identical (MZ) and 420 pairs of fraternal (DZ) twins, 8.0 to 20.0 years of age, were subjected to multiple regression analyses. An extension of the DeFries-Fulker (DF) analysis (DeFries & Fulker, 1985, 1988) that facilitated inclusion of data from 303 of their nontwin siblings was employed. In addition to…

Environmental factors selectively impact co-occurrence of problem/pathological gambling with specific drug-use disorders in male twins.

PubMed

Xian, Hong; Giddens, Justine L; Scherrer, Jeffrey F; Eisen, Seth A; Potenza, Marc N

2014-04-01

Multiple forms of drug abuse/dependence frequently co-occur with problem/pathological gambling (PPG). The current study examines the extent to which genetic and environmental factors contribute to their co-occurrence. Bivariate models investigated the magnitude and correlation of genetic and environmental contributions to problem/pathological gambling and its co-occurrence with nicotine dependence, cannabis abuse/dependence and stimulant abuse/dependence. Computer-assisted telephone interviews in the community. Participants were 7869 male twins in the Vietnam Era Twin Registry, a USA-based national twin registry. Life-time DSM-III-R diagnoses for problem/pathological gambling, nicotine dependence, cannabis abuse/dependence and stimulant abuse/dependence were determined using the Diagnostic Interview Schedule. All drug-use disorders displayed additive genetic and non-shared environmental contributions, with cannabis abuse/dependence also displaying shared environmental contributions. Both genetic [genetic correlation rA  = 0.22; 95% confidence interval (CI) = 0.10-0.34] and non-shared environmental components (environmental correlation rE  = 0.24; 95% CI = 0.10-0.37) contributed to the co-occurrence of problem/pathological gambling and nicotine dependence. This pattern was shared by cannabis abuse/dependence (rA  = 0.32; 95% CI = 0.05-1.0; rE  = 0.36; 95% CI = 0.16-0.55) but not stimulant abuse/dependence (SAD), which showed only genetic contributions to the co-occurrence with problem/pathological gambling (rA  = 0.58; 95% CI = 0.45-0.73). Strong links between gambling and stimulant-use disorders may relate to the neurochemical properties of stimulants or the illicit nature of using 'hard' drugs such as cocaine. The greater contribution of environmental factors to the co-occurrence between problem/pathological gambling and 'softer' forms of drug abuse/dependence (cannabis, tobacco) suggest that environmental interventions

Psychiatric outcomes of bullying victimization: A study of discordant monozygotic twins

PubMed Central

Silberg, Judy L.; Copeland, William; Linker, Julie; Moore, Ashlee A.; Roberson-Nay, Roxann; York, Timothy P.

2016-01-01

Background Bullying victimization in childhood is associated with a broad array of serious mental health disturbances, including anxiety, depression, and suicidal ideation and behavior. The key goal of this study was to evaluate whether bullying victimization is a true environmental risk factor for psychiatric disturbance using data from 145 bully-discordant monozygotic (MZ) juvenile twin pairs from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) and their follow-up into young adulthood. Method Since MZ twins share an identical genotype and familial environment, a higher rate of psychiatric disturbance in a bullied MZ twin compared to their non-bullied MZ co-twin would be evidence of an environmental impact of bullying victimization. Environmental correlations between being bullied and the different psychiatric traits were estimated by fitting structural equation models to the full sample of MZ and DZ twins (N = 2824). Environmental associations were further explored using the longitudinal data on the bullying-discordant MZ twins. Results Being bullied was associated with a wide range of psychiatric disorders in both children and young adults. The analysis of data on the MZ-discordant twins supports a genuine environmental impact of bullying victimization on childhood social anxiety [odds ratio (OR) 1.7], separation anxiety (OR 1.9), and young adult suicidal ideation (OR 1.3). There was a shared genetic influence on social anxiety and bullying victimization, consistent with social anxiety being both an antecedent and consequence of being bullied. Conclusion Bullying victimization in childhood is a significant environmental trauma and should be included in any mental health assessment of children and young adults. PMID:26979565

Familiality and Heritability of Fatigue in an Australian Twin Sample.

PubMed

Corfield, Elizabeth C; Martin, Nicholas G; Nyholt, Dale R

2017-06-01

Familial factors have previously been implicated in the etiology of fatigue, of which a significant proportion is likely attributable to genetic influences. However, family studies have primarily focused on chronic fatigue syndrome, while univariate twin studies have investigated broader fatigue phenotypes. The results for similar fatigue phenotypes vary between studies, particularly with regard to sex-specific contributions to the heritability of the traits. Therefore, the current study aims to investigate the familiality and sex-specific effects of fatigue experienced over the past few weeks in an older Australian population of 660 monozygotic (MZ) twin pairs, 190 MZ singleton twins, 593 dizygotic (DZ) twin pairs, and 365 DZ singleton twins. Higher risks for fatigue were observed in MZ compared to DZ co-twins of probands with fatigue. Univariate heritability analyses indicated fatigue has a significant genetic component, with a heritability (h 2) estimate of 40%. Sex-specific effects did not significantly contribute to the heritability of fatigue, with similar estimates for males (h 2 = 41%, 95% CI [18, 62]) and females (h 2 = 40%, 95% CI [27, 52]). These results indicate that fatigue experienced over the past few weeks has a familial contribution, with additive genetic factors playing an important role in its etiology.

Comparison of Genomic and Epigenomic Expression in Monozygotic Twins Discordant for Rett Syndrome

PubMed Central

Kunio, Miyake; Yang, Chunshu; Minakuchi, Yohei; Ohori, Kenta; Soutome, Masaki; Hirasawa, Takae; Kazuki, Yasuhiro; Adachi, Noboru; Suzuki, Seiko; Itoh, Masayuki; Goto, Yu-ichi; Andoh, Tomoko; Kurosawa, Hiroshi; Akamatsu, Wado; Ohyama, Manabu; Okano, Hideyuki; Oshimura, Mitsuo; Sasaki, Masayuki; Toyoda, Atsushi; Kubota, Takeo

2013-01-01

Monozygotic (identical) twins have been widely used in genetic studies to determine the relative contributions of heredity and the environment in human diseases. Discordance in disease manifestation between affected monozygotic twins has been attributed to either environmental factors or different patterns of X chromosome inactivation (XCI). However, recent studies have identified genetic and epigenetic differences between monozygotic twins, thereby challenging the accepted experimental model for distinguishing the effects of nature and nurture. Here, we report the genomic and epigenomic sequences in skin fibroblasts of a discordant monozygotic twin pair with Rett syndrome, an X-linked neurodevelopmental disorder characterized by autistic features, epileptic seizures, gait ataxia and stereotypical hand movements. The twins shared the same de novo mutation in exon 4 of the MECP2 gene (G269AfsX288), which was paternal in origin and occurred during spermatogenesis. The XCI patterns in the twins did not differ in lymphocytes, skin fibroblasts, and hair cells (which originate from ectoderm as does neuronal tissue). No reproducible differences were detected between the twins in single nucleotide polymorphisms (SNPs), insertion-deletion polymorphisms (indels), or copy number variations. Differences in DNA methylation between the twins were detected in fibroblasts in the upstream regions of genes involved in brain function and skeletal tissues such as Mohawk Homeobox (MKX), Brain-type Creatine Kinase (CKB), and FYN Tyrosine Kinase Protooncogene (FYN). The level of methylation in these upstream regions was inversely correlated with the level of gene expression. Thus, differences in DNA methylation patterns likely underlie the discordance in Rett phenotypes between the twins. PMID:23805272

Comparison of Genomic and Epigenomic Expression in Monozygotic Twins Discordant for Rett Syndrome.

PubMed

Miyake, Kunio; Yang, Chunshu; Minakuchi, Yohei; Ohori, Kenta; Soutome, Masaki; Hirasawa, Takae; Kazuki, Yasuhiro; Adachi, Noboru; Suzuki, Seiko; Itoh, Masayuki; Goto, Yu-Ichi; Andoh, Tomoko; Kurosawa, Hiroshi; Oshimura, Mitsuo; Sasaki, Masayuki; Toyoda, Atsushi; Kubota, Takeo

2013-01-01

Monozygotic (identical) twins have been widely used in genetic studies to determine the relative contributions of heredity and the environment in human diseases. Discordance in disease manifestation between affected monozygotic twins has been attributed to either environmental factors or different patterns of X chromosome inactivation (XCI). However, recent studies have identified genetic and epigenetic differences between monozygotic twins, thereby challenging the accepted experimental model for distinguishing the effects of nature and nurture. Here, we report the genomic and epigenomic sequences in skin fibroblasts of a discordant monozygotic twin pair with Rett syndrome, an X-linked neurodevelopmental disorder characterized by autistic features, epileptic seizures, gait ataxia and stereotypical hand movements. The twins shared the same de novo mutation in exon 4 of the MECP2 gene (G269AfsX288), which was paternal in origin and occurred during spermatogenesis. The XCI patterns in the twins did not differ in lymphocytes, skin fibroblasts, and hair cells (which originate from ectoderm as does neuronal tissue). No reproducible differences were detected between the twins in single nucleotide polymorphisms (SNPs), insertion-deletion polymorphisms (indels), or copy number variations. Differences in DNA methylation between the twins were detected in fibroblasts in the upstream regions of genes involved in brain function and skeletal tissues such as Mohawk Homeobox (MKX), Brain-type Creatine Kinase (CKB), and FYN Tyrosine Kinase Protooncogene (FYN). The level of methylation in these upstream regions was inversely correlated with the level of gene expression. Thus, differences in DNA methylation patterns likely underlie the discordance in Rett phenotypes between the twins.

The TWINS Science Data System after the launch of TWINS 1

NASA Astrophysics Data System (ADS)

Goldstein, J.; Valek, P.; Skoug, R.; Delapp, D.; Redfern, J.; Carruth, B.; McComas, D.

2007-05-01

The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) 1 satellite is in orbit and science data are expected to commence in the near future. TWINS-1 comprises half of the TWINS stereoscopic neutral atom imaging system that will advance our knowledge of the Earth's ring current. To support the expected data return, we have developed a Science Data System (SDS) for the TWINS mission. The TWINS SDS is an IDL- and Java- driven data interface that operates primarily via a web browser, and has as its spine an SQL-queryable database. Through this interface, TWINS science data will be provided to the TWINS team, the space science community, and the public. In this paper we present the current and future capabilities of the TWINS SDS, as well as how the SDS fits into virtual observatory infrastructure.

Does Learning to Read Improve Intelligence? A Longitudinal Multivariate Analysis in Identical Twins from Age 7 to 16

ERIC Educational Resources Information Center

Ritchie, Stuart J.; Bates, Timothy C.; Plomin, Robert

2015-01-01

Evidence from twin studies points to substantial environmental influences on intelligence, but the specifics of this influence are unclear. This study examined one developmental process that potentially causes intelligence differences: learning to read. In 1,890 twin pairs tested at 7, 9, 10, 12, and 16 years, a cross-lagged…

Environmental and Genetic Influence on Dimensions of Perceived Parenting: A Twin Study.

ERIC Educational Resources Information Center

Rowe, David C.

Determinants of Schaefer's (1965) three dimensions of perceived parenting (Acceptance vs. Rejection, Psychological Control vs. Psychological Autonomy, and Firm vs. Lax Control) were investigated by administering a shortened Children's Reports of Parental Behavior Inventory to adolescent twins. The sample consisted of 46 pairs of identical twins…

Co-twin control designs for testing behavioral economic theories of child nutrition: methodological note.

PubMed

Faith, M S; Rose, E; Matz, P E; Pietrobelli, A; Epstein, L H

2006-10-01

To illustrate the use and potential efficiency of the co-twin control design for testing behavioral economic theories of child nutrition. Co-twin control design, in which participating twins ate an ad libitum lunch on two laboratory visits. At visit 1, child food choices were not reinforced. On visit 2, twins were randomized to conditions such that one twin was reinforced for each fruit and vegetable serving consumed during lunch ('contingent') while his co-twin was reinforced irrespective of food intake ('non-contingent'). Six male twins, 5 years old, from three monozygotic twin pairs. Ad libitum intake of total energy (kcals), fat (kcals), and fruits and vegetables (servings) from the protocol test meals on the two visits. Compared to twins receiving non-contingent reinforcement, twins receiving contingent reinforcement increased fruit and vegetable intake by 2.0 servings, reduced fat intake 106.3 kcals, and reduced total energy intake by 112.7 kcals. The relative efficiency of the co-twin control design compared to a conventional between-groups design of unrelated children was most powerful for detecting 'substitution effects' (i.e., reduced total energy and fat intake) more so than for detecting increased fruit and vegetable intake. Genetically informative studies, including the co-twin control design, can provide conceptually elegant and efficient strategies for testing environmental theories of child nutrition and obesity.

Intragranular twinning, detwinning, and twinning-like lattice reorientation in magnesium alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Wei; Gao, Yanfei; Li, Nan

2016-12-01

Deformation twinning plays a critical role on improving metals or alloys ductility, especially for hexagonal close-packed materials with low symmetry crystal structure. A rolled Mg alloy was selected as a model system to investigate the extension twinning behaviors and characteristics of parent-twin interactions by nondestructive in situ 3D synchrotron X-ray microbeam diffraction. Besides twinning-detwinning process, the "twinning-like" lattice reorientation process was captured within an individual grain inside a bulk material during the strain reversal. The distributions of parent, twin, and reorientated grains and sub-micron level strain variation across the twin boundary are revealed. A theoretical calculation of the lattice strainmore » confirms that the internal strain distribution in parent and twinned grains correlates with the experimental setup, grain orientation of parent, twin, and surrounding grains, as well as the strain path changes. The study suggests a novel deformation mechanism within the hexagonal close-packed structure that cannot be determined from surface-based characterization methods. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.« less

Intragranular twinning, detwinning, and twinning-like lattice reorientation in magnesium alloys

DOE PAGES

Wu, Wei; Gao, Yanfei; Oak Ridge National Lab.; ...

2016-09-11

We present that deformation twinning plays a critical role on improving metals or alloys ductility, especially for hexagonal close-packed materials with low symmetry crystal structure. A rolled Mg alloy was selected as a model system to investigate the extension twinning behaviors and characteristics of parent-twin interactions by nondestructive in situ 3D synchrotron X-ray microbeam diffraction. Besides twinning- detwinning process, the twinning-like lattice reorientation process was captured within an individual grain inside a bulk material during the strain reversal. The distributions of parent, twin, and reorientated grains and sub-micron level strain variation across the twin boundary are revealed. A theoretical calculationmore » of the lattice strain confirms that the internal strain distribution in parent and twinned grains correlates with the experimental setup, grain orientation of parent, twin, and surrounding grains, as well as the strain path changes. In conclusion, the study suggests a novel deformation mechanism within the hexagonal close-packed structure that cannot be determined from surface-based characterization methods.« less

Men's sexual interest in children: one-year incidence and correlates in a population-based sample of Finnish male twins.

PubMed

Santtila, Pekka; Antfolk, Jan; Räfså, Anna; Hartwig, Maria; Sariola, Heikki; Sandnabba, N Kenneth; Mokros, Andreas

2015-01-01

In a study of 1,310 Finnish adult male twins we found that sexual interest in children aged 12 or younger was reported by 0.2% of the sample. Sexual interest in children aged 15 or younger was reported by 3.3%. Participants reporting sexual interest in children aged 15 or younger were younger, reported stronger sexual desire, and had experienced more childhood sexual and nonsexual abuse. The present study is the first to give a population-based estimate of the incidence of sexual interest in children among adult men. The 12-month incidence of sexual interest in children below the age of 16 years is roughly comparable to the one-year incidence of major depression or the lifetime prevalence of transvestitic fetishism.

Twins and Kindergarten Separation: Divergent Beliefs of Principals, Teachers, Parents, and Twins

ERIC Educational Resources Information Center

Gordon, Lynn Melby

2015-01-01

Should principals enforce mandatory separation of twins in kindergarten? Do school separation beliefs of principals differ from those of teachers, parents of twins, and twins themselves? This survey questioned 131 elementary principals, 54 kindergarten teachers, 201 parents of twins, and 112 twins. A majority of principals (71%) believed that…

Congenital infantile myofibroma causing intrauterine death in a twin

PubMed Central

Aye, Christina Yi Ling; Gould, Steve; Akinsola, S Adeyemi

2011-01-01

While infantile myofibromatosis is the most common mesenchymal tumour of infancy, only around 300 cases have been reported. The authors report a 33-year-old para 1 with an uncomplicated, dichorionic diamniotic twin pregnancy who was diagnosed with an intrauterine death of one twin at 36+5 weeks gestation. At caesarean section, a macerated male stillborn weighing 2.72 kg was delivered. Postmortem examination revealed a pedunculated lesion attached to the left shoulder and underlying muscle consistent with a congenital myofibroma. The cause of death was postulated to be haemorrhage from the tumour surface causing fetal anaemia. PMID:22674951

Leisure-time physical activity and intra-abdominal fat in young adulthood: A monozygotic co-twin control study.

PubMed

Rottensteiner, Mirva; Leskinen, Tuija; Järvelä-Reijonen, Elina; Väisänen, Karoliina; Aaltonen, Sari; Kaprio, Jaakko; Kujala, Urho M

2016-05-01

To investigate differences in abdominal fat compartments between young adult monozygotic twin pairs discordant for leisure-time physical activity. Ten young adult male monozygotic twin pairs (age range 32-36 years) discordant for leisure-time physical activity during the past 3 years were systematically selected from a population-based Finnish twin cohort. Magnetic resonance image at the level of the L2-L3 intervertebral disc was used to predict intra-abdominal and subcutaneous abdominal fat masses. Dietary intake was assessed with a 4-day food diary. Inactive twins had 31% more intra-abdominal fat than their active co-twins (mean difference 0.52 kg, 95% CI 0.12 to 0.91, P = 0.016), whereas the difference in subcutaneous abdominal fat was only 13% (P = 0.21) and 3% in body mass index (P = 0.28). Intraperitoneal fat mass was 41% higher among inactive twins compared to their active co-twins (mean difference 0.41 kg, 95% CI 0.11 to 0.70, P = 0.012). Dietary intake did not differ between co-twins. A lower level of physical activity is related to greater accumulation of intra-abdominal fat among healthy adult males in their mid-30s. The findings highlight the importance of leisure-time physical activity independent of genes and diet in the prevention of intra-abdominal fat accumulation from early adulthood onward. © 2016 The Obesity Society.

Why is infant mortality higher in boys than in girls? A new hypothesis based on preconception environment and evidence from a large sample of twins.

PubMed

Pongou, Roland

2013-04-01

Infant mortality is higher in boys than girls in most parts of the world. This has been explained by sex differences in genetic and biological makeup, with boys being biologically weaker and more susceptible to diseases and premature death. At the same time, recent studies have found that numerous preconception or prenatal environmental factors affect the probability of a baby being conceived male or female. I propose that these environmental factors also explain sex differences in mortality. I contribute a new methodology of distinguishing between child biology and preconception environment by comparing male-female differences in mortality across opposite-sex twins, same-sex twins, and all twins. Using a large sample of twins from sub-Saharan Africa, I find that both preconception environment and child biology increase the mortality of male infants, but the effect of biology is substantially smaller than the literature suggests. I also estimate the interacting effects of biology with some intrauterine and external environmental factors, including birth order within a twin pair, social status, and climate. I find that a twin is more likely to be male if he is the firstborn, born to an educated mother, or born in certain climatic conditions. Male firstborns are more likely to survive than female firstborns, but only during the neonatal period. Finally, mortality is not affected by the interactions between biology and climate or between biology and social status.

Twinning of dodecanedicarboxylic acid

NASA Technical Reports Server (NTRS)

Sen, R.; Wilcox, W. R.

1986-01-01

Twinning of 1,10-dodecanedicarboxyl acid (DDA) was observed in 0.1 mm thick films with a polarizing microscope. Twins originated from polycrystalline regions which tended to nucleate on twin faces, and terminated by intersection gone another. Twinning increased dramatically with addition of organic compounds with a similar molecular size and shape. Increasing the freezing rate, increasing the temperature gradient, and addition of silica particles increased twinning. It is proposed that twins nucleate with polycrystals and sometimes anneal out before they become observable. The impurities may enhance twinning either by lowering the twin energy or by adsorbing on growing faces.

Are twins at risk of cancer: results from the Swedish family-cancer database.

PubMed

Hemminki, Kari; Chen, Bowang

2005-10-01

A few twin studies on cancer have addressed questions on the possible carcinogenic or protective effects of twining by comparing the occurrence of cancer in twins and singletons. The nationwide Swedish Family-Cancer Database of 10.2 million individuals and 69,654 0- to 70-year-old twin pairs were used to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for all main cancers compared to singletons. The overall risk of cancer in same- or different-sex twins was at the same level as the risk for singletons. Testicular cancer, particularly seminoma, was increased among same-sex twins (1.54) and all twins to an SIR of 1.38. Among other tumors, neurinomas and non-thyroid endocrine gland tumors were increased. Colorectal cancers and leukemia were decreased among all twins. Melanoma and squamous cell skin cancer were decreased in male same-sex twins. The data on this unselected population of twins suggest that twinning per se is not a risk factor of cancer. In utero hormonal exposures or postnatal growth stimulation may be related to the risk of testicular cancer and pituitary tumors. Protective effects against colorectal cancer may be related to a beneficial diet, and in melanoma and skin cancer, to socioeconomic factors. The study involved multiple comparisons, and internal consistency between the results was one of the main factors considered for their plausibility. The results should encourage others working on twin and singleton populations to examine the specific associations and emerging hypotheses.

Male social workers working with men who batter: dilemmas in gender identity.

PubMed

Bailey, Benjamin; Buchbinder, Eli; Eisikovits, Zvi

2011-06-01

Research into the impact of dealing with intimate partner violence has focused mainly on women who treated victims. The present article explores the interaction between male social workers and battering men. The sample included 15 male social workers who worked with battering men in social services. Data collection was performed through semistructured interviews. The main theme emerging from the interviews describes the reconstruction and renegotiation of the worker's professional and personal self in light of his experiences with violent clients. Two major motifs describing their experience emerged: The first is self-doubt arising from adopting a broad definition of violence, thus creating increased sensitization to and inclusion of a wide range of behaviors under the term violence . The second motif is related to compromising with reality by renegotiating their identity as aggressive, at times, but not violent. Findings were discussed in the light of the constructionist perspective.

Malaysian Twin Registry.

PubMed

Jahanfar, Shayesteh; Jaffar, Sharifah Halimah

2013-02-01

The National Malaysian Twin Registry was established in Royal College of Medicine, Perak, University Kuala Lumpur (UniKL) in June 2008 through a grant provided by UniKL. The general objective is to facilitate scientific research involving participation of twins and their family members in order to answer questions of health and wellbeing relevant to Malaysians. Recruitment is done via mass media, poster, and pamphlets. We now have 266 adult and 204 children twins registered. Several research projects including reproductive health study of twins and the role of co-bedding on growth and development of children are carried out. Registry holds annual activities for twins and seeks to provide health-related information for twins. We seek international collaboration.

Chinmo prevents transformer alternative splicing to maintain male sex identity.

PubMed

Grmai, Lydia; Hudry, Bruno; Miguel-Aliaga, Irene; Bach, Erika A

2018-02-01

Reproduction in sexually dimorphic animals relies on successful gamete production, executed by the germline and aided by somatic support cells. Somatic sex identity in Drosophila is instructed by sex-specific isoforms of the DMRT1 ortholog Doublesex (Dsx). Female-specific expression of Sex-lethal (Sxl) causes alternative splicing of transformer (tra) to the female isoform traF. In turn, TraF alternatively splices dsx to the female isoform dsxF. Loss of the transcriptional repressor Chinmo in male somatic stem cells (CySCs) of the testis causes them to "feminize", resembling female somatic stem cells in the ovary. This somatic sex transformation causes a collapse of germline differentiation and male infertility. We demonstrate this feminization occurs by transcriptional and post-transcriptional regulation of traF. We find that chinmo-deficient CySCs upregulate tra mRNA as well as transcripts encoding tra-splice factors Virilizer (Vir) and Female lethal (2)d (Fl(2)d). traF splicing in chinmo-deficient CySCs leads to the production of DsxF at the expense of the male isoform DsxM, and both TraF and DsxF are required for CySC sex transformation. Surprisingly, CySC feminization upon loss of chinmo does not require Sxl but does require Vir and Fl(2)d. Consistent with this, we show that both Vir and Fl(2)d are required for tra alternative splicing in the female somatic gonad. Our work reveals the need for transcriptional regulation of tra in adult male stem cells and highlights a previously unobserved Sxl-independent mechanism of traF production in vivo. In sum, transcriptional control of the sex determination hierarchy by Chinmo is critical for sex maintenance in sexually dimorphic tissues and is vital in the preservation of fertility.

Chinmo prevents transformer alternative splicing to maintain male sex identity

PubMed Central

Hudry, Bruno; Miguel-Aliaga, Irene

2018-01-01

Reproduction in sexually dimorphic animals relies on successful gamete production, executed by the germline and aided by somatic support cells. Somatic sex identity in Drosophila is instructed by sex-specific isoforms of the DMRT1 ortholog Doublesex (Dsx). Female-specific expression of Sex-lethal (Sxl) causes alternative splicing of transformer (tra) to the female isoform traF. In turn, TraF alternatively splices dsx to the female isoform dsxF. Loss of the transcriptional repressor Chinmo in male somatic stem cells (CySCs) of the testis causes them to “feminize”, resembling female somatic stem cells in the ovary. This somatic sex transformation causes a collapse of germline differentiation and male infertility. We demonstrate this feminization occurs by transcriptional and post-transcriptional regulation of traF. We find that chinmo-deficient CySCs upregulate tra mRNA as well as transcripts encoding tra-splice factors Virilizer (Vir) and Female lethal (2)d (Fl(2)d). traF splicing in chinmo-deficient CySCs leads to the production of DsxF at the expense of the male isoform DsxM, and both TraF and DsxF are required for CySC sex transformation. Surprisingly, CySC feminization upon loss of chinmo does not require Sxl but does require Vir and Fl(2)d. Consistent with this, we show that both Vir and Fl(2)d are required for tra alternative splicing in the female somatic gonad. Our work reveals the need for transcriptional regulation of tra in adult male stem cells and highlights a previously unobserved Sxl-independent mechanism of traF production in vivo. In sum, transcriptional control of the sex determination hierarchy by Chinmo is critical for sex maintenance in sexually dimorphic tissues and is vital in the preservation of fertility. PMID:29389999

NOTE: Haemodynamic resistance model of monochorionic twin pregnancies complicated by acardiac twinning

NASA Astrophysics Data System (ADS)

Umur, Asli; van Gemert, Martin J. C.; van den Wijngaard, Jeroen P. H. M.; Ross, Michael G.; Nikkels, Peter G. J.

2004-07-01

An acardiac twin is a severely malformed monochorionic twin fetus that lacks most organs, particularly a heart. It grows during pregnancy, because it is perfused by its developmentally normal co-twin (called the pump twin) via a set of placental arterioarterial and venovenous anastomoses. The pump twin dies intrauterine or neonatally in about 50% of the cases due to congestive heart failure, polyhydramnios and prematurity. Because the pathophysiology of this pregnancy is currently incompletely understood, we modified our previous haemodynamic model of monochorionic twins connected by placental vascular anastomoses to include the analysis of acardiac twin pregnancies. We incorporated the fetoplacental circulation as a resistance circuit and used the fetal umbilical flow that perfuses the body to define fetal growth, rather than the placental flow as done previously. Using this modified model, we predicted that the pump twin has excess blood volume and increased mean arterial blood pressure compared to those in the acardiac twin. Placental perfusion of the acardiac twin is significantly reduced compared to normal, as a consequence of an increased venous pressure, possibly implying reduced acardiac placental growth. In conclusion, the haemodynamic analysis may contribute to an increased knowledge of the pathophysiologic consequences of an acardiac body mass for the pump twin.

Twins and non-twin siblings: different estimates of shared environmental influence in early childhood.

PubMed

Koeppen-Schomerus, Gesina; Spinath, Frank M; Plomin, Robert

2003-04-01

Twin studies typically indicate shared environmental influence for cognitive abilities, especially in early childhood. However, across studies, DZ twin correlations tend to be greater than non-twin sibling correlations, suggesting that twin estimates of shared environment are to some extent specific to twins. We tested this hypothesis in a sample of more than 1800 MZ and 1800 same-sex DZ pairs from the Twins Early Development Study (TEDS), a study of twins born in England and Wales in 1994 and 1995. For this analysis, we obtained comparable data from more than 130 same-sex younger siblings of the twins. Twins and their younger siblings were assessed for language, cognitive abilities and behavior problems by their parents at 2 and 3 years of age. For language and cognitive measures at both 2 and 3 years, but not for behavior problems, estimates of shared environment were more than twice as large for twins as compared to non-twin siblings. We conclude that about half of twin study estimates of shared environment for cognitive abilities in early childhood are specific to twins. Although many possibilities exist for explaining the special shared environment effect for twins, we suggest that cognitive-relevant experiences that are not shared by siblings are shared by twins because they are exactly the same age.

Twins and the paradox of dental-age estimations: a caution for researchers and clinicians.

PubMed

Pechníková, M; De Angelis, D; Gibelli, D; Vecchio, V; Cameriere, R; Zeqiri, B; Cattaneo, C

2014-08-01

The biological age difference among twins is frequently an issue in studies of genetic influence on various dental features, particularly dental development. The timing of dental development is a crucial issue also for many clinicians and researchers. The aim of this study was therefore to verify within groups of twins how dental development differs, by applying Demirjian's method, Mincer's charts of development of third molars and two of Cameriere's methods for dental age estimation, which are among the most popular methods both in the clinical and the forensic scenario. The sample consisted of 64 twin pairs: 21 monozygotic, 30 dizygotic same-sex and 13 dizygotic opposite-sex with an age range between 5.8 and 22.6 years. Dental age was determined from radiographs using the mentioned methods. Results showed that dental age of monozygotic twins is not identical even if they share all their genes. The mean intra-pair difference of monozygotic pairs was low and similar to the difference in dizygotic same-sex twins; the maximum difference between monozygotic twins, however, was surprisingly large (nearly two years). This should lead to some circumspection in the interpretation of systematic estimations of dental age both in the clinical and forensic scenario. Copyright © 2014 Elsevier GmbH. All rights reserved.

Habitual dietary intake is associated with stool microbiota composition in monozygotic twins.

PubMed

Simões, Catarina D; Maukonen, Johanna; Kaprio, Jaakko; Rissanen, Aila; Pietiläinen, Kirsi H; Saarela, Maria

2013-04-01

The impact of diet on the gut microbiota has usually been assessed by subjecting people to the same controlled diet and thereafter following the shifts in the microbiota. In the present study, we used habitual dietary intake, clinical data, quantitative polymerase chain reaction, and denaturing gradient gel electrophoresis (DGGE) to characterize the stool microbiota of Finnish monozygotic twins. The effect of diet on the numbers of bacteria was described through a hierarchical linear mixed model that included the twin individuals, stratified by body mass index, and their families as random effects. The abundance and diversity of the bacterial groups studied did not differ between normal-weight, overweight, and obese individuals with the techniques used. Intakes of energy, monounsaturated fatty acids, n3 polyunsaturated fatty acids (PUFAs), n6 PUFAs, and soluble fiber had significant associations with the stool bacterial numbers (e.g., increased energy intake was associated with reduced numbers of Bacteroides spp.). In addition, co-twins with identical energy intake had more similar numbers and DGGE-profile diversities of Bacteroides spp. than did the co-twins with different intake. Moreover, the co-twins who ingested the same amounts of saturated fatty acids had very similar DGGE profiles of Bacteroides spp., whereas the co-twins with similar consumption of fiber had a very low bifidobacterial DGGE-profile similarity. In conclusion, our findings confirm that the diet plays an important role in the modulation of the stool microbiota, in particular Bacteroides spp. and bifidobacteria.

Descriptive Study of Gender Dysphoria in Japanese Individuals with Male-to-Female Gender Identity Disorder.

PubMed

Shinohara, Yoshie; Nakatsuka, Mikiya

2018-04-01

We focus on Japanese individuals with gender identity disorder (GID), especially male-to-female (MTF) GID, who have experienced difficulty in adapting to social life. We clarify what gender dysphoria is, and we examine methods of intervention. Semi-structured interviews were conducted with 11 individuals with MTF-GID from August 2015 to April 2017. We categorized the subjects'experiences regarding dysphoria into the 'Onset of gender dysphoria,' 'Experience of feeling gender dysphoria,' and 'Changes due to receiving medical care.' The subjects reported experiencing great pain and distress because they did not fully understand that they were experiencing dysphoria and could not align their gender identity and their self-identity. All subjects described their experiences of dysphoria as negative. Additionally, all said that the dysphoria was alleviated by a medical intervention such as visiting a gender clinic, receiving a diagnosis and treatment, and changing their physical sex to the sex congruent with their gender identity. The provision of information at the gender clinic and the physical changes achieved by medical intervention exerted a positive effect both mentally and socially on the subjects, who suffered various physical, mental and social problems.

The Stability of Genetic Determination from Age 2 to Age 9: A Longitudinal Twin Study.

ERIC Educational Resources Information Center

Lytton, Hugh; And Others

A longitudinal investigation of the social and cognitive development of male twins was conducted when twins were 2.5 years of age, and again when they were 8- to 10-years-old. This study was designed to re-examine the heritability of the traits studied at the earlier age and, thus, to address the question of the stability of genetic determination.…

Association between subjective memory complaints and depressive symptoms after adjustment for genetic and family environmental factors in a Japanese twin study.

PubMed

Tanaka, Haruka; Ogata, Soshiro; Omura, Kayoko; Honda, Chika; Kamide, Kei; Hayakawa, Kazuo

2016-03-01

The aim of this study was to investigate the association between subjective memory complaints (SMCs) and depressive symptoms, with and without adjustment for genetic and family environmental factors. We conducted a cross-sectional study using twins and measured SMCs and depressive symptoms as outcomes and explanatory variables, respectively. First, we performed regression analyses using generalized estimating equations to investigate the associations between SMCs and depressive symptoms without adjustment for genetic and family environmental factors (individual-level analyses). We then performed regression analyses for within-pair differences using monozygotic (MZ) and dizygotic (DZ) twin pairs and MZ twin pairs to investigate these associations with adjustment for genetic and family environmental factors by subtracting the values of one twin from those of co-twin variables (within-pair level analyses). Therefore, differences between the associations at individual- and within-pair level analyses suggested confounding by genetic factors. We included 556 twins aged ≥ 20 years. In the individual-level analyses, SMCs were significantly associated with depressive symptoms in both males and females [standardized coefficients: males, 0.23 (95% CI 0.08-0.38); females, 0.35 (95% CI 0.23-0.46)]. In the within-pair level analyses using MZ and same-sex DZ twin pairs, SMCs were significantly associated with depressive symptoms. In the within-pair level analyses using the MZ twin pairs, SMCs were significantly associated with depressive symptoms [standardized coefficients: males, 0.32 (95% CI 0.08-0.56); females, 0.24 (95% CI 0.13-0.42)]. This study suggested that SMCs were significantly associated with depressive symptoms after adjustment for genetic and family environmental factors.

Twin Similarities in Holland Types as Shown by Scores on the Self-Directed Search

ERIC Educational Resources Information Center

Chauvin, Ida; McDaniel, Janelle R.; Miller, Mark J.; King, James M.; Eddlemon, Ondie L. M.

2012-01-01

This study examined the degree of similarity between scores on the Self-Directed Search from one set of identical twins. Predictably, a high congruence score was found. Results from a biographical sheet are discussed as well as implications of the results for career counselors.

Diprosopus conjoined twins: radiologic, autoptic, and histologic study of a case.

PubMed

D'Armiento, Maria; Falleti, Jessica; Maruotti, Giuseppe Maria; Martinelli, Pasquale

2010-01-01

Conjoined twins are a rare and intriguing nature's phenomena; diprosopus or craniofacial duplication is the rarest with a reported incidence of 1 case in 180,000-15 million births. We present a radiologic, autoptic, and histologic study of a 37-week-old male diprosopus twin in a dichorionic pregnancy of a 26-old-year woman. Diprosopus malformation is part of duplication involving face and cranium like janiceps and dicephalus. Our case also shows partial duplication of the stomach with ectopic pancreas. Most studies are required to understand the exact mechanism of this malformation.

Acardiac twin with externalized intestine adherent to placenta: unusual manifestation of omphalocele.

PubMed

Emery, Shawn Clark; Vaux, Keith K; Pretorius, Dolores; Masliah, Eliezer; Benirschke, Kurt

2004-01-01

TRAP (twin reversed arterial perfusion) syndrome produces an acardiac twin (acardiac monster, acardius, acardiacus, chorioangiopagus parasiticus, etc.). Acardiacs result from monozygotic multiple births in which three anatomic anomalies occur: (1) a fetus' cardiac development is disturbed; (2) artery-artery anastomosis carries blood from a normal ("pump") twin to the acardiac; (3) vein-vein anastomosis carries blood from the acardiac back to the normal twin. Whether reversal of blood flow in the acardiac results from or causes cardiac dysmorphogenesis has not been resolved. Acardiac twins demonstrate a complex constellation of malformations usually thought to result from reversed blood flow; omphalocele is particularly common. We report monochorionic monoamnionic male twins in which an acardiac twin demonstrated externalized intestines adherent to the placenta. The twins were delivered from a 30-year-old primigravida mother by cesarean section without maternal complications at 33 w. The mother has no significant past medical history. The macerated acardius had a 4-cm long attenuated umbilical cord with indeterminate number of vessels. Structures rostral to the thorax were absent save for one poorly developed hand and arm. The abdomen contained loose mesenchyme and no organs. The entire intestine (21 cm) along with two testes was located in a sac on the surface of the placenta. No histopathologic anomalies of formed structures were identified aside from spatial relationships and incomplete development. The normal twin required no intensive care and is doing well. To our knowledge, this is the first report of externalized intestine, which may represent an unusual consequence of omphalocele.

Copy Number Variants and Exome Sequencing Analysis in Six Pairs of Chinese Monozygotic Twins Discordant for Congenital Heart Disease.

PubMed

Xu, Yuejuan; Li, Tingting; Pu, Tian; Cao, Ruixue; Long, Fei; Chen, Sun; Sun, Kun; Xu, Rang

2017-12-01

Congenital heart disease (CHD) is one of the most common birth defects. More than 200 susceptibility loci have been identified for CHDs, yet a large part of the genetic risk factors remain unexplained. Monozygotic (MZ) twins are thought to be completely genetically identical; however, discordant phenotypes have been found in MZ twins. Recent studies have demonstrated genetic differences between MZ twins. We aimed to test whether copy number variants (CNVs) and/or genetic mutation differences play a role in the etiology of CHDs by using single nucleotide polymorphism (SNP) genotyping arrays and whole exome sequencing of twin pairs discordant for CHDs. Our goal was to identify mutations present only in the affected twins, which could identify novel candidates for CHD susceptibility loci. We present a comprehensive analysis for the CNVs and genetic mutation results of the selected individuals but detected no consistent differences within the twin pairs. Our study confirms that chromosomal structure or genetic mutation differences do not seem to play a role in the MZ twins discordant for CHD.

Role of alloying elements on twin growth and twin transmission in magnesium alloys

DOE PAGES

Kumar, Mariyappan Arul; Beyerlein, Irene Jane; Lebensohn, Ricardo A.; ...

2017-08-24

A spatially-resolved crystal plasticity Fast Fourier Transform (FFT)-based model is employed to study the effect of alloying addition on twin thickening and twin transmission in hexagonal close packed (HCP) magnesium. In the simulations, the influence of alloying additions is represented through the differences in the critical resolved shear stress (CRSS) of different slip and twinning modes. The results show that for the same grain orientation, twin type and boundary conditions, anisotropy in the CRSS values have a significant effect on twin thickening and twin transmission. Those with large differences in CRSS favor both twin thickening and twin transmission, and vicemore » versa for those with small differences. Furthermore, less difference among the CRSS values enhances the dependence of thickening and transmission on the neighboring grain orientation.« less

Role of alloying elements on twin growth and twin transmission in magnesium alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Mariyappan Arul; Beyerlein, Irene Jane; Lebensohn, Ricardo A.

A spatially-resolved crystal plasticity Fast Fourier Transform (FFT)-based model is employed to study the effect of alloying addition on twin thickening and twin transmission in hexagonal close packed (HCP) magnesium. In the simulations, the influence of alloying additions is represented through the differences in the critical resolved shear stress (CRSS) of different slip and twinning modes. The results show that for the same grain orientation, twin type and boundary conditions, anisotropy in the CRSS values have a significant effect on twin thickening and twin transmission. Those with large differences in CRSS favor both twin thickening and twin transmission, and vicemore » versa for those with small differences. Furthermore, less difference among the CRSS values enhances the dependence of thickening and transmission on the neighboring grain orientation.« less

Just a Knock Back? Identity Bruising on the Route to Becoming a Male Primary School Teacher

ERIC Educational Resources Information Center

Foster, Tor; Newman, Elizabeth

2005-01-01

Men who choose to do "women's work" and enter the female culture of the primary school can often initially face a range of stereotyped responses to their choice. Drawing on stories from a small sample of trainee and serving male teachers, we adopt the term "identity bruising" to describe the "knock backs" that occur…

Associations Between Fast-Food Consumption and Body Mass Index: A Cross-Sectional Study in Adult Twins

PubMed Central

Cohen-Cline, Hannah; Lau, Richard; Moudon, Anne V.; Turkheimer, Eric; Duncan, Glen E.

2015-01-01

Obesity is a substantial health problem in the United States, and is associated with many chronic diseases. Previous studies have linked poor dietary habits to obesity. This cross-sectional study aimed to identify the association between body mass index (BMI) and fast-food consumption among 669 same-sex adult twin pairs residing in the Puget Sound region around Seattle, Washington. We calculated twin-pair correlations for BMI and fast-food consumption. We next regressed BMI on fast-food consumption using generalized estimating equations (GEE), and finally estimated the within-pair difference in BMI associated with a difference in fast-food consumption, which controls for all potential genetic and environment characteristics shared between twins within a pair. Twin-pair correlations for fast-food consumption were similar for identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, but were substantially higher in MZ than DZ twins for BMI. In the unadjusted GEE model, greater fast-food consumption was associated with larger BMI. For twin pairs overall, and for MZ twins, there was no association between within-pair differences in fast-food consumption and BMI in any model. In contrast, there was a significant association between within-pair differences in fast-food consumption and BMI among DZ twins, suggesting that genetic factors play a role in the observed association. Thus, although variance in fast-food consumption itself is largely driven by environmental factors, the overall association between this specific eating behavior and BMI is largely due to genetic factors. PMID:26005202

Associations Between Fast-Food Consumption and Body Mass Index: A Cross-Sectional Study in Adult Twins.

PubMed

Cohen-Cline, Hannah; Lau, Richard; Moudon, Anne V; Turkheimer, Eric; Duncan, Glen E

2015-08-01

Obesity is a substantial health problem in the United States, and is associated with many chronic diseases. Previous studies have linked poor dietary habits to obesity. This cross-sectional study aimed to identify the association between body mass index (BMI) and fast-food consumption among 669 same-sex adult twin pairs residing in the Puget Sound region around Seattle, Washington. We calculated twin-pair correlations for BMI and fast-food consumption. We next regressed BMI on fast-food consumption using generalized estimating equations (GEE), and finally estimated the within-pair difference in BMI associated with a difference in fast-food consumption, which controls for all potential genetic and environment characteristics shared between twins within a pair. Twin-pair correlations for fast-food consumption were similar for identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, but were substantially higher in MZ than DZ twins for BMI. In the unadjusted GEE model, greater fast-food consumption was associated with larger BMI. For twin pairs overall, and for MZ twins, there was no association between within-pair differences in fast-food consumption and BMI in any model. In contrast, there was a significant association between within-pair differences in fast-food consumption and BMI among DZ twins, suggesting that genetic factors play a role in the observed association. Thus, although variance in fast-food consumption itself is largely driven by environmental factors, the overall association between this specific eating behavior and BMI is largely due to genetic factors.

A Discordant Monozygotic Twin Design Shows Blunted Cortisol Reactivity Among Bullied Children

PubMed Central

Ouellet-Morin, Isabelle; Danese, Andrea; Bowes, Lucy; Shakoor, Sania; Ambler, Antony; Pariante, Carmine M.; Papadopoulos, Andrew S.; Caspi, Avshalom; Moffitt, Terrie E.; Arseneault, Louise

2013-01-01

Objective Childhood adverse experiences are known to engender persistent changes in stress-related systems and brain structures involved in mood, cognition, and behavior in animal models. Uncertainty remains about the causal effect of early stressful experiences on physiological response to stress in human beings, as the impact of these experiences has rarely been investigated while controlling for both genetic and shared environmental influences. Method We tested whether bullying victimization, a repeated adverse experience in childhood, influences cortisol responses to a psychosocial stress test (PST) using a discordant monozygotic (MZ) twin design. Thirty pairs (43.3% males) of 12-year-old MZ twins discordant for bullying victimization were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994–1995 cohort of families with twins. Results Bullied and nonbullied MZ twins showed distinct patterns of cortisol secretion after the PST. Specifically, bullied twins exhibited a blunted cortisol response compared with their nonbullied MZ co-twins, who showed the expected increase. This difference in cortisol response to stress could not be attributed to children's genetic makeup, their familial environments, pre-existing and concomitant individual factors, or the perception of stress and emotional response to the PST. Conclusion Results from this natural experiment provide support for a causal effect of adverse childhood experiences on the neuroendocrine response to stress. PMID:21621141

The impact of childhood parental loss on risk for mood, anxiety and substance use disorders in a population-based sample of male twins.

PubMed

Otowa, Takeshi; York, Timothy P; Gardner, Charles O; Kendler, Kenneth S; Hettema, John M

2014-12-15

Previous studies have identified the relationship between parental loss and psychopathology later in life. However, this relationship varied depending on the kind of loss, the parent involved, and the type of psychopathology. In the present study, we examined the association between parental loss (any loss, death, and separation) during childhood and lifetime risk for seven common psychiatric and substance use disorders in a sample of 2605 male twins from the Virginia population-based twin registry. Using structural equation modeling (SEM), we also examined the extent to which the influence of parental loss contributes to adult psychopathology. Parental separation was associated with a wide range of adult psychopathology, whereas parental death was specifically associated with phobia and alcohol dependence. Maternal and paternal separations were almost equally associated with most forms of psychopathology. SEM suggested that parental loss accounted for about 10% of the variance of adult psychopathology, of which parental separation had the strongest impacts on risk for depression and drug abuse/dependence (11% of the total variance). Our findings suggest that early parental separation has stronger and wider effects on adult psychopathology than parental death. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Cord blood level of insulin-like growth factor-1 and IGF binding protein-3 in monochorionic twins.

PubMed

Teng, Ru-Jeng; Wu, Tzong-Jin; Hsieh, Fon-Jou

2015-04-01

Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are known to modulate fetal growth but their role in intrauterine growth of monochorionic twins (MCT) has not been studied. Cord venous blood was collected directly after birth. IGF-1 and IGFBP-3 in the cord venous blood were quantified by radioimmunoassay. Birth weights (BWs) were obtained electronically. Placentas were examined for chorionicity. Cord blood was collected in 37 pairs of MCT (15 pairs were males). BWs ranged from 564 to 3240 g, and gestational ages (GAs) were between 24 weeks and 39 weeks. There was a correlation between BW and cord venous blood IGFBP-3 concentration (r = 0.28, p = 0.015), but not between BW and cord venous blood IGF-1 level. There was no difference in IGF-1 between the heavier twins (30.8 ± 61.8 ng/mL) and lighter twins (33.2 ± 63.7 ng/mL), but a trend (p = 0.096) of higher IGFBP-3 level was demonstrated in heavier twins (3.14 ± 1.23 μg/mL) than in lighter twins (2.71 ± 1.19 μg/mL). The IGFBP-3 levels were higher (p = 0.042) in female twins (3.20 ± 1.33 μg/mL) than in male twins (2.64 ± 1.04 μg/mL). The IGF-1 level of the heavier twins correlated significantly to their lighter co-twin (r = 0.73, p < 0.001). Our data showed that cord venous blood IGF-1 level might be controlled mainly by genetic factors. IGFBP-3 might play an important role in fetal growth. Copyright © 2013. Published by Elsevier B.V.

Twin-Telescope Wettzell (TTW)

NASA Astrophysics Data System (ADS)

Hase, H.; Dassing, R.; Kronschnabl, G.; Schlüter, W.; Schwarz, W.; Lauber, P.; Kilger, R.

2007-07-01

Following the recommendations made by the VLBI2010 vision report of the IVS, a proposal has been made to construct a Twin Telescope for the Fundamental Station Wettzell in order to meet the future requirements of the next VLBI generation. The Twin Telescope consists of two identical radiotelescopes. It is a project of the Federal Agency for Cartography and Geodesy (BKG). This article summarizes the project and some design ideas for the Twin-Telescope. %ZALMA (2005). Technical Specification for Design, Manufacturing, Transport and Integration on Site of the ALMA ANTENNAS, Doc. ALMA-34.00.00.00.006-BSPE. Behrend, D. (2006). VLBI2010 Antenna Specs, Data sheet. DeBoer, D. (2001). The ATA Offset Gregorian Antenna, ATA Memo #16, February 10. Imbriale, W.A. (2006). Design of a Wideband Radio Telescope, Jet Propulsion Laboratory and S. Weinreb and H. Mandi, California Institute of Technology. Kilger, R. (2007). TWIN-Design studies, Presentation for the IVS board members (internal document),Wettzell. Kronschnabl, G. (2006). Subject: Memo from Bill Petrachenko, E-mail to the Twin-Working Group (in German), July. Lindgren, ETS-Lindgren (2005). The Model 3164-05 Open Boundary Quadridge Horn, Data Sheet. Niell, A., A. Whitney, W. Petrachenko, W. Schlüter, N. Vandenberg, H.Hase, Y. Koyama, C. Ma, H. Schuh, G. Tucari (2006). in: IVS Annual Report 2005, pg. 13-40, NASA/TP-2006-214136, April. Olsson, R., Kildal, P.-S., and Weinreb, S. (2006). IEEE Transactions on Antennas and Propagation, Vol. 54, No. 2, February. Petrachenko, B. (2006). The Case For and Against Multiple Antennas at a Site, IVS Memorandum, 2006-019v01. Petrachenko, B. (2006). IVS Memorandum, 2006-016v01. RFSpin (2004). Double Ridged Waveguide Horn-Model DRH20, Antenna Specifications, Data Sheet. Rohde&Schwarz (2004). SHF Antennas Crossed Log- Periodic Antennas HL024A1/S1, Data Sheet. Rohde&Schwarz (2004). SHF Antennas Log-Periodic Antennas HL050/HL050S1, Data Sheet. Rogers, A.E.E. (2006). Simulations of broadband

Heritability of DUI convictions: a twin study of driving under the influence of alcohol.

PubMed

Anum, Emmanuel A; Silberg, Judy; Retchin, Sheldon M

2014-02-01

The study was undertaken to assess the relative contributions of genetic and environmental influences on drunk-driving. Driving records of a cohort of male and female twins (N = 17,360) from the Mid-Atlantic Twin Registry were examined. Structural equation models were used to estimate the magnitude of genetic and environmental effects on male and female phenotypes, and test for gender differences. There were significant gender and age effects. Compared with females, males were five times more likely to engage in driving under the influence. Among persons aged 21-49 years, the risk for drunk-driving was eight times that for those aged 50+ years and five times greater than those ≤20 years. In both males and females, aged 21-49 years, a large proportion (57%) of the variance in drunk-driving was due to genetic factors and the remaining 43% due to individual specific environmental influences. Drunk-driving is under significant genetic influence in both males and females. Our findings suggest that a different set of genes influence DUIs in men and women.

Novel epigenetic changes unveiled by monozygotic twins discordant for smoking habits.

PubMed

Allione, Alessandra; Marcon, Francesca; Fiorito, Giovanni; Guarrera, Simonetta; Siniscalchi, Ester; Zijno, Andrea; Crebelli, Riccardo; Matullo, Giuseppe

2015-01-01

Exposure to cigarette smoking affects the epigenome and could increase the risk of developing diseases such as cancer and cardiovascular disorders. Changes in DNA methylation associated with smoking may help to identify molecular pathways that contribute to disease etiology. Previous studies are not completely concordant in the identification of differentially methylated regions in the DNA of smokers. We performed an epigenome-wide DNA methylation study in a group of monozygotic (MZ) twins discordant for smoking habits to determine the effect of smoking on DNA methylation. As MZ twins are considered genetically identical, this model allowed us to identify smoking-related DNA methylation changes independent from genetic components. We investigated the whole blood genome-wide DNA methylation profiles in 20 MZ twin pairs discordant for smoking habits by using the Illumina HumanMethylation450 BeadChip. We identified 22 CpG sites that were differentially methylated between smoker and non-smoker MZ twins by intra-pair analysis. We confirmed eight loci already described by other groups, located in AHRR, F2RL3, MYOG1 genes, at 2q37.1 and 6p21.33 regions, and also identified several new loci. Moreover, pathway analysis showed an enrichment of genes involved in GTPase regulatory activity. Our study confirmed the evidence of smoking-related DNA methylation changes, emphasizing that well-designed MZ twin models can aid the discovery of novel DNA methylation signals, even in a limited sample population.

Habitual dietary sodium intake is inversely associated with coronary flow reserve in middle-aged male twins1234

PubMed Central

Eufinger, Silvia C; Votaw, John; Faber, Tracy; Ziegler, Thomas R; Goldberg, Jack; Bremner, J Douglas

2012-01-01

Background: Evidence links dietary sodium to hypertension and cardiovascular disease (CVD), but investigation of its influence on cardiovascular function is limited. Objective: We examined the relation between habitual dietary sodium and coronary flow reserve (CFR), which is a measure of overall coronary vasodilator capacity and microvascular function. We hypothesized that increased sodium consumption is associated with lower CFR. Design: Habitual daily sodium intake for the previous 12 mo was measured in 286 male middle-aged twins (133 monozygotic and dizygotic pairs and 20 unpaired twins) by using the Willett food-frequency questionnaire. CFR was measured by positron emission tomography [N13]-ammonia, with quantitation of myocardial blood flow at rest and after adenosine stress. Mixed-effects regression analysis was used to assess the association between dietary sodium and CFR. Results: An increase in dietary sodium of 1000 mg/d was associated with a 10.0% lower CFR (95% CI: −17.0%, −2.5%) after adjustment for demographic, lifestyle, nutritional, and CVD risk factors (P = 0.01). Across quintiles of sodium consumption, dietary sodium was inversely associated with CFR (P-trend = 0.03), with the top quintile (>1456 mg/d) having a 20% lower CFR than the bottom quintile (<732 mg /d). This association also persisted within pairs: a 1000-mg/d difference in dietary sodium between brothers was associated with a 10.3% difference in CFR after adjustment for potential confounders (P = 0.02). Conclusions: Habitual dietary sodium is inversely associated with CFR independent of CVD risk factors and shared familial and genetic factors. Our study suggests a potential novel mechanism for the adverse effects of dietary sodium on the cardiovascular system. This trial was registered at clinicaltrials.gov as NCT00017836. PMID:22258268

Proteomic Assessment of Fluid Shifts and Association with Visual Impairment and Intracranial Pressure in Twin Astronauts

NASA Technical Reports Server (NTRS)

Rana, Brinda K.; Stenger, Michael B.; Lee, Stuart M. C.; Macias, Brandon R.; Siamwala, Jamila; Piening, Brian Donald; Hook, Vivian; Ebert, Doug; Patel, Hemal; Smith, Scott;

Perspectives of Iranian male nursing students regarding the role of nursing education in developing a professional identity: a content analysis study.

PubMed

Vaismoradi, Mojtaba; Salsali, Mahvash; Ahmadi, Fazlollah

2011-12-01

The purpose of the present study was to explore the perspectives of Iranian male nursing students regarding the role of nursing education in developing a professional identity. A qualitative design, based on the content analysis approach, was used to collect the data and analyze the perspectives of 14 Iranian male nursing students who were chosen by using a purposive sampling strategy. After the selection of the participants, semistructured interviews were held in order to collect the data. During the data analysis, three main themes emerged: "reality-expectation incompatibility", "being supported by the educational system", and "nursing image rectification". The second theme consisted of two categories: "feeling trusted" and "being defended". This study will be useful to nurse educators and administrators in relation to what constitutes nursing students' professional identity within the Iranian culture and context and how nursing education can play an effective role in developing their professional identity in order to devise strategies to attract male students to the nursing profession and promote their retention after graduation. © 2010 The Authors. Japan Journal of Nursing Science © 2010 Japan Academy of Nursing Science.

Asymmetric twin Dark Matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farina, Marco

2015-11-09

We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural Dark Matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon Dark Matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. The essential requirements for successful thermal history are presented, and in doing so we address some of themore » cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC.« less

Asymmetric twin Dark Matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farina, Marco, E-mail: mf627@cornell.edu

2015-11-01

We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural Dark Matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon Dark Matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. The essential requirements for successful thermal history are presented, and in doing so we address some of themore » cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC.« less

The Host Genotype and Environment Affect Strain Types of Bifidobacterium longum subsp. longum Inhabiting the Intestinal Tracts of Twins.

PubMed

Zhang, Min; Hang, Xiaomin; Tan, Jing; Yang, Hong

2015-07-01

To investigate the influences of host genotype and environment on Bifidobacterium longum subsp. longum inhabiting human intestines at the strain level, six pairs of twins, divided into two groups (children and adults), were recruited. Each group consisted of two monozygotic (MZ) twin pairs and one dizygotic (DZ) twin pair. Child twins had been living together from birth, while adult twins had been living separately for 5 to 10 years. A total of 345 B. longum subsp. longum isolates obtained from 60 fecal samples from these twins were analyzed by multilocus sequence typing (MLST), and 35 sequence types (STs) were finally acquired. Comparison of strains within and between the twin pairs showed that no strains with identical STs were observed between unrelated individuals or within adult DZ twin pairs. Eight STs were found to be monophyletic, existing within MZ twins and child DZ twins. The similarity of strain types within child cotwins was significantly higher than that within adult cotwins, which indicated that environment was one of the important determinants in B. longum subsp. longum strain types inhabiting human intestines. However, although these differences between MZ and DZ twins were observed, it is still difficult to reach an exact conclusion about the impact of host genotype. This is mainly because of the limited number of subjects tested in the present study and the lack of strain types tracing in the same twin pairs from birth until adulthood. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Complete androgen insensitivity syndrome associated with male gender identity or female precocious puberty in the same family.

PubMed

Bermúdez de la Vega, José A; Fernández-Cancio, Mónica; Bernal, Susana; Audí, Laura

2015-01-01

In 4 complete androgen insensitivity syndrome (CAIS) members of one family, 2 presented extreme and unusual clinical features: male gender identity disorder (case 1) and female precocious central puberty (case 2). The AR gene carried the mutation c.1752C>G, p.Phe584Leu. Gender dysphoria in CAIS may be considered as a true transgender and has been described in 3 other cases. Central precocious puberty has only been described in 1 case; Müllerian ducts in case 2 permitted menarche. Despite the common CAIS phenotype, there was a familial disparity for gender identity adequacy and timing and type of puberty.

Genetic overlap between impulsivity and alcohol dependence: a large-scale national twin study.

PubMed

Khemiri, L; Kuja-Halkola, R; Larsson, H; Jayaram-Lindström, N

2016-04-01

Alcohol dependence is associated with increased levels of impulsivity, but the genetic and environmental underpinnings of this overlap remain unclear. The purpose of the current study was to investigate the degree to which genetic and environmental factors contribute to the overlap between alcohol dependence and impulsivity. Univariate and bivariate twin model fitting was conducted for alcohol dependence and impulsivity in a national sample of 16 819 twins born in Sweden from 1959 to 1985. The heritability estimate for alcohol dependence was 44% [95% confidence interval (CI) 31-57%] for males and 62% (95% CI 52-72%) for females. For impulsivity, the heritability was 33% (95% CI 30-36%) in males and females. The bivariate twin analysis indicated a statistically significant genetic correlation between alcohol dependence and impulsivity of 0.40 (95% CI 0.23-0.58) in males and 0.20 (95% CI 0.07-0.33) in females. The phenotypic correlation between alcohol dependence and impulsivity was 0.20 and 0.17 for males and females, respectively, and the bivariate heritability was 80% (95% CI 47-117%) for males and 53% (95% CI 19-86%) for females. The remaining variance in all models was accounted for by non-shared environmental factors. The association between alcohol dependence and impulsivity can be partially accounted for by shared genetic factors. The genetic correlation was greater in men compared with women, which may indicate different pathways to the development of alcohol dependence between sexes. The observed genetic overlap has clinical implications regarding treatment and prevention, and partially explains the substantial co-morbidity between alcohol dependence and psychiatric disorders characterized by impulsive behaviour.

Physics career intentions: The effect of physics identity, math identity, and gender

NASA Astrophysics Data System (ADS)

Lock, Robynne M.; Hazari, Zahra; Potvin, Geoff

2013-01-01

Although nearly half of high school physics students are female, only 21% of physics bachelor's degrees are earned by women. Using data from a national survey of college students in introductory English courses (on science-related experiences, particularly in high school), we examine the influence of students' physics and math identities on their choice to pursue a physics career. Males have higher math and physics identities than females in all three dimensions of our identity framework. These dimensions include: performance/competence (perceptions of ability to perform/understand), recognition (perception of recognition by others), and interest (desire to learn more). A regression model predicting students' intentions to pursue physics careers shows, as expected, that males are significantly more likely to choose physics than females. Surprisingly, however, when physics and math identity are included in the model, females are shown to be equally likely to choose physics careers as compared to males.

A twin study of differences in the response of plasma ghrelin to a milkshake preload in restrained eaters

PubMed Central

Myhre, Rachel; Kratz, Mario; Goldberg, Jack; Polivy, Janet; Melhorn, Susan; Buchwald, Dedra; Cummings, David E.; Schur, Ellen A.

2014-01-01

Background Genetic, physiological, and psychological factors can affect food intake, but twin studies can distinguish inherited from environmental contributors. We examined the influence of attempted cognitive control of eating (“restrained eating”) on levels of appetite-regulating hormones. Methods Sixteen female, monozygotic twin pairs, discordant for Restraint Scale score (i.e., one twin a restrained eater with score > 15 whereas the co-twin was unrestrained), were selected from the University of Washington Twin Registry. Serial plasma ghrelin concentrations were monitored during meals and a preload study paradigm involving intake of a milkshake followed by an ad libitum ice cream “taste test.” Results Body weight, body mass index, resting energy expenditure, and fasting leptin levels were very similar between restrained and unrestrained twins. In a preload study, twins ate similar amounts of ice cream shortly after drinking identical milkshakes (mean ±SD; restrained 239 ±158 vs. unrestrained 228 ±132 kilocalories; P = 0.83). However, ghrelin concentrations during the preload study were significantly higher (P = 0.03) in restrained twins than in their unrestrained co-twins. Regardless of restraint status, ghrelin levels prior to the preload study were prospectively and positively associated with ice cream intake (P = 0.001). Conclusions Compared to their unrestrained co-twins, restrained twins had higher endogenous ghrelin levels during a preload study, but ate similar amounts. This finding is consistent with exertion of cognitive control relative to the state of physiologic appetite stimulation. Moreover, these findings in twins suggest that higher ghrelin levels result from restrained eating behavior and not from genetic predisposition. PMID:24534168

Discordant sex in monozygotic XXY/XX twins: a case report.

PubMed

Tachon, G; Lefort, G; Puechberty, J; Schneider, A; Jeandel, C; Boulot, P; Prodhomme, O; Meyer, P; Taviaux, S; Touitou, I; Pellestor, F; Geneviève, D; Gatinois, V

2014-12-01

We report a case of discordant phenotypic sex in monozygotic twins mosaic 47,XXY/46,XX: monozygotic heterokaryotypic twins. The twins presented with cognitive and comprehension delay, behavioural and language disorders, all symptoms frequently reported in Klinefelter syndrome. Molecular zygosity analysis with several markers confirmed that the twins are in effect monozygotic (MZ). Array comparative genomic hybridization found no evidence for the implication of copy number variation in the phenotypes. Ultrasound scans of the reproductive organs revealed no abnormalities. Endocrine tests showed a low testosterone level in Twin 1 (male phenotype) and a low gonadotrophin level in Twin 2 (female phenotype) which, combined with the results from ultrasound examination, provided useful information for potentially predicting the future fertility potential of the twins. Blood karyotypes revealed the presence of a normal 46,XX cell line and an aneuploïd 47,XXY cell line in both patients. Examination of the chromosome constitutions of various tissues such as blood, buccal smear and urinary sediment not surprisingly showed different proportions for the 46,XX and 47,XXY cell lines, which most likely explains the discordant phenotypic sex and mild Klinefelter features. The most plausible underlying biological mechanism is a post-zygotic loss of the Y chromosome in an initially 47,XXY zygote. This would result in an embryo with both 46,XX and 47,XXY cells lines which could subsequently divide into two monozygotic embryos through a twinning process. The two cell lines would then be distributed differently between tissues which could result in phenotypic discordances in the twins. These observations emphasize the importance of regular paediatric evaluations to determine the optimal timing for fertility preservation measures and to detect new Klinefelter features which could appear throughout childhood in the two subjects. © The Author 2014. Published by Oxford University Press on

Heritability of carotid intima-media thickness: a twin study.

PubMed

Zhao, Jinying; Cheema, Faiz A; Bremner, J Douglas; Goldberg, Jack; Su, Shaoyong; Snieder, Harold; Maisano, Carisa; Jones, Linda; Javed, Farhan; Murrah, Nancy; Le, Ngoc-Anh; Vaccarino, Viola

2008-04-01

To estimate the heritability of carotid intima-media thickness (IMT), a surrogate marker for atherosclerosis, independent of traditional coronary risk factors. We performed a classical twin study of carotid IMT using 98 middle-aged male twin pairs, 58 monozygotic (MZ) and 40 dizygotic (DZ) pairs, from the Vietnam Era Twin Registry. All twins were free of overt cardiovascular disease. Carotid IMT was measured by ultrasound. Bivariate and multivariate analyses were used to determine the association between traditional cardiovascular risk factors and carotid IMT. Intraclass correlation coefficients and genetic modeling techniques were used to determine the relative contributions of genes and environment to the variation in carotid IMT. In our sample, the mean of the maximum carotid IMT was 0.75+/-0.11. Age, systolic blood pressure and HDL were significantly associated with carotid IMT. The intraclass correlation coefficient for carotid IMT was larger in MZ (0.66; 95% confidence interval [CI], 0.62-0.69) than in DZ twins (0.37; 95% CI, 0.29-0.44), and the unadjusted heritability was 0.69 (95% CI, 0.54-0.79). After adjusting for traditional coronary risk factors, the heritability of carotid IMT was slightly reduced but still of considerable magnitude (0.59; 95% CI, 0.39-0.73). Genetic factors have a substantial influence on the variation of carotid IMT. Most of this genetic effect occurs through pathways independent of traditional coronary risk factors.

Heritability of Carotid Intima-Media Thickness: A Twin Study

PubMed Central

Zhao, Jinying; Cheema, Faiz A.; Bremner, J. Douglas; Goldberg, Jack; Su, Shaoyong; Snieder, Harold; Maisano, Carisa; Jones, Linda; Javed, Farhan; Murrah, Nancy; Le, Ngoc-Anh; Vaccarino, Viola

2008-01-01

Objective To estimate the heritability of carotid intima-media thickness (IMT), a surrogate marker for atherosclerosis, independent of traditional coronary risk factors. Methods and Results We performed a classical twin study of carotid IMT using 98 middle-aged male twin pairs, 58 monozygotic (MZ) and 40 dizygotic (DZ) pairs, from the Vietnam Era Twin Registry. All twins were free of overt cardiovascular disease. Carotid IMT was measured by ultrasound. Bivariate and multivariate analyses were used to determine the association between traditional cardiovascular risk factors and carotid IMT. Intraclass correlation coefficients and genetic modeling techniques were used to determine the relative contributions of genes and environment to the variation in carotid IMT. In our sample, the mean of the maximum carotid IMT was 0.75 ± 0.11. Age, systolic blood pressure and HDL were significantly associated with carotid IMT. The intraclass correlation coefficient for carotid IMT was larger in MZ (0.66; 95% confidence interval [CI], 0.62–0.69) than in DZ twins (0.37; 95% CI, 0.29–0.44), and the unadjusted heritability was 0.69 (95% CI, 0.54–0.79). After adjusting for traditional coronary risk factors, the heritability of carotid IMT was slightly reduced but still of considerable magnitude (0.59; 95% CI, 0.39–0.73). Conclusion Genetic factors have a substantial influence on the variation of carotid IMT. Most of this genetic effect occurs through pathways independent of traditional coronary risk factors. PMID:17825306

Organismal, genetic, and transcriptional variation in the deeply sequenced gut microbiomes of identical twins

PubMed Central

Turnbaugh, Peter J.; Quince, Christopher; Faith, Jeremiah J.; McHardy, Alice C.; Yatsunenko, Tanya; Niazi, Faheem; Affourtit, Jason; Egholm, Michael; Henrissat, Bernard; Knight, Rob; Gordon, Jeffrey I.

2010-01-01

We deeply sampled the organismal, genetic, and transcriptional diversity in fecal samples collected from a monozygotic (MZ) twin pair and compared the results to 1,095 communities from the gut and other body habitats of related and unrelated individuals. Using a new scheme for noise reduction in pyrosequencing data, we estimated the total diversity of species-level bacterial phylotypes in the 1.2-1.5 million bacterial 16S rRNA reads obtained from each deeply sampled cotwin to be ~800 (35.9%, 49.1% detected in both). A combined 1.1 million read 16S rRNA dataset representing 281 shallowly sequenced fecal samples from 54 twin pairs and their mothers contained an estimated 4,018 species-level phylotypes, with each sample having a unique species assemblage (53.4 ± 0.6% and 50.3 ± 0.5% overlap with the deeply sampled cotwins). Of the 134 phylotypes with a relative abundance of >0.1% in the combined dataset, only 37 appeared in >50% of the samples, with one phylotype in the Lachnospiraceae family present in 99%. Nongut communities had significantly reduced overlap with the deeply sequenced twins’ fecal microbiota (18.3 ± 0.3%, 15.3 ± 0.3%). The MZ cotwins’ fecal DNA was deeply sequenced (3.8-6.3 Gbp/sample) and assembled reads were assigned to 25 genus-level phylogenetic bins. Only 17% of the genes in these bins were shared between the cotwins. Bins exhibited differences in their degree of sequence variation, gene content including the repertoire of carbohydrate active enzymes present within and between twins (e.g., predicted cellulases, dockerins), and transcriptional activities. These results provide an expanded perspective about features that make each of us unique life forms and directions for future characterization of our gut ecosystems. PMID:20363958

Why do identical twins differ in personality: shared environment reconsidered.

PubMed

Torgersen, Anne Mari; Janson, Harald

2002-02-01

While heritability studies show that most of the variance in adult personality can be attributed to genetic or so-called nonshared environmental influence, this does not mean that shared events lack importance for the development of later personality differences. We studied the relationship between Big Five personality differences in monozygotic (MZ) twins at age 29, and life stressors at age 6 to 15, using prospective data from 26 MZ pairs studied from birth onwards. A positive significant correlation was found between stressors in childhood and early adolescence, and intrapair personality differences in Agreeableness, Openness, Conscientiousness, and five-factor profiles. We note that the effects of shared events are labeled "nonshared" environment when the effect is to make siblings more different. Case examples illustrate the relationship between stress and personality differences, and provide hypotheses for further studies in larger samples.

The vector-like twin Higgs

DOE PAGES

Craig, Nathaniel; Knapen, Simon; Longhi, Pietro; ...

2016-07-01

Here, we present a version of the twin Higgs mechanism with vector-like top partners. In this setup all gauge anomalies automatically cancel, even without twin leptons. The matter content of the most minimal twin sector is therefore just two twin tops and one twin bottom. The LHC phenomenology, illustrated with two example models, is dominated by twin glueball decays, possibly in association with Higgs bosons. We further construct an explicit four-dimensional UV completion and discuss a variety of UV completions relevant for both vector-like and fraternal twin Higgs models.

Discordant KCNQ1OT1 imprinting in sets of monozygotic twins discordant for Beckwith-Wiedemann syndrome.

PubMed

Weksberg, Rosanna; Shuman, Cheryl; Caluseriu, Oana; Smith, Adam C; Fei, Yan-Ling; Nishikawa, Joy; Stockley, Tracy L; Best, Lyle; Chitayat, David; Olney, Ann; Ives, Elizabeth; Schneider, Adele; Bestor, Timothy H; Li, Madeline; Sadowski, Paul; Squire, Jeremy

2002-05-15

Beckwith-Wiedemann syndrome (BWS) presents with visceromegaly, macroglossia, tumor predisposition and other congenital abnormalities, and is usually associated with abnormalities of chromosome 11p15. A number of identical twin pairs, mostly female, have been reported to be discordant for BWS. We show here that the incidence of female monozygotic twins among patients with BWS is dramatically increased over that of the general population. A cluster of imprinted genes within 11p15 is thought to be coordinately regulated via the imprinted expression of KCNQ1OT1, which encodes an untranslated RNA. In skin fibroblasts from five monozygotic twin pairs discordant for BWS, each affected twin had an imprinting defect at KCNQ1OT1 on 11p15, whereas the unaffected twin did not. Five additional monozygotic twin pairs, for whom only blood was available, also displayed an imprinting defect at KCNQ1OT1. It is possible that discordance for BWS in MZ twins is due to unequal splitting of the inner cell mass during twinning, thereby causing differential maintenance of imprinting at KCNQ1OT1. Alternatively, we propose that KCNQ1OT1 is especially vulnerable to a loss of imprinting event, caused by a lack of maintenance DNA methylation at a critical stage of preimplantation development, and that this loss of imprinting predisposes to twinning as well as to discordance for BWS. These data underscore the importance of continued surveillance of children born following assisted reproductive technologies that impact the preimplantation embryo.

Proteomic analysis of hair shafts from monozygotic twins: Expression profiles and genetically variant peptides.

PubMed

Wu, Pei-Wen; Mason, Katelyn E; Durbin-Johnson, Blythe P; Salemi, Michelle; Phinney, Brett S; Rocke, David M; Parker, Glendon J; Rice, Robert H

2017-07-01

Forensic association of hair shaft evidence with individuals is currently assessed by comparing mitochondrial DNA haplotypes of reference and casework samples, primarily for exclusionary purposes. Present work tests and validates more recent proteomic approaches to extract quantitative transcriptional and genetic information from hair samples of monozygotic twin pairs, which would be predicted to partition away from unrelated individuals if the datasets contain identifying information. Protein expression profiles and polymorphic, genetically variant hair peptides were generated from ten pairs of monozygotic twins. Profiling using the protein tryptic digests revealed that samples from identical twins had typically an order of magnitude fewer protein expression differences than unrelated individuals. The data did not indicate that the degree of difference within twin pairs increased with age. In parallel, data from the digests were used to detect genetically variant peptides that result from common nonsynonymous single nucleotide polymorphisms in genes expressed in the hair follicle. Compilation of the variants permitted sorting of the samples by hierarchical clustering, permitting accurate matching of twin pairs. The results demonstrate that genetic differences are detectable by proteomic methods and provide a framework for developing quantitative statistical estimates of personal identification that increase the value of hair shaft evidence. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Access to green space, physical activity and mental health: a twin study.

PubMed

Cohen-Cline, Hannah; Turkheimer, Eric; Duncan, Glen E

2015-06-01

Increasing global urbanisation has resulted in a greater proportion of the world's population becoming exposed to risk factors unique to urban areas, and understanding these effects on public health is essential. The aim of this study was to examine the association between access to green space and mental health among adult twin pairs. We used a multilevel random intercept model of same-sex twin pairs (4338 individuals) from the community-based University of Washington Twin Registry to analyse the association between access to green space, as measured by the Normalised Difference Vegetation Index and self-reported depression, stress, and anxiety. The main parameter of interest was the within-pair effect for identical (monozygotic, MZ) twins because it was not subject to confounding by genetic or shared childhood environment factors. Models were adjusted for income, physical activity, neighbourhood deprivation and population density. When treating twins as individuals and not as members of a twin pair, green space was significantly inversely associated with each mental health outcome. The association with depression remained significant in the within-pair MZ univariate and adjusted models; however, there was no within-pair MZ effect for stress or anxiety among the models adjusted for income and physical activity. These results suggest that greater access to green space is associated with less depression, but provide less evidence for effects on stress or anxiety. Understanding the mechanisms linking neighbourhood characteristics to mental health has important public health implications. Future studies should combine twin designs and longitudinal data to strengthen causal inference. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Ultrasound in twin pregnancies.

PubMed

Morin, Lucie; Lim, Kenneth

2011-06-01

To review the literature with respect to the use of diagnostic ultrasound in the management of twin pregnancies. To make recommendations for the best use of ultrasound in twin pregnancies. Reduction in perinatal mortality and morbidity and short- and long-term neonatal morbidity in twin pregnancies. Optimization of ultrasound use in twin pregnancies. Published literature was retrieved through searches of PubMed and the Cochrane Library in 2008 and 2009 using appropriate controlled vocabulary (e.g., twin, ultrasound, cervix, prematurity) and key words (e.g., acardiac, twin, reversed arterial perfusion, twin-to-twin transfusion syndrome, amniotic fluid). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date restrictions. Studies were restricted to those with available English or French abstracts or text. Searches were updated on a regular basis and incorporated into the guideline to September 2009. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. The evidence collected was reviewed by the Diagnostic Imaging Committee of the Society of Obstetricians and Gynaecologists of Canada, with input from members of the Maternal Fetal Medicine Committee and the Genetics Committee of the SOGC. The recommendations were made according to the guidelines developed by The Canadian Task Force on Preventive Health Care (Table 1). The benefit expected from this guideline is facilitation and optimization of the use of ultrasound in twin pregnancy. SUMMARY STATEMENTS: 1. There are insufficient data to make recommendations on repeat anatomical assessments in twin pregnancies. Therefore, a complete anatomical survey at each scan may not be needed following a complete

Regional cerebral blood flow changes in female to male gender identity disorder.

PubMed

Nawata, Hideyuki; Ogomori, Koji; Tanaka, Mariko; Nishimura, Ryoji; Urashima, Hajime; Yano, Rika; Takano, Koichi; Kuwabara, Yasuo

2010-04-01

Despite a range of research on gender identity disorder (GID), at present there is no scientific consensus on whether the etiology of GID is mental or physical. In particular recent advances in the technology of neuroimaging research have led to an increased understanding of the biological basis of various mental disorders. GID also should be evaluated from this perspective. The aim of the present study was therefore to do the first trial to examine the regional cerebral blood flow (rCBF) in GID. Persons considered biologically male fulfilling the GID criteria are termed male to female (MTF) and, conversely, persons considered biological female are termed female to male (FTM). We compared 11 FTM subjects and nine age- and handedness-matched female control subjects. None of the subjects was regularly taking medication and none had any kind of physical or psychiatric comorbidity. To evaluate rCBF in GID subjects and control subjects, statistical parametric mapping analysis of (99m)Tc-ethyl-cysteinate dimer single-photon emission computed tomography was used. GID subjects had a significant decrease in rCBF in the left anterior cingulate cortex (ACC) and a significant increase in the right insula compared to control subjects. The ACC and insula are regions that have been noted as being related to human sexual behavior and consciousness. From these findings, useful insights into the biological basis of GID were suggested.

Sports pairs: insights on athletic talent; research reviews: twins with leukemia; parents and twins.

PubMed

Segal, Nancy L

2007-06-01

Twin research exploring genetic and environmental influences on athletic interests and talents is reviewed. Illustrative examples of twin athletes representing a variety of sports activities are presented. This is followed by an overview of twin studies offering critical insights into the onset and progress of leukemia. In the last section, timely events involving twins and parents of twins will be described--each case provides a new look at an old question.

The Brazilian Twin Registry.

PubMed

Ferreira, Paulo H; Oliveira, Vinicius C; Junqueira, Daniela R; Cisneros, Lígia C; Ferreira, Lucas C; Murphy, Kate; Ordoñana, Juan R; Hopper, John L; Teixeira-Salmela, Luci F

2016-12-01

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. The collaboration includes the Federal University of Minas Gerais (UFMG) in Brazil, the University of Sydney and University of Melbourne in Australia, the Australian Twin Registry, as well as the research foundations CNPq and CAPES in Brazil. The BTR is a member of the International Network of Twin Registries. Recruitment strategies used to register twins have been through participation in a longitudinal study investigating genetic and environmental factors for low back pain occurrence, and from a variety of sources including media campaigns and social networking. Currently, 291 twins are registered in the BTR, with data on demographics, zygosity, anthropometrics, and health history having been collected from 151 twins using a standardized self-reported questionnaire. Future BTR plans include the registration of thousands of Brazilian twins identified from different sources and collaborate nationally and internationally with other research groups interested on twin studies.

Twin Loss: Implications for Counselors Working with Surviving Twins.(practice & Theory)

ERIC Educational Resources Information Center

Withrow, Rebecca; Schwiebert, Valerie L.

2005-01-01

Multiple births are becoming increasingly prevalent due to the use of fertility drugs and women choosing to wait until later life to conceive. With the growth in the twin population, little research has been done to investigate the effects on the grief process when 1 twin dies. Counselors must understand the unique experience of twins to formulate…

An examination of environmental and genetic contributions to the determinants of suicidal behavior among male twins

PubMed Central

Smith, April Rose; Ribeiro, Jessica; Mikolajewski, Amy; Taylor, Jeanette; Joiner, Thomas; Iacono, William G.

2012-01-01

The purpose of the present study was to examine the relative association of genetic and environmental factors with individual differences in each of the proximal, jointly necessary, and sufficient causes for suicidal behavior, according to the Interpersonal-Psychological Theory of Suicide (IPTS; Joiner, 2005). We examined data on derived scales measuring acquired capability, belongingness, and burdensomeness (the determinants of suicidal behavior, according to theory) from 348 adolescent male twins. Univariate biometrical models were used to estimate the magnitude of additive genetic (A), non-additive genetic (D), shared environmental (C), and nonshared environmental (E) effects associated with the variance in acquired capability, belongingness, and burdensomeness. The best fitting model for the acquired capability allowed for additive genetic and environmental effects, whereas the best fitting model for burdensomeness and belongingness allowed for shared and nonshared environmental effects. The present research extends prior work by specifying the environmental and genetic contributions to the components of the IPTS, and our findings suggest that belongingness and burdensomeness may be more appropriate targets for clinical intervention than acquired capability as these factors may be more malleable or amenable to change. PMID:22417928

The etiology of mathematical and reading (dis)ability covariation in a sample of Dutch twins.

PubMed

Markowitz, Ezra M; Willemsen, Gonneke; Trumbetta, Susan L; van Beijsterveldt, Toos C E M; Boomsma, Dorret I

2005-12-01

The genetic etiology of mathematical and reading (dis)ability has been studied in a number of distinct samples, but the true nature of the relationship between the two remains unclear. Data from the Netherlands Twin Register was used to determine the etiology of the relationship between mathematical and reading (dis)ability in adolescent twins. Ratings of mathematical and reading problems were obtained from parents of over 1500 twin pairs. Results of bivariate structural equation modeling showed a genetic correlation around .60, which explained over 90% of the phenotypic correlation between mathematical and reading ability. The genetic model was the same for males and females.

Interface structures and twinning mechanisms of {1¯012} twins in hexagonal metals

DOE PAGES

Gong, Mingyu; Hirth, John P.; Liu, Yue; ...

2017-06-07

In this paper, a controversy concerning the description of {1¯012} {1¯012} twinning, whether it is shear-shuffle or pure glide-shuffle or pure shuffle, has developed. There is disagreement about the interpretation of transmission electron microscopic observations, atomistic simulations and theories for twin growth. In this article, we highlight the atomic-level, characteristic, equilibrium and non-equilibrium boundaries and corresponding boundary defects associated with the three-dimensional ‘normal’, ‘forward’ and ‘lateral’ propagation of {1¯011} growth/annealing and deformation twins. Although deformation twin boundaries (TBs) after recovery exhibit some similarity to growth/annealing TBs because of the plastic accommodation of stress fields, there are important distinctions among them.more » These distinctions distinguish among the mechanisms of twin growth and resolve the controversy. In addition, a new type of disconnection, a glide disclination, is described for twinning. Synchroshear, seldom considered, is shown to be a likely mechanism for {1¯012} twinning.« less

Twins Eye Study in Tasmania (TEST): Rationale and Methodology to Recruit and Examine Twins

PubMed Central

Mackey, David A; MacKinnon, Jane R; Brown, Shayne A; Kearns, Lisa S; Ruddle, Jonathan B; Sanfilippo, Paul G; Sun, Cong; Hammond, Christopher J; Young, Terri L; Martin, Nicholas G; Hewitt, Alex W

2013-01-01

Visual impairment is a leading cause for morbidity and poor quality of life in our community. Unravelling the mechanisms underpinning important blinding diseases could allow for preventative or curative steps to be implemented. Twin siblings provide a unique opportunity in biology to discover genes associated with numerous eye diseases and ocular biometry. Twins are particularly useful for quantitative trait analysis through genome-wide association and linkage studies. Although many studies involving twins rely on twin registries, we present our approach to the Twins Eye Study in Tasmania to provide insight into possible recruitment strategies, expected participation rates and potential examination strategies that can be considered by other researchers for similar studies. Five separate avenues for cohort recruitment were adopted: 1) piggy-backing existing studies where twins had been recruited; 2); utilising the national twin registry; 3) word of mouth and local media publicity; 4) directly approaching schools; and finally 5) collaborating with other research groups studying twins. PMID:19803772

The Italian Twin Project: from the personal identification number to a national twin registry.

PubMed

Stazi, Maria Antonietta; Cotichini, Rodolfo; Patriarca, Valeria; Brescianini, Sonia; Fagnani, Corrado; D'Ippolito, Cristina; Cannoni, Stefania; Ristori, Giovanni; Salvetti, Marco

2002-10-01

The unique opportunity given by the "fiscal code", an alphanumeric identification with demographic information on any single person residing in Italy, introduced in 1976 by the Ministry of Finance, allowed a database of all potential Italian twins to be created. This database contains up to now name, surname, date and place of birth and home address of about 1,300,000 "possible twins". Even though we estimated an excess of 40% of pseudo-twins, this still is the world's largest twin population ever collected. The database of possible twins is currently used in population-based studies on multiple sclerosis, Alzheimer's disease, celiac disease, and type 1 diabetes. A system is currently being developed for linking the database with data from mortality and cancer registries. In 2001, the Italian Government, through the Ministry of Health, financed a broad national research program on twin studies, including the establishment of a national twin registry. Among all the possible twins, a sample of 500,000 individuals are going to be contacted and we expect to enrol around 120,000 real twin pairs in a formal Twin Registry. According to available financial resources, a sub sample of the enrolled population will be asked to donate DNA. A biological bank from twins will be then implemented, guaranteeing information on future etiological questions regarding genetic and modifiable factors for physical impairment and disability, cancers, cardiovascular diseases and other age related chronic illnesses.

Exploring Genetic and Environmental Effects in Dysphonia: A Twin Study

ERIC Educational Resources Information Center

Simberg, Susanna; Santtila, Pekka; Soveri, Anna; Varjonen, Markus; Sala, Eeva; Sandnabba, N. Kenneth

2009-01-01

Purpose: To explore the existence of genetic effects as well as the interaction between potential genetic effects and a voice-demanding occupation on dysphonia. Method: One thousand seven hundred and twenty-eight Finnish twins (555 male; 1,173 female) born between 1961 and 1989 completed a questionnaire concerning vocal symptoms and occupation.…

Needle twins and right-angled twins in minerals: comparison between experiment and theory

USGS Publications Warehouse

Salje, E.K.H.; Buckley, A.; Van Tendeloo, G.; Ishibashi, Y.; Nord, G.L.

1998-01-01

Transformation twinning in minerals forms isolated twin walls, intesecting walls with corner junctions, and wedge-shaped twins as elements of hierarchical patterns. When cut perpendicular to the twin walls, the twins have characteristic shapes, right-angled and needle-shaped wall traces, which can be observed by transmission electron microscopy or by optical microscopy. Theoretical geometries of wall shapes recently derived for strain-related systems should hold for most displacive and order-disorder type phase transitions: 1) right-angled twins show curved junctions; 2) needle-shaped twins contain flat wall segments near the needle tip if the elastic behaviour of the mineral is dominated by its anisotroyp; 3) additional bending forces and pinning effects lead to curved walls near the junction that make the needle tip appear more blunt. Bent right-angled twins were analyzed in Gd2(MoO4)3. Linear needle tips were found in WO3, [N(CH3)4]2.ZnBr4 CrAl, BiVO4, GdBa2Cu3O7, and PbZrO. Parabolic tips occur in K2Ba(NO2)4, and GeTe whereas exponential curvatures appear in BaTiO3, KSCN, Pb3(PO4)2, CaTiO3, alkali feldspars, YBa2Cu3O7, and MnAl. The size and shape of the twin microstructure relates to its formation during the phase transition and the subsequent annealing history. The mobility of the twin walls after formation depends not only on the thermal activation but also on the structure of the wall, which may be pinned to impurities on a favorable structural site. Depinnign energies are often large compared with thermal energies for diffusion. This leads to kinetic time scales for twin coarsening that are comparable to geological time scales. Therefore, transformation twins that exhibit needle domains not only indicate that the mineral underwent a structural phase transition but also contain information about its subsequent geological history.

Twin births in the Comoros.

PubMed

Abdul, M A

2000-11-01

To determine the prevalence and clinical significance of twin births in the Comoros Islands. Combined retrospective and non-randomised prospective study. Hospital El-Ma'aru Moroni Grand-Comoros and Center Medico-Chirurgical Domoni-Anjouan. One hundred and nine patients with twin deliveries. During the period of study, there were 4370 deliveries, out of which 109 were twin births, giving an incidence rate of 25/1,000 deliveries. Twin births rate increased with increasing parity. The perinatal mortality rate of twin delivery was seven times that of singleton. Low birthweight rate was 54% among twin births. Retention rate of second twin was 12%, with home delivery of the first co-twin in 62% of cases. Uterine atony and malpresentation were the principal factors in the aetiology of retained second twin. Multiple pregnancy is common in the Comoros and the epidemiology and clinical significance are consistent with established data. Clinicians and midwives in Comoros must be aware of these facts, and endeavour to make early diagnosis and institute appropriate management within the available scarce resources, in order to improve maternal and foetal outcome of twin births.

Influence of acquired obesity on coronary vessel wall late gadolinium enhancement in discordant monozygote twins.

PubMed

Makowski, Marcus R; Jansen, Christian H P; Ebersberger, Ullrich; Schaeffter, Tobias; Razavi, Reza; Mangino, Massimo; Spector, Tim D; Botnar, Rene M; Greil, Gerald F

2017-11-01

The aim of this study was to investigate the impact of BMI on late gadolinium enhancement (LGE) of the coronary artery wall in identical monozygous twins discordant for BMI. Coronary LGE represents a useful parameter for the detection and quantification of atherosclerotic coronary vessel wall disease. Thirteen monozygote female twin pairs (n = 26) with significantly different BMIs (>1.6 kg/m2) were recruited out of >10,000 twin pairs (TwinsUK Registry). A coronary 3D-T2prep-TFE MR angiogram and 3D-IR-TFE vessel wall scan were performed prior to and following the administration of 0.2 mmol/kg of Gd-DTPA on a 1.5 T MR scanner. The number of enhancing coronary segments and contrast to noise ratios (CNRs) of the coronary wall were quantified. An increase in BMI was associated with an increased number of enhancing coronary segments (5.3 ± 1.5 vs. 3.5 ± 1.6, p < 0.0001) and increased coronary wall enhancement (6.1 ± 1.1 vs. 4.8 ± 0.9, p = 0.0027) compared to matched twins with lower BMI. This study in monozygous twins indicates that acquired factors predisposing to obesity, including lifestyle and environmental factors, result in increased LGE of the coronary arteries, potentially reflecting an increase in coronary atherosclerosis in this female study population. • BMI-discordant twins allow the investigation of the influence of lifestyle factors independent from genetic confounders. • Only thirteen obesity-discordant twins were identified underlining the strong genetic component of BMI. • In female twins, a BMI increase is associated with increased coronary late gadolinium enhancement. • Increased late gadolinium enhancement in the coronary vessel wall potentially reflects increased atherosclerosis.

Impact of Sexual Orientation Identity on Medical Morbidities in Male-to-Female Transgender Patients.

PubMed

Gaither, Thomas W; Awad, Mohannad A; Osterberg, E Charles; Romero, Angelita; Bowers, Marci L; Breyer, Benjamin N

2017-02-01

We aim to describe the relationship between sexual orientation identity and medical morbidities in a large sample of male-to-female (MTF) transgender patients. We reviewed medical records of patients presenting for MTF sex reassignment surgery (SRS) by a single, high-volume surgeon from 2011 to 2015. Sexual attraction to men (heterosexual), women (lesbian), or both (bisexual) was asked of each patient. We examined 16 medical morbidities for this analysis. During the study period, 330 MTF transgender patients presented for SRS. The average age at the time of surgery was 38.9 (range 18-76). One hundred and one patients (32%) reported being heterosexual, 110 patients (34%) reported being lesbian, and 108 patients (34%) reported being bisexual. Lesbian patients presented for SRS at older ages (mean = 43 years old) compared with heterosexual patients (mean = 36 years old) and bisexual patients (mean = 37), P < 0.01. No differences were found in the majority of coexisting medical morbidities by sexual orientation identity. Lesbian patients had greater odds of having a history of depression, age-adjusted odds ratio (aOR) = 2.36, 95% confidence interval (CI) 1.26-4.40, compared with heterosexual patients. Lesbian patients had higher odds of being married or partnered, aOR = 2.31, 95% CI (1.27-4.19), compared with heterosexual patients. Heterosexual patients had higher odds of having human immunodeficiency virus (HIV), aOR = 9.07, 95% CI (1.08-76.5) compared with lesbian patients. Sexual orientation identity in MTF transgender patients is variable. The majority of medical morbidities are not associated with sexual orientation identity. Although HIV and depression are common morbidities among MTF patients seeking SRS, the prevalence of these morbidities differs by sexual orientation identity, but these findings need replication. Counseling and future research initiatives in transgender care should incorporate sexual orientation identity and

[Hereditary phaeochromocytoma in twins].

PubMed

Tóth, Géza; Patócs, Attila; Tóth, Miklós

2016-08-01

Phaeochromocytoma is a tumor of the catecholamine-producing cells of the adrenal gland. Extraadrenal phaeochromocytomas are frequently called paragangliomas. The majority of phaeochromocytomas are sporadic, however, about 25-30% are caused by genetic mutation. These tumor are frequently referred as hereditary phaeochromocytomas/paragangliomas. Their incidence increases continuously which can be attributed to availability of genetic examination and to the discovery of novel genes. The 47-year-old female patient underwent abdominal computed tomography which revealed bilateral adrenal gland enlargement. Abdominal magnetic resonance imaging, the 131-I- metaiodobenzylguanidine scintigraphy, urinary catecholamines and serum chomogranin A measurements confirmed the diagnosis of bilateral phaeochromocytomas. The genetically identical twin sister of the patient was also diagnosed with hormonally active bilateral phaechromocytoma, suggesting the genetic origin of phaeochromocytoma. Mutation screening confirmed a germline mutation of the transmembrane protein 127 tumorsupressor gene in both patients. Both patients underwent cortical-sparing adrenalectomy. The adrenal gland with the larger tumor was totally resected, while in the opposite side only the tumor was resected and a small part of the cortex was saved. After the operation urinary catecholamines and serum chromogranin A returned to normal in both patients. Adrenocortical deficiency was absent in the first patient, but her sister developed adrenal insufficiency requiring glucocorticoid replacement. To the best of the authors' knowledge phaeochromocytoma affecting twins has never been described earlier. Genetic examination performed in siblings confirmed the presence of the mutant gene through four generations. Orv. Hetil., 2016, 157(33), 1326-1330.

CoSMoS and TwinPaW: initial report on two new German twin studies.

PubMed

Spinath, Frank M; Wolf, Heike

2006-12-01

After briefly recapitulating two earlier German twin studies (BiLSAT and GOSAT), we present two new German twin studies with a longitudinal perspective: CoSMoS and TwinPaW. The twin study on Cognitive ability, Self-reported Motivation and School performance (CoSMoS) aims to investigate predictors and influences of school performance in a genetically sensitive design, beginning with children in late elementary school. The Twin study on Personality And Wellbeing (TwinPaW) focuses on adult personality and its relation to physical health as well as health-related behavior in an adult sample of twins. Both studies are characterized by an effort to recruit new large twin samples through a novel recruitment procedure aimed at reducing self-selective sampling. In two German federal states, contact information on persons born on the same day and with the same name was retrieved from record sections. From the resulting pool of more than 36,000 addresses we contacted approximately 2000 parents of twins aged 9 and 10 for CoSMoS, as well as 2000 adult twin pairs for TwinPaW by telephone and mail. Personal contact by telephone proved to be more efficient with agreement rates of 63% in the children sample and 65% in the adult sample. In this article we briefly describe the rationale and the study aims of CoSMoS and TwinPaW as well as the characteristics of the sample we have recruited so far.

The association between sports participation and athletic identity with eating pathology among college-aged males and females.

PubMed

Fay, K; Economos, C; Lerner, R M; Becker, A E; Sacheck, J

2011-06-01

The current study examined associations among sports participation (SP), athletic identity (AI), weight status, and eating pathology, and whether these relations differed by gender. Data come from male and female first-year college students who participated in the Tufts Longitudinal Health Study (TLHS) between 1999-2007 (N=712). Relations among SP, AI, actual and perceived weight statuses, Eating Disorders Inventory (EDI) subscale scores, and indices of body shape concern and restrictive eating were examined with hierarchical ordinary least squares (OLS) regression. Associations between SP and eating pathology among females were moderated by perceived weight status. By contrast, relations between males' EDI subscales scores and SP were moderated by ethnicity, as well as by actual weight status. Our findings support that sports participation alone neither promotes nor protects against eating pathology among males and females.

Use of a twin dataset to identify AMD-related visual patterns controlled by genetic factors

NASA Astrophysics Data System (ADS)

Quellec, Gwénolé; Abràmoff, Michael D.; Russell, Stephen R.

2010-03-01

The mapping of genotype to the phenotype of age-related macular degeneration (AMD) is expected to improve the diagnosis and treatment of the disease in a near future. In this study, we focused on the first step to discover this mapping: we identified visual patterns related to AMD which seem to be controlled by genetic factors, without explicitly relating them to the genes. For this purpose, we used a dataset of eye fundus photographs from 74 twin pairs, either monozygotic twins, who have the same genotype, or dizygotic twins, whose genes responsible for AMD are less likely to be identical. If we are able to differentiate monozygotic twins from dizygotic twins, based on a given visual pattern, then this pattern is likely to be controlled by genetic factors. The main visible consequence of AMD is the apparition of drusen between the retinal pigment epithelium and Bruch's membrane. We developed two automated drusen detectors based on the wavelet transform: a shape-based detector for hard drusen, and a texture- and color- based detector for soft drusen. Forty visual features were evaluated at the location of the automatically detected drusen. These features characterize the texture, the shape, the color, the spatial distribution, or the amount of drusen. A distance measure between twin pairs was defined for each visual feature; a smaller distance should be measured between monozygotic twins for visual features controlled by genetic factors. The predictions of several visual features (75.7% accuracy) are comparable or better than the predictions of human experts.

Inheritance of dermatoglyphic asymmetry and diversity traits in twins based on factor: variance decomposition analysis.

PubMed

Karmakar, Bibha; Malkin, Ida; Kobyliansky, Eugene

2013-06-01

Dermatoglyphic asymmetry and diversity traits from a large number of twins (MZ and DZ) were analyzed based on principal factors to evaluate genetic effects and common familial environmental influences on twin data by the use of maximum likelihood-based Variance decomposition analysis. Sample consists of monozygotic (MZ) twins of two sexes (102 male pairs and 138 female pairs) and 120 pairs of dizygotic (DZ) female twins. All asymmetry (DA and FA) and diversity of dermatoglyphic traits were clearly separated into factors. These are perfectly corroborated with the earlier studies in different ethnic populations, which indicate a common biological validity perhaps exists of the underlying component structures of dermatoglyphic characters. Our heritability result in twins clearly showed that DA_F2 is inherited mostly in dominant type (28.0%) and FA_F1 is additive (60.7%), but no significant difference in sexes was observed for these factors. Inheritance is also very prominent in diversity Factor 1, which is exactly corroborated with our previous findings. The present results are similar with the earlier results of finger ridge count diversity in twin data, which suggested that finger ridge count diversity is under genetic control.

Does the non-identity problem block a class of arguments against cloning?

PubMed

Green, Richard

2004-01-01

One class of argument against cloning human beings in the contemporary literature focuses on the bad consequences that will befall the clone or "later-twin." In this paper I consider whether this line of argumentation can be blocked by invoking Parfit's non-identity problem. I canvass two general strategies for solving the non-identity problem: a consequentialist strategy and non-consequentialist, rights based strategy. I argue that while each general strategy offers a plausible solution to the non-identity problem as applied to the cases most frequently discussed in the non-identity problem literature, neither provides a reason for putting aside the non-identity problem when applied to cloning. I conclude (roughly) that the non-identity problem does serve to block this class of argument against cloning.

Ventricular strain changes in monochorionic twins with and without twin-to-twin transfusion syndrome.

PubMed

Taylor-Clarke, Marisa C; Matsui, Hikoro; Roughton, Michael; Wimalasundera, Ruwan C; Gardiner, Helena M

2013-06-01

The objective of the study was to investigate whether vector velocity imaging (VVI), a non-Doppler speckle tracking ultrasound technology, is feasible in twin pregnancies and can aid management of twin-twin transfusion syndrome (TTTS). Twenty-seven women pregnant with monochorionic diamniotic twins affected by TTTS and 28 monochorionic pregnancies that did not develop TTTS were included in a prospective case-control study at a fetal medicine center. Fetal echocardiograms were recorded with dummy electrocardiography to retain original frame rates when exported for offline speckle tracking analysis using Syngo-VVI software (Siemens Corp, Munich, Germany). Right and left ventricular (LV) free wall Lagrangian strain was measured from the original coordinates. Within-twin pair ventricular strain differences including relationship to Quintero staging and response to laser therapy for TTTS were analyzed by Wilcoxon signed-rank test. The VVI strain measurements could be analyzed in 182 of 200 TTTS and 96 of 112 non-TTTS control ventricles. Within-pair strain was concordant in non-TTTS controls. Recipient LV strain was reduced at all Quintero stages compared with donors (P < .01). Recipient right ventricular strain was reduced only in stages 3 and 4 (P < .01). Strain improved at a median of 2 weeks following successful laser therapy. Intertwin differences in strain were independent of weight discordance. Recipient LV strain is reduced in stages 1 and 2 TTTS. Within-pair strain discordance may distinguish early TTTS from growth discordance and guide timing of and management following treatment. Copyright © 2013 Mosby, Inc. All rights reserved.

Effects of Light-Emitting Diode Therapy on Muscle Hypertrophy, Gene Expression, Performance, Damage, and Delayed-Onset Muscle Soreness: Case-control Study with a Pair of Identical Twins.

PubMed

Ferraresi, Cleber; Bertucci, Danilo; Schiavinato, Josiane; Reiff, Rodrigo; Araújo, Amélia; Panepucci, Rodrigo; Matheucci, Euclides; Cunha, Anderson Ferreira; Arakelian, Vivian Maria; Hamblin, Michael R; Parizotto, Nivaldo; Bagnato, Vanderlei

2016-10-01

The aim of this study was to verify how a pair of monozygotic twins would respond to light-emitting diode therapy (LEDT) or placebo combined with a strength-training program during 12 weeks. This case-control study enrolled a pair of male monozygotic twins, allocated randomly to LEDT or placebo therapies. Light-emitting diode therapy or placebo was applied from a flexible light-emitting diode array (λ = 850 nm, total energy = 75 J, t = 15 seconds) to both quadriceps femoris muscles of each twin immediately after each strength training session (3 times/wk for 12 weeks) consisting of leg press and leg extension exercises with load of 80% and 50% of the 1-repetition maximum test, respectively. Muscle biopsies, magnetic resonance imaging, maximal load, and fatigue resistance tests were conducted before and after the training program to assess gene expression, muscle hypertrophy and performance, respectively. Creatine kinase levels in blood and visual analog scale assessed muscle damage and delayed-onset muscle soreness, respectively, during the training program. Compared with placebo, LEDT increased the maximal load in exercise and reduced fatigue, creatine kinase, and visual analog scale. Gene expression analyses showed decreases in markers of inflammation (interleukin 1β) and muscle atrophy (myostatin) with LEDT. Protein synthesis (mammalian target of rapamycin) and oxidative stress defense (SOD2 [mitochondrial superoxide dismutase]) were up-regulated with LEDT, together with increases in thigh muscle hypertrophy. Light-emitting diode therapy can be useful to reduce muscle damage, pain, and atrophy, as well as to increase muscle mass, recovery, and athletic performance in rehabilitation programs and sports medicine.

Myeloproliferative Neoplasms in Danish Twins.

PubMed

Andersen, Michael Asger; Bjerrum, Ole Weis; Ranjan, Ajenthen; Skov, Vibe; Kruse, Torben A; Thomassen, Mads; Skytthe, Axel; Hasselbalch, Hans Carl; Christensen, Kaare

2018-01-01

Myeloproliferative neoplasms (MPNs) are a heterogeneous group of diseases characterized by clonal hyperproliferation of immature and mature cells of the myeloid lineage. Genetic differences have been proposed to play a role in the development of MPNs. Monozygotic twin pairs with MPNs have been reported in a few case reports, but the MPN concordance pattern in twins remains unknown. All twin pairs born in the period 1900-2010 were identified in the nationwide Danish Twin Registry. Only pairs with both twins alive on January 1, 1977, and those born thereafter were included to allow identification in the Danish National Patient Registry. A total of 158 twin pairs were registered with an MPN diagnosis: 36 monozygotic, 104 dizygotic, and 18 pairs with unknown zygosity. MPNs were diagnosed in both twins in 4 pairs. The probandwise concordance rates for monozygotic twin pairs were higher than for dizygotic twin pairs (15 vs. 0%; p = 0.016). An estimated concordance rate of 15% (95% CI 0.059-0.31) is modest, but given the rarity of MPNs this finding is clinically relevant and provides further support for the role of genetic predisposition in the development of MPNs. © 2018 S. Karger AG, Basel.

Balancing Fairness and Efficiency: The Impact of Identity-Blind and Identity-Conscious Accountability on Applicant Screening

PubMed Central

Self, William T.; Mitchell, Gregory; Mellers, Barbara A.; Tetlock, Philip E.; Hildreth, J. Angus D.

2015-01-01

This study compared two forms of accountability that can be used to promote diversity and fairness in personnel selections: identity-conscious accountability (holding decision makers accountable for which groups are selected) versus identity-blind accountability (holding decision makers accountable for making fair selections). In a simulated application screening process, undergraduate participants (majority female) sorted applicants under conditions of identity-conscious accountability, identity-blind accountability, or no accountability for an applicant pool in which white males either did or did not have a human capital advantage. Under identity-conscious accountability, participants exhibited pro-female and pro-minority bias, particularly in the white-male-advantage applicant pool. Under identity-blind accountability, participants exhibited no biases and candidate qualifications dominated interview recommendations. Participants exhibited greater resentment toward management under identity-conscious accountability. PMID:26660723

Creating a social world: a developmental twin study of peer-group deviance.

PubMed

Kendler, Kenneth S; Jacobson, Kristen C; Gardner, Charles O; Gillespie, Nathan; Aggen, Steven A; Prescott, Carol A

2007-08-01

Peer-group deviance is strongly associated with externalizing behaviors. We have limited knowledge of the sources of individual differences in peer-group deviance. To clarify genetic and environmental contributions to peer-group deviance in twins from midchildhood through early adulthood. Retrospective assessments using a life-history calendar. Analysis by biometric growth curves. General community. Members of male-male pairs from the population-based Virginia Twin Registry personally interviewed in 1998-2004 (n = 1802). Self-reported peer-group deviance at ages 8 to 11, 12 to 14, 15 to 17, 18 to 21, and 22 to 25 years. Mean and variance of peer-group deviance increased substantially with age. Genetic effects on peer-group deviance showed a strong and steady increase over time. Family environment generally declined in importance over time. Individual-specific environmental influences on peer-group deviance levels were stable in the first 3 age periods and then increased as most twins left home. When standardized, the heritability of peer-group deviance is approximately 30% at ages 8 to 11 years and rises to approximately 50% across the last 3 time periods. Both genes and shared environment contributed to individual differences in the developmental trajectory of peer-group deviance. However, while the correlation between childhood peer-group deviance levels and the subsequent slope of peer-group deviance over time resulting from genetic factors was positive, the same relationship resulting from shared environmental factors was negative. As male twins mature and create their own social worlds, genetic factors play an increasingly important role in their choice of peers, while shared environment becomes less influential. The individual-specific environment increases in importance when individuals leave home. Individuals who have deviant peers in childhood, as a result of genetic vs shared environmental influences, have distinct developmental trajectories

I. 'Street of twins': multiple births in Cuba II. The Cuban twin registry: an update / twin research reports: cord entanglement; heritability of clubfoot; school separation / twins and twin researchers in the news: reunited at seventy-eight; basketball duo dissolved; delivered holding hands; the better brew; award winners.

PubMed

Segal, Nancy L; Marcheco-Teruel, Beatriz

2014-08-01

I was part of a people-to-people tour of Havana, Cuba during the first week in April 2014. Among the many highlights of that adventure were an informal meeting with Dr Beatriz Marcheco-Teruel, from Cuba's National Center for Medical Genetics, and a visit to the famous 'Street of Twins'. A fortuitous meeting with parents of twins in the fishing town of Jaimanitas was also an extraordinary event. The Cuban experience is followed by summaries of recent twin research, covering umbilical cord entanglement, the heritability of clubfoot and school separation policies for twins. Media reports include twins reunited at age 78, the future of UCLA's twin basketball players, MZ twins born holding hands, a twin conflict over beer and a pair of American Psychological Association honors for Drs Nancy L. Segal and Thomas J. Bouchard, Jr.

Research from the NASA Twins Study and Omics in Support of Mars Missions

NASA Technical Reports Server (NTRS)

Kundrot, C.; Shelhamer, M.; Scott, G.

2015-01-01

The NASA Twins Study, NASA's first foray into integrated omic studies in humans, illustrates how an integrated omics approach can be brought to bear on the challenges to human health and performance on a Mars mission. The NASA Twins Study involves US Astronaut Scott Kelly and his identical twin brother, Mark Kelly, a retired US Astronaut. No other opportunity to study a twin pair for a prolonged period with one subject in space and one on the ground is available for the foreseeable future. A team of 10 principal investigators are conducting the Twins Study, examining a very broad range of biological functions including the genome, epigenome, transcriptome, proteome, metabolome, gut microbiome, immunological response to vaccinations, indicators of atherosclerosis, physiological fluid shifts, and cognition. A novel aspect of the study is the integrated study of molecular, physiological, cognitive, and microbiological properties. Major sample and data collection from both subjects for this study began approximately six months before Scott Kelly's one year mission on the ISS, continue while Scott Kelly is in flight and will conclude approximately six months after his return to Earth. Mark Kelly will remain on Earth during this study, in a lifestyle unconstrained by this study, thereby providing a measure of normal variation in the properties being studied. An overview of initial results and the future plans will be described as well as the technological and ethical issues raised for spaceflight studies involving omics.

Whole-genome scale identification of methylation markers specific for cerebral palsy in monozygotic discordant twins

PubMed Central

Jiao, Zhe; Jiang, Zhimei; Wang, Jingtao; Xu, Hui; Zhang, Qiang; Liu, Shuang; Du, Ning; Zhang, Yuanyuan; Qiu, Hongbin

2017-01-01

Cerebral palsy (CP) is a severe type of brain disease affecting movement and posture. Although CP has strong genetic and environmental components, considerable differences in the methylome between monozygotic (MZ) twins discordant for CP implicates epigenetic contributors as well. In order to determine the differences in methylation in patients with CP without interference of the interindividual genomic variation, four pairs of MZ twins discordant for CP were profiled for DNA methylation changes using reduced representation bisulfite sequencing on the genomic-scale. Similar DNA methylation patterns were observed in all samples. However, MZ twins demonstrated higher correlations and closer evolutionary associations compared with the other samples, indicating a stable methylome of MZ twins. A total of 190 differentially methylated genes (DMGs) were identified using Student's t-test, of which 37 genes were hypermethylated in the CP group while the remainders were hypomethylated compared with control group. The identified DMGs were enriched in several cerebral abnormalities, including cerebral cortical atrophy and cerebral atrophy, suggesting that the occurrence of CP may be associated with the methylation alterations. The neighboring genes of DMGs in the protein-protein interaction network were enriched in numerous important functions in essential processes. The results of the present study identified important genes that may epigenetically contribute to the occurrence and development of CP in MZ twins, suggesting that the different prevalence of CP in identical twins may be associated with DNA methylation alterations. PMID:29039597

Type 3 Thyroplasty for a Patient with Female-to-Male Gender Identity Disorder.

PubMed

Saito, Yu; Nakamura, Kazuhiro; Itani, Shigeto; Tsukahara, Kiyoaki

2018-01-01

In most cases, about the voice of the patient with female-to-male/gender identity disorder (FTM/GID), hormone therapy makes the voice low-pitched. In success cases, there is no need for phonosurgery. However, hormone therapy is not effective in some cases. We perform type 3 thyroplasty in these cases. Hormone therapy was started in 2008 but did not lower the speaking fundamental frequencies (SFFs). We therefore performed TP3 under local anesthesia. In our case, the SFF at the first visit was 146 Hz. The postoperative SFF was 110 Hz. TP3 was performed under local anesthesia in a patient with FTM/GID in whom hormone therapy proved ineffective. With successful conversion to a lower-pitched voice, the patient could begin to live daily life as a male. QOL improved significantly with TP3. If hormone therapy proves ineffective, TP3 may be selected as an optional treatment and appears to show few surgical complications and was, in this case, a very effective treatment.

Separation anxiety among birth-assigned male children in a specialty gender identity service.

PubMed

VanderLaan, Doug P; Santarossa, Alanna; Nabbijohn, A Natisha; Wood, Hayley; Owen-Anderson, Allison; Zucker, Kenneth J

2018-01-01

Previous research suggested that separation anxiety disorder (SAD) is overrepresented among birth-assigned male children clinic-referred for gender dysphoria (GD). The present study examined maternally reported separation anxiety of birth-assigned male children assessed in a specialty gender identity service (N = 360). SAD was determined in relation to DSM-III and DSM-IV criteria, respectively. A dimensional metric of separation anxiety was examined in relation to several additional factors: age, ethnicity, parental marital status and social class, IQ, gender nonconformity, behavioral and emotional problems, and poor peer relations. When defined in a liberal fashion, 55.8% were classified as having SAD. When using a more conservative criterion, 5.3% were classified as having SAD, which was significantly greater than the estimated general population prevalence for boys, but not for girls. Dimensionally, separation anxiety was associated with having parents who were not married or cohabitating as well as with elevations in gender nonconformity; however, the association with gender nonconformity was no longer significant when statistically controlling for internalizing problems. Thus, SAD appears to be common among birth-assigned males clinic-referred for GD when defined in a liberal fashion, and more common than in boys, but not girls, from the general population even when more stringent criteria were applied. Also, the degree of separation anxiety appears to be linked to generic risk factors (i.e., parental marital status, internalizing problems). As such, although separation anxiety is common among birth-assigned male children clinic-referred for GD, it seems unlikely to hold unique significance for this population based on the current data.

[Twins in myth (author's transl)].

PubMed

de Rachewiltz, B; Parisi, P; Castellani, V

1976-01-01

Twins have an important place in mythology and a sacred character appears to be attached to them since the most ancient times. In ancient Egypt, the royal placenta was worshipped, being considered as the Pharao's twin (a conception that is still alive among certain African populations), and actually everyone was considered to possess a spiritual twin, the Ka or astral body, through whom it was supposed to be possible to operate with magic rituals and hit enemies. Twin gods were worshipped by Babylonians and Assyrians (who even introduced them among astronomic constellations), and may be also found in the Persian and Veda religions. In the classic, Greco-Roman world, the examples of twin gods and heroes are innumerable: from the twin sons of Zeus, the Dioscuri, to the opposite-sexed twin gods Apollo and Diana, to Rome's founders, Romulus and Remus, etc. Since the most ancient times, a magic conception is connected to the twins, either in a positive or a negative sense, but often with some kind of a "fatidic" aspect. Such a two-faced approach to the phenomenon of twinning, that variously characterizes near-east, protomediterranean, classic, and other ancient civilizations, may still be found in contemporary primitive societies.

Cannabis and Depression: A Twin Model Approach to Co-morbidity.

PubMed

Smolkina, M; Morley, K I; Rijsdijk, F; Agrawal, A; Bergin, J E; Nelson, E C; Statham, D; Martin, N G; Lynskey, M T

2017-07-01

Cannabis use disorder (CUD) co-occurs with major depressive disorder (MDD) more frequently than would be expected by chance. However, studies to date have not produced a clear understanding of the mechanisms underlying this co-morbidity. Genetically informative studies can add valuable insight to this problem, as they allow the evaluation of competing models of co-morbidity. This study uses data from the Australian Twin Registry to compare 13 co-morbidity twin models initially proposed by Neale and Kendler (Am J Hum Genet 57:935-953, 1995). The analysis sample comprised 2410 male and female monozygotic and dizygotic twins (average age 32) who were assessed on CUD and MDD using the SSAGA-OZ interview. Data were analyzed in OpenMx. Of the 13 different co-morbidity models, two fit equally well: CUD causes MDD and Random Multiformity of CUD. Both fit substantially better than the Correlated Liabilities model. Although the current study cannot differentiate between them statistically, these models, in combination, suggest that CUD risk factors may causally influence the risk to develop MDD, but only when risk for CUD is high.

Cannabis Involvement and Nonsuicidal Self-Injury: A Discordant Twin Approach.

PubMed

Few, Lauren R; Grant, Julia D; Nelson, Elliot C; Trull, Timothy J; Grucza, Richard A; Bucholz, Kathleen K; Verweij, Karin J H; Martin, Nicholas G; Statham, Dixie J; Madden, Pamela A F; Heath, Andrew C; Lynskey, Michael T; Agrawal, Arpana

2016-11-01

Cannabis use, particularly at an early age, has been linked to suicidal thoughts and behavior, but minimal work has examined the association between cannabis use and lifetime nonsuicidal self-injury (NSSI). The current study aims to characterize the overlap between lifetime and early cannabis use and NSSI and to examine genetic and environmental mechanisms of this association. Adult male and female twins from the Australian Twin Registry (N = 9,583) were used to examine the odds of NSSI associated with lifetime cannabis use and early cannabis use (i.e., <17 years of age). These associations were also examined within monozygotic (MZ) twins discordant for cannabis use and MZ twins discordant for early cannabis use. Analyses were replicated in an independent sample of female twins (n = 3,787) accounting for the age at onset of cannabis use and NSSI. Lifetime cannabis use (odds ratio [OR] = 2.84, 95% CI [2.23, 3.61]) and early cannabis use were associated with increased odds of NSSI (OR = 2.15, 95% CI [1.75, 2.65]), and this association remained when accounting for covariates. The association was only significant, however, in MZ twin pairs discordant for early cannabis use (OR = 3.20, 95% CI [1.17, 8.73]). Replication analyses accounting for the temporal ordering of cannabis use and NSSI yielded similar findings of nominal significance. Results suggest that NSSI is associated with cannabis involvement via differing mechanisms. For lifetime cannabis use, the lack of association in discordant pairs suggests the role of shared genes and family environment. However, in addition to such shared familial influences, person-specific and putatively causal factors contribute to the relationship between early cannabis use and NSSI. Therefore, delaying the onset of cannabis use may reduce exposure to influences that exacerbate vulnerabilities to NSSI.

[Genetic and environmental contributions to body mass index in a Spanish adolescent twin sample].

PubMed

Iranzo-Tatay, Carmen; Gimeno-Clemente, Natalia; Livianos-Aldana, Lorenzo; Rojo-Moreno, Luis

2015-08-21

Twin and family studies support large genetic influences on variability in body mass index (BMI), with heritability estimates ranging from 47% to over 90%. Our objective was to study the relative contributions of genetics and environment to BMI, evaluating sex differences, in an adolescent twin sample from Valencia, Spain. Five hundred eighty-four pairs of adolescent twins between 13 and 18 years of age completed the study (82 monozygotic [MZ] and 87 dizygotic [DZ] pairs of male twins, 118 MZ and 102 DZ pairs of female twins, and 195 opposite-sex pairs of DZ twins). To determine zygosity, teachers responded a questionnaire on physical similarity. They also measured the participant's height and weight. BMI was calculated and weight status was determined according to age. We used twin models to assess genetic and environmental (common and unique) factors affecting BMI. There was a 7.1% frequency of overweight and 2.8% of obesity. The estimated heritability of BMI was 88.0% in boys and 72.1% in girls, with the remaining variance attributable to non-shared environment in boys (12.0%) and 8.8% in girls. It was only in girls that common environment had an effect on BMI. Genetics appears to play an important role in explaining the variability in BMI in the adolescence, with slight variations between boys and girls. Common environmental factors exert their influence on BMI only in girls. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

Dimensional profiles of male to female gender identity disorder: an exploratory research.

PubMed

Fisher, Alessandra D; Bandini, Elisa; Ricca, Valdo; Ferruccio, Naika; Corona, Giovanni; Meriggiola, Maria C; Jannini, Emmanuele A; Manieri, Chiara; Ristori, Jiska; Forti, Gianni; Mannucci, Edoardo; Maggi, Mario

2010-07-01

Male-to-Female Gender Identity Disorder (MtF GID) is a complex phenomenon that could be better evaluated by using a dimensional approach. To explore the aggregation of clinical manifestations of MtF GID in order to identify meaningful variables describing the heterogeneity of the disorder. A consecutive series of 80 MtF GID subjects (mean age 37 +/- 10.3 years), referred to the Interdepartmental Center for Assistance Gender Identity Disorder of Florence and to other Italian centers from July 2008 to June 2009, was studied. Diagnosis was based on formal psychiatric classification criteria. Factor analysis was performed. Several socio-demographic and clinical parameters were investigated. Patients were asked to complete the Bem Sex Role Inventory (BSRI, a self-rating scale to evaluate gender role) and Symptom Checklist-90 Revised (SCL-90-R, a self-rating scale to measure psychological state). Factor analysis identified two dimensional factors: Factor 1 was associated with sexual orientation, and Factor 2 related to behavioral and psychological correlates of early GID development. No correlation was observed between the two factors. A positive correlation between Factor 2 and feminine BSRI score was found, along with a negative correlation between Factor 2 and undifferentiated BSRI score. Moreover, a significant association between SCL-90-R Phobic subscale score and Factor 2 was observed. A variety of other socio-demographic parameters and clinical features were associated with both factors. Behavioral and psychological correlates of Factor 1 (sexual orientation) and Factor 2 (gender identity) do not constitute the framework of two separate clinical entities, but instead represent two dimensions of the complex MtF GID structure, which can be variably intertwined in the same subject. By using factor analysis, we offer a new approach capable of delineating a psychopathological and clinical profile of MtF GID patients.

Current management of male-to-female gender identity disorder in the UK.

PubMed

Tugnet, Nicola; Goddard, Jonathan Charles; Vickery, Richard M; Khoosal, Deenesh; Terry, Tim R

2007-10-01

Gender identity disorder (GID), or transsexualism as it is more commonly known, is a highly complex clinical entity. Although the exact aetiology of GID is unknown, several environmental, genetic and anatomical theories have been described. The diagnosis of GID can be a difficult process but is established currently using standards of care as defined by the Harry Benjamin International Gender Dysphoria Association. Patients go through extensive psychiatric assessment, including the Real Life Experience, which entails living in the desired gender role 24 h a day for a minimum period of 12 months. The majority of GID patients will eventually go on to have gender realignment surgery, which includes feminising genitoplasty. The clinical features, diagnostic approach and management of male-to-female GID in the UK are reviewed, including the behavioural, psychological and surgical aspects.

Birth weight by gestational age in twin pregnancies: analysis of 661 pairs.

PubMed

Hsieh, T T; Chen, C J; Hsu, J J

1992-02-01

The mortality of twin infants is four to five times higher than that of singletons, and one-half to two-thirds of all twins weigh < 2,500 g at birth. The appropriate interpretation of fetal growth throughout pregnancy is dependent upon the availability of adequate standards. We reviewed 661 pairs of live twin infants born at Chang Gung Memorial Hospital from 1979 to 1990. The frequency of twin births was 1.17% (1:86), and the ratio of males to females was 1.03. The frequency of preterm births (< 37 weeks) was 36.9%, the frequency of low birth weight (< 2,500 g) was 47.9% and very low birth weight (< 1,500 g) was 6.7%. A fetus grows most rapidly from the 32nd to the 35th week of gestation (200 g per week). The growth was 145 g per week from the 28th to the 32nd week and from the 35th to the 38th week of gestation. After the 38th week, the mean birth weight increased by only 35 g per week. Compared with a singleton birth, the mean birth weight of twins was about 100 g lighter during the 28th to the 32nd week, then the difference increased gradually to about 500 g at term.

A longitudinal investigation of the associations among parenting, deviant peer affiliation, and externalizing behaviors: a monozygotic twin differences design.

PubMed

Hou, Jinqin; Chen, Zhiyan; Natsuaki, Misaki N; Li, Xinying; Yang, Xiaodong; Zhang, Jie; Zhang, Jianxin

2013-06-01

Non-shared parenting and deviant peer affiliation are linked to differences in externalizing behaviors between twins. However, few studies have examined these two non-shared environments simultaneously. The present study examined the transactional roles of differential parenting (i.e., warmth and hostility) and deviant peer affiliation on monozygotic (MZ) twin differences in externalizing behaviors using a two-wave longitudinal study of twins and their parents. The sample consisted of 520 pairs of MZ twins (46.5% males, 53.5% females), with a mean age of 13.86 years (SD = 2.10) at the T1 assessment, residing in Beijing, China. The association between non-shared hostility in parenting and adolescent externalizing behaviors was mainly explained by a child-driven effect whereby the twin with a higher level of externalizing behaviors than his or her co-twin was more likely to receive more hostility from the parents. Similarly, the relationship between deviant peer affiliation and adolescent externalizing behaviors supported the selection effect whereby the twin with a higher level of externalizing behaviors than his or her co-twin was more likely to affiliate with deviant peers. The theoretical and practical implications of these findings are discussed.

Musculoskeletal disorders among female and male air traffic controllers performing identical and demanding computer work.

PubMed

Arvidsson, I; Arvidsson, M; Axmon, A; Hansson, G-A; Johansson, C R; Skerfving, S

2006-09-15

Operators with identical, demanding computer work (90 female and 97 male air traffic controllers) were found to have high prevalences of disorders (assessed by questionnaire and physical examination) in neck, shoulders and upper back. In spite of the identical work, the women displayed higher prevalences than the men (e.g. neck diagnoses 21% vs. 4%). Disorders in elbows, wrists and hands were less common, with similar rates in both genders. Generally, the psychosocial work environment (assessed by questionnaire) was found to be good, but with large inter-individual variation. Women experienced lower decision latitude than men, particularly regarding influence and freedom at work, but perceived higher social support. Physically, the work was characterized by relatively low angular velocities of upper arms (measured by inclinometry) and wrists (right: < 1 degrees/s during 19% of time, measuring by goniometry), dynamic muscular activities and high time fractions of rest in the trapezius and forearm extensor muscles (measuring by electromyography). There were only minor differences between the genders.

Attitudes to Gun Control in an American Twin Sample: Sex Differences in the Causes of Variation.

PubMed

Eaves, Lindon J; Silberg, Judy L

2017-10-01

The genetic and social causes of individual differences in attitudes to gun control are estimated in a sample of senior male and female twin pairs in the United States. Genetic and environmental parameters were estimated by weighted least squares applied to polychoric correlations for monozygotic (MZ) and dizygotic (DZ) twins of both sexes. The analysis suggests twin similarity for attitudes to gun control in men is entirely genetic while that in women is purely social. Although the volunteer sample is small, the analysis illustrates how the well-tested concepts and methods of genetic epidemiology may be a fertile resource for deepening our scientific understanding of biological and social pathways that affect individual risk to gun violence.

Twin-enhanced magnetic torque

NASA Astrophysics Data System (ADS)

Hobza, Anthony; García-Cervera, Carlos J.; Müllner, Peter

2018-07-01

Magnetic shape memory alloys experience magnetic-field-induced torque due to magnetocrystalline anisotropy and shape anisotropy. In a homogeneous magnetic field, torque results in bending of long samples. This study investigates the torque on a single crystal of Ni-Mn-Ga magnetic shape memory alloy constrained with respect to bending in an external magnetic field. The dependence of the torque on external magnetic field magnitude, strain, and twin boundary structure was studied experimentally and with computer simulations. With increasing magnetic field, the torque increased until it reached a maximum near 700 mT. Above 200 mT, the torque was not symmetric about the equilibrium orientation for a sample with one twin boundary. The torque on two specimen with equal strain but different twin boundary structures varied systematically with the spatial arrangement of crystallographic twins. Numerical simulations show that twin boundaries suppress the formation of 180° domains if the direction of easy magnetization between two twin boundaries is parallel to a free surface and the magnetic field is perpendicular to that surface. For a particular twin microstructure, the torque decreases with increasing strain by a factor of six due to the mutual compensation of magnetocrystalline and shape anisotropy. When free rotation is suppressed such as in transducers of magneto-mechanical actuators, magnetic-field-induced torque creates strong bending forces, which may cause friction and failure under cyclic loading.

Twinning in magnesium under dynamic loading

NASA Astrophysics Data System (ADS)

Dixit, Neha; Hazeli, Kavan; Ramesh, Kaliat T.

2015-09-01

Twinning is an important mode of deformation in magnesium (Mg) and its alloys at high strain rates. Twinning in this material leads to important effects such as mechanical anisotropy, texture evolution, tension-compression asymmetry, and sometimes non-Schmid effects. Extension twins in Mg can accommodate significant plastic deformation as they grow, and thus twinning affects the overall rate of plastic deformation. We use an experimental approach to study the deformation twinning mechanism under dynamic loading. We perform normal plate impact recovery experiments (with microsecond pulse durations) on pure polycrystalline Mg specimens. Estimates of average TB velocity under the known impact stress are obtained by characterization of twin sizes and aspect ratios developed within the target during the loading pulse. The measured average TB velocities in our experiments are of the order of several m s-1. These velocities are several orders of magnitude higher than those so far measured in Mg under quasi-static loading conditions. Electron back-scattered diffraction (EBSD) is then used to characterize the nature of the twins and the microstructural evolution. Detailed crystallographic analysis of the twins enables us to understand twin nucleation and growth of twin variants under dynamic loading.

Prenatal diagnosis of monocephalic bifacial tetraophthalmic diprosopus (conjoined twin).

PubMed

Dhaifalah, I; Curtisova, V; Santavy, J

2008-01-01

A case of diprosopus twinning which is rare conjoined twinning is reported prenatally at 22 weeks' gestation. 2D ultrasound examinations showed duplication of the craniofacial structures with four hemispheres, two cerebella and two thalami. There were three orbits two external ears, two noses, fused adjacent maxilla and two oral cavities with two fused oral opening and two jaws. The woman did not consent to any further investigations and the pregnancy was terminated. The postmortem examination confirmed the diagnosis in a male fetus with a crown-rump length of 155 mm, weighing 450 g. The body appeared normal except for a small poorly formed rudiment of a supernumerary digit next to the thumb of the right hand. The ultrasound examination and postmortem finding of this case is described with a short review of the literature. (c) 2007 S. Karger AG, Basel

Comparing Facial 3D Analysis With DNA Testing to Determine Zygosities of Twins.

PubMed

Vuollo, Ville; Sidlauskas, Mantas; Sidlauskas, Antanas; Harila, Virpi; Salomskiene, Loreta; Zhurov, Alexei; Holmström, Lasse; Pirttiniemi, Pertti; Heikkinen, Tuomo

2015-06-01

The aim of this study was to compare facial 3D analysis to DNA testing in twin zygosity determinations. Facial 3D images of 106 pairs of young adult Lithuanian twins were taken with a stereophotogrammetric device (3dMD, Atlanta, Georgia) and zygosity was determined according to similarity of facial form. Statistical pattern recognition methodology was used for classification. The results showed that in 75% to 90% of the cases, zygosity determinations were similar to DNA-based results. There were 81 different classification scenarios, including 3 groups, 3 features, 3 different scaling methods, and 3 threshold levels. It appeared that coincidence with 0.5 mm tolerance is the most suitable feature for classification. Also, leaving out scaling improves results in most cases. Scaling was expected to equalize the magnitude of differences and therefore lead to better recognition performance. Still, better classification features and a more effective scaling method or classification in different facial areas could further improve the results. In most of the cases, male pair zygosity recognition was at a higher level compared with females. Erroneously classified twin pairs appear to be obvious outliers in the sample. In particular, faces of young dizygotic (DZ) twins may be so similar that it is very hard to define a feature that would help classify the pair as DZ. Correspondingly, monozygotic (MZ) twins may have faces with quite different shapes. Such anomalous twin pairs are interesting exceptions, but they form a considerable portion in both zygosity groups.

Post-traumatic stress disorder and incidence of coronary heart disease: a twin study.

PubMed

Vaccarino, Viola; Goldberg, Jack; Rooks, Cherie; Shah, Amit J; Veledar, Emir; Faber, Tracy L; Votaw, John R; Forsberg, Christopher W; Bremner, J Douglas

2013-09-10

The aim of this study was to determine whether post-traumatic stress disorder (PTSD) is associated with coronary heart disease (CHD) using a prospective twin study design and objective measures of CHD. It has long been hypothesized that PTSD increases the risk of CHD, but empirical evidence using objective measures is limited. We conducted a prospective study of middle-aged male twins from the Vietnam Era Twin Registry. Among twin pairs without self-reported CHD at baseline, we selected pairs discordant for a lifetime history of PTSD, pairs discordant for a lifetime history of major depression, and pairs without either condition. All underwent a clinic visit after a median follow-up of 13 years. Outcomes included clinical events (myocardial infarction, other hospitalizations for CHD and coronary revascularization) and quantitative measures of myocardial perfusion by [(13)N] ammonia positron emission tomography, including a stress total severity score and coronary flow reserve. A total of 562 twins (281 pairs) with a mean age of 42.6 years at baseline were included in this study. The incidence of CHD was more than double in twins with PTSD (22.6%) than in those without PTSD (8.9%; p < 0.001). The association remained robust after adjusting for lifestyle factors, other risk factors for CHD, and major depression (odds ratio: 2.2; 95% confidence interval: 1.2 to 4.1). Stress total severity score was significantly higher (+95%, p = 0.001) and coronary flow reserve was lower (-0.21, p = 0.02) in twins with PTSD than in those without PTSD, denoting worse myocardial perfusion. Associations were only mildly attenuated in 117 twin pairs discordant for PTSD. Among Vietnam-era veterans, PTSD is a risk factor for CHD. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

[Research progress on molecular genetics of male homosexuality].

PubMed

Tu, Dan; Xu, Ruiwei; Zhao, Guanglu; Wang, Binbin; Feng, Tiejian

2016-08-01

Sexual orientation is influenced by both environmental factors and biological factors. Family and twin studies have shown that genetic factors play an important role in the formation of male homosexuality. Genome-wide scan also revealed candidate chromosomal regions which may be associated with male homosexuality, but so far no clearly related genes have been found. This article reviews the progress of relevant studies and candidate genes which are related to male homosexuality.

The utility of twins in developmental cognitive neuroscience research: How twins strengthen the ABCD research design.

PubMed

Iacono, William G; Heath, Andrew C; Hewitt, John K; Neale, Michael C; Banich, Marie T; Luciana, Monica M; Madden, Pamela A; Barch, Deanna M; Bjork, James M

2018-08-01

The ABCD twin study will elucidate the genetic and environmental contributions to a wide range of mental and physical health outcomes in children, including substance use, brain and behavioral development, and their interrelationship. Comparisons within and between monozygotic and dizygotic twin pairs, further powered by multiple assessments, provide information about genetic and environmental contributions to developmental associations, and enable stronger tests of causal hypotheses, than do comparisons involving unrelated children. Thus a sub-study of 800 pairs of same-sex twins was embedded within the overall Adolescent Brain and Cognitive Development (ABCD) design. The ABCD Twin Hub comprises four leading centers for twin research in Minnesota, Colorado, Virginia, and Missouri. Each site is enrolling 200 twin pairs, as well as singletons. The twins are recruited from registries of all twin births in each State during 2006-2008. Singletons at each site are recruited following the same school-based procedures as the rest of the ABCD study. This paper describes the background and rationale for the ABCD twin study, the ascertainment of twin pairs and implementation strategy at each site, and the details of the proposed analytic strategies to quantify genetic and environmental influences and test hypotheses critical to the aims of the ABCD study. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Status of sex reassignment surgery for gender identity disorder in Japan.

PubMed

Masumori, Naoya

2012-05-01

An incongruence between one's physiological sex and the gender identity that is one's basic sense of self as a man or a woman is known as gender identity disorder. In general, the conditions of physiological men having female gender identity and physiological women having male gender identity are called male-to-female and female-to-male gender identity disorder, respectively. Although the precise pathogenesis of gender identity disorder remains unclear, the prevalence of gender identity disorder is quite high, with the rates calculated for male-to-female to be 1:25,000 and female-to-male to be 1:12,000 in Hokkaido, Japan. The diagnosis and treatment of gender identity disorder in Japan are based on the Diagnostic and Therapeutic Guidelines for Patients with Gender Identity Disorder, 4th edition. Although gender identity disorder was previously thought to be a psychiatric condition, it is extremely difficult to assign gender identity to physiological sex by psychiatric and psychological treatments. To adapt the figure of the body to the native gender identity, physical treatments such as administration of cross-sex steroids and sex reassignment surgery are considered. However, there are very few institutions that routinely carry out sex reassignment surgery in Japan, even though it is mandatory for changing sex on the census register at the present time. Sex reassignment surgery for male-to-female and female-to-male patients includes orchiectomy, penectomy, clitoroplasty, vaginoplasty and vulvoplasty, and hysterectomy, ovariectomy, metoidioplasty and phalloplasty, respectively. To provide accurate information about physical treatment for patients with gender identity disorder, even urologists who are not actively involved in the diagnosis and treatment of gender identity disorder should understand the fundamental aspects and contemporary problems of gender identity disorder. © 2012 The Japanese Urological Association.

Epidemiological and clinical analysis of a consecutive series of conjoined twins in Spain.

PubMed

Martínez-Frías, María Luisa; Bermejo, Eva; Mendioroz, Jacobo; Rodríguez-Pinilla, Elvira; Blanco, Manuel; Egüés, Javier; Félix, Valentín; García, Angel; Huertas, Héctor; Nieto, Carmen; López, José Antonio; López, Santiago; Paisán, Luis; Rosa, Alejandro; Vázquez, María Socorro

2009-04-01

frequent type observed was thoracopagus, with an overall prevalence at birth of 0.44 per 100,000 (1/228,160) from 1980 to 2006, representing 58.82% of the total population of symmetric conjoined twin pairs. Diprosopus pairs were the next most common group (11.76%). Most of the cases were females (4 males/11 females), and although this appeared to be mainly because of the thoracopagus pairs (males-females, 2:8), in such a small number of cases, it is not possible to determine the ratios for the other groups. Gestational age was significantly shorter than in control twins for each type studied. We conclude that it is incorrect to consider that all types of conjoined twins have the same epidemiological characteristics, such as the frequency at birth. The differences observed may be related with the distinct embryo-fetal mortality of each type of conjoined twins in different populations, and the sex ratio, among others.

Genetic Correlates and Sex Differences in Holtzman Inkblot Technique Responses of Twins

ERIC Educational Resources Information Center

Rice, David G.; And Others

1976-01-01

Holtzman Inkblot Technique (HIT) responses of 36 same sex and 29 opposite sex college student twin pairs are analyzed. The results are discussed in terms of comparable genetic determination studies with Rorschach responses and the necessity for separate male and female norms on several HIT score response scales. (Author/DEP)

The Charles Perkins Centre's Twins Research Node.

PubMed

Ferreira, Lucas C; Craig, Jeffrey M; Hopper, John L; Carrick, Susan E

2016-08-01

Twins can help researchers disentangle the roles of genes from those of the environment on human traits, health, and diseases. To realize this potential, the Australian Twin Registry (ATR), University of Melbourne, and the Charles Perkins Centre (CPC), University of Sydney, established a collaboration to form the Twins Research Node, a highly interconnected research facility dedicated specifically to research involving twins. This collaboration aims to foster the adoption of twin designs as important tools for research in a range of health-related domains. The CPC hosted their Twins Research Node's launch seminar entitled 'Double the power of your research with twin studies', in which experienced twin researchers described how twin studies are supporting scientific discoveries and careers. The launch also featured twin pairs who have actively participated in research through the ATR. Researchers at the CPC were surveyed before the event to gauge their level of understanding and interest in utilizing twin research. This article describes the new Twins Research Node, discusses the survey's main results and reports on the launch seminar.

Genetic and environmental influences on sleep quality in middle-aged men: a twin study.

PubMed

Genderson, Margo R; Rana, Brinda K; Panizzon, Matthew S; Grant, Michael D; Toomey, Rosemary; Jacobson, Kristen C; Xian, Hong; Cronin-Golomb, Alice; Franz, Carol E; Kremen, William S; Lyons, Michael J

2013-10-01

Poor sleep quality is a risk factor for a number of cognitive and physiological age-related disorders. Identifying factors underlying sleep quality are important in understanding the etiology of these age-related health disorders. We investigated the extent to which genes and the environment contribute to subjective sleep quality in middle-aged male twins using the classical twin design. We used the Pittsburgh Sleep Quality Index to measure sleep quality in 1218 middle-aged twin men from the Vietnam Era Twin Study of Aging (mean age = 55.4 years; range 51-60; 339 monozygotic twin pairs, 257 dizygotic twin pairs, 26 unpaired twins). The mean PSQI global score was 5.6 [SD = 3.6; range 0-20]. Based on univariate twin models, 34% of variability in the global PSQI score was due to additive genetic effects (heritability) and 66% was attributed to individual-specific environmental factors. Common environment did not contribute to the variability. Similarly, the heritability of poor sleep-a dichotomous measure based on the cut-off of global PSQI>5-was 31%, with no contribution of the common environment. Heritability of six of the seven PSQI component scores (subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, and daytime dysfunction) ranged from 0.15 to 0.31, whereas no genetic influences contributed to the use of sleeping medication. Additive genetic influences contribute to approximately one-third of the variability of global subjective sleep quality. Our results in middle-aged men constitute a first step towards examination of the genetic relationship between sleep and other facets of aging. © 2013 European Sleep Research Society.

Genetic and Environmental Influences on Sleep Quality in Middle-Aged Men: A Twin Study

PubMed Central

Genderson, Margo R.; Rana, Brinda K.; Panizzon, Matthew S.; Grant, Michael D.; Toomey, Rosemary; Jacobson, Kristen C.; Xian, Hong; Cronin-Golomb, Alice; Franz, Carol E.; Kremen, William S.; Lyons, Michael J.

2013-01-01

SUMMARY Poor sleep quality is a risk factor for a number of cognitive and physiological age-related disorders. Identifying factors underlying sleep quality are important in understanding the etiology of these age-related health disorders. We investigated the extent to which genes and the environment contribute to subjective sleep quality in middle-aged male twins using the classical twin design. We used the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality in 1218 middle-aged twin men from the Vietnam Era Twin Study of Aging (VETSA)(mean age=55.4 years; range 51–60; 339 monozygotic twin pairs, 257 dizygotic twin pairs, 26 unpaired twins). The mean PSQI global score was 5.6 (SD=3.6; range 0–20). Based on univariate twin models, 34% of variability in the global PSQI score was due to additive genetic effects (heritability) and 66% was attributed to individual-specific environmental factors. Common environment did not contribute to the variability. Similarly, the heritability of poor sleep—a dichotomous measure based on the cut-off of global PSQI>5--was 31% with no contribution of the common environment. Heritability of six of the seven PSQI component scores (Subjective Sleep Quality, Sleep Latency, Sleep Duration, Habitual Sleep Efficiency, Sleep Disturbances, and Daytime Dysfunction) ranged from .15 to .31, where as no genetic influences contributed to Use of Sleeping Medication. Additive genetic influences contribute to approximately one-third of the variability of global subjective sleep quality. Our results in middle-aged men constitute a first step toward examination of the genetic relationship between sleep and other facets of aging. PMID:23509903

Growth curves for twins in Slovenia.

PubMed

Bricelj, Katja; Blickstein, Isaac; Bržan-Šimenc, Gabrijela; Janša, Vid; Lučovnik, Miha; Verdenik, Ivan; Trojner-Bregar, Andreja; Tul, Nataša

2017-02-01

Abnormalities of fetal growth are more common in twins. We introduce the growth curves for monitoring fetal growth in twin pregnancies in Slovenia. Slovenian National Perinatal Information System for the period between 2002 and 2010 was used to calculate birth weight percentiles for all live born twins for each week from 22nd to 40th week. The calculated percentiles of birth weight for all live-born twins in Slovenia served as the basis for drawing 'growth' curves. The calculated growth curves for twins will help accurately diagnose small or large twin fetuses for their gestational age in the native central European population.

Deformation twinning: Influence of strain rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gray, G.T. III

Twins in most crystal structures, including advanced materials such as intermetallics, form more readily as the temperature of deformation is decreased or the rate of deformation is increased. Both parameters lead to the suppression of thermally-activated dislocation processes which can result in stresses high enough to nucleate and grow deformation twins. Under high-strain rate or shock-loading/impact conditions deformation twinning is observed to be promoted even in high stacking fault energy FCC metals and alloys, composites, and ordered intermetallics which normally do not readily deform via twinning. Under such conditions and in particular under the extreme loading rates typical of shockmore » wave deformation the competition between slip and deformation twinning can be examined in detail. In this paper, examples of deformation twinning in the intermetallics TiAl, Ti-48Al-lV and Ni{sub 3}A as well in the cermet Al-B{sub 4}C as a function of strain rate will be presented. Discussion includes: (1) the microstructural and experimental variables influencing twin formation in these systems and twinning topics related to high-strain-rate loading, (2) the high velocity of twin formation, and (3) the influence of deformation twinning on the constitutive response of advanced materials.« less

Vascular twin nevi.

PubMed

Agirgol, Senay; Ozturk, Hatice Nur; Ozkok Akbulut, Tugba; Gunduzoglu, Ceyda; Koc, Leyli Kadriye; Turkoglu, Zafer

2017-04-27

Vascular twin nevi (VTN) are characterized by the simultaneous dermatological manifestatiton of a telangiectatic naevus close to a nevus anemicus. Nevus anemicus (NA) is a vascular anomaly characterized by localized pale patches with normal melanine and melanocyte level. According to twin spotting phenomenon crossing-over in heterozygous somatic-cells during mitosis results in two different offspring homozygous cells. Consequent to this mechanism, two different vascular anomalies may occur at the same region. We present a patient with VTN and NA combination which we think serves as an example for a rare twin spotting phenomenon in the literature. © 2017 Wiley Periodicals, Inc.

Some Features of Dialogue between Twins

ERIC Educational Resources Information Center

Savic, Svenka; Jocic, Mirjana

1975-01-01

Dialogues of sets of socially similar twins are studied. The opinion that twins have slower syntactic development than non-twins is seriously questioned. Dialogues with twins saying the same utterance together, correcting each other, quarreling, playing verbal games, etc. are analyzed in their deep structure. (SCC)

Epigenetic differences in monozygotic twins discordant for major depressive disorder

PubMed Central

Malki, K; Koritskaya, E; Harris, F; Bryson, K; Herbster, M; Tosto, M G

2016-01-01

Although monozygotic (MZ) twins share the majority of their genetic makeup, they can be phenotypically discordant on several traits and diseases. DNA methylation is an epigenetic mechanism that can be influenced by genetic, environmental and stochastic events and may have an important impact on individual variability. In this study we explored epigenetic differences in peripheral blood samples in three MZ twin studies on major depressive disorder (MDD). Epigenetic data for twin pairs were collected as part of a previous study using 8.1-K-CpG microarrays tagging DNA modification in white blood cells from MZ twins discordant for MDD. Data originated from three geographical regions: UK, Australia and the Netherlands. Ninety-seven MZ pairs (194 individuals) discordant for MDD were included. Different methods to address non independently-and-identically distributed (non-i.i.d.) data were evaluated. Machine-learning methods with feature selection centered on support vector machine and random forest were used to build a classifier to predict cases and controls based on epivariations. The most informative variants were mapped to genes and carried forward for network analysis. A mixture approach using principal component analysis (PCA) and Bayes methods allowed to combine the three studies and to leverage the increased predictive power provided by the larger sample. A machine-learning algorithm with feature reduction classified affected from non-affected twins above chance levels in an independent training-testing design. Network analysis revealed gene networks centered on the PPAR−γ (NR1C3) and C-MYC gene hubs interacting through the AP-1 (c-Jun) transcription factor. PPAR−γ (NR1C3) is a drug target for pioglitazone, which has been shown to reduce depression symptoms in patients with MDD. Using a data-driven approach we were able to overcome challenges of non-i.i.d. data when combining epigenetic studies from MZ twins discordant for MDD. Individually, the studies

Epigenetic differences in monozygotic twins discordant for major depressive disorder.

PubMed

Malki, K; Koritskaya, E; Harris, F; Bryson, K; Herbster, M; Tosto, M G

2016-06-14

Although monozygotic (MZ) twins share the majority of their genetic makeup, they can be phenotypically discordant on several traits and diseases. DNA methylation is an epigenetic mechanism that can be influenced by genetic, environmental and stochastic events and may have an important impact on individual variability. In this study we explored epigenetic differences in peripheral blood samples in three MZ twin studies on major depressive disorder (MDD). Epigenetic data for twin pairs were collected as part of a previous study using 8.1-K-CpG microarrays tagging DNA modification in white blood cells from MZ twins discordant for MDD. Data originated from three geographical regions: UK, Australia and the Netherlands. Ninety-seven MZ pairs (194 individuals) discordant for MDD were included. Different methods to address non independently-and-identically distributed (non-i.i.d.) data were evaluated. Machine-learning methods with feature selection centered on support vector machine and random forest were used to build a classifier to predict cases and controls based on epivariations. The most informative variants were mapped to genes and carried forward for network analysis. A mixture approach using principal component analysis (PCA) and Bayes methods allowed to combine the three studies and to leverage the increased predictive power provided by the larger sample. A machine-learning algorithm with feature reduction classified affected from non-affected twins above chance levels in an independent training-testing design. Network analysis revealed gene networks centered on the PPAR-γ (NR1C3) and C-MYC gene hubs interacting through the AP-1 (c-Jun) transcription factor. PPAR-γ (NR1C3) is a drug target for pioglitazone, which has been shown to reduce depression symptoms in patients with MDD. Using a data-driven approach we were able to overcome challenges of non-i.i.d. data when combining epigenetic studies from MZ twins discordant for MDD. Individually, the studies yielded

Three-dimensional analysis of facial shape and symmetry in twins using laser surface scanning.

PubMed

Djordjevic, J; Jadallah, M; Zhurov, A I; Toma, A M; Richmond, S

2013-08-01

Three-dimensional analysis of facial shape and symmetry in twins. Faces of 37 twin pairs [19 monozygotic (MZ) and 18 dizygotic (DZ)] were laser scanned at the age of 15 during a follow-up of the Avon Longitudinal Study of Parents and Children (ALSPAC), South West of England. Facial shape was analysed using two methods: 1) Procrustes analysis of landmark configurations (63 x, y and z coordinates of 21 facial landmarks) and 2) three-dimensional comparisons of facial surfaces within each twin pair. Monozygotic and DZ twins were compared using ellipsoids representing 95% of the variation in landmark configurations and surface-based average faces. Facial symmetry was analysed by superimposing the original and mirror facial images. Both analyses showed greater similarity of facial shape in MZ twins, with lower third being the least similar. Procrustes analysis did not reveal any significant difference in facial landmark configurations of MZ and DZ twins. The average faces of MZ and DZ males were coincident in the forehead, supraorbital and infraorbital ridges, the bridge of the nose and lower lip. In MZ and DZ females, the eyes, supraorbital and infraorbital ridges, philtrum and lower part of the cheeks were coincident. Zygosity did not seem to influence the amount of facial symmetry. Lower facial third was the most asymmetrical. Three-dimensional analyses revealed differences in facial shapes of MZ and DZ twins. The relative contribution of genetic and environmental factors is different for the upper, middle and lower facial thirds. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Smoking, Dietary Betaine, Methionine, and Vitamin D in Monozygotic Twins with Discordant Macular Degeneration: Epigenetic Implications

PubMed Central

Seddon, Johanna M.; Reynolds, Robyn; Shah, Heeral R.; Rosner, Bernard

2012-01-01

Objective We evaluated monozygotic twin pairs with discordant age-related macular degeneration (AMD) phenotypes to assess differences in behavioral and nutritional factors. Design Case series. Participants Caucasian male twin pairs from the United States Twin Study of Macular Degeneration. Methods Twin pairs were genotyped to confirm monozygosity. Ocular characteristics were evaluated based on fundus photographs using the Wisconsin Grading System and a 5-grade Clinical Age-Related Maculopathy Staging System. We selected twin pairs discordant in each of the following phenotypic categories: Stage of AMD (n = 28), drusen area (n = 60), drusen size (n = 40), and increased pigment area (n = 56). The Wilcoxon signed-rank test and linear regression were used to assess associations between behavioral and nutritional characteristics and each phenotype within discordant twin pairs. Main Outcome Measures Differences in smoking and dietary factors within twin pairs discordant for stage of AMD, drusen area, drusen size, and pigment area. Results Representative fundus photographs depict the discordant phenotypes. Pack-years of smoking were higher for the twin with the more advanced stage of AMD (P = 0.05). Higher dietary intake of vitamin D was present in the twins with less severe AMD (P = 0.01) and smaller drusen size (P = 0.05) compared with co-twins, adjusted for smoking and age. Dietary intakes of betaine and methionine were significantly higher in the twin with lower stage of AMD (P = 0.009) and smaller drusen area (P = 0.03), respectively. Conclusions The twin with the more advanced stage of AMD, larger drusen area, drusen size, and pigment area tended to be the heavier smoker. The twin with the earlier stage of AMD, smaller drusen size and area, and less pigment tended to have higher dietary vitamin D, betaine, or methionine intake. Results suggest that behavioral and nutritional factors associated with epigenetic mechanisms are involved in the etiology of AMD, in

Aggression can be contagious: Longitudinal associations between proactive aggression and reactive aggression among young twins.

PubMed

Dickson, Daniel J; Richmond, Ashley D; Brendgen, Mara; Vitaro, Frank; Laursen, Brett; Dionne, Ginette; Boivin, Michel

2015-01-01

The present study examined sibling influence over reactive and proactive aggression in a sample of 452 same-sex twins (113 male dyads, 113 female dyads). Between and within siblings influence processes were examined as a function of relative levels of parental coercion and hostility to test the hypothesis that aggression contagion between twins occurs only among dyads who experience parental coerciveness. Teacher reports of reactive and proactive aggression were collected for each twin in kindergarten (M = 6.04 years; SD = 0.27) and in first grade (M = 7.08 years; SD = 0.27). Families were divided into relatively low, average, and relatively high parental coercion-hostility groups on the basis of maternal reports collected when the children were 5 years old. In families with relatively high levels of parental coercion-hostility, there was evidence of between-sibling influence, such that one twin's reactive aggression at age 6 predicted increases in the other twin's reactive aggression from ages 6 to 7, and one twin's proactive aggression at age 6 predicted increases in the other twin's proactive aggression from ages 6 to 7. There was also evidence of within-sibling influence such that a child's level of reactive aggression at age 6 predicted increases in the same child's proactive aggression at age 7, regardless of parental coercion-hostility. The findings provide new information about the etiology of reactive and proactive aggression and individual differences in their developmental interplay. © 2015 Wiley Periodicals, Inc.

Monozygotic twin differences in school performance are stable and systematic.

PubMed

von Stumm, Sophie; Plomin, Robert

2018-06-19

School performance is one of the most stable and heritable psychological characteristics. Notwithstanding, monozygotic twins (MZ), who have identical genotypes, differ in school performance. These MZ differences result from non-shared environments that do not contribute to the similarity within twin pairs. Because to date few non-shared environmental factors have been reliably associated with MZ differences in school performance, they are thought to be idiosyncratic and due to chance, suggesting that the effect of non-shared environments on MZ differences are age- and trait-specific. In a sample of 2768 MZ twin pairs, we found first that MZ differences in school performance were moderately stable from age 12 through 16, with differences at the ages 12 and 14 accounting for 20% of the variance in MZ differences at age 16. Second, MZ differences in school performance correlated positively with MZ differences across 16 learning-related variables, including measures of intelligence, personality and school attitudes, with the twin who scored higher on one also scoring higher on the other measures. Finally, MZ differences in the 16 learning-related variables accounted for 22% of the variance in MZ differences in school performance at age 16. These findings suggest that, unlike for other psychological domains, non-shared environmental factors affect school performance in systematic ways that have long-term and generalist influence. Our findings should motivate the search for non-shared environmental factors responsible for the stable and systematic effects on children's differences in school performance. A video abstract of this article can be viewed at: https://youtu.be/0bw2Fl_HGq0. © 2018 John Wiley & Sons Ltd.

Does Learning to Read Improve Intelligence? A Longitudinal Multivariate Analysis in Identical Twins From Age 7 to 16

PubMed Central

Ritchie, Stuart J; Bates, Timothy C; Plomin, Robert

2015-01-01

Evidence from twin studies points to substantial environmental influences on intelligence, but the specifics of this influence are unclear. This study examined one developmental process that potentially causes intelligence differences: learning to read. In 1,890 twin pairs tested at 7, 9, 10, 12, and 16 years, a cross-lagged monozygotic-differences design was used to test for associations of earlier within-pair reading ability differences with subsequent intelligence differences. The results showed several such associations, which were not explained by differences in reading exposure and were not restricted to verbal cognitive domains. The study highlights the potentially important influence of reading ability, driven by the nonshared environment, on intellectual development and raises theoretical questions about the mechanism of this influence. PMID:25056688

Toward automatic phenotyping of retinal images from genetically determined mono- and dizygotic twins using amplitude modulation-frequency modulation methods

NASA Astrophysics Data System (ADS)

Soliz, P.; Davis, B.; Murray, V.; Pattichis, M.; Barriga, S.; Russell, S.

2010-03-01

This paper presents an image processing technique for automatically categorize age-related macular degeneration (AMD) phenotypes from retinal images. Ultimately, an automated approach will be much more precise and consistent in phenotyping of retinal diseases, such as AMD. We have applied the automated phenotyping to retina images from a cohort of mono- and dizygotic twins. The application of this technology will allow one to perform more quantitative studies that will lead to a better understanding of the genetic and environmental factors associated with diseases such as AMD. A method for classifying retinal images based on features derived from the application of amplitude-modulation frequency-modulation (AM-FM) methods is presented. Retinal images from identical and fraternal twins who presented with AMD were processed to determine whether AM-FM could be used to differentiate between the two types of twins. Results of the automatic classifier agreed with the findings of other researchers in explaining the variation of the disease between the related twins. AM-FM features classified 72% of the twins correctly. Visual grading found that genetics could explain between 46% and 71% of the variance.

Kangaroo care with twins: a case study in which one infant did not respond as expected.

PubMed

Jarrell, Julia R; Ludington-Hoe, Susan M; Abouelfettoh, Amel

2009-01-01

The purposes were to relate responses (including unacceptable ones) of twins to shared kangaroo care (KC), to provide explanations for the unexpected responses, and to offer suggestions for safe nursing practice. A descriptive, evaluative case study was conducted. Both twins received KC while their vital signs and maternal breast temperatures were manually recorded every 30 seconds. Descriptive statistics were computed. Identical twins, born to a 19-year-old African-American primigravada, were 34 3/7 weeks postconceptional age with weights of 1,760 and 1,480 g, respectively, when tested. Preterm labor resulted in spontaneous vaginal birth at 30 weeks gestation. Infant heart and respiratory rates, oxygen saturations, abdominal temperatures, and maternal breast temperatures. Infant A's vital signs exceeded acceptable clinical limits during shared KC; vital signs returned to normal range once Infant A was returned to the incubator. Infant B's vital signs approximated clinically acceptable ranges throughout the session. Breast temperatures did not differ. Individuality mandates vigilant assessment of infant responses to shared KC.

Twin vaginal delivery: innovate or abdicate.

PubMed

Easter, Sarah Rae; Taouk, Laura; Schulkin, Jay; Robinson, Julian N

2017-05-01

Neonatal safety data along with national guidelines have prompted renewed interest in vaginal delivery of twins, particularly in the case of the noncephalic second twin. Yet, the rising rate of twin cesarean deliveries, coupled with the national decline in operative obstetrics, raises concerns about the availability of providers who are skilled in twin vaginal birth. Providers are key stakeholders for increasing rates of twin vaginal delivery. We surveyed a group of practicing obstetricians to explore potential barriers to the vaginal birth of twins with a focus on delivery of the noncephalic second twin. Among 107 responding providers, only 57% would deliver a noncephalic second twin by breech extraction. Providers who preferred breech extraction had a higher rate of maternal-fetal medicine subspecialty training (26.2% vs 4.3%; P<.01) and were more likely to be in an academic practice environment (36.1% vs 10.9%; P<.01) and to practice in high-volume centers that deliver >30 sets of twins annually (57.4% vs 34.8%; P=.02). Most providers (54.2%) were familiar with the findings from the recent randomized trial that demonstrated the safety of twin vaginal birth. However, knowledge of the trial was not associated statistically with a preference for breech extraction (62.3% vs 43.5%; P=.05). Providers who preferred breech extraction were more likely to agree with recent society guidelines that encourage the vaginal birth of twins (86.9% vs 63.0%; P<.01). In an adjusted analysis, the 46% of providers with a perceived need for more training were far less likely to prefer breech extraction for delivery of a noncephalic second twin (adjusted odds ratio, 0.38; 95% confidence interval, 0.16-0.95). Furthermore, 57% of providers who would not offer their patient breech extraction would be willing to consult a colleague for support with a noncephalic twin delivery. These results suggest that scientific evidence and society opinion are likely insufficient to reverse the national

Fetoscopic laser ablation of placental anastomoses in twin-twin transfusion syndrome using 'Solomon technique'.

PubMed

Ruano, R; Rodo, C; Peiro, J L; Shamshirsaz, A A; Haeri, S; Nomura, M L; Salustiano, E M A; de Andrade, K K; Sangi-Haghpeykar, H; Carreras, E; Belfort, M A

2013-10-01

To document perinatal outcomes following use of the 'Solomon technique' in the selective photocoagulation of placental anastomoses for severe twin-twin transfusion syndrome (TTTS). Between January 2010 and July 2012, data were collected from 102 consecutive monochorionic twin pregnancies complicated by severe TTTS that underwent fetoscopic laser ablation at four different centers. We compared outcomes between subjects that underwent selective laser coagulation using the Solomon technique (cases) and those that underwent selective laser coagulation without this procedure (controls). Of the 102 pregnancies examined, 26 (25.5%) underwent the Solomon technique and 76 (74.5%) did not. Of the 204 fetuses, 139 (68.1%) survived up to 30 days of age. At least one twin survived in 82 (80.4%) pregnancies and both twins survived in 57 (55.9%) pregnancies. When compared with the control group, the Solomon-technique group had a significantly higher survival rate for both twins (84.6 vs 46.1%; P < 0.01) and a higher overall neonatal survival rate (45/52 (86.5%) vs 94/152 (61.8%); P < 0.01). Use of the Solomon technique remained independently associated with dual twin survival (adjusted odds ratio (aOR), 11.35 (95% CI, 3.11-53.14); P = 0.0007) and overall neonatal survival rate (aOR, 4.65 (95% CI, 1.59-13.62); P = 0.005) on multivariable analysis. There were no cases of recurrent TTTS or twin anemia-polycythemia sequence (TAPS) in the Solomon-technique group. Use of the Solomon technique following selective laser coagulation of placental anastomoses appears to improve twin survival and may reduce the risk of recurrent TTTS and TAPS. Our data support the idea of performing a randomized controlled trial to evaluate the effectiveness of the Solomon technique. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.

Twin Higgs Asymmetric Dark Matter.

PubMed

García García, Isabel; Lasenby, Robert; March-Russell, John

2015-09-18

We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.

Reduced variance in monozygous twins for multiple MR parameters: implications for disease studies and the genetic basis of brain structure.

PubMed

Pell, Gaby S; Briellmann, Regula S; Lawrence, Kate M; Glencross, Deborah; Wellard, R Mark; Berkovic, Samuel F; Jackson, Graeme D

2010-01-15

Twin studies offer the opportunity to determine the relative contribution of genes versus environment in traits of interest. Here, we investigate the extent to which variance in brain structure is reduced in monozygous twins with identical genetic make-up. We investigate whether using twins as compared to a control population reduces variability in a number of common magnetic resonance (MR) structural measures, and we investigate the location of areas under major genetic influences. This is fundamental to understanding the benefit of using twins in studies where structure is the phenotype of interest. Twenty-three pairs of healthy MZ twins were compared to matched control pairs. Volume, T2 and diffusion MR imaging were performed as well as spectroscopy (MRS). Images were compared using (i) global measures of standard deviation and effect size, (ii) voxel-based analysis of similarity and (iii) intra-pair correlation. Global measures indicated a consistent increase in structural similarity in twins. The voxel-based and correlation analyses indicated a widespread pattern of increased similarity in twin pairs, particularly in frontal and temporal regions. The areas of increased similarity were most widespread for the diffusion trace and least widespread for T2. MRS showed consistent reduction in metabolite variation that was significant in the temporal lobe N-acetylaspartate (NAA). This study has shown the distribution and magnitude of reduced variability in brain volume, diffusion, T2 and metabolites in twins. The data suggest that evaluation of twins discordant for disease is indeed a valid way to attribute genetic or environmental influences to observed abnormalities in patients since evidence is provided for the underlying assumption of decreased variability in twins.

Heritability of Lower Urinary Tract Symptoms in Men: A Twin Study

PubMed Central

Afari, Niloofar; Gasperi, Marianna; Forsberg, Christopher W.; Goldberg, Jack; Buchwald, Dedra; Krieger, John N.

2016-01-01

Purpose Symptoms of urinary irritation, urgency, frequency, and obstruction, known as lower urinary tract symptoms (LUTS), are common in urological practice. However, little is known about the etiology or pathogenesis of LUTS, especially the relative contributions of genetic and environmental factors to development of these symptoms. We used a classical twin study design to examine the relative contribution of genetic and environmental factors to the occurrence of LUTS in middle-aged men. Materials and Methods Twins were members of the Vietnam Era Twin (VET) Registry. We used a mail survey to collect lower urinary tract symptoms (LUTS) using the International Prostate Symptom Score (I-PSS) instrument. Twin correlations and biometric modeling was used to determine the relative genetic and environmental contributions to variance in I-PSS total score and individual items. Results Participants were 1,002 monozygotic and 580 dizygotic middle-aged male twin pairs (mean age = 50.2 years; S.D. = 3.0 years). Nearly 25% of the sample had an I-PSS score > 8, indicating at least moderate LUTS. The heritability of the total I-PSS was 37% (95% CI = 32-42%). Heritability estimates ranged from 21% for nocturia to 40% for straining, with moderate heritability (34–36%) for urinary frequency and urgency. Conclusions Genetic factors provide a moderate contribution (20–40%) to LUTS in middle-aged men, suggesting that environmental factors may also contribute substantially to LUTS. Future research is needed to define specific genetic and environmental mechanisms that underlie the development of these symptoms and conditions associated with LUTS. PMID:27312318

Cranioschisis aperta with encephaloschisis in cephalothoracopagus hamster twins.

PubMed Central

Willhite, C C; Rossi, N L; Frakes, R A; Sharma, R P

1985-01-01

The results of gross and histopathological study of a near-term male hamster exencephalic lateral cephalothoracopagus are presented. There was minimal duplication of the internal organs to the point of division at the abdomen. The appendicular skeleton was relatively unaffected by the severe malformations of the axial skeleton. The studies suggested that the lateral relationship of the skull to the spinal columns was a consequence of the presence of two embryonic neural tubes; the chordomesodermal systems of the right and left twins apparently contributed the tissues for the right and left cephalic neural folds, respectively. Anomalies of the vertebral bodies and neural arches were not related to failure of closure of the neural tube as there was no evidence for rachischisis in either body half. Rather, the anomalous axial skeletal elements were apparently the result of competing fields of development by two chordomesodermal systems. The twins were recovered from a dam maintained on a diet consisting of 80% cassava, a cyanide-containing staple consumed by humans in tropical countries. Because the numbers of resorbed implantation sites and malformed litermates were low and the failure to produce conjoined twins in other litters recovered from dams given cassava diets, it appears unlikely that the malformation was related to the composition of the diet. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. PMID:4016585

[Clinical and genetic study of Wilson's disease in affected twins and siblings].

PubMed

Cheng, Nan; Wang, Xun; Yu, Xuen; Zhou, Zhihua; Gao, Mingwei; Rao, Rao; Hu, Jiyuan; Yang, Renmin; Han, Yongzhu

2013-06-01

To study the clinical and genetic characteristics of twins and siblings affected with Wilson's disease (WD). Clinical data and blood samples were collected from the subjects after informed consent was obtained. Genomic DNA was extracted and potential mutations in the exons in ATP7B gene were detected with PCR-DNA sequencing. Short tandem repeat (STR) genotyping was performed to determine the zygosity of the twins. The 5 pairs of twins have all met the diagnostic criteria for WD. STR genotyping has confirmed that 4 pairs were monozygotic twins. 3 pairs of twins had an onset with liver symptoms, the other 2 had an onset with brain symptoms. ATP7B gene mutations were detected in 4 pairs of twins, which have all located in exons 8 and 13. A heterozygous p.R778W mutation in exon 8 and homozygous p.P992L mutation in exon 13 were detected in all patients from one family, whose parents have carried a heterozygous p.R778W mutation and p.P992L heterozygous mutation, respectively, which suggested loss of heterozygosity (LOH). In one family, no mutation was detected in all exons of the ATP7B gene in the patients and their parents. For a triplet, one female was with definite WD and brain symptoms at the onset, one male had subclinical type with WD, whilst another female was completely normal. The triplets and their mother have all carried a p.P992L heterozygous mutation . Above results have confirmed an important role for genetic factors in the pathogenesis of WD. In addition to point mutations, LOH is also involved in the pathogenesis for WD.

Rethinking sexual initiation: pathways to identity formation among gay and bisexual Mexican male youth.

PubMed

Carrillo, Héctor; Fontdevila, Jorge

2011-12-01

The topic of same-sex sexual initiation has generally remained understudied in the literature on sexual identity formation among sexual minority youth. This article analyzes the narratives of same-sex sexual initiation provided by 76 gay and bisexual Mexican immigrant men who participated in interviews for the Trayectos Study, an ethnographic study of sexuality and HIV risk. These participants were raised in a variety of locations throughout Mexico, where they also realized their same-sex attraction and initiated their sexual lives with men. We argue that Mexican male same-sex sexuality is characterized by three distinct patterns of sexual initiation--one heavily-based on gender roles, one based on homosociality, and one based on object choice--which inform the men's interpretations regarding sexual roles, partner preferences, and sexual behaviors. We analyzed the social factors and forms of cultural/sexual socialization that lead sexual minority youth specifically to each of these three patterns of sexual initiation. Our findings confirm the importance of studying same-sex sexual initiation as a topic in its own right, particularly as a tool to gain a greater understanding of the diversity of same-sex sexual experiences and sexual identities within and among ethnic/cultural groups.

Exotic quarks in Twin Higgs models

DOE PAGES

Cheng, Hsin -Chia; Jung, Sunghoon; Salvioni, Ennio; ...

2016-03-14

The Twin Higgs model provides a natural theory for the electroweak symmetry breaking without the need of new particles carrying the standard model gauge charges below a few TeV. In the low energy theory, the only probe comes from the mixing of the Higgs fields in the standard model and twin sectors. However, an ultraviolet completion is required below ~ 10 TeV to remove residual logarithmic divergences. In non-supersymmetric completions, new exotic fermions charged under both the standard model and twin gauge symmetries have to be present to accompany the top quark, thus providing a high energy probe of themore » model. Some of them carry standard model color, and may therefore be copiously produced at current or future hadron colliders. Once produced, these exotic quarks can decay into a top together with twin sector particles. If the twin sector particles escape the detection, we have the irreducible stop-like signals. On the other hand, some twin sector particles may decay back into the standard model particles with long lifetimes, giving spectacular displaced vertex signals in combination with the prompt top quarks. This happens in the Fraternal Twin Higgs scenario with typical parameters, and sometimes is even necessary for cosmological reasons. We study the potential displaced vertex signals from the decays of the twin bottomonia, twin glueballs, and twin leptons in the Fraternal Twin Higgs scenario. As a result, depending on the details of the twin sector, the exotic quarks may be probed up to ~ 2.5 TeV at the LHC and beyond 10 TeV at a future 100 TeV collider, providing a strong test of this class of ultraviolet completions.« less

Rehabilitation of Conjoined Twins Pre- and Postsurgical Separation.

PubMed