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Sample records for dizygotic monochorionic twin

  1. Antenatal Diagnosis of Dizygotic, Monochorionic Twins Following IVF/ICSI

    PubMed Central

    Korsun, P.; Bals-Pratsch, M.; Ortmann, O.; Markus, S.; Germer, U.

    2016-01-01

    Monochorionic twins are usually monozygotic and thus usually have the same sex. A case of monochorionic diamniotic twins following IVF/ICSI and laser treatment of the zona pellucida (“assisted hatching”) is presented in which partial embryo amalgamation appears to have occurred. Discordant sex between the twins was suspected on detailed antenatal ultrasound at 13 + 3 weeks gestation and was confirmed on subsequent examinations. The sexual phenotype at birth was female for one twin and male for the other. Placental histology confirmed the monochorionic, diamniotic situation. Cytogenetic analysis of both twins was carried out postpartum on various tissues. On karyotyping of blood lymphocytes the male and female twins each had one mosaic of male and female cells. Oral mucosal cells showed normal male and female karyotypes respectively. Analysis of urothelium showed a normal result for the male infant, and a weak gonosomal mosaic with an XX and XY constellation for the female infant. At least for blood lymphocytes, a diagnosis of chimerism was proven. PMID:27365544

  2. 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.

  3. Spontaneous unilateral dizygotic twin tubal pregnancy.

    PubMed

    Tam, Teresa; Khazaei, Ali

    2009-02-01

    Spontaneous dizygotic unilateral twin tubal pregnancy is an extremely rare occurrence with a high risk for pregnancy-related mortality, and a diagnostic challenge for obstetricians. We present a case of a 27-year-old woman with spontaneous twin tubal pregnancy. Transvaginal color Doppler sonography revealed 2 separate gestational sacs within the right adnexa, each containing an embryo. Cytogenetic examination of the trophoblastic tissues confirmed the diagnosis of dizygotic twin ectopic pregnancy. Clinical signs and symptoms together with imaging studies help in the diagnosis of this rare variant of ectopic pregnancies.

  4. Neonatal morbidity in growth-discordant monochorionic twins: comparison between the larger and the smaller twin.

    PubMed

    Lopriore, Enrico; Sluimers, Carolien; Pasman, Suzanne A; Middeldorp, Johanna M; Oepkes, Dick; Walther, Frans J

    2012-08-01

    Fetal growth restriction in singletons has been shown to enhance fetal lung maturation and reduce the risk of respiratory distress syndrome due to increased endogenous steroid production. However, data on lung maturation in growth-discordant monochorionic (thus, identical) twins are lacking. Our objective was to compare the risk of severe neonatal morbidity between the larger and the smaller twin in monochorionic twins with birth weight discordance (BWD). We included in the study all consecutive monochorionic diamniotic pregnancies with severe BWD (≥25%) and two live-born twins delivered at our center (n=47 twin pairs). We compared the incidence of neonatal morbidity, particularly respiratory distress syndrome (RDS), and cerebral lesions between the larger and the smaller co-twin. The incidence of severe neonatal morbidity in the larger and smaller twin was 38% (18/47) and 19% (9/47), respectively (odds ratio (OR) 2.66, 95% confidence interval (CI) 0.94-7.44) and was due primarily to the higher incidence of RDS, 32% (15/47) and 6% (3/47), respectively (OR 6.88, 95% CI 1.66-32.83). In conclusion, this study shows that the larger twin in monochorionic twin pairs with BWD is at increased risk of severe neonatal morbidity, particularly RDS, compared to the smaller twin.

  5. 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.

  6. Twin anemia-polycythemia sequence in monochorionic twins: implications for diagnosis and treatment.

    PubMed

    Baschat, Ahmet A; Oepkes, Dick

    2014-09-01

    Twin anemia-polycythemia sequence (TAPS) is a recently described complication of monochorionic placentation characterized by discordance in hemoglobin (Hgb) levels in the absence of amniotic fluid abnormality characteristic of classical twin-twin transfusion syndrome (TTTS). The placental angioarchitecture that predisposes to TAPS consists of small diameter arteriovenous anastomoses and the absence of balancing arterioarterial anastomoses. This vascular pattern occurs sporadically in 3 to 5% of monochorionic twins or iatrogenically following 2 to 13% of selective fetoscopic laser surgeries for TTTS. The diagnosis is based on measurement of the middle cerebral artery peak systolic velocity (MCA-PSV) which is not part of the Quintero staging for TTTS. With mild disease increased MCA-PSV in the anemic donor twin and a decreased MCA-PSV in the recipient twin are characteristic while severe disease is associated with critical Doppler findings, hydrops or single twin demise as in TTTS. Treatment options include fetoscopic laser, fetal blood transfusion, conservative management, and often preterm delivery. The most promising approach to TAPS is its prevention since the iatrogenic form comprises the majority of cases. When the fetoscopic laser technique is modified by coagulating the chorionic plate along the vascular equator (equatorial dichorionization or "Solomon" technique) the incidence of postlaser TAPS and recurrent TTTS is significantly reduced, survival is improved, and there is no increase in complications.

  7. NOTE: Modelling the influence of amnionicity on the severity of twin twin transfusion syndrome in monochorionic twin pregnancies

    NASA Astrophysics Data System (ADS)

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

    2004-03-01

    Clinical treatment for diamniotic monochorionic twin twin transfusion syndrome (TTTS) may include conversion of diamniotic pregnancies to a monoamniotic monochorionic state by disrupting the amnion septum. We sought to test the underlying hypothesis, i.e. that a monoamniotic state reduces the severity of TTTS. With use of our previously developed mathematical model of two equal fetoplacental circulatory units connected by various sizes and types of placental anastomoses, we compared the haemodynamic and amniotic fluid dynamics of monoamniotic and diamniotic twins that develop TTTS. We used three anastomotic patterns that produce severe, moderate or mild forms of TTTS, respectively, in our diamniotic monochorionic twin model. Monoamnionicity was modelled by adding the two amniotic fluid volumes and using the volume-averaged amniotic fluid osmolality. The results were as follows: for severe TTTS, small differences develop between diamniotic and monoamniotic donor twins in fetal urine production, swallowed volume, blood volume, blood pressures, net fetofetal transfusion, and blood and amniotic fluid osmolality. However, the circulatory imbalance between the monoamniotic twins deteriorates similar to that of diamniotic twins. The pathophysiological differences tend to disappear for milder TTTS. In conclusion, our model suggests that the uncommon finding of TTTS in monoamniotic twins is not due to the presence of a single amniotic sac. Rather, clinically significant differences in anastomotic patterns and the delayed or lack of identification of manifestations in monoamniotic twins account for the reduced rate of TTTS diagnosis. Based on these results we expect the clinical disruption of the amnion septum in diamniotic monochorionic TTTS pregnancies to have only minimal benefits.

  8. Successful management of discordant alobar holoprosencephaly in monochorionic diamniotic twins with normal karyotype: a case report.

    PubMed

    Zhang, J; Yang, T; Wang, X; Yu, H

    2015-01-01

    Holoprosencephaly (HPE), a complex brain malformation resulting from incomplete cleavage of the prosencephalon into distinct cerebral hemispheres, is rare in newborns. Two preterm male neonates were born at 34 weeks' and five days' gestation in the monochorionic diamniotic twin pregnancy complicated with pre-eclampsia and intrahepatic cholestasis of pregnancy, and one of them was prenatally diagnosed with alobar HPE by ultrasonography with frontal bossing, hydrocephaly, hypotelorism of eyes, flat nasal bridge, macroglossia, and cheilo/palatoschisis at birth. Karyotyping by G-banding of amniocentesis specimens in normal twin and fetal umbilical blood in both fetuses showed 46, XY. This report expands discordant alobar holoprosencephaly in monochorionic diamniotic twins.

  9. Echogenic material in the fetal gallbladder in a surviving monochorionic twin.

    PubMed

    Sepulveda, W; Stagiannis, K D

    1996-01-01

    Fetal gallstones or echogenic sludge in the fetal gallbladder have rarely been reported prenatally despite the increasing number of ultrasound scans performed during pregnancy. In this report we present a case in which diffuse echogenic material was detected in the fetal gallbladder in a surviving monochorionic twin. This report identifies another predisposing factor for fetal gallstones/sludge in the perinatal period.

  10. Monochorionic twins with the same blood karyotype of 46,XY/47,XYY but different phenotypes.

    PubMed

    Wuttikonsammakit, Piyawadee; Tanawattanacharoen, Somchai; Uerpairojkit, Boonchai

    2010-02-01

    We report the case of a 13-year-old woman who was pregnant with phenotypically discordant monochorionic twins: one with cystic hygroma and hydrops, the other one normal. Fetal blood sampling was performed by intrahepatic blood collection for karyotyping of both fetuses, revealing the same genotype of 46,XY/47,XYY in 2:1 proportion. Phenotypic discordance in monozygotic twins can have various causes, such as placental vascular anatomy, differences in allocation of the number of blastomeres or genetic postzygotic events.

  11. Digitalization of the mother in treating hydrops fetalis in monochorionic twin with Ebstein's anomaly. Case report.

    PubMed

    Koike, T; Minakami, H; Shiraishi, H; Ogawa, S; Matsubara, S; Honma, Y; Sato, I

    1997-01-01

    Hydrops fetalis thought to be due to Ebstein's anomaly was seen at 22 weeks' gestation in one of two fetuses with a monochorionic placenta. Hydrops was treated with maternal digitalization and resolved by the 28th week of gestation. Hydrops did not recur while maternal digitalization continued. A clinical diagnosis of twin-to-twin transfusion syndrome required termination of the pregnancy at 33 weeks of gestation. The twin with Ebstein's anomaly died 22 hours after birth. The other twin survived and was normal at 19 months of age. Thus, administration of digitalis to the mother controlled hydrops fetalis in one fetus, and ultimately led to the survival of the healthy infant.

  12. Monochorionic and dichorionic twin pregnancies discordant for fetal anencephaly: a systematic review of prenatal management options.

    PubMed

    Lust, Annelies; De Catte, Luc; Lewi, Liesbeth; Deprest, Jan; Loquet, Philippe; Devlieger, Roland

    2008-04-01

    The aim of this study was to evaluate the effect of selective feticide (SF) compared to expectant management (EM) on perinatal outcome in dichorionic and monochorionic twins discordant for anencephaly. For this purpose, we conducted a systematic review of literature and added ten unpublished cases. As a result, we found that in dichorionic twins, mean gestational age (GA) at birth in the SF group was 38.0 weeks versus 34.9 weeks (P = 0.0002). Mean birth weight was 2922 g in the SF group versus 2474 g (P = 0.03). In monochorionic twins, mean GA at birth was 35.2 weeks versus 32.7 weeks (P = 0.1). Mean birth weight was 2711 g versus 1667 g (P = 0.0001). We conclude that while SF does not reduce perinatal mortality, it does result in significantly longer gestations and higher birth weight, and appears to be the management of choice in dichorionic twins discordant for anencephaly. In monochorionic twins, SF also increases birth weight, but in view of the complexity of this group, no clear recommendations can be made.

  13. Perinatal Outcomes of Monochorionic-Diamniotic Twin Pregnancies Uncomplicated at 28 Weeks of Gestation.

    PubMed

    Suzuki, Shunji

    2016-01-01

    We examined the prevalence of specific perinatal complications of monochorionic-diamniotic twin pregnancies in cases without any abnormal findings until the second trimester of pregnancy. This was a retrospective cohort study performed at a tertiary perinatal center in Tokyo, Japan. There were 88 cases of uncomplicated monochorionic-diamniotic twin pregnancies at 28 weeks of gestation. In five of them (5.7%), there were serious complications associated with placental circulatory imbalance between the twins during the third trimester of pregnancy. Two cases were complicated by twin-twin transfusion syndrome, two cases were complicated by twin anemia-polycythemia sequence, and one case was complicated by acute twin-twin transfusion syndrome. In the five cases, no abnormal ultrasonographic findings or symptoms were recognized one or two weeks prior to the diagnosis. Fifty-eight cases (65.9%) were delivered at term uneventfully. Serious complications due to placental circulatory imbalance between twins occurred in about 6% of cases during the third trimester of pregnancy.

  14. Coincidence of Incomplete Pentalogy of Cantrell and Meningomyelocele in a Dizygotic Twin Pregnancy

    PubMed Central

    Timur, Hakan; Tokmak, Aytekin; Bayram, Hatice; Şükran Çakar, Esra; Danışman, Nuri

    2015-01-01

    Pentalogy of Cantrell is an extremely rare and lethal syndrome. Ectopia cordis is frequently found in fetuses with POC but not required for incomplete forms. Likewise, meningomyelocele is a relatively uncommon neural tube defect affecting central nervous system and associated with neurological problems. Herein, we presented a woman with dizygotic twin pregnancy having coincidence of incomplete POC and MMC in each individual fetus, which has never been reported previously. PMID:26421202

  15. NOTE: Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion

    NASA Astrophysics Data System (ADS)

    van Gemert, Martin J. C.; van den Wijngaard, Jeroen P. H. M.; Lopriore, Enrico; Pasman, Suzanne A.; Vandenbussche, Frank P. H. A.

    2008-04-01

    Twin-twin transfusion syndrome (TTTS) is a severe complication of monozygotic (identical) twin fetuses sharing one single (monochorionic) placenta. TTTS is caused by a net inter-twin transfusion of blood through placental anastomoses, from one twin (the donor) to the other (the recipient), which link the two feto-placental circulations. Currently, the only reliable method to measure the net inter-twin transfusion clinically is when incomplete laser therapy of TTTS occurs and one of the twins becomes anemic and requires an intra-uterine transfusion of adult red blood cells. Then, differences between adult hemoglobin concentrations measured during the transfusion and at birth relate not only to the net inter-twin transfusion but also to the finite lifetime of the adult red blood cells. We have analyzed this situation, derived the differential equations of adult hemoglobin in the donor and recipient twins, given the solutions and given expressions relating the net inter-twin flow with clinically measured parameters. We have included single and multiple intra-uterine transfusions. In conclusion, because incomplete laser therapy occurs frequently, and some cases require an intra-uterine transfusion, this method may allow collecting a wealth of net inter-twin flow data from clinicians involved in laser therapy of TTTS. To aid to the widespread use of this method, we have presented the equations as clearly as possible in tables for easy use by others.

  16. Placental markers of twin-to-twin transfusion syndrome in diamniotic-monochorionic twins: A morphometric analysis of deep artery-to-vein anastomoses.

    PubMed

    De Paepe, M E; Shapiro, S; Greco, D; Luks, V L; Abellar, R G; Luks, C H; Luks, F I

    2010-04-01

    Twin-to-twin transfusion syndrome (TTTS) is a multifactorial disorder that develops in 9-15% of diamniotic-monochorionic twin gestations. While the pathogenesis of TTTS remains poorly understood, unbalanced deep artery-to-vein (AV) anastomoses have traditionally been implicated in the gradual shift of blood from donor to recipient. The aim of this study was to define the placental markers of twin-to-twin transfusion syndrome, with special emphasis on the deep AV anastomoses. A prospective cohort of 284 consecutive diamniotic/monochorionic twin placentas was examined at Women and Infants Hospital between 2001 and 2008. Following exclusion of monoamniotic, multiple, disrupted and laser-treated placentas, 218 twin placentas (21 TTTS and 197 non-TTTS controls) formed the subject of this study. Placentas were injected with color-coded dyes. Anatomic characteristics and choriovascular anastomotic patterns of TTTS placentas were compared with non-TTTS controls. The TTTS placentas showed significantly higher frequencies of velamentous cord insertion, magistral vascular distribution patterns, uneven placental sharing, absence of AA anastomoses and presence of VV anastomoses. Deep AV anastomoses were identified in >or=95% of TTTS and non-TTTS placentas and were overall more abundant than previously reported. The total and net numbers of AV anastomoses were similar in both groups. However, the net cross-sectional area of AV anastomoses, which also takes into account the caliber of the vessels, was significantly smaller in TTTS placentas. There was no correlation between the direction of the AV imbalance and the twin donor/recipient status. In conclusion, TTTS has distinct placental characteristics, warranting their routine inclusion in the diamniotic-monochorionic placental pathology report. Our findings suggest imbalance of AV anastomoses is not required for the development for TTTS, although their presence, whether balanced or unbalanced, may contribute to the creation or

  17. Identical Choroid Plexus Cysts in Monozygotic Monochorionic Twins.

    PubMed

    Qureshi, Adnan I; Degenhardt, Jan; Axt-Fliedner, Roland; Kohl, Thomas

    2016-01-01

    Choroid plexus cysts have been infrequently reported with chromosomal abnormalities.Isolated choroid plexus cysts in a monozygotic twin pair hints to a genetically determined pathway as a possible cause.

  18. Suicidal Behaviors in Surviving Monozygotic and Dizygotic Co-Twins: Is the Nature of the Co-Twin's Cause of Death a Factor?

    ERIC Educational Resources Information Center

    Segal, Nancy L.

    2009-01-01

    Genetically informative samples can address hereditary and experiential influences on suicide-related behaviors. The frequency of suicide-related behaviors was compared in twins from two survivor groups: (1) those whose co-twins' deaths were suicides (monozygotic [MZ]: n = 47; dizygotic [DZ]: n = 31), and (2) those whose co-twins' deaths were…

  19. Dizygotic twins discordant for early-onset Citrobacter koseri and group B streptococcal sepsis.

    PubMed

    Lin, Wei-Jen; Wang, Chih-Chien; Lo, Wen-Tsung; Chu, Mong-Ling; Lee, Chuen-Ming

    2005-05-01

    Early-onset neonatal sepsis is usually a multisystem fulminant illness with prominent respiratory symptoms, and typically the infant has acquired the organism from the maternal genital tract during the intrapartum period. In this article, we report a rare case of dizygotic twins where each individual suffered early-onset sepsis caused by a different pathogen. Group B streptococcal (GBS) sepsis was diagnosed in twin A 1 day after birth; sepsis and meningitis caused by Citrobacter koseri was diagnosed in twin B at the age of the 4 days. The mother developed pre-eclampsia and fever and the twins were delivered via cesarean section at 35 week's gestation. Twin A received ampicillin treatment for 14 days and recovered fully. Twin B was treated with ceftriaxone for 4 weeks and follow-up brain ultrasound revealed persistent enlargement of the bilateral-lateral ventricles. When empiric antibiotic is considered for the symptomatic twin of a sibling with early-onset GBS infection, samples of blood and cerebrospinal fluid (CSF) should be obtained for culture study before treatment. Adjustment of antibiotic treatment based on the results of cultures and CSF Gram stain and antibiotic susceptibility test is essential.

  20. Conservative treatment for interstitial monochorionic twin pregnancy: case report and review of the published work.

    PubMed

    Berretta, Roberto; Merisio, Carla; Dall'Asta, Andrea; Verrotti, Carla; Rolla, Martino; Bruni, Stefano; Bacchi Modena, Alberto

    2014-03-01

    Interstitial pregnancy is considered one of the most hazardous types of ectopic pregnancies, with a mortality rate of 2-2.5%. We describe a case of a viable monochorionic twin pregnancy in a 35-year-old woman successfully treated with systemic methotrexate associated with bilateral uterine arteries' embolization. β-hCG was undetectable 67 days after the first administration of methotrexate and the ultrasonography performed on day 67 showed the remnant of the gestational sac in the right uterine horn, a thin endometrium and a normal myometrial vascularization. Conservative treatment allowed us to avoid surgical treatment and to preserve the patient's fertility.

  1. A novel C-terminal truncating NR5A1 mutation in dizygotic twins.

    PubMed

    Hattori, Atsushi; Zukeran, Hiroaki; Igarashi, Maki; Toguchi, Suzuka; Toubaru, Yuji; Inoue, Takanobu; Katoh-Fukui, Yuko; Fukami, Maki

    2017-01-01

    Nuclear receptor subfamily 5, group A, member 1 (NR5A1) is a nuclear receptor involved in gonadal and adrenal development. We identified a novel C-terminally truncating NR5A1 mutation, p.Leu423Trpfs*7, in dizygotic twins with 46,XY disorders of sex development. Our results highlight the functional importance of C-terminal region of NR5A1 and indicate that NR5A1 mutations can be associated with intrafamilial phenotypic variations, progressive testicular dysfunction, hypogonadotropic hypogonadism, and borderline adrenal dysfunction.

  2. A novel C-terminal truncating NR5A1 mutation in dizygotic twins

    PubMed Central

    Hattori, Atsushi; Zukeran, Hiroaki; Igarashi, Maki; Toguchi, Suzuka; Toubaru, Yuji; Inoue, Takanobu; Katoh-Fukui, Yuko; Fukami, Maki

    2017-01-01

    Nuclear receptor subfamily 5, group A, member 1 (NR5A1) is a nuclear receptor involved in gonadal and adrenal development. We identified a novel C-terminally truncating NR5A1 mutation, p.Leu423Trpfs*7, in dizygotic twins with 46,XY disorders of sex development. Our results highlight the functional importance of C-terminal region of NR5A1 and indicate that NR5A1 mutations can be associated with intrafamilial phenotypic variations, progressive testicular dysfunction, hypogonadotropic hypogonadism, and borderline adrenal dysfunction. PMID:28326187

  3. Analysis of middle cerebral artery peak systolic velocity in monochorionic twin pregnancies as a method for identifying spontaneous twin anaemia-polycythaemia sequence.

    PubMed

    Sainz, José A; Romero, Cristina; García-Mejido, José; Soto, Fátima; Turmo, Enriqueta

    2014-07-01

    A regular Doppler control evaluation of middle cerebral artery peak systolic velocity is needed in order to identify twin anaemia polycythaemia sequence in monochorionic twin pregnancies. Here, we present a clinical case of spontaneous TAPS, and we review the diagnostic criteria and management strategies for this syndrome.

  4. A case of monochorionic-diamniotic twin pregnancy with polyhydramnios-polyhydramnios sequence.

    PubMed

    Inde, Yusuke; Miyake, Hidehiko; Takaya, Akane; Ono, Shuichi; Igarashi, Miwa; Suzuki, Shunji

    2009-04-01

    We present a case of monochorionic-diamniotic (MD) twin pregnancy with polyhydramnios-polyhydramnios sequence. A 20-year-old woman, gravida 1, para 0, was referred to our hospital at 31 weeks and 6 days' gestation for consultation about a high-risk pregnancy due to the presence of discordant fetal growth pattern (26% of fetal growth discordance) with polyhydramnios in MD twin pregnancy. Ultrasound examination at admission showed a maximal vertical pocket (MVP) of 11.4 cm in twin A and an MVP of 4.7 cm in twin B. At 33 weeks' gestation, the MVPs had increased to 22.2 cm and 10.2 cm, respectively. At 33 weeks and 2 days' gestation, Cesarean section was performed because of uncontrolled uterine contractions associated with polyhydramnios. Twin A was a female weighing 2,280 g, and twin B was a female weighing 1,782 g (22% growth discordance). The estimated amniotic fluid volumes of twins A and B were 5,000 and 1,000 mL, respectively.

  5. IQ similarity in monozygotic and dizygotic twin children: effects of the same versus different examiners: a research note.

    PubMed

    Segal, N L; Russell, J

    1991-05-01

    The Wechsler Intelligence Scale for Children--Revised was administered to two independently identified samples of monozygotic (MZ) and dizygotic (DZ) twin children. Co-twins in the first sample were tested by the same examiner, while co-twins in the second sample were tested by different examiners. IQ intraclass correlations were similar for the two MZ twin samples (.84 and .88), and identical for the two DZ twin samples (.54). The implications of this analysis are discussed with reference to twin study methodology, research on IQ similarity and replication of child development research.

  6. Estimating the Risk of Monochorionic Twins in IVF Pregnancies From the Perspective of a Prenatal Diagnosis Unit.

    PubMed

    Sarais, Veronica; Paffoni, Alessio; Baffero, Giulia Maria; Parazzini, Fabio; Persico, Nicola; Somigliana, Edgardo

    2016-02-01

    The aim of the present work was to estimate the risk of monochorionic twin (MCT) pregnancies in in vitro fertilization (IVF) cycles using data from a prenatal diagnosis unit. This was a retrospective cross-sectional study reporting on the frequency of IVF pregnancies among women attending a prenatal diagnosis service specifically dedicated to the management of monochorionic pregnancies. The observed rate was compared with the local regional rate of IVF births (2.2%). A binomial distribution model was used to calculate the 95% CI of proportions. One hundred and forty-five monochorionic pregnancies were selected. Ten of these were achieved with IVF, corresponding to a rate of 6.9% (95% CI: 3.5-11.8), significantly higher than the background rate in the local population of 2.2%. When considering exclusively monochorionic pregnancies achieving delivery of two viable newborns (n = 132), the number of IVF pregnancies was nine (6.8%, 95% CI: 3.7-12.5). We did not detect major differences in pregnancy outcome between IVF and natural monochorionic pregnancies, with the exception of the proportion of newborns with a neonatal birth < 2,500 g (100% vs. 80%, p = .03). In conclusion, data obtained from the perspective of a prenatal diagnosis unit suggest that women undergoing IVF face a 3- to 4-fold increased risk of monochorionic pregnancies.

  7. Sirenomelia type VI (sympus apus) in one of dizygotic twins at Chiang Mai University Hospital.

    PubMed

    Nokeaingtong, Kwannapas; Kaewchai, Sirirat; Visrutaratna, Pannee; Khuwuthyakorn, Varangthip

    2015-05-14

    Those born with sirenomelia, a rare congenital anomaly, have features resembling a mermaid. Characteristics of sirenomelia are a single lower limb, sacral and pelvic bone defects, and anorectal and urogenital malformations. There is an increased incidence of sirenomelia in males and twins. This case was a preterm male, dizygotic twin and product of in vitro fertilisation. The baby was born by caesarean section due to breech presentation. He was found to have a fused lower extremity and absent external genitalia and anus. The baby passed away shortly after birth due to severe respiratory failure. Radiographic findings showed small lung volume and pneumothoraces. There were multiple segmental fusions of the vertebrae. Single femur and single tibia were presented in a fused lower limb. Autopsy demonstrated large intestinal atresia, intra-abdominal testes, absence of kidney, ureter and bladder, single umbilical artery, agenesis of blood vessels at lower extremity and agenesis of sacrum and coccyx.

  8. [Blood cell chimerism in dizygotic twins conceived by in vitro fertilization].

    PubMed

    Martos-Moreno, G Á; Campos, C; Flores, R; Yturriaga, R; Pérez-Jurado, L A; Argente, J

    2013-10-01

    We present a case of hematopoietic chimerism in dizygotic twins (male and female) conceived by in vitro fertilization (IVF). At 8 years of age a blood karyotype was performed on the female due to the presence of clitoromegaly. Two different lines: 46,XX (53%) and 46,XY (47%) were found. FISH studies confirmed the presence of the SRY gene in 46,XY cells. Karyotyping of the male showed two different lines: 46,XY (58%) and 46,XX (42%). SRY gene was present in 46,XY cells. Microsatellite analyses of blood DNA revealed tetra-allelic contribution at some autosomal loci with similar proportions of maternal and paternal alleles and X/Y chromosome dose. FISH in buccal mucous showed that all cells from the female were 46,XX and those from the male 46,XY. The gonadal karyotype in the female was 46,XX without SRY. Hence, we report 46,XX/46,XY chimerism in dizygotic twins. Blood chimerism was confirmed by performing FISH on the buccal cells of the patients.

  9. Correlation between Chronological Age, Dental Age and Skeletal Age among Monozygoyic and Dizygotic Twins

    PubMed Central

    Gupta, Mohit; Divyashree, R; Abhilash, PR; A Bijle, Mohammed Nadeem; Murali, KV

    2013-01-01

    Introduction: Chronological age, dental development, height and weight measurements, sexual maturation characteristics and skeletal age are some biological indicators that have been used to identify time of growth. Many researchers have agreed that skeletal maturity is closely related to the craniofacial growth, and bones of hand and wrist are reliable parameters in assessing it. The complete hand and wrist radiograph involves 30 bones and assessment of these bones is one elaborate task. The present study is therefore, undertaken to assess the correlation between the chronological age, dental age and skeletal ages among different types of twins. Materials and Methods: The study consisted of 60 subjects (30 twins) aged 8 to 16 years, divided into group of 10 monozygotic, 10 dizygotic and 10 mixed sex twins. The sample was selected from Twin Survey- 2008 conducted by Department of Orthodontics and Dentofacial Orthopaedics, Sree Balaji Dental College and Hospital, Chennai. Their zygosity was determined by sex, blood groups and by the parent. The chronological age was measured by the date of birth given by the parents. Panoramic and hand wrist x-rays were taken. Dental age was assessed by Demerjian et al method and skeletal age by Greulich and Pyle method. The correlation among twins in dental and skeletal ages with the chronological age was assessed using Correlation Coefficient and Student's't' Test. Results: The obtained data was fed into the computer and statistical analysis was done for the same using the SPSS version 10.0. Statistical significance was tested at P<0.05 level. Mean and Standard Deviation, Correlation Coefficient, Student's't' Test statistical methods were employed. The result showed highly significant 'p' value as <0.001 in all the correlations except for mixed pairs. Descriptive statistics in most of the areas demonstrated a non-significant result between zygosity groups. Conclusion: There is a correlation existing between the individual

  10. Identification of Common Genetic Variants Influencing Spontaneous Dizygotic Twinning and Female Fertility

    PubMed Central

    Mbarek, Hamdi; Steinberg, Stacy; Nyholt, Dale R.; Gordon, Scott D.; Miller, Michael B.; McRae, Allan F.; Hottenga, Jouke Jan; Day, Felix R.; Willemsen, Gonneke; de Geus, Eco J.; Davies, Gareth E.; Martin, Hilary C.; Penninx, Brenda W.; Jansen, Rick; McAloney, Kerrie; Vink, Jacqueline M.; Kaprio, Jaakko; Plomin, Robert; Spector, Tim D.; Magnusson, Patrik K.; Reversade, Bruno; Harris, R. Alan; Aagaard, Kjersti; Kristjansson, Ragnar P.; Olafsson, Isleifur; Eyjolfsson, Gudmundur Ingi; Sigurdardottir, Olof; Iacono, William G.; Lambalk, Cornelis B.; Montgomery, Grant W.; McGue, Matt; Ong, Ken K.; Perry, John R.B.; Martin, Nicholas G.; Stefánsson, Hreinn; Stefánsson, Kari; Boomsma, Dorret I.

    2016-01-01

    Spontaneous dizygotic (DZ) twinning occurs in 1%–4% of women, with familial clustering and unknown physiological pathways and genetic origin. DZ twinning might index increased fertility and has distinct health implications for mother and child. We performed a GWAS in 1,980 mothers of spontaneous DZ twins and 12,953 control subjects. Findings were replicated in a large Icelandic cohort and tested for association across a broad range of fertility traits in women. Two SNPs were identified (rs11031006 near FSHB, p = 1.54 × 10−9, and rs17293443 in SMAD3, p = 1.57 × 10−8) and replicated (p = 3 × 10−3 and p = 1.44 × 10−4, respectively). Based on ∼90,000 births in Iceland, the risk of a mother delivering twins increased by 18% for each copy of allele rs11031006-G and 9% for rs17293443-C. A higher polygenic risk score (PRS) for DZ twinning, calculated based on the results of the DZ twinning GWAS, was significantly associated with DZ twinning in Iceland (p = 0.001). A higher PRS was also associated with having children (p = 0.01), greater lifetime parity (p = 0.03), and earlier age at first child (p = 0.02). Allele rs11031006-G was associated with higher serum FSH levels, earlier age at menarche, earlier age at first child, higher lifetime parity, lower PCOS risk, and earlier age at menopause. Conversely, rs17293443-C was associated with later age at last child. We identified robust genetic risk variants for DZ twinning: one near FSHB and a second within SMAD3, the product of which plays an important role in gonadal responsiveness to FSH. These loci contribute to crucial aspects of reproductive capacity and health. PMID:27132594

  11. Doppler detection of arterio-arterial anastomoses in monochorionic twins: feasibility and clinical application.

    PubMed

    Taylor, M J; Denbow, M L; Tanawattanacharoen, S; Gannon, C; Cox, P M; Fisk, N M

    2000-07-01

    The accuracy of in-vivo detection of arterio-arterial anastomoses (AAA) in monochorionic (MC) twins and its predictive value for twin-twin transfusion syndrome (TTTS) was assessed in 105 consecutive MC twins scanned at fortnightly intervals. AAA were sought using spectral and colour energy Doppler and ultrasound findings were compared with placental injection studies. AAA were identified in vivo in 59 (56%) pregnancies and at injection study in 68 (65%). The overall sensitivity and specificity was 85 and 97.3% respectively for the detection of AAA. Detection rates were higher at later gestations, with anterior placentae and with larger diameter AAA. The median insonation time to detect an AAA was 10 min (range 1-30). Where an AAA was identified, 15% of pregnancies (nine of 59) developed TTTS compared to 61% (28 of 46) when no AAA was seen (odds ratio 8.6). We conclude that AAA can be detected in vivo with high sensitivity and specificity without undue prolongation of scanning times and have a role in risk stratification in the antenatal assessment of MC twins.

  12. Risk Factors and Relationship of Cutaneous and Uveal Melanocytic Lesions in Monozygotic and Dizygotic Twin Pairs

    PubMed Central

    Varga, Anita; Szabó, Hajnalka; Orvos, Hajnalka; Kemény, Lajos; Oláh, Judit

    2016-01-01

    Background The similar genetic background of a pair of twins, and the similar environmental impacts to which they are exposed allow an exact and objective investigation of various constitutional and environmental factors in naevus development. As far as we are aware, this is the first published survey that simultaneously examines cutaneous and ocular pigmented lesions in an appreciable sample of identical and non-identical twins. Methods 172 pairs of twins of Caucasian origin were included in this study. A whole-body skin examination and a detailed ophthalmological examination were performed to determine the density of melanocytic lesions. A standardized questionnaire was used to assess the data relating to constitutional, sun exposure and other variables. Results A notably high proportion of the subjects (36.78%) manifested one or more clinically atypical melanocytic naevi (CAMNs), and approximately one-third (31.4%) of them at least one benign uveal pigmented lesion (BUPL). The incidence of iris freckles (IFs), iris naevi (INs) and choroidal naevi (CHNs) proved to be 25.35%, 5.98% and 3.52%, respectively. The interclass correlation coefficients for common melanocytic naevi (CMNs), CAMNs, and INs were 0.77, 0.76 and 0.86 in monozygotic twins, as compared with 0.5, 0.27 and 0.25 in dizygotic twin pairs, respectively. A statistically significant correlation was found between the prevalence of CAMNs and that of INs. Conclusions This significant correlation suggests the existence of a subgroup of Caucasian people with an increased susceptibility to both cutaneous and ocular naevus formation. There is accumulating evidence that, besides the presence of cutaneous atypical naevi, INs can serve as a marker of a predisposed phenotype at risk of uveal melanoma. The correlation between cutaneous and ocular pigmented lesions underlines the need for the adequate ophthalmological screening of subjects with CAMNs and INs. PMID:27486750

  13. Difficult diagnosis and management of an heterokaryotypic monochorionic twin pregnancy with discordant fetal sex and 45,X/47,XYY karyotypes.

    PubMed

    Bohec, Caroline; Douet-Guilbert, Nathalie; Basinko, Audrey; Le Bris, Marie-Josée; Marcorelles, Pascale; Audrézet, Marie-Pierre; Tetefort, Rémi; Bages, Karine; Collet, Michel; Morel, Frederic; De Braekeleer, Marc

    2010-01-01

    We report twins for whom ultrasound examinations revealed a Turner syndrome in the female fetus and a normal male fetus. A selective pregnancy termination was decided on the female fetus with hydrops. The death of both twins called in question the chorionic diagnosis. Amniotic fluid cytogenetic analysis revealed a 45,X karyotype in the female twin and a 47,XYY karyotype in the male twin. Molecular cytogenetic analysis on genital and renal cells showed different levels of 45,X/47,XYY mosaicism in both twins; molecular analysis on the amniocytes showed monozygosity. Monozygotic twins with discordant sex are very rare. This study showed the difficult diagnosis and management of a monochorionic twin pregnancy with discordant fetal sex.

  14. Acute hemorrhage in monochorionic twins with ruptured velamentous vessels: anemic twin resuscitated by its co-twin through placental vascular anastomoses?

    PubMed

    Gillissen, A; Sueters, M; van Lith, J M; Walther, F J; Lopriore, E

    2013-01-01

    Monochorionic (MC) twin pregnancies are at increased risk of several complications including acute or chronic twin-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS). Both TTTS and TAPS result from inter-twin fetofetal transfusion through the placental vascular anastomoses. In addition, MC twin pregnancies are at increased risk of having a velamentous cord insertion, which has been linked with poor perinatal outcome due to risk of rupture of the velamentous vessels. In sporadic cases, these vascular connections may have a positive effect instead of a deleterious effect. We present a case of acute fetal distress in a MC twin pregnancy caused by acute hemorrhage following rupture of velamentous vessels. An emergency cesarean section delivery was performed at 29+2 weeks' gestation. One infant was severely anemic at birth and required immediate treatment with volume expansion and blood transfusion. Acute fetal blood loss through the ruptured vessels led to an acute fetofetal transfusion from the co-twin through the placental vascular anastomoses. Delayed intervention could have resulted in severe hypovolemic shock and acute anemia in both fetuses. Instead, in the current case, placental vascular anastomoses had a transient protective role and allowed transfusion of blood from one co-twin into the circulation of the anemic twin.

  15. Population based study of prevalence of islet cell autoantibodies in monozygotic and dizygotic Danish twin pairs with insulin dependent diabetes mellitus.

    PubMed Central

    Petersen, J. S.; Kyvik, K. O.; Bingley, P. J.; Gale, E. A.; Green, A.; Dyrberg, T.; Beck-Nielsen, H.

    1997-01-01

    OBJECTIVE: To study the comparative importance of environment and genes in the development of islet cell autoimmunity associated with insulin dependent diabetes mellitus. DESIGN: Population based study of diabetic twins. SETTING: Danish population. SUBJECTS: 18 monozygotic and 36 dizygotic twin pairs with one or both partners having insulin dependent diabetes. MAIN OUTCOME MEASURES: Presence of islet cell antibodies, insulin autoantibodies, and autoantibodies to glutamic acid decarboxylase (GAD65) in serum samples from twin pairs 10 years (range 0-30 years) and 9.5 years (2-30 years) after onset of disease. RESULTS: In those with diabetes the prevalence of islet cell antibodies, insulin autoantibodies, and autoantibodies to glutamic acid decarboxylase in the 26 monozygotic twins was 38%, 85%, and 92%, respectively, and in the dizygotic twins was 57%, 70%, and 57%, respectively. In those without diabetes the proportions were 20%, 50%, and 40% in the 10 monozygotic twins and 26%, 49%, and 40% in the 35 dizygotic twins. CONCLUSION: There is no difference between the prevalence of islet cell autoantibodies in dizygotic and monozygotic twins without diabetes, suggesting that islet cell autoimmunity is environmentally rather than genetically determined. Furthermore, the prevalence of islet cell antibodies was higher in the non-diabetic twins than in other first degree relatives of patients with insulin dependent diabetes. This implies that the prenatal or early postnatal period during which twins are exposed to the same environment, in contrast with that experienced by first degree relatives, is of aetiological importance. PMID:9169400

  16. Increased Fetal Plasma Erythropoietin in Monochorionic Twin Pregnancies With Selective Intrauterine Growth Restriction and Abnormal Umbilical Artery Doppler.

    PubMed

    Chang, Yao-Lung; Chao, An-Shine; Peng, Hsiu-Huei; Chang, Shuenn-Dyh; Su, Sheng-Yuan; Chen, Kuan-Ju; Cheng, Po-Jen; Wang, Tzu-Hao

    2016-08-01

    Hypoxia is the primary stimulus for the production of erythropoietin (EPO) in both fetal and adult life. Here, we investigated fetal plasma EPO concentrations in monochorionic (MC) twin pregnancies with selective intrauterine growth restriction (sIUGR) and abnormal umbilical artery (UA) Doppler. We diagnosed sIUGR in presence of (1) birth-weight discordance >20% and (2) either twin with a birth weight <10th percentile. An abnormal UA Doppler was defined as a persistent absent-reverse end diastolic flow (AREDF). The intertwin EPO ratio was calculated as the plasma EPO level of the smaller (or small-for-gestational-age) twin divided by the EPO concentration of the larger (or appropriate-for-gestational-age (AGA)) twin. Thirty-two MC twin pairs were included. Of these, 17 pairs were normal twins (Group 1), seven pairs were twins with sIUGR without UA Doppler abnormalities (Group 2), and eight pairs were twins with sIUGR and UA Doppler abnormalities (Group 3). The highest EPO ratio was identified in Group 3 (p < .001) but no significant differences were observed between Groups 1 and 2. Fetal hemoglobin levels did not differ significantly in the three groups, and fetal EPO concentration did not correlate with gestational age at birth. We conclude that fetal plasma EPO concentrations are selectively increased in MC twin pregnancies with sIUGR and abnormal UA Doppler, possibly as a result of uncompensated hypoxia.

  17. Impact of Monochorionicity and Twin to Twin Transfusion Syndrome on Prenatal Attachment, Post Traumatic Stress Disorder, Anxiety and Depressive Symptoms.

    PubMed

    Beauquier-Maccotta, Berengere; Chalouhi, Gihad E; Picquet, Anne-Laure; Carrier, Aude; Bussières, Laurence; Golse, Bernard; Ville, Yves

    2016-01-01

    Monochronioric (MC) twin pregnancies are considered as high-risk pregnancies with potential complications requiring in-utero interventions. We aimed to assess prenatal attachment, anxiety, post-traumatic stress disorder (PTSD) and depressive symptoms in MC pregnancies complicated with Twin-To-Twin-transfusion syndrome (TTTS) in comparison to uncomplicated monochorionic (UMC) and dichorionic pregnancies (DC). Auto-questionnaires were filled out at diagnosis of TTTS and at successive milestones. Prenatal attachment, PTSD, anxiety and perinatal depression were evaluated respectively by the Prenatal Attachment Inventory (PAI) completed for each twin, the Post-traumatic Checklist Scale (PCLS), the State-Trait Anxiety Inventory (STAI) and the Edinburgh Perinatal Depression Scale (EPDS). There was no significant difference in the PAI scores between the two twins. In the DC and UMC groups, PAI scores increased throughout pregnancy, whilst it didn't for TTTS group. TTTS and DC had a similar prenatal attachment while MC mothers expressed a significantly higher attachment to their fetuses and expressed it earlier. At the announcement of TTTS, 72% of the patients present a score over the threshold at the EPDS Scale, with a higher score for TTTS than for DC (p = 0.005), and UMC (p = 0.007) at the same GA. 30% of mothers in TTTS group have PTSD during pregnancy. 50% of TTTS- patients present an anxiety score over the threshold (STAI-Scale), with a score significantly higher in TTTS than in UMC (p<0.001) or DC (p<0.001). The proportion of subject with a STAI-State over the threshold is also significantly higher in TTTS than in DC at 20 GW (p = 0.01) and at 26 GW (p<0.05). The STAI-state scores in UMC and DC increase progressively during pregnancy while they decrease significantly in TTTS. TTTS announcement constitutes a traumatic event during a pregnancy with an important risk of PTSD, high level of anxiety and an alteration of the prenatal attachment. These results should guide

  18. Impact of Monochorionicity and Twin to Twin Transfusion Syndrome on Prenatal Attachment, Post Traumatic Stress Disorder, Anxiety and Depressive Symptoms

    PubMed Central

    Carrier, Aude; Bussières, Laurence; Golse, Bernard; Ville, Yves

    2016-01-01

    Monochronioric (MC) twin pregnancies are considered as high-risk pregnancies with potential complications requiring in-utero interventions. We aimed to assess prenatal attachment, anxiety, post-traumatic stress disorder (PTSD) and depressive symptoms in MC pregnancies complicated with Twin-To-Twin-transfusion syndrome (TTTS) in comparison to uncomplicated monochorionic (UMC) and dichorionic pregnancies (DC). Auto-questionnaires were filled out at diagnosis of TTTS and at successive milestones. Prenatal attachment, PTSD, anxiety and perinatal depression were evaluated respectively by the Prenatal Attachment Inventory (PAI) completed for each twin, the Post-traumatic Checklist Scale (PCLS), the State-Trait Anxiety Inventory (STAI) and the Edinburgh Perinatal Depression Scale (EPDS). There was no significant difference in the PAI scores between the two twins. In the DC and UMC groups, PAI scores increased throughout pregnancy, whilst it didn’t for TTTS group. TTTS and DC had a similar prenatal attachment while MC mothers expressed a significantly higher attachment to their fetuses and expressed it earlier. At the announcement of TTTS, 72% of the patients present a score over the threshold at the EPDS Scale, with a higher score for TTTS than for DC (p = 0.005), and UMC (p = 0.007) at the same GA. 30% of mothers in TTTS group have PTSD during pregnancy. 50% of TTTS- patients present an anxiety score over the threshold (STAI-Scale), with a score significantly higher in TTTS than in UMC (p<0.001) or DC (p<0.001). The proportion of subject with a STAI–State over the threshold is also significantly higher in TTTS than in DC at 20 GW (p = 0.01) and at 26 GW (p<0.05). The STAI-state scores in UMC and DC increase progressively during pregnancy while they decrease significantly in TTTS. TTTS announcement constitutes a traumatic event during a pregnancy with an important risk of PTSD, high level of anxiety and an alteration of the prenatal attachment. These results should

  19. Placenta share discordance and umbilical artery Doppler change after antenatal betamethasone administration in monochorionic twins with selective intrauterine growth restriction: is there a link?

    PubMed

    Chang, Yao-Lung; Chang, Shuenn-Dyh; Chao, An-Shine; Hsieh, Peter C C; Wang, Chao-Nin; Wang, Tzu-Hao

    2012-10-01

    This study was designed to evaluate the degree of placenta share discordance in relation to the betamethasone-induced return of positive end-diastolic flow in monochorionic twin pregnancies with selective intrauterine growth restriction (sIUGR) and abnormal umbilical artery Doppler. Monochorionic twins with sIUGR was defined as one twin having an estimated fetal weight below the 10th percentile combined with an estimated fetal weight discordance >25%. The umbilical artery Doppler directly prior to (D0) and 24 hours (D1) and 48 hours (D2) after the first dose of betamethasone administration was recorded. The estimated individual placental weight in monochorionic twins was obtained by cutting the placenta along the vascular equator into two territories; the placenta share discordance was calculated as [(estimated individual placental weight of appropriated for gestational age twin- estimated individual placental weight of growth restricted twin)/estimated individual placental weight of appropriated for gestational age twin] × 100%. Six (23.1%) of the 26 included cases achieved betamethasone-induced return of positive umbilical artery end-diastolic flow. The difference of placenta share discordance and birth weight discordance were not significantly different between twins with and without betamethasone-induced return of positive umbilical artery end-diastolic flow. Thus, according to our study results, it was proposed that although the placenta share discordance correlated with the abnormal umbilical artery Doppler in the IUGR fetus in monochorionic twin, the betamethasone-induced return of positive umbilical artery end-diastolic flow, however, did not reveal the similar relationship with the severity of placenta share discordance.

  20. Ductus venosus in the first trimester: contribution to screening of chromosomal, cardiac defects and monochorionic twin complications.

    PubMed

    Maiz, Nerea; Nicolaides, Kypros H

    2010-01-01

    In the first trimester the ductus venosus can be easily identified with color Doppler and a ductus venosus waveform can be obtained by pulsed Doppler. At 11-13 weeks the prevalence of abnormal a-wave in the ductus venosus is inversely related to fetal crown-rump length and maternal serum pregnancy-associated plasma protein-A (PAPP-A), increases with fetal nuchal translucency (NT) thickness and is more common in women of Black racial origin and in fetuses with abnormal karyotype or cardiac defects. Ductus venosus flow provides an independent contribution in the prediction of chromosomal abnormalities when combined with NT and the maternal serum markers of PAPP-A and free beta-hCG, increasing the detection rate to 96% at a false-positive rate of 2.6%. Abnormal ductus venosus flow increases the risk of cardiac defects in fetuses with NT above the 95th centile, and it may increase the risk in fetuses with normal NT. In twin pregnancies, abnormal ductus venosus flow is associated with chromosomal abnormalities and cardiac defects. In monochorionic twins, abnormal flow in the ductus venosus in at least 1 of the fetuses increases the risk of developing twin-to-twin transfusion syndrome.

  1. Causes of delivery and outcomes of very preterm twins stratified to zygosity.

    PubMed

    Spiegler, Juliane; Härtel, Christoph; Schulz, Lena; von Wurmb-Schwark, Nicole; Hoehn, Thomas; Kribs, Angela; Küster, Helmut; Siegel, Jens; Wieg, Christian; Weichert, Jan; Herting, Egbert; Göpel, Wolfgang

    2012-08-01

    The increasing rates of preterm birth among twins implicate that solid data on associated risks and outcomes are required. Assessment of zygosity is often based on clinical criteria (evaluation of placenta; same gender, birth weight discordance as surrogate criteria for monochorionic/monozygotic twins). The aim of this study was to compare clinical versus genetic assessment of zygosity and to compare causes of preterm delivery as well as outcome data of very-low-birth-weight (VLBW; birth weight <1,500 g) twins stratified to zygosity. In a multicenter study, we selected n=176 sets of same gender twins and determined zygosity genetically. In a subgroup of 123 sets of twins, the attending physicians at the study centers were asked to document the parameter 'zygosity' (monozygotic/dizygotic) on the basis of their clinical judgment. Concordance between genetic and clinical assessment was 62.7% for monozygotic twins and 88.9% for dizygotic twins, respectively. Outcome parameters (death, BPD, ROP, NEC, IVH) were comparable in both groups. Genetically dizygotic twins were significantly more often born due to intrauterine infection (33% vs. 20% in monozygotic twins, p<.01) and antenatal antibiotics were more frequently given to mothers of dizygotic twins (62% vs. 47% in monozygotic twins, p<.01). Obstetric complications such as twin-twin-transfusion-syndrome were only seen in monozygotic twins as expected. The unexpected increase of antenatal antibiotic treatment and birth due to intrauterine infection in dizygotic twins should be confirmed in additional VLBW twin-cohorts.

  2. [A case of a dizygotic twin pregnancy where superfetation seems indisputable].

    PubMed

    Bourgoin, P; Marc, J; Merger, C; Delatte, J N

    1995-01-01

    A case of superfoetation is presented. Difference of age (3 weeks) between twins was established by ultrasound at 10 weeks, and persisted through subsequent echographic surveillance up to delivery at 39 of amenorrhea with twin 39 and 36 weeks old. Only three publications in recent international literature are related to superfoetation. An attempt is made to try to understand superfoetation and to clearly differentiate it from superovulation.

  3. A case of a surviving co-twin diagnosed with porencephaly and renal hypoplasia after a single intrauterine fetal death at 21 weeks of gestation in a monochorionic monoamniotic twin pregnancy.

    PubMed

    Machino, Hidenori; Iriyama, Takayuki; Nakayama, Toshio; Komatsu, Atsushi; Nagamatsu, Takeshi; Osuga, Yutaka; Fujii, Tomoyuki

    2017-01-01

    Monochorionic monoamniotic (MM) twin pregnancy carries a high risk of intrauterine fetal death (IUFD). Single IUFD in an MM twin pregnancy prior to 22 weeks of gestation has been reported to be strongly correlated with double twin demise. To our knowledge, there are no case reports on the natural course of a surviving co-twin in an MM twin pregnancy resulting in live birth after a single IUFD prior to 22 weeks of gestation. Here, we report a case of a surviving co-twin, after a single IUFD at 21 weeks of gestation in a MM twin pregnancy, with an antenatal diagnosis of renal hypoplasia and severe neurological damage leading to porencephaly, and live birth at 36 weeks of gestation.

  4. A case of a surviving co-twin diagnosed with porencephaly and renal hypoplasia after a single intrauterine fetal death at 21 weeks of gestation in a monochorionic monoamniotic twin pregnancy

    PubMed Central

    Machino, Hidenori; Iriyama, Takayuki; Nakayama, Toshio; Komatsu, Atsushi; Nagamatsu, Takeshi; Osuga, Yutaka; Fujii, Tomoyuki

    2017-01-01

    Monochorionic monoamniotic (MM) twin pregnancy carries a high risk of intrauterine fetal death (IUFD). Single IUFD in an MM twin pregnancy prior to 22 weeks of gestation has been reported to be strongly correlated with double twin demise. To our knowledge, there are no case reports on the natural course of a surviving co-twin in an MM twin pregnancy resulting in live birth after a single IUFD prior to 22 weeks of gestation. Here, we report a case of a surviving co-twin, after a single IUFD at 21 weeks of gestation in a MM twin pregnancy, with an antenatal diagnosis of renal hypoplasia and severe neurological damage leading to porencephaly, and live birth at 36 weeks of gestation. PMID:28116109

  5. [Heterotopic pregnancy with intrauterine dizygotic twins following embryo transfer in the blastocyst phase].

    PubMed

    Barrón Vallejo, J; Ortega Díaz, R; Kably Ambe, A

    1999-04-01

    Ectopic pregnancy is a common complication of in vitro fertilization and embryo transfer (IVF-ET). On other hand, heterotopic pregnancy complicates 1-2% of all IVF-ET pregnancies. Tubal damage as reason for treatment and multiple embryo transfer might predispose patients to this complication. We present a successful treated case of an infertile patient that developed simultaneous twin intra- and single extra- uterine pregnancy after blastocyst-stage embryo transfer. In IVF-ET patients presence of an intrauterine gestation not exclude the possibility of a concomitant extrauterine pregnancy. Awareness of the possibility of heterotopic pregnancy after IVF-ET plays an important role in the successful treatment of this reproductive complication. Transfer of good quality embryos can be a risk factor to develop heterotopic pregnancy.

  6. Sensory motor and functional skills of dizygotic twins: one with Smith-Magenis syndrome and a twin control.

    PubMed

    Smith, Michaele R; Hildenbrand, Hanna; Smith, Ann C M

    2009-01-01

    Smith-Magenis syndrome (SMS), the result of an interstitial deletion within chromosome 17p11.2, is a disorder that may include minor dysmorphic features, brachydactyly, short stature, hypotonia, speech delays, cognitive deficits, signs of peripheral neuropathy, scoliosis, and neurobehavioral problems including sleep disturbances and maladaptive repetitive and self-injurious behaviors. Physical and occupational therapists provide services for children who have the syndrome, whose genetic disorder is frequently not identified or diagnosed before 1 year of age. A comprehensive physical and occupational therapy evaluation was completed in nonidentical twins with one having SMS, using the Sensory Profile; Brief Assessment of Motor Function (BAMF); Peabody Developmental Motor Scales, Second Edition (PDMS-2); and Pediatric Evaluation of Disability Inventory (PEDI). This provides a framework for conducting assessments to enhance early detection and interdisciplinary management with this specialized population.

  7. The Contribution of Prenatal Stress to the Pathogenesis of Autism as a Neurobiological Developmental Disorder: A Dizygotic Twin Study

    ERIC Educational Resources Information Center

    Claassen, M.; Naude, H.; Pretorius, E.; Bosman, M. C.

    2008-01-01

    This paper reports on the contribution of prenatal stress to the pathogenesis of autism as a neurobiological developmental disorder in a dizygotic study. The aim was to explore whether the neurobiological impact of stress prior to week 28 of gestation might be related to the pathogenesis of autism. The following data-generating strategies were…

  8. Effective treatment of cervical incompetence in a monochorionic monoamniotic twin pregnancy with a rescue cervical cerclage and pessary--a case report and review of literature.

    PubMed

    Kosińska-Kaczyńska, Katarzyna; Szymusik, Iwona; Bomba-Opoń, Dorota; Brawura-Biskupski-Samaha, Robert; Wegrzyn, Piotr; Wielgoś, Mirosław

    2012-12-01

    A monochorionic monoamniotic (MCMA) twin pregnancy is the rarest form of twin gestation, accounting for around 1:10000 to 1:20000 of all deliveries regardless of the region of the world. All multiple gestations have a higher risk of preterm delivery due to either preterm uterine contractions or asymptomatic cervical shortening (cervical incompetence). A case of a 28-year-old primigravida in MCMA twin pregnancy with cervical incompetence diagnosed at 22 weeks of gestation is presented. After obtaining cervical swabs, negative laboratory infection parameters and confirming concordant gestational age on ultrasound scan with no structural abnormalities of both fetuses, the patient was qualified for an emergency cervical cerclage according to Wurm-Hefner method. Five days after the procedure, a cervical pessary was additionally inserted. She was administered antibiotics and steroids. The wellbeing of both fetuses was strictly monitored by means of cardiotocography tracing and ultrasound examinations, on which they were both eutrophic, with no abnormalities in Doppler blood flow patterns. Spontaneous premature rupture of membranes took place at 32 weeks of gestation, a cesarean section was performed and two female fetuses of 1740 g and 1760 g were delivered. They both required antibiotics because of congenital pneumonia, but no respiratory support was necessary The twins were discharged from the hospital 22 days after birth in good general condition. This case of a rescue cervical cerclage and pessary used simultaneously can be an example of an effective method of cervical incompetence treatment in twin pregnancies.

  9. Expanded DMPK repeats in dizygotic twins referred for diagnosis of autism versus absence of expanded DMPK repeats at screening of 330 children with autism

    PubMed Central

    Musova, Zuzana; Hancarova, Miroslava; Havlovicova, Marketa; Pourova, Radka; Hrdlicka, Michal; Kraus, Josef; Trkova, Marie; Stejskal, David; Sedlacek, Zdenek

    2016-01-01

    Myotonic dystrophy type 1 (DM1) belongs to the broad spectrum of genetic disorders associated with autism spectrum disorders (ASD). ASD were reported predominantly in congenital and early childhood forms of DM1. We describe dizygotic twin boys with ASD who were referred for routine laboratory genetic testing and in whom karyotyping, FMR1 gene testing, and single nucleotide polymorphism array analysis yielded negative results. The father of the boys was later diagnosed with suspected DM1, and testing revealed characteristic DMPK gene expansions in his genome as well as in the genomes of both twins and their elder brother, who also suffered from ASD. In accord with previous reports on childhood forms of DM1, our patients showed prominent neuropsychiatric phenotypes characterized especially by hypotonia, developmental and language delay, emotional and affective lability, lowered adaptability, and social withdrawal. The experience with this family and multiple literature reports of ASD in DM1 on the one side but the lack of literature data on the frequency of DMPK gene expansions in ASD patients on the other side prompted us to screen the DMPK gene in a sample of 330 patients with ASD who were first seen by a geneticist before they were 10 years of age, before the muscular weakness, which may signal DM1, usually becomes obvious. The absence of any DMPK gene expansions in this cohort indicates that targeted DMPK gene testing can be recommended only in ASD patients with specific symptoms or family history suggestive of DM1. PMID:27695335

  10. Monochorionic-diamniotic discordant growth in a twin pregnancy with one fetus affected by Ebstein's anomaly of tricuspid leaflets.

    PubMed

    Fukami, Tatsuya; Goto, Maki; Matsuoka, Sakiko; Sorano, Sumire; Tohyama, Atsushi; Yamamoto, Hiroko; Nakamura, Sumie; Matsuoka, Ryoei; Tsujioka, Hiroshi; Eguchi, Fuyuki

    2016-07-01

    Our patient was diagnosed as having discordant twin growth with Ebstein's anomaly in the larger fetus. Cardiac function was deteriorated in accordance with progression of gestational age. Our observation indicated cardiac failure of the larger fetus. The most important issue in this situation is management of the timing of delivery.

  11. Monochorionic twin delivery after conservative surgical treatment of a patient with severe diffuse uterine adenomyosis without uterine rupture

    PubMed Central

    Kwack, Jae Young; Jeon, Su-Bun; Kim, Keuna; Lee, Soo-Jeong

    2016-01-01

    A 31-year-old nulliparous woman with severe diffuse uterine adenomyosis, which replaced nearly the whole uterine myometrium, visited our hospital due to severe dysmenorrhea, menorrhagia, and a desire to have a baby. The patient had a history of two spontaneous abortions. Laparotomic adenomyomectomy with transient occlusion of uterine arteries (TOUA) was performed safely and the patient tried in vitro fertilization and achieved a intrauterine twin pregnancy after recovery time of the operation. At 31+6 weeks of gestation, a male neonate baby weighing 1,620 g and a male neonate baby weighing 1,480 g were born by transverse lower segment cesarean delivery. There was no complication after the operation. The babies were discharged after receiving routine neonatal intensive care for neonatal respiratory distress syndrome. Adenomyomectomy with TOUA technique would be an option for conservative surgical treatment in patients with severe diffuse whole uterine adenomyosis. This is the first report of twin pregnancy after diffuse whole uterine adenomyomectomy with TOUA. PMID:27462599

  12. Obstetric outcomes of monochorionic pregnancies conceived following assisted reproductive technology: A retrospective study

    PubMed Central

    Mascarenhas, Mariano; Kamath, Mohan S.; Muthukumar, K; Mangalaraj, Ann M.; Chandy, Achamma; Aleyamma, TK

    2014-01-01

    OBJECTIVES: The overwhelming numbers of twins following assisted reproductive technology (ART) are dichorionic twins, but monochorionic twins account for around 0.9% of post ART pregnancies. The data for post ART-monochorionic pregnancy outcomes are scarce due to the rarity of this condition. Hence, we evaluated the obstetric outcomes of monochorionic and dichorionic pregnancies conceived on ART. SETTINGS: University teaching hospital. STUDY DESIGN: A case–control study of monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA) pregnancies conceived following ART treatment. Charts of all women who conceived following ART from 2008 to 2013 were screened. Among them, the monochorionic twins diagnosed in the first trimester were included and their obstetric outcome was followed-up. For comparison, an equal number of dichorionic twin pregnancies from age and body mass index matched mothers was selected. RESULTS: The baseline clinical characteristics were similar between the two groups. MCDA group had a higher miscarriage rate (50%) than the DCDA group (10%), with three seconds trimester miscarriages in the MCDA group. The live birth rates were lower in the MCDA versus DCDA group (40% vs. 90%). Among triplet pregnancies with a monochorionic component, the live birth rate was only 25%. CONCLUSIONS: Monochorionic pregnancies following ART have poorer obstetric outcomes when compared to dichorionic pregnancies. For monochorionic pregnancies following ART, intensive antenatal surveillance at a tertiary level obstetric and neonatal center may help optimize the outcome. PMID:25191025

  13. 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.

  14. Serum microRNAs explain discordance of non-alcoholic fatty liver disease in monozygotic and dizygotic twins: a prospective study

    PubMed Central

    Zarrinpar, Amir; Gupta, Shakti; Maurya, Mano R; Subramaniam, Shankar; Loomba, Rohit

    2016-01-01

    Objective In the setting where two individuals are genetically similar, epigenetic mechanisms could account for discordance in the presence or absence of nonalcoholic fatty liver disease (NAFLD). This study investigated if serum microRNAs (miRs) could explain discordance in NAFLD. Design This is a cross-sectional analysis of a prospective cohort study of 40 (n=80) twin-pairs residing in Southern California. All participants underwent a standardised research visit, liver MRI using proton-density fat fraction to quantify fat content and miR profiling of their serum. Results Among the 40 twin-pairs, there were 6 concordant for NAFLD, 28 were concordant for non-NAFLD and 6 were discordant for NAFLD. The prevalence of NAFLD was 22.5% (18/80). Within the six discordant twins, a panel of 10 miRs differentiated the twin with NAFLD from the one without. Two of these miRs, miR-331-3p and miR-30c, were also among the 21 miRs that were different between NAFLD and non-NAFLD groups (for miR-331-3p: 7.644±0.091 vs 8.057 ±0.071, respectively, p=0.004; for miR-30c: 10.013 ±0.126 vs 10.418±0.086, respectively, p=0.008). Both miRs were highly heritable (35.9% and 10.7%, respectively) and highly correlated with each other (R=0.90, p=2.2×10−16) suggesting involvement in a common mechanistic pathway. An interactome analysis of these two miRs showed seven common target genes. Conclusions Using a novel human twin-study design, we demonstrate that discordancy in liver fat content between the twins can be explained by miRs, and that they are heritable. PMID:26002934

  15. The North American Fetal Therapy Network Consensus Statement: prenatal management of uncomplicated monochorionic gestations.

    PubMed

    Emery, Stephen P; Bahtiyar, Mert Ozan; Dashe, Jodi S; Wilkins-Haug, Louise E; Johnson, Anthony; Paek, Bettina W; Moon-Grady, Anita J; Skupski, Daniel W; OʼBrien, Barbara M; Harman, Christopher R; Simpson, Lynn L

    2015-05-01

    Owing to vascular connections within a single placenta, monochorionic gestations present distinctive prenatal management challenges. Complications that can arise as a result of unbalanced hemodynamic exchange (twin-twin transfusion syndrome and twin anemia polycythemia sequence) and unequal placental sharing (selective fetal growth restriction) should be kept in mind while prenatal management is being planned. Because of unique monochorionic angioarchitecture, what happens to one twin can directly affect the other. Death of one twin can result in death or permanent disability of the co-twin. Early detection of these unique disease processes through frequent ultrasonographic surveillance may allow the opportunity for earlier referral, intervention, or both and potentially better outcomes. Therefore, monochorionic gestations should be managed differently than dichorionic gestations or singletons. The purpose of this document is to present in detail methods for monitoring and management of uncomplicated monochorionic gestations and to review the evidence for the roles of these methods for detection of complications in clinical practice. Finally, we present evidence-based and expert opinion-supported recommendations developed by the North American Fetal Therapy Network for the diagnosis, surveillance, and delivery of uncomplicated monochorionic gestations.

  16. Managing Monoamniotic Twin Pregnancies.

    PubMed

    Post, Annalisa; Heyborne, Kent

    2015-09-01

    Monoamniotic twins comprise a rare but important subset of twins at risk of unique and serious complications, placing them at the highest risk of perinatal mortality of all twin gestations. In addition to risks faced by all twins (prematurity, selective growth restriction), all monochorionic twins (twin-twin transfusion syndrome), and all monozygotic twins (congenital anomalies), monoamniotic twins face the unique risk of cord entanglement. Accordingly, early diagnosis, screening for fetal anomalies, surveillance for twin-twin transfusion syndrome, decisions related to monitoring after viability, and timing and route of delivery are all critical. Herein, we present recommendations for optimal management.

  17. Vascular programming in twins: the effects of chorionicity and fetal therapy for twin-to-twin transfusion syndrome.

    PubMed

    Gardiner, H M; Barlas, A; Matsui, H; Diemert, A; Taylor, M J O; Preece, J; Gordon, F; Greenwald, S E; Hecher, K

    2012-06-01

    We assessed vascular programming in genetically identical monochorionic twin pairs with twin-to-twin transfusion syndrome (TTTS) treated differently in utero by serial amnioreduction or fetal laser arterial photocoagulation. This case-control study re-assessed four twin groups at median 11 years comprising 20 pairs of monochorionic diamniotic twins: nine treated by amnioreduction (TTTS-amnio) and eleven by laser (TTTS-laser) with seven monochorionic and six dichorionic control pairs. Outcome measures were current blood pressure (BP), brachio-radial arterial stiffness derived from pulse wave velocity (PWV), resting microcirculation (Flux) and response to heating and post-occlusive reactive hyperaemia measured using laser Doppler. Potential confounders [PWV and BP at first study, current height, weight, heart rate and twin type (ex-recipient, ex-donor or heavier/lighter of pair)] were accounted for by Mixed Linear Models statistical methodology. PWV dichorionic > monochorionic (P = 0.024); systolic and diastolic BP dichorionic > TTTS-amnio and TTTS-laser (P = 0.004, P = 0.02 and P = 0.005, P = 0.02, respectively). Within-twin pair pattern of PWV discordance was similar in laser treated and dichorionic controls (heavier-born > lighter), opposite to TTTS-amnio and monochorionic controls. Flux monochorionic > dichorionic (P = 0.044) and heavier > lighter-born (P = 0.024). TTTS-laser and dichorionic diamniotic showed greatest hyperaemic responses (dichorionic > TTTS-amnio or monochorionic controls (P = 0.007, P = 0.025). Hyperaemic responses were slower in heavier-born twins (P = 0.005). In summary, monochorionic twins had lower BP, arterial stiffness and increased resting vasodilatation than dichorionic twins implying shared fetal circulation affects vascular development. Vascular responses in laser-TTTS were similar to dichorionic and opposite to TTTS-amnio suggesting a lasting effect of fetal therapy on vascular health.

  18. Emergent Novelties in the Mentality of Dizygotic Twins.

    ERIC Educational Resources Information Center

    Bierschenk, Bernhard

    Scanator is an extremely valuable tool in the functional analysis of qualitative stability in text building behavior during writing. Scanator also allows for a detailed investigation of subtle changes emerging in the structural relations of emergent novelties. This study focused on the extension of the application of Scanator to one pair of…

  19. A twin study on age-related macular degeneration.

    PubMed Central

    Meyers, S M

    1994-01-01

    A prospective twin study on age-related macular degeneration (AMD) recruited 83 monozygotic pairs, 28 dizygotic pairs, and one triplet set from 1986 through 1993. Zygosity was determined by genetic testing of red cell markers, HLA antigens, or specific DNA loci. There were no twin pairs in which I collected data on only one twin. To decrease ascertainment bias, after 1991 the recruitment notice did not mention AMD, and I did not ask about a history of eye disease before the eye examination. Because of this, twin pairs recruited from 1986 through 1991 were statistically analyzed separately from those after January 1, 1992. From 1986 through 1991, 23 twin pairs were recruited; 11 monozygotic and 2 dizygotic pairs had nonAMD retinal changes or no retinal abnormalities, 9 monozygotic pairs with AMD were all concordant, and 1 dizygotic pair was discordant for basal laminar drusen. The concordance rate of AMD did not differ significantly between monozygotic and dizygotic twin pairs (P = .10) for 1986 through 1991. In 1992 and 1993, 88 twin pairs and one triplet set were recruited; 49 monozygotic and 19 dizygotic pairs had nonAMD retinal changes or no retinal abnormalities, 14 monozygotic pairs with AMD were all concordant, and 2 of 7 dizygotic pairs were concordant for AMD. The nonidentical triplets (1 with and 2 without AMD) were categorized as one of the discordant dizygotic pairs in the statistical evaluation. In nontwin age-matched (within 2 or 5 years of age) or age- and sex-matched sibling pairs the concordance rate of AMD ranged from 16% to 25%. The concordance rate of AMD was significantly higher in monozygotic than in dizygotic twins (P = .001) for 1992 and 1993. The concordance rate was higher for monozygotic twin pairs recruited in 1992 and 1993 than in any of the four subsets of nontwin age-method or age- and sex-matched sibling pairs (P < .0001). Overall, from 1986 through 1993, 23 of 23 monozygotic and 2 of 8 dizygotic twin pairs were concordant for AMD

  20. [Multicystic encephalomalacia in a surviving twin after death of the other twin in utero].

    PubMed

    Lajarrige, C; Adafer, M; Yassine, B; Atallah, W; Mouthemy, G; Klink, R; Khoury, M; Bouhelier, P; Kremp, L

    1993-01-01

    A case of multicystic encephalomalacia in a twin is reported. The other twin died in utero at 32 weeks gestational age. Because there was no evidence of fetal distress the pregnancy was allowed to continue until 36 weeks gestational age. Injuries to the surviving twin due to disseminated intravascular coagulation (DIVC) and vascular thrombosis or to anoxia and ischemia may occur when there are anastomoses between the circulatory systems of the two twins, i.e., in monochorionic pregnancies. The classically recommended strategy is to wait for adequate maturity of the surviving fetus (36 weeks). It is suggested that this attitude may be overly expectant and may deserve reappraisal.

  1. 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%…

  2. Variations in the Binary Conception Model in Twinning.

    ERIC Educational Resources Information Center

    Lord, Thomas R.

    1988-01-01

    Presents a brief summary of the transformation of a single fertilized ovum into a multi-celled human. Discusses the similarities and differences of identical and non-identical twins. Cites twin pairs that do not neatly fit the monozygotic or dizygotic schemes of human development. (RT)

  3. Twin Reversed Arterial Perfusion: To Treat or Not?

    PubMed Central

    Verma, Meesha; Goel, Poonam; Punia, RPS

    2017-01-01

    Acardiac twinning or Twin Reverse Arterial Perfusion (TRAP)-sequence is a rare complication of monochorionic twin pregnancy. Whether to start elective or therapeutic treatment in TRAP-sequence is still controversial. In the present case, acardiac twin was not diagnosed till her delivery at 39 weeks. A healthy baby weighing 2.45 kg was delivered along with another amorphous mass (acardiac twin) of about 150 g which was attached to the placenta with a short and separate cord. As outcome of normal twin vary according to the growth of acardiac twin, frequent follow-up of the normal twin is required to look for the features of heart failure. Hence, the diagnosis of acardiac twin is essential in early pregnancy. PMID:28274006

  4. Twinning and heteropaternity in chimpanzees (Pan troglodytes).

    PubMed

    Ely, John J; Frels, William I; Howell, Sue; Izard, M Kay; Keeling, Michale E; Lee, D Rick

    2006-05-01

    Unlike monozygotic (MZ) twins, dizygotic (DZ) twins develop from separate ova. The resulting twins can have different sires if the fertilizing sperm comes from different males. Routine paternity testing of a pair of same-sexed chimpanzee twins born to a female housed with two males indicated that the twins were sired by two different males. DNA typing of 22 short-tandem repeat (STR) loci demonstrated that these twins were not MZ twins but heteropaternal DZ twins. Reproductive data from 1926-2002 at five domestic chimpanzee colonies, including 52 twins and two triplets in 1,865 maternities, were used to estimate total twinning rates and the MZ and DZ components. The average chimpanzee MZ twinning rate (0.43%) equaled the average human MZ rate (0.48%). However, the chimpanzee DZ twinning rate (2.36%) was over twice the human average, and higher than all but the fertility-enhanced human populations of Nigeria. Similarly high twinning rates among African chimpanzees indicated that these estimates were not artifacts of captivity. Log-linear analyses of maternal and paternal effects on recurrent twinning indicated that females who twinned previously had recurrence risks five times greater than average, while evidence for a paternal twinning effect was weak. Chimpanzee twinning rates appear to be elevated relative to corresponding estimated human rates, making twinning and possibly heteropaternity more important features of chimpanzee reproductive biology than previously recognized.

  5. NOTE: Increasing cardiac output and decreasing oxygenation sequence in pump twins of acardiac twin pregnancies

    NASA Astrophysics Data System (ADS)

    van Gemert, Martin J. C.; Umur, Asli; van den Wijngaard, Jeroen P. H. M.; Van Bavel, Ed; Vandenbussche, Frank P. H. A.; Nikkels, Peter G. J.

    2005-02-01

    An acardiac twin pregnancy is a rare but serious complication of monochorionic twinning and consists of an acardiac twin and a pump twin. The acardiac twin is a severely malformed fetus that lacks most organs, particularly a heart, but grows during pregnancy because it is perfused by the developmentally normal pump twin via a set of arterioarterial and venovenous placental anastomoses. Pump twins die intrauterine or neonatally in about 50% of the cases. Because the effects of an acardiac mass on the pump twin's development are incompletely known, methods for outcome prognosis are currently not available. We sought to derive simple relations for the pump twin's excess cardiac output and decreased oxygenation and to use available clinical cases for a preliminary test of the model. As a method, we used a theoretical flow model to represent the fetoplacental circulation of an acardiac twin pregnancy and estimated blood deoxygenation and reoxygenation following perfusion of the two bodies and placentas, respectively. The results show the pump twin's excess cardiac output and decrease of venous oxygen saturation to depend on the ratio of pump twin to acardiac twin umbilical blood flow, whose ratio can be measured by ultrasonography. The clinical cases show a decreasing umbilical flow ratio with gestation. In conclusion, prospective serial study is necessary to test whether measurement of umbilical flow ratios allows monitoring the pump twin's pathophysiologic development, possibly resulting in a guideline for prognosis of pump twin survival.

  6. Down's syndrome in twins of unlike sex.

    PubMed Central

    Avni, A; Amir, J; Wilunsky, E; Katznelson, M B; Reisner, S H

    1983-01-01

    The occurrence of Down's syndrome in both dizygotic twins appears to be very rare. A case of twins of unlike sex is reported, in which chromosomal analysis showed trisomy 21 in both of them, while the parental karyotypes were normal. This is the third reported case of such a constellation, and the second one in which infant and parental chromosomal analysis was done. Images PMID:6221105

  7. Single-twin demise: pregnancy outcome.

    PubMed

    Shek, Noel Wan Man; Hillman, Sarah C; Kilby, Mark D

    2014-02-01

    Single-twin demise can pose substantial risks for the surviving co-twin, including increased risk of fetal loss, preterm delivery, neurovascular injury, and end-organ damage. In this chapter, we summarise recently published research on the causes of single twin demise, the pathophysiology of injury to the surviving co-twin, and the evidence for current management strategies. The gestation at which single intrauterine fetal demise occurs, and the chorionicity of the multiple pregnancies, are the two most important factors when considering the risks to the surviving twin. Management should include fortnightly ultrasound scans for growth, umbilical artery Doppler studies, and liquor volume. In monochorionic twins, more complex Doppler assessment with middle cerebral artery Doppler velocimetry and a magnetic resonance imaging of the survivor's brain at least 3 weeks after single intrauterine fetal demise occurs should be carried out to look for evidence of neurological morbidity. With no other obstetric complications, dichorionic pregnancies can be delivered at term. Monochorionic pregnancies are more difficult to manage, and are often delivered between 34 and 36 weeks.

  8. Alloparenting for chimpanzee twins

    PubMed Central

    Kishimoto, Takeshi; Ando, Juko; Tatara, Seiki; Yamada, Nobuhiro; Konishi, Katsuya; Kimura, Natsuko; Fukumori, Akira; Tomonaga, Masaki

    2014-01-01

    In April 2009, a female chimpanzee named Sango, living in a captive group at the Noichi Zoo, Japan, gave birth to dizygotic male-female twin chimpanzees (male: Daiya, female: Sakura). The extent to which adult group members cared for the twins was investigated using a focal animal sampling method targeting six adults (one male) when the twin chimpanzees were two years old. Data were collected for an average of 6.78 h (SD = 0.79) per focal participant. An unaffiliated female adult of Sango was engaged in parenting Sakura as much as Sango. Given that Sakura was in lesser proximity to Sango than Daiya, Sakura's departures from her mother and her ability to gesture requests might have enabled non-kin adults to provide her care. PMID:25200656

  9. Twin-to-Twin Transfusion Syndrome

    PubMed Central

    Mahieu-Caputo, Dominique; Dommergues, Marc; Delezoide, Anne-Lise; Lacoste, Mireille; Cai, Yi; Narcy, Françoise; Jolly, Dominique; Gonzales, Marie; Dumez, Yves; Gubler, Marie-Claire

    2000-01-01

    The twin-to-twin transfusion syndrome (TTS) results from an unbalanced blood supply through placental anastomoses in monochorionic twins. It induces growth restriction, renal tubular dysgenesis, and oliguria in the donor and visceromegaly and polyuria in the recipient. A better understanding of its pathophysiology could contribute to improving the management of TTS, which still carries a high perinatal mortality in both twins. As well as several other candidates, the renin-angiotensin system might be involved in TTS. To evaluate its role in the pathogenesis of the syndrome, we studied the kidneys of 21 twin pairs who died from TTS at 19 to 30 weeks, compared with 39 individuals in a control group, using light microscopy, immunohistochemistry, and in situ hybridization. The overexpression of the renin protein and transcript with frequent evidence of renin synthesis by mesangial cells was observed in the donor kidneys, presumably as a consequence of chronic renal hypoperfusion. This upregulation of renin synthesis might be beneficial to restore euvolemia. In severe cases of TTS, however, angiotensin-II-induced vasoconstriction acts as an additional deleterious factor by further reducing the renal blood flow in donors. In recipients, renin expression was virtually absent, possibly because it was down-regulated by hypervolemia. However, in addition to congestion and hemorrhagic infarction, there were severe glomerular and arterial lesions resembling those observed in polycythemia- or hypertension-induced microangiopathy. We speculate that fetal hypertension in the recipient might be partly mediated by the transfer of circulating renin produced by the donor, through the placental vascular shunts. PMID:10666392

  10. '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

    2017-03-28

    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.

  11. Aortic and pulmonary artery calcification: An unusual manifestation of twin-to-twin transfusion syndrome

    PubMed Central

    Venkatesh, Sumitra; Sanyukta, J; Jain, S; Prabhu, SS; Kulkarni, S

    2017-01-01

    Twin-to-twin transfusion syndrome (TTTS) at times complicates monochorionic twin gestations, resulting in conditions ranging from discordant sizes to fetal demise of one baby. Various types of cardiac defects have been described in the recipient twin of this syndrome. Isolated great artery calcification, i.e. aortic and pulmonary artery calcification is one such uncommon condition associated with TTTS. Calcification of the walls of great vessels may be due to chronic vascular injury sustained as a result of circulatory volume overload in the recipient twin. It may also cause severe systemic hypertension and cardiomyopathy. An accurate diagnosis is important for an optimal follow-up and appropriate genetic counseling. We report a case of aortic and pulmonary artery calcification in association with TTTS. PMID:28163434

  12. Aortic and pulmonary artery calcification: An unusual manifestation of twin-to-twin transfusion syndrome.

    PubMed

    Venkatesh, Sumitra; Sanyukta, J; Jain, S; Prabhu, S S; Kulkarni, S

    2017-01-01

    Twin-to-twin transfusion syndrome (TTTS) at times complicates monochorionic twin gestations, resulting in conditions ranging from discordant sizes to fetal demise of one baby. Various types of cardiac defects have been described in the recipient twin of this syndrome. Isolated great artery calcification, i.e. aortic and pulmonary artery calcification is one such uncommon condition associated with TTTS. Calcification of the walls of great vessels may be due to chronic vascular injury sustained as a result of circulatory volume overload in the recipient twin. It may also cause severe systemic hypertension and cardiomyopathy. An accurate diagnosis is important for an optimal follow-up and appropriate genetic counseling. We report a case of aortic and pulmonary artery calcification in association with TTTS.

  13. Communicative Development in Twins with Discordant Histories of Recurrent Otitis Media.

    ERIC Educational Resources Information Center

    Hemmer, Virginia Hoey; Ratner, Nan Bernstein

    1994-01-01

    The communicative abilities of six sets of same-sex, preschool dizygotic twins were examined. In each dyad, one sibling had a strong history of recurrent otitis media (ROM) but the other twin did not. History of ROM was associated with lowered receptive vocabulary, with no consistent effects detected in expressive speech and language tasks.…

  14. Brief Report: On the Concordance Percentages for Autistic Spectrum Disorder of Twins

    ERIC Educational Resources Information Center

    Bohm, Henry V.; Stewart, Melbourne G.

    2009-01-01

    In the development of genetic theories of Autistic Spectrum Disorder (ASD) various characteristics of monozygotic (MZ) and dizygotic (DZ) twins are often considered. This paper sets forth a possible refinement in the interpretation of the MZ twin concordance percentages for ASD underlying such genetic theories, and, drawing the consequences from…

  15. Twin Study on Heritability of Activity, Attention, and Impulsivity as Assessed by Objective Measures

    ERIC Educational Resources Information Center

    Heiser, Philip; Heinzel-Gutenbrunner, Monika; Frey, Joachim; Smidt, Judith; Grabarkiewicz, Justyna; Friedel, Susann; Kuhnau, Wolfgang; Schmidtke, Jorg; Remschmidt, Helmut; Hebebrand, Johannes

    2006-01-01

    Objective: The purpose of this study was to assess heritability of activity, attention, and impulsivity by comparing young monozygotic (MZ) twins with dizygotic (DZ) twins using objective measures. Method: The OPTAx test is an infrared motion analysis to record the movement pattern during a continuous performance test. Seventeen MZ and 12 same…

  16. Utilizing twins as controls for non-twin case-materials in genome wide association studies.

    PubMed

    Ganna, Andrea; Ortega-Alonso, Alfredo; Havulinna, Aki; Salomaa, Veikko; Kaprio, Jaakko; Pedersen, Nancy L; Sullivan, Patrick F; Ingelsson, Erik; Hultman, Christina M; Magnusson, Patrik K E

    2013-01-01

    Twin registries around the globe have collected DNA samples from large numbers of monozygotic and dizygotic twins. The twin sample collections are frequently used as controls in disease-specific studies together with non-twins. This approach is unbiased under the hypothesis that twins and singletons are comparable in terms of allele frequencies; i.e. there are no genetic variants associated with being a twin per se. To test this hypothesis we performed a genome-wide association study comparing the allele frequency of 572,352 single nucleotide polymorphisms (SNPs) in 1,413 monozygotic (MZ) and 5,451 dizygotic (DZ) twins with 3,720 healthy singletons. Twins and singletons have been genotyped using the same platform. SNPs showing association with being a twin at P-value < 1 × 10(-5) were selected for replication analysis in 1,492 twins (463 MZ and 1,029 DZ) and 1,880 singletons from Finland. No SNPs reached genome-wide significance (P-value < 5 × 10(-8)) in the main analysis combining MZ and DZ twins. In a secondary analysis including only DZ twins two SNPs (rs2033541 close to ADAMTSL1 and rs4149283 close to ABCA1) were genome-wide significant after meta-analysis with the Finnish population. The estimated proportion of variance on the liability scale explained by all SNPs was 0.08 (P-value=0.003) when MZ and DZ were considered together and smaller for MZ (0.06, P-value=0.10) compared to DZ (0.09, P-value=0.003) when analyzed separately. In conclusion, twins and singletons can be used in genetic studies together with general population samples without introducing large bias. Further research is needed to explore genetic variances associated with DZ twinning.

  17. Prenatal diagnosis of spontaneous twin anemia-polycythemia sequence and postnatal examination of placental vascular anastomoses

    PubMed Central

    Bae, Jin Young; Oh, Jin Ju

    2016-01-01

    Twin anemia-polycythemia sequence (TAPS) is characterized by a wide discrepancy of hemoglobin between two monochorionic fetuses without sign of twin oligo-polyhydramnios sequence. A primiparous woman with monochorionic diamniotic twin transferred for preterm labor. Ultrasonographic evaluation at 32+3 weeks of gestation revealed increased middle cerebral artery-peak systolic velocity (77.4 cm/sec, 1.69 multiples of median) in donor and decreased in recipient twin (36.4 cm/sec, 0.79 multiples of median), the twin was diagnosed with TAPS. Repeated cesarean section was performed at 32+5 weeks of gestation following preeclampsia and preterm labor. After delivery, TAPS was confirmed through neonatal hematologic examination. There were no signs of acute hemorrhagic shock or brain injury. Placental evaluation via dye infusion and barium angiogram revealed one arterioarterial anastomoses with six arteriovenous anastomoses of placenta. We report a prenatally diagnosed case of spontaneous TAPS with arterioarterial and arteriovenous anastomoses and suggest careful monitoring of monochorionic twin and opinion on placenta vascular architecture. PMID:27896259

  18. Monozygotic twinning: an evolutionary hypothesis.

    PubMed Central

    Gleeson, S K; Clark, A B; Dugatkin, L A

    1994-01-01

    Monozygotic twinning is rare within populations yet taxonomically widespread. We explore the evolution of monozygotic twinning by modeling an allele in a newly formed offspring that causes it to undergo mitosis and separation to form one or more clones (twins), potentially in conflict with the parents' best interest. The success of this twinning allele in our haploid models depends on the balance of the benefit of increased frequency in the clutch and the cost of reduced survival resulting from limited parental resources. The trait reaches high frequency in a broad range of plausible conditions but also fails to spread or is kept at low frequency in others when the survival cost is high (e.g., in small clutch sizes). Interestingly, there are two reasonable conditions that predict high frequency of the trait but low visibility: random parental abortion and selection for low penetrance. Thus our models suggest reasons why monozygotic twinning might be rare, or alternatively, be common yet appear rare. In addition, we discuss the implications for sex-linked twinning, dizygotic twinning, and twinning by gametes. Images PMID:7972065

  19. Prospective risk of stillbirth and neonatal complications in twin pregnancies: systematic review and meta-analysis

    PubMed Central

    Cheong-See, Fiona; Schuit, Ewoud; Arroyo-Manzano, David; Khalil, Asma; Barrett, Jon; Joseph, K S; Asztalos, Elizabeth; Hack, Karien; Lewi, Liesbeth; Lim, Arianne; Liem, Sophie; Norman, Jane E; Morrison, John; Combs, C Andrew; Garite, Thomas J; Maurel, Kimberly; Serra, Vicente; Perales, Alfredo; Rode, Line; Worda, Katharina; Nassar, Anwar; Aboulghar, Mona; Rouse, Dwight; Thom, Elizabeth; Breathnach, Fionnuala; Nakayama, Soichiro; Russo, Francesca Maria; Robinson, Julian N; Dodd, Jodie M; Newman, Roger B; Bhattacharya, Sohinee; Tang, Selphee; Mol, Ben Willem J; Thilaganathan, Basky; Thangaratinam, Shakila

    2016-01-01

    Objective To determine the risks of stillbirth and neonatal complications by gestational age in uncomplicated monochorionic and dichorionic twin pregnancies. Design Systematic review and meta-analysis. Data sources Medline, Embase, and Cochrane databases (until December 2015). Review methods Databases were searched without language restrictions for studies of women with uncomplicated twin pregnancies that reported rates of stillbirth and neonatal outcomes at various gestational ages. Pregnancies with unclear chorionicity, monoamnionicity, and twin to twin transfusion syndrome were excluded. Meta-analyses of observational studies and cohorts nested within randomised studies were undertaken. Prospective risk of stillbirth was computed for each study at a given week of gestation and compared with the risk of neonatal death among deliveries in the same week. Gestational age specific differences in risk were estimated for stillbirths and neonatal deaths in monochorionic and dichorionic twin pregnancies after 34 weeks’ gestation. Results 32 studies (29 685 dichorionic, 5486 monochorionic pregnancies) were included. In dichorionic twin pregnancies beyond 34 weeks (15 studies, 17 830 pregnancies), the prospective weekly risk of stillbirths from expectant management and the risk of neonatal death from delivery were balanced at 37 weeks’ gestation (risk difference 1.2/1000, 95% confidence interval −1.3 to 3.6; I2=0%). Delay in delivery by a week (to 38 weeks) led to an additional 8.8 perinatal deaths per 1000 pregnancies (95% confidence interval 3.6 to 14.0/1000; I2=0%) compared with the previous week. In monochorionic pregnancies beyond 34 weeks (13 studies, 2149 pregnancies), there was a trend towards an increase in stillbirths compared with neonatal deaths after 36 weeks, with an additional 2.5 per 1000 perinatal deaths, which was not significant (−12.4 to 17.4/1000; I2=0%). The rates of neonatal morbidity showed a consistent reduction with increasing

  20. Peer Network Overlap in Twin, Sibling, and Friend Dyads

    ERIC Educational Resources Information Center

    McGuire, Shirley; Segal, Nancy L.

    2013-01-01

    Research suggests that sibling–peer connections are important for understanding adolescent problem behaviors. Using a novel behavioral genetic design, the current study investigated peer network overlap in 300 child–child pairs (aged 7-13 years) in 5 dyad types: monozygotic (MZ), dizygotic twins, full siblings (FSs), friend pairs, and virtual…

  1. NOTE: Thrombosis of anastomoses may affect the staging sequence of twin twin transfusion syndrome

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

    Twin-twin transfusion syndrome (TTTS) is a severe complication of monozygotic (identical) twins, which share one single monochorionic placenta. It is caused by placental anastomoses which link the two fetoplacental circulations of the twins and allow a chronic net inter-twin transfusion to develop between the fetuses. Clinical presentation of TTTS manifestations has been classified into five different stages. In this paper, we used our computational model of TTTS and examined the possible differences between chronic and rapidly increasing inter-twin transfusion in the simulated TTTS staging sequence. Our results suggest that rapid alterations in the net inter-twin transfusion, e.g. due to thrombosis of placental anastomoses, may produce a different staging sequence than in TTTS caused by chronic inter-twin transfusion. These results may aid an improved knowledge of TTTS pathophysiology under conditions of a rapidly changing cardiovascular function, and contribute to the planning of optimal intervention under such circumstances. Supported in part by the European Community Euro-twin-2-twin project (JPHMvdW) and by the National Institutes of Health, grant HL40899 (MGR).

  2. Twin-twin transfusion syndrome presenting as polyhydramnios in both fetuses secondary to spontaneous microseptostomy.

    PubMed

    Hackney, David N; Khalek, Nahla; Moldenhauer, Julie; Ozcan, Tulin

    2013-10-01

    The presence of polyhydramnios and oligohydramnios is pathognomonic for twin-twin transfusion syndrome (TTTS). However, polyhydramnios of both twins can exist in TTTS in the setting of a septostomy of the dividing membrane. In prior reported cases of dual polyhydramnios TTTS, the septostomy was identified through either ultrasound or fetoscopy thus helping to establish the diagnosis of TTTS with an unusual presentation. The presented case is a set of monochorionic, diamniotic twins who presented initially with dual polyhydramnios. Subsequent ultrasound and clinical and pathologic findings were otherwise consistent with TTTS. Unlike prior reported cases, a septostomy of the dividing membrane was never identified with ultrasound or even on post delivery placental examination. However, microseptostomies were demonstrated due to the transfer of indigo carmine between the amniotic sacs at amniocentesis. Thus in the setting of TTTS concern, the diagnosis should be considered with dual polyhydramnios even if a septostomy cannot be identified.

  3. Gestational age in twins.

    PubMed Central

    James, W H

    1980-01-01

    Dubowitz et al. have offered a scoring system for estimating the gestational age of newborn babies. If the system is applied to twin pairs, the heavier twin is generally estimated to have a greater gestational age than the lighter one. Previously this has been interpreted as a flaw in the scoring system. However, it may well be that in some twin pairs the gestational ages are slightly different and that therefore, the heavier twin would be expected to have a greater gestational age. Such cases would arise through superfecundation (the formation of two zygotes from different coitions). Superfecundation can be proved only in rare case (those with two fathers). It can be argued that the rarity of such cases is accounted for by the rarity with which women expose themselves to the risk of bearing such twins (and by the improbability of detection), rather than by the rarity of superfecundation. It is inferred that superfecundation by the same man is relatively common and that therefore dizygotic twins quite often have different gestational ages. The scoring system of Dubowitz can be tested for bias by submitting monozygotic pairs to it: the association between weight and estimated gestational age should be absent in such pairs. If the system proves free of such bias, then a finding first reported here will assume some interest: it is that in opposite-sexed twin pairs, the male is significantly more often assessed as having the greater gestational age. It is suggested that this finding should be provisionally accepted as evidence for the hyopthesis that male zygotes are formed earlier than females. PMID:7191240

  4. 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.

  5. Twin-to-twin transfusion syndrome: an anti-angiogenic state?

    PubMed Central

    KUSANOVIC, Juan Pedro; ROMERO, Roberto; ESPINOZA, Jimmy; NIEN, Jyh Kae; KIM, Chong Jai; MITTAL, Pooja; EDWIN, Sam; EREZ, Offer; GOTSCH, Francesca; MAZAKI-TOVI, Shali; THAN, Nandor G.; SOTO, Eleazar; CAMACHO, Natalia; GOMEZ, Ricardo; QUINTERO, Ruben; HASSAN, Sonia S.

    2008-01-01

    Objective An imbalanced chronic blood flow between the donor and recipient twin through placental vascular anastomoses is the accepted pathophysiology of twin-to-twin transfusion syndrome (TTTS). Vascular endothelial growth factor receptor-1 (VEGFR-1) mRNA is overexpressed only in the syncytiotrophoblast of the donor twin in some cases of TTTS. This study was conducted to determine maternal plasma concentrations of placental growth factor (PlGF), soluble VEGFR-1, and soluble endoglin (s-Eng) in monochorionic-diamniotic pregnancies with and without TTTS. Study design This case-control study included monochorionic-diamniotic pregnancies between 16–26 weeks with and without TTTS. Maternal plasma concentrations of PlGF, sVEGFR-1 and s-Eng were determined with ELISA. A p-value <.05 was considered statistically significant. Results Patients with TTTS had higher median plasma concentrations of s-Eng [14.8 ng/ml vs. 7.8 ng/ml; p<0.001] and sVEGFR-1 [6383.1 pg/ml vs. 3220.1 pg/ml; p<0.001]; and lower median plasma concentrations of PlGF [115.5 pg/ml vs. 359.3 pg/ml; p=0.002] than those without TTTS. Conclusions We propose that an anti-angiogenic state may be present in some cases of TTTS. PMID:18395032

  6. Dichorionic triamniotic triplet pregnancy complicated by twin anemia polycythemia sequence: the place of fetal therapy.

    PubMed

    Griersmith, Thérèse H; Fung, Alison M; Walker, Susan P

    2014-12-01

    Monochorionic twins as part of a high order multiple pregnancy can be an unintended consequence of the increasingly common practice of blastocyst transfer for couples requiring in vitro fertilisation (IVF) for infertility. Dichorionic triamniotic (DCTA) triplets is the most common presentation, and these pregnancies are particularly high risk because of the additional risks associated with monochorionicity. Surveillance for twin-to-twin transfusion syndrome, including twin anemia polycythemia sequence, may be more difficult, and any intervention to treat the monochorionic pair needs to balance the proposed benefits against the risks posed to the unaffected singleton. Counseling of families with DCTA triplets is therefore complex. Here, we report a case of DCTA triplets, where the pregnancy was complicated by threatened preterm labour, and twin anemia polycythemia sequence (TAPS) was later diagnosed at 28 weeks. The TAPS was managed with a single intraperitoneal transfusion, enabling safe prolongation of the pregnancy for over 2 weeks until recurrence of TAPS and preterm labour supervened. Postnatal TAPS was confirmed, and all three infants were later discharged home at term corrected age, and were normal at follow-up. This case highlights that in utero therapy has an important role in multiple pregnancies of mixed chorionicity, and can achieve safe prolongation of pregnancy at critical gestations.

  7. Inspection Time and Cognitive Abilities in Twins Aged 7 to 17 Years: Age-Related Changes, Heritability and Genetic Covariance

    ERIC Educational Resources Information Center

    Edmonds, Caroline J.; Isaacs, Elizabeth B.; Visscher, Peter M.; Rogers, Mary; Lanigan, Julie; Singhal, Atul; Lucas, Alan; Gringras, Paul; Denton, Jane; Deary, Ian J.

    2008-01-01

    We studied the age-related differences in inspection time and multiple cognitive domains in a group of monozygotic (MZ) and dizygotic (DZ) twins aged 7 to 17 years. Data from 111 twin pairs and 19 singleton siblings were included. We found clear age-related trends towards more efficient visual information processing in older participants. There…

  8. Chorion type as a possible influence on the results and interpretation of twin study data.

    PubMed

    Prescott, C A; Johnson, R C; McArdle, J J

    1999-12-01

    The estimation of genetic effects from twin studies usually relies upon the equal environment assumption--that monozygous (MZ) and dizygous (DZ) twin pairs experience equal similarity of their environments from prenatal experiences through adulthood. However, the sharing of a chorion may make a subset of identical twins more similar, or in some cases, more different, than twins that do not share a chorion. Recent studies suggest monochorionic MZ twins resemble one another more than dichorionic MZ twins in cognitive abilities, personality, and risk for psychiatric disorder. To the extent that prenatal environment affects these characteristics, the traditional twin method will yield biased estimates of genetic and environmental influences. We develop models for quantifying this bias and estimating the influence of chorion type on estimates of heritability.

  9. Twin anemia-polycythemia sequence in a case of monoamniotic twins.

    PubMed

    Diehl, W; Glosemeyer, P; Tavares De Sousa, M; Hollwitz, B; Ortmeyer, G; Hecher, K

    2013-07-01

    Twin anemia-polycythemia sequence (TAPS) complicates up to 6% of monochorionic diamniotic twin pregnancies, typically in the late second or third trimester. The presence of only a few and very small arteriovenous vascular anastomoses characterizes the underlying angioarchitecture at the chorionic plate in cases of TAPS. In monoamniotic twins, large vascular anastomoses can usually be seen at the placental vascular equator, and therefore one would not expect the development of TAPS in monoamniotic twins. We report a case of TAPS in a monoamniotic pregnancy at 26 + 5 weeks' gestation which responded favorably to fetoscopic laser coagulation of the small placental anastomoses, resolving severe anemia in one twin and polycythemia in the other. The pregnancy continued until 32 + 5 weeks, when worsening cord entanglement with increased resistance and the development of postsystolic notches in the umbilical artery of one twin prompted delivery by Cesarean section. There was only a moderate difference in neonatal hemoglobin concentrations, with the former polycythemic twin needing a single partial volume exchange transfusion. The postnatal course of the neonates was uneventful, according to their gestational age at birth. To our knowledge this is the first case report describing successful laser therapy for TAPS in monoamniotic twins.

  10. Disease-Concordant Twins Empower Genetic Association Studies.

    PubMed

    Tan, Qihua; Li, Weilong; Vandin, Fabio

    2017-01-01

    Genome-wide association studies with moderate sample sizes are underpowered, especially when testing SNP alleles with low allele counts, a situation that may lead to high frequency of false-positive results and lack of replication in independent studies. Related individuals, such as twin pairs concordant for a disease, should confer increased power in genetic association analysis because of their genetic relatedness. We conducted a computer simulation study to explore the power advantage of the disease-concordant twin design, which uses singletons from disease-concordant twin pairs as cases and ordinary healthy samples as controls. We examined the power gain of the twin-based design for various scenarios (i.e., cases from monozygotic and dizygotic twin pairs concordant for a disease) and compared the power with the ordinary case-control design with cases collected from the unrelated patient population. Simulation was done by assigning various allele frequencies and allelic relative risks for different mode of genetic inheritance. In general, for achieving a power estimate of 80%, the sample sizes needed for dizygotic and monozygotic twin cases were one half and one fourth of the sample size of an ordinary case-control design, with variations depending on genetic mode. Importantly, the enriched power for dizygotic twins also applies to disease-concordant sibling pairs, which largely extends the application of the concordant twin design. Overall, our simulation revealed a high value of disease-concordant twins in genetic association studies and encourages the use of genetically related individuals for highly efficiently identifying both common and rare genetic variants underlying human complex diseases without increasing laboratory cost.

  11. Evidence for higher heritability of somatotype compared to body mass index in female twins.

    PubMed

    Reis, Victor Machado; Machado, João V; Fortes, Marcos S; Fernandes, Paula Roquetti; Silva, António José; Dantas, Paulo Silva; Filho, José Fernandes

    2007-01-01

    The influence of genetics on human physique and obesity has been addressed by the literature. Evidence for heritability of anthropometric characteristics has been previously described, mainly for the body mass index (BMI). However, few studies have investigated the influence of genetics on the Heath-Carter somatotype. The aim of the present study was to assess the heritability of BMI and somatotype (endomorphy, mesomorphy, and ectomorphy) in a group of female monozygotic and dizygotic twins from childhood to early adulthood. A total of 28 females aged from 7 to 19 years old were studied. The group included 5 monozygotic and 9 dizygotic pairs of twins. The heritability was assessed by the twin method (h(2)). The anthropometric measures and somatotype were assessed using standard validated procedures. Significant differences between monozygotic and dizygotic pairs of twins were found for height, endomorphy, ectomorphy, and mesomorphy, and the heritability for these measures was high (h(2) between 0.88 and 0.97). No significant differences were found between monozygotic and dizygotic twins for weight, and the BMI and the heritability indexes were lower for these measures (respectively 0.42 and 0.52). The results of the present study have indicated that the somatotype may be more sensible to genetic influences than the BMI in females.

  12. Minimally Conjoined Omphalopagus Twins with a Body Stalk Anomaly

    PubMed Central

    Maruyama, Hidehiko; Inagaki, Takeshi; Nakata, Yusei; Kanazawa, Akane; Iwasaki, Yuka; Sasaki, Kiyoshi; Nagai, Ryuhei; Kinoshita, Hiromi; Iwata, Jun; Kikkawa, Kiyoshi

    2015-01-01

    Introduction This report will discuss a case of minimally conjoined omphalopagus twins (MCOTs) with a body stalk anomaly (BSA). Case Report We experienced monochorionic diamniotic (MD) twins born at 31 weeks. One infant was suspicious of BSA before birth, and another infant was normal. But normal infant had anal atresia with small intestine which was inserted behind the umbilicus. Twins had very short common umbilicus and infant with BSA had intestinal conjunction, two appendixes at the site of the colon, and a blind-ending colon. We diagnosed MCOTs. Discussion On the basis of the Spencer hypothesis, the etiology of MCOTs was that MD twins shared a yolk sac. However, this could not explain the presence of a BSA. It is necessary to consider the possible reasons for a singleton BSA. In addition, intestinal fusion occurred unequally in this case, although two appendixes were found in the same place, which might have occurred because of the balanced fusion. PMID:26495169

  13. Imperfect twinning: a clinical and ethical dilemma

    PubMed Central

    Denardin, Daniela; Telles, Jorge Alberto B.; Betat, Rosilene da Silveira; Fell, Paulo Renato K.; da Cunha, André Campos; Targa, Luciano Vieira; Zen, Paulo Ricardo G.; Rosa, Rafael Fabiano M.

    2013-01-01

    OBJECTIVE To review the history, epidemiology, etiology, gestational aspects, diagnosis and prognosis of imperfect twinning. DATA SOURCES Scientific articles were searched in PubMed, SciELO and Lilacs databases, using the descriptors "conjoined twins", "multiple pregnancy", "ultrasound", "magnetic resonance imaging" and "prognosis". The research was not delimited to a specific period of time and was supplemented with bibliographic data from books. DATA SYNTHESIS: The description of conjoined twins is legendary. The estimated frequency is 1/45,000-200,000 births. These twins are monozygotic, monochorionic and usually monoamniotic. They can be classified by the most prominent fusion site, by the symmetry between the conjoined twins or by the sharing structure. The diagnosis can be performed in the prenatal period or after birth by different techniques, such as ultrasound, magnetic resonance imaging and echocardiography. These tests are of paramount importance for understanding the anatomy of both fetuses/children, as well as for prognosis and surgical plan determination. CONCLUSIONS Although imperfect twinning is a rare condition, the prenatal diagnosis is very important in order to evaluate the fusion site and its complexity. Hence, the evaluation of these children should be multidisciplinary, involving mainly obstetricians, pediatricians and pediatric surgeons. However, some decisions may constitute real ethical dilemmas, in which different points should be discussed and analyzed with the health team and the family. PMID:24142323

  14. Fetal Cholelithiasis: Antenatal Diagnosis and Neonatal Follow-Up in a Case of Twin Pregnancy – A Case Report and Review of the Literature

    PubMed Central

    Hurni, Yannick; Vigo, Francesco; von Wattenwyl, Begoña Lipp; Ochsenbein, Nicole; Canonica, Claudia

    2017-01-01

    Fetal cholelithiasis is a rare finding during a third-trimester ultrasound with an average incidence rate of 0.07–1.15%. We report a case of fetal cholelithiasis in twins, observed in a patient with monochorionic diamniotic twin pregnancy hospitalized at our unit for signs of premature labor. We present the outcome of the 2 neonates with a clinical and sonographic follow-up. In addition, we offer a comprehensive review of the literature available to date. PMID:28210714

  15. Head circumferences in twins with and without Autism Spectrum Disorders.

    PubMed

    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

    2013-09-01

    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 % of females with an ASD had macrocephaly. Unaffected co-twins showed similar rates (16 % of males and 22 % of females). Statistical analysis revealed no significant difference in HCs between affected and unaffected twins. Twins with ASDs and unaffected co-twins have similar HCs and increased rates of macrocephaly. Correlations demonstrated partial inheritance of HCs. Thus, macrocephaly may represent an endophenotype in ASDs.

  16. Sensory Motor and Functional Skills of Dizygotic Twins: One with Smith-Magenis Syndrome and a Twin Control

    ERIC Educational Resources Information Center

    Smith, Michaele R.; Hildenbrand, Hanna; Smith, Ann C. M.

    2009-01-01

    Smith-Magenis syndrome (SMS), the result of an interstitial deletion within chromosome 17p11.2, is a disorder that may include minor dysmorphic features, brachydactyly, short stature, hypotonia, speech delays, cognitive deficits, signs of peripheral neuropathy, scoliosis, and neurobehavioral problems including sleep disturbances and maladaptive…

  17. Longitudinal Twin Study of Early Literacy Development: Preschool and Kindergarten Phases

    ERIC Educational Resources Information Center

    Byrne, Brian; Wadsworth, Sally; Corley, Robin; Samuelsson, Stefan; Quain, Peter; DeFries, John C.; Willcutt, Erik; Olson, Richard K.

    2005-01-01

    We conducted behavior?genetic analyses of kindergarten reading, spelling, phonological awareness, rapid naming, and spoken sentence processing in 172 pairs of monozygotic and 153 pairs of same-sex dizygotic twin kindergarten children sampled in the United States and Australia. We also modeled progress from preschool to kindergarten in…

  18. Genetic and environmental effects on the bone development of the hand and wrist in Chinese young twins.

    PubMed

    Dong, Li Yan; Tan, Ji Bin; Zhao, Jing Lan; Jiang, Fa Chun; Tian, Xiao Cao; Ning, Feng; Wang, Shao Jie; Zhang, Dong Feng; Pang, Zeng Chang; Zhao, Zhong Tang

    2015-03-01

    We assessed genetic and environmental effects on bone development of the hand and wrist, and on key anthropometric measures in Chinese young twins. In total, 139 monozygotic and 95 dizygotic twin pairs aged from 5 to 18 years were recruited. The twin correlations of total hand and wrist scores for monozygotic (MZ) and dizygotic (DZ) twins were 0.71 and 0.36, respectively. Bivariate model analysis showed moderate genetic correlations only for total skeletal maturity vs. weight and total skeletal maturity vs. waist circumference (r, 0.51 and 0.46, respectively). Our findings demonstrated that genetic factors played important roles in bone development of the hand and wrist in Chinese young twins, and that these genetic effects might be distinct from those influencing anthropometric measures.

  19. Starry sky pattern of fetal liver sonogram as first sign of twin-twin transfusion syndrome.

    PubMed

    Segev, Y; Goldberg, Y; Riskin-Mashiah, S; Berdicef, M; Lavie, O; Auslender, R

    2012-06-01

    'Starry sky' liver is one of the most common sonographic patterns in diffuse liver disease. It is characterized by clearly identified portal venules due to diminished parenchymal echogenicity. In advanced cases of twin-to-twin transfusion syndrome (TTTS), volume overload is considered the key factor in the pathogenesis of cardiac dysfunction of the recipient twin. When right-sided failure occurs, the liver might show signs of edema and, as in acute hepatitis, the appearance of starry sky might develop. We present a case in which the sonographic appearance of starry sky liver, along with right-sided cardiac failure (tricuspid regurgitation), were the first signs of TTTS in monochorionic twins at 20 weeks. A short time later, at 21 weeks, other signs of overload and signs of worsening heart failure were noted, as the typical triphasic waves in the inferior vena cava were replaced by a biphasic flow profile. Twin 2 at that time had relative oligohydramnios. A few days later, relative polyhydramnios and edema of the placental domain of the recipient twin were also noted. To the best of our knowledge, this is the first case report describing this hepatic sonographic pattern as an early sonographic sign of TTTS.

  20. Methylation matters? Decreased methylation status of genomic DNA in the blood of schizophrenic twins.

    PubMed

    Bönsch, Dominikus; Wunschel, Michael; Lenz, Bernd; Janssen, Gesa; Weisbrod, Matthias; Sauer, Heinrich

    2012-08-15

    Studies of schizophrenia inheritance in identical twins show a concordance of about 50%, which supports an epigenetic model. In our present study we investigated methylation of genomic DNA and promoter methylation of Reelin and SOX10 genes in peripheral blood of twins suffering from schizophrenia. Global DNA methylation was reduced (52.3%) in schizophrenic twins if compared with healthy control twins (65.7%). The reduced methylation was significant in males only. We also found a similar hypomethylation in the non-affected twins of discordant pairs and a mixed group of psychiatric controls. In discordant twins there was a relative hypermethylation of the SOX10 promoter. Within-pair-difference of methylation of Reelin promoter was significantly lower in monozygotic twins than in dizygotic twins.

  1. Twins discordant for myositis and systemic lupus erythematosus show markedly enriched autoantibodies in the affected twin supporting environmental influences in pathogenesis

    PubMed Central

    2014-01-01

    Background Studies of twin pairs discordant for autoimmune conditions provide a unique opportunity to explore contributing factors triggered by complex gene-environment interactions. Methods In this cross-sectional study, thirty-one monozygotic or dizygotic twin pairs discordant for myositis or systemic lupus erythematosus (SLE), along with matched healthy controls were evaluated for antibodies against a panel of 21 autoantigens. Results Autoantibody profiling revealed that 42% of the affected twins showed significant seropositivity against autoantigens in the panel. In many of these affected twins, but none of healthy controls, there were high levels of autoantibodies detected against two or more autoantigens commonly seen in systemic autoimmune diseases including Ro52, Ro60, RNP-70 K and/or RNP-A. In contrast, only 10% (3/31) of the unaffected twins showed seropositivity and these immunoreactivities were against single autoantigens not seen in systemic autoimmune diseases. While no significant differences in autoantibodies were detected between the affected or unaffected twins against thyroid peroxidase, transglutaminase and several cytokines, 23% of the affected twins with myositis showed autoantibodies against the gastric ATPase. Analysis of the monozygotic twins separately also revealed a higher frequencies of autoantibodies in the affected twins compared to the unaffected twins (P = 0.046). Lastly, clinical analysis of both the affected monozygotic and dizygotic twins revealed that the autoantibody seropositive affected twins had a greater global disease activity score compared to seronegative affected twins (P = 0.019). Conclusion The findings of significantly more autoantibodies in the affected twins with myositis and SLE compared to the unaffected twins are consistent with potential non-genetic factors playing a role in autoantibody production and pathogenesis of these autoimmune disorders. PMID:24602337

  2. 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.

  3. Acardiac twin pregnancy: successful intrauterine ablative treatment with alcohol at 14 weeks of gestation.

    PubMed

    Guven, M A; Koc, O; Bodur, H; Erkanli, S; Bagis, T; Usal, D

    2016-01-01

    Twin reversed arterial perfusion (TRAP) sequence is a serious condition of monochorionic twin pregnancy, occurring in approximately one in 35,000 cases. First trimester treatment of TRAP sequence is controversial with higher incidence of procedure related complications. Present case demonstrates a TRAP sequence that was managed by intrauterine treatment with one-ml 100% pure alcohol injection into the abdominal part of the umbilical artery and obliteration of the acardiac twin at 14 weeks of gestation. Antenatal follow-up was uneventful and elective cesarean section was performed at 39 weeks' gestation. Postnatal outcome of the pump twin was excellent at 30 months after birth. Early second trimester elective ablation by alcohol injection can be an inexpensive, alternative, and reasonable minimal invasive treatment option to prevent fetal loss of pump twin before mid and late second trimester in perinatology centers where intrafetal cord occlusive methods are not available.

  4. Current twin studies in Germany: report on CoSMoS, SOEP, and ChronoS.

    PubMed

    Hahn, Elisabeth; Gottschling, Juliana; Spinath, Frank M

    2013-02-01

    This article summarizes the status of three recent German twin studies: CoSMoS, SOEP, and ChronoS. The German twin study on Cognitive Ability, Self-Reported Motivation, and School Achievement (CoSMoS) is a three-wave longitudinal study of monozygotic and dizygotic twins reared together, and aims to investigate predictors of and influences on school performance. In the first wave of the data collection in 2005, 408 pairs of twins aged between 7 and 11 as well as their parents participated in CoSMoS. The SOEP twin study is an extended twin study, which has combined data from monozygotic and dizygotic twins reared together with additional data from full sibling pairs, mother-child, and grandparent-child dyads who participated in the German Socio-Economic Panel (GSOEP) study. The SOEP twin project comprises about 350 twin and 950 non-twin pairs aged between 17 and 70. Data were collected between 2009 and 2010, with a focus on personality traits, wellbeing, education, employment, income, living situation, life-satisfaction, and several attitudes. The aim of the Chronotype twin study (ChronoS) was to examine genetic and environmental influences on chronotype (morningness and eveningness), coping strategies, and several aspects of the previous SOEP twin project in a sample of 301 twin pairs aged between 19 and 76 years, recruited in 2010 and 2011. Part of the ChronoS twin sample also participated in the earlier SOEP twin study, representing a second wave of assessments. We briefly describe the design and contents of these three studies as well as selected recent findings.

  5. Erythroblastosis of the Donor Twin of Twin Anemia-Polycythemia Sequence.

    PubMed

    Takeuchi, Miharu; Maruyama, Hidehiko; Oura, Naoko; Kanazawa, Akane; Nakata, Yusei; Minami, Susumu; Kikkawa, Kiyoshi

    2016-08-01

    Twin anemia-polycythemia sequence (TAPS) is a group of disorders in monochorionic twins characterized by a large intertwin hemoglobin difference without amniotic fluid discordance. Reticulocyte count is used to diagnose this condition, but little is known about the role of erythroblasts, which are the prior stage of reticulocytes. In the present case of TAPS, the 25-yr-old Japanese mother showed no signs of oligohydramnios or polyhydramnios throughout gestation. The twins were born at 36 weeks and 6 days, weighing 2,648g and 1,994g. The intertwin hemoglobin difference in umbilical cord blood was (21.1-5.0=) 16.1g/dL and the donor twin showed signs of chronic anemia, including myocardial hypertrophy and pericardial effusion. Erythroblastosis of the donor twin was prolonged (53,088.5, 42,114.8 and 44,217.9/μL on days 0, 1 and 2, respectively). Erythroblastosis, which indicates chronic anemia, is also a good diagnostic indicator of TAPS.

  6. Symptomatic colloid cysts in the third ventricle of monozygotic twins

    PubMed Central

    Popek, Edith

    2015-01-01

    In this case report we describe colloid cysts in the third ventricles of monozygotic twin sisters. They were 26 years old when their condition was discovered. One woman was admitted to us on an emergency basis, with signs of high intracranial pressure such as unconsciousness and extension posturing. Her sister was also brought to the hospital since she had a history of attacks of headache. They were both operated with removal of the colloid cysts, and the clinical courses are described in the case report. In reviewing the literature another 30 familial cases were found. Of these were two pairs of monozygotic and one pair of dizygotic twins. PMID:25491677

  7. Genetic and environmental contributions to pro-social attitudes: a twin study of social responsibility.

    PubMed Central

    Rushton, J. Philippe

    2004-01-01

    Although 51 twin and adoption studies have been performed on the genetic architecture of antisocial behaviour, only four previous studies have examined a genetic contribution to pro-social behaviour. Earlier work by the author with the University of London Institute of Psychiatry Adult Twin Register found that genes contributed approximately half of the variance to measures of self-report altruism, empathy, nurturance and aggression, including acts of violence. The present study extends those results by using a 22-item Social Responsibility Questionnaire with 174 pairs of monozygotic twins and 148 pairs of dizygotic twins. Forty-two per cent of the reliable variance was due to the twins' genes, 23% to the twins' common environment and the remainder to the twins' non-shared environment. PMID:15615684

  8. A twin study of computer anxiety in Turkish adolescents.

    PubMed

    Deryakulu, Deniz; Calışkan, Erkan

    2012-04-01

    The present study investigated computer anxiety within a sample of Turkish twins aged 10-18. A total of 185 twin-pairs participated in the study. Of the twins, 64 pairs (34.6 percent) were monozygotic (MZ) and 121 pairs (65.4 percent) were dizygotic (DZ). Of the 121 DZ twins, 54 pairs (44.63 percent) were same-sex twins and 67 pairs (55.37 percent) were opposite-sex twins. Computer anxiety was assessed using Computer Anxiety Rating Scale-Turkish Version (CARS-TV), one of the three main scales of "Measuring Technophobia Instruments" developed by Rosen and Weil. The results of paired t test comparisons showed no significant differences in MZ and same-sex DZ twin-pairs' levels of computer anxiety. On the other hand, a significant difference was found in opposite-sex DZ twin-pairs' level of computer anxiety. Interesting enough, males appeared to be more computer anxious than their female co-twins. In the present study, using Falconer's formula, heritability estimate for computer anxiety was derived from correlations based on MZ and DZ twins' mean scores on CARS-TV. The results showed that 57 percent of the variance in computer anxiety was from genetics and 41.5 percent was from nonshared environmental factors. Shared environmental influence, on the other hand, was very small and negligible. Interpretations of results and potential directions for future research are presented.

  9. Genetic Heritability and Shared Environmental Factors Among Twin Pairs With Autism

    PubMed Central

    Hallmayer, Joachim; 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.; Risch, Neil

    2015-01-01

    Context Autism is considered the most heritable of neurodevelopmental disorders, mainly because of the large difference in concordance rates between monozygotic and dizygotic twins. Objective To provide rigorous quantitative estimates of genetic heritability of autism and the effects of shared environment. Design, Setting, and Participants Twin pairs with at least 1 twin with an autism spectrum disorder (ASD) born between 1987 and 2004were identified through the California Department of Developmental Services. Main Outcome Measures Structured diagnostic assessments (Autism Diagnostic Interview–Revised and Autism Diagnostic Observation Schedule) were completed on 192 twin pairs. Concordance rates were calculated and parametric models were fitted for 2 definitions, 1 narrow (strict autism) and 1 broad (ASD). Results For strict autism, probandwise concordance for male twins was 0.58 for 40 monozygotic pairs (95% confidence interval [CI], 0.42–0.74) and 0.21 for 31 dizygotic pairs (95% CI, 0.09–0.43); for female twins, the concordance was 0.60 for 7 monozygotic pairs (95% CI, 0.28–0.90) and 0.27 for 10 dizygotic pairs (95% CI, 0.09–0.69). For ASD, the probandwise concordance for male twins was 0.77 for 45 monozygotic pairs (95% CI, 0.65–0.86) and 0.31 for 45 dizygotic pairs (95% CI, 0.16–0.46); for female twins, the concordance was 0.50 for 9 monozygotic pairs (95% CI, 0.16–0.84) and 0.36 for 13 dizygotic pairs (95% CI, 0.11–0.60). A large proportion of the variance in liability can be explained by shared environmental factors (55%; 95% CI, 9%–81% for autism and 58%; 95% CI, 30%–80% for ASD) in addition to moderate genetic heritability (37%; 95% CI, 8%–84% for autism and 38%; 95% CI, 14%–67% for ASD). Conclusion Susceptibility to ASD has moderate genetic heritability and a substantial shared twin environmental component. PMID:21727249

  10. Influences on achieving motor milestones: a twin-singleton study.

    PubMed

    Brouwer, Silvia I; van Beijsterveldt, Toos C E M; Bartels, Meike; Hudziak, James J; Boomsma, Dorret I

    2006-06-01

    In order to determine if twinning impacted achievement of motor milestones the attainment of early motor milestones in twins was examined and compared to published data from singletons of the same age from the same culture and birth years. We examined the influence of twinning, sex, zygosity and birth cohort (1987-2001) on the motor development of twins aged 0 to 24 months. Data on the attainment of motor milestones (turn, sit, crawl, stand and walk) of twins were collected from maternal reports. All data were corrected for gestational age. Data from the twin sample were compared to normative data from singletons, which were available from Child Health Clinics (CHC). Analyses across twin data and the CHC singleton data revealed no differences between twins and singletons in achievement of motor milestones. Girls were able to sit without support slightly earlier than boys, otherwise there were no other sex differences. Birth-order analyses revealed minimal but significant differences in turning over from back to belly and for sitting without support between the first- and second-born. Dizygotic (DZ) twins were faster than monozygotic (MZ) twins in achieving the moment of sit, crawl, stand and walk. Twins born in earlier cohorts were faster in reaching the moment of crawl, sit and walk. It is concluded that there are no differences in time of reaching motor milestones between twins and singletons within the normal range. Sex has minimal to no effect on motor development in early childhood. DZ twins achieve motor milestones sooner than MZ twins. Attainment of gross motor milestones (crawl, stand and walk) is delayed in later birth cohorts.

  11. Why Accurate Knowledge of Zygosity is Important to Twins.

    PubMed

    Cutler, Tessa L; Murphy, Kate; Hopper, John L; Keogh, Louise A; Dai, Yun; Craig, Jeffrey M

    2015-06-01

    All same-sex dizygotic (DZ) twins and approximately one-third of monozygotic (MZ) twin pairs have separate placentas, making it impossible to use the number of placentas to determine zygosity. Zygosity determination is further complicated because incorrect assumptions are often made, such as that only DZ pairs have two placentas and that all MZ pairs are phenotypically identical. These assumptions, by twins, their families and health professionals, along with the lack of universal zygosity testing for same-sex twins, has led to confusion within the twin community, yet little research has been conducted with twins about their understanding and assumptions about zygosity. We aimed to explore and quantify understanding and assumptions about zygosity using twins attending an Australian twin festival. We recruited 91 twin pairs younger than 18 years of age and their parents, and 30 adult twin pairs who were all uncertain of their zygosity, to complete one pen and paper questionnaire and one online questionnaire about their assumed zygosity, reasons for their assumptions and the importance of accurate zygosity knowledge. Responses were compared with their true zygosity measured using a genetic test. We found a substantial proportion of parents and twins had been misinformed by their own parents or medical professionals, and that knowledge of their true zygosity status provided peace of mind and positive emotional responses. For these reasons we propose universal zygosity testing of same-sex twins as early in life as possible and an increase in education of medical professionals, twins and families of twins about zygosity issues.

  12. Twins born following fertility treatment: implications for quantitative genetic studies.

    PubMed

    Goody, Adam; Rice, Frances; Boivin, Jacky; Harold, Gordon T; Hay, Dale F; Thapar, Anita

    2005-08-01

    The rate of multiple births is substantially elevated in women who have had assisted reproduction treatment (ART; approximately 26%) compared to the general population ( approximately 1%), and these offspring are usually included in twin studies. Several studies have attempted to identify possible consequences of undergoing ART on the subsequent offspring. However, most studies have only included singleton births. We first examined whether twins born by ART differed from other twins on measures of childhood psychopathology, putative risk factors and correlates, and secondly tested for differences in the degree of twin similarity for available outcome measures. From a population-based twin sample, 101 families with dizygotic (DZ) twins conceived via ART were identified and compared with 1073 naturally conceived (NC) control DZ twin pairs. Analyses performed were (1) univariate and multivariate comparisons of between-group mean differences; and (2) comparison of twin 1-twin 2 correlations between the groups. The groups differed significantly on demographic factors (parental age, family size and social class) and pregnancy variables (smoking during pregnancy and birthweight) but did not differ on family conflict scores or in the frequency of obstetric complications. Family cohesion was higher in the ART group but this was accounted for by demographic factors. For child psychopathology there was a difference between the groups only for teacher-rated ADHD (Attention Deficit Hyperactivity Disorder). Differences were also found between groups for twin correlations. The differences found between ART and NC twins on group means and twin correlations suggest that researchers should be aware that including ART twins may influence results from twin studies.

  13. Twin's sex and risk of pre-term birth.

    PubMed

    Haghighi, L; Najmi, Z; Barzegar, S H; Barzegar, N

    2013-11-01

    Male sex is a risk factor for pre-term birth (PTB) among singleton pregnancies; however, in twin pregnancies, the effect of sex on PTB is not yet clear. The aim of this study was to evaluate the effect of twin's sex on risk of PTB. During this analytical cross-sectional study, we evaluated the effect of twin's sex, chorionicity and other factors on risk of PTB in 676 pregnant women in a university hospital in Tehran, Iran. Existence of male gender in pregnancy was a risk factor for PTB. Comparing same sex twins together, male-male gender was a risk factor for PTB (OR = 1.67 (1.19-2.34), p = 0.002), early PTB (OR = 1.18 (1.04-1.34), p = 0.01) and very early PTB (OR = 1.06 (1-1.13), p = 0.04). Monoamnion twins were at higher risk for early PTB (OR = 1.44 (1.08-1.92), p = 0.02), and very early PTB (OR = 1.95 (1.1-3.44), p = 0.03) but the risk did not increase in monochorion twins. History of abortion was also shown to be a risk factor (p < 0.05). Maternal age, multiparity, body mass index (BMI) and assisted reproductive techniques (ART) did not reach the significance levels to be considered as risk factors.

  14. Inter-speaker articulatory variability during vowel-consonant-vowel sequences in twins and unrelated speakers.

    PubMed

    Weirich, Melanie; Lancia, Leonardo; Brunner, Jana

    2013-11-01

    The purpose of this study is to examine and compare the amount of inter-speaker variability in the articulation of monozygotic twin pairs (MZ), dizygotic twin pairs (DZ), and pairs of unrelated twins with the goal of examining in greater depth the influence of physiology on articulation. Physiological parameters are assumed to be very similar in MZ twin pairs in contrast to DZ twin pairs or unrelated speakers, and it is hypothesized that the speaker specific shape of articulatory looping trajectories of the tongue is at least partly dependent on biomechanical properties and the speaker's individual physiology. By means of electromagnetic articulography (EMA), inter-speaker variability in the looping trajectories of the tongue back during /VCV/ sequences is analyzed. Results reveal similar looping patterns within MZ twin pairs but in DZ pairs differences in the shape of the loop, the direction of the upward and downward movement, and the amount of horizontal sliding movement at the palate are found.

  15. Yoruba customs and beliefs pertaining to twins.

    PubMed

    Leroy, Fernand; Olaleye-Oruene, Taiwo; Koeppen-Schomerus, Gesina; Bryan, Elizabeth

    2002-04-01

    The Yoruba are an important ethnic group mainly occupying Southwestern Nigeria. Mainly for genetic reasons, this very large tribe happens to present the highest dizygotic twinning rate in the world (4.4 % of all maternities). The high perinatal mortality rate associated with such pregnancies has contributed to the integration of a special twin belief system within the African traditional religion of this tribe. The latter is based on the concept of a supreme deity called Olodumare or Olorun, assisted by a series of secondary gods (Orisha) while Yoruba religion also involves immortality and reincarnation of the soul based on the animistic cult of ancestors. Twins are therefore given special names and believed to detain special preternatural powers. In keeping with their refined artistic tradition, the Yoruba have produced numerous wooden statuettes called Ibejis that represent the souls of deceased newborn twins and are involved in elaborate rituals. Among Yoruba traditional beliefs and lore some twin-related themes are represented which are also found in other parts of the world. Basic features of the original Yoruba beliefs have found their way into the religious traditions of descendants of African slaves imported in the West Indies and in South America.

  16. Genetic and experiential influences on behavior: Twins reunited at seventy-eight years.

    PubMed

    Segal, Nancy L; Cortez, Franchesca A; Zettel-Watson, Laura; Cherry, Barbara J; Mechanic, Mindy; Munson, Jaimee E; Velázquez, Jaime M A; Reed, Brandon

    2015-01-01

    Twins living in different countries offer opportunities to explore associations between observed differences and experiential effects. This report compared the life histories, cognitive abilities, personality traits, psychomotor skills, medical characteristics, job satisfaction, social support and social relations of dizygotic (DZ) female twins reunited at 78, the world's longest separated set. The twins' advanced age also enabled a study of how co-twin differences in aging may be associated with current behavioral and social differences. Consistent with previous studies, these dizygotic reared apart (DZA) twins showed discordance across some, but not all, traits. Their different rearing situations and life histories may explain current differences in their responses to meeting their twin. This case highlights the importance of both genetic and rearing factors on behavior, but does not allow firm conclusions regarding the extent to which these sources explain individual developmental differences. However, such data contribute to the growing number of cross-culturally separated twins, generating novel hypotheses that may be assessed using larger samples.

  17. Clinical outcomes after assisted reproductive technology in twin pregnancies: chorionicity-based comparison

    PubMed Central

    Sun, Luming; Zou, Gang; Wei, Xing; Chen, Yan; Zhang, Jun; Okun, Nanette; Duan, Tao

    2016-01-01

    The chorionicity–based evaluation of the perinatal risk in twin pregnancies after assisted reproductive technology (ART) is lacking. A retrospective review was performed of all twin pregnancies monitored prenatally and delivered at our hospital between 2010 and 2014. Chorionicity was diagnosed by ultrasound examination at first trimester and confirmed by postnatal pathology. Pregnancy and perinatal outcomes were prospectively recorded. Adjusted odds ratios (aOR) with 95% confidence intervals (CI) were calculated in a logistic regression model. A total of 1153 twin pregnancies were analyzed. The occurrence of preterm premature rupture of membranes (PPROM) was 3 times as frequent in monochorionic diamniotic (MCDA) twin pregnancies after ART as in those spontaneous counterparts (aOR 3.0; 95%CI 1.1–3.2). The prevalence of intrahepatic cholestasis of pregnancies (ICP) was significantly higher in dichorionic diamniotic (DCDA) twin pregnancies following ART compared to spontaneous DCDA pregnancies (aOR 3.3; 95%CI 1.3–5.6). Perinatal outcomes did not differ between two conception methods, either in MCDA or DCDA twin pregnancies. Based on differentiation of chorionicity, ART is associated with the increased risk of PPROM in MCDA twin pregnancies and with a higher rate of ICP in DCDA twin gestations. ART does not increase adversity of perinatal outcomes in twin pregnancies. PMID:27243373

  18. Non-random X chromosome inactivation in an affected twin in a monozygotic twin pair discordant for Wiedemann-Beckwith syndrome

    SciTech Connect

    Oestavik, R.E.; Eiklid, K.; Oerstavik, K.H.

    1995-03-27

    Wiedemann-Beckwith syndrome (WBS) is a syndrome including exomphalos, macroglossia, and generalized overgrowth. The locus has been assigned to 11p15, and genomic imprinting may play a part in the expression of one or more genes involved. Most cases are sporadic. An excess of female monozygotic twins discordant for WBS have been reported, and it has been proposed that this excess could be related to the process of X chromosome inactivation. We have therefore studied X chromosome inactivation in 13-year-old monozygotic twin girls who were discordant for WBS. In addition, both twins had Tourette syndrome. The twins were monochorionic and therefore the result of a late twinning process. This has also been the case in previously reported discordant twin pairs with information on placentation. X chromosome inactivation was determined in DNA from peripheral blood cells by PCR analysis at the androgen receptor locus. The affected twin had a completely skewed X inactivation, where the paternal allele was on the active X chromosome in all cells. The unaffected twin had a moderately skewed X inactivation in the same direction, whereas the mother had a random pattern. Further studies are necessary to establish a possible association between the expression of WBS and X chromosome inactivation. 18 refs., 2 figs., 1 tab.

  19. Estimating heritability for cause specific mortality based on twin studies.

    PubMed

    Scheike, Thomas H; Holst, Klaus K; Hjelmborg, Jacob B

    2014-04-01

    There has been considerable interest in studying the magnitude and type of inheritance of specific diseases. This is typically derived from family or twin studies, where the basic idea is to compare the correlation for different pairs that share different amount of genes. We here consider data from the Danish twin registry and discuss how to define heritability for cancer occurrence. The key point is that this should be done taking censoring as well as competing risks due to e.g.  death into account. We describe the dependence between twins on the probability scale and show that various models can be used to achieve sensible estimates of the dependence within monozygotic and dizygotic twin pairs that may vary over time. These dependence measures can subsequently be decomposed into a genetic and environmental component using random effects models. We here present several novel models that in essence describe the association in terms of the concordance probability, i.e., the probability that both twins experience the event, in the competing risks setting. We also discuss how to deal with the left truncation present in the Nordic twin registries, due to sampling only of twin pairs where both twins are alive at the initiation of the registries.

  20. Individual differences in locus of control during the second half of the life span for identical and fraternal twins reared apart and reared together.

    PubMed

    Pedersen, N L; Gatz, M; Plomin, R; Nesselroade, J R; McClearn, G E

    1989-07-01

    The relative influences of genetic and environmental factors for components of locus of control (LOC) were examined in the Swedish Adoption/Twin Study of Aging. The sample consisted of 84 pairs of monozygotic twins separated at an early age and reared apart, 173 pairs of dizygotic twins reared apart, 129 monozygotic pairs reared together, and 168 dizygotic pairs reared together. At the time of data collection, 72% were over 50 years of age. Three LOC components were measured in a mailed questionnaire: sense of personal control or lack of control over the direction of one's own life (Life Direction), beliefs about how responsible people are for misfortunes in their lives (Responsibility), and beliefs concerning the role of luck in determining people's outcomes (Luck). Model-fitting results indicated that genetic influences were of importance for Life Direction and Responsibility, accounting for somewhat over 30% of the variance in each component, while environmental influences explained twin similarity for Luck.

  1. 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 ...

  2. The CODAtwins project: the cohort description of COllaborative project of Development of Anthropometrical measures in Twins to study macro-environmental variation in genetic and environmental effects on anthropometric traits

    PubMed Central

    Silventoinen, Karri; Jelenkovic, Aline; Sund, Reijo; Honda, Chika; Aaltonen, Sari; Yokoyama, Yoshie; Tarnoki, Adam D; Tarnoki, David L; Ning, Feng; Ji, Fuling; Pang, Zengchang; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Burt, S Alexandra; Klump, Kelly L; Medland, Sarah E; Montgomery, Grant W; Kandler, Christian; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Saudino, Kimberly J; Dubois, Lise; Boivin, Michel; Haworth, Claire MA; Plomin, Robert; Öncel, Sevgi Y; Aliev, Fazil; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Craig, Jeffrey M; Saffery, Richard; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Spector, Timothy; Mangino, Massimo; Lachance, Genevieve; Gatz, Margaret; Butler, David A; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Freitas, Duarte L; Maia, José Antonio; Harden, K Paige; Tucker-Drob, Elliot M; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Hong, Changhee; Chong, Youngsook; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth JF; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; He, Mingguang; Ding, Xiaohu; Chang, Billy; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Cutler, Tessa L; Hopper, John L; Aujard, Kelly; Magnusson, Patrik KE; Pedersen, Nancy L; Dahl-Aslan, Anna K; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Baker, Laura A; Tuvblad, Catherine; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Heikkilä, Kauko; Tan, Qihua; Zhang, Dongfeng; Swan, Gary E; Krasnow, Ruth; Jang, Kerry L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Lichtenstein, Paul; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Tynelius, Per; Duncan, Glen E; Buchwald, Dedra; Corley, Robin P; Huibregtse, Brooke M; Nelson, Tracy L; Whitfield, Keith E; Franz, Carol E; Kremen, William S; Lyons, Michael J; Ooki, Syuichi; Brandt, Ingunn; Nilsen, Thomas Sevenius; Inui, Fujio; Watanabe, Mikio; Bartels, Meike; van Beijsterveldt, Toos CEM; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; Rebato, Esther; Martin, Nicholas G; Iwatani, Yoshinori; Hayakawa, Kazuo; Rasmussen, Finn; Sung, Joohon; Harris, Jennifer R; Willemsen, Gonneke; Busjahn, Andreas; Goldberg, Jack H; Boomsma, Dorret I; Hur, Yoon-Mi; Sørensen, Thorkild IA; Kaprio, Jaakko

    2015-01-01

    For over one hundred years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically 1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and 2) to study the effects of birth related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects including both monozygotic and dizygotic twins using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes. PMID:26014041

  3. Familial risk and ADHD-specific neural activity revealed by case-control, discordant twin pair design.

    PubMed

    Godinez, Detre A; Willcutt, Erik G; Burgess, Gregory C; Depue, Brendan E; Andrews-Hanna, Jessica R; Banich, Marie T

    2015-09-30

    Individuals with ADHD, as well as their family members who do not meet clinical criteria, have shown deficits in executive function. However, it remains unclear whether underlying neural alterations are familial or ADHD-specific. To investigate this issue, neural activation underlying executive function was assessed using functional magnetic resonance imaging during performance of a Stroop task in three groups of individuals: 20 young adults who were diagnosed with ADHD in childhood, their 20 dizygotic co-twins without ADHD in childhood, and 20 unrelated controls selected from dizygotic twin pairs in which neither twin had ADHD in childhood (total n=60). Implicating the frontoparietal network as a location of effects specific to ADHD, activation in the superior frontal (Brodmann's Area - BA 6) and parietal regions (BA 40) was significantly reduced in twins with childhood ADHD compared to both their control co-twins and unrelated control twins. Consistent with familial influences, activity in the anterior cingulate and insula was significantly reduced in both the twins with ADHD and their co-twins compared to the unrelated controls. These results show that both ADHD-specific and familial influences related to an ADHD diagnosis impact neural systems underlying executive function.

  4. In utero drugs of abuse exposure testing for newborn twins.

    PubMed

    Wang, Ping; Molina, Claudia P; Maldonado, Joyce E; Bernard, David W

    2010-03-01

    This report describes testing of a case of in utero drugs of abuse exposure in which discordant results were seen between urine and meconium, and between twin meconium samples. The discordance between urine and meconium could be explained by the differences in detection window, threshold concentration and screening technology, and the discordance between dizygotic twin meconium samples could be explained by the differences in drug diffusion and placental and fetal biotransformation of drugs. The meconium sample of one twin screened negative for benzodiazepines was reported positive in the confirmation assay with higher sensitivity and a lower cut-off concentration. Negative screening results of drugs of abuse should be interpreted with caution, taking into account matrix type, reactivity of drugs in the assay and cut-off concentration. If screening results are inconsistent with each other or with the clinical scenario, confirmation testing using more sensitive and specific methods with lower cut-offs is warranted.

  5. Genetic and experiential influences on behavior: Twins reunited at seventy-eight years

    PubMed Central

    Segal, Nancy L.; Cortez, Franchesca A.; Zettel-Watson, Laura; Cherry, Barbara J.; Mechanic, Mindy; Munson, Jaimee E.; Velázquez, Jaime M.A.; Reed, Brandon

    2015-01-01

    Twins living in different countries offer opportunities to explore associations between observed differences and experiential effects. This report compared the life histories, cognitive abilities, personality traits, psychomotor skills, medical characteristics, job satisfaction, social support and social relations of dizygotic (DZ) female twins reunited at 78, the world's longest separated set. The twins’ advanced age also enabled a study of how co-twin differences in aging may be associated with current behavioral and social differences. Consistent with previous studies, these dizygotic reared apart (DZA) twins showed discordance across some, but not all, traits. Their different rearing situations and life histories may explain current differences in their responses to meeting their twin. This case highlights the importance of both genetic and rearing factors on behavior, but does not allow firm conclusions regarding the extent to which these sources explain individual developmental differences. However, such data contribute to the growing number of cross-culturally separated twins, generating novel hypotheses that may be assessed using larger samples. PMID:26366029

  6. Isolated Single Umbilical Artery in Twin Pregnancies and its Adverse Pregnancy Outcomes - A Case Report and Review of Literature

    PubMed Central

    Raiz, Iqbal

    2015-01-01

    Single umbilical artery is the most common congenital abnormality of the umbilical cord and is seen in 4-11% of twin pregnancies. It is usually associated with intrauterine growth retardation, preterm labour, small-for-dates and other structural anomalies. There is no significant difference in the incidence between monochorionic and dichorionic twins. The left artery is usually absent more commonly than the right. The female co-twin was predominantly more affected than their male counterparts. Single umbilical artery is found twice more common in white women than in Afro-Asians and Americans. The hemodynamic disturbances occur early in the embryonic development, influence greatly in the development of single umbilical artery. Genetic and environmental factors also play a major role in the development of this anomaly. The pregnancies with single umbilical artery were classified as high risk group, because the overall perinatal mortality rate was estimated to be as high as 20%. There is a significant increase in the occurrence of single umbilical artery in pregnancies due to artificial reproductive technologies, as well as in spontaneous miscarriages. Prenatal ultrasonography is the principal diagnostic technique employed to identify single umbilical artery during 3rd trimester of pregnancy. The present case, reports the presence of a single umbilical artery in a monozygotic, monochorionic twin pregnancy, which is acardiac-acephalic fetus, small for dates, female sex, associated with other major structural anomalies, and was still born. Authors analyse its incidence, clinical presentations and pregnancy outcome and also review the pertinent literature. PMID:25737967

  7. Healthy co-twins of patients with affective disorders show reduced risk-related activation of the insula during a monetary gambling task

    PubMed Central

    Macoveanu, Julian; Miskowiak, Kamilla; Kessing, Lars Vedel; Vinberg, Maj; Siebner, Hartwig Roman

    2016-01-01

    Background Healthy first-degree relatives of patients with affective disorders are at increased risk for affective disorders and express discrete structural and functional abnormalities in the brain reward system. However, value-based decision making is not well understood in these at-risk individuals. Methods We investigated healthy monozygotic and dizygotic twins with or without a co-twin history of affective disorders (high-risk and low-risk groups, respectively) using functional MRI during a gambling task. We assessed group differences in activity related to gambling risk over the entire brain. Results We included 30 monozygotic and 37 dizygotic twins in our analysis. Neural activity in the anterior insula and ventral striatum increased linearly with the amount of gambling risk in the entire cohort. Individual neuroticism scores were positively correlated with the neural response in the ventral striatum to increasing gambling risk and negatively correlated with individual risk-taking behaviour. Compared with low-risk twins, the high-risk twins showed a bilateral reduction of risk-related activity in the middle insula extending into the temporal cortex with increasing gambling risk. Post hoc analyses revealed that this effect was strongest in dizygotic twins. Limitations The relatively old average age of the mono- and dizygotic twin cohort (49.2 yr) may indicate an increased resilience to affective disorders. The size of the monozygotic high-risk group was relatively small (n = 13). Conclusion The reduced processing of risk magnitude in the middle insula may indicate a deficient integration of exteroceptive information related to risk-related cues with interoceptive states in individuals at familial risk for affective disorders. Impaired risk processing might contribute to increased vulnerability to affective disorders. PMID:26395812

  8. Conjoined Twins

    MedlinePlus

    ... each other. Conjoined twins develop when an early embryo only partially separates to form two individuals. Although two fetuses will develop from this embryo, they will remain physically connected — most often at ...

  9. Twin's Birth-Order Differences in Height and Body Mass Index From Birth to Old Age: A Pooled Study of 26 Twin Cohorts Participating in the CODATwins Project.

    PubMed

    Yokoyama, Yoshie; Jelenkovic, Aline; Sund, Reijo; Sung, Joohon; Hopper, John L; Ooki, Syuichi; Heikkilä, Kauko; Aaltonen, Sari; Tarnoki, Adam D; Tarnoki, David L; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos C E M; Saudino, Kimberly J; Cutler, Tessa L; Nelson, Tracy L; Whitfield, Keith E; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; He, Mingguang; Ding, Xiaohu; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Jeong, Hoe-Uk; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Burt, S Alexandra; Klump, Kelly L; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Harris, Jennifer R; Brandt, Ingunn; Nilsen, Thomas Sevenius; Craig, Jeffrey M; Saffery, Richard; Ji, Fuling; Ning, Feng; Pang, Zengchang; Dubois, Lise; Boivin, Michel; Brendgen, Mara; Dionne, Ginette; Vitaro, Frank; Martin, Nicholas G; Medland, Sarah E; Montgomery, Grant W; Magnusson, Patrik K E; Pedersen, Nancy L; Aslan, Anna K Dahl; Tynelius, Per; Haworth, Claire M A; Plomin, Robert; Rebato, Esther; Rose, Richard J; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Sørensen, Thorkild I A; Boomsma, Dorret I; Kaprio, Jaakko; Silventoinen, Karri

    2016-04-01

    We analyzed birth order differences in means and variances of height and body mass index (BMI) in monozygotic (MZ) and dizygotic (DZ) twins from infancy to old age. The data were derived from the international CODATwins database. The total number of height and BMI measures from 0.5 to 79.5 years of age was 397,466. As expected, first-born twins had greater birth weight than second-born twins. With respect to height, first-born twins were slightly taller than second-born twins in childhood. After adjusting the results for birth weight, the birth order differences decreased and were no longer statistically significant. First-born twins had greater BMI than the second-born twins over childhood and adolescence. After adjusting the results for birth weight, birth order was still associated with BMI until 12 years of age. No interaction effect between birth order and zygosity was found. Only limited evidence was found that birth order influenced variances of height or BMI. The results were similar among boys and girls and also in MZ and DZ twins. Overall, the differences in height and BMI between first- and second-born twins were modest even in early childhood, while adjustment for birth weight reduced the birth order differences but did not remove them for BMI.

  10. Trends in occurrence of twin births in Japan.

    PubMed

    Kurosawa, Kenji; Masuno, Mitsuo; Kuroki, Yoshikazu

    2012-01-01

    The rise in the rate of multiple births since the 1980s is due to the effect of advanced maternal age and increased use of assisted reproductive technology (ART). To determine the trends of prevalence in twin births, we studied the data of a population-based birth defects monitoring system during 26 years in Kanagawa Prefecture, Japan. A total of 15,380 twins from 7,690 deliveries were ascertained from 990,978 births in the Kanagawa Birth Defects Monitoring Program (KAMP) during 1981-2008. From the start of KAMP in 1981, the incidence of twin births had been consistently increasing from 57.0 to 98.6 per 10,000 deliveries until 2003, but after this time, the incidence declined to 78.5 in 2007. While the rate of monozygotic twins has been stable (∼40 per 10,000 deliveries) after 1990, that of dizygotic twins increased from 25.3 to 57.3 per 10,000 deliveries until 2002, and recovered to 40.1 in 2007. These results showed the most recent tendency of twin births and indicated that the single embryo transfer method can provide protection and reduction of perinatal risk caused by multiple births.

  11. The Genetics of Sexuality and Aggression (GSA) twin samples in Finland.

    PubMed

    Johansson, Ada; Jern, Patrick; Santtila, Pekka; von der Pahlen, Bettina; Eriksson, Elias; Westberg, Lars; Nyman, Henrik; Pensar, Johan; Corander, Jukka; Sandnabba, N Kenneth

    2013-02-01

    The Genetics of Sexuality and Aggression (GSA) project was launched at the Abo Akademi University in Turku, Finland in 2005 and has so far undertaken two major population-based data collections involving twins and siblings of twins. To date, it consists of about 14,000 individuals (including 1,147 informative monozygotic twin pairs, 1,042 informative same-sex dizygotic twin pairs, 741 informative opposite-sex dizygotic twin pairs). Participants have been recruited through the Central Population Registry of Finland and were 18-49 years of age at the time of the data collections. Saliva samples for DNA genotyping (n = 4,278) and testosterone analyses (n = 1,168) were collected in 2006. The primary focus of the data collections has been on sexuality (both sexual functioning and sexual behavior) and aggressive behavior. This paper provides an overview of the data collections as well as an outline of the phenotypes and biological data assembled within the project. A detailed overview of publications can be found at the project's Web site: http://www.cebg.fi/.

  12. A twin study of posttraumatic stress disorder symptoms and chronic widespread pain.

    PubMed

    Arguelles, Lester M; Afari, Niloofar; Buchwald, Dedra S; Clauw, Daniel J; Furner, Sylvia; Goldberg, Jack

    2006-09-01

    Previous studies of the association between posttraumatic stress disorder (PTSD) and chronic widespread pain (CWP) or fibromyalgia have not examined the role of familial or genetic factors. The goals of this study were to determine if symptoms of PTSD are related to CWP in a genetically informative community-based sample of twin pairs, and if so, to ascertain if the association is due to familial or genetic factors. Data were obtained from the University of Washington Twin Registry, which contains 1042 monozygotic and 828 dizygotic twin pairs. To assess the symptoms of PTSD, we used questions from the Impact of Events Scale (IES). IES scores were partitioned into terciles. CWP was defined as pain located in 3 body regions lasting at least 1 week during the past 3 months. Random-effects regression models, adjusted for demographic features and depression, examined the relationship between IES and CWP. IES scores were strongly associated with CWP (P<0.0001). Compared to those in the lowest IES tercile, twins in the highest tercile were 3.5 times more likely to report CWP. Although IES scores were associated with CWP more strongly among dizygotic than among monozygotic twins, this difference was not significant. Our findings suggest that PTSD symptoms, as measured by IES, are strongly linked to CWP, but this association is not explained by a common familial or genetic vulnerability to both conditions. Future research is needed to understand the temporal association of PTSD and CWP, as well as the physiological underpinnings of this relationship.

  13. Increased risk of congenital heart disease in twins in the North of England between 1998 and 2010

    PubMed Central

    Best, K E; Rankin, J

    2015-01-01

    Objective To examine the relative risk (RR) of congenital heart disease (CHD) in twins compared with singletons, according to chorionicity. Methods Twins and singletons with CHD notified to the Northern Congenital Abnormality Survey between 1998 and 2010 were included in this population-based study. Information on chorionicity was obtained from the Northern Survey of Twins and Multiple Pregnancy. Prevalence was calculated as the number of cases occurring in live births, late miscarriages (20–23 weeks), stillbirths (≥24 weeks) and terminations of pregnancy for fetal anomaly, per 10 000 total births. The risk of CHD in twins compared with singletons was estimated using Poisson regression. Results There were 399 414 singleton births of which 2984 (0.7%) had CHD. Among 11 871 twin births, 154 (1.3%) had CHD; one twin was affected by CHD in 2.5% of twin pregnancies. Of 8605 dichorionic (DC) births and 2317 monochorionic (MC) births, 96 (1.1%) and 47 (2.0%) were associated with CHD. Compared with singletons, twins were at significantly increased risk of CHD (RR=1.73, 95% CI 1.48 to 2.04; p<0.001). MC twins were at 82% significantly increased risk of CHD compared with DC twins (RR=1.82, 95% CI 1.29 to 2.57; p<0.001). The RR of severe and mild CHD was particularly high in MC twins compared with singletons (292% increased risk, RR=3.92, 95% CI 1.25 to 12.30, p=0.02 and 207% increased risk, RR=3.07, 95% CI 2.20 to 4.28; p<0.001). Conclusions Compared with singletons, twins were at increased risk of CHD, the risk being substantially higher among MC twins. This information is important for health professionals when counselling women with twin pregnancies. PMID:26412859

  14. Parent ratings of EAS temperaments in twins, full siblings, half siblings, and step siblings.

    PubMed

    Saudino, K J; McGuire, S; Reiss, D; Hetherington, E M; Plomin, R

    1995-04-01

    A twin/family design was used to explore genetic contributions to personality; to evaluate whether twins and nontwins yield different genetic results; and to test for the presence of contrast effects, the tendency of a rater to contrast one sibling with the other, thereby magnifying existing behavioral differences. The sample consisted of 708 adolescent same-sex sibling pairs from 10 to 18 years of age. Pairs included identical (monozygotic; MZ) and fraternal (dizygotic; DZ) twins, and full siblings in nondivorced families; and full, half, and unrelated siblings in stepfamilies. Mothers and fathers rated the temperament of their children on the EAS Temperament Survey (A. H. Buss & R. Plomin, 1984). Model-fitting analyses revealed significant genetic influences on each of the four EAS dimensions; however, for some dimensions, heritability estimates were significantly greater for twins than for nontwins. Overall, the data were best described by a sibling interaction model, which indicated significant contrast effects.

  15. Evidence for No Significant Impact of Müllerian Anomalies on Reproductive Outcomes of Twin Pregnancy in Korean Women.

    PubMed

    Shim, Sohyun; Hur, Yoon-Mi; Kim, Da Hee; Seong, Seok Ju; Kim, Mi-La; Shin, Joong Sik

    2016-04-01

    The present article aimed to evaluate the impact of congenital Müllerian anomalies (MA) on twin pregnancy after 24 gestational weeks in Korean women. All records of twin pregnancies in a large maternity hospital in Korea between January 2005 and July 2013 were analyzed. Patients with monochorionic monoamniotic (MCMA) twins, non-Korean patients, patients with twins delivered prior to 24 gestational weeks, and patients with miscarriage of one fetus or intrauterine fetal death (IUFD) before 24 gestational weeks were excluded from data analysis. In total, 1,422 women with twin pregnancy were eligible for data analysis, including 17 (1.2%) who had a known congenital MA (septate uterus, bicornuate uterus, arcuate uterus, and unicornuate uterus). Except for the mode of conception, baseline demographics were similar between women with MA and those without MA. No significant differences were found in pregnancy outcomes of gestational age at delivery (p = .86), birth weight of smaller and larger twins (p = .54 and p = .65), and number of twins with birth weight <5th percentile for gestational age (p = .43).The rates of obstetrical complications such as pre-eclampsia, gestational diabetes mellitus (GDM), placenta previa, cerclage, IUFD, and postpartum hemorrhage were not significantly different between the two groups either. We concluded that the presence of congenital MA may not increase obstetrical risks in outcomes of pregnancy of twins delivered after 24 gestational weeks.

  16. Masculinity and femininity in twin children: genetic and environmental factors.

    PubMed

    Mitchell, J E; Baker, L A; Jacklin, C N

    1989-12-01

    Genetic and environmental origins of individual differences in masculine and feminine personality attributes were investigated in a sample of 38 monozygotic and 32 dizygotic twin pairs (total N = 140) during pre- and early adolescence. Self-report measures of both masculine and feminine characteristics were obtained for each child using 2 standardized instruments: the Children's Personality Attributes Questionnaire (CPAQ) and the Adolescent Self-Perception Inventory (ASPI). Multivariate biometrical analyses revealed significant genetic influences in all measures, accounting for 20%-48% of the observed variation in each. Environmental influences, which explained the remaining 52%-80% of variance in masculinity and femininity, were apparently specific to each individual and not shared by members of the same twin pair. The results underscore the importance of considering both genetic and environmental factors in gender-role development, particularly in studies of family resemblance.

  17. Cerebral asymmetry in twins: predictions of the right shift theory.

    PubMed

    Annett, Marian

    2003-01-01

    A study of the heritability of lobar brain volumes in twins has introduced a new approach to questions about the genetics of cerebral asymmetry. In addition to the classic comparison between monozygotic (MZ) and dizygotic (DZ) twins, a contrast was made between pairs of two right-handers (RR pairs) and pairs including one or more non-right-hander (non-RR pairs), in the light of the right shift (RS) theory of handedness. This paper explains the predictions of the RS model for pair concordance for genotype, cerebral asymmetry and handedness in healthy MZ and DZ twins. It shows how predictions for cerebral asymmetry vary between RR and non-RR pairs over a range of incidences of left-handedness. Although MZ twins are always concordant for genotype and DZ twins may be discordant, differences for handedness and cerebral asymmetry are expected to be small, consistent with the scarcity of significant effects in the literature. Marked differences between RR and non-RR pairs are predicted at all levels of incidence, the differences slightly larger in MZ than DZ pairs.

  18. [Neurodevelopmental Outcomes of Very Preterm or Very Low Birth Weigth Infants: Comparison of Monochorionic and Dichorionic Twins with Singletons].

    PubMed

    Taborda, Adelaide; Oliveira, Guiomar

    2016-11-01

    Introdução: Estudos evidenciaram maior taxa de alterações do neurodesenvolvimento nos gémeos em relação aos recém-nascidos de gestação unifetal. O objetivo deste trabalho foi comparar alterações do neurodesenvolvimento em gémeos (monocoriónicos e bicoriónicos) grandes prematuros ou de muito baixo peso ao nascer, com recém-nascidos de gestação unifetal. Material e Métodos: Estudo retrospetivo de uma coorte de recém-nascidos com idade gestacional inferior a 32 semanas ou peso de nascimento inferior a 1500 g, internados na Unidade de Cuidados Intensivos Neonatais, numa maternidade de apoio perinatal diferenciado da Região Centro de Portugal, no período de 2006 a 2010. A avaliação do neurodesenvolvimento foi realizada aos 24 meses, com a escala de Growing Skills II. No diagnóstico de paralisia cerebral usou-se a classificação internacional de Surveillance of Cerebral Palsy in Europe. Foram comparados recém-nascidos de gestação unifetal com recém-nascidos de gravidez múltipla e com os subgrupos: monocoriónicos e bicoriónicos. Análise estatística pelo SPSS versão 20.0. Foi aplicado um modelo de regressão logística. Resultados: Foram avaliados 194 recém-nascidos do grupo gestação unifetal e 89 gémeos - 50 bicoriónicos e 39 monocoriónicos. Os gémeos monocoriónicos apresentaram maior risco, em relação ao grupo de gestação unifetal, de alterações moderadas a graves do neurodesenvolvimento global (OR ajustado 3,6) e nas subáreas: locomoção (OR ajustado 12,2) linguagem (OR ajustado 6,5) e autonomia (OR ajustado 7,2). A paralisia cerebral foi diagnosticada em 15,4% dos gémeos monocoriónicos e 4,1% de gestação unifetal(OR ajustado 4,2). Discussão: Este trabalho evidenciou taxa superior de alterações moderadas a graves do neurodesenvolvimento, incluindo a paralisia cerebral nos gémeos monocoriónicos em relação ao grupo de gestação unifetal. A análise por grupos estratificados em relação à idade gestacional e a comparação de monocoriónicos com bicoriónicos alertou para o papel da corionicidade na base destas sequelas. Conclusão: Podemos concluir que os gémeos monocoriónicos apresentaram, na população estudada, um risco significativo de sequelasmoderadas a graves do neurodesenvolvimento.

  19. Examining Associations Among ADHD, Homework Behavior, and Reading Comprehension: A Twin Study.

    PubMed

    Little, Callie W; Hart, Sara A; Schatschneider, Christopher; Taylor, Jeanette

    2016-07-01

    Previous literature has indicated an important association between reading comprehension and both attention-deficit/hyperactivity disorder (ADHD) and homework habits. This investigation sought to extend previous knowledge by providing information about how ADHD and homework behavior (i.e., completing homework regularly) may jointly influence reading comprehension. Using a genetically sensitive design, this study examined the genetic and environmental influences on and between ADHD, homework behavior and reading comprehension. Participants for this study included 691 twin pairs (351 monozygotic, 340 same-sex dizygotic) from the Florida Twin Project on Behavior and Environment (FTP-BE) and 2647 twin pairs (865 monozygotic, 1782 dizygotic) from the larger Florida Twin Project on Reading (FTP-R) in Grades 3 through 7. Three separate models, each representing a different definition of ADHD (full ADHD, inattention only, and hyperactivity/impulsivity only), showed similar patterns of results; therefore, results of the full ADHD model are discussed. Overlapping genetic influences were found between ADHD, homework behavior, and reading comprehension, but no shared environmental influences among all three. However, shared environmental influences overlapped between homework behavior and reading comprehension. Although the sources of this environmental overlap are unknown, these results have implications for improving homework practices and their subsequent influence on literacy skills through homework environments.

  20. The contribution of twins to the study of cognitive ageing and dementia: the Older Australian Twins Study.

    PubMed

    Sachdev, Perminder S; Lee, Teresa; Wen, Wei; Ames, David; Batouli, Amir H; Bowden, Jocelyn; Brodaty, Henry; Chong, Elizabeth; Crawford, John; Kang, Kristan; Mather, Karen; Lammel, Andrea; Slavin, Melissa J; Thalamuthu, Anbupalam; Trollor, Julian; Wright, Margie J

    2013-12-01

    The Older Australian Twins Study (OATS) is a major longitudinal study of twins, aged ≥ 65 years, to investigate genetic and environmental factors and their interactions in healthy brain ageing and neurocognitive disorders. The study collects psychiatric, neuropsychological, cardiovascular, metabolic, biochemical, neuroimaging, genomic and proteomic data, with two-yearly assessments, and is currently in its third wave. The initial cohort comprises 623 individuals (161 monozygotic and 124 dizygotic twin pairs; 1 MZ triplets; 27 single twins and 23 non-twin siblings), of whom 426 have had wave 2 assessment. A number of salient findings have emerged thus far which assist in the understanding of genetic contributions to cognitive functions such as processing speed, executive ability and episodic memory, and which support the brain reserve hypothesis. The heritability of brain structures, both cortical and subcortical, brain spectroscopic metabolites and markers of small vessel disease, such as lacunar infarction and white matter hyperintensities, have been examined and can inform future genetic investigations. Work on amyloid imaging and functional magnetic resonance imaging is proceeding and epigenetic studies are progressing. This internationally important study has the potential to inform research into cognitive ageing in the future, and offers an excellent resource for collaborative work.

  1. Twin studies as a model for exploring the aetiology of autoimmune thyroid disease.

    PubMed

    Brix, Thomas Heiberg; Hegedüs, Laszlo

    2012-04-01

    Twins are an important resource for evaluating the relative contribution of genetic and environmental factors in determining a phenotype. During the last decades, a number of twin studies have investigated the aetiology of several phenotypes related to thyroid autoimmunity. Taken together, these studies have provided valid and unbiased information regarding the influence of genetic and environmental factors in the aetiology of autoimmune thyroid disease (AITD). The comparison of concordance rates between monozygotic (MZ) and dizygotic twins provides irrefutable evidence of a genetic component, and biometric twin modelling shows that approximately 75% of the total phenotypic variance in AITD is because of genetic effects. On the other hand, the lack of complete concordance in MZ twin pairs is proof of environmental and/or epigenetic factors also playing an important role. The impact of environmental triggers such as cigarette smoking, birth characteristics, infection with Yersinia enterocolitica, microchimerism and degree of X chromosome inactivation (XCI) has been evaluated by investigating AITD discordant twin pairs. These studies indicate that smoking, Y. enterocolitica infection and skewed XCI may be causally associated with clinically overt AITD, but not with the presence of thyroid autoantibodies in euthyroid subjects. Microchimerism, but not birth weight, might play a role in AITD. Twin studies offer several features that uniquely enhance our ability to localize genes and understand their function. Future twin studies should incorporate information on genetic, epigenetic and environmental variation thereby enhancing our ability to quantify the precise effect of specific risk factors.

  2. Newborn infant characteristics and risk of future rheumatoid arthritis: a twin-control study.

    PubMed

    Svendsen, Anders J; Kyvik, Kirsten O; Houen, Gunnar; Nielsen, Christian; Holst, René; Skytthe, Axel; Junker, Peter

    2014-04-01

    Low birth weight has been proposed as a risk factor for rheumatoid arthritis (RA). The twin-control study design provides an opportunity to investigate the significance of potential prenatal determinants for adult morbidity by accounting for maternal characteristics and early environmental and genetic factors. We investigated the association between birth weight and RA in a sample of 42 twin pairs discordant for rheumatoid arthritis in which valid information on birth weight, birth length, and order was available from midwife records. Difference plot and conditional logistic regression were used to investigate the relationship between RA and birth weight or birth order adjusting for birth length and sex. The intra-pairwise birth weight differences, i.e., RA twin minus co-twin, ranged from -750 to 1,100 g, mean 78 g (95 % CI -13 to 70), 146 g (95 % CI (-36 to 329) in monozygotic, 32 g (95 % CI -90 to 154) in dizygotic, same sex and 69 g (95 % CI -122 to 260) in dizygotic, opposite sex twin pairs. The odds ratio for birth weight as risk factor for RA was 1.00 (95 % CI 0.997-1.003) when adjusting for birth length, birth order, and sex, irrespective of ACPA status. The odds ratio for developing RA as first born twin was 2.33 (95 % CI 0.97-5.60) when adjusting for birth length, birth weight, and sex, irrespective of ACPA status. In this twin-control study, birth weight was not associated with the development of RA in adult life. Being born first may predispose to RA.

  3. Genetics and the environment affect the relationship between depression and low back pain: a co-twin control study of Spanish twins.

    PubMed

    Pinheiro, Marina B; Ferreira, Manuela L; Refshauge, Kathryn; Colodro-Conde, Lucía; Carrillo, Eduvigis; Hopper, John L; Ordoñana, Juan R; Ferreira, Paulo H

    2015-03-01

    Although the co-occurrence of low back pain (LBP) and depression is common, the nature of this association remains unclear. We aimed to investigate whether symptoms of depression are associated with LBP after adjusting for various confounders, including genetics. We used cross-sectional data from 2148 twins from the Murcia Twin Registry, Spain. All twins answered questions about lifetime prevalence of LBP (outcome variable) and symptoms of depression, collected through two instruments, deriving 3 measures: (1) self-report feelings of depression and anxiety; (2) state depression, and (3) trait depression. First, associations were investigated using logistic regression analysis of the total sample. We performed subsequent matched within-pair twin case-control analyses with all complete twin pairs discordant for LBP regardless of zygosity, and separately for dizygotic and monozygotic pairs. This sequential analysis allows for more precise estimates of the relationship between variables, as in each step, the impact of early shared environment and genetics is further considered. Symptoms of depression and anxiety were associated with higher prevalence of LBP in the total sample analysis (odds ratio [OR], 1.64; 95% confidence interval [CI], 1.31-2.05), and this relationship was stronger in the subsequent case-control analysis (OR, 1.74; 95% CI, 1.13-2.69) and dizygotic case-control analysis (OR, 2.39; 95% CI, 1.39-4.08) but disappeared when the analysis was conducted for monozygotic twins (OR, 0.92; 95% CI, 0.42-2.05). A similar pattern was found for state and trait depression. The depression-LBP relationship disappears when high levels of control for confounding factors are applied and seems to be driven by genetic or environmental factors that influence both conditions.

  4. Zygosity differences in height and body mass index of twins from infancy to old age: A study of the CODATwins project

    PubMed Central

    Jelenkovic, Aline; Yokoyama, Yoshie; Sund, Reijo; Honda, Chika; Bogl, Leonie H; Aaltonen, Sari; Ji, Fuling; Ning, Feng; Pang, Zengchang; Ordoñana, Juan R; Sánchez-Romera, Juan F; Colodro-Conde, Lucia; Burt, S Alexandra; Klump, Kelly L; Medland, Sarah E; Montgomery, Grant W; Kandler, Christian; McAdams, Tom A; Eley, Thalia C; Gregory, Alice M; Saudino, Kimberly J; Dubois, Lise; Boivin, Michel; Tarnoki, Adam D; Tarnoki, David L; Haworth, Claire MA; Plomin, Robert; Öncel, Sevgi Y; Aliev, Fazil; Stazi, Maria A; Fagnani, Corrado; D'Ippolito, Cristina; Craig, Jeffrey M; Saffery, Richard; Siribaddana, Sisira H; Hotopf, Matthew; Sumathipala, Athula; Rijsdijk, Fruhling; Spector, Timothy; Mangino, Massimo; Lachance, Genevieve; Gatz, Margaret; Butler, David A; Bayasgalan, Gombojav; Narandalai, Danshiitsoodol; Freitas, Duarte L; Maia, José Antonio; Harden, K Paige; Tucker-Drob, Elliot M; Kim, Bia; Chong, Youngsook; Hong, Changhee; Shin, Hyun Jung; Christensen, Kaare; Skytthe, Axel; Kyvik, Kirsten O; Derom, Catherine A; Vlietinck, Robert F; Loos, Ruth JF; Cozen, Wendy; Hwang, Amie E; Mack, Thomas M; He, Mingguang; Ding, Xiaohu; Chang, Billy; Silberg, Judy L; Eaves, Lindon J; Maes, Hermine H; Cutler, Tessa L; Hopper, John L; Aujard, Kelly; Magnusson, Patrik KE; Pedersen, Nancy L; Aslan, Anna K Dahl; Song, Yun-Mi; Yang, Sarah; Lee, Kayoung; Baker, Laura A; Tuvblad, Catherine; Bjerregaard-Andersen, Morten; Beck-Nielsen, Henning; Sodemann, Morten; Heikkilä, Kauko; Tan, Qihua; Zhang, Dongfeng; Swan, Gary E; Krasnow, Ruth; Jang, Kerry L; Knafo-Noam, Ariel; Mankuta, David; Abramson, Lior; Lichtenstein, Paul; Krueger, Robert F; McGue, Matt; Pahlen, Shandell; Tynelius, Per; Duncan, Glen E; Buchwald, Dedra; Corley, Robin P; Huibregtse, Brooke M; Nelson, Tracy L; Whitfield, Keith E; Franz, Carol E; Kremen, William S; Lyons, Michael J; Ooki, Syuichi; Brandt, Ingunn; Nilsen, Thomas Sevenius; Inui, Fujio; Watanabe, Mikio; Bartels, Meike; van Beijsterveldt, Toos CEM; Wardle, Jane; Llewellyn, Clare H; Fisher, Abigail; Rebato, Esther; Martin, Nicholas G; Iwatani, Yoshinori; Hayakawa, Kazuo; Sung, Joohon; Harris, Jennifer R; Willemsen, Gonneke; Busjahn, Andreas; Goldberg, Jack H; Rasmussen, Finn; Hur, Yoon-Mi; Boomsma, Dorret I; Sørensen, Thorkild IA; Kaprio, Jaakko; Silventoinen, Karri

    2015-01-01

    A trend towards greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in means and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the CODATwins project and included 842,951 height and BMI measurements from age 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Likewise, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast the variance of BMI was significantly higher in DZ than in MZ twins particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes. PMID:26337138

  5. Heritability of Hepatic Fibrosis and Steatosis Based on a Prospective Twin Study

    PubMed Central

    Loomba, Rohit; Schork, Nicholas; Chen, Chi-Hua; Bettencourt, Ricki; Bhatt, Ana; Ang, Brandon; Nguyen, Phirum; Hernandez, Carolyn; Richards, Lisa; Salotti, Joanie; Lin, Steven; Seki, Ekihiro; Nelson, Karen E; Sirlin, Claude B; Brenner, David

    2015-01-01

    Background & Aims Little is known about the heritability of hepatic fibrosis, and the heritability of hepatic steatosis has not been systematically assessed in adults. We investigated the heritability of hepatic fibrosis and steatosis in a community-dwelling twin cohort. Methods We performed a cross-sectional analysis of a cohort of well-characterized twins residing in Southern California including 60 pairs of twins (42 monozygotic and 18 dizygotic; average age, 45.7±22.1 years; average body mass index, 26.4±5.7 kg/m2). We collected data on medical history, physical examinations, fasting laboratory test results, and liver health; all participants underwent an advanced magnetic resonance imaging (MRI) examination of the liver from January 2012 through January 2015. Hepatic steatosis was quantified non-invasively by MRI and determined based on the proton-density fat fraction (MRI-PDFF); liver fibrosis was measured based on stiffness measured by magnetic resonance elastography. Results Twenty-six of the 120 subjects (21.7%) had non-alcoholic fatty liver disease (defined as MRI-PDFF ≥ 5% after exclusion of other causes of hepatic steatosis). The presence of hepatic steatosis correlated between monozygotic twins (r2=0.70, P<.0001) but not between di-zygotic twins (r2=0.36, P=0.2). The level of liver fibrosis also correlated between monozygotic twins (r2=0.48, P<.002) but not between dizygotic twins (r2=.12, P=.7). In multivariable models adjusted for age, sex, and ethnicity, the heritability of hepatic steatosis (based on MRI-PDFF) was 0.52 (95% confidence interval, 0.31–0.73; P<1.1x10−11) and the heritability of hepatic fibrosis (based on liver stiffness) was 0.5 (95% confidence interval, 0.28–0.72; P<6.1 x 10−11). Conclusions A study of twins provides evidence that hepatic steatosis and hepatic fibrosis are heritable traits. PMID:26299412

  6. N-Terminal pro-brain natriuretic peptide levels in dichorionic diamniotic twins with selective intrauterine growth restriction.

    PubMed

    Fujioka, Kazumichi; Mizobuchi, Masami; Sakai, Hitomi; Iwatani, Sota; Wada, Keiko; Yoshimoto, Seiji; Nakao, Hideto

    2014-03-04

    Monochorionic diamniotic (MD) twins with selective intrauterine growth restriction (sIUGR) have known associations with cardiac complications. However, the cardiac load of dichorionic diamniotic (DD) twins with sIUGR (DD-sIUGR) remains unclear. N-terminal pro-brain natriuretic peptide (NT-pro BNP) is a convenient marker of cardiac dysfunction in neonates, and is elevated in MD twins with sIUGR (MD-sIUGR). However, there are no reports assessing serum NT-pro BNP levels in DD-sIUGR. Here, we aimed to clarify serum NT-pro BNP levels at birth in DD-sIUGR, and to compare them with those of MD-sIUGR. Forty-one DD twin pairs admitted to our center between October 2007 and January 2013 were enrolled in this study and separated into two groups: nine twins with sIUGR (DD-sIUGR group) and 32 twins without sIUGR (DD without sIUGR group). Sixteen MD twins with sIUGR (MD-sIUGR group) served as positive controls. Serum NT-pro BNP levels at birth in DD-sIUGR [median 2,115 pg/ml (range, 443-6,590 pg/ml)] were significantly higher than in DD without sIUGR [1,080 pg/ml (range, 313-3,470 pg/ml); p=0.001], and significantly lower than in MD twins with sIUGR [4,520 pg/ml (range, 529-62,400 pg/ml); p=0.04]. Serum NT-pro BNP levels between larger and smaller DD co-twins were significantly correlated (r = 0.582; p<0.0001). In conclusion, serum NT-pro BNP levels at birth in DD twins with sIUGR were higher than those without, and lower than in MD twins with sIUGR.

  7. Perinatal characteristics and risk of polio among Swedish twins.

    PubMed

    Perng, Wei; Cnattingius, Sven; Iliadou, Anastasia; Villamor, Eduardo

    2012-05-01

    Prenatal exposure to adverse environmental conditions is related to increased adult mortality in regions where infections are highly prevalent, yet there is little evidence of the impact of perinatal conditions on the risk of severe infections throughout life. Using prospectively collected data from 21 604 like-sexed Swedish twins of known zygosity born in 1926-1958, we examined the risk of polio in relation to perinatal characteristics using cohort and nested co-twin case-control analyses. Polio incidence was determined through an interview in 1998, and linkage with the Swedish national inpatient and death registries. There were 133 cases of polio. In the cohort analysis, birth length, birthweight and head circumference were positively associated with polio risk. After adjustment for sex, birth year, gestational age at birth and within-twin pair correlations, twins of shortest length (<44 cm) had a 67% ([95% CI: 6%, 88%]; P=0.04) lower risk of polio compared with the reference group (47-49 cm). After additional adjustment for birth length, every 100-g increase in birthweight was related to a 34% increased risk of polio ([95% CI: -1%, 82%]; P=0.06), and every 10-mm increase in head circumference was related to a 17% greater risk of polio ([95% CI: 5%, 31%]; P=0.004). In co-twin control analyses among 226 disease-discordant twins, birth length, birthweight and head circumference were 0.3 cm (P=0.19), 84 g (P=0.07) and 3 mm (P=0.08) higher in cases than controls, respectively. Similar associations were observed among monozygotic (n=84) and dizygotic (n=142) twins. These findings suggest that early intrauterine growth restriction may be inversely related to the incidence of polio.

  8. Genetic regulation of immunoglobulin and specific antibody levels in twins reared apart.

    PubMed Central

    Kohler, P F; Rivera, V J; Eckert, E D; Bouchard, T J; Heston, L L

    1985-01-01

    We studied the effect of the same genetic but different environmental factors on total immunoglobulin and specific antibody levels in twins reared apart. Sera were analyzed from 26 monozygotic (MZ) and 10 dizygotic (DZ) twin pairs, who were separated on average 2 mo after birth and reared apart. Total IgM, IgG, and IgA were measured by single radial diffusion. Specific antibodies of each isotype to tetanus toxoid, and to polyvalent and type 14 pneumococcal capsular polysaccharides were measured by a solid-phase antigen-enzyme-labeled anti-Ig immunoassay. One-way analysis of variance showed intrapair total Ig and antibody levels to be more highly correlated in MZ compared with DZ twins. Our results indicate that genetic factors are more important than environment in regulating these humoral immune responses. PMID:4038983

  9. Heritability of pain catastrophizing and associations with experimental pain outcomes: a twin study.

    PubMed

    Trost, Zina; Strachan, Eric; Sullivan, Michael; Vervoort, Tine; Avery, Ally R; Afari, Niloofar

    2015-03-01

    This study used a twin paradigm to examine genetic and environmental contributions to pain catastrophizing and the observed association between pain catastrophizing and cold-pressor task (CPT) outcomes. Male and female monozygotic (n = 206) and dizygotic twins (n = 194) from the University of Washington Twin Registry completed a measure of pain catastrophizing and performed a CPT challenge. As expected, pain catastrophizing emerged as a significant predictor of several CPT outcomes, including cold-pressor Immersion Tolerance, Pain Tolerance, and Delayed Pain Rating. The heritability estimate for pain catastrophizing was found to be 37% with the remaining 63% of variance attributable to unique environmental influence. Additionally, the observed associations between pain catastrophizing and CPT outcomes were not found attributable to shared genetics or environmental exposure, which suggests a direct relationship between catastrophizing and experimental pain outcomes. This study is the first to examine the heritability of pain catastrophizing and potential processes by which pain catastrophizing is related to experimental pain response.

  10. [The Murcia Twin Registry. A resource for research on health-related behaviour].

    PubMed

    Ordoñana, Juan R; Sánchez Romera, Juan F; Colodro-Conde, Lucía; Carrillo, Eduvigis; González-Javier, Francisca; Madrid-Valero, Juan J; Morosoli-García, José J; Pérez-Riquelme, Francisco; Martínez-Selva, José M

    2017-03-08

    Genetically informative designs and, in particular, twin studies, are the most widely used methodology to analyse the relative contribution of genetic and environmental factors to inter-individual variability. These studies basically compare the degree of phenotypical similarity between monozygotic and dizygotic twin pairs. In addition to the traditional estimate of heritability, this kind of registry enables a wide variety of analyses which are unique due to the characteristics of the sample. The Murcia Twin Registry is population-based and focused on the analysis of health-related behaviour. The observed prevalence of health problems is comparable to that of other regional and national reference samples, which guarantees its representativeness. Overall, the characteristics of the Registry facilitate developing various types of research as well as genetically informative designs, and collaboration with different initiatives and consortia.

  11. The Role of Nature and Nurture for Individual Differences in Primary Emotional Systems: Evidence from a Twin Study

    PubMed Central

    Reuter, Martin; Spinath, Frank M.; Davis, Ken; Panksepp, Jaak

    2016-01-01

    The present study investigated for the first time the relative importance of genetics and environment on individual differences in primary emotionality as measured with the Affective Neuroscience Personality Scales (ANPS) by means of a twin-sibling study design. In N = 795 participants (n = 303 monozygotic twins, n = 172 dizygotic twins and n = 267 non-twin full siblings), moderate to strong influences of genetics on individual differences in these emotional systems are observed. Lowest heritability estimates are presented for the SEEKING system (33%) and highest for the PLAY system (69%). Further, multivariate genetic modeling was applied to the data showing that associations among the six ANPS scales were influences by both, a genetic as well as an environmental overlap between them. In sum, the study underlines the usefulness of the ANPS for biologically oriented personality psychology research. PMID:26999649

  12. The Role of Nature and Nurture for Individual Differences in Primary Emotional Systems: Evidence from a Twin Study.

    PubMed

    Montag, Christian; Hahn, Elisabeth; Reuter, Martin; Spinath, Frank M; Davis, Ken; Panksepp, Jaak

    2016-01-01

    The present study investigated for the first time the relative importance of genetics and environment on individual differences in primary emotionality as measured with the Affective Neuroscience Personality Scales (ANPS) by means of a twin-sibling study design. In N = 795 participants (n = 303 monozygotic twins, n = 172 dizygotic twins and n = 267 non-twin full siblings), moderate to strong influences of genetics on individual differences in these emotional systems are observed. Lowest heritability estimates are presented for the SEEKING system (33%) and highest for the PLAY system (69%). Further, multivariate genetic modeling was applied to the data showing that associations among the six ANPS scales were influences by both, a genetic as well as an environmental overlap between them. In sum, the study underlines the usefulness of the ANPS for biologically oriented personality psychology research.

  13. 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.

  14. Synesthesia in twins: incomplete concordance in monozygotes suggests extragenic factors.

    PubMed

    Bosley, Hannah G; Eagleman, David M

    2015-06-01

    Colored-sequence synesthesia (CSS) is a neurological condition in which sequential stimuli such as letters, numbers, or days of the week trigger simultaneous, involuntary color perception. Although the condition appears to run in families and several studies have sought a genetic link, the genetic contribution to synesthesia remains unclear. We conducted the first comparative twin study of CSS and found that CSS has a pairwise concordance of 73.9% in monozygotic twins, and a pairwise concordance of 36.4% in dizygotic twins. In line with previous studies, our results suggest a heritable element of synesthesia. However, consonant with the findings of previous single-pair case studies, our large sample size verifies that synesthesia is not completely conferred by genetics; if it were, monozygotic twins should have 100% concordance. These findings implicate a genetic mechanism of CSS that may work differently than previously thought: collectively, our data suggest that synesthesia is a heritable condition with incomplete penetrance that is substantially influenced by epigenetic and environmental factors.

  15. Twin Peaks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.

    The image was taken by the Imager for Mars Pathfinder (IMP) after its deployment on Sol 3. Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  16. Fetal Intra-Peritoneal Transfusion for the Management of Very Early Spontaneous Twin Anemia-Polycythemia Sequence in an Obese Patient With a Whole Anterior Placenta.

    PubMed

    Guenot, Cécile; Robyr, Romaine; Jastrow, Nicole; Vial, Yvan; Raio, Luigi; Baud, David

    2016-04-01

    Twin anemia-polycythemia sequence (TAPS) is a rare condition in monochorionic twin pregnancies. Small intertwin placental vascular communications allow transfusion, which results in a hemoglobin difference in the twins in the absence of oligohydramnios or polyhydramnios. We report here a case of TAPS diagnosed at 17 weeks' gestation in an obese patient (BMI 42) with a whole anterior placenta. The only possible treatment at this stage of pregnancy was intra-uterine transfusion (IUT), which was repeated weekly until photocoagulation of placental anastomoses was feasible. Fetoscopic laser surgery is the only curative treatment, but is challenging in TAPS because of the absence of polyhydramnios and the presence of minuscule anastomoses. An anterior placenta and high BMI can make the procedure even more challenging. This case report demonstrates that very early and rapidly progressing TAPS with technically complicated conditions (elevated BMI and anterior placenta) can be successfully managed with IUT until laser procedure is achievable.

  17. The higher frequency of IgA deficiency among Swedish twins is not explained by HLA haplotypes.

    PubMed

    Frankowiack, M; Kovanen, R-M; Repasky, G A; Lim, C K; Song, C; Pedersen, N L; Hammarström, L

    2015-01-01

    Serum immunoglobulin A (IgA) concentrations were determined in 12 600 adult Swedish twins, applying a high-throughput reverse-phase protein microarray technique. The prevalence of IgA deficiency (IgAD) was found to be 1:241 in monozygotic (MZ) twins and 1:198 in dizygotic (DZ) twins. Hence, the prevalence in twins is markedly elevated as compared with the normal Swedish adult population (1:600). The twins did not show a difference in the frequency of HLA haplotypes in comparison with almost 40 000 healthy Swedish controls. As expected, the risk-conveying HLA alleles A*01, B*08 and DRB1*01 were overrepresented among the IgAD twins and were also associated with significantly lower mean serum IgA concentrations in the twin cohort. In contrast, significantly higher mean IgA concentrations were found among individuals carrying the protective HLA alleles B*07 and DRB1*15. Exome sequencing data from two MZ twin pairs discordant for the deficiency showed no differences between the siblings. Model fitting analyses derived a heritability of 35% and indicate that genetic influences are modestly important for IgAD. The probandwise concordance rates for IgAD were found to be 31% for MZ and 13% for DZ twins.

  18. Twin-to-twin transfusion syndrome

    MedlinePlus Videos and Cool Tools

    ... causing an unequal exchange of blood. The recipient twin is at risk for heart failure receiving too much blood from ... its heart to work harder, while the donor twin is at risk for loss of blood. Laser surgery may be ...

  19. The Nature and Nurture of Melody: A Twin Study of Musical Pitch and Rhythm Perception.

    PubMed

    Seesjärvi, Erik; Särkämö, Teppo; Vuoksimaa, Eero; Tervaniemi, Mari; Peretz, Isabelle; Kaprio, Jaakko

    2016-07-01

    Both genetic and environmental factors are known to play a role in our ability to perceive music, but the degree to which they influence different aspects of music cognition is still unclear. We investigated the relative contribution of genetic and environmental effects on melody perception in 384 young adult twins [69 full monozygotic (MZ) twin pairs, 44 full dizygotic (DZ) twin pairs, 70 MZ twins without a co-twin, and 88 DZ twins without a co-twin]. The participants performed three online music tests requiring the detection of pitch changes in a two-melody comparison task (Scale) and key and rhythm incongruities in single-melody perception tasks (Out-of-key, Off-beat). The results showed predominantly additive genetic effects in the Scale task (58 %, 95 % CI 42-70 %), shared environmental effects in the Out-of-key task (61 %, 49-70 %), and non-shared environmental effects in the Off-beat task (82 %, 61-100 %). This highly different pattern of effects suggests that the contribution of genetic and environmental factors on music perception depends on the degree to which it calls for acquired knowledge of musical tonal and metric structures.

  20. What effect does classroom separation have on twins' behavior, progress at school, and reading abilities?

    PubMed

    Tully, Lucy A; Moffitt, Terrie E; Caspi, Avshalom; Taylor, Alan; Kiernan, Helena; Andreou, Penny

    2004-04-01

    We investigated the effects of classroom separation on twins' behavior, progress at school, and reading abilities. This investigation was part of a longitudinal study of a nationally-representative sample of twins (the E-risk Study) who were assessed at the start of school (age 5) and followed up (age 7). We examined three groups of twins: pairs who were in the same class at both ages; pairs who were in separate classes at both ages; and pairs who were in the same class at age 5, but separated by age 7. When compared to those not separated, those separated early had significantly more teacher-rated internalizing problems and those separated later showed more internalizing problems and lower reading scores. Monozygotic (MZ) twins showed more problems as a result of separation than dizygotic (DZ) twins. No group differences emerged for externalizing problems, ADHD or prosocial behaviors. The implications of the findings for parents and teachers of twins, and for school practices about separating twins, are discussed.

  1. Influence of genetic and environmental factors on oral diseases and function in aged twins.

    PubMed

    Kurushima, Y; Ikebe, K; Matsuda, K; Enoki, K; Ogata, S; Yamashita, M; Murakami, S; Hayakawa, K; Maeda, Y

    2015-01-01

    This study was conducted to quantify the genetic and environmental contributions to oral disease and function in twins. Participants were middle-aged and old twins, 116 monozygotic and 16 dizygotic pairs whose mean age was 66·1 ± 10·3 (SD) years. Number of teeth, percentage of decayed, filled and missing teeth and periodontal status were recorded as indicators of oral disease. The widths of upper and lower dental arch served as indicators of morphological figures. Furthermore, stimulated salivary flow rate, occlusal force and masticatory performance were measured as indicators of oral function. Univariate genetic analysis with monozygotic and dizygotic twin pairs was conducted to detect the fittest structural equation model of each outcome. Both number of teeth and periodontal status fitted the model composed of common environmental factor and unique environmental factor. Decayed, filled and missing teeth, morphological figures and measurements of oral function fitted the model composed of additive genetic factor and unique environmental factor. The model fitting of each measurement suggested that periodontal disease was mainly affected by environmental factors, while morphological figures and oral functions were influenced by both genetic and environmental factors.

  2. Investigating brain connectivity heritability in a twin study using diffusion imaging data

    PubMed Central

    Shen, Kai-Kai; Rose, Stephen; Fripp, Jurgen; McMahon, Katie L.; de Zubicaray, Greig I.; Martin, Nicholas G.; Thompson, Paul M.; Wright, Margaret J.; Salvado, Olivier

    2014-01-01

    Heritability of brain anatomical connectivity has been studied with diffusion-weighted imaging (DWI) mainly by modeling each voxel's diffusion pattern as a tensor (e.g., to compute fractional anisotropy), but this method cannot accurately represent the many crossing connections present in the brain. We hypothesized that different brain networks (i.e., their component fibers) might have different heritability and we investigated brain connectivity using High Angular Resolution Diffusion Imaging (HARDI) in a cohort of twins comprising 328 subjects that included 70 pairs of monozygotic and 91 pairs of dizygotic twins. Water diffusion was modeled in each voxel with a Fiber Orientation Distribution (FOD) function to study heritability for multiple fiber orientations in each voxel. Precision was estimated in a test–retest experiment on a sub-cohort of 39 subjects. This was taken into account when computing heritability of FOD peaks using an ACE model on the monozygotic and dizygotic twins. Our results confirmed the overall heritability of the major white matter tracts but also identified differences in heritability between connectivity networks. Inter-hemispheric connections tended to be more heritable than intra-hemispheric and cortico-spinal connections. The highly heritable tracts were found to connect particular cortical regions, such as medial frontal cortices, postcentral, paracentral gyri, and the right hippocampus. PMID:24973604

  3. Rapid Resolution of Polyhydramnios Foretells Circulatory Collapse for the Donor Twin in Feto-Fetal Transfusion Syndrome.

    PubMed

    López-Cepero, Ronald; Santoro, Joseph; de la Vega, Alberto

    2016-03-01

    Feto-fetal transfusion syndrome is a pathological process unique to diamniotic monochorionic pregnancies. It is the consequence of an unbalanced fetal blood flow through communicating vessels within a shared placenta. When it occurs, a polyuric, hypervolemic recipient twin co-exists with a hypovolemic oliguric donor. The presence of polyhydramnios or oligohydramnios is considered a poor prognostic indicator, whereas normal amniotic fluid volumes indicate a lack of clinically significant twintwin transfusion. In addition, the spontaneous normalization of amniotic fluid volume is usually seen as a favorable prognostic sign. Here, however, we present a case of feto-fetal transfusion in a 31 year-old primigravida at 19 week, in which the spontaneous normalization of amniotic fluid volume in the recipient twin preceded the death of the donor.

  4. Twin Jet

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda; Bozak, Rick

    2010-01-01

    Many subsonic and supersonic vehicles in the current fleet have multiple engines mounted near one another. Some future vehicle concepts may use innovative propulsion systems such as distributed propulsion which will result in multiple jets mounted in close proximity. Engine configurations with multiple jets have the ability to exploit jet-by-jet shielding which may significantly reduce noise. Jet-by-jet shielding is the ability of one jet to shield noise that is emitted by another jet. The sensitivity of jet-by-jet shielding to jet spacing and simulated flight stream Mach number are not well understood. The current experiment investigates the impact of jet spacing, jet operating condition, and flight stream Mach number on the noise radiated from subsonic and supersonic twin jets.

  5. Effect of birth parameters on retinal vascular caliber: the Twins Eye Study in Tasmania.

    PubMed

    Sun, Cong; Ponsonby, Anne-Louise; Wong, Tien Y; Brown, Shayne A; Kearns, Lisa S; Cochrane, Jenny; MacKinnon, Jane R; Ruddle, Jonathan B; Hewitt, Alex W; Liew, Gerald; Dwyer, Terence; Scurrah, Katrina; Mackey, David A

    2009-03-01

    Recent studies reported an association between smaller birth size and narrower retinal vascular caliber, but it remains unclear whether this association is attributed to confounding by shared environment or genetic factors. At a mean age of 9.3 years, 266 twins (49 monozygotic and 84 dizygotic pairs) in the Twins Eye Study in Tasmania underwent an ophthalmic examination including retinal photography. Retinal vascular caliber was measured using a validated protocol. The majority of these twins were also in the Tasmanian Infant Health Study, which prospectively collected data on birth parameters and antenatal maternal factors. We conducted the main analysis using linear mixed models, accounting for birth set clustering. Both the within-pair (-9.73; 95% CI: -14.68 to -4.77 microm per 5-cm decrease in birth length) and between-pair associations (-7.15; 95% CI: -11.54 to -3.01) with retinal arteriolar caliber were significant and of similar magnitude (difference in effect, P=0.61), after adjusting for age, sex, maternal smoking, mean arterial blood pressure, and other confounders. These associations remained within dizygotic and monozygotic pairs. Analyses of head circumference and retinal arteriolar caliber were similar to those of birth length (within-pair regression coefficient: -2.41; 95% CI: -5.09 to 0.28; between-pair regression coefficient: -2.60; 95% CI: -5.00 to -0.19). For birth weight, only a between-pair association was evident (-7.28; 95% CI: -13.07 to -1.48). This study demonstrates a consistent association between smaller birth size and narrower retinal arterioles in twins. The independent effect of shorter birth length on retinal arteriolar caliber supports a role for twin-specific supply line factors affecting fetal growth on vascular structure.

  6. Substantial Genetic Overlap between Schizotypy and Neuroticism: A Twin Study

    PubMed Central

    Macare, Christine; Bates, Timothy C.; Heath, Andrew C.; Martin, Nicholas G.; Ettinger, Ulrich

    2013-01-01

    Schizotypy is phenotypically associated with neuroticism. To reveal the origin of this association, we assessed 3349 (1449 monozygotic (MZ), 1105 dizygotic (DZ) same-sex and 795 DZ opposite-sex) twins on a 12-item version of Chapman’s Psychosis-Proneness Scales and the short-form of the Eysenck Personality Questionnaire-Revised as measures of schizotypy and neuroticism. A substantial proportion (.51 with 95% CI from .38 to .64) of the phenotypic correlation of .37 between neuroticism and the perceptual and ideational components of schizotypy was accounted for by shared genetic influences on these two traits. Moreover, a Cholesky decomposition including anhedonia, hypomania and impulsivity fully accounted for the heritable variance in perceptual and ideational components of schizotypy. These findings suggest a shared genetic etiology between neuroticism and perceptual and ideational components of schizotypy and affect future investigations on the etiology of these phenotypically overlapping traits and affective and psychotic disorders. PMID:22955548

  7. Diversity of Gut Microbiota Metabolic Pathways in 10 Pairs of Chinese Infant Twins

    PubMed Central

    Wang, Yan; Zhou, Jianli; Zhou, Wenhao

    2016-01-01

    Early colonization of gut microbiota in human gut is a complex process. It remains unclear when gut microbiota colonization occurs and how it proceeds. In order to study gut microbiota composition in human early life, the present study recruited 10 healthy pairs of twins, including five monozygotic (MZ) and five dizygotic (DZ) twin pairs, whose age ranged from 0 to 6 years old. 20 fecal samples from these twins were processed by shotgun metagenomic sequencing, and their averaged data outputs were generated as 2G per sample. We used MEGAN5 to perform taxonomic and functional annotation of the metagenomic data, and systematically analyzed those 20 samples, including Jaccard index similarity, principle component, clustering, and correlation analyses. Our findings indicated that within our study group: 1) MZ-twins share more microbes than DZ twins or non-twin pairs, 2) gut microbiota distribution is relatively stable at metabolic pathways level, 3) age represents the strongest factor that can account for variation in gut microbiota, and 4) a clear metabolic pathway shift can be observed, which speculatively occurs around the age of 1 year old. This research will serve as a base for future studies of gut microbiota-related disease research. PMID:27583441

  8. Evidence for nonadditive genetic effects on Eysenck Personality Scales in South Korean twins.

    PubMed

    Hur, Yoon-Mi

    2007-04-01

    While evidence supporting for nonadditive genetic influences on personality traits in Caucasian populations has been growing in recent years, twin studies that explored the existence of genetic nonadditivity in personality variation in Asian populations are still lacking. Seven hundred and sixty-five pairs of adolescent and young adult twins registered with the South Korean Twin Registry completed the 7 scales of the Eysenck Personality Scales through a mail survey. Maximum likelihood twin correlations were computed and model-fitting analyses were conducted. Monozygotic twin correlations were consistently higher than twice the dizygotic twin correlations for all 7 scales, suggesting pervasive influences of nonadditive genetic effects on personality traits in the South Korean population. Model-fitting analyses indicated that genetic nonadditivity is particularly important for the variation of Impulsivity, Venturesomeness, Empathy, Lie, and Psychoticism. According to the best fitting models, nonadditive genetic effects ranged from 34 to 49% for these scales. For Neuroticism and Extraversion, models that included an additive genetic component fit better than those including a nonadditive genetic variance component.

  9. Discordant Growth of Monozygotic Twins Starts at the Blastocyst Stage: A Case Study

    PubMed Central

    Noli, Laila; Capalbo, Antonio; Ogilvie, Caroline; Khalaf, Yacoub; Ilic, Dusko

    2015-01-01

    Summary Discordant growth is a common complication of monochorionic/diamniotic pregnancies; in approximately 50% of cases, the cause is unknown. The case presented here suggests that discordant growth of monozygotic twins could start during preimplantation development. Two inner cell masses (ICMs) within the same blastocyst may originate in uneven splitting of a single “parental” ICM, or the two ICMs may be formed independently de novo. We studied the transcriptomes of two morphologically distinct ICMs within a single blastocyst using high-resolution RNA sequencing. The data indicated that the two ICM were at different stages of development; one was in the earliest stages of lineage commitment, while the other had already differentiated into epiblast and primitive endoderm. IGF1-mediated signaling is likely to play a key role in ICM growth and to be the major driver behind these differences. PMID:26584541

  10. A core gut microbiome in obese and lean twins

    PubMed Central

    Turnbaugh, Peter J.; Hamady, Micah; Yatsunenko, Tanya; Cantarel, Brandi L.; Duncan, Alexis; Ley, Ruth E.; Sogin, Mitchell L.; Jones, William J.; Roe, Bruce A.; Affourtit, Jason P.; Egholm, Michael; Henrissat, Bernard; Heath, Andrew C.; Knight, Rob; Gordon, Jeffrey I.

    2008-01-01

    The human distal gut harbors a vast ensemble of microbes (the microbiota) that provide us with important metabolic capabilities, including the ability to extract energy from otherwise indigestible dietary polysaccharides1–6. Studies of a small number of unrelated, healthy adults have revealed substantial diversity in their gut communities, as measured by sequencing 16S rRNA genes6–8, yet how this diversity relates to function and to the rest of the genes in the collective genomes of the microbiota (the gut microbiome) remains obscure. Studies of lean and obese mice suggest that the gut microbiota affects energy balance by influencing the efficiency of calorie harvest from the diet, and how this harvested energy is utilized and stored3–5. To address the question of how host genotype, environmental exposures, and host adiposity influence the gut microbiome, we have characterized the fecal microbial communities of adult female monozygotic and dizygotic twin pairs concordant for leanness or obesity, and their mothers. Analysis of 154 individuals yielded 9,920 near full-length and 1,937,461 partial bacterial 16S rRNA sequences, plus 2.14 gigabases from their microbiomes. The results reveal that the human gut microbiome is shared among family members, but that each person’s gut microbial community varies in the specific bacterial lineages present, with a comparable degree of co-variation between adult monozygotic and dizygotic twin pairs. However, there was a wide array of shared microbial genes among sampled individuals, comprising an extensive, identifiable ‘core microbiome’ at the gene, rather than at the organismal lineage level. Obesity is associated with phylum-level changes in the microbiota, reduced bacterial diversity, and altered representation of bacterial genes and metabolic pathways. These results demonstrate that a diversity of organismal assemblages can nonetheless yield a core microbiome at a functional level, and that deviations from this

  11. Subjective wellbeing and longevity: a co-twin control study.

    PubMed

    Sadler, Michael E; Miller, Christopher J; Christensen, Kaare; McGue, Matt

    2011-06-01

    Mental health is increasingly defined not only by the absence of illness but by the presence of subjective well-being (SWB). Previous cohort studies have consistently shown that indicators of SWB predict favorable life outcomes, including better mental and somatic health, and longevity. The favorable effects associated with SWB have prompted new research aimed at raising happiness and wellbeing through individual interventions and public health initiatives. Standard observational studies of individual-level associations, however, are subject to potential confounding of exposure and outcome by shared genes and environment. The present study explored the association between SWB and increased longevity, using twin pair analyses to determine whether the association is consistent with causality or is due to genetic or environmental confounding. The study sample of 3,966 twins aged 70 or older, followed for a median time period of 9 years, was drawn from the population-based Longitudinal Study of Aging Danish Twins (LSADT). The association between SWB, operationalized as affect and life satisfaction, and all-cause mortality risk was examined using between-individual and within-pair survival analyses. As expected, at the individual level, SWB predicted increased longevity. Exposure effects were also present in unadjusted and adjusted within-pair analyses of 400 dizygotic (DZ) pairs and 274 monozygotic (MZ) pairs, indicating that SWB is associated with increased longevity independent of familial factors of genes and shared environment.

  12. A twin study of hyperactivity--II. The aetiological role of genes, family relationships and perinatal adversity.

    PubMed

    Goodman, R; Stevenson, J

    1989-09-01

    In a large representative sample of 13-year-old twins, monozygotic pairs were more alike than same-sex dizygotic pairs on objective measures of attentiveness and on parent and teacher ratings of hyperactivity. Comparison of recognized and unrecognized monozygotic pairs indicated that parents and teachers rated twins more similarly when the twins were perceived as "identical" rather than "non-identical". After allowing for this stereotyping, genetic effects accounted for approximately half of the explainable variance of hyperactivity and inattentiveness. Data from mixed-sex pairs did not support a 2-threshold genetic explanation for the male excess of hyperactivity. The link between adverse family factors and hyperactivity was weak. Perinatal adversity was not related to later hyperactivity.

  13. Twin studies of schizophrenia: from bow-and-arrow concordances to star wars Mx and functional genomics.

    PubMed

    Cardno, A G; Gottesman, I I

    2000-01-01

    Twin studies have been vital for establishing an important genetic contribution to the etiology of schizophrenia. The five newest studies since 1995 from Europe and Japan have confirmed earlier findings. They yielded probandwise concordance rates of 41-65% in monozygotic (MZ) pairs and 0-28% in dizygotic (DZ) pairs, and heritability estimates of approximately 80-85%. Twin studies are also valuable for investigating the etiological relationships between schizophrenia and other disorders, and the genetic basis of clinical heterogeneity within schizophrenia. Studies of discordant MZ pairs provide further insights into non-inherited factors that contribute to the multifactorial etiology of this disorder. More recently, twin studies have begun to be used to directly investigate molecular genetic and epigenetic processes underlying schizophrenia.

  14. A Chaotic Home Environment Accounts for the Association between Respect for Rules Disposition and Reading Comprehension: A Twin Study.

    PubMed

    Taylor, Jeanette; Hart, Sara A

    2014-10-01

    This study examined the association between socioemotional dispositions from the developmental propensity model and reading comprehension and whether those associations could be accounted for by level of chaos in the home. Data from 342 monozygotic and 333 same-sex dizygotic twin pairs age 7-13 years were used. A parent rated the twins on sympathy, respect for rules, negative emotionality, and daring and level of chaos in the twins' home. Reading comprehension was measured using a state-wide school assessment. Only respect for rules significantly and uniquely predicted reading comprehension. Biometric models indicated that respect for rules was positively associated with reading comprehension via the shared environment and home chaos accounted for a significant amount of that shared environmental variance even after controlling for family income. Children with higher respect for rules have better reading comprehension scores in school and this relationship owes partly to the level of chaos in the family home.

  15. Genetic and environmental influences on the continuous scales of the Myers-Briggs Type Indicator: an analysis based on twins reared apart.

    PubMed

    Bouchard, T J; Hur, Y M

    1998-04-01

    The Myers-Briggs Type Indicator was administered to a sample of 61 monozygotic twins reared apart (MZA), 49 dizygotic twins reared apart (DZA), and 92 spouses, who participated in the Minnesota Study of Twins Reared Apart (MISTRA) from 1979 to 1995. Twins' scores on the continuous scales were subjected to behavior genetic model-fitting procedures. Extraversion-Introversion and Thinking-Feeling yielded heritabilities of about .60, consisting largely of nonadditive genetic variance. Sensing-Intuition and Judgment-Perception yielded heritabilities of about .40, consisting largely of additive genetic variance. Spouse correlations for three of the four scales were near zero and not statistically significant; one spouse correlation (Sensing-Intuition) was modestly positive and statistically significant.

  16. Genetic Factors Explain Variation in the Age at Onset of Psoriasis: A Population-based Twin Study.

    PubMed

    Lønnberg, Ann Sophie; Skov, Lone; Duffy, David Lorenzo; Skytthe, Axel; Kyvik, Kirsten Ohm; Pedersen, Ole Birger; Thomsen, Simon Francis

    2016-01-01

    The aim of this study was to determine the age at onset of psoriasis in a population-based twin sample. Questionnaire-data in 10,725 twin pairs, 20-71 years of age, from the Danish Twin Registry, was collected, and analysed using survival regression analysis. Median age at onset was 25 and 28 years among women and men, respectively. The correlation between the ages was 0.84 (bootstrap standard error?=?0.044) in monozygotic twin pairs and 0.60 (0.051) in dizygotic twin pairs, permutation p?=?0.001. Age at onset of psoriasis in the index twin did not predict risk of psoriasis in the co-twin, hazard ratio (per year of later onset =?1.01 (0.99-1.03), p?=?0.434. In conclusion, these data support that the age at onset of psoriasis is, in part, an inherited property. Our results do not support that early-onset psoriasis is more genetically determined.

  17. Genetic and environmental influence on DNA strand break repair: a twin study.

    PubMed

    Garm, Christian; Moreno-Villanueva, Maria; Bürkle, Alexander; Larsen, Lisbeth Aagaard; Bohr, Vilhelm A; Christensen, Kaare; Stevnsner, Tinna

    2013-07-01

    Accumulation of DNA damage deriving from exogenous and endogenous sources has significant consequences for cellular survival, and is implicated in aging, cancer, and neurological diseases. Different DNA repair pathways have evolved in order to maintain genomic stability. Genetic and environmental factors are likely to influence DNA repair capacity. In order to gain more insight into the genetic and environmental contribution to the molecular basis of DNA repair, we have performed a human twin study, where we focused on the consequences of some of the most abundant types of DNA damage (single-strand breaks), and some of the most hazardous lesions (DNA double-strand breaks). DNA damage signaling response (Gamma-H2AX signaling), relative amount of endogenous damage, and DNA-strand break repair capacities were studied in peripheral blood mononuclear cells from 198 twins (94 monozygotic and 104 dizygotic). We did not detect genetic effects on the DNA-strand break variables in our study.

  18. Shared genetic influences on ADHD symptoms and very low-frequency EEG activity: a twin study

    PubMed Central

    Tye, Charlotte; Rijsdijk, Frühling; Greven, Corina U.; Kuntsi, Jonna; Asherson, Philip; McLoughlin, Gráinne

    2013-01-01

    Background ADHD is a common and highly heritable neurodevelopmental disorder with a complex aetiology. The identification of candidate intermediate phenotypes that are both heritable and genetically linked to ADHD may facilitate the detection of susceptibility genes and elucidate aetiological pathways. Very low-frequency (VLF; <0.5Hz) electroencephalographic (EEG) activity represents a promising indicator of risk for ADHD, but it is currently unclear whether it is heritable or genetically linked to the disorder. Methods Direct-current (DC)-EEG was recorded during a cognitive activation condition in 30 monozygotic and dizygotic adolescent twin pairs concordant or discordant for high ADHD symptom scores, and 37 monozygotic and dizygotic matched-control twin pairs with low ADHD symptom scores. Structural equation modelling was used to quantify the genetic and environmental contributions to the phenotypic covariance between ADHD and VLF activity. Results ADHD was significantly associated with reduced VLF power during cognitive activation, which suggests reduced synchronisation of widespread neuronal activity. VLF power demonstrated modest heritability (0.31) and the genetic correlation (−0.80) indicated a substantial degree of overlap in genetic influences on ADHD and VLF activity. Conclusions Altered VLF activity is a potential candidate intermediate phenotype of ADHD, which warrants further investigation of underlying neurobiological and genetic mechanisms. PMID:22118296

  19. X chromosome gene methylation in peripheral lymphocytes from monozygotic twins discordant for scleroderma

    PubMed Central

    Selmi, C; Feghali-Bostwick, C A; Lleo, A; Lombardi, S A; De Santis, M; Cavaciocchi, F; Zammataro, L; Mitchell, M M; LaSalle, J M; Medsger Jr, T; Gershwin, M E

    2012-01-01

    Scleroderma (SSc) is a rare connective tissue disease characterized by fibrosis, microvasculopathy and autoimmune features. The role of genetics is limited in SSc, as suggested by similar concordance rates in monozygotic and dizygotic twin pairs, while environmental factors may act through epigenetic changes, as demonstrated for specific genes. Further, sex chromosome changes have been reported in SSc and may explain the female preponderance. In the present study we compared the methylation profile of all X chromosome genes in peripheral blood mononuclear cells from monozygotic twins discordant (n = 7) and concordant (n = 1) for SSc. Methylated DNA immunoprecipitations from each discordant twin pair were hybridized to a custom-designed array included 998 sites encompassing promoters of all X chromosome genes and randomly chosen autosomal genes. Biostatistical tools identified sites with an elevated probability to be consistently hypermethylated (n = 18) or hypomethylated (n = 25) in affected twins. Identified genes include transcription factors (ARX, HSFX1, ZBED1, ZNF41) and surface antigens (IL1RAPL2, PGRMC1), and pathway analysis suggests their involvement in cell proliferation (PGK1, SMS, UTP14A, SSR4), apoptosis (MTM1), inflammation (ARAF) and oxidative stress (ENOX2). In conclusion, we propose that X chromosome genes with different methylation profiles in monozygotic twin pairs may constitute candidates for SSc susceptibility. PMID:22861365

  20. Prevalence of and Familial Influences on Purging Disorder in a Community Sample of Female Twins

    PubMed Central

    Munn-Chernoff, Melissa A.; Keel, Pamela K.; Klump, Kelly L.; Grant, Julia D.; Bucholz, Kathleen K.; Madden, Pamela A. F.; Heath, Andrew C.; Duncan, Alexis E.

    2014-01-01

    Objective Purging Disorder (PD) was recently included as an Otherwise Specified Feeding or Eating Disorder (OSFED) in the DSM-5; however, limited information is available on its prevalence, and its etiology is unknown. Method Data from 1790 monozygotic and 1440 dizygotic European American female twins (age range = 18 – 29 years) from the Missouri Adolescent Female Twin Study were used to investigate prevalence and familial influences for PD. A structured clinical interview assessed lifetime DSM-IV criteria for eating disorders and PD. After adjustment for age, twin correlations and biometrical twin models were used to estimate familial (i.e., genetic plus shared environmental) influences on PD. Results One hundred and twenty one (3.77%; 95% CI: 3.14, 4.49) women met criteria for lifetime PD. Twin correlations suggested that genetic, shared environmental, and nonshared environmental factors influenced liability to PD. Nonshared environmental factors accounted for 56% [35%, 79%] of the variance in PD. Although familial effects accounted for a significant proportion of variance (44% [21%, 65%]), it was not possible to disentangle the independent contributions of additive genetic effects (20% [0%, 65%]) and shared environmental effects (24% [0%, 57%]). Discussion PD is a prevalent form of eating pathology. Familial factors are relevant to the development of PD but do not demonstrate the magnitude of heritable factors found for other eating disorders. PMID:25808399

  1. Asymmetric twin Dark Matter

    SciTech Connect

    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 the cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC.

  2. Asymmetric twin Dark Matter

    SciTech Connect

    Farina, Marco

    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 the cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC.

  3. Cohort Profile: Swedish Twin Study on Prediction and Prevention of Asthma (STOPPA).

    PubMed

    Almqvist, Catarina; Örtqvist, Anne K; Ullemar, Vilhelmina; Lundholm, Cecilia; Lichtenstein, Paul; Magnusson, Patrik K E

    2015-06-01

    Asthma is a common childhood disease and several risk factors have been identified; however, the impact of genes and environment is not fully understood. The aim of the Swedish Twin study On Prediction and Prevention of Asthma (STOPPA) is to identify environmental (birth characteristics and early life) and genetic (including epigenetic) factors as determinants for asthmatic disease. Based on the Child and Adolescent Twin Study in Sweden (CATSS) (parental interview at 9 or 12 years, N ~23,900) and an asthma and/or wheezing algorithm, we identified a sample of monozygotic (MZ) and dizygotic (DZ) same-sexed twin pairs. The twin pairs were classified as asthma concordant (ACC), asthma discordant (ADC) and healthy concordant (HCC). A sample of 9- to 14-year-old twins and their parents were invited to participate in a clinical examination. Background characteristics were collected in questionnaires and obtained from the National Health Registers. A clinical examination was performed to test lung function and capacity (spirometry with reversibility test and exhaled nitric oxide) and collect blood (serology and DNA), urine (metabolites), feces (microbiota), and saliva (cortisol). In total, 376 twin pairs (752 individual twins) completed the study, response rate 52%. All participating twins answered the questionnaire and >90% participated in lung function testing, blood-, and saliva sampling. This article describes the design, recruitment, data collection, measures, and background characteristics, as well as ongoing and planned analyses in STOPPA. Potential gains of the study include the identification of biomarkers, the emergence of candidates for drug development, and new leads for prevention of asthma and allergic disease.

  4. Early onset alcohol use and self-harm: A discordant twin analysis

    PubMed Central

    Few, Lauren R.; Werner, Kimberly B.; Sartor, Carolyn E.; Trull, Timothy; Nock, Matthew K.; Bucholz, Kathleen K.; Deitz, Sarah K.; Glowinski, Anne L.; Martin, Nicholas G.; Nelson, Elliot C.; Statham, Dixie J.; Madden, Pamela A. F.; Heath, Andrew; Lynskey, Michael T.; Agrawal, Arpana

    2015-01-01

    Background Self-harm has considerable societal and economic costs and has been extensively studied in relation to alcohol involvement. Whereas early onset alcohol use (EAU) has been causally linked to maladaptive clinical outcomes, its association with self-harm is less well characterized. The current study aimed to further examine the link between EAU and both non-suicidal self-injury (NSSI) and suicide attempt (SA), and elucidate shared familial and causal/individual-specific pathways that explain this co-occurrence. Methods Using data from 6,082 Australian same-sex twin pairs (1,732 MZ and 1,309 DZ), ages 23-40, we examined prevalence rates of NSSI and SA among twin pairs concordant and discordant for EAU. Conditional logistic regression, controlling for early clinical covariates and the influence of zygosity on EAU, was used to examine the odds ratio (OR) of self-harm within twin pairs discordant for EAU. Results Prevalence rates of both NSSI and SA were highest among twin pairs concordant for EAU and for twins who reported EAU within discordant twin pairs. Results from discordant twin analyses revealed nearly four-fold increased odds of SA for the twin who endorsed EAU, and this OR was equal across monozygotic (MZ) and dizygotic (DZ) twins. EAU also was associated with elevated odds of NSSI (OR=7.62), although this was only the case for DZ twins in discordant pairs. Conclusions The equivalent increase in odds of SA for both MZ and DZ twins suggests that causal or individual-specific influences explain the link between EAU and SA. For NSSI, elevated odds for DZ twins and nonsignificant findings for MZ twins implicate correlated genetic factors in the association between EAU and NSSI. Future studies should test mechanisms through which EAU may causally influence SA, as well as examine whether genetic risk for third variables (e.g., negative urgency, stress reactivity) may explain the genetic overlap between EAU and NSSI. PMID:26463647

  5. Co-twin study of the effect of environment and dietary elements on acquisition of Helicobacter pylori infection.

    PubMed

    Malaty, H M; Graham, D Y; Isaksson, I; Engstrand, L; Pedersen, N L

    1998-10-15

    The rate of Helicobacter pylori infection is inversely related to socioeconomic status, and childhood is thought to be the major acquisition period. The authors investigated the importance of childhood environment in the acquisition of H. pylori infection. A cross-sectional study was conducted of monozygotic and dizygotic twins who were reared apart or reared together. Three hundred twins from a subregistry of the Swedish Twin Registry were studied. H. pylori status was evaluated by using an enzyme-linked immunosorbent assay for anti-H. pylori immunoglobulin G. Socioeconomic status during childhood was assessed on the basis of the density of the living conditions and the economic situation of the family that reared the twins. Current socioeconomic status was estimated by using a scale that combined income and education. Dietary elements that were studied included fat and fiber intake and ascorbic acid consumption. The density of the childhood home was consistently found to be significantly associated with the acquisition of H. pylori infection (p = 0.04). Among monozygotic twins reared apart and discordant for H. pylori status, affected twins were raised in homes under poorer socioeconomic conditions than those of their unaffected co-twins (p = 0.02). Additionally, infected twins consumed more ascorbic acid than their unaffected co-twins (p = 0.04). The finding of an effect of socioeconomic status during childhood on the acquisition of H. pylori among monozygotic twins who were reared apart and had an identical genetic makeup but not a common environment confirms the hypothesis that childhood acquisition of H. pylori infection is linked to hygiene practices.

  6. Medical history of discordant twins and environmental etiologies of autism

    PubMed Central

    Willfors, C; Carlsson, T; Anderlid, B-M; Nordgren, A; Kostrzewa, E; Berggren, S; Ronald, A; Kuja-Halkola, R; Tammimies, K; Bölte, S

    2017-01-01

    The environmental contributions to autism spectrum disorder (ASD) and their informative content for diagnosing the condition are still largely unknown. The objective of this study was to investigate associations between early medical events and ASD, as well as autistic traits, in twins, to test the hypothesis of a cumulative environmental effect on ASD risk. A total of 80 monozygotic (MZ) twin pairs (including a rare sample of 13 twin pairs discordant for clinical ASD) and 46 dizygotic (DZ) twin pairs with varying autistic traits, were examined for intra-pair differences in early medical events (for example, obstetric and neonatal factors, first year infections). First, differences in early medical events were investigated using multisource medical records in pairs qualitatively discordant for ASD. The significant intra-pair differences identified were then tested in relation to autistic traits in the remaining sample of 100 pairs, applying generalized estimating equations analyses. Significant association of the intra-pair differences in the MZ pairs were found for the cumulative load of early medical events and clinical ASD (Z=−2.85, P=0.004) and autistic traits (β=78.18, P=0.002), as well as infant dysregulation (feeding, sleeping abnormalities, excessive crying and worriedness), when controlling for intelligence quotient and attention deficit hyperactivity disorder comorbidity. The cumulative load of early medical events in general, and infant dysregulation in particular, may index children at risk of ASD owing to non-shared environmental contributions. In clinical practice, these findings may facilitate screening and early detection of ASD. PMID:28140403

  7. Sleep quality and body mass index: a co-twin study.

    PubMed

    Madrid-Valero, Juan J; Martínez-Selva, José M; Ordoñana, Juan R

    2017-01-19

    There is a consistent relationship between body mass index and sleep quality. However, the directionality and possible confounding factors of this relationship are unclear. Our aim is to confirm the association between sleep quality and body mass index, independent of possible genetic confounding, as well as to provide some indirect inferences about the directionality of this association. The co-twin study design was used to analyse the body mass index-sleep relationship in a sample of 2150 twins. We selected two parallel sub-samples of twins discordant for body mass index (n = 430 pairs), or discordant for sleep quality (n = 316 pairs). Sleep quality and body mass index showed an inverse relationship (b = 0.056, P = 0.032) in the global sample. When twins discordant for body mass index were selected, this association maintained a similar effect size and statistical significance, at all levels of the case-control analysis (all discordant pairs b = 0.173, P < 0.001; dizygotic twins b = 0.174, P = 0.002; monozygotic twins b = 0.173, P = 0.050). Nevertheless, when twin pairs were selected on the basis of their discordance for sleep quality, the association between body mass index and sleep quality appeared weaker and lost significance (b = 0.021, P = 0.508). The analyses including only dizygotic (b = 0.028, P = 0.526) or monozygotic (b = 0.001, P = 0.984) pairs produced similar non-significant results. Our results confirm the relationship between sleep quality and body mass index, even after applying high levels of control, including genetic factors. Moreover, this study suggests a possible directionality of this relationship, such that sleep quality would strongly affect body mass index, while the opposite would be less robust and consistent in non-clinical samples.

  8. Age at first sexual intercourse, genes, and social context: evidence from twins and the dopamine D4 receptor gene.

    PubMed

    Guo, Guang; Tong, Yuying

    2006-11-01

    We carried out two distinct types of genetic analysis with data from the National Longitudinal Study of Adolescent Health. The first was a non-DNA twin analysis using monozygotic (identical) and same-sex dizygotic (fraternal) twins. The second analysis investigates the association between age at first sexual intercourse and the 48-bp repeat polymorphism in the dopamine receptor D4 gene (DRD4). The twin analysis shows that MZ twins correlate their timing of first sex to a much greater extent than do the same-sex DZ twins. Our analysis of the polymorphisms in DRD4 indicates that those with an any-3R genotype experienced a risk of first sexual intercourse 23% (p = .016), 233% (p = .0001), 28% (p = .012), and 69% (p = .006) higher than those with an other/other (or any-4R) genotype in the all-ethnicities (n = 2,552), Asian, white, and Hispanic samples, respectively. The risk of first sex does not differ between the two genotypes in the African American sample. These results were obtained after adjusting the standard socioeconomic covariates, including gender, parental education, family structure, and community poverty in the regression model. Evidence from both twin and genetic-variant analyses points to a role of genes in the timing of first sexual intercourse.

  9. Delivery of twins.

    PubMed

    Hofmeyr, G J; Drakeley, A J

    1998-03-01

    The delivery of twins presents considerable challenges to the obstetric team, particularly in terms of decision-making, technical skills required and the need to respond quickly to changing circumstances. There is a serious lack of sound evidence upon which to base decisions concerning the method of delivery of twins. The trend towards the routine use of caesarean section is not supported by evidence of improved outcome for the infants, while maternal outcome is compromised. Specific circumstances that may have a bearing on the need for caesarean section include gestational age, presentation of the twins and chorionicity/amnionicity. Caesarean section does not eliminate the chance of fetal trauma during delivery, particularly for premature twins. The techniques of twin delivery, whether vaginal or by caesarean section, require thorough preparation for all possible eventualities, and skilled teamwork. Particular attention should be paid to emotional needs during labour, birth and afterwards, of the parents of twins.

  10. Separation of Craniopagus Twins.

    PubMed

    Johnson, Reuben; Weir, Philip

    2016-01-01

    Separation of craniopagus twins is fraught by ethical issues. The surgery is high risk and may involve the sacrifice of one twin. We review surgical successes in separation of craniopagus twins and consider ethical and legal concepts affecting the decision to undertake such procedures. Our discussion considers how Gillett's potentiality principle and the concept of moral permissibility may be used to arrive at fair and realistic decisions.

  11. 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.

  12. Relative role of genes and environment on BP: twin studies in Madras, India.

    PubMed

    Rao, R M; Reddy, G P; Grim, C E

    1993-10-01

    This study was conducted to test the feasibility of the twin research model in a developing country with diverse cultures and to understand the relative influence of genetic and environmental factors on BP variation among South Indians. This was a cross-sectional twin study of volunteers using a two-by-two factorial design for the analysis of quantitative traits. The factors were twin type (monozygotic and dizygotic) and sex (male and female). The study was conducted in Madras. Twenty-four pairs of twins were contacted for participation in the project. Of the 24 pairs we contacted, 91% (20) actually participated in our study. Among 20 sets we studied, 10 (50%) are males and 10 (50%) are females with an average age of 23 years. The mean SBP of this volunteer twin population was 115.18 +/- 1.27 mmHg and DBP was 68.53 +/- 1.41 mmHg. Analysis of dietary habits (vegetarian/nonvegetarian) showed that BP was greater (118.26 +/- 2.29/71.88 +/- 2.34 mmHg) in vegetarian twins than nonvegetarians (112.28 +/- 1.42/66.2 +/- 1.90 mmHg). Also a positive correlation between urinary excretion of calcium and BP was observed. The present study demonstrates that epidemiological research in a developing country like India is feasible and economical, using the twin research methodology. As observed in other populations, the major source of BP variation in the population appears to be predominantly under genetic control.

  13. Is Chronic Low Back Pain Associated with the Prevalence of Coronary Heart Disease when Genetic Susceptibility Is Considered? A Co-Twin Control Study of Spanish Twins

    PubMed Central

    Fernandez, Matt; Ordoñana, Juan R.; Hartvigsen, Jan; Ferreira, Manuela L.; Refshauge, Kathryn M.; Sánchez-Romera, Juan F.; Pinheiro, Marina B.; Simpson, Stephen J.; Hopper, John L.; Ferreira, Paulo H.

    2016-01-01

    Objective To investigate the chronic low back pain and coronary heart disease relationship, after adjusting for relevant confounders, including genetics. Methods In a cross-sectional design, 2148 twins were recruited from the Murcia Twin Registry, Spain. The exposure was chronic LBP and the outcomes were myocardial infarction and other coronary heart diseases—lifetime and in the last 2 years–based on standardized health-related questionnaires. First, logistic regression analysis investigated associations of the total sample followed by a matched co-twin control analyses, with all complete twin pairs discordant for chronic LBP utilised, separated for zygosity—dizygotic (DZ) and monozygotic (MZ) pairs, which adjusted for shared familial factors, including genetics. Results Chronic LBP pain is associated with lifetime myocardial infarction [odds ratio (OR) = 2.69, 95% confidence interval (CI) = 1.35–5.36], other coronary heart diseases over a lifetime (OR = 2.58, 95% CI: 1.69–3.93) and in the last two years (OR = 2.19, 95% CI: 1.33–3.60), while there was a borderline association with myocardial infarction in the last 2 years (OR = 2.64, 95% CI: 0.98–7.12). Although the magnitude of the association remained or increased in the co-twin control analyses, none reached statistical significance. Conclusion Chronic LBP is associated with a higher prevalence of myocardial infarction and coronary heart disease. It is possible that this association remains even when controlling for genetics and early shared environment, although this should be investigated with larger samples of twins discordant for LBP. PMID:27171210

  14. 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.

  15. A twin study of breastfeeding with a preliminary genome wide association scan

    PubMed Central

    Colodro-Conde, L.; Zhu, G.; Power, R. A.; Henders, A.; Heath, A.C.; Madden, P.A.F.; Montgomery, G.W.; Medland, S. E.; Ordoñana, J.R.; Martin, N.G.

    2015-01-01

    Breastfeeding has been an important survival trait during human history, though it has long been recognised that individuals differ in their exact breastfeeding behaviour. Here our aims were, first, to explore to what extent genetic and environmental influences contributed to the individual differences in breastfeeding behaviour; second, to detect possible genetic variants related to breastfeeding; and lastly, to test if the genetic variants associated with breastfeeding have been previously found to be related with breast size. Data were collected from a large community-based cohort of Australian twins, with 3,364 women for the twin modelling analyses and 1,521 of them included in the genome wide association study. Monozygotic twin correlations (rMZ = .52, 95% CI .46 – .57) were larger than dizygotic twin correlations (rDZ = .35, 95% CI .25 – .43) and the best-fitting model was the one composed by additive genetics and unique environmental factors, explaining 53% and 47% of the variance in breastfeeding behaviour, respectively. No breastfeeding-related genetic variants reached genome-wide significance. The polygenic risk score analyses showed no significant results, suggesting breast size does not influence breastfeeding. This study confers a replication of a previous one exploring the sources of variance of breastfeeding and, to our knowledge, is the first one to conduct a Genome-Wide Association Study on breastfeeding and look at the overlap with variants for breast size. PMID:25475840

  16. A twin and molecular genetics study of sleep paralysis and associated factors.

    PubMed

    Denis, Dan; French, Christopher C; Rowe, Richard; Zavos, Helena M S; Nolan, Patrick M; Parsons, Michael J; Gregory, Alice M

    2015-08-01

    Sleep paralysis is a relatively common but under-researched phenomenon. In this paper we examine prevalence in a UK sample and associations with candidate risk factors. This is the first study to investigate the heritability of sleep paralysis in a twin sample and to explore genetic associations between sleep paralysis and a number of circadian expressed single nucleotide polymorphisms. Analyses are based on data from the Genesis1219 twin/sibling study, a community sample of twins/siblings from England and Wales. In total, data from 862 participants aged 22-32 years (34% male) were used in the study. This sample consisted of monozygotic and dizygotic twins and siblings. It was found that self-reports of general sleep quality, anxiety symptoms and exposure to threatening events were all associated independently with sleep paralysis. There was moderate genetic influence on sleep paralysis (53%). Polymorphisms in the PER2 gene were associated with sleep paralysis in additive and dominant models of inheritance-although significance was not reached once a Bonferroni correction was applied. It is concluded that factors associated with disrupted sleep cycles appear to be associated with sleep paralysis. In this sample of young adults, sleep paralysis was moderately heritable. Future work should examine specific polymorphisms associated with differences in circadian rhythms and sleep homeostasis further in association with sleep paralysis.

  17. Does educational status impact adult mortality in Denmark? A twin approach.

    PubMed

    Madsen, Mia; Andersen, Anne-Marie Nybo; Christensen, Kaare; Andersen, Per Kragh; Osler, Merete

    2010-07-15

    To disentangle an independent effect of educational status on mortality risk from direct and indirect selection mechanisms, the authors used a discordant twin pair design, which allowed them to isolate the effect of education by means of adjustment for genetic and environmental confounding per design. The study is based on data from the Danish Twin Registry and Statistics Denmark. Using Cox regression, they estimated hazard ratios for mortality according to the highest attained education among 5,260 monozygotic and 11,088 dizygotic same-sex twin pairs born during 1921-1950 and followed during 1980-2008. Both standard cohort and intrapair analyses were conducted separately for zygosity, gender, and birth cohort. Educational differences in mortality were demonstrated in the standard cohort analyses but attenuated in the intrapair analyses in all subgroups but men born during 1921-1935, and no effect modification by zygosity was observed. Hence, the results are most compatible with an effect of early family environment in explaining the educational inequality in mortality. However, large educational differences were still reflected in mortality risk differences within twin pairs, thus supporting some degree of independent effect of education. In addition, the effect of education may be more pronounced in older cohorts of Danish men.

  18. Guidelines on Library Twinning.

    ERIC Educational Resources Information Center

    Doyle, Robert P., Comp.; Scarry, Patricia, Comp.

    This document serves as an overview of the many forms of library twinning, or formal exchanges of materials and/or staff between two institutions. Twinning can be reciprocal, but often involves a one-way arrangement whereby a library in a developing country receives a visit from a librarian of a developed country. Either way, both institutions can…

  19. Low Birth Weight in MZ Twins Discordant for Birth Weight is Associated with Shorter Telomere Length and lower IQ, but not Anxiety/Depression in Later Life.

    PubMed

    Strohmaier, Jana; van Dongen, Jenny; Willemsen, Gonneke; Nyholt, Dale R; Zhu, Gu; Codd, Veryan; Novakovic, Boris; Hansell, Narelle; Wright, Margaret J; Rietschel, Liz; Streit, Fabian; Henders, Anjali K; Montgomery, Grant W; Samani, Nilesh J; Gillespie, Nathan A; Hickie, Ian B; Craig, Jeffrey M; Saffery, Richard; Boomsma, Dorret I; Rietschel, Marcella; Martin, Nicholas G

    2015-04-01

    Shorter telomere length (TL) has found to be associated with lower birth weight and with lower cognitive ability and psychiatric disorders. However, the direction of causation of these associations and the extent to which they are genetically or environmentally mediated are unclear. Within-pair comparisons of monozygotic (MZ) and dizygotic (DZ) twins can throw light on these questions. We investigated correlations of within pair differences in telomere length, IQ, and anxiety/depression in an initial sample from Brisbane (242 MZ pairs, 245 DZ same sex (DZSS) pairs) and in replication samples from Amsterdam (514 MZ pairs, 233 DZSS pairs) and Melbourne (19 pairs selected for extreme high or low birth weight difference). Intra-pair differences of birth weight and telomere length were significantly correlated in MZ twins, but not in DZSS twins. Greater intra-pair differences of telomere length were observed in the 10% of MZ twins with the greatest difference in birth weight compared to the bottom 90% in both samples and also in the Melbourne sample. Intra-pair differences of telomere length and IQ, but not of TL and anxiety/depression, were correlated in MZ twins, and to a smaller extent in DZSS twins. Our findings suggest that the same prenatal effects that reduce birth weight also influence telomere length in MZ twins. The association between telomere length and IQ is partly driven by the same prenatal effects that decrease birth weight.

  20. Genetic and Environmental Contributions to Personality Trait Stability and Change Across Adolescence: Results From a Japanese Twin Sample.

    PubMed

    Kawamoto, Tetsuya; Endo, Toshihiko

    2015-10-01

    We examined developmental trends and sources of stability and change in adolescent personality by using twin data collected from 1981 to 2010 (273 monozygotic (MZ) and 48 dizygotic (DZ) twin pairs) from a secondary school affiliated with the University of Tokyo. Phenotypic analyses showed high rank-order stability and substantial mean-level increases in neuroticism and declines in extraversion over the adolescent years. Longitudinal bivariate genetic analyses revealed that the best-fitting model for adolescent personality includes additive genetic and non-shared environmental influences. Heritability estimates ranged approximately from 0.30 to 0.60. Additionally, three-year stability in adolescent personality was influenced mainly by genetic factors, and there were both genetic and environmental innovations in mid-adolescence. Our findings suggest that both genetic and environmental effects have significant roles in the etiology of personality development across adolescence.

  1. A longitudinal study on genetic and environmental influences on leisure time physical activity in the Finnish Twin Cohort.

    PubMed

    Aaltonen, Sari; Ortega-Alonso, Alfredo; Kujala, Urho M; Kaprio, Jaakko

    2010-10-01

    The purpose of this study was to examine changes in the contribution of genetic and environmental influences to leisure time physical activity among male and female twins over a 6-year follow-up. At baseline the sample comprised 4,280 monozygotic and 9,276 dizygotic twin individuals, and at follow-up 4,383 monozygotic and 9,439 dizygotic twin individuals. Participants were aged 18-54 years at baseline. Genetic modeling results showed that genetic influences on leisure time physical activity declined from baseline (44%) to follow-up (34%). Most of the genetic influences identified at baseline were present at followup (r(g) = 0.72). Specific environmental influences increased from baseline (56%) to follow-up (66%) while at follow-up new environmental time-specific influences were observed (r(e) = 0.23). The model with sex differences showed a higher estimate of genetic influences for men than women both at baseline (men 47% vs. women 42%) and at follow-up (men 38% vs. women 31%). The additive genetic correlation for this phenotype was greater for men (r(g) = 0.79) than women (r(g) = 0.64). The specific environmental influences were corresponding; at baseline men 53% and women 56% and at follow-up men 62 % and women 69%. The environmental correlations between the two time points were similar for men (r(e)= 0.21) and for women (r(e)= 0.24). In conclusion, in a sample of healthy twins most of the genetic influences on leisure time physical activity expressed at baseline were present at 6 years of follow-up. New specific environmental factors underlying follow-up leisure time physical activity were observed.

  2. 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.

  3. Are familial factors underlying the association between socioeconomic position and prescription medicine? A register-based study on Danish twins

    PubMed Central

    Madsen, Mia; Andersen, Per Kragh; Gerster, Mette; Andersen, Anne-Marie Nybo; Osler, Merete; Christensen, Kaare

    2013-01-01

    Objectives Although well established, the association between socioeconomic position and health and health behaviour is not clearly understood, and it has been speculated that familial factors, for example, dispositional factors or exposures in the rearing environment, may be underlying the association. The objective was to compare prescription fillings within twin pairs who are partly or fully genetically identical and share childhood exposures. Design Twin cohort study. Setting Denmark. Participants Data from the Danish Twin Registry were linked to registers in Statistics Denmark and the Danish Registry of Medicinal Product statistics. A total of 8582 monozygotic (MZ) and 15 788 dizygotic same sex (DZSS) twins were included. Outcome measures Number of prescription fillings during follow-up (1995–2005) was analysed according to education and income. Results of unpaired and intrapair analyses were compared. Results An inverse social gradient in filling of prescriptions for all-purpose and system-specific drugs was observed in the unpaired analyses. In the intrapair analyses, associations were attenuated some in DZSS and more in MZ twins. Filling of drugs targeting the nervous system was still strongly associated with income in the intrapair analyses. Conclusions Familial factors seem to account for part of the observed social inequality in filling of prescription medicine. PMID:24227869

  4. Are the educational differences in incidence of cardiovascular disease explained by underlying familial factors? A twin study.

    PubMed

    Madsen, Mia; Andersen, Per K; Gerster, Mette; Andersen, Anne-Marie N; Christensen, Kaare; Osler, Merete

    2014-10-01

    To isolate the effect of education from the influence of potential underlying factors, we investigated the association of education with the risk of cardiovascular disease (CVD) and ischemic heart disease (IHD) using twin data to adjust for familial factors shared within twins, including genetic make-up and childhood environment. The study was based on data from the Danish Twin Registry linked to administrative and heath registers in Statistics Denmark. A total of 11,968 monozygotic and 20,464 dizygotic same sexed twins were followed from 1980 to 2009, including more than 8000 events of CVD. Unpaired and intra-pair analyses were compared. In the unpaired analyses, an inverse educational gradient in CVD- and IHD risk was observed. This association was not replicated in the intra-pair analyses that control for shared familial factors exploiting that twins share their intrauterine- and childhood environment and are matched partly or fully on genetic setup. The attenuation of association of education with CVD and IHD in the intra-pair analyses suggests that shared familial factors account for a substantial part of the observed association of education with CVD and IHD in Denmark.

  5. 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…

  6. Circadian system heritability as assessed by wrist temperature: a twin study.

    PubMed

    Lopez-Minguez, Jesus; Ordoñana, Juan R; Sánchez-Romera, Juan F; Madrid, Juan A; Garaulet, Marta

    2015-02-01

    Previous research shows that wrist temperature (WT) is a good marker to assess the circadian system health in different circumstances. However, no studies have been performed in order to know the genetic component of this circadian marker. For this purpose, the aim was to determine, using classical twin models, the relative genetic and environmental influences on WT. The study was performed in 53 pairs of female twins (28 monozygotic (MZ) and 25 dizygotic (DZ)), with a body mass index 25.9 ± 3.78 and mean age 52 ± 6 years. The sample was selected from the Murcia Twin Register. Circadian patterns were studied by analyzing WT during one week every 10 min "Circadianware®". Genetic influences to WT variability were estimated by comparing correlations of MZ and DZ twin pairs and fitting genetic structural equation models to measured variables. MZ twins showed higher intra-pair correlations than DZ twins for most of the parameters. Genetic factors were responsible for between 46% and 70% of variance (broad sense heritability) in parameters such as mean temperature, mesor, acrophase, Rayleigh test, percentage of rhythmicity and five hours of maximum temperature. The pattern of correlations and the genetic models point to moderate to high heritability for most of the WT parameters, suggesting a relevant genetic influence. The presence of these genetic factors points to endogenicity as the main cause of the coincidence of the WT rhythms. However, some WT parameters are still dependent on environment to a relevant extent and, hence, more amenable to change through external interventions.

  7. 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.

  8. SUSY meets her twin

    NASA Astrophysics Data System (ADS)

    Katz, Andrey; Mariotti, Alberto; Pokorski, Stefan; Redigolo, Diego; Ziegler, Robert

    2017-01-01

    We investigate the general structure of mirror symmetry breaking in the Twin Higgs scenario. We show, using the IR effective theory, that a significant gain in fine tuning can be achieved if the symmetry is broken hardly. We emphasize that weakly coupled UV completions can naturally accommodate this scenario. We analyze SUSY UV completions and present a simple Twin SUSY model with a tuning of around 10% and colored superpartners as heavy as 2 TeV. The collider signatures of general Twin SUSY models are discussed with a focus on the extended Higgs sectors.

  9. LETTER TO THE EDITOR: Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion. Nonlinear decay of adult red blood cells

    NASA Astrophysics Data System (ADS)

    van Gemert, Martin J. C.; Pasman, Suzanne A.; van den Wijngaard, Jeroen P. H. M.; Lopriore, Enrico; Vandenbussche, Frank P. H. A.

    2008-07-01

    Recently, we derived equations relating the flow of adult red blood cells through a placental arterio-venous anastomosis with intra-uterine and post-natal measured adult hemoglobin concentrations. In this letter, we re-derived the equations, now including a more realistic nonlinear decay of adult red blood cells, and re-evaluated the measurement accuracy of the arterio-venous flow and the lifetime of the red blood cells.

  10. Adult monozygotic twins discordant for intra-uterine growth have indistinguishable genome-wide DNA methylation profiles

    PubMed Central

    2013-01-01

    Background Low birth weight is associated with an increased adult metabolic disease risk. It is widely discussed that poor intra-uterine conditions could induce long-lasting epigenetic modifications, leading to systemic changes in regulation of metabolic genes. To address this, we acquire genome-wide DNA methylation profiles from saliva DNA in a unique cohort of 17 monozygotic monochorionic female twins very discordant for birth weight. We examine if adverse prenatal growth conditions experienced by the smaller co-twins lead to long-lasting DNA methylation changes. Results Overall, co-twins show very similar genome-wide DNA methylation profiles. Since observed differences are almost exclusively caused by variable cellular composition, an original marker-based adjustment strategy was developed to eliminate such variation at affected CpGs. Among adjusted and unchanged CpGs 3,153 are differentially methylated between the heavy and light co-twins at nominal significance, of which 45 show sensible absolute mean β-value differences. Deep bisulfite sequencing of eight such loci reveals that differences remain in the range of technical variation, arguing against a reproducible biological effect. Analysis of methylation in repetitive elements using methylation-dependent primer extension assays also indicates no significant intra-pair differences. Conclusions Severe intra-uterine growth differences observed within these monozygotic twins are not associated with long-lasting DNA methylation differences in cells composing saliva, detectable with up-to-date technologies. Additionally, our results indicate that uneven cell type composition can lead to spurious results and should be addressed in epigenomic studies. PMID:23706164

  11. Twin delivery: how should the second twin be delivered?

    PubMed

    Olofsson, P; Rydhström, H

    1985-11-01

    In a series of 803 pairs of twins born between 1973 and 1982, 0.33% of second twins were delivered by cesarean section after vaginal delivery of the first twin. During the last year the frequency has increased to 7%, calling attention to the problem of declining obstetric skills and experience. This has caused us to update the routines of intrapartum management of twin gestations. In the present program only commonly available obstetric techniques are used. The potentially hazardous twin delivery is excluded from a trial of vaginal delivery. Hopefully, the program will help other obstetricians to decide in favor of vaginal delivery in selected twin gestations.

  12. Research understanding, attitude and awareness towards biobanking: a survey among Italian twin participants to a genetic epidemiological study

    PubMed Central

    Toccaceli, Virgilia; Fagnani, Corrado; Nisticò, Lorenza; D'Ippolito, Cristina; Giannantonio, Lorenzo; Brescianini, Sonia; Stazi, Maria Antonietta

    2009-01-01

    Background The Italian Twin Registry (ITR) has been carrying out several genetic-epidemiological studies. Collection and storage of biological material from study participants has recently increased in the light of biobanking development. Within this scenario, we aimed at investigating understanding, awareness and attitude towards blood/DNA donation of research participants. About these quite unknown dimensions more knowledge is needed from ethical and social perspectives. Methods Cross-sectional mail survey to explore three dimensions: (i) understanding of aims and method of a specific study, (ii) attitude (three ideas for donation: "moral duty", "pragmatism", "spontaneity") and (iii) awareness (i.e. the recall of having been asked to donate) towards blood/DNA donation for research, among all the Italian twins who had participated in Euroclot (n = 181), a large international genetic-epidemiological study. Multivariate models were applied to investigate the association of sex, age, education and modality of Euroclot recruitment (twins enrolled in the ITR and volunteers) with the targeted dimensions. Pair-wise twin concordance for the "pragmatic" attitude was estimated in monozygotic and dizygotic pairs. Results Response rate was 56% (99 subjects); 75.8% understood the Euroclot method, only 33.3% correctly answered about the study aim. A significantly better understanding of aim and method was detected in "volunteers". Graduated subjects were more likely to understand study aim. In the overall sample, the "pragmatic" attitude to blood donation reached 76.8%, and biobanking awareness 89.9%. The latter was significantly higher among women. Monozygotic twins were more concordant than dizygotic twins for the "pragmatic" attitude towards blood/DNA donation for research. Conclusion Level of understanding of aims and methods of a specific research project seems to vary in relation to modalities of approaching research; most of the twins are well aware of having been asked

  13. Paroxysmal exercise-induced dyskinesia, writer's cramp, migraine with aura and absence epilepsy in twin brothers with a novel SLC2A1 missense mutation.

    PubMed

    Urbizu, Aintzane; Cuenca-León, Ester; Raspall-Chaure, Miquel; Gratacòs, Margarida; Conill, Joan; Redecillas, Susana; Roig-Quilis, Manuel; Macaya, Alfons

    2010-08-15

    We report two monochorionic twins that progressively developed, between ages 5 and 10, a combination of episodic neurological disorders including paroxysmal exercise-induced dyskinesia, migraine without or with aura, absence seizures and writer's cramp. CSF/serum glucose ratio was moderately decreased in both patients. Mutational analysis of SLC2A1 gene identified a de novo heterozygous missense mutation in exon 4. This novel mutation has been previously showed to disrupt glucose transport in vitro. Both patients showed immediate and near-complete response to ketogenic diet. This clinical observation suggests that a high index of suspicion for GLUT1 deficiency syndrome is warranted in evaluating patients with multiple neurological paroxysmal events.

  14. The heritability of gender identity disorder in a child and adolescent twin sample.

    PubMed

    Coolidge, Frederick L; Thede, Linda L; Young, Susan E

    2002-07-01

    The heritability and prevalence of the gender identity disorder (GID) was examined, as well as its comorbidity with separation anxiety and depression, in a nonretrospective study of child and adolescent twins. The parents of 314 twins (ages 4-17 years; 96 monozygotic pairs [MZ] and 61 dizygotic [DZ] pairs) completed the Coolidge Personality and Neuropsychological Inventory (CPNI) containing a six-item DSM-IV-based GID scale. Prevalence of clinically significant GID symptomatology in the twin sample was estimated to be 2.3%. Univariate model fitting analyses were conducted using an ordinal transformation of the GID scale. The model that best described the data included a significant additive genetic component accounting for 62% of the variance and a nonshared environmental component accounting for the remaining 38% of the variance. Results suggested no heterogeneity in the parameter estimates resulting from age. The correlation between GID and depression was modest, but significant (r = .20; P < .05), whereas the correlation between GID and separation anxiety was nonsignificant (P > .05). Overall, the results support the hypothesis that there is a strong heritable component to GID. The findings may also imply that gender identity may be much less a matter of choice and much more a matter of biology.

  15. Causes and consequences of obesity: the contribution of recent twin studies.

    PubMed

    Naukkarinen, J; Rissanen, A; Kaprio, J; Pietiläinen, K H

    2012-08-01

    Obesity is a genetically complex disorder that produces a myriad of health problems. Most of the recognized complications of obesity are not only strongly influenced by lifestyle factors, but also present with independent genetic predispositions that are notoriously difficult to disentangle in humans. Most studies on the causes and consequences of acquired obesity are encumbered by the incomplete ability to control for genetic influences. However, utilizing a unique experiment of nature, namely monozygotic twins (MZ) discordant for obesity as 'clonal controls' of obese and non-obese individuals has enabled the fine characterization of the effects and possible antecedents of acquired obesity while controlling for the genetic background, as well as pointed to novel obesity predisposing candidate genes. This review is a distillation of the findings from more than 10 years of research done in an exceptionally well-characterized collection of MZ and dizygotic (DZ) twins, based on the Finnish Twin Cohorts. Topics covered include the nature of development of obesity from the childhood onwards, the role of exercise in modifying the genetic susceptibility, the resulting inflammatory, prediabetic and preatherosclerotic changes in whole body and adipose tissue physiology, as well as the newest insights provided by the omics revolution.

  16. From alcohol initiation to tolerance to problems: Discordant twin modeling of a developmental process.

    PubMed

    Deutsch, Arielle R; Slutske, Wendy S; Lynskey, Michael T; Bucholz, Kathleen K; Madden, Pamela A F; Heath, Andrew C; Martin, Nicholas G

    2016-07-15

    The current study examined a stage-based alcohol use trajectory model to test for potential causal effects of earlier drinking milestones on later drinking milestones in a combined sample of two cohorts of Australian monozygotic and same-sex dizygotic twins (N = 7,398, age M = 30.46, SD = 2.61, 61% male, 56% monozygotic twins). Ages of drinking, drunkenness, regular drinking, tolerance, first nontolerance alcohol use disorder symptom, and alcohol use disorder symptom onsets were assessed retrospectively. Ages of milestone attainment (i.e., age-of-onset) and time between milestones (i.e., time-to-event) were examined via frailty models within a multilevel discordant twin design. For age-of-onset models, earlier ages of onset of antecedent drinking milestones increased hazards for earlier ages of onset for more proximal subsequent drinking milestones. For the time-to-event models, however, earlier ages of onset for the "starting" milestone decreased risk for a shorter time period between the starting and the "ending" milestone. Earlier age of onset of intermediate milestones between starting and ending drinking milestones had the opposite effect, increasing risk for a shorter time period between the starting and ending milestones. These results are consistent with a causal effect of an earlier age of drinking milestone onset on temporally proximal subsequent drinking milestones.

  17. Genetic pleiotropy between asthma and obesity in a community-based sample of twins

    PubMed Central

    Hallstrand, Teal S.; Fischer, Mary E.; Wurfel, Mark M.; Afari, Niloofar; Buchwald, Dedra; Goldberg, Jack

    2007-01-01

    Background Asthma and obesity are common conditions that are strongly associated. This association might be due to shared genetic or environmental causes. Objective We sought to determine whether a shared genetic cause is responsible for the association between asthma and obesity and to estimate the magnitude of shared genetic cause. Methods The analyses were performed with 1001 monozygotic and 383 dizygotic same-sex twin pairs within the University of Washington Twin Registry. The presence of asthma was determined by self-report of a physician diagnosis of asthma, and body mass index (BMI) was calculated by using self-reported height and weight. Obesity was defined as a BMI of 30 or greater. The association between asthma and BMI was assessed by means of mixed-effects ordinal regression. Twin correlations examined the association of asthma and obesity. Univariate and bivariate structural equation models estimated the components of variance attributable to genetic and environmental effects. Results A strong association between asthma and BMI was identified in the sample population (P < .001). Substantial heritability was detected for asthma (53%) and obesity (77%), which is indicative of additive genetic influences on each disorder. The best-fitting model of shared components of variance indicated that 8% of the genetic component of obesity is shared with asthma. Conclusion The covariation between obesity and asthma is predominantly caused by shared genetic risk factors for both conditions. PMID:16337451

  18. Path analytic, sib-pair linkage and co-twin control studies of asthma and atopy

    SciTech Connect

    Duffy, D.L.; Healey, S.C.; Martin, N.G.

    1994-09-01

    Asthma and atopy are complex traits with multifactorial determinants, and require appropriate choice of phenotypes and analyses, including a linkage analysis of the putative 11q atopy locus. Participants in a large registry-based twin study of asthma were invited to take part in clinical testing. A total of 863 individuals including 419 complete twin pairs (where one or both members reported a history of wheeze) underwent histamine inhalation challenge, allergen skin prick testing, and venesection. Total serum immunoglobulin E (IgE) and bronchial responsiveness (BR) to histamine were highest in those who had wheezed most recently, and whose skin tests demonstrated allergy to house dust mite, cockroach, and rye grass. In ascertainment-corrected path analyses (FISHER), the heritability of IgE and BR were both 60%. Monozygotic (MZ) co-twin control analyses suggested house dust mite sensitization was the single strongest environmentally controlled risk factor for wheeze, while path analyses suggested genetic determination. In dizygotic (DZ) co-twin control analyses, sensitization to grasses was also an important predictor, suggesting pollinosis to be genetically correlated with wheezing, rather than causative. Multivariate path analyses suggested separate (correlated) genetic factors for BR, IgE, and allergy to house dust mite. A sib-pair (Haseman-Elston) linkage analysis of 220 DZ twin pairs did not support linkage to the high-affinity IgE receptor beta-subunit gene on 11q13 of atopy or BR. More recent linkage analyses that include parental genotyping will also be discussed. We conclude that the atopic phenotype consists of a number of traits with specific genetic allergens. Exposure to particular allergens can then cause specific outcomes, such as asthma.

  19. Familial and environmental influences on brain volumes in twins with schizophrenia

    PubMed Central

    Picchioni, Marco M.; Rijsdijk, Fruhling; Toulopoulou, Timothea; Chaddock, Christopher; Cole, James H.; Ettinger, Ulrich; Oses, Ana; Metcalfe, Hugo; Murray, Robin M.; McGuire, Philip

    2017-01-01

    Background Reductions in whole brain and grey matter volumes are robust features of schizophrenia, yet their etiological influences are unclear. Methods We investigated the association between the genetic and environmental risk for schizophrenia and brain volumes. Whole brain, grey matter and white matter volumes were established from structural MRIs from twins varying in their zygosity and concordance for schizophrenia. Hippocampal volumes were measured manually. We conducted between-group testing and full genetic modelling. Results We included 168 twins in our study. Whole brain, grey matter, white matter and right hippocampal volumes were smaller in twins with schizophrenia. Twin correlations were larger for whole brain, grey matter and white matter volumes in monozygotic than dizygotic twins and were significantly heritable, whereas hippocampal volume was the most environmentally sensitive. There was a significant phenotypic correlation between schizophrenia and reductions in all the brain volumes except for that of the left hippocampus. For whole brain, grey matter and the right hippocampus the etiological links with schizophrenia were principally associated with the shared familial environment. Lower birth weight and perinatal hypoxia were both associated with lower whole brain volume and with lower white matter and grey matter volumes, respectively. Limitations Scan data were collected across 2 sites, and some groups were modest in size. Conclusion Whole brain, grey matter and right hippocampal volume reductions are linked to schizophrenia through correlated familial risk (i.e., the shared familial environment). The degree of influence of etiological factors varies between brain structures, leading to the possibility of a neuroanatomically specific etiological imprint. PMID:28245176

  20. Association between dietary fat intake and insulin resistance in Chinese child twins.

    PubMed

    Huang, Tao; Beaty, Terri; Li, Ji; Liu, Huijuan; Zhao, Wei; Wang, Youfa

    2017-01-01

    Dietary fat intake is correlated with increased insulin resistance (IR). However, it is unknown whether gene-diet interaction modulates the association. This study estimated heritability of IR measures and the related genetic correlations with fat intake, and tested whether dietary fat intake modifies the genetic influence on type 2 diabetes (T2D)-related traits in Chinese child twins. We included 622 twins aged 7-15 years (n 311 pairs, 162 monozygotic (MZ), 149 dizygotic (DZ)) from south-eastern China. Dietary factors were measured using FFQ. Structural equation models were fit using Mx statistical package. The intra-class correlation coefficients for all traits related to T2D were higher for MZ twins than for DZ twins. Dietary fat and fasting serum insulin (additive genetic correlation (r A) 0·20; 95 % CI 0·08, 0·43), glucose (r A 0·12; 95 % CI 0·01, 0·40), homoeostasis model of assessment-insulin resistance (Homa-IR) (r A 0·22; 95 % CI 0·10, 0·50) and the quantitative insulin sensitivity check index (Quicki) (r A -0·22; 95 % CI -0·40, 0·04) showed strong genetic correlations. Heritabilities of dietary fat intake, fasting glucose and insulin were estimated to be 52, 70 and 70 %, respectively. More than 70 % of the phenotypic correlations between dietary fat and insulin, glucose, Homa-IR and the Quicki index appeared to be mediated by shared genetic influence. Dietary fat significantly modified additive genetic effects on these quantitative traits associated with T2D. Analysis of Chinese twins yielded high estimates of heritability of dietary fat intake and IR. Genetic factors appear to contribute to a high proportion of the variance for both insulin sensitivity and IR. Dietary fat intake modifies the genetic influence on blood levels of insulin and glucose, Homa-IR and the Quicki index.

  1. Genetic and environmental effects on same-sex sexual behavior: a population study of twins in Sweden.

    PubMed

    Långström, Niklas; Rahman, Qazi; Carlström, Eva; Lichtenstein, Paul

    2010-02-01

    There is still uncertainty about the relative importance of genes and environments on human sexual orientation. One reason is that previous studies employed self-selected, opportunistic, or small population-based samples. We used data from a truly population-based 2005-2006 survey of all adult twins (20-47 years) in Sweden to conduct the largest twin study of same-sex sexual behavior attempted so far. We performed biometric modeling with data on any and total number of lifetime same-sex sexual partners, respectively. The analyses were conducted separately by sex. Twin resemblance was moderate for the 3,826 studied monozygotic and dizygotic same-sex twin pairs. Biometric modeling revealed that, in men, genetic effects explained .34-.39 of the variance, the shared environment .00, and the individual-specific environment .61-.66 of the variance. Corresponding estimates among women were .18-.19 for genetic factors, .16-.17 for shared environmental, and 64-.66 for unique environmental factors. Although wide confidence intervals suggest cautious interpretation, the results are consistent with moderate, primarily genetic, familial effects, and moderate to large effects of the nonshared environment (social and biological) on same-sex sexual behavior.

  2. The influence of heritability, neuroticism, maternal warmth and media use on disordered eating behaviors: a prospective analysis of twins.

    PubMed

    Ferguson, Christopher J; Muñoz, Monica E; Winegard, Ben; Winegard, Bo

    2012-09-01

    The relative impact of genetic and social influences on disordered eating behaviors (DEB) including binging, purging, excessive dieting and negative self-evaluations about weight remain an issue of debate. The current study sought to examine the relative influence of genetic and social influences on DEB. A 7-year prospective analysis of 580 monozygotic (MZ) and dizygotic (DZ) twins was conducted. Estimates of heritability of DEB were obtained using the DF Analysis Model. Regression equations revealed the relative predictive value of sibling's DEB, neurotic personality, maternal warmth and television and video game exposure on DEB. Heritability estimates for DEB were 0.40 for females and 0.48 for males. Among MZ and DZ twin pairs, female sex, neurotic personality and a genetic variable component, but not maternal warmth or school related problems, predicted DEB. Contrary to the expectations of media effects theory, greater media use was associated with lower DEB among DZ twins and had no influence on MZ twins. These results indicate that DEB is highly heritable and that personality variables may play an important role in the formation of DEB. This suggests that it is important to control for genetic variables when analyzing risk factors for DEB.

  3. Pain Sensitivity and Opioid Analgesia: A Pharmacogenomic Twin Study

    PubMed Central

    Angst, Martin S.; Phillips, Nicholas G.; Drover, David R.; Tingle, Martha; Ray, Amrita; Swan, Gary E.; Lazzeroni, Laura C.; Clark, J. David

    2012-01-01

    Opioids are the cornerstone medication for the management of moderate to severe pain. Unfortunately, vast inter-individual differences in dose requirements complicate their effective and safe clinical use. Mechanisms underlying such differences are incompletely understood, are likely multifactorial, and include genetic and environmental contributions. While accumulating evidence suggests that variants of several genes account for some of the observed response variance, the relative contribution of these factors remains unknown. This study used a twin paradigm to provide a global estimate of the genetic and environmental contributions to inter-individual differences in pain sensitivity and analgesic opioid effects. Eighty one monozygotic and 31 dizygotic twin pairs successfully underwent a computer-controlled infusion with the muopioid agonist alfentanil in a single occasion, randomized, double-blind and placebo-controlled study design. Pain sensitivity and analgesic effects were assessed with experimental heat and cold pressor pain models along with important covariates including demographic factors, depression, anxiety, and sleep quality. Significant heritability was detected for cold pressor pain tolerance and opioid-mediated elevations in heat and cold pressor pain thresholds. Genetic effects accounted for 12–60% of the observed response variance. Significant familial effects accounting for 24–32% of observed variance were detected for heat and cold pressor pain thresholds and opioid-mediated elevation in cold pressor pain tolerance. Significant covariates included age, gender, race, education, and anxiety. Results provide a strong rationale for more detailed molecular genetic studies to elucidate mechanisms underlying inter-individual differences in pain sensitivity and analgesic opioid responses. Such studies will require careful consideration of the studied pain phenotype. PMID:22444188

  4. Maternal nutrition in twin pregnancy.

    PubMed

    Campbell, D M; MacGillivray, I; Tuttle, S

    1982-01-01

    Energy and protein intake as measured by 24-hour urinary nitrogen values are similar in twin and singleton pregnancies. The relationship between urinary nitrogen and nitrogen intake is equally significant in twin and singleton pregnancies. Dietary zinc, copper, and iron are not different in women with twins, nor are the levels of these elements in plasma. These observations are surprising in view of the extra fetal demands on the mother and the different adaptation of twin pregnancies.

  5. Salicylate Metabolism in Twins

    PubMed Central

    Furst, Daniel E.; Gupta, Niroo; Paulus, Harold E.

    1977-01-01

    To evaluate the contribution of genetic influences on the individual variation in plateau serum salicylate levels, salicylate metabolism was studied in seven pairs of identical and six pairs of fraternal twins. Under the conditions of this study, after a single i.v. dose (40 mg/kg) of sodium salicylate, the serum salicylate concentration versus time curve approximated a straight line on linear coordinates (appeared approximately zero order). The slopes of the decay curves ranged between 0.64 and 1.02. The intrapair variation for identical twin pairs was significantly less than for fraternal twin pairs (P = 0.044). Likewise pleateau serum salicylic acid concentrations (milligrams/deciliter) and total salicylic acid excretion rate after multiple doses demonstrated significantly less intrapair variation for identical twins than for fraternal twins (P = 0.043 and 0.006). Plateau salicylurate excretion (milligram/kilogram per hour) differences after multiple dosing had a P = 0.067. Michaelis-Menton constant for salicylurate formation and hours to 50% excretion after the i.v. dose were not different when comparing identical and nonidentical twins. Salicylurate formation rates were increased after 3 days of oral therapy, and this induction phenomenon may account for much of the apparent discrepancy between genetic influences on salicylurate formation rates observed after single and multiple dose salicylate administration. This study suggests that the plateau concentration of serum salicylate varies among individuals given the same weight-adjusted dose in part because of genetically determined variations in their metabolism of salicylate. PMID:559691

  6. Twin Quintuplets in CVD Diamond

    DTIC Science & Technology

    1992-08-26

    microscopy (HRTEM). We conclude that the twin quintuplets have two main morphologies. The first consists of four Sigma = 3 twin boundaries and one...slightly more than the 70.53 deg tilt of a Sigma = 3 boundary. These grain boundaries and the conventional diamond lattice twin boundaries are the only types of boundaries that we have observed in CVD diamond.

  7. A case study of recipient twin surviving complications of twin-to-twin transfusion syndrome.

    PubMed

    Squires, Linda Sharee

    2013-10-01

    Twin-to-twin transfusion syndrome (TTTS) has a high rate of mortality and morbidity. This article describes the clinical course of a recipient twin in a case of TTTS. The twin was on long-term respiration support and survived two resuscitations, pneumothorax, chest tube placement, blood exchange, necrotizing enterocolitis and corrective surgery. This case demonstrates that the effective use of a collaborative, multidisciplinary care approach between two hospitals can result in a newborn surviving a severe case of TTTS.

  8. Continuity of Genetic and Environmental Influences on Cognition across the Life Span: A Meta-Analysis of Longitudinal Twin and Adoption Studies

    PubMed Central

    Tucker-Drob, Elliot M.; Briley, Daniel A.

    2014-01-01

    The longitudinal rank-order stability of cognitive ability increases dramatically over the lifespan. Multiple theoretical perspectives have proposed that genetic and/or environmental mechanisms underlie the longitudinal stability of cognition, and developmental trends therein. However, the patterns of stability of genetic and environmental influences on cognition over the lifespan largely remain poorly understood. We searched for longitudinal studies of cognition that reported raw genetically-informative longitudinal correlations or parameter estimates from longitudinal behavior genetic models. We identified 150 combinations of time points and measures from 15 independent longitudinal samples. In total, longitudinal data came from 4,538 monozygotic twin pairs raised together, 7,777 dizygotic twin pairs raised together, 34 monozygotic twin pairs raised apart, 78 dizygotic twin pairs raised apart, 141 adoptive sibling pairs, and 143 non-adoptive sibling pairs, ranging in age from infancy through late adulthood. At all ages, cross-time genetic correlations and shared environmental correlations were substantially larger than cross-time nonshared environmental correlations. Cross-time correlations for genetic and shared environmental components were low during early childhood, increased sharply over child development, and remained relatively high from adolescence through late adulthood. Cross-time correlations for nonshared environmental components were low across childhood and increased gradually to moderate magnitudes in adulthood. Increasing phenotypic stability over child development was almost entirely mediated by genetic factors. Time-based decay of genetic and shared environmental stability was more pronounced earlier in child development. Results are interpreted in reference to theories of gene-environment interaction and correlation. PMID:24611582

  9. Continuity of genetic and environmental influences on cognition across the life span: a meta-analysis of longitudinal twin and adoption studies.

    PubMed

    Tucker-Drob, Elliot M; Briley, Daniel A

    2014-07-01

    The longitudinal rank-order stability of cognitive ability increases dramatically over the life span. Theoretical perspectives differ in their emphasis on genetic mechanisms in explaining the longitudinal stability of cognition and how stability changes with development. However, the patterns of stability of genetic and environmental influences on cognition over the life span remain poorly understood. We searched for longitudinal studies of cognition that reported raw genetically informative longitudinal correlations or parameter estimates from longitudinal behavior genetic models. We identified 150 combinations of time points and measures from 15 independent longitudinal samples. In total, longitudinal data came from 4,548 monozygotic twin pairs raised together, 7,777 dizygotic twin pairs raised together, 34 monozygotic twin pairs raised apart, 78 dizygotic twin pairs raised apart, 141 adoptive sibling pairs, and 143 nonadoptive sibling pairs, ranging in age from infancy through late adulthood. At all ages, cross-time genetic correlations and shared environmental correlations were substantially larger than cross-time nonshared environmental correlations. Cross-time correlations for genetic and shared environmental components were, respectively, low and moderate during early childhood, increased sharply over child development, and remained high from adolescence through late adulthood. Cross-time correlations for nonshared environmental components were low across childhood and gradually increased to moderate magnitudes in adulthood. Increasing phenotypic stability over child development was almost entirely mediated by genetic factors. Time-based decay of genetic and shared environmental stability was more pronounced earlier in child development. Results are interpreted in reference to theories of gene-environment correlation and interaction.

  10. 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.

  11. Perinatal chikungunya in twins

    PubMed Central

    Karthiga, Vikneswari; Kommu, Peter Prasanth Kumar; Krishnan, Lalitha

    2016-01-01

    We report a case of vertically transmitted chikungunya infection in heterozygous twin neonates presenting as seizures, encephalopathy, midfacial hyperpigmentation, anemia, and thrombocytopenia. This could be considered as a rare cause of neonatal seizure and identification would help in appropriate management. PMID:27857791

  12. 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.

  13. Twin Signature Schemes, Revisited

    NASA Astrophysics Data System (ADS)

    Schäge, Sven

    In this paper, we revisit the twin signature scheme by Naccache, Pointcheval and Stern from CCS 2001 that is secure under the Strong RSA (SRSA) assumption and improve its efficiency in several ways. First, we present a new twin signature scheme that is based on the Strong Diffie-Hellman (SDH) assumption in bilinear groups and allows for very short signatures and key material. A big advantage of this scheme is that, in contrast to the original scheme, it does not require a computationally expensive function for mapping messages to primes. We prove this new scheme secure under adaptive chosen message attacks. Second, we present a modification that allows to significantly increase efficiency when signing long messages. This construction uses collision-resistant hash functions as its basis. As a result, our improvements make the signature length independent of the message size. Our construction deviates from the standard hash-and-sign approach in which the hash value of the message is signed in place of the message itself. We show that in the case of twin signatures, one can exploit the properties of the hash function as an integral part of the signature scheme. This improvement can be applied to both the SRSA based and SDH based twin signature scheme.

  14. Examination of the Relationship between Oral Health and Arterial Sclerosis without Genetic Confounding through the Study of Older Japanese Twins

    PubMed Central

    Kurushima, Yuko; Ikebe, Kazunori; Matsuda, Ken-ichi; Enoki, Kaori; Ogata, Soshiro; Yamashita, Motozo; Murakami, Shinya; Maeda, Yoshinobu

    2015-01-01

    Objective Although researchers have recently demonstrated a relationship between oral health and arterial sclerosis, the genetic contribution to this relationship has been ignored even though genetic factors are expected to have some effect on various diseases. The aim of this study was to evaluate oral health as a significant risk factor related to arterial sclerosis after eliminating genetic confounding through study of older Japanese twins. Subjects and Methods Medical and dental surveys were conducted individually for 106 Japanese twin pairs over the age of 50 years. Maximal carotid intima-media thickness (IMT-Cmax) was measured as a surrogate marker of arterial sclerosis. IMT-Cmax > 1.0 mm was diagnosed as arterial sclerosis. All of the twins were examined for the number of remaining teeth, masticatory performance, and periodontal status. We evaluated each measurement related with IMT-Cmax and arterial sclerosis using generalized estimating equations analysis adjusted for potential risk factors. For non-smoking monozygotic twins, a regression analysis using a “between within” model was conducted to evaluate the relationship between IMT-Cmax and the number of teeth as the environmental factor controlling genetic and familial confounding. Results We examined 91 monozygotic and 15 dizygotic twin pairs (males: 42, females: 64) with a mean (± standard deviation) age of 67.4 ± 10.0 years. Out of all of the oral health-related measurements collected, only the number of teeth was significantly related to arterial sclerosis (odds ratio: 0.72, 95% confidence interval: 0.52-0.99 per five teeth). Regression analysis showed a significant association between the IMT-Cmax and the number of teeth as an environmental factor (p = 0.037). Conclusions Analysis of monozygotic twins older than 50 years of age showed that having fewer teeth could be a significant environmental factor related to arterial sclerosis, even after controlling for genetic and familial confounding

  15. The relationship between anxiety disorders and dimensional representations of DSM-IV personality disorders: A co-twin control study

    PubMed Central

    Welander-Vatn, A.; Ystrom, E.; Tambs, K.; Neale, MC.; Kendler, KS.; Reichborn-Kjennerud, T.; Knudsen, GP.

    2015-01-01

    Background There is substantial comorbidity between personality disorders (PDs) and anxiety disorders (ADs). Sharing of familial risk factors possibly explains the co-occurrence, but direct causal relationships between the disorders may also exist. Methods 2801 persons from 1391 twin pairs from the Norwegian Institute of Public Health Twin Panel were assessed for all DSM-IV PDs and ADs. Bivariate Poisson-regression analyses were performed to assess whether PDs predicted ADs at three different levels: All PDs combined, PDs combined within DSM-IV-clusters and each individual PD separately. Next, bivariate co-twin control analyses were executed within monozygotic (MZ) and dizygotic (DZ) twin pairs. A similar analytic strategy was employed in multivariate models including PDs as independent variables. Results PDs predicted ADs at all levels of analysis in bivariate regression models. Bivariate co-twin control analyses demonstrated an increased risk of ADs in all PDs combined, all PD-clusters and in schizotypal, paranoid, borderline, antisocial, avoidant and dependent PD. In the multivariate regression model, all PD-clusters and schizotypal, borderline, avoidant and obsessive-compulsive PD predicted ADs. Only borderline and avoidant PD predicted ADs in the multivariate co-twin control analysis. Limitations Over-adjustment may explain the results from the multivariate analyses. The cross-sectional study design hampers causal inference. Conclusions Comorbidity between ADs and PDs can be largely accounted for by shared familial risk factors. However, the results are also consistent with a direct causal relationship partly explaining the co-occurrence. Our results indicate specific environmental factors for comorbidity of ADs and borderline and avoidant PDs that are not shared with other PDs. PMID:26544619

  16. Heritability of Biomarkers of Oxidized Lipoproteins: A Twin Pair Study

    PubMed Central

    Rao, Fangwen; Schork, Andrew J.; Maihofer, Adam X.; Nievergelt, Caroline M.; Marcovina, Santica; Miller, Elizabeth R.; Witztum, Joseph L.; O'Connor, Daniel T.; Tsimikas, Sotirios

    2015-01-01

    Objective To determine if biomarkers of oxidized lipoproteins are genetically determined. Lipoprotein(a) [Lp(a)] is a heritable risk factor and carrier of oxidized phospholipids (OxPL). Approach and Results We measured OxPL-apoB, Lp(a), IgG and IgM autoantibodies to malondialdehyde-modified low density lipoprotein (MDA-LDL), copper oxidized LDL (CuOxLDL) and apoB-immune complexes (ApoB-IC) in 386 monozygotic and dizygotic twins to estimate trait heritability (h2) and determine specific genetic effects among traits. A genome wide linkage study followed by genetic association was performed. The h2 (scale:0-1) for Lp(a) was 0.91±0.01 and for OxPL-apoB 0.87±0.02, which were higher than physiologic, inflammatory, or lipid traits. h2 of IgM MDA-LDL, CuOxLDL and ApoB-IC were 0.69±0.04, 0.67±0.05, and 0.80±0.03, respectively, and for IgG MDA-LDL, CuOxLDL and apoB-IC 0.62±0.05, 0.52±0.06, and 0.53±0.06, respectively. There was an inverse correlation between the major apo(a) isoform and OxPL-apoB (R=-0.49, p<0.001), and Lp(a) (R=-0.48, p<0.001) and OxPL-apoB was modestly correlated with Lp(a) (ρ=0.57, p<0.0001). The correlation in major apo(a) isoform size was concordant (R=1.0, p<0.001) among monozygotic twins but not dizygotic twins (R=0.40, p=0.055). Lp(a) and OxPL-apoB shared genetic co-determination (genetic covariance: ρG = 0.774±0.032, p=1.09×10-38), though not environmental determination (environmental covariance: ρE= 0.081±0.15, p=0.15). In contrast, Lp(a) shared environmental but not genetic co-determination with autoantibodies to MDA-LDL and CuOxLDL and ApoB-IC. Sib-pair genetic linkage of the Lp(a) trait revealed that SNP rs10455872 was significantly associated with OxPL-apoB after adjusting for Lp(a). Conclusions OxPL-apoB and other biomarkers of oxidized lipoproteins are highly heritable cardiovascular risk factors that suggest novel genetic origins of atherothrombosis. PMID:25953646

  17. Twinning and Multiple Birth Rates According to Maternal Age in the City of São Paulo, Brazil: 2003-2014.

    PubMed

    Otta, Emma; Fernandes, Eloisa de S; Acquaviva, Tiziana G; Lucci, Tania K; Kiehl, Leda C; Varella, Marco A C; Segal, Nancy L; Valentova, Jaroslava V

    2016-12-01

    The present study investigates the twinning rates in the city of São Paulo, Brazil, during the years 2003-2014. The data were drawn from the Brazilian Health Department database of Sistema de Informações de Nascidos Vivos de São Paulo-SINASC (Live Births Information System of São Paulo). In general, more information is available on the incidence of twinning in developed countries than in developing ones. A total of 24,589 twin deliveries and 736 multiple deliveries were registered in 140 hospitals of São Paulo out of a total of 2,056,016 deliveries during the studied time period. The overall average rates of singleton, twin, and multiple births per 1,000 maternities (‰) were 987.43, 11.96 (dizygotic (DZ) rate was 7.15 and monozygotic (MZ) 4.42), and 0.36, respectively. We further regressed maternal age and historical time period on percentage of singleton, twin, and multiple birth rates. Our results indicated that maternal age strongly positively predicted twin and multiple birth rates, and negatively predicted singleton birth rates. The historical time period also positively, although weakly, predicted twin birth rates, and had no effect on singleton or multiple birth rates. Further, after applying Weinberg's differential method, we computed regressions separately for the estimated frequencies of DZ and MZ twin rates. DZ twinning was strongly positively predicted by maternal age and, to a smaller degree, by time period, while MZ twinning increased marginally only with higher maternal age. Factors such as increasing body mass index or air pollution can lead to the slight historical increase in DZ twinning rates. Importantly, consistent with previous cross-cultural and historical research, our results support the existence of an age-dependent physiological mechanism that leads to a strong increase in twinning and multiple births, but not singleton births, among mothers of higher age categories. From the ultimate perspective, twinning and multiple births in

  18. Dental anxiety in relation to neuroticism and pain sensitivity. A twin study.

    PubMed

    Vassend, Olav; Røysamb, Espen; Nielsen, Christopher S

    2011-03-01

    Predisposing personality traits as well as heightened pain sensitivity and fear of pain have been hypothesized as central factors in the development of dental anxiety. The aim of the study was to estimate the heritability of dental anxiety, and to investigate the genetic and environmental sources of covariance between dental anxiety on one hand, and pain sensitivity and the neuroticism trait on the other. A sample comprising 188 twins, aged 23-35 years (53 monozygotic and 39 dizygotic twin pairs, and 4 single twins whose co-twin did not participate), was included in the study. Measures of dental anxiety and personality were obtained using Corah's Dental Anxiety Scale and the NEO Personality Inventory Revised, respectively. Heat pain and cold pressor pain sensitivity were assessed using standard pain testing procedures. Bivariate Cholesky models were employed to decompose the correlations between phenotypes into genetic and environmental factors. Using models with common additive genetic (A) and individual-specific environmental (E) factors, moderate heritability (i.e., .41) for dental anxiety was demonstrated. Virtually all of the phenotypic correlation between neuroticism and dental anxiety could be accounted for by A. Furthermore, a substantial part of the variance in dental anxiety was due to specific genetic and individual environmental influences unrelated to neuroticism. The phenotypic correlations between dental anxiety and the pain sensitivity indices were close to zero. Thus, while neuroticism and dental anxiety share a sizeable proportion of genetic (but not environmental) risk factors, the results also suggest that these two attributes are distinct entities with overlapping, but not identical, etiologies.

  19. Aging Trajectories in Different Body Systems Share Common Environmental Etiology: The Healthy Aging Twin Study (HATS).

    PubMed

    Moayyeri, Alireza; Hart, Deborah J; Snieder, Harold; Hammond, Christopher J; Spector, Timothy D; Steves, Claire J

    2016-02-01

    Little is known about the extent to which aging trajectories of different body systems share common sources of variance. We here present a large twin study investigating the trajectories of change in five systems: cardiovascular, respiratory, skeletal, morphometric, and metabolic. Longitudinal clinical data were collected on 3,508 female twins in the TwinsUK registry (complete pairs:740 monozygotic (MZ), 986 dizygotic (DZ), mean age at entry 48.9 ± 10.4, range 18-75 years; mean follow-up 10.2 ± 2.8 years, range 4-17.8 years). Panel data on multiple age-related variables were used to estimate biological ages for each individual at each time point, in linear mixed effects models. A weighted average approach was used to combine variables within predefined body system groups. Aging trajectories for each system in each individual were then constructed using linear modeling. Multivariate structural equation modeling of these aging trajectories showed low genetic effects (heritability), ranging from 2% in metabolic aging to 22% in cardiovascular aging. However, we found a significant effect of shared environmental factors on the variations in aging trajectories in cardiovascular (54%), skeletal (34%), morphometric (53%), and metabolic systems (53%). The remainder was due to environmental factors unique to each individual plus error. Multivariate Cholesky decomposition showed that among aging trajectories for various body systems there were significant and substantial correlations between the unique environmental latent factors as well as shared environmental factors. However, there was no evidence for a single common factor for aging. This study, the first of its kind in aging, suggests that diverse organ systems share non-genetic sources of variance for aging trajectories. Confirmatory studies are needed using population-based twin cohorts and alternative methods of handling missing data.

  20. Pan-genome of the dominant human gut-associated archaeon, Methanobrevibacter smithii, studied in twins.

    PubMed

    Hansen, Elizabeth E; Lozupone, Catherine A; Rey, Federico E; Wu, Meng; Guruge, Janaki L; Narra, Aneesha; Goodfellow, Jonathan; Zaneveld, Jesse R; McDonald, Daniel T; Goodrich, Julia A; Heath, Andrew C; Knight, Rob; Gordon, Jeffrey I

    2011-03-15

    The human gut microbiota harbors three main groups of H(2)-consuming microbes: methanogens including the dominant archaeon, Methanobrevibacter smithii, a polyphyletic group of acetogens, and sulfate-reducing bacteria. Defining their roles in the gut is important for understanding how hydrogen metabolism affects the efficiency of fermentation of dietary components. We quantified methanogens in fecal samples from 40 healthy adult female monozygotic (MZ) and 28 dizygotic (DZ) twin pairs, analyzed bacterial 16S rRNA datasets generated from their fecal samples to identify taxa that co-occur with methanogens, sequenced the genomes of 20 M. smithii strains isolated from families of MZ and DZ twins, and performed RNA-Seq of a subset of strains to identify their responses to varied formate concentrations. The concordance rate for methanogen carriage was significantly higher for MZ versus DZ twin pairs. Co-occurrence analysis revealed 22 bacterial species-level taxa positively correlated with methanogens: all but two were members of the Clostridiales, with several being, or related to, known hydrogen-producing and -consuming bacteria. The M. smithii pan-genome contains 987 genes conserved in all strains, and 1,860 variably represented genes. Strains from MZ and DZ twin pairs had a similar degree of shared genes and SNPs, and were significantly more similar than strains isolated from mothers or members of other families. The 101 adhesin-like proteins (ALPs) in the pan-genome (45 ± 6 per strain) exhibit strain-specific differences in expression and responsiveness to formate. We hypothesize that M. smithii strains use their different repertoires of ALPs to create diversity in their metabolic niches, by allowing them to establish syntrophic relationships with bacterial partners with differing metabolic capabilities and patterns of co-occurrence.

  1. Genetic and Environmental Contributions to Facial Morphological Variation: A 3D Population-Based Twin Study

    PubMed Central

    Djordjevic, Jelena; Zhurov, Alexei I.; Richmond, Stephen

    2016-01-01

    Introduction Facial phenotype is influenced by genes and environment; however, little is known about their relative contributions to normal facial morphology. The aim of this study was to assess the relative genetic and environmental contributions to facial morphological variation using a three-dimensional (3D) population-based approach and the classical twin study design. Materials and Methods 3D facial images of 1380 female twins from the TwinsUK Registry database were used. All faces were landmarked, by manually placing 37 landmark points, and Procrustes registered. Three groups of traits were extracted and analysed: 19 principal components (uPC) and 23 principal components (sPC), derived from the unscaled and scaled landmark configurations respectively, and 1275 linear distances measured between 51 landmarks (37 manually identified and 14 automatically calculated). The intraclass correlation coefficients, rMZ and rDZ, broad-sense heritability (h2), common (c2) and unique (e2) environment contributions were calculated for all traits for the monozygotic (MZ) and dizygotic (DZ) twins. Results Heritability of 13 uPC and 17 sPC reached statistical significance, with h2 ranging from 38.8% to 78.5% in the former and 30.5% to 84.8% in the latter group. Also, 1222 distances showed evidence of genetic control. Common environment contributed to one PC in both groups and 53 linear distances (4.3%). Unique environment contributed to 17 uPC and 20 sPC and 1245 distances. Conclusions Genetic factors can explain more than 70% of the phenotypic facial variation in facial size, nose (width, prominence and height), lips prominence and inter-ocular distance. A few traits have shown potential dominant genetic influence: the prominence and height of the nose, the lower lip prominence in relation to the chin and upper lip philtrum length. Environmental contribution to facial variation seems to be the greatest for the mandibular ramus height and horizontal facial asymmetry. PMID

  2. 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.

  3. Acardiac twin: an unusual case report.

    PubMed

    Kariappa, T M; Chidananda, H T; Mamatha, R

    2007-10-01

    Acardiac twinning is a rare anomaly .75% of cases occurring in monzygotic triplet pregnancies and the rest in monozygotic twins. We report an antenatally undiagnosed case of acardius amorphous. The condition results from abnormal placental vascular anastomoses termed as twin reversed arterial perfusion (TRAP) theory. Early sonographic prenatal diagnosis improves the survival of the normal twin called the pump twin.

  4. Heritability of Autism Spectrum Disorder in a UK Population-Based Twin Sample

    PubMed Central

    Colvert, Emma; Tick, Beata; McEwen, Fiona; Stewart, Catherine; Curran, Sarah R.; Woodhouse, Emma; Gillan, Nicola; Hallett, Victoria; Lietz, Stephanie; Garnett, Tracy; Ronald, Angelica; Plomin, Robert; Rijsdijk, Frühling; Happé, Francesca; Bolton, Patrick

    2016-01-01

    IMPORTANCE Most evidence to date highlights the importance of genetic influences on the liability to autism and related traits. However, most of these findings are derived from clinically ascertained samples, possibly missing individuals with subtler manifestations, and obtained estimates may not be representative of the population. OBJECTIVES To establish the relative contributions of genetic and environmental factors in liability to autism spectrum disorder (ASD) and a broader autism phenotype in a large population-based twin sample and to ascertain the genetic/environmental relationship between dimensional trait measures and categorical diagnostic constructs of ASD. DESIGN, SETTING, AND PARTICIPANTS We used data from the population-based cohort Twins Early Development Study, which included all twin pairs born in England and Wales from January 1, 1994, through December 31, 1996. We performed joint continuous-ordinal liability threshold model fitting using the full information maximum likelihood method to estimate genetic and environmental parameters of covariance. Twin pairs underwent the following assessments: the Childhood Autism Spectrum Test (CAST) (6423 pairs; mean age, 7.9 years), the Development and Well-being Assessment (DAWBA) (359 pairs; mean age, 10.3 years), the Autism Diagnostic Observation Schedule (ADOS) (203 pairs; mean age, 13.2 years), the Autism Diagnostic Interview–Revised (ADI-R) (205 pairs; mean age, 13.2 years), and a best-estimate diagnosis (207 pairs). MAIN OUTCOMES AND MEASURES Participants underwent screening using a population-based measure of autistic traits (CAST assessment), structured diagnostic assessments (DAWBA, ADI-R, and ADOS), and a best-estimate diagnosis. RESULTS On all ASD measures, correlations among monozygotic twins (range, 0.77-0.99) were significantly higher than those for dizygotic twins (range, 0.22-0.65), giving heritability estimates of 56% to 95%. The covariance of CAST and ASD diagnostic status (DAWBA, ADOS

  5. Covariance structure of neuroticism and agreeableness: a twin and molecular genetic analysis of the role of the serotonin transporter gene.

    PubMed

    Jang, K L; Hu, S; Livesley, W J; Angleitner, A; Riemann, R; Ando, J; Ono, Y; Vernon, P A; Hamer, D H

    2001-08-01

    The Revised NEO Personality Inventory domains of Neuroticism and Agreeableness are considered factorially distinct despite several intercorrelations between these domains. The genetic correlation, an index of the degree to which these intercorrelations are caused by genetic influences, was estimated using data from 913 monozygotic and 562 dizygotic volunteer twin pairs from Canada, Germany, and Japan. The serotonin transporter gene, 5-HTTLPR, was assayed in a sample of 388 nontwin sibling pairs from the United States to determine the contribution of the serotonin transporter locus to the covariation between the Neuroticism and Agreeableness scales. In all four samples, genetic influences contributed to the covariance of Neuroticism and Agreeableness, with the serotonin transporter gene accounting for 10% of the relationship between these domains.

  6. Nutrition in twin pregnancy.

    PubMed

    MacGillivray, I

    1979-01-01

    The urinary nitrogen output appears to be related to both protein and energy intake, so that women having heavier babies probably eat more, although this may simply mean that they are larger women. Women with twin pregnancies have been found to have a lesser urinary nitrogen output, but it seems unlikely that this be due to lower intakes. They might simply utilize their diet more efficiently--a hypothesis that is now being tested.

  7. Challenges of Twin Pregnancy

    PubMed Central

    Wilson, Lynn M.; Hose, Patricia M.

    1991-01-01

    Family physicians have an important role in the diagnosis and management of twin pregnancies. Optimal antepartum management begins with early detection. Provision of patient education about the risks of the pregnancy is important. Intrapartum management is dependent on gestation age, placentation, fetal presentation, and fetal well-being. Anticipatory guidance and ongoing support should be provided for postpartum issues, such as breast-feeding and family adjustment. PMID:21229108

  8. Sleep Duration and Area-Level Deprivation in Twins

    PubMed Central

    Watson, Nathaniel F.; Horn, Erin; Duncan, Glen E.; Buchwald, Dedra; Vitiello, Michael V.; Turkheimer, Eric

    2016-01-01

    Study Objectives: We used quantitative genetic models to assess whether area-level deprivation as indicated by the Singh Index predicts shorter sleep duration and modifies its underlying genetic and environmental contributions. Methods: Participants were 4,218 adult twin pairs (2,377 monozygotic and 1,841 dizygotic) from the University of Washington Twin Registry. Participants self-reported habitual sleep duration. The Singh Index was determined by linking geocoding addresses to 17 indicators at the census-tract level using data from Census of Washington State and Census Tract Cartographic Boundary Files from 2000 and 2010. Data were analyzed using univariate and bivariate genetic decomposition and quantitative genetic interaction models that assessed A (additive genetics), C (common environment), and E (unique environment) main effects of the Singh Index on sleep duration and allowed the magnitude of residual ACE variance components in sleep duration to vary with the Index. Results: The sample had a mean age of 38.2 y (standard deviation [SD] = 18), and was predominantly female (62%) and Caucasian (91%). Mean sleep duration was 7.38 h (SD = 1.20) and the mean Singh Index score was 0.00 (SD = 0.89). The heritability of sleep duration was 39% and the Singh Index was 12%. The uncontrolled phenotypic regression of sleep duration on the Singh Index showed a significant negative relationship between area-level deprivation and sleep length (b = −0.080, P < 0.001). Every 1 SD in Singh Index was associated with a ∼4.5 min change in sleep duration. For the quasi-causal bivariate model, there was a significant main effect of E (b0E = −0.063; standard error [SE] = 0.30; P < 0.05). Residual variance components unique to sleep duration were significant for both A (b0Au = 0.734; SE = 0.020; P < 0.001) and E (b0Eu = 0.934; SE = 0.013; P < 0.001). Conclusions: Area-level deprivation has a quasi-causal association with sleep duration, with greater deprivation being related to

  9. 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.

  10. Characterization of melanocyte stimulating hormone receptor variant alleles in twins with red hair.

    PubMed

    Box, N F; Wyeth, J R; O'Gorman, L E; Martin, N G; Sturm, R A

    1997-10-01

    The association between MSHR coding region variation and hair colour in humans has been examined by genotyping 25 red haired and 62 non-red Caucasians, all of whom were 12 years of age and members of a twin pair study. Twelve amino acid substitutions were seen at 11 different sites, nine of these being newly described MSHR variants. The previously reported Val92Met allele shows no association with hair colour, but the three alleles Arg151Cys, Arg160Trp and Asp294His were associated with red hair and one Val60Leu variant was most frequent in fair/blonde and light brown hair colours. Variant MSHR genotypes are associated with lighter skin types and red hair (P < 0.001). However, comparison of the MSHR genotypes in dizygotic twin pairs discordant for red hair colour indicates that the MSHR gene cannot be solely responsible for the red hair phenotype, since five of 13 pairs tested had both haplotypes identical by state (with three of the five having both identical by descent). Rather, it is likely that additional modifier genes exist, making variance in the MSHR gene necessary but not always sufficient, for red hair production.

  11. Quantitative variability of 342 plasma proteins in a human twin population

    PubMed Central

    Liu, Yansheng; Buil, Alfonso; Collins, Ben C; Gillet, Ludovic CJ; Blum, Lorenz C; Cheng, Lin-Yang; Vitek, Olga; Mouritsen, Jeppe; Lachance, Genevieve; Spector, Tim D; Dermitzakis, Emmanouil T; Aebersold, Ruedi

    2015-01-01

    The degree and the origins of quantitative variability of most human plasma proteins are largely unknown. Because the twin study design provides a natural opportunity to estimate the relative contribution of heritability and environment to different traits in human population, we applied here the highly accurate and reproducible SWATH mass spectrometry technique to quantify 1,904 peptides defining 342 unique plasma proteins in 232 plasma samples collected longitudinally from pairs of monozygotic and dizygotic twins at intervals of 2–7 years, and proportioned the observed total quantitative variability to its root causes, genes, and environmental and longitudinal factors. The data indicate that different proteins show vastly different patterns of abundance variability among humans and that genetic control and longitudinal variation affect protein levels and biological processes to different degrees. The data further strongly suggest that the plasma concentrations of clinical biomarkers need to be calibrated against genetic and temporal factors. Moreover, we identified 13 cis-SNPs significantly influencing the level of specific plasma proteins. These results therefore have immediate implications for the effective design of blood-based biomarker studies. PMID:25652787

  12. The Genetic and Environmental Contributions to Internet Use and Associations With Psychopathology: A Twin Study.

    PubMed

    Long, Elizabeth C; Verhulst, Brad; Neale, Michael C; Lind, Penelope A; Hickie, Ian B; Martin, Nicholas G; Gillespie, Nathan A

    2016-02-01

    Excessive internet use has been linked to psychopathology. Therefore, understanding the genetic and environmental risks underpinning internet use and their relation to psychopathology is important. This study aims to explore the genetic and environmental etiology of internet use measures and their associations with internalizing disorders and substance use disorders. The sample included 2,059 monozygotic (MZ) and dizygotic (DZ) young adult twins from the Brisbane Longitudinal Twin Study (BLTS). Younger participants reported more frequent internet use, while women were more likely to use the internet for interpersonal communication. Familial aggregation in 'frequency of internet use' was entirely explained by additive genetic factors accounting for 41% of the variance. Familial aggregation in 'frequency of use after 11 pm', 'using the internet to contact peers', and 'using the internet primarily to access social networking sites' was attributable to varying combinations of additive genetic and shared environmental factors. In terms of psychopathology, there were no significant associations between internet use measures and major depression (MD), but there were positive significant associations between 'frequency of internet use' and 'frequency of use after 11 pm' with social phobia (SP). 'Using the internet to contact peers' was positively associated with alcohol abuse, whereas 'using the internet to contact peers' and 'using the internet primarily to access social networking sites' were negatively associated with cannabis use disorders and nicotine symptoms. Individual differences in internet use can be attributable to varying degrees of genetic and environmental risks. Despite some significant associations of small effect, variation in internet use appears mostly unrelated to psychopathology.

  13. Trojan twin planets

    NASA Astrophysics Data System (ADS)

    Dvorak, R.; Loibnegger, B.; Schwarz, R.

    2017-03-01

    The Trojan asteroids are moving in the vicinity of the stable Lagrange points L_4 and L_5 of the gas giants Jupiter, Uranus and Neptune. Their motion can be described and understood with the aid of the restricted three-body problem. As an extension of this problem we investigate how stable motion close to the Lagrange points of two massive bodies can exist. This configuration can be described as the Trojan Twin Problem when we regard the two additional bodies as having a mass significantly smaller than the the two primary bodies: a star in the center (m_1) and an additional Jupiter-like mass (m_2). Using this 4-body problem we have undertaken numerical investigations concerning possible stable "twin orbits". However, these two bodies (m_3 and m_4) in Trojan-like orbits may have quite different masses. We decided to choose 6 different scenaria for this problem: as primary body, m2, we have taken a Jupiter-like planet, a Saturn-like one, and a super-Earth with 10 Earthmasses (m_{Earth}) respectively. As quasi twin planets, we have used different mass ratios namely objects for m3 and m4 from 10m_{Earth} to Moon like ones. We found different stable configurations depending on the involved masses and the initial distances between the twins (always close to the Lagrange point). Although the formation of such a configuration seems to be not very probable we should not exclude that it exists regarding the huge number of planets even in our own galaxy. This model is of special interest when the most massive planet (m_2) is moving on an orbit in the habitable zone around a main sequence star. One can use our results of stable orbits of Trojan Twin Planets (or asteroids) for extrasolar systems having as second primary a Jupiter-like, a Saturn-like or a super-Earth like planet around a star similar to our Sun.

  14. A study of the birth weight-obesity relation using a longitudinal cohort and sibling and twin pairs.

    PubMed

    The, Natalie S; Adair, Linda S; Gordon-Larsen, Penny

    2010-09-01

    Sibling and twin study designs provide control for confounding factors that are typically unmeasured in traditional cohort studies. Using nationally representative data from the National Longitudinal Study of Adolescent Health collected at 3 visits during 1994-2002, the authors evaluated the longitudinal association between birth weight and later obesity in a traditional cohort study (n = 13,763; ages 11-21 years at baseline), controlling for sex, age, race/ethnicity, and parental education. Among persons with a nonobese mother, high birth weight (>4 kg) participants were more likely than normal birth weight (>/=2.5-twins: n = 207; dizygotic twins: n = 189), the authors examined longitudinal within-pair differences. Birth weight difference was positively associated with body mass index difference later in life for female monozygotic pairs only (beta = 2.67, 95% confidence interval: 0.99, 4.35). Given the null associations observed in the sibling sample, the commonly observed positive association between birth weight and later obesity from cohort analyses may be attributed to confounding by maternal characteristics. Further research is needed to identify specific factors that contribute to the birth weight-obesity relation.

  15. Correlation and heritability in neuroimaging datasets: a spatial decomposition approach with application to an fMRI study of twins.

    PubMed

    Park, Joonkoo; Shedden, Kerby; Polk, Thad A

    2012-01-16

    Advances in modern neuroimaging in combination with behavioral genetics have allowed neuroscientists to investigate how genetic and environmental factors shape human brain structure and function. Estimating the heritability of brain structure and function via twin studies has become one of the major approaches in studying the genetics of the brain. In a classical twin study, heritability is estimated by computing genetic and phenotypic variation based on the similarity of monozygotic and dizygotic twins. However, heritability has traditionally been measured for univariate, scalar traits, and it is challenging to assess the heritability of a spatial process, such as a pattern of neural activity. In this work, we develop a statistical method to estimate phenotypic variance and covariance at each location in a spatial process, which in turn can be used to estimate the heritability of a spatial dataset. The method is based on a dimensionally-reduced model of spatial variation in paired images, in which adjusted least squares estimates can be used to estimate the key model parameters. The advantage of the proposed method compared to conventional methods such as voxelwise or mean-ROI approaches is demonstrated in both a simulation study and a real data study assessing genetic influence on patterns of brain activity in the visual and motor cortices in response to a simple visuomotor task.

  16. Genetic regulation of growth from birth to 18 years of age: the Swedish young male twins study.

    PubMed

    Silventoinen, Karri; Pietiläinen, Kirsi H; Tynelius, Per; Sørensen, Thorkild I A; Kaprio, Jaakko; Rasmussen, Finn

    2008-01-01

    Growth is a complex process, and only little is known on the genetic regulation of it. We analyzed the effect of genetic and environmental factors on growth in a longitudinal Swedish cohort of 231 monozygotic and 144 dizygotic twin pairs born 1973-1979 with length or height measured annually from birth to age 18. The data were analyzed by two different multivariate variance component models for twin data using the Mx statistical package. At birth and 1 year of age, a substantial part of the variation in length was because of common environment (50 and 57%, respectively) and the effect of genetic factors was minor. After 2 years of age, 91-97% of the variation of height could be explained by genetic differences whereas the rest was because of environmental variation not shared by twins. The genetic correlation between heights at ages 2 and 18 was 0.73 (95% confidence intervals 0.68-0.77) showing that 53% of the genes affecting height at these ages are the same or closely linked; with increasing age the correlation with genetic effects at age 18 become subsequently stronger. Especially in mid-childhood, growth was largely regulated by the same genetic factors. During puberty new genetic factors started to affect height, but also genetic variation affecting height at previous ages remained. These results suggest that genetic regulation of growth is rather uniform, which is encouraging for further efforts to identify genes affecting growth.

  17. [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.

  18. Monozygotic twins discordant for sex.

    PubMed Central

    Schmidt, R; Sobel, E H; Nitowsky, H M; Dar, H; Allen, F H

    1976-01-01

    A pair of monozygotic, adolescent twins is discordant for sex. The phenotypic female twin has chromosome constitution of 46, XY/45, X. She displays many signs of Turner's syndrome, including typical facies, webbed neck, malformed left kidney, high plasma gonadotropins, and streak ovaries. However, her height is 154 cm which exceeds the height usually reported in Turner's syndrome. The male twin has a karyotype of 46, XY and normal sexual development. Only two other reports of pairs of monozygotic twins of opposite sex have been published. Images PMID:944787

  19. When You Are a Twin or Triplet

    MedlinePlus

    ... be a twin? Are you a twin and wonder why everyone thinks it's so special? It's fascinating ... the way the egg is fertilized when a woman becomes pregnant . In fraternal twins, two different eggs ...

  20. Genetic and environmental influences on cross-gender behavior and relation to behavior problems: a study of Dutch twins at ages 7 and 10 years.

    PubMed

    van Beijsterveldt, C E M; Hudziak, James J; Boomsma, Dorret I

    2006-12-01

    The aim of this study was to investigate the prevalence of cross-gender behavior during childhood, to estimate the influence of genotype and environment on variation in cross-gender behavior, and to explore the association of cross-gender behavior with maternal ratings of behavior problems as indexed by the Internalizing and Externalizing scales of the Child Behavior Checklist (CBCL). Cross-gender behavior was assessed by two items from the CBCL: "behaves like opposite sex" and "wishes to be of opposite sex." As part of an ongoing longitudinal study of the Netherlands Twin Registry, mothers were asked to complete the CBCL for their twins when they were 7 (n approximately 14,000 twins) and 10 years old (n approximately 8,500 twins). The prevalence of cross-gender behavior (as measured by maternal report of behaving like or wishing to be the opposite sex) was 3.2% and 5.2% for 7-year-old boys and girls, respectively, and decreased to 2.4% and 3.3% for 10-year-old boys and girls. Surprisingly, the prevalence rate of cross-gender behavior of girls with a male co-twin was lower than of girls with a female co-twin. At both ages, the similarity for cross-gender behavior was greater in monozygotic than in dizygotic twins pairs. Genetic structural equation modeling showed that 70% of the variance in the liability of cross-gender behavior could be explained by genetic factors, at both ages and for both sexes. Cross-gender behavior was associated with higher scores on Internalizing and Externalizing problems, both in boys and in girls.

  1. Temperament and Character in the Child and Adolescent Twin Study in Sweden (CATSS): Comparison to the General Population, and Genetic Structure Analysis

    PubMed Central

    Garcia, Danilo; Lundström, Sebastian; Brändström, Sven; Råstam, Maria; Cloninger, C. Robert; Kerekes, Nóra; Nilsson, Thomas; Anckarsäter, Henrik

    2013-01-01

    Background The Child and Adolescent Twin Study in Sweden (CATSS) is an on-going, large population-based longitudinal twin study. We aimed (1) to investigate the reliability of two different versions (125-items and 238-items) of Cloninger's Temperament and Character Inventory (TCI) used in the CATSS and the validity of extracting the short version from the long version, (2) to compare these personality dimensions between twins and adolescents from the general population, and (3) to investigate the genetic structure of Cloninger's model. Method Reliability and correlation analyses were conducted for both TCI versions, 2,714 CATSS-twins were compared to 631 adolescents from the general population, and the genetic structure was investigated through univariate genetic analyses, using a model-fitting approach with structural equation-modeling techniques based on same-sex twin pairs from the CATSS (423 monozygotic and 408 dizygotic pairs). Results The TCI scores from the short and long versions showed comparable reliability coefficients and were strongly correlated. Twins scored about half a standard deviation higher in the character scales. Three of the four temperament dimensions (Novelty Seeking, Harm Avoidance, and Persistence) had strong genetic and non-shared environmental effects, while Reward Dependence and the three character dimensions had moderate genetic effects, and both shared and non-shared environmental effects. Conclusions Twins showed higher scores in character dimensions compared to adolescents from the general population. At least among adolescents there is a shared environmental influence for all of the character dimensions, but only for one of the temperament dimensions (i.e., Reward Dependence). This specific finding regarding the existence of shared environmental factors behind the character dimensions in adolescence, together with earlier findings showing a small shared environmental effects on character among young adults and no shared

  2. Twin Legacies: Victor and Vincent McKusick/Twin Studies: Twinning Rates I; Twinning Rates II; MZ Twin Discordance for Russell-Silver Syndrome; Twins' Language Skills/Headlines: Babies Born to Identical Twin Couples; Identity Exchange; Death of Princess Ashraf (Twin); Yahoo CEO Delivers Identical Twins.

    PubMed

    Segal, Nancy L

    2016-04-01

    The lives of the illustrious monozygotic (MZ) twins, Victor A. and Vincent L. McKusick, are described. Victor earned the distinction as the 'Father of Medical Genetics', while Vincent was a legendary Chief Justice of the Maine Supreme Court. This dual biographical account is followed by two timely reports of twinning rates, a study of MZ twin discordance for Russell-Silver Syndrome (RSS) and a study of twins' language skills. Twin stories in the news include babies born to identical twin couples, a case of switched identity, the death of Princess Ashraf (Twin) and a new mother of twins who is also Yahoo's CEO.

  3. Health-Related Findings Among Twin Pairs Discordant for Leisure-Time Physical Activity for 32 Years: The TWINACTIVE Study Synopsis.

    PubMed

    Leskinen, Tuija; Kujala, Urho M

    2015-06-01

    We are lacking very long-term and controlled intervention studies investigating the effects of habitual physical activity on health-related factors. To address this gap, we performed a natural experiment by identifying same-sex twin pairs in which the co-twins of each pair differed with respect to leisure-time physical-activity habits throughout their adult life. Our criterion for the discordance was that the same co-twin had a higher leisure time-activity volume than that of the other member of the pair at the majority -- if not all -- of the follow-up time points according to reported/interviewed physical-activity data. Overall, we identified and conducted multidimensional health-related measurements (including fitness, body composition, cardiometabolic risk factor levels, bone and arterial status, and exercise motivation) of 16 twin pairs (seven monozygotic (MZ) and nine dizygotic (DZ) pairs, mean age 60 years) who had persistent discordance in leisure-time physical-activity habits over three decades (TWINACTIVE study). In our discordant-pair study design, after adjusting for sequence-level genes, both systemic-level metabolic, and site-specific structural findings differed significantly in the pairwise analysis in MZ pairs only. These findings included intrapair differences in accumulated fat depots and structure of heart, arteries, and bones. In addition, our study revealed intrapair differences in metabolic and regulatory pathways, which may partly explain the mechanistic links between long-term physical activity, phenotypic changes, and decreased risk of cardiometabolic diseases.

  4. A healthy delivery of twins by assisted reproduction followed by preimplantation genetic screening in a woman with X-linked dominant incontinentia pigmenti

    PubMed Central

    Kim, Myung Joo; Lyu, Sang Woo; Seok, Hyun Ha; Park, Ji Eun

    2014-01-01

    The purpose of this study is to report a successful twin pregnancy and delivery in a female patient with X-linked dominant incontinentia pigmenti (IP) who underwent assisted reproductive technology followed by preimplantation genetic screening (PGS). A 29-year-old female with IP had a previous history of recurrent spontaneous abortion. A molecular analysis revealed the patient had a de novo mutation, 1308_1309insCCCCTTG(p.Ala438ProfsTer26), in the inhibitor of the kappa B kinase gamma gene located in the Xq28 region. IVF/ICSI and PGS was performed, in which male embryos were sexed using array-based comparative genomic hybridization (aCGH). After IVF/ICSI and PGS using aCGH on seven embryos, two euploid male blastocysts were transferred with a 50% probability of a viable male pregnancy. The dizygotic twin pregnancy was confirmed and the amniocentesis results of each twin were normal with regard to the mutation found in the mother. The patient delivered healthy twin babies during the 37th week of gestation. This case shows the beneficial role of PGS in achieving a successful pregnancy through euploid male embryo gender selection in a woman with X-linked dominant IP with a history of multiple male miscarriages. PMID:25599040

  5. Twin Peaks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. 3D glasses are necessary to identify surface detail. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.

    The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  6. Transformation: From Twin to Individual

    ERIC Educational Resources Information Center

    Magagna, Jeanne

    2007-01-01

    This article explores some of the complexities of psychotherapy with an identical twin. The difficulty of developing in psychotherapy while so much of what is oneself is located in the other twin will also be explored. The use of the countertransference as a therapeutic method will be considered as the young person develops her unique, separate…

  7. [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.

  8. Gut DNA viromes of Malawian twins discordant for severe acute malnutrition.

    PubMed

    Reyes, Alejandro; Blanton, Laura V; Cao, Song; Zhao, Guoyan; Manary, Mark; Trehan, Indi; Smith, Michelle I; Wang, David; Virgin, Herbert W; Rohwer, Forest; Gordon, Jeffrey I

    2015-09-22

    The bacterial component of the human gut microbiota undergoes a definable program of postnatal development. Evidence is accumulating that this program is disrupted in children with severe acute malnutrition (SAM) and that their persistent gut microbiota immaturity, which is not durably repaired with current ready-to-use therapeutic food (RUTF) interventions, is causally related to disease pathogenesis. To further characterize gut microbial community development in healthy versus malnourished infants/children, we performed a time-series metagenomic study of DNA isolated from virus-like particles (VLPs) recovered from fecal samples collected during the first 30 mo of postnatal life from eight pairs of mono- and dizygotic Malawian twins concordant for healthy growth and 12 twin pairs discordant for SAM. Both members of discordant pairs were sampled just before, during, and after treatment with a peanut-based RUTF. Using Random Forests and a dataset of 17,676 viral contigs assembled from shotgun sequencing reads of VLP DNAs, we identified viruses that distinguish different stages in the assembly of the gut microbiota in the concordant healthy twin pairs. This developmental program is impaired in both members of SAM discordant pairs and not repaired with RUTF. Phage plus members of the Anelloviridae and Circoviridae families of eukaryotic viruses discriminate discordant from concordant healthy pairs. These results disclose that apparently healthy cotwins in discordant pairs have viromes associated with, although not necessarily mediators, of SAM; as such, they provide a human model for delineating normal versus perturbed postnatal acquisition and retention of the gut microbiota's viral component in populations at risk for malnutrition.

  9. Gut DNA viromes of Malawian twins discordant for severe acute malnutrition

    PubMed Central

    Reyes, Alejandro; Blanton, Laura V.; Cao, Song; Zhao, Guoyan; Manary, Mark; Trehan, Indi; Smith, Michelle I.; Wang, David; Virgin, Herbert W.; Rohwer, Forest; Gordon, Jeffrey I.

    2015-01-01

    The bacterial component of the human gut microbiota undergoes a definable program of postnatal development. Evidence is accumulating that this program is disrupted in children with severe acute malnutrition (SAM) and that their persistent gut microbiota immaturity, which is not durably repaired with current ready-to-use therapeutic food (RUTF) interventions, is causally related to disease pathogenesis. To further characterize gut microbial community development in healthy versus malnourished infants/children, we performed a time-series metagenomic study of DNA isolated from virus-like particles (VLPs) recovered from fecal samples collected during the first 30 mo of postnatal life from eight pairs of mono- and dizygotic Malawian twins concordant for healthy growth and 12 twin pairs discordant for SAM. Both members of discordant pairs were sampled just before, during, and after treatment with a peanut-based RUTF. Using Random Forests and a dataset of 17,676 viral contigs assembled from shotgun sequencing reads of VLP DNAs, we identified viruses that distinguish different stages in the assembly of the gut microbiota in the concordant healthy twin pairs. This developmental program is impaired in both members of SAM discordant pairs and not repaired with RUTF. Phage plus members of the Anelloviridae and Circoviridae families of eukaryotic viruses discriminate discordant from concordant healthy pairs. These results disclose that apparently healthy cotwins in discordant pairs have viromes associated with, although not necessarily mediators, of SAM; as such, they provide a human model for delineating normal versus perturbed postnatal acquisition and retention of the gut microbiota’s viral component in populations at risk for malnutrition. PMID:26351661

  10. Genetic influences on brain asymmetry: a DTI study of 374 twins and siblings.

    PubMed

    Jahanshad, Neda; Lee, Agatha D; Barysheva, Marina; McMahon, Katie L; de Zubicaray, Greig I; Martin, Nicholas G; Wright, Margaret J; Toga, Arthur W; Thompson, Paul M

    2010-08-15

    Brain asymmetry, or the structural and functional specialization of each brain hemisphere, has fascinated neuroscientists for over a century. Even so, genetic and environmental factors that influence brain asymmetry are largely unknown. Diffusion tensor imaging (DTI) now allows asymmetry to be studied at a microscopic scale by examining differences in fiber characteristics across hemispheres rather than differences in structure shapes and volumes. Here we analyzed 4Tesla DTI scans from 374 healthy adults, including 60 monozygotic twin pairs, 45 same-sex dizygotic pairs, and 164 mixed-sex DZ twins and their siblings; mean age: 24.4years+/-1.9 SD). All DTI scans were nonlinearly aligned to a geometrically-symmetric, population-based image template. We computed voxel-wise maps of significant asymmetries (left/right differences) for common diffusion measures that reflect fiber integrity (fractional and geodesic anisotropy; FA, GA and mean diffusivity, MD). In quantitative genetic models computed from all same-sex twin pairs (N=210 subjects), genetic factors accounted for 33% of the variance in asymmetry for the inferior fronto-occipital fasciculus, 37% for the anterior thalamic radiation, and 20% for the forceps major and uncinate fasciculus (all L>R). Shared environmental factors accounted for around 15% of the variance in asymmetry for the cortico-spinal tract (R>L) and about 10% for the forceps minor (L>R). Sex differences in asymmetry (men>women) were significant, and were greatest in regions with prominent FA asymmetries. These maps identify heritable DTI-derived features, and may empower genome-wide searches for genetic polymorphisms that influence brain asymmetry.

  11. 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…

  12. The Genetic Relationship between Indentical Twins.

    ERIC Educational Resources Information Center

    Herman, Rosemary

    1984-01-01

    Reviews current research on a woman's chances of bearing twins and the genetic relationship, prenatal competition, and personality similarities between twins. In addition, the nature/nurture controversy is discussed in terms of evidence from studies of identical twins reared apart. Future studies are suggested to discover the ways twinning might…

  13. Recipient twin limb ischemia with postnatal onset.

    PubMed

    Broadbent, Roland Spencer

    2007-02-01

    After the occurrence of 3 local cases of limb ischemia in newborn twins, we reviewed the literature to investigate this combination systematically. This review reveals a distinct condition: postnatal onset limb ischemia affecting recipient twins in twin-twin transfusion syndrome.

  14. Best Practices for Twin Placement in School

    ERIC Educational Resources Information Center

    Lacina, Jan

    2012-01-01

    The children's book "Two Is for Twins" celebrates twins and illustrates the many "twos" in a child's world. The uniqueness of twos does not have to mean separate classrooms for twins in child development programs, preschool, or elementary school settings. With recent dramatic increases in the US twin population, how should educators address the…

  15. 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.

  16. Centenary Celebration for Scottish Missionary Mary Slessor: A Lasting Legacy for Twins/Twin Research: Twins With Kleinfelter's Syndrome; Twin Research on Atopic Diseases; Twin Study of Autism; Psychotherapy with Twins / General Interest: Female Twin Pole-Vaulters; Longest Twin Birth Interval; Pair of Franco-Cuban Vocalists; Croatian Twin Models.

    PubMed

    Segal, Nancy L

    2015-06-01

    The centenary celebration for Scottish missionary, Mary Slessor, took place on February 14, 2015 in Melle, Belgium. Slessor saved many newborn twins and their mothers from death and disownment by members of their community, including their families, who believed twins harbored evil spirits. The events of this unusual and significant gathering are described. Next, twin research and reports concerning Kleinfelter's disease, atopic diseases, autism and psychotherapy are presented. General interest subjects include identical female twin pole-vaulters, the longest twin birth interval, Franco-Cuban twin vocalists, and Croatian twin models.

  17. The vector-like twin Higgs

    SciTech Connect

    Craig, Nathaniel; Knapen, Simon; Longhi, Pietro; Strassler, Matthew

    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.

  18. Failure of vincristine induce twinning

    NASA Technical Reports Server (NTRS)

    Binder, M.

    1984-01-01

    Mammalian ova do not contain axes of symmetry from which are derived embryonic axes of symmetry. Mammalian axis determination is an early embryologic event occurring at about the time that monozygous twinning in mice. (Kaufma MH & O'Shea KS, 1978, Nature 276:707) and an attempt was made to reproduce their work in several strains of mice. Over 3200 embryos were examined without any twins being found. To rule out the possibility that vincristine caused twinning plus some lethal malformation (with subsequent resorption of the embryo) the embryos were examined 36-60 hours after vincristine treatment.

  19. Mechanism of slip and twinning

    NASA Technical Reports Server (NTRS)

    Rastani, Mansur

    1992-01-01

    The objectives are to: (1) demonstrate the mechanisms of deformation in body centered cubic (BCC), face centered cubic (FCC), and hexagonal close-packed (HCP)-structure metals and alloys and in some ceramics as well; (2) examine the deformed microstructures (slip lines and twin boundaries) in different grains of metallic and ceramic specimens; and (3) study visually the deformed macrostructure (slip and twin bands) of metals and alloys. Some of the topics covered include: deformation behavior of materials, mechanisms of plastic deformation, slip bands, twin bands, ductile failure, intergranular fracture, shear failure, slip planes, crystal deformation, and dislocations in ceramics.

  20. Special forms in twin pregnancy - asymmetric conjoined twins.

    PubMed

    Anca, F A; Negru, A; Mihart, A E; Grigoriu, C; Bohîlțea, R E

    2015-01-01

    Twin pregnancies generally represent a high-risk pregnancy. However, monozygous twins are real challenges for obstetricians due to the complications that may occur. Among the particular cases of monozygous twins in the University Emergency Hospital of Bucharest, Department of Obstetrics and Gynecology, a monochorial monoamniotic pregnancy with conjoined twins has been described. These particular medical circumstances require a deeper understanding of the vascular anatomical particularities. An accurate diagnosis implies a most detailed description of the morphological dynamics of the fetuses with the study of the impact of the vascular anomaly on their development so that the maximum chances of survival and the best outcome for the viable fetus can be obtained. The diagnosis of the most frequently associated anomalies is also extremely important.

  1. Microscopic Particles in Two Fractions of Fresh Cerebrospinal Fluid in Twins with Schizophrenia or Bipolar Disorder and in Healthy Controls

    PubMed Central

    Johansson, Viktoria; Nybom, Rolf; Wetterberg, Lennart; Hultman, Christina M.; Cannon, Tyrone D.; Johansson, Anette G. M.; Ekman, Carl Johan; Landén, Mikael

    2012-01-01

    Background Using scanning electron microscopy, microscopic structures have been identified in fresh cerebrospinal fluid (CSF) in patients with schizophrenia and bipolar disorder, but only rarely in control subjects. However, it has not been determined whether these microscopic particles represent state or trait markers, i.e. if their presence is related to clinical manifestations of the disease or if they also can be found in as yet asymptomatic individuals with a genetic liability. This question can be addressed by studying twins discordant or concordant for schizophrenia or bipolar disorder. Methodology/Principal Findings We investigated microscopic structures in CSF in 102 individuals: 21 monozygotic and 16 dizygotic twins affected or not affected with schizophrenia, schizoaffective disorder or bipolar disorder and in 65 healthy singleton controls. A first and a second fraction of CSF was freshly applied on filters and examined by scanning electron microscopy technique. Spherical particles with lipid appearance averaging between 0.1 to 8.0 µm in diameter were detected in the center of the filter as well as located in the margins of larger aggregates binding in a viscous state. Structures were found in 12 of 17 probands, 5 of 12 healthy co-twins and 3 of 73 healthy controls. Thus, a positive microscopic finding significantly increased the likelihood of belonging to the proband group (OR = 48, 95% CL: 8.2–550, p<0.0001) and the co-twin-group (OR = 16, 95% CL: 2.0–218, p = 0.006). Age, sex, history of alcohol abuse or anxiety syndrome, somatic disorder and markers of acute inflammatory activity did not account for group differences; nor did exposure to psychotropic medication. Conclusion Presence of microscopic particles in CSF may possibly reflect trait dependent genetic or environmental vulnerability in patients with schizophrenia, schizoaffective disorder or bipolar disorder. PMID:23049916

  2. A twin study of genetic and environmental determinants of abnormal persistence of psychotic experiences in young adulthood.

    PubMed

    Wigman, Johanna T W; van Winkel, Ruud; Jacobs, Nele; Wichers, Marieke; Derom, Catherine; Thiery, Evert; Vollebergh, Wilma A M; van Os, Jim

    2011-07-01

    Evidence suggests that subclinical psychotic experiences are more likely to cause transition to psychotic disorder if their expression becomes persistent. The study of longitudinal patterns of subclinical psychotic experiences may help to distinguish subgroups with transient and persistent psychotic symptoms, who may differ in risk of later psychosis. The current study investigated patterns of developmental course of subclinical psychotic experiences in a general population sample of 566 female twins, aged 18-45 years. The positive symptoms subscale of the Community Assessment of Psychic Experiences (CAPE), completed three times in 2 years, was analyzed with growth modeling. Using Latent Class Analysis, two developmental courses were distinguished: a Persistent and a Low (expression of subclinical psychotic experiences) group. The Persistent group reported significantly higher levels of depressive and negative symptoms and worse functioning in daily life. Childhood trauma (OR: 3.26, P < 0.0001) and stressful life events over the study period (OR: 3.15, P = 0.031) predicted membership of the Persistent group. Of the monozygotic (MZ) twins with their co-twin in the Persistent group, 49% also were in the Persistent group themselves (OR: 9.32, P < 0.0001), compared to only 14% in the dizygotic (DZ) co-twins (OR: 1.56, P = 0.42) (χ(2)(2) = 22.97; P < 0.001). The findings suggest that persistence of subclinical psychosis is influenced by both genetic and environmental factors, providing the possibility to study the (possibly modifiable) etiology underlying the longitudinal process of persistence of the early expression of psychosis liability.

  3. Isolated oligodontia in monozygotic twins

    PubMed Central

    Halicioglu, Koray; Sahin, Hakan; Corekci, Bayram; Irgin, Celal; Toptas, Orcun

    2013-01-01

    This case report defines a case of isolated oligodontia of 9 and 10 permanent teeth in 9-year-old monozygotic twin sisters and gives information about the possible genetic and environmental etiology, related dental anomalies and treatment options. The twins have a negative family history of hypodontia and oligodontia in their parents, as well as their paternal and maternal grandmothers and first cousins. No other dental anomalies could be detected in either of the twins. With the occurrence of similarly located tooth agenesis, except for one tooth, in monozygotic twins, one may consider the influence of genetic and/or environmental factors in their etiology. Hereditary relationships associated with oligodontia could help the clinicians to predict the possibility of its occurrence in other family members and in the next generations. However, clinicians should consider oligodontia when it is not hereditary. PMID:24966717

  4. Twins, Triplets, and Other Multiples

    MedlinePlus

    ... complications Pregnancy loss Know your pregnancy rights Getting ready for baby Childbirth and ... Twins, triplets, and other multiples If you are pregnant with more than one baby, you are far from alone. In the ...

  5. Twin-Axial Wire Antenna

    DTIC Science & Technology

    2015-08-06

    08-2015 Publication Twin-Axial Wire Antenna David A. Tonn Naval Under Warfare Center Division, Newport 1176 Howell St., Code 00L, Bldg 102T...Approved for Public Release Distribution is unlimited Attorney Docket No. 300030 1 of 10 TWIN-AXIAL WIRE ANTENNA STATEMENT OF GOVERNMENT INTEREST...2 of 10 length of the antenna wire . This creates a high pass filter in the antenna and prevents current flow in the VLF/LF bands. [0005] U.S

  6. A novel mutation affecting the arginine-137 residue of AVPR2 in dizygous twins leads to nephrogenic diabetes insipidus and attenuated urine exosome aquaporin-2.

    PubMed

    Hinrichs, Gitte R; Hansen, Louise H; Nielsen, Maria R; Fagerberg, Christina; Dieperink, Hans; Rittig, Søren; Jensen, Boye L

    2016-04-01

    Mutations in the vasopressin V2 receptor gene AVPR2 may cause X-linked nephrogenic diabetes insipidus by defective apical insertion of aquaporin-2 in the renal collecting duct principal cell. Substitution mutations with exchange of arginine at codon 137 can cause nephrogenic syndrome of inappropriate antidiuresis or congenital X-linked nephrogenic diabetes insipidus. We present a novel mutation in codon 137 within AVPR2 with substitution of glycine for arginine in male dizygotic twins. Nephrogenic diabetes insipidus was demonstrated by water deprivation test and resistance to vasopressin administration. While a similar urine exosome release rate was shown between probands and controls by western blotting for the marker ALIX, there was a selective decrease in exosome aquaporin-2 versus aquaporin-1 protein in probands compared to controls.

  7. Evolution des syndromes électrocliniques chez des jumeaux dizygotes: de l'enfance à l'adolescence, à propos d'une observation

    PubMed Central

    Bugeme, Marcellin; Kadiebwe, David Mulumba; Kakoma, Placide Kambola; Mukuku, Olivier

    2015-01-01

    Les syndromes électrocliniques ont une prédisposition génétique très variable et leur évolution de l'enfance vers l'adolescence ou l’âge adulte n'est pas bien définie. Nous rapportons ici une observation mettant en jeu deux jumeaux dizygotes âgés de 19 ans ayant présenté un phénotype épileptique différent pendant l'enfance (épilepsie avec absences myocloniques et épilepsie-absence de l'enfant) mais une concordance phénotypique (épilepsie à crises généralisées tonico-cloniques prédominantes) au cours de l'adolescence. Cette observation plaide en faveur d'une implication génétique dans l’évolution de ces syndromes électrocliniques. PMID:26090006

  8. A general method to determine twinning elements

    PubMed Central

    Zhang, Yudong; Li, Zongbin; Esling, Claude; Muller, Jacques; Zhao, Xiang; Zuo, Liang

    2010-01-01

    The fundamental theory of crystal twinning has been long established, leading to a significant advance in understanding the nature of this physical phenomenon. However, there remains a substantial gap between the elaborate theory and the practical determination of twinning elements. This paper proposes a direct and simple method – valid for any crystal structure and based on the minimum shear criterion – to calculate various twinning elements from the experimentally determined twinning plane for Type I twins or the twinning direction for Type II twins. Without additional efforts, it is generally applicable to identify and predict possible twinning modes occurring in a variety of crystalline solids. Therefore, the present method is a promising tool to characterize twinning elements, especially for those materials with complex crystal structure. PMID:22477779

  9. Genetic and environmental covariations among obsessive-compulsive symptoms, neuroticism, and extraversion in South Korean adolescent and young adult twins.

    PubMed

    Hur, Yoon-Mi

    2009-04-01

    A growing literature suggests that personality traits may be endophenotype markers for psychiatric illnesses. Although the phenotypic relationships between obsessive-compulsive disorder (OCD) and high neuroticism and low extraversion have been well documented, underlying genetic and environmental contributions to these associations have not been explored previously. Five hundred and twenty-four monozygoitc (MZ) and 228 dizygotic (DZ) pairs of adolescent and young adult twins (aged 13-24 years) drawn from the South Korean Twin Registry completed the Maudsley Obsessive Compulsive Inventory (MOCI) and the Neuroticism and Extraversion scale of the Eysenck Personality Scale by mail. The total score of MOCI (MOCIT) was significantly and positively correlated with Neuroticism (r = .44), but only weakly and negatively related to Extraversion (r = -.10). A trivariate Cholesky model was applied to the data. The additive genetic correlations in the best-fitting model were .51 between Neuroticism and MOCIT and -.17 between Extraversion and MOCIT, suggesting that additive genetic factors that lead to high neuroticism and low extraversion overlap with those genetic factors influencing high OC symptoms. These findings add to the cumulative evidence of the shared genetic etiology for the associations between a personality profile of high neuroticism and low extraversion and mental illnesses.

  10. Sepsis in preterm infants causes alterations in mucosal gene expression and microbiota profiles compared to non-septic twins

    PubMed Central

    Cernada, María; Bäuerl, Christine; Serna, Eva; Collado, Maria Carmen; Martínez, Gaspar Pérez; Vento, Máximo

    2016-01-01

    Sepsis is a life-threatening condition in preterm infants. Neonatal microbiota plays a pivotal role in the immune system maturation. Changes in gut microbiota have been associated to inflammatory disorders; however, a link with sepsis in the neonatal period has not yet been established. We aimed to analyze gut microbiota and mucosal gene expression using non-invasively obtained samples to provide with an integrative perspective of host-microbe interactions in neonatal sepsis. For this purpose, a prospective observational case-control study was conducted in septic preterm dizygotic twins and their non-septic twin controls. Fecal samples were used for both microbiota analysis and host genome-wide expression using exfoliated intestinal cells. Gene expression of exfoliated intestinal cells in septic preterm showed an induction of inflammatory and oxidative stress pathways in the gut and pro-oxidant profile that caused dysbiosis in the gut microbiota with predominance of Enterobacteria and reduction of Bacteroides and Bifidobacterium spp.in fecal samples, leading to a global reduction of beneficial anaerobic bacteria. Sepsis in preterm infants induced low-grade inflammation and oxidative stress in the gut mucosa, and also changes in the gut microbiota. This study highlights the role of inflammation and oxidative stress in neonatal sepsis on gut microbial profiles. PMID:27180802

  11. The Twin Jet Nebula

    NASA Technical Reports Server (NTRS)

    1997-01-01

    M2-9 is a striking example of a 'butterfly' or a bipolar planetary nebula. Another more revealing name might be the 'Twin Jet Nebula.' If the nebula is sliced across the star, each side of it appears much like a pair of exhausts from jet engines. Indeed, because of the nebula's shape and the measured velocity of the gas, in excess of 200 miles per second, astronomers believe that the description as a super-super-sonic jet exhaust is quite apt. This is much the same process that takes place in a jet engine: The burning and expanding gases are deflected by the engine walls through a nozzle to form long, collimated jets of hot air at high speeds. M2-9 is 2,100 light-years away in the constellation Ophiucus. The observation was taken Aug. 2, 1997 by the Hubble telescope's Wide Field and Planetary Camera 2. In this image, neutral oxygen is shown in red, once-ionized nitrogen in green, and twice-ionized oxygen in blue.

  12. Twin Dimples Intrigue Scientists

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image from the Mars Exploration Rover Opportunity is part of the first set of pictures that was returned to Earth after the rover exited 'Eagle Crater.' Scientists are busy analyzing Opportunity's new view of the plains of Meridiani Planum. The plentiful ripples are a clear indication that wind is the primary geologic process currently in effect on the plains. On the left of the image are two depressions--each about a meter (about 3.3 feet) across--that feature bright spots in their centers. One possibility is that the bright material is similar in composition to the rocks in Eagle Crater's outcrop and the surrounding darker material is what's referred to as 'lag deposit,' or erosional remnants that are much harder and more difficult to wear away. These twin dimples might be revealing pieces of a larger outcrop that lies beneath. The depression closest to Opportunity is whimsically referred to as 'Homeplate' and the one behind it as 'First Base.' The rover's panoramic camera is set to take detailed images of the depressions today, on Opportunity's 58th sol. The backshell and parachute that helped protect the rover and deliver it safely to the surface of Mars are also visible near the horizon, in the center of the image. This image was taken by the rover's navigation camera.

  13. Estimating twin concordance for bivariate competing risks twin data.

    PubMed

    Scheike, Thomas H; Holst, Klaus K; Hjelmborg, Jacob B

    2014-03-30

    For twin time-to-event data, we consider different concordance probabilities, such as the casewise concordance that are routinely computed as a measure of the lifetime dependence/correlation for specific diseases. The concordance probability here is the probability that both twins have experienced the event of interest. Under the assumption that both twins are censored at the same time, we show how to estimate this probability in the presence of right censoring, and as a consequence, we can then estimate the casewise twin concordance. In addition, we can model the magnitude of within pair dependence over time, and covariates may be further influential on the marginal risk and dependence structure. We establish the estimators large sample properties and suggest various tests, for example, for inferring familial influence. The method is demonstrated and motivated by specific twin data on cancer events with the competing risk death. We thus aim to quantify the degree of dependence through the casewise concordance function and show a significant genetic component.

  14. Genetic and environmental etiology of emotional and social behaviors in 5-month-old infant twins: influence of the social context.

    PubMed

    Soussignan, Robert; Boivin, Michel; Girard, Alain; Pérusse, Daniel; Liu, Xuecheng; Tremblay, Richard E

    2009-01-01

    The study investigated the genetic and environmental contributions to individual differences in measures of socioemotional reactivity and emotion regulation with a sample of 115 monozygotic (MZ) and 156 dizygotic (DZ) 5-month-old twin pairs. Twins' zygosity was determined by a combination of DNA typing and physical similarity. Twins' behaviors (motor activity level, social gaze, gaze aversion, positive expression, negative expression, and self-comfort) were videotaped in a laboratory while infants were presented televised sequences of neutral and happy emotional expressions posed by their mother (familiar condition) and a female stranger (unfamiliar condition). Regardless of the social context, the findings based on model-fitting analyses indicated that nonshared environmental influences explained most of the variance of behavioral data. However, there was evidence that motor activity level (an index of emotional arousal) and the latency and frequency of gaze aversion (an index of emotional regulation) were best represented by a model incorporating both additive genetic and nonshared environmental (i.e., AE) influences when infants were exposed to the unfamiliar adult (heritability estimates ranging from 19% to 31%). The results suggest the importance of nonshared environmental influences during early infancy and stress the role of social context for revealing moderate genetic contributions to individual differences in emotional arousal and emotion regulation.

  15. Brain Derived Neurotrophic Factor (BDNF) levels as a possible predictor of psychopathology in healthy twins at high and low risk for affective disorder.

    PubMed

    Vinberg, Maj; Miskowiak, Kamilla; Kessing, Lars Vedel

    2014-01-01

    Brain Derived Neurotrophic Factor (BDNF) is a potential biomarker of affective disorder. However, longitudinal studies evaluating a potential predictive role of BDNF on subsequent psychopathology are lacking. The aim of this study was to investigate whether BDNF alone or in interaction with the BDNF Val66Met polymorphism predict onset of affective disorder in healthy individuals at heritable risk for affective disorder. In a high-risk study, we assessed whole blood levels of BDNF in 234 healthy monozygotic and dizygotic twins with or without a co-twin history of affective disorder (high and low risk twins, respectively). Participants were followed up longitudinally with questionnaires at 6-month intervals for mean seven years and then reassessed with a personal interview to obtain information about whether they had developed psychiatric illness. At follow-up 36 participants (15.4%) had developed psychiatric disorder. Cox regression analysis revealed that BDNF levels at baseline were not associated with onset of illness in this explorative study. Further, two-way interactions between BDNF levels and the Val66Met polymorphism or between familial risk and the Val66Met polymorphism did not predict illness onset.

  16. Vasospastic Angina in Identical Twins

    PubMed Central

    Yoshioka, Takayuki; Otsui, Kazunori; Suzuki, Atsushi; Ozawa, Toru; Iwata, Sachiyo; Takei, Asumi; Inoue, Nobutaka

    2015-01-01

    Patient: Male, 58 Final Diagnosis: Vasospastic angina Symptoms: Chest pain Medication: — Clinical Procedure: Medical treatment Specialty: Cardiology Objective: Rare disease Background: The clinical conditions of various diseases, including coronary artery disease, are determined by genetics and the environment. Previous investigations noted the significance of genetic mutations and polymorphisms in cases of coronary spasm. Case Report: We report on monozygotic identical twins who almost simultaneously presented with vasospastic angina. The 58-year-old younger twin was admitted to our hospital because of persistent chest pain. An electrocardiogram showed an inverted T wave in the left precordial leads. Coronary angiographies revealed a short left main trunk (LMT) and 50% stenosis at the proximal portion of the left anterior descending artery (LAD). Infusion of acetylcholine to his left coronary artery caused marked vasoconstriction associated with a sensation of chest oppression. Nitroglycerine completely reversed this response. Based on these findings, we diagnosed Twin A with vasospastic angina. At nearly the same time, his identical twin brother was diagnosed with vasospastic angina at another hospital. Comparison of both coronary angiograms indicated similar structure of coronary vessels, including short LMT and mild stenosis at the proximal portion of LAD. Conclusions: These 2 cases highlight the importance of genetic factors in the pathogenesis of vasospastic angina. It may be important for individuals to receive medical attention if their identical twin presents with vasospastic angina. PMID:26347942

  17. Breastfeeding, maternal education and cognitive function: a prospective study in twins.

    PubMed

    Bartels, M; van Beijsterveldt, C E M; Boomsma, D I

    2009-11-01

    The effect of breastfeeding on cognitive abilities is examined in the offspring of highly educated women and compared to the effects in women with low or middle educational attainment. All offspring consisted of 12-year old mono- or dizygotic twins and this made it possible to study the effect of breastfeeding on mean cognition scores as well as the moderating effects of breastfeeding on the heritability of variation in cognition. Information on breastfeeding and cognitive ability was available for 6,569 children. Breastfeeding status was prospectively assessed in the first years after birth of the children. Maternal education is positively associated with performance on a standardized test for cognitive ability in offspring. A significant effect of breastfeeding on cognition was also observed. The effect was similar for offspring with mothers with a high, middle, and low educational level. Breast-fed children of highly educated mothers score on average 7.6 point higher on a standardized test of cognitive abilities (CITO test; range 500–550; effects size = .936) than formula-fed children of mothers with a low education. Individual differences in cognition scores are largely accounted for by additive genetic factors (80%) and breastfeeding does not modify the effect of genetic factors in any of the three strata of maternal education. Heritability was slightly lower in children with a mother with a middle-level education.

  18. Mapping cis- and trans-regulatory effects across multiple tissues in twins

    PubMed Central

    Grundberg, Elin; Small, Kerrin S.; Hedman, Åsa K.; Nica, Alexandra C.; Buil, Alfonso; Keildson, Sarah; Bell, Jordana T.; Yang, Tsun-Po; Meduri, Eshwar; Barrett, Amy; Nisbett, James; Sekowska, Magdalena; Wilk, Alicja; Shin, So-Youn; Glass, Daniel; Travers, Mary; Min, Josine L.; Ring, Sue; Ho, Karen; Thorleifsson, Gudmar; Kong, Augustine; Thorsteindottir, Unnur; Ainali, Chrysanthi; Dimas, Antigone S.; Hassanali, Neelam; Ingle, Catherine; Knowles, David; Krestyaninova, Maria; Lowe, Christopher E.; Di Meglio, Paola; Montgomery, Stephen B.; Parts, Leopold; Potter, Simon; Surdulescu, Gabriela; Tsaprouni, Loukia; Tsoka, Sophia; Bataille, Veronique; Durbin, Richard; Nestle, Frank O.; O’Rahilly, Stephen; Soranzo, Nicole; Lindgren, Cecilia M.; Zondervan, Krina T.; Ahmadi, Kourosh R.; Schadt, Eric E.; Stefansson, Kari; Smith, George Davey; McCarthy, Mark I.; Deloukas, Panos; Dermitzakis, Emmanouil T.; Spector, Tim D.

    2013-01-01

    Sequence-based variation in gene expression is a key driver of disease risk. Common variants regulating expression in cis have been mapped in many eQTL studies typically in single tissues from unrelated individuals. Here, we present a comprehensive analysis of gene expression across multiple tissues conducted in a large set of mono- and dizygotic twins that allows systematic dissection of genetic (cis and trans) and non-genetic effects on gene expression. Using identity-by-descent estimates, we show that at least 40% of the total heritable cis-effect on expression cannot be accounted for by common cis-variants, a finding which exposes the contribution of low frequency and rare regulatory variants with respect to both transcriptional regulation and complex trait susceptibility. We show that a substantial proportion of gene expression heritability is trans to the structural gene and identify several replicating trans-variants which act predominantly in a tissue-restricted manner and may regulate the transcription of many genes. PMID:22941192

  19. 180. Photocopy of Photograph, Twin Falls Canal Company. E. Pettygro, ...

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

    180. Photocopy of Photograph, Twin Falls Canal Company. E. Pettygro, Photographer, date unknown. BLASTING TWIN FALLS CANAL, TWIN FALLS COUNTY; BLASTING COTTONWOOD AREA TO REPLACE FLUME BY RUNNING HIGH LINE THROUGH SOLID ROCK. - 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

  20. Impact of Twin-to-Twin Transfusion Syndrome, Preterm Birth, and Vision Loss on Development

    ERIC Educational Resources Information Center

    Celeste, Marie

    2005-01-01

    This study compared the developmental outcomes of twin boys (one who is blind and one who is sighted) who were born prematurely and diagnosed with twin-to-twin transfusion syndrome (TTTS) at age 24 months. The results indicate a disparity in the developmental outcomes of the twins. Although the medical risk factors that are associated with TTTS…

  1. Brief Report: Autistic Traits in Twins vs. Non-Twins--A Preliminary Study

    ERIC Educational Resources Information Center

    Ho, Alexander; Todd, Richard D.; Constantino, John N.

    2005-01-01

    Previous studies have suggested that among affected sib pairs with autism there is an increase in the frequency of twins over what would be expected in comparison to the prevalence of twins in the general population. In this study we sought to determine whether "sub-threshold" autistic traits were more pronounced in twins than in non-twins. The…

  2. Having Twins? How to Stay Healthy

    MedlinePlus

    ... Listen Español Text Size Email Print Share Having Twins? How to Stay Healthy Page Content Article Body ... the eyes of obstetricians. Many would call a twin pregnancy a high-risk pregnancy , but don’t ...

  3. Nike Twins Seven Seven: Nigerian Batik Artist.

    ERIC Educational Resources Information Center

    LaDuke, Betty

    1987-01-01

    Chronicles the personal and professional life of Nike Twins Seven Seven (born 1951), a Nigerian batik artist, and her husband, Twins Seven Seven, a musician-artist, both of whom have received international acclaim. (BJV)

  4. Twin seasonality in a rural Catalonian population.

    PubMed

    Hernández, Miquel; García-Moro, Clara; Toja, Domingo Isaac; Esparza, Mireia; González-José, Rolando

    2004-12-01

    The seasonality of twinning in the Spanish populations has not been studied until now. Differences between seasonal distribution of the twin conceptions and those of the single births have been observed in other populations. The aim of this work is to explore the frequency of twinning in a rural population from Catalonia during the nineteenth century, as well as the seasonality patterns characterizing each of the twinning types. Data corresponding to all births recorded at Tortosa (South Catalonia) from 1801 to 1900 have been analyzed in order to study the twinning distribution. The distribution of the moving averages of the monthly rates of twins shows a peak in autumn. Twinning distribution differs from the total births' distribution in Tortosa. This fact is very clear in the case of unlike-sexed twins that have their greater incidence in the last quarter of the year, while the total maternities have their peak in the first one.

  5. Evidence for genetic regulation of vitamin D status in twins with multiple sclerosis23

    PubMed Central

    Orton, Sarah-Michelle; Morris, Andrew P; Herrera, Blanca M; Ramagopalan, Sreeram V; Lincoln, Matthew R; Chao, Michael J; Vieth, Reinhold; Sadovnick, A Dessa; Ebers, George C

    2008-01-01

    Background: Multiple sclerosis (MS) risk is determined by both genes and environment. One of the most striking features of MS is its geographic distribution, particularly the pattern of high MS frequency in areas with low sunlight exposure, the main inducer of vitamin D synthesis. Recent epidemiologic, experimental, and clinical evidence support an effect for low environmental supplies of vitamin D in mediating an increased susceptibility to MS. Objectives: We 1) examined the association of serum 25-hydroxy-vitaminD [25(OH)D] concentrations and MS status and 2) assessed the genetic contribution to serum 25(OH)D concentrations and tested for its association with genetic variants in 2 candidate genes [vitamin D receptor and 1-α-hydroxylase (CYP27B1)]. Design: We used a twin study approach, comprising adult pairs identified from the longitudinal population-based Canadian Collaborative Project on Genetic Susceptibility to MS. Monozygotic (MZ; n = 40) and dizygotic (DZ; n = 59) pairs, both concordant and discordant for MS, were studied. End-of-winter serum 25(OH)D concentrations were measured by radioimmunoassay, and genotypes were assessed by single nucleotide polymorphism (SNP) assay. Results: Serum concentrations of 25(OH)D were highly correlated in MS-concordant pairs (r = 0.83, P < 0.001), but they were not significantly associated with having the disease (P = 0.4) when analyzed by logistic regression. Intraclass correlation for 25(OH)D concentration was significantly greater in MZ pairs (MZ, r: 0.71 > DZ r: 0.32, P = 0.006). Significant associations of 2 CYP27B1 SNP variants and 25(OH)D concentrations were observed. Conclusion: The findings indicate important genetic influences on regulation of seasonal circulating 25(OH)D concentrations in MS twins. PMID:18689381

  6. Genetic factors in evolution of sleep length--a longitudinal twin study in Finnish adults.

    PubMed

    Hublin, Christer; Partinen, Markku; Koskenvuo, Markku; Kaprio, Jaakko

    2013-10-01

    Genetic factors affect many aspects of sleep, such as sleep length. We investigated the contribution of genetic factors to stability and change of sleep length among adults over a 15-year period. In this representative follow-up study we used the Finnish Twin Cohort as the study population. Questionnaire surveys were performed in 1975 (response rate 89%, 11,041 twin pairs; age ≥18 years), 1981 (84%, 9323; ≥24 years) and 1990 (77%, 4507; 33-60 years). Sleep was categorized as short (<7 h), average or long (>8 h). Pairwise similarity in monozygotic and dizygotic pairs was examined at each survey by age group and sex. Quantitative genetic modelling was used to estimate cross-sectional and longitudinal genetic effects. The proportion of variance in sleep length at one point in time that was accounted for by genetic effects was very stable over the study period, being 0.31 in 1975, 0.32 in 1981 and 0.30 in 1990. Longitudinal genetic modelling indicated that the correlations of genetic effects between the three measurement points were high: 0.85 between 1975 and 1981; 0.93 between 1981 and 1990; and 0.76 between 1975 and 1990. Despite a high contribution of environmental effects, their correlations over time were modest: 0.31 between 1975 and 1981; 0.33 between 1981 and 1990; and 0.18 between 1975 and 1990. In conclusion, genetic factors have a modest but stable effect on the evolution of sleep length over a long time span in adults. Multiple measures are a more robust basis for genetic analyses than a single cross-sectional measure.

  7. 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.

  8. Twins' injuries: genetic and environmental risks / twin research reports / human interest stories.

    PubMed

    Segal, Nancy L

    2011-04-01

    The relative contributions of genetic and environmental factors to unintentional injuries are of interest to families with young twins. A recent study found that childhood injuries are explained mostly by child-specific environmental factors. Next, twin research reviews of the association between periodontal disease and cancer, secular trends in gestational age and birthweight, and language development in hearing and deaf co-twins are also summarized. Interesting reports of newborn twins, twin-like relationships, twin interactions and missed twin relationships are presented.

  9. Personality and intelligence: persistence, not self-directedness, cooperativeness or self-transcendence, is related to twins' cognitive abilities.

    PubMed

    Mousavi, Fariba; Rozsa, Sandor; Nilsson, Thomas; Archer, Trevor; Anckarsäter, Henrik; Garcia, Danilo

    2015-01-01

    Background. A person-centered approach focusing on the interaction of an individual's temperament-character-life events is essential in the path of individuals' well-being. In this context, three character traits, Self-directedness (e.g., self-acceptance, self-control, goal-directed behavior), Cooperativeness (e.g., social affiliation, social tolerance, empathy and helpfulness) and Self-transcendence (e.g., spiritual acceptance, transpersonal identification), measured using Cloninger's model of personality are suggested to help the individual to regulate and resolve the conflicts derived from her/his temperament combinations as a reaction to life events. However, if character is related to the individual's cognitive ability, then this association might limit any intervention that focuses on character development. We used data from the Child and Adolescent Twin Study in Sweden (CATSS) to investigate the relationship between personality and cognitive ability. Method. The sample consisted of 370 15-year-old twins (159 girls/211 boys), 192 of whom screen-positive with various types of mental health problems. We used the Temperament and Character Inventory to measure personality and the Wechsler Intelligence Scales for Children (WISC-IV) to measure intelligence. The relationship was investigated using correlation analyses using random-selected twins from each dyad and separately for monozygotic and dizygotic twins. Additional analyses investigated the genetic and environmental effects on personality and cognitive ability in this specific sample. Results. There were no significant correlations between the WISC-IV indices and any of the character traits (i.e., Self-directedness, Cooperativeness, and Self-transcendence). Persistence was significantly related, if weak, to four WISC-IV indices: Verbal Comprehension, Perceptual Reasoning, Working Memory, and the Full WISC-IV Scale. Post-hoc cross-twin/cross-trait analyses showed that the Persistence-cognitive ability

  10. [Pygopagus Siamese twins. Surgical treatment].

    PubMed

    Rollán Villamarín, V; Ollero Fresno, J C; Alonso Calderón, J L; Ollero Caprani, J M

    1991-04-01

    A case is presented wherein a set of black female pygopagus siamese twins were successfully separated by our department in their 45th day of life. Both twins had multiple malformations: cardiopulmonary, vertebral, anorectal, genitourinary, etc. The bilateral renal absence in one of them, originated her death on the 7th postoperative day. Only nine other cases have been referred successful during the last 35 years, in a bibliographic review conducted. The associated malformations and surgical skills for treatment and separation of them, are studied: previous colostomy and effective separation at life ages, comprised between one and thirteen months.

  11. The Twin Cities biomedical consortium.

    PubMed

    Bailey, A S

    1975-07-01

    Twenty-eight health science libraries in the St. Paul-Minneapolis area formed the Twin Cities Biomedical Consortium with the intention of developing a strong network of biomedical libraries in the Twin Cities area. Toward this end, programs were designed to strengthen lines of communication and increase cooperation among local health science libraries; improve access to biomedical information at the local level; and enable the Consortium, as a group, to meet an increasing proportion of its members' needs for biomedical information. Presently, the TCBC comprises libraries in twenty-two hospitals, two county medical societies, one school of nursing, one junior college, and two private corporations.

  12. On Teaching About Twins and Time

    ERIC Educational Resources Information Center

    Hewitt, Paul G.

    1973-01-01

    Discusses a four-step instructional presentation in which the twin on the earth is demonstrated older than the twin aboard a spaceship on the basis of the relativistic Doppler effect. Concludes that both twins can meet again at the same place in space at the expense of time. (CC)

  13. Natal Influences and Twin Differences: Draft.

    ERIC Educational Resources Information Center

    Van den Daele, Leland D.

    1972-01-01

    A classification of natal influences is proposed with a model of their operation. Natal influences affect maternal capacity, maternal load, and maternal efficiency. Since maternal load is increased in twin pregnancy, results of twin studies must be generalized with caution. The method of co-twin control is exemplified by examination of a small…

  14. [The diagnostic algorithm in twin pregnancy].

    PubMed

    Ropacka-Lesiak, Mariola; Szaflik, Krzysztof; Breborowicz, Grzegorz H

    2015-03-01

    This paper presents the diagnostic algorithm in twin pregnancy. The most important sonographic parameters in the assessment of twins have been discussed. Moreover, the most significant complications of twin pregnancy as well as diagnostic possibilities and management, have been also presented and defined.

  15. Multiple rectal carcinoid tumors in monozygotic twins.

    PubMed

    Doi, Momoko; Ikawa, Osamu; Taniguchi, Hiroki; Kawamura, Takuji; Katsura, Kanade

    2016-08-01

    We report multiple rectal carcinoid tumors in monozygotic twins who, respectively, had 42 and 36 carcinoid tumors in the lower rectum. This is the first report about carcinoid tumors in monozygotic twins. Both twins developed a similar number of rectal carcinoids with a similar distribution. Investigation of their genetic background may provide information about the origin of these tumors.

  16. Postpartum Mental State of Mothers of Twins

    ERIC Educational Resources Information Center

    Brantmüller, Éva; Gyúró, Mónika; Galgán, Kitti; Pakai, Annamária

    2016-01-01

    Twin birth is a relevant risk factor for postnatal depression (PND). The primary objective of our study is to reveal the prevalence of suspected cases of depression and to identify some background factors among mothers of twins. We applied convenience sampling method within a retrospective, quantitative study among mothers given birth to twins for…

  17. 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.

  18. Glide twinning and pseudotwinning in peristerite: twin morphology and propagation

    NASA Astrophysics Data System (ADS)

    Brown, William L.

    1989-07-01

    Optically visible Albite glide “twins” in a peristerite (˜An9Or1.6), identified from their tapering shape and relationship to grain boundaries, were studied by transmission electron microscopy. Near the tips in sections ⊥ a, the microstructure consists of small (˜400 nm long) lensshaped Albite twins centred exclusively on the oligoclase lamellae. The lenses extend partly outwards into the two adjacent low albite lamellae and induce strong inhomogeneous strain. Where the lenses are closer together, they form, depending on the sense of shear, nearly linear left or right-stepping en échelon arrays, with overlap of the strain fields. Slightly farther in from the tip, the twin domains coalesce to form continuous pinch-and-swell lamellae, being always thicker in the oligoclase. Because of Si,Al order, only elastic glide pseudotwins are possible in low albite. In oligoclase glide pseudotwins may be mechanically stable (metastable relative to Si,Al order) and may deviate only slightly from true twins. Pseudotwins develop first in the oligoclase, propagate dynamically by jumping across the intervening albite lamellae, extend lengthways and thicken sideways and finally coalesce. They are stabilized by diffusion-controlled inversion of Si,Al order giving rise to true twins described in a companion paper.

  19. Are stressful life events causally related to the severity of obsessive-compulsive symptoms? A monozygotic twin difference study

    PubMed Central

    Vidal-Ribas, P.; Stringaris, A.; Rück, C.; Serlachius, E.; Lichtenstein, P.; Mataix-Cols, D.

    2015-01-01

    Traumatic or stressful life events have long been hypothesized to play a role in causing or precipitating obsessive-compulsive symptoms but the impact of these environmental factors has rarely been investigated using genetically informative designs. We tested whether a wide range of retrospectively-reported stressful life events (SLEs) influence the lifetime presence and severity of obsessive-compulsive symptoms (OCS) in a large Swedish population-based cohort of 22,084 twins. Multiple regression models examined whether differences in SLEs within twin pairs were significantly associated with differences in OCS. In the entire sample (i.e., both monozygotic [MZ] and dizygotic twin pairs), two SLEs factors, “abuse and family disruption” and “sexual abuse”, were significantly associated with the severity of OCS even after controlling for depressive symptoms. Other SLEs factors were either not associated with OCS (“loss”, “non-sexual assault”) or were no longer associated with OCS after controlling for depression (“illness/injury”). Within MZ pair analyses, which effectively control for genetic and shared environmental effects, showed that only the “abuse and family disruption” factor remained independently related to within-pair differences in OCS severity, even after controlling for depressive symptoms. Despite being statistically significant, the magnitude of the associations was small; “abuse and family disruption” explained approximately 3% of the variance in OCS severity. We conclude that OCS are selectively associated with certain types of stressful life events. In particular, a history of interpersonal abuse, neglect and family disruption may make a modest but significant contribution to the severity of OCS. Further replication in longitudinal cohorts is essential before causality can be firmly established. PMID:25511316

  20. Conceptual and data-based investigation of genetic influences and brain asymmetry: a twin study of multiple structural phenotypes.

    PubMed

    Eyler, Lisa T; Vuoksimaa, Eero; Panizzon, Matthew S; Fennema-Notestine, Christine; Neale, Michael C; Chen, Chi-Hua; Jak, Amy; Franz, Carol E; Lyons, Michael J; Thompson, Wesley K; Spoon, Kelly M; Fischl, Bruce; Dale, Anders M; Kremen, William S

    2014-05-01

    Right-left regional cerebral differences are a feature of the human brain linked to functional abilities, aging, and neurodevelopmental and mental disorders. The role of genetic factors in structural asymmetry has been incompletely studied. We analyzed data from 515 individuals (130 monozygotic twin pairs, 97 dizygotic pairs, and 61 unpaired twins) from the Vietnam Era Twin Study of Aging to answer three questions about genetic determinants of brain structural asymmetry: First, does the magnitude of heritability differ for homologous regions in each hemisphere? Despite adequate power to detect regional differences, heritability estimates were not significantly larger in one hemisphere versus the other, except left > right inferior lateral ventricle heritability. Second, do different genetic factors influence left and right hemisphere size in homologous regions? Interhemispheric genetic correlations were high and significant; in only two subcortical regions (pallidum and accumbens) did the estimate statistically differ from 1.0. Thus, there was little evidence for different genetic influences on left and right hemisphere regions. Third, to what extent do genetic factors influence variability in left-right size differences? There was no evidence that variation in asymmetry (i.e., the size difference) of left and right homologous regions was genetically determined, except in pallidum and accumbens. Our findings suggest that genetic factors do not play a significant role in determining individual variation in the degree of regional cortical size asymmetries measured with MRI, although they may do so for volume of some subcortical structures. Despite varying interpretations of existing data, we view the present results as consistent with previous findings.

  1. Twin Peaks (B/W)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Twin Peaks are modest-size hills to the southwest of the Mars Pathfinder landing site. They were discovered on the first panoramas taken by the IMP camera on the 4th of July, 1997, and subsequently identified in Viking Orbiter images taken over 20 years ago. The peaks are approximately 30-35 meters (-100 feet) tall. North Twin is approximately 860 meters (2800 feet) from the lander, and South Twin is about a kilometer away (3300 feet). The scene includes bouldery ridges and swales or 'hummocks' of flood debris that range from a few tens of meters away from the lander to the distance of the South Twin Peak. The large rock at the right edge of the scene is nicknamed 'Hippo'. This rock is about a meter (3 feet) across and 25 meters (80 feet) distant.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  2. [Separation of pygopagous Siamese twins].

    PubMed

    Gille, P; Aubert, D; Mourot, M; François, J Y; Nachin, P; Delafin, J; Bonneville, J F; Cordier, A; Rousseaux, D; Monnier, G

    1983-01-01

    The successful separation of pygopagous twins is described. The sacrum formed a common canal since S 1 to coccyx with two medullary cords side to side and diastematomyelia with, at this level, two dural sacks. In each baby there was small atrophy in one lower limb. There were two opposite vulvovaginal ducts and two recto-perineal fistules.

  3. Do Twin Boundaries Always Strengthen Metal Nanowires?

    PubMed

    Zhang, Yongfeng; Huang, Hanchen

    2009-01-01

    It has been widely reported that twin boundaries strengthen nanowires regardless of their morphology-that is, the strength of nanowires goes up as twin spacing goes down. This article shows that twin boundaries do not always strengthen nanowires. Using classical molecular dynamics simulations, the authors show that whether twin boundaries strengthen nanowires depends on the necessary stress for dislocation nucleation, which in turn depends on surface morphologies. When nanowires are circular cylindrical, the necessary stress of dislocation nucleation is high and the presence of twin boundaries lowers this stress; twin boundaries soften nanowires. In contrast, when nanowires are square cylindrical, the necessary stress of dislocation nucleation is low, and a higher stress is required for dislocations to penetrate twin boundaries; they strengthen nanowires.

  4. Twinning in nanocrystalline fcc and bcc metals

    NASA Astrophysics Data System (ADS)

    Boyko, Vladimir S.; Kezerashvili, Roman Ya.

    2013-03-01

    The deformation twinning in nanocrystalline (nc) face-centered cubic (fcc) metals, body-centered cubic (bcc) metals, and in nc Si is analyzed. The phenomenological approach is used to make a bridge between microscopical mechanisms of twin nucleation and macroscopical characteristics of twinning with different crystal structures and to calculate the grain size range of the twinning propensity, the requisite external stress for twinning propagation in nc polycrystals, and the grain size at which the slip begins to prevail over the twinning. The developed approach allows to derive analytical expressions and estimate lower and and upper limits of grain sizes at which a twinning propensity is occurred. Results of calculations for the nc fcc metals Al, Cu, Ni, Pd, Au, nc bcc metals Ta, Fe, Mo, W, Nb, and nc diamond-cubic Si are compared with the experimental data, otherwise predictions are made.

  5. Spontaneous Posterior Uterine Rupture in Twin-Twin Transfusion Syndrome

    PubMed Central

    Smid, Marcela C.; Waltner-Toews, Rebecca; Goodnight, William

    2015-01-01

    Background The maternal and fetal risks of uterine distension in rapidly progressive twin-twin transfusion syndrome (TTTS) in the setting of prior uterine scar are poorly characterized. Case We present the case of a 42-year-old woman, G4P1201, at 21 weeks gestation with stage-1 TTTS who developed a spontaneous posterior uterine rupture necessitating emergent laparotomy and delivery of previable fetuses, possibly due to prior uterine scar from a displaced intrauterine device. Conclusion TTTS may be a risk factor for uterine rupture, including uterine rupture in atypical anatomic locations. Prior unrecognized uterine scars, including perforations, may magnify the risk for atypical uterine rupture in the setting of excessive uterine distension. PMID:26929874

  6. Unequal growth of twinned variants in boron-rich fivefold twinned nanowires

    NASA Astrophysics Data System (ADS)

    Yu, Zhiyang; Jiang, Jun; Zhu, Jing

    2017-01-01

    Boron-rich nanowires with fivefold twinned cross-sections were synthesized by conventional chemical vapor deposition. Interestingly, it is found that the lengths of twin variants in some rhombohedral based nanowires were substantially unequal, implying differences in the growth velocities of twin variants along longitudinal directions. This phenomenon is in sharp contrast with the developments of face-centered cubic (FCC) based fivefold twinned nanowires. We suggest the high density of microtwins in subcrystals was responsible for such kinetic growth behavior. More importantly, the current study implies that twin defects serve as an indispensable factor in prompting the kinetic growth of fivefold twinned nanowires.

  7. Genetic and environmental etiology of the relationship between childhood hyperactivity/inattention and conduct problems in a South Korean twin sample.

    PubMed

    Hur, Yoon-Mi

    2015-06-01

    Recently, there has been increased research into the etiology of the comorbidity between hyperactivity/inattention problems (HIP) and conduct problems (CP). However, the nature of the etiology of the comorbidity has remained unclear. Mothers of 507 pairs of twins, comprised of 221 monozygotic (MZ) and 286 dizygotic (DZ) twin pairs aged from 6 to 13 years (mean = 9.6 years; SD = 2.0 years), completed the HIP and the CP scale of the Strengths and Difficulties Questionnaire (SDQ) via a telephone interview. The phenotypic correlation between HIP and CP was 0.43 (p < .01). MZ and DZ twin correlations were, respectively, 0.48 (95%CI: 0.37-0.58) and 0.06 (95% CI: -0.06-0.19) for HIP and 0.38 (95% CI: 0.26-0.49) and 0.35 (95% CI: 0.25-0.45) for CP. The bivariate model-fitting results revealed additive genetic correlation of 1.0 (95% CI: 0.72-1.00), a complete overlap of additive genetic variance component between HIP and CP, supporting the importance of correlated additive genetic risk factors for the comorbid condition of HIP and CP. HIP was additionally influenced by non-additive genetic factors that did not contribute to the relationship between HIP and CP. There was a significant but moderate child-specific environmental correlation (r e = 0.37) between HIP and CP. CP was additionally influenced by shared family environmental influences. While the results of the present study are generally consistent with the findings from Western twin studies of the relationship between HIP and CP, they add a new finding to the extant literature by showing that it is additive rather than non-additive genetic factors that are responsible for the co-occurrence of HIP and CP.

  8. Why the healing gods are twins.

    PubMed

    Hankoff, L D

    1977-01-01

    The association of twins with health-giving powers is widespread in mythology, folklore, and religion. The Ashvins of the Rig-Veda, the classical Dioscuri, and the early Christian saints Cosmos and Damian are among the many examples of twins divinely empowered in the area of health and fertility. A characteristic set of attributes of twins recurs in different mythologies of wide distribution. In addition to healing, divine twins are often empowered with the ability to revive the dead, increase the fertility of man, animals, and crops, influence the weather, predict the future, and insure victory in battle. In some traditional societies these special attributes are thought to extend to all of the twins and their parents in the tribe.Ancient and primitive societies supposed that the birth of twins was associated with divine influence, the mother having been visited or otherwise affected by supernatural powers. A frequent explanation was that twins were the result of superfetation, a divine impregnation occurring along with that by the lawful husband. The specific powers of divine twins appear to be a reflection of the particular form of origin of twins through divine interference with the fertilization process. The twins thus share some of the powers of the divine parent, particularly those pertaining to fertility. Their dual paternity and its inherent competition is related to their martial interests as well as their ability to resolve ambivalent or ambiguous situations and predict outcomes.

  9. Deformation twinning: Influence of strain rate

    SciTech Connect

    Gray, G.T. III

    1993-11-01

    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 shock 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.

  10. Why the Healing Gods Are Twins

    PubMed Central

    Hankoff, Leon D.

    1977-01-01

    The association of twins with health-giving powers is widespread in mythology, folklore, and religion. The Ashvins of the Rig-Veda, the classical Dioscuri, and the early Christian saints Cosmos and Damian are among the many examples of twins divinely empowered in the area of health and fertility. A characteristic set of attributes of twins recurs in different mythologies of wide distribution. In addition to healing, divine twins are often empowered with the ability to revive the dead, increase the fertility of man, animals, and crops, influence the weather, predict the future, and insure victory in battle. In some traditional societies these special attributes are thought to extend to all of the twins and their parents in the tribe. Ancient and primitive societies supposed that the birth of twins was associated with divine influence, the mother having been visited or otherwise affected by supernatural powers. A frequent explanation was that twins were the result of superfetation, a divine impregnation occurring along with that by the lawful husband. The specific powers of divine twins appear to be a reflection of the particular form of origin of twins through divine interference with the fertilization process. The twins thus share some of the powers of the divine parent, particularly those pertaining to fertility. Their dual paternity and its inherent competition is related to their martial interests as well as their ability to resolve ambivalent or ambiguous situations and predict outcomes. PMID:560764

  11. Fingerprint recognition with identical twin fingerprints.

    PubMed

    Tao, Xunqiang; Chen, Xinjian; Yang, Xin; Tian, Jie

    2012-01-01

    Fingerprint recognition with identical twins is a challenging task due to the closest genetics-based relationship existing in the identical twins. Several pioneers have analyzed the similarity between twins' fingerprints. In this work we continue to investigate the topic of the similarity of identical twin fingerprints. Our study was tested based on a large identical twin fingerprint database that contains 83 twin pairs, 4 fingers per individual and six impressions per finger: 3984 (83*2*4*6) images. Compared to the previous work, our contributions are summarized as follows: (1) Two state-of-the-art fingerprint identification methods: P071 and VeriFinger 6.1 were used, rather than one fingerprint identification method in previous studies. (2) Six impressions per finger were captured, rather than just one impression, which makes the genuine distribution of matching scores more realistic. (3) A larger sample (83 pairs) was collected. (4) A novel statistical analysis, which aims at showing the probability distribution of the fingerprint types for the corresponding fingers of identical twins which have same fingerprint type, has been conducted. (5) A novel analysis, which aims at showing which finger from identical twins has higher probability of having same fingerprint type, has been conducted. Our results showed that: (a) A state-of-the-art automatic fingerprint verification system can distinguish identical twins without drastic degradation in performance. (b) The chance that the fingerprints have the same type from identical twins is 0.7440, comparing to 0.3215 from non-identical twins. (c) For the corresponding fingers of identical twins which have same fingerprint type, the probability distribution of five major fingerprint types is similar to the probability distribution for all the fingers' fingerprint type. (d) For each of four fingers of identical twins, the probability of having same fingerprint type is similar.

  12. Is That Me or My Twin? Lack of Self-Face Recognition Advantage in Identical Twins

    PubMed Central

    Martini, Matteo; Bufalari, Ilaria; Stazi, Maria Antonietta; Aglioti, Salvatore Maria

    2015-01-01

    Despite the increasing interest in twin studies and the stunning amount of research on face recognition, the ability of adult identical twins to discriminate their own faces from those of their co-twins has been scarcely investigated. One’s own face is the most distinctive feature of the bodily self, and people typically show a clear advantage in recognizing their own face even more than other very familiar identities. Given the very high level of resemblance of their faces, monozygotic twins represent a unique model for exploring self-face processing. Herein we examined the ability of monozygotic twins to distinguish their own face from the face of their co-twin and of a highly familiar individual. Results show that twins equally recognize their own face and their twin’s face. This lack of self-face advantage was negatively predicted by how much they felt physically similar to their co-twin and by their anxious or avoidant attachment style. We speculate that in monozygotic twins, the visual representation of the self-face overlaps with that of the co-twin. Thus, to distinguish the self from the co-twin, monozygotic twins have to rely much more than control participants on the multisensory integration processes upon which the sense of bodily self is based. Moreover, in keeping with the notion that attachment style influences perception of self and significant others, we propose that the observed self/co-twin confusion may depend upon insecure attachment. PMID:25853249

  13. The relationship between twin language, twins' close ties, and social competence.

    PubMed

    Hayashi, Chisato; Mikami, Hiroshi; Nishihara, Reiko; Maeda, Chiho; Hayakawa, Kazuo

    2014-02-01

    This study investigated the relationship between twin language, twins' close ties, and social competence in a prospective longitudinal study. We hypothesized that twins whose tie is close would be more likely to develop a twin language, and these twins would be less likely to develop social competence. In addition, we hypothesize that some environmental factors, such as having an older sibling, preschool attendance, zygosity, and sex are also related to twin language, twins' close ties, and social competence. At baseline in 1999 a mailed questionnaire survey was conducted, and a follow-up questionnaire was distributed in 2004 among 958 mothers. As a result, 516 respondents returned the questionnaire (53.9%). In this study, we used 261 twin pairs aged from 6 to 12 years (school-age children) for analysis, excluding those with missing values. In the present study, we found that zygosity and sex were associated with twins' close ties. Having an older sibling and preschool attendance did not affect the twins' close tie, twin language, or social competence. One of the most important findings was that social competence was not affected directly by twins' close tie, but was affected when a twin language was found.

  14. 158. Photocopy of transit book (taken from Twin Falls Canal ...

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

    158. Photocopy of transit book (taken from Twin Falls Canal Company Transit Book #404T, Page 3, #46, Division One). START OF MAIN CANAL SURVEY, TWIN FALLS COUNTY, MILNER, IDAHO. - 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

  15. 155. Photocopy of transit book (taken from Twin Falls Canal ...

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

    155. Photocopy of transit book (taken from Twin Falls Canal Company Surveyor's Transit Book #405T, Page 1, #46 Division One). STATEMENT RE: SURVEY ALIGNMENT 3/03, TWIN FALLS COUNTY, MILNER, IDAHO. - 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

  16. 154. Photocopy of transit book (taken from Twin Falls Canal ...

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

    154. Photocopy of transit book (taken from Twin Falls Canal Company Surveyor's Transit Book #405T, Page 2, #46 Division One). STATEMENT OF SIGHT-SETTING FOR 1903 SURVEY TO ALIGN SOUTH SIDE CANAL, TWIN FALLS COUNTY, MILNER, IDAHO. - 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

  17. 192. Photocopy of drawing, Twin Falls Canal Company, date unknown. ...

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

    192. Photocopy of drawing, Twin Falls Canal Company, date unknown. TOPOGRAPHICAL MAP (DAM DRAWN IN), MILNER SITE, TWIN FALLS COUNTY, MILNER, IDAHO; RIGHT SIDE OF MAP (LEFT ON ID-15-183). - 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

  18. 183. Photocopy of map (Twin Falls Canal Company). TOPOGRAPHICAL MAP ...

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

    183. Photocopy of map (Twin Falls Canal Company). TOPOGRAPHICAL MAP OF MILNER DAM SITE, TWIN FALLS COUNTY, MILNER, IDAHO; MAP, LEFT SIDE ONLY. CROSS REFERENCE: ID-15-192. - 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

  19. 187. Photocopy of drawing, Twin Falls Canal Company, date unknown. ...

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

    187. Photocopy of drawing, Twin Falls Canal Company, date unknown. TOPOGRAPHICAL MAP OF MILNER DAM LOCATION, TWIN FALLS COUNTY, MILNER, IDAHO; BLUEPRINT MAP. - 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

  20. 157. Photocopy of drawing (taken from Twin Falls Canal Company ...

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

    157. Photocopy of drawing (taken from Twin Falls Canal Company Field Book #360, Page 75, entitled, 'Clay-Seam Cut-Off.' Cross-Reference: ID-15-153). MILNER DAM SURVEY, TWIN FALLS COUNTY, MILNER, IDAHO. - 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

  1. 153. Photocopy of drawing (taken from Twin Falls Canal Company ...

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

    153. Photocopy of drawing (taken from Twin Falls Canal Company Field Book #360, Page 74, entitled, 'Clay-Seam Cut-Off.' Cross-Reference: ID-15-157). MILNER DAM SURVEY, TWIN FALLS COUNTY, MILNER, IDAHO. - 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

  2. 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…

  3. Quantum-mechanical twin paradox

    NASA Astrophysics Data System (ADS)

    Franson, J. D.

    2016-10-01

    In the twin paradox of special relativity, an observer that travels along an accelerated trajectory at a high velocity will experience a smaller amount of elapsed time than an observer that remains at rest. This illustrates the fact that time is relative unlike the situation in classical physics where time is absolute. In a recent paper, Bushev et al (2016 New J. Phys. 18 093050) showed that the twin paradox can also be demonstrated using a single electron that functions as a quantum-mechanical clock. The wave function of the electron can travel along two different paths simultaneously, which allows a measurement of the difference in proper times along the two trajectories using a single particle. Quantum interference effects show that time cannot be thought of as a classical parameter even when associated with a single clock or observer.

  4. Twins eye study in Tasmania (TEST): rationale and methodology to recruit and examine twins.

    PubMed

    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

    2009-10-01

    Visual impairment is a leading cause of morbidity and poor quality of life in our community. Unravelling the mechanisms underpinning important blinding diseases could allow 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) utilizing 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.

  5. 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

  6. Macrodeformation Twins in Single-Crystal Aluminum

    NASA Astrophysics Data System (ADS)

    Zhao, F.; Wang, L.; Fan, D.; Bie, B. X.; Zhou, X. M.; Suo, T.; Li, Y. L.; Chen, M. W.; Liu, C. L.; Qi, M. L.; Zhu, M. H.; Luo, S. N.

    2016-02-01

    Deformation twinning in pure aluminum has been considered to be a unique property of nanostructured aluminum. A lingering mystery is whether deformation twinning occurs in coarse-grained or single-crystal aluminum at scales beyond nanotwins. Here, we present the first experimental demonstration of macrodeformation twins in single-crystal aluminum formed under an ultrahigh strain rate (˜106 s-1 ) and large shear strain (200%) via dynamic equal channel angular pressing. Large-scale molecular dynamics simulations suggest that the frustration of subsonic dislocation motion leads to transonic deformation twinning. Deformation twinning is rooted in the rate dependences of dislocation motion and twinning, which are coupled, complementary processes during severe plastic deformation under ultrahigh strain rates.

  7. A Powerful Twin Arrives

    NASA Astrophysics Data System (ADS)

    1999-11-01

    First Images from FORS2 at VLT KUEYEN on Paranal The first, major astronomical instrument to be installed at the ESO Very Large Telescope (VLT) was FORS1 ( FO cal R educer and S pectrograph) in September 1998. Immediately after being attached to the Cassegrain focus of the first 8.2-m Unit Telescope, ANTU , it produced a series of spectacular images, cf. ESO PR 14/98. Many important observations have since been made with this outstanding facility. Now FORS2 , its powerful twin, has been installed at the second VLT Unit Telescope, KUEYEN . It is the fourth major instrument at the VLT after FORS1 , ISAAC and UVES.. The FORS2 Commissioning Team that is busy installing and testing this large and complex instrument reports that "First Light" was successfully achieved already on October 29, 1999, only two days after FORS2 was first mounted at the Cassegrain focus. Since then, various observation modes have been carefully tested, including normal and high-resolution imaging, echelle and multi-object spectroscopy, as well as fast photometry with millisecond time resolution. A number of fine images were obtained during this work, some of which are made available with the present Press Release. The FORS instruments ESO PR Photo 40a/99 ESO PR Photo 40a/99 [Preview - JPEG: 400 x 345 pix - 203k] [Normal - JPEG: 800 x 689 pix - 563kb] [Full-Res - JPEG: 1280 x 1103 pix - 666kb] Caption to PR Photo 40a/99: This digital photo shows the twin instruments, FORS2 at KUEYEN (in the foreground) and FORS1 at ANTU, seen in the background through the open ventilation doors in the two telescope enclosures. Although they look alike, the two instruments have specific functions, as described in the text. FORS1 and FORS2 are the products of one of the most thorough and advanced technological studies ever made of a ground-based astronomical instrument. They have been specifically designed to investigate the faintest and most remote objects in the universe. They are "multi-mode instruments" that

  8. Exotic quarks in Twin Higgs models

    SciTech Connect

    Cheng, Hsin -Chia; Jung, Sunghoon; Salvioni, Ennio; Tsai, Yuhsin

    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 the 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.

  9. Partial Meissner effect in superconductors with twins

    SciTech Connect

    Gurevich, A.L.; Mints, R.G. )

    1988-11-01

    Superconductivity of twinning planes, arising at critical temperature T/sub c/ exceeding the bulk point T/sub co/, may prove to be important for the understanding of the properties of high-temperature superconductors with well-developed twinning structure. This paper shows that regardless of a specific mechanism of superconductivity, twins at T/sub c/>T/sub co/ act as seeds for the growth of metastable superconducting domains whose order parameter phases differ by {pi}.

  10. 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

  11. 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

  12. 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.

  13. 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…

  14. Twin vaginal delivery: innovate or abdicate.

    PubMed

    Easter, Sarah Rae; Taouk, Laura; Schulkin, Jay; Robinson, Julian N

    2017-02-07

    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

  15. Siamese twins in the United Arab Emirates.

    PubMed

    el-Gohary, M A

    1998-03-01

    In the years 1985-1992, ten pairs of conjoined twins were born in the United Arab Emirates (UAE): one dicephalus, two teratopagi, and seven thoracoomphalopagi, one of which was still-born and three who were cared for in other hospitals. The first pair of thoraco-omphalopagus twins died of acute lymphoblastic leukaemia 6 months after successful separation. The management of the third set of twins gave rise to moral and ethical problems often encountered in such situations, while one of the teratopagi was a unique case of a parasite projecting from the mouth of the normal twin.

  16. Common plankton of Twin Lakes, Colorado

    SciTech Connect

    Lieberman, D.M.

    1983-02-01

    A series of studies is being performed to evaluate the effects of the Mt. Elbert Pumped-Storage Powerplant on the ecology of Twin Lakes. Twin Lakes are a pair of connected dimictic lakes, formed as the result of glacial action on alluvial deposits. This report presents a taxonomic species study of the common plankton collected since 1974 from Twin Lakes. A total of 11 zooplankters and 14 phytoplankters were identified from the limnetic zone of Twin Lakes and the associated Mt. Elbert Forebay. The four divisions of zooplankton included four species of Rotifera (rotifer), three species of Copepoda (copepod), three species of Cladocera (cladoceran), and one species of Mysidacea (opossum shrimp).

  17. Atomistic deformation mechanisms in twinned copper nanospheres.

    PubMed

    Bian, Jianjun; Niu, Xinrui; Zhang, Hao; Wang, Gangfeng

    2014-01-01

    In the present study, we perform molecular dynamic simulations to investigate the compression response and atomistic deformation mechanisms of twinned nanospheres. The relationship between load and compression depth is calculated for various twin spacing and loading directions. Then, the overall elastic properties and the underlying plastic deformation mechanisms are illuminated. Twin boundaries (TBs) act as obstacles to dislocation motion and lead to strengthening. As the loading direction varies, the plastic deformation transfers from dislocations intersecting with TBs, slipping parallel to TBs, and then to being restrained by TBs. The strengthening of TBs depends strongly on the twin spacing.

  18. 11. Photographic copy of copy of Twin Lakes Outlet Works ...

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

    11. Photographic copy of copy of Twin Lakes Outlet Works construction drawing dated January 15, 1951. Drawn by W.A. Doe for the Twin Lakes Reservoir and Canal Co. (copy in possession of Bureau of Reclamation, location of original unknown) 'AS CONSTRUCTED' PLANS OF 1949-1950, REHABILITATION OF TWIN LAKES RESERVOIR OUTLET WORKS, DETAILS OF UPSTREAM WING WALLS. - Twin Lakes Dam & Outlet Works, Beneath Twin Lakes Reservoir, T11S, R80W, S22, Twin Lakes, Lake County, CO

  19. 12. Photographic copy of copy of Twin Lakes Outlet Works ...

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

    12. Photographic copy of copy of Twin Lakes Outlet Works construction drawing dated January 15, 1951. Drawn by W.A. Doe for the Twin Lakes Reservoir and Canal Co. (copy in possession of Bureau of Reclamation, location of original unknown) 'AS CONSTRUCTED' PLANS OF 1949-50, REHABILITATION OF TWIN LAKES RESERVOIR OUTLET WORKS, DETAILS OF DISCHARGE BASIN. - Twin Lakes Dam & Outlet Works, Beneath Twin Lakes Reservoir, T11S, R80W, S22, Twin Lakes, Lake County, CO

  20. Weak phonon scattering effect of twin boundaries on thermal transmission

    PubMed Central

    Dong, Huicong; Xiao, Jianwei; Melnik, Roderick; Wen, Bin

    2016-01-01

    To study the effect of twin boundaries on thermal transmission, thermal conductivities of twinned diamond with different twin thicknesses have been studied by NEMD simulation. Results indicate that twin boundaries show a weak phonon scattering effect on thermal transmission, which is only caused by the additional twin boundaries’ thermal resistance. Moreover, according to phonon kinetic theory, this weak phonon scattering effect of twin boundaries is mainly caused by a slightly reduced average group velocity. PMID:26822675

  1. Weak phonon scattering effect of twin boundaries on thermal transmission.

    PubMed

    Dong, Huicong; Xiao, Jianwei; Melnik, Roderick; Wen, Bin

    2016-01-29

    To study the effect of twin boundaries on thermal transmission, thermal conductivities of twinned diamond with different twin thicknesses have been studied by NEMD simulation. Results indicate that twin boundaries show a weak phonon scattering effect on thermal transmission, which is only caused by the additional twin boundaries' thermal resistance. Moreover, according to phonon kinetic theory, this weak phonon scattering effect of twin boundaries is mainly caused by a slightly reduced average group velocity.

  2. [Social development of twins: the need for intervention to avoid adverse effects of twin language].

    PubMed

    Hayashi, Chisato; Hayakawa, Kazuo; Maeda, Chiho; Nishihara, Reiko; Onoi, Miyuki

    2008-10-01

    Social competence is one of the most important accomplishments of human development, and this skill in human relationships is learned through communication. Therefore, it is considered that delays in language development could be a barrier to building human relationships and social competence. Although it is well known that there are delays in language development in twins compared with that of singletons, little is known about how these linguistic delays affect the development of social competence. Because twin language is a language that is unique to each pair of twins and cannot be understood by either their mother or others, it may be assumed that the social competence of twins who have a twin language is less than that of twins who don't have a twin language. Therefore, in this prospective longitudinal study we also investigated the relationship between twin language and social competence. A mailed questionnaire survey was conducted in 958 mothers as a follow-up of a study conducted in 2004. As a result, 522 respondents returned the questionnaire (53.9%). In this study, we used only 256 twins aged 6- 12-years-old (school-age children) for analysis, excluding those with missing values. Multiple logistic regression analysis was employed. In the second child of twins, a low birth weight, the appearance of twin language and gestosis of the mother were positively related with social unbalance (OR = 1.846, 2.022 and 1.903). On the other hand, with the first child, however, there was no such link. The present results indicate that twin language might influence social competence in school-age children. It has been believed that linguistic intervention is unnecessary, because most twin language disappears spontaneously. However, early intervention, for example linguistic assistance by public health nurses or psychologists and early enrollment in a preschool may be necessary for twins with a twin language, to avoid adverse consequences in social competence at school-age.

  3. Chronic Placental Inflammation in Twin Pregnancies

    PubMed Central

    Bang, Heejin; Bae, Go Eun; Park, Ha Young; Kim, Yeon Mee; Choi, Suk-Joo; Oh, Soo-young; Roh, Cheong-Rae; Kim, Jung-Sun

    2015-01-01

    Background: Chronic placental inflammation, such as villitis of unknown etiology (VUE) and chronic chorioamnionitis (CCA), is considered a placental manifestation of maternal anti-fetal rejection. The aim of this study is to investigate its frequency in twin pregnancies compared to singleton pregnancies. Methods: Three hundred twin placentas and 1,270 singleton placentas were consecutively collected at a tertiary medical center in Seoul, Republic of Korea from 2009 to 2012. Hematoxylin and eosin sections of tissue samples (full-thickness placental disc and chorioamniotic membranes) were reviewed. Results: Non-basal VUE was more frequent in twin placentas than in singleton placentas (6.0% vs 3.2%, p < .05). In preterm birth, CCA was found less frequently in twin placentas than in singleton placentas (9.6% vs 14.8%, p < .05), reaching its peak at an earlier gestational age in twin placentas (29–32 weeks) than in singleton placentas (33–36 weeks). CCA was more frequent in twin pregnancies with babies of a different sex than with those with the same sex (13.8% vs 6.9%, p=.052). Separate dichorionic diamniotic twin placentas were affected by chronic deciduitis more frequently than singleton placentas (16.9% vs 9.7%, p<.05). Conclusions: The higher frequency of non-basal VUE in twin placentas and of CCA in twin placentas with different fetal sex supports the hypothesis that the underlying pathophysiological mechanism is maternal anti-fetal rejection related to increased fetal antigens in twin pregnancies. The peak of CCA at an earlier gestational age in twin placentas than in singleton placentas suggests that CCA is influenced by placental maturation. PMID:26459409

  4. NEC in Twin Pregnancies: Incidence and Outcomes

    PubMed Central

    C Burjonrappa, Sathyaprasad; Shea, Brian; Goorah, Diya

    2014-01-01

    Background: Necrotizing Enterocolitis (NEC) is the most common gastrointestinal emergency in neonates. Previously established risk factors for the development of NEC include prematurity and low birth weight. However, it is not clear to date as to whether the etiology of NEC is due to host, environmental, or yet other unknown factors. We analyzed the differences in incidence of NEC in twin pregnancies to further clarify its etio-pathogenesis. Methods: After IRB approval, a retrospective search of the medical records of the Department of Pediatric Surgery was done to identify all the neonates treated for surgical NEC from 2006-2013. Patients that had been treated for NEC elsewhere and subsequently transferred in to our facility were excluded. The medical records of the resulting 45 patients were then analyzed for demographics, antenatal screening, risk factors, treatment (medical and surgical), and outcomes. The resulting data was then analyzed using relative risk calculations and standard statistical tests. Results: Of the 45 patients who developed surgical NEC, 9 neonates (20%) were born of a twin pregnancy. There were no cases in which both twin A and twin B developed NEC. NEC in twin pregnancy neonates showed a female preponderance (p less than 0.0001) and developed universally in the first born of the twins. Birth weight, time of onset of NEC, hospital stay and mortality were similar between twin and non-twin NEC. There was an average lead-time of three weeks to development of NEC in both singletons and twin pregnancies. Conclusion: There is a remarkable higher incidence of NEC amongst twins. Abnormal colonization of the gastrointestinal tract appears to be an immediate postpartum event. NEC in twin pregnancy does not appear to have a deleterious outcome compared to NEC in singleton pregnancy. PMID:26023516

  5. A twin sibling with Prader-Willi syndrome caused by type 2 microdeletion following assisted reproductive technology: A case report

    PubMed Central

    HAN, JI YOON; PARK, JOONHONG; JANG, WOORI; CHAE, HYOJIN; KIM, MYUNGSHIN; KIM, YONGGOO

    2016-01-01

    Prader-Willi syndrome (PWS) is a neurobehavioral imprinting disorder, which arises due to an absence of paternally expressed genes within the 15q11.2-q13 region. This occurs via one of the three main genetic mechanisms, as follows: Deletion of the paternally inherited 15q11.2-q13 region, maternal uniparental disomy and imprinting defect. Recent studies have reported an association between imprinting disorders and assisted reproductive technologies (ART). The current study presents a 6-year-old female patient who is a dizygotic twin, in which one was born with de novo microdeletion at 15q11.2-q13.1 following in vitro fertilization. The patient had characteristic facial features including narrow bifrontal diameter, strabismus, downturned mouth, feeding problems and generalized hypotonia during infancy, developmental delay, mental retardation and rapid weight gain. Based upon phenotypic resemblance and the medical records, methylation-specific multiplex ligation-dependent probe amplification and array-based comparative genome hybridization analyses demonstrate type 2 microdeletion between breaking point 2 (BP2) and BP3, which occur from MKRN3 through HERC2 at 15q11.2-q13.1. To the best of our knowledge, the present study is the first to report a PWS case born following ART reported in South Korea. In addition to previous studies, the present study contributes to the consensus regarding genotype-phenotype comparisons in this respect. PMID:27330749

  6. Genetic influence on age at first birth of female twins born in the UK, 1919-68.

    PubMed

    Tropf, Felix C; Barban, Nicola; Mills, Melinda C; Snieder, Harold; Mandemakers, Jornt J

    2015-01-01

    Using a sample of monozygotic (945, 42 per cent) and dizygotic (1,329, 58 per cent) twin pairs born 1919-68 in the UK, we applied innovative tobit models to investigate genetic and environmental influences on age at first birth (AFB). We found that a substantial part (40 per cent) of the variation in AFB is caused by latent family characteristics. Genetic dispositions (26 per cent) play a more important role than the shared environment of siblings (14 per cent), with the non-shared environment/measurement error having the strongest influence (60 per cent). Like previous studies, this study reveals marked changes in estimates over time, and supports the idea that environmental constraints (war or economic crisis) suppress and normative freedom (sexual revolution) promotes the activation of genetic predispositions that affect fertility. We show that the exclusion of censored information (i.e., on the childless) by previous studies biased their results.

  7. 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.

  8. Clinical and echographic features of in utero cardiac dysfunction in the recipient twin in twin-twin transfusion syndrome.

    PubMed Central

    Zosmer, N; Bajoria, R; Weiner, E; Rigby, M; Vaughan, J; Fisk, N M

    1994-01-01

    OBJECTIVE--Fetal twin-twin transfusion syndrome (TTTS) presenting in the second trimester has been associated with almost no perinatal survival until recently, when serial drainage of amniotic fluid has improved the prognosis to 70%-80%. Most recipient twins now survive but develop cardiac dysfunction. The study was undertaken to evaluate the abnormal echocardiographic features and clinical complications of cardiac disease in the recipient twin of TTTS. DESIGN--Antenatal and postnatal echocardiographic and clinical observational study. SETTING--Antenatal studies in a tertiary referral centre. Postnatal management and follow up were performed by the same paediatric cardiologist, either at the obstetric hospital or at the regional referral centre. PATIENTS--Twin pregnancies complicated by TTTS with severe polyhydramnios diagnosed earlier than 25 weeks that proceeded until viability (n = 5). INTERVENTION--Serial fetal echocardiography with colour Doppler. Postnatal echocardiography in the first week and between two and seven months. Serial amnioreduction was performed in all pregnancies. Digoxin treatment, pericardiocentesis, paracentesis, or laser ablation of placental anastomoses was undertaken when there was hydrops. RESULTS--Increased cardiothoracic ratio and tricuspid regurgitation were seen in all recipient twins. High pulmonary artery velocities developed in three. One recipient twin died a week after delivery of endocardial fibroelastosis and infundibular pulmonary stenosis. Two other had balloon dilatation for pulmonary stenosis, one shortly after birth and one at four months. A further twin has apical thickening of the right ventricle at six months. The remaining recipient twin had normal echocardiographic findings at follow up. CONCLUSION--This report characterises for the first time a cardiac disease acquired in utero in the recipient twin in pregnancies complicated by TTTS. Clinical manifestations in utero range from mild to critical pulmonary stenosis or

  9. Twin-Foucault imaging method

    NASA Astrophysics Data System (ADS)

    Harada, Ken

    2012-02-01

    A method of Lorentz electron microscopy, which enables observation two Foucault images simultaneously by using an electron biprism instead of an objective aperture, was developed. The electron biprism is installed between two electron beams deflected by 180° magnetic domains. Potential applied to the biprism deflects the two electron beams further, and two Foucault images with reversed contrast are then obtained in one visual field. The twin Foucault images are able to extract the magnetic domain structures and to reconstruct an ordinary electron micrograph. The developed Foucault method was demonstrated with a 180° domain structure of manganite La0.825Sr0.175MnO3.

  10. Ocular findings in conjoined (Siamese) twins.

    PubMed

    Mansour, A M; Mansour, N; Rosenberg, H S

    1991-01-01

    Conjoined twinning is a rare form of congenital anomaly. The ocular findings in six sets of conjoined twins as well as those reported elsewhere include abnormal optic nerve decussation, pseudosynophthalmos, microphthalmia, abnormal eyelids, orbital encephalocele, occipital encephalocele, and eyelid coloboma. These findings are interpreted as due to deformations from appositional fusion-related factors or malformations from developmental factors.

  11. Optimal nutrition for improved twin pregnancy outcome.

    PubMed

    Goodnight, William; Newman, Roger

    2009-11-01

    Twin pregnancies contribute a disproportionate degree to perinatal morbidity, partly because of increased risks of low birth weight and prematurity. Although the cause of the morbidity is multifactorial, attention to twin-specific maternal nutrition may be beneficial in achieving optimal fetal growth and birth weight. Achievement of body mass index (BMI)-specific weight gain goals, micronutrient and macronutrient supplementation specific to the physiology of twin gestations, and carbohydrate-controlled diets are recommended for optimal twin growth and pregnancy outcomes. The daily recommended caloric intake for normal-BMI women with twins is 40-45 kcal/kg each day, and iron, folate, calcium, magnesium, and zinc supplementation is recommended beyond a usual prenatal vitamin. Daily supplementation of docosahexaenoic acid and vitamin D should also be considered. Multiple gestation-specific prenatal care settings with a focus on nutritional interventions improve birth weight and length of gestation and should be considered for the care of women carrying multiples. Antepartum lactation consultation can also improve the rate of postpartum breastfeeding in twin pregnancies. Twin gestation-specific nutritional interventions seem effective in improving the outcome of these pregnancies and should be emphasized in the antepartum care of multiple gestations. This review examines the available evidence and offers recommendations for twin pregnancy-specific nutritional interventions.

  12. [Hungarian twin studies: results of four decades].

    PubMed

    Tárnoki, Ádám Domonkos; Tárnoki, Dávid László; Horváth, Tamás; Métneki, Júlia; Littvay, Levente

    2013-10-06

    Twin studies play a role in examining the contribution of genetic variations and environmental factors responsible for the determination of phenotypic variables and of genetic linkage between genotypes. Hungarian twin studies, supported by three twin registries (among them two twin-database), date back to 1970s. Studies mainly focused on various congenital abnormalities, the effect of contraceptive pills and folic acid on the frequency of twin pregnancies, as well as psychosexual and alcohol consumptional behaviors. Monogenic Mendelian inheritance of lactose (mal)absorption was demonstrated for the first time. Hungarian Twin Registry was founded in 2007, which contributed to the current understanding on the background of several disorders, e.g. metabolic syndrome and atherosclerosis. As part of an international twin study, among others, arterial stiffness, central blood pressure, carotid intima/media thickness, venous biomechanics, body composition, lung function and smoking characteristics were also assessed. Absence of genetic background in non-alcoholic fatty liver disease and high inheritance of carotid plaque characteristics were demonstrated for the first time. The review also aims to summarize future plans of the Hungarian Twin Registry.

  13. Cysticercosis with an Orbital Tropism in Twins

    PubMed Central

    Lee, Bradford W.; Kumar, Usha R.; Lin, Jonathan H.; Amaro, Deirdre E.; Kikkawa, Don O.; Alameddine, Ramzi M.; Lowe, Maureen C.; Hilger, Peter A.; Vinetz, Joseph M.; Korn, Bobby S.

    2015-01-01

    Two fraternal twin sisters developed cysticercosis localizing to the right lateral orbit over the same period after a presumed common-source exposure in China. This case demonstrates that cysticercosis can be related to travel. Similar temporal and spatial occurrences of these infections suggest a genetic tropism of the infecting organism in these twins. PMID:26217041

  14. Twinning: A Marker for Biological Insults

    ERIC Educational Resources Information Center

    Howard, Robert G.; Brown, Anne M.

    1970-01-01

    Analysis of various statistics from birth records of 317 consecutive births revealed that twins are nonrepresentative of newborns with respect to birth weight and gestation, with male pairs to same-sex pairs the least representative. Differences between Negro and Caucasian twins were also found. (MH)

  15. Colorado Longitudinal Twin Study of Reading Disability

    ERIC Educational Resources Information Center

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

    2007-01-01

    The primary objectives of the present study are to introduce the Colorado Longitudinal Twin Study of Reading Disability, the first longitudinal twin study in which subjects have been specifically selected for having a history of reading difficulties, and to present some initial assessments of the stability of reading performance and cognitive…

  16. Entropic interaction between fluctuating twin boundaries

    NASA Astrophysics Data System (ADS)

    Chen, Dengke; Kulkarni, Yashashree

    2015-11-01

    Nanotwinned metals have opened up exciting avenues for the design of high-strength, high-ductility materials owing to the extraordinary properties of twin boundaries. The recent advances in the fabrication of nanostructured materials with twin lamella on the order of a mere few atomic layers call for a closer examination of the stability of these structural motifs, especially at high temperatures. This paper presents a study of the entropic interaction between fluctuating twin boundaries by way of atomistic simulations and statistical mechanics based analysis. The simulations reveal that fluctuations of twin boundaries are considerably enhanced in the presence of adjoining twin boundaries as their spacing, d, decreases. In addition, the theoretical analysis shows that fluctuating twin boundaries indeed exhibit an attractive entropic interaction which enhances their thermal fluctuations and that the entropic force decreases as 1 /d2. This finite temperature interaction between twin boundaries is fundamentally distinct from the well-known repulsive entropic interaction followed by fluctuating lipid membranes as well as many crystalline membranes and interfaces. This rather surprising attraction between fluctuating twin boundaries is attributed to their shear coupled normal motion.

  17. Mapping the association between back pain and type 2 diabetes: A cross-sectional and longitudinal study of adult Spanish twins

    PubMed Central

    Ordoñana, Juan; Ferreira, Paulo

    2017-01-01

    Background Back pain and type 2 diabetes often co-occur, resulting in greater impact on people’s health and complexity in their care. Plausible causal mechanisms for this association have been proposed, yet the nature of the link remains unclear. We therefore explored the direction of the association between type 2 diabetes and chronic back pain in twins, controlling for genetics and early environmental confounding. Methods 2,096 and 1,098 twins were included in the cross-sectional and longitudinal analyses, respectively. Any or severe (≥ 9) low back pain (LBP), neck pain (NP), and spinal pain (concurrent LBP and NP) and type 2 diabetes were investigated. Sequential analyses were performed using logistic regression. Firstly, twins were analysed unpaired (adjusted age and gender): total sample analyses. Then, to control for genetic and shared environmental factors, a co-twin case-control analysis was performed including monozygotic and dizygotic twin pairs discordant for back pain (cross-sectional only). Results In the cross-sectional total sample analyses, type 2 diabetes was associated with chronic spinal pain (OR 1.61; 95%CI 1.12 to 2.31), severe chronic spinal pain (OR 3.33; 95%CI 1.47 to 7.53), chronic NP (OR 1.37; 95%CI 1.01 to 1.85), severe chronic NP (OR 2.28; 95%CI 1.24 to 4.21), and severe chronic LBP (OR 1.63; 95%CI 1.00 to 2.64). After further adjustment for genetic and shared environmental factors, none of the associations remained significant. The longitudinal analyses indicated that the presence of type 2 diabetes did not increase the risk of future back pain, or vice-versa, after two to four years. Conclusions Chronic back pain (spinal pain, NP, or LBP) was associated with the prevalence of type 2 diabetes. Associations are stronger for severe cases of pain. Future research should investigate the temporal relationships between these conditions with longer follow up in twins. PMID:28369107

  18. Twins in Ancient Greece: a synopsis.

    PubMed

    Malamitsi-Puchner, Ariadne

    2016-01-01

    This brief outline associates twins with several aspects of life in Ancient Greece. In Greek mythology twins caused ambivalent reactions and were believed to have ambivalent feelings for each other. Very often, they were viewed as the representatives of the dualistic nature of the universe. Heteropaternal superfecundation, which dominates in ancient myths, explains on one hand, the god-like qualities and, on the other hand, the mortal nature of many twins. An assumption is presented that legends referring to twins might reflect the territorial expansions of Ancient Greeks in Northern Mediterranean, around the Black Sea, in Asia Minor, as well as North East Africa. In conclusion, in Greek antiquity, twins have been used as transitional figures between myth and reality.

  19. Highlights from the 15th International Congress of Twin Studies/Twin Research: Differentiating MZ Co-twins Via SNPs; Mistaken Infant Twin-Singleton Hospital Registration; Narcolepsy With Cataplexy; Hearing Loss and Language Learning/Media Mentions: Broadway Musical Recalls Conjoined Hilton Twins; High Fashion Pair; Twins Turn 102; Insights From a Conjoined Twin Survivor.

    PubMed

    Segal, Nancy L

    2015-02-01

    Highlights from the 15th International Congress of Twin Studies are presented. The congress was held November 16-19, 2014 in Budapest, Hungary. This report is followed by summaries of research addressing the differentiation of MZ co-twins by single nucleotide polymorphisms (SNPs), an unusual error in infant twin-singleton hospital registration, twins with childhood-onset narcolepsy with cataplexy, and the parenting effects of hearing loss in one co-twin. Media interest in twins covers a new Broadway musical based on the conjoined twins Violet and Daisy Hilton, male twins becoming famous in fashion, twins who turned 102 and unique insights from a conjoined twin survivor. This article is dedicated to the memory of Elizabeth (Liz) Hamel, DZA twin who met her co-twin for the first time at age seventy-eight years. Liz and her co-twin, Ann Hunt, are listed in the 2015 Guinness Book of Records as the longest separated twins in the world.

  20. University of Washington Twin Registry: Construction and characteristics of a community-based twin registry

    PubMed Central

    Afari, Niloofar; Noonan, Carolyn; Goldberg, Jack; Edwards, Karen; Gadepalli, Kiran; Osterman, Bethany; Evanoff, Cynthia; Buchwald, Dedra

    2010-01-01

    The University of Washington Twin Registry is a community-based registry of twins identified from the Washington State Department of Licensing. A fortuitous quirk in the Washington State drivers' license and identification number assignment, and collaborative Washington State laws, permitted us to build a statewide registry. Since obtaining approval from the Washington State Attorney General, the Washington State Department of Licensing has provided us with information on over 26,000 newly licensed twins, and we continue to receive computerized records on approximately 80 new twins per week. The University of Washington Twin Registry is assembled by mailing each twin a recruitment packet that includes an information sheet, brochure, brief survey, and nominal gift. Once both members of a twin pair have completed the packet, the pair is enrolled in the Registry. As of June 2006, 2,287 adult twin pairs have enrolled in the Registry; about one half of these are female-female pairs. Among all twins, the average age is 32 years. Based on self-report, 52% of twins are MZ, 42% are DZ, and zygosity on 6% cannot yet be determined. We also have established a clinical protocol for collecting additional data and DNA from all twins participating in research studies requiring an in-person visit. The Registry has established policies and procedures to protect the confidentiality of twin data and guidelines for the use of the Registry by investigators. Plans for the further growth of the University of Washington Twin Registry and its use are discussed. PMID:17254446

  1. 159. Photocopy of written record (taken from Twin Falls Canal ...

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

    159. Photocopy of written record (taken from Twin Falls Canal Company Low Line Book #1, pp. 76,77). RECORD OF BORROW AT LOW LINE SIPHON. - 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

  2. 156. Photocopy of written record (taken from Twin Falls Canal ...

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

    156. Photocopy of written record (taken from Twin Falls Canal Company, Low Line Book #1, pp.2,3). LOW LINE CONTRACTORS AND BORROW RECORD. - 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

  3. Successful Separation of Omphalopagus Twins: A Case Report

    PubMed Central

    Patil, Prashant S; Kothari, Paras; Gupta, Abhaya; Kekre, Geeta; Dikshit, KV; Kamble, Ravi; Deshmukh, Shahaji

    2016-01-01

    Omphalopagus twins are conjoined twins sharing part of gastrointestinal system and abdominal wall. These types of twins have best chances of survival if successfully separated. We report a case of successfully separated omphalopagus twins at day six of life. PMID:26793597

  4. 117. COTTONWOOD CREEK SPILL, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, ...

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

    117. COTTONWOOD CREEK SPILL, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, IDAHO; CLOSE-UP OF OUTLET SIDE OF SPILL, 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

  5. Dislocation Mechanism of Twinning in Ni-Mn-Ga

    NASA Astrophysics Data System (ADS)

    Zárubová, N.; Ge, Y.; Gemperlová, J.; Gemperle, A.; Hannula, S.-P.

    2012-03-01

    Tensile tests were performed in situ in a transmission electron microscope to investigate the twinning mechanism in non-modulated Ni-Mn-Ga martensite. The reorientation of the twin variants occurs via twinning dislocations. Their generation and movement were followed; the glide plane and Burgers vector were verified. Individual twinning dislocations were visualized.

  6. Monozygotic twins with trisomy 18: a report of discordant phenotype.

    PubMed Central

    Schlessel, J S; Brown, W T; Lysikiewicz, A; Schiff, R; Zaslav, A L

    1990-01-01

    The predicted incidence of liveborn monozygotic trisomy 18 twins is one per million births. The first case of liveborn monozygotic trisomy 18 twins was reported in 1989 and we report a second case in which striking phenotypic discordance existed. The probability of monozygotic trisomy 18 twinning and the mechanisms for phenotypic discordance in trisomic twins is discussed. Images PMID:2246775

  7. 134. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN ...

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

    134. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN FALLS COUNTY, SOUTH OF HANSEN, IDAHO; VIEW OF LOW LINE AND POWER GATES, WEST 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

  8. 197. Photocopy of drawing, Twin Falls, Canal Company, date unknown. ...

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

    197. Photocopy of drawing, Twin Falls, Canal Company, date unknown. GATE STEMS AND LIFTING DEVICES, NO COUNTY; BLUEPRINT SKETCHES. - 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

  9. 132. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN ...

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

    132. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN FALLS COUNTY, SOUTH OF HANSEN, IDAHO; POWER GATES FOR HYDRO-ELECTRIC. - 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

  10. TWINS Observations of Oxygen ENA Flux

    NASA Astrophysics Data System (ADS)

    Alquiza, J. C.; Goldstein, J.; Gruntman, M.; McComas, D. J.; Redfern, J.; Valek, P. W.

    2009-12-01

    As part of the science objectives of the TWINS (Two Wide-angle Imaging Neutral-atom Spectrometers) mission, we aim to enhance the knowledge of the workings of our magnetosphere by contributing compositional information of the observed energetic neutral atom (ENA) flux from the two TWINS instruments. We will present images of oxygen (O) ENA flux varying over time and space. Results from a few cases of TWINS flight data of geomagnetic significance will be presented with this analysis. One such example is a simultaneous and continuous observation of a minor geomagnetic storm (-60 nT) on 11 Oct 2008 as seen by both TWINS instruments. Initial TWINS images of this event show evidences of low-altitude emissions (LAEs) near the limb of the Earth and ring current signatures as well. Our compositional analysis is based on the secondary electron pulse height (PH) distributions measured by TWINS. Secondary electrons are generated as ENAs pass through an ultra-thin carbon foil in the TWINS instrument apertures. The secondary electron (PH) distribution varys as a function of the ENA’s energy and mass. The observed PH functions are then compared to the secondary electron PH distributions determined during instrument calibration. The flight data are simply treated as a linear combination of the two anticipated and most abundant species of magnetospheric ENAs, i.e., hydrogen (H) and oxygen (O).

  11. Hypothesis test for synchronization: Twin surrogates revisited

    NASA Astrophysics Data System (ADS)

    Romano, M. Carmen; Thiel, Marco; Kurths, Jürgen; Mergenthaler, Konstantin; Engbert, Ralf

    2009-03-01

    The method of twin surrogates has been introduced to test for phase synchronization of complex systems in the case of passive experiments. In this paper we derive new analytical expressions for the number of twins depending on the size of the neighborhood, as well as on the length of the trajectory. This allows us to determine the optimal parameters for the generation of twin surrogates. Furthermore, we determine the quality of the twin surrogates with respect to several linear and nonlinear statistics depending on the parameters of the method. In the second part of the paper we perform a hypothesis test for phase synchronization in the case of experimental data from fixational eye movements. These miniature eye movements have been shown to play a central role in neural information processing underlying the perception of static visual scenes. The high number of data sets (21 subjects and 30 trials per person) allows us to compare the generated twin surrogates with the "natural" surrogates that correspond to the different trials. We show that the generated twin surrogates reproduce very well all linear and nonlinear characteristics of the underlying experimental system. The synchronization analysis of fixational eye movements by means of twin surrogates reveals that the synchronization between the left and right eye is significant, indicating that either the centers in the brain stem generating fixational eye movements are closely linked, or, alternatively that there is only one center controlling both eyes.

  12. On the twinning in ZnPd.

    PubMed

    Ivarsson, Dennis C A; Burkhardt, Ulrich; Heggen, Marc; Ormeci, Alim; Armbrüster, Marc

    2017-02-22

    The intermetallic compound ZnPd has demonstrated excellent catalytic properties in methanol steam reforming. While it is known that defects and microstructures influence the catalytic properties, little is known about the defects occurring in ZnPd. Due to recent advances in synthetic methods, coarse-grained ZnPd samples are accessible. This enables the detection and investigation of twinning in ZnPd by studying the twinned regions from the macroscopic scale by polarised light and electron backscattering diffraction (EBSD) down to the atomic scale by high-resolution transmission electron microscopy (HR-TEM). Twinning occurs in {101} and is coupled with a change in the c/a ratio in the vicinity of the twin boundary. Quantum chemical calculations result in only very small energy differences between the ideal and the twinned structure, explaining the experimentally observed thermal stability of the latter. The chemical bonding was investigated by the electron localizability indicator (ELI) and compared to the one in the ideal structure. The results confirm twinning along the {101} plane and demonstrate the high stability of the twin boundaries after formation.

  13. Mechanical twinning in small quartz crystals

    NASA Astrophysics Data System (ADS)

    Laughner, J. W.; Newnham, R. E.; Cross, L. E.

    1982-02-01

    Quartz is known to be ferrobielastic; that is, quartz crystals have domain states (Dauphiné twins) which differ in their elastic compliance values and which can be switched by an appropriately oriented stress. Polycrystalline quartz has also been reported (Tullis 1970) to show preferential orientation of these domains following application of large uniaxial stresses. These experiments were designed to study twinning of synthetic quartz “grains” (minimum size 0.07×0.07×0.02 cm) in specially-constructed composites and of grains in three natural quartz aggregates — a quartzite, a novaculite, and a jasper. Backreflection X-ray techniques were used to verify twinning in the composite grains, while special electroding and electrical detection allowed the twinning processes to be examined in “real time.” Small synthetic quartz crystals were found to behave identically to the massive samples previously studied. Electrical pulses due to the reversal of piezoelectric coefficient d 11 in twinned quartz were detected from quartzite and from the man-made composites. Novaculite also gave electrical pulses which were probably from twinning (evidenced by the correlation of expected and observed pulse sizes and shapes), while no pulses from the jaspers indicative of twinning were detected. Grain size distribution differences are considered the main structural reason for the different behaviors.

  14. 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.

  15. Teaching about twins: college courses and public lectures.

    PubMed

    Segal, Nancy L

    2013-12-01

    The present article describes teaching experiences and observations in college courses and public lectures on twins. It is concluded that much more information about twins, at both research and practical levels, requires general dissemination. This discussion is followed by reviews of recent twin research on the topics of obesity control, post-zygotic mutation, in vitro fertilization, and schisis-associated defects. Media reports of twins accused of rape, infant Chinese twins sold separately for profit, a twin CEO, and twins pursuing the same career are presented.

  16. Breastfeeding Twins: A Qualitative Study

    PubMed Central

    Alvur, Tuncay Muge; Kose, Dilek; Nemut, Tijen

    2013-01-01

    The purpose of this qualitative research was to explore the needs and difficulties of mothers who had multiple babies at Sakarya County by focusing on their breastfeeding experience. Ten mothers who gave birth to multiple infants participated in the study voluntarily. The framework method of data analysis was applied systematically both within and across cases, with categories and themes identified by reading transcripts of interviews. Major themes generated from focus narrative interviews are described. These themes are: willingness of mothers to breastfeed and continue, management of breastfeeding, use of pacifier, daily life, ınstructions of healthcare personnel, and advices from practice of experienced mothers. This study showed that women were aware of the importance of mother's milk for their babies. They all, somehow, made intensive efforts to breastfeed their twins. Women who expect and/or have multiple babies need much more support and guidance, which may include advice for nutritional and daily care. PMID:24592592

  17. Atypical parasitic ischiopagus conjoined twins.

    PubMed

    Corona-Rivera, J Román; Corona-Rivera, Enrique; Franco-Topete, Ramón; Acosta-León, Jorge; Aguila-Dueñas, Virginia; Corona-Rivera, Alfredo

    2003-02-01

    Occurrence of asymmetrical or parasitic conjoined twins (CT) is rare, and currently they are classified analogically to the common unions of symmetrical CT. The authors report on an infant with a parasitic third limb attached to the left lateral aspect of the autosite trunk, in whom male gonadal tissue was found histologically. Parasite parts included complete left lower limb, hemipelvis, lumbosacral vertebral column, spinal cord, and one kidney with ureter and adrenal gland. Autosite anomalies comprised a small left diaphragmatic defect, omphalocele, exstrophy of cloaca, and lumbar meningomyelocele. The authors considered this case to be a rare atypical parasitic ischiopagus CT. The differential diagnosis of the type of twining and other entities with caudal duplications is analyzed briefly.

  18. Effects of twin gestation on maternal morbidity.

    PubMed

    Young, Brett C; Wylie, Blair J

    2012-06-01

    As the incidence of twin gestation increases, it is important to consider the maternal risks associated with carrying multiples. Compared with singleton gestation, there are increased risks to the mother during the antepartum, intrapartum, and postpartum periods. Certain pregnancy complications are more likely to occur during a twin gestation, including preeclampsia and other hypertensive disorders, antepartum hospitalization for preterm labor or abnormal bleeding, nutritional deficiencies, cesarean delivery, and postpartum hemorrhage. Women carrying twins may benefit from early education regarding these issues, close maternal monitoring as well as physical therapy sessions, and nutrition counseling during their pregnancies.

  19. Intravenous nutrition during a twin pregnancy.

    PubMed

    Karamatsu, J T; Boyd, A T; Cooke, J; Vinall, P S; McMahon, M J

    1987-01-01

    A case is reported of a woman in the third trimester of a twin pregnancy who required intravenous nutrition because of inadequate absorption of nutrients due to a jejunoileal bypass. Weight gain was poor, and there was evidence of intrauterine growth retardation before commencement of intravenous feeding. She received overnight intravenous nutrition for 6 weeks and gained weight with ultrasound evidence of fetal growth. During the 33rd week of gestation, she was delivered of healthy twin males who were at appropriate birth weights and development for their age of gestation. The considerations in intravenous nutrition for a twin pregnancy after jejunoileal bypass are discussed.

  20. New growth mode through decorated twin boundaries.

    PubMed

    Bleikamp, Sebastian; Thoma, Arne; Polop, Celia; Pirug, Gerhard; Linke, Udo; Michely, Thomas

    2006-03-24

    Scanning tunneling microscopy and low energy electron diffraction were used to investigate the growth of partly twinned Ir thin films on Ir(111). A transition from the expected layer-by-layer to a defect dominated growth mode with a fixed lateral length scale and increasing roughness is observed. During growth, the majority of the film is stably transformed to twinned stacking. This transition is initiated by the energetic avoidance of the formation of intrinsic stacking faults compared to two independent twin faults. The atomistic details of the defect kinetics are outlined.

  1. A Proper Perspective on the Twin Deficits

    DTIC Science & Technology

    1989-05-01

    the deficits may be imprudent. It would not be a disaster. Moreover, focusing on the deficits diverts attention from the economy’s more significant...toIC TILE Q tN I A PRlOPE l PERSPECTIVE ON THE TWIN DEFICITS Charles Wolf, Jr. May 1989 DTIC LECT I P-7565 • " ’ " ’ , v pcbc MwI I The RAND...Monies, CA 90406-2138 A PROPER PERSPECTIVE ON THE TWIN DEFICITS [1] by Charles Wolf, Jr. While it’s true that the deficit twins -- the budget deficit and

  2. THE RELATIONSHIP BETWEEN BIRTH WEIGHT AND HYPODONTIA IN TWINS,

    DTIC Science & Technology

    The relationship between birth weight and congenitally missing teeth (hypodontia) was investigated in 262 twins from the naval recruit population... birth weight 5.5 pounds or less). Hypodontia frequency was higher in ’premature’ twins than in twins with birth weight over 5.5 pound. Mean birth weight was...number variability in twins. The increased frequency of hypodontia in twins and the low birth weight -hypodontia relationship suggest that prenatal

  3. 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

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

    SciTech Connect

    Wu, Wei; Gao, Yanfei; Li, Nan; Parish, Chad M.; Liu, Wenjun; Liaw, Peter K.; An, Ke

    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 calculation 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.

  5. Prevention of preterm delivery in twin pregnancy.

    PubMed

    Rode, Line; Tabor, Ann

    2014-02-01

    The incidence of twin gestation has increased markedly over the past decades, mostly because of increased use of assisted reproductive technologies. Twin pregnancies are at increased risk of preterm delivery (i.e. birth before 37 weeks of gestation). Multiple gestations therefore account for 2-3% of all pregnancies but constitute at least 10% of cases of preterm delivery. Complications from preterm birth are not limited to the neonatal period, such as in retinopathy of prematurity, intraventricular haemorrhage, necrotising enterocolitis, respiratory disorder and sepsis; they can also constitute sequelae such as abnormal neurophysiological development in early childhood and underachievement in school. Several treatment modalities have been proposed in singleton high-risk pregnancies. The mechanism of initiating labour may, however, be different in singleton and twin gestations. Therefore, it is mandatory to evaluate the proposed treatments in randomised trials of multiple gestations. In this chapter, we describe the results of trials to prevent preterm delivery in twin pregnancies.

  6. Twin Studies: A Unique Epidemiological Tool

    PubMed Central

    Sahu, Monalisha; Prasuna, Josyula G

    2016-01-01

    Twin studies are a special type of epidemiological studies designed to measure the contribution of genetics as opposed to the environment, to a given trait. Despite the facts that the classical twin studies are still being guided by assumptions made back in the 1920s and that the inherent limitation lies in the study design itself, the results suggested by earlier twin studies have often been confirmed by molecular genetic studies later. Use of twin registries and various innovative yet complex software packages such as the (SAS) and their extensions (e.g., SAS PROC GENMOD and SAS PROC PHREG) has increased the potential of this epidemiological tool toward contributing significantly to the field of genetics and other life sciences. PMID:27385869

  7. Breast-Feeding Twins: Making Feedings Manageable

    MedlinePlus

    ... breast-feed more than one baby? Here's help breast-feeding twins or other multiples, from getting positioned and ensuring an adequate milk supply to combining breast-feeding and formula-feeding. By Mayo Clinic Staff If ...

  8. Shock Driven Twinning in Tantalum Single Crystals

    SciTech Connect

    McNaney, J M; HSUING, L M; Barton, N R; Kumar, M

    2009-07-20

    Recovery based observations of high pressure material behavior generated under high explosively driven flyer based loading conditions are reported. Two shock pressures, 25, and 55 GPa and four orientations {l_brace}(100), (110), (111), (123){r_brace} were considered. Recovered material was characterized using electron backscatter diffraction along with a limited amount of transmission electron microscopy to assess the occurrence of twinning under each test condition. Material recovered from 25 GPa had a very small fraction of twinning for the (100), (110), and (111) oriented crystals while a more noticeable fraction of the (123) oriented crystal was twinned. Material recovered from 55 GPa showed little twinning for (100) orientation slightly more for the (111) orientation and a large area fraction for the (123) orientation. The EBSD and TEM observations of the underlying deformation substructure are rationalized by comparing with previous static and dynamic results.

  9. [6 cases of toxoplasmosis in twins].

    PubMed

    Couvreur, J; Thulliez, T; Daffos, F; Aufrant, C; Bompard, Y; Goumy, P; Tournier, G

    1991-02-01

    Studies of congenital toxoplasmosis in twins confirm the definite role of the placenta in the modalities and mechanism of fetal contamination. In single-chorion twin pregnancies, clinical manifestations are generally identical in both infants. Conversely, twins from double-chorion pregnancies usually have different clinical patterns; occasionally, only one of the twins is affected (1 case). The diagnosis can be ascertained antenatally by sampling blood from each of the fetuses (2 cases). The cases reported herein illustrate some of the diagnostic pitfalls that may lead to inappropriate discontinuation of monitoring and treatment: negative placental studies, absence of specific IgM antibodies, transient fall in IgG antibody titers, delayed fetal contamination after a negative fetal blood study, and need for routine tests for increased CSF albumin levels.

  10. Asymmetric twins in rhombohedral boron carbide

    SciTech Connect

    Fujita, Takeshi Guan, Pengfei; Madhav Reddy, K.; Hirata, Akihiko; Guo, Junjie; Chen, Mingwei

    2014-01-13

    Superhard materials consisting of light elements have recently received considerable attention because of their ultrahigh specific strength for a wide range of applications as structural and functional materials. However, the failure mechanisms of these materials subjected to high stresses and dynamic loading remain to be poorly known. We report asymmetric twins in a complex compound, boron carbide (B{sub 4}C), characterized by spherical-aberration-corrected transmission electron microscopy. The atomic structure of boron-rich icosahedra at rhombohedral vertices and cross-linked carbon-rich atomic chains can be clearly visualized, which reveals unusual asymmetric twins with detectable strains along the twin interfaces. This study offers atomic insights into the structure of twins in a complex material and has important implications in understanding the planar defect-related failure of superhard materials under high stresses and shock loading.

  11. Severe Anisometropic Myopia in Identical Twins

    PubMed Central

    Adenuga, Olukorede O.

    2014-01-01

    High anisometropic myopia is a rare condition in twins. Genetic factors have been implicated in its development and there may be an association with vision-threatening complications. A pair of 11-year-old twins presented with poor distance vision in both eyes. Detailed ocular examination was performed including slit lamp examination, dilated funduscopy, cycloplegic refraction, keratometry and axial length measurement. The objective refraction was -6.50DS -2.00DC × 180 (right eye), -1.00DS (left eye) for the first twin; -13.75DS -2.25DC × 180 (right eye), -0.50DS -0.75DC × 04 (left eye) for the second twin. This case suggests an underlying genetic defect in the development of myopia. PMID:25100917

  12. Temporal ghost imaging with twin photons

    NASA Astrophysics Data System (ADS)

    Denis, Séverine; Moreau, Paul-Antoine; Devaux, Fabrice; Lantz, Eric

    2017-03-01

    We use twin photons generated by spontaneous parametric down conversion to perform temporal ghost imaging of a single time signal. The retrieval of a binary signal containing eight bits is performed with an error rate below 1%.

  13. Last Flight for GRAIL's Twin Spacecraft

    NASA Video Gallery

    This animation shows the final flight path for NASA’s twin GravityRecovery and Interior Laboratory (GRAIL) mission spacecraft, which willimpact the moon on Dec. 17, 2012, around 2:28 p.m. PST. ...

  14. 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.

  15. Screening and Invasive Testing in Twins

    PubMed Central

    Monni, Giovanni; Iuculano, Ambra; Zoppi, Maria Angelica

    2014-01-01

    Prenatal screening and testing for trisomy 21 in twin pregnancies poses a number of challenges: the exact estimate of the a priori risk of trisomy 21, the choice of prenatal screening test and/or invasive techniques to employ for the diagnosis and the impact of the result on the options of treatment in case of discordant results within a twin pair or among multiples. These different aspects are discussed below while recognizing that many issues remain unresolved. PMID:26237482

  16. Twin pregnancy in the congenital malformed uterus.

    PubMed

    Heinonen, Pentti K

    2016-07-01

    The frequency and outcome of twin pregnancies in women with uterine malformation were studied. The cohort comprised 13 (4.9%) women with twin pregnancy found among 263 women. They had 483 deliveries, 13 of them twins (2.7%; 95% CI 1.6-4.6%). Among 38 patients with unicornuate uterus 5 (6.8%) out of 74 deliveries were twins, 39 women with didelphic uterus 2 (3.2%) out of 62 deliveries and 147 women with septate or subseptate uterus 6 (2.3%) out of 264 deliveries were twins. The mean duration of gestation was 249 days (range 190-268 days), 5 (38%) out of 13 deliveries were premature, 25 out of 26 newborns were alive. Mean durations of gestation and mean weights of newborns did not differ when 7 cases with unicornuate or didelphic uterus were compared to 6 cases with complete or partial uterine septum. A congenital malformed uterus can bear twin pregnancy without severe complications apart from prematurity.

  17. 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.

  18. Aeroacoustic Experiments with Twin Jets

    NASA Technical Reports Server (NTRS)

    Bozak, Richard F.; Henderson, Brenda S.

    2012-01-01

    While the noise produced by a single jet is azimuthally symmetric, multiple jets produce azimuthally varying far-field noise. The ability of one jet to shield another reduces the noise radiated in the plane of the jets, while often increasing the noise radiated out of the plane containing the jets. The present study investigates the shielding potential of twin jet configurations over subsonic and over-expanded supersonic jet conditions with simulated forward flight. The experiments were conducted with 2 in. throat diameter nozzles at four jet spacings from 2.6d to 5.5d in center-to-center distance, where d is the nozzle throat diameter. The current study found a maximum of 3 dB reduction in overall sound pressure level relative to two incoherent jets in the peak jet noise direction in the plane containing the jets. However, an increase of 3 dB was found perpendicular to the plane containing the jets. In the sideline direction, shielding is observed for all jet spacings in this study.

  19. Niobium and tantalum: indispensable twins

    USGS Publications Warehouse

    Schulz, Klaus; Papp, John

    2014-01-01

    Niobium and tantalum are transition metals almost always paired together in nature. These “twins” are difficult to separate because of their shared physical and chemical properties. In 1801, English chemist Charles Hatchett uncovered an unknown element in a mineral sample of columbite; John Winthrop found the sample in a Massachusetts mine and sent it to the British Museum in London in 1734. The name columbium, which Hatchet named the new element, came from the poetic name for North America—Columbia—and was used interchangeably for niobium until 1949, when the name niobium became official. Swedish scientist Anders Ekberg discovered tantalum in 1802, but it was confused with niobium, because of their twinned properties, until 1864, when it was recognized as a separate element. Niobium is a lustrous, gray, ductile metal with a high melting point, relatively low density, and superconductor properties. Tantalum is a dark blue-gray, dense, ductile, very hard, and easily fabricated metal. It is highly conductive to heat and electricity and renowned for its resistance to acidic corrosion. These special properties determine their primary uses and make niobium and tantalum indispensable.

  20. Situs Inversus Totalis in Twins: A Brief Review and a Life History / Twin Research: Twin Studies of Trisomy 21; Monozygotic Twin Concordance for Bilateral Coronoid Hyperplasia; Prenatal Hormonal Effects in Mixed-Sex Non-Human Primate Litters; Insurance Mandates and Twinning After In Vitro Fertilization / News Reports: First Report of Identical Twin Puppies; Twins Sisters Turn 100; Remembering an Identical Twin Production Designer; New York City Marathon Quadruplets.

    PubMed

    Segal, Nancy L

    2017-02-01

    The presence of situs inversus totalis (full reversal of internal organs) in twins is briefly reviewed. Information gathered from 35-year-old monozygotic (MZ) female twin pair discordant for this condition is presented. This is followed by summaries of research on the frequency of trisomy 21 (Down syndrome) in twins, the first case of MZ twin concordance for bilateral coronoid hyperplasia, prenatal hormonal effects in mixed-sex non-human primate litters, and links between insurance mandates and twinning following in vitro fertilization. The final section of this article describes twin-related events reported in the news, namely, the first recorded birth of identical twin puppies; the 100th birthday celebration of a pair of fraternal female twins, the passing of an award-winning identical twin production designer, and the first running of the New York City Marathon by a set of quadruplets.

  1. Deformation twinning mechanisms in FCC and HCP metals

    SciTech Connect

    Wang, Jian; Tome, Carlos N; Beyerlein, Irene J; Misra, Amit; Mara, N

    2011-01-31

    We report the recent work on twinning and detwinning in fcc and hcp metals based on the in situ and ex situ TEM observations and molecular dynamics simulations. Three aspects are discussed in this paper. (1) Detwinning in single-phase Cu with respect to growth twins, (2) deformation twinning in Ag-Cu composites, and (3) deformation twinning mechanisms in hcp metals. The main conclusion is that atomic structures of interfaces (twin boundaries, two-phases interface, and grain boundaries) play a crucial role in nucleating and propagating of deformation twins.

  2. Twin studies in auto-immune disease.

    PubMed

    Leslie, R D; Hawa, M

    1994-01-01

    Immune-mediated diseases affect up to 5% of the population and are a major cause of morbidity and mortality. These diseases can be organ specific, such as insulin-dependent diabetes (IDDM) and non-organ specific, such as Rheumatoid Arthritis (RA). Identical and non-identical twins have been used to establish whether these diseases are determined by genetic or environmental factors. The results of these studies have been collated in a new section of the Mendel Institute in Rome. Diseases included in these studies included IDDM, RA, Systemic Lupus Erythematosus (SLE), Multiple Sclerosis (MS) and Myasthenia. Striking differences in concordance rates between identical and non-identical twins in all these studies suggest that genetic factors are important in causing these diseases. All the diseases are known to be associated with HLA genes on chromosome 6 which may account for some or all of the genetic susceptibility. However, in the majority of pairs the affected twin has an unaffected co-twin. These observations suggest that non-genetically determined factors, probably environmental factors and not somatic mutations, are critical. The study of unaffected co-twins, who are at high disease-risk, has allowed the identification of changes which precede and predict the clinical disease. The immune-mediated destruction in many of these diseases is probably caused by T-lymphocytes. Twin studies have shown the importance of genetic factors in determining T-cell responses. Identical twins should, therefore, provide the perfect test bed to assess the role of T-cells in immune-mediated diseases.

  3. The Project TALENT Twin and Sibling Study.

    PubMed

    Prescott, Carol A; Achorn, Deanna Lyter; Kaiser, Ashley; Mitchell, Lindsey; McArdle, John J; Lapham, Susan J

    2013-02-01

    Project TALENT is a US national longitudinal study of about 377,000 individuals born in 1942-1946, first assessed in 1960. Students in about 1,200 schools participated in a 2-day battery covering aptitudes, abilities, interests, and individual and family characteristics (Flanagan, 1962; www.projectTALENT.org). Follow-up assessments 1, 5, and 11 years later assessed educational and occupational outcomes. The sample includes approximately 92,000 siblings from 40,000 families, including 2,500 twin pairs and 1,200 other siblings of twins. Until recently, almost no behavior genetic research has been conducted with the sample. In the original data collection information was not collected with the intent to link family members. Recently, we developed algorithms using names, addresses, birthdates, and information about family structure to link siblings and identify twins. We are testing several methods to determine zygosity, including use of yearbook photographs. In this paper, we summarize the design and measures in Project TALENT, describe the Twin and Sibling sample, and present our twin-sib-classmate model. In most twin and family designs, the 'shared environment' includes factors specific to the family combined with between-family differences associated with macro-level variables such as socioeconomic status. The school-based sampling design used in Project TALENT provides a unique opportunity to partition the shared environment into variation shared by siblings, specific to twins, and associated with school- and community-level factors. The availability of many measured characteristics on the family, schools, and neighborhoods enhances the ability to study the impact of specific factors on behavioral variation.

  4. Characterization of Gastric Microbiota in Twins.

    PubMed

    Dong, Quanjiang; Xin, Yongning; Wang, Lili; Meng, Xinying; Yu, Xinjuan; Lu, Linlin; Xuan, Shiying

    2017-02-01

    Contribution of host genetic backgrounds in the development of gastric microbiota has not been clearly defined. This study was aimed to characterize the biodiversity, structure and composition of gastric microbiota among twins. A total of four pairs of twins and eight unrelated individuals were enrolled in the study. Antral biopsies were obtained during endoscopy. The bacterial 16S rRNA gene was amplified and pyrosequenced. Sequences were analyzed for the composition, structure, and α and β diversities of gastric microbiota. Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Fusobacteria were the most predominant phyla of gastric microbiota. Each individual, twins as well as unrelated individuals, harbored a microbiota of distinct composition. There was no evidence of additional similarity in the richness and evenness of gastric microbiota among co-twins as compared to unrelated individuals. Calculations of θYC and PCoA demonstrated that the structure similarity of gastric microbial community between co-twins did not increase compared to unrelated individuals. In contrast, the structure of microbiota was altered enormously by Helicobacter pylori infection. These results suggest that host genetic backgrounds had little effect in shaping the gastric microbiota. This property of gastric microbiota could facilitate the studies discerning the role of microbiota from genetic grounds in the pathogenesis.

  5. Psychological Distress in Twins with Urological Symptoms

    PubMed Central

    Wright, Lisa Johnson; Noonan, Carolyn; Ahumada, Sandra; Rodríguez, María Ángeles Bullones; Buchwald, Dedra; Afari, Niloofar

    2010-01-01

    Objective Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic pain condition with unclear underlying etiology. Our objectives were to determine if psychological distress was higher in twins with urological symptoms commonly found in IC/PBS than twins without, and if so, did familial influences contribute to this association. Method Data from 1,165 female twins in a community-based sample were used. Urological symptoms, symptoms of posttraumatic stress disorder (PTSD), depression, anxiety, and perceived stress were assessed with standardized questionnaires. Generalized estimating equation regression models were used to examine the relationship between psychological distress and urological symptoms. Results Compared to unaffected twins, twins with urological symptoms were more likely to report PTSD symptoms (OR = 3.9; CI = 2.6-5.8), depression (OR = 3.1; CI = 2.0-5.0), anxiety (OR = 3.4; CI = 2.3-5.2), and perceived stress (OR = 3.2; CI = 2.1-4.9). After adjusting for familial influences, the within-pair effects remained significant for PTSD symptoms (OR = 2.2; CI = 1.2-3.8) and perceived stress (OR = 2.2; CI = 1.2-3.8). Conclusion Familial influences partially explained the relationship between indicators of psychological distress and urological symptoms. Future research should examine shared environmental and genetic mechanisms that may further explain this relationship and improve diagnosis and treatment of this unexplained clinical condition. PMID:20430229

  6. NAE Twin Otter operations in FIFE 1989

    NASA Technical Reports Server (NTRS)

    Macpherson, J. I.

    1990-01-01

    During the summer of 1989, the National Aeronautical Establishment (Canada) Twin Otter Atmospheric Research Aircraft was flow in support of the NASA sponsored First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment called FIFE-89. Airborne measurements of the fluxes of heat, momentum, water vapor and carbon dioxide were made during 16 flow-altitude flights over the FIFE project area in central Kansas. The Twin Otter operations in FIFE are documented and details are included on the instrumentation, software, flight procedures, atmospheric conditions and analysis methods. Comparisons of Twin Otter measured fluxes are made with those determined at several surface sites and with those made by other instrumented aircraft in the FIFE-87 measurements. Airborne flux measurements are related to run length, altitude, and environmental parameters such as vegetation type, temperature, and wind speed. One night flight was run in an attempt to measure the respiration component of the CO2 flux. The use of aircraft was studied for regional observations of fluxes and to relate these to satellite radiance measurements. Run average data are presented for all 285 flux runs flown by the Twin Otter in FIFE-89. This should serve as as a working reference for scientists utilizing Twin Otter data either directly of through the FIFE data archive.

  7. The Onsala Twin Telescope Project

    NASA Astrophysics Data System (ADS)

    Haas, R.

    2013-08-01

    This paper described the Onsala Twin Telescope project. The project aims at the construction of two new radio telescopes at the Onsala Space Observatory, following the VLBI2010 concept. The project starts in 2013 and is expected to be finalized within 4 years. Z% O. Rydbeck. Chalmers Tekniska Högskola, Göteborg, ISBN 91-7032-621-5, 407-823, 1991. B. Petrachenko, A. Niell, D. Behrend, B. Corey, J. Böhm, P. Charlot, A. Collioud, J. Gipson, R. Haas, Th. Hobiger, Y. Koyama, D. MacMillan, Z. Malkin, T. Nilsson, A. Pany, G. Tuccari, A. Whitney, and J. Wresnik. Design Aspects of the VLBI2010 System. NASA/TM-2009-214180, 58 pp., 2009. R. Haas, G. Elgered, J. Löfgren, T. Ning, and H.-G. Scherneck. Onsala Space Observatory - IVS Network Station. In K. D. Baver and D. Behrend, editors, International VLBI Service for Geodesy and Astrometry 2011 Annual Report, NASA/TP-2012-217505, 88-91, 2012. H.-G. Scherneck, G. Elgered, J. M. Johansson, and B. O. Rönnäng. Phys. Chem. Earth, Vol. 23, No. 7-8, 811-823, 1998. A. R. Whitney. Ph.D. thesis, Dept. of Electrical engineering, MIT Cambridge, MA., 1974. B. A. Harper, J. D. Kepert, and J. D. Ginger. Guidelines for converting between various wind averaging periods in tropical cyclone conditions. WMO/TD-No. 1555, 64 pp., 2010 (available at \\url{http://www.wmo.int/pages/prog/www/tcp/documents/WMO_TD_1555_en.pdf})

  8. Quantifying the heritability of task-related brain activation and performance during the N-back working memory task: A twin fMRI study

    PubMed Central

    Blokland, Gabriëlla A.M.; McMahon, Katie L.; Hoffman, Jan; Zhu, Gu; Meredith, Matthew; Martin, Nicholas G.; Thompson, Paul M.; de Zubicaray, Greig I.; Wright, Margaret J.

    2008-01-01

    Working memory-related brain activation has been widely studied, and impaired activation patterns have been reported for several psychiatric disorders. We investigated whether variation in N-back working memory brain activation is genetically influenced in 60 pairs of twins, (29 monozygotic (MZ), 31 dizygotic (DZ); mean age 24.4 ± 1.7S.D.). Task-related brain response (BOLD percent signal difference of 2 minus 0-back) was measured in three regions of interest. Although statistical power was low due to the small sample size, for middle frontal gyrus, angular gyrus, and supramarginal gyrus, the MZ correlations were, in general, approximately twice those of the DZ pairs, with non-significant heritability estimates (14–30%) in the low-moderate range. Task performance was strongly influenced by genes (57–73%) and highly correlated with cognitive ability (0.44–0.55). This study, which will be expanded over the next 3 years, provides the first support that individual variation in working memory-related brain activation is to some extent influenced by genes. PMID:18423837

  9. Somatic and germ-line mosaicism of deletion 15q11.2-q13 in a mother of dyzigotic twins with Angelman syndrome.

    PubMed

    Sánchez, Javier; Fernández, Raquel; Madruga, Marcos; Bernabeu-Wittel, José; Antiñolo, Guillermo; Borrego, Salud

    2014-02-01

    Angelman syndrome (AS, OMIM105830) is a neurogenetic disorder caused by different genetic mechanisms. Determining the genetic mechanism is essential to establish the recurrence risk and the accuracy of genetic/reproductive counseling. The majority of AS patients present with a deletion of the 15q11.2-q13 region on the maternally derived chromosome. The other genetic mechanisms are: paternal disomy of chromosome 15, imprinting center defects, and mutations in the ubiquitin-protein ligase E3A gene (UBE3A). Different recurrence risks are associated with each specific genetic mechanism involved. We report on the study of dizygotic twins with classic phenotypic AS due to deletion of the same maternally derived chromosome 15. The mother presented with hypopigmented macular lesions on the inner side of both arms. Fibroblast culture studies of the maternal hypopigmented skin areas from both arms showed mosaicism for a normal cell line and for a second cell line with a 15q11.2-q13 deletion. This family represents the first demonstrated case of maternal somatic and germ line mosaicism for 15q11.2-q13 deletion as the cause of AS.

  10. 13. TWIN ROCK DITCH AND PIPELINE DITCH HEADING PLAN, ...

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

    13. TWIN ROCK DITCH AND PIPELINE -- DITCH HEADING PLAN, ELEVATION, GABION COURSING & DETAILS - Twin Rock Irrigation Ditch, West bank of Animas River, East of U.S. Highway 550, Bondad, La Plata County, CO

  11. Plasmonic twinned silver nanoparticles with molecular precision

    PubMed Central

    Yang, Huayan; Wang, Yu; Chen, Xi; Zhao, Xiaojing; Gu, Lin; Huang, Huaqi; Yan, Juanzhu; Xu, Chaofa; Li, Gang; Wu, Junchao; Edwards, Alison J.; Dittrich, Birger; Tang, Zichao; Wang, Dongdong; Lehtovaara, Lauri; Häkkinen, Hannu; Zheng, Nanfeng

    2016-01-01

    Determining the structures of nanoparticles at atomic resolution is vital to understand their structure–property correlations. Large metal nanoparticles with core diameter beyond 2 nm have, to date, eluded characterization by single-crystal X-ray analysis. Here we report the chemical syntheses and structures of two giant thiolated Ag nanoparticles containing 136 and 374 Ag atoms (that is, up to 3 nm core diameter). As the largest thiolated metal nanoparticles crystallographically determined so far, these Ag nanoparticles enter the truly metallic regime with the emergence of surface plasmon resonance. As miniatures of fivefold twinned nanostructures, these structures demonstrate a subtle distortion within fivefold twinned nanostructures of face-centred cubic metals. The Ag nanoparticles reported in this work serve as excellent models to understand the detailed structure distortion within twinned metal nanostructures and also how silver nanoparticles can span from the molecular to the metallic regime. PMID:27611564

  12. Plasmonic twinned silver nanoparticles with molecular precision

    NASA Astrophysics Data System (ADS)

    Yang, Huayan; Wang, Yu; Chen, Xi; Zhao, Xiaojing; Gu, Lin; Huang, Huaqi; Yan, Juanzhu; Xu, Chaofa; Li, Gang; Wu, Junchao; Edwards, Alison J.; Dittrich, Birger; Tang, Zichao; Wang, Dongdong; Lehtovaara, Lauri; Häkkinen, Hannu; Zheng, Nanfeng

    2016-09-01

    Determining the structures of nanoparticles at atomic resolution is vital to understand their structure-property correlations. Large metal nanoparticles with core diameter beyond 2 nm have, to date, eluded characterization by single-crystal X-ray analysis. Here we report the chemical syntheses and structures of two giant thiolated Ag nanoparticles containing 136 and 374 Ag atoms (that is, up to 3 nm core diameter). As the largest thiolated metal nanoparticles crystallographically determined so far, these Ag nanoparticles enter the truly metallic regime with the emergence of surface plasmon resonance. As miniatures of fivefold twinned nanostructures, these structures demonstrate a subtle distortion within fivefold twinned nanostructures of face-centred cubic metals. The Ag nanoparticles reported in this work serve as excellent models to understand the detailed structure distortion within twinned metal nanostructures and also how silver nanoparticles can span from the molecular to the metallic regime.

  13. Aging and communication in the twin paradox

    NASA Astrophysics Data System (ADS)

    de Wolf, David A.

    2016-11-01

    The twin paradox of the special theory of relativity has given rize to a large body of literature discussing its implications. In its standard form, the traveler changes velocity only at the destination of the trip, so that he appears to perceive an improbably instantaneous and non-continuous change in age of the stationary twin. In this work, a smooth velocity/acceleration profile is used that allows the abrupt velocity-change case as a limit. All gravitational effects are ignored in this treatment. Aside from mutual perception of simultaneous clock times in an accelerating frame, constant communication of clock times between the twins by means of (digital) light signals is shown to be possible, in principle if not in practice.

  14. Stability of ideal fcc twin boundaries

    NASA Astrophysics Data System (ADS)

    Wright, T. W.; Daphalapurkar, N. P.; Ramesh, K. T.

    2014-12-01

    Ideas from continuum mechanics are used to derive an elastic stability inequality for a boundary between two different materials under quasi-static, homogeneous conditions. The terms in this inequality are interpreted for the case of an ideal twinning plane between two variants of a face-centered cubic material. High quality potentials for Ni and Cu are used in molecular dynamics calculations to calibrate relevant energies and displacements near the twinning plane. It is found that in comparison with direct molecular dynamics calculations the inequality predicts the critical stress that initiates movement of the twinning plane in Ni within 1.9% and within 1.3% for Cu. Although the predicted and calculated critical stresses are only upper bounds for the more realistic case of an imperfect boundary, the calculations give considerable insight into the interplay of energies that lead to boundary motion.

  15. Twinning-mediated formability in Mg alloys

    PubMed Central

    Suh, Byeong-Chan; Kim, Jae H.; Hwang, Ji Hyun; Shim, Myeong-Shik; Kim, Nack J.

    2016-01-01

    Mg alloys are promising candidates for automotive applications due to their low density and high specific strength. However, their widespread applications have not been realized mainly because of poor formability at room temperature, arising from limited number of active deformation systems and strong basal texture. It has been recently shown that Mg-Zn-Ca alloys have excellent stretch formability, which has been ascribed to their weak basal texture. However, the distribution of basal poles is orthotropic, which might result in anisotropy during deformation and have adverse effect on formability. Here, we show that tension twinning is mainly responsible for enhanced formability of Mg-Zn-Ca alloys. We found that tension twinning is quite active during both uniaxial deformation and biaxial deformation of Mg-Zn-Ca alloy even under the stress conditions unfavourable for the formation of tensile twins. Our results provide new insights into the development of Mg alloys having high formability. PMID:26926655

  16. Twinning-mediated formability in Mg alloys.

    PubMed

    Suh, Byeong-Chan; Kim, Jae H; Hwang, Ji Hyun; Shim, Myeong-Shik; Kim, Nack J

    2016-03-01

    Mg alloys are promising candidates for automotive applications due to their low density and high specific strength. However, their widespread applications have not been realized mainly because of poor formability at room temperature, arising from limited number of active deformation systems and strong basal texture. It has been recently shown that Mg-Zn-Ca alloys have excellent stretch formability, which has been ascribed to their weak basal texture. However, the distribution of basal poles is orthotropic, which might result in anisotropy during deformation and have adverse effect on formability. Here, we show that tension twinning is mainly responsible for enhanced formability of Mg-Zn-Ca alloys. We found that tension twinning is quite active during both uniaxial deformation and biaxial deformation of Mg-Zn-Ca alloy even under the stress conditions unfavourable for the formation of tensile twins. Our results provide new insights into the development of Mg alloys having high formability.

  17. Estimation of penetrance from twin data.

    PubMed

    Praxedes, L A; Otto, P A

    2000-12-01

    A simple method for estimating the gene frequency p and the penetrance value K from data on polymorphic monogenic characteristics on monozygotic twin pairs is presented. In spite of the method here presented having limited value because the results it yields cannot be evaluated on their own, the estimates of p and K it provides can be indirectly tested by comparing them to the ones obtained in familial aggregates through classical segregation analysis or by using the latter to calculate the expected proportions of dominant-dominant, dominant-recessive and recessive-recessive monozygotic twin pairs. When the method is applied to data on tongue-rolling ability published in the literature, a good agreement is observed between twin and familial estimates, thus indicating that the method is reliable and that it can be used as an ancillary way of corroborating or otherwise evidence of monogenic autosomal dominant mechanism inferred from the analysis of familial data.

  18. TWSVR: Regression via Twin Support Vector Machine.

    PubMed

    Khemchandani, Reshma; Goyal, Keshav; Chandra, Suresh

    2016-02-01

    Taking motivation from Twin Support Vector Machine (TWSVM) formulation, Peng (2010) attempted to propose Twin Support Vector Regression (TSVR) where the regressor is obtained via solving a pair of quadratic programming problems (QPPs). In this paper we argue that TSVR formulation is not in the true spirit of TWSVM. Further, taking motivation from Bi and Bennett (2003), we propose an alternative approach to find a formulation for Twin Support Vector Regression (TWSVR) which is in the true spirit of TWSVM. We show that our proposed TWSVR can be derived from TWSVM for an appropriately constructed classification problem. To check the efficacy of our proposed TWSVR we compare its performance with TSVR and classical Support Vector Regression(SVR) on various regression datasets.

  19. Longitudinal research on temperament in twins.

    PubMed

    Torgersen, A M

    1987-01-01

    The changing influence of genetic factors of temperamental individuality has been studied longitudinally in a group of 44 same-sexed twin pairs at four different ages from infancy to puberty. Previous results showed that genetic factors seemed to play an important role in the development of temperamental characteristics when the twins were in infancy and at six years of age. The present report shows that when the within-pair differences in temperament are studied again at age 15 years, the similarity of identical pairs is even higher than at earlier ages. When shared and nonshared stress in the twin pairs was assessed at this age, some interactions were found between within-pair differences in temperament, stress and zygosity.

  20. Twins and politics: political careers and political attitudes / twin research reviews: pair-bonding; facial expressivity in reared apart twins; educating multiples / stories that move and amaze us: a military funeral; a twins' reunion; Egyptian septuplets; rare occupations.

    PubMed

    Segal, Nancy L

    2008-12-01

    Twins and twin research are providing fresh insights into the roots of political behavior. This topic is approached from dual perspectives: why some individuals choose to become politicians, and why individuals vary in their political attitudes and interests. Reviews of timely twin studies in the areas of pair-bonding, facial expressivity and education follow. Finally, some extraordinary events in the lives of twins and their families are revealed.

  1. The twin paradox in the presence of gravity

    NASA Astrophysics Data System (ADS)

    Gasperini, M.

    2014-09-01

    Conventional wisdom, based on kinematic (flat-space) intuition, tell us that a static twin is aging faster than his traveling twin brother. However, such a situation could be exactly inverted if the two twins are embedded in an external gravitational field, and if the (dynamical) distortion of the spacetime geometry, due to gravity, is strong enough to compensate the kinematic effect of the relative twin motion.

  2. [A case of twins with probable superfetation (author's transl)].

    PubMed

    Bertrams, J; Preuss, H

    1980-01-01

    A twin case of disputed paternity with probable superfetation is reported. The putative father could be excluded as the father of Twin F by HLA, GLO, and Ss typing results, but could not be excluded as the father of Twin S, with a probability of paternity for this twin of 99.995%. A birth weight difference of 450 g and the evidence for additional sexual intercourses by the mother suggest the very rare event of a superfetation.

  3. Psychological adjustment to twins after infertility.

    PubMed

    Klock, Susan C

    2004-08-01

    The birth of twins and other multiples is physically and emotionally stressful. The increase in the use of the assisted reproductive technologies has lead to an exponential increase in the rates of twins and triplets in the US. Whereas the medical complications of twins and other multiples has been well studied, the psychological and social implications of these events has not. Very little empirical research has been conducted to assess the differential impact of twins, as compared to singletons, on maternal adjustment, postpartum depression and marital functioning. In addition, assessment of infant health, disposition and behavior and its relation to maternal adjustment is lacking. The birth of twins after a period of infertility complicates the clinical picture and the impact of infertility on subsequent parental adjustment is only beginning to be understood. Although research suggests that infertile couples often desire multiples, the experience of parenting multiples after infertility has not been studied. Research on fertile couples indicate that: (i) approximately 10% of women develop postpartum depression and; (ii) marital adjustment declines after the birth of the first child. Because of the unique demands of parenting multiples, it is hypothesized that mothers of twins who have a history of infertility would be at increased risk for depression and marital decline. Descriptive studies of these families support this view, although additional studies are needed to determine the degree and extent of the problem. Additionally, variables such as, prepregnancy adjustment, equitable division of child-care tasks and perceived social support should be studied to determine if they buffer against the expected effects.

  4. Twin heart with a fused atria and separate ventricles in conjoined twins

    PubMed Central

    Ambar, Sameer Suresh; Halkati, Prabhu C; Patted, Suresh V; Yavagal, ST

    2010-01-01

    One of the most interesting congenital malformations is that of conjoined twins. We report echocardiographic features of twin heart in dicephalus, tribrachius, dispinous, thoracoomphalopagus twin. It showed two hearts fused at atrial level. Right-sided heart had single atrial chamber with a single ventricle. A single great vessel, aorta, originated from it. Left-sided heart was well developed with two atria and two ventricles. There was a small mid muscular ventricular septal defect and a small patent ductus arteriosus. Great arteries had normal origins. PMID:21234207

  5. 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.

  6. Conjoined twins: scientific cinema and Pavlovian physiology.

    PubMed

    Krementsov, Nikolai

    2015-01-01

    Through the lens of a 1957 documentary film, "Neural and humoral factors in the regulation of bodily functions (research on conjoined twins)," produced by the USSR Academy of Medical Sciences, this essay traces the entwined histories of Soviet physiology, studies of conjoined twins and scientific cinema. It examines the role of Ivan Pavlov and his students, including Leonid Voskresenkii, Dmitrii Fursikov and Petr Anokhin, in the development of "scientific film" as a particular cinematographic genre in Soviet Russia and explores numerous puzzles hidden behind the film's striking visuals.

  7. Partial siamese twin as potential organ donor

    PubMed Central

    Kapoor, Rakesh; Maheshwari, Ruchir; Srivastava, Aneesh; Sharma, Raj K.

    2010-01-01

    During evaluation of a partial Siamese twin for removal of nonviable parasitic part in an 8-year-old male child, a fully functional kidney was found. The functional status of the extra kidney was found to be within acceptable limits for the purpose of transplant, which was subsequently done in a 24-year-old patient with end-stage renal disease. The recipient is healthy 19 months after the surgery. The possibility of using organs from a partial Siamese twin makes this a unique case report. PMID:20877612

  8. Achondroplasia in female twins: surgical indications.

    PubMed

    Albisetti, Walter; Pedretti, Leopoldo; De Bartolomeo, Omar; Verdoni, Fabio; Memeo, Antonio

    2011-03-01

    Although in literature achondroplasia has been described profusely, reports on achondroplastic twins are limited. We present two cases of monozygotic female twins with achondroplasia, who underwent limb-lengthening surgical procedure with external fixation in the following five steps: tibia, femur, tibia; femur, homer. Both the cases presented a good limb length and an optimal correction of associated deformities after the treatment, fulfilling the indications. Surgical indications were mostly led by the axial deviations of the lower limbs, and the timing of the limb-lengthening procedures has been the same in both couples showing the importance of this aspect.

  9. Epicyclic Twin-Helix Ionization Cooling Simulations

    SciTech Connect

    Vasiliy Morozov, Yaroslav Derbenev, A. Afanaciev, R.P. Johnson

    2011-04-01

    Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a highluminosity muon collider. For the implementation of PIC, we earlier developed an epicyclic twin-helix channel with correlated behavior of the horizontal and vertical betatron motions and dispersion. We now insert absorber plates with short energy-recovering units located next to them at the appropriate locations in the twin-helix channel. We first demonstrate conventional ionization cooling in such a system with the optics uncorrelated. We then adjust the correlated optics state and induce a parametric resonance to study ionization cooling under the resonant condition.

  10. Seeing double: annular diaper rash in twins.

    PubMed

    Sommer, Lacy L; Manders, Steven M

    2015-01-01

    We report a case of dichorionic, diamniotic twins who developed similar erythematous, annular, erosive plaques in the inguinal folds in the first few weeks of life that were refractory to topical antifungals and oral antibiotics. The twins were found to have high transaminase levels, antinuclear antibody positivity, and anti-SSS/Ro) and anti-SSB/La autoantibodies. The rash resolved without scarring by 7 months of age with the use of low-potency topical corticosteroids. We suggest that physicians consider neonatal lupus erythematosus in neonates with atypical eruptions occurring in sun-protected skin.

  11. Herceptin (trastuzumab) therapy in a twin pregnancy with associated oligohydramnios.

    PubMed

    Beale, Jennifer M A; Tuohy, Jeremy; McDowell, Simon J

    2009-07-01

    Herceptin (trastuzumab) is an adjuvant chemotherapy agent used in treatment of certain breast cancers. Limited information is available on the use of herceptin in pregnancy. This case is a twin pregnancy exposed to herceptin until 23 weeks' gestation. One twin had chronic renal failure develop, whereas the other twin did not.

  12. Marital Conflict and Conduct Problems in Children of Twins

    ERIC Educational Resources Information Center

    Harden, K. Paige; Turkheimer, Eric; Emery, Robert E.; D'Onofrio, Brian M.; Slutske, Wendy S.; Heath, Andrew C.; Martin, Nicholas G.

    2007-01-01

    The Children-of-Twins design was used to test whether associations between marital conflict frequency and conduct problems can be replicated within the children of discordant twin pairs. A sample of 2,051 children (age 14-39 years) of 1,045 twins was used to estimate the genetic and environmental influences on marital conflict and determine…

  13. MAGNETIC DOMAINS AND TWINNING IN ALPHA-IRON.

    DTIC Science & Technology

    Alpha - iron is another instance of mimetic twinning in which an edifice formed by a group of twinned tetragonal crystals presents an appearance of...cubic symmetry. This confirms earlier suggestions that magnetic domains are crystallographic twins. Crystals of alpha - iron were grown in thin strips of

  14. Hardening by twin boundary during nanoindentation in nanocrystals.

    PubMed

    Qu, Shaoxing; Zhou, Haofei

    2010-08-20

    The atomistic deformation processes of nanocrystals embedded with nanoscale twin boundaries during nanoindentation are studied by molecular dynamics simulations. Load-displacement curves are obtained and the hardening mechanisms associated with the nanoscale twin boundaries are revealed. Johnson's theoretical indentation model is adopted to estimate the elastic stage of the nanoindentation. In addition, twin boundary-mediated dislocation nucleation is observed and analyzed.

  15. A Multivariate Twin Study of Early Literacy in Japanese "Kana"

    ERIC Educational Resources Information Center

    Fujisawa, Keiko K.; Wadsworth, Sally J.; Kakihana, Shinichiro; Olson, Richard K.; DeFries, John C.; Byrne, Brian; Ando, Juko

    2013-01-01

    This first Japanese twin study of early literacy development investigated the extent to which genetic and environmental factors influence individual differences in prereading skills in 238 pairs of twins at 42 months of age. Twin pairs were individually tested on measures of phonological awareness, "kana" letter name/sound knowledge,…

  16. The twin condition and the couple effects on personality development.

    PubMed

    Zazzo, R

    1976-01-01

    Twin psychology has been studied to a very limited extent. Only few remarkable peculiarities of the twins' development are known for sure, such as delayed intellectual development, language retardation with frequent cryptophasia, difficulties and fragility of self consciousness, reduced sociability. These and other peculiarities may result from a number of different factors: biological, peculiar parental attitude, and especially the twin situation itself, the psychology of the twin as an individual being a function of the psychology of the twin pair. Twin peculiarities have for a long time been ignored. On the one hand, psychology ignored the couple reality (it was a "one-body" psychology), and on the other, the twin method classically postulated that twins are not atypical and may therefore be used as a test for the general population. As a matter of fact, twin psychology opens a new way to science. The twin situation may serve as a paradigm for the general study of the couple effect, namely, for the objective analysis of personality as a consequence of the relations between self and others. For certain traits of personality, it is already known that MZ twins brought-up together are significantly less similar than MZ twins brought-up apart. In fact, couple effects may mask or considerably reduce genetic factors.

  17. The association between cannabis abuse and dependence and childhood physical and sexual abuse: Evidence from an offspring of twins design

    PubMed Central

    Duncan, Alexis E.; Sartor, Carolyn E.; Scherrer, Jeffrey F.; Grant, Julia D.; Heath, Andrew C.; Nelson, Elliot C.; Jacob, Theodore; Bucholz, Kathleen Keenan

    2009-01-01

    Aims This study examines the association between childhood physical abuse (CPA) and sexual abuse (CSA) and the development of cannabis abuse and dependence among adolescents and young adults while controlling for genetic and environmental risk factors. Design To control for familial risk differences related to paternal drug dependence that might confound the relationship between CSA and CPA and cannabis abuse/dependence, we created four groups based on father’s and uncle’s substance use dependence (SUD) status reflecting different degrees of genetic and environmental risks to offspring: 1) high genetic, high environmental risk; 2) high genetic, low environmental risk, 3) medium genetic, low environmental risk; and 4) low genetic, low environmental risk. Participants Adolescent and young adult offspring of monozygotic and dizygotic US military veteran twin fathers (n= 819). Measurements Data on CPA and CSA, DSM-IV offspring cannabis abuse/dependence, other SUD and psychopathology, and maternal and paternal SUD and psychopathology were collected via semi-structured telephone interview. Findings Twenty-three percent of the offspring sample met lifetime criteria for cannabis abuse/dependence, 8.55% and 12.82% reported CSA and CPA, respectively. Offspring exposed to CSA, but not CPA, were at significantly greater risk of developing cannabis abuse/dependence compared to those who had not experienced CSA (HR=2.16; 95% CI=1.48–3.16) after controlling for genetic and familial environmental risk and offspring gender, alcohol abuse and dependence and conduct disorder. Conclusions These results indicate that there are effects of CSA on development of cannabis abuse/dependence in addition to the genetic and familial environmental risk imparted by having a drug dependent father. PMID:18482422

  18. A population-based Swedish Twin and Sibling Study of cannabis, stimulant and sedative abuse in men

    PubMed Central

    Kendler, Kenneth S.; Ohlsson, Henrik; Maes, Hermine H.; Sundquist, Kristina; Lichtenstein, Paul; Sundquist, Jan

    2015-01-01

    Background Prior studies, utilizing interview-based assessments, suggest that most of the genetic risk factors for drug abuse (DA) are non-specific with a minority acting specifically on risk for abuse of particular psychoactive substance classes. We seek to replicate these findings using objective national registry data. Methods We examined abuse of cannabis, stimulants (including cocaine) and sedatives ascertained from national Swedish registers in male–male monozygotic (1720 pairs) and dizygotic twins (1219 pairs) combined with near-age full siblings (76,457 pairs) to provide sufficient power. Modeling was performed using Mx. Results A common pathway model fitted better than an independent pathway model. The latent liability to DA was highly heritable but also influenced by shared environment. Cannabis, stimulant and sedative abuse all loaded strongly on the common factor. Estimates for the total heritability for the three forms of substance abuse ranged from 64 to 70%. Between 75 and 90% of that genetic risk was non-specific, coming from the common factor with the remainder deriving from substance specific genetic risk factors. By contrast, all of the shared environmental effects, which accounted for 18–20% of the variance in liability, were non-specific. Conclusions In accord with prior studies based on personal interviews, the large preponderance of genetic risk factors for abuse of specific classes of psychoactive substance are non-specific. These results suggest that genetic variation in the primary sites of action of the psychoactive drugs, which differ widely across most drug classes, play a minor role in human individual differences in risk for DA. PMID:25660314

  19. Planets and satellites: tectonic twins

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2015-10-01

    There are only three solid planet-satellite pairs in the Solar system: Earth -Moon, Mars -Phobos, Pluto - Charon. For the first two pairs tectonic analogies were shown and explained by moving them in one circumsolar orbit. As it is known from the wave planetology [3, 4, 6], "orbits make structures". For the third pair the same was stated as a prediction based on this fundamental rule. Global tectonic forms of wave origin appear in cosmic bodies because they move in keplerian orbits with periodically changing accelerations. Warping bodies waves have a stationary character and obeying wave harmonics lengths. Starting from the fundamental 2πR-long wave 1 making the ubiquitous tectonic dichotomy (two-face appearance) warping wave lengths descend along harmonics. Very prominent along with the wave 1 are waves 2 responsible for tectonic sectoring superimposed on the wave 1 segments. Practically all bodies have traces of shorter waves making numerous polygons (rings) often confused with impact craters. Earth and the Moon moving in one circumsolar orbit both are distorted by wave 1, wave 2 and wave 4 features aligned along extent tectonic lines [4, 5]. At Earth they are: Pacific Ocean (2πR-structure) and Indian Ocean (πR-structure) from both ends with Malay Archipelago (πR/4-structure) in the middle. At Moon they are: Procellarum Ocean (2πR) and SPA Basin (πR) from ends and Mare Orientale (πR/4) in the middle. A regular disposition is surprising. Both Oceans and Basin occur on opposite hemispheres, lying in the middle both ring structures occur in the boundary between two hemispheres and are of the same relative size. These triads stretch along lines parallel to the equator (Earth) and with the angle about 30 degrees to it (Moon) indicating at a different orientation of the rotation axes in the ancient time [2]. On the whole, one could speak about a "lunar mould" of Earth [5] (Fig. 1-3). Another tectonic twin is the pair Mars -Phobos. Both bodies sharing one

  20. Late Language Emergence in 24-Month-Old Twins: Heritable and Increased Risk for Late Language Emergence in Twins

    ERIC Educational Resources Information Center

    Rice, Mabel L.; Zubrick, Stephen R.; Taylor, Catherine L.; Gayán, Javier; Bontempo, Daniel E.

    2014-01-01

    Purpose: This study investigated the etiology of late language emergence (LLE) in 24-month-old twins, considering possible twinning, zygosity, gender, and heritability effects for vocabulary and grammar phenotypes. Method: A population-based sample of 473 twin pairs participated. Multilevel modeling estimated means and variances of vocabulary and…

  1. 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.

  2. Investigations on the mechanical behavior of nanowires with twin boundaries by atomistic simulations

    SciTech Connect

    Tian, Xia

    2015-03-10

    Atomistic simulations are used to study the deformation behavior of twinned Cu nanowires with a <111> growth orientation under tension. Due to the existence of the twin boundaries, the strength of the twinned nanowires is higher than that of the twin-free nanowire and the yielding stress of twinned nanowires is inversely proportional to the spacings of the twin boundaries. Moreover, The ductility of the twin-free nanowire is the highest of all and it grows with the increasing spacings of the twin boundaries for twinned nanowires. Besides, we find that the twin boundaries can be served as dislocation sources as well as the free surfaces and grain boundaries.

  3. Twin nucleation and migration in FeCr single crystals

    SciTech Connect

    Patriarca, L.; Abuzaid, Wael; Sehitoglu, Huseyin; Maier, Hans J.; Chumlyakov, Y.

    2013-01-15

    Tension and compression experiments were conducted on body-centered cubic Fe -47.8 at pct. Cr single crystals. The critical resolved shear stress (CRSS) magnitudes for slip nucleation, twin nucleation and twin migration were established. We show that the nucleation of slip occurs at a CRSS of about 88 MPa, while twinning nucleates at a CRSS of about 191 MPa with an associated load drop. Following twin nucleation, twin migration proceeds at a CRSS that is lower than the initiation stress ( Almost-Equal-To 114-153 MPa). The experimental results of the nucleation stresses indicate that the Schmid law holds to a first approximation for the slip and twin nucleation cases, but to a lesser extent for twin migration particularly when considerable slip strains preceded twinning. The CRSSs were determined experimentally using digital image correlation (DIC) in conjunction with electron back scattering diffraction (EBSD). The DIC measurements enabled pinpointing the precise stress on the stress-strain curves where twins or slip were activated. The crystal orientations were obtained using EBSD and used to determine the activated twin and slip systems through trace analysis. - Highlights: Black-Right-Pointing-Pointer Digital image correlation allows to capture slip/twin initiation for bcc FeCr. Black-Right-Pointing-Pointer Crystal orientations from EBSD allow slip/twin system indexing. Black-Right-Pointing-Pointer Nucleation of slip always precedes twinning. Black-Right-Pointing-Pointer Twin growth is sustained with a lower stress than required for nucleation. Black-Right-Pointing-Pointer Twin-slip interactions provide high hardening at the onset of plasticity.

  4. A twin approach to unraveling epigenetics.

    PubMed

    Bell, Jordana T; Spector, Tim D

    2011-03-01

    The regulation of gene expression plays a pivotal role in complex phenotypes, and epigenetic mechanisms such as DNA methylation are essential to this process. The availability of next-generation sequencing technologies allows us to study epigenetic variation at an unprecedented level of resolution. Even so, our understanding of the underlying sources of epigenetic variability remains limited. Twin studies have played an essential role in estimating phenotypic heritability, and these now offer an opportunity to study epigenetic variation as a dynamic quantitative trait. High monozygotic twin discordance rates for common diseases suggest that unexplained environmental or epigenetic factors could be involved. Recent genome-wide epigenetic studies in disease-discordant monozygotic twins emphasize the power of this design to successfully identify epigenetic changes associated with complex traits. We describe how large-scale epigenetic studies of twins can improve our understanding of how genetic, environmental and stochastic factors impact upon epigenetics, and how such studies can provide a comprehensive understanding of how epigenetic variation affects complex traits.

  5. The twin paradox and Mach's principle

    NASA Astrophysics Data System (ADS)

    Lichtenegger, H.; Iorio, L.

    2011-12-01

    The problem of absolute motion in the context of the twin paradox is discussed. It is shown that the various versions of the clock paradox feature some aspects which Mach might have appreciated. However, the ultimate cause of the behavior of the clocks must be attributed to the autonomous status of spacetime, thereby proving the relational program advocated by Mach as impracticable.

  6. Twin Paradox in de Sitter Spacetime

    ERIC Educational Resources Information Center

    Boblest, Sebastian; Muller, Thomas; Wunner, Gunter

    2011-01-01

    The "twin paradox" of special relativity offers the possibility of making interstellar flights within a lifetime. For very long journeys with velocities close to the speed of light, however, we have to take into account the expansion of the universe. Inspired by the work of Rindler on hyperbolic motion in curved spacetime, we study the worldline…

  7. Creativity in Monozygotic and Dyzygotic Twins.

    ERIC Educational Resources Information Center

    Richmond, Bert O.

    The purpose of this study is to clarify further the relationships among creative, cognitive, and affective production of students. Thirteen pairs of twins, eight monozygotic (MZ), five dyzygotic (DZ), were administered the Torrance Tests of Creative Thinking, MMPI, and Revised Beta Examination. The F ratio for testing significance of within-set…

  8. NEW APPROACHES: The twins paradox explained

    NASA Astrophysics Data System (ADS)

    Linton, J. O.

    1997-09-01

    The well-known paradox of the space-travelling twins is easily stated, but it is not at all easy to explain, especially to a perspicacious audience. This essay attempts to set out an explanation (largely inspired by Paul Davies' book About Time [1]) which should be within the grasp of an intelligent sixth-former.

  9. A Pediatric Twin Study of Brain Morphometry

    ERIC Educational Resources Information Center

    Wallace, Gregory L.; Schmitt, J. Eric; Lenroot, Rhoshel; Viding, Essi; Ordaz, Sarah; Rosenthal, Michael A.; Molloy, Elizabeth A.; Clasen, Liv S.; Kendler, Kenneth S.; Neale, Michael C.; Giedd, Jay N.

    2006-01-01

    Background: Longitudinal pediatric neuroimaging studies have demonstrated increasing volumes of white matter and regionally-specific inverted U shaped developmental trajectories of gray matter volumes during childhood and adolescence. Studies of monozygotic and dyzygotic twins during this developmental period allow exploration of genetic and…

  10. Prediction of preterm birth in twins.

    PubMed

    Makrydimas, George; Sotiriadis, Alexandros

    2014-02-01

    About 13% of twins are born before 34 weeks and 7% before 32 weeks. The prediction of preterm birth in twins is based on the same tests as in singleton pregnancies. In twin pregnancies, the cut-off for short cervix at the second trimester scan is less than 25 mm (compared with 15 mm in singletons); length less than 20 mm is associated with 42% risk for birth before 32 weeks and cervical length less than 25 mm is associated with 28% risk for birth before 28 weeks. The measurement of cervical length in pregnancies with symptoms of preterm labour may have limited accuracy in predicting preterm birth. In asymptomatic women, a positive fetal fibronectin test seems to be associated with 35% risk for birth before 32 weeks and 40% risk for birth less than 34 weeks, whereas a negative test decreases the risk to 6% and 17%, respectively. The differences in the predictive value of tests between twins and singletons reflect the diverse pathophysiology of preterm birth between the two groups.

  11. Twinning of amphibian embryos by centrifugation

    NASA Technical Reports Server (NTRS)

    Black, S. D.

    1984-01-01

    In the frog Xenopus laevis, the dorsal structures of the embryonic body axis normally derive from the side of the egg opposite the side of sperm entry. However, if the uncleaved egg is inclined at lg or centrifuged in an inclined position, this topographic relationship is overridden: the egg makes its dorsal axial structures according to its orientation in the gravitational/centrifugal field, irrespective of the position of sperm entry. Certain conditions of centrifugation cause eggs to develop into conjoined twins with two sets of axial structures. A detailed analysis of twinning provided some insight into experimental axis orientation. First, as with single-axis embryos, both axes in twins are oriented according to the direction of centrifugation. One axis forms at the centripetal side of the egg and the other forms at the centrifugal side, even when the side of sperm entry is normal to the centrifugal force vector. Second, if eggs are centrifuged to give twins, but are inclined at lg to prevent post-centrifugation endoplasmic redistributions, only single-axis embryos develop. Thus, a second redistribution is required for high-frequency secondary axis formation. This can be accomplished by lg (as in the single centrifugations) or by a second centrifugation directed along the egg's animal-vegetal axis.

  12. Twin Valley, Wild Rice River, Minnesota. Addendum.

    DTIC Science & Technology

    1976-05-01

    David Rockwell, TSB, EPA Billy Fairless, CRL. EPA Gary Schenzel, Water Div, EPA Charlie Delos, Planning. EPA Michael Sullivan, Planning, EPA Harlan Hirt...Twin Valley-Norman 868 " WRR Hahnomen-Mahn 1,312 " WRR Felton-Clay 232 " Felton D. WRR Borup-Norman 128 " Ditch SBWRR Begon -Mahnomen 157 None Marsh WRR

  13. Osteogenesis imperfecta: cesarean deliveries in identical twins.

    PubMed

    Dinges, E; Ortner, C; Bollag, L; Davies, J; Landau, R

    2015-02-01

    Osteogenesis imperfecta is a congenital disorder resulting in multiple fractures and extremely short stature, usually necessitating cesarean delivery. Identical twins with severe osteogenesis imperfecta each of whom underwent a cesarean delivery with different anesthetic modalities are presented. A review of the literature and anesthetic options for cesarean delivery and postoperative analgesia for women with osteogenesis imperfecta are discussed.

  14. Monozygotic twins of different apparent sex

    SciTech Connect

    Yokota, Yukifumi; Fujino, Nobuyuki; Sato, Yoshiaki; Matsunobu, Akira; Tadokoro, Mamoru; Akane, Atsushi; Matsuura, Nobuo; Maeda, Tohru; Nakahori, Yutaka; Nakagome, Yasuo

    1994-10-15

    We report on twins of unlike sex who shared a 45,X/46,X, +mar karyotype. The mar chromosome was found to be Yq- by DNA analysis. Marker studies, including 8 VNTR loci, yielded a probability of monozygosity of 0.99999996. 16 refs., 1 fig., 1 tab.

  15. Heart Rate and Behavior of Twins.

    ERIC Educational Resources Information Center

    Boomsma, Dorret I.; Plomin, Robert

    1986-01-01

    Genetic and environmental influences on heart rate were studied in samples of twin pairs in middle childhood. Heart rate was measured in resting situation and under two task conditions. Heart rate was related to parental ratings of shyness, emotionality, and selective attention measure. Multivariate analysis suggested that covariance between heart…

  16. Preadolescent development: case studies in twins.

    PubMed Central

    Frank, R. A.; Cohen, D. J.

    1980-01-01

    The authors studied eight sets of healthy twins, ranging in physical maturity from prepubertal to late pubertal, and their parents, to assess psychological changes in early adolescence. A phase-specific psychosocial regression correlates with the biological onset of puberty. We present preliminary findings related to twinship, parental reactions, and longitudinal development, based on detailed case studies. Parents experienced increased conflict, detachment, and pride in response to their twins' psychosocial development at puberty. The more advanced child in a pair tended to lead in all spheres of adjustment-school success, heterosexual interest, peer friendships, and independent behavior. Although the more advanced child began to break away from his twin, in general the twin relationships remained close. Differences in personality traits and rate of psychosocial development within a twinship tended to remain consistent or to become accentuated. They were occasionally narrowed but rarely reversed from early childhood through early adolescence. Some of the differences were fostered by dissimilar patterns of identifying with the parents. PMID:7195631

  17. 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.

  18. Diabetes and Perinatal Mortality in Twin Pregnancies

    PubMed Central

    Luo, Zhong-Cheng; Zhao, Yan-Jun; Ouyang, Fengxiu; Yang, Zu-Jing; Guo, Yu-Na; Zhang, Jun

    2013-01-01

    Background Diabetes in pregnancy has been associated with a paradoxically reduced risk of neonatal death in twin pregnancies. Risk “shift” may be a concern in that the reduction in neonatal deaths may be due to an increase in fetal deaths (stillbirths). This study aimed to clarify the impact of diabetes on the risk of perinatal death (neonatal death plus stillbirth) in twin pregnancies. Methods This was a retrospective cohort study of twin births using the largest available dataset on twin births (the U.S. matched multiple birth data 1995-2000; 19,676 neonates from diabetic pregnancies, 541,481 from non-diabetic pregnancies). Cox proportional hazard models were applied to estimate the adjusted hazard ratios (aHR) of perinatal death accounting for twin cluster-level dependence. Results Comparing diabetic versus non-diabetic twin pregnancies, overall perinatal mortality rate was counterintuitively lower [2.1% versus 3.3%, aHR 0.70 (95% confidence intervals 0.63-0.78)]. Individually, both stillbirth and neonatal mortality rates were lower in diabetic pregnancies, but we identified significant differences by gestational age and birth weight. Diabetes was associated with a survival benefit in pregnancies completed before 32 weeks [aHR 0.55 (0.48-0.63)] or with birth weight <1500 g [aHR 0.61 (0.53-0.69)]. In contrast, diabetes was associated with an elevated risk of perinatal death in pregnancies delivered between 32 and 36 weeks [aHR 1.38 (1.10-1.72)] or with birth weight >=2500 g [aHR 2.20 (1.55-3.13)]. Conclusions Diabetes in pregnancy appears to be “protective” against perinatal death in twin pregnancies ending in very preterm or very low birth weight births. Prospective studies are required to clarify whether these patterns of risk are real, or they are artifacts of unmeasured confounders. Additional data correlating these outcomes with the types of diabetes in pregnancy are also needed to distinguish the effects of pre-gestational vs. gestational diabetes

  19. Morphology of Our Galaxy's 'Twin'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    NASA's Spitzer Space Telescope has captured these infrared images of a nearby spiral galaxy that resembles our own Milky Way. The targeted galaxy, known as NGC 7331 and sometimes referred to as our galaxy's twin, is found in the constellation Pegasus at a distance of 50 million light-years. This inclined galaxy was discovered in 1784 by William Herschel, who also discovered infrared light.

    The evolution of this galaxy is a story that depends significantly on the amount and distribution of gas and dust, the locations and rates of star formation, and on how the energy from star formation is recycled by the local environment. The new Spitzer images are allowing astronomers to 'read' this story by dissecting the galaxy into its separate components.

    The image, measuring 12.6 by 8.2 arcminutes, was obtained by Spitzer's infrared array camera. It is a four-color composite of invisible light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (yellow) and 8.0 microns (red). These wavelengths are roughly 10 times longer than those seen by the human eye.

    The infrared light seen in this image originates from two very different sources. At shorter wavelengths (3.6 to 4.5 microns), the light comes mainly from stars, particularly ones that are older and cooler than our Sun. This starlight fades at longer wavelengths (5.8 to 8.0 microns), where instead we see the glow from clouds of interstellar dust. This dust consists mainly of a variety of carbon-based organic molecules known collectively as polycyclic aromatic hydrocarbons. Wherever these compounds are found, there will also be dust granules and gas, which provide a reservoir of raw materials for future star formation.

    One feature that stands out in the Spitzer image is the ring of actively forming stars that surrounds the galaxy center (yellow). This ring, with a radius of nearly 20,000 light-years, is invisible at shorter wavelengths, yet has been detected at

  20. Siamese twins: killing one to save the other.

    PubMed

    Annas, G J

    1987-04-01

    The birth of Siamese twins joined at the chest (thoracopagus twins) and sharing a heart creates an ethical dilemma. Infants with conjoined hearts survive no more than a few months, and physicians must decide whether to give one child a chance at life by separating the twins and sacrificing one to give the other an intact heart. Annas reviews the ethical and legal discussions generated by the birth and treatment of thoracopagus twins at Philadelphia's Children's Hospital in 1977 and 1987. He considers most of the analogies used to justify the death of one twin to be strained. The situation becomes more complicated when there is no medical indication as to which twin has a better chance of surviving. Nevertheless, Annas concludes that the bleakness of the twins' prognosis if they remain joined justifies separation and the death of one child, despite the difficulty of developing a rationale for the act.

  1. Genetic and environmental contributions to the association between quantitative ultrasound and bone mineral density measurements: a twin study.

    PubMed

    Howard, G M; Nguyen, T V; Harris, M; Kelly, P J; Eisman, J A

    1998-08-01

    This study was designed to assess the relative contributions of genetic and environmental factors to the variation and covariation of quantitative ultrasound (QUS) measurements and their relationships to bone mineral density (BMD). Forty-nine monozygotic (MZ) and 44 dizygotic (DZ) female twins between 20 and 83 years of age (53 +/- 13 years, mean +/- SD) were studied. Digital (phalangeal) QUS (speed of sound [SOS]) and calcaneal QUS (broadband ultrasound attenuation [BUA] and velocity of sound [VOS]) were measured using a DBM Sonic 1200 ultrasound densitometer and a CUBA ultrasound densitometer, respectively. Femoral neck (FN), lumbar spine (LS), and total body (TB) BMD were measured using dual-energy X-ray absorptiometry. Familial resemblance and hence heritability (proportion of variance of a trait attributable to genetic factors) were assessed by analysis of variance, univariate, and multivariate model-fitting genetic analyses. In both QUS and BMD parameters, MZ twins were more alike than DZ pairs. Estimates of heritability for age- and weight-adjusted BUA, VOS, and SOS were 0.74, 0.55, and 0.82, respectively. Corresponding indices of heritability for LS, FN, and TB BMD were 0.79, 0.77, and 0.82, respectively. In cross-sectional analysis, both BUA and SOS, but not VOS, were independently associated with BMD measurements. However, analysis based on intrapair differences suggested that only BUA was related to BMD. Bivariate genetic analysis indicated that the genetic correlations between BUA and BMD ranged between 0.43 and 0.51 (p < 0.001), whereas the environmental correlations ranged between 0.20 and 0.28 (p < 0.01). While the genetic correlations within QUS and BMD measurements were significant, factor analysis indicates that common genes affect BMD at different sites. Also, individual QUS measurements appear to be influenced by some common sets of genes rather than by environmental factors. Significant environmental correlations were only found for BMD

  2. Personality and birth order in monozygotic twins adopted apart: a test of Sulloway's theory; Research Reviews: twin births and cancer risk in mothers, male sexual dysfunction, twin study of ultimatum game behavior; Human Interest: 'The Land of Twins', twin-like reunion-I, twin-like reunion-II.

    PubMed

    Segal, Nancy L

    2008-02-01

    A brief overview of Sulloway's (1996) theory of birth order and personality is presented. A reared apart twin approach for testing his personality findings regarding openness to experience and conscientiousness in first borns and later borns is described. This is followed by summaries of three recent twin studies. The topics include cancer risk in mother of twins, sexual dysfunction in males and responder behavior during ultimatum games. This article concludes with a discussion of twinning rates and rituals among the Yoruba of western Nigeria, and descriptions of two unusual reunions between siblings and twins.

  3. Dauphiné twins or not, that's the question

    NASA Astrophysics Data System (ADS)

    Sintubin, Manuel; Wenk, Hans-Rudolf

    2014-05-01

    Dauphiné twinning in trigonal low-quartz is defined by a two-fold axis (180° rotation) about the crystallographic c-axis [0001]. Dauphiné twinning has thus no effect on the orientation of the crystallographic axes of quartz, but transposes the positive and negative rhombs. Therefore, Dauphiné twinning remain undetectable by standard optical microscopy. Dauphiné twins were first resolved in euhedral quartz crystals by natural or artificial etching. In texture analysis, the different orientation distribution of the positive and negative rhombs indicates that Dauphiné twinning has likely been active within many polycrystalline quartz aggregates. Since the introduction of EBSD-OIM (SEM) Dauphiné twin boundaries can effectively be mapped in polycrystalline quartz aggregates. Dauphiné twins in quartz can be a primary microstructure, formed during crystal growth, or a secondary microstructure, resulting from transformational or mechanical twinning. Transformational Dauphiné twinning, occurring at the polymorphic transition of hexagonal high-quartz to trigonal low-quartz (573°C at atmospheric conditions), causes a variant selection through slight atomic displacements arising from internal thermal vibrations. Mechanical Dauphiné twinning in low-quartz, on the other hand, is stress-induced. It acts to align the direction of greatest elastic compliance, orthogonal to the positive rhombs, with the compressive principal stress direction. Dauphiné twin boundaries separate the two variant domains within the quartz grain. The question, though, is which of the variant domains is the 'twin' and which is the 'host'. In previous work on mechanical Dauphiné twinning in naturally deformed quartz-bearing rocks, the distinction between 'host' and 'twin' has been made mostly arbitrarily, guided by an observations bias (e.g. smallest fraction in grain represents the 'twin') or an interpretational bias (e.g. twins develop at grain boundaries). However, with respect to grains

  4. Brain regulation of appetite in twins12

    PubMed Central

    Melhorn, Susan J; Mehta, Sonya; Kratz, Mario; Tyagi, Vidhi; Webb, Mary F; Noonan, Carolyn J; Buchwald, Dedra S; Goldberg, Jack; Maravilla, Kenneth R; Grabowski, Thomas J; Schur, Ellen A

    2016-01-01

    Background: Neural responses to highly energetic food cues are robust and are suppressed by eating. It is not known if neural responsiveness to food cues is an inherited trait and possibly even one that mediates the genetic influences on body weight that have been previously observed. Objective: We investigated the inherited influence on brain responses to high-calorie visual food cues before and after a meal. Design: With the use of a monozygotic twin study design, 21 healthy monozygotic twin pairs consumed a standardized breakfast and, 3.5 h later, underwent the first of 2 functional MRI (fMRI) scans with the use of visual food cues. After the first fMRI session, twins consumed a standardized meal, which was followed by the second fMRI. Serial ratings of appetite and food appeal were obtained. An ad libitum buffet was used to measure total caloric and macronutrient intakes. Intraclass correlations (ICCs) were used to test for inherited influences by comparing whether intrapair similarity was greater than interpair similarity. Results: Body mass index was highly correlated within twin pairs (ICC: 0.96; P < 0.0001). ICCs also showed a strong intrapair similarity for the meal-induced change in hunger (ICC: 0.41; P = 0.03), fullness (ICC: 0.39; P = 0.04), and the appeal of fattening food (ICC: 0.57; P < 0.001). Twins ate a similar number of kilocalories at the buffet (ICC: 0.43; P = 0.02). Before the meal, the global brain activation across regions involved in satiety processing was not more similar in twins than in unrelated individuals. However, significant ICCs were present after the meal (ICC: 0.39; P = 0.04) and for the meal-induced change in activation by high-calorie visual food cues (ICC: 0.52; P < 0.01). Conclusion: Inherited factors influence both satiety perception and the effect of a meal to alter regional brain responses to images of highly energetic food. This trial was registered at clinicaltrials.gov as NCT02483663. PMID:26739033

  5. Global gene expression analysis of amniotic fluid cell-free RNA from recipient twins with twin-twin transfusion syndrome

    PubMed Central

    Hui, Lisa; Wick, Heather C.; Moise, Kenneth J.; Johnson, Anthony; Luks, Francois; Haeri, Sina; Johnson, Kirby L.; Bianchi, Diana W.

    2013-01-01

    Objective To understand the biological pathways involved in twin-twin transfusion syndrome (TTTS) by performing global gene expression analysis of amniotic fluid (AF) cell-free RNA. Methods Prospective whole transcriptome microarray study analyzing cell-free RNA in AF from TTTS recipient twins and singleton controls. Significantly differentially-regulated genes in TTTS cases (N= 8) vs. matched controls (N = 8) were identified and pathways analyses performed. Significant gene expression differences between Stage II TTTS recipients (N = 5) and Stage III TTTS recipients with abnormal Doppler measurements (N = 5) were also analysed. Results Analysis of paired data from TTTS cases and controls revealed differential expression of 801 genes, which were significantly enriched for neurological disease and cardiovascular system pathways. We also identified cardiovascular genes and pathways associated with the presence of critically abnormal Doppler measurements in Stage III TTTS recipients. Conclusions This study provides the first transcriptome-wide data on the impact of TTTS on fetal development. Our results show that gene expression involving neurological and cardiovascular pathways are altered in recipient fetuses prior to surgical treatment. This has relevance for the origins of long-term complications seen in survivors and for the development of future fetal biomarkers. PMID:23640821

  6. Twin Interactions in Pure Ti Under High Strain Rate Compression

    NASA Astrophysics Data System (ADS)

    Zhou, Ping; Xiao, Dawu; Jiang, Chunli; Sang, Ge; Zou, Dongli

    2017-01-01

    Twin interactions associated with {11 overline{2} 1} (E2) twins in titanium deformed by high strain rate ( 2600 s-1) compression were studied using electron backscatter diffraction technique. Three types of twins, {10 overline{1} 2} (E1), {11 overline{2} 2} (C1), and {11 overline{2} 4} (C3), were observed to interact with the preformed E2 twins in four parent grains. The E1 variants nucleated at twin boundaries of some E2 variants. And the C3 twins were originated from the intersection of C1 and E2. The selection of twin variant was investigated by the Schmid factors (SFs) and the twinning shear displacement gradient tensors (DGTs) calculations. The results show that twin variants that did not follow the Schmid law were more frequently observed under high strain rate deformation than quasi-static deformation. Among these low-SF active variants, 73 pct (8 out of 11) can be interpreted by DGT. Besides, 26 variants that have SF values close to or higher than their active counterparts were absent. Factors that may affect the twin variant selections were discussed.

  7. Twinned silicon and germanium nanocrystals: Formation, stability and quantum confinement

    SciTech Connect

    Yu, Ting; Pi, Xiaodong Ni, Zhenyi; Zhang, Hui; Yang, Deren

    2015-03-15

    Although twins are often observed in Si/Ge nanocrystals (NCs), little theoretical investigation has been carried out to understand this type of important planar defects in Si/Ge NCs. We now study the twinning of Si/Ge NCs in the frame work of density functional theory by representatively considering single-twinned and fivefold-twinned Si/Ge NCs. It is found that the formation of twinned Si/Ge NCs is thermodynamically possible. The effect of twinning on the formation of Si NCs is different from that of Ge NCs. For both Si and Ge NCs twinning enhances their stability. The quantum confinement effect is weakened by twinning for Si NCs. Twinning actually enhances the quantum confinement of Ge NCs when they are small (<136 atoms), while weakening the quantum confinement of Ge NCs as their size is large (>136 atoms). The current results help to better understand the experimental work on twinned Si/Ge NCs and guide the tuning of Si/Ge-NC structures for desired properties.

  8. Role of deformation twins in static recrystallization kinetics of high-purity alpha titanium

    NASA Astrophysics Data System (ADS)

    Won, Jong Woo; Lee, Taekyung; Hong, Seong-Gu; Lee, Yongmoon; Lee, Jeong Hun; Lee, Chong Soo

    2016-11-01

    The importance of deformation twins in static recrystallization kinetics of high-purity alpha titanium was investigated by carrying out thermal annealing tests of deformed materials in combination with electron-backscatterdiffraction- based microstructural analysis. Prior to thermal annealing, the material was compressed to a true strain of 0.22 along three directions to introduce different twinning characteristics. Our results showed that deformation twins substantially promoted the static recrystallization process by deepening the microstructural inhomogeneity induced by the formation of twin boundaries and twinning-induced crystallographic lattice reorientation. Twin morphology was also observed to be important because it influenced the extent of microstructural inhomogeneity. Intersecting twin morphology, caused by the activation of multiple twin variants, was more effective than parallel twin morphology, caused by the activation of a single twin variant (or a twin variant pair), because it gave rise to more twin boundaries, more twin boundary junctions (intersections, triple junctions, etc.), and greater in-grain crystallographic orientation spread.

  9. Effects of twinning on gestation length, retained placenta, and dystocia.

    PubMed

    Echternkamp, S E; Gregory, K E

    1999-01-01

    Constraints to maximal productivity from twinning in beef cattle include increased incidence of dystocia and retained placenta, longer postpartum interval, and lower conception rate. Incidence and cause(s) of the shorter gestation length and of the increased retained placenta and dystocia associated with twinning were evaluated for 3,370 single and 1,014 twin births produced in a population of cattle selected for natural twin births. Gestation length was shorter for twin than for single pregnancies (275.6 vs. 281.3 d, P<.01) and likely contributed to the higher incidence of retained placenta associated with twin births (27.9 vs. 1.9%; P<.01). Incidence of retained placenta was also higher in the spring (March-April) than in the fall (August-September) calving season (18.3 vs. 11.4%; P<.01). The higher incidence of dystocia with twins than with singles (46.9 vs. 20.6%, P<.01) was primarily due to abnormal presentation (37.0 vs. 4.5%, respectively) of one or both twin calves at parturition. First- (40.5%) and second- (22.7%) parity dams with a single birth had more (P<.01) dystocia than older dams (13.4%), whereas dystocia was not affected (P>.10) by parity with twin births. Because of the shorter gestation length and the increased incidence of retained placenta and(or) dystocia, achievement of increased productivity with twinning in cattle necessitates intensive management of twin-producing dams and their calves during the calving season. Management of the increased dystocia can be facilitated by preparturient diagnosis of twin pregnancies, enabling timely administration of obstetrical assistance to facilitate delivery of twin calves and to increase their neonatal survival.

  10. The Impact of Preschool Twins' Physical Difficulties on Parental Perceptions towards Separation, Closeness and Friendship

    ERIC Educational Resources Information Center

    Markodimitraki, Maria; Linardakis, Michalis; Kypriotaki, Maria; Manolitsis, George

    2016-01-01

    The aims of this study were to: (a) provide descriptive data of twins with physical difficulties among 120 Greek twins of preschool age; and (b) to investigate the impact of twins' health condition on parental perceptions towards twins' separation, closeness and friendship. The administration of School Policy for Twins and Higher Multiples…

  11. Finite Deformation by Elasticity, Slip, and Twinning: Atomistic Considerations, Continuum Modeling, and Application to Ceramic Crystals

    DTIC Science & Technology

    2009-03-01

    finite shear strains associated with slip and deformation twinning and improper lattice rotations across twin boundaries . Nonlinear anisotropic...of (2) results from gradients in twin fractions, e.g. interface dislocations at tapered twin boundaries . Disclination models of twins (Clayton et

  12. Twin differentiation of cognitive ability through phenotype to environment transmission: The Louisville Twin Study

    PubMed Central

    Beam, Christopher R.; Turkheimer, Eric; Dickens, William T.; Davis, Deborah Winders

    2015-01-01

    The Louisville Twin Study is one of the most intensive twin studies of cognitive ability. The repeated measurements of the twins are ideal for testing developmental twin models that allow for the accumulation of gene-environment correlation via a phenotype to environment (P=>E) transmission process to explain twins’ divergence in mean ability level over time. Using full-scale IQ scores from 566 pairs of twins (MZ=278; DZ=288), we tested whether a P=>E transmission model provided better representation of actual developmental processes than a genetic simplex model. We also addressed whether the induced gene-environment correlation alters the meaning of the latent nonshared environmental factors with a simple numerical method for interpreting nonshared environmental factors in the context of P=>E transmission. The results suggest that a P=>E model provided better fit to twins’ FSIQ data than a genetic simplex model and the meaning of the nonshared environment was preserved in the context of P=>E. PMID:26468113

  13. [Superfecundation in etiology of twin pregnancy].

    PubMed

    Malinowski, Witold; Waszyński, Edmund

    2006-10-01

    Superfecundation is the fertilisation of two or more ova from the same cycle by sperm from separate acts of sexual intercourse. The term is also sometimes used to refer to the instances of two different males fathering fraternal twins, though this is more accurately known as heteropaternal superfecundation. This therefore leads to the possibility of twins also being half-siblings. This way of formation of multiply pregnancy aroused and it arouses still among doctors on whole world. This problem aroused large interest also among Polish doctors. For example, we found mention of superfecundation in first Polish medical journal, in Primitiae physico-medicae..., given in Leszno in years 1750-1753. Authors introduced relate opinion of superfecundation in aetiology of multiple pregnancies in historical aspect, as early as from Old Testament to present times as well as current state of medical knowledge of such a situation.

  14. Exoplanets: the quest for Earth twins.

    PubMed

    Mayor, Michel; Udry, Stephane; Pepe, Francesco; Lovis, Christophe

    2011-02-13

    Today, more than 400 extra-solar planets have been discovered. They provide strong constraints on the structure and formation mechanisms of planetary systems. Despite this huge amount of data, we still have little information concerning the constraints for extra-terrestrial life, i.e. the frequency of Earth twins in the habitable zone and the distribution of their orbital eccentricities. On the other hand, these latter questions strongly excite general interest and trigger future searches for life in the Universe. The status of the extra-solar planets field--in particular with respect to very-low-mass planets--will be discussed and an outlook on the search for Earth twins will be given in this paper.

  15. Twin screw granulation: steps in granule growth.

    PubMed

    Dhenge, Ranjit M; Cartwright, James J; Hounslow, Michael J; Salman, Agba D

    2012-11-15

    The present work focuses on the study of the progression of granules in different compartments along the length of screws in a twin screw granulator (TSG). The effects of varying powder feed rate; liquid to solid ratio and viscosity of granulation liquid on properties of granules was studied. The bigger granules produced at the start of the process were found to change in terms of size, shape and strength along the screw length at all the conditions investigated. The granules became more spherical and their strength increased along the screw length. Tracer granules were also introduced in order to understand the role of kneading and conveying elements in the TSG. The kneading elements promoted consolidation and breakage while the conveying elements led to coalescence, breakage and some consolidation. The results presented here help to provide a qualitative and quantitative understanding of the twin screw granulation process.

  16. Coherent light in intense spatiospectral twin beams

    NASA Astrophysics Data System (ADS)

    Peřina, Jan

    2016-06-01

    Intense spatio-spectral twin beams generated in the regime with pump depletion are analyzed applying a suggested quantum model that treats the signal, idler, and pump fields in the same way. The model assumes the signal and idler fields in the form of the generalized superposition of signal and noise and reveals nonzero signal coherent components in both fields, contrary to the models developed earlier. The influence of coherent components on the properties of intense twin beams is elucidated. The interference pattern formed in the process of sum-frequency generation and that of the Hong-Ou-Mandel interferometer are shown to be able to experimentally confirm the presence of coherent components.

  17. Twin screw granulation - review of current progress.

    PubMed

    Thompson, M R

    2015-01-01

    Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique.

  18. Interstitial twin pregnancy: A unique case presentation.

    PubMed

    Garretto, Diana; Lee, Lan Na; Budorick, Nancy E; Figueroa, Reinaldo

    2015-09-01

    Early recognition and timely treatment of an interstitial pregnancy is imperative to avoid the high morbidity and mortality of this type of ectopic pregnancy. We report a case of twin interstitial pregnancy that was initially missed on initial sonogram and was subsequently recognized at our institution by transvaginal sonography. The patient underwent open laparoscopic surgery with cornual wedge resection but suffered infundibulopelvic ligament hemorrhage and subsequently required ipsilateral salpingo-oophorectomy. She did well and was discharged home a day later.

  19. Tank Tests of Twin Seaplane Floats

    NASA Technical Reports Server (NTRS)

    Herrman, H; Kempf, G; Kloess, H

    1928-01-01

    The following report contains the most essential data for the hydrodynamic portion of the twin-float problem. The following points were successfully investigated: 1) difference between stationary and nonstationary flow; 2) effect of the shape of the step; 3) effect of distance between floats; 4) effect of nose-heavy and tail-heavy moments; 5) effect of the shape of floats; 6) maneuverability.

  20. Twin brain and ardhanareeshwara: an interesting comparison.

    PubMed

    Balodhi, J P

    1987-04-01

    This article is a scientific interpretation of Vedic, Upanishadic, Tantric and Puranic conceptions of Cakras & 'Ardhanareeshwara' in the light of modern neuro psychological research. It also attempts to make striking similarities between the 'twin brain' and the concept of 'Ardhanareeshwara' and to show how the Ancient Indian sages conceptualized this 'two in one', brain reality long ago what neurosciences are just trying to understand now.