One Twin (one + twin)

Distribution by Scientific Domains


Selected Abstracts


Primary tooth emergence in Australian children: timing, sequence and patterns of asymmetry

AUSTRALIAN DENTAL JOURNAL, Issue 3 2010
S Woodroffe
Abstract Background:, Information on the timing and sequence of human tooth emergence is valuable when analysing human growth and development, predicting the age of individuals, and for understanding the effects of genetic and environmental influences on growth processes. This paper provides updated data on the timing and sequence of primary tooth emergence in Australian children for both clinicians and researchers. Methods:, Twins were recruited from around Australia with data collected through parental recording of twins' primary tooth emergence. One twin from each pair was then randomly selected to enable the calculation of descriptive statistics for timing, sequence and asymmetry in tooth emergence. Results:, The first and last primary teeth emerged, on average, at 8.6 months and 27.9 months, respectively, with teeth emerging in the order: central incisor, lateral incisor, first molar, canine, second molar. Left-side antimeric teeth were more likely to emerge before their right-side counterparts but this was not statistically significant. At least 35% of all antimeric pairs had emerged within two weeks of each other, serving as a useful guideline for assessing symmetrical versus asymmetrical development. Conclusions:, Primary tooth emergence in Australian twins is occurring later than reported previously for Australian singletons but is consistent with findings for singletons in other ethnic groups. The most common sequence of primary tooth emergence appears to be consistent in twins and singletons and has not changed over time. [source]


Marked discordance for myopia in female monozygotic twins

CLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2006
Mohamed Dirani BOrth & OphthSc(Hons)
Abstract Female monozygotic twins aged 54 years discordant for myopia are reported. One twin presented with bilateral high myopia (right eye = ,6.00/+0.50 × 5°, left eye = ,6.00/+0.50 × 45°) and her identical twin had no significant refractive error (right eye = ,0.50/plano, left eye = ,0.50/+0.75 × 40°). An explanation for the striking refractive discordance seen in this case report is yet to be determined. [source]


Does reactivity to stress cosegregate with subclinical psychosis?

ACTA PSYCHIATRICA SCANDINAVICA, Issue 1 2009
A general population twin study
Objective:, This study assessed the relationship between stress reactivity (trait 1) and psychosis (trait 2) across genetically related persons (cross-twin, cross-trait design) to examine whether stress reactivity is an uncontaminated and unconfounded familial marker of psychosis risk. Method:, Reactivity to stress and subclinical psychotic experiences were assessed in 289 female, general population twin-pairs. Cross-trait, within-twin associations investigating the association between stress reactivity and subclinical psychotic experiences in each person, were calculated. In addition, cross-trait, cross-twin associations were calculated to assess whether stress reactivity in one twin was moderated by subclinical psychotic experiences in the co-twin. Results:, Cross-trait, within-twin analyses showed significant associations between stress reactivity and subclinical psychotic experiences in each person. In addition, the cross-trait cross-twin analyses showed that stress reactivity in twin 1 was significantly moderated by subclinical experiences in the co-twin. Conclusion:, The results suggest that the psychosis phenotype cosegregates with increased emotional reactivity to stress in daily life. [source]


Psychological aspects of prenatal diagnosis and its implications in multiple pregnancies

PRENATAL DIAGNOSIS, Issue 9 2005
Elizabeth Bryan
Abstract Couples expecting twins are often unrealistically optimistic and are therefore unprepared for the complications as well as the practical and emotional impact the birth of twins can have on the family. All such couples will need information and support throughout the pregnancy and beyond. In this review, the various aspects that should be addressed are discussed, in particular, health care workers and counsellors need to be aware of the stress experienced by parents who have been through prolonged treatment for infertility or who face the special problems associated with the loss of one twin (implies the loss could be other than death). Copyright © 2005 John Wiley & Sons, Ltd. [source]


Prognosis for the co-twin following single-twin death: a systematic review

BJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 9 2006
SSC Ong
Background, Following single-twin death, the perinatal mortality and morbidity for the surviving co-twin is increased but difficult to quantify. We present data on prognosis from a systematic review. Objectives, We aimed to determine the incidence of a) co-twin death, b) neurological abnormality and c) preterm delivery for the surviving co-twin following single-twin death after 14 weeks of gestation. Search strategy, Literature was identified by searching two bibliographical databases and specialist journals between 1990 and 2005. Selection criteria, The selected studies of ,5 cases reported on perinatal death and/or neurodevelopmental delay of the surviving co-twin. Data collection and analysis, Studies were assessed for quality and data extracted to allow computation of rates. The data were inspected for heterogeneity using a Forrest plot and examined statistically using the chi-square test. Data from individual studies were pooled within subgroups defined by prognosis. Main results, The search strategy yielded 632 potentially relevant citations. Full manuscripts were retrieved for 54 citations and 28 studies were finally included in the review. Following the death of one twin, the risk of monochorionic and dichorionic co-twin demise was 12% (95% CI 7,11) and 4% (95% CI 2,7), respectively. The risk of neurological abnormality in the surviving monochorionic and dichorionic co-twin was 18% (95% CI 11,26) and 1% (95% CI 0,7), respectively. The risk of preterm delivery was 68% (95% CI 56,78) and 57% (95% CI 34,77), respectively. Where there was comparative data within studies, the odds of monochorionic co-twin intrauterine death was six times that of dichorionic twins (OR 6.04 [95% CI 1.84,19.87]). Neurological abnormality was also higher in monochorionic compared with dichorionic pregnancies (OR 4.07 [95% CI 1.32,12.51]). Author's conclusions, More prospective research is required to inform decision making on this subject, especially with data that allow stratification based upon chorionicity. [source]