bluuebunny/crossref_metadata_2025_split huggingface dataset:
Twin Children in Volunteer Registries: Biases in Parental Participation and Reporting
Authors: Hay D.A. , Clifford C. , Derrick P. , Hopper J. , Renard B. , Theobald T.M. 
Published: July 2016

AbstractThe biases in volutary participation by adult twins are well known but less attention has been paid to twin children where parents decide on participation and provide much of the information. Several aspects of reporting including the assessment of zygosity are compared in four large Australian data bases: 1) a nationwide compulsory (and hence representative) survey of literacy and numeracy; 2) a nationwide “Twins in School” survey of parents and teachers of twins run through Education Departments and AMBA, the parents organisation in conjunction with LaTrobe; 3) the LaTrobe Twin Study which is a longitudinal program involving frequent interactions between families and researchers, and 4) the Australian NHMRC Twin Registry which has surveyed a large sample of their families with twin children by mail. One potential bias comes when recruitment is on a continuing basis as in the LaTrobe Twin Study and the Australian Twin Registry when differences between “early” and “late” enrolling families arise. One difference between the four samples arose from parents being much more likely to contrast their twins and to report problems in one but not the other, whereas teachers' and psychologists' assessments of these same children generally reported much smaller intrapair differences. Future studies should have some common questions to provide comparative data on such biases. Key questions are proposed for this area, mainly on the perceived need for different forms of remediation, together with other recommendations about the minimal essential baseline data set for a registry.
Study of Gene-Environment Effects on Development of Hyperopia: A Study of 191 Adult Twin Pairs from the Finnish Twin Cohort Study
Authors: Teikari J. , Koskenvuo M. , Kaprio J. , O'Donnell J. 
Published: July 2016

AbstractThe Finnish Twin Cohort material was used to estimate genetic and environmental effects in the etiology of hyperopia (farsightedness). All twin pairs in the cohort born before year 1927 (age 60 years and over at the time of the study), with both members alive, were sent a questionnaire. The questionnaire included questions of past and present eye diseases, visits to ophthalmologists, use of glasses and other vision-related questions. The hyperopia was assessed by asking the patients to send their last prescription for glasses to the authors. Twins with any eye disease affecting refraction (cataract, corneal damage), operation or trauma to their eyes were discarded from the present study. In 191 pairs (80 monozygotic and 111 dizygotic pairs) one or both members of the pair had a hyperopic refractive error. The correlations of refraction between right and left eyes of both MZ and DZ pairs were high (Spearman Rank Correlations of 0.86-0.89). The intrapair correlations among MZ pairs were higher (0.44 for right and 0.45 for left eyes) than intrapair correlations among DZ pairs (0.24 for right and 0.15 for left eyes). The variances were not significantly different among MZ and DZ pairs. The classical analysis of heritability gave an estimate of 0.75 for hyperopia. The result suggests that genetic factors are important in hyperopia and especially in hyperopia of higher degree.
Monozygotic Twin Resemblance in Fatness and Fat Cell Lipolysis
Authors: Després J.P. , Bouchard C. 
Published: July 2016

AbstractSix skinfold measurements, and percent body fat and fat-free weight derived from the underwater weighing technique were obtained in 43 pairs of male and 44 pairs of female monozygotic (MZ) twins. A fat tissue biopsy was performed in the suprailiac region in 20 male and 16 female pairs in order to determine mean adipocyte diameter and basal lipolysis as well as epinephrine maximally stimulated lipolysis (10−4M). Twin resemblance in body fatness is clearly demonstrated by the analysis of the between MZ sibships over the within MZ shibship means of squares for all skinfold measurements, percent body fat and fat free weight (P < 0.01). Within MZ pair similarity is as high in female as in male pairs for body fatness. Moreover, members of the same twin pair resemble one another significantly for fat cell size and fat cell lipolytic activities, particularly when epinephrine stimulated. In female MZ pairs, additional studies with control over the menstrual cycle are needed to clarify the case of isolated fat cell basal lipolysis.
Estimates of Genetic Variance for Some Selected Morphometric Characters: A Twin Study
Authors: Sharma J.C. , Sharma K. 
Published: July 2016

AbstractResults on genetic variability in some of the morphometric characters on head and face, body girths and skin folds, based on 45 MZ and 67 like-sex DZ twin pairs, are presented. The data were subjected to a method which eliminated possible biases in the estimated genetic variances that could result from heterogeneity of total variances between zygosities of the 17 head and face measurements, heterogeneity was observed for only bizygomatic diameter. Head breadth means differed between MZ and DZ twins, indicating bias in the trait's genetic variance analysis. The results indicated a significant genetic component in these morphometric traits. For 11 girth and skinfold measurements, the t'-test based on hierarchical structure of twin data, also failed to reveal any appreciable difference between the mean values of MZ and DZ twins. Heterogeneity of total variance between zygosities was observed for three skinfold measurements, ie, biceps, triceps and suprailiac. The girth measurements, however, did not reveal any heterogeneity of total variances between the zygosities. The estimates of genetic variance revealed stronger genetic component for the girths than for the skinfolds.
Toward a Theory of Human Multiple Birthing: Sociobiology and r/K Reproductive Strategies
Authors: Rushton J. Philippe 
Published: July 2016

AbstractUsing symbols from population biology, a continuum of reproductive strategies can be distinguished ranging from r, the production of large numbers of offspring provided with minimal care, to K, the production of few offspring nurtured intensively. While all humans are at the K end of the continuum, some are proposed to be more so than others. If multiple egg production is part of an r-reproductive strategy, certain facts may be ordered. Compared to mothers of singletons, for example, mothers of DZ twins nave a lower age of menarche, a shorter menstrual cycle, a higher number of marriages, a higher rate of coitus, more illegitimate children, a closer spacing of births, a greater fecundity, more wasted pregnancies, a larger family, an earlier menopause, and an earlier mortality. Further, all twins have a shorter gestation period, a lower birth weight, and a greater incidence of infant mortality, with DZ twins having a greater frequency of health disorders, a higher mortality rate, and a lower rate of enrollment in volunteer registries. Multiple birthing also occurs more frequently in families of lower than of higher social status, and in those of African than of European and especially than of Orientai descent.
The Recent Trends in Multiple Births and Stillbirth Rates in Japan
Authors: Imaizumi Y. 
Published: July 2016

AbstractThe twinning rate remained nearly Constant up to 1968, then decreased in 1974 and gradually increased with the year. The triplet birth rate remained nearly Constant up to 1974, then increased up to 1982, where the rate was 1.8 times higher than in 1968, and decreased thereafter. On the other hand, the quadruplet birth rate remained nearly Constant up to 1968, was eightfold in 1975, then decreased until 1984 and suddenly increased to 8 per million births in 1985. The higher multiple birth rates since 1974 was attributed to the higher proportion of mothers treated with ovulation-inducing hormones in Japan. The stillbirth rates decreased to 2/5 for male twins and to 1/3 for female twins during the 25-year period from 1960, to 2/5 for triplets and to 1/5 for quadruplets during the 34-year period from 1951.
Excessive Twinning in a Rural American Genealogy: The Demographic Pedigree
Authors: Sheets John W. 
Published: July 2016

AbstractExcessive twinning in an extended family of rural Missouri concentrates in the isolated generations of 1874-1930s. Moderate inbreeding, larger sibships to older mothers, and access to local doctors may have combined to enhance this familial twinning. These biosocial factors are similar to an isolated case of excessive twinning in Scotland.
Twinning in New England in the 17th–19th Centuries
Authors: Miura T. , Kawana H. , Nonaka K. 
Published: July 2016

AbstractVital records of Saybrook and Plymouth in New England from the 17th century were investigated. Among 8,562 maternities 81 twin maternities were found, the twinning rate being 0.95%. Twinning rate was low at the lst and 2nd births as compared with the 3rd or later births, and was highest at the 7th and 8th births (1.6%). Twin maternity seemed to be a strong risk factor to terminate reproduction, particularly after 6 or more children had been delivered. The rate of mothers who had any other child (“fertile” mothers) at the 7th or later birth order was significantly lower for twin (13%) than for singleton maternities (63%). Twinning rate also varied by the size of offspring of a mother, and those mothers who had 5 or 6 children showed the highest twinning rate (1.3%). Those fertile mothers who had 7 or more children showed the lowest twinning rate (0.74%), although an exceptionally higher twinning rate was seen at their last births. Elongation of the last birth interval was observed for each group of every family size, and higher twinning rates were generally observed at their last births. Reduction in fecundity and rise in twinning rate seem to have occurred simultaneously at the last stage of the reproductive period of mothers, regardless of their family size.
Alternate Changes in Birth Seasonality of Twins During 1971–1984 in Japan
Authors: Nakamura I. , Amau Y. , Nonaka K. , Miura T. 
Published: July 2016

AbstractBirth dates of 1,536 twin-pairs in 1971-1984 were collected from the members of an association of twins' mothers. The seasonal variation of twinning changed every 2-4 years. Years when twinning rate was higher in the summer-fall season (1971-72, 1976-77, 1982-84) and those when a peak of the rate was not observed (1973-75, 1978-81) appeared alternately. In years with a summer-fall peak, the elevation of twinning in the summer-fall season was detected consistently in both like- and unlike-sexed and in both MZ and DZ twin groups. The twinning seasonality in these years, however, was not evident in twin births of mothers who were born in May-July. These results suggest the possibility that seasonal factors which influence the twinning rate be not multiple-ovulation-inducing but probably abortion-inducing factors and most likely seasonally epidemic microbes.
Cyclic Variations of Twin Births at Isle-aux-Coudres: A Case/Control Approach
Authors: Philippe P. 
Published: July 2016

AbstractTwins and singletons were matched for several confounding factors. The monthly distribution of twin births and that of singleton births were compared with a uniform allocation of births over the year. Opposite seasonal variations emerged that were confirmed by a case/control comparison. Twins occurred more often in winter and early spring while singletons proved to be relatively few; singleton peaked in the fall season when the risk of a twin birth was low. These trends held across maternal age at birth and the time period of birth. Results suggest that the conception of a twin pair is higest in spring and early summer and lowest in winter. The role of sunlight in the twinning liability is discussed along with the role of sexual intercourse. That twin-prone mothers are usually more fecund in spring and early summer is a distinct possibility.
Serial Amniocenteses in the Treatment of Twin to Twin Transfusion Complicated with Acute Polyhydramnios
Authors: Feingold M. , Cetrulo C.L. , Newton E.R. , Weiss J. , Shakr C. , Shmoys S. 
Published: July 2016

AbstractTwin to twin transfusion, complicated by acute polyhydramnios in a monozygous twin pregnancy, is a difficult clinical problem. A precipitous course usually results in termination of the pregnancy within a few days and often is associated with a high perinatal mortality rate. Two cases are presented that were treated with repeated amniocenteses for the relief of extreme abdominal discomfort and to prevent imminent premature labor. The amount of amniotic fluid removed each time varied from 300 cc to 1200 cc, which was enough to relieve symptoms but not enough to induce uncontrolled uterine activity. A total of 3500 cc and 4750 cc of amniotic fluid were removed from the first and the second patient, respectively. The procedure was found to be safe and resulted in prolonging the pregnancies by 14 and 11 days, respectively. This management, with the addition of tocolysis and close fetal surveillance can offer some hope in an otherwise hopeless situation.
Spontaneous Drawing and the Individuality of Twins
Authors: Gedda L. 
Published: July 2016

Only rarely have geneticists, neurobiologists and psychologists availed themselves of twins for the study of the human mind's individuality. I believe, on the contrary, that twin data represent an invaluable means of research also for phenomena connected with human individuality and the functioning of the nervous system.To this end I thought of having MZ and DZ twins take a creativity test by means of spontaneous drawings of a single subject applied to individual MZ and DZ twin pairs.The preselected twins totalled 31 MZ and 13 DZ pairs of an age span during which the twins live together and experience the same environmental influences.The creativity test I devised consists of asking the twins to make a drawing of the family mealtime scene at which they all participate. The drawings were to be made on identical pieces of white paper, selecting colors from the same box of colored pencils given to each of them. When the test was explained, each twin was placed in a different room with no possibility of communication, and was asked to make the drawing, supervised at a distance by an assistant.In order to analyze the drawings, I established ten parameters: 1) First impression at a glance; 2) Choice of colors; 3) Choice of perspective; 4) Choice of persons' positions; 5) Emphasis on twins; 6) Shape of table; 7) Table settings and food dishes; 8) Room furniture; 9) Drawing of building; 10) Landscape.
Twins: Are They at Risk? A Longitudinal Study of Twins and Nontwins from Birth to 18 Years of Age
Authors: Åkerman B. Alin , Fischbein S. 
Published: July 2016

AbstractThe purpose of this study has been a comparison of a group of twins (145 pairs) and a whole cohort of singletons (114,828 individuals) born 1953 and living in the Stockholm metropolitan area in 1963. The twins and singletons have been followed from birth onwards. A pertinent question is whether twins are at greater risk at birth and whether they are predisposed to below-average mental and physical growth. The results show that twins are more susceptible to lower birth weight, shorter gestation period and birth complications. These factors also seem to have a lasting effect on later physical and mental development. Monozygotic twins, twin girls, and male twins with low birth weight, seem to be particularly at risk for below-average mental and physical growth. An interaction between social background and birth weight can also be seen for the male twin group.
Gestational Age-Specific Birthweights of Twins Versus Singletons
Authors: Luke B. , Witter F.R. , Abbey H. , Feng T. , Namnoum A.B. , Paige D.M. , Johnson T.R.B. 
Published: July 2016

AbstractIn order to more adequately characterize patterns of intrauterine growth retardation in twins, the mean birthweights of all nonanomalous white or black twins born between 24 and 41 weeks of gestation and surviving until discharge over an 11-year period (547 infants) and all similar singletons (19,072 infants) were compared by completed weeks of gestation. Between 24 and 35 weeks of gestation, the mean birthweights for the 547 twins and the 19,072 singletons were comparable and did not consistently differ statistically. From 36 to 41 weeks gestation, however, the difference became large, consistent, and statistically significant for each week at P < 0.0001. This difference was present among all subgroups of twins, ie, in all males, females, blacks, and whites; it was still evident when the sample was further stratified by both race and sex (black males, white males, black females, white females). These data suggest a pattern of growth retardation in twins compared to singletons which is large, consistent, and statistically significant beginning at 36 weeks gestation. Clinically, these data also suggest the need for ultrasonic examination early in gestation (24-32 weeks) to document normal growth and to provide baseline data, and show the importance of such monitoring later in gestation, specifically after 36 weeks.
Blood Pressure Discordance and Lifestyle: Japanese Identical Twins Reared Apart and Together
Authors: Hayakawa K. , Shimizu T. 
Published: July 2016

AbstractA total of 198 pairs of monozygotic twins reared apart and together were surveyed on their lifestyle and blood pressure through mailed questionnaires. The age of the subjects ranged from 47 to 87 years. The intrapair concordance rate on blood pressure increased from 51% (age of separation 0-5) to 78% (age of separation 26 and over) as the age of separation advanced. The concordance rate on occupation was 59% at the age of separation 0-5 and 87% at the age of separation 26 and over. The intrapair concordance on the food intake (egg, meat, fish, milk and salty seasoning) was positively correlated with the age of separation. Hayshi's quantification theory III (multivariate analysis) was used to claryfy the lifestyle pattern in 39 MZ pairs discordant on blood pressure. There were three factors (meat, milk and occupation) which were closely related with each other in the “non-hypertensive” twins, while lifestyle were not patterned in the “hypertensive” twins. The concordance rate of these three items increased along with the rise of concordance rate of blood pressure as the age of separation advanced.
Cardiovascular Reflexes in Monozygotic Twins Discordant for Exposure to Organic Solvents
Authors: Matikainen E. , Juntunen J. , Koskenvuo M. , Antti-Poika M. , Kaprio J. 
Published: July 2016

AbstractEighteen pairs of monozygotic twins discordant for long-term occupational exposure to organic solvents were examined for disturbances of cardiovascular reflexes. All of the subjects were asymptomatic, and considered themselves healthy. No significant differences were observed between the exposed and the nonexposed twins. The finding suggests that occupational solvent exposure at these particular levels is unlikely to cause disturbances of the autonomic nervous function.
Twin Study on Myopia
Authors: Lin L.L.-K. , Chen C.-J. 
Published: July 2016

AbstractIn order to reassess the relative importance of genetic and environmental factors in the development of myopia in Chinese schoolchildren, 90 pairs of MZ and 36 pairs of like-sex DZ twins were enrolled for detailed ophthalmological examination about their ocular refractions. Corneal curvatures and axial lengths were also measured. With equivalent settings of the range for concordance, corneal curvatures showed higher concordance rate (84%) than ocular refractions (65%) and axial lenghts (59%) in MZ twins. F-test on the intrapair variances between MZ and DZ twins revealed a significant hereditary role in determining the ocular refraction and its optical components. The degree of genetic determination was expressed by heritability indices, which were derived from intraclass correlation coefficients. The diversity of sample ages and refractions, while making the obtained data difficult to further explore the gene-environment interaction, led to the observation of more intrapair differences with age and myopic progression in MZ twins.
Atrial Activity and Cardiovascular Response to Stress in Triplets: Short Case Report
Authors: Campbell S. Villatico , Maio F. Di , Scioli A. , Sciacca A. , Brenci G. , Gedda L. 
Published: July 2016

Using high-resolution electrocardiography (HRE), we have previously examined the morphological aspects of the atriogram in a set of DZ triplets comparing the MZ and the DZ pairs [3]. We now repeated the recordings on the triplets, three years after the first studies, in order to evaluate the individual morphological reproducibility of the atriogram and the cardiovascular response to effort and to stress by means of provocative tests [1-3].We studied a set of female DZ triplets aged 15 years, born normally at the 39th week of gestation, with two chorions and three amnions. We compared the responses to the individual provocative tests, and repeated the analysis of the atriograms after three years. We therefore used the HRE, the Bruce protocol ergometric test, and the sympathetic stimulation tests: handgrip test, cold pressure test, arithmetic mental test (Table).
Teratomorfism in the Urinary Tract of MZ Twins: Short Case Report
Authors: Gedda L. , Brenci G. , Laurenti C. , De Dominicis C. , Mattioli D. 
Published: July 2016

A case of 15-years old, Roman male twins affected by balanic hypospadia is reported. Previous corrective surgery had not been satisfactory, leaving both boys with a curvature of the last portion of the penis. Urographic examination, carried out upon presentation, revealed in both patients a mirror renal ectopy with fusion of the two kidneys. In both, the displaced malformed kidney is below the normally situated one. In depth examination shows: 1) that the malformation concerns not only external genitals but also internal urogenital organs because of the monolateral ectopy of the normal kidney and the malformation of the ectopic kidney in both twins; 2) that the twins are MZ and that their teratological specularity is biologically of interest.Specularity, or mirror imaging, is a well known phenomenon in twins, particularly MZ twins. It may involve slight forms, such as handedness, or rare forms, such as those involving single organs, like the heart, which can be on the left side in one twin and on the right in the MZ cotwin. That must occur in the early embryogenetic stages, and various environmental and genetic factors may be involved. In particular, one can speculate that genetic variations in cell-adhesion molecules (CAM) and/or the late time of splitting of the conceptus to originate the two twins, may all play a role.
Finnish Twins Reared Apart III: Personality Factors
Authors: Langinvainio H. , Kaprio J. , Koskenvuo M. , Lönnqvist J. 
Published: July 2016

AbstractThis study is based on data from 165 adult twin pairs separated at 10 years or less. Information on personality factors: extraversion (E) and neuroticism (N) (EPI scale short from), life satisfaction (LS) (Allardt) and stress of daily activities (SDA) was obtained as part of the questionnaire study carried out in the entire Finnish Twin Cohort in 1975. Later in 1979 a questionnaire sent to the twins reared apart yielded a scale (range 7-30 points) measuring the environmental dissimilarities after separation (reliability 0.83). The effect of separation on personality factors by analysis of variance of individual data was studied. Sex, zygosity and age-at-separation were included in the models. The overall expalanatory rates were low (2.1-4.4%). The definitive study group was formed by selecting those pairs with a dissimilarity score greater than 15. The following intraclass correlations were obtained: