bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nature-Nurture Interaction in Different Types of School Environments A Longitudinal Study
Authors: Fischbein Siv 
Published: July 2016

AbstractA model of nature-nurture interaction in school situations emanating from a longitudinal Swedish twin project is presented. This model implies that interactional effects measured by MZ-DZ within-pair comparisons over time are related to the type of behavior studied, as well as teacher and pupil influences at different levels. In a more permissive and stimulating school situation, hereditary factors are hypothesized to be more influential (decisive for behavioral variation) than in a more restrictive and nonstimulating situation. A study of such interactional effects will require longitudinal measurements of pupil behavior as well as teacher and parental influences. To acquire a variation in permissiveness/restrictiveness and stimulation/nonstimulation at the societal level, comparisons are made between twins attending grade 4-6 in compulsory schools in Sweden and twins of the same age attending Israelian Kibbutz schools.
Dominance and Submissiveness Between Twins. II. Consequences for Mental Health
Authors: Moilanen Irma 
Published: July 2016

AbstractIn a follow-up study of 234 twin pairs, now aged 12-20 yrs, the intertwin relationships were evaluated by the parents and the twins themselves. The dominance-submissiveness aspect was inquired from three separate points of view, physical dominance, psychic dominance, and role of the spokesman. These three different aspects of dominance reflected on the twins' well being and mental health in somewhat different ways. The submissiveness in one area was often compensated by equality or dominance in another area, with only about 10% of adolescents being submissive or dominant in all three areas. According to the parents' reports, the most submissive twins suffered most often from psychosomatic symptoms, and the most dominant ones from nervous symptoms. The twins who themselves reported to be most submissive had most often somatic complaints and scored highest in the Kovacs' Depression Inventory.
Family History and Birthweight in Monozygotic Twins Concordant and Discordant for Psychosis
Authors: Lewis S.W. , Chitkara B. , Reveley A.M. , Murray R.M. 
Published: July 2016

AbstractIn a sample of monozygotic twins, intrapair differences in reported birthweight were larger in those pairs discordant for later psychosis, compared to pairs concordant for psychosis. A trend towards less family history of psychiatric disorder was also found in the discordant pairs.
New Frontiers of Gemellology
Authors: Gedda Luigi 
Published: July 2016

The good result of this congress (the fifth of the series), in terms of quality of papers and number of participants, proves we were on the right track when in 1974 we founded the International Society for Twin Studies, and even more proves that the interest in gemellology is increasing.I wish to thank our many colleagues who contributed to the promotion, construction and success of this field of biomedical research, and particularly Gordon Allen, Ian MacGillivray, Walter Nance, Paolo Parisi, and of course Aldur Eriksson.For my part, I would like to emphasize that going from the title “Study of Twins” given to my book in 1951 to the word gemellology placed in the title of our quarterly Acta Geneticae Medicae et Gemellologiae in 1952, I wanted to affirm: first, that the study of twins is a branch of modern genetics; second, that the study of twins represents a “logos,” that is, a subject composed of acquired concepts, of constant phenomena and specific methods of research on twins in normality, in pathology and in population. With this word, now also adopted by Professor Nance in his Presidential Address, “Introduction to Gemellology,” twin research has become an identified field of science.In order that the Amsterdam Congress may be as fruitful as the previous ones, I believe it useful to look out of the window of the future with you to see some roads which could be new frontiers of gemellology.
Zygosity Partitioning of Small Twin Samples
Authors: Allen Gordon , Hrubec Zdenek 
Published: July 2016

AbstractWhen the Weinberg estimate of the proportion of monozygotic pairs is quite deviant from that in the source population, it is likely to be wrong because Weinberg's difference is much less stable than the zygosity proportions. A formula is proposed for the probability distribution of possible compositions of a small sample of twins based on sex concordance in the sample and zygosity proportions in the source population.
An Assessment of Perinatal Mortality in Twin Pregnancies in Dundee
Authors: Osbourne G.K. , Patel N.B. 
Published: July 2016

AbstractAn analysis of all perinatal deaths occurring in twin pregnancies in Dundee women from 1956 to 1983 was performed. The uncorrected perinatal mortality rate fell from 116/1000 births in 1956-60 to 16/1000 births in 1981-83, this fall almost entirely taking place after 1975. Causes of death were identified using the Aberdeen Classification and a reduction in deaths in all cause groupings occurred. About half of the deaths were in the Premature, Cause Unknown group and a marked decrease in deaths in this group made the largest contribution to the improved perinatal mortality rate. This fall was partly due to a reduction in the incidence of extreme prematurity and low birth weight. Changes in obstetric management which may have influenced outcome included the introduction of routine early pregnancy ultrasound scanning, the use of tocolytic drugs, intrapartum fetal monitoring, epidural analgesia and an increase in Caesarean section rate from 2% in 1956-60 to 39% in 1981-83.
A Low Rate of Perinatal Deaths for Twin Births
Authors: Papiernik E. , Mussy M.A. , Vial M. , Richard A. 
Published: July 2016

AbstractA specific prenatal care program is proposed to prevent preterm deliveries in twin pregnancies, with ultrasound scanning, early work leave and home visits by midwifes. A four-year study has been conducted on 197 pregnancies (160 early followed and booked and 37 late referred). It can be shown that early preterm births and very low birth weights are less frequent in the followed group than in published data, as well as in the late referred pregnancies. The total perinatal mortality rate is 25.6 per 1000 total births.
Bed Rest in Twin Pregnancy
Authors: Kappel B. , Hansen K.B. , Moller J. , Faaborg-Andersen J. 
Published: July 2016

AbstractA total of 146 twin pregnancies were studied to evaluate the importance of bed rest. A significantly reduced frequency of preterm delivery was found after bed rest in hospital as compared to bed rest at home or no bed rest at all. An increase in gestational age and in birth weight was seen after bed rest. No effect was found on the intrauterine increase of fetal weight per time. Early routine ultrasound is recommended, so that effective bed rest may be instituted in due time.
President's Address: Twinning in Families of Triplets
Authors: Eriksson A.W. 
Published: July 2016

AbstractA study was conducted on twinning in relatives of consecutive triplet sets in the Åland Islands in the years 1740-1939. The incidence of twinning in sibships of triplets was extremely high, 80/1000 (56/1000 before and 143/1000 after the triplet maternity). In Finland as a whole, 1905-1954, the twinning rate was among mothers of triplets 38/1000, ie, about 2.6 times the rate in general population, and was higher after (48/1000) than before the triplet maternity (34/1000). In the sibships of fathers of triplets there was a low rate of twinning (below 10/1000) both of same-sexed (SS) and of opposite-sexed (OS) triplets. Among sibships of mothers of OS triplets the twinning rate was 18/1000 and among mothers' sibships of SS triplets 26/1000. The series of triplet families from both Åland and Finland as a whole indicate a considerably higher frequency of twinning on the maternal than on the paternal side. The sibships of OS triplets in Finland have higher twinning rates than sibships of SS triplets (50/1000 vs 27/1000). In sibships of triplets, not only the DZ but also the MZ twinning rates were approximately twice as high as those in the general population. The triplet rates in Finland were increasing strongly with maternal age and were in the last century among mothers of 30-39 years of age considerably higher than among mothers from this century. This, in combination with higher mean parity, may explain the high rates of multiple maternities in sibships of triplets in the past. The rate of triplet maternities seems to be more sensitive to sociodemographic changes than the rate of twin maternities. Mothers of triplets in Finland had a high frequency (more than 40%) of prenuptially conceived firstborn children. This, and a short protogenesic interval indicate that triplet-prone mothers are more fecundable, ie, they conceive with greater ease and/or may have a better physical condition than other women for completing a gestation with multiple embryos.
Trends in Monozygotic and Dizygotic Twinning Rates by Maternal Age and Parity — Further Analysis of Italian Data, 1949-1985, and Rediscussion of US Data, 1964-1985
Authors: Allen G. , Parisi P. 
Published: July 2016

AbstractThe dizygotic twinning rate in Italy, adjusted for maternal age and parity, declined from 8.9/1000 in 1949-1953 to 6.0/1000 in 1978-81, but may have stabilized or recovered slightly in the early 1980s. The long decline was greatest in the oldest mothers, and the recent increase, if any, has been principally in first births and in women under 30. The monozygotic rate rose from 3.8/1000 in 1969-73 to 4.3/1000 in 1982-85, having been relatively stable prior to that period. No good explanation for these trends is apparent.
Decrease in Twinning Rate in a Hospital in Tokyo During World War II
Authors: Nakamura I. , Nonaka K. , Miura T. 
Published: July 2016

AbstractIn order to investigate changes in twinning rate during World War II and postwar years, when the people in Tokyo suffered from malnutrition, about 80,000 delivery records during 1924-86 at one hospital in downtown Tokyo were examined. The twinning rate decreased from 1.47% in the 1920s to 0.81% in the 1980s. During the 1940s, the rate was 1.03% for 1940-42 and 0.94% for 1948-49, but it dropped down to 0.70% for 1943-47. In 1945, when Tokyo was heavily bombed repeatedly to be burnt out, and the people suffered from severe malnutrition, only one case of twinning was found among 305 maternities at this hospital (0.33%). While the mean birth weight of term singleton babies was 2953 g in 1940-41, it decreased to 2918 g in 1943-47, especially to 2856 g in 1945. This change in birth weight evidenced that the nutritional conditions in Tokyo became worse in 1943-47. This report suggests that the twinning rate decreased also during this period in Tokyo when the people suffered from malnutrition.
Living Habits and Personality Development of Adolescent Twins: A Longitudinal Follow-up Study in a Birth Cohort from Pregnancy to Adolescence
Authors: Moilanen I. , Rantakallio P. 
Published: July 2016

AbstractThe living habits of 289 twins in a one-year birth cohort beginning during pregnancy and followed up to adolescence were compared with those of 11,623 singletons and two sets of controls matched either by maternal factors and place of residence only or by these and perinatal morbidity, all from the same cohort. The twins went in for sports more often than the singletons or any kind of controls. A nonsignificant trend was found indicating that twins smoked less often than their matched controls. The twins also used alcohol less often than their controls. The intrapair similarities of twins were higher than the similarities of twins and either type of controls in all four variables tested: sports, smoking, use of alcohol, as well as having been drunk.
Qualitative and Quantitative Aspects on Mathematics Achievement in MZ and DZ Twins
Authors: Lange A.L. , Fischbein S. 
Published: July 2016

AbstractMathematics achievement test results have been collected for 22 MZ and 24 DZ same-sex twin pairs in the Swedish compulsory school. The twins were approximately 11-13 years of age and attended grades 4, 5, or 6. The twin pairs were part of a larger collaborative study between Israel and Sweden (the KAM-project). Teachers were asked how they planned and evaluated their work in the subjects Swedish and Mathematics. In addition to this, results for the twins on Maths tests given by the teachers in their regular work were collected. These tests were thus used by the teachers as an instrument to evaluate the educational process. Intrapair similarity for MZ and DZ twins has been compared for qualitative and quantitative aspects of the Maths tests. Different tests were used by the teachers but the same criteria have been used in the comparison. MZ twins are somewhat more similar than DZ twins for both the qualitative and quantitative aspects. Only one quantitative aspect, however, percentage of correct answers, shows a significant difference between the twin categories. A comparison was also made of intrapair similarity in classes, where the teachers differed according to planning and evaluation of their education. Irrespective of that, the MZ twins seemed to be more similar than the DZ twins in number of correct answers on the Maths tests. Educational implications are discussed.
Using MZ Twins in Experimental Research to Test for the Presence of a Genotype-Environment Interaction Effect
Authors: Bouchard C. , Pérusse L. , Leblanc C. 
Published: July 2016

AbstractDespite some evidence that genotype-environment interaction (G×E) effects may be involved in the variation observed in behavioral and biological traits, few attempts have been made to detect and quantify this component of genetic variation in humans. We propose that one way to achieve this goal is to challenge several genotypes in a similar manner, submitting both members of several MZ twin pairs to an ethically acceptable experimental treatment capable of inducing an adaptative response. In this situation, the G×E effect can be assessed with a two-way analysis of variance for repeated measures on one factor, the treatment effect. In this design, twins are considered nested within the pair, whereas the treatment effect is considered a fixed variable. The intrapair resemblance in the response to the treatment is quantified with an intraclass correlation coefficient computed with between-sibhips and within-sibhips means of squares. To illustrate this approach, changes induced by long-term endurance training were studied in 10 MZ twin pairs. Significant intrapair resemblance in the response of maximal oxygen uptake was observed, with about 7 to 8 times more variance between pairs than within pairs. This design with MZ twins may be helpful in the study of human variation for multifactorial phenotypes.
Chronogenetics: A Meeting Point for Medicine and Twin Research
Authors: Gedda Luigi 
Published: July 2016

AbstractThe program of any individual's vital cycle encoded in the genetic information is executed according to a time schedule that is the object of study of Chronogenetics. MZ twins provide the best evidence of the existence of this hereditary biological time and they represent, therefore, the natural test of Chronogenetics. Twin research can thus serve medicine in developing its most modern perspective, individual preventive medicine. Moreover, through approaches such as the Twins-Living-Apart Test, twin research can help to identify the influences of the environment on the health of man.
Familial Factors in Mortality with Control of Epidemiological Covariables. Swedish Twins Born 1886-1925
Authors: Hrubec Z. , Floderus-Myrhed B. , de Faire U. , Sarna S. 
Published: July 2016

AbstractA Cox proportional hazard regression analysis was carried out that evaluated age-specific death risk among 21,890 twins born in Sweden during 1886 through 1925 and followed during 1962 through 1980. Cotwin's survival was used as the primary covariable, and auxiliary covariables were smoking, marital status and, among men, police registration for alcohol abuse. In each age, sex and zygosity group, except the oldest DZ males, cotwin's mortality had a significant, independent, positive relationship to the mortality risk of the individual. The auxiliary covariables, except marital status among females, had significant, independent, positive relationships to mortality among the youngest twins of both zygosity groups and in the middle age group of MZ twins. In the oldest age group, the death of MZ cot wins was the only variable significantly related to the individual's mortality. Heritability estimates for the age-specific probability or death risk, developed by different methods for different analysis groups, range between 0.4 and 0.6. They have reasonable internal consistency, are not much affected by the covariates, and are in agreement with other studies that did not control covariates.
Responses of Blood Glucose and Serum Insulin to Peroral Glucose Load in Normoglycemic Twins
Authors: Kesäniemi Y.A. , Koskenvuo M. , Miettinen T.A. 
Published: July 2016

AbstractFasting blood glucose and serum immunoreactive insulin (IRI) and the responses of blood glucose and serum IRI to peroral glucose challenge were investigated in middle-aged normoglycemic male twins of 17 monozygotic (MZ) and 18 dizygotic (DZ) pairs recruited from the Finnish Twin Cohort Study. Also, the role of obesity and diet in the regulation of glucose and insulin metabolism was estimated. The fasting and 2 hr postprandial (PP) glucose showed higher pairwise correlations in MZ (r =0.78 and 0.56) than DZ (r = 0.08 and −0.05) pairs whereas fasting and PP insulin levels and the areas under the PP glucose and insulin curves were weakly and similarly correlated in MZ and DZ twins. The pairwise correlations of the 1/2 hr and 1 hr, but not the fasting and 2 hr insulin/glucose ratios, were somewhat higher in MZ (R = 0.51 and 0.53) than DZ (r = = 0.28 and 0.30) pairs. In MZ twins, the intrapair differences in the body mass index were significantly correlated with those in the fasting and 2 hr PP glucose and insulin levels and those in the fasting and 1/2 hr insulin/glucose ratios (r from 0.47 to 0.76). Also, the intrapair differences in the dietary fat calories were correlated positively, but those in the calories derived from carbohydrates negatively, with the intrapair differences in several parameters of the glucose and insulin metabolism. These data suggest that the environmental contribution to the regulation of glucose and insulin metabolism in subjects within the normoglycemic range may be quite strong. Of the environmental factors studied, obesity and dietary fat consumption seem to have powerful regulatory roles, particularly in the response of insulin to the glucose load.
Statistical Models for the Twinning Rate
Authors: Fellman J.O. , Eriksson A.W. 
Published: July 2016

AbstractLinear regression models are used to explain the variations in the twinning rates. Data sets from different countries are analysed and maternal age, parity and marital status are the main regressors. The model building technique is also used in order to study the secular decline in the twinning rate. Linear regression technique makes it possible to compare the effect of different factors but the method requires sufficiently disaggregated data.
The Non-Decline in U.S. Twin Birth Rates, 1964–1983
Authors: Allen Gordon 
Published: July 2016

AbstractDetailed twin birth rates for the United States are unavailable since 1964. In 1983 the crude twinning rate for women of white race was higher than in 1964, but there had been great changes in maternal age and parity. Indirect standardization for maternal age and birth order provides estimated total twinning rates that can be compared over the entire period. The adjusted rates for whites show a nearly continuous increase except after a 2-year reporting hiatus, 1969-70, when rates dropped back 10%. In blacks the adjusted rate increased between 1966 and 1978, except for the 1968-71 shift. The distributions of rate increases by maternal age and by race argue against effects of medical ovulation stimulants, but a disproportionate increase of triplets argues for such effects. Study is needed of rates specific for maternal age and parity, rather than of total rates.
Possible Mechanism of the Heredity of Twinning
Authors: Gedda L. , Brenci G. 
Published: July 2016

It is a frequent observation that twinning runs in the families [5] and we have recently reported that such is also the case with Gregor Mendel's pedigree [4]. The problem we are concerned with, now, is the identification of the “gemellogenetic” factor postulated by Gedda already in 1951 [2].We thought we should start by going back to experimental embryology. Clearly, as shown by the experimentally induced MZ twinning in Triton or the spontaneous multiple MZ twinning in Armadillo, there must exist a temporal threshold below which individual parts of a single conceptus can still show totipotence.Interestingly, recent studies of molecular histology have stressed the role of cell membranes and of membrane receptors in the transmission of specific messages related to the position and function of the cell. This has led Edelman [1], in particular, to identify a specific kind of molecule that appears early in-embryonic development and is responsible for cell adhesion, thus contributing to organogenesis and the shaping of the embryo by regulating cell movements and the topologic development of tissues.These so-called cell-adhesion molecules (CAM) are proteins that can differentiate both in function and in expression. In terms of function, there are molecules responsible for the adhesion of nerve cells (N-CAM), of liver cells (L-CAM), etc. In terms of expression, there are embryonic forms (E-CAM) and adult forms (A-CAM), the former being characterized by larger quantities of sialic acid. This chemical difference accounts for a different aggregation effect on the cells, that is, for a different cell adhesion. Moreover, the E-CAM and A-CAM can be interconverted, at different times and with variable speed.
Cost of Care and Prevention of Preterm Births in Twin Pregnancies
Authors: Tresmontant Raphaël , Héluin Gérard , Papiernik Emile 
Published: July 2016

This study describes a 5-year survey of activity in a single institution, and the effects of a change of policy for prevention of preterm birth in twin pregnancies.The results show the advantages and drawbacks from the financial and medical viewpoints.
Back Pain: A Study of Twins
Authors: Bengtsson B. , Thorson J. 
Published: July 2016

AbstractTo evaluate the relationship between genetic factors and back pain, 5029 MZ and 7876 DZ twin pairs were investigated by a questionnaire. The data were analyzed with regard to physical symptoms, eg, back pain, and certain work conditions. Pain was reported by about 17% of the male and 13% of the female twins in the material. The occurrence of back pain was strongly associated with work load, especially among the male twins. Twin concordance regarding back pain was considerably higher in MZ than in DZ twins. Of four groups who were studied, statistically significant differences between the two twin categories were observed in three cases. This result supports the assumption that a relationship exists between genetic factors and the occurrence of back pain. Official registrations for sick-leave pay in a sample of 247 twins confirmed the interview information on back pain. Just a few cases were wrongly classified, ie, they were sick-listed because of back pain but had stated no back pain in the questionnaire.