bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intrapair Differences of Physical Aging and Longevity in Identical Twins
Authors: Hayakawa K. , Shimizu T. , Ohba Y. , Tomioka S. , Takahasi S. , Amano K. , Yura A. , Yokoyama Y. , Hayakata Y. 
Published: July 2016

AbstractThe genetic and environmental contributions to physical aging (hair graying, balding, presbyopia) and longevity (age at death) were examined by within-pair comparison in monozygotic (MZ) and dizygotic (DZ) twins in later adulthood. Physical aging was investigated on 135 pairs of adult twins aged over 50. Hair graying and hair loss (baldness) showed significantly higher rates of concordance in the MZ twins than in the DZ twins. The intrapair difference of the degree of hair graying was negligible in 79%, slight in 15% and striking in 5% among the MZ pairs; while negligible in 40%, slight in 50% and striking in 10% among the DZ pairs. The intrapair difference of the degree of hair loss was negligible in 92%, slight in 8% (and striking in none) among the MZ pairs; while negligible in 69%, slight in 25% and striking in 6% among the DZ pairs. The age at onset of presbyopia showed a slightly higher rate of concordance in the MZ than in the DZ pairs. Longevity (age at death) was surveyed on 184 pairs of twins who died at over 40 years of age. The intrapair difference of longevity was 6.65 ± 5.6 years (maximum 18.0; minimum 0.04) in the MZ pairs, and 8.66 ± 7.2 years (maximum 18.6; minimum 2.9) in the DZ pairs. The MZ pairs showed a slightly smaller within-pair difference of longevity than the DZ pairs.
Risk Factors for Cognitive Aging in Adult Twins
Authors: Hayakawa K. , Shimizu T. , Ohba Y. , Tomioka S. 
Published: July 2016

AbstractMonozygotic (MZ) and dizygotic (DZ) twins in later adulthood were studied in order to examine genetic and environmental contributions to the decline of cognitive performance. In this study, 118 twin pairs took a comprehensive medical examination at a university hospital. Cognitive function was measured by the Wechsler Adult Intelligence Scale (WAIS). The intraclass correlation coefficients on Digit Span (D) and Digit Symbol (DS) subtests of the WAIS did not show any significant difference between MZ and DZ twins although Block Design (BD) showed a significant difference. The values of the intraclass correlation coefficients were mostly around 0.5 and showed significant within-pair similarity of test scores. The mean score of D, DS and BD declined with advancing age. The intraclass correlation coefficients for D, DS and BD were around 0.2 in the MZ twins reared apart, and around 0.6 in the MZ twins reared together. These results indicated a significant environmental influence on cognitive aging in later adulthood.
Twinning and the r/K Reproductive Strategy: A Critique of Rushton's Theory
Authors: Allen G. , Eriksson A.W. , Fellman J. , Parisi P. , Vandenberg S.G. 
Published: July 2016

AbstractThe theory of r selection, favoring population growth, as opposed to K selection, favoring more efficient utilization of resources, has in recent years been applied by Rushton to contrast human ethnic groups in terms of their r/K reproductive strategies, suggesting the existence of a continuum from r groups, producing many offspring but providing little parental care, to K groups, producing few offspring but providing much parental care. Rushton's theory, which is largely based on ethnic differences in twinning rates, is here critically examined. It is pointed out that twinning rate differences are not necessarily genetic in origin since various environmental factors clearly play a role, and also that twinning, as a mode of reproduction, is not necessarily an r strategy, considering the high prenatal and perinatal selection to which it has been, and still is, associated. Moreover, Rushton misinterprets a number of relevant aspects related to the biology of twinning. The claim that ethnic differences in twinning rates provide evidence for an r/K typology in human populations with respect to reproductive strategies does not appear to be warranted.
Triplet Pregnancy: A 10-Year Review of 105 Cases at Harare Maternity Hospital, Zimbabwe
Authors: Crowther C.A. , Hamilton R.A. 
Published: July 2016

AbstractDuring the 10-year period, 1975-1984, 105 triplet pregnancies were delivered at Harare Maternity Hospital, Zimbabwe, among 286,338 pregnancies in the Greater Harare Unit, giving an incidence of triplets of 1:2,727. The mean gestational age at delivery was 32.5 wk with 81 women (77.1%) delivering before 37 wk. Primigravidas delivered at a significantly earlier mean gestational age (P < 0.05) and had a higher perinatal mortality (P < 0.001) compared with grand multigravidas. Of the 315 babies, 277 (87.9%) weighed < 2500 g. The overall perinatal mortality rate was 327‰, with a pernital mortality rate of 146‰ for infants weighing ≥ 1000 g. Women hospitalised for bed rest during the antenatal period had fewer perinatal deaths compared with those diagnosed during the antenatal period, but not hospitalised for bed rest (P < 0.02). No difference was found in the mean gestational age at delivery or the mean birth weights between these two groups. Among infants ≥ 28 wk gestation there were fewer perinatal deaths in triplets delivered by cesarean section compared with triplets delivered vaginally (P < 0.0004). This suggests that cesarean section may offer the optimal mode of delivery in triplet pregnancy.
Evaluation of Zygosity Diagnosis in Twin Pairs Below Age Seven by Means of a Mailed Questionnaire
Authors: Bønnelykke B. , Hauge M. , Holm N. , Kristoffersen K. , Gurtler H. 
Published: July 2016

AbstractThe mothers of a consecutive series of 125 same sexed pairs of twins aged 6 months to 6 1/2 years completed a mailed questionnaire concerning the physical similarity of the twin partners. Zygosity diagnoses were first determined blindly on the basis of the answers given by the mothers, who did not know the result of the blood group test when fullfilling the questionnaire. Next, the results were compared with the zygosity determination based on examination of erythrocyteserum- and enzyme-groups. It turned out that a few simple questions distinguished well enough between MZ and DZ pairs, with a frequency of misclassification of 4%, leaving 5% as unclassifiable. It is concluded that twin zygosity can be estimated by a simple questionnaire with sufficient accuracy even in very young twin pairs. This has relevant implications for more extensive twin studies where the use of a wide spectrum of serological characters would imply too high expenses.
Decline of the Twinning Rate in Brazil
Authors: de Moraes M.H. Baena , Beiguelman B. , Krieger H. 
Published: July 2016

AbstractThe twinning rate during a twenty-year period (1965-1985) was investigated at five-year intervals in four Brazilian hospitals. During this period the twinning rate has decreased significantly (from 10.68‰ to 8.11‰), being highly negatively correlated with the five-year intervals (r = −0.97). This change was due mainly to the decline in dizygotic twinning, since the incidence of DZ twins has fallen from around 7‰ in 1965 to around 3.6‰ in 1985. The detected decline in DZ twinning seems to be due to the remotion of the fertility advantage of the more fecundable DZ twin-prone women by the introduction of effective birth control at the present, while some other mechanisms are causing the decline irrespective of the type of twinning.
Analisi delle Dinamiche del Travaglio e del Parto Gemellare Mediante l'Uso di un Programma Computerizzato
Authors: Valle A. , Reina S. , Casini M. 
Published: July 2016

AbstractLo studio dei fenomeni dinamici del travaglio e del parto gemellare suggerisce che l'azione uterina inefficace è un fenomeno frequente; l'uso dell'ossitocina per accelerare il travaglio è controverso, soprattutto per la relativa difficoltà di monitorare en-trambe i gemelli in maniera soddisfacente. Inoltre, non esiste consenso su quale sia l'in-tervallo di tempo ideale tra il parto del primo gemello e quello del secondo. Uno dei motivi principali delle divergenze di opinioni su quale debba essere la condizione ottimale del travaglio e del parto gemellare, è la relativa bassa incidenza della gravidanza gemellare, fenomeno che, all'interno di ogni singola unità ostetrica, spesso impedisce una analisi statisticamente significativa dei dati. Recentemente è stato proposto un programma computerizzato (PartoSoft) che, oltre alla raccolta e alla analisi statistica dei dati, permette la visualizzazione e la stampa del partogramma costruito dal computer sulla base degli eventi del travaglio e del parto precedentemente immessi nella banca dati. Il programma prevede una immissione dati specifica per il travaglio ed il parto gemellare. Con la modalità “partogramma multiplo” è possibile visualizzare e quindi studiare contemporaneamente decine di curve relative ad altrettanti travagli gemellari. In questa maniera si possono correlare le modalità di travaglio e parto a numerosi parametri clinici: parità, dilatazione cervicale all'inizio del travaglio, stato delle membrane, uso dell'ossitocina, situazione e presentazione, tipo di analgesia, indicatori di benessere alla nascita (punteggio di Apgar, equilibrio acido-base sui funicoli ombellicali) e pesi alla nascita con percentili.L'adozione di questo programma su scala nazionale permetterebbe la centralizzazione e l'analisi dei dati relativi ai 6000-7000 travagli e parti gemellari che si verificano ogni anno in Italia permettendo di rispondere in modo scientifico ai numerosi quesiti ancora irrisolti.
Incidence and Neonatal Mortality of Twins: Italy 1981-90
Authors: Pugliese A. , Arsieri R. , Patriarca V. , Spagnolo A. 
Published: July 2016

AbstractThe aims of this study were: 1) to study the characteristics of birth and neonatal mortality (NM) rates of twins as compared to singletons in recent years in Italy; 2) to evaluate NM rate differences among twins and singletons by birthweight: 3) to calculate the cause-specific NM rates among singletons and twins. Data concerning all live-born infants were obtained from the birth and death records of the Italian Institute of Statistics (ISTAT) for the years 1981, 1985, 1989 and 1990 and were analyzed by the Statistics Office of the Italian National Institute of Health. Between 1981 and 1990 the incidence of twins increased from 18.3 to 19.1 per thousand livebirths. This increase was mainly related to twins resulting from multiple pregnancies, thus, the proportion of twins weighing < 1500g also increased from 67 to 77 per thousand. Twins accounted for 10% of overall neonatal mortality in 1981 and 14% in 1990. Between 1981 and 1990 in the Centre-South of Italy the crude NM rates showed a greater decrease among singletons than among twins, while in the North the decrement involved both singletons and twins. The birthweight-specific NM rate showed a steady improvement in survival for twins rather than for singletons in the 1500-2499g weight range. Taking each cause of death in 1989-90, NM rates were considerably higher for twins compared to singletons, Twin mortality risks due to newborn respiratory distress syndrome (RDS) and asphyxia were respectively 11 and 8 times that of singletons. The comparison between twin NM rates in the three geografical areas and in relation to the cause of death indicated a greater incidence of RDS and asphyxia in the Centre-South than in the North.This study offers indications on the planning of perinatal care in order to improve twin survival in the Centre and South of Italy, particularly with regard to the prevention and care of asphyxia-RDS.
Genetic and Environmental Effects on Blood Cells
Authors: Colletto G.M.D. Dal , Fulker D.W. , Barretto O.C. de O. , Kolya M. 
Published: July 2016

AbstractIn a sample of 105 concordant sex MZ and DZ twin pairs, the following characteristics were measured: red cell count, haemoglobin concentration, package cell volume, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration, reticulocytes, platelets, white cell count and the six types of leucocytes, lymphocytes, monocytes, band and segmented neutrophils, eosinophils and basophils. The statistical model employed in the univariate twin analysis allows for three sources of variation: genetic (h2), shared environmental (c2) and specific environmental influences (e2). A genetic component was significant for red cell count, haemoglobin and mean cell haemoglobin (0.64, 0.60 and 0.46 respectively), with heritable variation suggested for package cell volume, mean cell volume, mean cell haemoglobin, lymphocytes and monocytes. Shared environmental variation was only present for neutrophils.
Conjoined Twins - An Epidemiological Study Based on 312 Cases
Authors:   The International Clearinghouse for Birth Defects Monitoring Systems
Published: July 2016

AbstractData on conjoined twins have been collected from 14 different malformation monitoring programs around the world. Among over 28 million births, 312 cases were identified. After considering underascertainment in one large program, the best estimate of the incidence based on the sum of induced abortions and births is 1.3 per 100,000 births. The distribution according to type of twinning, the sex distribution (39% males) and the stillbirth rate (47%) are presented. The presence of malformations not directly related to the area of fusion is discussed. In three women, thyroid disease was present and five women had been treated for infertility before conception.
The Definition, Diagnosis, and Management of Growth-Discordant Twins: An International Census Survey
Authors: Blickstein I. 
Published: July 2016

AbstractIn order to establish a protocol considering the definition, diagnosis, and management of growth-discordant twin gestations, a questionnaire was sent to 96 authors of twin-related obstetric articles. The views of the 61 responders comprise this international census survey. The data suggest that a clear cut-off value for discordancy is still needed; however, the data indirectly supported a two-grade definition, namely, mild (> 15% and < 25% birth-weight disparity) and severe (> 25%) growth discordants. Expectant management was advocated by the majority of participants with out-patient follow-up for mild discordants, while severe discordants may preferably be hospitalized. Follow-up should be done by non-stress testing (daily - 2/wk), biophysical profile (1-2/wk), Doppler velocimetry (1/wk - bi-weekly) and sonographic biometry (bi-weekly). The opinions considering termination of pregnancy because of intertwin growth discordancy were divided; however, discordancy per se, was not considered an indication for cesarean delivery. An adapted management flowchart that summarizes the survey's data is presented and may be used as a standard for future investigations.
Higher Order Multiple Births: Natural Wonder or Failure of Therapy?
Authors: Grützner-Könnecke H. , Grützner P. , Grützner B. , Grützner U. , Spalding-Grützner A. , Spalding P. 
Published: July 2016

AbstractData of 601 families with triplets and higher multiples have been collected. Since about nine years the number of higher-order births has been increasing enormously. The average pregnancy duration and the average birthweight of these mostly premature children have been declining from year to year. Despite the progress in neonatology, the death rate and the rate of handicapped children is very high. To prevent such disastrous outcomes, treatments for infertility should be performed only by physicians in centers with strong controls. Selective abortions are no regular solution to the problem of higher multiple gestation.
The End of Reproductive Life in Mothers of Twins: Epidemiologic Analysis of a Large Data Base
Authors: Philippe P. 
Published: July 2016

AbstractA case-control study was conducted on the termination of menstrual life on mothers of twins. It involves a much larger data base and finer analyses, and makes use of the same methodology of a previous study. The time interval between the twin and the last confinement proved to be shorter in twin-bearing mothers than in a matched set of controls with singletons only after blocking of the effect of birth order, and despite the similarity of maternal age at delivery and confinements numbers. Mothers of like-sex twins only appeared to terminate reproductive life earlier than controls. The separate study of maternal age at twin confinement shows that the earlier the twin birth the shorter the menstrual life thereafter. Both like-sex twin births and early maternal age at delivery of a twin pair have the same shortening effect on subsequent menstrual life without clear evidence of additivity of effects as if both occurrences were alternatives with similar biological effects. Comparison of the results of the current study with those of our earlier analysis shows consistency on above results. However, the current study could not reproduce previous results on the role of unlike-sex twins or late maternal age at delivery on time to last confinement; yet, they cannot be discarded. It is suggested that increased power of interaction analyses and tighter matching of controls with respect to sex might improve the conclusions of subsequent studies.
Perinatal Mortality in Twins, Australia, 1973-1980: I
Authors: Doherty John D.H. 
Published: July 2016

AbstractThe perinatal outcome of twin births in Australia is described from 1973 to 1980. Over that period, the perinatal mortality rate declined more slowly in twins that singletons. The stillbirth rate actually increased in twins due to a rise in antepartum deaths. An increasing proportion of monozygotic twins may have contributed to this trend. The overall perinatal mortality rate was 82.85/1,000 for twins and 16.49/1,000 for singletons, giving a relative risk of 5.0.
The Epidemiology of Conjoined Twins in Latin America
Authors: Castilla E.E. , Lopez-Camelo J.S. , Orioli I.M. , Sánchez O. , Paz J.E. 
Published: July 2016

AbstractTwenty–three cases of symmetrical conjoined twins were registered by the Latin-American Collaborative Study of Congenital Malformations (ECLAMC) in 1,714,952 births, which were observed during the 1967-1986 period in 95 maternity hospitals distributed in eleven Latin-American countries. This results in a birth prevalence rate of about 1/75,000 births. The secular and geographic distribution of this material do not depart from random in spite of one hospital with three cases, and two hospitals with two cases each, within a short time period. These 23 cases include one diprosopus, 3 dicephalus, one ischiopagus, 5 pygopagus, none dipygus, 3 syncephalus, none craniopagus, 9 thoracopagus, one omphalopagus, and none rachipagus. Sex distribution is even, with 12 male and 11 female cases.
The Northwestern University Twin Study. V: Twin Deliveries at Prentice Women's Hospital and Maternity Center, 1978-83
Authors: Keith L.G. , Depp R. , Method M.W. , Wittman R. , Lopez-Zeno J. , Minoque J. , Nearhing R. , Keith D.M. 
Published: July 2016

AbstractTwo hundred fifty-one twin deliveries between January 1, 1978 and June 30, 1983 at Prentice Women's Hospital and Maternity Center were reviewed. Cases were excluded if birth weight was less than 500 g, if gestational age was less than 26 weeks or if an antenatal fetal demise had occurred. Maternal demographic characteristics, delivery data and infant characteristics are described. The effect of providing care to a high-risk population of mothers in whom approximately 60% either deliver thair infants preterm or with a birth weight of less than 2,500 g is discussed in terms of costs of care.
Perinatal Deaths in Twin Pregnancy: A 22-Year Review
Authors: Lumme R.H. , Saarikoski S.V. 
Published: July 2016

AbstractChanges in the management of 1120 twin pregnancies delivered in Tampere University Central Hospital during the years 1964-1985 were studied, together with changes in the pattern of perinatal deaths. Perinatal mortality decreased from 7.4% in 1964-68 to 3.5% in 1981-85. There were no significant changes in stillbirths. The decrease of perinatal mortality resulted from a reduction in early neonatal deaths, mainly those due to respiratory distress syndrome. Changes in obstetric management include earlier diagnosis by ultrasound, intrapartum monitoring, and an increase in cesarean section rate from 4% to 32%. There is still a need for a reduction in the number of very early preterm births, and for more effective intrauterine supervision of twin pregnancies.
The Northwestern University Triplet Study. II: Fourteen Triplet Pregnancies Delivered between 1981 and 1986
Authors: Keith L.G. , Ameli S. , Depp O.R. , Hobart J. , Keith D.M. 
Published: July 2016

AbstractFourteen triplet deliveries conducted between 1 January 1981 and 30 June 1986 at the principal teaching hospitals of Northwestern University Medical School are reviewed. Maternal demographic characteristics are listed, as are the obstetric outcomes, including mode of delivery, and the fetal outcome. The recent literature of triplet delivery is reviewed.The rate of triplet delivery in our study was 0.37 per 1,000 live births. About two-thirds of the pregnancies resulted from the use of fertility-inducing agents. Ultrasonic confirmation was available in all cases. The majority of women were delivered by cesarean section (85%). No consistent pattern of presentation was seen. The mean weight of all 42 infants was 1,779 g (± 594). Unlike-sex triplets accounted for most of the sets (77%). The mean 5-min Apgar score of all infants was 9 and had no association with the order of deliveries. The weight differences by sex regardless of birth order were clinically insignificant. Neonatal mortality was 2.3%
The Northwestern University Triplet Study. III: Neonatal Outcome
Authors: Collins J.W. , Merrick D. , David R.J. , Ameli S. , Ogata E.S. 
Published: July 2016

AbstractLimited data suggest that cesarean section (CS) may be the preferred method of delivery for triplets. Despite this, it is also felt that the third triplet is at great risk at delivery. We reviewed our experience of 14 triplet pregnancies at Northwestern University between 1981 and 1985. All deliveries were attended by neonatal teams in sufficient number to resuscitate each infant. Of the 14 pregnancies, two ended in previable loss. Thirty-six infants were born from 12 pregnancies of a mean gestational age of 33 weeks (28-38 weeks). The overall survival was 97.3%. Two women delivered vaginally. While the first was successful, the second resulted in vaginal delivery of the first two triplets followed by emergency CS for the third. That infant had a cord blood pH of 6.96(BE-19), was resuscitated and survived. All 10 CS were successful. The mean cord blood gas tensions and pH were normal. In addition, Apgar scores, the requirement for mechanical ventilation or supplemental oxygen, and mortality did not differ between the first and thirdborn triplet. These observations suggest that CS was beneficial. Our very low mortality rate supports the concept that CS delivery and aggressive neonatal resuscitation and therapy greatly enhances survival.
Growth Characteristics in Twins and Higher Order Multiple Births
Authors: Buckler J.M.H. , Buckler J.B. 
Published: July 2016

AbstractMeasurements of height and weight have been undertaken on 201 pairs of twins and 46 sets of higher multiples once each at various ages through childhood. The heights of twins are comparable to the overall population of singletons, those of higher multiples are slightly undersized. However, the total group of twins were shorter than expected when compared with the heights of parents and siblings, but this was entirely accounted for by that component of the group who at birth had been very light for dates. The children in all groups of multiples were underweight for their height in comparison with standards of a comparable population and with their own siblings.