Yoshie Yokoyama

Highly nucleophilic tributyltin azide in oxirane ring cleavage leading to 1,2-azido alcohol

Abstract Enhanced reactivity of tributyltin azide has been demonstrated in nucleophilic ring cleavage of oxiranes without solvent and promoter to give 1,2-azido alcohols in good to excellent yields.

Breastfeeding rates among singletons, twins and triplets in Japan: A population-based study.

This study was performed to determine the rates of breastfeeding among singletons, twins and triplets in Japan, and identify factors associated with the decision to breastfeed or bottle-feed. We analyzed a database of medical check-up of infants aged 3 to 6 months between April 2001 and July 2004 in Nishinomiya City in Japan. This medical check-up is given to almost 100% of infants in Japan and the data of 15,262 infants were analyzed. Among these, 14,963 (98.0%) were singletons, 290 (1.9%) were twins and 9 (0.1%) were triplets. Exclusive breast-feeding was chosen by 6680 (43.8%) mothers, mixed-feeding by 4645 (30.4%) mothers, and bottle-feeding with formula milk only by 3900 (25.6%) mothers. The rate of exclusive breastfeeding among twins or triplets was significantly lower than among singleton babies: 4.1% among twins or triplets, and 44.7% among singletons. Moreover, twins and triplets were independently associated with a higher rate of bottle-feeding: the odds ratio indicated that mothers who had twins or triplets were 2.44 times more likely to choose bottle-feeding with formula milk only than those who had singletons. Sucking ability at birth was associated with a higher rate of bottle-feeding: the odds ratio indicated that mothers who had infants with poor sucking ability at birth were 1.56 times more likely to choose bottle-feeding as those who had infants with normal sucking ability.

Comparison of Child-rearing Problems Between Mothers with Multiple Children who Conceived after Infertility Treatment and Mothers with Multiple Children who Conceived Spontaneously

The purpose of this study was to clarify the characteristic child-rearing problems for mothers of multiple children who conceived after infertility treatment as compared to mothers of multiple children who conceived spontaneously. The subjects were 990 mothers of multiple children: 359 who conceived after infertility treatment and 631 who conceived spontaneously. Mothers who conceived after infertility treatment were more delighted when informed of a multiple pregnancy than those who conceived spontaneously. In addition, with respect to anxiety during twin pregnancies, mothers of twins who conceived after infertility treatment showed lower rates of anxiety about nursing the infants and economic concerns than those of twins who conceived spontaneously. However, after delivery, mothers who conceived after infertility treatment showed a higher rate of depressive symptoms than those who conceived spontaneously. After adjusting for each associated factor using logistic regression, the risk of depressive symptoms in mothers who conceived after infertility treatment was significantly associated with disabled multiple children and the methods for alleviating stress. The odds ratio indicated that mothers with at least one disabled child were twice as likely to have depressive symptoms as mothers with no disabled children. Furthermore, the odds ratio indicated that mothers who used no methods for alleviating stress were twice as likely to have depressive symptoms than those who did.

Fundal Height as a Predictor of Early Preterm Triplet Delivery

The purpose of this study was to create graphs of fundal height parameters in triplet pregnancies compared with those in twin pregnancies, and to investigate whether larger fundal heights in triplet pregnancies would predispose them to earlier delivery (before 34 weeks). The subjects were 727 twin pregnant women and 133 triplet pregnant women, who delivered after 1984. Triplet pregnancies showed significantly higher fundal heights compared with twin pregnancies at each gestational age (weeks). In triplet pregnancies, a single fundal height measurement above the 90th percentile before 34 weeks yielded a sensitivity of 31.3% and specificity of 82.4% for delivery before 34 weeks, with a positive predictive value of 50.0% and a negative predictive value of 68.0%. After adjusting for each associated factor using logistic regression, the risk of preterm labour was not significantly associated with a single fundal height measurement above the 90th percentile recorded before 34 weeks.

Analysis of Factors Affecting Birthweight, Birth Length and Head Circumference: Study of Japanese Triplets

The aims of this study were to identify factors associated with birthweight, birth length and head circumference for triplets, and analyze these body size parameters at birth, especially head circumference, according to gestational age. The subjects of this study were 370 mothers and their 1109 triplet children (excluding one stillborn infant) who were born between 1978 and 2002. The gestational age proved to be the strongest contributing factor to birthweight, birth length and head circumference of the triplets. Moreover, sex was a significant factor affecting birthweight, birth length and head circumference. Male neonates had a higher birthweight, longer birth length and greater head circumference than female neonates. Birth order in triplets also had a significant effect on birthweight and head circumference. Lower birth-order neonates had a higher birthweight and greater head circumference. An effect of maternal pregravid body mass index (BMI) on both birthweight and birth length was observed. The birthweights of triplets born to women whose pregravid BMIs were more than 26.0 kg/m2 weighed an average of 150 g more than those of triplets born to women whose pregravid BMIs were less than 19.8 kg/m2, and the birth length of triplets born to women whose pregravid BMIs were more than 26.0 kg/m2 averaged 1.5 cm longer than those of triplets born to women whose pregravid BMIs were less than 19.8 kg/m2. Concerning head circumference, the median head circumference of male neonates was approximately 0.5 cm longer than female neonates. Compared to singleton neonates, the median head circumference of triplets was almost the same.

Activities and Health Status of Dispatched Public Health Nurses after the Great East Japan Earthquake

Objective This study aimed to elucidate the actual activities conducted by public health nurses during their dispatch and their health status during and after dispatch to the three prefectures most severely affected by the Great East Japan Earthquake. Sample A survey request was sent to a total of 2,237 facilities. Of these, 778 facilities returned questionnaires from dispatched public health nurses. Results The participants of this study were 1,570 dispatched health nurses who participated in activities mostly at evacuation centers, followed by evacuees’ homes. After dispatch, an earlier postdisaster phase at the start of dispatch was independently associated with poor subjective well-being, low mood, worsened sleep state, and intense fatigue. Work hours per day were associated with poor subjective well-being and intense fatigue after dispatch. Conclusion Results suggest that the factor that most strongly affected the postdispatch health of the nurses was the phase that they began their dispatch.

Weight growth charts from birth to 6 years of age in Japanese triplets

We analyzed the characteristics of weight growth and present the weight growth charts from birth to 6 years of age in Japanese triplets. The study included 366 mothers and their 1098 triplet children, who were born between 1978 and 2006. Data were collected through a mailed questionnaire sent to the mothers asking for information recorded in medical records. For these births, data on triplets weight growth, gestational age, sex, parity, and maternal age at delivery were obtained from records in the Maternal and Child Health Handbooks, which is provided by the authorities after a report of pregnancy. Birthweight proved to be the strongest contribution on weight of triplets from 1 to 6 years of age. In addition, gestational age was also a significant contributing factor to weight from birth to 6 years of age. Moreover, males had a higher weight from birth to 6 years of age than females. Compared to the 50th percentile of the growth standard for the general population of Japan, the weight deficit of the triplets was more than 40% at birth (male, -1.28 kg; female, -1.28 kg), decreased within the first 1 year of age, and fluctuated between 4% and 9% until 6 years of age (male, -1.82 kg; female, -1.78 kg). In conclusion, triplets have lower birth weight than singletons and in spite of the rapid catch-up growth during first year of life they are behind singletons even in mid-childhood. This study provides growth curves for use in triplets.

Height Growth of Triplets from Birth to 12 Years of Age in Japan

We analyzed the characteristics associated with the growth in height of Japanese triplets from birth to 12 years of age. The study included 376 mothers and their 1,128 triplet children, who were born between 1978 and 2006. Data were collected through a mailed questionnaire sent to the mothers asking for information recorded in medical records. For these births, data on triplets length and height growth, gestational age, sex, parity, maternal age at delivery, and maternal height were obtained from records in the Maternal and Child Health Handbooks and records in the school which children receive health check-ups. The height deficit of the triplets compared to the general population of Japan remained between 2% and 5% until 12 years of age. Moreover, at 12 years of age, the differences of height between the general population and triplets were approximately -3.6 cm for male and -4.4 cm for female. Maternal height showed the strongest contribution to height of triplets from 6 to 12 years of age. In conclusion, triplets remain shorter than singletons until 12 years of age.

Genetic Regulation of Pre-Pubertal Development of Body Mass Index: A Longitudinal Study of Japanese Twin Boys and Girls

We analyzed the genetic architecture of prepubertal development of relative weight to height in 216 monozygotic and 159 dizygotic complete Japanese twin pairs (52% girls). Ponderal index at birth (kg/m3) and body mass index (BMI, kg/m2) from 1 to 11xa0years of age were used. Additive genetic factors explained the major proportion (52–74%) of the variation of BMI from 1 to 11xa0years of age. Environmental factors common to both co-twins also showed some effect (7–28%), but at most ages this was not statistically significant. Strong genetic tracking was found for BMI from 1 to 11xa0years of age, but there was also evidence for a persistent effect of common environmental factors. Our results suggest that the genetic architecture of BMI development in the Japanese population is generally similar to that found in previous twin studies in Caucasian populations.

Genetic and Environmental Influences on Chest Circumference during Infancy: A Longitudinal Study of Japanese Twins

BACKGROUNDnChest circumference (CC) is suggested to be a good indicator of early life nutrition, but little is known on the heritability of CC. Thus we analysed the effects of genetic and environmental factors on the development of CC in Japanese infants.nnnMETHODSnCC was measured longitudinally from birth until 1 year of age in a cohort of 211 monozygotic and 160 dizygotic complete Japanese twin pairs born in 1989-2002. The data were analysed using applications of structural linear equation modelling for twin data.nnnRESULTSnNo sex-specific differences in the variance components were found. Environmental factors unique to each twin explained the major part of the variation of CC at birth whereas environmental factors shared by co-twins were more important at 1-3 months of age. From 3 months of age, the effect of genetic factors become steadily stronger and they explained the majority of the variation at 1 year of age. Strong genetic continuity in the development of CC was found, but also new sets of genes were activated during the first year of life. The origin of the environmental part of the variation could be tracked before 3 months of age. A substantial part of common and specific environmental factors affecting CC affected also birthweight.nnnCONCLUSIONSnCC is sensitive to intrauterine environmental factors, but these effects diminish during the first year of life, at least if postnatal environment is good. CC can be a useful indicator when identifying newborns who have suffered suboptimal pre-natal conditions.