Baseline frequency of sister-chromatid exchanges in 142 persons of the general Korean population.

Baseline frequencies of sister-chromatid exchange (SCE) were measured in lymphocytes of 142 healthy Koreans ranging in age from newborn infants to the fifties. The overall mean frequency of SCE was 8.78 +/- 0.24/cell. However, highly significant differences were found between individuals. The mean SCE values of the newborn babies and small children less than 10 years old were significantly lower than those of other age groups. No age effect was, however, observed in adolescent and adult subjects. Females had statistically higher SCE levels than males. The mean SCE frequencies of smokers, measured in male subjects more than 10 years old, were slightly, but statistically significantly, higher than those of non-smokers.     

Cytogenetic analysis in workers occupationally exposed to nickel carbonyl

Chromosomal aberration and sister-chromatid exchange (SCE) base-line frequencies and SCE frequencies induced by 10 ng/ml mitomycin C (MMC) were analysed in cultured peripheral lymphocytes of 65 workers occupationally exposed to nickel carbonyl Ni(CO)4. The subjects were divided into 4 groups: (1) control; (2) exposed to nickel carbonyl (= exposed); (3) cigarette smokers; (4) smoking-exposed. The results show that there are no significant differences in chromosomal aberration frequencies, breaks or gaps, between the various groups. However, the SCE base-line frequency of the smoking-exposed group, with an average of 7.7/cell, was significantly higher than that of the control group, with an average of 6.5/cell (P less than 0.01), and also than that of the exposed group with an average of 5.9/cell (P less than 0.01). Similarly, the SCE frequency induced by 10 ng/ml MMC in the smoking-exposed group which averaged 15.5/cell was significantly higher than that of the control group (average of 13.2/cell (P less than 0.05], and also than that of the exposed group with an average of 12.3/cell (P less than 0.01). Under our experimental conditions, it may be that the level of exposure was not high enough to elicit an increase in chromosomal aberrations and SCE frequencies in the non-smoker exposed group. The fact that an increase in SCE frequencies was only found in the smoking-exposed group implies that the two factors, smoking and exposure to nickel carbonyl, are jointly responsible for the result.     

Epidemiological features of some acute inflammatory morbid conditions in the neonatal period

In this study, medical records of 231 Prague, Czechoslovakia and 234 Moscow, USSR newborn infants treated for various forms of acute inflammatory diseases acquired in the neonatal period, i.e. during both hospital stay and home nursing period, were reviewed with the aim of assessing the epidemiological characteristics of these morbid conditions. As shown by the analysis of available epidemiological data, most of these inflammatory disease, both in Prague and Moscow, occurred shortly after birth, with a peak at 7 postnatal day, which pointed to hospital stay as a decisive factor in the onset of neonatal inflammation. In Prague, the overall number of inflammation cases diagnosed within the first decade of postnatal days was about three time the number recorded during the second decade; the respective figures for Moscow infants were in both decades identical. Assessed by clinical forms of inflammation, both groups of newborn infants showed concordance for conjunctivitis only (28%), frequencies of other clinical forms varied. In Moscow, the most common form of inflammation, predominant over all other clinical forms especially in the second decade, was pyoderma (29%), followed by conjunctivitis (28%), phlegmon (13%) and gastroenteritis (13%). Cases of gastroenteritis, acquired mostly during the home nursing period, were hospital-unrelated and predominated in the last decade of neonatal life. In the Prague group of infants, cases of catarrhal omphalitis were predominant, accounting for 37% of all diseases; this was due to a local outbreak of epidemic at the time of observation. The frequency of pyoderma, phlegmon and gastroenteritis was here lower than that among the Moscow infants, situation with the inflammation cases classed as "other diseases" was opposite.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of styrene oxide on chromosome aberrations, sister chromatid exchange and hepatic drug biotransformation in chinese hamsters in vivo

In vivo inhalation exposure to styrene oxide (25, 50, 75 and 100 ppm) for 2, 4 or 20 days (25 ppm only) had no effects on chromosomal aberration rates or sister chromatid exchange (SCE) frequencies (BrdU/labelling performed in vitro) in the bone marrow cells of Chinese hamsters. The only positive response in aberration frequency was obtained when styrene oxide was injected in lethal concentration (500 mg/kg body weight, i.p.) into the animal. One animal out of six showed slightly elevated SCE values after this high dose. The response of the hepatic drug metabolizing enzymes to styrene oxide exposure was found to be rather weak, which may be due to rather high activity of epoxide hydratase in Chinese hamsters as compared to e.g. mouse.     

Sister-chromatid exchanges in lymphocytes from infants with Down's syndrome

Sister-chromatid exchange (SCE) frequencies were studied in blood lymphocytes from 12 patients (3 females and 9 males) with Down's syndrome (DS). The mean frequency of SCE per metaphase for the patients (both sexes) was 9.2 +/- 0.8 which was significantly higher (P less than 0.01) than the mean SCE value (5.1 +/- 0.2) scored for 16 healthy infants (8 females and 8 males). A significant increase in the mean frequency of SCE in 12 parents of infants with DS (8.7 +/- 0.9 SCE/cell) was noticeable when compared with 20 parents of normal infants (6.3 +/- 0.1 SCE/cell). Increases in cellular division with reduction in their replication were also observed in patients with DS. Treatment with mitomycin C (0.05 micrograms/ml), hycanthone (0.1 micrograms/ml) and gamma-radiation (0.1 Gy) revealed a significant (P less than 0.01) increase in frequencies of SCE in DS lymphocytes and in those of their parents as compared to controls. These data may reveal a familial hypersensitivity reaction to these agents. The results indicate a genomic instability and deranged DNA-repair mechanisms which are accentuated by exposure to mutagenic agents, the underlying causal factor for which might be genetic.     

Ataxia telangiectasia: the effects of chemical mutagens and x-rays on sister chromatid exchanges in blood lymphocytes

It is now possible to examine in detail exchanges between sister chromatids (SCEs) and to attempt to investigate the relationships of such exchanges to aberration formation and DNA-repair mechanisms. The frequency of SCEs is dramatically increased by chemical mutagens and may reflect the level of DNA damage. Lymphocytes from patients with ataxia telangiectasis (AT) show high levels of spontaneous chromosome damage and are hypersentive to ionising radiations and it was of interest to examine the levels of SCE induced in these cells by various mutagens. The frequencies of SCE after treatment with X=rays or three chemical mutagens were equivalent to those in normal cells. The effects of fluorodeoxyuridine and deoxycytidine on SCE frequencies were also tested.     

Chromosome aberrations in individuals occupationally exposed to ethylene oxide, and in a large control population

Chromosome aberration frequencies in 61 employees potentially exposed to ethylene oxide (ETO) were compared with those in unexposed control groups. We studied 3 worksites with differing historical ambient levels of ETO. Within worksites, groups were classified as high potential exposed, low potential exposed, or controls. Further control groups including an off-site community control group were added to give a total of 304 control individuals. Blood samples were drawn several times over a 24-month period. Aberrations were analyzed in 100 cells per sample after culture for 48-51 h. Worksites I, II and III respectively represented increasing levels of potential ETO exposure. At worksites I and II, no consistent differences in aberration frequencies were found among groups. At worksite III aberration frequencies in potentially exposed individuals were significantly increased compared with controls. The frequencies of cells with aberrations were 5.6% for the 2 individuals in the high potential exposure category and 2.6% for 23 persons in the low potential exposure group. The overall frequency of cells with aberrations in the matched control individuals was 1.4%. In the total control group of 304 individuals we found significant increases in aberrations associated with smoking and with increasing age. We have also reported previously an association between sister-chromatid exchange (SCE) frequency and ETO exposure (Stolley et al., 1984). When aberration frequencies were compared with levels of SCEs there was only a weak overall association. The correlation was found in potentially exposed but not in control groups, and for any individual, one observation could not be used to predict the other.     

Altitude and infant growth in Bolivia: A longitudinal study

The growth of 79 healthy, well-nourished lowland (400 M) and highland (3600 M) Bolivian infants was analyzed in a longitudinal study through the first postnatal year. Compared to low altitude infants, the high altitude infants were found, by analysis of covariance controlling for size at the previous exam, to be significantly shorter at birth, 1 and 6 months, while they were significantly lighter only at birth and 1 year. Recumbent length gain was slower in the high altitude infants in the early months of life, while weight gain did not differ between altitudes. The observed lower weights at high altitude throughout the first year appear to be due to a persistence of lower weights seen at birth and not to postnatal growth retardation. Significantly greater triceps and subscapular skin-fold thickness measurements were found in the highland group, despite their smaller length and weight. The possible causes and implications of the greater fat accumulation in the highland infants are discussed.     

Isolation of females prior to parturition reduces neonatal mortality in Galago

Eighteen years of birth records for three species of Galago at the Duke University Primate Center were examined to determine the effects of isolation of pregnant females on neonatal mortality rates. Isolation significantly decreased neonatal mortality rates in all three species over neonatal mortality rates in infants born to unisolated females. The frequency of cannibalism of infants did not differ between isolated and unisolated females. Secondary sex ratio differed significantly from 1:1 for all three species, but higher mortality in males in the first 10 days of life resulted in sex ratios that did not differ from 1:1 in G. garnettii and G. crassicaudatus.     

Analysis of ethnic differences in perinatal statistics.

The 3996 mothers delivered at Dudley Road Hospital, Birmingham, in 1979 were analysed for their ethnic origins. Social classes IV and V predominated in all groups. A high proportion of Indian mothers fell into the low-risk group based on age and parity but had the highest stillbirth and perinatal mortality rates (15.1 and 27.5/1000 respectively) and infants of low mean birth weight (2986 g). Elderly and multiparous mothers were characteristic of the Pakistani and Bangladeshi groups. Young, primiparous mothers were more common among the West Indians and Europeans, in whom the stillbirth and perinatal mortality rates were low; infants in the European group had a mean birth weight higher than in any other group (3231 g). From these findings ethnic origin of the mother is apparently an important factor in perinatal mortality.     

Parameters of Surface Electromyograms in Full-Term and Preterm Infants in the Neonatal Period: The Possible Contribution of Gravity

The purpose of this study was to compare the postnatal evolution of spectral–amplitude and nonlinear parameters of surface electromyogram (sEMG) in the full-term and preterm infants with regard to their biological and calendar age. In full-term infants, all sEMG parameters (dimension, entropy, mean frequency, and amplitude) are increased by 10–30% two weeks after birth. On the contrary, sEMG parameters in preterm infants were constant for six weeks after birth. This finding indicates that both postnatal and antenatal periods are important for the development of the motor system of infants. Therefore, the adaptation of the motor system to extrauterine conditions consists of two stages. The authors suppose that gravity can be a driving factor of these sEMG metamorphoses.     

Use of oxytocin and incidence of neonatal jaundice.

A retrospective controlled study using data from the Cardiff Births Survey examined a possible relation between oxytocin administration to induce or accelerate labour and the subsequent development of neonatal jaundice. Among 10 591 infants born in Cardiff between 1970 and 1972 the incidence of neonatal jaundice was higher in infants born after oxytocin administration than among others. Analysis by gestational age at delivery, birth weight, Apgar score, length of labour, sedative and analgesic therapy during labour, and suppression of lactation showed that this association held within all these categories except among small immature infants, who are at high risk of jaundice in any case.     

Rapid recovery of fat mass in small for gestational age preterm infants after term

Background

Preterm small for gestational age (SGA) infants may be at risk for increased adiposity, especially when experiencing rapid postnatal weight gain. Data on the dynamic features of body weight and fat mass (FM) gain that occurs early in life is scarce. We investigated the postnatal weight and FM gain during the first five months after term in a cohort of preterm infants.

Methodology/Principal Findings

Changes in growth parameters and FM were prospectively monitored in 195 infants with birth weight ≤1500 g. The infants were categorized as born adequate for gestational age (AGA) without growth retardation at term (GR−), born AGA with growth retardation at term (GR+), born SGA. Weight and FM were assessed by an air displacement plethysmography system. At five months, weight z-score was comparable between the AGA (GR+) and the AGA (GR−), whereas the SGA showed a significantly lower weight.The mean weight (g) differences (95% CI) between SGA and AGA (GR−) and between SGA and AGA (GR+) infants at 5 months were −613 (−1215; −12) and −573 (−1227; −79), respectively. At term, the AGA (GR+) and the SGA groups showed a significantly lower FM than the AGA (GR−) group. In the first three months, change in FM was comparable between the AGA (GR+) and the SGA groups and significantly higher than that of the AGA (GR−) group.The mean difference (95% CI) in FM change between SGA and AGA (GR−) and between AGA (GR+) and AGA (GR−) from term to 3 months were 38.6 (12; 65); and 37.7 (10; 65). At three months, the FM was similar in all groups.

Conclusions

Our data suggests that fetal growth pattern influences the potential to rapidly correct anthropometry whereas the restoration of fat stores takes place irrespective of birth weight. The metabolic consequences of these findings need to be elucidated.     

In vivo mutant T cell frequency in atomic bomb survivors carrying outlying values of chromosome aberration frequencies

Frequencies of HPRT- mutant T cells were determined by means of a direct clonal assay in atomic bomb survivors who showed outlying values of chromosome aberration frequencies. The studied survivors consisted of 2 groups: those whose aberration frequency was near the higher end of the distribution (high-aberration group) and those whose aberration frequency was near the lower end of the distribution (low-aberration group). The mean radiation doses (T65D) of the high-aberration group (13 people) and low-aberration group (17 people) were 248 and 273 rad, respectively. The mean mutant frequency (Mf) of the high-aberration group was 6.7 X 10(-6), which was significantly higher than that of the low-aberration group (3.7 X 10(-6)) or that of 17 controls (3.4 X 10(-6)). When all the samples were combined, the correlation between Mf and radiation dose was not significant using either dose estimation system, T65D or DS86. However, the correlation coefficient was higher when DS86 doses were used. Mf correlated significantly with increasing aberration frequencies. The tendency that Mf correlates better with chromosome aberration frequency than with estimated radiation dose was stronger in this study than in a previous study where the samples were selected randomly.     

Serum bilirubin levels in breast- and formula-fed infants in the first 5 days of life.

A prospective study was conducted in a level II maternity unit to investigate the incidence of hyperbilirubinemia in healthy, term, breast-fed and formula-fed infants. Serum bilirubin levels were determined for 176 breast-red and 164 formula-fed infants in cord blood and on days 1, 2, 3 and 5 after birth. The mean total bilirubin levels were significantly higher on each postnatal day in the breast-fed infants, as was the proportion of infants with peak levels above 12 mg/dl (205 mumol/l; 28% v. 6%). The breast-fed infants also had significantly higher proportional weight losses on each postnatal day than the formula-fed infants. However, there was no correlation between the cumulative weight loss on day 3 and bilirubin levels on the same day with either feeding regimen. None of the infants required an exchange transfusion or prolonged care in hospital for hyperbilirubinemia.     

The influence of birth timing upon infant growth and survival in Captive Rhesus Macaques (Macaca mulatto)

Weights, growth rates, and mortality data of 815 captive-born Macaca mulattainfants were studied to determine if date of birth influences infant growth and survival. The six groups studied displayed a unimodal spring-summer birth season that has become systematically more restricted since 1977. Males exhibited higher rates of stillbirth and neonatal death and were more frequently born outside the normal birth season, when infant mortality was more common. Within the normal birth season, infant weight increased linearly with birth date, and infant growth rate declined linearly with birth date. Female infants with weights and growth rates near the developmental norm, especially those born in the middle of the birth season, have the greatest probability of survival. Males are more likely to survive if their weights and growth rates exceed the developmental norm, and thus male infants might be initially more costly to produce than female infants. These results are inconsistent with the hypothesis that offspring of high-ranking males, which conceived predominantly in the first third of the breeding season, enjoy a selective advantage.     

Variation in early neonatal mortality for different types of fetal growth retardation

Birth and first-48-hr death records were analyzed for 10,024 liveborn infants in Mexico City and 12,786 liveborn infants in Santa Cruz, Bolivia. The objective of the analysis was to characterize the early postnatal mortality rates for different types of fetal growth retardation and prematurity. Infants who were delivered prior to 37 weeks of gestation had 23-100 times the mortality risk of infants born at full term and normal weight. Light-for-gestational-age infants (birth weight less than 2,900 g) were further divided into proportionately growth-retarded with normal Rohrer's index (weight/height) and disproportionately growth-retarded with low Rohrer's index. The proportionately growth-retarded infant had nearly twice the mortality of the full-term, appropriate-weight infants, whereas the disproportionately growth-retarded infants had 2.9-5.7 times the mortality rate of the full-term, appropriate-weight infants. There were some differences between samples in mortality rates and prevalence of the different classes of small infants, but the pattern of mortality within samples was consistent between samples.     

Contribution of preterm delivery to perinatal mortality.

A detailed retrospective analysis was made of the records of 486 preterm infants, who accounted for 5-1% of all births during 1973 and 1974. Whereas preterm delivery did not contribute to perinatal mortality in terms of stillbirth, it outweighed all other causes in terms of early neonatal deaths. Preterm birth was responsible for 85% of the early neonatal deaths not due to lethal congenital deformities. Early neonatal mortality rates were closely linked both to gestational age and birth weight and to the reason for preterm birth. Early neonatal mortality was high (97 per 1000) when preterm labour was spontaneous, whether or not associated with material or fetal disease or with multiple pregnancy, but low (27 per 1000) when preterm delivery was elective. Preventing spontaneous preterm labour would considerably reduce neonatal mortality in our community.     

Premature baby statistics.

For 27 years annual figures have been kept of all infants weighing 2500 g or less born in the maternity department of the Northern General Hospital, Sheffield. The initial neonatal mortality rate (death within the first four weeks after birth) was then around 30% and is now 10%. This reduction is partly due to a decreased mortality rate among the individual weight groups but also to an increasing number of larger infants and a decreasing number of infants of low birth weight in the "high-risk" category.