Prognosis of perinatal brain damage: a prospective study of a one year birth cohort of 12,000 children

Severe mood disorders and schizophrenia in the adult offspring of antenatally depressed mothers in the Northern Finland 1966 Birth Cohort: Relationship to parental severe mental disorder

BACKGROUND

Maternal antenatal depression may alter offspring neurodevelopment, but long follow-up studies are lacking. We studied the risks for mood disorders and schizophrenia in adult offspring of antenatally depressed mothers, taking account parental severe mental disorders.

METHODS

In the general population-based Northern Finland 1966 Birth Cohort with 12,058 children, 13.9% of the mothers reported themselves depressed at mid-gestation. The offspring were followed 43 years. Severe mood disorders and schizophrenia in the offspring and severe mental disorders in the parents were detected using the Care Register for Healthcare. Maternal smoking during pregnancy, perinatal complications, fathers´ social class, family type at birth, and grand multiparity were considered as confounding variables.

RESULTS

The offspring of antenatally depressed mothers had an elevated risk for depression (adjusted OR 1.5; 95% CI 1.03-2.2), compared to cohort members without maternal antenatal depressed mood. The offspring with maternal antenatal depressed mood and parental severe mental disorder had markedly elevated risks for depression (3.3; 1.8-6.2), and schizophrenia (3.9; 2.0-7.5), compared to the offspring without one or both of these risk factors.

LIMITATIONS

Maternal antenatal depressed mood was determined by one question and did not necessarily signify a clinical condition. Data on maternal postnatal mood was not available.

CONCLUSION

The offspring with maternal antenatal depressed mood and parental severe mental disorder had high risk for depression and schizophrenia. Early interventions in parental severe mental disorder might present an opportunity for decreasing the risk for mood disorders and schizophrenia in the offspring.

Volumes of brain, grey and white matter and cerebrospinal fluid in schizophrenia in the Northern Finland 1966 Birth Cohort: an epidemiological approach to analysis

Magnetic resonance imaging (MRI) studies in schizophrenia have seldom involved a general population birth cohort or other epidemiological samples. We studied the Northern Finland 1966 Birth Cohort and identified all people with psychotic disorders. Along with an unaffected age-matched control sample (n = 100) from the cohort, 54 subjects with schizophrenia underwent MRI brain scan at age 33-35 years from which we defined volumes of whole brain, grey and white matter and intracranial cerebrospinal fluid (CSF). Whole brain, grey and white matter volumes were 2-3% smaller in the schizophrenia subjects, who showed a 7% increase in CSF volume. These volume changes were independent of the effects of gender, family history of psychosis, perinatal risks or age at onset of illness. Moreover, there was no evidence that the effects were due to particular subgroups of cases having very low or high values. Rather, there were linear trends in the associations between whole brain and grey matter volume measures and schizophrenia. Our study replicates the previous findings of brain volume differences in schizophrenia on a general population level.

Criminality in the offspring of antenatally depressed mothers: a 33-year follow-up of the Northern Finland 1966 Birth Cohort

BACKGROUND

No epidemiological studies have been reported on the association between mothers' antenatal depression and criminality in their offspring.

METHODS

The material consists of a general population cohort of 12059 children born in 1966 in Northern Finland and followed to the end of 1998. Mothers were asked at midgestation by a nurse at the antenatal clinic if they felt themselves to be depressed. The Finnish Ministry of Justice provided information for all descendants on criminal offences. The associations between maternal depression and subgroups of violent and non-violent, violent recidive and non-recidive criminality in male and female offspring were analysed.

RESULTS

Of the mothers 14% had depressed mood during pregnancy. A total of 607 (10.9%) male and 72 (1.3%) female criminal offenders were included in the cohort. When adjusted for mother's marital status, smoking, wantedness of the pregnancy, place of residence, socioeconomic status and perinatal complications, the odds ratio (OR) for males was 1.4 (95% CI 1.0-1.9) in the association between maternal depression and non-violent offenders, 1.6 (1.1-2.4) between maternal depression and violent offenders and 1.7 (1.0-3.0) between maternal depression and violent recidivists. The adjusted OR for females involved in non-violent crimes was 1.7 (0.9-3.3) and 0.6 (0.1-6.0) for violent crimes.

LIMITATIONS

Maternal depression was not checked using a standardized assessment.

CONCLUSIONS

For male offspring of antenatally depressed mothers there was a significant but slight increase in criminality. The emotional state of a pregnant mother may have some, but limited, influence on later criminality in the offspring.

Predictors of female criminality: findings from the Northern Finland 1966 birth cohort

OBJECTIVE

Females still commit fewer criminal offenses than males, but the percentage of female offending has been increasing during the past few decades. Thus there is a need for original studies into the perinatal contribution to the etiology of female offending.

METHOD

A large, prospectively collected birth cohort database of female members (N = 5,056) was available. Information on perinatal biological and psychosocial risks as well as data from the National Crime Registers up to 32 years of age were collected and analyzed by logistic regression and a chi2 automatic interaction detection (CHAID) analysis.

RESULTS

The absence of the father during childhood was the strongest risk factor in predicting female criminality (odds ratio 2.5; 95% confidence interval 1.4-4.3). Furthermore, in the families in which the father was present, maternal smoking during pregnancy together with being born unwanted correlated with an increased prevalence of criminal offending significantly up to 7.2%.

CONCLUSIONS

CHAID analysis proved to be a useful statistical method in predicting female adult criminality after preceding perinatal risks. It revealed that the risk factors were mainly familial, the paternal factor being the most important one in determining the probability of daughters committing criminal offenses.

Family type and criminal behaviour of male offspring: the Northern Finland 1966 Birth Cohort Study

BACKGROUND

Unstable family environment during childhood is known to predispose to juvenile delinquency.

AIMS

This study explored whether childhood family structure is associated with violent behaviour of adult offspring.

METHODS

We used a large, unselected general population birth cohort (n = 5589 males) linked with the national crime registers (up to the age of 32 years). The Ministry of Justice provided information on registered offences for all subjects. A logistic regression analysis was performed to examine the association between family type and criminality (violent and non-violent crimes).

RESULTS

We found that single-parent family "at birth" (adj. OR 3.6, 95% CI 1.8-7.0) and "all time" (up to the age of 14 years) (adj. OR 5.2, 95% CI 2.5-10.6) were risk factors for violent offences of an adult offspring. Also parental death (adj. OR 2.2, 95% CI 1.3-3.6) and divorce (adj. OR 2.5, 95% CI 1.6-3.7) doubled the risk for violence. Non-violent offences were associated only with parental death and, divorce.

CONCLUSIONS

A single-parent family of origin is strongly associated with later violent criminality of male offspring. Further studies are needed to explore the psychosocial aspects of single-parent family environment which may promote the vulnerability to violent offending in adulthood.

Early developmental differences between DSM-III-R schizophrenics treated with clozapine and typical neuroleptics

Developmental deviance is known to be associated with schizophrenia. We tested the hypothesis that the most severe schizophrenia requiring treatment with clozapine would particularly show these effects. Therefore, associative factors from pregnancy, delivery, neonatal and socio-demographic characteristics were compared between the clozapine-treated schizophrenic cases (n = 17) and the remaining cases of schizophrenia treated with typical neuroleptics (n = 59) from an unselected, general population North Finland 1966 Birth Cohort, (n = 11,017). By the end of 1994, seventeen (22%) of a total 76 DSM-III-R schizophrenia patients, had received clozapine treatment. The mean length at birth was 52 cm in the clozapine group (in the non-clozapine group 50 cm) and correspondingly the mean one year weight 10.4 kg (9.8 kg), with the differences between the groups being statistically significant (P < 0.05). Other pregnancy, delivery, and socio-demographic characteristics were, however, similar in the clozapine-treated and the remaining cases with schizophrenia. There was no evidence that severe schizophrenia requiring treatment with clozapine was associated with impaired intrauterine or post-natal development. Indeed, during the first years of life the former group was larger in terms of weight and length than those treated with typical neuroleptics. These early developmental characteristics did not predict clinical severity of schizophrenia in adulthood.

Maturation of peripheral and brainstem auditory function in the first year following perinatal asphyxia: a longitudinal study

Maturation of peripheral hearing and auditory brainstem following perinatal asphyxia was investigated by longitudinal recording of brainstem auditory evoked potentials (BAEP) during the first year of life in affected infants. The general maturational course of the BAEP following asphyxia was similar to that in a control group of infants with normal births, although there were some abnormalities in the BAEP Response threshold elevation seen in a few asphyxiated infants improved significantly during the first 3 months. The interpeak intervals in the asphyxiated infants did not differ significantly from that of the control-group infants except in the first month, when the I-V and III-V intervals were significantly prolonged in the severe asphyxia group. In contrast, wave V amplitude and V/I ratio were always smaller when compared to that of the control-group infants. Amplitude reduction of wave V was more sustained than the prolonged I-V interval. Persistent hearing loss and brainstem auditory impairment were seen in 6.8% and 14.6% of the asphyxiated infants, respectively. These findings suggest that asphyxia does not interfere significantly with the maturation of the auditory system in most asphyxiated infants and that sustained peripheral hearing loss and brainstem impairment occur only in a small proportion of affected infants.

Free radical-induced elevation of ornithine decarboxylase activity in developing rat brain slices

OBJECTIVE

In developing brain, we have previously shown both in vivo [L.D. Longo, S. Packianathan, J.A. McQueary, R.B. Stagg, C.V. Byus and C.D. Cain, Acute hypoxia increases ornithine decarboxylase activity and polyamine concentrations in fetal rat brain, Proc. Natl. Acad. Sci. USA, Vol. 90 (1993) 692-696] and in vitro [S. Packianathan, C.D. Cain, B.H. Liwnicz and L.D. Longo, Ornithine decarboxylase activity in vitro in response to acute hypoxia: a novel use of newborn rat brain slices, Brain Res., Vol. 688 (1995) 61-71] that acute hypoxia is associated with a significant increase in ornithine decarboxylase (ODC) activity and polyamine concentrations. We tested the hypothesis that oxygen free radicals induce an increase in ODC activity similar to that of hypoxia and that both this and the hypoxia-induced response are inhibited by free radical scavengers.

MATERIALS AND METHODS

Slices of cerebrum, 300-500 microm thick, were made from P3 newborn Sprague-Dawley rat pups and equilibrated for 1 h in artificial cerebrospinal fluid continuously bubbled with 95% O2/5% CO2. Free radical-induced ODC activity response was measured beginning after a 1-h recovery period. Experiments were performed on slices treated with 5 X 10(-7) M xanthine (X) + 10 mU/ml xanthine oxidase (XO), with or without the free radical scavengers superoxide dismutase (SOD; 100 U/ml), catalase (CAT; 700 U/ml) or glutathione peroxidase (GPX; 3 U/ml). We also quantified slice malonaldehyde concentrations in response to hypoxia (21% O2/5% CO2/74% N2).

RESULTS

Under control conditions, ODC activity was stable during the 2-h post-recovery period. In response to X/XO treatment, ODC activity increased 2.3-fold at 1.5 h post-recovery. In examining ODC activity as a function of xanthine dose, we noted that ODC activity increased in response to 2.5 X 10(-7) M xanthine; however, it decreased in response to 7.5 X 10(-7) M or higher concentrations. Free radical-induced ODC activity was significantly decreased by addition of the free radical scavengers, SOD, CAT or GPX. In addition, the hypoxic-induced increases in ODC activity and malonaldehyde concentration was also eliminated by the addition of SOD with CAT.

CONCLUSIONS

(1) Oxygen free radicals, particularly hydroxyl radical (OH.), appear to trigger an induction of ODC activity in newborn rat cerebrum slices. (2) Oxygen free radicals also appear to mediate the hypoxic-induced increase in ODC activity. (3) Any consequent increase in polyamine synthesis may have profound effects on neurogenesis and neurodifferentiation in the developing brain.

Effect of hearing impairment on educational outcomes and employment up to the age of 25 years in northern Finland

The association between hearing impairment in adolescence and school performance and the outcome of education was studied among 25-year-old subjects followed since pregnancy in the Northern Finland birth cohort. The series, 395 subjects with abnormal hearing and 977 randomly selected controls, was based on a questionnaire on hearing and school achievement sent to 11780 members of the cohort alive at the age of 14 years, and on audiometric screening test requested from health centers. Hearing loss was defined as 'clinically significant' if the pure tone average (PTA; mean of the thresholds at 0.5, 1 and 2 kHz) exceeded 25 dB in the better ear; a threshold of > or = 30 dB at 4 kHz and a PTA of < or = 25 dB as '4 kHz loss'; and as 'slightly abnormal' if any of the thresholds exceeded 20 dB at any frequency and the case did not belong to the above two categories. The more severe the hearing impairment, the poorer was the child's performance at elementary school. Those with normal hearing and those with a slightly abnormal or 4 kHz loss were equally often accepted for intermediate education (88%), while those with a clinically significant loss had the lowest acceptance figures (64%). When adjusting for neurological and social confounders, excluding mental disability, the risk of not qualifying from intermediate or higher education at all was twice as high among those with a clinically significant loss as among the controls (OR 2.1, 95% CI 1.13-3.8), and was still elevated after adjustment had been made for all the relevant perinatal, neurological and social factors (OR 1.9, 95% CI 1.02-3.6). 14% of those with a clinically significant hearing loss, 9% of the subjects with a 4 kHz loss and 7% of those with normal hearing were unemployed at the age of 25 years. Hearing impairment appears to have effects on both the outcome of education and employment status.

Unwantedness of a pregnancy and schizophrenia in the child

BACKGROUND

Maternal stress during pregnancy has been suggested as a risk factor for schizophrenia. We tested the hypothesis that being the child of an unwanted pregnancy would be associated with later schizophrenia.

METHODS

Data were collected prospectively in the Northern Finland 1966 Birth Cohort of 11 017 individuals. In the sixth or seventh month of pregnancy mothers were asked whether the pregnancy was wanted, mistimed but wanted or unwanted. Schizophrenia diagnoses in the cohort members were obtained from the Finnish Hospital Discharge Register.

RESULTS

Seventy-six cases of DSM-III-R schizophrenia were identified in the whole cohort between the ages of 16 and 28 years; a cumulative incidence of 0.7%, compared with 1.5% for those born from unwanted pregnancies. The risk of later schizophrenia among unwanted children was raised compared with wanted or mistimed children, even after adjustment for confounding by sociodemographic, pregnancy and perinatal variables (OR 2.4; 95% CI 1.2-4.8).

CONCLUSIONS

The results suggest that unwantedness may operate either directly as a psychosocial stress during development making children more liable to schizophrenia, or it may be a marker for behaviours associated with risk in either the mother or the child.

Geburtsasphyxie als Ursache kindlicher Hirnschäden?

The prevalence of cerebral palsy (CP) has increased over the last 15 years in most countries. This is explained by an improved survival of very low birth weight prematures. In term infants birth asphyxia is of minor significance as a cause for CP. In only 10% of all CP cases following delivery at term, birth asphyxia must be discussed as a possible cause. In premature deliveries events during the perinatal period are of greater significance for the later development of a CP. Only severe forms of oxygen deficit, leading to tissue damage in the brain and other organs with clinical symptoms during the first days of life, are of significance for the long term prognosis. Even in the presence of severe birth asphyxia the causal relationship with a psychomotor handicap is not proven, since brain damage may have developed during pregnancy before the onset of labour and may be the cause of birth asphyxia. Brain damage and birth asphyxia may be the result of a common pathology of pregnancy.

Ornithine decarboxylase activity in vitro in response to acute hypoxia: a novel use of newborn rat brain slices

In fetal as well as newborn rats, acute hypoxic exposure results in significantly elevated brain ornithine decarboxylase (ODC) activity, polyamine concentrations, and ODC mRNA. The interpretations of these in vivo hypoxic-induced changes, however, are complicated by maternal confounding effects. To test the hypothesis that acute hypoxia will also increase ODC activity in vitro, we developed a brain slice preparation which eliminates such maternal effects. Sections of whole cerebrum, approximately 300-500 microns thick, were made from 3- to 4-day old Sprague-Dawley rat pups. The slices were equilibrated for 1 h in artificial cerebrospinal fluid (ACSF) continuously bubbled with 95% O2/5% CO2, prior to induction of hypoxia. We induced hypoxia by changing the oxygen concentration to 40%, 30%, 21%, 15%, 10%, or 0% O2, all with 5% CO2 and balance N2. In the normoxic control brain slices, low but stable basal ODC activity persisted for up to 5 h post-sacrifice. Slices in ACSF treated with bovine serum albumin (BSA), or both BSA and fetal bovine serum (FBS), however, showed stable ODC activity values 2- to 3-fold higher than slices in ACSF alone, for up to 5 h. In response to acute hypoxia (i.e., 15, 21, and 30% O2), ODC activity was elevated 1.5- to 2-fold above control values between 1 and 2 h after initiation of hypoxia. Qualitative light and electron microscopic examination of the neonatal brain slices following 2 h hypoxic exposure suggested that the great majority of cells did not show severe hypoxic damage or necrosis. It was concluded that: (1) in neonatal rat brain slices in vitro, stable ODC activity values approximating the whole brain ODC activity seen at sacrifice, can be maintained for several hours; (2) the in vivo hypoxic-induced increase in ODC activity can be approximated in vitro; (3) the neonatal rat brain slice preparation may be an alternative to other methods for studying hypoxic-induced ODC enzyme kinetics, or other brain enzymes, without maternal confounding effects; and (4) ODC activity may be an indicator of active metabolism within the newborn brain slice both in normoxia and hypoxia.

[Handicaps and the perinatal period. II. Perinatal pathology and severe deficiencies]

BACKGROUND

In the last two decades, the infant mortality rate has dramatically declined. But improved management of newborns may induce an increased prevalence of neurodevelopmental handicaps. The aim of this paper is to estimate the rate of major disabilities and their relationships to perinatal events.

POPULATION AND METHODS

Three hundred and sixteen children born in 1984 and registered by the "Commission Départementale de l'Education Spéciale" (CDES) were included in the study. Among these, 97 had either cerebral palsy, blindness, deafness, or mental retardation. These 97 children were compared to 602 school age controls using a multivariate analysis (logistic regression).

RESULTS

The rate of major disabilities among the 6-year old children is 3.4/1000. It was 5/1000 in 1972 and 4.3/1000 in 1976. This frequency is higher in the children who were preterm (odds ratio--OR = 4.8), small for gestational age (OR = 3.3) or suffered from perinatal asphyxia (OR = 32.8). These three factors accounted for 37.4% of major disabilities.

CONCLUSION

This study emphasizes the relationships between perinatal events and some major handicaps but also shows that antenatal factors may be involved in neurodevelopmental problems.

Ornithine decarboxylase activity and polyamine concentrations in fetal rat brain: response to chronic hypoxic-hypoxia and/or carbon monoxide-hypoxia

Ornithine decarboxylase activity (ODC; E.C. 4.1.1.17), is significantly elevated in fetal and newborn rat brain in response to acute hypoxia. Because relatively little is known about ODC activities and polyamine metabolism in hypoxia and also because ODC and the polyamines are essential for normal growth and development, we examined the effect of chronic maternal hypoxic-hypoxia (16-10.5% O2), carbon monoxide-hypoxia (100-200 ppm CO) and their combination, on fetal weight, fetal brain ODC activity and polyamine concentrations. Time-dated pregnant Sprague-Dawley rats were chronically exposed to hypoxia from gestational day (E-15), to gestational day 21 (E-21), in individual chambers. Pair-fed controls were given an amount equivalent to that eaten by a hypoxic dam over the previous 24 h. We measured fetal weight, as well as brain ODC activity and polyamine concentrations on both E-19 and E-21. Pair-feeding had no effect on fetal weight, ODC activity or polyamine concentrations. On both E-19 and E-21, however, fetal weights were significantly reduced with higher levels of hypoxic-hypoxia (e.g., 10.5% O2). At 100 or 200 ppm, carbon monoxide alone appeared not to affect fetal weight; however, combined with even mild hypoxia (16% O2), fetal weights were reduced almost 20%, suggesting that together, CO- and hypoxic-hypoxia exert a synergistic effect of fetal weight decrements. (1) There was no consistent pattern of ODC activity changes which correlated to the fetal weight losses or levels of hypoxia. These results suggest that ODC activity may not be a good marker for chronic, as opposed to acute hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Ornithine decarboxylase activity in fetal and newborn rat brain: responses to hypoxic and carbon monoxide hypoxia

In response to acute maternal hypoxia, ornithine decarboxylase (ODC) activity increased significantly in fetal rat brain, peaking at 4 h. This was associated with increased ODC mRNA and elevated polyamine concentrations. To correlate this response with development, we measured ODC activity in the rat from gestational day E 17 to postnatal day P 10. We also examined to what extent hypoxia induces increased ODC activity in adult rat brains and whether the response to chronic hypoxia differed from that to acute hypoxia. To test the hypothesis that this increased activity is due to hypoxic hypoxia per se, we subjected pregnant dams to inspired carbon monoxide concentrations ranging from 150 to 1000 ppm and assayed ODC activity in the fetal brain 4 h later. In the fetus, ODC activity was elevated on E 17 in the cerebrum and cerebellum. It declined gradually to about one-tenth E 17 levels by E 21 and remained low thereafter except for a postnatal elevation in the cerebellum on P 3. In response to 10.5% O2, in the 3-day-old rat, ODC activity peaked between 2 and 3 h of hypoxia, increasing 3-fold in the hippocampus and 2-fold in cerebellum. Similar increases were seen in the hypoxic adult rat brain. In inspired oxygen dose-response studies, exposure of P 3 rat pups to 13.25% O2 for 2.5 h produced a 1.5-fold increase in ODC activity; 10.5% O2 produced a 2-3-fold increase while in response to 9% O2, ODC activity remained at baseline levels. With maternal CO-hypoxia, ODC activity increased in the fetal brain at 4 h, as seen with hypoxic-hypoxia. For example, in hippocampus, ODC activity doubled at 500 ppm and tripled at 600 ppm. We conclude: (1) apparently, the ability to respond thus is not lost as the animal ages and may represent an important cellular response to acute hypoxia; (2) the increase in hypoxic-induced ODC activity is relative to the already elevated activity seen from E 17 to E 20; a vast reserve for the induction of fetal ODC activity probably exists and may indicate the importance of this enzyme during this time frame for differentiation and growth promotion; and (3) the CO-hypoxia studies suggest that some aspects of the cellular responses to CO- and hypoxic-hypoxia are similar.

Association of perinatal events, epilepsy, and central nervous system trauma with juvenile delinquency

The association of perinatal events, childhood epilepsy, and central nervous system trauma with juvenile delinquency was studied prospectively in a geographically defined population of 5966 males in northern Finland. Those who had obtained a criminal record up to the age of 22 years, totalling 355, or 6.0%, were defined as delinquents. The incidence of delinquency was not increased in males with a birth weight less than 2500 g or greater than 4000 g, preterm births < 37 weeks' gestation, or those with perinatal brain damage or having epileptic seizures before 14 years of age. The incidence was increased by 6.8% in the group of males with birth weights less than 3500 g, but not significantly increased after standardisation for a number of social and demographic background variables. The incidence was increased by 10.3% among the males who had had a central nervous system trauma by the age of 14 years, however, and this factor remained significant when social and demographic factors were standardised by regression analysis, with an odds ratio of 1.9 for all males with a criminal record and an odds ratio of 3.15 for those who had committed a violent crime. Previous central nervous system trauma may be a cause of delinquency, or another possibility is that the type of behaviour pursued by males who are likely to commit a violent crime will expose them more often to accidents which can result in central nervous system trauma.

Birth asphyxia: a crucial issue in the prevention of developmental disabilities

Birth asphyxia is one of the most common causes of neonatal and infant mortality and morbidity in developing countries. In this paper the prevalence of the problem is described, and some suggestions for its prevention, identification and management are given.

Chronic hypoxia in neuronal cell culture: metabolic consequences

Cerebral cortical cell cultures obtained from fetal mice were subjected to 5% O2 for 24 h at a developmental stage equivalent to that of the human neonate. Immediately after the hypoxic insult (HI), medium lactate was elevated and pH, partial pressure of oxygen, and bicarbonate concentration were depressed compared to controls. At this time, the cultures evidenced a modest reduction in high-affinity GABA uptake but minimal morphologic or other biochemical evidence of cellular dysfunction. Within 24 h of restitution of normoxia, there was prominent disruption of neuronal integrity as well as significant reductions in benzodiazepine (BDZ) receptor binding, clonazepam-displaceable (CLO) BDZ binding, high-affinity uptake of GABA and beta-alanine, choline acetyltransferase (ChAT) activity, and total protein. Except for the neuronal marker CLO, GABA uptake was depressed more than other parameters for the subsequent 72 h. In contrast, the non-neuronal marker, Ro5-4864-displaceable BDZ binding, was always increased. Both morphologic and biochemical changes occurred independent of correction of pH, bicarbonate, and lactate. These data suggest that chronically hypoxic nervous tissue in vitro exhibits considerable delay in the evolution of maximal abnormality but that a population of GABAergic cells may be relatively more vulnerable. Although glial cell stimulation may contribute to neuronal survival, it also is possible that, because of the temporal association with cellular dysfunction, restitution of normoxia may contribute to nervous tissue injury.

The longitudinal study of the northern Finland birth cohort of 1966

The Northern Finland birth cohort comprises 12,058 live births in 1966-96.3% of all births in the region. The investigation was started during pregnancy and the last follow-up of the total series was at the age of 14 years, when the coverage was still large. Smaller samples of the children and data for the study population from national registers were also examined for the older age groups. The health and development of the children was studied, with special emphasis placed on obtaining reliable incidence figures for neurological handicaps and their correlation with perinatal events. In particular, the correlation between low birthweight and handicapping conditions was documented thoroughly. The indicators predictive of low birthweight among the biological characteristics of the mother and the social conditions of the mother and family, included maternal smoking during pregnancy. The latter was associated not only with adverse perinatal outcome but also with reduction in educational achievement and height among survivors.