Haemorrhage into cerebral parenchymal tissue supero-lateral to the angles of the lateral ventricles is a major cause of death and disability in preterm infants. It is frequently associated with germinal layer and intraventricular haemorrhage but the mechanism by which parenchymal haemorrhage occurs is uncertain. Recent studies have suggested that it is due to bleeding into tissue previously damaged by ischaemia following cerebral hypoperfusion. We have studied 68 preterm infant brains, of which four contained early intraparenchymal haemorrhage supero-lateral to the angles of the lateral ventricles which were associated with large germinal layer and intraventricular haemorrhages. The anatomical distribution and histological features of these haemorrhages suggested that they resulted from venous infarction and that the venous drainage of the periventricular tissues had been obstructed by the germinal layer haemorrhages. In these four infants, bleeding into parenchymal tissues could be regarded as a complication of germinal layer and intraventricular haemorrhage rather than of cerebral hypoperfusion.

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SUMMARY Abnormalities detected by a mechanical sector scanner were compared ‘blind’ with autopsy findings in the brains of 56 infants born at less than 33 weeks gestation. Intraventricular haemorrhage was found in 53 of 112 hemispheres and had been accurately diagnosed by ultrasound (sensitivity 91 per cent; specificity 81 per cent). Isolated germinal layer haemorrhage was less successfully identified (sensitivity 61 per cent; specificity 78 per cent); false‐positive diagnoses were partly due to difficulty in distinguishing haemorrhage from the normal choroid plexus in extremely preterm infants. Haemorrhagic parenchymal lesions were correctly identified in nine infants (sensitivity 82 per cent; specificity 97 per cent). Only 11 of 39 hemispheres with histological evidence of hypoxic‐ischaemic injury, without marked bleeding, were correctly identified by ultrasound (sensitivity 28 per cent), mainly because of failure to detect small areas of periventricular leucomalacia and diffuse gliosis. 10 hemispheres with periventricular echodensities thought to represent leucomalacia showed no histological evidence of hypoxic‐ischaemic injury (specificity 86 per cent). Ventricular dilatation in seven infants was always associated with evidence of hypoxic‐ischaemic injury at autopsy. RÉSUMÉ Précision du diagnostic échographique des lésions vérifiées post‐mortem dans le cerveau des grands prématures Les anomalies détectées à une échographie mécanique sectorielle ont été comparées ‘à l'aveugle’ avec des données d'autopsie pour les cerveaux de 56 nourrissons, nés à moins de 33 semaines de gestation. Une hémorragie intraventriculaire a été trouvée à l'autopsie dans 53 des 112 hémisphéres et a été diagnostiquée avec précision par I'échographie (sensibilité 91 pour cent; spécificité 81 pour cent). L'hémorragie isolée de la couche germinative a été identifiée avec moins de succés (sensibilité 61 pour cent; spécificité 78 pour cent). Les diagnostics faux‐positifs ont été en partie liés à une difficulté de distinguer I'hémorragie du plexus choroide normal chez les grands prématurés. Les lésions d'hémorragies parenchymateuses ont été correctement identifiées chez neuf nourrissons (sensibilité 82 pour cent; spécificité 97 pour cent). La réalité histologique de lésions hypoxiques‐ischémiques sans saignement marqué n'a été correctement identifiée par échographie que dans 11 des 39 hémisphéres (sensibilité 28 pour cent), principalement en raison de l'échec de détection de zones limitées de leucomalacie périventriculaire et de gliose diffuse. Pour 10 hémisphéres oú des échodensités périventriculaires avaient été interprêtées comme leucomalacies, il n'y avait pas d'évidence histologique de lésions hypoxiques‐ischémiques (spécificité 86 pour cent). La dilatation ventriculaire chez sept nourrissons était toujours associée à des lésions hypoxiques‐ischémiques évidentes à I'autopsie. ZUSAMMENFASSUNG Genauigkeit der Ultraschalldiagnose von pathologisch verifzierten Hirnläsionen sehr junger Frühgeborener Bei 56 Neugeborenen mit einem Gestationsalt...

Amniocentesis and withdrawal of amniotic fluid was performed on pregnant monkeys (Macaca fascicularis) at two stages in development, either between 47 and 64, o r between 85 and 95 days gestation. After birth the lungs of each infant monkey were studied using precise morphometric techniques, and compared with those in a control group of animals. The lungs after amniocentesis had alveoli of normal maturity but reduced in number and increased in size, features which both reduce the relative area for gas exchange. There was also a reduction in the number of respiratory airways. These changes occurred regardless of the time of amniocentesis, the amount of fluid removed and even if the membranes were simply punctured with no fluid removal. There is some evidence t o suggest that similar sublethal effects may be present in human infants after maternal amniocentesis.Amniocentesis and withdrawal of amniotic fluid in the midtrimester of pregnancy are now used increasingly to enable antenatal diagnosis of chromosomal and biochemical disorders in the fetus. In later pregnancy (20-35 weeks) amniocentesis is used in the management of rhesus disease, and there is often repeated sampling of fluid. The Report to the Medical Research Council by their Working (1978) showed hitherto unsuspected hazards of midtrimester amniocentesis, namely an increased incidence of unexplained respiratory difficulties in the offspring at delivery (1 '3% in the matched subjects versus 0.4% in controls) and also an increased incidence of major orthopaedic postural deformities in the offspring (1% in subjects versus 0 2% in controls). Both these findings may be related to amniotic fluid volume changes occasioned by the removal of fluid or by its continued leakage. Party on AmniocentesisThe concurrence of oligohydramnios and Correspondence: A. Hislop, Department of Obstetrics and Gynaecology, 88-96 Chenies Mews, London IVC 1 E 6HX.

In the cerebral lateral ventricle of the human fetus, the embryonic ventricular and subventricular zones (VZ and SVZ) persist into the latter half of gestation, particularly in the lateral wall. The SVZ is usually referred to as the germinal layer at this stage. The VZ is gradually replaced by ependyma, a single epithelial layer composed of tanycytes and ciliated columnar cells. In the prematurely born infant, the germinal layer is frequently the site of haemorrhage, the incidence of which diminishes with increasing maturity. There are many contributory pathogenetic factors but the structure of the germinal layer itself is considered important. It contains numerous, thin walled vessels in a cellular matrix which demonstrates little fibrillary background. Immunohistochemical evidence of glial differentiation in the germinal layer was sought in 21 preterm brains, using antibody to glial fibrillary acidic protein (GFAP). Early immunoreactivity was due to GFAP positive tanycyte fibres. Subsequently, associated with astrocyte differentiation, there was progressive development of a glial fibre network. It is suggested that the increase in glial fibres may be a significant factor in capillary stabilization, and in the inverse relationship between gestation of the infant and the risk of intracerebral haemorrhage. The possible structural significance of the tanycyte is also highlighted.