Niels Græm

Reduced cell number in the neocortical part of the human fetal brain in Down syndrome.

Mental retardation is seen in all individuals with Down syndrome (DS) and different brain abnormalities are reported. The aim of this study was to investigate if mental retardation at least in part is a result of a lower cell number in the neocortical part of the human fetal forebrain. We therefore compared brains of DS fetuses aged 19 weeks of gestation with normal control brains. The cell numbers were estimated using the optical fractionator method. The total cell number in the neocortical part of four DS human fetal forebrain was found to be substantially smaller in DS compared to the normal fetus. The average total cell number of 6.85 billion was equal to a reduction by 34% compared to the 10.4 billion cells in a normal fetal brain of that age. This study indicates that the mental retardation found in DS is based on a structural deficit in the human fetal brain already present in the second trimester.

Total number of cells in the human newborn telencephalic wall.

The total cell numbers were estimated in the neocortical part of the human telencephalon in 10 normal brains of newborn babies within four major developmental zones: the cortical plate/marginal zone, the subplate, the intermediate zone and the ventricular/subventricular zone. Furthermore, the total number of neuron and glial cells was estimated in the cortical plate. The gestational ages ranged from 38 + 0-42 + 5 weeks + days of gestation. The mean total cell number was 32.6 x 10(9) (coefficient of error = 0.04) and the total number of neurons in the cortical plate 19.8 x 10(9) (coefficient of error = 0.06). This indicates that the total number of neocortical neurons equals the total number in the adults, which, however, is not the case for the glial cells.

Radiography in post-mortem examinations of fetuses and neonates

During the last decade there has been an increasing interest in radiological investigation of stillborns and neonates as a supplement to autopsy. A consecutive series of 137 fetuses and neonates is presented. Prior to autopsy plain X‐ray films were taken, and in 50% arteriography was performed by injecting contrast medium into an umbilical or femoral artery. On the plain films only 41% were normal. The major part of the abnormal radiographs exhibited minor abnormalities such as transverse lines or “stress‐lines” of the bones, cercival ribs or an abnormal numbers of ribs. Major abnormalities were seen in 9%. Most of these were abnormalities of the spine. The arteriographs were very detailed and were abnormal in 29% of the cases. The technique was not suitable for demonstration of heart malformations. It is concluded that plain film X‐ray of soft tissues and bones is recommendable as a routine procedure, whereas arteriography should be limited to cases suspected of vascular malformations or if an autopsy cannot be performed.

Spatiotemporal Distribution of PAX6 and MEIS2 Expression and Total Cell Numbers in the Ganglionic Eminence in the Early Developing Human Forebrain

The development of the human neocortex is a complex and highly regulated process involving a time-related expression of many transcription factors including the homeobox genes Pax6 and Meis2. During early development, Pax6 is expressed in nuclei of radial glia cells in the neocortical proliferative zones and controls the differentiation and neurogenetic fate of these cells in the dorsal telencephalon in rodents. Animal studies on the Meis2 gene have revealed expression in the developing telencephalon and Meis2 is known to regulate the expression of Pax6 in the eye and pancreas. Because of this functional relation between Pax6 and Meis2, we studied the spatial and temporal expression of PAX6, and MEIS2 using a developmental series of human fetal brains at 7–19 postconceptional weeks with emphasis on the forebrain to investigate whether the two genes are expressed in the same regions and zones in the same time window. We demonstrate by in situ hybridization and immunohistochemistry that the two homeobox genes are expressed during early fetal brain development in humans. PAX6 mRNA and protein were located in the proliferative zones of the neocortex and in single cells in the cortical preplate at 7 fetal weeks and in the developing cortical plate from 8 or 9 to 19 fetal weeks. The expression of PAX6 expanded into the ganglionic eminence just prior to the stage at which a stereological estimation showed an exponential rise in total cell number in this area. The MEIS2 gene was also present in the proliferative zones of the human fetal neocortex and a higher expression of MEIS2 than PAX6 was observed in these areas at 9 fetal weeks. Further, MEIS2 was expressed at a very high level in the developing ganglionic eminence and at a more moderate level in the cortical plate.

Expression of bcl-2 in fetal thymus, thymomas and thymic carcinomas : Association with p53 expression and review of the literature

Bcl‐2 is a proto‐oncogene inhibiting apoptosis, and p53 is a tumor supressor gene which induces apoptosis. Both seem to take part in tumorigenesis. An inverse relationship between the two genes has been reported in some neoplasms, although the exact mechanism is not fully understood. We have analyzed the expression of bcl‐2 and p53 in 18 fetal thymuses and 18 clinically benign and malignant thymomas: bcl‐2 was expressed by most medullary lymphocytes and epithelial cells of the normal thymus; p53 was not expressed at all. Bcl‐2 and p53 were co‐expressed in the majority of the thymomas and the staining reaction was stronger in the clinically malignant ones. It is concluded that although co‐expression of bcl‐2 and p53 is of doubtful prognostic relevance, the staining pattern of bcl‐2 supports the histogenetic classification system of Müller‐Hermelink.

Accuracy of frozen section diagnosis: a retrospective analysis of 4785 cases

Winther C, Græm N. Accuracy of frozen section diagnosis: a retrospective analysis of 4785 cases. APMIS 2011; 119: 259–62.

Recurrent fetal polycystic kidneys associated with glutaric aciduria type II

A woman had two pregnancies terminated in the 20th and 21st weeks of gestation after ultrasonographic detection of enlarged hyperechoic kidneys in both fetuses. The combination of polycystic kidneys and steatotic liver found at autopsy suggested glutaric aciduria type II (GA II), which was confirmed by biochemical investigation. GA II or multiple acyl‐CoA dehydrogenase deficiency is an autosomal recessively inherited defect of mitochondrial energy metabolism, which usually results in neonatal death. When pregnancy is terminated because of enlarged hyperechoic kidneys in the fetus, autopsy is crucial for establishing the correct diagnosis. The combination of polycystic kidneys and steatotic liver should bring GA II to mind, and prompt appropriate biochemical investigations so that genetic counselling and first trimester diagnosis can be offered in future pregnancies.

Correlation between prenatal diagnosis by ultrasound and fetal autopsy findings in second‐trimester abortions

Abstract  We evaluated the correlation between prenatal diagnosis by ultrasound and autopsy findings, based on 52 second‐trimester pregnancies terminated due to fetal malformations or chromosome aberrations diagnosed at a gestational age of 12–25 weeks. In 24 pregnancies, there was full agreement between ultrasound and autopsy. In 23 fetuses, the main diagnosis was confirmed and additional or more specific findings were observed on autopsy. In five fetuses, there were considerable differences. Discrepancies between ultrasound and autopsy findings were mainly anomalies undetectable by ultrasound and thus expected; however, about one‐third of the discrepancies were not expected, representing findings that were ‘missed’ at ultrasound. The main ultrasound diagnoses were confirmed in the majority of the pregnancies, but the additional information obtained at autopsy in more than half of the fetuses clearly shows the value and benefit of postmortem fetal examination following termination of a pregnancy.

Histo-blood group antigens in human fetal thymus and in thymomas

The glycosylation of epithelial cell surface antigens follows cellular differentiation, and changes in the pattern of expression are seen in various premalignant and malignant epithelial lesions. The distribution of type‐2 chain ABH‐carbohydrate structures (N‐acetyl‐lactosamine, H‐type 2 chain, Le‐y, Le‐x and sialyl‐Le‐x) of the ABO‐histo‐blood group system was investigated in 19 normal fetal thymuses (gestational age 16 to 39 weeks) and in 19 thymomas in order to study possible tumor‐associated changes in the glycosylation pattern. The material was investigated by immunochemical stainings of formalin‐fixed paraffin‐imbedded tissue using monoclonal antibodies with defined specificity. In fetal thymus the epithelial cells of the medulla and the Hassals bodies strongly expressed elongated carbohydrate structures (Le‐y, Le‐x and sialyl‐Le‐x). In a few cases the cortical epithelial cells weakly expressed Le‐x and sialyl‐Le‐x. Compared with fetal thymus 16 of the thymomas showed a total loss, or a very much reduced expression of elongated carbohydrate structures. Three thymomas, which histologically had been reclassified according to Kirchner & Müller‐Hermelink (14) as high grade thymic carcinomas, revealed strong expression of Le‐y, moderate expression of Le‐x and weak expression of sialyl‐Le‐x. This is of interest as in other tumors Le‐y is correlated with increased cell motility and with poor prognosis.

Blood group related carbohydrate antigens in human fetal pancreas

Many tumor‐associated carbohydrate antigens are related to the blood group systems. Since several of these antigens are developmentally regulated, a systematic knowledge of the expression of blood group related carbohydrate antigens during organogenesis is important. By immunohistochemical methods we investigated the expression of carbohydrate structures related to the ABH, Lewis, T and Tn blood group systems in 28 fetal pancreas, from 13th‐40th gestational week using a comprehensive set of well‐defined monoclonal antibodies, reacting with type 1,2,3, and 4 chain carbohydrate structures. The following antigens were found in fetal pancreas: Type 1 chain: Lea, Leb, monosialylated Lea and disialylated Lea, type 2 chain: N‐acetyllactosamine (the immediate precursor to blood group H antigen), branched N‐acetyllactosamine, H‐antigen, Lex and Ley; type 3 chain: H‐antigen. The T‐antigen was well expressed, whereas this was not the case with the Tn‐antigen. As expected the A‐antigen was found in 10 of 24 cases. The A‐related antigens: ALeb, ALed and ALey were only found in a few of these ten specimens whereas type 3 chain A‐repetitive was found in all of them. Since msLea, Lex, Ley and T‐antigen have been described as tumor‐associated antigens, we conclude that several carbohydrate tumorrelated antigens are expressed in fetal pancreas.