ABSTRACT Congenital diaphragmatic hernia (CDH) and lung hypoplasia were induced in high frequency and dose-dependently in the offspring from dams, treated orally with 2, 4-dichlorophenyl-p-nitrophenyl ether (nitrofen) during pregnancy in CD-1 mice and CD rats. Both in mice and rats, CDH found in the fetal and neonatal periods was a posterolateral type of diaphragmatic hernia (DH) showing a distinct side-preponderance: the left-side preponderance in mice and right-side preponderance in rats. CDH in the offspring, surviving after weaning, was mostly of retrosternal type in mice and of pericardial type in rats. CDH induced experimentally in the present study can be regarded as an excellent animal model for human CDH in terms of both anatomical features and the time of ap- pearance of different types of CDH as well as clinical symptoms. Lung hypoplasia was observed in the offspring with and without CDH; though its severity was greater in those with CDH. The offspring with severe lung hy- poplasia died of respiratory insufficiency during the neonatal period, regardless of the presence or absence of CDH. These findings suggest that lung hypoplasia is not a consequence of CDH, but that a common pathogenetic process in the early embryonic stage might involve both lung hypoplasia and CDH.
ABSTRACT The effects of maternal hyperphenylalaninemia induced by phenylala- nine and p-chlorophenylalanine loading diets on brain growth and myelination were studied in mice. The wet weights, protein contents and activities of 2’, 3’-cyclic nucleotide 3’-phosphodiesterase (CNP) of the cerebrum, brain stem and cerebellum were estimated on 7, 14, 21, 28 and 56 days after the birth. Protein and lipid contents in the myelin fraction of the whole brain were also examined on days 28 and 56. In the experimental groups, the activities of CNP, a marker en- zyme of myelin, were lower than those in the control in each part of the brain. The protein contents in the light myelin subfraction, which is regarded as a mature type of myelin, were also decreased in the experimental group after 28 days of age, while those in the heavy myelin subfraction, which is regarded as an immature type of myelin, showed no significant reduction even after 28 days of age. These results suggest that maternal hyperphenylalaninemia has a potential effect on post- natal myelination of the brain, and also that impaired myelination may play some role in the pathogenesis of mental retardation of maternal phenylketonuria. The proportions of unsaturated to saturated fatty acids in phosphatidylethanolamine and sphingomyelin were decreased significantly on day 56 in the heavy myelin subfraction in compariscin to the controls. These changes may have some correla- tion with interference in the formation of matured myelin.
ABSTRACT This paper of Golgi studies describes abnormal dendritic structure and development assessed by camera lucida representation, quantitation of den- dritic spines, and dendritic branch measurement in metabolic and chromosomal diseases with mental reta.rdation, reviewing the literatures of Golgi study. Neuronal lipid storage diseases with progressive mental and motor deterioration show characteristic meganeurites between the soma and origin of the axon, and all dendrites have fewer number of branches, shorter total basal dendritic length and marked reduction of spines. Phenylketonuria and Lesch-Nyhan syndrome also present decreased number of spines. On the other hand, children and adults with Down’s syndrome show poor dendritic spine density and l dendritic branchings as well as structural irregularity of spines. This poor‘ development of dendrites suggesting postnatal poor synaptogenesis may be related to mental retardation in children. These postnatal den- dritic abnormalities may be based on genetic factors such as diminished number of cortical granular cells and extrinsic factors which include poor perception of external stimuli as noted in sensory deprivation. Thus, dendritic spine abnormalities may be correlated with mental retardation. However, we need better staining method and more sytemic study.
ABSTRACT Characteristics of synaptic development are as follows: 1) an increase- decrease in the number of synapses consisting of an over-production followed by elimination, the end product being the maturing form; 2) with maturation, there is a transformation from the axo-dendritic shaft synapses to the axo-dendritic spine ones. In early development, synaptogenesis probably proceeds simultaneously with myelination. A suggestion that the critical period giving definitive impairments in the organization of synapses exists may be raised. Quantitative analyses of the mitochondria1 number in the presynapse, determined using conventional osmium tetroxide staining and the number of synaptic junction determined using the EPTA preferential procedure reveal the synaptic changes, both in normal development or in response to nutritional and pharmacological factors.
ABSTRACT Investigations by using animal models offer a useful tool to study the pathogenesis and cure of several incurable human diseases. The laboratory animal science in this field was established about 20 years ago in Japan. This paper describes the outline of its history and the characteristics of each animal model which has been studied extensively and will also be studied in the future in Japan. Some results on dystrophic c:hicken and gracile axonal dystrophic (gad) mouse which were recently obtained in our laboratory are discussed.
ABSTRACT Pathogene tically, mental retardation (MR) may be classified into three basic forms, including MR with grossly evident developmental abnormalities of the CNS, MR with encephaloclastic, sclerotic and atrophic change of central nervous tissue, and MR without evident alterations of the CNS at the routine microscopic level [“poor morphology MR (PMMR)”] . The complicated polyetiologic situation of MR will be summarized in a multigraph in order to provide a synopsis of the manifold interrelations ,and of the general factors involved in the origin and patho- genesis of MR. PMMR is said to comprise about 40% of the observations of MR. However, with special techniques, such as selected silver impregnations, immuno- cytochemistry, electron microscopy, autoradiography, and others, morphologic correlates may also be demonstrated in PMMR at the fine structural level. Of great importance in this respect are not only factors interfering with intrauterine development, but also mechanisms acting upon postnatal differentiation in the most critical period of brain plasticity. This fact should deserve more attention in future morphologic research into the fine structural and molecular correlates of MR. The same is true for CNS myelination which has only infrequently been considered in former investigations into MR. Further, not only the quality and quantity of changes in the CNS should be regarded, but also their topographic distribution in MR. The reticular formation and the hippocampus (limbic system) will be emphasized as sites of major importance in thu respect. Future implications for research into morphologic correlates of PMMR will be discussed. Special emphasis will be put on the importance to take more advance of the results of basic neurobiologic research into the molecular bases of learning and behavior as a guideline for future research into PMMR.
ABSTRACT In order to examine the direct effects of cytosine arabinoside (Ara- C) on cerebellar development, Slc: ICR mice were treated intracisternally with a single dose of 160 pg ha-C on day 0, 1, 2, 4, 5, 7 or 10 after birth. The mice in each group were killed at 30 days of age. Cerebellar weight was heavily reduced, but body and total brain weights were only slightly reduced in all Ara-C-treated groups. In mice treated on day 0, 1 or 2, derangement of the layered structure of the vermis was evident in the anterior folia. In the immunohistochemical examinations with GFAP and S-100 protein, Bergmann glial fibers ran tortuously and not perpendicular to the pia mater in the disarranged area. Bergmann glial cell bodies were scattered in the cerebellar cortex and not always adjacent to Purkinje cells. In the group treated on day 4 or later, the layered structure of the vermis was well preserved.