ABSTRACT Congenital hydrocephalus has a broad spectrum of etiology and has not been elucidated in terms of pathogenesis or mechanism of hydrocephalus. Recent advance of molecular genetics disclosed the genetic defects of X-linked hydrocephalus (HSAS), MASA syndrome and X-linked spastic paraplegia (SPG I), characterized by mutations in LICAM, a gene coding for a neural cell adhension molecule. Meanwhile, genetic heterogeneity in X-linked hydrocephalus has been pointed out; linkage to markers within Xq27.3. We reviewed inherited hydrocephalus and chromosomal aberrations with hydrocephalus because fibroblasts from patients with these disorders may be useful for a molecular genetic approach to inherited hydrocephalus. Animal models of congenital hydrocephalus are also very important for a comparative mapping analysis between mice and human. We have tried to clone a candidate gene of hydrocephalus using fibroblasts which show a de nove chromosomal aberration [t(4; 16)(q35;q22. I)], because the synteny conservation locus for mouse hydrocephalus-3 (hy-3) gene is suggested to be located in the long arm of human chromosome 16. A rearranged band of 1.2 Mb was detected by Pulse-Field Gel Electrophoresis (PFGE) with Not I digestion using the calretinin probe. It may exist within 1.2 Mb distal apart from calretinin gene. Further analysis is carried out in order to clone this candidate gene of congenital hydrocephalus.
ABSTRACT Various types of errors are shown in a mentally retarded boy (CA 12:10, Tanaka-Binet IQ 45-50) engaging in a standardized arithmetic achievement test for first- grade pupils. The following issues on behavioral characteristics of the mentally retarded with arithmetic tasks are discussed from a special educational point of view. 1. Production of correct solutions depends heavily on self-regulation, motivation and metacognition levels of the retarded with arithmetic tasks. Therefore, maintaing appropriate levels of these processes is a fundamental principle in encouraging the mentally retarded to do their best. 2. How the retarded deal with a task on figures depends on how the figures appear to them. It is a perceptual problem rather than an arithmetic one. 3. While the retarded can do well on a task by manipulating the objects in question in his daily life, they cannot solve the same task in an achievement test situation. They attempt to solve a task using a familiar strategy and are difficult to change the one used. They adopt a known strategy with a clue of particular word, phrase or part of story to deal with the tasks. 4. Realization of how to use the counting principles develops step by step, but under- standing process of every principle on cardinal progression is one thing and that on multiple progression is another.
ABSTRACT PddPdn mouse exhibits preaxial polydactyly and arhinencephaly, including various brain abnormalities such as the absence of corpus callosum and hydrocephaly. We have investigated the mechanism of the manifestation of polydactyly. The abolishment of the deep preaxial mesodermal programmed cell death, foyer primaire prkzxial (fpp), has been considered to be the starting point of the manifestation of preaxial polydactyly. With this hypothesis, we electrocauterized the fpp region of PddPdn embryos, because Pdd Pdn lacks fpp. After surgery, PddPdn embryos were developed using whole embryo culture system or ex0 urero method. They exhibited 5 digits in their limbs which received surgery in fpp region. Meanwhile, much more apoptotic degenerations were observed in the brains of Pdd Pdn newborns and embryos than normals. Anti-single-stranded DNA antibody was used to detect the localization of apoptotic cell death in the brains of PddPdn mice. TRPM-2 gene has been considered to be an indicator of apoptosis. The brains of PddPdn newborns and embryos showed higher TRPM-2 gene expression in Northern blot analysis. From these results, we speculated that abnormal apoptosis in the periventricular zone induced the expansion of the ventricle followed by hydrocephaly.
ABSTRACT Clinical methods of neonatal neuro-behavioral evaluation are outlined, and the conceptual basis and the procedures of Brazelton’s Neonatal Behavioral Assessment Scale (NBAS) which is most widely used is described in detail. The studies which have been conducted to date using the NBAS are reviewed, and future directions in the assessment of neonatal behavior are explored. Infants showed following behavioral characteristics: Healthy Japanese infants show higher habituation and orientation scores with lower motor activity score than American Caucasian counterparts. Japanese infants with intra- uterine growth retardation (IUGR) show mild deviation of Apgar score, and maternal toxemia has an effect on the neonatal behavior as well as neurological signs. In Japanese infants, the mental-motor development during infancy is significantly correlated with the neonatal behavior and family environment. Studies of normal and high-risk infants revealed that both perinatal complications and cultural background affect the neonatal behavior.
ABSTRACT Our previous study suggested that the teratogenic effect of methamphet- amine (MAMP) may be influenced by the housing conditions under which drug-treated pregnant animals were kept (Yamamoto et al., 1992). In the present study, pregnant mice were housed individually and their teratological data were compared with those obtained in the previous study where pregnant females were housed in aggregated groups. Pregnant mice were individually housed in a plastic cage and they received i.p. 1 I, 13, 15, 17, 19, or 21 mg/kg MAMP hydrochloride on day 8 of pregnancy (plug day = day 0). All the pregnant females treated with MAMP survived to term; this was in contrast to the high mortality rate of the animals which were treated with MAMP and kept in groups. No significant difference in the number of implantations and the resorption rate was noted between the control and treated groups. Malformed fetuses (externally, skeletally or vis- cerally) were encountered in the MAMP-treated groups at prevalence rates of 0.6-3.2%, but the rates were not significantly different from the control value. The incidence of malformations was significantly lower in the groups kept in solitary conditions than in aggregated groups examined previously. The present study showed that crowding of pregnant females can potentiate the teratogenic effects of MAMP in mice. Some maternal physiological alterations caused by crowded environment such as stress-induced glucocorticoid secretion and maternal hyperthermia may be responsible for the potentiated teratogenicity of MAMP in crowded housing conditions.
ABSTRACT Aurintricarboxylic acid (ATCA) was injected into the ventricle of mouse embryo on day 14 of gestation using exo utero method. Severe hydrocephalus and destruction of aqueductus cerebri were induced in the ATCA-treated fetuses. Thinning of the cerebral cortex and widespread cell deaths in the periventricular wall of cerebrum, thalamus and hypothalamus were observed in the histological sections. The cell death was investigated immunohistochemically using an antibody against single-stranded DNA. This antibody did not react to the dying cells, so it was suggested that the cell deaths were not apoptosis. TRPM-2 gene expression was investigated in the hydrocephalic and normal brains on day 18 of gestation using dot-blot hybridization analysis. However, the gene expression in the hydrocephalic brain did not increase. In the present experiment, intraventricular injection of ATCA on day 14 of gestation induced severe hydrocephalus in mice, and cell deaths in the periventricular wall were considered to be necrosis.
ABSTRACT Catecholamine and amino acid contents in the brain of the macular mutant mouse, a model mouse of Menkes kinky hair desease, were studied at days 4, 7, 10 and 13 postnatally. The contents of norepinephrine and epinephrine in the macular mutant mouse brain were significantly lower than those of controls at all ages. In contrast, the content of dopamine in the mutant mouse brain was significantly higher than that in the controls at days 4 and 7, and then it decreased rapidly to become less than that of age- matched controls at days 10 and 13. Body weight gain of mutant mice was remarkably stunted, and weight loss was observed at day 7 of age. Body weight at day 13 postnatum was 56.1% that of the control. To examine the possible effects of malnutrition on the catecholamine metabolism in the mutant mouse brain, the contents of various amino acids in the brain and serum were measured. In the mutant mouse serum, tyrosine and phenylalanine, which play key roles in catecholamine metabolism, were significantly reduced compared to control, whereas only tyrosine showed a significant decrease in the brain. These results indicate that the rapid decrease in the catecholamine content in the macular mutant mouse brain is possibly influenced by the decrease in serum tyrosine subsequent to progressive malnutrition.