ABSTRACT Proteoglycan is a family of glycoproteins which carry covalently-linked glycosaminoglycan chains, such as chondroitin sulfate and heparan sulfate. Proteoglycans are believed to play important roles in morphogenesis and maintenance of various tissues including the central nervous system (CNS) through interactions with cell adhesion molecules and growth factors. In the CNS, a significant amount of evidence has been accumulated to show that proteoglycans function as modulators in various cellular events not only in the development, but also in the pathogenesis of neuronal diseases and lesions. When the CNS is injured, several chondroitin sulfate proteoglycans (CSPG) are up-regulated in glial scars formed around the lesion site. The glial scar also contains some molecules inhibitory to axonal growth, such as myelin-associated glycoprotein, Nogo, and Semaphorin. In vitro studies revealed that CSPG largely exert a repulsive effect on axonal regeneration, and a signal from CSPG modulates the actin cytoskeleton of outgrowing neurites through the Rho/ROCK pathway. These findings suggest that CSPG are responsible for unsuccessful axonal regeneration in glial scars. Various attempts to overcome the inhibitory effect of CSPG have been pursued in vivo. Digestion of chondroitin sulfate chains by chondroitinase ABC, suppression of CSPG core protein synthesis by decorin, suppression of glycosaminoglycan chain synthesis by a DNA enzyme, and inhibition of the Rho/ROCK pathway with specific inhibitors were all successful for increasing axonal regeneration. For a clinical application, the most effective combination of these treatments needs to be examined in the future.
ABSTRACT This study estimated total number of Purkinje cells in the cerebellum of an ataxic mutant mouse, dilute-lethal (DL), with reference to severe ataxic symptoms of this mutant. On postnatal day (PD) 21, the cerebellar weight is significantly lower in DL than in non-ataxic littermates (control mice). Total number of Purkinje cells is also significantly lower in DL than in the controls; approximately 25% less in DL than in the controls. Furthermore, we performed in situ nick end labeling (TUNEL) -staining in the cerebellum of DL during prenatal and postnatal periods in order to examine the cause of the reduced Purkinje cell number. For analyzes of the mutant fetuses, it is necessary to identify the homozygous mutant. We succeeded in identifying the homozygous DL fetuses from the control fetuses (wild-type or heterozygous fetuses) by the hair color of the grafted skin pieces on nude mice. The histological features of the cerebellar primordium did not differ between the DL and controls on embryonic and postnatal ages examined. In DL, a significantly greater number of TUNEL-positive Purkinje cells was detected on embryonic day (ED) 12, but not throughout ED 14 to PD 21. The results suggest that the Purkinje cell loss in the DL cerebellum is attributed to increased apoptotic cell death of the progenitors. This may be involved in the development of severe ataxic symptoms of DL.
ABSTRACT Non-invasive prenatal diagnostic methods posing no danger to the embryo have been desired for many years in the field of prenatal medicine. We are in the process of improving the lectin method that we developed for recovering fetus-derived nucleated red blood cells (NRBC) in the maternal peripheral blood. We previously used Ficoll density-gradient centrifugation for preliminary concentration in the lectin method. In the present study, we developed a molecular filter method, compared it with the Ficoll method, and tested its applicability to prenatal diagnosis. We tested the usefulness of a high molecular filter method for preliminary concentration. First, in a basic study, we prepared three kinds of non-woven cloth (NWC1-3) and a multi-porous filter (MP) to determine the optimal filter. Next, we compared the recovery rates of the Ficoll and filter methods as preliminary concentration methods in 34 normal pregnant women. Then, to examine whether the recovered NRBC were derived from the fetus, we attempted prenatal diagnosis by the fluorescence in situ hybridization (FISH) technique in 12 women pregnant with a male fetus (determined later by ultrasound) at between 8 and 16 weeks of gestation. Among the four devices used in the basic study of the high molecular filter method, NWC-2 had the best recovery rate. Therefore, we compared the numbers of NRBC recovered by the lectin method after preliminary concentration with NWC-2 or by Ficoll centrifugation, and found that the mean recovery rate of NWC-2 was 4.2 ± 5.0 times as high as that of the Ficoll method, indicating that the NWC-2 filter method is superior as a preliminary concentration method. Next, FISH analysis of the 12 pregnant women with a male fetus for the Y chromosome showed that 19.5 ± 12.8 NRBC were recovered, in 12.7 ± 8.1 (63.6%) of which a Y signal was confirmed, suggesting the NWC-2 filter method can be applied to prenatal diagnosis. We consider the filter–lectin method to be a superior method for isolation and recovery of NRBC in the maternal blood which can be applied to prenatal diagnosis.
ABSTRACT The toxicity of oral 2,4,6-trinitrophenol (TNP) was determined in newborn rats, and compared with that in young rats. In newborn rats, males and females were given TNP at 0, 16.3, 81.4 or 407 mg/kg per day on postnatal days (PND) 4–17 for the dose-finding study, and at 0, 4.1, 16.3 or 65.1 mg/kg per day on PND 4–21 for the main study. Deaths, lower body weight (BW) and behavioral changes were found at 81.4 and 407 mg/kg per day in the dose-finding study, and lower BW was observed in males at 65.1 mg/kg per day during the dosing period of the main study. In young rats, 5-week-old males and females were given TNP at 0, 20, 100 or 500 mg/kg per day for 14 days as the dose-finding study and at 0, 4, 20 or 100 mg/kg per day for 28 days as the main study. Deaths were observed at 500 mg/kg per day in the dose-finding study. Deaths or changes in BW were not found at 100 mg/kg per day or less. At 100 mg/kg per day, hemolytic anemia and testicular toxicity were found. In conclusion, toxicity profiles induced by TNP were markedly different between newborn and young rats.
ABSTRACT Primitive neuroectodermal tumors (PNET) are classified as the embryonal tumors developed in the brain, except for the cerebellum. Although many studies have been reported, the origin and pathogenesis of PNET are still unclear. In this study, we observed the development of undifferentiated tumors indistinguishable from PNET in the transgenic mice which expressed simian virus 40 T antigen (SV40-Tag) selectively in the oligodendroglia under the control of mouse myelin basic protein gene promoter. These PNET-like tumors reproducibly developed in the brain stem of the founder mice and the transgenic progeny derived from one founder mouse. Oligodendroglia-specific expression of SV40-Tag in these transgenic mice was observed by immunohistochemical analysis. Furthermore, expression of the oligodendroglia-specific marker genes was decreased in the tumors as well as in the transgenic brains. These findings suggested that tumors developed in transgenic mice were indistinguishable from PNET, and one of them showed oligodendroglia-like characteristics. Consequently, this transgenic line is a useful animal model to study the pathogenesis of undifferentiated tumor.
ABSTRACT CBFB at 16q22 heterodimerizes with either RUNX2 (also known as CBFA1) or RUNX1 (CBFA2) to activate the transcription of downstream molecules. RUNX2 regulates osteoblast differentiation and chondrocyte maturation and its haploinsufficiency leads to cleidocranial dysplasia, characterized large fontanelles, hypoplasia or aplasia of the clavicles, hypoplasia of the distal phalanges, and a wide pubic symphysis. Complete loss of Runx1 or Cbfb in mice is lethal because of the absence of fetal liver hematopoiesis. Fetal rescue in Cbfb–/– mice by providing the Cbfb functions in the hematopoietic progenitors leads to wide fontanelle and delayed chondrocyte maturation, presumably resulting from the incomplete function of the transcriptional pathway mediated by the Cbfb-Runx2 heterodimer. The present report describes a patient with a small deletion of chromosome 16q22.1 encompassing CBFB. Skeletal abnormalities included a widely open fontanelle, multiple wormian bones along the sagittal suture, hypoplasia of the distal phalanges, and mildly shortened clavicles. G-banding analysis revealed a shortening of the 16q22.1 band. A fluorescence in situ hybridization analysis, using the BAC probe spanning the CBFB locus at 16q22.1, revealed that the CBFB probe hybridized to only one of the two homologous chromosome 16 regions. Array-comparative genomic hybridization analysis revealed that the deletion spans 1.2 megabases. In reviewing eight previously reported cases of 16q interstitial deletions involving band q22, large cranial sutures were noted in all but one case. Considering the phenotypic similarity of the 16q22 deletion case and Cbfb–/– mice rescued for hematopoiesis and the consistency of the phenotype among 16q22 deletion cases, we suggest that the common phenotypic feature of the 16q22 deletion, large fontanelles, can be attributed to a haploinsufficiency of CBFB.