Search PubMed⌕ Search

Biomedical subjects

S Kohsaka

Publications and source records attributed to S Kohsaka.

At least 163 records · Page 9Linked to original sources

Immunohistochemical studies on mouse cerebral cortex grafted into the third ventricle of rats treated with cyclosporin A.

Newborn mouse cerebral cortex was transplanted into the third ventricle of an adult rat brain. After the operation, the immunosuppressant cyclosporin A was administered daily for two weeks, and the grafted tissue was examined immunohistochemically at the 4th week. Neurons, astroglias and oligodendroglias were positively stained by antibodies against neurofilament, glial fibrillary acid protein and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), respectively. The CNPase staining indicated that myelination had occurred in the grafted tissue. Thus both neuronal and glial elements in the grafted tissue could survive and mature in the third ventricle of the different species upon administration of cyclosporin A.

Animals↗

Cyclosporin A enhances the survivability of mouse cerebral cortex grafted into the third ventricle of rat brain.

The effect of the immunosuppressant cyclosporin A on the survivability of newborn mouse cerebral cortex transplanted into the third ventricle of adult rats was investigated. Hematoxylin staining revealed that the transplanted mouse brain tissue was rejected by 4 weeks after the transplantation in the control group. In contrast, a large mass of grafted tissue was clearly detected in the third ventricle even 4 weeks after the transplantation in the cyclosporin A-treated group, and the grafted tissue was heavily stained with Thy-1.2 mouse monoclonal antibody. The results indicate that cyclosporin A is an effective immunosuppressant in neuronal transplantation as well as in transplantation of other organs.

Animals↗

Effects of glycoprotein synthesis inhibitor on myelination in rat cerebellum.

Effects of a glycoprotein synthesis inhibitor on myelination were investigated in rat cerebellum. The glycoprotein synthesis inhibitor, tunicamycin (TM), was injected intracranially into newborn rats. The activity of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) in the cerebellum was significantly reduced in 2-week-old animals and was restored to the normal level by age 3 weeks. When TM was injected into newborn rats every 3-4 days for a total of 6 times, CNPase activity was still low at 3 and 4 weeks. Immunohistochemical stainings for CNPase and myelin-associated glycoprotein (MAG) were performed on paraffin sections of multiple-TM-injected cerebellum at 3 weeks. The intensity of the staining with MAG antiserum in the white matter was clearly decreased in TM-treated cerebellum compared with the control. The myelin in the granule cell layer was poorly stained with CNPase antiserum in TM-treated cerebellum. Subcellular fractionation was carried out and the CNPase activity in each fraction was measured. The CNPase activity in the myelin fraction (P2A) from the TM-treated cerebellum was significantly lower than that in the control. In contrast, the activity in the synaptosomal (P2B) and microsomal (P3) fractions from the multiple-TM-injected cerebellum was higher than in those from the controls. Polyacrylamide gel electrophoretic patterns of the P2A fractions were analyzed. The P2A fraction from TM-treated cerebellum contained less Wolfgram protein than the control. These results suggest that glycoprotein synthesis plays certain roles in myelination in the central nervous system.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

Disorders in myelination in the twitcher mutant: immunohistochemical and biochemical studies.

The twitcher is an autosomal recessive mutant mouse characterized by absence of galactosylceramidase. The twitcher shows clinical and histological features similar to those of human Krabbe-type leukodystrophy. We here present the results of a neurochemical and immunohistochemical analysis of the twitcher. Electrophoretic analysis revealed that in the particulate fraction of the spinal cord, myelin basic proteins (MBP) and proteolipid protein were decreased, and in the sciatic nerve fibers, PO protein, X, Y and MBP were clearly decreased. 2',3'-Cyclic nucleotide 3'-phosphodiesterase (CNPase) activities of the pallium cerebri, brain stem and spinal cord of the twitcher were about 20% less than those of the control. However, in the sciatic nerve, the activity was half that of the control. Immunohistochemical studies were carried out by means of antisera against MBP and CNPase. There were clear patches indicating both MBP- and CNPase-negative reactions in the white matter of the central nervous system from the twitcher. The reaction on the section of sciatic nerve fibers from the twitcher showed a positive reaction only in a very limited number of fibers with both MBP and CNPase antisera. A clear astrocytic hypertrophy was detected by the antiserum against glial fibrillary acidic protein (GFAP). Even in the grey matter of the cerebral cortex, strong GFAP-positive astrocytes were clearly observed.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗

Impaired development of rat cerebellum induced by neonatal injection of the glycoprotein synthesis inhibitor, tunicamycin.

The effects of the protein glycosylation inhibitor tunicamycin on the postnatal development of the rat cerebellum were examined in vivo. Tunicamycin (0.2 micrograms) was injected intracranially into 1-day-old rats. Inhibition of glycosylation of the macromolecules in the cerebellum by tunicamycin treatment was suggested by a reduced incorporation of [3H]glucosamine into the trichloroacetic acid (TCA)-insoluble fraction. The tunicamycin treatment did not affect gain in body weight significantly. However the cerebellar weight was significantly reduced by 30-40% compared with that of the controls. Development of GABAergic and cholinergic innervations in the hypoplastic cerebellum was examined by measuring the activities of glutamate decarboxylase (GAD) and choline acetyltransferase (ChAT). The specific activity and the total activity of GAD were significantly reduced in the tunicamycin-treated cerebellum. In contrast the specific activity of ChAT was significantly increased, whereas the total activity of ChAT per cerebellum was identical with that of the controls. These results suggest that the intracranial injection of tunicamycin affects the postnatal development of rat cerebellum, such as GABAergic and cholinergic innervations.

Animals↗

Immunohistochemical localization of 2',3'-cyclic nucleotide 3'-phosphodiesterase and myelin basic protein in the central nervous system of the jimpy and the normal mouse.

We describe the immunohistochemical localization of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and myelin basic protein (MBP) in CNS of the jimpy mutant mouse which is characterized by dys- and demyelination. In controls, the CNPase and MBP were localized exclusively in white matter in the CNS. The jimpy mutant mice were severely affected: A very weak reaction was observed in the white matter. Very few CNPase- and MBP-positive myelin sheaths were observed, and some degradation products were also observed after reaction with antisera against both CNPase and MBP. The immunohistochemical reaction in the jimpy mice showed a similar localization in both CNPase and MBP.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

Clonazepam monotherapy for epilepsy in childhood.

Sixty patients (age-range one month to 14 years) with other types of epilepsy than infantile spasms were treated with clonazepam. Disappearance of seizures and normalization of abnormal EEG with disappearance of seizures were recognized in 77% and 50%, respectively. Seizures disappeared in 71% of the patients with generalized seizures and 89% of partial seizures. Improvement of abnormal EEG was noticed in 76% of diffuse paroxysms and in 67% of focal paroxysms. In excellent cases, mean effective dosages were 0.086 +/- 0.021 mg/kg/day in infants and 0.057 +/- 0.022 mg/kg/day in schoolchildren, this difference was statistically significant (p less than 0.005). The incidence of side effects such as drowsiness and ataxia was only 5%.

Adolescent↗

Immunohistochemical study on oxytocin-like substance in the human placenta.

Our previous studies have demonstrated that a large quantity of oxytocin (OT)-like substance exists in human placental tissue. In the present study, the localization of the OT-like substance in the human placenta was investigated by the PAP (peroxidase and antiperoxidase complex) immunohistochemical method. The results demonstrated that the site of syncytiotrophoblast was positively stained by specific antiserum to OT, whereas the tissue was not significantly stained by normal rabbit serum (NRS). These results suggest that the OT-like substance might be localized in syncytiotrophoblast of the placental tissue.

Cross Reactions↗

Familial clustering of situs inversus totalis, and asplenia and polysplenia syndromes.

We report on a family in which a male infant had the asplenia syndrome, a younger brother had the polysplenia syndrome, and their father had situs inversus totalis. The occurrence of the asplenia and the polysplenia syndromes in a sibship of the present family and in two other previously reported sibships indicates that the two syndromes are causally and pathogenetically related to each other. If it is assumed that the father had an incomplete form of the polysplenia complex, then the condition in this family either is an autosomal dominant trait or is multifactorially determined.

Adult↗

Immunohistochemical localization of 2',3'-cyclic nucleotide 3'-phosphodiesterase and myelin basic protein in the chick retina.

Antisera against bovine 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and against chick myelin basic protein (MBP) were raised in New Zealand white rabbits. The specificity of CNPase antiserum was examined by Ouchterlony double-immunodiffusion test and immunoadsorption assay. With use of the specific antiserum, immunohistochemical localizations of CNPase and MBP were investigated in the chick retina. Light microscopic immunohistochemical studies have shown that MBP is localized in the optic nerve fiber layer and that CNPase is localized in the optic nerve fiber and photoreceptor layers. Electron microscopic immunohistochemical examinations demonstrated that the myelin-like neural sheaths in the optic nerve fiber layer were clearly stained by both antisera, whereas the membranes of the Müller cell were not stained. In the photoreceptor layer, membranes of the inner and outer segments of rod and cone photoreceptor cells were intensely stained by CNPase antiserum. However, these portions were not stained by MBP antiserum. Membranes of bipolar cells, amacrine cells, horizontal cells, and ganglion cells were not stained by either antiserum.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

Dissociation of enhanced ornithine decarboxylase activity and optic nerve regeneration in goldfish.

The significance of a previously observed increase in retinal ornithine decarboxylase (ODC, EC 4.1.1.17) following optic nerve crush was investigated in goldfish using a specific irreversible inhibitor of ODC, alpha-difluoromethylornithine (DFMO). Retinal ODC activity and putrescine levels were reduced 80% and 40%, respectively, by intraperitoneal injection(s) of DFMO. In fish in which the right optic nerve was crushed and DFMO was injected at the time of crush, at 2 days and at 4 days later, retinal ODC levels were maximally decreased after the third injection and returned to normal levels by 14 days post-crush (PC). Retinal tubulin synthesis was examined at 10 days PC. No difference in the post-crush/normal ratio of tubulin synthesis was observed between saline-injected and DFMO-injected groups. Neuritic extension was also examined in retinal explant cultures from 11-day PC retina. The neuritic growth index of DFMO-treated retinas did not differ from that of control retinas. Behavioral studies revealed no difference in the rate of recovery of vision between the two groups. Similar results were obtained in experiments using fish maintained in a 0.1% DFMO solution. These results suggest that the increase in retinal ODC associated with nerve crush does not play a causal role in restoration of function.

Animals↗

Effects of bovine growth hormone on the retarded cerebral development induced by neonatal hydrocortisone intoxication.

In comparison with normal controls, hydrocortisone-intoxicated rats (HC rats) had smaller cerebra, lowered 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) activity, and greatly reduced learning ability. The reduction in cerebral weight and DNA content was considered to be caused by a decrease in the number of proliferating glial cells, because the usual postnatal elevation of thymidine kinase (TK) activity was found to be suppressed in the cerebra from the HC rats. Electron microscopic observation of the pituitary gland revealed that the 5-day-old HC rat contained growth hormone (GH) secretory cells which were fully packed with GH granules, suggesting a disorder in the system which releases GH. In an attempt to promote cerebral development in the HC rats, we administered bovine GH (bGH) to some of the HC rats daily from the day of birth until weaning (HC + bGH rats). In the HC + bGH rats, the cerebral DNA was restored to normal levels and a concomitant increase in TK and CNPase activity was noted. Furthermore, in the brightness discrimination test, whereas the HC + bGH rats attained the learning ability of the normal controls after only 10 sessions, the HC rats were unable to reach an equivalent level even after 25 sessions.

Animals↗

Neurochemical and morphological studies on the myelin of peripheral nervous system from Shiverer mutant mice: absence of basic proteins common to central nervous system.

Shiverer mouse is characterized by poor lamella formation and absence of major dense line in the CNS myelin. PNS of the Shiverer was normal with regard to myelin lamellar formation, immunohistochemical staining of the Schwann cells by S-100 protein, and the activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase. Analysis of the purified myelin by SDS-polyacrylamide gel electrophoresis revealed that P1 and Pr, which are common to BP in CNS, and PM protein were missing, while P0 and P2 proteins were of the same level as the control.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

Increased activity of ornithine decarboxylase in goldfish following optic nerve crush.

Ornithine decarboxylase (ODC) activity increased in goldfish retina, brain, and kidney several days following unilateral intraorbital optic nerve crush. Activity in both retinas followed a similar time course, an elevation being first detectable 3 days following crush, maximal on day 5 and returning to control levels by day 7. Increases were significantly higher in the retina on the lesioned side than in control retina. If one eye was surgically removed, a more prolonged elevation of ODC activity was seen in the remaining eye than was observed in control retinas following contralateral nerve crush. Sham operation or behavioral stress secondary to aversive electrical shock did not lead to significant increases in ODC activity in brain or retina. Explants of retinas whose optic nerve had been crushed 10--14 days prior to explantation, as well as those derived from the unlesioned side, showed increases in ODC activity following addition of beta-NGF to the medium. The response was greater in post-crush retinas than in control retinas. These results taken together suggest an increased responsiveness of the regenerating retina to stimuli that lead to increased ODC activity. While the nature of the in vivo signal(s) may be complex, it is inferred that degenerative changes in the distal stump play a significant role.

Animals↗

Ornithine decarboxylase activity in retinal explants of goldfish undergoing optic nerve regeneration.

Retinal explants cultured in the presence of fetal calf serum (FCS) exhibit an increase in the activity of ornithine decarboxylase which is maximal several hours after explantation. The measured activity of this enzyme is higher in explants of retinas whose optic nerve had been crushed several days previously (post-crush, PC) than in control (normal, N) retinas. The addition of rabbit antibodies against nerve growth factor (NGF) to the incubation medium does not block this stimulatory effect of FCS, a result suggesting that factors other than NGF present in FCS are responsible for the observed stimulation. An inhibitor of ODC synthesis, diaminopropane (DAP), and an irreversible inhibitor of ODC activity, alpha-DL-difluoromethylornithine (alpha-DFMO), each suppressed the FCS-stimulated ODC activity when added to the culture medium. Since FCS addition also promotes neuritic outgrowth from PC goldfish retinal explants, we explored the possible relationship of the stimulated ODC activity and the ability of explants to extend neurites. Concentrations of DAP or alpha-DFMO that block ODC activity also suppress neuritic outgrowth. Possible non-specific actions of the drugs unrelated to the block of ODC are examined. While the increases in OCD activity seen in PC and N goldfish retinas explanted into FCS-containing medium may be a requisite, they cannot be sufficient to support neuritic outgrowth. Intrinsic changes in the retinal explant secondary to crush of its optic nerve as well as factor(s) present in FCS that may be unrelated to the stimulation of ODC activity also appear necessary for neuritic outgrowth.

Animals↗