Yutaka Nishijima

Metaphyseal fibrous defect (nonossifying fibroma) in the mandible: A case report

A 7-year-old boy presented in whom a metaphyseal fibrous defect was diagnosed. The lesion was enucleated under local anesthesia. The postoperative course was uneventful and there have been no signs of recurrence as of 14 months after operation. Although rare, metaphyseal fibrous defect should be included in the differential diagnosis of tumors arising in the jaws.

Peripheral acting muscle relaxants alter the effects of baclofen on the electrocorticograms in the rat

The effects of intraperitoneally administered baclofen on behavior and electrocorticograms (ECoG) were studied in freely moving and paralyzed rats. In the freely moving rats, 10 mg/kg of baclofen suppressed ECoGs with behavioral sedation, and 20 mg/kg caused whole body twitching accompanied with spike discharges in low voltage slow waves background. In the freely moving rats, baclofen acted as depressant in low dose and convulsant in high dose. In the paralyzed rat, 10 mg/kg of baclofen first suppressed ECoGs. Though fast waves components recovered with slow waves background in the ECoGs of rats paralyzed with gallamine (50 mg/kg) 3 hours after the baclofen injection, fast waves activities were not observed in the ECoG of rats paralyzed with succinylcholine (50 mg/kg), d-tubocurarine (3 mg/kg) or pancuronium (1mg/ kg). Under paralysis with d-tubocurarine, baclofen suppressed ECoG first, and then spike discharges started 90 min after the injection. These results suggest that the effects of baclofen on ECoG were different depending on the muscle relaxant used.

Age-related changes in nitric oxide content and nitric oxide synthase activity in senescence-accelerated mouse (SAMP8) brain

The senescence-accelerated mouse (SAM), where average lifespan is about 70% compared with other strains, was established as a murine model of accelerated aging (Takeda et al., 1981). SAM was selected from the sister-brother mating of AKR strain mice. The pattern of aging in SAM is that of accelerated senescence which begins after normal development, i.e., not related to premature aging or senescence. The SAM strains have been designated as SAMP1, SAMP2, SAMP3, SAMP4, SAMP6, and SAMP8 based on the signs of aging and gross lesions (Miyamoto et al., 1986). Because the SAMP8 strain exhibited inferior acquisition of learning from 4 months onwards with a low incidence of senile amyloidosis (Miyamoto et al., 1986), it was thought to be an excellent animal model of deficits in learning and memory. Though SAMP8 mice showed age-related memory and learning deficit which was linked to a deterioration in the ability of acquisition in multiple-trial passive avoidance response, their T-maze performances, which reflect working and reference memory, were essentially normal (Yagi et al., 1988). Because deficits in working and reference memories are thought to be closely related to septal and/or hippocampal damage (Stanton et al., 1984), SAMP8 are thought to have little or no damage in these areas (Yagi et al., 1988).

2-Guanidinoethanol increased dopamine release and 3,4-dihydroxyphenylacetic acid content, but not homovanillic acid content in the rat brain: electroneurochemical and enzymological studies.

The effects of 2-guanidinoethanol (GEt) on the release of monoamines and on the activity of their degrading enzymes were studied in order to investigate why 3,4-dihydroxyphenylacetic acid (DOPAC) increased to a much greater extent than homovanillic acid (HVA) after GEt injection into rat brain. In differential pulse voltammograms recorded using an electrochemically treated carbon fiber electrode, two distinct oxidation peaks, one at 130mV (DOPAC peak) and the other at 300 mV (5-hydroxyindoleacetic acid (5-HIAA) peak), were observed. In the hippocampus, the DOPAC peak increased markedly compared to the peak height recorded prior to the intracerebroventricular injection of GEt (6μmol). Although the DOPAC peak height increased to 350% 4 hours after GEt injection, the 5-HIAA peak showed no change. In the striatum, the DOPAC peak increased to 150% 3 hours after GEt injection. Serial changes in the extracellular levels of DOPAC, HVA, and 5-HIAA were monitored in the striatum after GEt injection, using an in vivo brain micro-dialysis technique. Although the DOPAC levels strated to increase 80 minutes after GEt injection, HVA and 5-HIAA levels showed no change. On the other hand, monoamineoxidase, which metabolizes dopamine to DOPAC, was not activated and catechol-0-methyltransferase, which metabolizes DOPAC to HVA, were not inhibited by 5 mM of GEt in vitro. These data suggested that GEt increased the release of dopamine, but not of serotonin, and that GEt might restrict the DOPAC transport system.

Pediatric acute lymphocytic leukemia with osseous changes in jaws: Literature review and report of a case

A case of acute lymphocytic leukemia (ALL) in a child is presented. We also reviewed the recent literature of similar cases describing leukemic jaw bones involvement in Japan. Radiographic examinations of the patient disclosed diffuse osteolytic changes of the entire jaws, the corticated border of the crypts of developing teeth, loss of lamina dura, a thickened periodontal space and disappearance of the radiopaque lines that delineate the borders of the mandibular canal. Pronounced regression and restoration of the alveolar bone and the crypts were detectable on the radiographs taken after a course of the treatment for ALL.An apparent radiographic change of jaw bone after the treatment indicates that the radiographic examinations of children with leukemia in the leukemic process are of quite diagnostic value.