Intracranial accumulation of 99mTc-phosphorous compound on bone scintigraphy]

Bone scintigrams of 99mTc-phosphorous compound in 4,579 cases were reviewed concerning the intracranial accumulation. Intracranial accumulations were demonstrated in 8 cases (0.17%). The lesions with intracranial accumulation were two cases of primary brain tumor (1 meningioma and 1 astrocytoma), five cases of metastatic brain tumor (1 rectal cancer, 1 gastric cancer, 1 uterine cervical cancer and 2 lung cancers) and one case of cerebral infarction. Calcification was detected in one of eight cases on CT scans. It is important to pay attention to the intracranial accumulation on routine bone scintigram because brain tumor or infarction may be detected.     

Dextrorphan attenuates the behavioral consequences of ischemia and the biochemical consequences of anoxia: possible role of N-methyl-d-aspartate receptor antagonism and ATP replenishing action in its cerebroprotecting profile

The acute anti-ischemic and anti-anoxic effects of dextrorphan (DX) were compared with those of dizocilpine (MK-801) in a variety of animal models, and in vivo and in vitro testings under anoxic conditions. DX reduced the incidence of death in ischemic mice and improved the rotarod performance of mice with brain ischemia. The ischemically-impaired memory of mice treated with DX markedly improved, as shown in the step-through type passive avoidance test, Morris water maze and in the habituation of exploratory behavior test. MK-801 likewise improved the water maze performance of the ischemically-impaired mice, but to a lesser extent. The step-through type passive avoidance performance of ischemic mice was not improved by MK-801. In the passive avoidance task with normal mice, DX, like MK-801, produced anterograde amnesia at doses higher than those needed to attenuate the behavioral effects of ischemia. DX, intravenously or centrally administered, markedly and dose-dependently reduced the incidence of death in mice receiving potassium cyanide (KCN). DX lessened the reduction in adenosine triphosphate (ATP) and increased lactate contents in mice dosed with KCN and also lessened the reduction in ATP in the TCA cycle and oxidative phosphorylation reactions caused by KCN (0.58 mmol/l), whereas MK-801 failed to show any effect on ATP formation pathways in vivo and in vitro, and failed to protect mice against KCN-induced lethal toxicity in vivo. In the in vitro studies, DX increased the adenylate kinase activity of the rat brain homogenate. DX was found to be a cerebroprotectant with anti-ischemic and anti-anoxic actions, the effects probably stemming from its N-methyl-d-aspartate receptor antagonistic property in cooperation with its ATP replenishing action.     

Cystatin C and apolipoprotein E immunoreactivities in CA1 neurons in ischemic gerbil hippocampus

The distribution patterns of cystatin C and apolipoprotein E (apo E) were studied immunocytochemically in the gerbil hippocampus before and after 5 min ischemia. In the controls, cystatin C was distributed mainly in astrocytes. In addition, a large number of dots positive for cystatin C were observed around the outlines of neuronal perikarya in the CA1 subfields. One day after ischemia, cystatin C-positive stainings outlining neuronal cell bodies disappeared. On the fourth day, intense stainings for cystatin C appeared in atrophied pyramidal neurons and these stainings in neurons disappeared by the 14th day. A remarkable increase in the number of cystatin C-positive astrocytes occurred on the fourth day and thereafter these spread over the whole of the CA1 subfield. Apo E was also distributed in astrocytes in the control specimens. From the fourth day, extra- and/or intracellular distribution of apo E-immunoreactivities was noted in the stratum pyramidale. Apo E-positive astrocytes disappeared transiently on the fourth day and then reappeared and increased remarkably by the 14th day. These findings indicate that cystatin C and apo E are involved in the degeneration process of brain neuronal cells.     

Source estimation of spontaneous MEG activity and auditory evoked responses in normal subjects during sleep

Summary This study focuses on source estimation of spontaneous MEG activity and auditory evoked responses during sleep. Sources of K-complexes and auditory evoked responses were investigated by magnetoencephalograph (MEG) and electroencephalograph (EEG) measurements, simultaneously. Sources of K-complexes during stage 2 sleep were investigated. The MEG results suggested that the sources of K-complexes can be modeled by two current dipoles. Dipoles for the K-complexes were estimated to be located 5 mm away from the sources of the N100 components of auditory evoked responses during wakefulness. Sources of auditory evoked responses during each sleep stage were also investigated to clarify the origins of the K-complex, the vertex sharp transient, and delta waves. Estimated dipoles for the N100 component for each sleep stage were estimated to be at slightly different locations in the auditory area. Based upon results of the MEG measurements and the EEG topographies, sources of the N330 component can be modeled by multiple current dipoles, which are seen to be distributed diffusely throughout the cerebral cortex.This work was supported in part by the grant 03505002, from the Ministry of Education Science and Culture, Japan.     

Magnesium intake and bone mineral density in young adult women

The purpose of this study was to determine a possible association between magnesium intake and bone mass in young adult women. Subjects consisted of 106 female university students aged 19-25 years. Calcium and magnesium intakes were evaluated using the duplicate sampling method on three weekdays. Spinal and femoral bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. Mean magnesium intake was 139 mg/day (median 127, SD 54). The correlation between magnesium intake and BMD was of borderline significance (r = 0.175, p = 0.073) for the femoral neck, and was insignificant (r = 0.084, p = 0.391) for the lumbar spine. However, the partial correlation between magnesium intake and BMD of the femoral neck (r = -0.027, p = 0.788), adjusted for calcium intake, was not significant. In conclusion, we did not find an association between magnesium intake and bone mass in young women, and calcium intake needs to be included as an important, potential confounding factor when exploring such an association.     

An incomplete cerebral ischemia produced a delayed dysfunction in the rat hippocampal system

We investigated whether functional changes occur with incomplete cerebral ischemia which do not lead to neural cell death. If functional changes are recognized, it is necessary to clarify whether they occur immediately after ischemia or after a lag of a few days similar to the pathological changes. Long-term potentiation (LTP) in both the Schaffer collateral-CA1 and the perforant path-dentate gyrus synapses in halothane-anesthetized rats were examined 1 day and 4 days after 10 min clamping of the bilateral common carotid arteries. LTP was substantially attenuated after clamping of the bilateral common carotid arteries. In Schaffer-CA1 synapses, the inhibition of LTP was significant on both the 1 day and 4 days after-clamping group. In perforant path-dentate gyrus synapses, LTP was significantly inhibited on only the 4 days after-clamping group. These results suggest that functional damages may occur with incomplete ischemia without any histological damages. In the 1 day after-clamping group, LTP was reduced, but the changes in LTP differed from the inhibition of the 4 days after-clamping group. Therefore, a so-called delayed dysfunction might exist in the hippocampal neurons, despite absence of pathological changes.     

Hepatic accumulation and hepatotoxicity of luteoskyrin in mice.

HPLC analysis revealed that luteoskyrin administered orally to male mice accumulated selectively in the liver, with minor distribution to the serum and kidneys. Elevation of serum GOT and GPT values was maximal 3 days after administration. In mice administered this mycotoxin intravenously, selective accumulation was also observed in the liver, and the half-life of hepatic luteoskyrin in males was significantly longer than that in females. Increment of serum transaminases was also marked in males with maximum accumulation at 24 h after administration. Histopathologically, cellular membrane damage was an early effect of luteoskyrin on cell necrosis, and these morphological changes were also marked in males. Luteoskyrin also elevated hepatic lipid peroxides, the maximum elevation being 8 h after injection; this increase was suppressed by alpha-tocopherol and Bi(NO3)3. HPLC-ECD analysis indicated that the level of 8-hydroxy-deoxyguanosine, one of the markers of hydroxy-radical-mediated modification of DNA guanine residues, was increased in hepatic DNA. These findings indicate that luteoskyrin has a high affinity for the liver, resulting in induction of lipid peroxidation, hepatocellular membrane damage, and elevation of serum transaminase activities. It is suggested that the hydroxy radicals derived from this anthraquinone contribute to these toxicological changes.     

Ultrastructural analysis of neurofibrillary tangles of Alzheimer's disease using computerized digital processing

Summary The ultrastructure of neurofibrillary tangles of Zlzheimer's disease was analyzed by computerized digital processing of electron micrographs. Processing of the electron micrographs consists of four steps: digitizing the electron micrograph, Fourier transformation, noise filtering and inverse Fourier transformation and Laplacian operation. In the present study, we have confirmed that neurofibrillary tangles are composed of a pair of helical filaments (PHF), which appear characteristically as an unbranched rigid structure. The periodicity of PHF is 78nm on the diffractogram. The dimensions of PHF obtained by our analysis, although basically similar to those described earlier by other investigators using conventional techniques, more precisely defines its structural conformation. We have also demonstrated that the spatial relationship of two filaments appears symmetrical after two-way tilting of the specimen about the axis of rotation. Our observations emphasize the importance of digital image processing as an effective tool for structural analytical research in biology and medicine.Supported in part by the Japanese Ministry of Culture (61570527) and the Research Committee on Senile Dementia of the Ministry of Welfare