Cognitive deficit in 7-year-old children with prenatal exposure to methylmercury

A cohort of 1022 consecutive singleton births was generated during 1986-1987 in the Faroe Islands. Increased methylmercury exposure from maternal consumption of pilot whale meat was indicated by mercury concentrations in cord blood and maternal hair. At approximately 7 years of age, 917 of the children underwent detailed neurobehavioral examination. Neuropsychological tests included Finger Tapping; Hand-Eye Coordination; reaction time on a Continuous Performance Test; Wechsler Intelligence Scale for Children-Revised Digit Spans, Similarities, and Block Designs; Bender Visual Motor Gestalt Test; Boston Naming Test; and California Verbal Learning Test (Children). Clinical examination and neurophysiological testing did not reveal any clear-cut mercury-related abnormalities. However, mercury-related neuropsychological dysfunctions were most pronounced in the domains of language, attention, and memory, and to a lesser extent in visuospatial and motor functions. These associations remained after adjustment for covariates and after exclusion of children with maternal hair mercury concentrations above 10 microgram(s) (50 nmol/g). The effects on brain function associated with prenatal methylmercury exposure therefore appear widespread, and early dysfunction is detectable at exposure levels currently considered safe.     

Transparent Nano-Composites Ceramics by Annealing of Amorphous Phase in the HfO2-Al2O3-GdAlO3 System

We have succeeded in fabricating transparent nano-structured ceramics by annealing of the amorphous phase obtained by the solidification of the eutectic melt in the ternary system HfO₂− Al₂O₃− GdAlO₃. The ceramics annealed at 1273 K for 6 hr contained 5-10-nm cubic hafnia grains, and those annealed at 1273 K for 72 hr contained both cubic hafnia and gadolinium aluminum garnet grains 5-10 nm in size. They showed high transparency. Annealing at 1473 K, however, resulted in grain growths that brought about non-transparency.     

Novel properties of new type conducting and insulating polymers andtheir composites

Novel properties of recently developed conducting and insulating polymers and their composites are discussed. Properties of conducting polymer whose main chains are composed of unsaturated π-bonds depend strongly on the main chain structure, substituent and also molecular dopants. Various applications of conducting polymers such as electroluminescence (EL) elements, electrolyte capacitors, photoconductors, photovoltaic cells, superconductors and insulators at cryogenic temperature, are discussed by taking effects of molecular dopants such as C₆₀ into consideration. A new type of insulating polymer, syndiotactic polypropylene prepared by newly developed metallocene catalysts has been studied and found to exhibit much superior electrical, thermal and mechanical characteristics compared with those of conventional isotactic polypropylene, atactic polypropylene and polyethylene. These excellent characteristics originate from lower crystallinity, smaller spherulites and different crystal lattice than in isotactic polypropylene. Negligible degradation of syndiotactic polypropylene by contact with copper is interpreted in terms of difference of catalysts and suppression of diffusion of copper cation. New types of conducting polymer, insulating polymer composites were prepared. Their conductivity was controlled over more than 10 orders of magnitude by small amounts of a conducting polymer, polypyrrole, which can be interpreted in terms of the percolation model depending on the shape and density of polypyrrole coated insulating polymer particles. Nonlinear current-voltage characteristics were also studied     

Spinal meningeal melanocytoma presenting with superficial siderosis of the central nervous system. Case report and review of the literature

1. We recently demonstrated that intrathecal administration of prostaglandin E2 (PGE2) and PGF2alpha induced allodynia through a pathway that includes the glutamate receptor and nitric oxide (NO)-generating systems from pharmacological studies. In order to clarify the involvement of NO in prostaglandin-induced allodynia, we measured NO released from rat spinal cord slices by a chemiluminescence method. 2. PGE2 stimulated NO release from both dorsal and ventral regions all along the spinal cord. PGE2 stimulated the release within 10 min and increased it in a time-dependent manner. 3. The PGE2-induced NO release was observed at 100 nM-10 microM. PGF2alpha stimulated the release at concentrations higher than 1 microM, but PGD2 (up to 10 microM) did not enhance it. 4. 17-Phenyl-omega-trinor PGE2 (EP1 > EP3) and sulprostone (EP1 < EP3) were as potent as PGE2, but PGE1 was less potent, in stimulating NO release. While M&B 28767 (EP3) did not enhance the release, butaprost (EP2) stimulated it at 1 microM. The PGE2-evoked release was blocked by ONO-NT-012, a bifunctional EP1 antagonist/EP3 agonist. 5. The PGE2-evoked release was Ca2+-dependent and blocked by MK-801 (NMDA receptor antagonist) and L-NAME (NO synthase inhibitor). The release was also inhibited by PGD2 and dibutyryl-cyclic AMP. 6. The present study demonstrated that PGE2 stimulates NO release in the rat spinal cord by activation of NMDA receptors through the EP1 receptor, and supports our previous findings that the NO-generating system is involved in the PGE2-induced allodynia.     

The volume and pH of gastric fluid in elective surgical patients after preoperative oral fluid intake

The effect of preoperative oral fluid intake on the volume and pH of gastric fluid was examined in 45 elective surgical patients ranged in ages from 18 to 70 years. Two hours preoperatively they all received oral roxatidine 75 mg with 10 ml water, immediately followed by 150 ml oral water or 150 ml refreshing drink or no fluid as control. Just after the induction of anesthesia, a Salem-sump tube was put down to the stomach to collect gastric fluid in each patient. The volume and pH of gastric fluid taken were 10.9 +/- 7.9 ml, 16.3 +/- 2.3 in control group, 8.0 +/- 6.0 ml, 6.2 +/- 2.4 in the water group and 6.3 +/- 6.0 ml, 7.1 +/- 1.7 in the refreshing drink group. As there were no significant differences in gastric pH values in the three groups, the highest value was found in the refreshing drink group. No significant difference in VAS of hungry and thirsty feeling was found among the three groups. We conclude that preoperative oral water or refreshing drink with roxatidine 75 mg 2 hours before the start of anesthesia may not increase the risk of aspiration during the induction of anesthesia.     

Effect of sodium tauroursodeoxycholate (UR-906) on liver dysfunction in bile duct-ligated rats

We investigated the effect of sodium tauroursodeoxycholate (UR-906) on cholestasis in common bile duct-ligated rats in comparison with the effect of dehydrocholic acid. UR-906 (30-180 mumol/kg) and dehydrocholic acid (180 mumol/kg) were intravenously given once daily for consecutive 20 days in rats and the common bile duct was ligated for the last 10 days. On the next day after the last test drug administration, serum biochemical and plasma hemostatic variables were determined. UR-906 significantly ameliorated the elevation of serum cholesterol, phospholipid, bilirubin and bile acid concentrations in bile duct-ligated rats. UR-906 significantly suppressed the prolongation of plasma prothrombin time and activated partial thromboplastin time. Furthermore, UR-906 significantly suppressed the decreases in plasma coagulation factor II and X activities. However, dehydrocholic acid did not cause significant changes in any of the variables examined in this model. These results suggest that UR-906 has a beneficial effect against cholestasis induced by bile duct ligation in rats and that this drug may be useful in the treatment of clinical cholestatic disorders.     

Time‐frequency analysis of a pressure wave caused by impulse tree using wavelet transform

This paper describes results of time‐frequency analysis of a pressure wave caused by impulse tree extension using wavelet transform. Pressure waves were measured by a piezo sensor which was located on the back of the plane electrode when high‐voltage nanosecond pulses were applied to a point electrode in a low‐density polyethylene block. Frequency of the pressure wave from induced charges on the plane electrode was higher than that of the pressure wave from tree. In addition, the frequency of the pressure wave from tree tended to decrease with increasing gap length because of the dispersion of the pressure wave during its propagation. When a large tree extension occurred between a 5‐mm gap, pressure waves of about 10 MHz propagated from the tree tip and a pressure wave of 1 MHz propagated from the tree stem. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 1–7, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10097     

Is angiographic spasm real spasm?

Systematic morphological study of the cerebral arteries was made in six autopsy cases of ruptured aneurysms. The time course of the arterial luminal narrowing was observed by repeated angiograms, and segments of the narrowed arteries were studied histologically. Various histological changes were found consistent with the angiographic findings. We have devided these into three stages according to the duration of the disease. In the acute stage (less than one day) the contraction of the medial smooth muscle cells may be the main cause of the luminal narrowing. In the subacute stage, arteries showed a reduction in lumen size with medial thickening, marked corrugation of the internal elastic lamina, and thrombus formation attached to the endothelial surface. If vasoconstriction remained localized to the same segment for several days, the intimal or medial thickening and thrombus might produce the luminal narrowing consistent with the angiographic narrowing. In the chronic stage (more than two weeks), most cases showed dilatation of the arterial lumen on angiography. These arteries showed frank necrosis of the smooth muscle cells histologically. In a case which demonstrated progressive luminal narrowing on angiograms over 2 weeks, the arterial wall showed luminal narrowing with cellulofibrous thickening of the intima and organization of the thrombus. The presence of these structural changes in the narrowed arteries seen at angiography seems to be very important for proper understanding and treatment of vasospasm.     

Hankel transform domain analysis of open circular microstrip radiating structures

A full-wave analysis of a circular disk conductor printed on a dielectric substrate backed by a ground plane is presented. The method is based on the Galerkin's method applied in the Hankel transform domain and is numerically quite efficient. Several numerical examples are compared with available experimental data. The agreement is found to be quite good and the validity of the present method is confirmed.