Mn SOD activity and protein in a patient with chromosome 6-linked autosomal recessive parkinsonism in comparison with Parkinson's disease and control

We report Mn superoxide dismutase (SOD) protein and activity in a patient with familial autosomal recessive Lewy body-negative parkinsonism in comparison with patients with sporadic Parkinson's disease (PD) and controls. We recently proved linkage of this family with markers of chromosome 6 at 6q25.2-27, which included the Mn SOD gene. We used a novel polymorphic mutation at -9 position of the signal peptide of the Mn SOD precursor protein, which caused valine to alanine substitution. All the affected members of this family showed homozygosity for alanine, whereas nonaffected members, sporadic PD patients, and the control subjects studied showed either heterozygosity of alanine and valine or homozygosity of valine. The Mn SOD activity of this familial patient was the highest among the PD patients and the control subjects studied, and an abundant expression of Mn SOD was found in the substantia nigra. The molecular weight of Mn SOD protein by Western blotting of this patient was essentially similar to that of PD patients and the control subjects. High Mn SOD activity may constitute a genetic risk factor in this familial patient. The difference in the signal peptide sequence may affect the expression of Mn SOD within mitochondria; however, it is unlikely that loss of function type Mn SOD mutation is the cause of this familial parkinsonism. Mn SOD in sporadic PD patients was similar to that in controls.     

Changes in lipids in liver and serum of rats fed a histidine-excess diet or cholesterol-supplemented diets

The influence of dietary excess (5%) L-histidine on serum and liver lipids was examined in rats. Feeding a histidine-excess diet for 3, 6, 14 or 30 days caused growth retardation, hepatomegaly and decreased liver lipids throughout the period of the experiment. Hypercholesterolemia was observed after feeding a histidine-excess diet for 6 days; then serum cholesterol continuously increased for 30 days. Serum triglyceride on day 30 in rats fed the histidine-excess diet showed a significant decrease compared to rats fed the basal diet. Serum phospholipids of rats fed the histidine-excess diet for 7 or 14 days showed a significant increase compared to rats fed the basal diet. When rats were fed a basal, histidine-excess or cholesterol-supplemented diet (0.5% and 1.0% cholesterol) for 6 days, the distribution of serum high density (HDL), low density (LDL) and very low density lipoprotein cholesterol in rats fed the histidine-excess diet was similar to that of rats fed the basal diet, whereas LDL-cholesterol increased and HDL-cholesterol decreased in rats fed the cholesterol-supplemented diet.     

Catechol-O-methyltransferase genotype and susceptibility to Parkinson's disease in Japan. Short communication

We report -108Met/Val polymorphism of the COMT gene in Japanese patients with Parkinson's disease (PD). The allele frequency for -108Val was higher in PD patients compared with controls, although the differences did not reach the statistical significance. However, the frequency of -108Val homozygotes was significantly higher in PD patients (56.8%) than in control subjects (44.2%), and heterozygotes of -108Met/Val were less in PD. COMT gene polymorphism may constitute a genetic risk factor for PD among Japanese.     

Cholesterol synthesis and degradation in normal rats fed a cholesterol-free diet with excess cystine

Feeding a diet with excess cystine to rats resulted in hypercholesterolemia. To understand the mechanism of the hypercholesterolemia’ cholesterol synthesis and degradation’ bile acid content of bile’ and fecal steroids were determined. The in vivo incorporation of tritiated water into hepatic cholesterol’ and activity of hepatic 3-hydroxy-3-methylglutaryl-CoA reductase in rats fed a high-cystine diet were significantly higher than those in rats fed a control diet. The activity of hepatic cholesterol 7α-hydroxylase was similar between two groups. Little effect of cystine supplementation was found on fecal sterol excretion although there were some changes in biliary excretion of cholic acid derivatives. These results indicate that hypercholesterolemia caused by feeding of a high-cystine diet may be due to the stimulation of hepatic cholesterol synthesis.     

The effect of a histidine-excess diet on cholesterol synthesis and degradation in rats

Feeding a diet high in excess histidine (5% L-histidine) resulted in hypercholesterolemia and enlargement of the liver in rats. To clarify the mechanism of the hypercho-lesterolemia cholesterol synthesis and degradation were followed. We found that hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity in histidine-excess diet rats was significantly higher than in rats fed a basal diet. Incorporation of [³H]water into cholesterol of liver slices from rats fed the histidine-excess diet was higher than incorporation into liver slices from rats fed the basal diet (expressed per liver per 100 g body weight).In vivo incorporation of [³H]water into hepatic cholesterol was also higher, but the incorporation into cholesterol of the small intestine was lower in histidine-fed rats than in rats fed the basal diet (expressed per liver per 100 g body weight). Hepatic cholesterol 7α-hydroxylase activity was similar in both groups. The data suggest that the hypercholester-olemia caused by histidine-excess diet appears to be due to the stimulation of cholesterol synthesis in the liver.     

美国公园管理的最新发展趋势

最近,围绕公园管理这个课题正在不断地出现新的发展趋势.以介绍在纽约召开的大都市大公园会议议程内容的形式,就日本国内外所面临的公园管理发展趋势进行讨论.     

Automotive Application of Advanced Superalloys

Based on the testing reported here, a new Ni-based superalloy has been adopted for use in Mazda RX-7 heat-resistant turbochargers. The new alloy exhibits a high temperature stability of the γ phase, resisting the initial stage of creep rupture. Casting parameters and chemistries are varied to produce a directionally solidified columnar structure, which eliminates internal grain boundary rupture sites. The Mazda super-high temperature turbocharger was used to achieve a world speed record (GT-C class) of 238.442 mph at Bonneville, Utah, last August.     

D-青霉胺的膳食剂量对大鼠体内铜锌代谢水平的影响

研究实验分别将0．1％,0．2％,0．3％,0．4％,0．5％和1．0％的口服D-青霉胺混合在膳食成分中让实验大鼠通过摄食自然摄取,旨在寻求一种更为简便和人道的治疗途径,并探讨其有效移除大鼠体内铜元素的最适膳食剂量．实验结果发现0．3％和0．4％D．青霉膳食可以显著地移除大鼠肝脏和血清中的铜元素,而且未发现明显的毒副作用,因此0．3％～0．4％被认为是D-青霉胺最适的膳食剂量．研究结果还表明铜和锌在大鼠肝脏内的代谢途径并不一致．     

Strain-induced crystallization of peroxide-crosslinked natural rubber

Effect of network-chain density (ν) on the strain-induced crystallization of peroxide-crosslinked natural rubber was studied by fast time-resolved synchrotron wide-angle X-ray diffraction. It was observed that the elongation ratio at the onset of strain-induced crystallization (α_c) became smaller with the increase of ν. The difference of the entropy between the undeformed and deformed states at each α_c was nearly equal in spite of the variation of ν. The calculated melting temperature at α_c of the samples was also almost the same regardless of their ν. These observations mean that the strain-induced crystallization occurred when the deformation brought about a definite entropic state for peroxide-crosslinked natural rubber. They agreed with the prediction by Flory and were consistent with the classical theory of rubber elasticity.