Using the yeast prion as a model, we have developed a novel system to observe the growth of individual prion fibers directly. NM fragments, the prion-determining region of the yeast protein Sup35p, were labeled by either red or green fluorescent dyes, and the fiber growth was observed under a fluorescence microscope. When greenSup35NM was added to the preformed fibers made of red-Sup35NM, 70 -97% of green fibers grew unidirectionally, from only one end of individual red fibers, whereas the remainder grew from both ends. Similarly, the majority of red fibers grew from only one end of green fibers when the order of addition was reversed. Sonication of preformed fibers to expose fresh ends did not change the results, excluding a possibility of occasional deformation of one end as the reason of the apparent unidirectional growth. These results indicate the polarity of Sup35 prion fibers and impose constraints on the models of fiber growth.

For analysis of the cytokine network in Kawasaki disease (KD), we measured over time the plasma levels of interferon (IFN)-γ interleukin (IL)-4 and IL-10 in patients with KD. Fifteen patients with KD were studied. Eight healthy children were selected as control subjects. Circulating IFN-γ levels were measured by immunoradiometric assay, and IL-4 and IL-10 levels were measured by enzyme-linked immunosorbent assay. The results were as follows: (1) The plasma levels of IFN-γ in KD patients in the acute phase were significantly higher than the levels of patients in the convalescent phase (p < 0.05) and those of the control children (p < 0.05). (2) The plasma levels of IL-4 in the KD patients in the acute phase were significantly higher than the levels of the patients in the convalescent phase (p = 0.001) and those of the control children (p = 0.001). (3) The plasma levels of IL-10 in the KD patients in the acute phase were significantly higher than the levels of the patients in the convalescent phase (p < 0.03) and those of the control children (p < 0.005). (4) The investigation of the relationship between the IL-4 and IFN-γ levels during the acute phase of KD demonstrated a significant reciprocal relationship (p < 0.05). (5) There was no significant relationship between the IL-4 and IL-10 levels during the acute phase. However, plasma IL-10 levels were low in the patients with high levels of plasma IL-4, and the patients with high levels of IL-10 revealed low levels of plasma IL-4. The above results suggested that a variety of patterns of cytokine production was present in the acute phase of this disease, and that the key cytokine, which might regulate the cytokine network, was IL-4.

Phenobarbital (PB) increases serum total cholesterol levels in rodents and humans. To investigate the underlying molecular mechanisms, we performed a microarray analysis on liver of rats treated repeatedly with 100 mg/kg PB, and examined the serum blood chemistry. The serum concentration of non-esterified fatty acids was decreased from day 1 to day 14 except for day 7, and that of cholesterol was increased from day 4 to day 14. The serum concentration of total ketone bodies was increased on day 7, and that of triglycerides was decreased on day 14. Transcript content of glycolytic genes was decreased by PB treatments, while that of lipoprotein lipase was continuously increased, suggesting a notion that repetitive PB treatments impaired glycolysis and stimulated lipolysis in the liver. The hypothesis was examined by using a previously reported flux-balance model. The increase in mRNA content of malic enzyme after the PB treatment agreed well with the flux-balance model result, suggesting the validity of our hypothesis. The findings also suggested that there was an abundance of acetyl-CoA and shortage of glycolytic products after the repeated PB treatments. Although ketogenesis would normally occur under such cellular conditions, it was only weakly observed after the repeated PB treatments, presumably owing to a decrease in HMG-CoA synthase mRNA content. On the other hand, the mRNA content of several cholesterogenic genes was slightly induced by PB treatments. Thus, serum chemistry and microarray results suggested that repeated PB treatments induced cholesterogenesis in rat livers, which may have contributed to the elevation of the serum total cholesterol concentration.

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Two rare cases of dissections which involve the anterior cerebral artery (ACA) are reported. A 58-yearold woman presented with a ruptured dissecting aneurysm manifesting as sudden onset of severe headache and consciousness disturbance followed by aphasia, right hemiparesis, paresis of the left lower extremity, and choreoathetotic movements of the upper arms and face. Computed tomography and angiography revealed subarachnoid hemorrhage due to a dissecting aneurysm at the left A 1 segment. The dissecting aneurysm was trapped surgically on the day of onset. Her neurological deficits disappeared within a month. A 39-year-old woman experienced continuous dull headache from the day before onset, and then suffered right hemiparesis. Magnetic resonance (MR) imaging revealed cerebral infarction at the left globus pallidus. Angiography and MR imaging revealed a dissecting aneurysm at the left A 1 segment and occlusion of the left Heubner's artery. She received conservative treatment and her neurological findings were improved. Dissections or dissecting aneurysms involving the ACA can be classified into three types: Extension of a dissection to the ACA from the internal carotid artery, dissection at the A 1 segment, and dissection at the A 2 -A 4 segments. These types of dissection have distinct uniform clinical features.