Evidence for early blood-brain barrier breakdown in experimental thiamine deficiency in the mouse

In order to assess the involvement of blood-brain barrier (BBB) breakdown in the pathogenesis of thiamine deficiency encephalopathy, autologous albumin immunohistochemistry was performed in mice which were rendered thiamine-deficient by pyrithiamine, a BBB-permeant antagonist of thiamine. In the presymptomatic animals until day 8 of the treatment, histological lesions were not detected by H&E staining. However, localized staining of albumin was evident, suggesting an extravascular leakage of the endogenous intravascular protein. On day 10 of thiamine deficiency, when neurological signs appeared, both histological lesions and massive albumin extravasation were demonstrated in all the animals. The BBB breakdown was only occasionally observed in the brains of mice treated with oxythiamine, a BBB-impermeant antagonist or in control animals. These results suggest that BBB breakdown is not only a phenomenon secondary to tissue destruction, but it is more directly involved in the pathogenesis of thiamine deficiency encephalopathy.     

Microtubules mediate mitochondrial distribution in fission yeast.

The Schizosaccharomyces pombe mutant, ban5-4, displays aberrant mitochondrial distribution. Incubation of this conditional-lethal mutant at the nonpermissive temperature led to aggregated mitochondria that were distributed asymmetrically within the cell. Development of this mitochondrial asymmetry but not mitochondrial aggregation required progression through the cell division cycle. Genetic analysis revealed that ban5-4 is an allele of atb2 encoding alpha 2-tubulin. Consistent with this finding, cells with the cold-sensitive nda3 mutation in beta-tubulin displayed aggregated and asymmetrically distributed mitochondria after incubation at lowered temperatures. These results indicate that microtubules mediate mitochondrial distribution in fission yeast and provide the first genetic evidence for the role of microtubules in mitochondrial movement.     

A functional RNAi screen for Runx2-regulated genes associated with ectopic bone formation in human spinal ligaments

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic ossification in the spinal ligaments, which enlarges with time and compresses the spinal cord, resulting in serious neurological symptoms. We previously reported that Runx2 expression was enhanced in spinal ligament cells from OPLL patients (OPLL cells). To clarify genes regulated by Runx2, Runx2 expression was first enhanced by culturing primary OPLL cells in osteogenic medium (OS induction) and then inhibited by siRNAs targeted to Runx2. DNA microarray demonstrated that in addition to chondrogenic factors such as connective tissue growth factor and cartilage oligomeric matrix protein, angiopoietin-1 was also significantly increased by OS induction and decreased by siRNAs for Runx2 in OPLL cells, suggesting that these genes are regulated by Runx2. However, these changes were not observed in non-OPLL control cells (from cervical spondylotic myelopathy patients). Furthermore, Runx2 was not decreased by siRNAs for angiopoietin-1. OS induction and RNAi inhibition of angiopoietin-1 expression was also observed in osteoblasts. Both siRNAs for Runx2 and angiopoietin-1 completely inhibited aggrecan-1 expression. These results suggest that angiopoietin-1 is downstream of Runx2 in both OPLL primary cells and osteoblasts. Angiopoietin-1 may play an important role in ectopic ossification.     

Isolation and characterization of the measles virus strains with low hemagglutination activity.

Six measles virus strains were isolated from clinical specimens. They differed from a prototype strain in being incapable to grow in cell lines derived from monkey kidney and having a slower electrophoretic mobility of the hemagglutinin protein and a very low hemagglutination activity.     

Class 1 integron containing metallo-beta-lactamase gene blaVIM-2 in Pseudomonas aeruginosa clinical strains isolated in Japan

Four bla(VIM-2) gene-harboring Pseudomonas aeruginosa strains were identified. These strains possessed a class 1 integron harboring ORF1, bla(VIM-2), and aacA4 gene cassettes. The transposon-mediated horizontal spread of the bla(VIM-2) gene among these strains was suggested, which increases the threat that the bla(VIM-2) gene will disseminate among diverse genera of bacteria.     

A patient in whom only hepatitis B virus (HBV) was thought to have been contracted, by kissing, from a same-sex partner coinfected with HBV and human immunodeficiency virus-1

A 31-year-old homosexual man was admitted to our hospital in August 2001 with liver dysfunction. His diagnosis was acute hepatitis B. He had had a steady partner coinfected with hepatitis B virus (HBV) and human immunodeficiency virus-1 (HIV) from August 2000 to July 2001. Because he knew that the partner was infected with HIV, the sexual relationship had included only deep kissing, with no oral-genital or anal-genital sex. The serum HBV DNA level of the partner was relatively high compared with the serum HIV RNA level. Direct sequencing of the full HBV DNA genome from serum showed that the entire base sequences of the viruses from both patients were of genotype A and identical. HBV infectivity was shown to be stronger than that of HIV in our patient, in whom only HBV was transmitted from a partner coinfected with HBV and HIV. This case highlights the importance of HBV as a sexually transmitted disease.     

Factors correlating with acoustic radiation force impulse elastography in chronic hepatitis C

AIM: To investigate the factors other than fibrosis stage correlating with acoustic radiation force impulse(ARFI) elastograpy in chronic hepatitis C. METHODS: ARFI elastograpy was performed in 108 consecutive patients with chronic hepatitis C who underwent a liver biopsy. The proportion of fibrosis area in the biopsy specimens was measured by computerassisted morphometric image analysis. RESULTS: ARFI correlated significantly with fibrosis stage(β = 0.1865, P < 0.0001) and hyaluronic acid levels(β = 0.0008, P = 0.0039) in all patients by multiple regression analysis. Fibrosis area correlated significantly with ARFI by Spearman’s rank correlation test but not by multiple regression analysis. ARFI correlated significantly with body mass index(BMI)(β =-0.0334, P = 0.0001) in F 0 or F 1, with γ-glutamyltranspeptidase levels(β = 0.0048, P = 0.0012) in F 2, and with fibrosis stage(β = 0.2921, P = 0.0044) and hyaluronic acid levels(β = 0.0012, P = 0.0025) in F 3 or F 4. The ARFI cutoff value was 1.28 m/s for F ≥ 2, 1.44 m/s for F ≥ 3, and 1.73 m/s for F 4. CONCLUSION: ARFI correlated with fibrosis stage and hyaluronic acid but not with inflammation. ARFI was affected by BMI, γ-glutamyltranspeptidase, and hyaluronic acid in each fibrosis stage.