Akio Komatsu

NORMAL PRESSURE HYDROCEPHALUS

The pathological changes in the brains of seven patients who had been clinically diagnosed as normal pressure hydrocephalus (NPH) are described and the possible etiological mechanisms are discussed. The pathological findings in all cases consisted of demyelination akin to Binswangers type of encephalopathy, especially in the frontal lobes. Arteriosclerosis accompanied by occasional organized thrombi and scattered microinfarcts in the periventricular white matter were seen. Focal leptomeningeal fibrosis, diminution of arachnoidal granulations, and non‐specific aging processes were noted. Among the above of particular interest, was the degeneration of both periventricular and deep white matters with microinfarcts, and moderate to severe arteriosclerosis. On the basis of these observations, we assume that the degeneration in the white matter is not merely a secondary change due to the result of enlargement of ventricle, but plays an important role in the development of NPH. The development of NPH requires not only the disturbance of cerebrospinal fluid, but also the pre‐or coexisting vulnerability in the white matter caused by variables such as ischemia, hypoxia, and trauma.

Experimental infection of germ-free mice with hyper-toxigenic enterohaemorrhagic Escherichia coli O157:H7, strain 6.

A mouse enterohaemorrhagic Escherichia coli (EHEC) infection model was developed with a combination of germ-free (GF) mice and hyper-toxigenic EHEC (HT-EHEC) O157:H7 strain 6. The HT-EHEC strain 6 produced both Shiga-like toxin (SLT)-1 1.0 microg/mI and SLT-2 8.2 microg/ml in vitro. Eight-week-old germ-free mice were inoculated intragastrically with 5.0 x 10(7) cfu of HT-EHEC strain 6. All GF mice challenged with the HT-EHEC developed ruffled fur and convulsion of limbs or hindleg weakness within 3 days after the challenge, culminating in death within 5 days. The HT-EHEC colonised well at a level of 10(8) - 10(9) cfu/g of faeces 5 days after the challenge. Both SLT-1 and SLT-2 were demonstrated in the faeces of the mice for 5 days after challenge. Histological examination of the colons of the infected mice showed congestion of the lamina propria mucosa, mild inflammatory cell infiltration and goblet cell depletion. In proximal tubules of the renal cortex, epithelial swelling with scattered necrotic cells was recognised. Endothelial swelling and mononuclear cell infiltration were also observed in the glomeruli. The brain showed acute neuronal necrosis in the cerebrum and slight loss of Purkinje cells in the cerebellum. Passive immunisation with anti-SLT antisera prolonged the life of the mice without anyneural symptoms. Microscopically, all tissue specimens from the passively immunised mice were not remarkable. These results indicate that the infection of GF mice with HT-EHEC is a useful animal model to study the pathogenicity of SLT-producing E. coliand the toxins.

Effect of Bacterial Flora on Postimmunization Gastritis following Oral Vaccination of Mice with Helicobacter pylori Heat Shock Protein 60

ABSTRACT In order to assess the efficacy of oral Helicobacter pylori heat shock protein 60 (HSP60) as a vaccine, protection against H. pylori infection in specific-pathogen-free (SPF) C57BL/6 and germfree (GF) IQI mice was examined. Prophylactic oral vaccination of these two strains of mice with either H. pylori HSP60 or Escherichia coli GroEL inhibited H. pylori colonization by 90 to 95% at 3 weeks postinfection (p.i.). However, these mice were only partially protected because bacterial loads increased in all animals at 10 weeks p.i. Anti-H. pylori HSP60 immunoglobulin G was detected in serum at 3 weeks p.i. in mice vaccinated with either H. pylori HSP60 or GroEL. Significant increases in the gastritis scores were observed only in SPF mice immunized with H. pylori HSP60. These results indicate that oral vaccination with H. pylori HSP60 has partial protective effects on subsequent H. pylori infection but also induces postimmunization gastritis. However, GF mice immunized with H. pylori HSP60 did not suffer from severe gastritis. Therefore, the presence of bacterial flora appears to contribute to the induction of postimmunization gastritis.

A study of the development of atherosclerosis in childhood and young adults: Risk factors and the prevention of progression in Japan and the USA

Coronary heart disease (CHD), one of the prevalent results of atherosclerotic disease, has been a leading cause of death in many Western countries for several decades, and now is the second most prevalent cause of death in Japan. Thus attention must also be paid to atherosclerosis in Japan. While there has been a remarkable reduction in the mortality rate from CHD in some Western Countries, an undesirable stabilized mortality rate has recently been reported by the government of Japan. This report emphasises the importance of preventing atherosclerosis at an early stage from the viewpoint of cardiovascular pathology, using evidence from statistical data derived from autopsied cases in Japan and the USA.

Angiosarcoma-like metastatic carcinoma of the liver

Two cases of metastatic carcinoma strikingly simulating angiosarcoma in the liver are described. The first case was a 53-year-old female with cystic liver tumors which were found 22 months after surgery for ureteral cancer. The second case was an 81-year-old female with multiple tumors in the liver and the pancreas, and a post-mortem examination was carried out. She had undergone surgery for skin cancer three years before. Both cases had an angiosarcoma-like appearance macroscopically and microscopically. Immunohistochemically, the tumor cells of both cases were negative for CD31, CD34, and Factor VIII-related antigen and positive for several types of cytokeratin, suggesting that they were not angiosarcomas but carcinomas. Angiosarcoma is the most common sarcoma arising in the liver. Thus, metastatic carcinoma, which resembles angiosarcoma, might be mistaken for angiosarcoma.