Abnormal distribution of cathepsins in the brain of patients with Alzheimer's disease

Formalin-fixed paraffin-embedded hippocampal sections of brains with early-onset and late-onset Alzheimer's disease were studied immunohistochemically with antisera against cathepsin D and cathepsin B. In addition to the staining of neuronal perikarya, some of the senile plaques visualized by Bielshowsky silver staining and some of reactive astrocytes were positively stained with the antisera against cathepsin D and cathepsin B in brains with Alzheimer's disease. Abnormal localization of cathepsin D and cathepsin B immunoreactivity in neuronal perikarya was observed in brains with early-onset Alzheimer's disease. These findings demonstrate that the distribution of lysosomal proteases was altered in brains with Alzheimer's disease, suggesting the primary and/or secondary involvement of the lysosomal proteases in the pathological process of Alzheimer's disease.     

Role of prostaglandin E receptor subtypes in gastroduodenal HCO3- secretion

Gastroduodenal HCO3- secretion is a key process that aids in preventing acid-peptic injury. Endogenous prostaglandins (PGs) play a particularly important role in the local control of this secretion. The secretion of HCO3- in both the stomach and duodenum was increased in response to PGE2 as well as mucosal acidification, the latter occurring with concomitant enhancement of mucosal PG generation. These HCO3- responses in the duodenum were markedly reduced by prior administration of the EP4 antagonist in rats, and profoundly decreased in the animals lacking EP3 receptors but not EP1 receptors. In contrast, gastric HCO3- responses induced by PGE2 and mucosal acidification were prevented by the EP1 antagonist and disappeared in EP1, but not EP3-knockout mice. Consistent with these findings, duodenal HCO3- secretion was stimulated by both EP3 and EP4 agonists but not EP1 or EP2 agonists, while gastric HCO3- secretion was increased by the EP1 agonist but not EP2, EP3 or EP4 agonists. In addition, the HCO3- stimulatory action of sulprostone (EP1/EP3 agonist) in the stomach was inhibited by the Ca2+ antagonist verapamil but not affected by IBMX, the inhibitor of phosphodiesterase, while that in the duodenum was inhibited by verapamil and enhanced by IBMX. Forskolin, the stimulator of adenylate cyclase, increased HCO3- secretion in the duodenum but not the stomach. Thus, the HCO3- stimulatory action of PGE2 in the duodenum is mediated by both EP3 and EP4 receptors being coupled intracellularly with both Ca2+ and cAMP, while that in the stomach is mediated by EP1 receptors, coupled with Ca2+.     

Natural antibodies against the immunoglobulin F(ab′)2 fragment cause elimination of antigens recognized by the F(ab′)2 from the circulation

A humanized monoclonal IgG1 antibody, designated hC4G1, recognizes the fibrinogen receptor glycoprotein (GP)IIb/IIIa on platelets and inhibits platelet aggregation. When the F(ab′)₂ fragment of hC4G1 (F(ab′)₂ hC4G1) was administered to cynomolgus monkeys, all the monkeys showed inhibition of platelet aggregation ex vivo. Unexpectedly, a significant decrease in platelet count was observed in 5 of 18 monkeys. Antibodies against F(ab′)₂ hC4G1 were detected in the plasma of these monkeys by ELISA. Antibody activity in the plasma of these monkeys was significantly correlated with the intensity of platelet decrease (r = 0.84). The natural monkey antibodies to F(ab′)₂ hC4G1 were directed against the C-terminal region of F(ab′)₂ fragment common to all human and humanized IgG antibodies. Natural homo-reactive antibodies were also detected in human plasma from 15 of 40 healthy volunteers. Specificity was closely similar to that of the monkey antibodies. Affinity-purified human homo-reactive antibodies enhanced phagocytosis of platelets treated with the F(ab′)₂ hC4G1. Monkey plasma with high homo-reactive antibody activity was confirmed to decrease platelet count when administered together with F(ab′)₂ hC4G1 to a monkey with low antibody activity. These results suggest that F(ab′)₂ of humanized and human antibodies causes elimination of the corresponding antigens from the circulation by homo-reactive antibodies.     

Copper and iron-induced oxidative damage in non-tumor bearing LEC rats

The copper and Iron status in the liver of non-tumor bearing Long-Evans Cinnamon (LEC) rats (average age 17 months) was investigated. A direct quantitation of loosely-bound copper and iron was also investigated by using a chelating agent, nitrilotriacetic acid (NTA-chelatable free copper and iron). Besides the total copper and iron contents, the level of NTA-chelatable free copper was also higher in LEC rats than In LEA rats (P<0.05). But for the free iron level there was no signiflcant difference between the two rat groups (P>0.05). The formation of thiobarbituric acid-reactive substances was higher In LEC rats than In LEA rats (P<0.01). The 4–hydroxy-2–nonenal (HNE)-modified proteins were also clearly demonstrated in LEC rat liver. The copper and iron which produced the most important effect In the process of oxidative damage in LEC rats could not be distinguished. Even though free copper, which could induce free radical injuries, was increased in LEC rats, neither tumor-induction nor preneo-plastic lesions in the experimental LEC rats were observed. Therefore it is speculated that the elevation of a free iron is another important factor. Copper and iron, both important translation metals In the body, may participate In the Induction of DNA damage and oncogenesls     

High prevalence of haemosiderin accumulation in the cytoplasm of gastric glands in patients with liver cirrhosis

AIMS: To investigate the presence of iron in biopsy and resection specimens from the stomach of patients with hepatic cirrhosis of various aetiologies. METHODS: Among 753 patients who had been admitted to the hospital with liver cirrhosis from 1984 to 2002, and 723 patients who underwent liver biopsy or liver resection from 1990 to 2003, 426 patients with concomitant gastric biopsy or gastrectomy were selected for study. Formalin fixed, paraffin wax embedded tissues of the stomach and the liver (when available) were retrieved from the pathology files of Kariya General Hospital, Japan. Haematoxylin and eosin staining and Perls' stain were performed for all the available tissues and haemosiderin and its localisation were examined. RESULTS: In total, 78 patients-72 of those with cirrhosis (26%) and six without cirrhosis (4%)-showed accumulation of haemosiderin. Regardless of aetiology, patients with clinical varices showed more frequent haemosiderin accumulation (40%) than patients without varices (19%). For patients with cirrhosis, there were no significant differences in the positive rate between those with (28%) or without (23%) hepatocellular carcinoma. CONCLUSION: The significant increase in haemosiderin deposition in the gastric glands of patients with cirrhosis suggests that the assessment of iron deposition in gastric biopsy specimens may have predictive value in controlling patients with cirrhosis.     

DNA analysis by polymerase chain reaction]

Polymerase chain reaction (PCR) is a technique to amplify only a specific segment of DNA without using a plasmid or a phage vector. It is a powerful tool for genetic analysis of various diseases including inherited and viral diseases, and is now being applied to clinical diagnosis. Here, presented are several methods using PCR mainly for diagnosis of hemoglobinopathy which we have been engaged in. Some other diseases are also included.     

Dandy-Walker variant in Coffin-Siris syndrome

We describe a five-month-old male infant with Coffin-Siris syndrome, the so-called Dandy-Walker variant (hypoplasia of the cerebellar vermis with cystic dilatation of the fourth ventricle, but without enlargement of the posterior fossa), and partial agenesis of the corpus callosum. Dandy-Walker malformation and mega cisterna magna, but not Dandy-Walker variant, have been reported in Coffin-Siris syndrome. The presence of Dandy-Walker variant in the infant we described confirms that the full continuum of the Dandy-Walker complex can occur in Coffin-Siris syndrome. The yet unidentified gene(s) for the syndrome may be related to the development of the hindbrain.