Effects of rebamipide, a novel anti-ulcer agent, on gastric mucosal injury induced by platelet-activating factor in rats.

We examined the role of gastric mucosal blood flow, lipid peroxidation, and neutrophil accumulation mediated by platelet-activating factor in the protective effect of rebamipide against gastric mucosal injury in rats. The intravenous injection of platelet-activating factor induced hyperemia and hemorrhagic erosions in rat stomachs. Rebamipide did not affect the decrease in the gastric mucosal blood flow induced by platelet-activating factor. The increase in gastric injury score after platelet-activating factor injection and the increase in thiobarbituric acid-reactive substances were significantly inhibited by the administration of rebamipide. The gastric injury score was closely correlated with the accumulation of lipid peroxides. Tissue-associated myeloperoxidase activity in the gastric mucosa significantly increased after platelet activating factor injection; this increase was not influenced by rebamipide treatment. The protective effect of rebamipide against the platelet-activiting factor-induced gastric mucosal injury may be due to direct inhibition of lipid peroxidation or scavenging of oxygen radicals that initiate lipid peroxidation.

Role of active oxygen, lipid peroxidation, and antioxidants in the pathogenesis of gastric mucosal injury induced by indomethacin in rats.

The roles of active oxygen, lipid peroxidation, and the antioxidative defence mechanism in gastric mucosal injury induced by treatment with indomethacin in rats were investigated. The total area of gastric erosions and concentration of lipid peroxides in the gastric mucosa increased with time after administration of indomethacin (20 mg/kg, orally). The alpha-tocopherol:total cholesterol ratio in serum was significantly decreased and the activity of glutathione peroxidase, an important enzyme to scavenger of lipid peroxides, was inhibited by the administration of indomethacin. Treatments with superoxide dismutase and catalase inhibited the increases in gastric mucosal erosions and lipid peroxides in the gastric mucosa, and the reduction of serum alpha-tocopherol. Treatment with these scavengers did not improve the decreased glutathione peroxidase activity. These findings suggest that active oxygen species and lipid peroxidation play an important part in the pathogenesis of gastric mucosal injury induced by indomethacin, and that the decreased glutathione peroxidase activity aggravated the injury due to accelerated accumulation of hydrogen peroxide and lipid peroxides in the gastric mucosal cell.

[Tetralogy of Fallot revealed by autopsy in an elderly subject].

A 62-year-old women had a history of cyanosis and easy fatigability from school age but had refused medical examinations. She was admitted to our department with exacerbation of dyspnea at the age of 59. Laboratory tests showed hypoxia complicated with polycythemia with 35 mmHg of PaO2, 8.5 x 10(6) erythrocytes per mm3. The systolic pressure of the right ventricle was 155 mmHg. RI angio demonstrated a high degree of the right-to-left shunt at the ventricular level. The patient was given oxygen therapy at home without diagnosis of tetralogy of Fallot (TOF) and eventually died at the age of 62. Tetralogy of Fallot was diagnosed at autopsy. Pulmonary stenosis of this case was located in infundibulum. The lining of the infundibular inlet was constituted of the thick fibrous tissue which remarkably augmented the pulmonic stenosis. Although the autopsy findings were considered to be relatively mild TOF, the death was presumed to be caused by development of the infundibular stenosis due to formation of fibrous tissue. This is the oldest patient in Japanese medical literature to be identified by cardiac catheterization and autopsy finding as a case of TOF.

[Role of oxygen-derived free radicals for antitumor effects of intra-arterial injection with adriamycin].

This study examined the role of oxygen-derived free radicals for antitumor effects of intra-arterial injection with adriamycin (ADR). The effect of chemoembolization using ADR and degradable starch microspheres (DSM) was studied in rabbits with VX2 carcinoma of the hind leg. The tumor growth in rabbit treated with chemoembolization (ADR: 3.0 mg/kg + DSM 20mg/kg) was completely suppressed, but the therapeutic effect of chemoembolization combined with dimethylsulfoxide (DMSO) was reduced. On the other hand, the therapeutic effect of chemoembolization combined with superoxide dismutase and catalase was not reduced. These results indicate that the production of oxygen-derived free radicals, especially hydroxyl radical in the cancer cell, plays an important role in the antitumor effect of adriamycin.

Two cases of pancreatic cystadenocarcinoma with elevated CA 19-9 levels in the cystic fluid in comparison with two cases of pancreatic cystadenoma.

A 39-year-old woman was hospitalized with left hypochondralgia. Ultrasonography and abdominal computed tomography showed a cystic mass in the tail of the pancreas. Echo-guided aspiration of the cyst was performed, and a markedly elevated CA 19-9 level in the cystic fluid was found. A surgical operation was performed, and the tumor was radically resected. The pathologic diagnosis was papillary adenocarcinoma of the pancreas. Another case of pancreatic cystadenocarcinoma also had an extremely high cystic CA 19-9 level, whereas two cases with benign pancreatic cysts had very low cystic CA 19-9 levels. Moreover, positive localization of CA 19-9 in the cancerous tissue was clearly demonstrated by an immunohistochemical technique, indicating active secretion of CA 19-9 into the cyst, while CA 19-9 in the tissue of pancreatic cystadenoma was almost non-existent. Measurement of the CA 19-9 level in the cystic fluid might therefore be a valuable additional aid in the diagnosis of cystadenocarcinoma of the pancreas.

[Two cases of spontaneous pneumomediastinum in healthy young men].

We report two cases of spontaneous pneumomediastinum. Both were young males, and had no causal diseases or apparent precipitating episodes. Both recovered rapidly with bed rest only. Symptoms, signs, radiological diagnosis, and pathogenesis of pneumomediastinum are discussed.