Studies on the mechanism of restraint-induced gastric ulcer--with special reference to mucosal ischemia and gastric secretion

Rat gastric mucosal blood flow, hydrochloric acid (HC1) secretion, and morphological changes of parietal cells were studied by light and electron microscopy using histochemical techniques. Mucosal blood flow of restrained rats was remarkably decreased compared with that of control rats, whereas the acetylcholinesterase activity, demonstrated by the method of Karnovsky and Roots, was significantly increased especially near the ulcer. In contrast, the differences in volume, acidity and acid output of gastric juice were not significant between control and restrained rats. Hypersecretion of HC1 induced by a parasympathetic stimulant, bethanechol, was inhibited by blood loss or infusion of cytochalasin B, an actin depolymerizing agent. 14C-aminopyrine accumulation in the primary cultured parietal cells was decreased by the treatment with hypoxia and cytochalasin B. These treatments also prevented the increase of 14C-aminopyrine accumulation induced by bethanechol. Actin filaments were evident in the cytoplasm of the parietal cells, particularly around the intracellular canaliculi and beneath the plasma membrane using the FITC-labeled phalloidin reaction and transmission electron microscopic observations of uranyl acetate block stained preparations following heavy meromyosin decorations. Ultrastructural studies of the parietal cells in restrained rats revealed that intracellular canaliculi were dilated with loss of microvilli. Actin filaments were noted to be disassembled, and granular with focal aggregation of actin filaments. Hypoxic vacuoles were also found in the cytoplasm. Treatments with blood loss and cytochalasin B infusion in the in vivo model, and hypoxia and cytochalasin B in the in vitro model, resulted in the similar changes. These observations indicate that actin filaments in the parietal cells of restrained rats may be depolymerized by ischemia. As the result, HC1 secretion would not be enhanced even if the parasympathetic nerves are excessively stimulated in the gastric mucosa. Thus, disturbances of the gastric mucosal microcirculation are considered to be important in the pathogenesis of the stress-induced gastric ulcer.     

Clinical investigation of perforated duodenal ulcer--with special reference to the presence of Helicobacter pylori infection and rate of recurrence]

Perforated duodenal ulcer was clinically evaluated with respect to Helicobacter pylori infection and rate of recurrence in 38 ulcer patients perforated and 154 patients with non-perforated duodenal ulcer who visited our hospital in past 5 years and 6 months. The frequency of occurrence of H. pylori-positivity was 42.1% in patients with perforated duodenal ulcer, significantly lower than that of 92.9% in patients with non-perforated lesions. This result suggests that H. pylori is hardly involved in the development of perforated duodenal ulcer. The rate of recurrence was significantly lower for perforated duodenal ulcer than for non-perforated ulcer. In particular, perforated duodenal ulcer did not recur in the group on maintenance therapy with H2-recepter antagonists. Maintenance therapy using inhibitors of gastric acid secretion seems effective for the prevention of recurrence of perforated duodenal ulcer.     

Secular trends in cardiovascular mortality in Iran, with special reference to Isfahan

OBJECTIVE: There has been a general decline in mortality from cardiovascular diseases (CVDs) in most of the developed countries since the beginning of the 1970s. Still, in recent years developing countries have seen an increasing frequency in CVD mortality. However, mortality rate studies in these populations are scarce. Here we report all-cause and CVD mortality rates for men and women aged 25-74 years over a 16-year period in 24 cities in Iran with special reference to the city of Isfahan. METHODS AND RESULTS: The study was based on national death records using the ninth international classification of diseases and age standardization was performed using the total population of Iran in 1985 as a standard. Due to limitations in available data, mortality rates for the specific categories of CVD for the whole country could not be provided. The in-hospital death rates following myocardial infarction in coronary care units (CCUs) and cardiology departments in Isfahan hospitals were also assessed. The completed medical records from hospitals or the relatives of decedents were reviewed by physicians certified in internal medicine, cardiology and neurology to assess the reliability of death certificate data regarding CVD by determining the sensitivity and specificity of the death certificates against the standard of the reviewers. The official circulatory diseases proportional mortality ratio continues to rise since 1981 with a steep increase since 1987, constituting 26.6% and 47.3% of all deaths in 1981 and 1995, respectively. Age-adjusted all-cause and CVD mortality data were decreasing since 1981 and increasing since 1990. During those years age-adjusted CVD, stroke and other CVD mortality rates were decreasing in Isfahan with a slight increase in ischaemic heart disease (IHD) death rates in both sexes. Mortality rates based on sex showed a 38% and 24.8% decline in all-cause and CVD mortality in men between 1981 to 1995, and a 35% and 34.9% decline for female mortality rates for the same period, respectively. The in-hospital death rate following myocardial infarction in Isfahan was increasing between 1993 and 1995 with a slight decrease thereafter. The results of death certification assessment showed a specificity of 0.89 and a sensitivity of 0.43 with the positive and negative predictive values of 0.82 and 0.57, respectively. CONCLUSION: These data indicate that circulatory diseases remain a serious public health threat in Iran. It suggests the ongoing need for more regular, systematic and innovative surveillance data to improve the capability of measuring, explaining and predicting the disease trend on which the national public health policy depends.