First record of non-native hybrid catfish Pseudoplatystoma reticulatum × Leiarius marmoratus in the Upper Paraná River basin, Brazil.

The aim of this study is to report the presence of a three non-native hybrid long-whiskered catfishes (family Pimelodidae) in the Upper Paraná River basin, Brazil. Genetic analyses demonstrated that the three presumptive hybrids were a result of the crossbreeding of Pseudoplatystoma reticulatum (central Amazonas River basin and Lower Paraná River) and Leiarius marmoratus (Amazonas, Essequibo and Orinoco rivers), producing a hybrid commonly known in Brazil as cachandiá. The potential threat to biodiversity, due to possible genetic contamination, competition and predation of wild stocks, of such artificially produced hybrid fishes is discussed.

Activation of the beta-catenin gene by interstitial deletions involving exon 3 as an early event in colorectal tumorigenesis.

beta-Catenin has been identified as an oncogene in several tumors including colorectal cancers. beta-Catenin gene is activated by interstitial deletions involving exon 3 in colorectal carcinomas of Japanese population, in contrast to amino acid substitutions detected among Caucasian population. The aim of this study was to examine the type and frequency of beta-catenin gene mutation during early stages of colorectal tumorigenesis. We screened 100 colorectal adenomas for somatic mutations in the beta-catenin gene by single-strand conformation polymorphism method, as well as polymerase chain reaction amplification. In cases with mutations, sequencing analyses and immunohistochemical staining were also performed. Somatic interstitial deletions of 272-413 bp, each of which included all parts of exon 3, were detected in three tumors. However, no adenoma carried missense mutations. We confirmed accumulation of aberrant beta-catenin protein in cytoplasm and nuclei of adenoma cells by immunohistochemical analysis. Our results suggested that activation of the beta-catenin gene by interstitial deletions involving exon 3 might be less frequent compared with frequent alterations of adenomatous polyposis coli (APC) gene, but could be an early event in colorectal tumorigenesis equivalent to APC gene alterations in the Japanese population.

Secondary aortoduodenal fistula complicating aortic grafting, as a cause of intermittent chronic intestinal bleeding.

Intermittent intestinal bleeding persisted in a 77-year-old male, who had undergone grafting for abdominal aortic aneurysm. Each attack lasted for a few weeks and spontaneously resolved. Only a minute abnormality was found in the third portion of the duodenum; barium studies showed a segmental narrowing, but endoscopy disclosed only a small erosion in that portion. Massive and fatal gastrointestinal hemorrhage broke out 6 months after the onset of bleeding. Autopsy revealed an adhesion area with a small fistula formation between the duodenum and aorta. Even slight endoscopic findings should be considered suggestive of aortoenteric fistula in patients after aortic surgery.

Mucosal interleukin-1 beta production and acid secretion in enlarged fold gastritis.

BACKGROUND: We have previously shown that eradication of Helicobacter pylori increases acid secretion in H. pylori-associated enlarged fold gastritis. AIM: To investigate whether locally produced interleukin-1 beta is possibly involved in the inhibition of acid secretion in H. pylori gastritis. METHODS: IL-1 beta release from the gastric body mucosa was determined by short-term culture of biopsy specimens in 13 patients with enlarged fold gastritis (all H. pylori-positive), five H. pylori-positive and 10 H. pylori-negative patients without enlarged folds. The acid-inhibitory effect of locally produced IL-1 beta was examined by [14C]-aminopyrine uptake assay using isolated rabbit gastric glands. RESULTS: IL-1 beta release was significantly greater in patients with enlarged fold gastritis, significantly correlated with both basal and tetragastrin-stimulated acid outputs in the H. pylori-positive patients (r = -0.591 and r = -0.641, respectively; P < 0.01), and significantly decreased with concomitant increases in acid secretions after eradication of H. pylori. [14C]-aminopyrine uptake was inhibited by IL-1 beta in a dose-dependent manner. CONCLUSIONS: Increased production of IL-1 beta caused by H. pylori infection is possibly involved in the inhibition of acid secretion in enlarged fold gastritis.

Follow-up after the Hanshin-Awaji earthquake: diverse influences on pneumonia, bronchial asthma, peptic ulcer and diabetes mellitus.

We evaluated the influence of the Hanshin-Awaji earthquake on the patients in our internal medicine department. After the initial rush of patients with injury, the number of respiratory diseases, largely pneumonia, increased within one month. This same event, however, seemed to decrease attacks among asthma patients. During the following three months, the number of peptic ulcer patients increased: 39.5% had a giant gastric ulcer and 34.8% had bleeding complications. Diabetic control of outpatients became worse after the earthquake. It is important to recognize that various disorders involving physical and psychological problems develop at different stages after a large-scale disaster.

Increased production of interleukin 1 beta and hepatocyte growth factor may contribute to foveolar hyperplasia in enlarged fold gastritis.

BACKGROUND AND AIMS: It has been reported that eradication of Helicobacter pylori improves fold width in H pylori associated enlarged fold gastritis. The aim of this study was to clarify the mechanism of fold thickening in this condition. PATIENTS AND METHODS: In eight patients with enlarged fold gastritis and 13 patients without enlarged folds, the presence of H pylori infection, inflammatory infiltrates, mucosal plasia, and epithelial cell proliferation in the body mucosa were investigated, and production of transforming growth factor alpha (TGF alpha), hepatocyte growth factor (HGF), and interleukin 1 beta (IL 1 beta) was determined by a competitive reverse transcription/polymerase chain reaction method and in vitro short-term culture of biopsy specimens. RESULTS: In the patients with enlarged fold gastritis, inflammatory infiltrates including macrophages increased with H pylori colonisation in the body. Foveolar thickness and proliferating cell nuclear antigen (PCNA) labelling index were increased. Messenger RNA levels of HGF, but not TGF alpha, were increased, and release of HGF and IL 1 beta was increased. HGF release, which was positively correlated with IL 1 beta release and foveolar thickness, decreased in the presence of IL 1 receptor antagonist. After eradication of H pylori, inflammatory infiltrates, IL 1 beta and HGF release decreased with concomitant decreases in PCNA labelling index, foveolar thickness and fold width. CONCLUSIONS: Increased IL 1 beta and HGF production caused by H pylori infection may contribute to fold thickening of the stomach by stimulating epithelial cell proliferation and foveolar hyperplasia in patients with enlarged fold gastritis.

Localization of heparin-binding epidermal growth factor-like growth factor in human gastric mucosa.

BACKGROUND & AIMS: Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has been recently identified as a member of the EGF family. EGF receptors to which HB-EGF can bind have been detected in some types of gastric epithelial cells. The aim of this study was to investigate whether HB-EGF is produced in gastric epithelial cells to maintain normal gastric mucosa. METHODS: Gene expression and production of HB-EGF protein were investigated using Northern hybridization and immunohistochemistry, and the types of cells producing this protein were determined in human gastric mucosa. RESULTS: HB-EGF messenger RNA was detected in the body and antrum. Immunohistochemical staining showed that HB-EGF was localized mainly in parietal cells of fundic glands and in gastrin cells of pyloric glands. Also, the immunoreactivity of EGF receptors was observed in parietal cells and gastrin cells and faintly in surface epithelial cells and mucous neck cells of the proliferative zone. CONCLUSIONS: The results suggest that HB-EGF is synthesized mainly in parietal cells and gastrin cells and may act in an autocrine and/or paracrine manner in the regulation of proliferation and differentiation of the gastric mucosal cells through their surface EGF receptors.

Inhibition of gastrin-stimulated enterochromaffin-like cell proliferation and mucosal histamine production in the rat stomach by the somatostatin analogue octreotide.

The effect of octreotide, a potent and long-acting analogue of somatostatin, on gastrin-stimulated proliferation and function of enterochromaffin-like (ECL) cells were examined in rats. Animals were divided into four groups and each group was continuously infused with saline, octreotide alone (40 micrograms/kg per day), gastrin alone (60 nmol/kg per day), or octreotide (40 micrograms/kg per day) plus gastrin (60 nmol/kg per day) respectively for 9 days via osmotic minipumps. Gastrin induced the increase of the bromodeoxyuridine labeling index and density of oxyntic mucosal ECL cells as well as oxyntic mucosal histidine decarboxylase activity. Octreotide completely abolished the gastrin-induced increases in the labeling index and density of ECL cells and oxyntic mucosal histidine decarboxylase activity. These results indicate that octreotide inhibits gastrin-stimulated proliferation of ECL cells and histamine production by these cells.

Improved fold width and increased acid secretion after eradication of the organism in Helicobacter pylori associated enlarged fold gastritis.

This study examined the effects of eradication of Helicobacter pylori (H pylori) infection on gastric mucosal morphology and acid secretion. Sixteen H pylori positive patients with enlarged gastric body folds were divided into two groups: (a) patients with moderate enlargement (fold width: 6 to 10 mm, n = 8) and (b) patients with severe enlargement (> 10 mm, n = 8). After successful treatment, gastric body fold width was reduced in both groups (p < 0.01) with an associated decrease in inflammatory infiltrates in the body mucosa (p < 0.01 and p < 0.05). Basal acid output and tetragastrin stimulated maximal acid output (mean (SEM)) in all 16 patients significantly increased from 1.1 (0.5) to 2.9 (0.9) mmol/h (p < 0.05) and from 5.4 (1.3) to 18.7 (2.3) mmol/h (p < 0.01), respectively, with a significant decrease in fasting serum gastrin concentrations, from 127.1 (16.1) to 59.6 (3.8) pg/ml (p < 0.01). The increase in acid secretion after eradication of H pylori was more noticeable in the severe group, who had shown lower acid secretion and higher serum gastrin concentrations (p < 0.05) before eradication, than the increase seen in the moderate group. The decreases in ammonia nitrogen content seen after eradication were significant in basal (from 0.91 (0.17) to 0.37 (0.08) mmol/h, p < 0.05) and stimulated gastric secretions (from 1.57 (0.19) to 0.37 (0.13) mmol/h, p < 0.01), although these changes were too small to explain the increases in basal acid output and maximal acid output. These results suggest that inflammation of the gastric body mucosa caused by H pylori infection is associated with enlarged gastric body folds and inhibition of acid secretion in H pylori positive patients with enlarged gastric body folds.

Immunohistochemical localization of basic fibroblast growth factor in the healing stage of mouse gastric ulcer.

The aim of this study was to clarify the involvement of basic fibroblast growth factor (bFGF) in gastric ulcer healing. For this purpose, light and electron microscopic immunohistochemical studies for bFGF were performed using an experimental gastric ulcer model of mice. Ulceration was induced by the application of acetic anhydride to the serosal surface of the body of the stomach. Stomach tissues were investigated of mice at 5 days and 3 weeks respectively after treatment and also of untreated normal mice. Five days after treatment an ulcer was seen in the stomach of the experimental mice. Immunohistochemistry revealed that bFGF was localized in fibroblasts in the ulcer bed. The growth factor was distributed throughout the cytoplasm excluding organelles involved in the usual secretory system, such as rough endoplasmic reticulum, Golgi apparatus and secretory vacuoles. bFGF was also detected in the nucleus. Three weeks after treatment the surface of the ulcer lesion was completely covered by regenerated epithelium. The stomach tissues were immunohistochemically negative for bFGF both inside and outside the scar region; untreated normal stomach tissues were also negative for bFGF. These results suggest that the growth factor plays important roles in gastric ulcer healing.

Immunohistochemical, autoradiographic and electron microscopic studies on the transformation of fibroblasts into chondrocytes in the mouse subfascia induced by bone morphogenetic protein.

Functional morphology on the transformation of fibroblasts into chondrocytes induced by bone morphogenetic protein (BMP) was studied by light and electron microscopy using 35S autoradiography and immunohistochemistry for S-100 protein and type-II collagen. A pellet containing BMP obtained from a murine osteosarcoma was transplanted into the mouse subfascia. By 3 days after implantation, many typical fibroblasts, which were free of the silver grains for 35S and devoid of both S-100 protein and type-II collagen, entered the pellet region. By 5 days, the fibroblasts in the pellet region became polygonal in shape, and cytoplasmic vesicles and vacuoles appeared, both containing a homogeneous substance of low electron density. At 5 days, autoradiography revealed many silver grains for 35S over the Golgi apparatus and vesicles and vacuoles of the cells in the pellet region as well as over the surrounding extracellular matrix. Moreover, the cells at 5 days displayed immunoreactivity to both proteins. The extracellular matrix around the cell began to show clear metachromasia and increased in amount with time. At 9 days all the cells in the pellet region were round or oval in shape and surrounded by an abundant cartilaginous matrix. The rough endoplasmic reticulum and Golgi apparatus were extremely well developed, and a large number of vacuoles and vesicles were seen in the cytoplasm. These cells showed intense immunoreactivity to both proteins, and strong accumulation of sulfur was visualized in the extracellular matrix by autoradiography. These results suggest that the fibroblasts in the pellet region change into chondroblasts by 5 days, and become typical chondrocytes by 9 days.

Ultramicroscopic aspects of the conversion of fibroblasts to chondrocytes in the mouse dorsal subfascia induced by bone morphogenetic protein (BMP).

Direct conversion of typical fibroblasts to chondrocytes in the mouse fibrous connective tissue induced by bone morphogenetic protein (BMP) was observed by light as well as electron microscopy. A pellet containing BMP obtained from a murine osteosarcoma was transplanted into the dorsal subfascia of 5 week-old mice. Until 3 days after implantation of BMP, all the connective tissue cells in the pellet region of the dorsal subfascia showed the fine structural features of typical fibroblasts. The cells in the pellet region changed their shape from spindle-like to polygonal by 5 days after implantation. At this time, small vacuoles 150-450 nm and vesicles 40-60 nm in diameter, containing a homogeneous substance of low electron density, appeared in the cytoplasm of the cells. A small amount of extracellular substance, showing metachromasia by toluidine blue staining, was seen around the cells. Moreover, autoradiography of 35S revealed the uptake of sulfur by the cells and its accumulation in the extracellular substance around the cells in the pellet region at 5 days. The rough endoplasmic reticulum and Golgi apparatus increasingly developed with time and after 7 days both elements were distributed throughout the cytoplasm. The cytoplasmic small vacuoles and vesicles also increased in number with time, and the metachromatic extracellular substance containing fine filamentous meshwork and many tiny particles, which was regarded as the matrix of cartilage, also increased rapidly in amount. By 9 days, the cells in the pellet region became oval or round in shape, showing many short cytoplasmic processes.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of the gene transcripts of 11 beta-hydroxylase and aldosterone synthase in the rat adrenal cortex by in situ hybridization.

Using in situ hybridization, localization of the gene transcripts of 11 beta-hydroxylase and aldosterone synthase was investigated in order to clarify the sites for the synthesis of corticosterone (glucocorticoid) and aldosterone (mineralocorticoid) in the rat adrenal cortex. The gene transcript of 11 beta-hydroxylase was localized in all the endocrine cells of the entire adrenal cortex, while that of aldosterone synthase was exclusively confined in zona glomerulosa cells. These results represent that every endocrine cell of all the cortical zones synthesizes 11 beta-hydroxylase which converts 11-deoxycorticosterone to corticosterone, and only glomerulosa cells synthesize aldosterone synthase which produces aldosterone from corticosterone. Thus it is clearly shown that zona glomerulosa cells synthesize mineralocorticoid, while zona fasciculata as well as reticularis cells produce glucocorticoid.