Ecabet sodium, a novel locally-acting anti-ulcer agent, protects the integrity of the gastric mucosal gel layer from pepsin-induced disruption in the rat.

BACKGROUND: Ecabet sodium, a novel non-systemic anti-ulcer agent, possesses high affinity to gastric adherent mucus, which plays an important role in the protection of the gastric epithelium against acid and pepsin. AIM: To assess the effect of ecabet on pepsin-induced degradation of the structure of the mucus gel layer. METHODS: Everted sacs of rat stomach were incubated in HCl solution containing pepsin with or without ecabet. Pepsin-induced release of the cleaved peptides and hexosamine from the sacs was determined. Changes in the molecular size of glycoproteins in the adherent mucus (using gel filtration methods) and in the morphology of the epithelium (using both light and scanning electron microscopy) were also examined. RESULTS: Ecabet reduced the pepsin-induced release of peptides and hexosamine, depending on its content in the adherent mucus. Pepsin treatment partially lowered the molecular weight of native glycoproteins in the adherent mucus, caused exfoliation of the epithelial cells, and degraded the network-like ultrastructure of the mucus layer, giving it a lumpy, globular appearance. Ecabet prevented both the pepsin-induced molecular size shift in mucus glycoproteins, and morphological alteration of the epithelium, including ultrastructural derangement of the mucus gel layer. CONCLUSION: Ecabet protects the polymeric structure of mucus glycoproteins from proteolytic degradation by pepsin, and thus maintains integrity of the gastric mucus gel layer.

Ultrastructure of spontaneous glomerular lesions in syrian hamsters of APA strain.

Electron microscopic observations were carried out on the spontaneous glomerular lesions in male APA hamsters from 3 to 12 months of age. Until 6 months of age, focal expansion of mesangial region due to an increase of matrix material and mesangial cells was characteristic, and segmental thickening of capillary basement membrane and partial effacement of foot processes of podocytes were also sometimes observed. At 12 months of age, although all of these changes became more severe, the most prominent alteration was found in podocytes, which showed various degenerative changes. No deposition of amyloid fibrils was detected in any portion of the glomerulus.

Dorsal skin responses to subchronic ultraviolet B (UVB)-irradiation in Wistar-derived hypotrichotic WBN/ILA-Ht rats.

Dorsal skin responses to a subchronic UVB-irradiation (10kJ/m2/rat /day), were examined in Wistar-derived hypotrichotic WBN/ILA-Ht rats for up to 3 months. Hyperplasia of epidermal cells and hair follicle epithelial cells as well as parakeratosis developed at 1 month and progressed thereafter, resulting in a prominent epidermis thickening and formation of epidermal ingrowths projecting into the dermis. At the same time, the percentage of proliferating cell nuclear antigen (PCNA)-positive epidermal cells significantly increased after I month. In some portions of the hyperplastic epidermis, especially of the epidermal ingrowths, keratinocytes were somewhat pleomorphic and migrated into the dermis. In the upper dermis, edema with capillary congestion, mast cell infiltration and fibroblast proliferation developed at I month, and the intensity of edema and the number of dermal mast cells was most prominent at 3 months. Edema spread to the epidermis, resulting in intercellular edema and subsequent dissociation of epidermal cells. Degeneration of collagen fibers was also detected in the upper dermis, especially beneath the epidermis. In addition, although not significant because of a large individual difference, the serum IgE concentration, showed a tendency to increase after 2 months. The present study clarified the characteristics of the dorsal skin responses to a subchronic UVB-irradiation in rats.

Rapid induction of atherosclerosis in rabbits.

Japanese white rabbits fed a restricted amount (100 g/head/day) of an atherogenic diet (AD) containing 0.2% cholesterol and 6% peanut oil showed mild and persistent hypercholesterolemia (338 +/- 79 mg/dl). They developed atherosclerotic lesions 4 weeks after deendothelialization of aorta carried out at the 4th week of AD-feeding. This rabbit model of atherosclerosis has such advantages as being able to be produced in a short period and having similar biochemical and pathological characteristics with those in human atherosclerosis.

Age-related changes in the dorsal skin histology in Mini and Wistar rats.

Mini rats (Jcl: WistarTGN(ARGHGEN)1Nts (MRs) are Wistar rat (WR)-derived transgenic rats in which the expression of growth hormone (GH) gene is suppressed by the presence of antisense transgene. The plasma GH level of MRs is reduced to 40 to 60% of that of WRs. In this study, to evaluate the influence of GH deficiency on the skin nature, age-related changes in the dorsal skin histology were compared between male MRs and WRs. Although there were no essential differences in the skin structures between the two strains, MRs had thinner skin with less collagens, more abundant subcutaneous adipose tissues and small-sized sebaceous glands compared with WRs. On the other hand, the hair cycle evaluated by the morphology and the depth of hair follicles was greatly different between them. Namely, two cycles of 4 weeks each were observed in both strains during the first 8 weeks after birth, but the cycle entered a long-lasting quiescence (telogen phase) in MRs while the 3rd cycle started in WRs afterwards. The lower level of serum insulin-like growth factor (IGF)-1 in MRs may be related to such a difference in hair cycle pattern, although the levels of IGF-1 and IGF-1 receptor mRNAs in the dorsal skin tissues were similar between MRs and WRs. MRs are considered to be a useful animal model for dermatopathy in patients suffering from GH deficiency and for grasping a clue to elucidate the exact effects of GH on the skin nature, especially on hair follicle development.

Sunburn reaction in the dorsal skin of hypotrichotic WBN/ILA-Ht rats.

The dorsal skin responses to a single irradiation with a high-dose of UVB (10kJ/m2) were examined histologically and immunohistochemically in UVB-sensitive Wistar-derived hypotrichotic WBN/ILA-Ht rats (HtRs). Sunburn cells (SBCs) which were characterized by pyknotic nuclei and eosinophilic cytoplasm and had ultrastructual characteristics of apoptotic cells were first observed in the epidermis at 3 hours (h) after irradiation. The number peaked at 6 h, and then decreased rapidly. The expressions of p53 protein, which is known to be closely related to the formation of SBCs, and of p21 protein, which is one of the transcriptional target genes of p53, were immunohistochemically detected, and their labeling index (LI) in the epidermis peaked at 12 to 24 h (p53) or at 24h (p21) after irradiation. On the other hand, proliferating cell nuclear antigen (PCNA)-LI in keratinocytes was significantly lower than the control group at 6 h after irradiation and thereafter it increased and became significantly higher than the control group from 24 to 48 h. At 48 h, moderate hyperplasia with moderate numbers of mitotic keratinocytes was first observed in the epidermis. In the dermis, mild edema developed from 12 to 36 h and it accompanied mild lymphocyte infiltration at 36 h. Judging from the present results, it was suggested that some factors other than p53 might be involved in SBC formation, and that p53 might induce p21 protein and play an important role in cell growth arrest in keratinocytes after UVB irradiation.

Hydrogen peroxide-induced dermatitis in WBN/Kob-Ht rats.

Light and electron microscopic examinations were carried out on the dorsal skin to which hydrogen peroxide (HPO) (3, 6, and 10%) was topically applied for 7 consecutive days in Wistar rat-derived inbred WBN/Kob-Ht rats which have an autosomal dominant gene responsible for their characteristics of hypotrichosis. In addition to focal epidermal thickening, keratinocyte necrosis, dermal mononuclear cell infiltration and focal detachment of the epidermis from the dermis by fluid-filled spaces were detected. This is thought to be brought about by edema due to prominent capillary endothelial damage in the superficial dermis. The damage to keratinocytes and capillary endothelial cells was thought to be induced by HPO itself and free radicals generated by HPO. In addition, these changes were apparently more severe in WBN/Kob-Ht rats than in Wistar rats used as controls.

Morphologic changes in hepatocyte nuclei of streptozotocin (SZ)-induced diabetic mice.

Morphological examinations were carried out on hepatocyte nuclei of streptozotocin (SZ)-induced diabetic mice. The area of hepatocyte nuclei in diabetic mice was about two times larger than that in control mice, and the incidence of hepatocytes with intranuclear inclusions was 3.4 +/- 0.2% in diabetic mice and 0% in control mice, respectively. Although the incidence of binuclear hepatocytes was not significantly different between diabetic (14.5 +/- 4.6%) and control mice (16.4 +/- 4.4%), the morphology of the nuclei of binuclear hepatocytes was apparently different between diabetic and control mice. Namely, the nuclei of binuclear hepatocytes of control mice were round and identical in ultrastructural appearance, and they did not differ from those of mononuclear diploid hepatocytes. On the other hand, the nuclei of binuclear hepatocytes of diabetic mice were not identical in distribution pattern of chromatin granules, and they frequently varied in size and showed irregular contours.

Comparison of atherogenicity of soybean oil and peanut oil, and effect of clentiazem on diet-induced atherosclerosis in rabbits.

Rabbits were fed with two kinds of atherogenic diet, one containing 0.5% cholesterol and 3% soybean oil and the other 0.5% cholesterol and 6% peanut oil, for three months to compare the atherogenic property of the diets. The soybean oil diet seemed to be superior to the peanut oil diet for evaluation of the anti-atherogenic effect of drugs, because the former caused milder vascular lesions than the latter. Using this rabbit model for atherosclerosis, the anti-atherogenic effect of clentiazem, a new calcium antagonist, was examined. Clentiazem at an oral dose of 30 mg/kg/day significantly reduced the size of atheromatous lesion in the aortic arch and thoracic aorta, and lowered the collagen content of the aortic intima and media, although it did not decrease serum lipid levels. On the other hand, clentiazem showed no clear effect on reducing the coronary atherosclerotic lesions. These results suggest that clentiazem may inhibit the progression of diet-induced aortic atherosclerosis without normalizing the serum lipid levels.

GM2-gangliosidosis variant 0 (Sandhoff-like disease) in a family of Japanese domestic cats.

A five-month-old, female Japanese domestic shorthair cat with proportionate dwarfism developed neurological disorders, including ataxia, decreased postural responses and generalised body and head tremors, at between two and five months of age. Leucocytosis due to lymphocytosis with abnormal cytoplasmic vacuolations was observed. The concentration of G(M2)-ganglioside in its cerebrospinal fluid was markedly higher than in normal cats, and the activities of beta-hexosaminidases A and B in its leucocytes were markedly reduced. On the basis of these biochemical data, the cat was diagnosed antemortem with G(M2)-gangliosidosis variant 0 (Sandhoff-like disease). The neurological signs became more severe and the cat died at 10 months of age. Histopathologically, neurons throughout the central nervous system were distended, and an ultrastructural study revealed membranous cytoplasmic bodies in these distended neurons. The compound which accumulated in the brain was identified as G(M2)-ganglioside, confirming G(M2)-gangliosidosis. A family study revealed that there were probable heterozygous carriers in which the activities of leucocyte beta-hexosaminidases A and B were less than half the normal value. The Sandhoff-like disease observed in this family of Japanese domestic cats is the first occurrence reported in Japan.

Bactericidal effect of ecabet sodium on clarithromycin- and metronidazole-resistant clinical isolates of Helicobacter pylori.

Ecabet sodium showed a bactericidal effect on Helicobacter pylori NCTC 11637 which is susceptible to antimicrobial agents (Antimicrob. Agents Chemother, 39: 1295-1299, 1995). In the present study, we investigated the bactericidal effect of ecabet sodium on clarithromycin- and metronidazole-resistant strains of clinical isolates of H. pylori under acidic conditions. In a buffer supplemented with urea at pH 3.0, ecabet sodium decreased the number of viable cells in both isolates. In the morphological study, ecabet sodium changed the isolates from the bacilliform to the horseshoe-shaped form and denatured the cytoplasm. Ecabet sodium also showed the bactericidal effect on both isolates in buffers at pH 4.0 and 5.0, and the bactericidal effect was dependent on pH, i.e., the lower the pH, the greater the effect. These results suggest that the susceptibility of H. pylori to antimicrobial agents does not affect the bactericidal effect of ecabet sodium on H. pylori.

Thymic granulomatous lesions in pigs.

Rare cases of thymic granulomatous lesions were found in pigs. The lesions consisted of epithelioid cells, multinucleated giant cells, and lymphocytes. Such lesions also were observed in the mesenteric lymph nodes, spleen, kidney, and stomach. The cytoplasm of the majority of giant cells and some epithlioid cells was periodic acid-Schiff (PAS) positive. All cells were positive for vimentin, lysozyme, and desmin. Ultrastructurally, the giant cells were rich in organella and attached to adjacent epithelioid cells by membrane interdigitation. The cells included numerous coated vesicles and granules. No etiologic pathogen, including porcine circovirus type 2, was detected in the lesions. This is the rare case of idiopathic thymic granulomatous lesion in pigs.

Two cases of feline malignant craniopharyngioma.

Tumors at the cranial base in 2 cats (a 9 1/2-year-old, castrated male Chinchilla and a 7-year-old, castrated male American Shorthair) were diagnosed as malignant craniopharyngioma. The tumor lesion was histopathologically divided into four parts: 1) a small acinus part, in which relatively large cells with a pale cytoplasm composed small acini; 2) a duct part, in which small cuboidal cells composed ducts; 3) a cyst part, in which there were large cysts lined with flat cells; and 4) a pavement part, in which large multi-angular-shaped cells proliferated in a pavement pattern. The epithelial cells of some parts were positive for keratin by immunohistochemistry. Histopathologic findings of the present feline cases were identical to those of malignant craniopharyngioma in other animal species.

Rapid warming of infusion solution.

A useful method was developed to warm solutions rapidly used for infusion and peritoneal irrigation, frozen plasma and blood for transfusion. It takes only two minutes to warm 1 liter of saline solution from a room temperature (24.5 degrees C.) to a body temperature (37.0 degrees C.) with the 600 w electronic range. The time necessary to warm a solution to any temperature can be simply determined. With an infrared sensor, the time setting is not necessary. A large volume of a solution can be rapidly warmed. The time necessary to warm any solution can be shortened with higher wattage. Whole blood did not suffer any change from the rapid warming. A living fish was also not damaged by the electronic range, which directly vibrates and heats water molecules with high frequency electromagnetic waves. With the present method, troublesome warming procedures which have been done in many hospitals, even at midnight, are not necessary anymore.

Cancer pain treatment with a simple custom-built portable waterproof microautoinjector.

Severe cancer pain was relieved by a simple custom-built microautoinjector. Its injecting power is derived from the decomposition and expansion of medical-grade 3.3% hydrogen peroxide. The injection speed is controlled by the addition of a microamount of medical-grade iodide which catalyzes the hydrogen peroxide. The amount of potassium iodide used is so small that decomposition and expansion speeds are nearly constant. The size of the power device is 1 cm3; it may be inserted into the injector, which then does not need a gasket any more. This means that this microinjector with the solution to be injected is only half the size of an ordinary disposable syringe. It is convenient for epidural anesthesia of untreatable cancer pain.

Effects of ecabet sodium (TA-2711), a new antiulcer agent, on gastrointestinal mucosal prostanoid production and morphology in rats.

Effects of ecabet sodium (TA-2711), a locally acting antiulcer agent, on prostanoid production and the morphology of the rat gastrointestinal mucosa were studied in comparison with sucralfate. Ecabet, at therapeutic doses (25 and 100 mg/kg, p.o.), dose-dependently increased the gastric mucosal level of prostaglandin E2 (PGE2): sucralfate (100 mg/kg, p.o.) showed a tendency to increase the PGE2 level. In an ex vivo study, ecabet (25 and 100 mg/kg, p.o.) dose-dependently increased the capacity of the gastric mucosa to synthesize PGE2 and PGI2 without modifying tromboxane A2 (TXA2) synthesis, and the 100 mg/kg dose persisted for up to 3 h. Ecabet (400 mg/kg, p.o.) also significantly increased PGE2 synthesis and there was a tendency to increase PGI2 synthesis by the duodenal mucosa, without affecting TXA2 synthesis. PGE2 synthesis by the colonic mucosa was not affected, even at a high dose of ecabet (1000 mg/kg, p.o.). When the rat gastric mucosa was examined by light microscopy and scanning electron microscopy, ecabet (100 and 400 mg/kg, p.o.) had caused no morphological change to the gastric mucosa, while sucralfate (100 and 400 mg/kg, p.o.) produced apical rupture of the epithelial cells and subepithelial edema. The present study indicates that ecabet locally stimulates PGE2 and PGI2 production in the gastroduodenal mucosa and this effect is not attributable to a local irritant action accompanied by superficial epithelium damage.

Fine structure of epithelial cells of Lieberkühn's crypts in feline panleukopenia.

Electron microscopic observation was carried out on epithelial cells of Lieberkühn's crypts of cats naturally affected with feline panleukopenia. The most important change was the replication of feline panleukopenia. The most important change was the replication of feline panleukopenia virus in the nucleus with associated alterations in the lining epithelial cells of the crypts. In these cells in the early stage of infection, virus particles 20 nm in average diameter were found either singly or in small regularly arrayed clusters everywhere in the markedly swollen nucleus. In the course of infection, the nucleus of infected cells became rather atrophic with a marked margination of chromatin granules. Its major portion was occupied with masses of fine fibrillar substance. It was a "viral matrix area" in which appeared a large compact aggregate of virus particles showing a crystalline array. At the same time, the outer membrane of the nuclear envelope partially extended and disrupted. Membranous elements related to it in the cytoplasm were regularly distributed almost always with particles indistinguishable from the virus particles in the nucleus. From these results it was suggested that the major portion of the infected nucleus, or the site of viral replication, might correspond to the amphophilic intranuclear inclusion body revealed by light microscopy.

Isolation and properties of sialodacryoadenitis virus of rats.

Pathogenic agents were isolated from affected salivary glands of rats with sialodacryoadenitis (SDA) by means of intercerebral inoculation to newborn mice and inoculation to primary rat kidney cell cultures. The properties of these isolates, irrespective of the isolation techniques, were in general agreement with that of SDA virus strain 681, and they were identified as SDA virus. In addition to the known properties, following characteristics were noticed: (1) Particles of SDA virus bore two different long and short surface projections. (2) Some antigenic differences were observed between the present isolate 930-10 and the strain 681. (3) It was suggested that SDA virus grew better at 35 degrees C than at 31 degrees, 33 degrees, 37 degrees or 39 degrees C. (4) SDA virus did not propagate in DBT cells.

Pathological observations on natural cases of sialodacryoadenitis of rats.

Pathological observations were carried out on 100 male rats of Sprague-Dawley strain obtained from 5 outbreaks of sialodacryoadenitis (SDA). In accordance with clinical and macroscopic findings, principal microscopic changes were found in the salivary (submaxillary and parotid) and Harderian glands. Lesions observed in these different glands were essentially similar to each other, and characterized by degenerative changes in the epithelial cells of the ducts and acini associated with marked and extensive serous inflammation in the interstice. Furthermore, squamous metaplasia of the ductal epithelia was a common feature to these glands in the late stage of the disease. Some differences, however, were detected between the changes of the salivary glands and those of the Harderian glands. Firstly, the ductal epithelial cells were affected at first and the acinous epithelial cells were damaged only secondarily in the active inflammatory process in the salivary glands, while both ductal and acinous epithelial cells were involved equally in the primary lesion in the Harderian glands. Secondly, the increase in connective tissue elements in the reparatory process was extremely marked in the Harderian glands as compared with the salivary glands. Consequently, in the lesion of Harderian glands in the late stage, original construction was almost indiscernible, and the ducts and acini were only recognized as disseminated islets in actively proliferated connective tissue elements.

Pathology of chemically induced chronic active hepatitis in mice.

Female Swiss mice were treated for 24 weeks, with 3-hydroxy-4-pyrone (Py) added to their powdered diet at 0.5% (wt/wt), and the effects of this agent on the liver were examined. Serum transaminases (especially GPT) rose continuously, while the GOT/GPT ratio remained at approximately 1.0 throughout the study period. The characteristic changes found from 8 weeks onward were piecemeal necrosis and bridging necrosis of the hepatocytes with dense lymphocytic infiltration. Proliferation of collagen fibers in the portal tracts and formation of narrow fibrous septa dividing the lobules into pseudolobules were also noted from 12 weeks onward. A large number of the infiltrating lymphocytes were identified as T cells by immunohistochemical and electron microscopic studies. These lymphocytes often surrounded or were closely attached to degenerating hepatocytes. Focal apoptosis and necrosis accompanied by a granulomatous reaction of the centrilobular hepatocytes were noted as early changes in the liver. Our findings indicate that the hepatic changes produced in mice by long-term Py administration have characteristics in common with those of human chronic active hepatitis. Immunological cytotoxic mechanisms, especially T cell-mediated ones, appear to play an essential role in the development of hepatic lesions in this murine model of chronic active hepatitis.