Sulfhydryl blocker-induced colitis in the rat: immunological changes in thymus gland and colonic mucosa

The study was designed to examine the changes of thymus in sulfhydryl blocker-induced colitis. We used N-ethylmaleimide (NEM) as sulfhydryl blockers. Fasted male Sprague-Dawley rats were given 3% NEM in 1% methyl cellulose into the colon. N-ethylmaleimide treatment caused severe diarrhoea with bleeding for the first 7 days. At autopsy, adhesions, colon dilatation, and single or multiple erosions and ulcers were observed. Time-course studies revealed that the lesions were most extensive and severe 3 or 7 days after the administration of NEM. Histological examination of colon on the 3rd day after NEM treatment demonstrated mucosal erosion, oedema and extensive infiltration of neutrophils. The mucosal lesions extended into the submucosa and muscle on the 7th day after NEM treatment. Immunohistochemical studies showed that T cells and macrophages were markedly increased in the lamina propria of colonic mucosa. After 3 weeks, the infiltration of chronic inflammatory cells was observed and regeneration of the mucosa was noticed. The thymus gland was significantly decreased in weight and size on the 3rd day after NEM treatment, but the weight loss of thymus gland was regained in 3 weeks. Transient atrophy of thymus gland was noticed in this colitis model. The phenotypes of thymocytes were not influenced by NEM treatment. It is concluded that the thymus abnormalities in human ulcerative colitis are not induced in this animal model and that other chronic models are necessary for the elucidation of the immunological abnormalities, including thymus abnormalities.

[Application of the Limulus test for practical quality control on endotoxin content in commercial human serum albumin (HSA) products. In comparison with the rabbit pyrogen test]

The bacterial endotoxin content in human serum albumin (HSA) products measured by two different Limulus amebocyte lysate (LAL) test methods, colorimetric and kinetic turbidimetric methods, were compared. So far as endotoxin-specific LAL reagents which do not show a false-positive reaction with (1-->3)-beta-D-glucan are used, a definite correlation was found between the results with the two LAL test methods. Endotoxin added to HSA products was recovered in a quantitative manner showing neither inhibition nor enhancement by HSA to the both LAL test methods. Results of the LAL tests showed a significant correlation with that of the rabbit pyrogen test. The correlation was much improved with endotoxin-added HSA. The present results indicate the practical applicability of the LAL test as an alternative method for the rabbit pyrogen test.

Inhibition of Helicobacter pylori urease activity by hydroxamic acid derivatives

Helicobacter pylori (HP) produces strong urease [EC 3.5.1.5], which is considered to play a role in the pathogenesis of gastritis and peptic ulcers. Inhibitions against this enzyme have been studied with hydroxamic acid (HXA) derivatives of aliphatic or aromatic carboxylic acids, amino acids and dipeptides. A number of HXAs potently inhibited the urease (I50 values were near the order of 10(-6)M), and H-Ile-Gly-NHOH (I50 = 0.20 x 10(-6)M) was the most potent inhibitor among the derivatives. HP urease was inhibited more potently, in general, than Jack bean (JB) urease by HXAs, and a correlation between the chemical structures of HXA derivatives and their inhibitory effects on HP urease was observed, in comparison with JB urease.

Rebamipide, a novel antiulcer agent, attenuates Helicobacter pylori induced gastric mucosal cell injury associated with neutrophil derived oxidants

The effect of rebamipide, a novel antiulcer compound, on Helicobacter pylori activated neutrophil dependent in vitro gastric epithelial cell injury was investigated. Luminol dependent chemiluminescence (ChL), which detects toxic oxidants from neutrophils exhibited a 12-fold increase when the bacterial suspension of H pylori was added to the isolated human neutrophils. This change was significantly attenuated by rebamipide at a concentration less than 1 mM, showing that rebamipide may inhibit oxidant production from H pylori elicited neutrophils. To assess whether rebamipide attenuates gastric mucosal injury, we tested its inhibitory action on H pylori induced gastric mucosal damage associated with neutrophils in vitro. Rabbit gastric mucosal cells were monolayered in culture wells and coincubated with human neutrophils and H pylori, and the cytotoxicity index was then calculated. Cultured gastric cells were significantly damaged when they were incubated with human neutrophils activated by H pylori. This cellular damage was attenuated by rebamipide in a dose-dependent manner. Furthermore, spectrophotometrical measurement showed that rebamipide (1 mM) inhibits urease activity by 21.7%. As monochloramine (an oxidant yielded by reaction of neutrophil derived chlorinated oxidant and ammonia) is proposed as an important toxic molecule in this model, the current findings suggest that the preventive effect of rebamipide on H pylori elicited neutrophil induced gastric mucosal injury may result from its inhibitory actions on the neutrophilic oxidative burst as well as H pylori derived urease activity.

Aza-tricyclic substance P antagonists

The synthesis and structure-activity relationships of a series of aza-tricyclic analogs of the quinuclidine substance P (SP) antagonist 1 are described. The SP receptor affinity of these compounds was found to vary according to the size of the new ring fused to the quinuclidine and the mode of fusion. Correlations between receptor affinity and (1) the steric bulk of the newly introduced ring fusion and (2) the dihedral angle between the benzhydryl and benzylamino substituents of these aza-tricyclic compounds were explored.

Target protein for eucaryotic arginine-specific ADP-ribosyltransferase

Among ADP-ribosyltransferases reported in eucaryotes, arginine-specific transferases from turkey erythrocytes, chicken heterophils and rabbit skeletal muscle have been purified and extensively studied. They were reported to modify a number of proteins in vitro. ADP-ribosylation of Ha-ras-p21 and transducin by the turkey erythrocyte transferase inhibits their GTPase and GTP-binding activities. Chicken heterophil enzyme modifies several substrate proteins for protein kinases and decreases the phosphate-acceptor activity. Rabbit skeletal muscle Ca(2+)-ATPase is inhibited by ADP-ribosylation catalyzed by the muscle transferase. Three transferases all ADP-ribosylate small molecular weight guanidino compounds such as arginine, arginine methylester and agmatine and poly-L-arginine and nuclear histones. However, the observation that muscle transferase did not ADP-ribosylate casein or actin, both of which can be modified by the heterophil transferase under the same conditions indicates that substrate specificity of these two enzymes are different. Substrate-dependent effects were observed with polyions of nucleotides such that polyanions stimulate the ADP-ribosylation of possible target protein, p33 by chicken heterophil transferase but has no effect on the modification of casein by the same enzyme.

Gene expression of interstitial collagenase (matrix metalloproteinase 1) in gastrointestinal tract cancers

Collagenolytic proteinases play an important pathological role in the invasion and metastasis of cancer cells. However, little is known about the role of interstitial collagenase (matrix metalloproteinase-1; MMP-1) in this process. To investigate the expression of the MMP-1 gene in cancer tissues, an in situ hybridization study was carried out in gastrointestinal tract cancers (one esophageal cancer, five gastric cancers, and four colorectal cancers), using a 35S-labeled MMP-1 cDNA probe. The MMP-1 gene was expressed in the stromal cells of fibrous tissue around cancer nests, especially at the margin of invasion and/or within the cancer nest; however, no definite expression within cancer cells was observed. Expression of the MMP-1 gene in the stromal cells was more common in well differentiated gastric adenocarcinoma than in poorly differentiated adenocarcinomas. These findings indicate that expression of the MMP-1 gene is greater in stromal cells that are closely associated with cancer cells, suggesting a pathophysiological role of MMP-1 in the invasion and metastasis of cancer cells.

A cephalometric and electromyographic study of upper airway structures in the upright and supine positions

Obstructive sleep apnea (OSA) is characterized by recurrent upper airway obstruction during sleep, usually in the supine position. To investigate the relationship between upper airway size and genioglossus (GG) muscle activity, upright and supine cephalograms were obtained in 20 OSA patients and 10 symptom-free control subjects. Tongue electromyographic (EMG) recordings were obtained with surface electrodes, and pressure transducers were placed in the 10 symptom-free controls. The tongue cross-sectional area increased 4.3% (p < 0.05), and the oropharyngeal area decreased 36.5% (p < 0.01) when the OSA patients changed their body position from upright to supine. No changes were observed in the tongue area, but soft palate thickness increased (p < 0.01) when the control subjects changed from the upright to the supine position. Furthermore, the oropharyngeal cross-sectional area decreased 28.8% (p < 0.01) despite a 34% increase (p < 0.05) in resting GG EMG activity. Posterior tongue pressure increased 17% (p < 0.05) with the change from upright to supine. On the basis of these findings, we propose that body posture has a substantial effect on upper airway structure and muscle activity. This postural effect should be taken into account when assessing upper airway size in the erect posture (conventional cephalography) and in the supine position (computed tomography). The vertical and anteroposterior position of the tongue and its relationship to airway size may be more important than soft palate size in the pathogenesis of OSA.

Verotoxin induces hemorrhagic lesions in rat small intestine. Temporal alteration of vasoactive substances

E. coli O157:H7 produces a cytotoxin active against Vero cells that has been termed verotoxin. In this study, we demonstrated that local intraarterial injection of verotoxin induced a decrease in blood flow and an increase in hemorrhagic lesions in rat small intestine. Significant increases in the area of hemorrhagic lesions were observed at 120 min after verotoxin injection. These lesions were produced by either verotoxin 1 or 2, but verotoxin 2 produced more extensive lesions. The temporal alteration of vasoactive substances in microcirculatory beds was determined after the administration of culture filtrate of E. coli O157:H7. Tissue-type plasminogen activator activity in regional plasma was significantly elevated as early as 30 min, suggesting that local fibrinolytic activation mediated by microvascular endothelium occurred. There was also early elevation of platelet-activating factor content in the ileal mucosa and its level remained significantly elevated thereafter. Intestinal blood flow, as determined by a laser Doppler flowmeter, started to decrease at about 45 min. The platelet-activating factor antagonist CV6209 was shown to attenuate the decrease in blood flow as well as the development of hemorrhagic lesions, demonstrating that platelet-activating factor is an important mediator for the microcirculatory damage. Accumulation of neutrophils demonstrated by myeloperoxidase activity in the intestinal mucosa and overproduction of oxygen-radicals from neutrophils of the mesenteric veins determined by the luminol-dependent chemiluminescence assay were observed at 60 min, corresponding with the decreased blood flow. Platelet-activating factor may be closely involved in the process of leukocyte accumulation and increased oxygen radical generation, because CV6209 also significantly attenuated these changes.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo visualization of lymphatic microvessels and lymphocyte migration through rat Peyer's patches

BACKGROUND/AIMS

In the small intestine, lymphocytes migrate through Peyer's patches. The distribution of lymphatic microvessels in rat Peyer's patches and lymphocyte traffic through them were studied.

METHODS

Vital dyes were injected via a micropipette into the Peyer's patches tissue to fill lymphatic microvessels and to stain lymphocytes in lymphatic microvessels.

RESULTS

Direct microscopic observation revealed a dense plexus of lymphatic microvessels in the perifollicular and interfollicular areas. Injection of the dyes into the germinal center failed to delineate lymphatic microvessels. The lymphatic microvessels in the perifollicular area were filled with lymphocytes. Most lymphocytes in the perifollicular lymphatics stayed in the lymphatic microvessels. Some lymphocytes became detached and drained into lymphatic microvessels in the interfollicular areas. Lymphocytes then moved toward the submucosal lymphatics beneath the villi around the Peyer's patches. The interfollicular lymphatics did not display contractile activity but had valves. Opening and closing of valves was synchronized with the respiration and the back and forth flow of lymphocytes.

CONCLUSIONS

There are numerous lymphocytes in a dense lymphatic network in the perifollicular and interfollicular areas of Peyer's patches. This well-developed lymphatic network has the potential capacity for storage of lymphocytes and modulation of lymphocyte migration.

Rat CINC/gro: a novel mediator for locomotive and secretagogue activation of neutrophils in vivo

The effects of rat CINC/gro, a member of the interleukin-8 family, on the endothelium-neutrophil interaction and transendothelial macromolecular leakage were studied in rat mesenteric microcirculation. Thirty minutes after superfusion with 10 nM CINC/gro, the number of neutrophils adherent to the venular endothelium and those migrated across the venules were significantly increased with a concomitant elevation of luminol-dependent chemiluminescence at the site of adhesion. Transendothelial macromolecular leakage as assessed by the relative length of venular wall stained with monastral blue B was also increased at 30 min after the start of CINC/gro superfusion. Pretreatments with a CD18-directed monoclonal antibody, WT-3 (1 mg/kg), significantly attenuated the increase in number of adherent and migrated neutrophils, the increase in luminol-dependent chemiluminescence, and the venular macromolecular leakage after the application of CINC/gro. These data suggest that CINC/gro is a novel stimulator that evokes not only locomotive but also secretagogue activation of neutrophils via a CD18-dependent mechanism in vivo.

Humanization of a mouse anti-human interleukin-6 receptor antibody comparing two methods for selecting human framework regions

Mouse monoclonal antibody AUK12-20 binds to human IL-6 receptor and inhibits IL-6 functions. It has been humanized by CDR-grafting for therapeutic use. In the design of reshaped human AUK12-20 VL region, the human framework regions (FRs) from the human Bence-Jones protein REI were used. The reshaped human AUK12-20 light chain, in combination with chimeric AUK12-20 heavy chain, bound to antigen as well as chimeric AUK12-20 antibody. In the design of reshaped human AUK12-20 VH region, two sets of the human FRs were chosen and compared. One set was from the consensus amino acid sequence for human VH regions subgroup (HSG)-I and the other set was from human antibody HAX, the most similar human VH region found in a database of human immunoglobulin sequences. The HSG-I-based and the HAX-based reshaped human AUK12-20 heavy chains in combination with the reshaped human AUK12-20 light chain, showed approximately 90 and 100% antigen-binding and competition-binding activities as compared to the chimeric or mouse AUK12-20 heavy chains. Most importantly, these humanized antibodies inhibited the IL-6-dependent tumor cell growth as well as the original mouse antibody suggesting that these humanized antibodies could be efficacious in human patients. Our results show that both approaches for the design of reshaped human antibodies can be used for successful humanization. The approach based on FRs from the most similar individual human antibody, however, seemed to be best for designing a reshaped human antibody that mimicked as closely as possible the original mouse antibody.

Alteration of mucosal immunity after long-term ingestion of an elemental diet in rats

The effects of an elemental diet on lymphocyte transport in intestinal lymph and immune responses of gut-associated lymphoid tissue were investigated in rats. The control animals were fed a conventional diet. After 4 week of feeding, the total calorie intake and body weight gain showed no differences between the two groups. The number and total area of Peyer's patches and the ratio of height of villi to height of crypt showed no significant differences between the two groups. The rate of lymph flow in intestinal lymphatics showed no significant change in treated animals compared with the control rats. However, an elemental diet induced a significant decrease in lymphocyte flux in intestinal lymphatics compared with that in control rats. Lymphocyte subsets in intestinal lymph revealed a significant decrease in CD3-positive cells, especially CD4-positive cells in the elemental diet-treated group. A significant decrease in the number of immunoglobulin A-containing cells and a decreased CD4/CD8 ratio in T-cell subsets were observed in the lamina propria of ileal mucosa in the elemental diet-treated group by morphometric analysis in the immunohistochemical study. Specific antibody-secreting cells in intestinal lymph were also investigated after rats were intraduodenally primed with cholera toxin and challenged with the same toxin after an interval of 2 weeks. No significant difference was seen between the two groups in any of the numbers of anti-cholera toxin immunoglobulin-secreting cells in any immunoglobulin A, immunoglobulin G, or immunoglobulin M class as determined by the enzyme-linked immunospot assay.(ABSTRACT TRUNCATED AT 250 WORDS)

The impact of diabetes mellitus on the prognosis of alcoholics

In this study, the mortality of clinically treated Japanese alcoholics with diabetes mellitus was analysed. Fifty-one diabetic alcoholics without liver cirrhosis (DM), 23 diabetic and cirrhotic alcoholics (DM.LC), 44 cirrhotic alcoholics without diabetes (LC), and 354 alcoholics without either complication (AL) admitted to the National Institute on Alcoholism in 1985 were studied. Thirty-seven diabetics required insulin treatment, and 12 oral hypoglycemic agents. The 4.4-year survival and drinking status after discharge were studied in 1990. Stepwise logistic regression analysis showed that the estimated odds for death increased 8.10, 4.38, 3.70, and 3.27 times for the subjects with the alcohol misuse after discharge, DM, DM.LC, and LC, respectively. The 4.4-year survival rate of alcoholics who continued misusing alcohol was much lower in DM (26%,P < 0.0005) and LC (35%, P < 0.0001) than in AL (73%). The survival rate of those who stopped misusing alcohol was significantly higher in DM (90%, P < 0.0001), LC (88%, P < 0.0001) and AL (94%, P < 0.0005) than those who continued misusing alcohol. There was no significant difference in the survival rate between the alcoholics with DM.LC who continued misusing alcohol (50%) and those who stopped misusing alcohol (73%). In the dead patients, 56% of DM died unexpectedly or suddenly, whereas 71% of LD died of liver failure after hospitalization. These results suggest that diabetic alcoholics should be intensively educated for abstinence.

Gastric mucosal injury: microcirculation and Helicobacter pylori

The integrity of gastric mucosa is well-balanced by an array of defensive mechanisms which protect the mucosa against external aggressive factors. When excessive stimulation of autonomic nervous system (irritation) is induced, microcirculatory disturbances easily lead to the gastric mucosal damage due to the formation of vasoactive mediators and oxygen radicals. In this review, our discussion has been focused on the co-ordinating function of the autonomic nervous system as well as the microcirculation as an important defense bastion. In this context, Helicobacter pylori represents an important pathogenic factor. In particular, we have discussed the contribution of monochloramine, and active oxidant, which is formed by neutrophils in the presence of ammonia derived from H. pylori to the gastric mucosal injury. Microcirculatory disturbances may be also involved in the pathogenesis of H. pylori-induced mucosal injury. On the basis of these considerations, we should not depend solely on the use of anti-acid secretory drugs for the treatment of gastric mucosal injury, but also should be aware of beneficial effect of mucosal protective drugs which may act on microcirculation and the autonomic nervous system.

In vivo effect of chronic administration of vasoactive intestinal peptide on gut-associated lymphoid tissues in rats

The in vivo effects of chronic administration of vasoactive intestinal peptides (VIP) on the lymphoid cell traffic and the population and function of cells in intestinal lymph and gut-associated lymphoid tissues were examined in rats. VIP was continuously infused from the superior mesenteric artery in rats at a dose of 10 ng/min/kg body weight for 96 h. Lymphocyte transport through intestinal lymph was significantly reduced by VIP without any changes in lymph flow. When lymphocyte subpopulation was examined in intestinal lymph, T cell subsets were decreased with a dominant reduction in the population of helper T cells. T cell subsets were also decreased in mesenteric lymph nodes, but in this case suppressor/cytotoxic T cell subsets were mainly reduced. Despite of the decrease in lymphocyte transport through intestinal lymph and changes of lymphocyte subpopulation, proliferative response of lymphocytes from intestinal lymph and mesenteric lymph nodes to phytohemagglutinin did not show any significant alteration after administration of VIP. By histochemical study on the lamina propria of the small intestine, the population of pan T cells, especially helper T cells, was demonstrated to be significantly decreased after VIP treatment. There was also a marked decrease in the number of immunoglobulin (Ig) A-containing cells in the lamina propria of the small intestine in VIP-treated rats, while no significant changes were seen in the number of IgG and IgM-containing cells. Our present results showed the possibility that a long-term alteration of serum VIP levels could affect the dynamics of immune effector cells and IgA production in gut-associated lymphoid tissues.

Vortex-mixing-induced inactivation of arginine-specific ADP-ribosyltransferase activity and re-activation of the less-active form by dithiothreitol plus NaCl under anaerobic conditions

We observed dilution/vortex-mixing-induced inactivation of arginine-specific ADP-ribosyltransferase purified from chicken peripheral polymorphonuclear granulocytes (heterophils) and re-activation of the less active form by dithiothreitol plus NaCl, under anaerobic conditions. The vortex-mixing-induced inactivation of the diluted enzyme was rapid; more than 85% of the enzyme activity was lost with 1-min vortex-mixing at room temperature. When the less-active form of the enzyme was treated with 10 mM dithiothreitol plus 0.2 M NaCl, under anaerobic conditions, more than 50% of the enzyme activity was restored. Putative mechanisms of the vortex-mixing-induced inactivation and dithiothreitol/NaCl-dependent re-activation of the arginine-specific ADP-ribosyltransferase are discussed.

Evidence of direct interaction between Kupffer cells and colon cancer cells: an ultrastructural study of the co-culture

A co-culture study of purified rat Kupffer cells and human colon cancer cells was performed, and the process of the tumor cell injury was observed under an inverted type fluorescence microscope loaded with propidium iodide, and also under an electron microscope. Ultrastructurally there was direct membrane-to-membrane interaction between Kupffer cells and colon cancer cells in time. The interaction occurred 1 h after start of the co-culture, and injured tumor cells were observed closely attached to pseudopodia of Kupffer cells at 6 h. The number of propidium iodide-positive tumor cells with damage increased in time. Pretreatment with NG-monomethyl-L-arginine reduced the number of injured tumor cells without preventing morphological interactions, but superoxide dismutase did not prevent the tumoricidal effect. Pretreatment with trypsin completely inhibited cell interaction and damage to tumor cells. In conclusion, the morphological interaction of Kupffer cells as a first step and the involvement of nitric oxide-derived free radicals as a second step seem to play a significant role in the host-defense mechanism.

Automodification of arginine-specific ADP-ribosyltransferase purified from chicken peripheral heterophils and alteration of the transferase activity

Auto-ADP-ribosylation of arginine-specific ADP-ribosyltransferase purified from chicken peripheral heterophils was investigated. When the purified ADP-ribosyltransferase was analyzed with sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by Coomassie brilliant blue staining, two protein bands corresponding to the molecular masses of 27.5 and 28.0 kDa were detected. Both proteins were auto-ADP-ribosylated when they were examined by zymographic in situ gel assay without exogenous acceptor for ADP-ribose transfer. The automodification was inhibited by the acceptor, arginine or agmatine, and an inhibitor of arginine-specific ADP-ribosyltransferase, novobiocin. The ADP-ribose-transferase linkage was labile in 0.5 M hydroxylamine (pH 7.5). The automodified transferase was not chased by a large excess of nonradioactive NAD and did not catalyze transfer of its ADP-ribose to p33, an endogenous substrate protein for the transferase in heterophils, therefore, that automodified transferase cannot serve as an intermediate in ADP-ribosylation of other proteins. Auto-ADP-ribosylated transferase showed higher activity than did the unmodified transferase in catalyzing ADP-ribosylation of the basic acceptor such as poly(L-arginine) and p33 while to ADP-ribosylate the acidic proteins such as casein, the modified transferase was less active. Automodification of the transferase decreased polyanion-induced ADP-ribosylation of p33. Automodification of arginine-specific ADP-ribosyltransferase apparently alters the specificity of its own substrate.

Attenuating effect of antithrombin III on the fibrinolytic activation and microvascular derangement in rat gastric mucosa

The roles for the fibrinolytic activation and disorder of coagulation in formation of gastric ulcer induced by microvascular derangement were investigated. The rat stomach was exposed and repeated electrical stimuli (RES) were applied on the small arterial wall close to the lesser curvature to induce mucosal microcirculatory disturbances. The level of tissue-type plasminogen activator (t-PA), a key enzyme for fibrinolytic activity, in the regional blood of the stomach was significantly elevated immediately after RES. At 5 min after RES, the leakage of FITC-labeled albumin and thrombus formation in the mucosal microvasculature were visually demonstrated by using an intravital microscopic system. At 30 min, hemorrhagic erosions and linear ulcers were observed in the gastric mucosa. Pretreatment with human antithrombin-III (AT-III) in the range of 0.1-10 U/kg dose-dependently attenuated both the fibrinolytic activation and microvascular alteration promoted by RES. Human AT-III also prevented RES-induced gastric mucosal injury. Thrombin inhibitory activity in the gastric vein decreased (69.0 +/- 2.1%) just after RES, and further reduced at 30 min (47.7 +/- 5.3%). The present study suggests a hypothesis that human AT-III has a preventive effect on the gastric mucosal hemorrhagic changes via attenuating the fibrinolytic activation and subsequent microcirculatory disturbances.

Prostaglandin E1 abrogates early reductive stress and zone-specific paradoxical oxidative injury in hypoperfused rat liver

This study was designed to investigate the effects of prostaglandin E1 on reductive stress and the subsequent oxidative cell injury in hypoperfused rat liver. The intralobular heterogeneity of hepatocellular redox state, mitochondrial dysfunction, and intracellular hydroperoxide formation were visually monitored by digital microfluorography of pyridine nucleotide autofluorescence, rhodamine 123, and dichlorofluorescein fluorescence, respectively. Under the 25% low flow perfusion, pyridine nucleotide autofluorescence increased time-dependently and reached a steady state at 10 min among the entire lobules. The decrease in mitochondrial membrane potential was > 20 mV in all portions of the lobules at 60 min. The onset of hydroperoxide formation was observed at 40 min in the marginally oxygenated proximal portion of anoxic pericentral regions and the oxidative impact reached a maximum level at 60 min. Sodium (-)-8-(3-methoxy-4-phenylsulfinylphenyl) pyrazo [1,5-a]-1,3,5-triazine-4-olate monohydrate (BOF 4272), a novel xanthine oxidase inhibitor, suppressed the zone-specific oxidative changes without attenuating the increase in pyridine nucleotide autofluorescence and mitochondrial dysfunction. Pretreatment with prostaglandin E1 not only abrogated an early increase in pyridine nucleotide fluorescence and mitochondrial dysfunction induced by hypoperfusion but also diminished the subsequent midzonal oxidative injury. Since prostaglandin E1 has no oxyradical-scavenging action, the preventive effect of this reagent on the hypoxia-induced oxidative cell injury is attributable to the attenuation of mitochondrial dysfunction. These results suggest that, in low flow hypoxia, early reductive stress plays a key role in the initiation of xanthine oxidase-mediated midzonal oxidative changes, which may lead to subsequent centrilobular necrosis.

Increased chemiluminescence and ulcer development in the low blood flow state of the gastric tube for esophageal replacement

Peptic ulcers in the gastric tube for esophageal replacement develop in spite of reduction of acid secretion after truncal vagotomy and often result in serious conditions such as bleeding and perforation. Thirteen cases of gastric tube ulcers were detected endoscopically from 1985 to 1990 in our hospital. Most of these ulcers developed within 20 cm of the anastomosis (esophagogastrostomy), which was an especially hypoxic and ischemic area. Ischemic change due to decreased blood supply is suggested as a causative factor in ulcer development. Recent studies indicate that chemiluminescence (ChL) activity may increase even in the low-flow hypoxic condition. Therefore, we investigated the ChL of regional blood in the hypoxic gastric tube in dogs. The ChL activity of the blood sample collected from the ischemic region in the gastric tube significantly increased after construction of the gastric tube, compared with systemic blood from the femoral vein, and the number of leukocytes decreased in the ischemic region. We believe that oxygen radicals derived from neutrophils adhering to the vascular endothelium may play an important role in the damage to endothelial cells of the gastric tube and suggest the possibility of their causative effects in the process of ulcer formations.

Revaluation of endoscopic laser therapy for treatment of early cancer in the stomach

The efficacy and safety of the endoscopic laser therapy for eradication of early cancer in the stomach was revaluated in fourty-eight patients. In 37 of the 42 patients (88%) treated with the laser therapy alone, the procedure was effective and the complete eradication was confirmed at the end of the follow-up period. In seven of fourteen patients with the incomplete treatment, residual cancer cells were successfully removed by repeated laser therapy. The endoscopic mucosal resection was effective in 21 of the 30 patients (70%) with the early gastric cancer. Interestingly, six of the eleven cases with incomplete treatment with the endoscopic mucosal resection underwent the laser therapy and the complete eradication was achieved in all patients. Although the endoscopic mucosal resection is now the main method for the endoscopic treatment of the early gastric cancer, these data favor offering the endoscopic laser therapy as the combined method with the mucosal resection therapy.

Binding sites for calcitonin gene-related peptide in regenerating gastric mucosa

To clarify the effector sites and significance of calcitonin gene-related peptide (CGRP) in the gastric mucosa, the specific binding sites of CGRP in the rat stomach were studied with autoradiography of soluble compounds and in vitro autoradiography. Binding sites for CGRP in the stomach were seen on the vascular smooth-muscle cells of the arterioles and venules, on the nonvascular smooth-muscle cells of the muscularis mucosae, and on the longitudinal layer of the muscularis propriae. After acetic acid treatment, the number of silver grains was significantly increased in the regenerated mucosa. These data support the significant role of CGRP in the regulation of cytoprotection of the stomach through an increase in the microcirculatory blood flow and through extended smooth-muscle relaxation.

Mechanisms of endothelin-induced macromolecular leakage in microvascular beds of rat mesentery

Microvascular responses to endothelin-3 were investigated in the rat mesentery under fluorescence microscopy. Endothelin-3 in a range of 0.1-100 pM induced arteriolar constriction in a dose-dependent manner, and stimulated Ca2+ mobilization, demonstrated by fura-2-associated fluorography, in both arterioles and venules. Cyclo(-D-Trp-D-Asp-Pro-D-Val-Leu-) (BQ123), and endothelin ETA receptor antagonist, at a concentration of 10 microM inhibited the endothelin-3 (100 pM)-induced arteriolar constriction and Ca2+ mobilization in arterioles but not in venules. In venules, an early onset leakage of FITC (fluorescein isothiocyanate)-labeled albumin and subsequent reduction of red blood cell velocity without arteriolar constriction were observed after the superfusion of endothelin-3 with BQ123, suggesting that a non-endothelin ETA receptor mediates macromolecular leakage followed by a decrease in blood flow. Endothelin-3 with BQ123 neither stimulated leukocyte adhesion nor activated luminol-dependent chemiluminescence in venules, showing that endothelin-3-increased permeability may be induced by leukocyte-independent and oxyradical-independent mechanisms. These microvascular alterations of permeability and red blood cell velocity were significantly attenuated by the addition of phalloidin, an F-actin stabilizer, suggesting the involvement of endothelial cell contraction. Nicardipine (1,4-dihydro-2,6-dimethyl-4-[3-nitrophenyl]methyl-2- [methyl(phenylmethyl)amino]-3,5-pyridinedicarboxylic acid ethyl ester), a dihydropyridine-type Ca2+ channel antagonist, eliminated endothelin-3-induced arteriolar constriction; however, it did not affect albumin leakage promoted by endothelin-3 with BQ123, suggesting that a non-voltage-dependent Ca2+ channel(s) is involved in non-endothelin ETA receptor-mediated Ca2+ mobilization and contraction of venular endothelial cells. Overall, it is conceivable that endothelin ETA receptor and voltage-dependent Ca2+ channel are involved in endothelin-3-induced arteriolar constriction. In addition, the present results suggest that Ca2+ mobilization in venular endothelium, which is mediated by a non-endothelin ETA receptor, possibly endothelin ETB receptor and regulated by non-voltage-dependent Ca2+ channel(s), may cause endothelial cell contraction and subsequently increase macromolecular permeability in microvascular beds treated with endothelin-3.

Influence of fatty acid absorption on bidirectional release of immunoglobulin A into intestinal lumen and intestinal lymph in rats

Effects of absorption of long and middle chain fatty acids on IgA secretion into the intestinal lumen and intestinal lymph and the factors which evoke changes in IgA secretion during the absorptive process were examined in rat small intestine. Bidirectional secretion of IgA from the intestinal mucosa into the intestinal lumen and intestinal lymph was continuously observed in the control condition. Perfusion of oleic acid (a long-chain fatty acid) micelle into the jejunal loop induced a significant increase in IgA output into the intestinal lymph. In contrast, lymphatic output of IgA was significantly decreased when oleic acid micelle was administered intraduodenally. Absorption of octanoic acid, a middle-chain fatty acid, did not produce any significant changes in IgA output into either direction. CR1505, a CCK-receptor antagonist, significantly attenuated the oleic acid-induced increase in IgA secretion into the intestinal lumen, but did not affect the oleic acid-induced decrease in lymphatic IgA secretion. Pluronic L-81, an inhibitor of chylomicron formation and secretion, significantly attenuated the decrease in IgA output into the intestinal lymph during oleic acid absorption without affecting the luminal IgA output. The rate of release of IgA into the intestinal lumen is stimulated by absorption of long-chain fatty acids possibly through the influence of locally released CCK, while the transport process of IgA into lymphatics is controlled by a different mechanism which is closely correlated with the intracellular formation and secretion of chylomicron.

Structural and dynamic membrane properties of alpha-tocopherol and alpha-tocotrienol: implication to the molecular mechanism of their antioxidant potency

d-alpha-Tocopherol and d-alpha-tocotrienol are two vitamin E constituents having the same aromatic chromanol "head" but different hydrocarbon "tails". alpha-Tocotrienol has been shown to be more potent in protecting against free radical-induced oxidative stress than alpha-tocopherol. Simple models of phospholipid membrane systems were used to investigate the mechanism of the antioxidant potency of alpha-tocotrienol in terms of its effects on membrane order and reorientation dynamics. Chemiluminescence and fluorescence measurements demonstrated that alpha-tocotrienol exhibits significantly greater peroxyl radical scavenging potency than alpha-tocopherol in phosphatidylcholine liposomes, whereas both antioxidants have identical activity in hexane. This suggests that the antioxidant potency of alpha-tocotrienol requires the membrane environment. When alpha-tocopherol and alpha-tocotrienol were examined for their effects on phospholipid molecular order using conventional ESR spin labeling with 5- and 16-position-labeled doxylstearic acid, although both vitamin E constituents disordered the gel phase and stabilized the liquid-crystalline phase, no differences were observed between the effects of the two compounds. A slightly greater increase (19% vs 15%) in ordering of the liquid-crystalline state due to alpha-tocopherol, however, was discerned in noninvasive 2H NMR experiments. The difference is most noticeable near C10-C13 positions of the phospholipid chain, possibly suggesting alpha-tocotrienol is located closer to the membrane surface. Saturation-transfer ESR, furthermore, revealed that on the time scale tau c = 10(-7)-10(-3) s the rates of rotation about the long molecular axis and of the wobbling motion of the axis are modified to differing extents by the two forms of the vitamin E.(ABSTRACT TRUNCATED AT 250 WORDS)

Thymectomy in human renal transplantation

We reviewed 17 patients submitted to thymectomy via the suprasternal notch (Yoshimatsu Method I), which was performed before transplantation in 12 patients and after transplantation in 5 patients. There were no complications of thymectomy. Graft survival of our patients with thymectomy was better than that for the overall allograft survival in Japan transplant registry for the same period. Pathologic studies revealed that involution of the cortex was not observed in 5 thymuses removed from recipients who had thymectomy after transplantation even though 2 of them had received 6.4 g and 3.5 g of prednisolone for 19 months and 32 months, respectively.

Nitric oxide mediates lipopolysaccharide-induced alteration of mitochondrial function in cultured hepatocytes and isolated perfused liver

The influence of endogenous nitric oxide, which is generated by stimulation with lipopolysaccharide, on the mitochondrial energization of rat hepatocytes was investigated in vitro and ex vivo. Using a fluorescence microscope equipped with a silicon intensifier target camera, we visualized fluorescence of rhodamine-123, a mitochondrial energization-sensitive fluorescence probe, in individual hepatocytes and measured the fluorescence intensity with a digital imaging processor. Although addition of Kupffer cells or lipopolysaccharide in a range of 0.1 to 1.0 microgram/ml caused no significant alteration in the fluorescence in hepatocytes, Kupffer cells plus 1.0 microgram/ml lipopolysaccharide reduced fluorescence intensity in the cocultured hepatocytes. The alteration of rhodamine-123 fluorescence in the hepatocytes induced by lipopolysaccharide-activated Kupffer cells was significantly inhibited by the addition of NG-monomethyl-L-arginine, a selective inhibitor of nitric oxide synthesis. The transportal infusion of lipopolysaccharide also decreased rhodamine-123 fluorescence in perfused rat liver. The decrease was significantly enhanced in the pericentral regions. Autofluorescence of NADH was elicited by continuous infusion of lipopolysaccharide; this reaction was also enhanced in the pericentral regions. We showed the main site of uptake of infused lipopolysaccharide in the hepatic lobule to be in the periportal regions with fluorescein isothiocyanate-labeled lipopolysaccharide. Our results indicate that the inhibition of mitochondrial energization occurs mainly in pericentral regions, which are distant from the lipopolysaccharide uptake site. The continuous administration of NG-monomethyl-L-arginine significantly attenuated the lipopolysaccharide-induced decrease in rhodamine-123 fluorescence and increase of the NADH contents of the hepatic lobule.(ABSTRACT TRUNCATED AT 250 WORDS)

Genioglossus muscle activity and inspiratory timing in obstructive sleep apnea

Atypical tongue muscle activity during sleep may contribute to the development of obstructive sleep apnea (OSA). Inspiratory genioglossus (GG) muscle activity was investigated in 10 OSA adults and 4 symptom-free controls. On the basis of overnight monitoring during nonREM sleep, the duration of the inspiratory GG activity and the total GG activity cycle is shorter in patients with OSA. The duration of inspiration and the duration of one total respiratory cycle is also shorter in patients with OSA. The commencement time lag between inspiratory GG activity and the onset of inspiration is shorter in patients with OSA during nonapneic breathing which indicates that inspiratory GG activity is activated relatively later in these patients. Furthermore, the inspiratory GG activity occurs after inspiration during an apnea, but the timing of GG activity onset progressively advances during the apnea. Earlier GG reactivation occurs before inspiration during the first nonoccluded breath at the end of an apnea. During subsequent tidal breathing, the timing of the GG onset progressively decreases after the onset of inspiration until the next obstructive apnea occurs. This observation suggests that the timing relationship between GG inspiratory activity and inspiratory effort is of physiologic importance in the pathogenesis of OSA. Furthermore, it may explain why dental appliances, such as the tongue retaining device, are highly effective in the resolution of OSA in selected patients.

Synthesis and anthelmintic activity of 13-alkoxymilbemycin derivatives

The synthesis of milbemycin derivatives having alkyloxy groups at the C-13 position was studied and a series of these analogs of milbemycin A4 and A3 was prepared by the reaction of 13-iodomilbemycin with a variety of alcohols. 13 beta-Phenethyloxy derivatives were found to possess excellent anthelmintic activity. Especially, the activities of derivatives with N-substituted 4-aminophenethyloxy groups were comparable to or superior to ivermectin against Nippostrongylus brasiliensis in rats.

Carcinoembryonic antigen mediates in vitro cell aggregation induced by interferon-gamma in a human colon cancer cell line: requirement for active metabolism and intact cytoskeleton

The homotypic cell aggregation of a carcinoembryonic antigen (CEA) positive colon cancer cell line (Colo 205) was induced in vitro by interferon-gamma (IFN-gamma) treatment. Divalent cations were required for this aggregation, as it was inhibited by EDTA. The partial inhibition by cytochalasin B and the complete inhibition by a mixture of sodium azide and 2-deoxyglucose suggests that the aggregation requires the integrity of cytoskeleton and active metabolism. The expression of CEA was increased in the cytoplasm and on the membrane of Colo 205 by IFN-gamma treatment. Furthermore, this aggregation was inhibited completely by anti-CEA monoclonal antibody (mAb) and partially by mAb against intercellular adhesion molecule-1. This in vitro study suggests that CEA molecule participates in the IFN-gamma induced homotypic adhesion of some CEA positive cancer cells and that IFN-gamma has an important role in the regulation of cell-cell interaction mediated by CEA molecule.

Regional differences in microvascular response in rat intestine during acute elevation of portal pressure

The effect of acute elevation of portal pressure on the blood flow of rat intestinal microvessels was studied using a laser Doppler velocimeter and in vivo microscopy. The total intestinal blood flow decreased when portal pressure increased more than +15 cmH2O above the basal value. Blood flow in villus capillaries did not change at portal pressures of +5 to +15 cmH2O, but did decrease at +20 cmH2O. Blood flow in muscle capillaries decreased at all steps of portal hypertension. Red blood cell velocity was decreased by portal hypertension in large venules, but not in small venules of the submucosa. Large venules, but not small venules, dilated in acute portal hypertension. Large arterioles in the submucosa constricted, while small arterioles dilated at portal pressures of +10 to +15 cmH2O. In conclusion, the intestinal microvascular flow response differs according to the degree of portal hypertension and the location on the microvascular tree. Blood flow in villus capillaries and in small submucosal venules is maintained at a small degree of portal hypertension.

Immunohistochemical study of thymic B cells in myasthenia gravis and ulcerative colitis

The phenotypes of B cells and dendritic cells in human thymus were examined immunohistochemically using various monoclonal antibodies. Normal thymus contained a few B lymphocytes recognized by CD19, CD20, CD22, L26 and LN-2, which were localized in the medulla. These B cells were negative for LN-1, L30 and CD11c (Leu M5). Activated B cells recognized by CD23 (B6) and L29 antibodies were not present in normal thymus. Dendritic cells stained by CD11c were weakly positive for L26 and CD20. There was no difference in the distribution of dendritic cells between normal thymus and thymus from the patients. In the thymus from patients with myasthenia gravis, numerous B cells were demonstrated in the medullary area and lymphoid follicles. Activated B cells were seen mainly in the germinal center of lymphoid follicles and were scarce in the medulla. Many B cells were also found in the medulla and lymphoid follicles of the thymus from patients with ulcerative colitis. However most of those B cells were not activated, even in the lymphoid follicles. These results suggest that thymic B cells may contribute to the induction of immune abnormalities in patients with myasthenia gravis and those with ulcerative colitis, however, the mechanisms by which thymic B cells participate in the pathogenesis of these two diseases would be different.

Local cerebral glucose utilisation following acute and chronic bilateral carotid artery ligation in Wistar rats: relation to changes in local cerebral blood flow

The effects on local cerebral blood flow (LCBF) and glucose utilisation (LCGU) of permanent, bilateral carotid artery ligation (BCAL) were studied in conscious Wistar rats. LCBF and LCGU were measured using quantitative autoradiographic 14C-iodoantipyrine and the 14C-2-deoxyglucose (14C-DG) techniques in 24 anatomically discrete regions of the brain. LCBF in the cerebral hemispheres 2.5 h (acute) after BCAL significantly decreased to 25-87% of the sham control, with the exception of the mammillary body. After acute BCAL, there was a heterogeneous accumulation of 14C-DG in the caudate nucleus and cerebral cortices. Only in the lateral geniculate body did LCGU significantly decrease after BCAL. One week (chronic) later, LCBF was significantly decreased in 15 (containing the caudate nucleus and all the cerebral cortices) of 24 structures. LCGU in ten (containing the caudate nucleus and all the cerebral cortices) of 24 structures after chronic BCAL significantly decreased to 66-77% of the sham control, except for regions with neuronal damage in which there was a heterogeneous uptake of 14C-DG. The ratio of LCBF/LCGU in chronic BCAL was unchanged in comparison with values in the corresponding sham-operated group. This model of acute and chronic cerebral ischaemia, with impairment in cerebral circulation and/or glucose metabolism, is expected to become a pertinent tool for the neurophysiologist.

Intravital and electron microscopic observation of Ito cells in rat hepatic microcirculation

Intralobular distribution of Ito cells (fat-storing cells) in hepatic microcirculatory units was investigated through intravital fluorescence microscopy. By using a low-level ultraviolet epi-illumination and a sensitive silicon intensified target camera, the intrahepatic autofluorescence was visualized and digitally processed. In rats fed an ordinary diet, the ultraviolet-excited autofluorescence was composed of at least two different origins that could not be spectrophotometrically distinguished, namely, multiple patchy autofluorescence activities along the sinusoids and terminal hepatic venules and diffuse parenchymal autofluorescence. Multiple patchy activities showed a rapid photobleaching phenomenon under the continuous ultraviolet excitation. These fluorescent activities were completely eliminated by depleting the intrahepatic retinoid contents using a vitamin A-deficient diet for 4 weeks. Furthermore repeated administration of vitamin A significantly enhanced the patchy fluorescent activities. Electron microscopy revealed that these vitamin A fluorescent activities are colocalized with the fat droplets in Ito cells, providing evidence that Ito cells exist not only in perisinusoidal spaces but also in the perivascular spaces of the terminal hepatic and portal venules. The current intravital technique thus provides a new method to observe Ito cells in hepatic microcirculatory units in vivo.

Xanthine oxidase-mediated intracellular oxidative stress in response to cerulein in rat pancreatic acinar cells

Intralobular oxygen radical formation was examined in cerulein-stimulated rat pancreatic acinar cells by digital imaging microscopic fluorography using a hydroperoxide-sensitive fluorescent probe, dichlorofluorescin (DCFH) diacetate. The isolated pancreatic acinar cells loaded with DCFH diacetate were microscopically observed, and the dichlorofluorescein (DCF) fluorescence yielded by DCFH oxidation via hydroperoxides was digitally processed. Within the initial 20 min after the application of cerulein (10 microM), intracellular oxidative stress was observed as indicated by the increase in DCF fluorescence intensity and reached its maximum at 60 min. DCF fluorescence intensity was then gradually decreased until 80 min, followed by a marked increase in propidium iodide (PI) fluorescence, suggesting irreversible cell death. Allopurinol (1 microM), a xanthine oxidase inhibitor, significantly attenuated the early increase of DCF fluorescence intensity as well as the late cell damage. Treatment with hyperbaric oxygen (PO2 300 mm Hg) also significantly attenuated both the increase of DCF fluorescence and the number of PI-positive cells. The results suggest that xanthine oxidase-mediated oxygen radicals may play an important role in cerulein-induced intracellular oxidative stress in pancreatic acinar cells of rats.

Nitric oxide mediates vasoactive effects of endothelin-3 on rat mesenteric microvascular beds in vivo

In order to clarify whether the vasoactive effects of endothelin-3 (ET-3) on microvessels are associated with the endothelium-derived relaxing factor (EDRF) in vivo, the authors examined the effects of L-NG-monomethyl arginine (L-NMMA), an analog of L-arginine, on low-dose ET-3 induced hemodynamic changes in the mesenteric microcirculation of male Wistar rats. The intravital observation revealed that ET-3 100 pM induced a remarkable and periodic vasoconstriction in arterioles, and the constriction was sustained for approximately fifteen minutes. No remarkable change was observed in the microvessels after the superfusion of 1 pM ET-3. Superfusion of 1 pM ET-3 with 100 microM L-NMMA elicited the vasoconstriction in arterioles, and the arteriolar diameter recovered to the control level within ten minutes in spite of continuing the superfusion. The vasoconstriction induced by low-dose ET-3 with L-NMMA was suppressed by the additional superfusion of 200 microM L-arginine. The present study suggests that the recovery of arteriolar diameter after the ET-3-induced constriction may be mediated by nitric oxide at least in the early phase.