The Combination of Cholecystokinin and Stress Amplifies an Inhibition of Appetite, Gastric Emptying, and an Increase in c-Fos Expression in Neurons of the Hypothalamus and the Medulla Oblongata

Cholecystokinin (CCK) had been the first gastrointestinal hormone known to exert anorexic effects. CCK had been inferred to contribute to the onset of functional dyspepsia (FD) symptoms. To understand the pathophysiology of FD, the roles of stress have to be clarified. In this study, we aimed to clarify the influence of stress on the action of cholecystokinin (CCK) on appetite and gastric emptying. Using rats, stress was simulated by giving restraint stress or intraperitoneal injection of the stress-related peptide hormone urocortin 1 (UCN1). The effects of CCK and restraint stress, alone or in combination, on food intake and gastric motility were examined, and c-Fos expression in the neurons of appetite control network in the central nervous system was assessed by immunohistochemical staining. CCK inhibited food intake and gastric emptying in a dose-dependent manner. Food intake for 1 h was significantly lower with UCN1 (2 nmol/kg) than with the saline control. Restraint stress amplified the suppressive effects of CCK on food intake for 1 h and on gastric emptying. With regard to brain function, the CCK induced c-Fos expression in the neurons of the nucleus tractus solitarius and paraventricular nucleus of the hypothalamus was markedly and significantly amplified by the addition of restraint stress with CCK. The results suggested that stress might amplify the anorexic effects of CCK through activation of the nuclei that comprise the brain neuronal network for satiation; this might play a role in the pathogenesis of the postprandial distress syndromes of functional dyspepsia.

IL-9 Blockade Suppresses Silica-induced Lung Inflammation and Fibrosis in Mice

Recapitulative animal models of idiopathic pulmonary fibrosis (IPF) and related diseases are lacking, which inhibits our ability to fully clarify the pathogenesis of these diseases. Although lung fibrosis in mouse models is often induced by bleomycin, silica-induced lung fibrosis is more sustainable and more progressive. Therefore, in this study, we sought to elucidate the mediator(s) responsible for the pathogenesis of lung fibrosis, through the use of a mouse model of silica-induced lung fibrosis. With a single nasal administration of 16 mg of silica, lung inflammation (assessed by elevated cellular components in the BAL fluids [BALFs]) and lung fibrosis (assessed by lung histology and lung hydroxyproline levels) were induced and sustained for as long as 24 weeks. Of the mediators measured in the BALFs, IL-9 was characteristically elevated gradually, and peaked at 24 weeks after silica administration. Treatment of silica-challenged mice with anti-IL-9-neutralizing antibody inhibited lung fibrosis, as assessed by lung hydroxyproline level, and suppressed the levels of major mediators, including IL-1β, IL-6, IL-12, CCL2, CXCL1, and TNF-α in BALFs. Moreover, human lung specimens from patients with IPF have shown high expression of IL-9 in alveolar macrophages, CD4-positive cells, and receptors for IL-9 in airway epithelial cells. Collectively, these data suggest that IL-9 plays an important role in the pathogenesis of lung fibrosis in diseases such as IPF.

Leukotriene receptor antagonist attenuated airway inflammation and hyperresponsiveness in a double-stranded RNA-induced asthma exacerbation model

BACKGROUND

Viral infections are the most common triggers of asthma exacerbation, but the key molecules involved in this process have not been fully identified. Although cysteinyl leukotrienes (cysLTs) have been postulated as the key mediators, their precise roles remain largely unclear. To investigate the roles of cysLTs in virus-induced asthma exacerbation, we developed a murine model using a viral double-stranded RNA analog, polyinosinic-polycytidylic acid (poly I:C), and analyzed the effect of leukotriene receptor antagonist (LTRA) administration.

METHODS

A/J mice were immunized with ovalbumin (OVA) + alum (days 0, 28, 42, and 49), followed by intranasal challenge with OVA (phase 1: days 50-52) and poly I:C (phase 2: days 53-55). Montelukast was administered during poly I:C challenge (phase 2) in the reliever model or throughout the OVA and poly I:C challenges (phases 1 and 2) in the controller model. Airway responsiveness to acetylcholine chloride was assessed, and bronchoalveolar lavage (BAL) was performed on day 56.

RESULTS

Administration of poly I:C to OVA-sensitized and -challenged mice increased the number of eosinophils and levels of IL-13, IL-9, CCL3, and CXCL1 in BAL fluid (BALF) and tended to increase airway responsiveness. Montelukast significantly attenuated the poly I:C-induced increase in the number of eosinophils and levels of IL-13, IL-9, and CCL3 in BALF and airway hyperresponsiveness in both the reliever and controller models.

CONCLUSIONS

This is the first report showing that LTRA functionally suppressed the pathophysiology of a virus-induced asthma exacerbation model, suggesting the importance of cysLTs as a potential treatment target.

Thoracoscopy under Local Anesthesia was Useful for Diagnosing Yellow Nail Syndrome

An 80-year-old woman with rheumatoid arthritis and a past history of tuberculosis presented with exertional dyspnea and edema of both legs. Chest X-ray performed on admission showed bilateral pleural effusion. Thoracoscopy under local anesthesia was performed, and vasodilation and non-specific yellowish inflammatory changes were noted in the pleura. A pathological examination showed chronic fibrosing pleuritis in addition to chronic pleural inflammatory changes with lymphoid aggregates. The nails on all fingers and toes were thickened and displayed yellow discoloration, and the edema was resistant to diuretics. Lymphoscintigraphy was conducted, which showed lymphatic drainage abnormalities. The patient was ultimately diagnosed as having yellow nail syndrome.

Ghrelin enhancer, rikkunshito, improves postprandial gastric motor dysfunction in an experimental stress model

BACKGROUND

Functional dyspepsia (FD) is one of the most common disorders of gastrointestinal (GI) diseases. However, no curable treatment is available for FD because the detailed mechanism of GI dysfunction in stressed conditions remains unclear. We aimed to clarify the association between endogenous acylated ghrelin signaling and gastric motor dysfunction and explore the possibility of a drug with ghrelin signal-enhancing action for FD treatment.

METHODS

Solid gastric emptying (GE) and plasma acylated ghrelin levels were evaluated in an urocortin1 (UCN1) -induced stress model. To clarify the role of acylated ghrelin on GI dysfunction in the model, exogenous acylated ghrelin, an endogenous ghrelin enhancer, rikkunshito, or an α2 -adrenergic receptor (AR) antagonist was administered. Postprandial motor function was investigated using a strain gauge force transducer in a free-moving condition.

KEY RESULTS

Exogenous acylated ghrelin supplementation restored UCN1-induced delayed GE. Alpha2 -AR antagonist and rikkunshito inhibited the reduction in plasma acylated ghrelin and GE in the stress model. The action of rikkunshito on delayed GE was blocked by co-administration of the ghrelin receptor antagonist. UCN1 decreased the amplitude of contraction in the antrum while increasing it in the duodenum. The motility index of the antrum but not the duodenum was significantly reduced by UCN1 treatment, which was improved by acylated ghrelin or rikkunshito.

CONCLUSIONS & INFERENCES

The UCN1-induced gastric motility dysfunction was mediated by abnormal acylated ghrelin dynamics. Supplementation of exogenous acylated ghrelin or enhancement of endogenous acylated ghrelin secretion by rikkunshito may be effective in treating functional GI disorders.

Takotsubo Cardiomyopathy and Subsequent Seizures Induced by Flexible Bronchoscopy

Takotsubo cardiomyopathy is a transient left-ventricular dysfunction that typically occurs in elderly women due to emotional or physical stress. An 85-y-old woman underwent flexible bronchoscopy to evaluate her malignant lymphoma. After flexible bronchoscopy, she experienced takotsubo cardiomyopathy diagnosed by left ventriculography and subsequent generalized tonic-clonic seizure diagnosed by electroencephalography. Magnetic resonance imaging of her brain after 1 d showed post-convulsive encephalopathy. We believe that these 2 consecutive incidents were caused by the physical stress of the flexible bronchoscopy.

The importance of bacterial and viral infections associated with adult asthma exacerbations in clinical practice

BACKGROUND

Viral infection is one of the risk factors for asthma exacerbation. However, which pathogens are related to asthma exacerbation in adults remains unclear.

OBJECTIVE

The relation between various infections and adult asthma exacerbations was investigated in clinical practice.

METHODS

The study subjects included 50 adult inpatients due to asthma exacerbations and 20 stable outpatients for comparison. The pathogens from a nasopharyngeal swab were measured by multiplex PCR analysis.

RESULTS

Asthma exacerbations occurred after a common cold in 48 inpatients. The numbers of patients with viral, bacterial, or both infections were 16, 9, and 9, respectively. The dominant viruses were rhinoviruses, respiratory syncytial virus, influenza virus, and metapneumovirus. The major bacteria were S. pneumoniae and H. influenzae. Compared to pathogen-free patients, the patients with pathogens were older and non-atopic and had later onset of disease, lower FeNO levels, lower IgE titers, and a higher incidence of comorbid sinusitis, COPD, or pneumonia. Compared to stable outpatients, asthma exacerbation inpatients had a higher incidence of smoking and comorbid sinusitis, COPD, or pneumonia. Viruses were detected in 50% of stable outpatients, but a higher incidence of rhinovirus, respiratory syncytial virus, and metapneumovirus infections was observed in asthma exacerbation inpatients. H. influenzae was observed in stable asthmatic patients. Other bacteria, especially S. pneumoniae, were important in asthma exacerbation inpatients.

CONCLUSION

Viral or bacterial infections were observed in 70% of inpatients with an asthma exacerbation in clinical practice. Infection with S. pneumoniae was related to adult asthma exacerbation.

Peripheral α2-β1 adrenergic interactions mediate the ghrelin response to brain urocortin 1 in rats

The autonomic nervous system (ANS) conveys neuronal input from the brain to the stomach. We investigated mechanisms through which urocortin 1 (UCN1) injected intracerebroventricularly (ICV, 300 pmol/rat) inhibits circulating ghrelin in rats. This was achieved by assessing (1) the induction of c-fos gene expression as a marker of neuronal activation in specific hypothalamic and caudal brainstem regulating ANS; (2) the influence of vagotomy and pharmacological blockade of central and peripheral α- and β-adrenergic receptor (AR) on ICV UCN1-induced reduction of plasma ghrelin levels (determined by ELISA); and (3) the relevance of this pathway in the feeding response to a fast in rats. UCN1 increased c-fos mRNA expression in key brain sites influencing sympathetic activity namely the hypothalamic paraventricular and ventromedial nuclei, locus coeruleus, nucleus of the solitary tract, and rostral ventrolateral medulla, by 16-, 29-, 6-, 37-, and 13-fold, respectively. In contrast, the dorsal motor nucleus of the vagus had little c-fos mRNA expression and ICV UCN1 induced a similar reduction in acylated ghrelin in the sham-operated (31%) and vagotomized (41%) rats. An intraperitoneal (IP) injection of either a non-selective α- or selective α2-AR antagonist reduced, while a selective α2-AR agonist enhanced ICV UCN1-induced suppression of plasma acylated ghrelin levels. In addition, IP injection of a non-selective β- or selective β1-AR agonist blocked, and selective β1-AR antagonist augmented, the ghrelin response to ICV UCN1. The IP injections of a selective α1- or non-selective β or β2-AR antagonists, or any of the pretreatments given ICV had no effect. ICV UCN1 reduced the 2-h food intake in response to a fast by 80%, and this effect was partially prevented by a selective α2-AR antagonist. These data suggest that ICV UCN1 reduces plasma ghrelin mainly through the brain sympathetic component of the ANS and peripheral AR specifically α2-AR activation and inactivation of β1-AR. The α2-AR pathway contributes to the associated reduction in food intake.

Urocortin1-induced anorexia is regulated by activation of the serotonin 2C receptor in the brain

This study was conducted to determine the mechanisms by which serotonin (5-hydroxytryptamine, 5-HT) receptors are involved in the suppression of food intake in a rat stress model and to observe the degree of activation in the areas of the brain involved in feeding. In the stress model, male Sprague-Dawley rats (8 weeks old) were given intracerebroventricular injections of urocortin (UCN) 1. To determine the role of the 5-HT2c receptor (5-HT2cR) in the decreased food intake in UCN1-treated rats, specific 5-HT2cR or 5-HT2b receptor (5-HT2bR) antagonists were administered. Food intake was markedly reduced in UCN1-injected rats compared with phosphate buffered saline treated control rats. Intraperitoneal administration of a 5-HT2cR antagonist, but not a 5-HT2bR antagonist, significantly inhibited the decreased food intake. To assess the involvement of neural activation, we tracked the expression of c-fos mRNA as a neuronal activation marker. Expression of the c-fos mRNA in the arcuate nucleus, ventromedial hypothalamic nucleus (VMH) and rostral ventrolateral medulla (RVLM) in UNC1-injected rats showed significantly higher expression than in the PBS-injected rats. Increased c-fos mRNA was also observed in the paraventricular nucleus (PVN), the nucleus of the solitary tract (NTS), and the amygdala (AMG) after injection of UCN1. Increased 5-HT2cR protein expression was also observed in several areas. However, increased coexpression of 5-HT2cR and c-fos was observed in the PVN, VMH, NTS, RVLM and AMG. Whereas, pro-opiomelanocortin mRNA expression was not changed. In an UNC1-induced stress model, 5-HT2cR expression and activation was found in brain areas involved in feeding control.

Urocortin 1 reduces food intake and ghrelin secretion via CRF(2) receptors

Although it is known that urocortin 1 (UCN) acts on both corticotropin-releasing factor receptors (CRF(1) and CRF(2)), the mechanisms underlying UCN-induced anorexia remain unclear. In contrast, ghrelin, the endogenous ligand for the growth hormone secretagogue receptor, stimulates food intake. In the present study, we examined the effects of CRF(1) and CRF(2) receptor antagonists (CRF(1)a and CRF(2)a) on ghrelin secretion and synthesis, c-fos mRNA expression in the caudal brain stem, and food intake following intracerebroventricular administration of UCN. Eight-week-old, male Sprague-Dawley rats were used after 24-h food deprivation. Acylated and des-acylated ghrelin levels were measured by enzyme-linked immunosorbent assay. The mRNA expressions of preproghrelin and c-fos were measured by real-time RT-PCR. The present study provided the following important insights into the mechanisms underlying the anorectic effects of UCN: 1) UCN increased acylated and des-acylated ghrelin levels in the gastric body and decreased their levels in the plasma; 2) UCN decreased preproghrelin mRNA levels in the gastric body; 3) UCN-induced reduction of plasma ghrelin and food intake were restored by CRF(2)a but not CRF(1)a; 4) UCN-induced increase of c-fos mRNA levels in the caudal brain stem containing the nucleus of the solitary tract (NTS) was inhibited by CRF(2)a; and 5) UCN-induced reduction of food intake was restored by exogenous ghrelin and rikkunshito, an endogenous ghrelin secretion regulator. Thus, UCN increases neuronal activation in the caudal brain stem containing NTS via CRF(2) receptors, which may be related to UCN-induced inhibition of both ghrelin secretion and food intake.

Comparison of the actions of acylated and desacylated ghrelin on acid secretion in the rat stomach

BACKGROUND

Ghrelin, a growth-hormone-releasing peptide, has two major molecular forms: acylated (acyl) and desacylated (desacyl). Recent studies suggest different roles for these two forms. In the present study, we compared desacyl and acyl ghrelin with regard to acid secretion and histamine production in the rat stomach.

METHODS

We performed in vivo experiments using gastric lumen-perfused rats. The effects of the two forms of ghrelin on gastrin (gastrin-17)-stimulated acid secretion were also examined. Furthermore, to examine the effects of ghrelin on histamine production, histidine decarboxylase messenger ribonucleic acid in the gastric corpus mucosa was measured by reverse transcription-polymerase chain reaction.

RESULTS

Intravenous administration of acyl ghrelin at 20 μg/kg increased gastric acid secretion to 4.8 times greater than control levels. However, desacyl ghrelin had no effect on acid secretion, even at 200 μg/kg. Acyl ghrelin enhanced gastrin-stimulated acid secretion while desacyl ghrelin did not. Vagotomy markedly inhibited the enhancement of gastrin-stimulated acid secretion by acyl ghrelin. Acyl ghrelin increased histidine decarboxylase messenger ribonucleic acid concentration by 2.3 times compared with basal levels at 1 h after administration and by 2.7 times at 2 h after administration; desacyl ghrelin had no such effect. Synergism between acyl ghrelin and gastrin was seen regarding histidine decarboxylase messenger ribonucleic acid concentration.

CONCLUSIONS

The results indicate that acyl ghrelin stimulates gastric acid secretion via a mechanism involving activation of the vagus nerve and histamine release and synthesis and that desacyl ghrelin has no action on gastric acid secretion. Furthermore, the results demonstrate synergism between gastrin and acyl ghrelin in terms of gastric acid secretion via a mechanism involving histamine release and synthesis.

Reduced ghrelin secretion in the hypothalamus of rats due to cisplatin-induced anorexia

Although chemotherapy with cisplatin is a widely used and effective cancer treatment, the undesirable gastrointestinal side effects associated with it, such as nausea, vomiting, and anorexia, markedly decrease patients' quality of life. To elucidate the mechanism underlying chemotherapy-induced anorexia, focusing on the hypothalamic ghrelin secretion-anorexia association, we measured hypothalamic ghrelin secretion in fasted and cisplatin-treated rats. Hypothalamic ghrelin secretion changes after vagotomy or administration of cisplatin. Cisplatin + rikkunshito, a serotonin 2C receptor antagonist or serotonin 3 receptor antagonist, was investigated. The effects of intracerebroventricular (icv) administration of ghrelin or the serotonin 2C receptor antagonist SB242084 on food intake were also evaluated in cisplatin-treated rats. Hypothalamic ghrelin secretion significantly increased in 24-h-fasted rats compared to freely fed rats and was markedly reduced 24 and 48 h after cisplatin treatment in cisplatin-treated rats compared to saline-treated rats, although their plasma ghrelin levels were comparable. In cisplatin-treated rats, icv ghrelin administration reversed the decrease in food intake, vagotomy partially restored hypothalamic ghrelin secretion, and hypothalamic serotonin 2C receptor mRNA expression increased significantly. Administration of rikkunshito (an endogenous ghrelin enhancer) or a serotonin 2C receptor antagonist reversed the decrease in hypothalamic ghrelin secretion and food intake 24 h after cisplatin treatment. Cisplatin-induced anorexia is mediated through reduced hypothalamic ghrelin secretion. Cerebral serotonin 2C receptor activation partially induces decrease in hypothalamic ghrelin secretion, and rikkunshito suppresses cisplatin-induced anorexia by enhancing this secretion.

Rikkunshito and 5-HT2C receptor antagonist improve cisplatin-induced anorexia via hypothalamic ghrelin interaction

Circulating ghrelin concentration regulates appetite behavior, but no study thus far has focused on the role of central ghrelin in anorexia after chemotherapy. To clarify the action mechanisms of rikkunshito (RKT), a traditional Japanese medicine, on cisplatin-induced anorexia, we attempted to elucidate its effect on hypothalamic ghrelin receptor expression in cisplatin-induced anorexia. We first examined the effects of an intracerebroventricular (ICV) injection of exogenous ghrelin on food intake with or without cisplatin treatment, and the effects of cisplatin or m-chlorophenylpiperazine (mCPP), a 5-HT2C receptor agonist, on hypothalamic growth hormone secretagogue receptor 1a (GHS-R1a) mRNA expression. To identify the mechanism of cisplatin-induced decrease in hypothalamic GHS-R1a mRNA expression, we evaluated the effects of SB242084HCl, a 5-HT2C receptor antagonist, and RKT on hypothalamic GHS-R1a gene expression, along with the effect of coadministration of a GHS-R1a antagonist on decreased food intake. Compared to vehicle controls, an ICV-injected rat ghrelin failed to inhibit the decrease in food intake in cisplatin-treated rats. Hypothalamic GHS-R1a gene expression was significantly reduced after cisplatin or mCPP treatment, and the induced decrease was reversed by SB242084HCl or RKT, but not granisetron or ondansetron, both of which are 5-HT3 receptor antagonists. Their suppressive effect on the decrease in food intake was abolished by coadministration of the GHS-R1a antagonist. Administration of RKT or SB242084HCl reversed the decrease in food intake induced by mCPP injection. The improvement by RKT on decreased food intake after cisplatin treatment was partly mediated by hesperidin and isoliquiritigenin, components of RKT. Cisplatin-induced anorexia may worsen because of decreased hypothalamic GHS-R1a gene expression. A 5-HT2C receptor antagonist and RKT suppressed cisplatin-induced anorexia by inhibiting reduction of GHS-R1a signal transduction in the hypothalamus.

Circulating acylated ghrelin level decreases in accordance with the extent of atrophic gastritis

PURPOSE

We attempted to clarify the significance of atrophic change of gastric mucosa for reduction of plasma ghrelin concentration irrespective of Helicobacter pylori (Hp) infection.

METHODS

Plasma acylated (acyl-)ghrelin concentration in 220 subjects, both with and without atrophic gastritis, was measured with an enzyme immunoassay kit. The extent of atrophic change of gastric mucosa was assessed and graded endoscopically. Hp infection was determined by assay of the anti-Hp antibody with an ELISA assay kit.

RESULTS

Plasma acyl-ghrelin concentration was significantly lower in the Hp positive than the Hp negative group, and Hp eradication significantly increased plasma acyl-ghrelin concentrations in Hp positive subjects. Plasma acyl-ghrelin was significantly lower in subjects with severely atrophic gastritis than in those with mild or moderate atrophic gastritis, irrespective of Hp infection or age group (<60 years old or > or = 60 years old). In male subjects with a normal body mass index, plasma acyl-ghrelin concentrations in subjects with severely atrophic gastritis were significantly lower than those in subjects with mildly or moderately atrophic gastritis, suggesting that the results of the study are independent of emaciation or obesity. Logistic regression analysis showed that gastric atrophy is the key factor that modulates plasma acyl-ghrelin levels.

CONCLUSIONS

The results suggest that plasma acyl-ghrelin concentration decreases in accordance with the extent of atrophic change in gastric mucosa irrespective of Hp infection, indicating that the low plasma acyl-ghrelin level of subjects with Hp infection is mainly caused by the progress of atrophic changes in gastric mucosa.

Expression of c-Fos protein in the brain after intravenous injection of ghrelin in rats

In this study, we surveyed central neurons that might be activated after peripheral administration of a gut-brain peptide ghrelin, by examining neurons expressing c-Fos protein. First, we examined the relationship between the dose of ghrelin and the amount of gastric acid secreted. Ghrelin induced a significant increase in the amount of gastric acid secretion in a dose-dependent manner. Secondly, we examined central neurons that expressed c-Fos protein after intravenous injection of ghrelin. We found that intravenously injected ghrelin induced the neural expression of c-Fos protein in several nuclei and circumventricular organs in the brain. These results suggest that ghrelin released into the circulation may stimulate central neurons that have some role in the control mechanism for gastric acid secretion.

Histamine mediates the stimulatory action of ghrelin on acid secretion in rat stomach

Ghrelin, a novel growth hormone-releasing peptide, is present in the rat and human stomach and is known to stimulate acid secretion and stomach motility. However, the mechanism of action of ghrelin is not fully understood. In the present study, we attempted to elucidate the role of histamine in ghrelin-induced acid secretion in rat stomach. Intravenous administration of ghrelin at 0.8 to 20 microg/kg dose dependently increased gastric acid secretion, as measured by the gastric lumen perfusion method. The maximum response was almost equal to that of gastrin (20 microg/kg). These actions were abolished by bilateral subdiaphragmatic vagotomy. Famotidine (0.33 mg/kg) also completely inhibited the effects of ghrelin. Furthermore, ghrelin increased histidine decarboxylase (HDC) messenger RNA (mRNA) levels, as measured by real-time reverse transcription-polymerase chain reaction using LightCycler. The action of ghrelin on HDC mRNA was abolished by vagotomy. Ghrelin did not affect histamine release from isolated vascularly perfused rat stomach. Taken together, these results suggest that ghrelin stimulates gastric acid secretion via a mechanism involving activation of vagal efferent nerve and histamine release from gastric enterochromaffin-like cells.

Template switching within exons 3 and 4 of KV11.1 (HERG) gives rise to a 5' truncated cDNA

K(V)11.1 (HERG) channels contribute to membrane potential in a number of excitable cell types. We cloned a variant of K(V)11.1 from human jejunum containing a 171 bp deletion spanning exons 3 and 4. Expression of a full-length cDNA clone containing this deletion gave rise to protein that trafficked to the cell membrane and generated robust currents. The deletion occurred in a G/C-rich region and identical sequence elements of UGGUGG were located at the deletion boundaries. In recent studies these features have been implicated to cause deletions via template switching during cDNA synthesis. To examine this possibility we compared cDNAs from human brain, heart, and jejunum synthesized at lower (42 degrees C) and higher temperatures (70 degrees C). The 171 bp deletion was absent at the higher temperature. Our results suggest that the sequence and secondary structure of mRNA in the G/C rich region leads to template switching producing a cDNA product with a 171 bp deletion.

Effect of interleukin-8 on histamine release from totally isolated vascularly perfused rat stomach

BACKGROUND

Recent studies have demonstrated relationships between cytokines and gastric acid secretion. The present study was performed in rats to elucidate the effects of interleukin-8 (IL-8) on gastric acid secretion through an increase in histamine release from the stomach.

METHODS

The experiments were performed in gastric lumen-perfused rats for the study of acid secretion and in totally isolated vascularly perfused rat stomach preparations for the study of histamine release. The histamine in the effluent was determined by radioimmunoassay.

RESULTS

IL-8 (500 ng) significantly enhanced gastrin-stimulated acid secretion. IL-8, at a concentration of 500 ng/20 ml per 10 min, did not alter basal histamine release, but at 100 ng/20 ml and 500 ng/20 ml it dose-dependently increased gastrin-stimulated histamine release.

CONCLUSIONS

IL-8 enhances gastrin-stimulated acid secretion and histamine release from the rat stomach, which may explain the enhancing effect of IL-8 on gastric acid secretion.

Differential expression of P2X-purinoceptor subtypes in circular and longitudinal muscle of canine colon

Adenosine triphosphate (ATP) mediates excitatory junction potentials through P2X receptors in many smooth muscles. However, relatively little is known about postjunctional intestinal P2X receptors. We examined the effect of exogenous ATP on circular and longitudinal myocytes of canine colon using the patch clamp technique at 32 degrees C. In both cell types, ATP induced inward currents (I(ATP)) at -70 mV in a concentration-dependent manner. The potency profile of ATP analogues in circular myocytes was: ATP approximately 2-methylthio-ATP > alpha,beta-methylene ATP, and that in longitudinal myocytes was: alpha,beta-methylene ATP approximately ATP > 2-methylthio-ATP. Pretreatment of circular myocytes with alpha,beta-methylene ATP inhibited the response to subsequent ATP, suggesting receptor desensitization. I-V relationships of I(ATP) were linear with inward rectification and E(rev) of -13 mV. I(ATP) at -70 mV was carried predominantly by Na+ as determined by shifts in E(rev) when extracellular Na+ was lowered. In RT-PCR, circular myocytes expressed mRNAs encoding P2X2, 3 and 4, while longitudinal myocytes expressed mRNAs for P2X3 and 5. P2X7 was absent in both cells. Fragments of each subtype were cloned and sequenced. We failed to clone P2X1 and P2X6 genes. Overall, different P2X receptor subtypes are expressed in circular and longitudinal canine colonic myocytes. Their activation produces non-selective cation currents that can depolarize and excite muscles of both layers.

Phosphodiesterase: overview of protein structures, potential therapeutic applications and recent progress in drug development

Phosphodiesterases (PDEs) are essential regulators of cyclic nucleotide signaling with diverse physiological functions. Because of their great market potential and therapeutic importance, PDE inhibitors became recognized as important therapeutic agents in the treatment of various diseases. Currently, there are seven PDE inhibitors on the market, and the pharmacological and safety evaluations of many drug candidates are in progress. Three-dimensional (3D) structures of catalytic domains of PDE 1, -3, -4, -5 and -9 in the presence of their inhibitors are now available, and can be utilized for rational drug design. Recent advances in molecular pharmacology of PDE isoenzymes resulted in identification of new potential applications of PDE inhibitors in various therapeutic areas, including dementia, depression and schizophrenia. This review will describe the latest advances in PDE research on 3D structural studies, the potential of therapeutic applications and the development of drug candidates.

Neutrophil-derived hydroxyl radicals mediate interleukin-8-induced increases in tetragastrin-stimulated acid secretion in rats

Until recently, the secretion of gastric acid, which plays an important role in the pathogenesis of peptic ulcer, was thought to be controlled by diet, the autonomic nerves and gut hormones. However, peptic ulcer is now known to be caused by the infection with Helicobacter pylori (H. pylori), so it is possible that inflammation modifies the secretion of gastric acid. We used gastric-lumen-perfused rats to first examine the effect of interleukin-8 (IL-8) on acid secretion and then the involvement of free radicals and neutrophils in the action of IL-8. IL-8 enhanced tetragastrin-stimulated acid secretion and free radical scavengers or inhibitors and the pretreatment with anti-rat neutrophil serum inhibited this effect, which indicates that IL-8 enhances gastrin-stimulated acid secretion and that neutrophil-derived hydroxyl radicals mediate the IL-8-induced increase in acid secretion.

Expression and function of KCNH2 (HERG) in the human jejunum

Previous studies suggest that ether-a-go-go related gene (ERG) KCNH2 potassium channels contribute to the control of motility patterns in the gastrointestinal tract of animal models. The present study examines whether these results can be translated into a role in human gastrointestinal muscles. Messages for two different variants of the KCNH2 gene were detected: KCNH2 V1 human ERG (HERG) (28) and KCNH2 V2 (HERG(USO)) (13). The amount of V2 message was greater than V1 in both human jejunum and brain. The base-pair sequence that gives rise to domains S3-S5 of the channel was identical to that previously published for human KCNH2 V1 and V2. KCNH2 protein was detected immunohistochemically in circular and longitudinal smooth muscle and enteric neurons but not in interstitial cells of Cajal. In the presence of TTX (10(-6) M), atropine (10(-6) M). and l-nitroarginine (10(-4) M) human jejunal circular muscle strips contracted phasically (9 cycles/min) and generated slow waves with superimposed spikes. Low concentrations of the KCNH2 blockers E-4031 (10(-8) M) and MK-499 (3 x 10(-8) M) increased phasic contractile amplitude and the number of spikes per slow wave. The highest concentration of E-4031 (10(-6) M) produced a 10-20 mV depolarization, eliminated slow waves, and replaced phasic contractions with a small tonic contracture. E-4031 (10(-6) M) did not affect [(14)C]ACh release from enteric neurons. We conclude that KCNH2 channels play a fundamental role in the control of motility patterns in human jejunum through their ability to modulate the electrical behavior of smooth muscle cells.

Effects of interleukin-8 and Helicobacter pylori on histamine release from isolated canine gastric mucosal mast cells

BACKGROUND

In recent studies, the involvement of mast cells in the pathogenesis of Helicobacter pylori infection was suggested. In the present study, using isolated canine gastric mucosal mast cells, we undertook to elucidate the effects of interleukin-8 (IL-8) and H. pylori on histamine release from these cells.

METHODS

Enriched canine gastric mucosal mast cells (50% target cells) were incubated in Hanks medium with IL-8, or water extract or sonicate of H. pylori for 15 min at 37 degrees C. The content of histamine in the supernatants and the cell pellets after centrifugation was assayed with a histamine radioimmunoassay (RIA) kit.

RESULTS

IL-8 (50 ng/ml) and concanavalin A (20 microg/ml) significantly increased histamine release from enriched gastric mucosal mast cells. Dose-dependent stimulation of histamine release by IL-8 (5-50 ng/ml) was also seen. Water extract and sonicate of H. pylori (10(8) bacteria) increased histamine release from mast cells. A concentration-dependent stimulation of histamine release by water extract or sonicate was also seen. The maximal response of histamine release was seen at the highest concentration of the water extract or sonicate.

CONCLUSIONS

The results indicated that IL-8 and H. pylori had stimulatory effects on histamine release from canine gastric mucosal mast cells. The results imply that IL-8 and soluble factors of H. pylori may accelerate inflammation of the gastric mucosa via histamine release from mast cells.

A novel class of highly potent, selective, and non-peptidic inhibitor of Ras farnesyltransferase (FTase)

Design, synthesis and structure-activity relationship of a class of aryl pyrroles as farnesyltransferase inhibitors are described. In vitro and in vivo evaluation of a panel of these inhibitors led to identification of 2 (LB42908) as a highly potent (IC(50)=0.9 nM against H-Ras and 2.4 nM against K-Ras) antitumor agent that is currently undergoing preclinical studies.

TREK-1 regulation by nitric oxide and cGMP-dependent protein kinase. An essential role in smooth muscle inhibitory neurotransmission

Potassium channels activated by membrane stretch may contribute to maintenance of relaxation of smooth muscle cells in visceral hollow organs. Previous work has identified K(+) channels in murine colon that are activated by stretch and further regulated by NO-dependent mechanisms. We have screened murine gastrointestinal, vascular, bladder, and uterine smooth muscles for the expression of TREK and TRAAK mRNA. Although TREK-1 was expressed in many of these smooth muscles, TREK-2 was expressed only in murine antrum and pulmonary artery. TRAAK was not expressed in any smooth muscle cells tested. Whole cell currents from TREK-1 expressed in mammalian COS cells were activated by stretch, and single channel recordings showed that the stretch-dependent conductance was due to 90 pS channels. Sodium nitroprusside (10(-6) or 10(-5) m) and 8-Br-cGMP (10(-4) or 10(-3) m) increased TREK-1 currents in perforated whole cell and single channel recordings. Mutation of the PKG consensus sequence at serine 351 blocked the stimulatory effects of sodium nitroprusside and 8-Br-cGMP on open probability without affecting the inhibitory effects of 8-Br-cAMP. TREK-1 encodes a component of the stretch-activated K(+) conductance in smooth muscles and may contribute to nitrergic inhibition of gastrointestinal muscles.

3-Aryl-4-aryloyl-1-(1H-imidazol-5-yl)methylpyrrole, a novel class of farnesyltransferase inhibitors

Design, synthesis and structure-activity relationship of a class of 3-aryl-4-aryloyl-1-(1H-imidazol-5-yl)methylpyrroles as farnesyltransferase inhibitors are described. Compound 7 inhibits farnesyltransferase with an IC(50) value of 4.6 nM.

Molecular properties of small-conductance Ca2+-activated K+ channels expressed in murine colonic smooth muscle

Small-conductance Ca2+-activated K+ (SK) channels are important participants in inhibitory neurotransmission in gastrointestinal smooth muscles. Three isoforms of an SK channel family were cloned from murine proximal colon smooth muscle. The transcripts encoding these subunits (SK1, SK2, and SK3) were detected in murine proximal colon and other peripheral tissues. The mRNA of each subunit was expressed at different levels in murine and canine colonic smooth muscles. The mRNA quantitative ratio of SK transcriptional expression in murine proximal colon is SK2 > SK3 > SK1; transcriptional expression of SK isoforms in canine proximal colon is minimal. SK3 immunohistochemical localization in murine small intestine (jejunum) and proximal colon showed immunoreactivity in circular and longitudinal muscularis. In transversely sectioned muscularis, staining was localized at the cell membrane in smooth muscle cells. Immunoreactivity was more intense in myenteric ganglia between longitudinal and circular muscularis and neuronal processes in circular and longitudinal muscularis. Transient expression of mSK1, mSK2, and mSK3 in COS cells resulted in Ca2+-activated voltage-independent channels. mSK1 is less sensitive to apamin compared with SK2 and showed intracellular Ca2+ sensitivity (10(-8) to 10(-6) M) in asymmetrical K+ (5/140 mM K+) gradients. Our results suggest that SK channel expression varies in colonic myocytes from different species and may contribute differentially to inhibitory junction potentials.

Torsion angle based design of peptidomimetics: a dipeptidic template adopting beta-I turn (Ac-Aib-AzGly--NH(2))

We have attempted to design a model dipeptide (acetyl dipeptide amide, Ac-CA1-CA2--NH(2)) that can adopt specifically typical torsion angles of the beta-I turn (phi(i+1), psi(i+1), phi(i+2), psi(i+2)=-60 degrees, -30 degrees, -90 degrees, 0 degrees ). The key of the design is the combination of constrained amino acids that prefer to adopt the desired torsion angles. We chose Aib (aminoisobutyric acid) as the first residue of which phi and psi angles must be -60 degrees and -30 degrees, respectively. Then, we selected an azaamino acid as the second residue since previous studies have indicated that they prefer to adopt +/-90 degrees of phi angle and 0 degrees or 180 degrees of psi angle. The conformational preference of the resulting Ac-Aib-AzGly--NH(2) is investigated using ab initio methods. The conformations implying beta-I and beta-I' turns are energetically most favorable, as we expected. Thus, we synthesized the designed molecule on the solid phase considering the future generation of combinatorial libraries using an automatic peptide synthesizer. Then, NMR spectroscopy was carried out to confirm their conformational preference in solution was carried out. The results indicated that the Ac-Aib-AzGly--NH(2) adopt beta-I or beta-I' turns in solution forming an intramolecular hydrogen bonding between Ac--C(O) and terminal NH(2). We believe that such a small peptidomimetic template is highly useful for the design of drug candidates and molecular devices.

Novel voltage-dependent non-selective cation conductance in murine colonic myocytes

1. Two components of voltage-gated, inward currents were observed from murine colonic myocytes. One component had properties of L-type Ca(2+) currents and was inhibited by nicardipine (5 x 10(-7) M). A second component did not 'run down' during dialysis and was resistant to nicardipine (up to 10(-6) M). The nicardipine-insensitive current was activated by small depolarizations above the holding potential and reversed near 0 mV. 2. This low-voltage-activated current (I(LVA)) was resolved with step depolarizations positive to -60 mV, and the current rapidly inactivated upon sustained depolarization. The voltage of half-inactivation was -65 mV. Inactivation and activation time constants at -45 mV were 86 and 15 ms, respectively. The half-recovery time from inactivation was 98 ms at -45 mV. I(LVA) peaked at -40 mV and the current reversed at 0 mV. 3. I(LVA) was inhibited by Ni(2+) (IC(50) = 1.4 x 10(-5) M), mibefradil (10(-6) to 10(-5) M), and extracellular Ba(2+). Replacement of extracellular Na(+) with N-methyl-D-glucamine inhibited I(LVA) and shifted the reversal potential to -7 mV. Increasing extracellular Ca(2+) (5 x 10(-3) M) increased the amplitude of I(LVA) and shifted the reversal potential to +22 mV. I(LVA) was also blocked by extracellular Cs(+) (10(-4) M) and Gd(3+) (10(-6) M). 4. Warming increased the rates of activation and deactivation without affecting the amplitude of the peak current. 5. We conclude that the second component of voltage-dependent inward current in murine colonic myocytes is not a 'T-type' Ca(2+) current but rather a novel, voltage-gated non-selective cation current. Activation of this current could be important in the recovery of membrane potential following inhibitory junction potentials in gastrointestinal smooth muscle or in mediating responses to agonists.

[Drug sensitivity, conjugative R plasmids and plasmid profiles of Salmonella isolated from humans with infectious enteritis]

Using 92 Salmonella strains isolated from patients suspected of having infectious diseases of the intestinal tract who visited 13 hospitals in Japan during the six years between 1991 and 1996, we investigated the drug susceptibility, prevalence of conjugative R plasmid, and the plasmid profiles. 1) Of the bacterial isolates tested, 52.2% showed drug-resistance. Regarding the drug-resistance patterns, 70.8% of the isolates were resistant to a single drug, while 29.2% were multi drug-resistant. 2) Dividing the resistance patterns by the serotypes, among Salmonella Enteritidis isolates, single-drug resistance to SM was the most frequent, being detected in 27 isolates. Single-drug resistance to NA and two-drug resistance to SM/TC were the second-most frequent, each being detected in isolates. Among Salmonella Hadar isolates, four isolates showed two-drug resistance to SM/TC, and one isolate showed single-drug resistance to TC. Among Salmonella Typhimurium isolates, one isolate each showed three-drug resistance to ABPC/CER/KM and KM/TC/CP. Among Salmonella Agona isolates, one isolate each showed two-drug resistance to SM/TC and single-drug resistance to SM. Among Salmonella Derby isolates, two isolates showed single-drug resistance to SM. 3) The prevalence of conjugative R plasmid was investigated in 48 drug-resistant isolates, and six isolates (12.5%) contained the plasmid. 4) The prevalence of the plasmid was investigated in 29 drug-resistant S. Enteritidis isolates, and 22 isolates (75.9%) contained the plasmid. These isolated were classified by the plasmid profiles into types H1 to H7. 5) Regarding the plasmid profiles of the S. Enteritidis isolates, a position corresponding to 60 Kbp was the most frequently detected in 90.5%.

Dynamic hemicarcerands and hemicarceplexes

The reversible nature of the imine bond formation in CDCl(3) solution has been exploited to exchange substituted for unsubstituted m-phenylenediamine (MPD) units in hemicarcerand octaimines. Moreover, acid-catalyzed imine exchange has been shown to provide a novel mechanism whereby ferrocene (Fc) can be released as an entrapped guest from the hemicarceplex C(2)B(4)&crcldt;Fc dissolved in CDCl(3) to give the hemicarcerand C(2)B(4) when excess of both MPD and trifluoroacetic acid are present.

Role of azaamino acid residue in beta-turn formation and stability in designed peptide

The structural perturbation induced by C(alpha)-->N(alpha) exchange in azaamino acid-containing peptides was predicted by ab initio calculation of the 6-31G* and 3-21G* levels. The global energy-minimum conformations for model compounds, For-azaXaa-NH2 (Xaa=Gly, Ala, Leu) appeared to be the beta-turn motif with a dihedral angle of phi= +/- 90 degrees, psi=0 degrees. This suggests that incorporation of the azaXaa residue into the i+2 position of designed peptides could stabilize the beta-turn structure. The model azaLeu-containing peptide, Boc-Phe-azaLeu-Ala-OMe, which is predicted to adopt a beta-turn conformation was designed and synthesized in order to experimentally elucidate the role of the azaamino acid residue. Its structural preference in organic solvents was investigated using 1H NMR, molecular modelling and IR spectroscopy. The temperature coefficients of amide protons, the characteristic NOE patterns, the restrained molecular dynamics simulation and IR spectroscopy defined the dihedral angles [ (phi i+1, psi i+1) (phi i+2, psi i+2)] of the Phe-azaLeu fragment in the model peptide, Boc-Phe-azaLeu-Ala-OMe, as [(-59 degrees, 127 degrees) (107 degrees, -4 degrees)]. This solution conformation supports a betaII-turn structural preference in azaLeu-containing peptides as predicted by the quantum chemical calculation. Therefore, intercalation of the azaamino acid residue into the i+2 position in synthetic peptides is expected to provide a stable beta-turn formation, and this could be utilized in the design of new peptidomimetics adopting a beta-turn scaffold.

Water extract of Helicobacter pylori stimulates interleukin-8 secretion by a human gastric epithelial cell line (JR-St) through protein tyrosine phosphorylation

BACKGROUND

Infection by Helicobacter pylori induces cytokine production in gastric mucosal cells. Production of interleukin-8 (IL-8) is known to be markedly increased and is believed to play an important role in gastric mucosal inflammation. The aim of this study was to elucidate the effects of soluble factors of H. pylori on IL-8 production in a gastric epithelial cell line, JR-St.

METHODS

JR-St cells were cocultured with a H. pylori water extract, live H. pylori or culture medium supernatant for 24 h, then the IL-8 secreted into the culture medium was assayed. The effects of three different inhibitors; (i) an inhibitor of protein kinase C (PKC); (ii) an inhibitor of PKC and protein kinase A (PKA); and (iii) an inhibitor of protein tyrosine kinase (PTK) were also compared. Specific induction of IL-8 mRNA was also examined.

RESULTS

Water extract of H. pylori increased IL-8 secretion 7.72-fold, more than the control. The increase was concentration dependent. Live bacteria, supernatant and water extract significantly stimulated IL-8 secretion. Addition of live bacteria increased IL-8 secretion most strongly, while the effect of water extract was small (22% that of live bacteria). Secretion was not inhibited by the PKC inhibitor staurosporine or the inhibitors of PKA and PKC H7. However, secretion was significantly reduced by the PTK inhibitor herbimycin in a dose-dependent manner. Furthermore, 24 h exposure to water extract increased IL-8 mRNA expression, suggesting water extract increased production of IL-8.

CONCLUSIONS

Some soluble factors of H. pylori can stimulate IL-8 production by JR-St cells. Stimulation was not dependent on PKA or PKC but was, at least partially, dependent on protein tyrosine phosphorylation. This suggests that soluble factors of H. pylori can play an important role in mediating the inflammatory response of H. pylori gastritis.

Stimulatory effect of growth in the presence of alcohols on biotransformation of penicillin G into cephalosporin-type antibiotics by resting cells of Streptomyces clavuligerus NP1

Growth of Streptomyces clavuligerus NP1 in the presence of methanol or ethanol resulted in a marked increase in production of cephalosporin(s) from penicillin G by resting cells. The mycelium produced in alcohol-supplemented medium was fragmented and dispersed as compared with growth in control medium. HPLC analysis showed that at least two products were present in the biotransformation supernatant fluid after 1 h incubation. One of them has been identified as deacetoxycephalosporin G (DAOG).

Conformational studies of irreversible HIV-1 protease inhibitors containing cis-epoxide as an amide isostere

We have carried out NMR and molecular modeling studies of peptidomimetic HIV-1 protease inhibitors, LB71116: Qc-Asn-Phepsi[(1R,2S)-cis-epoxide]Gly-NH-CH(isopropyl)2 where Qc stands for quinaldic acid and LB71148: Qc-(SMe)Pen(O)2-Phepsi[(1R,2S)-cis-epoxide]Gly-NH-CH(isoprop yl)2 where (SMe)Pen(O)2 stands for S-methyl-S-dioxo-penicillamine. Through conformational calculations and NMR data analysis, we have obtained preferred conformations of the two inhibitors in solution. To our knowledge, this work is one of the first extensive conformational studies of peptidomimetics containing cis-epoxide amide isostere. The resulting preferred conformations contain extended structures. In these conformations, the psi of Phe(cep) is maintained about 130 degrees and the phi angle of (cep)Gly prefers +/- 150 degrees [where Phe(cep) and (cep)Gly are the residues generated by the replacement of the Phe-Gly peptide bond with cis-epoxide]. Two conformations were commonly observed in the preferred conformations of each inhibitor. Through restrained molecular dynamics simulating the hydrogen bond formation between our inhibitor and a water molecule ('flap water'), one of the conformations is assumed as the conformation which can bind to the enzyme without large conformational changes. Recently, we had the opportunity to compare the selected preferred conformation with the binding conformation of LB71116 observed from the X-ray studies of the complex between LB71116 and HIV-1 protease. These two conformations are surprisingly similar to each other. Thus, we can explain high activity and selectivity of our inhibitors to the HIV-1 protease by the similarity between the preferred conformations in solution and the binding conformation.

Concentrations of C-reactive protein in normal monkeys (Macaca irus) and in monkeys inoculated with Bordetella bronchiseptica R-5 and measles virus

The concentrations of C-reactive protein (CRP) in serum from normal crab-eating monkeys (Macaca irus) were measured by means of a monkey-specific turbidimetric immunoassay (TIA), and the changes in the serum CRP concentrations in crab-eating monkeys inoculated with Bordetella bronchiseptica R-5 and measles virus (Ichinose or NK 3 strain) were also examined. The CRP concentrations in sera from 54 normal crab-eating monkeys ranged from 0 to 8.3 microg/ml (mean 2.2 +/- 1.9). No significant difference was found in the CRP concentrations between males and females (p > 0.05). The concentrations of CRP in the sera from four crab-eating monkeys inoculated intrabronchially with 10(9) live B. bronchiseptica increased gradually to a peak at 2 days after inoculation. The peak concentrations of CRP were from 102.4 to 313.2 microg/ml, 54-96 times the preinoculative values of 1.9-5.6 microg/ml. When the same four crab-eating monkeys were inoculated intrabronchially with measles virus 34 days after inoculation of B. bronchiseptica, the serum CRP concentrations did not increase. Monitoring of CRP is useful for assessing monkeys with acute B. bronchiseptica infection and will probably be of value in the diagnosis of other bacterial infections.

Solid phase synthesis of azapeptides using an automatic synthesizer

Peptides containing azaglycine located terminally or within the backbone have been prepared in the solid phase by means of an automatic synthesizer.

Increased serum levels and sinusoidal expression of thrombomodulin in acute liver damage

Thrombomodulin (TM) is a surface glycoprotein of endothelial cells involved in both anticoagulation and antifibrinolysis. In this study, we assessed the clinical significance of TM in acute liver damage by using a rat model induced by intraperitoneal injection of D-galactosamine (Gal-N). Serum TM levels were measured with enzyme immunoassay utilizing rabbit anti-rat TM antibody. Simultaneously, immunohistochemical examination was performed using the same antibody. Serum TM levels increased significantly after the injection of Gal-N compared with preinjection levels, peaking from 48 to 72 hours after injection and normalizing by 168 hours. Changes in parenchymal damage were synchronized with changes of TM, and changes of TM levels mirrored changes of liver weight. In immunohistochemical examination, TM immunoreactivity was observed only on the endothelial surfaces of both the artery and portal vein within Glisson's sheath in controls. After injection of Gal-N, TM immunoreactivity was gradually intensified, especially around the necrotic area and the central veins. These findings disappeared with improvement of parenchymal damage. Both the increase of serum TM levels and intensified TM immunoreactivity in the liver were synchronized with acute liver parenchymal damage induced by Gal-N. These findings on TM are related to endothelial damage with parenchymal necrosis and liver regeneration interacting with both homeostasis of microcirculation and healing of parenchymal damage.

Interleukin-8 enhances tetragastrin-stimulated acid secretion in vivo

Recent studies have demonstrated a relationship between cytokines and gastric acid secretion. However, details of the mechanism underlying that relationship have not been elucidated. For this study, an in vivo experiment was undertaken to investigate the possibility that IL-8 would be involved in the mechanism of gastric acid secretion. Gastric lumen-perfused rats were prepared and the stomachs were perfused with a saline solution. The effluent was collected at 15-min intervals and assayed for titratable acid against 0.01 M NaOH. IL-8 (200 ng/rat) given intravenously did not influence basal acid output in rats. However, when IL-8 was administered by injection during continuous tetragastrin infusion (4 microg/kg/hr) acid output increased significantly (P < 0.01). The acid output during the first hour following IL-8 injection was 43.6% higher than prior to the injection. Acid output during the second hour was lower than during the first hour. However, successive injection of IL-8 again increased tetragastrin-stimulated acid output by 23.4% (P < 0.05). IL-8 injection did not change histamine-stimulated acid output. The results indicate that IL-8 has the effect of enhancing gastrin-stimulated acid secretion and might have an important role in the pathophysiology of gastric acid secretion in vivo.

NMR and topochemical studies of peptidomimetic HIV-I protease inhibitors containing a cis-epoxide amide isostere

NMR and topochemical studies of irreversible HIV-1 protease inhibitors containing a cis-epoxide as amide isostere have been carried out to identify conformational preference of the inhibitors in solution. The inhibitors prefer to adopt extended conformations similar to the beta-strand in solution.

Solution and solid phase combinatorial synthesis of peptidomimetic library containing diversified alpha-methylated amino acids

A combinatorial peptidomimetic library containing diversified alpha-methylated amino acids was generated by the Ugi four component condensation (4cc) reaction from acids, amines, isocyanides and ketones in both solution and solid phase synthetic procedures. This one-pot methodology overall gave fair to good yields, which compare well with multi-step syntheses.

Plasma from patients with cirrhosis increases tissue plasminogen activator release from vascular endothelial cells in vitro

AIMS/BACKGROUND

In patients with severe liver disease, blood levels of many coagulation and fibrinolytic factors are lowered due to a diminished synthetic capability in the liver. Tissue plasminogen activator (t-PA) is synthesized by the vascular endothelial cells, however, and is increased in such patients.

METHODS

Amounts of t-PA secreted were determined by immunosorbent assay after plasma from patients with cirrhosis was added to cultured human umbilical vein endothelial cells to determine whether a plasma factor directly enhanced t-PA secretion from vascular endothelial cells.

RESULTS

Release of t-PA was significantly higher with exposure to plasma from patients with decompensated cirrhosis than when plasma from patients with compensated cirrhosis or normal subjects was used (p < 0.01 and p < 0.05, respectively). Plasminogen activator inhibitor 1 (PAI-1) concentrations were measured similarly but did not differ among the three groups.

CONCLUSIONS

Our results indicate that factors in plasma from patients with decompensated cirrhosis directly stimulate t-PA release from the vascular endothelial cells, while any increased PAI-1 release observed in comparable in vivo situations is probably an indirect response to an increase of t-PA or a result of impaired hepatic clearance.

Solid phase synthesis of benzamidine and butylamine-derived hydantoin libraries

We have constructed a number of benzamidine- and butylamine-based hydantoin compounds by means of an efficient route using solid phase synthesis in which neat diisopropylamine was employed for a novel cyclization/traceless cleavage step. All library compounds were obtained in excellent yield and high purity.

Characterization of the spinal antinociceptive activity of constrained peptidomimetic opioids

We examined the in vitro and in vivo bioactivities of several families of peptidomimetic opioids including: constrained linear enkephalin (n = 12 analogs), dermorphin (n = 9 analogs) and morphiceptin (n = 17 analogs). The biological activities were assessed in vitro by examining the inhibitory effects of these agents on the electrically evoked contractions of the guinea pig ileum (GPI) and the mouse vas deferens (MVD) preparations. The in vivo bioactivities were determined from the antinociceptive activity of these agents on the 52.5 degrees C hot-plate test after spinal administration of rats with chronically placed spinal catheters. Examination of the effect of cyclization, incorporation of retro-inverso bonds and substitutions of D- or constrained amino acids reveals systematic changes in the activity of these agents. There was a significant correlation between the potency of these agents in the hot-plate bioassay and their activity in the GPI and, to a lesser extent, in the MVD tests. Examination of the ability of naltrindole (a delta selective antagonist) to reverse the drug action and the respective potency on the GPI and MVD, showed that a correlation exists with actions on the MVD, but not on the GPI, consistent with the likelihood that agents with high MVD/GPI ratios in vitro act at the mu sites, whereas those with low MVD/GPI ratios act at the delta receptor in the spinal cord. The close correlations between activity in the GPI and spinal cord suggest that the structural requirements for potency in the smooth muscle and in the spinal cord are essentially the same as those mu receptors that mediate nociceptive transmission.