[TRENDS IN DEVELOPMENT OF GI-SAFE ANTI-INFLAMMATORY DRUGS].

Despite the introduction of anti-inflammatory drugs that selectively inhibit cyclo-oxygenase-2 (COX-2), and potent inhibitors of gastric acid secretion, the gastrointestinal adverse effects of non-steroidal anti-inflammatory drugs (NSAIDs) remain a significant clinical problem. Combined use of antisecretory drugs and COX-2 inhibitors is helpful to limit the damage in the proximal gastrointestinal tract (stomach and duodenum), but it increases the risk of injury of small intestine and colon. It was proven that proton pump inhibitors and H2 receptor antagonists significantly worsen NSAID-induced small intestinal damage and microbiota balance. Nowadays, there is no proven effective preventative or curative treatment for NSAID-induced enteropathy. The new strategy of gastrointestinal protection is based on the discovery of endogenous cytoprotective molecules such as hydrogen sulfide (H2S). H2S is a gaseous mediator that produces strong cytoprotective and antioxidant effect on the gastrointestinal tract. The role of H2S in promoting mucosal integrity, healing of tissue injury and resolution of inflammation has been well documented. In addition, H2S stimulates productions of other cytoprotective molecules including prostaglandins, carbon monoxide and nitric oxide. Nowadays, the new generation of H2S-releasing non-steroidal anti-inflammatory drugs is developed and tested in clinical trials. H2S-NSAIDs possess enhanced anti-inflammatory activity and high gastrointestinal safety.

Representation of three-dimensional objects by the rat perirhinal cortex.

The perirhinal cortex (PRC) is known to play an important role in object recognition. Little is known, however, regarding the activity of PRC neurons during the presentation of stimuli that are commonly used for recognition memory tasks in rodents, that is, three-dimensional objects. Rats in the present study were exposed to three-dimensional objects while they traversed a circular track for food reward. Under some behavioral conditions, the track contained novel objects, familiar objects, or no objects. Approximately 38% of PRC neurons demonstrated "object fields" (a selective increase in firing at the location of one or more objects). Although the rats spent more time exploring the objects when they were novel compared to familiar, indicating successful recognition memory, the proportion of object fields and the firing rates of PRC neurons were not affected by the rats' previous experience with the objects. Together, these data indicate that the activity of PRC cells is powerfully affected by the presence of objects while animals navigate through an environment; but under these conditions, the firing patterns are not altered by the relative novelty of objects during successful object recognition.

Spontaneous autoimmune gastritis and hypochlorhydria are manifest in the ileitis-prone SAMP1/YitFcs mice.

SAMP1/YitFcs mice serve as a model of Crohn's disease, and we have used them to assess gastritis. Gastritis was compared in SAMP1/YitFcs, AKR, and C57BL/6 mice by histology, immunohistochemistry, and flow cytometry. Gastric acid secretion was measured in ligated stomachs, while anti-parietal cell antibodies were assayed by immunofluorescence and enzyme-linked immunosorbent spot assay. SAMP1/YitFcs mice display a corpus-dominant, chronic gastritis with multifocal aggregates of mononuclear cells consisting of T and B lymphocytes. Relatively few aggregates were observed elsewhere in the stomach. The infiltrates in the oxyntic mucosa were associated with the loss of parietal cell mass. AKR mice, the founder strain of the SAMP1/YitFcs, also have gastritis, although they do not develop ileitis. Genetic studies using SAMP1/YitFcs-C57BL/6 congenic mice showed that the genetic regions regulating ileitis had comparable effects on gastritis. The majority of the cells in the aggregates expressed the T cell marker CD3 or the B cell marker B220. Adoptive transfer of SAMP1/YitFcs CD4(+) T helper cells, with or without B cells, into immunodeficient recipients induced a pangastritis and duodenitis. SAMP1/YitFcs and AKR mice manifest hypochlorhydria and anti-parietal cell antibodies. These data suggest that common genetic factors controlling gastroenteric disease in SAMP1/YitFcs mice regulate distinct pathogenic mechanisms causing inflammation in separate sites within the digestive tract.

Proteinase-activated receptor-2 and hyperalgesia: A novel pain pathway.

Using a combined pharmacological and gene-deletion approach, we have delineated a novel mechanism of neurokinin-1 (NK-1) receptor-dependent hyperalgesia induced by proteinase-activated receptor-2 (PAR2), a G-protein-coupled receptor expressed on nociceptive primary afferent neurons. Injections into the paw of sub-inflammatory doses of PAR2 agonists in rats and mice induced a prolonged thermal and mechanical hyperalgesia and elevated spinal Fos protein expression. This hyperalgesia was markedly diminished or absent in mice lacking the NK-1 receptor, preprotachykinin-A or PAR2 genes, or in rats treated with a centrally acting cyclooxygenase inhibitor or treated by spinal cord injection of NK-1 antagonists. Here we identify a previously unrecognized nociceptive pathway with important therapeutic implications, and our results point to a direct role for proteinases and their receptors in pain transmission.

Agonists of proteinase-activated receptor 2 induce inflammation by a neurogenic mechanism.

Trypsin and mast cell tryptase cleave proteinase-activated receptor 2 and, by unknown mechanisms, induce widespread inflammation. We found that a large proportion of primary spinal afferent neurons, which express proteinase-activated receptor 2, also contain the proinflammatory neuropeptides calcitonin gene-related peptide and substance P. Trypsin and tryptase directly signal to neurons to stimulate release of these neuropeptides, which mediate inflammatory edema induced by agonists of proteinase-activated receptor 2. This new mechanism of protease-induced neurogenic inflammation may contribute to the proinflammatory effects of mast cells in human disease. Thus, tryptase inhibitors and antagonists of proteinase-activated receptor 2 may be useful anti-inflammatory agents.

Comparison of the damage-promoting effects of leukotrienes derived from eicosapentaenoic acid and arachidonic acid on the rat stomach.

The ability of leukotrienes derived from eicosapentaenoic acid were compared with counterpart leukotrienes derived from arachidonic acid in terms of their ability to affect susceptibility of the stomach to injury induced by a topical irritant and their ability to alter gastric blood flow. Intra-arterial infusion of leukotriene C4 (LTC4) and LTD4 (0.1-3 micrograms/kg/min for 5 min) produced dose-dependent increases in gastric mucosal damage induced by topically applied 20% ethanol, as assessed macroscopically, by changes in transmucosal potential difference and by measurement of efflux of protein into the gastric lumen. Similar doses of LTC5 or LTD5 did not produce significant changes in any of these three parameters, when compared with control rats receiving the vehicle. With a higher dose of LTC5 or LTD5 (5 micrograms/kg/min), significant damage was observed. LTC4 and LTD4 were also found to be more potent at reducing gastric blood flow than LTC5 and LTD5. These results demonstrate that the peptido-leukotrienes derived from eicosapentaenoic acid (LTC5 and LTD5) are on the order of five times less potent than the leukotrienes derived from arachidonic acid (LTC4 and LTD4), in terms of increasing the susceptibility of the gastric mucosa to damage and reducing gastric blood flow. These results may have important implications in terms of the hypothesis that fish oil diets may be protective or may accelerate healing in ulcerative diseases of the gastrointestinal tract.

Suppressive effects of nitric oxide-releasing prednisolone NCX-1015 on the allergic pleural eosinophil recruitment in rats.

BACKGROUND: The addition of a nitric oxide (NO)-releasing moiety to prednisolone was shown to enhance the anti-inflammatory activity of this glucocorticoid in some experimental conditions, but its effectiveness in the context of eosinophilic inflammation remains to be elucidated. OBJECTIVE: This study compared the anti-inflammatory effect of prednisolone to a NO-releasing derivative of prednisolone, NCX-1015, using a model of allergen-evoked eosinophil recruitment in rats. The efficacy of a NO-donor compound, DETA-NONOate, was also assessed for comparison. METHODS: Wistar rats were actively sensitized with Al(OH)(3) plus ovalbumin and 14 days later challenged with antigen intrapleurally. Treatments were performed locally 1 h before challenge. Cysteinyl-leucotrienes (Cys-LT) and eotaxin were measured by ELISA. RESULTS: Antigen challenge induced an eosinophil infiltration at 12 h, maximal at 24 h. It also caused an increase in the levels of Cys-LTs in the pleural exudate and in the expression of 5-lipoxygenase (5-LO) in infiltrated leucocytes at 6 h, peaking at 12 h and persisting for at least 24 h. Treatment with equimolar doses of prednisolone and NCX-1015 inhibited the late eosinophil infiltration, although the dose required to produce maximal inhibition was about one-tenth that of prednisolone. Cys-LT generation and 5-LO expression were inhibited by NCX-1015 but not by prednisolone. Treatment with prednisolone combined with the NO-donor DETA-NONOate led to a greater inhibition of the eosinophilia and Cys-LT generation as compared with either drug alone. Administration of the steroid receptor antagonist RU 486, 1 h before prednisolone and NCX-1015, abolished the inhibitory effect of the former, under conditions where it only partially affected the latter. CONCLUSIONS: Our findings indicate that NCX-1015 provided a greater anti-inflammatory effect than prednisolone on the allergic eosinophil recruitment in rats, suggesting that NO-releasing steroids can be considered as a promising therapeutic approach to allergic diseases.

Exacerbation of inflammation-associated colonic injury in rat through inhibition of cyclooxygenase-2.

Cyclooxygenase type 1 is constitutively expressed and accounts for synthesis of prostaglandins in the normal gastrointestinal tract. Cyclooxygenase-2 is expressed at sites of inflammation. Selective inhibitors of cyclooxygenase-2 have been suggested to spare gastrointestinal prostaglandin synthesis, and therefore lack the ulcerogenic effects associated with standard nonsteroidal antiinflammatory drugs. However, the effects of cyclooxygenase-2 inhibitors on inflamed gastrointestinal mucosa have not been examined. We examined cyclooxygenase-2 mRNA and protein expression before and after induction of colitis in the rat, the contribution of cyclooxygenase-2 to colonic prostaglandin synthesis during colitis and the effects of selective inhibitors of cyclooxygenase-2 on colonic injury in this model. Cyclooxygenase-2 mRNA expression increased three to sixfold during the period 24 h to 1 wk after induction of colitis, with marked increases in cyclooxygenase-2 protein expression in the lamina propria and muscularis of the colon during colitis. Cyclooxygenase-1 expression (mRNA and protein) was not affected by the induction of colitis. The prostaglandins produced during colitis were largely derived from cyclooxygenase-2. Treatment with selective cyclooxygenase-2 inhibitors resulted in exacerbation of colitis, with perforation occurring when the compounds were administered for a week. These studies demonstrate that suppression of cyclooxygenase-2 can result in exacerbation of inflammation-associated colonic injury.

Anti-thrombotic effects of a nitric oxide-releasing, gastric-sparing aspirin derivative.

Effects of a nitroxybutylester derivative of aspirin (NCX 4215) on platelet aggregation and prostanoid synthesis were compared to the effects of aspirin. NCX 4215 was approximately seven times more potent than aspirin as an inhibitor of thrombin-induced human platelet aggregation in vitro, but did not inhibit platelet thromboxane synthesis or gastric prostaglandin synthesis. NCX 4215 released nitric oxide when incubated in the presence of platelets and increased platelet levels of cGMP within 10 min of exposure, while aspirin did not. The anti-aggregatory effects of NCX 4215 in vitro were significantly attenuated by 10 microM hemoglobin. In ex vivo studies of ADP- or collagen- or thrombin-induced rat platelet aggregation, aspirin and NCX 4215 had comparable inhibitory effects 3 h after administration. Aspirin (10-120 mg/kg) caused extensive hemorrhagic erosion formation in the stomach of the rat within 3 h of oral administration, while NCX 4215 did not produce significant damage at doses of up to 300 mg/kg, nor when given daily for two weeks at 166 mg/kg. NCX 4215 did not alter systemic arterial blood pressure when administered intravenously to the rat. These studies demonstrate that NCX 4215 has comparable or enhanced anti-thrombotic activity to that of aspirin, but does not cause gastric damage or alter systemic blood pressure. The anti-thrombotic actions of NCX 4215 are, at least in part, due to generation of nitric oxide.

Building a better aspirin: gaseous solutions to a century-old problem.

The gastrointestinal adverse effects of nonsteroidal anti-inflammatory drugs (NSAIDs) have been recognized since shortly after the introduction of aspirin to the marketplace over a century ago. However, the underlying pathogenesis of NSAID-induced gastropathy remains incompletely understood. Advances in understanding some of the factors that contribute to the mucosal injury have provided clues for the development of safer NSAIDs. The inhibitory effects of nitric oxide (NO) on NSAID-induced leukocyte adherence were exploited in the development of NO-releasing NSAIDs. As well as eliciting less gastrointestinal damage than conventional NSAIDs, these drugs do not elevate blood pressure and show anti-inflammatory effects, additional to those of the parent drugs. Modification of other drugs in a similar manner (i.e., NO-releasing derivatives) has similarly resulted in more effective drugs. More recently, hydrogen sulphide-releasing derivatives of NSAIDs and of other drugs, have been developed, based on the observed ability of H(2)S to reduce inflammation and pain in experimental models. H(2)S-releasing NSAIDs produce negligible gastric damage and exhibit enhanced anti-inflammatory potency as compared to the parent drugs. The NO-NSAIDs and H(2)S-releasing NSAIDs represent examples of new anti-inflammatory drugs with greatly reduced toxicity and improved therapeutic activity, both created through the concept of exploiting the beneficial effects of endogenous gaseous mediators.

Mechanisms underlying the anti-inflammatory activity and gastric safety of acemetacin.

BACKGROUND AND PURPOSE: Acemetacin is regarded as a pro-drug of indomethacin and induces significantly less gastric damage but the reasons for this greater gastric safety of acemetacin are unclear. The anti-inflammatory effects of acemetacin have been attributed, at least in part, to its hepatic biotransformation to indomethacin. The aim of this study was to determine the effects of acemetacin and indomethacin in an in vivo model of acute inflammation and to examine the importance of biotransformation of acemetacin (to indomethacin) to its anti-inflammatory actions. EXPERIMENTAL APPROACH: The zymosan airpouch model was used in rats. Indomethacin or acemetacin (2.7-83.8 micromol kg(-1)) were administered orally or directly into the pouch. Leukocyte infiltration, prostaglandin (PG) E(2) and leukotriene (LT) B(4) levels in exudates, and whole blood thromboxane (TX) B(2) synthesis were measured. KEY RESULTS: Acemetacin was rapidly converted to indomethacin after its administration. Both acemetacin and indomethacin elicited comparable, dose-dependent reductions of leukocyte infiltration and of PGE(2) and TXB(2) synthesis. However, indomethacin induced more gastric damage than acemetacin and elevated LTB(4) production in the airpouch. CONCLUSIONS AND IMPLICATIONS: The similar effects of acemetacin and indomethacin on leukocyte infiltration and PG synthesis are consistent with rapid biotransformation of acemetacin to indomethacin. Some of this biotransformation may occur extra-hepatically, for instance in inflammatory exudates. Acemetacin probably exerts actions independent of conversion to indomethacin, given the different effects of these two drugs on LTB(4) production. Such differences may contribute to the relative gastric safety of acemetacin compared to indomethacin.

Enhanced activity of a hydrogen sulphide-releasing derivative of mesalamine (ATB-429) in a mouse model of colitis.

BACKGROUND AND PURPOSE: Mesalamine is the first-line therapy for colitis, but it lacks potency and is only effective for mild-to-moderate forms of this disease. Hydrogen sulphide has been shown to be a potent, endogenous anti-inflammatory substance, modulating leukocyte-endothelial adhesion and leukocyte migration. The purpose of this study was to determine if an H(2)S-releasing derivative of mesalamine (ATB-429) would exhibit increased potency and effectiveness in a mouse model of colitis. EXPERIMENTAL APPROACH: Colitis was induced in mice with trinitrobenzene sulphonic acid and the effects of ATB-429 and mesalamine were compared in several treatment regimens. The severity of colitis was determined using several indices, including a disease activity score (comprised of scores for diarrhea, weight loss and fecal blood), colonic myeloperoxidase activity and macroscopic/microscopic scoring of tissue injury. KEY RESULTS: Irrespective of the treatment regiment, ATB-429 was more effective than mesalamine in reducing the severity of colitis. ATB-429 was particularly effective in reducing granulocyte infiltration into the colonic tissue (by approximately 70%), as well as reducing the expression of mRNA for several key proinflammatory cytokines/chemokines (e.g., TNFalpha, IFNgamma). Treatment with ADT-OH, the H(2)S-releasing moiety of ATB-429, did not affect severity of colitis. CONCLUSIONS AND IMPLICATIONS: ATB-429 exhibits a marked increase in anti-inflammatory activity and potency in a murine model of colitis, as compared to mesalamine. These results are consistent with recently described anti-inflammatory effects of H(2)S. ATB-429 may represent an attractive alternative to mesalamine for the treatment of inflammatory bowel disease.

The effect of hydrogen sulfide-releasing naproxen (ATB-346) versus naproxen on formation of stress-induced gastric lesions, the regulation of systemic inflammation, hypoxia and alterations in gastric microcirculation.

Clinical use of non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin or naproxen is limited due to the gastrotoxicity evoked by these compounds. Endogenous hydrogen sulfide (H2s) and delivered via an H2s donor have been shown to play important role in the maintenance of gastric mucosal integrity. This study aimed to compare the effects of naproxen and an H2s-releasing naproxen derivative (ATB-346) on gastric lesion induction by water immersion and restraint stress (WRS), the alterations in gastric blood flow (GBF) and the influence of these drugs on systemic inflammation. Wistar rats were pretreated i.g. with vehicle, naproxen (20 mg/kg) or ATB-346 (equimolar dose) or NaHS (5 mg/kg), the H2s donor, combined with naproxen and exposed to 3.5 hours of WRS. The gastric lesion number and GBF were assessed by planimetry and laser Doppler flowmetry, respectively. Plasma concentrations of interleukins: IL-1α, IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) and GM-CSF were determined by Luminex system and gastric mucosal protein expression of cystathionine-γ-lyase (CSE), cystathionine-ß-synthase (CBS), 3-mercaptopyruvate sulfurtransferase (3-MST), nuclear factor (erythroid-derived 2)-like 2 (Nrf-2), hypoxia inducible factor-1α (HIF-1α), heme oxygenase-1 (HO-1) and cyclooxygenase (COX-2) were analyzed by Western blot. Pretreatment with naproxen increased the number of WRS stress-induced gastric lesions and significantly decreased GBF as compared with vehicle (p < 0.05). In contrast, pretreatment with ATB-346 or naproxen combined with NaHS significantly reduced WRS-lesions number and elevated GBF as compared with naproxen (p < 0.05). Naproxen significantly increased gastric mucosal protein expression of CSE, Nrf-2 and HIF-1α as compared with vehicle (p < 0.05), but failed to affect CBS, 3-MST and HO-1. ATB-346 significantly increased Nrf-2 and HO-1 protein expression as compared with vehicle (P < 0.05) but did not affect the protein expression of CSE, CBS, 3-MST or HIF-1α. ATB-346 but not naproxen decreased COX-2 protein expression in gastric mucosa compromised by WRS (p < 0.05). Exposure to WRS increased plasma concentration of all investigated cytokines (p < 0.05). ATB-346 but not naproxen decreased plasma content of IL-1α, IL-4, IL-5, IL-6, IL-10, IL-12, TNF-α and IFN-γ in rats exposed to WRS (p < 0.05). We conclude that H2s through its vasoactive properties attenuates the gastrotoxic effects of naproxen, which increased stress-induced hypoxia in gastric mucosa. In contrast to naproxen, ATB-346 decreased stress-induced systemic inflammation and pro-inflammatory COX-2 expression in the gastric mucosa. The decreased gastrotoxicity of ATB-346 could be due to upregulation of Nrf-2/HO-1 pathway mediated by the release of H2s.

Glyprolines exert protective and repair-promoting effects in the rat stomach: potential role of the cytokine GRO/CINC-1.

Glyprolines have been reported to exert protective effects in the stomach. In this study, we examined the potential effects of intranasal administration of Pro-Gly-Pro (PGP) and N-acetyl-Pro-Gly-Pro (AcPGP) on experimental gastric ulcer formation and healing. We also studied gastric release of the cytokine GRO/CINC-1, and its potential role in ulcer development and healing. Gastric ulcers were induced in rats by applying acetic acid to the serosa of the stomach. PGP and AcPGP were then administered at a dose of 3.7 µmol/kg once daily on either days 1 - 3 (ulcer formation) or days 4 - 6 (ulcer healing). Measurement of ulcer area and histological examination of gastric tissue were carried out on days 4 and 7 after application of acetic acid. In vitro studies involved addition of the glyprolines to cultured rat gastric epithelial cells with or without lipopolysaccharide. Reverse transcription PCR, real-time PCR and ELISA were used for cytokine analysis. PGP and AcPGP significantly reduced ulcer areas on the 4(th) day and accelerated the healing on the 7(th) day compared with the control. After acetic acid-induced ulceration, the expression of GRO/CINC-1 mRNA in gastric tissue was increased 9-fold versus the sham-operated group. Treatment with PGP or AcPGP both significantly suppressed the expression of GRO/CINC-1 mRNA in gastric tissue. However, the glyprolines did not alter LPS-induced mRNA expression or release of GRO/CINC-1 from cultured rat gastric epithelial cells, even though those cells were harvested from rats subjected to the ulcer-induction procedure. The results of this study show that intranasal administration of PGP and AcPGP significantly increased resistance against acetic acid-induced ulceration and accelerated healing in the rats. These effects may be due, at least in part, to their ability to reduce the acetic acid-induced GRO/CINC-1 expression and production in gastric tissue.

Capsaicin effects on non-neuronal plasma membranes.

Capsaicin has been touted as a pharmacological tool specific for sensory afferent neurons and is widely used in neurophysiological studies. However, we have recently demonstrated that in concentrations commonly employed within the gastrointestinal tract, capsaicin inhibits platelet aggregation to at least three different stimuli. Since this was observed in a nerve free system it raised the question of how specific capsaicin is. In this communication we report that capsaicin has profound effects on physical properties of non-neuronal cell plasma membranes. These effects were observed while measuring the effect of capsaicin upon the fluidity of both intact cell membranes and a variety of purified membrane preparations. Membrane fluidity was assessed with the fluorescent probes diphenylhexatriene (DPH) and its trimethylamino derivative TMA-DPH and demonstrated concentration-dependent capsaicin effects. Furthermore, the effects were cell specific and for full expression required both intact cells and a non-lipid extractable component of the plasma membrane. These non-neuronal effects must be carefully considered when contemplating the explanation for capsaicin-induced effects.

Protease-activated receptors in inflammation, neuronal signaling and pain.

The ability of proteases to regulate cell function via protease-activated receptors (PARs) has led to new insights about the potential physiological functions of these enzymes. Several studies suggest that PARs play roles in both inflammation and tissue repair, depending on the cellular environment in which they act. The recent detection of PARs on peripheral and central neurons suggests that neuronal PARs might be involved not only in neurogenic inflammation and neurodegenerative processes, but also in nociception. Thus, the list of potential roles for PARs has lengthened considerably and their physiological course of action might be much broader than initially anticipated.

Can insights into urodele limb regeneration be achieved with cell cultures and retroviruses?

Recent advances in the field of amphibian limb regeneration have provided insights into its cellular and molecular events. This review summarizes the development of cell lines from limb tissues and their application to the study of transdifferentiation and limb regeneration. In addition, the availability of suitable retroviral vectors for salamanders is discussed for it has opened new avenues for experimentation at the molecular level.

Inhibition of neurogenic inflammation by the Amazonian herbal medicine sangre de grado.

UNLABELLED: This study was designed to determine if the Amazonian medicinal sangre de grado, confers benefit by suppressing the activation of sensory afferent nerves. METHODS: (i) vasorelaxation of rat mesenteric arteries in response to calcitonin gene-related peptide; (ii) rat paw edema in response to protease- activating peptide receptor 2-activating peptide; (iii) rat paw hyperalgesia in response to low-dose protease-activating peptide receptor 2-activating peptide or prostaglandin E2; (iv) gastric hyperemia in response luminal capsaicin; (v) a clinical trial of a sangre de grado balm in pest control workers. The parent botanical was fractionated for evaluation of potential active components. In preconstricted rat mesenteric arteries, highly diluted sangre de grado (1:10,000) caused a shift to the right of the calcitonin gene-related peptide dose-response curve (p < 0.01). Paw edema in response to protease-activating peptide receptor 2-activating peptide (500 microg) was reduced by as single topical administration sangre de grado balm (1% concentration, p < 0.01) for at least 6 h. Hyperalgesia induced by either low-dose protease-activating peptide receptor 2-activating peptide (50 microg) or prostaglandin E2 was prevented by sangre de grado balm. A fraction possessing analgesic and capsaicin antagonistic properties was isolated and high-performance liquid chromatography and gas chromatography-mass spectrometry analysis indicated that it was a proanthocyandin oligomer. In pest control workers, sangre de grado balm (Zangrado) was preferred over placebo, for the relief of itching, pain, discomfort, edema, and redness in response to wasps, fire ants, mosquitoes, bees, cuts, abrasions, and plant reactions. Subjects reported relief within minutes. We conclude that sangre de grado is a potent inhibitor of sensory afferent nerve mechanisms and supports its ethnomedical use for disorders characterized by neurogenic inflammation.

Cloning of homoeobox sequences expressed in the intact and the regenerating newt eye.

In this report we present the sequences of four different homeoboxes cloned from the intact and regenerating eye of the newt Notophthalmus viridescens. All these homeoboxes are novel for this species.

Nonsteroidal anti-inflammatory drugs and the gastrointestinal tract. Mechanisms of protection and healing: current knowledge and future research.

The resistance of the gastric mucosa to injury is attributable to a series of factors collectively known as "mucosal defense." Many components of mucosal defense are regulated by prostaglandins and nitric oxide (NO). Thus, inhibition of the production of these mediators predisposes the stomach to injury. Administration of these agents, as synthetic prostaglandins or NO donors, can restore mucosal defense and thereby prevent damage induced by several irritants. Repair of gastric ulcers is also influenced by NO and prostaglandins. Furthermore, a variety of growth factors appear to play critical roles in stimulating the formation of granulation tissue (the "foundation" for repair), the formation of new blood vessels, and the proliferation of epithelial cells. Better understanding of the factors that regulate ulcer healing should provide clues for the development of drugs that can produce better "quality" healing of ulcers.