Prostaglandin (PG) has been reported to be an important protective and acid-suppressive factor in the gastric mucosa. Although the mechanisms of some antiulcer drugs are attributed to their stimulatory effects on endogenous prostaglandins, an understanding of these actions has not been established. In the present study we investigated the effects of antiulcer drugs on PGE2 using cultured gastric mucosal cells. Rabbit gastric mucosal cells were cultured after isolation with collagenase and ethylenediaminetetraacetic acid. PGE2 was measured by enzyme-linked immunoassay. Histamine H2-blockers (cimetidine, ranitidine, famotidine), omeprazole, and sucralfate did not modulate the media content of PGE2, whereas sofalcone dose- and time-dependently increased it. Sofalcone-induced increase of PGE2 was dose-dependently prevented by indomethacin. Sofalcone did not affect intracellular Ca2+ as assessed by the calcium-sensitive probe indo-1. Deprivation of Ca2+ in the media did not modulate the action of sofalcone. Sofalcone significantly suppressed 15-OH-PG dehydrogenase. These results suggest that among the various antiulcer drugs only sofalcone increases PGE2, which may be a factor in its therapeutic effect against peptic ulcer diseases.

Gastric ulcers were produced in conscious cats in 3 hr by simultaneous intravenous or intragastric administration of acetylsalicylic acid (ASA), plus intravenous infusion of histamine (80 micrograms/kg/hr), pentagastrin (8 micrograms/kg/hr), or intragastric instillation of HCl. The formation of these ulcers was accompanied by almost complete inhibition of prostaglandin (PG) biosynthesis, suggesting that the withdrawal of normal protection of gastric mucosa by PGs may be major factor in pathogenesis of ASA-induced gastric lesions. Prostacyclin (PGI2), infused at a dose producing about 50% inhibition of histamine or pentagastrin-induced acid secretion, significantly reduced the formation of gastric ulcers produced by ASA + histamine or pentagastrin. Inhibition of gastric acid secretion by about 50% using ranitidine, a new H2-receptor antagonist, also decreased the formation of gastric ulcers induced by ASA + gastric secretagogue, but the degree of this reduction was significantly smaller than after PGI2. In addition, PGI2 decreased significantly the severity of gastric ulcers produced by a combination of ASA plus gastric perfusion of HCl, the antiulcer effect being more pronounced when PGI2 infusion was started prior to, rather than during, ASA administration. This study confirms that the administration of ASA plus gastric secretagogue or gastric instillation of HCl is a reliable model of gastric ulcerations probably resulting from withdrawal of biosynthesis of mucosal PGs and shows that PGI2 is capable of preventing the formation of these ulcers by means other than its effect on gastric acid secretion.

Because of their desirable characteristics, for example small size, lightness, low power and gas consumption, and potential for portability, miniaturized plasma sources are receiving significant attention in the scientific literature. To take advantage of these characteristics we micromachined and fabricated new, planar-geometry, self-igniting, atmospheric-pressure microplasma devices (MPDs) on chips. These microplasmas required such low power for their operation they could be operated from a re-chargeable battery (of the type used in cordless power-tools). Despite their advantages, most miniaturized plasma sources reported in the literature have not performed well with liquid samples; analysis of powders or solids that can be converted to a powder (and processed and used as slurries) is even more difficult. To address these shortcomings we coupled an electrothermal, mini-in-torch vaporization (mini-ITV) "dry" sample-introduction system to the low-power planar microplasma devices we developed. In this preliminary investigation, absolute detection limits obtained from microsamples of single-element liquid standards and optical emission spectrometry with photomultiplier-tube detection and a spectral bandpass similar to that of portable, commercially available fiber-optic spectrometers were in the low-pg to ng range, for example 2 pg (for K) to 25 ng (for Pb). Mini-ITV also enabled (as far as we are aware, for the first time) measurement of analyte emission from microsamples of powdered solids (as slurries). In addition to the 3% H2 in Ar mixtures, the ac-operated microplasmas were sustained by use of a variety of electrode materials and different plasma-support gases (e.g. Ar, He and 3% H2 in He) thus indicating fabrication versatility and operational flexibility. Such flexibility has the potential to enable microplasmas to be tailored to analytical problems, and this is demonstrated by using a He MPD and chlorine emission measurements (837.594 nm) from gaseous microsamples as an example.

We have applied a new chemical reaction interface/mass spectrometer technique (CRIMS) to the selective detection of 13C-, 15N-, and 2H-labeled phenytoin and its metabolites in urine following separation by capillary gas chromatography. The microwave-powered chemical reaction interface converts materials from their original forms into small molecules whose mass spectra serve to identify and quantify the nuclides that make up each analyte. The presence of each element is followed by monitoring the isotopic variants of CO2, NO, or H2 that are produced by the chemical reaction interface. Chromatograms showing only enriched 13C and 15N were produced by subtracting the abundance of naturally occurring isotopes from the observed M + 1 signal. A selective chromatogram of 2H (D) was obtained by measuring HD at m/z 3.0219 with a resolution of 2000. Metabolites representing less than 1.5% of the total labeled compounds could be identified in the chromatogram. Detection limits from urine of 380 pg/mL of a 15N-labeled metabolite, 7 ng/mL of a 13C-labeled metabolite, and 16 ng/mL of a deuterium labeled metabolite were determined at a signal to noise ratio of 2. Depending on the isotope examined, a linear dynamic range of 250-1000 was observed using CRIMS. To identify many of these labeled peaks (metabolites), the chromatographic analysis was repeated with the chemical reaction interface turned off and mass spectra obtained at the retention times found in the CRIMS experiment. CRIMS is a new analytical method that appears to be particularly useful for metabolism studies.

BACKGROUND

A randomized prospective study on the response of fasting serum gastrin concentrations in peptic ulcer patients was performed in order to test the hypothesis that H. pylori infection in the gastric antrum increases gastrin release, and to examine whether the high fasting serum gastrin concentrations respond to treatment that eradicates H. pylori.

METHODS

One hundred and twenty-seven patients with gastric or duodenal ulcer were included in this study. Patients were divided into three groups on the basis of antral H. pylori status and therapeutic modalities. The first group, 58 patients infected by H. pylori, was treated with metronidazole and tripotassium dicitrato bismuthate combined with ranitidine and mylanta. The second group, 40 patients also infected by H. Pylori, was treated with ranitidine and mylanta. The third group, 29 patients, free of H. pylori infection, was designed to evaluate the influence of H2-receptor antagonist on the change of gastrin. When ulcers were completely healed, changes of gastrin concentrations and H. pylori status were re-examined.

RESULTS

H. pylori was eradicated in all patients who have received antibacterial therapy in 4 weeks, and serum gastrin concentrations were significantly decreased after eradication of the organism both in gastric and in duodenal ulcer diseases. (Gastric ulcer: 129.3 +/- 47.0 pg/ml before and 63.7 +/- 21.6 pg/ml after treatment. Duodenal ulcer: 108.3 +/- 35.0 pg/ml and 66.5 +/- 21.9 pg/ml, respectively. Total: 112.7 +/- 38.2 pg/ml vs 66.0 +/- 21.6 pg/ml) (p < 0.01). In contrast, H. pylori-positive patients who have not received antibacterial therapy were still infected at the completion of the study, and serum gastrin concentrations increased even though the difference was not significant. (Gastric ulcer: 118.4 +/- 51.2 pg/ml vs 124.0 +/- 56.5 pg/ml. Duodenal ulcer: 85.4 +/- 35.1 pg/ml vs 104.6 +/- 43.5. Total: 99.5 +/- 45.3 vs 112.9 +/- 48.7 pg/ml.) (p>> 0.05). None of the patients who were initially H. pylori-negative has been reinfected during the period of the study, and their serum gastrin concentrations were not changed. (Gastric ulcer: 69.8 +/- 38.0 pg/ml. Total: 63.2 +/- 31.1 pg/ml. Duodenal ulcer: 55.1 +/- 17.6 pg/ml vs 55.8 +/- 13.8 pg/ml. Total: 63.2 +/- 31.1 pg/ml vs 63.4 +/- 30.0 pg/ml). Four- to six-week therapy of H2-receptor antagonist and antacid had no influence on serum gastrin concentrations.

CONCLUSIONS

On the basis of the above results, we confirmed that the chronic infection of H. pylori of gastric antrum in peptic ulcer patients causes increased release of serum gastrin, and eradication of the organism results in a significant fall in serum gastrin concentrations.

Prostaglandin (PG) D2 has been postulated to be an endogenous sleep-promoting factor. Biosynthesis of PGD2 is catalyzed by PGD synthase (prostaglandin-H2 D-isomerase, EC 5.3.99.2), the activity of which is inhibited by inorganic selenium compounds such as SeCl4 and Na2SeO3. We recently examined the effect of intracerebroventricular administration of these selenium compounds on sleep in rats, and demonstrated time- and dose-dependent sleep inhibition. To establish whether this effect of selenium is also produced when the compound is administered systemically, we devised a procedure for intravenous catheterization and examined the effect of these selenocompounds on sleep-wake activity in freely moving rats (n = 35). Each test compound was administered into the inferior vena cava continuously between 11.00 and 17.00 h on the experimental day. SeCl4 time- and dose-dependently inhibited sleep at infusion rates of 5, 7.5, 10 and 20 nmol/microliters per min. During the SeCl4 infusion at 20 nmol/microliters per min, slow-wave sleep and paradoxical sleep were reduced to 63% and 50% of their respective baseline values. Na2SeO3 exhibited a similar sleep inhibition, though Na2SO3 was ineffective. Infusion of SeCl4 at 10 nmol/microliters per min or below produced no consistent changes in the mean brain temperature, or food and water intake during the infusion period. During the nocturnal period subsequent to SeCl4 infusion, sleep was increased by a rebound phenomenon, while a decrease in brain temperature and inhibition of food and water intake dose-dependently occurred. We conclude that systemic administration of these PGD synthase inhibitors has a sleep-reducing potency.

Desensitization of platelet thromboxane (TX)A2/prostaglandin (PG)H2 receptors was induced by incubating platelet-rich plasma with the stable PGH2 analog 11 alpha,9 alpha-(epoxymethano)prosta-5Z,13E-dienoic acid (U46619) (1 microM). Iloprost, a stable prostacyclin analog, was included in the incubation to prevent platelet activation. The TXA2 mimetic, [1S-1 alpha,2 beta(5Z), 3 alpha(1E,3S*), 4 alpha)]-7-[3-(3-hydroxy-4-(4'-iodophenoxy)-1-butenyl)-7-oxabicyclo - [2.2.1]heptan-2-yl]-5-heptenoic acid (I-BOP), was used to induce platelet aggregation, shape change and increases in intracellular free calcium. The EC50 values for I-BOP-induced rise in intracellular free calcium (control = 10.2 +/- 1.5 nM; desensitized = 79.4 +/- 22.4 nM, n = 6, P less than .05), aggregation (control = 15.8 +/- 2.4 nM; desensitized = 51.7 +/- 11.9 nM; P less than .05, n = 5) and shape change (control = 172 +/- 37 pM; desensitized = 350 +/- 60 pM; P less than .05, n = 7) were increased by the preincubation with U46619. Aggregation responses to thrombin and the calcium ionophore, ionomycin, were unaltered by the preincubation with U46619. Equilibrium binding studies at pH 7.4 revealed a decrease in the number of binding sites for the receptor antagonist 9,11-dimethylmethano-11,12- methano-16(3-iodo-4-hydroxyphenyl)-13,14-dihydro-13-aza-15 alpha beta-omega- tetranor-TXA2 [125I]PTA-OH) (control = 3246 +/- 509 sites/platelet, desensitized = 2198 +/- 324 sites/platelet, n = 6, P less than .05) without a change in affinity.(ABSTRACT TRUNCATED AT 250 WORDS)

We evaluated the effects of histamine receptor antagonists on the renal vasodilatory responses to ureteral occlusion (UO), to the intrarenal infusion of prostaglandins E2, I2, A2, D2 and E1, and to bradykinin. We also determined the effects of meclofenamic acid, a cyclooxygenase inhibitor, on histamine-induced renal vasodilation and the effects of 2-methylhistamine (2-MeH), and H1 agonist, on glomerular filtration rate (GFR) and renal blood flow (RBF). Experiments were performed on adult mongrel dogs anesthetized with pentobarbital sodium. RBF was measured with an electromagnetic flow probe. Neither UO-induced nor prostaglandin- (PG) induced renal vasodilation was affected by infusion of the histamine H2 receptor antagonist cimetidine into the renal artery at 10(-5) M/min. On the other hand, renal artery infusion of the H1 receptor antagonist chlorpheniramine (CP) at 10(-5) M/min blocked UO-induced renal vasodilation [RBF increased 34 +/- 4% (SE) prior to but only 2 +/- 2% during infusion of CP) and markedly attenuated PGI2-, PGA2-, and PGE2-induced increases in RBF (CP inhibited 64 +/- 9% of the PGE2-induced renal vasodilation). CP had less effect on the renal vasodilation associated with infusion of PGD2 or PGE1 and had no effect on the vasodilation induced by bradykinin. Infusion of exogenous histamine (1 micrograms X kg-1 X min-1) into the renal artery prior to ureteral occlusion resulted in a typical H1 + H2-mediated vasodilatory response (RBF increased 53 +/- 7%).(ABSTRACT TRUNCATED AT 250 WORDS)

The vasorelaxant effects of pituitary adenylate cyclase activating polypeptide (PACAP)-27 were examined and compared with those of PACAP-38 and vasoactive intestinal polypeptide (VIP) on isolated canine cerebral arteries and rat intracerebral arterioles in vitro. The addition of PACAP-27, PACAP-38 or VIP resulted in similar concentration-dependent relaxations in both canine basilar arteries and rat intracerebral arterioles. There were regional differences in the PACAP-27-induced relaxations measured in canine cerebral arteries. The maximum relaxation induced by PACAP-27 was significantly lower in the basilar arteries (23.0 +/- 5.6%) than in the rostrally located arteries (proximal middle cerebral arteries: 45.4 +/- 5.7%, anterior cerebral arteries: 55.2 +/- 5.8%). The maximum relaxation induced by PACAP-27 in the basilar arteries was significantly enhanced by mechanical removal of the endothelium (16.4 +/- 4.5% vs. 32.7 +/- 5.8%) as well as by pretreatment with indomethacin or aspirin (12.9 +/- 4.1% vs. 48.7 +/- 6.1% and 46.5 +/- 9.2%, respectively). Incubation of canine cerebral arteries with PACAP-27 in vitro resulted in an increased release of prostaglandin F2 alpha in the buffer from 14.5 +/- 2.1 pg/min/1 mg vessel to 31.1 +/- 4.2 pg/min/1 mg vessel, while other cyclooxygenase cascade metabolites such as prostaglandin E2, thromboxane B2 and 6-keto prostaglandin F1 alpha did not change. These data suggest that the PACAP-27-induced relaxation of canine basilar arteries may be associated with prostaglandin F2 alpha or its precursor, prostaglandin H2.

BACKGROUND

Cytokines from inflammatory cells do not produce nitric oxide, but stimulate the production of nitric oxide in vascular smooth muscle cells (VSMC). Thromboxane A2 (TXA2) has been believed to have a key role in atherosclerogenesis and post-angioplasty restenosis.

OBJECTIVE

To determine whether cytokine-induced nitric oxide production is regulated by the TXA2/prostaglandin H2 (PGH2) receptor.

RESULTS

We studied the interleukin-1beta (IL-1beta)-induced production of nitric oxide in rat VSMCs using the TXA2/PGH2 receptor antagonists, seratrodast and Bay-u3405, and an agonist, U-46619. Nitrite formation was measured colorimetrically. IL-1beta increased nitrite formation in a time-dependent manner. The nitrite concentration was 1.7 times greater in the presence of seratrodast than that without it. Nitrite accumulation was increased by Bay-u3405, but was decreased in the presence of U-46619, to 44% of that in its absence. Western and Northern blotting showed that seratrodast increased the levels of expression of inducible nitric oxide synthase (iNOS) protein and mRNA in a dose-dependent manner, whereas U-46619 decreased them. We speculated that VSMCs produced TXA2, thereby decreasing nitric oxide production; therefore we measured the accumulation of TXB2 using an enzyme immunoassay. Untreated VSMCs produced about 20 pg/mg protein of TXB2. This was increased by the addition of IL-1beta, to 152.1 +/- 43.0 pg/mg protein after a 24 h incubation; the expression of cyclooxygenase-2 (COX-2) protein was also increased, but there was no effect on the expression of COX-1 and TXA2 synthase. U-63557A, a TXA2 synthase inhibitor, increased the accumulation of nitrite to 1.3-fold that in its absence.

CONCLUSIONS

These data suggest that the expression of iNOS and the production of nitric oxide are regulated by the TXA2/PGH2 receptor in IL-1beta-stimulated VSMCs. The endogenous production of TXA2 by the induction of COX-2 from IL-1beta-stimulated VSMCs probably downregulated the production of nitric oxide in VSMCs. TXA2/PGH2 receptor inhibitors may contribute to the reduction in formation of atherosclerosis in lesions with vascular injury by enhancing the production of nitric oxide by VSMCs.

The antioxidizing properties of curcumin, a highly pleiotropic substance used for centuries in traditional medicine has been confirmed by numerous experimental and clinical studies. Curcumin exhibits anti-inflammatory, antiproliferative and anti-angiogenic actions inhibiting the development and progression of tumors but the efficacy of this compound to influence gastric acid secretion n in the stomach and to affect the gastric mucosal damage induced by non-topical ulcerogenes such as stress has been little studied. We determined the effect of curcumin on basal and pentagastrin- or histamine-stimulated gastric secretion, in rats with surgically implemented gastric fistulas and we assessed the contribution of gastric secretion, endogenous prostaglandin (PG), endogenous nitric oxide (NO), as well as sensory afferent nerves in the mechanisms underlying the potential gastroprotective effects of curcumin against stress-induced gastric mucosal lesions. Rats exposed to water immersion and restraint stress (WRS) for 3.5 h were pretreated either with: 1) vehicle (saline); 2) curcumin (2.5 - 100 mg/kg i.g.) or 3) curcumin (50 mg/kg i.g.) combined with or without indomethacin (5 mg/kg i.p.), SC-560 (5 mg/kg i.g.) or rofecoxib (10 mg/kg i.g.); 4) curcumin (50 mg/kg i.g.) co-administered with (L-NNA (20 mg/kg i.p.) with or without L-arginine (200 mg/kg i.g.), a substrate for NO-synthase; 5) curcumin (50 mg/kg i.g.) administered in rats with intact or capsaicin-induced functional ablation of sensory nerve fibers, and 6) curcumin (50 mg/kg i.g.) administered with capsazepine (5 mg/kg i.g.), the antagonist of vanilloid TRPV1 receptor. The number of gastric lesions was determined by planimetry, the gastric blood flow (GBF) was assessed by H2-gas clearance technique, the plasma gastrin concentrations were measured using the radioimmunoassay (RIA) and the expression of mRNA for tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in gastric mucosa was evaluated by reverse transcription polymerase chain reaction (RT-PCR). Curcumin dose-dependently reduced the WRS-induced gastric lesions, the dose inhibiting these lesions by 50% being about 50 mg/kg. These effects of curcumin were accompanied by an increase in GBF and the reduction in basal and histamine- or pentagastrin-stimulated gastric acid secretion. The protective and hyperemic activities of curcumin (50 mg/kg i.g.) against WRS lesions were significantly attenuated (P < 0.05) in rats pretreated with rofecoxib and SC-560 and completely reversed (P < 0.01) by indomethacin. L-NNA significantly reduced (P < 0.05) the decrease in WRS-induced lesions and the accompanying rise in GBF caused by curcumin and these effects were restored by concurrent treatment with L-arginine (200 mg/kg i.g.). The curcumin-induced decrease in the number of WRS-induced gastric lesions and accompanying increase in the GBF were significantly attenuated (P < 0.05) in capsaicin-denervated rats and in those pretreated with capsazepine. These effects of curcumin in rats with capsaicin denervation were restored by concomitant treatment with exogenous calcitonin gene related pepetide (CGRP) combined with curcumin and subsequently exposed to WRS. The expression of mRNA for TNF-α, COX-2 and iNOS was significantly increased (P < 0.05) in vehicle-pretreated control rats exposed to WRS and significantly attenuated (P < 0.05) by curcumin administered in graded dosages. We conclude that curcumin exerts gastroprotective and hyperemic activities against experimental stress-induced gastric lesions by mechanism involving endogenous prostaglandins, NO, the neuropeptides such as CGRP released from capsaicin-sensitive afferent nerves and the activation of vanilloid TRPV1 receptors located on these sensory nerve terminals.

In numerous vascular beds, acetylcholine (ACh) evokes the simultaneous release of endothelium-derived relaxing and contracting factors (EDRF and EDCF, respectively). We aimed to determine whether ACh evokes the release of an EDCF in the chicken ductus arteriosus (DA) and to identify its nature. Isolated rings DA from 19-d chicken embryos (total incubation: 21-d) were studied in a wire myograph. Low concentrations of ACh (30 nM-1 microM) elicited a relaxation, which was followed by a contraction at higher concentrations (3 microM-0.1 mM). Both relaxation and contraction were abolished by removal of endothelium and were sensitive to the antimuscarinic agents atropine and 4-DAMP (M3-receptor antagonist). ACh-induced contraction was impaired in the presence of the non-selective inhibitor of cyclooxygenase (COX) indomethacin, the selective COX-1 inhibitor valeryl salicylate, and the thromboxane (TX)/prostaglandin (PG) H2 (TP) receptor blocker SQ-29458, whereas the response was not affected by the selective COX-2 inhibitor nimesulide, the TX synthase inhibitor furegrelate, the H2O2 scavenger PEG-catalase, the nitric oxide synthase inhibitor L-NAME, or the soluble guanylate cyclase inhibitor ODQ. Enzyme immunoassay determined that, under basal conditions, the chicken DA produced PGE2, PGF2alpha and TXB2 (stable metabolite of TXA2). Prostanoid production was inhibited by indomethacin but was not significantly affected by ACh. We conclude that in the chicken DA, stimulation of muscarinic receptors by ACh induces an endothelium-dependent relaxation followed by an endothelium-dependent contraction. The contraction involves COX-1 activation and TP receptor stimulation.

BACKGROUND

There is a lack of evidence for the efficacy of preventive medications for peptic ulcers (PUs) among long-term users of non-steroidal anti-inflammatory drugs (NSAIDs) in Japan.

OBJECTIVE

To estimate the preventive effect by normal dose, not high-dose histamine-H2 receptor antagonists (H2RA) for NSAID-induced ulcers.

METHODS

We designed two different studies to assess the efficacy of anti-ulcer agents in rheumatoid arthritis (RA) in patients treated over a long term with NSAIDs. An investigative survey divided patients into those not taking anti-ulcer agents (non-medication group); those taking mucosal protective agents (mucosal protectant group), H2RA (H2RA group), proton pump inhibitors (PPI group), or a prostaglandin E1 analog (PG) (PG group). The second study compared prospectively the preventive effects of either famotidine 20 mg bd (famotidine group) or lansoprazole 15 mg daily (lansoprazole group) in patients with PU scars.

RESULTS

The prevalence of PU in the H2RA group was significantly lower compared to the mucosal protectant group (P < 0.05), and the mucosal protectant group was not significantly different to the non-medication group. The prospective study revealed that the PU onset rate of the famotidine group was 8% (1/13), and lansoprazole group was 15% (2/13), indicating no significant differences between the two.

CONCLUSIONS

In Japan, normal-dose H2RA is expected to be a new PU preventive treatment strategy in patients requiring long-term NSAID therapy.

Cyclooxygenase (COX) converts arachidonic acid to prostaglandin (PG) H2, which is further metabolized to various prostaglandins, prostacyclin and thromboxane A2. COX exists in at least two different isoforms. COX-1 is constitutively expressed, whereas COX-2 is induced by proinflammatory stimuli. Prostaglandin E2 is a major metabolite of COX activation. In order to compare the activity of target ligands and COX inhibitors on PGE2 synthesis and release, the responsiveness of several cell lines to the calcium ionophore A23187, bacterial lipopolysaccharide (LPS), nonsteroidal anti-inflammatory drugs (NSAIDs), and the glucocorticoid, dexamethasone, were investigated. For intracellular measurements, the culture supernatant was aspirated, and the cells were thoroughly washed and lysed with dodecyltrimethylammonium bromide. Intracellular and secreted PGE2 were measured with an enzyme immunoassay. A23187 and LPS increased intracellular PGE2 in a dose-dependent manner. Kinetic experiments with A23187-stimulated mouse 3T3 fibroblast cells revealed a distinct biphasic response in COX activity. In the presence of NSAIDs or dexamethasone, there was a dose-dependent inhibition in intracellular PGE2 with A23187-stimulated 3T3 cells. Inhibitory studies demonstrated an apparent increased sensitivity of COX activity to the action of inhibitors when measuring intracellular PGE2 compared with using cell culture supernatants. Indeed, intracellular PGE2 levels were comprehensively reduced in the presence of low concentrations of inhibitor. The utilization of cell culture lysates and, in particular, measurement of intracellular PGE2 should prove useful for identifying new COX inhibitors.

OBJECTIVE

A decrease in gastrin and pepsinogen (PG) levels 1 month after Helicobacter pylori eradication has been described repeatedly, but the long-term progression of such a decrease has been scarcely studied. We therefore studied the effect of H. pylori eradication on basal and stimulated gastrin and PG levels for 1 year. Initially, the usefulness of measuring these parameters for the noninvasive diagnosis of H. pylori eradication was validated. Furthermore, an assessment was made of the association between H. pylori reinfection and a re-increase in gastrin and PG values. Finally, an evaluation was made of the variables influencing gastrin and PG concentration, with particular attention to H. pylori infection and histological lesions of gastric mucosa.

METHODS

Two-hundred and twenty-two patients with duodenal ulcer were studied prospectively. Exclusion criteria were the administration of antibiotics, H2 antagonists, omeprazole or bismuth prior to endoscopy. In all patients serum basal levels of gastrin, PGI, and PGII were measured before and 1 month after completing eradication therapy. In the successfully eradicated patients, gastrin, PGI, and PGII were also measured at 6 and 12 months. In 80 patients stimulated measurements of gastrin (after ingestion of two beef cubes) and PGI (after injection of pentagastrin) were also performed. H. pylori-negative patients after therapy underwent a urea breath test at 6 and 12 months, and patients who had stimulated gastrin and PG concentration measured had also an endoscopy performed at 6 months.

RESULTS

H. pylori was eradicated in 73% of patients. A histological improvement was observed 1 month after completing H. pylori eradication therapy, both at gastric antrum and body (P < 0.001), while a further improvement at antrum was demonstrated at 6 months (P < 0.01). With regard to the different cut-off points for decreased basal and stimulated measurements for diagnosing H. pylori eradication, the best results were obtained, respectively, with PGII (sensitivity of 90% and specificity of 76%) and PGI 30 min after stimulation (sensitivity and specificity of 82%), with an area under the ROC curve of 0.87 in both cases. In the multiple regressions analysis H. pylori status correlated with gastrin, PGI and PGII after therapy (P < 0.001), while histological lesions correlated only with gastrin levels (P < 0.05). A decrease in basal and stimulated serum parameters was demonstrated immediately after eradication (Wilcoxon test, P < 0.001), and an additional decrease (at 6 months) was observed just in PGI (Friedman test, P < 0.01). However, gastrin and PGII values remained unchanged after the first month post-eradication. Seven patients were reinfected with H. pylori during follow-up. Quantitation of basal and stimulated gastrin and PGI levels was not reliable as a reinfection marker. Regarding basal PGII, the parallelism was strong at 6 months (re-increase in all four reinfected patients), although only in one out of three with reinfection at 1 year did PGII rise at that stage.

CONCLUSIONS

(1) Measurement of gastrin and PG levels (especially basal PGII values) is a useful non-invasive method to confirm H. pylori eradication after therapy. (2) H. pylori eradication is associated with a significant decrease in basal and stimulated gastrin levels and in basal PGII levels that is detected immediately (1 month) after finishing treatment, and remains unchanged for 1 year. However, the decrease in basal and stimulated PGI levels occurs progressively for 6 months, although such levels remain also unchanged afterwards. (3) Measurement of gastrin and PGI concentrations has a limited usefulness in the diagnosis of H. pylori reinfections after successful eradication, although PGII determination could be more useful in this situation.

We have shown that lymphocytes from atopics are more sensitive to histamine-induced suppression of mitogen transformation than are cells from normal subjects. Recent reports have suggested that histamine suppression may act via prostaglandin synthesis. We have investigated this and found that indomethacin partially reversed the histamine suppression seen in atopics, but not that in normals. This effect was seen even when the direct enhancing effect of indomethacin was taken into account. The direct effect of indomethacin on mitogen-induced transformation was similar in both normal and atopic cultures, which suggests that these results are not due to the presence of PG producing cells in atopic cultures, but rather that histamine modulates the function of these cells. It was found that a specific H2 agonist, but not an H1 agonist could partially mimic the effect of histamine this system.

Cyclooxygenase-2 selective inhibitors (COXIBs) were developed with the prime object of minimizing gastrointestinal adverse effects, which are seen with the use of traditional nonsteroidal anti-inflammatory drugs (NSAIDs). Their long-term use is limited by the development of hypertension, edema, and congestive heart failure in a significant proportion of patients. NSAIDs block the activity of both COX isozymes, COX-1 and COX-2, which mediate the enzymatic conversion of arachidonate to prostaglandin H2 (PGH2) and other prostaglandin (PG) metabolites. It is well established that the cardiovascular profile of COX-2 inhibitors can be accounted for by inhibition of COX-dependent PG synthesis. Following the COX-mediated synthesis of PGH2 from arachidonate, PGH2 is metabolized to one of at least five bioactive PGs, including PGE2, PGI2, PGF2, PGD2, or thromboxane A2 (TXA2). These prostanoids have pleiotropic cardiovascular effects, altering platelet function and renal function, and they are acting either as vasodilators or vasoconstrictors. Although COX-1 and COX-2 exhibit similar biochemical activity in converting arachidonate to PGH2 in vitro, the ultimate prostanoids they produce in vivo may be different due to differential regulation of COX-1 and COX-2, tissue distribution, and availability of the prostanoid synthases. PGs have been established as being critically involved in mitigating hypertension, helping to maintain medullary blood flow (MBF), promoting urinary salt excretion, and preserving the normal homeostasis of thrombosis, and the researchers found that the use of COX-2 inhibitors caused many serious complications in altering the normal body homeostasis. The purpose of the present research is to explain briefly the side effects of COX-2 inhibitors on the renal and cardiovascular system.

A new double photosystems-based 'Z-scheme' photoelectrochemical (PEC) sensing platform is designed for ultrasensitive detection of prostate-specific antigen (PSA) by coupling with a three-dimensional (3D) DNA walker. Two photosystems consist of CdS quantum dots (photosystem I; PS I) and BiVO4 photoactive materials (photosystem II; PS II), whereas gold nanoparticles (AuNPs) photodeposited on high-active {010} facets of BiVO4 are used as the electron mediators to promote electron transfer from conduction band of PS II to valence band of PS I. 3D DNA walker-based amplification strategy is carried out between hairpin DNA1 conjugated onto the AuNP, hairpin DNA2 labeled with CdS quantum dot (QD-H2), and DNA walker complementary with the PSA aptamer modified to a magnetic bead (Apt-MB). Upon addition of target, DNA walker strand is displaced from DNA walker/Apt-MB to open hairpin DNA1 on AuNP@BiVO4. In the presence of QD-H2, DNA walker induces the hybridization of DNA1 with DNA2 on the gold nanoparticles step by step, thereby resulting in the assembly of CdS QDs on the AuNP@BiVO4 to form Z-scheme double photosystems with strong photocurrent. Under optimum conditions, the Z-scheme PEC sensing system exhibits good photocurrent responses toward target PSA within the working range of 0.01-50 ng mL-1 at a low detection limit of 1.5 pg mL-1. Good reproducibility and accuracy are acquired for analysis of target PSA and human serum specimens relative to the commercial PSA ELISA kit. Importantly, our strategy provides a new horizon for photoelectrochemical in vitro diagnostics.

Strain H5(T) was isolated from a sediment sample collected from the coastal area of Qingdao, China. The cells were Gram-stain-positive, non-motile, straight or curved rods. The temperature range for growth was 20-37 °C and the pH for growth ranged from 6.5 to 9.0, with optimum growth occurring in the temperature range 28-30 °C and pH range 7.5-8.0. Growth occurred in the presence of 0-6% (w/v) NaCl (optimum, 0-2%). Strain H5(T) had MK-9, MK-9(H2) and MK-9(H4) as the major menaquinones and C18:1ω9c, C16:0, C14:0, C18:0 and C16:1ω9c as major fatty acids. The cell-wall peptidoglycan type was A5α l-Lys-l-Ala-l-Lys-d-Glu. The major polar lipids were phosphatidylglycerol (PG), an unknown phospholipid (PL1) and two unknown phosphoglycolipids (PGL1, PGL2). An unknown phospholipid (PL2) and two unknown glycolipids (GL1, GL2) were present in moderate to minor amounts in the polar lipid profile. The genomic DNA G+C content was 61.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain H5(T) represents a novel lineage in the family Actinomycetaceae. On the basis of phenotypic, physiological and molecular characteristics, it is proposed that the novel isolate should be classified as a novel species in a new genus: Flaviflexus huanghaiensis gen. nov., sp. nov., with strain H5(T) ( = DSM 24315(T) =CICC 10486(T)) as the type strain of the type species.

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The prevalence of vitamin B12 deficiency varies from 5.8% to 30% among patients undergoing long-term treatment with metformin. Because of the paucity of data on Brazilian patients, this study aimed to determine the frequency of B12 deficiency and related factors among Brazilian patients with type 2 diabetes mellitus (T2DM) using metformin.

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Cross-sectional study at a public university hospital.

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Patients with T2DM and a control group of non-diabetics were included. Serum B12 levels were measured and biochemical B12 deficiency was defined as serum levels < 180 pg/ml. Associations between B12 deficiency and age, duration of T2DM, duration of use and dosage of metformin, and use of proton pump inhibitors (PPIs) or histamine H2 antagonists were determined.

UNASSIGNED

231 T2DM patients using metformin (T2DM-met) and 231 controls were included. No difference in the frequency of PPI or H2-antagonist use was seen between the groups. B12 deficiency was more frequent in the T2DM-met group (22.5% versus 7.4%) and this difference persisted after excluding PPI/H2-antagonist users (17.9% versus 5.6%). The factors that interfered with serum B12 levels were PPI/H2-antagonist use and duration of metformin use ≥ 10 years. Use of PPI/H2-antagonists was associated with B12 deficiency, with an odds ratio of 2.60 (95% confidence interval, 1.34-5.04).

UNASSIGNED

Among T2DM patients, treatment with metformin and concomitant use of PPI/H2-antagonists are associated with a higher chance of developing B12 deficiency than among non-diabetics.

Anti-ulcer prostaglandins (PG)--misoprostol, enprostil and rioprostil--have been given to more than 5000 patients in short-term studies on gastric and duodenal ulcer. Analysis of these studies shows the drugs to be safe. Their side effects appear to be dose-dependent and mainly restricted to the gastrointestinal system, the major syndromes being diarrhoea and abdominal pain. The clinical relevance of PG-related unwanted effects, though in average exceeding that of H2-blockers, seems to be sufficiently low. In terms of safety efficacy, however, they appear inferior to H2-antagonists, so their routine use in preference to the latter compounds is still premature.

Omeprazole efficacy and tolerance were evaluated in 20 patients with longstanding Zollinger-Ellison syndrome (ZES) committed to long-term antisecretory therapy. The study included 13 men and 7 women, aged 53 (30-74) years (median and range). Nineteen patients presented with epigastric pain, 14 with vomiting, and 9 with diarrhea. All patients had gastroduodenal ulcerations, associated with esophagitis in 9 cases. Median and extreme values for basal acid output (BAO) and serum gastrin (SG) levels before omeprazole treatment were 41 (3.7-80) mmol H+/h and 413 (111-11,490) pg/ml, respectively. In 18 patients, omeprazole treatment was initiated because of resistance to H2-antagonists, and in 2 patients because of carbothioamide RP 40749 discontinuation. Initial doses of omeprazole were 60 mg per day in 10 patients and ranged from 80 to 160 mg per day in the others. Esophagogastrectomy was performed in one patient at day 15 because of esophageal stenosis. In the remaining 19 patients, median duration of treatment was 16 (7-54) months and median doses of omeprazole were 70 (20-160) mg per day during the survey. Omeprazole therapy was highly effective in inducing rapid disappearance of clinical abnormalities in 18 of 19 patients. Twenty-two days after initiation of treatment, median BAO was 4 (0-14) mmol/h and ulcerations had healed in 17 of 19 patients. Median BAO was less than 5 mmol/h during follow-up. However, asymptomatic ulcer recurrence was noted in 4 patients, but disappeared quickly after omeprazole doses were increased. Median basal gastrin level was 700 (116-36.625) pg/ml at the least determination and was statistically higher than pretreatment values (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Hydrogen sulphide (H2S) is an endogenous inflammatory mediator produced by cystathionine-γ-lyase (CSE) in monocytes/macrophages. To determine the role of H2S and macrophages in inflammation, we used small interference RNA (siRNA) to target the CSE gene and investigated its effect in a mouse model of acute pancreatitis. Acute pancreatitis is characterised by increased levels of plasma amylase, myeloperoxidase (MPO) activity and pro-inflammatory cytokines and chemokines in the pancreas and lung. SiRNA treatment attenuated inflammation in the pancreas and lungs of mice following caerulein-induced acute pancreatitis. MPO activity increased in caerulein-induced acute pancreatitis (16.21 ± 3.571 SD fold increase over control) and treatment with siRNA significantly reduced this (mean 3.555 ± 2.522 SD fold increase over control) (p < 0.0001). Similarly, lung MPO activity increased following treatment with caerulein (3.56 ± 0.941 SD fold increase over control) while siRNA treatment significantly reduced MPO activity (0.8243 ± 0.4353 SD fold increase over control) (p < 0.0001). Caerulein treatment increased plasma amylase activity (7094 ± 207 U/l) and this significantly decreased following siRNA administration (5895 ± 115 U/l) (p < 0.0001). Cytokine and chemokine levels in caerulein-induced acute pancreatitis reduced following treatment with siRNA. For example, siRNA treatment significantly decreased pancreatic and lung monocyte chemoattractant protein (MCP)-1 (169.8 ± 59.75 SD; 90.01 ± 46.97 SD pg/ml, respectively) compared to caerulein-treated mice (324.7 ± 103.9 SD; 222.8 ± 85.37 SD pg/ml, pancreas and lun,g respectively) (p < 0.0001). These findings show a crucial pro-inflammatory role for H2S synthesised by CSE in macrophages in acute pancreatitis and suggest CSE gene silencing with siRNA as a potential therapeutic approach for this condition.

The effects of 2-deoxy-D-glucose (2-DG) on plasma levels of somatostatin-like immunoreactivity (SLI) were examined in conscious normal dogs. After an iv infusion of 2-DG (400 mg/kg . h for 15 min), plasma SLI rose significantly from a mean baseline of 130 +/- 5 pg/ml (mean +/- SEM) to a mean peak of 204 +/- 25 pg/ml (P less than 0.005) at 25 min. Plasma insulin and glucagon also increased significantly. Atropine (200 microgram/kg . h for 35 min, iv) and hexamethonium (5 mg/kg, iv) markedly suppressed the SLI response to 2-DG, suggesting that it might be mediated, at least in part, by the autonomic nervous system. In contrast, the plasma insulin and plasma glucagon responses to this glucose analog were only slightly affected by atropine or hexamethonium pretreatment. Carbachol (0.2 mg, sc) caused a mean maximal increase in SLI of 43 +/- 14% (P less than 0.005) and atropine (200 micrograms/kg . h, iv) caused a mean maximal decrease of 25 +/- 2% (P less than 0.001) from the respective baseline levels. Plasma insulin and glucagon rose promptly after carbachol and were unchanged by atropine. To assess th contribution of 2-DG-stimulated gastric acid secretion in the 2-DG-induced SLI rise 2-DG was infused during the infusion of the H2-receptor antagonist cimetidine (3.0 mg/kg . h). Plasma SLI, nevertheless, increased significantly from a mean baseline of 112 +/- 6 pg/ml to a mean peak of 158 +/- 19 pg/ml (P less than 0.005) at 20 min, although the magnitude of the response was substantially reduced (P = NS). These observations suggest that in the conscious dog, 2-DG stimulates SLI secretion in part via cholinergic mechanism.