Validated image ordering guidelines for odontogenic infections.

Overuse of computed tomography (CT) is a prevalent problem across multiple disciplines in healthcare and is common in the workup of odontogenic infections. To address this problem, an imaging pathway was created through collaboration of the oral maxillofacial surgery and emergency medicine departments to reduce unnecessary CT orders. A prospective study was implemented to assess the success of the imaging pathway to guide in the selection of the most appropriate radiological imaging modality when managing an odontogenic infection. Subjects included were adults, presenting through the emergency department for confirmed odontogenic infection. The primary outcome was the rate of unnecessary CT scans performed after the introduction of the pathway. Statistics were performed via the t-test, χ2 test, and multiple regression analysis; P < 0.05 was considered significant. Between February 1 and December 15, 2019, 100 patients met the inclusion criteria and were enrolled. The rate of unnecessary CT scans was 25.6%, compared to 56.6% prior to the introduction of the imaging pathway. The pathway did not misclassify any patient to not receive a CT when it was medically necessary. Use of the imaging pathway has the potential to reduce unnecessary CT imaging for odontogenic infections, without negatively affecting patient outcomes.

The effects of cannabidiol on the antigen-induced contraction of airways smooth muscle in the guinea-pig.

(-)-Δ(9)-Tetrahydrocannabinol has been demonstrated to have beneficial effects in the airways, but its psychoactive effects preclude its therapeutic use for the treatment of airways diseases. In the present study we have investigated the effects of (-)-cannabidiol, a non-psychoactive component of cannabis for its actions on bronchial smooth muscle in vitro and in vivo. Guinea-pig bronchial smooth muscle contractions induced by exogenously applied spasmogens were measured isometrically. In addition, contractile responses of bronchial smooth muscle from ovalbumin-sensitized guinea-pigs were investigated in the absence or presence of (-)-cannabidiol. Furthermore, the effect of (-)-cannabidiol against ovalbumin-induced airway obstruction was investigated in vivo in ovalbumin-sensitized guinea-pigs. (-)-Cannabidiol did not influence the bronchial smooth muscle contraction induced by carbachol, histamine or neurokinin A. In contrast, (-)-cannabidiol inhibited anandamide- and virodhamine-induced responses of isolated bronchi. A fatty acid amide hydrolase inhibitor, phenylmethanesulfonyl fluoride reversed the inhibitory effect of (-)-cannabidiol on anandamide-induced contractions. In addition, (-)-cannabidiol inhibited the contractile response of bronchi obtained from allergic guinea-pigs induced by ovalbumin. In vivo, (-)-cannabidiol reduced ovalbumin-induced airway obstruction. In conclusion, our results suggest that cannabidiol can influence antigen-induced airway smooth muscle tone suggesting that this molecule may have beneficial effects in the treatment of obstructive airway disorders.

Evidence for both inverse agonism at the cannabinoid CB1 receptor and the lack of an endogenous cannabinoid tone in the rat and guinea-pig isolated ileum myenteric plexus-longitudinal muscle preparation.

BACKGROUND AND PURPOSE: Cannabinoid receptor agonists reduce intestinal propulsion in rodents through the CB(1) receptor. In addition to its antagonistic activity at this receptor, rimonabant (N-(piperidino)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxyamide) alone augments intestinal transit. Using rat and guinea-pig ileum MPLM (myenteric plexus-longitudinal muscle) preparations, we investigated whether the latter effect was through inverse agonism or antagonism of endocannabinoid agonist(s). EXPERIMENTAL APPROACH: Inverse agonism was investigated by comparing the maximal enhancement of electrically evoked contractions of the MPLM by two CB(1) receptor antagonists, AM 251 (N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide) and O-2050 [(6aR,10aR)-3-(1-methanesulphonylamino-4-hexyn-6-yl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6-H-dibenzo[b,d]pyran], with that produced by rimonabant. To reveal ongoing endocannabinoid activity, effects of inhibiting endocannabinoid hydrolysis by fatty acid amide hydrolase (FAAH) using AA-5HT (arachidonyl-5-hydroxytryptamine), PMSF (phenylmethylsulphonyl fluoride) or URB-597 (3'-carbamoyl-biphenyl-3-yl-cyclohexylcarbamate), or putative uptake using VDM-11 [(5Z,8Z,11Z,14Z)-N-(4-hydroxy-2-methylphenyl)-5,8,11,14-eicosatetraenamide] was evaluated. KEY RESULTS: The presence of CB(1) receptors was revealed by antagonism of exogenous anandamide, arachidonylethanolamide (AEA) and WIN 55,212-2 [(R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)-pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone mesylate] by rimonabant. The rank order of potentiation of contractions was AM 251 > rimonabant > O-2050. Neither the FAAH inhibitors nor VDM-11 affected electrically evoked contractions. Each FAAH inhibitor increased the potency of AEA but not WIN 55,212-2. VDM-11 did not alter the inhibitory effect of AEA. CONCLUSIONS AND IMPLICATIONS: The different levels of maximal potentiation of contractions by the CB(1) receptor antagonists suggest inverse agonism. The potentiation of the action of AEA by the FAAH inhibitors showed that FAAH was present. The lack of effect of FAAH inhibitors and VDM-11 alone on electrically evoked contractions, and on the potency of exogenous AEA suggests that pharmacologically active endocannabinoids were not released and the endocannabinoid transporter was absent. Thus, the CB(1) receptor antagonists behave as inverse agonists.

The effects of Delta-tetrahydrocannabinol and cannabidiol alone and in combination on damage, inflammation and in vitro motility disturbances in rat colitis.

BACKGROUND AND PURPOSE: Cannabis is taken as self-medication by patients with inflammatory bowel disease for symptomatic relief. Cannabinoid receptor agonists decrease inflammation in animal models of colitis, but their effects on the disturbed motility is not known. (-)-Cannabidiol (CBD) has been shown to interact with Delta(9)-tetrahydrocannabinol (THC) in behavioural studies, but it remains to be established if these cannabinoids interact in vivo in inflammatory disorders. Therefore the effects of CBD and THC alone and in combination were investigated in a model of colitis. EXPERIMENTAL APPROACH: The 2,4,6-trinitrobenzene sulphonic acid (TNBS) model of acute colitis in rats was used to assess damage, inflammation (myeloperoxidase activity) and in vitro colonic motility. Sulphasalazine was used as an active control drug. KEY RESULTS: Sulphasalazine, THC and CBD proved beneficial in this model of colitis with the dose-response relationship for the phytocannabinoids showing a bell-shaped pattern on the majority of parameters (optimal THC and CBD dose, 10 mg.kg(-1)). THC was the most effective drug. The effects of these phytocannabinoids were additive, and CBD increased some effects of an ineffective THC dose to the level of an effective one. THC alone and in combination with CBD protected cholinergic nerves whereas sulphasalazine did not. CONCLUSIONS AND IMPLICATIONS: In this model of colitis, THC and CBD not only reduced inflammation but also lowered the occurrence of functional disturbances. Moreover the combination of CBD and THC could be beneficial therapeutically, via additive or potentiating effects.

Pharmacological characterization of cannabinoid receptor activity in the rat-isolated ileum myenteric plexus-longitudinal muscle preparation.

BACKGROUND AND PURPOSE: Cannabinoid effects on intestinal transit are commonly evaluated in rats. We characterized the cannabinoid receptors mediating the inhibitory effect of 5-(1,1-dimethylheptyl)-2-[5-hydroxy-2-(3-hydroxypropyl)-cyclohexyl]-phenol (CP 55,940), (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone mesylate (WIN 55,212-2), arachidonylethanolamide (AEA) and Delta(9)-tetrahydrocannabinol (Delta(9)-THC) on contractions of the rat ileum myenteric plexus-longitudinal muscle (MPLM) preparation. EXPERIMENTAL APPROACH: The interaction of each agonist was examined with the CB(1) and CB(2) receptor antagonist rimonabant and SR 144,528 respectively, on contractions elicited by electrical field stimulation (EFS) or exogenous ACh. The interaction of AEA with capsazepine, a TRPV(1) receptor antagonist, was also investigated. KEY RESULTS: EFS with single and trains of pulses evoked neurogenic ACh-mediated twitch and rebound contractions respectively. The rank order of potency for inhibition was CP 55,940 = WIN 55,212-2 > AEA > Delta(9)-THC and AEA > WIN 55,212-2 =Delta(9)-THC = CP 55,940 respectively. The stereoisomer WIN 55,212-3 was without effect. Rimonabant antagonized the inhibition of the twitches with pK(B) values of around 8.60, but only antagonized rebound contractions induced by WIN 55,212-2, AEA and Delta(9)-THC, with pA(2) values of around 6.80. Rimonabant increased the twitches but inhibited the rebound contractions. Contractions to exogenous ACh were not altered. These observations extended to the guinea pig ileum MPLM. CONCLUSIONS AND IMPLICATIONS: The rat MPLM contains CB(1) receptors and at least two non-CB(1)-non-CB(2)-non-TRPV(1) receptors attenuating EFS-evoked ACh-mediated contractions in an EFS frequency-dependent pre-synaptic and stereo-specific manner. Augmentation of the twitches by rimonabant may be through antagonism of an endocannabinoid tone or inverse agonism, whereas inhibition of the rebound contractions involved partial agonism.

Characterisation of nicotine receptors on human peripheral blood mononuclear cells (PBMC).

AIM AND OBJECTIVE: The aim of the work was to characterise the nAChRs on human PBMC. METHOD: PBMC were isolated from human blood buffy coats provided by the blood transfusion service and were used for radioligand binding studies with [(3)H]-nicotine. RT-PCR experiments were used to determine nAChR subunit expression while immunoblotting experiments were used to confirm that nAChR subunits identified by RT-PCR were translated into protein. RESULTS: Binding studies suggested the presence of one binding site for (-)- nicotine on human peripheral blood lymphocytes. Competition studies showed that only (-)- nicotine, epibatidine and alpha-bungarotoxin, displaced radiolabelled nicotine from cells. RT-PCR studies demonstrated mRNA for alpha4, alpha5, alpha7, beta1 and beta2 nAChRs subunits in PBMC. Expression of mRNA for the a5 subunit of nAChR was observed in all lymphocyte samples tested. In contrast, the expression pattern of mRNAs for alpha4, alpha7, beta1, and beta2 mRNAs subunits of nAChRs, varied between samples. Western blot analysis showed that protein for alpha4, alpha5, and alpha7 and beta2 nAChR subunits was expressed in most, but not all of the PBMC samples tested but some of the bands obtained were faint. CONCLUSION: The results obtained suggest that human PBMC contain nAChRs containing alpha4beta2, alpha4beta2alpha5, and/or alpha7 subunits.

Neural correlates of lexical access during visual word recognition.

People can discriminate real words from nonwords even when the latter are orthographically and phonologically word-like, presumably because words activate specific lexical and/or semantic information. We investigated the neural correlates of this identification process using event-related functional magnetic resonance imaging (fMRI). Participants performed a visual lexical decision task under conditions that encouraged specific word identification: Nonwords were matched to words on orthographic and phonologic characteristics, and accuracy was emphasized over speed. To identify neural responses associated with activation of nonsemantic lexical information, processing of words and nonwords with many lexical neighbors was contrasted with processing of items with no neighbors. The fMRI data showed robust differences in activation by words and word-like nonwords, with stronger word activation occurring in a distributed, left hemisphere network previously associated with semantic processing, and stronger nonword activation occurring in a posterior inferior frontal area previously associated with grapheme-to-phoneme mapping. Contrary to lexicon-based models of word recognition, there were no brain areas in which activation increased with neighborhood size. For words, activation in the left prefrontal, angular gyrus, and ventrolateral temporal areas was stronger for items without neighbors, probably because accurate responses to these items were more dependent on activation of semantic information. The results show neural correlates of access to specific word information. The absence of facilitatory lexical neighborhood effects on activation in these brain regions argues for an interpretation in terms of semantic access. Because subjects performed the same task throughout, the results are unlikely to be due to task-specific attentional, strategic, or expectancy effects.

Modulation of the release of endogenous adenosine by cannabinoids in the myenteric plexus-longitudinal muscle preparation of the guinea-pig ileum.

1. Interactions between the cannabinoid system and the adenosine system were investigated in the myenteric plexus-longitudinal muscle (MPLM) of the guinea-pig ileum. 2. Electrically-evoked contractions of the MPLM were inhibited in a concentration dependent manner by exogenous adenosine and the adenosine receptor agonist 2-chloroadenosine. These inhibitory effects were reversed by the selective A(1) receptor antagonist DPCPX (20 nM). 3. Preincubation of the MPLM with the cannabinoid receptor agonist CP55,940 (1 nM) or the endogenous cannabinoid ligand anandamide caused a significant leftward shift in the concentration-effect curves to adenosine and 2-chloroadenosine. 4. Electrically-evoked contractions of the MPLM were inhibited in a concentration dependent manner by the adenosine uptake inhibitor dipyridamole. This inhibition was reversed by DPCPX (20 nM). 5. Pretreatment with CP55,940 (1 nM) or anandamide (10 microM) significantly reduced the inhibition produced by dipyridamole, an effect which was completely reversed by the selective CB(1) receptor ligand SR141716 (100 nM). 6. Electrically evoked adenosine release, measured in real time by means of adenosine-specific biosensors, was inhibited by CP55,940 (10 nM). This inhibition was blocked when CP55,940 was applied in the presence of SR141716 (100 nM). 7. These results confirm the presence of presynaptic CB(1) and A(1) receptors in the guinea-pig MPLM, and suggest that CB(1) receptor stimulation reduces electrically-evoked adenosine release. Overall the data raise the possibility that the cannabinoid system plays a role in the modulation of adenosine transmission in the MPLM.

GABA(B) receptor function in the ileum and urinary bladder of wildtype and GABA(B1) subunit null mice.

1. GABA(B1) receptor subunit knockout mice were generated and the effects of the GABA(B) receptor agonist, baclofen, were evaluated within the peripheral nervous system (PNS) of wildtype (+/+), heterozygote (+/-) and knockout (-/-) animals. For this purpose, neuronally-mediated responses were evoked in both the isolated ileum and urinary bladder, using selective electrical field stimulation (EFS). 2. In ileum resected from 4-8-week-old-mice, low frequencies of EFS (0.5 Hz) evoked irregular muscle contractions which were prevented by atropine 1 microM and reduced by baclofen (33.4 +/- 5.6%, 100 microm). The latter effect was antagonized by the GABA(B) receptor antagonist CGP54626 0.2 microm. Baclofen 100 microm did not affect contractions of similar amplitude induced by carbachol, indicating that the ability of baclofen to inhibit cholinergic function in mouse ileum may be due to an action at prejunctional GABA(B) receptors. 3. To avoid the development of grand mal seizure by GABA(B1) (-/-) mice, a behaviour observed when the mice were greater than 3 weeks old, it was necessary to study the effects of this knockout in 1-3-week-old-animals. However, at this age, EFS at 0.5 Hz did not evoke robust muscle contractions. Consequently we used EFS at 5 Hz, which did evoke cholinergically mediated contractions, found to be of similar amplitude in (+/+) and (+/-) mice, of both 1-3 weeks and 4-8 weeks of age. At this frequency of EFS, baclofen reduced the amplitude of the evoked contractions [n = 6 (+/+) and n = 5 (+/-), IC50 19.2 +/- 4.8 microm) and this effect was greatly reduced in the presence of CGP54626 0.2 microm. 4. In urinary bladder from 1-3-week-old-mice, using higher frequencies of EFS to evoke clear, nerve-mediated contractions (10 Hz), baclofen 10-300 microm concentration-dependently inhibited contractions in (+/+) mice (IC50 9.6 +/- 3.8 microm). This effect was inhibited by CGP54626 (0.2 microm, 46.2 +/- 13.6% inhibition, 300 microm baclofen n = 7) a concentration which, by itself, had no effect on the EFS-evoked contractions. 5. The effects of baclofen in both ileum and urinary bladder were absent in the GABA(B1) receptor subunit (-/-) mice; however, responses to EFS were unaffected in (-/-) when compared to the (+/+) mice. 6. Our data suggest that, as in the central nervous system (CNS), the GABA(B1) receptor subunit is an essential requirement for GABA(B) receptor function in the enteric and PNS. As such, these data do not provide a structural explanation for the existence of putative subtypes of GABA(B) receptor, suggested by studies such as those in which different rank-orders of GABA(B) agonist affinity have been reported in different tissues.

Activation of presynaptic A1-receptors by endogenous adenosine inhibits acetylcholine release in the guinea-pig ileum.

1. It is well established that presynaptic adenosine A1-receptor activation inhibits acetylcholine (ACh) release in the guinea-pig ileum. The present study extends this observation and examines a possible role for endogenous adenosine in modulating cholinergic nerve function. 2. The actions of the adenosine uptake blocker, dipyridamole, the adenosine deaminase inhibitor, erythro-9(2-hydroxy-3-nonyl)adenine (EHNA) and the A1-receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) were examined on electrically evoked neurogenic, cholinergic twitch contractions of the guinea-pig ileum. Some additional studies measuring [3H]-ACh release were also performed. 3. Adenosine and the selective A1-receptor agonist, 2-chloroadenosine (2-CA), inhibited electrically evoked contractions and, in the case of 2-CA, [3H]-ACh release. The actions were antagonized by DPCPX. At low concentrations, dipyridamole and EHNA enhanced the effect of adenosine causing a leftward shift of the concentration-response curve. In contrast, inhibition induced by 2-CA was unaffected by either dipyridamole or EHNA. 4. When applied alone at higher concentrations, EHNA and dipyridamole produced a concentration-dependent suppression of cholinergic neurotransmission. In both cases, the effect could be reversed by DPCPX. At the same concentration, DPCPX alone produced a small but consistent increase in twitch height and [3H]-ACh release. 5. The data confirm the existence of inhibitory presynaptic adenosine A1-receptors modulating cholinergic nerve function in the guinea-pig ileum and suggests that these receptors can be activated by endogenous adenosine released either as adenosine itself or as an ATP metabolite.

Investigation of nicotine binding to THP-1 cells: evidence for a non-cholinergic binding site.

Nicotine is known to modulate immune function, but reports have produced conflicting evidence as to whether nicotinic acetylcholine (nACh) receptors are responsible for these effects. This study was designed to examine the identity of nicotine-binding sites on immune cells using a human leukaemic monocytic cell line, THP-1, that is known to have functions that are modulated by nicotine. Binding studies were performed on THP-1 whole cells using [3H]nicotine as a probe to analyse any possible nicotine-binding sites on these cells. Saturation analysis of THP-1 cells revealed the presence of 2 distinct binding sites; one with a K(d1) of 3.5 +/- 2.1 x 10(-9) M and a B(max1) of 4100 +/- 560 sites/cell (designated the high-affinity site) and the other with a K(d2) of 27 +/- 9.2 x 10(-9) M and a B(max2) of 11,600 +/- 630 sites/cell (low-affinity site). Competition analysis revealed that one site had an affinity to a range of cholinergic ligands including epibatidine and cytisine. When saturation analysis of [3H](-)-nicotine to THP-1 cells was performed in the presence of 1 x 10(-6) M epibatidine, only one binding site was detected. Comparisons of K(d) and B(max) values showed that the high-affinity site was not occluded by epibatidine. No drugs tested displayed any affinity for the high-affinity site except the two enantiomers of nicotine. The high-affinity site was shown to be stereoselective for the (+)-enantiomer of nicotine as shown by K(i) values produced by competition analysis in the presence of 1 x 10(-6) M epibatidine. These values were 5.7 +/- 0.32 x 10(-11) M and 1.9 +/- 4.9 x 10(-9) M for (+)-nicotine and (-)-nicotine, respectively. This study presents evidence for a possible non-cholinergic binding site that may play a role in the mechanism of immunomodulation by nicotine.

Signal transduction of cannabinoid CB1 receptors in a smooth muscle cell line.

1. The effects of cannabinoid (CB) receptor stimulation on membrane currents in single cells from the Syrian hamster vas deferens cell line DDT1MF-2 were investigated using the whole cell patch clamp technique. 2. The CB receptor agonist CP55,940 evoked a concentration-dependent transient outward current. The selective CB1 receptor ligand SR141716 (1 microM), but not the selective CB2 receptor ligand SR144528 (1 microM), inhibited the outward current. Pertussis toxin (100 ng ml-1 for 20 h) completely abolished the outward current. 3. Western blotting with an antibody against the rat (r)CB1 receptor showed a band characteristic for the CB1 receptor around 63 kDa in DDT1MF-2 cells. 4. The reversal potential for the outward current measured using a voltage ramp protocol was -84 +/- 5 mV. The current was inhibited by the Ca2+-dependent K+ channel blockers iberiotoxin (10 nM) and charybdotoxin (10 nM). 5. Removal of Ca2+ from the bathing solution, or the addition of 0.1 mM Cd2+ completely abolished the outward current evoked by 10 microM CP55,940. 6. The sarcoplasmic Ca2+ pump inhibitor thapsigargin reduced the outward current evoked by 10 microM CP55,940 in a concentration-dependent manner. 7. The mitogen-activating protein kinase (MAP kinase) inhibitor PD98059, but not the phospholipase C inhibitor U73122, inhibited the outward current evoked by 10 microM CP55,940. 8. The adenylyl cyclase inhibitor SQ22,536 (100 microM) and 8-Br-cyclic AMP (10 microM) significantly reduced the outward current evoked by 10 microM CP55,940. 9. Our data suggest that CB1 receptor stimulation in DDT1MF-2 cells leads to activation of a large conductance Ca2+-dependent K+ channel through a Gi/Go protein-mediated rise in [Ca2+]i, for which both inhibition of adenylyl cyclase and activation of MAP kinase are required. In addition, the cannabinoid-induced increase in [Ca2+]i is likely to arise from capacitive Ca2+ entry.

Signaling mechanisms coupled to presynaptic A(1)- and H(3)-receptors in the inhibition of cholinergic contractile responses of the guinea pig ileum.

The mechanisms coupled to adenosine A(1)- and histamine H(3)-receptors have been examined in the presynaptic inhibition of acetylcholine (ACh) release from the guinea pig ileum. Electrically evoked twitch contractions were used as a measure of neuronal ACh release. A(1)- and H(3)-receptors were activated by adenosine and R-(alpha)-methylhistamine (RAMH), respectively. The neuroinhibitory effect of adenosine and RAMH was augmented in the presence of the N-type Ca(2+) channel blocker, omega-conotoxin GVIA but unaffected by the L-type Ca(2+) channel blocker, nifedipine. The irreversible adenylyl cyclase inhibitor, MDL-12330A, potentiated the action of both adenosine and RAMH. Conversely, neither agonist was affected by the cAMP phosphodiesterase III and IV inhibitors, SKF-95654 and Ro-20-1724, respectively, or the cAMP antagonist, (R(p))-adenosine 3',5'-cyclic monophosphorothioate triethylamine. The neuromodulatory effect of adenosine, only, was potentiated by the cGMP phosphodiesterase V inhibitors, SKF-96231 and 1,3-dimethyl-6-(2-propoxy-5-methanesulfonylamidophenyl)- pyrazolo[3, 4-d]pyrimidin-4-(5H)-one but was unmodified by the cGMP analog, 8-bromo-cGMP or the guanylyl cyclase inhibitors, N-methylhydroxylamine and 1H-[1,2,4]oxadiazolo[4, 3-a]quinoxaline-1-one (ODQ). N-Methylhydroxylamine reduced, and ODQ potentiated, the inhibitory action of H(3)-receptor activation, but 8-bromo-cGMP was without effect. The study suggests that presynaptic A(1)- and H(3)-receptors inhibit cholinergic neurotransmission in the guinea pig ileum by limiting the availability of intraneuronal Ca(2+) via inhibition of N-type Ca(2+) channels. The balance of evidence does not support the involvement of the adenylyl cyclase/cAMP or guanylyl cyclase/cGMP systems.

An investigation into the effect and mechanisms of action of nicotine in inflammatory bowel disease.

OBJECTIVE AND DESIGN: To determine the effect of nicotine on colonic inflammation in the trinitrobenzenesulphonic acid (TNBS) model of inflammatory bowel disease in comparison with sulphasalazine. MATERIALS: Male Wistar rats were used for the in-vivo and ex-vivo studies. In-vitro studies were performed using human leukemia peripheral blood monocyte cells (THP-1 cells) grown in continuous culture. TREATMENT: Rats were given access to either nicotine (5 or 100 microg/mL) or sulphasalazine (375 microg/mL) in their drinking water for 10 or 2 days respectively before and 3 days after TNBS administration. THP-1 cells were treated with nicotine (10(-14) to 10(-11) M) for 2 h before and after stimulation with 3 microg/mL lipopolysaccharide (LPS). METHODS: Inflammation in the TNBS model was assessed by measuring the tissue myeloperoxidase activity, leukotriene B4 concentration, inducible nitric oxide protein expression, the ex-vivo production of tumour necrosis factor alpha (TNFalpha), macroscopic damage score, plasma corticosterone levels and by a qualitative histological evolution. The effect of nicotine on TNFalpha production in LPS stimulated THP-1 monocyte cells in-vitro was also determined. Statistical comparisons were made using the Mann-Whitney U-test for the macroscopic damage score and an ANOVA for all other parameters. RESULTS: TNBS treated rats given access to 100 microg/mL nicotine in their drinking water had a marked reduction in several of the markers of inflammation compared to control TNBS treated rats, but a greater reduction was found at 5 microg/mL nicotine or 375 microg/mL sulphasalazine, the latter producing comparable reductions in inflammation to the low dose nicotine. Nicotine also caused a significant reduction in TNFalpha release from THP-1 cells. CONCLUSIONS: Nicotine reduced inflammation in the TNBS model of colonic damage confirming the use of nicotine in IBD although the choice of dose requires further investigation. The mechanism of action of nicotine does not involve increased corticosterone levels, but may be a consequence of a reduction in TNFalpha or leukotriene B4 production.

Topical and intravenous administration of trefoil factors protect the gastric mucosa from ethanol-induced injury in the rat.

BACKGROUND: hTFF2 and pTFF2 (formerly PSP and hSP, respectively) are members of the trefoil factor family (TFF) and are distributed throughout the gastrointestinal tract in both normal and diseased tissue. Trefoil factors have been shown to exert a mucosal protectant and/or healing role in a number of animal models but controversy exists surrounding this property in relation to their dose and route of administration. AIM: To investigate the effects of topically applied and intravenously infused trefoil factors (hTFF2 and pTFF2) and prostaglandin E2 on ethanol-induced gastric mucosal damage in rats. METHOD: A gastric chamber preparation in the anaesthetized rat was used. Injury was caused by exposing the gastric mucosa to absolute ethanol for 1 min. Trefoil factors or prostaglandin E2 were administered either intravenously or topically before and after the introduction of absolute ethanol onto the gastric mucosa. Damage was assessed by measurement of gastric mucosal Na+ leakage and area of macroscopic injury. RESULTS: Like prostaglandin E2, intravenous administration of hTFF2 and pTFF2 reduced both the gastric mucosal Na+ leakage and the mean area of damage caused by ethanol. Similarly, treatment of the gastric mucosa with topical application of hTFF2 at doses of 120 microg/kg and above reduced the Na+ leakage and the area of damage. pTFF2 at 120 microg/kg and 1.2 mg/kg applied topically produced a marked reduction in total area of damage. CONCLUSION: Intravenously infused hTFF2 and pTFF2 protect the gastric mucosa from ethanol-induced damage in the anaesthetized rat. In addition, topical application of trefoil factors also was effective at protecting the gastric mucosa from injury at doses lower than previously reported.

The effect of an inhibitor of matrix metalloproteinases on colonic inflammation in a trinitrobenzenesulphonic acid rat model of inflammatory bowel disease.

BACKGROUND: Recent publications have reported that matrix metalloproteinases (MMPs) are expressed in colonic tissue taken from ulcerative colitis and Crohn's disease patients. AIM: To evaluate the effects of a matrix metalloproteinase inhibitor, marimastat, on colonic inflammation in experimental colitis induced by trinitrobenzenesulphonic acid (TNBS)-ethanol in the rat. METHODS: Rats were dosed (by mouth) for 7 days (b.d.) with either sulphasalazine (50 mg/kg), marimastat (40 mg/kg) or vehicle. TNBS-ethanol was administered rectally on the 4th day of dosing. On the last day of dosing, colons were removed and assessed for inflammation using myeloperoxidase activity, production of soluble TNFalpha (tumour necrosis factor alpha), clinical score and histological assessment. In addition, the bioavailability and effect of marimastat on a range of MMPs were assessed in-vitro. RESULTS: In this study we have confirmed that marimastat is a broad spectrum MMPI with a bioavailability of 5%. TNBS rats dosed with sulphasalazine had a significantly lower (P < 0.05) myeloperoxidase activity, TNFalpha production and a markedly lower clinical score. Similarly, rats dosed with marimastat had a significantly lower (P < 0.05) myeloperoxidase activity and clinical score, but the TNFalpha production was not significantly reduced. CONCLUSIONS: Dosing rats with TNBS-induced colitis using sulphasalazine or marimastat produced a significant reduction in tissue injury and inflammation.

Moral orientation of elderly persons: considering ethical dilemmas in health care.

Knowledge about moral development and elderly persons is very limited. A hermeneutical interpretative study was conducted with healthy elderly persons (n = 20) in order to explore and describe their moral orientation based on the paradigms of justice (Kohlberg) and care (Gilligan). The types of moral reasoning, dominance, alignment and orientation were determined. All but one participant included both types of reasoning when discussing an ethical conflict. None of the men's moral reasoning was dominated by caring, but justice dominated the reasoning of four women. The implications for ethical decision-making and future research are discussed.

Evidence for a role for nitric oxide in relation of the frog oesophageal body to electrical field stimulation.

1. Electrical field stimulation (EFS) (1-10 Hz, 30 V, 2 ms) of frog oesophageal body strips resulted in frequency-dependent non-adrenergic, non-cholinergic (NANC) relaxations. 2. Tetrodotoxin (TTX) (10(-6)-10(-5) M) had no effect on EFS evoked relaxations with a 2 ms pulse width. At a pulse width of 0.5 ms only the responses to the highest frequency (10 Hz) were significantly inhibited by TTX at 10(-5) M. Relaxation at 2 ms pulse width were unaffected by omega-conotoxin (10(-6) M), nifedipine (10(-6) M) or cobalt (5 x 10(-4) M). 3. NG-nitro-L-arginine (L-NOARG) (10(-6)-10(-4) M), a nitric oxide synthase (NOS) inhibitor, caused a concentration-dependent inhibition of the EFS-induced NANC relaxant responses. The inhibitory effect of L-NOARG was both prevented and reversed by L-arginine but not D-arginine (5 x 10(-3) M). 4. The phosphodiester type V inhibitor (PDE V), SK&F 96231 (10(-7)-10(-4) M), caused a concentration-dependent potentiation of both the percentage relaxation and the duration of the relaxant responses to EFS. 5. ODQ (10(-7)-10(-5) M), a guanylate cyclase inhibitor, produced a concentration-dependent inhibition of EFS-evoked NANC relaxations. 6. Oxyhaemoglobin (10(-6) M), which binds nitric oxide (NO), inhibited NANC relaxations to EFS. 7. The NO donor sodium nitroprusside (SNP) (10(-8)-10(-4) M) produced a concentration-dependent inhibition of evoked tone. L-NOARG (10(-4) M) had no effect on the SNP evoked relaxations. Preincubation with oxyhaemoglobin (10(-6) M) caused a reduction in the SNP (10(-6)-10(-5) M) induced relaxations. 8. These results suggest NO is the relaxant transmitter of the frog oesophageal body and the source of NO may be non-neuronal.