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R W Chapman

Publications and source records attributed to R W Chapman.

At least 73 records · Page 4Linked to original sources

Eosinophils retain their granule major basic protein in a murine model of allergic pulmonary inflammation.

Accumulation of eosinophils in the lung with concomitant tissue damage are defining histopathologic features of human asthma. Through degranulation and the release of proinflammatory proteins such as major basic protein (MBP), eosinophils may perpetuate this inflammatory response. We investigated the extent of eosinophil degranulation in a murine model of allergic pulmonary inflammation. In this paradigm, the mice develop pulmonary eosinophilia, mucus hypersecretion, tissue damage, and airway edema and hyperreactivity. To evaluate the degree of eosinophil degranulation, we used a polyclonal antibody to murine MBP (mMBP) to perform dot blot analysis of bronchoalveolar lavage (BAL) cells and fluids, and immunohistochemical fluorescent analysis of lung tissue sections. After ovalbumin antigen challenge, we were unable to detect immunoreactive mMBP in the BAL fluids from either nonsensitized or sensitized mice. However, after lysis of the recoverable BAL cells, we were able to detect mMBP by immunoblot analysis, with the levels of immunoreactive mMBP directly related to the number of recoverable eosinophils. We also examined paraffin-embedded, lung tissue sections for patterns of mMBP deposition. Whereas lung sections from allergic mice revealed prominent peribronchial eosinophilia after antigen challenge, tissue sections from nonsensitized animals rarely displayed eosinophils. Despite the presence of numerous eosinophils, no immunohistologic evidence of extracellular mMBP could be found in antigen-challenged allergic mice. Furthermore, rechallenged allergic mice displayed a significant increase in the number of recruited pulmonary eosinophils but all immunoreactive mMBP was still intracellular. We conclude that the recruited pulmonary eosinophils have not substantially degranulated. These results suggest that, in this murine model of allergic inflammation, eosinophil degranulation and release of mMBP does not contribute to the observed pulmonary inflammation and airway hyperreactivity.

Animals↗

Tachykinins in the lungs.

Tachykinins are neuropeptides which regulate various biological responses, some of which are potentially important in the pathogenesis of pulmonary diseases such as asthma. Tachykinins produce their biological effects by stimulating specific tachykinin receptors (NK(1), NK(2) and NK(3)). Tachykinins have a variety of effects in the lungs. They are among the most potent bronchoconstrictor agents known and have potent effects on airway blood vessel caliber, causing vasodilation by an endothelium-dependent mechanism. Exogenously administered tachykinins (substance P, neurokinin A and neurokinin B) induce mucus secretion in most species, including humans. In addition to having effects on airway secretion, tachykinins also modulate the mucociliary clearance mechanisms of the airway. Tachykinin receptors are found on pulmonary/bronchial C fibers, and both excitatory and inhibitory effects of tachykinins on neural discharge and neurotransmitter release from these nerves have been described. Tachykinins are also involved in several reflex responses, particularly the cough reflex. Tachykinins have been implicated in the inflammatory response in the lungs and they also participate in the regulation of the immune system. A considerable body of evidence implicates tachykinins as important mediators of the neurogenic inflammatory response in a variety of pulmonary diseases. It is thus expected that tachykinin receptor antagonists will prove useful in the therapy of diseases such as asthma, allergic rhinitis and chronic bronchitis.

Journal Article↗

Anti-inflammatory activity of inhaled mometasone furoate in allergic mice.

Mometasone furoate (CAS 83919-23-7, Sch 32088) is a new inhaled corticosteroid that is being developed to treat allergic inflammatory airway disorders such as rhinitis and asthma. In this study, we investigated the effects of inhaled mometasone furoate in allergic mice that, after antigen challenge, develop an influx of eosinophils and T cells and display an increased mRNA expression of proinflammatory cytokines in the lungs. Mometasone furoate aerosol was generated from metered dose inhalers and delivered into an animal exposure chamber. The mice were exposed to mometasone furoate by nose-only inhalation at respired doses ranging from 0.5-33 micrograms/kg given 24, 18 and 2 h before aeroallergen challenge. The elevated eosinophil numbers in the bronchoalveolar lavage fluid and lung tissues of sensitized, ovalbumin challenged mice were dose-dependently inhibited by inhaled mometasone furoate. Increased numbers of Thy1+ T cells and CD4+ (T-helper) and CD8+ (T-cytotoxic) T cell subsets were seen in the bronchoalveolar lavage fluid of ovalbumin-challenged mice. Pretreatment of these animals with mometasone furoate (33 micrograms/kg) reduced the number of Thy1+ T cells and the T-helper subset. Furthermore, mometasone furoate (33 micrograms/kg) reduced the percentage of CD44+ T-helper cells (activated/memory cells) to the levels observed in non-sensitized, ovalbumin-challenged mice. There were increased levels of steady-state mRNA for interleukin-4, interleukin-5, and to a lesser extent, gamma-interferon in the lungs of sensitized mice after ovalbumin challenge and pretreatment with mometasone furoate reduced the steady-state mRNA levels of these cytokines. Our results demonstrate a potent lung anti-inflammatory effect of inhaled mometasone furoate and identify that inhibition of T cell influx, eosinophil accumulation and modulation of cytokine activity are important components of this response.

Administration, Inhalation↗

Studies on the pharmacology of the novel histamine H3 receptor agonist Sch 50971.

Experiments were performed to characterize the pharmacology of Sch 50971 ((+)-trans-4-(4(R)-methyl-3(R)-pyrolidinyl)-1H-imidazole dihydrochloride, CAS 167610-28-8), a novel histamine H3 receptor agonist. The activity of Sch 50971 was compared with that of (R)-alpha-methylhistamine (CAS 75614-87-8), a potent and moderately selective agonist of histamine H3 receptors, in a series of in vitro and in vivo assays. Sch 50971 is a high affinity, selective H3 receptor agonist in vitro and in vivo. Sch 50971 inhibits [3H]-N-alpha-methylhistamine (CAS 673-50-7) binding to the histamine H3 receptor in human brain (Ki = 5.0 nmol/l) and guinea pig brain (Ki = 2.5 nmol/l). Sch 50971 also inhibits electric field stimulated guinea pig ileum contractions (pD2 = 7.47) and decreases [3H]-norepinephrine (CAS 51-41-2) release (pD2 = 7.48) from guinea pig pulmonary artery by activation of presynaptic inhibitory H3 receptors. The in vitro effects of Sch 50971 are antagonized by low concentrations of a selective H3 antagonist, thioperamide (CAS 106243-16-7). Sch 50971 has low affinity (IC50's > 10 mumol/l) for histamine H1, dopamine D1 and D2, serotonin 5-HT2 and muscarinic cholinergic receptors. It also does not exhibit histamine H2-antagonist activity. In guinea pigs and cats, Sch 50971 exhibits in vivo H3 agonist activity. Sch 50971 inhibits sympathetic hypertension evoked by stimulation of the medulla oblongata in anesthetized guinea pigs (ED30 = 0.3 mg/kg i.v., ED30 = 1.0 mg/kg i.d.). Sch 50971 also inhibits the effects of sympathetic nerve stimulation on nasal resistance in cats. In these assays, Sch 50971 exhibits an efficacy and potency comparable to H3-agonist (R)-alpha-methylhistamine. However, under in vivo conditions, Sch 50971 does not exhibit histamine H1-mediated responses that are seen with (R)-alpha-methylhistamine at doses close to those that produce H3 effects. Therefore, Sch 50971 is a novel, potent and selective agonist of histamine H3 receptors with an improved in vitro and in vivo receptor profile selectivity compared with (R)-alpha-methylhistamine.

Airway Resistance↗

Review article: the management of primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by a progressive obliterating fibrosis of the intrahepatic and extrahepatic bile ducts. The pathogenesis of PSC is poorly understood but it is thought to be an immune-mediated disease. The optimal therapy which successfully improves symptoms, delays progression towards liver failure and transplantation and prevents the onset of cholangiocarcinoma remains elusive. Although current treatments are used to manage cholestasis and its consequences and some of the more general complications of the disease, none of the current therapeutic agents have been shown to retard and reverse the rate of disease progression. The role of cupruretics, corticosteroids, methotrexate, antifibrogenic agents and ursodeoxycholic acid in the treatment of PSC is reviewed. Orthotopic liver transplantation remains the only therapeutic option for advanced PSC but the timing of transplantation remains controversial and the possibility of recurrence of the disease in the graft is increasingly recognised. It is likely that greater insight into the pathogenetic mechanisms involved in PSC will allow therapy to be targetted more specifically at the biliary epithelium.

Chelating Agents↗

Clinical outcome of hypogammaglobulinaemic patients following outbreak of acute hepatitis C: 2 year follow up.

In 1994, an outbreak of hepatitis C virus (HCV) infection, genotype 1a, occurred in 30 hypogammaglobulinaemic patients in the UK from one batch of contaminated anti-HCV screened intravenous immunoglobulin. This study aimed to study prospectively the outcome of HCV in hypogammaglobulinaemic patients, and to assess the response to early treatment with interferon-alpha, 6 million units three times weekly for 6 months. Data were collected using standardized questionnaires. Five patients with secondary hypogammaglobulinaemia due to lymphoid malignancy were not treated and all have died of their primary malignancy. Of 25 patients with primary hypogammaglobulinaemia, one resolved HCV infection before treatment, 17 commenced on treatment, and seven declined or treatment was contra-indicated. Thirteen of 17 patients completed therapy and seven (54%) have a sustained response (normal transaminases, negative serum HCV RNA) at 6 and 12 months after treatment. Two of the 12 patients with primary hypogammaglobulinaemia, who were not treated or failed to complete treatment, have cleared the virus. Liver biopsy was performed in patients not clearing HCV and was abnormal in all. Four patients developed liver failure within 2 years, of whom three have died and one has been successfully transplanted. In conclusion, HCV can cause rapid severe liver disease in hypogammaglobulinaemic patients. Early treatment with high-dose interferon-alpha results in a high clearance of HCV.

Acute Disease↗

Sch 37224, an experimental antiallergy compound, inhibits the neuropeptide component of hyperventilation- and nicotine-induced bronchoconstriction in guinea pigs.

Sch 37224 is an experimental antiallergy compound that inhibits hyperventilation-induced bronchoconstriction (HIB) in guinea pigs and cold air bronchospasm in human asthmatics. HIB in guinea pigs may involve the release of tachykinins such as neurokinin A (NKA) and substance P (SP), and the action of Sch 37224 in this model may relate to inhibition of these neuropeptides. We studied the effect of Sch 37224 on the neuropeptide component of HIB that was enhanced in guinea pigs treated with the neutral endopeptidase inhibitors, thiorphan and phosphoramidon. Pulmonary resistance (RL) and dynamic lung compliance (CDyn) were measured in anesthetized, mechanically ventilated guinea pigs. RL and CDyn were measured at baseline (1 ml/100 g tidal volume and 50 breaths/min) and after a 10-min period of hyperventilation (1 ml/100 g, 150 breaths/min). Hyperventilation produced modest changes in RL (+41 +/- 12%) and CDyn (-12 +/- 3%) which were markedly enhanced by treatment with 3 mg/kg of either thiorphan or phosphoramidon (RL + 269 +/- 43% for thiorphan, + 292 +/- 63% for phosphoramidon and CDyn -65 +/- 3% for thiorphan, -51 +/- 13% for phosphoramidon). In the presence of thiorphan or phosphoramidon, the bronchospasm to hyperventilation was significantly reduced (> 70%) with 5 mg/kg, p.o., of Sch 37224. In other studies, the peptidergic (conducted in the presence of ipratropium bromide and phosphoramidon) bronchoconstrictor response to intravenous nicotine (1 mg/kg) was also inhibited by Sch 37224 (0.3-10 mg/kg, p.o.). However, Sch 37224 (5 mg/kg, p.o.) had no effect on the bronchoconstrictor response to intravenous NKA. These results indicate that Sch 37224 inhibits the neuropeptide component of HIB and nicotine in guinea pigs and this effect appears to be mediated by the inhibition of the release of tachykinins from airway C fibers.

Animals↗

Role of nitric oxide on eosinophilic lung inflammation in allergic mice.

Nitric oxide (NO) is an important mediator of inflammatory reactions and may contribute to the lung inflammation in allergic pulmonary diseases. To assess the role of NO in pulmonary inflammation, we studied the effect of four nitric oxide synthase (NOS) inhibitors, N-nitro-L-arginine methyl ester (L-NAME), aminoguanidine, N(G)-monomethyl-L-arginine (NMMA) and L-N6-(1-Iminoethyl) lysine (L-NIL), on the influx of eosinophils into the bronchoalveolar lavage (BAL) fluid and lung tissue of antigen-challenged allergic mice. We also analyzed lung tissues for the presence of steady state mRNA for inducible nitric oxide synthase (iNOS) and iNOS protein. Furthermore, BAL fluid and serum were analyzed for their nitrite content. B6D2F1/J mice were sensitized to ovalbumin (OVA) and challenged with aerosolized OVA. The NOS inhibitors were given 0.5 h before and 4 h after the antigen challenge. OVA challenge induced a marked eosinophilia in the BAL fluid and lung tissue 24 h after challenge. The OVA-induced pulmonary eosinophilia was significantly reduced by L-NAME (10 and 50 mg/kg, intraperitoneally [i.p.]). The inactive isomer, D-NAME (50 mg/kg, i.p.) had no effect. When mice were treated with L-NAME (20 mg/kg, i.p.) and an excess of NOS substrate, L-arginine (200 mg/kg, i.p.), the OVA-induced pulmonary eosinophilia was restored. Treatment with aminoguanidine (0.4-50 mg/kg, i.p.) also reduced the pulmonary eosinophilia. Treatment with NMMA (2-50 mg/kg, i.p.) partially reduced the eosinophilia, but L-NIL (10-50 mg/kg, i.p.), a selective iNOS inhibitor, had no effect. L-NAME had no effect on the reduction of eosinophils in the bone marrow following OVA challenge to sensitized mice. OVA challenge to sensitized mice had no effect on iNOS protein expression or iNOS mRNA in the lungs or on the levels of nitrite in the BAL fluid. These results suggest that NO is involved in the development of pulmonary eosinophilia in allergic mice. The NO contributing to the eosinophilia is not generated through the activity of iNOS nor does NO contribute to the efflux of eosinophils from the bone marrow in response to antigen challenge. It is speculated that after antigen challenge, the localized production of NO, possibly from pulmonary vascular endothelial cells, is involved in the extravasation of eosinophils from the circulation into the lung tissue.

Animals↗

Pulmonary biology of anti-interleukin 5 antibodies.

Interleukin-5 (IL-5) is a critical cytokine for the maturation of eosinophil precursors to eosinophils in the bone marrow and those eosinophils then accumulated in the lungs during asthma. We have studied anti IL-5 antibodies on allergic responses in mice, guinea pigs and monkeys and are extending this experiment into humans with a humanized antibody. In a monkey model of pulmonary inflammation and airway hyperreactivity, we found that the TRFK-5 antibody blocked both responses for three months following a single does of 0.3 mg/kg, i.v. This antibody also blocked lung eosinophilia in mice by inhibiting release from the bone marrow. To facilitate multiple dosing and to reduce immunogenicity in humans, we prepared Sch 55700, a humanized antibody against IL-5. Sch 55700 was also active against lung eosinophilia in allergic monkeys and mice and against pulmonary eosinophilia and airway hyperresponsiveness in guinea pigs. Furthermore, as opposed to steroids, Sch 55700 did not cause immunosuppression in guinea pigs. Studies with this antibody in humans will be critical to establishing the therapeutic potential of IL-5 inhibition.

Animals↗

Bronchoconstrictor and respiratory effects of neurokinin A in dogs.

Neurokinin A (NKA) is the primary bronchoconstrictor tachykinin in the lungs of several species, including humans and has been implicated as an important mediator of inflammatory lung disorders, such as asthma. In this study, we investigated the effect of NKA on airway mechanics (lung resistance, dynamic lung compliance) and respiration (tidal volume, respiratory rate) in anesthetized, spontaneously breathing, male beagle dogs. The dogs were challenged with aerosolized NKA that was delivered from a jet nebulizer to the airways through an endotracheal tube. The challenge consisted of five separate inflations of 600 ml of air/inflation over a 1-min period. Challenge with aerosolized NKA (0.1-1%) produced a dose-dependent increase in lung resistance and a decrease in dynamic lung compliance. The bronchoconstriction induced by 1% NKA peaked at 0.5 min after challenge and had a duration of approximately 5 min. Challenge with 1% NKA also reduced tidal volume and increased respiratory rate. Pretreatment of dogs with the NK-2 receptor antagonist, SR 48968 dose-dependently (1-10 mg/kg, p.o.) blocked the bronchoconstriction and respiratory responses to NKA challenge. Pretreatment with the NK1-receptor antagonist, CP 99994 (1 mg/kg, i. v.) had no effect on the increase in lung resistance and the decrease in dynamic lung compliance due to NKA challenge, but blunted the respiratory response to NKA. Pretreatment of dogs with inhaled ipratropium bromide (0.01%) slightly, but significantly reduced the increase in lung resistance due to NKA challenge but had no effect on the decrease of dynamic lung compliance or on the respiratory responses to NKA. As expected, the bronchoconstrictor response to inhaled methacholine was completely blocked by inhaled ipratropium bromide (0.01%). In conclusion, we have identified an NK2-receptor mediated bronchoconstrictor effect of NKA in dogs. Cholinergic reflexes play a small, but significant role in this response. Furthermore, both NK1 and NK2-receptors appear to be involved with the development of the rapid, shallow breathing response to NKA challenge. These results demonstrate an effect of tachykinins on airway mechanics and ventilatory reflexes in dogs.

Animals↗

Elevation of gamma delta T lymphocytes in peripheral blood and livers of patients with primary sclerosing cholangitis and other autoimmune liver diseases.

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease that is possibly an autoimmune disease. Although gamma delta T cells represent a small proportion of the total T-cell population in healthy individuals, there is evidence to suggest a role for these cells in autoimmunity. Accordingly, the aim of this study was to investigate the population of gamma delta T cells in patients with PSC, compared with other chronic liver diseases. An elevation in the percentage and absolute numbers of gamma delta T cells was found in the peripheral blood of patients with PSC (8.66% and 0.13 x 10(-6)/L [P < .01 and < .05, respectively]) and autoimmune hepatitis (AIH) (8.03% and 0.13 x 10(-6)/L [both P < 0.001]) compared with controls (4.10% and 0.06 x 10(-6)/L). We also found an elevation in the percentage and absolute numbers of gamma delta T cells in the portal areas of patients with PSC (10.55% and 4.33 [P < .001 and < .001, respectively]), AIH (7.16% and 4.55 [P = .001 and < .001, respectively]), and primary biliary cirrhosis (PBC) (5.57% and 3.49 [P = .008 and < .001, respectively]) when compared with controls (2.23% and 0.81). These findings suggest a role for gamma delta T cells in the mechanism of immune damage in autoimmune liver diseases.

Aged↗

Reflux symptom relief with omeprazole in patients without unequivocal oesophagitis.

BACKGROUND: As many as 50% of patients with reflux symptoms have no endoscopic evidence of oesophagitis. This multicentre study was designed to assess symptom relief after omeprazole 20 mg once daily in patients with symptoms typical of gastro-oesophageal reflux disease but without endoscopic evidence of oesophagitis. METHODS: Patients (n = 209) were randomized in a double-blind study to receive either omeprazole 20 mg once daily (n = 98) or placebo (n = 111) for 4 weeks. Symptoms were assessed at clinic visits and using daily diary cards, with patient-completed questionnaires providing additional data on symptoms and on psychological disturbance. RESULTS: On completion, symptom relief favoured omeprazole: 57% of patients on omeprazole were free of heartburn (vs. 19% on placebo), 75% were free of regurgitation (47%) and 43% were completely asymptomatic (14%), each with P < 0.0001. Fewer patients in the omeprazole group required alginate/antacid relief medication (P < 0.05). Symptom relief (time to first heartburn-free day) was more rapid with omeprazole (2 vs. 5 days on placebo; P < 0.01). A greater reduction in anxiety occurred in the omeprazole group (P < 0.05). CONCLUSION: Omeprazole 20 mg once daily is effective in providing relief of the symptoms typical of gastro-oesophageal reflux disease in patients with essentially normal oesophageal mucosa.

Adult↗

Outbreak of acute hepatitis C following the use of anti-hepatitis C virus--screened intravenous immunoglobulin therapy.

BACKGROUND & AIMS: Hepatitis C virus (HCV) infection has been associated with intravenous (IV) immunoglobulin (Ig), and plasma donations used to prepare IV Ig are now screened to prevent transmission. Thirty-six patients from the United Kingdom received infusions from a batch of anti-HCV antibody-screened intravenous Ig (Gammagard; Baxter Healthcare Ltd., Thetford, Norfolk, England) that was associated with reports of acute hepatitis C outbreak in Europe. The aim of this study was to document the epidemiology of this outbreak. METHODS: Forty-six patients from the United Kingdom treated with Gammagard (34 exposed and 12 unexposed to the batch) returned epidemiological questionnaires. RESULTS: Eighty-two percent of the exposed patients (28 of 34) became positive for HCV RNA. Eighteen percent of the patients (6 of 34) who had infusions with this batch tested negative for HCV RNA, but 2 of the patients had abnormal liver function and subsequently seroconverted to anti-HCV antibody positive. Twenty-seven percent of the patients (9 of 34) developed jaundice, and 79% (27 of 34) had abnormal liver transferase levels. Virus isolates (n=21), including an isolate from the implicated batch, were genotype 1a and virtually identical by sequence analysis of the NS5 region, consistent with transmission from a single source. CONCLUSIONS: Hepatitis C infection can be transmitted by anti-HCV-screened IV Ig. Careful documentation of IV Ig batch numbers and regular biochemical monitoring is recommended for all IV Ig recipients.

Acute Disease↗

Absence of antineutrophil cytoplasmic antibodies in relatives of UK patients with primary sclerosing cholangitis and ulcerative colitis.

OBJECTIVE: Perinuclear antineutrophil cytoplasmic antibodies (ANCA) have been reported in patients and relatives of patients with ulcerative colitis and primary sclerosing cholangitis, suggesting that ANCA may be a genetic marker of disease susceptibility. The reported frequency of ANCA in relatives has varied greatly, between 0 and 30%. We therefore studied the prevalence of ANCA in unaffected first-degree relatives of British patients with primary sclerosing cholangitis and ulcerative colitis. DESIGN: Thirty-six patients with ulcerative colitis, 33 with primary sclerosing cholangitis and 187 relatives were studied. Ninety-seven relatives were from the primary sclerosing cholangitis proband and 90 were from the ulcerative colitis proband. As an environmental control, 32 spouses were included: 14 from the primary sclerosing cholangitis group and 18 from the ulcerative colitis group. Eighteen healthy volunteers were additional controls. METHODS: ANCA was detected using immunoalkaline phosphatase method. RESULTS: Only 3 of 97 (3%) of the primary sclerosing cholangitis proband relatives had ANCA. One of these had ulcerative colitis, one had rheumatoid arthritis and the third systemic lupus erythematosus. Both rheumatoid arthritis and system lupus erythematosus are known to exhibit ANCA. All other sera were negative. CONCLUSION: ANCA was found only in patients with primary cholangitis and ulcerative colitis and not in their healthy first-degree relatives. ANCA is therefore not a genetic marker for increased disease susceptibility to primary sclerosing cholangitis or ulcerative colitis in the British population.

Adult↗

Increased prevalence of Listeria monocytogenes in the faeces of patients receiving long-term H2-antagonists.

BACKGROUND: Human listeriosis is an uncommon infection caused by the Gram-positive organism Listeria monocytogenes. OBJECTIVE: To investigate the effects of therapeutic gastric acid suppression on faecal isolation of L. monocytogenes and the incidence of human listeriosis. METHODS: Five stool specimens from each of 20 patients on continuous H2-antagonist therapy and two faecal samples from each of 47 healthy controls were investigated for the presence of Listeria spp. RESULTS: A higher faecal isolation rate of L. monocytogenes was detected amongst the patients (20%) compared with the controls (2.1%) (P < 0.025). All subjects with stools positive for Listeria spp. were female, this sex difference being significant in the patient group (P < 0.0036) compared with controls. No patient, however, developed listeriosis. CONCLUSION: Patients on long-term gastric acid suppressive therapy may be at increased risk of faecal carriage of L. monocytogenes.

Adult↗