Evaluation of epidermal growth factor receptor mutation status in serum DNA as a predictor of response to gefitinib (IRESSA)

The aim of this study was to evaluate the usefulness of EGFR mutation status in serum DNA as a means of predicting a benefit from gefitinib (IRESSA) therapy in Japanese patients with non-small cell lung cancer (NSCLC). We obtained pairs of tumour and serum samples from 42 patients treated with gefitinib. EGFR mutation status was determined by a direct sequencing method and by Scorpion Amplification Refractory Mutation System (ARMS) technology. EGFR mutations were detected in the tumour samples of eight patients and in the serum samples of seven patients. EGFR mutation status in the tumours and serum samples was consistent in 39 (92.9%) of the 42 pairs. EGFR mutations were strong correlations between both EGFR mutation status in the tumour samples and serum samples and objective response to gefitinib (P<0.001). Median progression-free survival time was significantly longer in the patients with EGFR mutations than in the patients without EGFR mutations (194 vs 55 days, P=0.016, in tumour samples; 174 vs 58 days, P=0.044, in serum samples). The results suggest that it is feasible to use serum DNA to detect EGFR mutation, and that it's potential as a predictor of response to, and survival on gefitinib is worthy of further evaluation.

Long-term follow-up of 5 patients with intracranial germinoma initially treated by chemotherapy alone

BACKGROUND

High rates of overall- and event-free survival have been reported in patients with intracranial germinoma treated by radiotherapy. We report the long-term results after treatment initially with chemotherapy, but without radiation.

PATIENTS AND METHOD

Five patients with an intracranial germinoma were treated with 2 cycles of etoposide and cisplatin, without radiotherapy. All achieved complete remission; 3 suffered recurrence within 2 years and were again treated with 2 cycles of etoposide and cisplatin followed by radiotherapy.

RESULTS

At long-term follow-up, each of the 5 patients was in complete remission without further recurrence. Each patient with a neurohypophyseal germinoma who presented with endocrinopathy had initially recovered endocrinological function.

CONCLUSION

In a patient with a germinoma chemotherapy, and restriction of radiation to those with recurrence may allow restoration of hypophyseal function damaged by the intracranial germinoma without compromising long term survivial.

Complete Atrioventricular Block Associated with Lymphocytic Myocarditis of the Atrioventricular Node in Two Young Adult Dogs

A histological investigation of the atrioventricular (AV) conduction system was performed in two young adult dogs with complete AV block. In both cases, infiltration of lymphocytes and plasma cells into the AV node and loss and disappearance of the conduction fibres were observed. Such inflammatory lesions of the AV conduction system were associated with complete AV block. The aetiology of these changes and the cause of its location at the AV node were not elucidated.

Role of intercellular adhesion molecule-1 in a murine model of toluene diisocyanate-induced asthma

BACKGROUND

Adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) are thought to contribute to the airway inflammation and airway hyper-responsiveness (AHR) of allergic asthma. Some differences from allergic asthma have been noted, including airway neutrophilia, and the involvement of ICAM-1 in toluene diisocyanate (TDI) asthma is currently unclear.

OBJECTIVE

We utilized mice lacking ICAM-1 expression (ICAM-1(-/-)) to investigate the role of ICAM-1 in airway inflammation and AHR in TDI-induced asthma.

METHODS

Male C57BL/6J mice (ICAM-1(+/+)) and ICAM-1(-/-) mice were intranasally sensitized to TDI solution or solvent alone. Airway inflammation, AHR and cytokine secretion were assessed 24 h after challenge by TDI or solvent. The production of antigen-specific IgG and IgE by TDI sensitized and non-sensitized mice was determined.

RESULTS

TDI challenge to ICAM-1(+/+) mice induced an increase in airway inflammatory cell numbers, AHR and cytokine secretion of TNF-alpha, macrophage inflammatory protein-2 (MIP-2), IL-4, IL-5 and IFN-gamma into the bronchoalveolar lavage fluid. All these pathophysiological changes were reduced in ICAM-1(-/-) mice. Serum levels of TDI-specific IgG and IgE of ICAM-1(-/-) and ICAM-1(+/+) mice were comparable.

CONCLUSION

These results suggest that ICAM-1 plays an essential role in airway inflammation and AHR in TDI-induced asthma.

Immature platelet fraction for prediction of platelet engraftment after allogeneic stem cell transplantation

Platelet regeneration represents an important and separate element in the engraftment process for allogeneic stem cell transplantation. Fully automated flow cytometry using blood cell counters now allows reliable quantification of reticulated platelets, expressed as the immature platelet fraction (IPF). We studied the kinetics of IPF in six patients grafted with allogeneic peripheral blood stem cell transplantation (PBSCT), 12 patients with bone marrow transplantation (BMT) and seven patients with cord blood transplantation (CBT). Preconditioning therapy caused an immediate and rapid fall in tri-lineage hematopoiesis. IPF rose transiently above 3% after a mean duration of 11 days post-PBSCT, 18 days post-BMT and 19 days post-CBT. This was 1, 4 and 13 days earlier than platelet engraftment, respectively. A linear correlation model showed a close association between the rise of IPF and tri-lineage engraftment after transplantation. IPF counting may thus provide an accessible measure of thrombopoietic activity, leading to early evaluation of marrow function and allowing monitoring of platelet regeneration.

A Histological Study of the Cardiac Conduction System in Canine Cases of Mitral Valve Endocardiosis with Complete Atrioventricular Block

The cardiac conduction system was examined histologically in four canine cases of endocardiosis of the mitral valve (MV) with complete atrioventricular (AV) block. In all cases, moderate to severe reduction of the conduction fibres due to fibrous or fibro-fatty replacement was observed in the penetrating and branching portions of the AV bundle. In addition, degenerative and fibrotic lesions were commonly seen at the upper portions of the left and right bundle branches. These changes in the AV conduction system were associated with marked degeneration and fibrosis of the base of the central fibrous body and the upper part of the ventricular septum. The degenerative and sclerotic changes of the AV junctional region, affecting the AV bundle and bundle branches, were qualitatively similar to those in age-matched control dogs, but were more severe. It is possible that the pathological process occurred as a result of ageing and may have been exaggerated or accelerated by the abnormal mechanical forces created by excessive motion of the prolapsed MV and the long-term haemodynamic stresses of mitral regurgitation, resulting in interruption of the AV conduction system to produce complete AV block. Conduction abnormalities represent a possible complication in some canine cases of MV endocardiosis.

Safety and Efficacy of Foscarnet for Preemptive Therapy Against Cytomegalovirus Reactivation After Unrelated Cord Blood Transplantation

In association with the increased use of unrelated cord blood transplantation (UCBT) in adults, numerous patients have developed cytomegalovirus (CMV) reactivation concomitant with cytopenia. Although foscarnet appears to offer similar efficacy and higher safety as a preemptive therapy against CMV infection than ganciclovir, little is known about the usefulness of foscarnet in such patients. Foscarnet was administered as preemptive therapy against CMV antigenemia in 10 UCBT recipients who were unable to receive ganciclovir due to cytopenia or poor response to ganciclovir. Fatal CMV disease developed in one patient, whereas CMV antigenemia resolved without progression to CMV disease in the remaining nine patients. Foscarnet was well tolerated without serious hematotoxicity and was not discontinued due to adverse events in any patient. Foscarnet represents a safe and effective agent for preemptive therapy against CMV infection and may offer a feasible alternative to ganciclovir in UCBT recipients.

Reduced-intensity unrelated cord blood transplantation for treatment of metastatic renal cell carcinoma: first evidence of cord-blood-versus-solid-tumor effect

We report a 69-year-old man with cytokine-resistant metastatic renal cell carcinoma treated with reduced-intensity unrelated cord blood transplantation. The patient achieved durable donor engraftment with minimal graft-versus-host disease. The patient showed regression of metastatic disease, providing the first evidence of a graft-versus-tumor effect on a solid tumor resulting from cord blood graft.

Mismatch of minor histocompatibility antigen contributes to a graft-versus-leukemia effect rather than to acute GVHD, resulting in long-term survival after HLA-identical stem cell transplantation in Japan

We determined the alleles of five polymorphic molecules including HA-1 and four adhesion molecules for 106 patients transplanted with HLA-identical stem cell grafts and investigated the association of mismatches as correlates of relapse and graft-versus-host disease (GVHD). All 106 recipients underwent stem cell transplantation (SCT) after myeloablative conditioning between 1985 and 2002. Risk status of disease at SCT was standard (n=63) and high (n=42). After SCT, 36, 49 and 33 developed acute GVHD, chronic GVHD and relapsed, respectively. Our patients relapsed at rates of 16.7 and 38.6% with one or more and without incompatibilities (P=0.013). The relapse rates of patients with CD62L, CD31 codon 563, CD31 codon 125, HA-1 and CD49b incompatibilities were 5.9, 11.8, 15.4, 16.0 and 33.3%, respectively. The frequency of acute GVHD did not differ regardless of incompatibilities. In standard-risk group, the accumulated relapse rates of 19 and 44 patients with and without minor histocompatibility antigen incompatibility were 22% and unexpectedly 66%, respectively (P=0.02). The probability of 12-year survival was 88% in the former and 66% in the latter patients (P=0.03). Our data suggest that incompatibility of CD62L, CD31 codon 563 and CD31 codon 125 contributes to a graft-versus-leukemia effect rather than to GVHD, resulting in prolonged survival after HLA-identical SCT.

Distinct telomere length regulation in premalignant cervical and endometrial lesions: implications for the roles of telomeres in uterine carcinogenesis

Mouse models show that progressive shortening of telomeres with ageing causes chromosomal instability, which can lead to the initiation of cancer. However, it is unclear what roles telomere shortening plays in human carcinogenesis. The present study has investigated the involvement of telomere dynamics in uterine carcinogenesis. Using telomere-FISH (telo-FISH) assays, telomere lengths in premalignant and malignant cervical and endometrial lesions were measured and compared with chromosomal arm loss or gain. Telo-FISH signals were visualized with Cy3-labelled telomere-specific probes and presented as telomere intensity (TI). Early-stage cervical intraepithelial neoplasias (CINs), especially CIN2, had significantly shorter telomeres than corresponding normal squamous epithelia (p = 0.019), together with increased rates of chromosomal arm loss/gain (p < 0.001). Cervical cancers had relatively short telomeres, but they also showed greater heterogeneity than other sampled tissues, including those with long telomeres. In contrast, there was no significant difference between the telomere length of normal endometrium and of endometrial hyperplasia and endometrial cancer. There was no significant difference in the rate of chromosomal arm loss/gain between normal endometrium and endometrial hyperplasia. These findings suggest that progressive shortening of telomeres occurs in CIN, in association with chromosomal instability, which may play critical roles in cervical carcinogenesis. In contrast, endometrial hyperplasias have relatively stable telomeres without widespread chromosome alteration, implying that endometrial carcinogenesis involves mechanisms distinct from those of cervical carcinogenesis, possibly including microsatellite instability.

Ambroxol for the prevention of acute upper respiratory disease

Although acute upper respiratory diseases (AURDs) such as common cold and influenza are common, few interventions have been proven to be effective in their prevention and treatment. The aim of this study was to assess the efficacy of ambroxol for preventing AURD. Fifty-four patients were randomly divided into 3 groups: a rebamipide (non-mucoactive drug) group (300 mg/day), carbocisteine group (1500 mg/day) and ambroxol group (45 mg/day). The study was divided into 2 terms, the first half-year (summer season) and the second half-year (winter season). In the preceding winter, only 19.5% of the patients had been vaccinated against influenza viruses (flu). The primary goal of this study was to evaluate the effectiveness of mucoactive drugs in decreasing the frequency of AURD. Treatment with ambroxol, but not carbocisteine, significantly reduced the median number of AURD episodes (P=0.0049 vs. rebamipide). Thirty-three patients without vaccination against flu were assessed especially during the second half-year. Treatment with ambroxol also significantly reduced the median number of AURD episodes in this assessment (P=0.0028 vs. rebamipide in the second half-year). In conclusion, ambroxol may be useful for preventing AURD.

Propofol acts at the sigma-1 receptor and inhibits pentazocine-induced c-Fos expression in the mouse posterior cingulate and retrosplenial cortices

BACKGROUND

The sigma-1 receptor is functionally linked with psychotomimetic effects of various drugs. A sigma-1 receptor agonist enhances bradykinin-induced intracellular Ca(2+) concentration ([Ca(2+)]i) increase and induces c-Fos expression in a part of the brain. The aim of this study was to investigate the effects of several intravenous anaesthetics on the sigma-1 receptor.

METHODS

First, using Wistar rat brains, (+)[(3)H]SKF-10,047, a selective sigma-1 receptor agonist was displaced by propofol, dexmedetomidine, droperidol, and thiopental. Second, Fura-2 loaded NG-108 cells were incubated with (+)pentazocine, a selective sigma-1 receptor agonist, and propofol and then its fluorescence was observed after stimulation with bradykinin. Third, male ICR mice received Intrafat or propofol intraperitoneally (i.p.), followed by pentazocine i.p. Brain slices were prepared and Fos-like immunoreactivity was detected using an immunohistochemical method. results: Propofol, droperidol, and dexmedetomidine displaced (+)[(3)H]SKF-10,047 binding in a concentration-dependent manner with Ki50s of 10.2 +/- 0.6, 0.17 +/- 0.03, 5.73 +/- 1.2 microM, respectively. Thiopental sodium was practically ineffective. Propofol produced a statistically significant reduction in the maximal binding capacity (Bmax) but did not affect the dissociation constant (K(d)). (+)Pentazocine significantly enhanced bradykinin-induced [Ca(2+)]i increases, but propofol did not affect it. Pentazocine induced marked Fos-LI positive cells in the posterior cingulate and retrosplenial cortices (PC/RS), which was significantly reduced by propofol.

CONCLUSIONS

These results suggest that propofol may be a sigma-1 receptor antagonist, and that various effects of propofol on the brain may be mediated, at least partly, by the sigma-1 receptor.

Predictive and prognostic impact of plasma vascular endothelial growth factor levels in non-small-cell lung cancer patients treated with gefitinib

13030

Background: In non-small cell lung cancer (NSCLC), sensitivity to gefitinib is associated with activating mutations of the epidermal growth factor receptor (EGFR). Tumor samples obtained for diagnosis of NSCLC are limited and often unsuitable for analysis of mutations. Other biomarkers are thus needed. We previously reported that serum vascular endothelial growth factor (VEGF) levels were significantly lower in responders to gefitinib than non-responders. To assess levels of circulating VEGF as a predictive and prognostic marker of gefitinib treatment in NSCLC patients, we examined the associations between plasma VEGF levels before gefitinib treatment and clinical outcome. Methods: Eighty four NSCLC patients treated with gefitinib were enrolled into this investigation. Plasma VEGF levels were measured in blood samples before gefitinib administration. Patients were grouped according to VEGF level around a cut-off of 80.7 pg/ml, based on results from normal controls. Response to gefitinib was judged using RECIST guidelines. Time to progression (TTP) and overall survival (OS) following gefitinib treatment were calculated using Kaplan-Meier methods. Groups were compared using log-rank test. We evaluated the immunohistochemical expression of VEGF and EGFR mutations in tumor samples from 37 patients. Results: Response rate was significantly higher with low VEGF level than with high VEGF level (p = 0.0010). Multivariate analysis for response to gefitinib including sex, histology, smoking status, performance status and plasma VEGF level identified only low VEGF level as predictive of response to gefitinib. Low VEGF level was also correlated with prolonged median TTP (4.1 months vs. 1.1 months, p = 0.0081) and OS (11.1 months vs. 5.4 months, p = 0.0290). Multivariate analysis for survival revealed low VEGF level as associated with prolonged TTP (p = 0.0081) and OS (p = 0.0708). Plasma VEGF level was not associated with either VEGF expression or EGFR mutations of tumor tissue. Conclusions: Our results suggest that plasma VEGF levels before gefitinib treatment are predictive of response to gefitinib and prognostic of patients who receive gefitinib.

[Table: see text]

Correlation between epidermal growth factor receptor gene status and clinical outcome of gefitinib in Japanese patients with non-small cell lung cancer

7192

Background: Epidermal growth factor receptor (EGFR) gene amplification and mutation have been reported to be predictors of response to EGFR inhibitors. We evaluated EGFR gene copy number and mutations in biopsy samples of non-small cell lung cancer (NSCLC) treated with gefitinib (G) and analyzed the correlation between gene status and clinical outcome. Methods: EGFR gene copy numbers in biopsy samples were evaluated using FISH and categorized as described by Cappuzzo et al. We also performed mutational analysesof exons 18, 19 and 21 of EGFR by PCR and direct sequencing. Response was judged using the RECIST guidelines. Time to progression (TTP) and overall survival (OS) were calculated and evaluated by the Kaplan-Meier method. Groups were compared using the log-rank test. Risk factors associated with survival were evaluated using Cox proportional hazards regression modeling and multivariable analysis. Results: Of 59 patients (pts) enrolled in this investigation, 24 pts (41%) were female and 21 pts (35%) had never smoked. The most common histological subtype was adenocarcinoma (73%) and 36 pts (61%) had good PS 0–1. Gene copy numbers could be analyzed in 54 pts. Gene amplification was observed in 21 pts, high polysomy in 5 pts, low polysomy in 18 pts, low trisomy in 5 pts and disomy in 5 pts. FISH positivity was observed in 26 pts (48%). EGFR mutations were detected in 18 pts (31%); point mutations in exon 21 were observed in 5 pts, in-frame deletions in exon 19 in 12 pts, a point mutation in exon 18 in 1 pt. Response rate in pts with EGFR mutations was significantly higher than in pts without mutations (56% vs. 15%, p = .0011). Response rate in FISH-positive pts was 31% and that in FISH-negative pts was 21%, the association with response was not significant. EGFR mutations were also correlated with improved TTP (median 8.3 m vs. 1.8 m, p = .0014) and OS (median 18.8 m vs. 6.4 m, p = .0059). There were no significant differences in TTP and OS based on FISH positivity. On multivariable analysis, EGFR mutations remained significantly associated with improved TTP and OS. Conclusions: Our results suggest that EGFR mutations are a better predictor of clinical benfit of G when compared with gene copy number in Japanese NSCLC pts.

[Table: see text]

Analysis of corneal inflammation induced by cauterisation in CCR2 and MCP-1 knockout mice

AIM

To elucidate the role of CCR2/MCP-1 in corneal inflammation.

METHODS

A cauterisation induced corneal inflammation model was used. The corneas were cauterised with silver nitrate in CCR2 knockout (KO) mice, MCP-1 KO mice, and control mice. Clinical signs such as corneal oedema and opacity were examined 96 hours after cauterisation and the phenotypes of the cells infiltrating the cornea were analysed by flow cytometry. Corneal inflammation in neutrophil depleted mice was also analysed.

RESULTS

After cauterisation both CCR2 KO and MCP-1 KO mice showed the same levels of corneal oedema and opacity as control mice. Flow cytometry revealed that in control mice most of the infiltrating cells were neutrophils and macrophages, whereas in both CCR2 KO mice and MCP-1 KO mice, the number of macrophages infiltrating the cornea were markedly reduced. However, prominent infiltrates of neutrophils were still observed in the cornea in CCR2 KO mice and MCP-1 KO mice. The depletion of neutrophils significantly reduced the oedema and opacity induced in the cornea by cauterisation.

CONCLUSION

The CCR2 and MCP-1 molecules are not essential for cauterisation induced corneal inflammation. Neutrophils, rather than migrated macrophages, are the final effector cells involved in inducing inflammation in this model.

Sivelestat, a specific neutrophil elastase inhibitor, prevented phorbol myristate acetate-induced acute lung injury in conscious rabbits

The in vivo contribution of neutrophil elastase (NE) in phorbol myristate acetate (PMA)-induced acute lung injury has so far been unclear. This study examined the role of NE in PMA-induced acute lung injury in conscious rabbits, using a specific NE inhibitor, sivelestat sodium hydrate (Sivelestat). A single bolus injection of PMA (40 microg/kg) caused acute lung injury as indicated by an increase in protein concentration and hemorrhage in bronchoalveolar lavage fluid (BALF) 4h after PMA injection. These changes were associated with mild decrease in arterial oxygen pressure and peripheral white blood cell and platelet. When continuously infused starting 1h before and ending 4h post-PMA injection, Sivelestat at 3-30 mg/kg/h that are able to inhibit rabbit NE activity by 60-90%, dose-dependently attenuated both PMA-induced hemorrhagic pneumonitis and the increase in protein concentration in BALF without affecting myeloperoxidase activity in the lung. Histopathological study indicated that sivelestat (30 mg/kg/h) markedly attenuated lung histopathological changes, alveolar hemorrhage and white blood cells migration with evidence of inhibition of NE activity in BALF. These results suggest that NE plays a significant role in PMA-induced acute lung injury and further supports the importance of this enzyme in acute lung injury.

Antimyeloma effects of a novel synthetic retinoid Am80 (Tamibarotene) through inhibition of angiogenesis

In multiple myeloma (MM), the interaction between myeloma cells and bone marrow microenvironment has an important role in the pathogenesis of MM. We first examined the inducing effect of myeloma cells on migration of human umbilical vein vascular endothelial cells (HUVECs). Five myeloma cell lines produced varying amounts of VEGF, and migration of HUVECs was induced by coculture with myeloma cells. We next examined the inhibitory effect of a novel synthetic retinoid Am80 (Tamibarotene) on both myeloma cells and HUVECs. Am80 is specific for the retinoic-acid receptor-alpha/beta, and has therapeutic effects in all-trans retinoic acid resistant acute promyelocytic leukemia. Am80 slightly inhibited the growth of both myeloma cells and HUVECs, and remarkably inhibited the growth of HUVECs stimulated by VEGF. Am80 showed little growth inhibition of bone marrow stromal cells (BMSCs), but it markedly inhibited migration of HUVECs by cocultured myeloma cells. Am80 inhibited VEGF-induced phosphorylation of VEGF receptor. In addition, VEGF-induced formation of tube-like structures in vitro and neovascularization in mouse corneas were significantly inhibited by Am80. These findings clearly demonstrate that Am80 is a potential inhibitor of angiogenesis caused by the interaction between vascular endothelial cells and myeloma cells, and might be a useful therapeutic agent against MM.

Selective inducible nitric oxide synthase inhibition attenuates organ dysfunction and elevated endothelin levels in LPS-induced DIC model rats

We examined the role of nitric oxide (NO) produced by an inducible isoform of NO synthase (iNOS) using N[6]-(iminoethyl)-lysine (L-NIL), a selective iNOS inhibitor, in the rat model of lipopolysaccharide (LPS)-induced disseminated intravascular coagulation (DIC) and investigated changes in organ function, plasma levels of NOX (metabolites of NO) and endothelin. We induced experimental DIC by the sustained infusion of 30 mg kg(-1) LPS for 4 h via the tail vein. We then investigated the effect of L-NIL (6 mg kg(-1), from - 0.5 to 4 h) on LPS-induced DIC. Blood was withdrawn at 4 and 8 h, and all four groups (LPS with or without L-NIL at 4 and 8 h) consisted of eight rats. Three of the animals in the 8-h LPS group died, and we examined blood samples from five rats in this group. None of the other rats died. The LPS-induced elevation of creatinine, alanine aminotransferase, glomerular fibrin deposition and plasminogen activator inhibitor was significantly suppressed by L-NIL coadministration, although L-NIL did not affect the platelet count, fibrinogen concentration or the level of thrombin-antithrombin complex. Moreover, plasma levels of the D-dimer that reflect the lysis of cross-linked fibrin were significantly increased by L-NIL coadministration in the LPS-induced DIC model. Plasma levels of NOX and endothelin were obviously increased by LPS infusion. However, both levels were significantly suppressed in the LPS + L-NIL group, when compared with the LPS group. Although mean arterial pressure (MAP) was significantly decreased between 2 and 8 h compared with the control in the LPS group, this depression was significantly attenuated in the LPS + L-NIL group. Our results suggest that NO induced by iNOS contributes to hypotension (depressed MAP), the progression of hepatic and renal dysfunction, microthrombus deposition and elevated endothelin levels in the rat model of LPS-induced DIC.

Effects of propofol and thiopental on the central nervous system during nociceptive stimulation in cats

PURPOSE

Nociceptive stimulation may increase central nervous system (CNS) activity during anesthesia. However, it is not known whether propofol and thiopental have a similar inhibitory effect on the CNS during nociceptive stimulation. Therefore, we compared the antinociceptive effects of propofol and thiopental in cats.

METHODS

In 12 cats, anesthesia was induced with 4% halothane in oxygen and maintained with 0.5% halothane in oxygen. The cortical electroencephalogram (EEG) and the electrical activity from the midbrain reticular neurons (R-MUA) were measured before and after sciatic nerve stimulation. The cats were then allocated to receive cumulative doses of either propofol (n = 6) or thiopental (n = 6) i.v. at 5-min intervals. Two minutes after each dose, the cortical EEG and the R-MUA were compared before and after sciatic nerve stimulation.

RESULTS

Propofol and thiopental depressed the basal R-MUA to a similar degree at each dose. Sciatic nerve stimulation increased the R-MUA, and there were no differences in the maximum R-MUA values between propofol and thiopental. The cortical EEGs after each dose of anesthetic without stimulation showed similar patterns, and the patterns of change with stimulation were also similar for these two anesthetics.

CONCLUSION

Propofol and thiopental have similar antinociceptive effects in cats.

Attenuating effect of H+K+ATPase inhibitors on airway cough hypersensitivity induced by allergic airway inflammation in guinea-pigs

BACKGROUND

Gastrooesophageal reflux (GER) is a frequent cause of chronic cough. Several investigators have indicated that inhibitors of H(+)K(+)ATPase (proton pump inhibitors; PPIs) could relieve coughing via inhibition of acid reflux. However, we considered that PPIs might directly inhibit increased cough reflex sensitivity.

OBJECTIVE

The present study was designed to examine whether PPIs directly inhibit antigen-induced increase in cough reflex sensitivity and to elucidate the mechanism.

METHODS

Actively sensitized guinea-pigs were challenged with aerosol antigen (ovalbumin, OVA) and cough reflex sensitivity to inhaled capsaicin was measured 24 h later. The PPIs (omeprazole and rabeprazole) or the histamine H(2) blocker cimetidine were administered intraperitoneally 1 h before OVA challenge and before measuring cough reflex sensitivity, then bronchoalveolar lavage fluid (BALF) was immediately collected. The pH of the fluid obtained by bronchial washing was determined after examining the effect of rabeprazole on the cough response to capsaicin.

RESULTS

The number of coughs elicited by capsaicin was significantly increased 24 h after challenge with OVA compared with saline, indicating antigen-induced increase in cough reflex sensitivity. Both PPIs dose dependently and significantly inhibited antigen-induced cough hypersensitivity. Omeprazole did not influence the antigen-induced increase in the total number of cells or ratio (%) of eosinophils in BALF. Cimetidine did not affect the antigen-induced cough hypersensitivity or cellular components of BALF. The pH of the bronchial washing fluid was significantly decreased in antigen-challenged animals. Rabeprazole did not affect the antigen-induced decrease in the pH of bronchial washing fluid.

CONCLUSION

These findings show that PPIs, but not histamine H(2) blockers, can directly decrease antigen-induced cough reflex hypersensitivity, while the mechanism remains unclear.