Alteration in faecal bile acids, gut microbial composition and diversity after laparoscopic sleeve gastrectomy.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is a well established treatment for severe obesity and type 2 diabetes. Although the gut microbiota is linked to the efficacy of LSG, the underlying mechanisms remain elusive. The effect of LSG for morbid obesity on the gut microbiota and bile acids was assessed here. METHODS: Severely obese subjects who were candidates for LSG were included and followed until 6 months after surgery. The composition and abundance of the microbiota and bile acids in faeces were assessed by 16S ribosomal RNA sequencing, quantitative PCR and liquid chromatography-mass spectrometry. RESULTS: In total, 28 patients with a mean(s.d.) BMI of 44·2(6·6) kg/m2 were enrolled. These patients had achieved excess weight loss of 53·2(19·0) per cent and showed improvement in metabolic diseases by 6 months after LSG, accompanied by an alteration in the faecal microbial community. The increase in α-diversity and abundance of specific taxa, such as Rikenellaceae and Christensenellaceae, was strongly associated with reduced faecal bile acid levels. These changes had a significant positive association with excess weight loss and metabolic alterations. However, the total number of faecal bacteria was lower in patients before (mean(s.d.) 10·26(0·36) log10 cells per g faeces) and after (10·39(0·29) log10 cells per g faeces) operation than in healthy subjects (10·83(0·27) log10 cells per g faeces). CONCLUSION: LSG is associated with a reduction in faecal bile acids and greater abundance of specific bacterial taxa and α-diversity that may contribute to the metabolic changes.

ANTECEDENTES: La gastrectomía vertical laparoscópica (laparoscopic sleeve gastrectomy, LSG) es un tratamiento bien establecido para la obesidad grave y la diabetes tipo 2. Aunque la microbiota intestinal se ha vinculado con la eficacia de LSG, los mecanismos subyacentes siguen siendo poco conocidos. En este estudio se evaluó el efecto de LSG en la obesidad mórbida sobre la microbiota del intestino y de los ácidos biliares (bile acids, BA). MÉTODOS: Tras la aprobación del Comité ético y la obtención del consentimiento informado, los sujetos con obesidad grave que eran candidatos para LSG fueron incluidos en el estudio y seguidos durante 6 meses después de la operación. Se evaluaron la composición y abundancia de la microbiota y BA en las heces mediante secuenciación del gen 16S rRNA, PCR cuantitativa y cromatografía líquida-espectrometría de masas. RESULTADOS: En total, 28 pacientes con una mediana (rango) del IMC de 43,9 kg/m2 (35,0-61,9) fueron reclutados y a los 6 meses tras una LSG, consiguieron una pérdida del exceso de peso de 47,3% (20,7-95,1) y mejoría de las enfermedades metabólicas acompañada de una alteración en la comunidad microbiana fecal. El aumento en la diversidad α y abundancia de especies taxonómicas específicas como Rikenellaceae y Christensenellaceae, se asociaba fuertemente con niveles fecales reducidos de BA. Estos cambios se asociaban de manera positiva y significativa con la pérdida del exceso de peso y las alteraciones metabólicas. Sin embargo, el número total de bacterias fecales en los pacientes fue inferior al de los sujetos sanos (10,84 log10 células/g heces (9,46-11,35)) antes de la operación (10,26 log10 células/g heces (9,44-10,91)) y después de la misma (10,42 log10 células/g heces (9,57-10,96)). CONCLUSIÓN: LSG se asoció con menos BA fecal y mayor abundancia de especies bacterianas específicas y diversidad α lo que puede contribuir a los cambios metabólicos.

Comparison of recombinant human thrombomodulin and gabexate mesylate for treatment of disseminated intravascular coagulation (DIC) with sepsis following emergent gastrointestinal surgery: a retrospective study.

PURPOSE: Recombinant thrombomodulin (rTM) has been available in Japan since 2008, but there is concern about its association with postoperative hemorrhage. The efficacy and safety of rTM were examined in patients with disseminated intravascular coagulation (DIC) caused by a septic condition after gastrointestinal surgery. METHODS: Forty-two patients were emergently admitted to the intensive care unit after emergent gastrointestinal surgery in Kyushu University Hospital from May 2008 to April 2013. Of these patients, 22 had DIC (defined as an acute DIC score ≥ 4). All but three patients received treatment with gabexate mesylate (GM) (n = 9) or rTM (n = 10). The causes of sepsis were peritonitis with colorectal perforation, anastomotic leakage, and intestinal necrosis. Acute DIC score, sepsis-related organ failure assessment score, platelet count, and a variety of biochemical parameters were compared between rTM and GM recipients after treatment administration. RESULTS: There were no significant differences between the groups for any parameter except C-reactive protein levels. The CRP level tended to be lower in the rTM group than in the GM group. Acute DIC score in the rTM group resolved significantly earlier than that in the GM group. No patient stopped the administration of rTM because of postoperative bleeding. CONCLUSION: rTM may be an effective therapeutic drug for the treatment of septic patients with DIC following emergent gastrointestinal surgery.

Effect of laparoscopic splenectomy on portal haemodynamics in patients with liver cirrhosis and portal hypertension.

BACKGROUND: The effect of splenomegaly in patients with liver cirrhosis and portal hypertension is not fully understood. This study was designed to determine the effect of laparoscopic splenectomy on portal haemodynamics in these patients. METHODS: Patients with liver cirrhosis and portal hypertension who underwent laparoscopic splenectomy in Kyushu University Hospital from January 2006 to March 2009 were evaluated retrospectively. Correlations between splenic size and portal haemodynamics, and changes in portal haemodynamics and in levels of the vasoactive agents endothelin (ET) 1 and nitric oxide metabolites (NOx) before and 7-10 days after laparoscopic splenectomy were analysed. RESULTS: Portal venous (PV) blood flow, PV cross-sectional area and PV congestion index correlated significantly with splenic size (P < 0·050). All three were significantly reduced following splenectomy in 59 patients. The hepatic venous pressure gradient, measured in 18 patients, decreased by 25 per cent after splenectomy (P < 0·001). Portal vascular resistance was also reduced, by 21 per cent (P = 0·009). The peripheral blood concentration of ET-1 decreased from 2·95 to 2·11 pg/ml (P < 0·001), and that of NOx tended to decrease (from 29·2 to 25·0 pg/ml; P = 0·068). In hepatic venous blood, the level of ET-1 decreased from 2·37 to 1·83 pg/ml (P = 0·006), whereas NOx concentration tended to increase (from 24·5 to 30·9 pg/ml; P = 0·067). CONCLUSION: In patients with liver cirrhosis and portal hypertension, splenectomy reduced portal venous pressure. A decrease in splanchnic blood flow, by eliminating splenic blood flow, and reduction in intrahepatic vascular resistance, by normalizing hepatic concentrations of ET-1 and NOx, may both have contributed.

Characteristics of splenic CD8+ T cell exhaustion in patients with hepatitis C.

There is increasing interest in the role of T cell exhaustion and it is well known that the natural history of chronic hepatitis C virus infection (HCV) is modulated by CD8(+) T cell immunobiology. There are many pathways that alter the presence of exhaustive T cells and, in particular, they are functionally impaired by inhibitory receptors, such as programmed death-1 (PD-1) and T cell immunoglobulin and mucin domain-containing protein 3 (Tim-3). We obtained spleen, liver and peripheral blood (before and after splenectomy) lymphoid cells from 25 patients with HCV-related cirrhosis undergoing liver transplantation for end-stage disease or splenectomy for portal hypertension. In all samples we performed an extensive phenotypic study of exhaustion markers [PD-1, Tim-3, interferon (IFN)-γ) and their ligands (PD-L1, PD-L2, galectin-9] in CD8(+) T cell subpopulations (both total and HCV-specific) and in antigen-presenting cells (APC; monocytes and dendritic cells). In the spleen, total and HCV-specific CD8(+) T cells demonstrated enhanced markers of exhaustion, predominantly in the effector memory subpopulation. Similarly, splenic APC over-expressed inhibitory receptor ligands when compared to peripheral blood. Finally, when peripheral blood CD8(+) T cells were compared before and after splenectomy, markers of exhaustion were reduced in splenic CD8(+) T cells and APC. Our data in HCV-related cirrhosis suggest that CD8(+) T cells in the spleen manifest a significantly higher exhaustion compared to peripheral blood and may thus contribute to the failure to control HCV. Counteracting this process may contribute to inducing an effective immune response to HCV.

Modulation of CD4⁺ T cell responses following splenectomy in hepatitis C virus-related liver cirrhosis.

Dysfunction of T cells is a common feature in chronic persistent viral infections, including hepatitis C virus (HCV), and although hepatic and peripheral T cells have been studied extensively in chronic HCV hepatitis, the role of splenic T cell responses in such patients is poorly defined. This is an important issue, as thrombocytopenia is a complication of HCV-related liver cirrhosis (LC), due to splenic platelet sequestration and bone marrow suppression; splenectomy has been proposed to treat such patients. Herein, we studied peripheral blood mononuclear cells (PBMC) and splenic lymphoid subpopulations from a total of 22 patients, including 15 with HCV-related LC with marked thrombocytopenia treated with splenectomy, and seven controls. CD4(+) T cells from peripheral blood and spleen were isolated and phenotype and function evaluated. Splenic CD4(+) T cells in patients with LC expressed molecules associated with inhibitory signalling, including increased frequency of negative markers such as cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and programmed death 1 (PD-1) and decreased production of cytokines. Patients with LC manifest higher levels of splenic CD4(+) regulatory T cells and PD-L1- and PD-L2-expressing cells than controls. Blocking of PD-1/PD-1 ligand interaction reconstituted proliferative and cytokine responses of splenic mononuclear cells (SMC) from patients with LC. Splenectomy was followed by an increase in the ratio of interferon (IFN)-γ to interleukin (IL)-10 and a reduction of PD-1-expressing CD4(+) T cells in peripheral blood. Our data suggest that peripheral tolerance is promoted by the spleen in LC via the up-regulated expression of PD-1 ligands.

Risk factors for portal venous thrombosis after splenectomy in patients with cirrhosis and portal hypertension.

BACKGROUND: Portal venous thrombosis (PVT) is a potentially fatal complication following splenectomy. Its mechanisms and risk factors are poorly understood, especially in patients with cirrhosis and portal hypertension. This study investigated risk factors for PVT following splenectomy in such patients. METHODS: All consecutive patients with cirrhosis who underwent splenectomy in Kyushu University Hospital between 1998 and 2004 were included in this retrospective study. They were divided into two groups based on the presence or absence of postoperative PVT. Preoperative and operative factors were compared, and the relationships between formation of PVT and its independent variables were analysed. In some cases, portal venous flow was measured before and after splenectomy using duplex Doppler ultrasonography. RESULTS: PVT developed after surgery in 17 (24 per cent) of 70 patients studied. Multivariable analysis showed that increased splenic vein diameter and low white cell count were significant independent risk factors for PVT. Portal venous flow after splenectomy was greatly reduced in the PVT group, but not in patients without PVT. CONCLUSION: Large splenic vein diameter and low white cell count are independent risk factors for PVT after splenectomy in patients with cirrhosis and portal hypertension.

A foodborne outbreak of a group A streptococcal infection in a Japanese university hospital.

We describe an outbreak of foodborne tonsillopharyngitis caused by group A streptococcus (GAS), a rarely reported event that occurred during a campus orientation meeting in Japan. Of 461 students and staff members who had eaten boxed lunches during a meeting at Kitasato University, 298 developed sore throat and/or fever, and 285 underwent medical examination. Amoxicillin was prescribed when throat culture specimens yielded GAS. The attack rate was 64.6%. T-25 GAS was isolated from 150 examined persons. Of 65 patients who received amoxicillin for 3 days, GAS was eradicated before the first follow-up throat culture in 46 (70.8%) cases. Susceptibility was demonstrated to penicillins, cephalosporins, and macrolides in 86 GAS isolates obtained more than once from a given patient. GAS strains isolated at various time points were indistinguishable by pulsed-field gel electrophoresis (PFGE), and prtF1 was present. GAS strains were often difficult to eradicate because of a short initial treatment period, patient compliance problems, and the presence of prtF1.

Antitumor effect of bcl-2 antisense phosphorothioate oligodeoxynucleotides on human renal-cell carcinoma cells in vitro and in mice.

BACKGROUND AND PURPOSE: Programmed cell death is a genetically regulated pathway that is altered in many cancers. This process is, in part, regulated by the bcl-2 oncogene. Antisense oligodeoxynucleotides (ODNs) targeted to specific oncogenes have been used with some therapeutic success in animal models of leukemia and melanoma cells and human Hodgkin's lymphoma. We evaluated the effects of antisense ODNs targeted to the bcl-2 oncogene on the proliferation of human renal-cell carcinoma (RCC) cells in vitro and on the growth of human RCC xenografts in BALBc nude (nu/nu) mice. MATERIALS AND METHODS: Expression bcl-2 mRNA in five RCC cell lines (ACHN, Caki-1, RCZ, RCW, and OS-RC-2) was analyzed by reverse transcriptase-polymerase chain reaction. The effects of phosphorothioated ODNs containing human bcl-2 sense and bcl-2 antisense sequences that were transfected with Lipofectin on the proliferation and viability of cultures of established human RCC cell lines were determined by MTS assay. The expression of Bcl-2 protein in ACHN tumor cells following antisense bcl-2 (AS2) ODN treatment was evaluated by Western blot analysis, and the extent of apoptosis in these cells was determined by fluorescence-activated cell sorter (FACS) analysis. The antitumor activity in ACHN xenografts in nu/nu mice was monitored by measuring differences in tumor weight in treated and control mice. RESULTS: Expression of bcl-2 mRNA was detected in all five RCC lines. Treatment with antisense bcl-2 ODNs inhibited the growth of all tested RCC cells and decreased Bcl-2 protein expression in ACHN cells. The AS2 antisense ODN complementary to the coding region of bcl-2 mRNA showed a superior antiproliferative effect compared with AS1 ODN complementary to the translation initiation region. Inhibition by antisense bcl-2 ODNs of ACHN cells was dose dependent. The FACS analysis revealed that growth inhibition was associated with the induction of programmed cell death. In vivo, AS2 ODN antitumor activity was noted in locally injected groups. CONCLUSIONS: Treatment of human RCC with antisense ODNs targeted to bcl-2 inhibits growth and is associated with the induction of programmed cell death. These results suggest therapeutic use of antisense bcl2 in the treatment of RCC.

Selective recruitment of CCR6-expressing cells by increased production of MIP-3 alpha in rheumatoid arthritis.

Infiltration of various types of leucocytes has been shown to play a crucial role in the pathogenesis of rheumatoid arthritis (RA). Macrophage inflammatory protein-3 alpha (MIP-3 alpha) is a recently identified chemokine which is a selective chemoattractant for leucocytes such as memory T cells, naïve B cells and immature dendritic cells. In this study, we investigated the expression of MIP-3 alpha and its specific receptor CCR6 in the inflamed joints of patients with RA. Increased amounts of MIP-3 alpha were found by ELISA in synovial fluids (SF) of patients with RA. MIP-3 alpha was apparently detected in all synovial tissue specimens of RA patients (n = 6), but it could not be detected in that of osteoarthritis (OA) patients (n = 4). Expression of MIP-3 alpha was detected especially in the sublining layer, and infiltrating mononuclear cells in RA synovial tissue. Gene expression of MIP-3 alpha was also found in six out of 11 RA-synovial fluid cells by RT-PCR. Cultured synovial fibroblasts derived from either RA or OA patients were capable of producing MIP-3 alpha in response to IL-1 beta and TNFalpha in vitro. Furthermore, expression of CCR6 was found in infiltrating mononuclear cells in the cellular clusters and around the vessels of RA synovial tissue. These findings indicate that increased production of MIP-3 alpha may contribute to the selective recruitment of CCR6-expressing cells in RA.

Phasic mechanoreceptor stimuli can induce phasic activation of upper airway muscles in humans.

1. Upper airway dilator muscles are phasically activated throughout breathing by respiratory pattern generator neurons. Studies have shown that non-physiological upper airway mechanoreceptive stimuli (e.g. rapidly imposed pulses of negative pressure) also activate these muscles. Such reflexes may become activated during conditions that alter airway resistance in order to stabilise airway patency. 2. To determine the contribution of ongoing mechanoreceptive reflexes to phasic activity of airway dilators, we assessed genioglossal electromyogram (GG EMG: rectified with moving time average of 100 ms) during slow (physiological) oscillations in negative pressure generated spontaneously and passively (negative pressure ventilator). 3. Nineteen healthy adults were studied while awake, during passive mechanical ventilation across normal physiological ranges of breathing rates (13-19 breaths min-1) and volumes (0.5-1.0 l) and during spontaneous breathing across the physiological range of end-tidal carbon dioxide (PET,CO2; 32-45 mmHg). 4. Within-breath phasic changes in airway mechanoreceptor stimuli (negative pressure or flow) were highly correlated with within-breath phasic genioglossal activation, probably representing a robust mechanoreceptive reflex. These reflex relationships were largely unchanged by alterations in central drive to respiratory pump muscles or the rate of mechanical ventilation within the ranges studied. A multivariate model revealed that tonic GG EMG, PET,CO2 and breath duration provided no significant independent information in the prediction of inspiratory peak GG EMG beyond that provided by epiglottic pressure, which alone explained 93 % of the variation in peak GG EMG across all conditions. The overall relationship was: Peak GG EMG = 79.7 - (11.3 X Peak epiglottic pressure), where GG EMG is measured as percentage of baseline, and epiglottic pressure is in cmH2O. 5. These data provide strong evidence that upper airway dilator muscles can be activated throughout inspiration via ongoing mechanoreceptor reflexes. Such a feedback mechanism is likely to be active on a within-breath basis to protect upper airway patency in awake humans. This mechanism could mediate the increased genioglossal activity observed in patients with obstructive sleep apnoea (i.e. reflex compensation for an anatomically smaller airway).

Up-regulation of prostaglandin E receptor EP2 and EP4 subtypes in rat synovial tissues with adjuvant arthritis.

To evaluate the role of the prostaglandin E receptor (EP) subtypes in the development of inflammatory synovitis, we examined EP subtype mRNA distribution in the synovial tissue of rats with adjuvant arthritis and the effect of selective EP agonists on cytokine production by cultured rat synovial cells. We used reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization to measure the level of EP subtype (EP1, EP2, EP3, and EP4) mRNA expression in synovial tissues and cultured synovial cells from the arthritic joints of rats. RT-PCR and ELISA were used to analyse the effects of two selective EP agonists on IL-6 production by cultured rat synovial cells. EP2 and EP4 mRNA expression in inflamed synovial tissues was up-regulated. EP2 and EP4 mRNA were co-expressed in synovial macrophages and fibroblasts in inflamed tissues. EP4 and EP2 agonists both inhibited IL-1-induced IL-6 production. Our results suggest that prostaglandin E2 regulates the functions of synovial macrophages and fibroblasts through EP2 and EP4, which are induced by inflammatory stimuli in rats with adjuvant arthritis.

Hyperbilirubinemia induced by endoscopic variceal ligation for esophageal varices in a patient with primary biliary cirrhosis: a case report.

We describe the case of a 51-year-old woman with primary biliary cirrhosis who developed hyperbilirubinemia with transient liver dysfunction after undergoing endoscopic variceral ligation to control hemorrhaging from esophageal varices. After undergoing a variceal ligation, the serum total bilirubin increased from 4.0 mg/dL to 9.5 mg/dL, and the degree of liver failure worsened. She finally had to undergo a liver transplant. We discuss the mechanism of hyperbilirubinemia after endoscopic variceal ligation.

Activated Ras modifies the proliferative response of rheumatoid synovial cells to TNF-alpha and TGF-alpha.

OBJECTIVE: To study the role of the Ras/mitogen-activated protein kinase (MAPK) pathway in the proliferative response of rheumatoid synovial fibroblast (RSF) to tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-alpha. METHODS: V-Ki-ras gene was introduced into RSF using a retrovirus and the proliferative response of these cells to TNF-alpha or TGF-alpha was estimated by measuring the uptake of 3H-thymidine. The effect of a mitogen-activated protein kinase kinase (MEK) inhibitor, PD98059, was also investigated. RESULTS: Consistent with previous reports, TNF-alpha and TGF-alpha stimulated the proliferation of RSF. When the v-Ki-ras gene was expressed, the basal growth rate of these cells was increased, but their growth was suppressed by TNF-alpha or TGF-alpha. The latter effect was abolished when the cells were exposed to a relatively low concentration of PD98059. CONCLUSION: Ras modulates the proliferative response of RSF to TNF-alpha and TGF-alpha.

Crescentic glomerulonephritis with antimyeloperoxidase antibodies developing during the course of IgA nephropathy in a patient with rheumatoid arthritis.

Abstract Glomerulonephritis, such as membranous nephropathy, IgA nephropathy, and p-antineutrophil cytoplasmic autoantibody (ANCA)-related crescentic glomerulonephritis, has been shown to occur in rheumatoid arthritis (RA). However, the occurrence of two types of glomerulonephritis in a patient with RA is rarely observed. Here, we describe a patient with RA who developed crescentic glomerulonephritis with antimyeloperoxidase (MPO) antibodies during the course of IgA nephropathy. This case indicates that crescentic glomerulonephritis and IgA nephropathy may occur together in association with p-ANCA in RA.

Effect of auranofin, an antirheumatic drug, on neutrophil apoptosis.

OBJECTIVE: The effects of auranofin (AF) on apoptosis and on the biological functions of neutrophils were investigated. METHODS: Neutrophils were incubated with various concentrations of AF for different periods. Cell viability was determined by the MTS assay and apoptosis was evaluated by flow cytometric analysis of propidium iodide (PI)- staining of the nuclei and annexin-V staining of phosphatidylserine in the cell membrane. The effect of AF on the expression of adhesion molecules (CD62L and CD11b/CD18) and on the generation of O2- by neutrophils was also determined. RESULTS: At a low concentration (1 microM), AF significantly prolonged neutrophil survival by delaying spontaneous apoptosis. Neutrophils incubated with AF for 12 and 24 hours maintained the capacity to express adhesion molecules and generate O2-. In contrast, a higher AF concentration (5 microM) shortened neutrophil survival by the induction of cell necrosis. CONCLUSION: Although the biological significance of inhibitory effect of AF on neutrophil apoptosis remains unclear, it seems to be unlikely that AF exerts the anti-inflammatory effect in vivo by directly suppressing neutrophil functions. Since AF has a wide range of effects on leukocytes, its therapeutic benefit in rheumatoid arthritis may be mediated in a complex manner.

Portal-systemic encephalopathy due to a congenital extrahepatic portosystemic shunt: three cases and literature review.

Extrahepatic portal-systemic encephalopathy due to congenital extrahepatic portosystemic shunt has so far been rarely reported in the literature. We herein report 3 such cases without liver cirrhosis or portal hypertension which were presented with the chief complaint being disturbance of consciousness and abnormal behavior. In all cases the brain computed tomography scan revealed no pathological findings, while electroencephalogram showed a diffuse slow activity with triphasic waves. The laboratory data revealed a high serum ammonia level. Percutaneous transhepatic portography demonstrated portosystemic shunts. After these shunts were surgically occluded, the serum ammonia level reached a normal range and encephalopathy disappeared. A liver biopsy also revealed neither fibrosis nor cirrhosis in any of the cases. The 23 previously reported cases are also discussed.

Influence of chemoreceptor stimuli on genioglossal response to negative pressure in humans.

Genioglossal muscle (GG) activity is modulated by both chemoreceptive and mechanoreceptive reflexes that help stabilize airway patency. We assessed the effects of blood gas changes, within the range encountered during mild obstructive apnea-arousal cycles, on GG activity and the GG reflex to upper airway negative pressure. Eighteen healthy adults were studied while awake under 5 conditions: (1) baseline (PET(CO(2)) = 40 mm Hg, Sa(O(2)) = 99%); (2) hypercapnia (PET(CO(2)) = 45 mm Hg); (3) hypocapnia (PET(CO(2)) = 35 mm Hg, induced via hyperventilation with an iron lung ventilator); (4) hypoxia (Sa(O(2)) = 87%); and (5) hypercapnia plus hypoxia (PET(CO(2)) = 45 mm Hg, Sa(O(2)) = 87%). Measurements included airflow, choanal and epiglottic pressures (Pchoa and Pepi), upper airway resistance, phasic and tonic GG EMG, and the GG reflex to negative pressure (Pchoa = -12.5 cm H(2)O). Ventilation increased from a baseline of 10.7 up to 22.7 L. min(-1) under conditions of altered blood gases. Peak inspiratory phasic GG EMG increased from 6. 5 to 11.1% of maximal contraction but there were no significant changes in either tonic GG EMG (range, 4.3 to 5.8% of maximum) or magnitude of the GG reflex (range, 4.1 to 5.5% of maximum). Among conditions there was a high correlation between upper airway pressures and peak phasic GG EMG (Pchoa, r = 0.97, p < 0.01; Pepi, r = 0.87; p = 0.06). We conclude that in this range of blood gases: (1) the GG reflex to negative pressure is unchanged; (2) slow airway pressure changes throughout inspiration, generated either actively or passively, influence GG EMG activity; and (3) mechanoreceptive control of GG EMG can fully explain all changes in GG activity, suggesting that chemoreceptive inputs to GG are minimal, or are not simply summated with mechanoreceptor inputs.

Induction of neutrophil death resembling neither apoptosis nor necrosis by ONO-AE-248, a selective agonist for PGE2 receptor subtype 3.

An increase of intracellular cAMP mediated by prostaglandin E2 (PGE2) has been shown to delay spontaneous apoptosis of neutrophils. It has been demonstrated that a selective agonist for PGE2 receptor subtype 3 (the EP3 receptor) is capable of decreasing cAMP and stimulating phosphoinositide turnover in various types of cells. We investigated the effect of a selective EP3 receptor agonist, ONO-AE-248, on neutrophil viability. ONO-AE-248 rapidly caused a unique form of neutrophil death. The agonist primarily induced morphological changes of the nucleus, including fusion of the lobules, decreased compactness of the chromatin, and blebbing and rupture of the nuclear membrane. This was followed by an increase of plasma membrane permeability and cell lysis. During these processes, neither apoptotic changes such as nuclear condensation, DNA fragmentation, and expression of phospholipid phosphatidylserine on the plasma membrane nor necrotic changes such as chromatin clumping and organelle destruction were apparent in the treated neutrophils. The fatal effect of the agonist night be specific for neutrophils because it failed to promote the rapid death of other types of cells. Although activation of neutrophils by ONO-AE-248 was not evident, experiments using metabolic inhibitors demonstrated that the agonist caused neutrophil death via the activation of protein kinase C in the presence of intracellular ATP. These findings indicated that EP3 receptor-mediated signals might promote a novel form of neutrophil death, which differs from typical apoptosis or necrosis.