[Genotypes of cystic fibrosis (CF) reported in the world and polymorphisms of cystic fibrosis transmembrane conductance regulator (CFTR) gene in Japanese]

Cystic fibrosis (CF) is a common autosomal recessive genetic disorder in Caucasians. Since identification of the gene responsible for CF in 1989, over 400 sequential alterations of the CFTR gene have been tabulated by the CF Genetic Analysis Consortium. However, except for the delta F508 mutation, which occurs in approximately 70% of CF chromosomes, the worldwide frequency of most mutations in this gene is less than 1%. In Orientals and African blacks, CF is very rare. In Japanese only 100 cases have been reported. A few genotypes of these cases have been analyzed but no delta F508 or other mutations were found. We have analyzed mutations of the CFTR gene in Japanese with diffuse panbronchiolitis (DPB), which is found only in Orientals and shares pathologic and clinical characteristics with mild adult CF. However, no significant mutation of the CFTR gene was identified in this series. This suggests a different etiological background from that of CF.

Angiotensin converting enzyme (ACE) inhibitor-induced cough and substance P

BACKGROUND

Angiotensin converting enzyme (ACE) inhibitors cause coughing in 5-10% of patients, but the exact mechanisms of this effect are still unclear. In the airways ACE degrades substance P so the cough mechanism may be related to this peptide.

METHODS

Nine patients who developed a cough and five patients who did not develop a cough when taking the ACE inhibitor enalapril (2.5 or 5.0 mg/day) for hypertension were enrolled in the study. No subjects had respiratory disease and the respiratory function of all subjects was normal. One month after stopping enalapril, inhalation of hypertonic saline (4%) was performed using an ultrasonic nebuliser for 15-30 minutes to induce sputum. The concentration of substance P in the sputum sample was measured by radioimmunoassay. In four of the nine cases with a cough enalapril was given again for 1-2 weeks and the concentration of substance P in the induced sputum was again measured.

RESULTS

One month after stopping enalapril the mean (SE) concentration of substance P in the sputum of the group with a cough was 16.6 (3.0) fmol/ml, significantly higher than that in the subjects without a cough (0.9 (0.5) fmol/ml). All four subjects in the group with a cough who were given a repeat dose of enalapril developed a cough again, but the concentrations of substance P in the induced sputum while taking enalapril (17.9 (3.2) fmol/ml) were similar to the values whilst off enalapril (20.0 (2.5) fmol/ml).

CONCLUSIONS

The mechanisms of ACE inhibitor-induced coughing may involve substance P mediated airway priming. However, the final triggering of the ACE inhibitor-induced coughing is unlikely to be due to this peptide.

[A comparative study on the efficacies of ritipenem acoxil and cefotiam hexetil in bacterial pneumonia by the double-blind method]

To objectively evaluate the efficacy, safety and usefulness of the newly developed penem oral antibiotic, ritipenem acoxil (RIPM-AC), against bacterial pneumonia, we conducted a multi-center double-blind comparative study using cefotiam hexetil (CTM-HE) as the control drug. Both RIPM-AC and CTM-HE were orally administered at 200 mg t.i.d. for 14 days, in principle. The results were as follows: The total number of patients enrolled in this trial was 208, of which 152 cases (RIPM-AC group: 73, CTM-HE group: 79) were evaluable for clinical efficacy. 1. The clinical efficacy rates (excellent + good) were 91.8% (67/73) in the RIPM-AC group and 94.9% (75/79) in the CMT-HE group. There was no significant difference between the two groups, and the clinical equivalency of RIPM-AC to CTM-HE was demonstrated. 2. In the patients enrolled in the evaluation of clinical efficacy, the eradication rates of the causative organisms were 84.6% (22/26) in the RIPM-AC group and 91.7% (22/24) in the CTM-HE group, with no significant difference between the two groups. 3. Side effects were noted in 9 cases (9.6%) of the RIPM-AC group and 5 cases (4.9%) of the CTM-HE group. Abnormal laboratory test findings were observed in 23 cases (26.7%) of the RIPM-AC group and 15 cases (15.6%) of the CTM-HE group. There was no significant differences between the two groups in the incidence of side effects nor of abnormal laboratory test findings. In the safety evaluation, RIPM-AC was judged to be safe in 64 cases (68.1%) and CTM-HE in 82 cases (80.4%), with no significant difference. 4. The usefulness rates (markedly useful+useful) were 86.5% (64/74) in the RIPM-AC group and 92.5% (74/80) in the CTM-HE group. There was no significant difference between the two groups. Since RIPM-AC showed clinical efficacy similar to those of CTM-HE and posed no particular safety problems, it is expected to be a useful antibiotic for the treatment of bacterial pneumonia.

Morphologic aspects of airways of patients with pulmonary emphysema followed by bronchial asthma-like attack

Morphometric analysis of airways was performed in autopsied lungs from four patients with pulmonary emphysema (PE) followed by bronchial-asthma (BA)-like attacks (Group PE+BA) (four males, 72 +/- 9 yr). The results were compared with those from five pulmonary emphysema patients (Group PE) (five males, age 71 +/- 4 hr), three patients with bronchial asthma (Group BA) (one female and two males, age 65 +/- 7 yr), and four control subjects with no pulmonary diseases (Group Cont) (one female, three males, age 64 +/- 4 yr). The proportion of gland area to bronchial wall (gland%), ratio of goblet-cell occupancy to the total epithelial layer (goblet%), thickness of the basement membrane, amount of intraluminal mucus (mucus occupying ratio; MOR%), and number of various cell types per square millimeter in airway walls in a section 4 microns thick were measured in central (3 to 8 mm diameter) and peripheral airways (2 mm or less diameter). Gland% for the PE+BA group was significantly greater than that for the Cont group, whereas it did not differ significantly from that of the PE or BA groups. Goblet% and thickness of the basement membrane in central and/or peripheral airways in Group PE+BA were significantly greater than those in Group Cont, whereas those in Group PE were similar to those in Group Cont. Although not statistically significant, MOR% in central and peripheral airways from Group PE+BA showed a similar value to that in Group BA, whereas MOR% in Group PE was the same as that in Group Cont. The eosinophil number in peripheral airways walls in Group PE+BA showed a similar value to that in Group BA, which was significantly greater than in Group Cont. Other cells (macrophages, lymphocytes, and neutrophils) showed similar values among Groups PE+BA, PE, and BA. The number of eosinophils in central and/or peripheral airways correlated significantly with both goblet% and BMT, whereas other cells did not. These findings indicate that the airways of Group PE+BA are morphologically similar to those of Group BA, suggesting a combination of pulmonary emphysema with bronchial asthma.

Deterioration of urinary findings after tonsil stimulation in patients with IgA nephropathy

We studied whether urinary findings are affected by stimulation of tonsils in patients with IgA nephropathy. In 62 patients with IgA nephropathy and 20 patients with other renal diseases tonsils were stimulated by an ultra short wave for 10 min. Changes in amount of urinary protein, urinary sediment, blood leucocyte count, concentrations of serum IgA and serum secretory IgA were evaluated after tonsil stimulation. Forty of 62 patients with IgA nephropathy (65%) showed deterioration of urinary findings after the stimulation compared with 6 of 20 patients with other renal diseases (30%). The deterioration was significantly more frequent in IgA nephropathy than in other renal diseases (p <0.005). Previous episodes of gross hematuria following upper respiratory tract infections had occurred in 17 of 40 patients who showed deterioration of urinary findings after tonsil stimulation (43%) as against in 4 of 22 without deterioration (18%). The level of serum secretory IgA was higher in patients who showed deterioration of urinary findings after tonsil stimulation than in those who did not show it. Though tonsil stimulation increased blood leucocyte count it did not affect the concentrations of serum IgA or secretory IgA. It is concluded that tonsil stimulation often deteriorates urinary findings in patients with IgA nephropathy; therefore chronic tonsillitis may play a part in the pathogenesis of IgA nephropathy.

Theoretical treatment of striated muscle: Dynamic extension of four-state model

We constructed a muscle model, based on the model first proposed by Gray and Gonda [6,7), that simulates the twitch contraction of striated muscle. Their original model postulated four basic states in the contraction cycle and predicted the properties of steady state contraction in striated muscle. Using the relationship between steady state tension and calcium concentration, we described several rate constants as functions of calcium concentration and calculated the number of attached crossbridges at various calcium concentration values. The results for both skeletal and cardiac muscle were approximately consistent with those of X-ray studies. Assuming that rate constants change immediately with the phasic alteration of intracellular calcium concentration, we estimated the time course of crossbridge distribution during twitch contraction; these findings were also consistent with those of X-ray studies. We also simulated the effects of calcium concentration and sarcomere length on the magnitude of twitch tension. These simulations suggest that the major determinants of crossbridge distribution during twitch contraction are the time courses of calcium transients and the rate constants of crossbridge kinetics. Our findings suggest that the model used in this study provides a theoretical basis for interpreting the characteristics of cardiac muscle encountered in the clinical setting.

Coronary angioplasty ameliorates hypoperfusion-induced endothelial dysfunction in patients with stable angina pectoris

OBJECTIVES

This study sought to investigate the effect of coronary angioplasty on chronic hypoperfusion-induced endothelial dysfunction in patients with coronary heart disease.

BACKGROUND

The endothelium is an important component for organ flow regulation. Ischemia with or without reperfusion is known to cause endothelial dysfunction. We tested the hypothesis that chronic hypoperfusion impairs endothelial function in the angiographically normal coronary artery segment distal to stenosis and that the impairment by chronic hypoperfusion is reduced by coronary angioplasty.

METHODS

In 13 patients with stable angina pectoris, substance P (10, 30 and 100 pmol) and nitroglycerin (200 micrograms) were sequentially infused into the coronary artery in a cumulative manner on the day after coronary angioplasty. In 10 of these patients, vascular responses to these agents were again investigated 3 months after angioplasty. Changes in vascular diameter were evaluated in vessels located proximal and distal to the target lesion, both of which were angiographically normal, by performing computer-assisted quantitative coronary angiography. In five patients, the transstenotic pressure gradient was also measured with a pressure sensor-mounted guide wire before angioplasty.

RESULTS

On the day after angioplasty, the magnitude of dilation by substance P in distal segments was significantly less than that in proximal segments and inversely correlated with the transstenotic pressure gradient (p < 0.05) and lesion stenosis (p < 0.05). There was no difference in nitroglycerin-induced vasodilation between the two vessel segment groups. Three months later, the impaired response to substance P in the distal segment was restored to normal.

CONCLUSIONS

We conclude that chronic hypoperfusion impairs endothelium-dependent dilation of coronary artery distal to critical stenosis in patients with ischemic heart disease and that coronary angioplasty ameliorates the endothelial dysfunction within 3 months.

Nitrogen dioxide exposure increases airway contractile response to histamine by decreasing histamine N-methyltransferase activity in guinea pigs

To determine the mechanism responsible for nitrogen dioxide (NO2)-induced airway hyperresponsiveness, we examined the effects of NO2 exposure on the contractile response to histamine and the level of histamine N-methyltransferase (HMT) activity, a histamine-degrading enzyme, in guinea pig trachea in vitro. Guinea pigs were divided into seven groups. Each group received continuous NO2 exposure (2.0 ppm) for either 2, 6, 12, 24, 48, or 96 h. The remaining group did not receive NO2 exposure (control). HMT activity in trachea was decreased from the control value of 70.3 +/- 7.7 pmol/min/mg protein to 34.6 +/- 6.7 pmol/min/mg protein by 12 h exposures of NO2. However, 24 and 48 h exposures of NO2 did not significantly alter HMT activity. In contrast, HMT activity exceeded the control value by 96 h exposures of NO2 (85.5 +/- 5.1 pmol/min/mg protein). Twelve hour exposures of NO2 shifted the concentration-response curves to histamine to lower concentrations and significantly reduced the median effective concentration (EC50) of histamine (log M) from the control value of -5.16 +/- 0.09 to -6.15 +/- 0.14 (P < 0.01). In contrast, the EC50 concentration of histamine (log M) increased from the control value of -5.20 +/- 0.10 to -4.90 +/- 0.11 by 96 h exposures of NO2 (P < 0.05). However, NO2 exposure did not alter the contractile response to acetylcholine. Morphologically, tracheal epithelial cells had vacuoles after 12 h exposures of NO2, but denudation of the epithelium did not occur during this experiment. In situ hybridization for HMT mRNA demonstrated that the level of HMT mRNA increased dominantly in tracheal epithelial cells after 96 h exposures of NO2. The present results indicated that the decrease in the level of HMT activity in the trachea was closely associated with the increase in the airway contractile response to histamine, suggesting that NO2-induced transient airway hyperresponsiveness to histamine is due to the decreased capacity of histamine catabolism in airway.

Eosinophil adhesion to cultured airway epithelial cells from guinea pig lungs

We examined the effects of histamine, tumor necrosis factor-alpha (TNF alpha), interferon-gamma (IFN gamma), indomethacin and dexamethasone on the adherence of eosinophils to airway epithelial cells. Epithelial cells were isolated from guinea pig trachea through enzymatic digestion, and cultured until they showed confluence. Eosinophils were taken by peritoneal lavage from guinea pigs sensitized with horse serum and purified. The adhesion of eosinophils to cultured epithelial cells was examined using 51Cr. The percentage adhesion was obtained by dividing counts per minute of lysed eosinophils adhered to epithelial cells by suspended eosinophils. Histamine significantly increased the adhesion of eosinophils to epithelial cells, while TNF alpha or IFN gamma did not significantly alter the adhesion. Indomethacin significantly inhibited the adhesion of eosinophils to epithelial cells in both nontreated and histamine-induced conditions. Dexamethasone also reduced adhesion, although it did not reach statistical significance. These findings indicate that histamine induced eosinophil adherence to airway epithelial cells, suggesting a role of endogenous prostaglandins in adherence.

Tissue Factor Pathway Inhibitor Production by Human Mesangial Cells in Culture

Fibrin formation within the glomeruli has been observed in various forms of human and experimental glomerulonephritis and it may play an important role in progressive glomerular injury. Furthermore it has been hypothesized that glomerular fibrin deposition may occur through activation of either the intrinsic or extrinsic coagulation pathway. It has been demonstrated that a procoagulant activity (PCA) which is compatible with tissue factor is present in the glomeruli and becomes increased in human proliferative glomerulonephritis and in animal models of nephritis. Tissue factor pathway inhibitor (TFPI) regulates the extrinsic pathway of blood coagulation through its ability to inhibit tissue factor activity. TFPI is present in plasma and in platelets, and it is now thought to be produced mainly by endothelial cells. We examined whether human mesangial cells (HMC) could produce TFPI and attempted to clarify regulatory factors which affect TFPI production. Cultured HMC were used and TFPI in the cell supernatants was measured by ELISA using a specific antibody. Cultured HMC showed the production of TFPI. Immunoblot analysis revealed 40 kD protein of TFPI. The concentration of TFPI was significantly increased following the incubation with thrombin and heparin, including low molecular weight heparin, in a dose- and time-dependent manner. However, fetal calf serum, phorbol myristate acetate, lipopolysaccharide, IL-1β and tissue factor did not stimulate TFPI synthesis. Our data show that cultured HMC have the ability to produce TFPI which inhibits fibrin formation. It is possible that thrombin-induced enhancement of TFPI synthesis may be caused by the autoregulatory system of blood coagulation and that with heparin it may represent another anticoagulatory effect of heparin.

Role of the parabrachial nucleus in ventilatory responses of awake rats

1. The parabrachial nucleus (PBN) is thought to play an important role in cardiorespiratory control. However, the circumstances under which it affects ventilation are still not known. The purpose of the present study was to investigate how the PBN modulates the ventilatory responses to hypercapnia, hypoxia or a resistive load in awake rats with chemical lesions of the PBN. 2. In three groups of rats (with lateral PBN lesion, with Kölliker-Fuse nucleus lesion and control), ventilation was measured under various conditions. 3. There was no difference in the breathing of normal room air in any of the groups. However, the lesioned groups showed a reduced ventilatory response to hyperoxic hypercapnia (inspired CO2 fractions (FI,CO2) of 3, 5, 8 and 10%) and to graded hypoxia (inspired O2 fractions (FI,O2) of 16, 12, 10 and 8%) compared with the control group. The control group showed a biphasic response to sustained hypoxia (FI,O2 at 10% for 30 min), known as 'hypoxic depression', while the lesioned groups showed moderate ventilatory exaggeration throughout hypoxia. In response to a resistive load, the lateral PBN lesion group showed no change in ventilatory compensation. 4. The PBN appeared to have a considerable influence on ventilation stimulated in various ways during wakefulness.

[Portable home monitoring system in screening for sleep-disordered breathing]

Screening for sleep-disordered breathing is often done in an interview and with a questionnaire. This method is indirect and it appears to underestimate the prevalence of sleep apnea syndrome. Recently, several devices such as the Medilog and Vitalog portable monitoring systems were developed. However, these devices are difficult for patients to operate by themselves, because they include EEG monitoring or measurement of chest and abdominal movement. Therefore, we developed a portable monitoring system that is easier to operate. This system can be used to assess three variables: oronasal airflow, tracheal sound, and electrical activity of the heart. It stores the time of the onset of apnea, apnea duration, and R-R intervals with a built-in microcomputer. Apnea episodes, total apnea time, mean apnea time, and R-R interval are analyzed with a host computer. The sensitivity an specificity of this system are 92.5% and 87.5%, respectively, with an apnea index (AI) of less than 10 episodes/h. Using this device, we found that the prevalence of sleep apnea syndrome among Japanese industrial workers who had an AI of more than 10 episodes was 7.5%. Moreover, from 1984 to 1994 we used this device to monitor 1019 outpatients who complained of sleep disturbances such as snoring, abnormal breathing during sleep, and excessive daytime sleepiness, and found sleep apnea (AI > or = 10) in about 50% of these patients. This monitoring system is useful for screening of outpatients with sleep apnea and for epidemiological studies of sleep apnea. However, it may be necessary to include a non-invasive system for monitoring oxygen saturation in the portable sleep monitor, to detect hypoventilation during sleep.

Allergic airway response and potassium channels: histamine release and airway inflammation

The possible involvement of potassium (K) channels in allergic airway responses was examined in ovalbumin (OA)-sensitized guinea pigs. An ATP-sensitive K channel opener (BRL-38227) inhibited OA inhalation-induced bronchoconstriction and airway plasma leakage. BRL-38227 also had an inhibitory effect on exogenous histamine- and leukotriene-induced responses. In contrast, BRL-38227 did not affect OA-induced histamine release from minced lung tissues. Therefore, the ATP-sensitive K channel opener inhibits allergic bronchoconstriction and plasma leakage as a result of its effect on airway smooth muscle and postcapillary venules. Apamin, a small conductance Ca2+ -activated K channel (PK,Ca) blocker, significantly inhibited both OA-induced tracheal contraction and histamine release from lung tissues, suggesting that this compound reduces allergic airway responses via a mast cell stabilizing effect. We conclude that ATP-sensitive K channel opening and small conductance PK,Ca closure may be beneficial for preventing allergic airway responses.

TNF-alpha mRNA expression in diaphragm muscle after endotoxin administration

We studied gene expression and production of TNF-alpha in the diaphragm tissue and changes of muscle contractile properties after endotoxin injection (Escherichia coli, 20 mg/kg) in 88 rats. We assessed the muscle contractile properties by force-frequency curves and twitch kinetics using dissected diaphragm muscle strips. The peak tensions of force-frequency curves decreased from control values (2.15 +/- 0.2 kg/cm2) up to 4 h (0.81 +/- 0.17, p < 0.001), and then increased at 6 h (1.36 +/- 0.19, p < 0.05) after endotoxin injection. The cytotoxic activity on L929 cells in arterial blood samples maximally increased at 2 h (p < 0.001), then decreased to 6 h (p < 0.05). TNF-alpha mRNA in diaphragm tissue was detected by Northern blot method at 1 and 1.5 h, and the immunolocalization of TNF-alpha was evaluated at 2 and 4 h by immunohistochemistry in the muscle tissues. Furthermore, preinjection with anti-m TNF-alpha antibody prevented the decrement of force-frequency curves after endotoxin injection of 10 microliters/kg. From this evidence that TNF-alpha gene expression and production occurred in the diaphragm tissue, but anti-m TNF-alpha antibody preinjection prevented the deterioration of diaphragm muscle contractile properties, we suggest that TNF-alpha may act on muscle cells extracellularly.

Significance of the right ventricular free wall in dogs with and without pulmonary constriction

To evaluate the role of the right ventricular (RV) free wall in cardiac function, RV and left ventricular (LV) wall segment lengths were measured by ultrasonic crystals in 10 open chest dogs with the pericardium preserved. Right coronary artery (RCA) was perfused separately by own blood and the flow was reduced stepwise until active shortening (delta L) of the RV segment disappeared or RCA flow became zero (Ischemia). The experiment was repeated with and without pulmonary stenosis (PS). At Ischemia, RV and LV systolic pressures decreased. RV end-diastolic length increased and RV delta L decreased. LV end-diastolic length and LV delta L were reduced. LV stroke volume concurrently fell. These changes became more prominent with PS. The critical level of RCA flow, at which RV delta L began to change, was higher with PS (5.27 +/- 2.85 ml/min, mean +/- S.D.) than without PS (1.44 +/- 1.16, p < 0.01). Based on the relationships between RV delta L and percent changes in RV developed pressure and stroke volume, the degree of the decreases in RV developed pressure and stroke volume at RV delta L of zero were estimated to be about 20%. These results indicate that the RV free wall partly contributes to maintaining the RV function, especially during RV pressure overload.

Nitric oxide regulation of glycoconjugate secretion from feline and human airways in vitro

To determine whether nitric oxide (NO) regulates mucus secretion from airway submucosal glands which are the main source of human airway secretion, we examined the effects of NO synthase inhibitors (L-NAME and L-NMMA) on mucus glycoprotein (MGP) secretion from feline and human airway explants (with epithelium) and isolated submucosal glands. MGP secretion was estimated by measuring trichloroacetic-acid (TCA) precipitable [H3]-glycoconjugates using secretory indices. NO synthase inhibitors alone did not alter significantly MGP secretion from explants or isolated glands. Pretreatment with NO synthase inhibitors significantly inhibited both methacholine (MCh) and bradykinin (BK)-induced secretion from isolated glands, but not significantly inhibit the secretion from explants. The inhibition by L-NAME was reversed by the addition of L-arginine in both MCh- and BK-induced secretions from isolated glands. Further, a NO generator isosorbide dinitrate induced a significant increase in the secretion. These findings suggest that endogenous NO has a stimulatory action in airway submucosal gland secretion and directly regulates the secretion from submucosal glands independently of superficial epithelial cells.

Increased regional systolic myocardial stiffness of the left ventricle during coronary artery occlusion in a dog: analysis of the finite element model

(1) We measured the instantaneous systolic transfer function of an isolated canine left ventricle (LV) before and after the ligation of the left anterior descending coronary artery (LAD). The instantaneous transfer function before the ligation of the LAD showed a resonance curve whose peak frequency was 30 to 70 Hz. On the other hand, the transfer function 40 min after the ligation of the LAD showed a divided peak in the resonance curve. (2) We constructed a finite element model of a thick-walled spherical shell with a non-uniform structure. In this model, the myocardial elasticity and viscosity of the ischemic region are different from those of non-ischemic regions. One can calculate the theoretical transfer function using modal analysis and also estimate the elasticity and the viscous coefficient of both non-ischemic and ischemic myocardium by fitting the theoretical transfer function to the experimental one. (3) The estimated elasticity of the ischemic myocardium was three to five times larger than that of the non-ischemic myocardium. The estimated viscous coefficient of the ischemic myocardium was about half that of the non-ischemic myocardium. These results showed that ischemia alters the viscoelastic properties of the myocardium during systole as well as during diastole.

Vasodilatory effect of nicorandil on coronary arterial microvessels: its dependency on vessel size and the involvement of the ATP-sensitive potassium channels

We aimed to clarify the size dependency of nicorandil-induced dilation in coronary microcirculation and the involvement of adenosine triphosphate (ATP)-sensitive potassium channels. Coronary arterial microvessels were observed through a microscope equipped with a floating objective in anesthetized open-chest dogs (n = 29). Heart rate and mean aortic pressure were maintained at control level. In 16 dogs, nicorandil was infused into the coronary in a cumulative fashion (0.1, 1.0, 10, and 100 micrograms/kg/min, for 5 min for each dose). In 13 dogs, glibenclamide (10 microM) was topically applied onto the observed area, and nicorandil was similarly infused. Nicorandil dilated vessels < 100 microns in diameter at all applied doses in a dose-dependent manner. Glibenclamide abolished the dilation of these vessels at the lower two doses. Vessels > 100 microns in diameter dilated only at the two higher doses and the dilation was not affected by glibenclamide. These data suggest that the vessels < 100 microns are more sensitive to this agent than other size vessels, and that ATP-sensitive potassium channels are involved in the nicorandil-induced dilation of vessels smaller than 100 microns, whereas the dilation of other size vessels occurs independently of this channel.

IL-5, IL-8 and GM-CSF immunostaining of sputum cells in bronchial asthma and chronic bronchitis

BACKGROUND

Granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin (IL)-5 or IL-8 have been suggested to play an important role in the pathogenesis of eosinophilic airway inflammation in bronchial asthma or neutrophilic airway inflammation in chronic bronchitis, respectively, However, GM-CSF and IL-8 have biological activities to either eosinophils or neutrophils.

OBJECTIVE

To investigate the contribution of these cytokines to airway inflammation, we compared the cellular differential and immunolocalization of GM-CSF, IL-5 and IL-8 in sputum cells from patients with bronchial asthma and chronic bronchitis.

METHODS

Cytospins of sputum cells from 12 patients with bronchial asthma and 12 with chronic bronchitis were subjected to cellular differential counting and immuno-cytochemistry with anti-human GM-CSF, IL-5 and IL-8 antibody.

RESULTS

The predominant cells in bronchial asthma were eosinophils and lymphocytes, while those in chronic bronchitis were neutrophils. All cytokines examined were detected in either bronchial asthma or chronic bronchitis, although the percentage of GM-CSF and Il-5 positive cells in bronchial asthma (53.4 +/- 6.0 [mean +/- SEM]% and 9.7 +/- 2.8%, respectively) was significantly higher than that in chronic bronchitis (11.4 +/- 2.5%; P < 0.001 and 1.7 +/- 0.3%; P < 0.007, respectively). In contrast, the percentage of IL-8 positive cells in chronic bronchitis (23.8 +/- 7.0%) was significantly higher than that in bronchial asthma (7.& +/- 1.9%; P < 0.04). The cells positive for IL-5 were lymphocytes in bronchial asthma and chronic bronchitis. The cells positive for GM-CSF in bronchial asthma were predominantly eosinophils, while those in chronic bronchitis were monocytes/macrophages and neutrophils. In contrast, neutrophils are mainly positive for IL-8 in chronic bronchitis, while monocytes/macrophages and bronchial epithelial cells are positive for IL-8 in bronchial asthma.

CONCLUSION

The immunochemical comparison of GM-CSF and IL-8 localization in sputum cells between bronchial asthma/chronic bronchitis suggests the differential regulation and roles of these cytokines in eosinophilic vs neutrophilic airway inflammation, resulting in the development of different types of airway inflammation.

Nitric oxide as a retrograde messenger in the nucleus tractus solitarii of rats during hypoxia

1. We examined the role of nitric oxide (NO) in respiratory regulation in the nucleus tractus solitarii (NTS), where L-glutamate release associated with peripheral chemoreceptor activation modulates the hypoxic ventilatory response. 2. Experiments were performed in unanaesthetized freely moving rats. First, the effects on the hypoxic ventilatory response of sodium nitroprusside (SNP, a NO donor) or NG-monomethyl-L-arginine (L-NMMA, a NO synthase inhibitor), microinjected into the NTS, were investigated. Second, using in vivo microdialysis, changes in extracellular L-glutamate during hypoxia were examined in the presence of L-NMMA. Third, the effect of L-NMMA on ventilatory augmentation by exogenous L-glutamate was examined. Furthermore, we measured extracellular L-citrulline concentration changes during hypoxia in the NTS to assess NO formation indirectly and also examined the effect of MK-801 (an NMDA receptor antagonist) on L-citrulline levels during hypoxia. 3. SNP increased ventilation during both normoxia and hypoxia. L-NMMA did not alter ventilation or L-glutamate levels during normoxia but significantly attenuated the hypoxic ventilatory response and the increase in L-glutamate during hypoxia. The inhibition by L-NMMA was blocked by L-arginine. The ventilatory augmentation by exogenous L-glutamate was attenuated by L-NMMA. L-Citrulline increased during hypoxia, and this increase was inhibited by MK-801. 4. We provide the first in vivo evidence that, in the NTS, NO works as a retrograde messenger in an L-glutamate-releasing positive feedback system contributing to the augmentation of ventilation during hypoxia.

Submental stimulation and supraglottic resistance during mouth breathing

We studied submental stimulation on supraglottic resistance (Rsg) in 5 normals and 6 patients with obstructive sleep apnea. We then examined the most effective sites of stimulation in the submental regions, and the relationships between Rsg and stimulation frequency and voltage in the supine position. Inspiratory and expiratory Rsg's were obtained as the slope of the linear portion of the pressure-flow relation determined at zero flow. Before stimulation, inspiratory and expiratory Rsg's were 0.76 +/- 0.06 (means +/- SE) and 0.61 +/- 0.02 cmH2O.L-1.sec, respectively, in normals, and 1.04 +/- 0.20 and 0.92 +/- 0.29 cmH2O.L-1.sec, respectively, in patients. Stimulation in the proximal half submental region with surface electrodes 1 cm apart decreased inspiratory and expiratory Rsg's in patients, and inspiratory Rsg in normals. Inspiratory Rsg measured in this submental region showed a stimulation frequency-and voltage-dependency in both groups, but expiratory Rsg did not. These findings suggest that submental stimulation in the proximal half region widens the supraglottic airway during mouth breathing and probably involves the upper airway muscles.

Eosinophil penetration through cultured human airway epithelial cell layer

We investigated the mechanisms of eosinophil penetration and mannitol permeability through a multilayer of cultured human tracheal epithelial cells. Wells of tissue culture plates were separated into the upper and the lower chambers by the cultured epithelial cell layer. 51Cr-labeled eosinophils or 3H-mannitol were put into the lower chamber. To stimulate the epithelial cells, platelet-activating factor (PAF) and/or phorbol myristate acetate (PMA) were added to the upper chamber. After 4 h of incubation, the eosinophil penetration rate was determined as a percentage of the total count added to the lower chamber. PMA significantly increased the eosinophil penetration rate in a dose-dependent manner (4.0% at 10(-5) M), compared with control (0.67%), whereas PAF itself did not. Activation of eosinophils by the addition of PAF to the lower chamber produced a significant increase in the eosinophil penetration (6.5% at 10(-6) M), which was inhibited by staurosporine. For determining the mannitol permeability, PMA, PAF, and/or supernatant from eosinophils were added to both upper and lower chambers and incubated for 30 min. PMA induced a significant increase in the mannitol permeability (175% of controls at 10(-5) M), whereas PAF itself did not alter it. Supernatant from eosinophils activated by PAF (10(-6) M) significantly increased the permeability (451% of controls), which was blocked by staurosporine. Supernatants from AA861 (a 5-lipoxygenase inhibitor)-treated or phenidon (a phospholipase A2 inhibitor)-treated eosinophils activated by PAF failed to alter the supernatant-induced increases in mannitol permeability.(ABSTRACT TRUNCATED AT 250 WORDS)