Risk of cytomegalovirus infection after peripheral blood stem cell transplantation

From 1992 to 1995, 105 patients received PBSCT in our hospitals and we observed no incidence of CMV-pneumonia. To clarify whether activation of CMV occurs in these patients shell vial cultures, CMV antigenemia and PCR (DNA-PCR and RT-PCR) were used as detection methods for CMV. Bronchoalveolar lavage (BAL) samples, MNC and PMN samples from peripheral blood leukocytes, and urine samples were taken from 17 patients on day 35 after PBSCT. CMV was detected in one urine specimen but not detected in any of the BAL, MNC or PMN specimens by shell vial culture. CMV antigenemia provided no positive data. Nine of the 74 samples taken from the 17 patients proved positive by DNA-PCR, but all CMV-mRNA results were negative by RT-PCR. We performed CMV antigenemia and PCR on MNC and PMN specimens from six patients every 1 to 2 weeks after transplantation to determine whether and when CMV was activated. Two patients tested positive transiently by DNA-PCR but negative throughout by both antigenemia and RT-PCR. These results suggest that the risk of CMV infection is low because the incidence of CMV activation in patients receiving PBSCT is low.

Portal hypertension in children and young adults: sonographic and color Doppler findings

Portal hypertension is a relatively uncommon pathologic condition in children and young adults in contrast with older adults. The aim of this study is to evaluate the utility of sonography and color Doppler sonography in the diagnosis of portal hypertension in children and young patients and to evaluate the sonographic pattern of each disease. We reviewed 25 such patients who were younger than 30 years old and obtained the following sonographic findings: (1) liver cirrhosis: (a) multiple intrahepatic venovenous shunts in patients with primary Budd-Chiari syndrome and (b) intrahepatic vascular narrowing and nodular coarse parenchymal texture, with multiple very-high-echo spots along the portal vein in patients with Wilson disease; (2) congenital hepatic fibrosis: marked and developed collaterals, wide periportal echogenic band, and a heterogeneous parenchymal texture comprised of multiple high echoes but without portal thrombus; and (3) extrahepatic portal thrombosis: invisible portal lumen except as an echogenic band. Sonography and color Doppler sonography are very useful in diagnosing these portal hypertensive diseases. However, there are no specific sonographic findings, and the role of sonography is limited to follow-up observation of associated secondary hepatobiliary changes in patients with congenital biliary atresia.

Lipopolysaccharide-induced goblet cell hypersecretion in the guinea pig trachea: inhibition by macrolides

We studied the effects of macrolides on lipopolysaccharide (LPS)-induced airway goblet cell secretion in the guinea pig trachea. The goblet cell secretion was assessed in histological sections of the tracheal mucosa stained with alcian blue and periodic acid Schiff by arbitrarily determining mucus score, which is inversely related to the magnitude of mucus discharge. Inhalation of Escherichia coli LPS (5 mg/kg) caused a time-dependent decrease in mucus score, with the maximal response being from 542 +/- 49 to 92 +/- 20 arbitrary units (P < 0.001) after 3 h, which was accompanied by an increase in the number of neutrophils in the tracheal mucosa. The LPS-induced mucus discharge was inhibited by oral clarithromycin and erythromycin in a dose-dependent manner (5 and 10 mg/kg), whereas amoxicillin and cefaclor had no effect. Each dose of clarithromycin and erythromycin, but not amoxicillin or cefaclor, likewise attenuated the LPS-induced recruitment of neutrophils. These results suggest that LPS stimulates goblet cell secretion and neutrophil accumulation in the airways and that macrolides may be of value in protecting against neutrophil-associated airway hypersecretion.

Large extrahepatic portosystemic shunt without portal hypertension

Extrahepatic portosystemic shunt usually occurs secondary to severe portal hypertension, and it is rare to encounter it in patients without portal hypertension. We report herein a large extrahepatic portosystemic shunt between the left gastric vein and left renal vein without portal hypertension in which color Doppler sonography was useful not only for detection but evaluation of the effect of embolization.

Increased oxidative metabolism in cow tracheal epithelial cells cultured at air-liquid interface

Airway epithelial cells cultured at the air-liquid interface possess highly differentiated functions and structures compared with the cells cultured under immersion. We examined the oxidative metabolism and glycolysis in cow tracheal epithelial cells on Days 3, 6, 10, and 13, cultured under three different conditions: (1) immersion culture on porous filters with apical and basolateral feeding (IM), (2) air-exposed culture on porous filters with basolateral feeding, i.e., air-liquid interface culture (AI), and (3) conventional immersion culture in plastic dishes with apical feeding (DI). Lactate production was less in AI than in IM and DI on Day 3 through Day 13, whereas cellular adenosine triphosphate content and basal O2 consumption were greater. Ouabain-sensitive and ouabain-insensitive O2 consumption, and the uncoupled O2 consumption were also greater in AI. Cytosolic lactate dehydrogenase activities on Day 10 were lower in AI, whereas alpha-ketoglutarate dehydrogenase activities were higher. The increased oxidative metabolism in AI was more pronounced at the late phase of culture (Days 10 and 13). In contrast, glycolysis remained elevated during the experiment in IM and DI. These data suggest that (I) AI begins to promote oxidative metabolism from growth phase by the provision of adequate oxygenation, and then further shifts to oxidative metabolism with differentiation; and (2) apical feeding may be responsible for the disturbance of the development of the oxidative metabolism.

Invasive thymoma with CD4+CD8+ double-positive T cell lymphocytosis

Lymphocytosis in the peripheral blood is a very rare manifestation of thymoma. A 45-year-old man presented with a giant mediastinal mass involving pleural dissemination and peripheral T cell lymphocytosis. Biopsy of the mediastinal mass revealed invasive thymoma, and two-color analysis of peripheral lymphocytes showed a marked increase in CD4+CD8+ double-positive cells. Both thymoma and lymphocytosis were improved by a combination of chemotherapy and mediastinal irradiation.

[Six patients with pneumonitis related to blended Chinese traditional medicines]

We encountered six patients with pneumonitis related to blended chinese traditional medicine (Kampo). The duration of treatment with kampo ranged from 14 to 110 days (mean: 38 days). The most common complaints were dyspnea, fever, and dry coughing. Fine crackles were heard at the bases of both lungs. Abnormal laboratory findings included high values of C-reactive protein and glutamic-oxaloacetic transaminase in all patients, lactate dehydrogenase in 5 patients, and eosinophil count in 1 patient. Chest X-ray films and CT films revealed diffuse reticulo-nodular interstitial shadows with consolidation in both lung fields in 3 patients and pleural effusion in 1 patient. Bronchoalveolar lavage was done in 4 patients; examination of the lavage fluid showed lymphocyte alveolitis, either pure or associated with neutrophilia and eosinophilia in 3 patients. Inverted CD4/CD8 lymphocyte ratios were found in 3 patients. Transbronchial lung biopsy was done in 4 patients and specimens from 3 of those 4 showed organizing pneumonitis with thickening of alveolar septa. Lymphocyte stimulation tests were positive in 4 patients. Discontinuation of the drug (2 patients) or administration of corticosteroids (4 patients) was followed by rapid improvement. Patients being treated with kampo preparations should be observed for signs and symptoms of drug-induced pneumonitis.

Effects of K(+)-channel blockers on epithelium-derived relaxing factor (EpDRF)-mediated modulation of airway smooth muscle contractility

Airway epithelium plays a role in the regulation of bronchial smooth muscle tone releasing cyclooxygenase products and epithelium-derived relaxing factor (EpDRF). To test possible involvement of K+ channels in the action of EpDRF, we studied rabbit tracheal segments in the presence of indomethacin under isometric conditions in vitro. Mechanical removal of the epithelium increased the contractile responses to acetylcholine, so that negative logarithm of the concentration required to produce 50% of maximal effect (pD2) increased from 5.0 +/- 0.4 to 5.7 +/- 0.3 (P < 0.01). Addition of charybdotoxin per se caused a leftward shift of acetylcholine concentration-response curves in epithelium-intact tissues, but the subsequent removal of the epithelium did not further potentiated the contractile responses. In contrast, apamin or glibenclamide had no effect on the epithelium-removal-induced potentiation of the contraction. The responses to electrical field stimulation were likewise potentiated by epithelial removal, an effect that was abolished by charybdotoxin. These results suggest that Ca(2+)-activated K+ channels are involved in the EpDRF modulation of airway smooth muscle responsiveness.

[Effect of sodium cromoglycate on airway vascular leakage caused by hypertonic saline in the rat trachea]

The action of the anti-asthmatic drug sodium cromoglycate (SCG) on airway inflammation remains uncertain. Using Evans blue dye as a maker of plasma leakage, we studied the effect of SCG on neurogenic vascular extravasation evoked by hypertonic saline (HTS) in the rat trachea. Inhalation of HTS (5-15%) caused a concentration-dependent increase in plasma leakage, but inhaled 0.9% NaCl had no effect. Inhalation of SCG did not affect the baseline level of vascular permeability, but it inhibited the effect of HTS in a dose-dependent manner: plasma extravasation induced by 10% NaCl was significantly reduced by 2 minutes of inhalation of SCG at concentrations of 10 and 50 mg/ml (p < 0.05 and p < 0.01, respectively). SCG (10 mg/ml), also inhibited the changes in microvascular permeability caused by aerosols of substance P (10(-4) M), whereas it did not affect the responses to aerosols of platelet-activating factor (3 x 10(-4) M). A similar dose of SCG did not significantly alter microvascular leakage caused by 5% NaCl. However, phosphoramidon, a selective inhibitor of neutral endopeptidase, potentiated the response to 5% NaCl, an effect that was inhibited by SCG (p < 0.05). These results suggest that SCG inhibits HTS-induced airway vascular permeability, presumably through a tachykinin-antagonist-like property, and that this inhibition is exaggerated when the activity of endogenous neutral endopeptidase is low.

Establishment of an in vitro assay system for screening hepatitis C virus protease inhibitors using high performance liquid chromatography

The hepatitis C virus (HCV) genome contains the code for a conserved, serine-type protease, called NS3, for the processing of the non-structural protein region of the viral polyproteins. Furthermore, a related protein, NS4A, is an effector or cofactor of NS3 protease activity in the cleavage of NS3-4A, NS4A-4B, NS4B-5A and NS5A-5B junctions. To establish an in vitro assay system for the screening of those enzyme inhibitors that inhibit the protease NS3-4A, we prepared a maltose-binding protein-NS3-NS4A fusion protein and a synthetic peptide substrate that mimics the NS5A-5B junction. Cleavage of the synthetic peptide was analyzed by reversed-phase high performance liquid chromatography (HPLC). We showed that the enzymatic activity of the NS3-NS4A fusion protein was enhanced in comparison to the NS3 protein alone. The assay conditions for optimum NS3-4A protease activity were determined to be pH 7.6 and 37 degrees C. In addition, we evaluated several protease inhibitors using the same HPLC assay system. The activity of HCV protease NS3-4A was inhibited by 2714.4 microM diisopropyl fluorophosphate, 270.8 microM N-tosyl-L-lysyl chloromethyl ketone, and 825.5 microM chymostatin. The results of the present study indicated that the synthetic peptide substrate and HPLC assay system are suitable for studying HCV protease activity and may facilitate the development of anti-HCV therapeutic reagents.

Cholinergic control of rabbit tracheal transepithelial potential difference in vivo

The aim of the present study was to investigate the role of the autonomic nervous system in the regulation of airway epithelial ion transport in vivo. Rabbits were anaesthetized and mechanically-ventilated through a cannula inserted above the carina. The upper tracheal mucosa was exposed, and the electrical potential difference (PD) between the mucosal surface and the submucosal space was continuously measured by a high-impedance voltmeter under open-circuit conditions. Perfusion of the mucosa with atropine caused a rapid decline in PD from -20.1+/-2.0 to -15.2+/-0.9 mV (p<0.01), whereas phentolamine, propranolol, or the tachykinin antagonist, FK224, had no effect. Cutting both cervical vagus nerves decreased PD to the same degree as did atropine. Exogenously applied acetylcholine increased PD in a dose-dependent manner. Topical application of ipratropium bromide reduced the baseline value PD in a dose-dependent manner. The maximal decrease in PD was 43 +/- 0.3 mV (p<0.01), and the dose required to produce a half-maximal effect was 34 microg. Perfusion with either amiloride, a Na channel blocker, and diphenylamine-2-carboxylate, a Cl channel blocker, decreased the baseline PD, and the subsequent application of ipratropium bromide further decreased the PD in each case. We conclude that a cholinergic neural component may play a role in the generation of tracheal potential difference in vivo, probably involving stimulation by endogenously released acetylcholine of both Cl secretion and Na absorption across the airway epithelium.

The FIAU Derivative (2′S)-2′-Deoxy-2′-C-Methyl-5-Iodouridine (SMIU) is a Novel, Less Cytotoxic and Potent anti-HSV and anti-VZV Agent

In this study, the anti-herpetic activities of novel 2′-methyl nucleoside analogues which were substituted at the 5 position of the pyrimidine with a halogen were investigated. The 2′-fluoro-5-iodo-aracytosine (FIAC) congeners (2′S)-2′-deoxy-2′- C-methylcytidine which were substituted with Br or I at the 5 position (SMBC or SMIC); and 2′-fluoro-5-iodo-arauridine (FIAU) congeners (2′S)-2′-deoxy-2′-C-methyluridine which were substituted with Br or I at the 5 position (SMBU or SMIU), proved to have potent antiviral activities against herpes simplex virus type-1 (HSV-1) and varicella-zoster virus (VZV) but not against herpes simplex virus type-2 (HSV-2). SMIU has a higher selective index against HSV-1 than FIAU, and both SMIC and SMIU showed higher inhibitory effects against VZV replication than aciclovir. The four effective compounds were not inhibitory to a thymidine kinase (TK)-negative HSV-1 strain, and this result indicates that phosphorylation of the compounds by HSV or VZV-TK is necessary for the activation of these compounds.

Hypoxia impairs nitrovasodilator-induced pulmonary vasodilation: role of Na-K-ATPase activity

To elucidate the effect of hypoxia on nitrovasodilator-induced pulmonary vasodilation, we studied canine pulmonary arterial rings under isometric conditions in vitro. Exposure to hypoxia inhibited the relaxant responses of KCl-contracted tissues to sodium nitroprusside (SNP), so that the maximal relaxation (Emax) and the negative logarithm of molar concentration required to produce 50% relaxation (pD2) were decreased from 92 +/- 7 to 62 +/- 5% and from 5.8 +/- 0.2 to 4.7 +/- 0.3, respectively (means +/- SE, P < 0.01 for each). This effect was likewise observed when 8-bromoguanosine-3',5'-cyclic monophosphate was used as a relaxant. The impairment of SNP-induced relaxation of endothelium-denuded rings under hypoxia was abolished by ouabain or K(+)-free solution. Incubation with SNPincreased intracellular cGMP contents in a dose dependent manner, an effect that was not altered by hypoxia. SNP also increased ouabain-sensitive 86Rb uptake, and this effect was inhibited by hypoxia. These results suggest that hypoxia reduces nitrovasodilator-induced relaxation of pulmonary artery, probably through an inhibition of cGMP-dependent sarcolemmal Na-K-adenosine triphosphatase activity.

Effects of roxithromycin and erythromycin on interleukin 8-induced neutrophil recruitment and goblet cell secretion in guinea pig tracheas

Inhaled interleukin 8 caused an increase in goblet cell secretion in guinea pig tracheas, which was accompanied by mucosal infiltration of neutrophils. These responses were inhibited by pretreatment with roxithromycin or erythromycin in a dose-dependent fashion. Macrolides may thus be a value in protecting against neutrophil-associated airway hypersecretion.

Effect of oxitropium bromide on histamine-induced airway goblet cell secretion

To determine whether histamine affects airway goblet cell secretion and, if so, whether cholinergic mechanism is involved, we studied guinea pig airways by a semiquantitative morphometric method. The goblet cell secretion was assessed in histologic sections of the tracheal mucosa stained with Alcian blue and periodic acid-Schiff (PAS) by determining the mucus score, which is inversely related to the magnitude of mucus discharge. Inhaled or intravenously administrated histamine dose dependently decreased the mucus score, an effect that was similarly observed in cartilaginous and muscular portions. Inhalation of the anticholinergic agent oxitropium bromide at doses of 1.5 micrograms and higher greatly attenuated the decrease in mucus score produced by intravenous histamine but not by inhaled histamine. Likewise, cutting of bilateral vagus nerves or atropine abolished intravenous histamine-induced goblet cell secretion. The response of the mucus score to inhaled histamine was abolished by cimetidine, whereas the response to intravenous histamine was reduced by mepyramine but not by cimetidine or thioperamide. These results suggest that inhaled histamine increases airway goblet secretion, probably by stimulating histamine H2-receptors on goblet cells, and that intravenous histamine produces a similar effect through a stimulation of histamine H1-receptor-mediated release of acetylcholine from cholinergic nerve terminals, presumably involving vagal reflex.

Effect of ciprofloxacin on ciliary motility of rabbit airway epithelium

To determine the effect of the new quinolone ciprofloxacin on airway ciliary motility, we studied ciliary beat frequency (CBF) of rabbit tracheal epithelium using an in-vitro microphoto-oscillation method. Incubation of the cells with ciprofloxacin increased CBF in a concentration-dependent manner, the maximal increase from the baseline value and the EC50 being 17.1 +/- 2.0% (P < 0.01) and 10(-7.25) M, respectively. This ciliary stimulatory effect was not affected by propranolol or indomethacin but was nullified by verapamil. These results suggest that ciprofloxacin probably increases airway epithelial ciliary motility by facilitating Ca2+ influx through a voltage-dependent channel.

Effect of 5-hydroxytryptamine on bioelectric properties of airway epithelial cells in culture

To elucidate whether 5-hydroxytryptamine (5-HT) affects airway epithelial electrolyte transport and, if so, what the mechanism of action is, we studied the bioelectric properties of canine cultured tracheal epithelium under short-circuit conditions in vitro. Mucosal addition of 5-HT dose-dependently increased short-circuit current (Isc), which was accompanied by increases in transepithelial potential difference and cell conductance. In contrast, 5-HT had no effect on bioelectric properties when it was added to the submucosal side. Pretreatment of cells with amiloride potentiated the increase in Isc produced by 5-HT. In the presence of diphenylamine-2-carboxylate or Cl-free medium, 5-HT decreased Isc from the baseline level. Incubation with BAPTA-AM but not dibutyryl cAMP greatly attenuated the 5-HT-induced increase in amiloride-insensitive portion of Isc. These results suggest that 5-HT inhibits Na absorption and stimulates Cl secretion across canine tracheal epithelium and that the Cl secretion may be associated with elevation of intracellular Ca2+ contents.

[Regulation of cyclooxygenase activity in airway epithelium by endogenous nitric oxide]

The role of nitric oxide (NO) in the activity of cyclooxygenase (COX) in cultured canine tracheal epithelium was studied. Tracheal epithelium spontaneously released prostaglandin E2 (PGE2), which is a product of COX. The release of PGE2 was increased by bradykinin and was decreased by two NO synthase inhibitors: NG-nitro-L-arginine methyl ester and NG-monomethyl-L-arginine. That decrease was reversed in the presence of L-arginine. Chrolpromadin, but not aminoguanidine, inhibited PGE2 production, which suggests that constitutive NO synthase is involved. Two stable NO donors, sodium nitroprusside and S-nitroso-N-acetyl DL-penicillamine, also increased the production of PGE2. These effects were abolished by coincubation with hemoglobin, which binds and inactivates NO, but not by methylene blue, an inhibitor of soluble guanylate cyclase. NADPH diaphorase histochemistry of cultured tracheal cells revealed activity in the periphery of the cytoplasm. These results suggest that, in cultured canine tracheal epithelium, NO directly interacts with COX to regulate PGE2 production.

[Effect of macrolide antibiotics on airway goblet hypersecretion in guinea pigs]

Although macrolide antibiotics have now been widely used in the treatment of chronic airway infections including diffuse panbronchiolitis and chronic bronchitis, the mechanism of the efficacy remains uncertain. Because the increased mucus glycoprotein secretion from airway goblet cells may play a significant role in the development of such diseases, to determine the effects of macrolides on airway goblet cell secretion, we studied guinea pig airways by a semiquantitative morphometric method. The goblet cell secretion was assessed in histological sections of the trachea and main bronchi stained with Alcian blue and PAS by determining mucus score, which is inversely related to the magnitude of mucus discharge. Intravenous IL-8 decreased mucus score in a dose-dependent manner and increased the number of neutrophils present in bronchoalveolar lavage fluid. Oral administration of clarithromycin at a daily dose of 1-10 mg/day for 2 weeks dose-dependently inhibited IL-8 (5 mg/ kg)-induced decrease in mucus score, with the maximal inhibition being 54 +/- 11% (p < 0.001) in the trachea and 48 +/- 8% (p < 0.01) in the main bronchi. This effect was accompanied by the inhibition of neutrophil accumulation into bronchoalveolar lavage fluid. Erythromycin produced similar inhibitory effects on IL-8-induced goblet cell secretion and neutrophil accumulation, whereas amoxicillin and cefaclor had no effect. These results suggest that macrolides protect against goblet cell hypersecretion probably through an inhibition of recruitment of neutrophils into the airway mucosa.

[Pleural fibroma with a cavity-like air space]

A 45-year-old man was admitted to the hospital because of an increase in the size of an abnormal shadow on chest X-ray films over the preceding 5 years. A chest X-ray film on admission revealed a round air space in a mass-like shadow in the right upper lung field. Results of physical examination, sputum cytologic examination, and Ziehl-Neelsen staining were negative. Histopathological examination of a percutaneous lung biopsy specimen revealed a benign fibrous tumor of the pleura. Thoracotomy revealed a pedunculated tumor arising from the visceral pleura at the apical segment of the right upper lobe. A wedge resection was done. Histological examination revealed that the tumor consisted of regularly-shaped spindle cells with densely collagenous tissue. Normal lung tissue was found to be invaginated into the tumor tissue. These findings are consistent with the radiologic findings.

[T-kinin-induced increase in airway vascular permeability and its modulation by angiotensin-converting enzyme]

We studied the effect of T-kinin on airway vascular permeability and its modulation by endogenous peptidases in anesthetized rats in vivo, Vascular permeability was assessed by photometric measurement of extravasated Evans blue dye after formamide extraction. Intravenous injection of T-kinin increased dye extravasation in the trachea and main bronchi in a dose-dependent manner. Plasma extravasation evoked by T-kinin was inhibited by Hoe 140, a B2 receptor but-not by des Arg9-Leu8-bradykinin, a B1 receptor antagonist. Treatment with captopril, an angiotensin-converting enzyme inhibitor, potentiated the T-kinin-induced plasma extravasation, whereas phosphoramidon, a neutral endopeptidase inhibitor, had no effect. These results suggest that T-kinin increases airway vascular permeability via stimulation of B2 receptors, and that this effect is modulated by endogenous angiotensin-converting enzyme.

Anti-HIV-1 activity of thiadiazole derivatives: structure-activity relationship, reverse transcriptase inhibition, and lipophilicity

The structure-activity relationship of the non-nucleoside HIV-1-specific reverse transcriptase (RT) inhibitors 4-phenyl-1,2,5-thiadiazol-3-yl N,N-dialkylcarbamate (TDA) derivatives was investigated with respect to their anti-HIV-1 activity, RT inhibition, and lipophilicity. 4-Phenyl-1,2,5-thiadiazol-3-yl N,N-dimethylcarbamate inhibited HIV-1-induced cytopathic effect (CPE) by 50% at a concentration of 28.8 microM in MT-4 cells. The activity increased more than 100-fold when the hydrogens at the 2-position and the 6-position in phenyl moiety were substituted by chlorines. However, the derivative with a chlorine at the 4-position of phenyl moiety did not show any inhibition of HIV-1 replication at its non-toxic concentrations. All of the 4-(2,6-dichlorophenyl)-1,2,5-thiadiazol-3-yl N-methyl-N-alkylcarbamates proved inhibitory to HIV-1 replication in the nanomolar concentration range. The TDA derivatives that showed anti-HIV-1 activity also inhibited RT activity in an enzymatic assay. However, the TDA derivatives did not show any specific inhibition of a non-nucleoside RT inhibitor (NNRTI)-resistant mutant and its RT activity. When the TDA derivatives were examined for their inhibitory effect on HIV-1 replication in the presence of 50% human serum, the activity significantly decreased depending on-their lipophilicity.

Antiviral activities of nucleotide heterodimers against human immunodeficiency virus type 1 in vitro

Nucleotide heterodimers were synthesized and examined for their inhibitory effects on the replication of human immunodeficiency virus type 1 (HIV-1), including HIV-1 reverse transcriptase (RT) inhibitor-resistant mutants. 3'-Azido-3'-deoxythymidilyl-(5')-phospho-(5')-6-[(3', 5'-dimethylphenyl)thio]-5-ethyl-1-[(2-hydroxyethoxy)methyl]uracil (AZT-P-E-HEPU-dM) and 3'-azido-3'-deoxythymidilyl-(5')-phospho-(5')-2', 3'-dideoxyinosine (AZT-P-ddI) proved to be highly potent and selective inhibitors of HIV-1 (IIIB strain) in MT-4 cells. The mechanism of inhibition by these heterodimers may be attributed to their degradation and the formation of each constituent. AZT-P-E-HEPU-dM was also markedly inhibitory to an AZT-resistant mutant (HIV-1-IIIB/AZT) and an E-HEPU-dM-resistant mutant (HIV-1-IIIB-R). However, AZT-P-ddI was found to have a less inhibitory effect on HIV-1-IIIB/AZT than on HIV-1-IIIB. The heterodimers of (5',5') AZT and ribavirin (AZT-P-Ribavirin) and (5',5') ddI and ribavirin (ddI-P-Ribavirin) were also synthesized: AZT-P-Ribavirin inhibited HIV-1 replication, but ddI-P-Ribarvirin did not.

Zizyphi fructus, a constituent of antiasthmatic herbal medicine, stimulates airway epithelial ciliary motility through nitric oxide generation

The effects of Zizyphi fructus, a major constituent of Chinese anti-asthmatic herbal medicine, on ciliary motility and nitric oxide (NO) generation in canine cultured tracheal epithelium were studied by the microphoto-oscillation method and the specific amperometric method, respectively. Addition of Zizyphi fructus at 100 micrograms/mL rapidly increased ciliary beat frequency (CBF), an effect that was inhibited by NG-nitro-L-arginine methylester (L-NAME) but not by NG-nitro-D-arginine methylester (D-NAME), and this inhibition was reversed by L-arginine but not by D-arginine. Immersion of the NO-selective electrode in the medium bathing tracheal epithelial cells showed a baseline current of 21.3-60.4 pA, which corresponded to NO concentration ([NO]) at 34.4 +/- 7.8 nM. Zizyphi fructus caused a concentration-dependent increase in [NO], the maximal increase from the baseline [NO] level and the concentration of Zizyphi fructus required to produce a half-maximal effect (EC50) being 107 +/- 14 nM (p < .001) and 7.2 +/- 2.9 micrograms/mL, respectively. These results suggest that Zizyphi fructus enhances airway ciliary motility and that this effect is exerted through the stimulation of epithelial NO generation.

Different properties of wild type and drug-resistant mutants of human immunodeficiency virus type 1 reverse transcriptase in vitro

Drug-resistant mutants of human immunodeficiency virus type 1 (HIV-1) emerge during treatment with various reverse transcriptase (RT) inhibitors in vitro and in vivo. However, the virological nature and pathogenic importance of these mutants have not been fully elucidated. In this study, we have examined HIV-1 mutants resistant to 3'-azido-3'-deoxythymidine (AZT) and nonnucleoside RT inhibitors (NNRTIs) for their infectivity, RT activity, and replication in MT-4 cells. Although the infectivity of AZT- and NNRTI-resistant mutants was similar, the RT activity of AZT-resistant mutants was much higher than that of NNRTI-resistant mutants and their wild types. Furthermore, the RT activity of NNRTI-resistant mutants was significantly lower than that of the wild types. In contrast, the replication of NNRTI-resistant mutants was found to be greater than that of AZT-resistant mutants and the wild types. When HIV-1 proviral DNA (cDNA) synthesis was examined by PCR in MT-4 cells infected with the wild type, AZT-resistant mutant, or NNRTI-resistant mutant, the PCR signal of the NNRTI-resistant mutant was found to be much higher than those of the wild type and AZT-resistant mutant. These results suggest that the drug-resistant mutants differ from their corresponding wild types not only in drug sensitivity but also in other virological properties.

Inhibitory effect of 4-(2, 6-dichlorophenyl)-1, 2, 5-thiadiazol-3-yl-N-methyl, N-ethylcarbamate on replication of human immunodeficiency virus type 1 and the mechanism of action

In the search for effective antiviral agents, we have found 4-(2, 6-dichlorophenyl)-1, 2, 5-thiadiazol-3-yl-N-methyl, N-ethylcarbamate (RD4-2025) to be a highly potent and selective inhibitor of human immunodeficiency virus type 1 (HIV-1) in vitro. The 50% effective concentration of RD4-2025 for HIV-1-induced cytopathic effect in MT-4 cells was 37 nM, yet no antiviral activity was observed against HIV-2. In HIV-1 reverse transcriptase (RT) assays, RD4-2025 inhibited both RNA-dependent and DNA-dependent DNA polymerase activities of a recombinant HIV-1 RT with 50% inhibitory concentrations of 0.11 and 3.5 microM, respectively. However, the compound did not affect the activity of human DNA polymerase alpha. Kinetic studies revealed that the inhibition was noncompetitive with respect to dGTP as the substrate and poly(C)/(dG) 12-18 as the template/primer. These results were in accordance with those of nonnucleoside RT inhibitors (NNRTIs), such as R89439 (an alpha-anilinophenylacetamide derivative) and nevirapine, indicating that RD4-2025 also belongs to the family of NNRTIs.

[Methicillin-resistant Staphylococcus aureus infection in the Akita University Hospital: surveillance and microbiology data]

In order to control the nosocomial infections by methicillin-resistant Staphylococcus aureus (MRSA) in the Akita University Hospital, the systematic surveillance for MRSA-infection has been done since October in 1991. We reviewed MRSA-isolation numbers, MRSA-detected patient numbers, risk factors of nosocomial infection and patient's basic diseases with the data of a total 336 cases, and then examined the microbiological characteristics of MRSA strains which had been isolated in our hospital in 1986 approximately 1994. The results obtained are as follows; 1) MRSAs were isolated at 13 per month on the average and the detection rate was 0.81 to 1,000 inpatients per day. 2) MRSAs were isolated more in the surgical ward. 3) Patients with 0 year old and more than 60 years old were more infected. 4) MRSA was isolated more from the immunocompromised patients with underlying diseases such as malignant tumors but half of the diseases were not affected by MRSA. 5) Seventy percent of patients had the risk factors of MRSA-transmission such as surgical operation and IVH-cathetering. 6) All isolates of MRSA strains in our hospital showed type II in coagulase type analysis and resistance to minocycline and ofloxacin. 7) It was suggested that one strain expanded throughout the hospital by several DNA analysis with the mecA gene in MRSA. These surveillance and microbiology data will be useful for our nosocomial mecA gene in MRSA. These surveillance and microbiology data will be useful for our nosocomial infection control.

Alveolar destruction in guinea pigs chronically exposed to diesel engine exhaust. A light- and electron-microscopic morphometry study

Guinea pigs were exposed 16 h a day, 6 d a week, for 6, 12, 18, or 24 mo to filtered air or diesel-exhaust at low (NO2 = 0.22 +/- 0.03 ppm; SO2 = 0.60 +/- 0.19 ppm; particles = 0.21 +/- 0.07 mg/m3), medium (NO2 = 1.07 +/- 0.09; SO2 = 2.83 +/- 0.73; particles = 1.14 +/- 0.26) or high (NO2 = 2.88 +/- 0.29; SO2 = 6.49 +/- 1.75; particles = 2.94 +/- 0.69) concentrations, or at a medium concentration without particles (NO2 = 1.01 +/- 0.09; SO2 = 2.66 +/- 0.64; particles = 0.01 +/- 0.01). We quantitated the holes in the alveolar wall and alveolar size by using scanning electron microscopy (SEM). After 12 mo of exposure, the ratio of the area of alveolar holes to that of the alveolar wall, and the number of holes per alveolus, rose as the concentration and duration of exposure increased. There were no differences in alveolar size between the study groups. Animals exposed to the medium concentration of diesel exhaust without particles showed less of an increase in the development of holes than animals exposed to the same concentration of diesel exhaust with particles. These findings suggest that diesel exhaust causes alveolar destruction (alveolar holes) without an enlargement in alveolar size in a concentration- and duration-dependent manner. Particulate matter in diesel exhaust may play some role in the development of these lesions.

Nicotine prolongs neutrophil survival by suppressing apoptosis

Neutrophil accumulation in the lung is implicated in the pathogenesis of pulmonary emphysema and chronic bronchitis associated with cigarette smoking. To determine whether nicotine contributes to this accumulation through the prolongation of neutrophil survival, we examined the survival rates of isolated neutrophils cultured with or without nicotine. We found that nicotine prolonged neutrophil survival in a dose-dependent fashion, with a maximum effect at 10(-6) mol/L. The survival rate at 72 hours was 35.6% +/- 1.2% in medium with 10(-6) mol/L nicotine, compared with 15.5% +/- 0.5% in control medium (mean +/- SEM; p < 0.01), as determined by trypan blue dye exclusion. This prolongation was brought about by suppression of apoptosis, as evidenced by both transmission electron and fluorescence microscopy, and was associated with the preservation of neutrophil functions such as chemotaxis and O2- generation. The prolongation of survival caused by nicotine was abrogated by the addition of Pro-Lys-Arg-NH2, a competitive inhibitor of the specific binding of nicotine to noncholinergic receptors on neutrophils. However, the prolongation of survival caused by nicotine was not suppressed in the presence of K-252b, an inhibitor of protein kinase C. These findings suggest that nicotine prolongs neutrophil survival through noncholinergic nicotine receptors and new protein synthesis, without activation of protein kinase C.

Colorimetric assay system for screening antiviral compounds against hepatitis B virus

A highly sensitive, rapid, and accurate assay system was developed for the in vitro evaluation of anti-hepatitis B virus (anti-HBV) agents. Chronic HBV-producing HB611 cells were used in combination with immunoaffinity purification, polymerase chain reaction (PCR), and hybrid capture detection. HB611 cells were incubated with putative anti-HBV agents for 7 days in 96-well microtiter plates. HBV was purified from HB611 cell culture media using immunoaffinity purification. The HBV DNA was extracted, amplified with PCR, and assayed using a hybrid capture colorimetric method. This assay provided quantitative detection of extracellular HBV DNA from 25 microliters of cell culture media. Using the colorimetric method, we found that 50% effective concentration levels of several known anti-HBV agents (HPMPA, PMEDAP, PMEA and others) were similar to those reported in studies using Southern blot analysis. These results demonstrate that this new and easily automated colorimetric assay system can be used for the rapid and accurate assessment of anti-HBV compound selectivity.

Mechanism of selective inhibition of human immunodeficiency virus by ingenol triacetate

Ingenol 3,5,20-triacetate (ITA), one of the ingenol derivatives, is a selective inhibitor of human immunodeficiency virus (HIV) replication in vitro. ITA inhibited the replication of HIV strains in MT-4 cells at concentrations of 0.051 to 0.65 microM. This concentration was approximately 10(3)-fold lower than its cytotoxic threshold. The mechanism of action of ITA is primarily attributed to the inhibition of viral adsorption to the host cells, but it is distinct from the mechanism of inhibition by other adsorption inhibitors.

Lipoxin A4 inhibits cholinergic neurotransmission through nitric oxide generation in the rabbit trachea

The effect of lipoxin A4 and lipoxin B4 on cholinergic neurotransmission in rabbit tracheal segments was studied under isometric conditions in vitro. Lipoxin A4 attenuated the contractile responses to electrical field stimulation and caused a rightward shift of the frequency-response curves, so that the stimulus frequency required to produce a half-maximal effect (ES50) increased from 8.1 +/- 0.8 to 25.7 +/- 1.9 Hz (P < 0.001), whereas lipoxin B4 had no effect. In contrast, lipoxin A4 did not alter the contractile responses to acetylcholine. Pretreatment of tissues with NG-nitro-L-arginine methylester inhibited the effect of lipoxin A4 on electrical field stimulation, but NG-nitro-D-arginine methylester did not. This inhibition by NG-nitro-L-arginine methylester was reversed by L-arginine but not by D-arginine. These results suggest that lipoxin A4 prejunctionally reduces the vagal nerve-mediated contraction of airway smooth muscle, probably by inhibiting the release of acetylcholine, and that this effect may be exerted through stimulation of nitric oxide generation.

Tachykinins stimulate nitric oxide generation by canine cultured tracheal epithelium

We studied the effects of tachykinins on the generation of nitric oxide (NO) from canine cultured tracheal epithelial cells using a specific amperometric sensor for this molecule. Immersion of the NO-selective electrode in the medium bathing the cells detected the baseline current of 30.5-61.7 pA, which corresponded to NO concentration ([NO]) at 44.0 +/- 7.6 nM (mean +/- S.E.M.). Substance P (SP, 10(-6) M) increased the current from 51.3 +/- 9.8 to 73.6 +/- 11.4 pA (P < 0.001), an effect that was not affected by NG-nitro-D-arginine methylester, but inhibited by NG-nitro-L-arginine methylester by 83 +/- 9% (P < 0.001), and this inhibition was restored by the subsequent addition of L-arginine, but not by D-arginine. SP and neurokinin A (NKA) increased [NO] in a dose-dependent manner, the maximal increases from the baseline level being 71.0 +/- 14.9 and 33.4 +/- 8.5 nM, respectively (P < 0.001 for each), whereas neurokinin B (NKB) had no effect. In the presence of phosphoramidon, the response of each tachykinin was augmented, but the rank order of potency was still NKA > SP >> NKB. These results suggest that NO is spontaneously released from airway epithelium and that tachykinins stimulate epithelial NO generation via NK2 receptors.

Stimulation of opioid mu-receptors potentiates beta adrenoceptor-mediated relaxation of canine airway smooth muscle

To elucidate the effect of an opioid on airway smooth muscle relaxant responses and its mechanism of action, we studied canine bronchial segments under isometric conditions in vitro. Addition of the opioid mu-receptor-specific agonist DAMGO (10(-5) M) or Tyr-D-Arg-phe-Lys-NH2 (10(-5) M) did not alter the resting tension or the contractile responses to Ach but augmented the relaxation induced by isoproterenol: the concentrations of isoproterenol required to produce a half-maximal effect were decreased from 1.9 +/- 0.6 x 10(-6) to 3.1 +/- 1.0 x 10(-7) M (P < .01) by DAMGO and from 2.1 +/- 0.4 x 10(-6) M to 4.3 +/- 0.7 x 10(-7) M (P < .01), by Tyr-D-Arg-phe-Lys-NH2. This effect of DAMGO was concentration-dependent and was abolished by naloxone or Cys2, Tyr3, Orn5, Pen7-amide, a mu-receptor antagonist. DAMGO likewise caused a leftward displacement of concentration-response curves for forskolin but was without effect on those for 3-isobutyl-3-methylxanthine and 8-bromo-cAMP. Also, DAMGO did not affect the relaxant responses to verapamil, nitroprusside or 8-bromo-cGMP. Incubation of bronchial smooth muscle with DAMGO (10(-5) M) potentiated the intracellular accumulation of cAMP induced by isoproterenol (10(-6) M) from 258 +/- 22 pmol/g tissue wt. to 420 +/- 27 pmol/g tissue wt. (P < .01), an effect that was abolished by naloxone. These results suggest that stimulation of opioid mu-receptors specifically augments beta adrenoceptor-mediated bronchodilation probably by acting at the site proximal to adenylate cyclase in the cAMP-dependent pathway.

Nitric oxide modulation of Ca2+ responses in cow tracheal epithelium

Nitric oxide (NO) plays an important role in the regulation of Ca2+ -dependent airway epithelial function such as ciliary motility. In this experiment, the effect of NO on intracellular Ca2+ ([Ca2+]1) was studied in cultured cow tracheal epithelium by the fura-2 method. L-NG-nitroarginine methyl ester, an NO synthase inhibitor, per se did not significantly alter baseline [Ca2-]i, but bradykinin- and ATP-induced increases in [Ca2+]i were significantly reduced in the presence of L-NG-nitroarginine methyl ester. This inhibitory effect disappeared by a simultaneous addition of L-arginine. Sodium nitroprusside or dibutyryl cyclic GMP potentiated bradykinin- and ATP-induced increases in [Ca2+]i. Cytochemistry for NADPH diaphorase activity revealed the presence of NO synthase in the cultured epithelium. These results suggest that NO produced by NO synthase in airway epithelium modulates bradykinin- and ATP-induced [Ca2+]i responses, which may be dependent on cyclic GMP.

Potent and specific inhibition of human immunodeficiency virus type 1 replication by 4-(2,6-dichlorophenyl)-1,2,5-thiadiazol-3-Y1 N,N-dialkylcarbamate derivatives

4-(2,6-Dichlorophenyl)-1,2,5-thiadiazol-3-yl N,N-dialkylcarbamate (TDA) derivatives were found to be highly potent and specific inhibitors of human immunodeficiency virus type 1 (HIV-1) replication in a variety of cell cultures. The most potent congener of TDA derivatives, RD4-2024, inhibited HIV-1 replication by 50% at concentrations of 12.5 and 4.8 nM in MT-4 cells and peripheral blood mononuclear cells, respectively. These concentrations were more than 2,000- and 30,000-fold lower than its 50% cytotoxic concentrations, respectively. Although the TDA derivatives were active against 3'-azido-3'-deoxythymidine-resistant HIV-1, no antiviral activities were observed against HIV-2 and nonnucleoside reverse transcriptase inhibitor-resistant mutants of HIV-1. The TDA derivatives inhibited recombinant HIV-1 reverse transcriptase activity, depending on the template-primer used for the assay. However, they did not interact with HIV-2 reverse transcriptase. Thus, the TDA derivatives belong to the family of nonnucleoside reverse transcriptase inhibitors. Because of their potent anti-HIV-1 activities in vitro and their low levels of toxicity in mice, the TDA derivatives deserve further evaluation as candidate drugs for the treatment of patients with AIDS.

Role of nitric oxide in tachykinin-induced increase in potential difference of rabbit tracheal mucosa

1. The effect of tachykinins on transepithelial potential difference (PD) of rabbit trachea and possible involvement of nitric oxide (NO) generation in vivo were investigated. 2. Perfusion of tracheal mucosa with neurokinin A (NKA) or substance P (SP) dose dependently increased PD in the presence of amiloride, with the potency being NKA > SP, but neurokinin B (NKB) had no effect. 3. Application of NG-nitro-L-arginine methylester (L-NAME, 10(-3) M) attenuated the NKA-induced increase in the amiloride-sensitive PD, causing a rightward displacement of the dose-response curve by approximately 1.0 log U, whereas NG-nitro-D-arginine methylester (D-NAME, 10(-3) M) did not. 4. The inhibitory effect of L-NAME was reversed by L-arginine (10(-2) M) but not by D-arginine (10(-2) M). 5. The release of NO was determined by a real-time measurement of NO concentration ([NO]) in the perfusate using specific amperometric sensors for this molecule. 6. NKA and SP increased [NO] in a dose-dependent manner, the maximal increase from the baseline value being 114 +/- 11 nM (mean +/- S.E.M., P < 0.001) and 54 +/- 6 nM (P < 0.01), respectively. 7. Histochemistry for NADPH diaphorase activity showed a strong staining within the epithelial cells. 8. We conclude firstly that tachykinins increase amiloride-sensitive PD in vivo, which probably reflects Cl- movement from the submucosa toward the respiratory lumen in tracheal mucosa, and secondly that NO generation by epithelial cells may be involved in this process.

Cyclic adenosine monophosphate-mediated release of nitric oxide from canine cultured tracheal epithelium

Nitric oxide (NO) may play a part in pulmonary vascular regulation and bronchomotor control and has been detected in exhaled air. We report the release of NO from airway epithelial cells and its regulation by cyclic adenosine monophosphate (cAMP). To directly measure NO release, a highly specific amperometric sensor for NO made of Pt/Ir alloy coated with a three-layered membrane consisting of KCI, NO-selective resin, and normal silicon resin was developed. Immersion of this sensor in the medium containing canine cultured tracheal epithelium detected baseline levels of NO at 9.6 +/- 1.6 nM (mean +/- SE), which was reduced by NG-nitro-L-arginine methylester (L-NAME) but not by D-NAME. This inhibition was reversed by L-arginine. Addition of isoproterenol, 3-isobutyl-1-methylxanthine, and forskolin caused a rapid increase in NO, an effect that was not altered by Ca(2+)-free medium in the presence of the intracellular Ca2+ chelator BAPTA-AM and the calmodulin antagonist W-7. Bradykinin, ionomycin, and ATP were without effect on NO release. The forskolin-induced NO release was accompanied by intracellular accumulation of cAMP and Ca2+. In contrast, bradykinin increased intracellular Ca2+ but not cAMP levels. Cytochemistry of cultured tracheal epithelium showed a positive staining with NADPH diaphorase activity. These results suggest that airway epithelial cells spontaneously release NO and that the release may be stimulated specifically through cAMP-dependent mechanism.

Effect of T-kinin on microvascular permeability and its modulation by peptidases in rat airways

T-kinin (Ile-Ser-bradykinin), the product of T-kininogen, has been found in rat plasma during systemic inflammation, but the effect of this kinin on airway inflammatory response is unknown. We examined the effect of T-kinin on vascular permeability in airways of anesthetized rats in vivo by using photometric measurement of the extravasated Evans blue. Intravenous injection of T-kinin (0.1-10 mumol/kg) increased dye extravasation in a dose-dependent manner, with 134% for trachea and 117% for bronchi by 1 mumol/kg. Pretreatment with bradykinin B2-receptor antagonist Hoe-140 (100 nmol/kg), but not the B1-receptor antagonist des-Arg9-Leu8-bradykinin (5 mg/kg), abolished plasma extravasation evoked by T-kinin (1 mumol/kg). NK1 tachykinin-receptor antagonist CP-99994 (4 mg/kg) did not affect T-kinin-induced vascular leakage. Pretreatment with captopril (2.5 mg/kg), angiotensin-converting enzyme inhibitor, potentiated T-kinin (100 nmol/kg)-induced plasma extravasation, whereas phosphoramidon (2.5 mg/kg), a neutral endopeptidase inhibitor, had no effect. We conclude that T-kinin produces airway vascular extravasation via stimulation of B2 receptors. The effect is modulated by endogenous angiotensin-converting enzyme and is not mediated via activation of sensory nerve.

Regulation of airway cholinergic neurotransmission by Ca(2+)-activated K+ channel and Na(+)-K+ adenosinetriphosphatase

Stimulation of Ca(2+)-activated K+ channel and Na(+)-K(+)-ATPase may play an important role in the relaxant responses of airway smooth muscle to certain bronchodilators. To test whether cholinergic neuroeffector transmission can be modulated by Ca(2+)-activated K+ channel and Na(+)-K(+)-ATPase, canine airway smooth muscle was studied under isometric conditions in vitro. Addition of charybdotoxin (10(-7) M) did not alter the contractile responses to acetylcholine but augmented electrical field stimulation-induced contractions at 1-10 Hz (p < .01), whereas apamin and glibenclamide were without effect. This effect of charybdotoxin was dose dependent, with the maximal increase being 36.8 +/- 5.3% (p < .001). Ouabain (10(-7) M) increased contractions induced by both electrical field stimulation and acetylcholine. The magnitude of the increase in contractile responses to electrical field stimulation was similar to that of acetylcholine at an ouabain concentration of up to 3 x 10(-7) M, but the former was significantly greater at 10(-6) M ouabain (p < .05). These results suggest that both Ca(2+)-activated K+ channel and Na(+)-K(+)-ATPase may be operative in the regulation of cholinergic neurotransmission by inhibiting the exocytotic release of acetylcholine from the vagal nerve terminals.

Effect of saiboku-to, an antiasthmatic herbal medicine, on nitric oxide generation from cultured canine airway epithelial cells

The effect of Saiboku-to (TJ-96), an antiasthmatic Kampo medicine, on the generation of nitric oxide (NO) from cultured canine tracheal epithelium was investigated using a highly specific amperometric sensor for this molecule in vitro. Immersion of the NO-selective electrode in the medium containing tracheal epithelial cells detected the baseline current of 16.8-57.0 pA, which corresponded to an NO concentration ([NO]) of 39.7 +/- 8.1 nM. Addition of TJ-96 increased [NO] in a concentration-dependent manner, the maximal increase from the baseline level and the concentration of TJ-96 required to produce a half-maximal effect (EC50) being 127.5 +/- 20.1 nM (P < 0.001) and 86 +/- 9 micrograms/ml, respectively. Pretreatment of cells with NG-nitro-L-arginine methylester (L-NAME) greatly inhibited the TJ-96-induced increase in [NO], whereas NG-nitro-D-arginine methylester (D-NAME) had no effect, and this inhibition was reversed by L-arginine but not by D-arginine. Cytochemical staining of the epithelial cells showed marked reactivity of NADPH diaphorase activity. These results suggest that NO is spontaneously released by the airway epithelium and that TJ-96 stimulates the epithelial NO generation.

A specific neutrophil elastase inhibitor (ONO-5046.Na) attenuates LPS-induced acute lung inflammation in the hamster

We have examined the effect of ONO-5046.Na, a synthetic specific inhibitor of neutrophil elastase, on lipopolysaccharide (LPS)-induced acute lung inflammation. Syrian golden hamsters were injected intraperitoneally with either 300 mg.kg-1 of ONO-5046.Na or saline, 30 min before and 1 h after intratracheal administration of 0.1 mg.kg-1 LPS. Animals were sacrificed 2 and 24 h later and the wet-to-dry lung weight ratio (W/D) was determined. Bronchoalveolar lavage (BAL) was performed, and tissue sections were examined histologically. The effect of ONO-5046.Na on migration of isolated neutrophils was determined. W/D was not significantly different at 2 h, but was increased at 24 h in the LPS-treated animals. This increase was attenuated in the LPS-treated animals injected with ONO-5046.Na. Analysis of BAL fluid revealed that both at 2 and 24 h after LPS administration the total cell number and neutrophil number, albumin concentration, and elastase-like activity were significantly lower in the LPS-treated animals injected with ONO-5046.Na than in those given LPS alone. Histological examination of the lungs of the animals treated with LPS alone showed intra-alveolar haemorrhages and inflammatory cell infiltration 24 h after LPS administration, whereas the lungs of the LPS-treated ONO-5046.Na injected animals were only sparsely infiltrated by inflammatory cells, as indicated by the inflammation score.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of clarithromycin on sputum production and its rheological properties in chronic respiratory tract infections

Macrolide antibiotics possess a variety of actions other than antimicrobial activities. To determine the effects of long-term administration of clarithromycin (CAM) on the amount and physical properties of sputum in patients with clinical conditions associated with excessive airway secretions, we conducted the present study in a parallel, double-blind, placebo-controlled fashion. Patients were divided into two groups: the first group (n = 16) received CAM (100 mg, twice a day) for 8 weeks, and the second group (n = 15) received placebo. In evaluating airway secretion, the daily amount of expectorated sputum, solid composition, viscoelastic properties (including elastic modulus and dynamic viscosity), and sputum microbiology were assessed. CAM decreased sputum production from 51 +/- 6 to 24 +/- 3 g/day after treatment, whereas placebo had no effect. The bacterial density and sputum flora were unaltered. In the group receiving CAM, the percent solid composition and elastic modulus increased from 2.44% +/- 0.29% to 3.01% +/- 0.20% and 66 +/- 7 to 87 +/- 8 dyne/cm2 (P < 0.05), respectively, but the dynamic viscosity remained unchanged. These results suggest that long-term treatment with CAM reduces the amount of sputum production, probably by inhibiting airway secretions, and increases sputum elasticity.

Isoproterenol increases Cl diffusion potential difference of rabbit trachea through nitric oxide generation

To determine whether nitric oxide (NO) formation is involved in Cl secretion across airway mucosa in response to beta adrenergic agonists, we studied the effect of isoproterenol (ISO) on the Cl diffusion potential difference of rabbit tracheal mucosa and measured NO formation by a highly specific electrode for this molecule in vivo. Perfusion of ISO on the tracheal mucosal surface increased the Cl diffusion potential difference, as determined in the presence of amiloride, in a dose-dependent fashion, the maximal increase from the base-line value being 12.1 +/- 1.7 mV (P < .001). Application of NG-nitro-L-arginine methylester (10(-3) M) decreased the Cl diffusion potential difference by itself and attenuated the subsequent response to ISO, causing a rightward displacement of ISO concentration-response curves, whereas NG-nitro-D-arginine methylester had no effect. This inhibitory effect of NG-nitro-L-arginine methyl-ester was reversed by L-arginine but not by D-arginine. Addition of ISO dose-dependently increased polarographic current and, hence, NO concentration in the perfusate, the maximal increase from the base-line levels being 178 +/- 10 nM. Histochemistry for NADPH diaphorase activity showed a strong staining within epithelial cells. These results suggest that NO formation may play a role in the beta adrenoceptor-mediated Cl secretion by tracheal mucosa.