Mitotic signaling by beta-amyloid causes neuronal death

Aggregates of beta-amyloid peptide (betaAP), the main constituent of amyloid plaques in Alzheimer's brain, kill neurons by a not yet defined mechanism, leading to apoptotic death. Here, we report that both full-length betaAP((1-40)) or ((1-42)) and its active fragment betaAP((25-35)) act as proliferative signals for differentiated cortical neurons, driving them into the cell cycle. The cycle followed some of the steps observed in proliferating cells, including induction of cyclin D1, phosphorylation of retinoblastoma, and induction of cyclin E and A, but did not progress beyond S phase. Inactivation of cyclin-dependent protein kinase-4 or -2 prevented both the entry into S phase and the development of apoptosis in betaAP((25-35))-treated neurons. We conclude that neurons must cross the G1/S transition before succumbing to betaAP signaling, and therefore multiple steps within this pathway may be targets for neuroprotective agents.-Copani, A., Condorelli, F., Caruso, A., Vancheri, C., Sala, A., Giuffrida Stella, A. M., Canonico, P. L., Nicoletti, F., Sortino, M. A. Mitotic signaling by beta-amyloid causes neuronal death.

Tumor necrosis factor-alpha induces apoptosis in immortalized hypothalamic neurons: involvement of ceramide-generating pathways

To investigate possible effects that may contribute, together with a direct action on neurohormone secretion, to the impairment of gonadal axis function during inflammation, we evaluated the effect of TNF alpha on the growth and viability of GT1-7 hypothalamic neurons and the intracellular transduction pathways involved in these effects. TNF alpha caused a reduction of cell number and an induction of apoptotic death. These effects were mimicked by cell-permeable analogs of ceramide and by neutral or acidic sphingomyelinase. Exposure to acidic sphingomyelinase induced a persistent (up to 48 h) reduction of cell growth and apoptosis, whereas the effect of neutral sphingomyelinase was time limited. The involvement of acidic sphingomyelinase in TNF alpha action was demonstrated by the partial prevention of ceramide generation, apoptosis, and reduced cell growth by the inhibitor of the acidic sphingomyelinase-generating pathway, D609, whereas the involvement of ceramide was proved by complete prevention of TNF alpha-induced effects by treatment with okadaic acid at concentrations inhibiting ceramide-dependent protein phosphatase. The present data indicate that TNF alpha, through activation of ceramide-generating pathways, is able to affect GT1-7 cell viability, suggesting an additional effect that may contribute to the global action of this cytokine on neuroendocrine activities.

Spontaneous pneumomediastinum with subcutaneous emphysema: unusual presenting feature of a common condition

Pneumomediastinum refers to the presence of free air in the mediastinum and is frequently associated with subcutaneous emphysema. It is known that a number of medical and surgical conditions may be complicated by pneumomediastinum. However, here we report the case of a young female in whom pneumomediastinum was the presenting feature of a widespread medical condition rather than its complication.

Time course of changes in adenosine 5'-monophosphate airway responsiveness with inhaled heparin in allergic asthma

BACKGROUND

Recent studies have shown that inhaled heparin exerts a protective effect against various bronchoconstrictor stimuli in asthma, possible through an inhibition of mast cell activation.

OBJECTIVE

Because adenosine 5'-monophosphate (AMP) elicits bronchoconstriction by augmenting mast cell mediator release, we have investigated the effect of inhaled heparin (15,000 units USP/ml, 4 ml) on the bronchoconstrictor response to this agonist and to methacholine in a randomized, double-blind, placebo-controlled study of 10 subjects with asthma. We also carried out a separate randomized, double-blind study in seven additional volunteers with asthma to examine in more detail the time-course of change in bronchial reactivity to inhaled AMP after treatment with nebulized heparin.

RESULTS

Inhaled heparin significantly increased the provocative concentration of AMP causing a 20% decrease in forced expiratory volume in 1 second (PC20 FEV1-AMP) from the postplacebo treatment value of 22.3 mg/ml (range, 5.7 to 68.9 mg/ml) to 48.1 mg/ml (range, 5.1-196.8 mg/ml) (p < 0.01). When compared with placebo, inhaled heparin failed to alter the airway responsiveness to methacholine; the mean (range) PC20 methacholine values were 1.00 mg/ml (0.44 to 4.76 mg/ml) and 1.08 mg/ml (0.46 to 5.08 mg/ml), respectively. After placebo administration, the PC20 AMP values at 15, 60, and 180 minutes did not differ significantly from each other; their geometric mean (range) values were 26.1 mg/ml (5.9 to 85.8 mg/ml), 26.6 mg/ml (6.3 to 87.8 mg/ml), and 24.9 mg/ml (5.2 to 80.2 mg/ml), respectively. When compared with placebo, the PC20 values for AMP after administration of inhaled heparin were significantly increased up to 57.3 mg/ml (14.7 to 176.0 mg/ml) and to 52.7 mg/ml (13.9 to 90.8 mg/ml) at 15 minutes and 60 minutes, respectively. At 180 minutes, inhaled heparin failed to affect AMP airway responsiveness; the PC20 AMP was not significantly different from that of placebo, with a value of 30.6 mg/ml (4.8 to 93.3 mg/ml).

CONCLUSION

Heparin administered by inhalation is effective in attenuating the airway response to AMP but not to methacholine. The time course of change in bronchial reactivity to AMP has a peak effect at 15 minutes and lasts up to 60 minutes. It is possible that the mechanism(s) underlying the protective effects of inhaled heparin in asthma may be related to an inhibitory modulation of mast cell activation.

Nuclear factor-kappaB activation in human monocytes stimulated with lipopolysaccharide is inhibited by fibroblast conditioned medium and exogenous PGE2

The nuclear factor kappaB (NF-kappaB) is thought to be crucially involved in the gene activation of several cytokines, including tumor necrosis factor alpha (TNF). Previously, we showed that fibroblast conditioned medium (FCM) is able to inhibit both TNF mRNA accumulation and protein release in peripheral blood-derived human monocytes (PBM) stimulated with lipopolysaccharide (LPS). In this study we have investigated the effect of FCM on the LPS-induced DNA-binding activity of NF-kappaB, by means of electrophoretic shift assay (EMSA). We provide evidence that FCM strongly inhibits the LPS-induced NF-kappaB activation in PBM. Furthermore, we show that exogenous PGE2 mimics the NF-kappaB inhibitory effect of FCM. On the other hand, FCM produced in the presence of indomethacin does not inhibit NF-kappaB activation by LPS. Our results lend further support to the hypothesis that inflammatory and immune responses of monocytes/macrophages may be modulated at the molecular level by signals originating from tissue structural cells such as fibroblasts.

Human lung fibroblasts inhibit tumor necrosis factor-alpha production by LPS-activated monocytes

Mononuclear phagocytes are important regulators of normal immune, inflammatory, and fibrotic responses. These functions are mediated through the production of several cytokines, including tumor necrosis factor-alpha (TNF-alpha), which regulate the activity of inflammatory and tissue structural cells such as fibroblasts. It is increasingly evident that fibroblasts are also capable of releasing a number of cytokines and soluble factors that can, in turn, interact with monocytes and thereby modulate the inflammatory process. In this study we provide evidence that human lung fibroblasts, through the release of soluble factors such as prostaglandin E2 (PGE2), inhibit both TNF messenger ribonucleic acid (mRNA) accumulation and TNF-alpha protein release by lipopolysaccharide (LPS)-activated human peripheral blood monocytes (PBM). Reverse transcriptase-polymerase chain reaction (RT-PCR) results showed that fibroblast-conditioned medium (FCM) caused a 50% reduction of the TNF-alpha transcript accumulation in LPS-stimulated monocytes. Furthermore, FCM induced a significant decrease in the release of TNF-alpha by LPS-activated PBM. This effect was dependent on the concentration of the FCM and the number of fibroblasts producing it. The maximal effect was seen with monocytes cultured in 100% FCM produced by 2 x 10(6) fibroblasts. This indicated that one or possibly more soluble factors released by fibroblasts were responsible for the effect. Considering that exogenous PGE2 can inhibit TNF-alpha production by PBM, and that fibroblasts are a good source of PGE2, we determined the content of PGE2 in the FCM used in our experiments. We found a good correlation (r = 0.949) between the amount of PGE2 produced by fibroblasts and the degree of TNF-alpha inhibition exerted. In addition, the inhibitory effect of FCM was mimicked by the addition to PBM cultures of exogenous PGE2 in amounts similar to those spontaneously released by fibroblasts in FCM. All of these data suggest a molecular and cellular interaction between PBM and fibroblasts that could contribute to those modulatory mechanisms involved in the self-limitation of the fibrotic process.

The long-term antimicrobial prophylaxis of chronic bronchitis exacerbations

Infectious exacerbations are the major cause of mortality in patients with chronic bronchitis, particularly in elderly subjects. Considering that the preventive use of antibiotics has provided no clear-cut evidence of real efficacy, it has become quite common to use treatments potentially able to stimulate the immune system for prevention of exacerbations of chronic bronchitis. This treatment, based on the oral administration of bacterial extracts, should, at least in theory, stimulate the immune defenses and reduce the incidence of recurring respiratory tract infections. Although during the last few years a good effort to define better the real efficacy and role played by bacterial extracts in chronic bronchitis has been made, their clinical effectiveness is still the subject of debate and the results of some clinical trials are controversial. Particularly, its mechanism of action remains poorly understood, although a huge effort has been made in this direction.

Pulmonary tuberous sclerosis in a woman of child-bearing age with no mental retardation

Tuberous sclerosis is a rare disease characterized by epilepsy, mental retardation and adenoma sebaceum. We describe the case of a 29-year-old woman with a clinical history of tuberous sclerosis who also had severe hypoxaemia, multifocal hamartoma-like lesions of various extrapulmonary organs, massive hypersplenism and coagulation defects. This case emphasizes the value of high resolution computed tomography (HRCT) in patients with pulmonary tuberous sclerosis.

Release of mast-cell-derived mediators after endobronchial adenosine challenge in asthma

Preformed and newly generated mediators released from airway mast cells may play a role in adenosine-induced bronchoconstriction. To investigate the possible role of mast-cell-derived mediator release in mediating bronchoconstriction induced by adenosine 5'-monophosphate (AMP), we have examined the fluid obtained by bronchoalveolar lavage for inflammatory mediators and markers of airway permeability immediately after instillation of AMP directly into an airway segment of 10 asthmatic subjects. Eight subjects completed the protocol. When compared with the saline-challenged segment, the response to endobronchial stimulation with AMP was characterized by a prompt reduction in airway caliber paralleled by a significant rise in PGD2, histamine, and tryptase levels in the lavage fluid. After AMP challenge, the median (range) concentration for PGD2 increased from 36 to 205 pg/ml (p = 0.006), for histamine from 184 to 433 pg/ml (p = 0.018), and for tryptase from 0.30 to 0.54 ng/ml (p = 0.013). In addition, a small but significant rise in albumin levels (from 27.8 to 36.1 micrograms/ml; p = 0.031) was detected after endobronchial challenge with AMP. These findings indicate that adenosine-induced responses may be initiated by the acute release of mast-cell-derived mediators, including PGD2, histamine, and tryptase.

[Mast cell mediator release after endobronchial challenge with adenosine 5'-monophosphate in asthmatic subjects]

Mediator release from activated mast cells is also likely to take place in the asthmatic airways in vivo during adenosine-induced bronchoconstriction. To test this hypothesis, we evaluated mast cell mediator release directly into the airways of 9 asthmatic subjects after endobronchial challenge with adenosine by bronchoalveolar lavage (BAL). The mediators measured were histamine, tryptase, and PGD2. When compared to the saline-challenged segment, the response to AMP instillation was characterized by a prompt reduction in airway calibre paralleled by a significant 4.2-fold increase in PGD2 levels in the BAL fluid (p = 0.004). There were also increases in median histamine (from 200.1 to 433.6 pg/mL) and tryptase levels (from 0.31 to 0.46 ng/mL) recovered after AMP challenge, although they were not significant. These findings support the view that acute bronchospastic response to AMP in asthmatic airways is paralleled by the local release of mast cells derived products, particularly PGD2.

Promotion of eosinophil survival by human bronchial epithelial cells and its modulation by steroids

Accumulation of eosinophils in the bronchial tissue occurs in a variety of inflammatory disorders of the human airway. We asked whether airway epithelial cells released factors that could influence eosinophil survival and thus contribute to accumulation of these cells in the tissues. Using conditioned medium (CM) generated from cultured human bronchial epithelial cells (HBEC), we examined the in vitro survival of eosinophils isolated from human peripheral blood. When cultured in control medium, more than 90% of the eosinophils were dead by day 4. In contrast, culture in HBEC-CM resulted in dose-dependent survival at day 6 of 69 +/- 9.4%, 40.5 +/- 5.9%, and 25 +/- 2% viability with 2, 0.5, and 0.1% HBEC-CM, respectively (n = 4). Granulocyte/macrophage colony-stimulating factor (GM-CSF) was detected in the HBEC-CM by enzyme-linked immunosorbent assay at levels of 22 to 48 pg/ml. Furthermore, preincubation of the HBEC-CM with a neutralizing monoclonal antibody to human GM-CSF completely inhibited this increased survival of eosinophils. Because corticosteroids are potent eosinopenic agents, we also examined the effects of the synthetic steroid budesonide on this system. Budesonide inhibited both spontaneous and interleukin-1 (IL-1)-induced GM-CSF production by cultured HBEC. In addition, preincubation of eosinophils with budesonide caused marked abrogation of the survival induced subsequently with either HBEC-CM or recombinant human GM-CSF. In summary, HBEC can support eosinophil survival via the elaboration of GM-CSF and thus may contribute to the local control of inflammatory cell accumulation. Steroids may modulate this process both by inhibiting cytokine production from HBEC and by a direct effect on eosinophils, preventing their response to cytokines.

Monocyte-macrophage differentiation induced by human upper airway epithelial cells

We examined the ability of conditioned medium (CM) generated by human upper airway epithelial (Ep) cells from normal (NN) and inflamed, allergic rhinitis (AR) and nasal polyp (NP) tissues to induce monocytic differentiation of hemopoietic progenitors of the HL-60 myeloid leukemia cell line in vitro. In HL-60 cells cultured in RPMI with 10% FBS, there was differentiation to 0.4 +/- 0.4% monocytic cells. NN-, AR-, and NP-EpCM induced differentiation to 23 +/- 6%, 42 +/- 11%, and 71 +/- 10% monocytic cells, respectively. EpCM also induced isolated peripheral blood nonadherent mononuclear cells to express monocyte/macrophage-specific antigens as detected by immunohistochemistry using FMC-32 monoclonal antibodies (anti-CD14). We also examined the cytokine content of these EpCMs and found that they contained granulocyte/macrophage colony-stimulating factor (GM-CSF): 126 +/- 35, 198 +/- 22, and 489 +/- 118 pg/ml for NN-, AR-, and NP-EpCM, respectively. These CMs also contained granulocyte-CSF (G-CSF) and interleukin-6 (IL-6), but there were no significant differences between normal and inflamed tissue-derived cell supernatants. No macrophage-CSF (M-CSF) was detected in these EpCMs. Recombinant human GM-CSF, G-CSF, and IL-6, alone and in combinations, at doses similar to or greater than those found in the EpCMs, did not induce comparable monocytic differentiation of HL-60 cells. Preincubation of the EpCM with neutralizing anti-GM-CSF, anti-G-CSF, or anti-IL-6 antibodies did not significantly inhibit the monocytic differentiation induced by the EpCM.(ABSTRACT TRUNCATED AT 250 WORDS)

Neutrophilic differentiation induced by human upper airway fibroblast-derived granulocyte/macrophage colony-stimulating factor (GM-CSF)

We have established primary lines of fibroblasts from nasal polyp (NP) tissues as well as from normal nasal (NN) mucosa and have examined the ability of these cells to release hormone-like peptide messenger molecules (cytokines). Our results show that human upper airway fibroblasts release granulocyte/macrophage colony-stimulating factor (GM-CSF), granulocyte-CSF (G-CSF), and macrophage-CSF (M-CSF) in vitro. We also show that fibroblasts derived from NP tissue express the gene for GM-CSF at a higher level, and release the GM-CSF product in greater amounts, than NN fibroblasts. In addition, we have examined the ability of these fibroblasts and their conditioned medium (CM) to induce differentiation of human hemopoietic progenitor cells. After 7 d, cultures of these cells in RPMI-10% fetal bovine serum contained 5 +/- 2.5% (mean +/- SD) neutrophils. In contrast, culture of progenitor cells with fibroblasts resulted in significantly greater neutrophilic differentiation (18 +/- 4%). Culture in fibroblast-CM induced a similar degree of differentiation, and fibroblast-CM from NP fibroblasts elicited greater differentiation compared to CM from NN fibroblasts (17.5 +/- 3 versus 12 +/- 3%). The neutrophilic differentiation induced by fibroblast-CM can be fully inhibited by preincubating this CM with a monoclonal neutralizing antibody to human GM-CSF. Thus, our results demonstrate: (1) the ability of human upper airway fibroblasts to release GM-, G-, and M-CSF in vitro; (2) that fibroblasts derived from NP tissues express the gene and release the product GM-CSF at greater levels compared to NN fibroblasts; and (3) that fibroblast-derived GM-CSF causes neutrophilic differentiation of human hemopoietic progenitors.

Human upper airway epithelial cell-derived granulocyte-macrophage colony-stimulating factor induces histamine-containing cell differentiation of human progenitor cells

Nasal polyps and allergic rhinitis are upper airway inflammatory conditions characterized by increased numbers of eosinophils and metachromatic cells in the epithelial layer of the nasal mucosa. The objective of the current studies was to investigate the potential contribution of epithelial cells to the accumulation of inflammatory cells in the tissue. We have established pure cultures of human upper airway epithelial cells from normal and inflamed nasal polyps and allergic rhinitis tissue and examined the ability of conditioned medium from these cells (EpCM) to induce differentiation of human hemopoietic progenitors in vitro. We show that, under appropriate culture conditions, EpCMs, particularly those from cells derived from inflamed tissues, induce histamine-containing cell differentiation of cells of the human HL-60 myeloid leukemia cell line. These EpCMs also induce the emergence of both eosinophil/basophil and granulocyte/macrophage colonies in methylcellulose cultures of human peripheral blood mononuclear cells. We also show that CMs from epithelial cells derived from inflamed tissues contain greater amounts of granulocyte-macrophage colony-stimulating factor (GM-CSF) compared to CMs from normal epithelial cells. Finally, we show that the histamine-containing cell differentiation of HL-60 cells as well as the colony growth induced by EpCM can be fully inhibited by preincubating this CM with a monoclonal neutralizing antibody to human GM-CSF. These studies: (a) illustrate the ability of human upper airway epithelial cells to secrete GM-CSF in vitro; (b) demonstrate differences between normal and inflamed tissue-derived epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of antihistamine (astemizole) and anticholinergic drugs (ipratropium bromide) on bronchoconstriction induced by substance P

Several studies have demonstrated that neuropeptides are present in bronchial tissue. The aim of this study was to evaluate in vivo the influence of antihistamine in comparison to an anticholinergic drug on bronchospasm induced by inhalation of substance P (SP). Seven moderate asthmatic patients (mean age = 34.4 +/- 8.9), five being female, were studied. The acetate salt of SP was prepared in 0.9% saline to produce a dose range of 23 to 184 x 10(-6) mol. Patients were studied on three separate days with an interval of 3 weeks between challenges. On the first day the dose of SP producing a 20% change in FEV1 was calculated from the individual semilogarithmic dose-response curve. On subsequent days, in a randomized double-blind manner, the patients were treated either with astemizole (20 mg BID for three days) and placebo ipratropium bromide or with placebo of astemizole (twice a day for three days) and with pressurized aerosol of ipratropium bromide (IB) (40 micrograms 20 minutes before the challenge). Two way analysis of variance was used for statistical analysis. Our results demonstrated that inhaled SP is able to produce a dose-response curve of bronchoconstriction with a geometric mean of PD20 of 50.51 x 10(-6) moles (37.38 to 68.19 x 10(-6) mol). Treatment with astemizole induced a geometric mean PD20 of 65.51 x 10(-6) mol (33.02 to 130.21 x 10(-6) mol) and the premedication with the IB induced a significant (P less than .05) shift of dose-response curve to SP (geometric mean PD20 = 109.1 x 10(-6) mol; 58.67 to 204.05 x 10(-6) mol). Our results demonstrated that bronchoconstriction induced by SP could be attributed to a weak cholinergic activation and not to histamine release.

Tachyphylaxis to repeated challenges with inhaled adenosine in asthmatic subjects

Adenosine, when administered as an aerosol to asthmatic subjects, provokes a prompt dose-dependent bronchoconstriction. The aim of this study was to establish whether tachyphylaxis in response to repeated inhalations with adenosine occurs in asthmatic subjects. Eight asthmatic patients were studied on three separate days (days A, B, and C) at the same time of day for each subject. Three inhalation tests were performed, separated by one hour, on each study day. The study was conducted in a double-blind fashion and performed in random order. On day A, three adenosine inhalation tests were performed to assess adenosine tachyphylaxis. On day B, a saline inhalation test was carried out between two adenosine challenges to assess the time course of the adenosine tachyphylaxis. On day C, three methacholine inhalation tests were performed to confirm that tachyphylaxis does not occur to methacholine. Repeated inhalation with adenosine, but not methacholine, produced a progressive loss of responsiveness to the nucleoside, which was particularly manifest with the third challenge.

Human lung fibroblast-derived granulocyte-macrophage colony stimulating factor (GM-CSF) mediates eosinophil survival in vitro

Tissue eosinophilia has been reported to occur in pulmonary fibrosis, a disease characterized by chronic inflammation and lung fibroblast proliferation. We have examined the in vitro interaction of these two cell types by determining the in vitro survival of human peripheral blood eosinophils co-cultured with human lung fibroblasts. Survival of eosinophils cultured alone was 10% at day 3 and less than 1% at day 7. In contrast, survival of eosinophils that had been co-cultured with fibroblasts was 98, 90, 73, and 69% at days 3, 7, 10, and 14, respectively. Fibroblast-conditioned medium (CM) elicited a similar result in a dose-dependent fashion. Survival of eosinophils cultured with CM which had been preincubated with a monoclonal-neutralizing antibody to human GM-CSF was inhibited in a dose-dependent manner. Human recombinant-derived GM-CSF supported eosinophil survival in the dose-dependent fashion. Survival at day 7 of eosinophils treated with one single dose of GM-CSF (10 U/ml) was 64%. The effect of fibroblast-CM on eosinophils likely represents true survival since eosinophil proliferation as determined by [3H]thymidine incorporation did not occur. We also report that freshly isolated eosinophils had normal ultrastructural, scanning and transmission electron microscopy characteristics, and were normodense. In contrast, eosinophils co-cultured for 7 days with fibroblasts acquired irregular shapes and became hypodense and partially degranulated. Thus, our results indicate that human lung fibroblast-derived GM-CSF mediates the in vitro survival of human eosinophils.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-induced lung solute clearance in rats is dependent on capsaicin-sensitive nerves

Chemosensitive sensory nerves have an important effector role in the control of vascular permeability in rat airways after neurogenic inflammation. To investigate whether they also have a role in antigen-induced lung inflammation, we have studied the changes in lung solute clearance (LSC) in sensitized rats after aerosol challenge with allergen and the effect of prior capsaicin-induced denervation on these changes. Sprague-Dawley rats were immunized with egg albumin (EA), using aluminum hydroxide and Bordetella pertussis as adjuvants. After 11 days, the animals were challenged for 5 min with aerosolized EA, and the clearance from the lungs of aerosolized 99mTc diethylenetriamine pentaacetic acid (99mTc-DTPA) over 7.5 min (LSC 7.5) was subsequently measured at various times after challenge as an index of epithelial permeability or integrity. Sensitized animals responded to the challenge with immediate respiratory symptoms and with an increased 99mTc-DTPA clearance rate that was detectable at 20 min (mean +/- SE LSC 7.5: baseline, 6 +/- 1%; 20 min, 17 +/- 3%; p less than 0.05), persisted at 4 h (14 +/- 1%; p less than 0.05), and returned to normal values after 24 h. Unsensitized rats exposed to EA and sensitized rats exposed to PBS or to bovine serum albumin did not show any change. Bronchoalveolar lavage failed to show significant changes of cell populations until 24 h, when an increased presence of lymphocytes, PMN, and eosinophils was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Lung permeability in smokers after ambroxol treatment

There is evidence suggesting the involvement of the surfactant system in the development of lung diseases in cigarette smokers. The aim of the present study was to evaluate the effect of Ambroxol on lung epithelial permeability (LEP) in healthy smokers. Ambroxol is known to stimulate surfactant production. Twenty male patients aged between 20 and 60 years participated in the study. They all smoked at least 15 cigarettes daily for 10 years. We carried out a random double-blind study versus placebo: the drug (Ambroxol 75 mg) or the placebo were given once a day after breakfast for 30 days. Lung permeability was evaluated through scanning pulmonary scintigraphy by inhalation of the polydispersed liquid aerosol diethylenetriaminepentaacetic acid (DTPA), labelled with 99Tc, and delivered by a 'Venticis' system. LEP was expressed as the half-time clearance from the lung of 99Tc-DTPA (T50). The significance of the differences between the two treatments was determined by the Student's test for unpaired data. LEP was not different from the baseline value (T50 = 18.49 min) after placebo administration (T50 = 19.57 min). The patients receiving Ambroxol showed an increased LEP mean value (T50 = 18.36 min) in comparison with the baseline mean value (T50 = 16.41 min). Our results demonstrate that the treatment with Ambroxol was able to decrease LEP in 6 subjects, though not significantly.

Effect of an aerosol delivery system on bronchodilator activity

Metered dose inhalers (MDIs) are often used incorrectly by patients who find difficulty using MDI for drug inhalation. The study was performed in 11 asthmatic patients in four days in order to evaluate the efficiency of a new Drug Delivery System (DDS-InspirEase) for metered dose inhalers. Clenbuterol was administered via DDS and via conventional MDI in a randomized manner. On the first two days, DDS and MDI were used by patients without any physician's help. On the subsequent days, clenbuterol was administered via DDS and via conventional MDI directly by the physician. FEV1 and MEF75 values were measured 15', 30', one hour, and two hours post-drug inhalation. Statistical analysis (ANOVA) showed that clenbuterol delivered by DDS, administered by patients or by physician, produced a greater increase in FEV1 values (P less than .05) and MEF75 values (P less than .01) in comparison to the conventional MDI on each test day. No significant differences existed between physician or patient administration of clenbuterol with DDS and MDI. The results showed a greater bronchodilator effect obtained by clenbuterol delivered by DDS.

Inflammatory cells and the epithelium. Mast cell/nerve interactions in the lung in vitro and in vivo

A hypothesis is presented that mast cells in and below the epithelium of the respiratory tract show functional association with nerves to form a homeostatic regulatory unit. During inflammation, mast cells may arise in situ as well as by infiltration because epithelium contains both mast cell precursors and produces factors that support their growth in vitro. Structural studies show that mast cells associate with nerves in the lung. Using a tissue culture model, we showed that sympathetic nerves formed lasting contacts with rat basophilic leukemia (RBL) cells. Electrophysiologic studies showed that nerve contact increases RBL membrane conductance, which can be mimicked by exogenous substance P (SP). Experiments with sensitized rat tracheal mucosa in Ussing chambers showed functional evidence of interaction of mast cells with SP-containing nerves: changes in short circuit current caused by antigen were blocked by the mast cell stabilizer doxantrazole and reduced by 50% by neonatal pretreatment with capsaicin. Experiments in vivo showed that lung clearance of the aerosol probe 99mTc-DTPA was increased by antigen challenge in sensitized rats. This was blocked by neonatal capsaicin treatment, again implicating SP-containing nerves. Therefore, we conclude that the functional association of mast cells with nerves is an important mechanism in regulating the local epithelial environment.

Comparative study of the effects of nedocromil sodium (4 mg) and sodium cromoglycate (10 mg) on adenosine-induced bronchoconstriction in asthmatic subjects

The effect of nedocromil sodium (4 mg; 7.8 X 10(-6) M) on adenosine-induced bronchoconstriction was compared with that of a higher dose of sodium cromoglycate (10 mg; 24.1 X 10(-6) M). Eleven allergic asthmatic patients (mean age 26.28 +/- 12.21 years) were studied. Adenosine (0.03-4.00 mg) was administered as nebulized aerosol. The dose of adenosine producing a 20% change in FEV1(PD20) was calculated from the individual semi-logarithmic dose-response curves. Patients were studied on 4 separate days. On the first day the adenosine challenge was performed; on subsequent days patients were pretreated (20 min before challenge) with either placebo or test drug (nedocromil sodium 2 x 2 mg or sodium cromoglycate 2 x 5 mg) administered by pressurized aerosol in a randomized, double-blind manner. Statistical analysis was performed by two-way analysis of variance. Neither sodium cromoglycate nor nedocromil sodium showed a significant bronchodilator effect. In patients treated with placebo, inhalation of adenosine produced a dose-related bronchoconstriction with a geometric mean PD20 of 0.42 mg. After drug administration the mean PD20 values were 1.29 mg with sodium cromoglycate and 2.30 mg with nedocromil sodium. Both drugs produced a significant increase in mean PD20 value in comparison with placebo and baseline (P less than 0.01). These results demonstrate that nedocromil sodium (4 mg) is significantly more potent than a larger dose of sodium cromoglycate (10 mg) in inhibiting adenosine-induced bronchoconstriction (P less than 0.05).

Effect of nedocromil on bronchospasm induced by inhalation of substance P in asthmatic subjects

Several studies have demonstrated that neuropeptides are present in peptidergic fibres of bronchial tissue. The aim of the present study was to evaluate in vivo the effect of nedocromil sodium (2 x 2 mg) on bronchospasm induced by inhalation of substance P. Six moderate asthmatic patients, mean age 25.17 years, were studied. Airway response was measured as FEV1 and the dose of substance P (using a dose range of 23-736 nmol) producing a 20% decrease in FEV1 (PD20) was calculated from the individual semilogarithmic dose-response curves. Patients were studied on 3 separate days in a randomized, double-blind manner. On the first day a baseline PD20 value was determined. On subsequent days substance P challenge was performed after pretreatment (20 min before challenge) with either placebo or nedocromil sodium. Student's paired t-test and Wilcoxon's test were used for statistical analysis. The results of this study demonstrated that inhalation of substance P causes a dose-dependent bronchoconstriction and that the bronchoconstriction induced by substance P can be prevented by pre-treatment with nedocromil sodium.

Enhancing effect of dipyridamole inhalation on adenosine-induced bronchospasm in asthmatic patients

The study was performed on 13 asthmatic patients to determine whether inhaled dipyridamole would act directly by inducing bronchoconstriction or indirectly by potentiating the adenosine-induced bronchoconstriction. The study was performed in 3 consecutive days. On the first day adenosine challenge was performed and the PD20 value calculated. On the other days the adenosine challenge was done 5 min after randomized inhalations of dipyridamole or a control solution. The mean percent change in FEV1 after dipyridamole (delta % = 2.0) and control solution (delta % = 1.0) was not significant. Inhaled adenosine caused bronchoconstriction with a geometric mean PD20 of 1.09 mg. After control solution inhalation, a mean PD20 value of 1.31 mg was observed. Dipyridamole inhalation increased adenosine hyperresponsiveness and in all subjects shifted the dose-response curves of adenosine challenge to the left with a mean PD20 value of 0.40 mg. This enhancing effect of dipyridamole was significant when compared with the baseline value (P less than 0.01) and control solution (P less than 0.01). The study demonstrated that dipyridamole inhalation increased airway responsiveness to adenosine in all subjects. This effect is due to indirect activity of dipyridamole on airways without changes in baseline airway caliber.

Bronchospasm induced by inhalation of substance P: effect of sodium cromoglycate

The aim of this study was to evaluate in vivo the effect of inhaled substance P (SP) and to determine the effect of sodium cromoglycate (SCG) on bronchospasm induced by its inhalation in 6 asthmatic patients. At the beginning of the study, all patients were asymptomatic, with an FEV1 value not less than 20%. SP was administered as aerosol, prepared in 0.9% saline to produce a dose range of 0.03-1 mg. Airway response was measured as FEV1 using a pulmonary system 47120A Hewlett-Packard instrument. The dose of SP producing a 20% change in FEV1 was calculated from the individual semi-logarithmic dose-response curve (PD20). After administration of the placebo, SP produced a dose-related bronchoconstriction with a geometric mean PD20 of 0.15 mg. After SCG, the mean PD20 value was of 0.64 mg (p less than 0.01). These results confirmed the bronchospasm induced by inhalation of SP and demonstrated that SCG is able to prevent this effect although it is impossible to define the exact mechanism of the drug.

Effect of sodium cromoglycate and nifedipine on adenosine-induced bronchoconstriction

Inhaled adenosine causes bronchoconstriction in asthmatic patients. In 7 symptom-free asthmatics a study was performed to investigate the effect of sodium cromoglycate and nifedipine on adenosine-induced bronchoconstriction. All patients were challenged with increasing doses (from 0.03 to 2 mg) of nebulized adenosine to assess airway reactivity. The same procedure was repeated on different days at the same time each morning after administration of placebo and drugs in a randomized double-blind study. Airway response was measured as the forced expiratory volume in 1 s (FEV1). The PD20 value and the fall of FEV1 at the provocative dose were calculated. The PD20 data were modified in log values and the statistical analysis was performed by two-way analysis of variance. Mean decrease of FEV1 after adenosine challenge was 26.02 and 28.87% with placebo sodium cromoglycate and placebo nifedipine, respectively. Sodium cromoglycate and nifedipine gave a mean decrease of FEV1 of 6.44% (p less than 0.05) and 22.22%, respectively. PD20 values (geometric mean) after adenosine inhalation were 0.72 and 0.74 mg for placebo sodium cromoglycate and placebo nifedipine and 0.86 mg for nifedipine. Sodium cromoglycate gave a significant protection against adenosine in all subjects and in no case did the maximum dose used (2 mg) result in a fall in FEV1 value greater than 20%. Adenosine antagonism could be considered as a possible factor contributing to the pharmacologic efficacy of sodium cromoglycate in asthmatic patients. No protective effect was noticed with nifedipine.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchodilator effect of Aerochamber and Inspirease in comparison with metered dose inhaler

This trial was performed in a randomized double-blind manner on four different days in 13 asthmatic patients in order to compare the bronchodilator efficacy of two different inhalation devices, Inspirease (IP) and Aerochamber (AC), to the conventional metered dose inhaler (MDI). The results showed that clenbuterol determined a significant FEV1 increase inhaled either via MDI or via IP and AC. IP caused a greater bronchodilatation than AC, 30 min after clenbuterol administration. IP caused a greater mean increase (P less than 0.05) in FEV1 than the MDI at all time intervals; AC provided an improvement in bronchodilator response over directly administered MDI. Such responses are only marginally clinically relevant when patients use MDI correctly. These devices are mainly indicated in patients with poor hand-lung coordination.

Relationship of serum theophylline concentrations to histamine-induced bronchospasm

This study was performed in a randomized double-blind manner on 6 separate days in 10 asthmatic patients to investigate the effect of a sustained theophylline on baseline bronchial hyperreactivity to histamine in relation to the theophylline serum levels and the degree of bronchodilatation produced. No significant bronchodilatation was seen after theophylline administration at every time of evaluation. An improvement of PD20 values of histamine was observed after 4 h (p less than 0.05), 8 h (p less than 0.01) and 12 h (p less than 0.05) from theophylline administration versus respective PD20 values obtained with placebo at the same times. No significant correlation was found between serum theophylline levels and percentage change of PD20 values after drug administration (r = 0.250). We observed an improvement of PD20 mean values in relation to the maximal serum theophylline concentration but our study failed to correlate the degree of protection with serum concentration.

Effect of nifedipine on allergen-induced bronchoconstriction

The effect of nifedipine on allergen-induced asthma in nine asthmatic subjects was studied. All subjects had a history of asthma and positive Prick test; lyophilized allergen extracts of Dermatophagoides Pteronyssinus were used. All solutions were inhaled through DeVilbiss nebulizer. On the first day baseline FEV1 value was measured, allergen extracts were inhaled at increasing doses. The procedure was repeated until a 20% fall from the baseline FEV1 was obtained. Nifedipine or placebo capsules were administered sublingually in a randomized double blind manner. Antigen challenge was given 30 minutes later by using provocating dose of allergen. The change in FEV1 value was calculated from the post nifedipine administration. A significant negative correlation (p less than 0.01) was found between the percentage of protection and the baseline PD20. Nifedipine produced a significant mean change of the bronchial reactivity threshold (p less than 0.01).

Effect of Duovent (ipratropium bromide and fenoterol) on non-specific bronchial hyperreactivity

Beta 2-adrenergic and anticholinergic drugs have shown an action in modulating bronchial hyperreactivity to various stimuli (chemical, physical, immunological, pharmacological). The aim of our study was to compare the efficacy of a combination of ipratropium bromide and fenoterol (Duovent) with the activity of single drugs in the prevention of histamine-induced bronchospasm. Twenty-six atopic asthmatic subjects were examined in a double-blind trial, during an asymptomatic period, with a FEV1 value not lower than 20% of the predicted normal value. During 4 consecutive days all patients received 2 puffs, respectively, of Duovent (200 micrograms fenoterol + 40 micrograms ipratropium bromide), fenoterol (400 micrograms), ipratropium bromide (80 micrograms) and placebo in a randomized order. PD20 values were evaluated after each drug administration: after 2 h in 16 patients and after 5 h in the other 10 patients. The data were modified to log values, and statistical analysis was performed by two-way analysis of variance. This study showed that Duovent and fenoterol have a protective effect against histamine-induced bronchospasm with a significant increase in the PD20 values 2 h (p less than 0.01) and 5 h (p less than 0.05) after treatment when compared to placebo. Duovent inhalation determined a more protective effect than other drugs but not significantly when compared to fenoterol. Some advantages in the modulation of bronchial reactivity could be seen from using Duovent because with the lower dose of the beta 2-adrenergic drug the same results could be obtained without side-effects.