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Biomedical subjects

G Bonsignore

Publications and source records attributed to G Bonsignore.

At least 19 recordsLinked to original sources
PubMed1992

Acute effects of oxygen administration on transmural pulmonary artery pressure in obstructive sleep apnea.

In order to investigate the role of hypoxia on the cyclic oscillation of transmural pulmonary artery pressure (PAP) in obstructive sleep apnea, oxygen was administered during one half of the night to six patients affected by obstructive sleep apnea syndrome during a nocturnal polysomnographic study. In each patient, transmural PAP measurements were performed on 15 randomly selected apneas recorded while breathing room air, and on 15 during O2 administration. During O2 administration in all patients, apneas were associated with a higher oxyhemoglobin saturation (SaO2), a smaller SaO2 swing, and a higher transcutaneous PCO2. The mean highest level of transmural PAP in the apneic episodes, commonly reached at their end, was significantly lower than while breathing room air in only two patients; however, due to a decrease in the mean lowest PAP level (at the beginning of apneas), the extent of the PAP increase within apneas did not differ between air and O2 breathing; these patients showed the smallest increase in transcutaneous PCO2 in our sample. End-apneic transmural PAP during O2 administration was significantly higher in one subject (for systolic values) and was not significantly different in the remaining three subjects. The extent of the increase in transmural PAP within apneas was greater in one patient; it was smaller in another one, but only for the diastolic values; and it did not differ significantly with respect to the value observed while breathing room air in all of the other subjects. The results suggest that hypoxia in obstructive apneas, at least in some patients, may lead to a steady increase in PAP, detectable both at the beginning and at the end of the episodes; conversely, the increase in PAP within apneas does not seem to be influenced by the simultaneous decrease in SaO2.

Air↗
PubMed1991

Occurrence of breathing disorders during CPAP administration in obstructive sleep apnoea syndrome.

The spectrum of breathing events during sleep in patients with obstructive sleep apnoea syndrome (OSAS) after the abolition of obstructive apnoeas has been extensively studied in tracheostomized patients, but has received much less attention in patients submitted to continuous positive airway pressure (CPAP). We analysed the breathing pattern during sleep in forty patients while CPAP was administered. A regular breathing pattern throughout the sleep study was observed in 15 patients. In the remaining 25 subjects, one or more of the following events was observed: central apnoeas, hypopnoeas, periodic breathing, prolonged oxyhaemoglobin desaturations. Central apnoeas during non-rapid eye movement (NREM) sleep appeared almost exclusively after arousals or wakefulness periods; their prevalence did not significantly differ between subjects who showed and who did not show similar events before CPAP. Central apnoeas in rapid eye movement (REM) sleep had a random occurrence. Hypopnoeas were found only in REM sleep, and, like central apnoeas, occurred randomly; in one patient they had a prolonged duration (up to 110 s). Periodic breathing was observed in only two subjects, one of whom had congestive heart failure: it was limited to NREM sleep and was not associated with arousals or shifts in sleep stage. Prolonged oxyhaemoglobin desaturations were found mainly in REM sleep; most subjects with such abnormalities had daytime blood gas alterations. In conclusion, abnormalities of the breathing pattern of patients with OSAS can be observed during CPAP and after tracheostomy, but periodic breathing is less common than is reported after tracheostomy, and is probably caused by different mechanisms.

Female↗
PubMed1990

Expiratory timing in obstructive sleep apnoeas.

Diaphragmatic electromyogram was recorded during NREM sleep in 4 patients affected by obstructive sleep apnoea (OSA) syndrome in order to evaluate the behaviour of expiratory time (TE) in the course of the obstructive apnoea-ventilation cycle. The two components of TE, i.e. time of post-inspiratory inspiratory activity (TPIIA) and time of expiratory phase 2 (TE2) were separately analysed. TPIIA showed a short duration, with only minor variations, within the apnoea, while its duration was more variable and longer in the interapnoeic periods: the longest TPIIA values were associated with the highest inspiratory volumes in the same breaths. This behaviour seemed regulated according to the need of a more or less effective expiratory flow braking, probably as a result of pulmonary stretch receptors discharge. Conversely TE2 showed a continuous gradual modulation, progressively increasing in the pre-apnoeic period, decreasing during the apnoea and increasing in the post-apnoeic period: these TE2 variations seemed related to oscillations in chemical drive. These data show that TE in the obstructive apnoea-ventilation cycle results from a different modulation in its two components and suggest that both mechanical and chemical influences play a role in its overall duration.

Adult↗
PubMed1989

[Cefotetan in the therapy of respiratory infections. Multicenter research].

In a controlled multicenter trial 291 patients have been treated with cefotetan. They suffered from acute or chronic exacerbated bronchopulmonary disorders. In 110 patients it was possible to identify the etiological agent: enterobacteria (62), non-fermentative gram-negative bacilli (10), Haemophilus influenzae (8), Branhamella catarrhalis (1), Streptococcus pneumoniae (19), Staphylococcus aureus (12), Streptococcus pyogenes (4). In the exacerbations of chronic bronchitis (203), cefotetan was generally administered at the dose of 1 g/12 h i.m., whereas it was administered at the dose of 2 g/12 h i.v. in acute infection. The mean duration of therapy was 8.8 days. Positive clinical results were obtained in 251 patients (86.2%) with eradication of the pathogen initially isolated in 90.5% of cases. Cefotetan showed good local and general tolerance. The results obtained confirm those of studies concerning limited numbers of patients and show the efficacy of cefotetan both in acute and chronic pathologies, also in patients with serious involvement of their general conditions (concomitant pathologies, high mean age).

Acute Disease↗
PubMed1989

Relationship of nocturnal bronchoconstriction to sleep stages.

The possible role of sleep stages in the pathogenesis of nocturnal asthmatic attacks is still under debate because previous studies suffered methodologic limitations that prevented the possibility of providing a clear-cut answer to the question. To evaluate the relationship of nocturnal asthma to sleep, eight asthmatics with unstable asthma (seven with history of nocturnal wheeze) and four reference subjects were submitted to all-night polysomnography, including the continuous evaluation of esophageal and supraglottic pressure (with two catheters) as well as of airflow (with a face mask), so as to derive total lung resistance, supraglottic resistance, and, by subtraction lower respiratory resistance (Rlr). Stage 3-4 was characterized by the highest peaks in Rlr and by longer episodes of bronchoconstriction; conversely, neither the onset nor the remission of the latter were specifically related to any sleep stage. Considering episodes remitted with an awakening. Stage 3-4 was marked by higher Rlr peaks than during REM sleep. We conclude that sleep plays a contributory role in the multifactorial pathogenesis of nocturnal asthma, with a higher susceptibility during slow-wave sleep, probably related to a decreased responsivity to resistive loads.

Adult↗
PubMed1989

Transmural pressure measurements. Importance in the assessment of pulmonary hypertension in obstructive sleep apneas.

Seven patients with OSAS were studied during nocturnal sleep in order to assess the trend of PAP throughout apneas and to identify factors possibly associated with such a trend. All patients underwent a polysomnography including the monitoring of PAP and esophageal pressure. While intravascular PAP decreased during apneas and increased at the resumption of breathing, transmural PAP values (ie, corrected for intrathoracic pressure swings) showed a trend toward a progressive increase throughout apneas and toward a decrease once ventilation had been resumed. The measurement of transmural values allowed a reliable assessment of PAP changes occurring during apneas, and different degrees of such changes shown by different patients may be related to a host of factors relevant to wakefulness and sleep, including individual responsivity to hypoxic stimulus.

Adult↗
PubMed1989

Lung compartmentalization of increased TNF releasing ability by mononuclear phagocytes in pulmonary sarcoidosis.

The TNF is a monokine with cytotoxic and tumor-necrosing activities; in addition, TNF may play a role in inflammatory processes. The present study evaluates spontaneous and LPS-mediated release of TNF by AMs and autologous peripheral BMs of normal subjects and patients with pulmonary sarcoidosis. A recently developed cytotoxicity assay, specific for detection of TNF activity, was applied. This study demonstrates that (1) unstimulated mononuclear phagocytes released low levels of TNF with no differences between groups; (2) when effector cells were stimulated with LPS, AMs from patients with active pulmonary sarcoidosis released more TNF than AMs recovered from normal subjects and from patients with inactive disease; (3) this increase was compartmentalized to the lungs, since comparisons of TNF production by LPS-stimulated BMs failed to show any difference between study groups. These results suggest that TNF might play a role in the pathogenesis of the alveolitis of pulmonary sarcoidosis.

Adult↗
PubMed1989

Peak flow records in asthma: evaluation of an algorithm for interpretation of patterns.

The clinical value of serial measurements of peak expiratory flow (PEF) in asthma is well established, but the analysis of the PEF records is not standardized. We developed an algorithm for interpretation of PEF, based upon the characteristic features of chronic airflow limitation, and retrospectively analysed the PEF of fifty outpatients affected by non-seasonal asthma. For each patient we correlated the developed indices of evolution of PEF with, respectively, the severity of asthma (evaluated in terms of consumption of drugs), forced expiratory volume in one second and with the trend of the indices over several months. The developed indices were well correlated with the severity score and to a lesser extent to other investigated parameters. These results seem to provide a useful approach to a computerized evaluation of the results of PEF monitoring.

Adolescent↗
PubMed1988

Tumor necrosis factor release by pulmonary alveolar macrophages.

Tumor necrosis factor (TNF) is a monokine with cytotoxic and tumor-necrosing activities that may play a role in host defence against malignancies. The aim of the present study was to assess the ability of pulmonary alveolar macrophages (AMs) to release TNF. To accomplish this, a cytotoxicity assay specific for TNF detection was applied, using as targets actinomycin-D-pretreated WEHI 164 murine sarcoma cells. AMs mediated cytotoxicity levels comparable to those mediated by autologous blood monocytes (BMs). In addition, cytotoxicity was accounted for by a soluble factor released by effector cells and was completely inhibited by the addition of anti-TNF antibodies. These results indicate that AMs are able to release TNF. Moreover, since TNF has now been recognized as an important mediator of inflammation, its production by AMs suggests that this monokine might play a role in the pathogenesis of a variety of nonmalignant lung disorders.

Adult↗
PubMed1988

Validation of morning dip of peak expiratory flow as an indicator of the severity of nocturnal asthma.

Overnight falls in peak expiratory flow (PEF) (with the morning dip of the index) may be considered the hallmark of nocturnal asthma. To validate the morning dip a quantitative marker of the degree of nocturnal bronchoconstriction, the dip was measured in 11 subjects (six with a history consistent with nocturnal asthma) undergoing all-night monitoring of lower respiratory resistance by a double-catheter method. In six subjects, marked and recurrent increases in resistance were recorded, along with morning dips higher than 20 percent; however, on the following morning, only two of them reported having suffered significant breathlessness and wheeze. Peak and average values for resistance, as well as the duration for which resistance was increased, were closely correlated with the magnitude of morning dips. Therefore, unlike the subjective report, PEF may be considered a reliable quantitative indicator of nocturnal bronchoconstriction.

Adult↗
PubMed1988

Effects of oral steroids on immunoglobulins in bronchoalveolar lavage fluid in active sarcoidosis.

Immunoglobulin (Ig) levels increase in the lower respiratory tract of patients with pulmonary sarcoidosis. We evaluated the effects of prednisone therapy upon Ig concentrations in bronchoalveolar lavage (BAL) fluid of ten patients with active disease (greater than 30% T-lymphocytes in BAL and positive 67Gallium (67Ga) lung scan). Therapy significantly lowered T-lymphocyte percentages in BAL and 67Ga lung scan indices and was followed by a slight improvement of the studied functional parameters. Biochemical analysis of BAL showed a significant decrease of both IgG/albumin (baseline 1.24 +/- 0.21; after therapy 0.40 +/- 0.12) and IgA/albumin (baseline 0.55 +/- 0.07; after therapy 0.14 +/- 0.03) ratios in all patients. Conversely, comparisons of IgM/albumin ratios did not show any change over the study period (baseline 0.05 +/- 0.01; after therapy 0.06 +/- 0.03). Thus oral steroid treatment suppresses the alveolitis of pulmonary sarcoidosis, as shown not only by the reduction of lung T-cells and 67Ga lung uptake, but also by the decreased Ig levels in the alveolar spaces.

Adult↗
PubMed1987

Continuous positive airway pressure improves the quality of sleep and oxygenation in obstructive sleep apnea syndrome.

We tested the effects of continuous positive airway pressure (CPAP) in 8 patients with obstructive sleep apnea syndrome (OSAS). The comparison of a nocturnal polygraphic study performed during spontaneous breathing with a study during CPAP administration performed the following night showed a significant reduction in stage 1 and increase in REM, the abolition of obstructive apneas and a significant increase in mean oxyhemoglobin saturation. Most patients reported marked relief of symptoms after the first night of treatment. However 3 patients, though confirming the improvement refused further CPAP. We conclude that CPAP is an effective measure for prevention of apneas in OSAS and that in compliant patients it may be regarded as a short-term measure when a permanent correction of the causes is planned, or as a long-term treatment when the latter is not feasible.

Aged↗
PubMed1987

Ambroxol for the prevention of chronic bronchitis exacerbations: long-term multicenter trial. Protective effect of ambroxol against winter semester exacerbations: a double-blind study versus placebo.

In a 6-month, double-blind multicenter trial conducted over the winter, the effects of daily administration of ambroxol retard (75 mg) were compared with those of placebo in preventing exacerbations and improving symptoms and clinical signs in chronic bronchitis patients. The trial was completed by 110 patients in the ambroxol group and by 104 in the placebo group. Initially, there were no significant differences between the groups. By the end of the 2nd month of treatment, 67.2% of the ambroxol group had had no exacerbations compared to 50.4% in the placebo group. At the end of the 6-month trial, 45.5% of the treatment group had had no exacerbations, compared to only 14.4% of the control group. These differences were statistically significant. Patients in the treatment group lost significantly fewer days through illness (442) and had fewer days when they needed antibiotic therapy (371) compared to the placebo group patients (837 and 781). Ambroxol also produced statistically significant symptomatic improvement, measured as difficulty in expectoration, coughing, presence of dyspnea and the auscultatory signs as compared to controls. Since ambroxol was well tolerated and compliance was good, it appears like a drug of choice for pharmacological prophylaxis of chronic bronchitis.

Adult↗
PubMed1986

The combination of fenoterol and ipratropium bromide in bronchial asthma: comparison of the acute effects of two different dosages.

Combinations of beta-stimulant and anticholinergic drugs have been advocated as a potentially useful tool in the treatment of reversible airway obstruction. We investigated the effectiveness and safety of a metered aerosol preparation delivering fenoterol 100 micrograms and ipratropium bromide 40 micrograms per puff: two dosages (2 puffs and 4 puffs) were used in 16 asthmatic patients, and their acute effects (up to 420 min) were investigated in a double-blind randomized trial. The results point out a reasonably good response to both dosages, with no notable difference between them as far as vital capacity, FEV 1, MMEF and Vmax75 are concerned. This finding indicates the possibility of achieving a satisfactory bronchodilation at beta-stimulant dosages far lower than the standard ones commonly used and therefore minimizing the risk of untoward cardiovascular effects.

Asthma↗