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Biomedical subjects

V Bellia

Publications and source records attributed to V Bellia.

At least 19 recordsLinked to original sources
PubMed1996

Urinary leukotriene E4 in the assessment of nocturnal asthma.

BACKGROUND: Urinary leukotriene E4 (LTE4) is a marker of the body's production of cysteinyl LTs, important mediators of airway inflammation. The role of the latter in nocturnal asthma is a topic of increasing interest. OBJECTIVE: This investigation was aimed at determining whether nighttime attacks are associated with increased release of LTs, expressed by urinary LTE4, and the relationship between the two phenomena. METHODS: Three groups were studied: group A, seven control subjects; group B, nine asthmatic patients without nocturnal attacks; and group C, nine asthmatic patients with a comparable daytime FEV1 but who were experiencing nocturnal exacerbations (morning dips in peak expiratory flow greater than 20%). Urine was collected over 24 hours in three samples (9:00 AM to 3:00 PM; 3:00 PM to 9:00 PM; and 9:00 PM to 9:00 AM). LTE4 was measured by high-performance liquid chromatography and radioimmunoassay and expressed as nanograms per millimole of creatinine. RESULTS: No significant differences between urinary LTE4 were noticed within groups A and B. Conversely, in group C urinary LTE4 at night (geometric mean with 95% confidence interval; 35.16 with 28.77-42.85) was significantly higher than that of the other samples (respectively 23.12 with 17.78-30.06, p less than 0.05; and 25.18 with 21.03-30.13, p less than 0.02); it was also significantly higher than in all the samples of other groups. A significant (p less than 0.02) linear correlation was observed between morning dip in peak expiratory flow and the log urinary LTE4 in the nocturnal sample. CONCLUSION: These results indicate the role of LTs in nocturnal asthma and suggest that urinary LTE4 may be a useful marker of this condition.

Activity Cycles↗
PubMed1995

[Respiratory medicine in geriatrics. A cultural niche of relevant theoretical and practical importance].

Respiratory medicine in the elderly represents a topic of increasing interest in the developed countries, because of its peculiar clinical and therapeutical implications. In this respect, a deeper knowledge of the biology and physiology of aging lung is desirable: namely, the age-related immunological and structural changes involving the respiratory system do influence clinical presentation and response to the treatment in older people. A better understanding of the pharmacology in the elderly which is recognized to be different for several aspects from that of the general population, is mandatory in order to better approach these practical problems. This short review emphasizes the need of the "longitudinal", rather than "transversal", epidemiological surveys which are uniquely able to give useful information on the natural history, even in older populations. In addition, clinical and therapeutical peculiarities of some respiratory illnesses such as infectious lung diseases, including pulmonary tuberculosis, COLD and bronchial asthma, sleep-related respiratory disorders will be underlined. Finally, a few problems concerning the management of the geriatric subject with chronic respiratory disease will be analyzed, focusing mainly on the difficulties inherent in the inhalant therapy and functional evaluation of this kind of patients.

Aged↗
PubMed1994

Ventilatory response to spontaneous resistive load variations during sleep.

We investigated the ventilatory response to spontaneous changes in resistive load during sleep in nine adult asthmatic patients, four of whom were snorers. All patients had a history of nocturnal worsening of respiratory symptoms and were submitted to a nocturnal polysomnographic study in a sleep laboratory. During the night, all patients showed spontaneous increases in pulmonary resistance due to bronchoconstriction. A temporary additional increase in inspiratory resistance (RI) was observed as a result of snoring. In all patients, a highly significant inverse linear relationship was found between ventilation (VE) and RI, but the slopes of the regressions varied considerably among patients; the decrease in VE was due to a reduced mean inspiratory flow. The most effective ventilatory compensation to increasing resistive load (lowest absolute values in the VE/RI slopes) was observed in two patients: one nonsnorer and one snorer. Effective VE compensation appeared to be dependent on the individual's combined adjustments of transpulmonary pressure (Ptp) and duty cycle (TI/TT). In fact, an increase in Ptp, linearly related to RI, was observed in all patients except one (a snorer during nonsnoring breathing); however, the Ptp increase was able to compensate VE only when TI/TT increased. We conclude that, in sleeping asthmatic patients, VE adaptation to increased spontaneous load is highly variable among patients and its effectiveness is related to individual strategies on the basis of adequate adjustments of neuromuscular output and timing of the breathing cycle.

Adult↗
PubMed1994

Theophylline suppresses the release of tumour necrosis factor-alpha by blood monocytes and alveolar macrophages.

The purpose of this study was to evaluate the effect of theophylline on tumour necrosis factor-alpha (TNF-alpha) release by human blood monocytes (BMo), and rat BMo and alveolar macrophages (AM). BMo and AM were incubated in the absence or presence of theophylline, and the cell-free supernatants were harvested and tested for TNF-alpha activity by bioassay. Theophylline dose-dependently reduced TNF-alpha release by human BMo: significant inhibition was observed at 100 microns (41 +/- 5.9% of controls) and at 50 microns (59 +/- 4.8% of controls), while the inhibitory activity of theophylline at 10 microns (71 +/- 8.9% of controls) was not statistically significant. This activity was maximal at 2 h and declined at 4 h (59 +/- 5.2% of controls) and 24 h (89 +/- 3.1% of controls). Northern analysis performed on ribonucleic acid (RNA) extracted from human BMo demonstrated that theophylline was able to reduce TNF-alpha gene expression. Comparable levels of inhibition of TNF-alpha release were observed on rat BMo and AM (rat BMo 42 +/- 4.9% of controls; rat AM 38 +/- 1.7% of controls), suggesting that BMo and AM are equally susceptible to suppression of TNF-alpha release induced by theophylline. These results indicate that theophylline suppresses TNF-alpha release by mononuclear phagocytes. Since TNF-alpha is involved in the pathogenesis of bronchial hyperresponsiveness and asthma, our results suggest that the therapeutic activity of theophylline might be partly related to its effect on TNF-alpha release.

Animals↗
PubMed1993

Thyroarytenoid muscle activity in sleep apneas.

In normal subjects the thyroarytenoid muscle (TA), a vocal cord adductor, has phasic expiratory activity during wakefulness that disappears during non-rapid-eye-movement (NREM) sleep. Fiber-optic studies have reported absent or irregular vocal cord movements during obstructive apneas and vocal cord adduction during central apneas. This study was designed to investigate TA activity during NREM sleep in 14 subjects with sleep apnea by means of intramuscular wire electrodes. During central apneas, which were recorded in three subjects, continuous TA activity was observed. During obstructive apneas, which were recorded in all subjects, two different patterns of TA activity were observed: 1) absence of any activity until arousal and 2) phasic activity throughout the apnea. The first pattern was detected in six subjects, whereas both patterns were observed in the remaining eight subjects. No correlation was found between obstructive apnea characteristics and presence or absence of TA activity. In all subjects TA underwent a marked activation during arousal. While nasal continuous positive airway pressure was applied during NREM sleep TA activity was always absent. The persistence of TA activity during central apneas suggests that they may represent an extreme prolongation of neural expiratory discharge. We speculate that a variable interaction of different stimuli acting during obstructive apnea may activate TA, which, in turn, may contribute to glottic narrowing.

Adult↗
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

Thyroarytenoid muscle activity during loaded and nonloaded breathing in adult humans.

Previous fiber-optic studies in humans have demonstrated narrowing of the glottic aperture in expiration during application of expiratory resistive loads. Nine healthy subjects were studied to determine the effect of expiratory resistive loads on the electromyographic activity of the thyroarytenoid (TA) muscle, a vocal cord adductor. Four of the nine subjects also underwent the application of inspiratory resistive loads and voluntary prolongation of either inspiratory (TI) or expiratory (TE) time. TA activity was recorded by intramuscular hooked-wire electrodes. During quiet breathing in all subjects, the TA was phasically active on expiration and often tonically active throughout the respiratory cycle. TA expiratory activity progressively increased with increasing levels of expiratory load. Inspiratory loads resulted in increased TA "inspiratory" activity. Voluntary prolongation of TE to times similar to those reached during loaded breathing induced increases in TA expiratory activity similar to those reached during the loaded state. Voluntary prolongation of TI was associated with an increase in TA inspiratory activity. Similar increases in TI during inspiratory loading or voluntary conditions were associated with comparable increases in TA inspiratory activity in three of the four subjects. In conclusion, increased activation of TA during the application of expiratory resistive loads implies that the reported narrowing of glottic aperture during expiratory loading is an active phenomenon. Changes in activation of the TA with resistive loads appear to be related to changes in respiratory pattern.

Adult↗
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

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↗