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Biomedical subjects

M Dottorini

Publications and source records attributed to M Dottorini.

At least 19 recordsLinked to original sources
PubMed2000

Myasthenic inspiratory vocal cord dysfunction: efficacy of nasal continuous positive airway pressure treatment.

Myasthenic vocal cord dysfunction (VCD), presenting with severe inspiratory stridor, was successfully treated with nasal continuous positive airway pressure (nCPAP), thus giving the medical staff time to make the diagnosis and avoiding intubation or tracheostomy. An important sign leading to diagnosis was the very high MEF(50)/MIF(50) ratio calculated from the flow-volume loop. nCPAP treatment induced prompt remission of stridor and a sharp reduction in the MEF(50)/MIF(50) ratio from 9.90 to 1.36. A review of the literature has shown that VCD with inspiratory stridor is an unusual onset symptom of myasthenia gravis and that nCPAP treatment may avoid emergency oral/tracheal intubation and tracheostomy. After diagnosis, the patient underwent thymectomy, and today, 3 years later, he is well without any further therapy.

Adult↗
PubMed1997

Prolonged ECG abnormalities in a subject with high altitude pulmonary edema (HAPE).

High Altitude Pulmonary Edema (HAPE) is an uncommon type of non-cardiogenic pulmonary edema. Few data are available regarding ECG abnormalities in patients with HAPE. They are usually slight and related to acute pulmonary hypertension. This paper describes a case of prolonged ECG abnormalities in a subject with HAPE, with no proven cardiac diseases. The Authors discuss the pathopysiological aspects of this kind of hypoxic-induced right ventricular overload with extensive T-wave negativity in precordial leads.

Adult↗
PubMed1996

Nasal-continuous positive airway pressure in the treatment of near-drowning in freshwater.

In patients who have experienced near-drowning, hypoxemia is the major clinical consequence. We report two cases of patients who have experienced near-drowning in freshwater who were successfully treated with nasal-continuous positive airway pressure (N-CPAP) plus oxygen therapy. Both patients presented a radiographic appearance of bilateral pulmonary edema. We suggest the use of N-CPAP as an easier and less costly alternative to tracheal intubation for treating near-drowning in patients who are breathing spontaneously and who have not experienced loss of consciousness.

Adolescent↗
PubMed1994

Encapsulation of Cryptococcus neoformans regulates fungicidal activity and the antigen presentation process in human alveolar macrophages.

Our previous studies have shown that unstimulated alveolar macrophages (AM) play a predominant role as antigen-presenting cells in Cryptococcus neoformans infections, while the function as effector cells seems to be of minor relevance. The present study focuses on the role of encapsulation of C. neoformans on fungicidal activity and the antigen presentation process of AM. Fungicidal activity in unstimulated AM occurs to a higher degree when the acapsular strain is employed, but this is impaired compared with other natural effectors, such as peripheral blood monocytes (PBM) and polymorphonuclear (PMN) cells. Cryptococcus-laden AM also induce a higher proliferative response in autologous CD4+ lymphocytes when the acapsular strain is used compared with encapsulated yeast. The enhanced blastogenic response is, in part, ascribed to an augmented IL-2 production by T cells. In addition, higher levels of interferon-gamma (IFN-gamma), but not IL-4, are produced by the responding T cells, when the acapsular strain is used compared with the encapsulated yeast. Moreover, IFN-gamma is able to induce fungicidal activity in AM against the encapsulated yeast and augments killing activity of the acapsular strain. This phenomenon is not mediated by nitric oxide production, but is correlated with an enhancement of fungicidal activity of cytoplasmic cationic proteases. We speculate that encapsulation of C. neoformans could down-regulate the development of the immune response mediated by Cryptococcus-laden AM at lung level.

Adult↗
PubMed1994

Role of human alveolar macrophages as antigen-presenting cells in Cryptococcus neoformans infection.

The contribution of human alveolar macrophages (AM) from normal subjects in Cryptococcus neoformans infection was investigated. AM were able to efficiently phagocytize the fungus after opsonization, but killing activity did not occur at an effector-to-target ratio of 10:1 in a 6-h incubation since there was an inhibition of phagosome-lysosome fusion. Moreover, the role of AM as antigen-presenting cells was investigated. Cryptococcus-laden AM were co-cultured with autologous T lymphocytes and lymphoproliferation was determined; a massive blastogenic response of alpha/beta TCR-bearing T lymphocytes was observed. The response started after 1 day of co-culture and was triggered and regulated by IL-1 produced by AM in response to C. neoformans. Finally, the antigen-presentation process was associated with HLA class II DR molecules. This finding suggests that AM play a key role in the lung as antigen-presenting cells and, through the secretion of IL-1, regulate proliferation and activation of T lymphocytes, which are important in mediating pulmonary clearance. We speculate that in immunodepressive conditions, the impairment of AM functions could contribute to the spread of C. neoformans infection from the lung.

Adult↗
PubMed1994

Macrophage activation by N-acetyl-cysteine in COPD patients.

The effect of in vivo and in vitro N-acetylcysteine (NAC) treatment on destructive activity of macrophages against Candida from COPD patients has been evaluated. Patients received NAC (600 mg) or placebo orally 3 times a day for 15 days and bronchoalveolar lavage (BAL) fluid and peripheral blood were collected before and at the conclusion of treatment. In our system, NAC treatment was not able to modulate antifungal activity of alveolar macrophages, peripheral blood monocytes (PBM), and polymorphonuclear leukocytes. On the contrary, in vitro NAC treatment at appropriate doses (10 micrograms/ml) significantly enhanced antifungal activity of PBM from COPD patients. This phenomenon is mediated by augmented phagocytic activity and phagosome-lysosome fusion. The lack of correlation between in vivo and in vitro studies could be ascribed to differences in the intracellular concentration of the drug that in vivo does not reach levels capable of inducing macrophage activation. We speculate that in COPD patients who undergo long-term NAC treatment, appropriate schedules and doses of the drug could augment resistance against microbial infections which are often life-threatening in these patients.

Acetylcysteine↗
PubMed1993

Mild prematurity and respiratory functions.

Pulmonary function tests and bronchial reactivity to methacholine (MCH) were measured in 34 randomly selected prematures (21 males, 13 females; mean age 11.6 years; mean gestational age 34.9 weeks; mean birth weight 1980 g) and in 34 siblings (22 males, 12 females; mean age 12.5 years, mean gestational age 39.5 weeks; mean birth weight 3030 g). None had suffered neonatal respiratory distress syndrome or had been artificially ventilated. Prematurely born children had a residual volume (RV) and residual volume/total lung capacity (RV/TLC) significantly (P < 0.01) increased compared to controls, although the mean values of both groups were still within the upper limits of normal. Furthermore, an increase of closing volume/vital capacity and closing capacity/total lung capacity (CC/TLC) was observed in most patients with increased RV and RV/TLC. No significant difference was observed for bronchial responsiveness to MCH between prematurely born and control children (11.8% and 5.9% of hyperreactive subjects, respectively). Maternal smoking during pregnancy was prevalent in prematures with impaired respiratory functions. In conclusion clinically normal children of smoking mothers who have survived prematurity but present some respiratory function impairment compared to their born-at-term siblings, should be fully informed and protected from risk factors for chronic obstructive pulmonary disease (COPD) in adult life.

Bronchial Hyperreactivity↗
PubMed1993

Altered platelet function associated with the bronchial hyperresponsiveness accompanying nocturnal asthma.

BACKGROUND: Nocturnal awakening is a common feature of bronchial asthma, and yet the mechanisms underlying this phenomenon are poorly understood. We investigated whether nocturnal awakening is associated with changes in platelet function with the use of a variety of markers of platelet activation. METHODS: Ten patients with a history of nocturnal asthma and 10 age- and sex-matched healthy control subjects were studied at 10:00 PM, 4:00 AM, and 10:00 AM on 2 consecutive days. The following parameters were tested: forced expiratory volume in 1 second (FEV1), log dose of methacholine inducing a 20% fall in FEV1, platelet count and volume, platelet aggregation induced by collagen or activating factor, and plasma and intraplatelet levels of beta-thromboglobulin and platelet factor 4. RESULTS: We have demonstrated that altered platelet function and platelet activation occurs at 4:00 AM in patients with nocturnal asthma and is associated with the maximum increases in bronchial reactivity. Such changes were not observed in 10 control subjects. Platelet dysfunction has been detected as a reduced aggregatory response of platelets to collagen and platelet activating factor such that up to 5 times more platelet activating factor and 1.5 times more collagen were required to elicit a threshold aggregatory response in asthmatic subjects when compared with control subjects; this difference was evident at all time points tested. Furthermore, at 4:00 AM there were significantly lower levels of intraplatelet beta-thromboglobulin corresponding to the maximum reduction in peak expiratory flow and to the maximal increase in bronchial responses to inhaled methacholine. CONCLUSIONS: These results suggest that platelet activation accompanies nocturnal asthma and further suggest that platelets may play a role in this common clinical condition.

Adult↗
PubMed1993

Inhibition of candidacidal activity of polymorphonuclear cells by alveolar macrophage-derived factor from lung cancer patients.

Culture supernatants of alveolar macrophages (AM) from lung cancer patients are able to inhibit the candidacidal activity of polymorphonuclear cells (PMN) in vitro. This phenomenon is ascribed to a factor secreted in the culture medium by unstimulated AM from tumor-bearing patients, but not from normal subjects. The inhibitor does not apparently affect the phagocytic activity of PMN, but the superoxide release during phagocytosis is significantly impaired when cells are pretreated with supernatants containing the factor. The secretion of the inhibitor seems to be restricted to the pulmonary compartment of lung cancer patients, since culture supernatants of peripheral blood monocytes (PBM) from the same subjects are not capable of depressing the candidacidal activity of PMN. The AM-derived factor is not inactivated after exposure to heat (60 degrees C) and when supernatants are analyzed by HPLC, the inhibitory activity is recovered in the fractions corresponding to a low molecular weight (800 D). In conclusion, AM from lung cancer patients are able to produce a factor capable of inhibiting the antimicrobial activity of PMN. This could account, at least in part, for the enhanced susceptibility to local infections observed in lung cancer patients.

Biological Factors↗
PubMed1993

Mechanism of intracellular candidacidal activity mediated by calcium ionophore in human alveolar macrophages.

In the present study, we investigated the effect of in vitro treatment with calcium ionophore (A23187) on candidacidal activity of human alveolar macrophages (AM) from normal subjects. In vitro incubation of AM with A23187 results in a significant dose-dependent enhancement of candidacidal activity. The availability of Ca2+ and Mg2+ ions in the culture medium is crucial for phagocytosis and killing to occur, but appears irrelevant for the binding between Candida albicans and AM. Enhancement of the killing effect mediated by A23187 does not correlate with increased phagocytic activity; in fact, the availability of ions is required for the phagocytic event, but an increase of cations does not correlate with enhancement of this activity. On the contrary, the augmentation of killing activity correlates with increased production of superoxide anion. Moreover, soluble material endowed with candidacidal activity has been extracted from cytoplasmic granules of AM both unstimulated and following A23187 treatment in vitro. Indeed, the granules extracted contain cationic proteases and, when isolated from stimulated cells, appear to be significantly more cytotoxic for C. albicans with respect to those obtained from unstimulated AM. In conclusion, the results reported here show that the phagocytic and killing events are ion dependent and the enhancement of intracellular candidacidal activity mediated by A23187 in AM is correlated with an augmented anti-Candida activity of cation-activated proteases.

Adult↗
PubMed1992

99mTc-DTPA-surfactant inhalation in adult respiratory distress syndrome (ARDS): a new diagnostic-therapeutic tool.

ARDS is a life-threatening pulmonary disease with a rapidly progressive decline due mainly to multi-organ failure. Death occurs in 50-75% of ARDS cases. The diagnosis and therapy should start in the first six days of this fatal disease when mortality is at its lowest level. The 99mTc-DTPA-measured pulmonary alveolar epithelial permeability (PAEP) is strikingly increased in ARDS even in comparison to heavy smokers. Furthermore, surfactant inhalation has been shown to be of therapeutic value. In five ARDS patients with increased PAEP (T0.5 = 12% pred.) 20 mg/kg of aerosolized surfactant determined a dramatic improvement in blood gases and PAEP (51.8% pred.) No patient remained dependent on ventilatory treatment.

Administration, Inhalation↗
PubMed1992

Prediction of pulmonary immunodeficiency in chronic bronchitis by cutaneous hypoergy to multitest.

Multitest (Pasteur Mérieux) is a plastic disposable device used to assess delayed cutaneous hypersensitivity (DCH) to seven antigens. Hypoergy to Multitest is believed to reflect a status of compromised cell-mediated immunity. Among the many possible pathogenic factors of chronic bronchitis, immunodepression has been little investigated. Indeed, whether lower immunodefence is the cause or the consequence of chronic bronchitis is still a subject of debate. The aim of the study was to evaluate DCH in a large group of patients with chronic obstructive pulmonary disease (COPD) and in a control group, in order to relate DCH (expressed as score, mm) to clinical and functional impairment. One hundred patients with COPD in stable conditions and not undergoing treatment with immunomodulating drugs (mean age, yr, M +/- SD: 66.1 +/- 6.5) and 40 normal controls in the same age range were admitted to the study. Evaluated parameters were: symptoms scores, physical examination, lung function tests and Multitest. Fifty-three percent of the COPD patients were hypoergic compared with 14% of controls. The Multitest score was 10 +/- 10 (mm M +/- SD) in COPD compared with 17 +/- 9 in controls. The Multitest score was significantly related to age (r = -0.45) in the control group, but not in COPD patients. DCH to only three of the seven antigens may predict a response to Multitest, with a sensitivity of 90%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Defective candidacidal activity of alveolar macrophages and peripheral blood monocytes from patients with chronic obstructive pulmonary disease.

We investigated the in vitro candidacidal activity of alveolar macrophages (AM) and peripheral blood monocytes (PBM) from normal subjects or from patients with chronic obstructive pulmonary disease (COPD) displaying defective skin test delayed-type hypersensitivity (DTH) reactivity to seven antigens including Candida albicans. The results showed that cells from patients with COPD were significantly less effective than cells from control subjects in the killing of C. albicans. To explore whether the observed functional impairment could be reversed, interferon-gamma (IFN-gamma) was added to AM and PBM from patients with COPD, alone or in the presence of lipopolysaccharide (LPS) as a suboptimal stimulus. The cells were cultured for 24 h and then assayed for anti-Candida activity. After IFN-gamma treatment, the fungicidal activity of cells from patients with COPD was comparable to that of unstimulated AM or PBM from healthy donors. Treatment with IFN-gamma plus LPS resulted in a further enhancement in the killing of C. albicans. To gain more insight into the mechanisms involved in the modulation of killing, we evaluated the possible stimulating activity of IFN-gamma plus LPS treatment on the secretion of tumor necrosis factor (TNF) and interleukin-1 (IL-1), two cytokines produced by activated macrophages and capable of stimulating natural effectors. The results showed that IFN-gamma plus LPS can indeed stimulate TNF and IL-1 secretion by AM and PBM from patients with COPD. Therefore, a precise role can reasonably be ascribed to these soluble factors in the observed augmentation of candidacidal activity as ascertained by treatment with IFN-gamma plus LPS.

Aged↗