tbuckley/cabot-search huggingface dataset:
Protected bronchoalveolar lavage in the diagnosis of ventilator-associated pneumonia
Authors: B Barreiro, J Dorca, F Manresa, I Catala, L Esteban, R Verdaguer, F Gudiol
Journal: European Respiratory Journal (1996)

The aim of this study was to evaluate the diagnostic efficacy of protected bronchoalveolar lavage (PBAL) in ventilator-associated pneumonia (VAP), and to determine the effect of antibiotic therapy on its microbiological and cytological results. We prospectively studied 102 episodes of suspected VAP in 93 patients. Subsequent follow-up confirmed VAP in 35 of the 102 (34%) cases. In 55 of the 102 (55%) VAP was ruled out, and the diagnosis remained undetermined in 12 of the 102 (12%) episodes. In the VAP group, 30 of the 35 (86%) PBAL (&gt; or = 10(4) colony-forming units (cfu)-mL-1) cultures were positive. In the non-VAP group, 5 of the 55 (9%) PBAL cultures were positive. A Giemsa stain of PBAL samples was performed in 32 of the 35 cases of VAP. Intracellular organisms (ICO) were found in 24 of the 32 (75%) cases. Seven of the other eight cases without evidence of ICO were already on antibiotics. In the non-VAP group, ICO were present in only 1 out of 55 (2%) cases. The mean ICO was significantly higher in the group who had not received antibiotics when compared with those patients previously treated for less than 48 h (p &lt; or = 0.01) and those treated for more than 48 h (p = 0.009). The sensitivity of protected bronchoalveolar lavage quantitative cultures was 87% and the specificity 91%. The sensitivity of cytological analysis for intracellular organisms was 75% and the specificity 98%. According to our results, if the patient is already on antibiotics, the direct examination of protected bronchoalveolar lavage fluid is less reliable, although still helpful.
Can clinical response to cyclosporin in chronic severe asthma be predicted by an in vitro T-lymphocyte proliferation assay?
Authors: AG Alexander, NC Barnes, AB Kay, CJ Corrigan
Journal: European Respiratory Journal (1996)

This study tests the hypothesis that the clinical response to cyclosporin therapy of patients with chronic severe asthma is related to the sensitivity of their T-lymphocytes to the antiproliferative effects of cyclosporin in vitro. In a previous study, we observed such a relationship with glucocorticoids and the same lectin-driven proliferation assay was used in the present study. Peripheral blood mononuclear cells were obtained from 33 patients participating in a cross-over trial of oral cyclosporin therapy during both cyclosporin and placebo treatment periods, and cultured in the presence of phytohaemagglutinin and serial dilutions of cyclosporin and dexamethasone. Proliferation was measured by tritiated thymidine uptake. Both cyclosporin and dexamethasone inhibited T-lymphocyte proliferation in a concentration-dependent manner in vitro at concentrations encompassing those achieved in peripheral blood during therapy in vivo. T-lymphocytes from the asthmatic patients showed a range of sensitivity to the antiproliferative effects of cyclosporin, but this could not be correlated with improvements in peak expiratory flow rate (PEFR) or forced expiratory volume in one second (FEV1) during cyclosporin therapy as compared with placebo. In contrast to previous observations with glucocorticoids, this in vitro T-lymphocyte proliferation assay is not predictive of clinical response to cyclosporin therapy in chronic severe asthmatics.
Calcium-independent and steroid-resistant nitric oxide synthase activity in human paranasal sinus mucosa
Authors: JO Lundberg, E Weitzberg, J Rinder, A Rudehill, O Jansson, NP Wiklund, JM Lundberg, K Alving
Journal: European Respiratory Journal (1996)

Nitric oxide (NO) is present in the human nasal airways and originates primarily from the paranasal sinuses. Immunohistochemical studies and messenger ribonucleic acid (mRNA) in situ hybridization indicate that a type-2 NO synthase (NOS) is constitutively expressed in healthy sinus epithelium. We have further characterized sinus NOS activity by studying the enzymatic conversion of L-arginine to L-citrulline in biopsies from sinus mucosa. Maxillary sinus biopsies were obtained from nine healthy subjects during reconstructive facial surgery. In addition, nasal NO concentrations in nine controls were compared with those found in five patients treated with high systemic doses of glucocorticosteroids. Finally, the effects of i.v. L-arginine infusion on nasal cavity NO concentrations were studied in six healthy subjects. Ca(2+)-independent NOS activity was found in all biopsies and was five times higher than Ca(2+)-dependent activity (179 +/- 64 and 36 +/- 17 pmol.g-1.min, respectively). There was no difference in nasal NO levels between controls (344 +/- 21 parts per billion (ppb)) and steroid-treated patients (342 +/- 36 ppb). Nasal NO levels increased up to 35% following i.v. infusion of L-arginine. We conclude that NOS activity in healthy sinus mucosa is predominantly Ca(2+)-independent and this NOS is not downregulated by systemic steroids. Furthermore, L-arginine infusion increases nasal airway NO excretion in vivo, indicating that the substrate concentration is a rate-limiting factor under basal conditions. These findings further support the notion that sinus NOS is identical or very closely related to the type-2 NOS; however, the regulation of expression seems to be fundamentally different from that described previously for this NOS isoform.
Longitudinal assessment of hypercapnic ventilatory drive after tracheotomy in a patient with the Prader-Willi syndrome
Authors: D Gozal, JE Torres, AA Menendez
Journal: European Respiratory Journal (1996)

The clinical course and changes in hypercapnic ventilatory drive over time were serially assessed before and after tracheostomy placement in a 14 year old, morbidly obese female patient with Prader-Willi syndrome, severe obstructive sleep apnoea, and obesity-hypoventilation syndrome. A tracheostomy became necessary after supplemental oxygen and continuous positive airway pressure (CPAP) had failed to improve the severity of nocturnal hypoventilation. Continued improvement in the slope to rebreathing hyperoxic hypercapnia occurred from 2-10 weeks after tracheotomy in conjunction with night-time bilevel pressure ventilation, and remained unchanged thereafter. In contrast, increases in mean resting minute ventilation at an end-tidal carbon dioxide tension (PET,CO2) of 8 kPa (60 mmHg) were documented even after 30 weeks. This case study illustrates the time-frame of dynamic ventilatory changes occurring after removal of upper airway resistance and normalization of nocturnal alveolar ventilation.
Disinfectant use as a risk factor for atopic sensitization and symptoms consistent with asthma: an epidemiological study
Authors: L Preller, G Doekes, D Heederik, R Vermeulen, PF Vogelzang, JS Boleij
Journal: European Respiratory Journal (1996)

Exposure to some nonallergenic compounds has been shown to increase the risk of atopic sensitization and asthmatic symptoms. In order to gain more insight into the largely unknown aetiology of respiratory symptoms in pig farmers, we studied the role of nonallergic exposure. We evaluated associations between chronic respiratory symptoms, specific and total serum immunoglobulin E (IgE) levels, use of disinfectants, and endotoxin exposure levels in a population of 194 Dutch pig farmers. Atopic sensitization (defined as increased production of IgE to common allergens) was found to occur more frequently in farmers who used disinfectants containing quaternary ammonium compounds (QACs) (odds ratio (OR) 7.4; 95% confidence interval (95% CI) 1.3-43.1). ORs for other disinfectants ranged 2.3-4.1 (NS). Atopic sensitization was not found to occur more frequently in farmers with a high endotoxin exposure. The use of disinfectants was only related to respiratory symptoms consistent with asthma in atopics. This is illustrated by the significantly elevated ORs for farmers with IgE to common allergens (house dust mite, grass pollen, birch pollen), and who used disinfectants containing QACs, in the total population and in a subgroup of the total population restricted according to bronchial hyperresponsiveness to histamine (symptomatics with a provocation dose of histamine producing a &gt; or = 10% decrease in forced expiratory volume in one second (PC10) &lt; or = 16 mg.mL-1, compared with asymptomatics with a PC10 &gt; 16 mg.mL-1) (OR 4.4, 95% CI 1.3-14.6; and OR 8.2, 95% CI 1.6-42.6, respectively). Atopy and use of QACs and endotoxin exposure level taken individually were not associated with respiratory symptoms. A combination of atopic sensitization and high endotoxin exposure (&gt; 101 ng.m-3) was strongly associated with respiratory symptoms in the restricted population (OR 6.1; 95% CI 1.0-36.2). Our results suggest that occupational exposure to nonallergenic agents (disinfectants) may induce immunoglobulin E sensitization to common aeroallergens, and that the combination of atopy and exposure to nonallergenic agents (disinfectants and endotoxin) is an important risk factor for development of symptoms consistent with asthma.
Negative pressure ventilation in the treatment of acute respiratory failure: an old noninvasive technique reconsidered
Authors: A Corrado, M Gorini, G Villella, E De Paola
Journal: European Respiratory Journal (1996)

Noninvasive mechanical ventilatory techniques include the use of negative and positive pressure ventilators. Negative pressure ventilators, such as the "iron lung", support ventilation by exposing the surface of the chest wall to subatmospheric pressure during inspiration; whereas, expiration occurs when the pressure around the chest wall increases and becomes atmospheric or greater than atmospheric. In this review, after a description of the more advanced models of tank ventilators and the physiological effects of negative pressure ventilation (NPV), we summarize the recent application of this old technique in the treatment of acute respiratory failure (ARF). Several uncontrolled studies suggest that NPV may have a potential therapeutic role in the treatment of acute on chronic respiratory failure in patients with chronic obstructive pulmonary disease and restrictive thoracic disorders, reducing the need for endotracheal intubation. In the paediatric field, after substantial technical improvement, NPV has been successfully reintroduced for the treatment of ARF due to neonatal distress syndrome and bronchopulmonary dysplasia, and for the weaning from positive pressure ventilation in intubated patients. The positive results of these reports need to be formally confirmed by further prospective and controlled studies before recommending the generalized use of negative pressure ventilation in acute respiratory failure as a standard of care.
A portable device based on the interrupter technique to measure bronchodilator response in schoolchildren
Authors: PD Bridge, H Lee, M Silverman
Journal: European Respiratory Journal (1996)

A new device for measuring airway resistance following brief airflow interruption (Microlab 4000; Micromedical Ltd, UK) was evaluated in 25 asthmatic school children in comparison with well-established methods. Airway resistance was measured during brief airflow interruption (Rint), before and after administration of salbutamol 200 micrograms by metered-dose inhaler, and in the spirometric parameters, forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF), and total respiratory system resistance at 6 Hz (Rrs,6) measured by the forced oscillation technique (FOT). The sensitivity index (SI) (mean change/baseline standard deviation) was calculated for each subject. At baseline, interrupter conductance, the reciprocal of Rint, correlated well with FEV1 (r = 0.837; p &lt; 0.001) and PEF (r = 0.773; p &lt; 0.001), and Rint correlated highly with Rrs,6 (r = 0.942; p &lt; 0.001). The median intrasubject coefficient of variation of the interrupter method was higher than the FOT or either spirometric parameter; Rint 11%, Rrs,6 9%, FEV1 5% and PEF 5%. However, the sensitivity to detect change after bronchodilator, expressed as the median SI, did not differ significantly between measurements: Rint 3.5, Rrs,6 3.6, FEV1 2.4 and PEF 3.0. A significant response (SI &gt; 2) was shown by the interrupter in 22 of the subjects compared with 16 by FEV1. The interrupter technique is useful for assessing changes in airway calibre in asthmatic school children, with a sensitivity at least as good as standard methods. Such a device could be of particular value in those too young to perform spirometry.
Pulmonary hypertension after transjugular intrahepatic portosystemic shunt (TIPS)
Authors: RM van der Heijde, JS Lameris, B van den Berg, CA Wagenvoort, C Hilvering, HR van Buuren
Journal: European Respiratory Journal (1996)

We reported the case of a patient in whom severe, and ultimately fatal, pulmonary hypertension developed 1.5 yrs after transjugular intrahepatic portosystemic shunt (TIPS). Pulmonary artery pressures were not affected by 100% oxygen, prostacyclin or nifedipine. Postmortem examinations showed pulmonary and vascular abnormalities typical of pulmonary hypertension. Pulmonary artery pressures should be measured in each patient with otherwise not readily explained dyspnoea following transjugular intrahepatic portosystemic shunt.
Repeated allergen exposure enhances excitatory nonadrenergic noncholinergic nerve-mediated bronchoconstriction in sensitized guinea-pigs
Authors: N Kageyama, M Ichinose, A Igarashi, M Miura, H Yamauchi, Y Sasaki, J Ishikawa, M Tomaki, K Shirato
Journal: European Respiratory Journal (1996)

The effect of repeated allergen inhalation challenge on the airway excitatory nonadrenergic noncholinergic (e-NANC) nerve-mediated bronchoconstrictor response was studied in ovalbumin (OA) sensitized guinea-pigs. Three weeks after sensitization, OA inhalation, 0.03% for 3 min (challenged group), or saline inhalation (control group) was repeated every day for 4 weeks. The e-NANC nerve function was examined in vitro by means of isometric tension measurement of main bronchi. After pretreatment with atropine (10(-6) M) and propranolol (10(-6) M), we performed electrical field stimulation (EFS) or exogenous neurokinin A (NKA) administration. In the challenged group, EFS-induced main bronchial contraction was significantly greater than that of the control group (p &lt; 0.05 or p &lt; 0.01), but exogenous NKA-mediated responses were almost the same in both groups. The e-NANC-induced main bronchial contractions after EFS were enhanced by pretreatment with the neutral endopeptidase inhibitor, phosphoramidon, to the same degree in the control and challenged groups, indicating that the peptide degradation mechanisms were not impaired even in the challenged group. Substance P immunoreactivities in the lung of the challenged group were significantly higher than those of the control group. These results suggest that chronic airway inflammation after repeated allergen challenge increases excitatory nonadrenergic noncholinergic nerve function, possibly by enhancing sensory neuropeptide production and/or release.
Alveolar epithelial lining fluid cellularity, protein and endothelin-1 in children with congenital heart disease
Authors: J Grigg, S Kleinert, RL Woods, CJ Thomas, P Vervaart, JL Wilkinson, CF Robertson
Journal: European Respiratory Journal (1996)

This study applied bronchoalveolar lavage (BAL) to children with congenital heart disease (CHD) prior to elective cardiac catheterization (n = 48), to determine the influence of pulmonary blood flow and viral infection on the alveolar epithelial lining fluid (ELF) concentration of leucocytes, protein and endothelin-1 (ET-1). Lower respiratory tract (LRT) viral infection was defined as either a positive immunofluorescence for virus, or a virus cultured from the bronchoalveolar lavage fluid (BALF). Haemodynamic status was determined at cardiac catheterization. Normative data for BALF, but not ELF parameters, were obtained from 26 asymptomatic, noninfected normal children undergoing elective surgery. In the absence of LRT infection, the BALF macrophage, lymphocyte and neutrophil differential in CHD was not significantly different from the normal controls. In CHD, both increased pulmonary-to-systemic flow ratio (Q'p/Q's) and increased pulmonary artery-to-left ventricular pressure ratio PAP/LVP were associated with a decrease in ELF protein (rs = -0.59; p &lt; 0.0001; and rs = -0.50; p &lt; 0.0001 respectively). A respiratory virus was isolated from the BALF in 8 (17%) of CHD children. Virus isolation was associated with an increased ELF total protein (p &lt; 0.05 vs no infection), a decreased alveolar macrophage differential count (p &lt; 0.01), and an increased neutrophil differential count (p &lt; 0.05). ET-1 was detected in the BALF of 83% of the noninfected CHD children compared to only 23% of the controls (p &lt; 0.001). ELF ET-1 concentrations did not correlate with haemodynamic status in CHD, but were up to 100 times higher than paired plasma levels. We conclude that, in congenital heart disease, both lower respiratory tract viral infection and increased pulmonary blood flow and/or pulmonary vascular pressure influence the alveolar milieu. High alveolar epithelial lining fluid concentrations of endothelin-1 occur in congenital heart disease, but the stimulus for pulmonary endothelin-1 production is unclear.
Altered immunosuppressive activity of alveolar macrophages in farmer's lung disease
Authors: A Dakhama, E Israel-Assayag, Y Cormier
Journal: European Respiratory Journal (1996)

Since normal alveolar macrophages (AMs) can suppress T-cell proliferation to mitogenic and antigenic stimuli both in vitro and in vivo, we questioned whether an altered AM immunosuppressive activity could account for the alveolar lymphocytosis observed in farmer's lung (FL) and whether granulocyte/macrophage colony-stimulating factor (GM-CSF), a cytokine able to abrogate AM-induced immunosuppression, is involved in the process. The ability of different concentrations of AMs to inhibit lymphocyte proliferation in response to the T-cell-specific mitogen phytohaemagglutin (PHA) after in vitro culture was tested in three groups of subjects: 12 patients with FL; four asymptomatic farmers (AS); and six normal volunteers (N). Release of GM-CSF by AMs was also measured. At all ratios tested, AMs from patients with FL did not suppress the lymphoproliferation but instead had an enhancing effect. In AS, AMs enhanced the proliferation at a lower ratio but inhibited it at high ratios. In N subjects, as described previously, AMs increasingly inhibited the blastogenesis of lymphocytes (L) at increasing ratios of AM:L. In some patients with FL, AMs spontaneously released more GM-CSF than in normal volunteers (206 +/- 84 versus 29 +/- 14 pg.mL-1, respectively). In AS, GM-CSF release was intermediate (74 +/- 36 pg.mL-1). In conclusion, a defect in the ability of alveolar macrophages to suppress the proliferation of lymphocytes in the lung of patients with farmer's lung is a major factor accounting for the development of the observed lymphocytic alveolitis. Granulocyte/macrophage colony-stimulating factor could be one factor which may contribute to this alteration.
Prevention of asthma
Authors: JK Peat
Journal: European Respiratory Journal (1996)

Environmental factors which have changed in the last decade or so appear to be largely responsible for the increase in the prevalence of asthma in affluent countries. It should, therefore, be possible to design interventions to reverse these recent trends and reduce the incidence of asthma. Primary preventive strategies have the potential not only to reduce acquisition of sensitization to common allergens and the risk that symptoms will develop subsequently, but also to reduce morbidity in those who already have persistent disease. There is accumulating epidemiological evidence that a dietary exess of sodium and omega-6 fatty acids, a dietary deficiency of antioxidant vitamins and omega-3 fatty acids, reduced rates of breastfeeding and exposure to allergens and environmental tobacco smoke are all involved in the aetiology of asthma. The modification of these factors has the potential to reduce the incidence and thus the prevalence of this disease. Environmental intervention should be particularly effective in children who have inherited or acquired characteristics which put them at high risk of developing asthma. With the evidence now available, it seems reasonable to assume that interventions which are based on our current knowledge of risk factors could achieve a 50% reduction in the prevalence of asthma in the next generation of children.
"Blind" protected specimen brushing versus bronchoscopic techniques in the aetiolological diagnosis of ventilator-associated pneumonia
Authors: S Bello, A Tajada, E Chacon, MC Villuendas, A Senar, M Gascon, FJ Suarez
Journal: European Respiratory Journal (1996)

The aetiological diagnosis of nosocomial pneumonia in intensive care unit (ICU) patients requires a valid, cheap and safe method. This method should be suitable for all mechanically-ventilated patients and all ICUs. The aim of this study was to assess the diagnostic yields of three methods: "blind" bronchial brushing (Accu-Cath)(protective specimen brush-nonbronchofibroscopic (PSB-non BF)); bronchofibroscopic protected specimen brushing (PSB-BF) and bronchoalveolar lavage (BAL). We prospectively studied the diagnostic values of the three methods as well as the agreement between microbiological results in 74 patients with 88 episodes of clinically suspected ventilator-associated pneumonia (VAP) and 22 control subjects. VAP episodes were also divided into those with (n = 24) and without antibiotic pretreatment (n = 64), and into those with (n = 78) and without (n = 10) right lower lobe infiltrates on chest radiography. No differences were found as regards the bacteriological yield of the three techniques. Furthermore, the rate of concordant results was high; 92% for PSB-BF and BAL; 84% for PSB-nonBF and BAL; 85% for PSB-nonBF and PSB-BF; and 85% for PSB-nonBF combined with both bronchoscopic techniques. The diagnostic yields in suspected VAP were 66, 59 and 56% for PSB-nonBF, PSB-BF and BAL, respectively. We conclude that "blind" bronchial brushing has similar accuracy to bronchoscopic techniques commonly used in the diagnosis of ventilator-associated pneumonia, constituting an interesting alternative in hospitals where fibreoptic bronchoscopy is not available.