Patient with multiple acyl-CoA dehydrogenation deficiency disease and FLAD1 mutations benefits from riboflavin therapy

Multiple acyl-CoA dehydrogenation deficiency is genetically heterogenous metabolic disease with mutations in genes involved in electron transfer to the mitochondrial respiratory chain. Disease symptoms vary from severe neonatal form to late-onset presentation with metabolic acidosis, lethargy, vomiting, muscle pain and weakness. Riboflavin therapy has been shown to ameliorate diseases symptoms in some of these patients. Recently, mutations in FAD synthase have been described to cause multiple acyl-CoA dehydrogenation deficiency. We describe here the effect of riboflavin supplementation therapy in a previously reported adult patient with multiple acyl-CoA dehydrogenation deficiency having compound heterozygous gene variations in FLAD1 (MIM: 610595) encoding FAD synthase. We present thorough clinical history including laboratory investigations, muscle MRI, muscle biopsy and spiroergometric analyses comprising of a follow-up of 20 years. Our data suggest that patients with adult-onset multiple acyl-CoA dehydrogenation deficiency with FLAD1 gene mutations also benefit from long-term riboflavin therapy.

Associations between sports participation, cardiorespiratory fitness, and adiposity in young adult twins

Exercise behavior, cardiorespiratory fitness, and obesity are strongly influenced by genetic factors. By studying young adult twins, we examined to what extent these interrelated traits have shared genetic and environmental etiologies. We studied 304 twin individuals selected from the population-based FinnTwin16 study. Physical activity was assessed with the Baecke questionnaire, yielding three indexes: sport index, leisure-time index, and work index. In this study, we focused on sport index, which describes sports participation. Body composition was determined using dual-energy X-ray absorptiometry and cardiorespiratory fitness using a bicycle ergometer exercise test with gas exchange analysis. The Baecke sport index was associated with high maximal oxygen uptake adjusted for lean body mass (Vo(2max)[adj]) (r = 0.40), with low body fat percentage (BF%) (r = -0.44) and low waist circumference (WC) (r = -0.29). Heritability estimates for the key traits were as follows: 56% for sport index, 71% for Vo(2max)[adj], 77% for body mass index, 66% for WC, and 68% for BF%. The association between sport index and Vo(2max) was mostly explained by genetic factors (70%), as were both the association between sport index and BF% (71%) and that between sport index and WC (59%). Our results suggest that genetic factors explain a considerable part of the associations between sports participation, cardiorespiratory fitness, and obesity.

Genetic susceptibility to asbestos-related fibrotic pleuropulmonary changes

The objective of this study was to determine whether genetic polymorphisms in enzymes that metabolise oxidative agents modify the individual susceptibility to developing asbestos and smoking-related pleuropulmonary changes. Nine polymorphisms of six genes (EPHX1, GSTM1, GSTM3, GSTP1, GSTT1 and NAT2) were genotyped from 1,008 Finnish asbestos-exposed workers. The genotype data were compared to signs of lung fibrosis and pleural thickenings, as well as with total lung capacity, single-breath diffusing capacity of the lung for carbon monoxide (D(L,CO)) and specific diffusing capacity (expressed as D(L,CO) per unit of alveolar volume (V(A))). The GSTT1 deletion polymorphism was associated with fibrotic changes (p=0.003), and decreased D(L,CO) (p=0.02) and D(L,CO)/V(A) (p=0.002), and the GSTM1 deletion polymorphism was associated with the greatest thickness of pleural plaques (p=0.009). On further analysis, the GSTT1 null genotype was found to pose over a three-fold risk for severe fibrotic changes (OR 3.12, 95% CI 1.51-6.43), and around two-fold risks for decreased D(L,CO) (OR 1.77, 95% CI 1.06-2.95) and D(L,CO)/V(A) (OR 2.37, 95% CI 1.33-4.23). In addition, the GSTM1 null genotype showed an elevated risk (OR 1.36, 95% CI 1.03-1.80) for thicker pleural plaques. Our data suggest that inherited detoxification capacity may affect the development and severity of asbestos and smoking-related nonmalignant pulmonary changes.

Matrix metalloproteinases-7, -8, -9 and TIMP-1 in the follow-up of diisocyanate-induced asthma

BACKGROUND

Diisocyanate-induced asthma (DIA) is known to be associated with poor prognosis. We wished to clarify if matrix metalloproteinases (MMP)-7, -8 or -9 or tissue inhibitor of matrix metalloproteinases (TIMP-1) are associated with the functional or inflammatory outcome in DIA patients.

METHODS

This is a longitudinal study where 17 patients with DIA diagnosed by a specific challenge test to diisocyanates were monitored. Exposure to diisocyanates was terminated seven (mean) months before the challenge test. The studies included spirometry, histamine challenge test and bronchoscopy. MMP-7, MMP-8, TIMP-1 [Enzyme-linked immunosorbent assay (ELISA)- and immunofluorometric assay-methods], MMP-9 (ELISA and zymography), interferon-gamma, tumour necrosis factor-alpha, interleukin-6, -8, -15, -17, CXCL-5/ENA-78, monocyte chemoattractant protein-1 and macrophage inhibitory factor (MIF) (ELISA) were assayed from bronchoalveolar lavage (BAL) fluid. Inhaled steroid therapy was initiated after the examinations, which were repeated at 6 months and at 3 years during the treatment. The results were compared with those of 15 healthy controls.

RESULTS

Inhaled steroid medication increased BAL levels of MMP-9 and MMP-9/TIMP-1 and decreased MMP-7 and MMP-7/TIMP-1. The increase in MMP-9 levels was associated with a decline in the TH-2 type inflammation.

CONCLUSIONS

Our data suggest that reduced TH-2 type inflammation in DIA after inhaled steroid medication is reflected as elevated MMP-9 and MMP-9/TIMP-1 levels in BAL. MIF may be the inducer of MMP-9. This might point to some protective role for MMP-9 in DIA.

Upper abdominal symptoms in patients with Type 1 diabetes: unrelated to impairment in gastric emptying caused by autonomic neuropathy

AIMS

Diabetic gastroparesis is a common condition occurring in some 30-50% of patients with long-term diabetes. Some studies have found a relationship between autonomic neuropathy and diabetic gastroparesis. In addition to autonomic neuropathy, acute changes in plasma glucose concentration can also affect gastric emptying. The objective was to examine the relationship between autonomic nerve function, glucose concentration, gastric emptying, and upper abdominal symptoms in Type 1 diabetic patients.

METHODS

Gastric emptying of solids and liquids was measured with scintigraphy in 27 patients with longstanding Type 1 diabetes with upper abdominal symptoms. Autonomic nerve function was examined by standardized cardiovascular tests, and plasma glucose concentrations were measured during scintigraphy. Severity of abdominal symptoms and quality of life were explored by validated questionnaires.

RESULTS

Seven patients (26%) had delayed gastric emptying of solids and three (11%) of liquids. Mean gastric half-emptying time of solids was 128 +/- 116 min and of liquids 42 +/- 30 min. Of the 26 patients undergoing tests, 16 (62%) had autonomic nerve dysfunction. Autonomic neuropathy score (1.6 +/- 1.7) correlated positively with the gastric emptying rate of solids (P = 0.006), a rate unrelated to symptom scores or plasma glucose concentrations during scintigraphy. Quality of life in patients with abdominal symptoms was lower than in the normal Finnish population.

CONCLUSIONS

Impaired gastric emptying of solids in patients with Type 1 diabetes is related to autonomic neuropathy, but not to actual glycaemic control. The upper abdominal symptoms observed in these patients cannot be explained, however, by impaired gastric emptying.

Exhaled nitric oxide in specific challenge tests to assess occupational asthma

Exhaled nitric oxide (NO) is a marker of eosinophilic inflammation of the airway mucosa accompanying changes in the clinical condition of asthma. Allergen exposure has been associated with delayed elevation of exhaled NO. The aim of this study was to assess the asthmatic airway inflammation with exhaled NO measurements during specific bronchial challenge tests with occupational agents. Forty patients with suspected occupational asthma were investigated. Specific bronchial challenge tests were performed with forced expiratory volume in one second or peak expiratory flow follow-up, supplemented by exhaled NO measurements before and 24 h after challenge tests. In active challenges, which induced bronchoconstriction, a significant mean increase of exhaled NO concentration was noted. In patients with a normal or slightly increased (<14.5 parts per billion (ppb)) basal NO level and a late bronchoconstriction, a significant increase in exhaled NO was seen. Patients with a high basal NO level (>14.5 ppb) and a significant bronchoconstriction did not show a significant NO elevation. Challenge tests without bronchoconstriction were not associated with a significant elevation of exhaled NO. Exhaled nitric oxide measurements can be used to indicate the development of airway inflammation accompanying late asthmatic reaction after bronchial challenge tests in patients with a normal or slightly increased basal nitric oxide concentration.

Exposure to 2,4- and 2,6-toluene diisocyanate (TDI) during production of flexible foam: determination of airborne TDI and urinary 2,4- and 2,6-toluenediamine (TDA)

Occupational exposure to 2,4- and 2,6-toluene diisocyanate (2,4- and 2,6-TDI) was measured during the production of flexible foam. The usefulness of urinalysis of the TDI-derived amines, 2,4- and 2,6-toluenediamine (2,4- and 2,6-TDA), for exposure assessment was compared with air monitoring. Urine samples were collected from 17 employees at two plants. The workers' personal exposure was measured using 1-(2-methoxyphenyl)-piperazine (2MP)-impregnated glass fibre filters for sampling and high-performance liquid chromatography (HPLC) with ultraviolet (UV) and electrochemical (EC) detection for quantification. The limit of detection (LOD) of 2,4- and 2,6-TDI was 0.01 microtg ml(-1) for a 20 microl injection. The precision of sample preparation, expressed as the relative standard deviation (RSD), was 0.6% with UV detection and 0.8% with EC detection at a 2,4-TDI concentration of 0.2 microg ml(-1) (n = 6). For 2,6-TDI, the corresponding RSDs were 0.5% and 0.8%. The urinary 2,4- and 2,6-TDA metabolites were determined after acid hydrolysis as heptafluorobutyric anhydride derivatives by gas chromatography-mass spectrometry. The LOD in urine was 0.35 nmol l(-1) for 2,4-TDA and 0.04 nmol l(-1) for 2,6-TDA. The precision (RSD) of six analyses of human urine spiked to a concentration of 100 nmol l(-1) was 3.7% for 2,4-TDA and 3.6% for 2,6-TDA. There was a trend for linear correlation between urinary TDA concentration and the product of airborne TDI concentration and sampling time. Urinalysis of TDA is proposed as a practical method for assessing personal exposures in workers exposed intermittently to TDI.

Glutathione S-transferase genotypes and allergic responses to diisocyanate exposure

Diisocyanates are the most common low molecular weight chemicals to cause occupational asthma. However, only some 5-10% of exposed workers develop asthma, which suggests an underlying genetic susceptibility. Diisocyanates and their metabolites may be conjugated with glutathione by glutathione S-transferases (GSTs). We examined whether polymorphisms in the GSTM1, GSTM3, GSTP1 and GSTT1 genes modify allergic responses to diisocyanate exposure. The study population consisted of 182 diisocyanate exposed workers, 109 diagnosed with diisocyanate-induced asthma and 73 without asthma. Lack of the GSTM1 gene (null genotype) was associated with a 1.89-fold risk of diisocyanate-induced asthma [95% confidence interval (CI) 1.01-3.52]. Moreover, among the asthma patients, the GSTM1 null genotype was associated with lack of diisocyanate-specific immunoglobulin (Ig)E antibodies [odds ratio (OR) 0.18, 95% CI 0.05-0.61] and with late reaction in the specific bronchial provocation test (OR 2.82, 95% CI 1.15-6.88). Similarly, GSTM3 AA genotype was related to late reaction in the specific bronchial provocation test (OR 3.75, 95% CI 1.26-11.2). The GSTP1 Val/Val genotype, on the other hand, was related to high total IgE levels (OR 5.46, 95% CI 1.15-26.0). The most remarkable effect was seen for the combination of GSTM1 null and the GSTM3 AA genotype which was strongly associated with lack of diisocyanate-specific IgE antibodies (OR 0.09, 95% CI 0.01-0.73) and with late reaction in the bronchial provocation test (OR 11.0, 95% CI 2.19-55.3). The results suggest, for the first time, that the polymorphic GSTs, especially the mu class GSTs, play an important role in inception of ill effects related to occupational exposure to diisocyanates.

Exposure to 4,4'-methylenediphenyl diisocyanate (MDI) during moulding of rigid polyurethane foam: determination of airborne MDI and urinary 4,4'-methylenedianiline (MDA)

Occupational exposure to 4,4'-methylenediphenyl diisocyanate (MDI) was measured during moulding of rigid polyurethane foam. The aim of the study was to find out whether an MDI-derived urinary amine metabolite could be detected in the urine of workers exposed to apparently low levels of MDI. Airborne MDI was sampled on 1-(2-methoxyphenyl)-piperazine (2MP)-impregnated glass fibre filters and determined by high-performance liquid chromatography (HPLC) using ultraviolet (UV) and electrochemical (EC) detection. The limit of detection of MDI was 3 ng ml-1 for a 20 microliters injection. The precision of sample preparation, expressed as relative standard deviation (RSD), was 1.3% with UV detection and 2.1% with EC detection at a concentration of 70 ng MDI ml-1 (n = 6). The 2MP-MDI derivative was stable at +4 degrees C up to eight weeks. The accuracy of the method was validated in an international quality control programme. Workers (n = 57) from three different factories participated in the study. Urinary 4,4'-methylenedianiline (MDA) metabolite was determined after acid hydrolysis as heptafluorobutyric anhydride derivatives by gas chromatography-mass spectrometry using chemical ionisation and monitoring negative ions. The limit of detection in urine was 0.2 nmol l-1. The precision of six analyses for a urine sample spiked to a concentration of 1 nmol l-1 was 29% (RSD). The MDI concentrations were below the limit of detection in most (64%) of the air samples collected in the worker's breathing zone. Still, detectable amounts of MDA were found in 97% of the urine samples. Monitoring of urinary MDA appears to be an appropriate method of assessing MDI exposure in work environments with low or undetectable MDI concentrations in the workplace air.

Lung sounds in asbestos induced pulmonary disorders

The aim of the study was to compare the lung sounds in patients with asbestos related pulmonary disorders with findings in high-resolution computed tomography (HRCT), and with lung function variables, in order to find out associations of acoustic changes with radiological fibrosis, emphysema or with pulmonary gas transfer functions. Sixty-four patients with asbestos-related pleural disease, with or without pulmonary disease, were studied. Lung sound recording and analysis was carried out with a computerized lung sound analyser, and HRCT of the chest, as well as forced spirometry and diffusing capacity measurement were performed. The fibrosis score correlated positively with the quartile frequencies of the power spectrum of lung sounds in inspiration (f50) and expiration (f50) and crackle count in inspiration, as well as negatively with diffusing capacity. When the patients with crackling sounds and significant fibrosis were excluded (n=18), emphysema correlated negatively with expiratory quartile frequencies of the power spectrum, with f25 and f50. Furthermore, diffusing capacity correlated with inspiratory f25 and forced expiratory volume in one second with inspiratory f50 when crackles and fibrosis were excluded. Changes in lung sounds were significantly associated with radiologically verified abnormalities and gas transfer of pulmonary tissue. High sound frequencies were associated with fibrotic changes of the lung while low sound frequencies with pulmonary emphysema. Acoustic analysis gives complementary clinical information for evaluation of asbestos-related pulmonary disorders.

Occupational IgE-mediated asthma, rhinoconjunctivitis, and contact urticaria caused by Easter lily (Lilium longiflorum) and tulip

BACKGROUND

We report on IgE-mediated asthma, rhinoconjunctivitis, and contact urticaria to two Liliaceae plants, tulip and Easter lily (Lilium longiflorum), diagnosed in a floral shop worker.

METHODS

Occupational asthma was diagnosed according to patient history, PEF monitoring, and a work-simulating provocation test. Flower-specific IgE was studied, and RAST inhibition tests were performed.

RESULTS

Skin prick testing showed positive reactions to tulip, Easter lily, and chrysanthemum. Total IgE was 180 kU/I, and specific IgE to tulip was 2.6 and to Easter lily 6.5 kU/I. In the RAST-inhibition test, no cross-reactivity was found. Occupational asthma was diagnosed by peak flow monitoring at work and at home, as well as specific inhalation challenge with Easter lily, with an immediate 18% reduction in PEF. In addition, contact urticaria and conjunctivitis were diagnosed. After a 9-year follow-up without exposure to lilies, the skin prick tests to L. longiflorum and tulip were still positive, but the specific IgE had disappeared.

CONCLUSIONS

A case of IgE-mediated occupational asthma, rhinoconjunctivitis, and contact urticaria caused by L. longiflorum and tulip is presented. RAST inhibition tests indicated concomitant sensitization to the two Liliaceae plants.

Occupational respiratory hypersensitivity caused by preparations containing acrylates in dental personnel

BACKGROUND

Allergic contact dermatitis caused by acrylate compounds is common in dental personnel; they also often complain of work-related respiratory or conjunctival symptoms.

OBJECTIVE

The aim of the present study was to report the cases of acrylates induced respiratory hypersensitivity in dental personnel diagnosed in Finland during the last 6 years.

METHODS

Occupational asthma, rhinitis, laryngitis and pharyngitis cases were diagnosed according to patient history, PEF monitoring, and a work-simulating provocation test.

RESULTS

Twelve cases of respiratory hypersensitivity caused by acrylates diagnosed in dental personnel (six dentists and six dental nurses) in 1992-97 are reported. During this period one case of conjunctivitis and one of laryngitis have been published separately. Nine cases of occupational asthma, two rhinitis cases, and one laryngitis case were verified according to the challenge tests with dental acrylate compounds (acrylates, methacrylates and epoxy acrylates). Only three patients had positive skin-prick test reactions to common environmental allergens, and none reacted to acrylates in the skin-prick tests. Five patients had an elevated total IgE (>110 kU/L). PEF follow-up showed an occupational effect in all examined eight patients with diagnosed asthma. The mean duration of exposure to acrylates was 22 years, and the duration of respiratory symptoms 8 years.

CONCLUSIONS

The results indicate that acrylates constitute an important hazard for dental workers. The mechanism of respiratory hypersensitivity is still unknown, and it is probably not IgE-mediated.

A new versatile PC-based lung sound analyzer with automatic crackle analysis (HeLSA); repeatability of spectral parameters and sound amplitude in healthy subjects

A versatile PC-based lung sound analyzer has been developed for short-term recording and analysis of respiratory sounds in research and clinical applications. The system consists of two sound sensors, a flow sensor, a filtering signal amplifier and a PC with a data acquisition card and software for measurement and analysis of the sounds. The analyses include phonopneumography, time expanded waveform analysis, spectral analysis with time averaged Fast Fourier Transform, frequency analysis in time domain (sonogram), and automatic detection and waveform analysis of crackles. Short-term repeatability of spectral parameters of tracheal and lung sounds was studied in 10 healthy subjects. The coefficients of variation (CoV) of the averaged quartile frequencies (F25, F50 and F75) of lung sounds during flow-controlled tidal breathing were 3.7, 4.0 and 8.9% in expiration and 2.7, 3.5 and 4.5% in inspiration, respectively. CoVs of the averaged F25, F50 and F75 of expiratory tracheal sounds were 6.9, 3.0 and 2.4%, and those of inspiratory tracheal sounds 6.3, 2.6 and 3.3%, respectively. Examples of lung sound analysis of samples containing adventitious sounds such as crackles and wheezes are presented. The results indicate that the median frequency has the best repeatability of quartile frequencies of breath sounds and they suggest that the variations of those parameters are low enough for diagnostic purposes. The results also suggest that the analyzer can be a useful new tool for pulmonary research in the fields of physiological and clinical short-term studies of respiratory sounds.

Distribution of crackles on the flow-volume plane in different pulmonary diseases

A new method to represent and evaluate crackles on the flow-volume plane is described. Characteristic crackle patterns were found in patients with pneumonia, bronchiectasis, chronic obstructive pulmonary disease, heart failure and cryptogenic fibrosing alveolitis. In addition to visual assessment, simple statistical parameters were used to describe the observed pathological phenomena.

Rhinitis caused by ninhydrin develops into occupational asthma

Ninhydrin (2,2-dihydroxy-1,3-indanedione or 1,2,3-triketo-hydrindene hydrate) is a chemical used in the detection of free amino and carboxyl groups in proteins and peptides. Allergic, immunoglobulin E (IgE)-mediated rhinitis caused by ninhydrin was diagnosed earlier in a 41 yr old woman working as a laboratory technician in a forensic laboratory. Despite handling ninhydrin only in a flow cabinet, symptoms of dyspnoea developed 6 months later. Peak flow was found to vary by 20% during working days. In the specific inhalation challenge it was shown that occupational asthma had also developed due to continuing slight exposure to ninhydrin. The titre of ninhydrin-specific IgE also increased from 0.6 to 1.1 kU x L(-1) in the follow-up. This case stresses the importance of cessation of allergen exposure in occupational allergic rhinitis, in order to prevent asthma.

Occupational asthma caused by triglycidyl isocyanurate (TGIC)

BACKGROUND

Polyester powder paints are extensively used in metal painting. Triglycidyl isocyanurate (TGIC), an epoxy compound, is often used as a hardener. Several cases of allergic eczema from occupational exposure to TGIC have been reported in the literature.

OBJECTIVE

We examined a 36-year-old non-smoking man who worked mainly as a spray painter, using a polyester powder paint containing 4% TGIC. During painting he used protective clothing and a motorized breathing protector. After 4 years he developed eczema on his hands, face and body, and an occupational allergic eczema caused by TGIC was diagnosed. He also suffered from powder-paint-related asthmatic symptoms.

METHODS

Occupational asthma was diagnosed in accordance with the accepted guidelines. Inhalation challenge tests were performed with the paint and TGIC.

RESULTS

Spirometry showed slight obstruction; the blood eosinophils and serum IgE value were elevated. Skin-prick tests with common environmental allergens were negative. The challenge test with lactose powder was also negative. A challenge test with a paint containing TGIC (4%) induced a dual reaction in PEF and a late 23% fall in FEV1. A test with TGIC (4%) mixed with lactose induced a dual PEF reaction, and also dual changes in spirometry. The PD15 in the histamine challenge test decreased significantly after the challenge tests.

CONCLUSIONS

To our knowledge this is the first diagnosed case of occupational asthma caused by TGIC. This case report emphasizes the importance of protecting both the skin and respiratory tract of workers against chemicals such as TGIC, capable of causing skin and respiratory allergy.

Allergic alveolitis following exposure to epoxy polyester powder paint containing low amounts (<1%) of acid anhydrides

Only one case report concerning allergic alveolitis caused by polyester powder paint has been published previously. The aim of this study was to determine whether phthalic anhydride (PA) or trimellitic anhydride (TMA) is the alveolitis-causing agent in such paint. A 61 year old woman showed recurrent symptoms of chills, cough, and fever whilst at work. She was working in a plant where epoxy polyester powder paints were used to paint metal. The paint was found to contain low (<1%) amounts of TMA and PA. The patient showed shadowing on chest radiographs. In bronchoalveolar lavage, lymphocytosis (67%) and a low T-helper/T-suppressor ratio (0.2) were found. Transfer factor was within normal limits, but a slight reduction was verified after re-exposure to the paint. The symptoms, exposure, reduction in transfer factor, findings on chest radiographs and bronchoalveolar lavage were consistent with allergic alveolitis. In conclusion, the polyester powder paint used in the plant caused allergic alve olitis in this patient. Of the constituents in the paint, trimellitic anhydride and phthalic anhydride were the possible causative agents.

Pocket-sized spirometer for monitoring bronchial challenge procedures

Diagnosis of occupational asthma is verified by inhalation challenge testing when frequent monitoring of peak expiratory flow (PEF) or forced expiratory volume in 1 s (FEV1) is needed. FEV1 measurements also allow frequent monitoring of changes in small airways. For the follow-up of lung function of suspected occupational asthma, a reliable, personal and mobile device is needed. We studied the accuracy of a pocket-sized spirometer, Micro Plus Spirometer (MP), compared with our former combination of two devices, i.e. the values of forced expiratory volume in 1 s (FEV1) with those measured with the Vitalograph bellow spirometer (V); and the peak expiratory flow (PEF) values with the values obtained with a Wright PEF meter (W). In healthy control subjects, the values of FEV1 obtained with Micro Plus correspond well to those obtained using a bellow spirometer (R = 0.97) and the mean difference (MP-V) was -0.06 1 irrespective of the mean FEV1 value. W gives smaller PEF values than the MP; the mean difference in PEF (MP-W) was 44 1 min-1, but the values increased linearly with increasing flow. The poor relation between PEF values might be based on the low reliability of the Wright device. In patient follow-up, the FEV1 values measured with MP and V showed a good correlation (R = 0.99). The PEF values in patients increase linearly measured with W vs. MP with increasing flow values. In conclusion, we found the pocket-sized spirometer a handy and useful device for monitoring bronchial challenge procedures in patients with suspected occupational asthma. The number of exhalations during the challenge test follow-up is lessened when FEV1 and peak expiratory flow (PEF) can be measured simultaneously.

Averaged and time-gated spectral analysis of respiratory sounds. Repeatability of spectral parameters in healthy men and in patients with fibrosing alveolitis

STUDY OBJECTIVE

To obtain a basis for assessment of changes in breath sound spectra in patients with pulmonary diseases, short-term and day-to-day repeatability of spectral parameters was studied.

DESIGN

Breath sounds were recorded simultaneously from the trachea and from the chest twice at an interval of 15 min (short-term repeatability) and of 1 to 3 days (day-to-day repeatability). During recordings, air flow at the mouth was controlled, the target inspiratory and expiratory peak flow being 1.25 L/s. Inspiratory and expiratory breath sound spectra were averaged over 7 to 10 successive respiratory cycles. The repeatability of sound intensity (RMS), frequency of maximum intensity (Fmax), and median frequency (F50) was analyzed with analysis of variance.

PARTICIPANTS

Short-term repeatability was studied in 10 healthy nonsmoking men (age 25 to 44 years), and day-to-day repeatability was studied in 10 healthy nonsmoking men (age 23 to 41 years) and in 12 patients with clinically stable fibrosing alveolitis (age 35 to 82 years).

RESULTS

Short-term coefficient of variation (CoV) of Fmax and F50 was 2.6 to 6.7% when recorded from the chest, and 6.2 to 8.7% when recorded from the trachea. Day-to-day CoV of Fmax and F50 in healthy subjects was 4.7 to 8.5% and 5.0 to 8.7% recorded from the chest or from the trachea, respectively. Inspiratory day-to-day variation in those parameters was higher in patients with fibrosing alveolitis. CoV of RMS was high, ranging from 18 to 47% in different subject groups and sampling situations.

CONCLUSIONS

Repeatability of F50 of averaged flow-controlled lung sound spectra is good both in healthy subjects and in patients with fibrosing alveolitis. Thus, F50 of respiratory sound spectra may be useful in monitoring of changes induced by respiratory diseases and interventions. These results emphasize the importance of standardization of recording conditions and of analyzing techniques.

Separation of pulmonary disorders with two-dimensional discriminant analysis of crackles

Previous studies have indicated that disorders producing crackling lung sounds may be different in terms of the waveform of the crackles or their timing in a respiratory cycle. In this study, we evaluated whether two-dimensional discriminant analysis of crackles has a better ability to separate pulmonary disorders than does a single-dimensional analysis. Cracking sounds of patients with cryptogenic fibrosing alveolitis (n = 10), bronchiectasis (n = 10), COPD (n = 10), heart failure (n = 10) and acute pneumonia (n = 11) and of those recovering from pneumonia (n = 9) have been studied. Variables indicating the timing of crackles during inspiration (beginning and endpoint of crackling) and their waveform (initial deflection width (IDW), two cycle duration (2CD) and largest deflection width (LDW)), were used for the analysis. The discrimination properties of one- and two-dimensional analyses with these variables were compared. The two-dimensional distances between the patient groups were the largest by combining IDW and the end-point of crackling. Cryptogenic fibrosing alveolitis was distinguished from bronchiectasis, COPD, heart failure and acute pneumonia without overlap. The differences between the diseases were illustrated two-dimensionally with ellipses. The two-dimensional analysis resulted in better separation between the groups than the use of single characteristics alone. This type of analysis can enhance the diagnostic power of acoustic pulmonary studies. It is also an informative visual way to find differences among pulmonary disorders.

Crackles: recording, analysis and clinical significance

Crackles are short interrupted breath sounds usually associated with pulmonary disorders. According to present opinion, a crackle is generated when an abnormally closed airway opens during inspiration or closes at the end of expiration. The timing of crackles in breathing cycles can be assessed with phonopneumography, their duration with time-expanded waveform analysis, and their pitch with analysis of frequency spectra. The timing, pitch and waveform of crackles are different in pulmonary disorders reflecting different pulmonary pathophysiology. This review deals with the genesis, auscultation, recording and analysis of crackles, with an emphasis on modern signal-processing methods.

Objective assessment of cough

Cough is a primitive reflex typically consisting of an initiating deep inspiration, glottal closure, and an explosive expiration accompanied by a sound. The flow characteristics of cough have been shown to differ between different pulmonary diseases. Cough sounds are generated at the larynx and in the lungs. Modern analysing techniques have also been applied in cough sound studies, and differences in cough sound duration and spectra have been found in pulmonary diseases with different bronchopulmonary pathophysiology. Since the objective assessment of cough is clinically important, automatic cough detectors and counters have been constructed, e.g. to assess the efficacy of antitussive drugs. Also, ambulatory methods for assessment of cough have been reported. This review includes a brief history of cough research and present methods available for objective assessment of cough.

Occupational asthma caused by decorative flowers: review and case reports

Occupational respiratory symptoms caused by decorative flowers are seldom reported in the literature. In the years 1985-1993 four such cases of occupational asthma were diagnosed at the Institute of Occupational Health of Finland. Occupational asthma was caused by freesias (n = 1), chrysanthemums (n = 1), and tulips (n = 2). The diagnoses were based on work-related respiratory symptoms during flower handling in the patients' histories, specific challenge tests, and allergologic examinations. Flower allergy is rare but can even develop into occupational asthma. It usually leads to a change of profession.

Changes in frequency spectra of breath sounds during histamine challenge test in adult asthmatics and healthy control subjects

Air-flow standardized breath sounds were recorded at the chest and at the trachea during histamine challenge test and after subsequent bronchodilation in 12 asthmatics and 6 healthy controls for spectral analysis, to be compared with simultaneous changes in spirometric variables. Of all the lung sound variables measured, the changes in median frequency of the power spectrum (F50) of tracheal expiratory sounds were found to correlate best (r = 0.853, p < 0.0001) with changes in FEV1. The increase of F50 during histamine challenge was significantly larger in asthmatics than in healthy control subjects (p < 0.005). The provocative dose of histamine inducing a decrease of 15 percent in FEV1 (PD15FEV1) and the provocative dose causing an increase of 30 percent in tracheal expiratory F50 (PD30F50) were significantly related (r = 0.754, p = 0.012). In asthmatics, the breath sound frequency distribution in terms of median frequency reflected acute changes in airways obstruction with high sensitivity and specificity. The present method for breath sound analysis can be applied for patients with limited cooperation during bronchial challenge tests.

Changes in crackle characteristics during the clinical course of pneumonia

Recorded crackling lung sounds of 11 patients with pneumonia were studied with phonopneumography, FFT spectrography and time-expanded waveform display. The sounds were recorded on average six days after the onset of pneumonia and the recording was repeated two to four days later. In the first recording the crackles were coarse and midinspiratory. The patients with unilateral pneumonia had a significant difference in the upper frequency limit of inspiratory sound of the FFT spectrum between the healthy and diseased lung (p less than 0.01). In the second recording, the beginning of crackling had shifted later (p less than 0.01) and the end point of crackling also became later (p less than 0.05). The largest deflection width of the individual crackles became shorter (p less than 0.05). The results indicate that the pneumonic crackles vary markedly during the clinical course of pneumonia. The duration of the individual crackles became shorter and the timing of the crackles shifted toward the end of inspiration.

Original waveform of lung sound crackles: a case study of the effect of high-pass filtration

In lung sound research, low-frequency noise usually disturbs the sound signal being recorded. Some researchers therefore use high-pass filtration before the final analysis. In this study, the effect of digital and analog high-pass filtration on the morphology of the lung sound crackles is evaluated. The original nonprefiltered crackle waveform is presented, and the effect of the high-pass filtration on the crackle waveform characteristics is elucidated in one patient with silicoasbestosis.

Validated method for automatic detection of lung sound crackles

Crackling lung sounds are associated with many pulmonary diseases. Their occurrence reflects the quality and the severity of the disease. An automatic method for crackle detection is developed, based on analysing the spectral stationarity of the lung sound. The method is validated by studying the crackles of 20 adult patients; 10 with fibrosing alveolitis (FA) and 10 with bronchiectasis (BE). The number of crackles detected by the automatic method in inspiratory cycles is compared to the number of crackles counted from time-expanded waveforms by two expert observers. The total number of inspiratory cycles studied is 117 and that of crackles 1064. The method has a sensitivity of 89 per cent and a positive predictivity of 88 per cent for patients with FA, and 80 per cent and 83 per cent respectively, for patients with BE. The linear correlation coefficients between the numbers of crackles counted by the automatic method and by the observers is 0.86 (p less than 0.001) for the patients with FA and 0.93 (p less than 0.001) for the patients with BE. The values refer to whole inspiratory cycles. The new automatic method seems reliable enough for clinical and scientific purposes. It enables a rapid and objective analysis of large materials with crackling lung sounds.

Crackles in patients with fibrosing alveolitis, bronchiectasis, COPD, and heart failure

We have studied the crackling lung sounds of ten patients with cryptogenic fibrosing alveolitis, ten with bronchiectasis, ten with chronic obstructive pulmonary disease, and ten with heart failure by analyzing frequency, waveform, and timing of crackles. The upper frequency limit of inspiratory sounds was higher in CFA than in COPD or in HF. The period of crackling was shorter in COPD than in CFA or BE. Inspiratory crackling terminated significantly earlier in COPD than in CFA, BE, or HF. The initial deflection width and the two-cycle duration of the expanded waveforms of crackles were smaller in CFA than in BE, COPD, or HF. The largest deflection width was smaller in CFA than in BE, HF, or COPD and smaller in BE than in HF. The results indicate that crackling lung sounds in different diseases have distinctive features and that their analysis can be of diagnostic value.

Beneficial effects of erythropoietin on haematological parameters, aerobic capacity, and body fluid composition in patients on haemodialysis

Eleven patients on haemodialysis were treated with erythropoietin (EPO), 50-200 U kg-1 once to three times a week, for up to 1 year. After outset of EPO all patients became transfusion-independent. Four patients did not reach the target haemoglobin (Hb) level 100 g l-1 in 5 months. These patients had higher serum concentrations of aluminium (225 +/- 87 micrograms l-1, mean +/- SD) than the responding patients (55 +/- 56 micrograms l-1). Addition of desferrioxamine to treatment with EPO resulted in a rapid rise in Hb values in these patients. Thus, aluminium may inhibit EPO responsiveness. All patients were iron overloaded. Serum ferritin levels declined in all but one patient with secondary haemochromatosis. In exercise tests the aerobic capacity and oxygen uptake increased during EPO therapy. Peak oxygen consumption (Vo2 peak), oxygen pulse, oxygen uptake at anaerobic threshold (AT) and total work output (W max) increased 19%, 36%, 26% and 24%, respectively. Lean body mass (LBM) increased by 8%. Taken together, all clinical EPO effects measured appeared clinically favourable.

Differences in acoustic and dynamic characteristics of spontaneous cough in pulmonary diseases

The aim of this study was to determine whether the flow dynamics and sound spectra of spontaneous cough show characteristic differences in asthma, acute and chronic bronchitis, TBCS and FPD. During the cough, the air flow from the mouth and the sound from the sternal manubrium were simultaneously recorded. The cough sounds were analyzed spectrographically. Peak expiratory flow during cough was significantly lower in asthma than in TBCS, acute bronchitis or FPD. Duration of the first cough sound was longer in asthma than in FPD, TBCS or chronic bronchitis. The number of additional cough sounds was smaller in asthma than in the other conditions. The highest frequency components of cough sound were lower in asthma than in chronic bronchitis or TBCS. The results indicate that pulmonary diseases differ with respect to acoustic and dynamic characteristics of spontaneous cough. This finding may prove useful in the diagnosis of cough.

Long-term recording and automatic analysis of cough using filtered acoustic signals and movements on static charge sensitive bed

Reliable long-term assessment of cough is necessary in many clinical and scientific settings. A new method for long-term recording and automatic analysis of cough is presented. The method is based on simultaneous recording of two independent signals: high-pass filtered cough sounds and cough-induced fast movements of the body. The acoustic signals are recorded with a dynamic microphone in the acoustic focus of a glass fiber paraboloid mirror. Body movements are recorded with a static charge-sensitive bed located under an ordinary plastic foam mattress. The patient can be studied lying or sitting with no transducers or electrodes attached. A microcomputer is used for sampling of signals, detection of cough, statistical analyses, and on-line printing of results. The method was validated in seven adult patients with a total of 809 spontaneous cough events, using clinical observation as a reference. The sensitivity of the method to detect cough was 99.0 percent, and the positive predictivity was 98.1 percent. The system ignored speaking and snoring. The method provides a convenient means of reliable long-term follow-up of cough in clinical work and research.

Asthma and pregnancy: a prospective study of 198 pregnancies

A study was designed to investigate whether asthma, when carefully managed, is associated with an increased risk of complications in connection with pregnancy. One hundred and eighty one asthmatic women were monitored during 198 pregnancies. Antiasthmatic treatment consisted of inhaled beta 2 adrenergic drugs, beclomethasone, sodium cromoglycate, oral theophylline, and systemic corticosteroids as needed. Postpartum information on asthmatic symptoms and infant feeding was collected by means of a questionnaire. A control group of 198 non-asthmatic pregnant women was matched for age and parity. Atopic women had less severe asthma than non-atopic women. During pregnancy 40% of the patients were managed with the same antiasthmatic medication as before pregnancy; 18% needed less and 42% more medication. Pre-eclampsia occurred more often in asthmatic than control subjects, especially in patients with severe asthma. Hypoglycaemia occurred more often in infants of mothers with severe asthma than in infants of mothers with less severe disease. Theophylline medication at term did not influence labour or delivery. Asthma caused no emergencies during labour. Among the asthmatic subjects 28% of babies were delivered by caesarean section compared with 17% in the control group. There was no difference between asthmatic and control subjects with regard to length of gestation, birth weight, incidence of perinatal deaths, low Apgar scores, neonatal respiratory difficulties, hyperbilirubinaemia, or malformations. It is concluded that severe asthma or systemic corticosteroid treatment (or both) during pregnancy seems to increase the incidence of mild pre-eclampsia in the mother and hypoglycaemia in the infant. The findings suggest that careful supervision of asthma during pregnancy and labour by obstetricians and chest physicians working in close collaboration should prevent most of the serious obstetric and neonatal complications of asthma in pregnancy reported by previous authors.