Activation of alveolar macrophages from children with the acquired immunodeficiency syndrome-related complex

The ability of alveolar macrophages (AM) to release hydrogen peroxide (H2O2), an indicator of AM function, was studied in five children with the acquired immunodeficiency syndrome (AIDS) related complex and, for comparison, in 11 children without disorders of the lung parenchyma. In the AIDS-related complex group, pulmonary manifestations were mild, and lung involvement was suspected by moderate clinical and/or radiological features. None had a past history of opportunistic infections; neither did any have lymphopenia. Cytologic study of the bronchoalveolar lavage (BAL) fluid revealed increased cellularity with increased percentage of lymphocytes. The study of H2O2 release was performed on unstimulated AM and on AM stimulated by phorbol myristate acetate (PMA). Under both experimental conditions, the amount of H2O2 accumulated in the medium was significantly increased in the group with AIDS-related complex (P less than 0.001). As no enhanced oxidative activity has been reported in AM from patients with full-blown AIDS, an increased ability of AM to release oxygen metabolites from children with AIDS-related complex may reflect an initial and temporary step in the course of the LAV/HTLV-III pulmonary disease. Determining AM activation might be a reliable method of assessing the evolution of lung disorder in AIDS.

A controlled study of oxygen metabolite release by alveolar macrophages from children with interstitial lung disease

The ability of alveolar macrophages (AM) to release O2 metabolites was studied in 8 children with interstitial lung disease (ILD), and in 11 children without lung parenchyma disorder. AM were collected by bronchoalveolar lavage. The experiments were performed on unstimulated AM and on AM stimulated by phorbol myristate acetate (PMA) or zymosan. Our results indicated that, with or without triggering agent, the amount of O2 metabolites release was a linear function pattern with time. The accumulation of superoxide anion (O2-) and hydrogen peroxide (H2O2) into the extracellular medium differed depending on the triggering agent used: with PMA, the amount of O2- released was threefold the amount of H2O2 detected in the medium, whereas with zymosan the O2- accumulation was tenfold higher than the amount of H2O2 measured. In patients with ILD, a significant increase in the amount of H2O2 release was observed for both unstimulated and stimulated AM (p less than 0.001). In this group, the measurement was repeated after a 2-month steroid treatment: prednisone had markedly improved the clinical, radiologic, and functional status of the patients, and this improvement was in good correlation with the decrease of O2 metabolite production. The amount of H2O2 release in each case was within the range of control values. Evaluation of O2 metabolite release by AM could be a useful parameter in the assessment of the activity of ILD.

[Allergologic investigation of asthma in infants. Apropos of 153 cases of infants aged 5 to 36 months]

153 asthmatic children from 5 to 36 months (mean age: 26 months) were investigated. The aim of the study was twofold: 1) to determine the reliability and limits of an allergologic diagnosis before 36 months of age; 2) to compare the predictive value of skin-tests with other allergologic tests. Results were expressed according to a score involving 5 parameters derived from the allergologic investigation. Each parameter represented one point: atopic past history, increased level of total IgE antibodies related to the age, presence of blood specific IgE antibodies, blood hypereosinophilia. Infants were considered allergic if their score level was greater than or equal to 3. Concordance between this score level and each parameter was as follows: Positive skin-test 83%; Blood hypereosinophilia 82%; Presence of specific IgE antibodies 80%; Increased level of total IgE 78%; Familial history of atopy 54%. It is concluded that, in allergic infants, a significative link exists between positive skin-test plus the presence of specific IgE antibodies and an atopic disease. However, more children have to be enrolled in a multivariant analysis to assess definitively the predictive value to this score.

Decreased phosphatidyl choline content in bronchoalveolar lavage fluids of children with bronchopulmonary dysplasia: a preliminary investigation

Bronchoalveolar lavage (BAL) was performed on 12 infants who had recovered from neonatal acute respiratory failure and on 12 patients with bronchopulmonary dysplasia (BPD) in order to evaluate the concentration of phosphatidyl choline (PC) in BAL fluid. These two groups were similar at birth (mean birth weight: 1,980 and 1,750 g, respectively; mean gestational age: 33.4 and 32.1 weeks respectively). Mechanical ventilation based on oxygen requirement lasted longer in the group with BPD. BAL was performed at the end of the first year of life (at 8.5 and 10.3 months, respectively) and the results were compared to control values (from infants of the same age without neonatal disease). Whereas the protein concentration in BAL fluid was similar in the two groups, a dramatic decrease of the BAL PC was found in BPD: The mean values of BAL-PC over protein ratio were 0.9 in the group without pulmonary sequelae and 0.3 in the group with BPD. These preliminary results suggest an impairment of the pulmonary surfactant metabolism in this chronic lung disease following neonatal acute respiratory failure.

Inspiratory force reserve of the respiratory muscles in children with chronic obstructive pulmonary disease

The purpose of this study was to evaluate inspiratory muscle force reserve in children with chronic obstructive pulmonary disease (COPD). In 15 hyperinflated (FRC/TLC, 65 +/- 0.7%) children, maximal mouth inspiratory static pressure (PImax) at FRC, mouth occlusion pressure (P0.1), tidal volume (VT), inspiratory time (TI), and total duration of the respiratory cycle (Ttot) were all measured. It was found that PImax at FRC was reduced compared with predicted values. However, after lung volume correction, PImax was in the normal range, and P0.1 was higher, TI was shorter, and Ti/Ttot was lower than predicted. The estimated mean inspiratory pressure for breathing at rest (PI) was significantly higher than predicted and was related to total pulmonary resistance (r = 0.74, p less than 0.001). The fraction of PImax developed by the respiratory muscles for breathing at rest (PI/PImax) significantly increased. The higher the PI/PImax ratio, the more the TI/Ttot ratio decreased (r = -0.64, p = 0.01). At rest, our subjects had to develop a mean inspiratory power (W) of as much as 48% (range, 30 to 76%) of the critical W above which fatigue occurs. Thus, even minimal increases in breathing load might expose children with COPD to respiratory muscle fatigue and to respiratory failure.

[Cholesterol pneumopathy in children. Apropos of 3 cases. Possible role of chronic Epstein-Barr virus infection]

Three cases of cholesterol interstitial pneumonia in patients 3, 9 and 10 years of age respectively are reported. All three were born in Island of Reunion. Two were sisters. All had failure to thrive, dyspnea on rest and clubbing. Respiratory symptoms had appeared early in infancy. Open pulmonary biopsy was diagnostic. Prognosis was poor the boy dying at 4 years of age and severe respiratory insufficiency at 9 or 10 years in the two girls. Current etiological investigations were non contributory. However a profile of chronic infection with Epstein Barr virus (EBV) was found in each case while serological profiles ruled out infection with a virus of the herpes group virus (cytomegalovirus, herpes simplex). The possible role of EBV as an etiological agent of cholesterol pneumonia is discussed and genetic or environmental factors as well.

[Ceftazidime absorption into bronchial secretions in mucoviscidosis patients]

Penetration of ceftazidime into bronchial secretions was studied in 23 patients, of which 18 had cystic fibrosis. Ceftazidime was used as the single drug for treating exacerbations caused by Pseudomonas aeruginosa. Dosage was 6 g/1.73 m2/day divided into three intravenous injections for 14 to 21 days. Bronchial secretion samples were obtained by fiber-optic bronchoscopy or physical therapy. Serum and bronchial secretion ceftazidime concentrations were assayed using a microbiological method. Ceftazidime concentrations in both media were lower in children than in adults : elimination half-life is shorter (1.7 h against 2.45 h in adults), extravascular distribution is faster, with earlier (1 h against 2 h in adults) achievement of the peak bronchial secretion concentration (2 micrograms/ml). The ratio of bronchial secretion concentration to concomitant serum concentration did not exceed 5% at the time of peak bronchial concentration. These results suggest that in cystic fibrosis patients, the faster and lower bronchial penetration of ceftazidime may be due to faster elimination as compared to adults. Although transient elimination of Pseudomonas aeruginosa was achieved in 12 study patients, our findings support the use of higher dosages or alternative administration modalities designed to increase in situ ceftazidime concentrations.

Respiration during sleep in children with COPD

Seventeen children (mean age, nine years) with chronic obstructive pulmonary disease (COPD) were studied during sleep. Electroencephalography, electrooculography, and electromyography were all recorded. Airflow was measured by nasal and oral thermistors, and abdominal and thoracic anteroposterior diameters by magnetometers. Transcutaneous partial pressure of O2 (tcPO2) and of CO2 (tcPCO2) were monitored. The average total sleep time was 283 min +/- 36 (1 SD). Breathing pauses (BP) five seconds or longer were measured. The mean time of BP expressed as a percentage of TST was 1.3 percent +/- 0.8 (1 SD). The BP occurred most frequently during REM sleep. Forty-six percent of BP were obstructive (OBP). The percentage of OBP was significantly related to the degree of lung resistance during wakefulness. Periodic breathing was observed with a mean frequency of 2.2 times per night (range: 0 to 7). Episodes with paradoxic inward rib cage motion were seen one to 29 times (mean 6.6). Drops in tcPCO2 greater than 5 mm Hg occurred one to eight times and 67 percent were observed during REM sleep. Compared to tcPCO2 during W the mean maximal decrease in tcPCO2 was 14 mm Hg (range 8 to 29). tcPCO2 rose with a mean maximal of 9.1 mm Hg (range 6 to 13). It was concluded that children with COPD had worsened gas exchange during sleep.

[Chlamydia trachomatis pneumopathies in infants]

The systematic serological examination of 174 infants aged between 0 and 12 months in a paediatric pneumology unit over a period of 12 months revealed that 59 infants (33%) had antibodies and that at least 15 (8.6%) were infected. Based on the experience gained in this department and on data from the literature, the authors recall the clinical and laboratory features of Chlamydia trachomatis interstitial pneumonia in infants, its treatment, pathophysiology and epidemiology.

[Pneumological aspects of bronchial foreign bodies in children. Experience with 100 cases]

100 cases of bronchial foreign body seen over a period of 4 years represent 1.2% of the admissions of a paediatric pneumology unit; 73% of the children were aged between 6 months and 3 years. The foreign body was vegetable in 61% of cases (a peanut in 44% of cases). The time between the inhalation and the endoscopic diagnosis was greater than 7 days in 70% of cases and greater than 30 days in 37% of cases. Removal of the foreign body was possible in all but one case. In particular, the authors studied the pneumological implications of a foreign body: the value of a quantitative bacteriological study of the bronchial secretions, which was significant in 43% of cases, and detection of the sequelae by prospective clinical and functional surveillance with a follow-up of 3 to 24 months. After 6 months, persistent radiological abnormalities were found in 40% of cases, perfusion disorders were found in 35% and ventilation disorders were found in 64%. A surgical operation was performed in 7 cases: one case of bronchotomy for extraction of the foreign body and 6 cases of parenchymal excision, including 2 total pneumonectomy for a destroyed lung. These were no death. The pathophysiology of the complications of functional disorders and of dilatation of the bronchi is discussed in the context of the experience gained from this series.

[Pneumopathies caused by Chlamydia trachomatis in pediatrics]

Chlamydia trachomatis now has an important place in infantile respiratory pathology. In neonates, it is transmitted in utero, which explains one quarter of the cases of interstitial pneumonia seen during the first months of life. In children, the number of carriers of antibodies increases with age and may be more than 40 p. cent by the age of 7 years. The mode of contamination and the pathological significance remain uncertain in this age group. Chlamydia trachomatis can be a cause of pneumonia in immuno-depressed patients. A survey conducted in a Paediatric Respiratory Medicine Unit showed that 22 p. cent of patients were carriers of the antibody and at least 7.8 p. cent were infected.