Asbestos bodies in the sputum of asbestos workers: correlation with occupational exposure.

A cross-sectional medical survey including collection of three consecutive sputum samples was carried out among 270 retired workers of a textile and friction materials factory, in order to investigate the relationship between asbestos body identification and asbestos exposure. The individual cumulative asbestos exposure, determined by means of a plant-specific job-exposure matrix based on asbestos air measurements in the workshops, proved to be heavy with a mean cumulative exposure of 217 fibres x mL(-1) x yr. Macrophages and asbestos bodies were identified in sputum samples by light microscopy. The lung origin of the sputum, suggested by the presence of macrophages and/or asbestos bodies, was confirmed in 82.6% of subjects, and 53% of these samples were positive for asbestos bodies. The prevalence of asbestos bodies was not related to sex, smoking status or latency. Conversely, multivariate analysis showed a positive relationship with cumulative exposure, duration and intensity of exposure to asbestos, as well as age and time since retirement. These findings suggest that sputum analysis for asbestos bodies may remain a relevant and noninvasive marker of heavy occupational exposure to asbestos, even years after retirement. Owing to the new perspectives in lung cancer screening, it might contribute to the identification of high-risk subjects.

Mycobacterial infection in an inner city children's hospital.

Childhood tuberculosis is perceived by many as a disease of the past. Experience in a children's hospital serving a deprived population suggested that tuberculosis and other mycobacterial infections were not declining in clinical practice. Fifty three tuberculous and 11 atypical mycobacterial infections were identified between 1978 and 1992. There was no decline in tuberculosis and nine of the 11 atypical infections occurred in the last five years. Altogether 40% of cases of tuberculosis were in non-Asian children; 32% had arrived in the UK or visited family overseas in the previous year; and 38% had a history of tuberculosis contact, usually a close adult relative. Nationally, the previous decline in tuberculosis in all ages has reversed. In the local health districts in London's east end, childhood tuberculosis has also stopped declining and seems to be increasing. It is regrettable that BCG vaccination has been abolished by some districts in the UK, against current recommendations. Childhood tuberculosis is still common in the practice described here, including among children who do not fall into conventionally recognised high risk groups. Inner city dwellers and junior doctors are both highly mobile populations, adding to the risk that paediatricians, particularly those in training, may encounter tuberculosis with little or no previous experience of the condition.

Effect of verapamil on polycythaemia secondary to hypoxia in rats.

1. Polycythaemia occurs in man secondary to chronic hypoxaemia, and may lead to morbidity from hyperviscosity of the blood. Hypoxaemic rats develop similar changes. We have investigated the effect of the calcium antagonist verapamil upon the polycythaemic response to hypoxia in rats. 2. Control groups of 10 male rats breathed air in an environmental chamber for 28 days. Hypoxic groups breathed a normobaric atmosphere of 10% oxygen for 6 h each day, and air for the remaining 18 h. Control and hypoxic groups were treated with intraperitoneal or subcutaneous water, or with intraperitoneal or subcutaneous water plus verapamil. 3. On day 28, packed cell volume (PCV) was measured by a microhaematocrit technique and red cell mass (RCM) by dilution of injected 51Cr-labelled rat erythrocytes. 4. PCV and RCM were significantly higher in all the hypoxic groups compared with the control groups (P less than 0.01 in each case). 5. PCV and RCM were significantly lower in the hypoxic groups treated with intraperitoneal or subcutaneous verapamil than in the hypoxic groups treated with intraperitoneal or subcutaneous water (P less than 0.01). There were no significant differences between PCV and RCM in verapamil- and water-treated normoxic control groups. Verapamil had no effect on the shift of the oxygen/haemoglobin dissociation curve produced by hypoxia. 6. Verapamil reduces the polycythaemic response to repeated intermittent hypoxia in rats. Venesection is usually performed for excessive secondary polycythaemia in man. Our results suggest a possible therapeutic role for verapamil in such individuals.

Intermittent hypoxia in patients with unexplained polycythaemia.

The aetiology of polycythaemia is unclear in up to 30% of patients. Twenty patients with unexplained polycythaemia were investigated to see whether they had an intermittent hypoxic stimulus to erythropoiesis that was undetected by conventional investigations for hypoxic secondary polycythaemia. Overnight polygraphic sleep studies showed that five patients had prolonged nocturnal hypoxaemia. Their arterial oxygen saturation was below 92%, the level at which appreciable hypoxic stimulation of erythropoiesis occurs, for 26-68% of the time for which they were studied. Considerable evidence is accumulating that intermittent hypoxia is a potent stimulus to erythropoiesis, and clinicians should consider the possibility of nocturnal hypoxia in patients with unexplained polycythaemia. Appropriate investigation will lead to the correct diagnosis of polycythaemia secondary to hypoxia in some cases previously regarded as idiopathic, and treatment may then be planned accordingly.

Right ventricular hypertrophy and polycythaemia in rats after intermittent exposure to hypoxia.

Six groups of 20 male adult rats were maintained in an environmental chamber, each group for a period of 28 days. One group breathed air throughout its experimental period, and a second group breathed a normobaric atmosphere of 12% oxygen. The other four groups were exposed to this hypoxic atmosphere for only a proportion of each 24 h cycle: 2, 4 and 12 h daily, and eight periods of 30 min daily. After 28 days, measurement was made, in each rat, of right ventricule (RV) weight and of red cell mass (RCM) by using 51Cr-labelled rat erythrocytes. In the normoxic control group, RV weight corrected for log body weight in grams was 63.2 +/- 1 mg/log body wt. and RCM was 2.02 +/- 0.05 ml/100 g body wt. This was significantly less than in the group hypoxic for only 2 h each day for 28 days: RV weight 66.6 +/- 0.8 mg/log body wt. (P less than 0.05) and RCM 2.27 +/- 0.05 ml/100 g body wt. (P less than 0.05). Greater increases compared with control were observed in all the other hypoxic groups. There was no significant difference in the increases in RV weight and RCM produced by daily hypoxia in a 4 h continuous period and daily hypoxia in eight 30 min periods. The possible role of intermittent hypoxia in producing polycythaemia and pulmonary hypertension has been the subject of much speculation. Our results show that intermittent hypoxia is a potent stimulus to erythropoiesis and to pulmonary hypertension, reflected in RV hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

An oxygen conserving nasal cannula.

Oxygen administration via a nasal cannula incorporating a small collapsible reservoir (Oxymizer, Chad Therapeutics Inc, California) was compared with delivery via a standard nasal cannula. Twelve patients with chronic, stable hypoxaemia (arterial oxygen tension less than 60 mm Hg (8.0 kPa)) were studied. Transcutaneous oxygen and carbon dioxide tensions were recorded by skin electrodes and oxygen saturation by ear oximetry. Baseline measurements during the breathing of air were compared with those made during the breathing of oxygen at flow rates of 0.5, 1.0, and 2.0 l/min via each device. Increases in saturation and transcutaneous oxygen tension were significantly greater at each flow rate with the reservoir device than with the conventional cannula. To produce similar improvements in oxygenation the reservoir device required an oxygen flow rate about half that of the conventional cannula. Use of the reservoir device may reduce the inconvenience and perhaps the cost of supplying domiciliary oxygen, and prolong the time during which patients may rely on a portable cylinder.

[Severe Chlamydia psittaci pneumopathy in an adult]. / Pneumopathie grave à Chlamydia psittaci chez l'adulte.

A previously well 56 year-old woman presented with an adult respiratory distress syndrome which worsened under penicillin treatment, responding only to erythromycin and rifampicin, as well as CPAP ventilation. Diagnostic serology was positive to Chlamydia psittaci. Psittacosis is not a frequent cause of primary extensive pneumonia in intensive care units; other diseases should be looked for in the presence of these non-specific clinical and biological pictures (Legionella pneumophila, Mycoplasma pneumoniae, Streptococcus pneumoniae). Pneumocystis should also be looked for in a typical pneumonia; erythromycin is the antibiotic of first choice in the treatment of primary extensive pneumonia.

[penetration of fosfomycin into bronchial secretions]. / Etude de la pénétration de la fosfomycine dans les sécrétions bronchiques.

The objective of this study was to evaluate the penetration of fosfomycin in bronchial secretions in 11 tracheostomized patients which allowed sampling at successive times, following intravenous injection of 4 gr of the drug during 4 hours. In simultaneous samples of serum and bronchial secretions, the measurement of fosfomycin was performed according to the agar diffusion microbiological method. The results of the study showed a worthwhile penetration of fosfomycin, with a mean bronchial concentration reaching 13,1 micrograms/ml, half an hour after the end of the injection, decreasing slowly with 7,04 micrograms/ml remaining two hours after the injection. The ratio between bronchial levels and corresponding serum levels reached 13% two hours after the injection. Fosfomycin diffusion from serum to bronchial secretions realizes significant amounts that are superior to the MICs of fosfomycin for most bacteria responsible for serious broncho-pulmonary infections in intensive care units.

Microbiology of pyogenic liver abscess.

Sixteen patients with pyogenic liver abscesses were studied over 10 years to discover the causative organisms of the condition. Pus was subjected to Gram-negative smear or gas-liquid chromatography to detect volatile acids characteristic of anaerobes and then cultured. All isolates were identified by conventional methods and tested for sensitivity to appropriate antimicrobial agents. Bacteria were grown from the liver abscesses in all 16 patients. Streptococcus milleri Lancefield group F was the commonest organism isolated from the pyogenic liver abscesses, being found in 13 patients. If Strep milleri is isolated care should be taken not to mistake it for an anaerobe, and finding the organism in the blood should alert the clinician to the possible presence of a liver abscesses.