Asthma and chemical bronchitis in vanadium plant workers.

BACKGROUND: Whether vanadium induces bronchial hyperresponsiveness and asthma in previously normal subjects is unresolved: the two reported series addressing this question both have shortcomings. OBJECTIVE: To determine the cause of cough and breathlessness in vanadium plant workers after variable periods of exposure. DESIGN: Case series of employees presenting with persistent symptoms over a 24-month study period. PATIENTS AND METHODS: Forty of an estimated 1,440 patients were investigated by 1) blood count and serum IgE, 2) intracutaneous allergen skin tests, 3) spirometry, and 4) bronchoprovocation by histamine inhalation or exercise challenge. Exposure was assessed by measurement of 1) ambient V2O5, NH3 and SO2 over 7 days during the 24-month study period, 2) urine vanadium concentration at time of first presentation. RESULTS: Twelve of 40 subjects had bronchial hyperreactivity (BHR), and these were compared to 12 age-matched companion subjects whose BHR was normal. In 10, BHR was diagnosed by histamine inhalation (PC20 0.25-1.82 mg/ml, nl > 8.0 mg/ml), and in six of these the abnormality was severe (PC20 < 0.5 mg/ml). A further two had BHR by exercise challenge (FEV1, 600 ml/30% and 770 ml/18% pre/post exercise). After removal from exposure, 9 of the 12 subjects returned for follow-up 5 to 23 months later. BHR was worse in one, still present although less severe in five, and was no longer found in one subject. Baseline spirometry measurements were normal in seven subjects and only mildly impaired in the remaining five of the 12 subjects with BHR. CONCLUSION: This study provides strong supporting evidence that inhaled V2O5 induces BHR and asthma in subjects previously free of lung disease; the abnormality may persist for up to 23 months following exposure; routine spirometry will not detect affected subjects.

Relationship of CSF pH, O2, and CO2 responses in metabolic acidosis and alkalosis in humans.

The effect of induced metabolic acidosis (48 h of NH4Cl ingestion, BE - 10.6 +/- 1.1) and alkalosis (43 h of NaHCO3- ingestion BE 8.8 +/- 1.6) on arterial and lumber CSF pH, Pco2, and HCO3- and ventilatory responses to CO2 and to hypoxia was assessed in five healthy men. In acidosis lumbar CSF pH rose 0.033 +/- 0.02 (P less than 0.05). In alkalosis CSF pH was unchanged. Ventilatory response lines to CO2 at high O2 were displaced to the left in acidosis (9.0 +/- 1.4 Torr) and to the right in alkalosis (4.5 +/- 1.5 Torr) with no change in slope. The ventilatory response to hypoxia (delta V40) was increased in acidosis (P less than 0.05) and it was decreased in four subjects in alkalosis (P, not significant). We conclude that the altered ventilatory drives of steady-state metabolic imbalance are mediated by peripheral chemoreceptors, and in acidosis the medullary respiratory chemoreceptor drive is decreased.

Progesterone in obese patients with respiratory failure.

Two obese patients with acute respiratory failure are described. Both required mechanical ventilation to reverse the respiratory acidosis. On recovery, the major abnormality was failure of ventilatory response to inhaled carbon dioxide. After oral progesterone (100 mg/day and 20 mg/day, respectively) the slope of the carbon dioxide response line increased from 0,02 to 1,14 I min-1 mmHg-1 and from 0,04 to 1,14 I min-1 mmHg-1, respectively. This was associated with sustained clinical remission in 1 patient.

Comparison of carbuterol and hexoprenaline aerosol in bronchial asthma.

A new beta 2-adrenergic bronchodilator, carbuterol, was compared with hexoprenaline and placebo, by double-blind crossover technique in 10 adult asthmatic patients. Carbuterol 200 microgram was compared with hexoprenaline 200 microgram, corresponding to 2 inhalations from a standard aerosol in each case. The carbuterol effect, in terms of vital capacity and forced expiratory volume in 1 second (FEV1) was significantly longer than that of hexoprenaline. Its effect on airways resistance also appeared to be longer, although this difference was not statistically significant. The difference in duration of action may be due to greater potency of carbuterol, or to a longer elimination half-life of carbuterol. No significant effects on heart rate or blood pressure were noted with either drug.

The diagnostic value of the tine and Mantoux tests in a general hospital.

Tine and Mantoux tuberculin tests were compared in 193 hospitalised White patients with a variety of illnesses. With the Mantoux test 52 (27%) were tuberculin-positive and 19 (9.8%) were positive with the tine test. Had the tine technique alone been used, 33 of 52 tuberculin reactors would have been missed. Additional findings were (i) a 73% positivity for Monilia antigen; (ii) the optimal time for reading the Mantoux tests was on the third, rather than the second day; (iii) tuberculin reactivity was not suppressed by either pyrexia or elevation of the sedimentation rate; and (iv) the use of avian PPD demonstrated very few reactors in this population. It is recommended that the tine test be replaced by the intradermal Mantoux test with stabilised freeze-dried PPD tuberculin supplied in test kits with diluent. This matter should be given high priorty in South African general hospital practice and population surveys.

Carbon dioxide response lines in young adults: the limits of the normal response.

Carbon dioxide responsiveness was determined in 126 normal, young adults. The mean +/- SE slope of the line relating PCO2 to minute volume of ventilation was 2.60 +/- 0.107 liter per min-mm Hg. Although a wide range of responses was noted, 80 percent of the subjects had a value for the slope between 1.5 and 5.0 liter per min - mm Hg, with 16.6 per cent having values lying below and 4 per cent above this range. Women were significantly less responsive than men. Low, but significant, correlations were found between the slope and vital capacity, and between the slope and maximal breathing capacity, but not between the slope and height, weight, age, or smoking habits. Additional findings included an increase in the slope with prolonged rebreathing, possibly due to a peripheral chemoreceptor effect; absence of metabolic acidosis during 4 min of rebreathing; excellent short-term reproducibility of results in 111 subjects; and good longer-term reproducibility in most of 10 subjects retested 9 to 24 months later.