[Development of occupational asthma. Follow-up R.F.E. of 23 cases].

Occupational asthma can either improve or develop into chronic respiratory insufficiency. It is often difficult to predict which course will be followed. Here we report the follow-up of respiratory function of 23 patients with occupational asthma of at least one year's standing, due to various substances; several prognostic factors are discussed.

A tube system for the management of ruptured oesophagus.

In a patient who has ruptured his oesophagus a major objective should be to prevent access of swallowed material or refluxed gastric contents to the area of the rupture. We describe a tube system, introduced into the oesophagus via a cervical oesophagostomy, which prevents swallowed material from getting to the lower oesophagus and allows a tube to the passed into the stomach for continuous aspiration of gastric contents. To discontinue the diversion, a surgical procedure is not required.

Heat-induced changes in respiratory pathways and mitochondrial structure during microcycle conidiation of Neurospora crassa.

Changes in both respiratory pathways and mitochondrial structure of Neurospora crassa occurred under conditions of microcycle conidiation. Upon heat-treatment at 46 degrees C, conidia developed a highly cyanide-insensitive, hydroxamate-sensitive respiration associated with morphological alterations in mitochondrial membranes; such changes were time-dependent. When heat-treated conidia were shifted down to 25 degrees C, the alternate, hydroxamate-sensitive respiration decreased significantly, paralleling the recovery of well-cristated mitochondria with an electron-dense matrix in the germ tubes.

Differential deoxyribonucleic acid synthesis during microcycle conidiation in Neurospora crassa.

In conidia of Neurospora crassa germinating at 25 degrees C, DNA synthesis measured by incorporation of tritiated adenosine reaches a maximum soon after the outgrowth of the germ tube (6--7 h after inoculation). In conidia heat-treated at 46 degrees C (for 15 h), a maximum of incorporation of the DNA precursor occurs already 1 h after inoculation, then the incorporation progressively declines until the end of the heat-shock. When such conidia are shifted to 25 degrees C, a maximum of DNA synthesis occurs during the development of the presumptive conidiophore as at the outgrowth of normal germ tubes.

[Anticonidiogenic effect of hydroxyurea on Neurospora crassa].

Conidiation induced in a low sugar-ammonium medium (or by other means such as full starvation or heat shock) is almost fully prevented by hydroxyurea. In a parallel manner the DNA/RNA and DNA/protein ratios are prevented from increasing.