Preoperative cimetidine--effects on gastric fluid

A double blind study of 44 patients (24 placebo, 20 cimetidine) was undertaken to determine tha effect of cimetidine on the pH and volume of gastric fluid during anaesthesia. The pH was significantly higher on cimetidine-treated patients than placebo-treated patients at 0, 15, 30 and 45 minutes following intubation. At induction of anaesthesia, mean pH on cimetidine was 4.5 and on placebo mean H was 2.0. Approximately 70% of patients on cimetidine and 20% on placebo recorded a pH above 2.5 during anaesthesia. The reason for a pH recording of less than 2.5 in seven patients on cimetidine could not be ascertained. Mean volume of gastric aspirate was slightly lower in the cimetidine group at 0, 15, 30 and 45 minutes, but the differences were not significant.

Anaesthetic complications requiring intensive care. A five year review

In a five-year period 110 patients were admitted to the intensive therapy unit (ITU) as a result of 'a complication related to anaesthesia'. The nature of the complication and its outcome are analysed. The most common reasons for admission were cardiopulmonary arrest (32), failure to reverse after muscle relaxants (25), airway problems, and various drug reactions. Twelve deaths occurred in the 110 cases studied.

Activation of guinea pig pulmonary adenylate cyclase by prostacyclin

Prostacyclin activates adenylate cyclase of guinea pig lung homogenates. The concentration for half-maximum activation was 20 nM. Kinetic analysis of the increase in enzyme activity suggested a non-cooperative, bimolecular interaction between prostacyclin and a single receptor population. Comparison of the activity of prostacyclin with that of other prostaglandins revealed a rank order of potency: prostacyclin > prostaglandin E1 > prostaglandin E2 > prostaglandin F1 alpha. 6-Oxo-prostaglandin F1 alpha, the stable hydrolysis product of prostacyclin, produced no increase in adenylate cyclase activity. Lungs were dissected before homogenisation, and prostacyclin-sensitive adenylate cyclase was identified at high concentrations in peripheral lung tissue containing small airways, blood vessels and parenchyma. The precise cellular location of these receptors remains obscure, but the probability that they are in the pulmonary vascular bed rather than airway smooth muscle is discussed.

Human lung adrenoreceptors studied by radioligand binding

1. Direct radioligand-binding techniques have been used to characterize and quantify adrenoreceptors in human peripheral lung tissue removed at thoracotomy from ten patients, nine of whom had evidence of obstructive airways disease. 2. [3H]Dihydroalprenolol was used to characterize beta-adrenoreceptor sites and [3H]prazosin to identify alpha-adrenoreceptor sites. Binding of both ligands showed saturability, high affinity, rapid kinetics, reversibility and stereospecificity. The rank order of agonists and antagonists inhibiting specific binding correlated well with known physiological potencies. Specificity of [3H]dihydroalprenolol binding suggested that the population of lung beta-adrenoreceptors is predominantly of the beta 2 subtype.

Spinal anaesthesia for paediatric radiotherapy

Painful radiotherapeutic procedures on lower limbs are susceptible to spinal anaesthesia. This method is shown to be suitable in children when neuroleptanalgesia provides amnesia, an adequate period of patient immobility, and stable cardiovascular and respiratory conditions. The technique is useful in overcoming the problems of anaesthesia in the radiotherapy environment.

Production of 6-oxo-PGF1 alpha by human lung in vivo

The production of 6-oxo-PGF1 alpha, a stable hydrolysis product of prostacyclin (PGI2), by human lung was demonstrated in five adults. The lowest increase in 6-oxo-PGF1 alpha on passage through the lung was noted in a woman on oral contraceptives.

Orientation to visual stimuli and the superior colliculus in the rat

Rats were trained in a six-choice jumping stand apparatus to enter the dark door, and avoid the five bright doors. Rats with bilateral superior collicular lesions were found to be severely impaired in this task, although further experiments showed that they were able to discriminate bright from dark stimuli and could perform correctly if allowed to approach each door in turn. It is suggested that the superior colliculus is important in orientation to visual cues, and there is some evidence that it is involved in orientation to brightness but not visual form cues.