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G Ras

Publications and source records attributed to G Ras.

4 recordsLinked to original sources

Effect of Pseudomonas aeruginosa-derived pyocyanin and 1-hydroxyphenazine on pulmonary mucociliary clearance monitored scintigraphically in the baboon model.

The effect of products of the bacterium Pseudomonas aeruginosa on mucociliary lung clearance has been monitored in vivo in the baboon model by scintigraphy. Clearance was found to be inhibited by both 1-hydroxyphenazine and pyocyanin, and a dose-effect was illustrated by the former. This confirms previous in vitro results as well as results from work on guinea-pigs, and holds good prospects for the use of the baboon model under anesthesia in such investigations.

Aerosols↗

A baboon model for in vivo assessment of mucociliary lung clearance.

A suitable baboon model (Papio ursinus) for assessing inhibitory effects on mucociliary lung clearance was required. Clearance of various dimensions of nebulized particles (99mTc-labelled) was monitored with the animals (n = 6) under either ketamine or pentobarbitone anaesthesia. The best prospect of substantial and reproducible clearance in spite of the inhibition by the anaesthesia were obtained with pentobarbitone, and using nebulized radiolabelled particles of diameter range between 10 and 45 microns, thus avoiding trapping in the non-ciliary alveoli.

Aerosols↗

Effect of bacterial products on neutrophil migration in vitro.

Chronic bronchial inflammation is associated with migration of large numbers of granulocytes into the bronchial tree. A study was designed to find out whether products of bacteria commonly isolated in chronic bronchial infection stimulate neutrophil migration in vitro. Neutrophils from healthy donors were studied by a modified Boyden chamber technique. Bacterial culture filtrates stimulated neutrophil migration over a wide dilution range and the chemotactic activity was heat stable. Culture filtrates derived from Pseudomonas aeruginosa, Streptococcus pneumoniae, and Haemophilus influenzae were significantly chemokinetic and directionally chemotactic, whereas filtrates from Staphylococcus aureus were only chemotactic. Gel filtration of S aureus and P aeruginosa culture filtrates yielded high, medium, and low molecular weight fractions showing chemotactic activity. S pneumoniae and H influenzae yielded fractions with only low molecular weight chemotactic activity. Neutrophil chemotactic responses, occurring in response to all bacterial species tested, appear to represent a defence mechanism by the host. Chemoattractant activity may, however, contribute to bronchial damage mediated by products released from continuously attracted, activated neutrophils.

Bacteria↗

Hypercalcaemia in pregnancy: a case report.

A case of hypercalcaemia in a pregnant patient on substitution therapy for hypoparathyroidism is reported. The clinical picture included transient cerebral disturbances, acute pancreatitis and persistent partial blindness. Calcium metabolism in pregnancy is discussed, and a possible mechanism for the sequence of events is postulated. The relevant literature is reviewed.

Adult↗