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Biomedical subjects

F Ruff

Publications and source records attributed to F Ruff.

At least 37 records · Page 2Linked to original sources
PubMed1979

Influence of immersion to the neck in water on airway closure and distribution of perfusion in man.

We measured closing volume (CV), expiratory reserve volume (ERV) regional distribution of lung volume (Vr) and perfusion in 7 normal subjects in air and during immersion to the neck in water. In four subjects immersion resulted in a CV greater than ERV and the normal perfusion distribution became inverted. In the other subjects, ERV remained larger than CV and perfusion distribution during immersion was uniform, not inverted. In 5 subjects closing volume increased and in 3 of them, the ratio of apical/basal Vr increased significantly during immersion. One subject had nomeasurable CV and in the other it was not measured. The data suggest: (1) that when CV is greater than ERV during immersion there is an inversion of the normal perfusion distribution, caused by hypoxia and/or an increase in mean alveolar pressure in the alveoli beyond the closed airways, and (2) that an increase in pleural pressure gradient during immersion may contribute to the increase in C.V.

Adolescent↗
PubMed1978

The effects of pentobarbitone and urethane on pulmonary airway resistance in guinea-pigs and their interactions with drugs.

1 Propranolol increased pulmonary airway resistance (PAR) in the conscious guinea-pig, whereas atropine had no effect, suggesting the existence of a continual sympathetic bronchodilator tone. 2 The direct bronchoconstrictor effects of histamine, acetylcholine and 5-hydroxytryptamine were modified by autonomic reflexes: a bronchodilator one, abolished by propranolol, and a cholinergic bronchoconstrictor one, seen with histamine. 3 Pentobarbitone increased PAR, an effect which was reduced by propranolol but which was unaffected by atropine. The bronchoconstrictor effects of histamine, acetylcholine and 5-hydroxytryptamine were potentiated by pentobarbitone. 4 Pentobarbitone therefore appears to inhibit the adrenergic bronchodilator tone and to depress adrenergic reflexes, these being the preponderant autonomic influences in these experiments. 5 Like pentobarbitone, urethane increased PAR in the conscious guinea-pig and potentiated the bronchoconstrictor effects of the three amines. These actions are similarly attributed to a reduction in adrenergic influences.

Airway Resistance↗
PubMed1978

[Changes in the activity of histamine-liberating enzymes in acute experimental anaphylaxis].

The authors examined the changes in the histamine level, DAO (diaminoxidase) activity and N--MT (N-methyltransferase) activity in blood (plasma) and tissues of lung and liver (N--MT was examined only in the indicated tissues) in 105 guinea pigs, 45 of whom were healthy and 60 sensibilised and examined during the anaphylactic shock. It was established that during the acute anaphylactic shock there was demonstrative hyperhistanemia and hyperhistaminasemia, which were not observed during experimental anaphylactic shock with subacute course. The activity of lung and liver N--MT in animals with acute and subacute anaphylactic shock did not differ from that of the healthy guinea pigs. The complete inhibition of DAO activity in healthy animals and those with anaphylactic shock did not induce change in the activity of N--MT as well. The latter did not alter after sharp or high level or moderate elevation of the tissue histamine for several days. This histamine was a specific substrate for this enzyme. N--MT is an inductive enzyme, which apparently does not participate in histamine metabolism during acute and subacute anaphylaxis in guinea pigs. For its change, probably, is necessary longer time.

Acute Disease↗
PubMed1976

[Study of prostaglandin synthesis during anaphylactic shock in guinea pigs].

In guinea pigs actively sensitized with ovalbumin and shocked, we have measured blood histamine and histaminase, pulmonary content in cycli AMP and prostaglandins (PG) E1, E2 and F2alpha. In pulmonary efferent blood, both PGE and PGF are increased. In lung tissue, only PGF2alpha, which are bronchoconstructive mediators, are increased. Th increased level in PG seems to have two origins: first a specific increase, then an increased synthesis secondary to histamine release.

Amine Oxidase (Copper-Containing)↗