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Biomedical subjects

J G Collier

Publications and source records attributed to J G Collier.

At least 37 records · Page 2Linked to original sources
PubMed1983

Evidence for an effect of sodium cromoglycate on sensory nerves in man.

Sodium cromoglycate was given by both intravenous injection and local intra-arterial infusion to healthy volunteers. Intravenous injection of a dose of 4 mg in four subjects caused a statistically significant rise in blood pressure and pulse rate associated with a feeling of warmth in the perineum and blush areas of the face and chest. Brachial artery infusion of sodium cromoglycate at doses of 100-1000 microgram/min caused a feeling of warmth in the limb during 26 out of 30 infusions and this sensation was subject to tachyphylaxis. During eight infusions in which there was a sensation of warmth there was no change in local blood flow as measured by strain-gauge plethysmography. In a further six studies involving 12 infusions of sodium cromoglycate the feeling of warmth was not accompanied by a rise in local skin temperature. The results suggest that sodium cromoglycate may stimulate afferent nerves in man.

Adult↗
PubMed1983

The pharmacokinetic assessment of sodium cromoglycate.

The plasma concentration of sodium cromoglycate (SCG) was measured in four healthy subjects by radioimmunoassay after a 4 mg intravenous dose and after inhaling from 20 mg capsules, and from 10 and 30 mg ml-1 nebulizer solutions. The mean absorption constant (K1) after inhalation was 0.43 h-1. The mean elimination constant from the plasma (Kelim) after intravenous administration was 11.5 h-1, and that after inhalation was similar. The apparent volume of distribution of SCG (Vd beta) was 0.2 litre kg-1 and the mean plasma clearance was 0.35 litre h-1kg-1. The amount of SCG absorbed after inhalation varied according to the method of inhalation and dose. After the inhalation of powder from 20 mg capsules, 1.30-3.96 mg reached the plasma, after inhalation of SCG produced by nebulizing a 10 mg ml-1 solution for 5 min at 10 psi using a Minineb nebulizer 0.19-0.31 mg reached the plasma and when the solution was increased to 30 mg ml-1 the figure was 0.33-0.45 mg.

Absorption↗
PubMed1983

The effect of sodium cromoglycate on the development of exercise-induced angina pectoris.

The effect of inhaling sodium cromoglycate on the development of chest pain in 8 patients with exercise-induced angina pectoris was studied in a double-blind cross-over placebo controlled trial. Blood levels of sodium cromoglycate of 24-136 ng/ml did not affect either the time to develop pain on exercise or the rate-pressure product at the time of pain. In view of the original observation that Khellin reduces angina, it is suggested that further studies should be performed to assess the effect of SCG at higher concentrations in the plasma.

Angina Pectoris↗
PubMed1981

Effects of pargyline and SKF-525A on brain N,N-dimethyltryptamine concentrations and hyperactivity in mice.

Mice pretreated with the monoamine oxidase inhibitor pargyline showed a dose-dependent increase in hyperactivity for up to 2 h following injections of N,N-dimethyltryptamine (DMT: 0.5-8.0 mg/kg). Hyperactivity was related to a linear increase in whole brain concentrations of DMT as measured by a new sensitive gas chromatographic assay. The duration of this behaviour paralleled the concentration of DMT in the brain from 15-120 min. However, at 15 min, there was no significant difference in brain DMT concentrations between mice receiving pargyline and those given distilled water at the two dose levels of DMT studied (2.0 and 8.0 mg/kg). Pre-treatment with the microsomal enzyme inhibitor SKF-525A, alone or in combination with pargyline, had no effect on the DMT-induced behaviour or on the brain levels of DMT.

Animals↗
PubMed1980

Investigation of a combined arteriolar dilator and beta-adrenoceptor antagonist (SK & F 92657) in the peripheral vessels of man.

1 SK & F 92657 is a new compound which in animals has both precapillary vasodilator and beta-adrenoceptor blocking activity. The effects of the drug on forearm blood flow and dorsal hand vein distensibility have been studied in healthy volunteers. 2 Forearm blood flow was measured by venous occlusion plethysmography. The drug was infused directly into a brachial artery. The effects of SK & F 92657 on resting flow and on the dose-response relationship for intra-arterial isoprenaline were studied. 3 Venous distensibility was measured in the large veins on the back of the hand. The drug was infused directly into a selected vein and its effects on resting tone and on the responses to noradrenaline and to isoprenaline were investigated. 4 Intra-arterial infusion of SK & F 92657 over 2 min caused a dose-dependent increase in forearm blood flow which developed gradually to reach a maximum after approximately 40 min. Infusion into dorsal hand veins at 100 ng/min and 500 ng/min had no dilator effect in veins preconstricted with noradrenaline. At higher doses SK & F 92657 potentiated the constrictor effect of noradrenaline. 5 In both veins and arteries SK & F 92657 attenuated the dilator effects of isoprenaline. The drug had no effect on the venodilator effects of bradykinin, histamine or sodium nitroprusside. 6 The pattern of response of these vessels to locally infused SK & F 92657 is exactly that expected of a drug combining the properties of hydralazine-like vasodilatation and beta-adrenoceptor blockade. Furthermore, in the arterioles, both properties were manifest at the same dose.

Adrenergic beta-Antagonists↗
PubMed1980

Acquired tolerance to dilator action of hydrallazine during oral administration.

1 The effect on forearm blood flow of local intra-arterial infusion of hydrallazine has been studied in twelve patients with essential hypertension and six normal subjects. 2 When the patients with hypertension were not taking hydrallazine by mouth, they responded to intra-arterial infusions with a dose-dependent increase in forearm blood flow that was not significantly different from that in normal subjects. 3 When the patients were taking hydrallazine by mouth, the increase in forearm flow in response to intra-arterial infusions was reduced and forearm vascular resistance did not fall as low as it did in the control study (P less than 0.01). 4 In four patients, the response to intra-arterial hydrallazine was attenuated to a major extent, and in three of these, there was little or no response to oral treatment. In eight patients, the response to intra-arterial hydrallazine did not fall below one half of that in the control study and this minor reduction in sensitivity might be expected to impair, but not abolish, the response to oral treatment. 5 It is concluded that the resistance vessels commonly develop tolerance to the dilator action of hydrallazine during long-term oral therapy. In some patients a high degree of tolerance develops and this is an important cause of failure to respond to oral treatment.

Administration, Oral↗
PubMed1979

Comparative dilator effect of verapamil and sodium nitroprusside in forearm arterial bed and dorsal hand veins in man: functional differences between vascular smooth muscle in arterioles and veins.

Verapamil and sodium nitroprusside induce a dose dependent dilatation in the forearm arterial bed and preconstricted dorsal hand vein in man. Verapamil is about twenty times more effective in dilating arterioles than veins; sodium nitroprusside is about ten times more effective in veins than arterioles. These differences can be related to functional differences between the two types of vessel.

Adult↗
PubMed1975

Seminal prostaglandins in infertile men.

The concentration of prostaglandin E (PGE) was measured in the semen of 5 men of proven fertility and in 12 men of couples who were infertile but in whom no abnormality had been detected by conventional semen analysis, postcoital test of sperm motility, endometrial biopsy, and laparoscopic dye insufflation of the fallopian tubes. In the fertile men the mean PGE concentration was 52.7 +/- 9.9 mug/ml, and in infertile men the concentration was 22.1 +/- 2.76 mug/ml; the difference between the two groups was highly significant (P less than 0.001). In five of the infertile men attempts were made to raise the PGE concentration by the administration of either corn oil, which contains the prostaglandin precursor linoleic acid, or caffeine, which inhibits prostaglandin degradation; the response to both agents was insignificant.

Caffeine↗
PubMed1975

Plasma renin activity during and after dynamic and static exercise.

The effect of dynamic and static exercise on plasma renin activity was investigated in three normal males. Near maximal supine exercise for 10 min on a bicycle ergometer caused a small increase in plasma renin activity during exertion with a much larger increase during recovery which reached a peak between 10-20 min. Supine exercise at half this level and static exercise (hand-grip) had no detectable effect on plasma renin activity.

Heart Rate↗