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Biomedical subjects

J D Graham

Publications and source records attributed to J D Graham.

At least 91 records · Page 5Linked to original sources

Effects of delta1-trans-tetrahydrocannabinol on mechanical performance of isolated heart muscle preparations.

1 The effects of four concentrations of delta1-trans-tetrahydrocannabinol (delta1-THC) (0.1, 1, 5 and 20 microgram/ml) were compared to that of the vehicle (ethanol, 0.5 microliter/ml) on the mechanical performance of isolated cardiac muscle of the cat and rat. 2 In rat isolated papillary muscles, delta1-THC (20 microgram/ml) caused a decline in mechanical performance (-8% in developed tension and -11% in Vmax) in contrast to the apparent lack of effect of ethanol. 3 All other parameters of mechanical performance studied in both rat and cat papillary muscles were unaffected by delta1-THC when compared with ethanol. 4 It was concluded that delta1-THC in concentrations up to 20 microgram/ml had negligible effect on contractile performance, the time course of contraction or muscle elasticity in rat and cat isolated papillary muscle preparations under the conditions studied.

Animals↗

The National Poisons Information Service and hospital admissions for children--the experience in Wales of the Cardiff Centre.

When inquiries to the Cardiff Centre of the National Poisons Information Service were compared with hospital admissions in the eight health authorities in Wales the findings suggested fewer admissions in the area within which the centre is situated and showed a more extensive use in that area than elsewhere. High inquiry rates were associated with high hospital admission rates when the eight areas were compared. If the service were delegated to area level a more complete community use would result.

Adolescent↗

The uptake of tritiated delta 1-tetrahydrocannabinol by the isolated vas deferens of the rat.

1 Weighed stripped vasa deferentia were incubated in Holman's solution containing (a) [14C]-sorbitol 0.014 mm, (b) [3H]-noradrenaline ([3H]-NA) 12.31 nM, (c) [3H]-tetrahydrocannabinol ([3H]-delta1-THC) 1 mug/ml for 5, 10, 20 and 30 minutes. 2 Tissues were washed, dissolved in Protosol, counted by standard scintillation counting technique and 'drug space' expressed as ct min-1 mg-1 tissue/ct min-l mul-1 bathing fluid. 3 Vasa incubated for 30 min with [14C]-sorbitol were washed for varying lengths of time; 82% clearance had taken place after 2 washes of 5 minutes. 4 The uptake of [3H]-NA was inhibited by the presence of desmethylimipramine (DMI) 10 nM in the bath or by pretreatment of rats with 6-hydroxydopamine (6-OHDA). 5 The uptake of [3H]-delta 1-THC was not inhibited by the presence of DMI. It was reduced but not abolished by 6-OHDA pretreatment.

Animals↗

Bronchodilator effect of delta1-tetrahydrocannabinol administered by aerosol of asthmatic patients.

Ten volunteer inpatient asthmatics in a steady state were given a single inhalation of an aerosol (63 mul) delivered in random order, on each of three consecutive days, in the laboratory of a respiratory unit. Before, and for one hour after treatment the pulse, blood pressure (lying and standing), forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), peak flow rate (PFR), and self-rating mood scales (SRMS) were recorded. Treatments were placebo-ethanol only; delta1-tetrahydrocannabinol (THC) 200 mug in ethanol; or salbutamol 100 mug (Ventolin inhaler), administered double blind. Salbutamol and THC significantly improved ventilatory function. Maximal bronchodilatation was achieved more rapidly with salbutamol, but at 1 hour both drugs were equally effective. No cardiovascular or mood disturbance was detected, and plasma total cannabinoids at 15 minutes were undectable by radioimmunoassay. The mode of action of THC differs from that of sympathomimetic drugs, and it or a derivative may make a suitable adjuvant in the treatment of selected asthmatics.

Albuterol↗

Effects of aging on granulopoietic activity (colony-stimulating factor).

This investigation was undertaken to determine whether there is a decrease of granulopoietic activity in subjects of the geriatric age group. Colony-stimulating factor (CSF) is an alpha glycoprotein which causes proliferation of granulocytes in vitro. A study was made of the variation in the level of CSF with age and the state of health in 78 subjects. They were classified into two groups-young (ages 22-60) and old (ages 70-94). The state of health was classified as normal, acute disease, or chronic disease. The results showed that serum CSF does vary with age and health. The CSF levels were higher in the young than in the old. For both age groups, the CSF levels were elevated in acute disease, and subnormal in chronic disease.

Acute Disease↗

A trial of oral delta-1-(trans)-tetrahydrocannabinol in reversible airways obstruction.

Sixteen patients with proven reversible airways obstruction were admitted to a double-blind study to compare the bronchodilator effects of oral delta-1-(trans)-tetrahydrocannabinol (delta-1-THC) and salbutamol. Measurements of forced vital capacity, forced expired volume in one second, peak expiratory flow rate, and maximum expiratory flow rate at 50 percent vital capacity after 10 mg oral delta-1-THC did not differ significantly from the effect of placebo, whereas increases after salbutamol were significant. Analyses of mood, pulse rate, blood pressure, and electrocardiogram showed no important changes after oral delta-1-THC. In vitro studies with isolated tracheal muscle indicate that the activity of delta-1-THC is 1,000 times less than the equivalent dose of isoprenaline, and the effect of delta-1-THC is not abolished by beta-adrenoreceptor blocking agents. It is concluded that oral delta-1-THC, at a dose of 10 mg, does not produce clinically significant bronchodilatation in patients with reversible airways obstruction.

Administration, Oral↗

The effect of delta1-tetrahydrocannabinol on the release of (3H-(-)-noradrenaline from the isolated vas deferens of the rat.

1 The amount of tritium released upon transmural stimulation of the isolated vas of the rat incubated with [(3)H]-Delta(1)-tetrahydrocannabinol (THC) (2.8 muM) was significantly greater than the non-stimulated overflow.2 There was no difference between non-stimulated overflow and the effect of transmural stimulation of vasa equilibrated with [(14)C]-sorbitol (6.5 mg/ml).3 The difference between non-stimulated and stimulated efflux from vasa equilibrated with [(3)H]-Delta(1)-THC was abolished in rats pretreated for 24 h with 6-hydroxydopamine (250 mg/kg).4 The amount of tritium released upon transmural stimulation of the vas incubated with [(3)H]-noradrenaline (6 muM) was significantly greater than the non-stimulated overflow.5 Delta(1)-THC (560 nM and 14 muM) caused a significant dose-dependent reduction of both non-stimulated and stimulated tritium efflux, especially the latter.

Animals↗

The effect of delta1-tetrahydrocannabinol on the uptake of [3H]-(minus)-noradrenaline by the isolated perfused heart of the rat.

Forty-eight isolated rat hearts were perfused with Krebs solution and with [(3)H]-(-)-noradrenaline ([(3)H]-NA) containing 4.5 nCi/ml in 50 ng/ml, as described by Iversen (1963). To groups of six, cocaine was added to [(3)H]-NA in concentrations of 400 nM, 2 and 10 muM. To the rest Tween 80, 25 mug/ml was added to [(3)H]-NA and in three groups Delta(1)-THC additionally in concentrations of 560 nM and 2.8 or 14 muM. Cocaine caused a linear concentration-related inhibition of uptake; Tween caused a 38.7% inhibition; THC caused additionally a linear concentration-related inhibition.

Animals↗