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Biomedical subjects

M H Irving

Publications and source records attributed to M H Irving.

At least 91 records · Page 5Linked to original sources
PubMed1979

Spread of steroid-containing foam after intrarectal administration.

The spread of a steroid-containing foam from the rectum was studied in eight normal controls and eight patients with ulcerative colitis proved by biopsy. A standard dose of foam was labelled with technetium-99m adsorbed on to microspheres of Amberlite resin. Immediately after the foam was administered the extent of spread varied considerably, though in no instance did it extend beyond the rectosigmoid. Further scans at 120 and 240 minutes showed no further spread. It is concluded that a steroid-containing foam has a topical effect only on the rectal mucosa.

Administration, Topical↗
PubMed1979

The effect of aspirin on the fibrinolytic activity of gastric juice.

Fibrinolytic activity in the gastric juice of normal subjects has been studied by a double-blind cross-over technique comparing the effect of placebo and pentagastrin against aspirin and pentagastrin. Aspirin effectively produced a gastritis and pure fibrinolytic activity was detected in the gastric juice, but the number of samples showing pure fibrinolytic activity did not differ between the two groups. In both the placebo and the aspirin groups the presence of a protease active at neutral pH and capable of dissolving fibrin is confirmed. Aspirin is unlikely to cause gastric bleeding by increasing local fibrinolytic activity within the stomach. The model, so constructed, is not sensitive enough to be of value in investigating further the role of gastric fibrinolytic activity in gastric haemorrhage.

Adult↗
PubMed1979

Ntau-methylhistidine in human skeletal and smooth muscle proteins.

1. Fifteen pieces of rectus abdominus muscle and fifteen pieces of taenia muscle were removed from patients undergoing various surgical procedures. 2. The muscles were extracted, hydrolysed and the content of Ntau-methylhistidine was measured. 3. The rectus muscles contained 3.13 +/- 0.7 mumols Ntau-methylhistidine/g fat-free dry solid and the taenia muscles 2.4 +/- 0.6 mumols/g fat-free dry solid. There was a statistically significant difference (P less than 0.05) between these values using the Student's unpaired tau test, although this could have been due to contamination of the taenia muscles with connective tissue. 4. The muscle content of Ntau-methylhistidine was at least 40% higher than the only other reported value and therefore the method of calculating muscle protein breakdown based on Ntau-methylhistidine excretion requires revision.

Aged↗
PubMed1979

Fibrinolytic activity in gastric venous blood. A comparison between normal and diseased stomachs.

The fibrinolytic activity of blood draining from the stomachs of patients with gastroduodenal disease has been compared with the fibrinolytic activity of blood in the systemic venous circulation and with the blood draining from normal stomachs. Gastric venous blood from normal and diseased stomachs contains greater amounts of plasminogen activator than simultaneously sampled systemic venous blood. However, gastric venous fibrinolytic activity does not differ between the normal and diseased stomachs and thus indicates that increased gastric venous fibrinolysis is not just a characteristic of the diseased stomach. The studies suggest that stress may cause activation of the fibrinolytic system in gastric venous blood with the release of small amounts of free plasmin. It is postulated that local fibrinolysis may play a part in potentiating gastric hemorrhage.

Blood Cell Count↗
PubMed1979

Effects of adrenergic blockade on plasma catecholamine levels during adrenaline infusion.

Alpha and beta adrenergic blocking drugs were administered, either singly or in combination, prior to a 3hr adrenaline infusion (2 microgram kg body wt-1 min-1)), Animals were premediated with either phenoxybenzamine (1 mg kg body wt-1 min-1). Phenoxybenzamine did not affect circulating adrenaline levels, but propranolol, either alone or in combination with phenoxybenzamine, resulted in a significant reduction in plasma adrenaline levels when compared with the control unblocked situation of adrenaline infusion without premedication. The results provide a possible explanation for the protective effect of combined adrenergic blockade in shock situations.

Animals↗
PubMed1979

The effect of intermittent compression of the calf on the fibrinolytic responses in the blood during a surgical operation.

The fibrinolytic responses in the blood during surgical operation have been studied in two groups of patients during intraoperative intermittent compression of the calf. Fibrinolytic activity did not differ significantly between the groups. The postoperative fibrinolytic shutdown was not prevented by intermittent compression of the calf. It is concluded that, whatever the mechanism by which venous thrombosis is prevented by intermittent compression of the calf, it is not by further stimulation of systemic fibrinolysis.

Dextrans↗
PubMed1978

The effect of elective surgery on 3-methylhistidine excretion.

Elective surgical operation in normally nourished patients is associated with an increase of up to 40 per cent in the urinary excretion of 3-methylhistidine during the first three postoperative days. This increase was statistically significant (P less than 0.01) on the second and third postoperative days. This probably represents a minor degree of increased muscle proteolysis, principally due to the operative trauma. The possible effect of postoperative starvation requires further elucidation.

Adolescent↗
PubMed1977

Alteration in fibrinolytic capacity after operation.

The fibrinolytic response to 20 min of forearm venous occlusion was studied in patients undergoing major and minor operations. Fibrinolytic capacity, which is defined as the increase in fibrinolytic activity resulting from a period of venous occlusion, was significantly reduced on the first postoperative day after major operations, but not after minor operations. Since venous occlusion results in the release of plasminogen activator from the vascular endothelium into the blood, these findings suggest that the reduction in the level of spontaneous fibrinolytic activity after major operations is the result either of exhaustion of the vascular endothelium of plasminogen activator or defective synthesis and release of this enzyme from the endothelium.

Adult↗
PubMed1977

Plasma catecholamine concentrations during operation.

Plasma catecholamines have been measured before, during and after operation in 40 patients undergoing elective major abdominal surgery and in 12 patients during open heart surgery. Plasma concentrations did not increase during abdominal surgery and showed only small increases during cardiopulmonary bypass. It appears that it is not possible to assess individual intra-operative sympatho-adrenal responses to surgical trauma by measurement of plasma catecholamine concentrations because of the efficiency of catecholamine uptake mechanisms.

Abdomen↗
PubMed1977

Effects of adrenoceptor blockade on plasma catecholamine levels during adrenaline infusion.

1. The present experiments investigate the effects of phenoxybenzamine and propranolol, singly and in combination, on plasma catecholamine levels in sheep receiving a three-hour adrenaline infusion. 2. Five groups of five anaesthetized sheep were studied for a period of 3 h each. One group acted as a control and received only a saline (0.9% w/v NaCl solution) infusion. A second group received a constant infusion of adrenaline (2 mug kg body weight-1 min-1). A third group received a similar adrenaline infusion, having been premedicated with phenoxybenzamine (1 mg/kg body weight). A fourth group recieved a similar adrenaline infusion following premedication with (+/-)-propranolol hydrochloride (7 mug/kg body weight). The fifth group received the adrenaline infusion following premedication with both the alpha- and beta-blocker in the above doses. 3. Plasma catecholamines were measured on blood samples taken at seven intervals before during and following the infusion. 4. Control animals receiving only a saline infusion remained physiologically and biochemically stable throughout the experimental period. 5. Adrenaline infusion in animals not receiving adrenoceptor blocking drugs caused a rise in plasma adrenaline levels from a low basal value of 1 mug/litre to a maximum level of 19.8 mug/litre. Animals premedicated with phenoxybenzamine exhibited a similar response. 6. Animals premedicated with propranolol before the infusion of adrenaline did not demonstrate as marked a rise of plasma adrenaline levels as the two previous groups. The maximum mean plasma adrenaline level recorded in this group was 6.88 mug/litre. 7. Animals premedicated with phenoxybenzamine and propranolol before the infusion of adrenaline showed only a small rise in plasma adrenaline levels compared with animals receiving adrenaline infusion alone. The maximum mean plasma adrenaline level in the group was only 3.43 mug/litre. 8. The studies demonstrate that by an unknown mechanism beta-adrenoceptor blockade with (+/-)-propranolol, either alone or in combination with phenoxybenzamine, lowers the plasma adrenaline response evoked by adrenaline infusion.

Animals↗
PubMed1977

Plasma fibrinolytic inhibitors after operation.

The response of the fibrinolytic system to the stress of a surgical operation has been studied in a group of 39 patients. Fibrinolytic activity was stimulated during the operation but depressed during the early postoperative period. This was accompanied by an increase in the level of fibrinolytic inhibitors in the plasma after operation. This increase in fibrinolytic inhibitors was a result of a significant rise in alpha1 antitrypsin; the level of alpha2 macroglobulin fell both during and after the operation.

Adolescent↗
PubMed1976

Changes in the fine structure of venous endothelium in the rabbit following adrenaline infusion.

The fine structure of the endothelium lining the femoral and mesenteric veins in the rabbit was examined following the infusion of concentrations of adrenaline varying from 0.5 to 5.0 mug/kg. Control animals were infused with saline. Vesiculation of the endothelial cells was observed following each infusion of adrenaline, the effect being most marked with the highest dose used. It is suggested that this vesiculation may be associated with the release of antihaemophilic globulin and/or plasminogen activator from the endothelial cells.

Animals↗
PubMed1976

The effect of beta adrenergic blockade upon exercise-induced changes in blood coagulation and fibrinolysis.

Exercise stress is known to stimulate blood coagulation and fibrinolysis possibly as a result of sympatho-adrenal stimulation of the beta adrenergic receptor. In order to test this hypothesis five men exercised on four separate occasions with and without prior beta adrenergic blockade with oxprenolol, propranolol and pindolol. The increase in plasma adrenaline and noradrenaline concentration was much greater during exercise under beta blockade but activation of fibrinolysis was enhanced as well. Factor VIII levels did not change significantly during any of the experiments. These results suggest that the activation of fibrinolysis by exercise is not mediated by the beta adrenergic receptor. The influence of beta adrenergic blockade on the change in factor VIII with exercise was inconclusive.

Adrenergic beta-Antagonists↗
PubMed1976

The adrenergic response to surgery involving cardiopulmonary bypass, as measured by plasma and urinary catecholamine concentrations.

Plasma and urinary catecholamine concentrations have been measured in 13 patients undergoing cardiac surgery involving cardiopulmonary bypass. The large and progressive increase in plasma catecholamines during bypass reported in previous studies has not been confirmed, and this may be a result of improvements in surgical, anaesthetic and perfusion techniques. The interpretation of urinary findings was complicated by the finding of a positive correlation between catecholamine excretion and urine flow-rate. The findings suggest the need to modify current concepts of the adrenergic response to cardiac surgery and bypass, and question the validity of measuring the urinary catecholamine concentration as an index of stress in these circumstances.

Adult↗