The synergistic vasoconstrictor effect of Octapressin and catecholamines on the isolated rabbit ear artery.
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Animals↗
Biomedical subjects
D B Frewin
Publications and source records attributed to D B Frewin.
Adverse reactions to radiographic contrast media.
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Adolescent↗
Adverse reactions to drugs: a 12-month hospital survey.
A formalised system of adverse drug reaction (ADR) reporting was instituted at the Royal Adelaide Hospital in August 1975. The present report reviews the results obtained from this system after a 12-month period of operation. A significant number of reports associated with the use of antibiotics and radiographic contrast media were received. The importance of "feed-back" of ADR information to prescribers is emphasised.
Anti-Bacterial Agents↗
Salivary antipyrine kinetics in hepatic and renal disease and in patients on anticonvulsant therapy.
The effects in man of liver disease, renal failure and hepatic microsomal enzyme induction on the elimination kinetics of antipyrine in saliva have been examined. Antipyrine (10 mg/kg) was given orally and assayed in saliva by gas-liquid chromatography. The mean antipyrine half-life from saliva in nine epileptic subjects receiving long term anticonvulsant drug therapy (6 hr +/- 0-9 SEM) was significantly shorter than in twenty normal healthy volunteers (10-7 +/- 0-6). Therapy included phenytoin and phenobarbitone, two drugs known to induce hepatic microsomal enzymes. Five subjects with chronic renal failure exhibited no significant difference in salivary anti-pyrine half-life (11-7 +/- 1-9) compared to the control group, whereas six subjects with chronic liver disease and impaired hepatic function had significantly increased half-life values (42-4 +/- 10). The results suggest that differences in the activity of hepatic microsomal enzymes are reflected by changes in salivary antipyrine elimination kinetics. Chronic renal failure appeared to have no effect on the function of these enzymes.
Adult↗
The effects of commercial local anaesthetic solutions on the isolated rabbit ear artery.
The response of an isolated artery preparation to commercial local anaesthetic solutions containing either prilocaine or lignocaine in the presence of adrenaline or noradrenaline has been examined. In low doses, both local anaesthetics were found to augment the constrictor response to adrenaline, wheras at higher doses the effect of adrenaline was significantly depressed by them. In contrast, noradrenaline's vasoconstrictor response was not potentiated by low doses of lignocaine, although higher dose levels caused a significant reduction in its vasoconstrictor effect.
Anesthetics, Local↗
The effect of storage on the activity of adrenaline in local anaesthetic solutions: an evaluation using bioassay and fluorometric techniques.
The adrenaline content of local anaesthetic solutions has been assessed using a bioassay system and a fluorometric assay method. It was found that exposure of the solutions to daylight for a period of six months greatly reduced their adrenaline content, whereas storage of the same solutions under refrigeration or in the dark reduced the decrease in catecholamine content. Solutions containing adrenaline which were shown in the clinical situation to give inadequate anaesthesia were also tested. The analysis revealed a decline of catecholamine content in each solution.
Animals↗
The effects of etilefrine on blood vessels in the rat tail.
Etilefrine was found to constrict blood vessels in the rat tail through a mechanism which was partly dependent on the sympathetic nerves present in these vessels. The response to the drug was enhanced by pretreagment with noradrenaline and cocaine, and totally abolished by the alpha-receptor antagonist phentolamine. When compared with several other sympathomimetic agents which were tested on the vessel, etilefrine appeared to have a low order of vasoconstrictor activity. These findings would seem to have considerable relevance to the clinical situation where an attempt has been made to use etilefrine in the treatment of patients with orthostatic hypotension.
Animals↗
Plasma dopamine beta hydroxylase activity in affective disorders.
Plasma dopamine beta hydroxylase (DBH) activity was measured in patients with affective disorders and in their relatives. The groups studied had wide distributions of values for plasma DBH activity. No significant difference of plasma DBH activity was found between unipolar and bipolar patients, nor between patients given lithium or placebo. Exercise on a treadmill at 40 degrees or 10 degrees C elicited a different pattern of response for plasma DBH activity in three patients as compared to control subjects. In familial studies we found the values of plasma DBH activity to be almost identical in monozygotic twin pairs and quite similar in dizygotic twin pairs. All pairs, however, were discordant for affective illness. There was also a marked similarity of plasma DBH activity in 15 pairs of the same sex sibs discordant for affective illness. These studies suggest that the resting level of plasma DBH activity is not related to affective illness but is genetically determined.
Adult↗
The effect of local anaesthetics on the vasoconstrictor response of the isolated perfused artery to adrenaline and noradrenaline.
The vascular response to intraluminally and extraluminally administered catecholamines mixed in combination with local anaesthetics has been studied using the isolated perfused rabbit ear artery as the model system. Potentiation of the vascular response to extraluminal adrenaline was observed when prilocaine, lignocaine or cocaine were combined in low concentrations with the vasoconstrictor. No potentiation of the vascular response to extraluminally administered noradrenaline could be demonstrated in the presence of prilocaine or lignocaine. Further, no potentiation to either catecholamine was found if the artery had been denervated or the drugs were applied intraluminally. Possible mechanisms for the potentiation of extraluminally applied adrenaline are discussed.
Anesthetics, Local↗
The effect of ambient temperature on the growth hormone and prolactin response to exercise.
The effect of a standardised exercise procedure on plasma growth hormone (HGH) and prolactin has been assessed in 10 normal human subjects. Each subject was tested in an ambient temperature of 40 degrees and on a subsequent day at a temperature of 10 degrees. At 40 degrees exercise produced an increase in HGH in all 10 subjects, while in the cold only 1 showed a rise in the hormone during exercise. An increase in prolactin with exercise at 40 degrees occurred in some of the subjects, but these changes were small in comparison with those of HGH. Prolactin levels did not increase during exercise in the cold.
Adolescent↗
The effects of 2-phenylalanine 8-lysine vasopressin (octapressin) on blood vessels in the rat tail.
Isolated perfused segments of the ventral rat tail artery have been used in this study to investigate the effects of octapressin on vascular smooth muscle and its interaction with other vasoconstrictor agents. It was found that repeated octapressin administration was associated with tachyphylaxis and that the onset and rate of development of this phenomenon could be modified by cocaine. The constrictor action of catecholamines, electrical stimulation and serotonin on the rat tail artery was potentiated by octapressin. Mechanisms which may be involved in octapressin tachyphylaxis are discussed.
Angiotensin II↗
The influence of adrenergic nerves of the response of blood vessels in the rabbit ear to 2--phenylalanine-8-lysine vasopressin (Octapressin).
The blood vessels in the rabbit ear have been used to investigate the effects of octapressin on vascular smooth muscle. Continuous administration of this drug resulted in tachphlatis. Cocaine enhanced the response of the ear to octapressin; however, this potentiation was not evident when phentolamine was concurrently added to the perfusate. Denervation and reserpinisation of the ear also eliminated the potentiation of octapressin's response by cocaine. The results suggest that there is a small, indirect sympathomimetic component involved in octapressin's action on the vasculature.
Adrenergic Fibers↗
The effect of local anaesthetics on the neural uptake of catecholamines in isolated arteries--a histochemical study.
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Animals↗
Sweating--physiology and pathophysiology.
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Female↗
Clinical and haemodynamic effects of minoxidil in refractory hypertension.
Thirteen patients whose hypertension had been resistant to conventional drug therapy, had minoxidil added to their regimen in doses from 5 to 60 mg/day. All responded with satisfactory reductions of blood pressure to mean values of 149/90mm Hg (supine) and 143/89mm Hg (standing). A significant portion of their previous antihypertensive therapy was either greatly decreased or withdrawn completely. Although fluid retention occurred in most patients as the dose of minoxidil was increased, this could be successfully checked by the use of diuretics. It was considered that in addition to beta-adrenoreceptor blocking drugs to control the reflexly induced cardiac stimulation, sufficiently aggressive diuretic therapy is mandatory to ensure the successful use of this drug. Haemodynamic evaluations in seven patients clearly showed that lowering of blood pressure was the result of decreases in peripheral vascular resistance as significant increases in the cardiac index occurred in all patients.
Adult↗
Sweating responses of normal, paraplegic and anhidrotic subjects.
Dynamic sudomotor response to changing ambient temperatures (30 C to 45 C) was measured on eight unacclimatized subjects including five normals, two paraplegics and one anhidrotic patient. Mean sweating rates, computed from five simultaneously observed local rates, were used to compare the overall sudomotor response to heat exposure of the three groups. In the normal subjects, an average rise of 0.34 C in oral temperature and 2.5 C in mean skin temperature was found in a period of 65 minutes. The paraplegics developed a higher rise in both oral and skin temperatures due to a lower sweating rate in the insentinent region. (Insentient describes the sensory state of the skin below the level of the lesion where the subject has no awareness of surface stimulation). A relatively higher sweating rate was observed on the forehead and the cyclic sweating behavior of the insentient skin was not synchronous with that in the sentient. (Sentient describes the state where partial or total awareness is elicited by stimulation). The anhidrotic patient showed a twofold increase of moisture loss from the skin but no cyclic pattern of sweat gland activity on exposure to heat. In this case, hyperthermia developed with a rise in oral temperature of 1.1 C in 52 minutes versus 0.4 C rise in the controls in a period of 63 minutes.
Body Temperature↗
Adrenergic innervation of human mesenteric blood vessels.
A fluorescent histochemical technique has been applied to study the adrenergic innervation of human superior mesenteric arteries obtained at autopsy. Specific catecholamine fluorescence was demonstrated in the smaller branches of this artery taken from three infants and one child. No specific fluorescence was seen in arteries from three adult subjects.
Age Factors↗
Extensive drug surveillance--a pilot study.
The aim of this Extensive Drug Surveillance programme was to develop a system of drug monitoring suitable for detecting adverse drug reactions in hospitalised patients. The monitored field was a general medical ward in the Royal Adelaide Hospital and monitoring was carried out for a period of one month (September 1974). A total of 85 patients (45 males and 40 females) were monitored and in 14 of them adverse reactions were noted. The overall incidence of such reactions was 16.5%. A greater intake of drugs was a significant finding in patients who experienced adverse reactions. Coupled with this was the observation that patients who stayed longer in hospital had a greater number of drugs administered to them. A third finding was the higher incidence of reactions in female patients.
Drug Prescriptions↗