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Biomedical subjects

M F James

Publications and source records attributed to M F James.

At least 109 records · Page 6Linked to original sources
PubMed1991

The route of prolonged morphine administration affects the pattern of its metabolites in the urine of chronically treated patients.

Differences in the patterns of urinary morphine metabolites were determined in 15 patients after the prolonged administration of morphine via various routes (oral, subcutaneous, intravenous). The possible correlation between metabolite pattern and the route of prolonged morphine administration was investigated. It was established that the concentration ratios of the active metabolite, morphine-6-glucuronide to morphine and its inactive metabolite, morphine-3-glucuronide are significantly (p less than 0.05) higher after prolonged oral morphine treatment than after the systemic administration (subcutaneous or intravenous infusion) of morphine. It may therefore be concluded that patients receiving morphine orally produced significantly greater amounts of its pharmacologically more active metabolite than patients subjected to chronic systemic morphine treatment.

Administration, Oral↗
PubMed1990

Isoflurane but not halothane stimulates neutrophil chemotaxis.

We have studied the effect of isoflurane and halothane on the chemotactic function of elicited rabbit neutrophils in vitro. In comparison with neutrophils not exposed to each volatile agent, isoflurane stimulated (P = 3.5 x 10(-5], but halothane had no effect on the movement of cells towards the chemical attractant, casein.

Animals↗
PubMed1990

Prolonged paralysis following suxamethonium and the use of neostigmine.

A case of prolonged neuromuscular block following the administration of suxamethonium is reported. Three hours after administration of suxamethonium, a well defined, recovering phase II block was demonstrated with a T4:T1 ratio of 0.25, and neostigmine was administered. Although the T4:T1 ratio was improved to 0.9, T1 remained at 25% of control, and significant paralysis persisted which responded to administration of cholinesterase. It is concluded that neuromuscular monitoring cannot reliably predict reversibility in such cases and that, even after 3 h, antagonism of prolonged suxamethonium block should commence with cholinesterase, followed by neostigmine if necessary.

Cholinesterases↗
PubMed1989

Heart block following propofol: a case report.

We report two cases of ventricular arrest with persisting atrial activity in association with propofol anaesthesia. In both cases, anticholinergic agents corrected the arrhythmia. It is recommended that anticholinergic drugs be given routinely when propofol is used in association with vagal stimulants.

Anesthesia, Intravenous↗
PubMed1989

Use of magnesium sulphate in the anaesthetic management of phaeochromocytoma: a review of 17 anaesthetics.

Seventeen anaesthetics are described in 16 patients with phaeochromocytoma in whom magnesium sulphate (MgSO4) was the principal anti-adrenergic agent used. In 15 of the 17 anaesthetics, MgSO4 produced satisfactory control of cardiovascular changes at induction and tracheal intubation, but in four of these additional sodium nitroprusside was required to control the arterial pressure during handling of the tumour. In one pregnant patient undergoing Caesarean section, MgSO4 was ineffective in controlling cardiovascular disturbances because of inadequate serum magnesium concentrations. This patient had a magnesium deficit before operation. In another patient, diagnosis was made during operation and MgSO4 provided satisfactory control of the crisis. Catecholamine release was studied in five patients and MgSO4 was found to reduce catecholamine concentrations from the time of induction until tumour handling.

Adolescent↗
PubMed1989

Alfentanil and propofol infusions for surgery in the burned patient.

We have studied combinations of alfentanil and propofol for total i.v. anaesthesia in 24 severely burned patients. No inhalation agents were used. After a loading dose of alfentanil 100 micrograms kg-1, the intraoperative requirement was 1.24 (SEM 0.7) micrograms kg-1 min-1, and after a propofol induction dose of 2 mg kg-1 the maintenance rate was 100 micrograms kg-1 min-1. Initial hypotension occurred after induction of anaesthesia, but during the operation, cardiovascular variables were stable. After adequate antagonism of neuromuscular block, respiratory depression persisted in three patients when the two agents were discontinued simultaneously; this was not seen when alfentanil was discontinued 15 min before propofol. Quality of recovery was good, and satisfactory postoperative analgesia was present in the majority of patients 2 h after operation. This study indicates that total i.v. anaesthesia with a combination of alfentanil and propofol appears to be satisfactory in burned patients.

Adolescent↗
PubMed1989

Intravenous magnesium sulfate inhibits catecholamine release associated with tracheal intubation.

The effects of pre-treatment with 60 mg/kg body weight magnesium sulfate intravenous on cardiovascular responses and catecholamine release associated with tracheal intubation were measured in 15 normal patients and in 15 saline solution pre-treated controls. Magnesium pre-treatment increased heart rate by 13 +/- 3.9 beats/minute. After intubation, heart rate was unchanged in the magnesium group at 107.3 +/- 3.6 beats/minute but increased in the control group to 120.9 +/- 4.6 beats/minute (P less than 0.05). Systolic blood pressure increased after intubation from 106.8 +/- 3.1 to 121.0 +/- 4.4 mm Hg in patients given magnesium and from 106.4 +/- 3.12 to 145.1 +/- 5.6 mm Hg in the control group (P less than 0.05). Norepinephrine levels increased from 297.3 +/- 20.9 pg/ml to a peak of 532.5 +/- 30.1 pg/ml 2 minutes after intubation in the magnesium group. In controls, norepinephrine levels increased from 273.3 +/- 39.1 mg/ml to 944.6 +/- 68.7 pg/ml (P less than 0.05 for differences between groups). Epinephrine levels were unchanged from baseline after magnesium but in controls increased from 113.9 +/- 19.5 to 279.6 +/- 92.3 pg/ml (P less than 0.05). We conclude that magnesium sulfate attenuates the catecholamine mediated responses after tracheal intubation.

Adult↗
PubMed1988

Endotoxaemia in exhausted runners after a long-distance race.

The extent to which plasma endotoxin concentrations increased was measured in 89 randomly selected exhausted runners who required admission to the medical tent for treatment in the 1986 Comrades Marathon (89,4 km). Eighty-one per cent had concentrations above the upper limit of 0,1 ng/ml ('endotoxaemic'), including 2% above 1 ng/ml (the reported lethal level in humans), and only 19% had normal levels. There was a negative correlation between plasma endotoxin and plasma anti-endotoxin IgG concentration (P less than 0,025). Those runners completing the race in less than 8 hours had a significantly lower average endotoxin value than those taking longer than 8 hours (P less than 0,025). Also 80,6% of runners (58/72) with high plasma endotoxin values reported nausea, vomiting and/or diarrhoea, compared with 17,7% (3/17; P less than 0,001) with low endotoxin values. Elevated plasma endotoxin concentrations of 32 randomly selected endotoxaemic runners had returned to normal 1-3 weeks later, and most of them (25/32) had increased anti-endotoxin IgG concentrations (P less than 0,02). Fifty-nine runners randomly selected in a short run (21,1 km) 3 weeks after the 89,4 km run completed the race without problems and none showed any increase in endotoxin levels. Further studies in this field are warranted, especially the measurement of endotoxin and anti-endotoxin values from commencement of training to full fitness. It is possible that these measurements may prove useful as predictors of an athlete's or combat soldier's performance.

Antitoxins↗
PubMed1988

Use of magnesium sulphate in the anaesthetic management of phaeochromocytoma in pregnancy.

The anaesthetic management of two patients with phaeochromocytoma complicating pregnancy is presented. In one patient, the operative delivery was followed by elective tumour resection at a later stage. Magnesium sulphate was used as an adjunct to all three anaesthetics, with notable success on two occasion. In one of the operative deliveries, it proved impossible to achieve adequate blood levels of magnesium, due to severe pre-existing magnesium deficiency. Hypomagnesaemia is likely to be present in such cases and must be corrected preoperatively. Magnesium sulphate is a useful adjunct to the anaesthetic management of the pregnant patient with a phaeochromocytoma provided that adequate serum levels of magnesium can be established.

Adrenal Gland Neoplasms↗
PubMed1988

Interactions of adrenaline and magnesium on the cardiovascular system of the baboon.

Cardiovascular variables were measured in baboons before and during an adrenaline infusion at 1 microgram/kg/min, and following two bolus injections of either MgSO4 60 mg/kg or saline. Arterial blood pressure (ABP), systemic vascular resistance (SVR), central venous pressure (CVP), pulmonary arterial pressure and pulmonary capillary wedge pressure were all elevated by the adrenaline infusion. Cardiac output (CO), stroke volume (SV) and heart rate were unchanged but multifocal arrhythmias occurred. Mg infusion abolished arrhythmias and markedly increased CO and SV. SVR was reduced below baseline values by Mg, and ABP and CVP returned toward baseline. Saline did not alter adrenaline-induced changes in any way. It is concluded that Mg has powerful antiarrhythmic effects in the presence of catecholamines and, in addition, may have useful alpha-adrenergic antagonist effects.

Animals↗
PubMed1987

Cardiovascular effects of magnesium sulphate in the baboon.

The effect of Mg infusions on cardiovascular function were investigated in 6 adult male chacma baboons over a wide range of serum Mg concentrations. There was a dose-dependent reduction in systemic vascular resistance which correlated well with serum Mg levels (r = -0.67; p less than 0.001), but arterial blood pressure was only moderately affected at serum Mg levels below 5 mmol/l. Heart rate was reduced at serum Mg concentrations above 5 mmol/l. Cardiac output and stroke work were increased at all Mg levels up to 5 mmol/l, and stroke volume increased significantly until the serum Mg level exceeded 7 mmol/l. Central venous pressure and pulmonary capillary wedge pressure were not affected by increasing magnesium levels, and there was no evidence of myocardial depression at any level of serum Mg.

Animals↗
PubMed1987

Autonomic dysfunction in severe tetanus: magnesium sulfate as an adjunct to deep sedation.

We studied the use of continuous iv magnesium (Mg) infusion to control the sympathetic crises in a patient with severe tetanus characterized by pronounced autonomic nervous system instability. Our results suggested that Mg is a useful adjunct to the CNS depressants traditionally used. This therapy controlled the sympathetic crises and also suppressed the release of catecholamines, although Mg infusions alone appeared to be inadequate therapy.

Adult↗
PubMed1986

Tetany and myocardial arrhythmia due to hypomagnesaemia. A case report.

An 11-year-old boy with acute intestinal obstruction presented with tetany, and developed myocardial arrhythmia during anaesthesia. The procedure was abandoned and the patient further investigated. He was found to have hypomagnesaemia and normocalcaemia. Intravenous magnesium sulphate corrected the tetany, and no further arrhythmia occurred during subsequent surgery.

Arrhythmias, Cardiac↗
PubMed1986

Anaesthetic management of Takayasu's arteritis.

A case of type IV Takayasu's arteritis in whom a renal autotransplant was performed is presented. Extensive cardiovascular measurements were made, which enabled the assessment of vascular responsiveness to various anaesthetic manipulations. The management of the condition is discussed and certain recommendations made in light of the experience gained.

Adult↗