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Biomedical subjects

F R Ellis

Publications and source records attributed to F R Ellis.

At least 73 records · Page 4Linked to original sources
PubMed1988

A single dose pharmacokinetic study of Gastrobid Continus and Maxolon in the perioperative period.

1. A single dose pharmacokinetic comparison of Gastrobid Continus and Maxolon was carried out perioperatively in two groups of 12 gynaecological patients; each group comprised six patients for major surgery and six patients for minor surgery. 2. The areas under the plasma drug concentration-time curves were similar after both preparations. 3. In the minor surgery group after Gastrobid Continus the plasma drug concentration-time curve was wider at half Cmax (P less than 0.01), Cmax was reduced (P less than 0.05) and delayed (median (range) 4 (3-6) vs 2.5 (2-4) h) compared with Maxolon, and the log of the metoclopramide concentration did not have a linear relationship with time from 2-9 h. 4. A flattening of the plasma drug concentration-time curve was the only difference between the two preparations in the major surgery groups. 5. The plasma drug concentration-time curve was wider (P less than 0.05) at at half Cmax in the minor compared with the major surgery groups receiving Gastrobid Continus. 6. Pharmacokinetic parameters were similar for Maxolon in both surgical groups. 7. Sustained release pharmacokinetic characteristics were most pronounced in the minor surgery group which did not receive opiate medication but in which there were more moderately anxious patients prior to induction and in whom anxiety may have delayed gastric emptying.

Adult↗
PubMed1987

Thermoregulation, plasma catecholamine and metabolite levels during submaximal work in individuals susceptible to malignant hyperpyrexia.

Measurements of body temperature, respiratory gas exchange, sweat evaporation rate and circulating levels of catecholamines, lactate, pyruvate, free fatty acids and glucose were made in seven patients susceptible to malignant hyperpyrexia (MHS) and in seven control subjects during 2 h of treadmill walking at 40% of maximum oxygen consumption. These studies took place in an ambient temperature of 22 degrees C. The MHS patients displayed the same thermoregulatory, plasma catecholamine and metabolic responses as the control subjects. The results of the present study suggest that non-competitive, low-intensity, steady-state exercise need not be contraindicated for MHS patients.

Body Temperature Regulation↗
PubMed1986

The work of the Leeds Malignant Hyperpyrexia Unit, 1971-84.

A detailed account of the procedure of muscle biopsy for screening patients suspected of being susceptible to malignant hyperpyrexia is given, together with a review of the results obtained from 1127 patients screened over the last 14 years. The information should help anaesthetists to discuss the investigation fully with probands and other members of their families before referral for further specific investigation.

Adolescent↗
PubMed1986

Effect of glycopyrrolate and atropine on thermoregulation after exercise.

The effects of two anticholinergic drugs on heat production (derived from oxygen consumption), sweating and core and skin temperature were compared with saline placebo in five healthy volunteers, before and after exercise. There were no significant differences between the groups in resting and peak heat production after exercise. Sweat evaporation rate increased after exercise in all cases, but there was individual variation in response to the drugs. Sweat evaporation was greater after saline placebo compared with atropine, but not after glycopyrrolate compared with saline placebo or atropine. In the saline placebo group, increased sweat evaporation following exercise was reflected by an initial fall, in skin temperature. Following anticholinergic drugs, skin temperature increased after exercise without an initial decrease. Core temperature increased following exercise, but there were no significant differences between the anticholinergic drugs and saline placebo. Although clinical doses of anticholinergic drugs, when compared with saline placebo, inhibited sweating after exercise, core temperature was not significantly increased. Therefore it is suggested that non-evaporative heat loss compensated for the reduction in sweating due to anticholinergic drugs.

Adult↗
PubMed1985

Thermoregulatory responses to cooling in patients susceptible to malignant hyperpyrexia.

The influence of 1 h of surface cooling on body temperature, variables which contribute to thermoregulation and selected hormones and metabolites has been investigated in seven patients susceptible to malignant hyperpyrexia (MH) and in seven matched control subjects. Cooling was achieved using a liquid conditioned coverall worn next to the skin. Skin temperature decreased similarly in both groups of subjects. Heat production increased in both groups, with a slightly higher heat production being seen in the MH group. Core temperature increased in both groups of subjects at the start of the cooling period, with a significantly greater increase occurring in the MH group (control: + 0.13 +/- 0.13; MH: + 0.28 +/- 0.10 degrees C, P less than 0.05). There were no significant changes in plasma lactate, or pyruvate concentrations. Plasma glucose concentrations were lower in the control group; after 30 min of cooling plasma glucose was 4.25 +/- 0.37 mmol litre-1 in the control group and 5.34 +/- 0.21 mmol litre-1 in the MH group (P less than 0.05). There were no significant changes in plasma thyroxine or adrenaline concentrations. Plasma noradrenaline increased in both groups of subjects. The increase in plasma noradrenaline of the MH patients was greater than in most of the control subjects.

Adolescent↗
PubMed1984

Suxamethonium spasm. A differential diagnostic conundrum.

Spasm of muscle in association with suxamethonium is not uncommon. As an accepted early sign of malignant hyperpyrexia (MH), patients have been referred for MH screening who have shown only this abnormality. Case histories of 277 probands have been analysed and grouped according to final diagnosis, depending on results of muscle biopsy and in vitro screening. When muscle spasm is induced with suxamethonium, malignant hyperpyrexia must be considered a probable diagnosis.

Diagnosis, Differential↗
PubMed1984

Dantrolene sodium and dystrophia myotonica.

A patient with dystrophia myotonica was given dantrolene sodium to try to provide muscle relaxation during a cholecystectomy. Dantrolene was used as it is accepted that the drug has a place in the control of spasticity and also causes muscle relaxation, whereas conventional muscle relaxants are unable to control myotonia of muscle origin. Dantrolene alone did not provide good enough intubating and operating conditions in this subject. Later studies showed that, after dantrolene, EMG recordings from the patient were not significantly altered, although an impression of a slight increase in the myotonic potentials was gained.

Adult↗
PubMed1983

The control of muscle contracture by the action of dantrolene on the sarcolemma.

Although dantrolene reverses the muscle contracture seen during a malignant hyperpyrexia (MH) crisis, its site of action is not known. It has been inferred from previous work that the major abnormality in MH is in the sarcoplasmic reticulum, and that dantrolene must act on this organelle. In the present study the ability of dantrolene to control drug-induced muscle contraction was tested. The drugs were chosen because their sites of action were known for inducing contracture. Dantrolene had no effect on contractures induced by 2:4 dinitrophenol, exerted only a minor effect on caffeine contractions, but reduced significantly the contracture produced by K+. It is postulated that the major action of dantrolene is on the sarcolemma, which may be the site of the MH abnormality.

Animals↗
PubMed1983

Studies of body temperatures, blood lactate, cortisol and free fatty acid levels during exercise in human subjects susceptible to malignant hyperpyrexia.

Body temperature at a variety of sites (external auditory meatus, rectum, thigh, chest wall, pad of thumb), blood cortisol, lactate and free fatty acid levels and urinary adrenaline, noradrenaline and dopamine excretion were measured in five human subjects susceptible to malignant hyperpyrexia (MHS) and five normal subjects during a period of progressively severe exercise, starting at rest and going up to an exercise intensity producing heart rates in excess of 180 beats/min. In addition, results are reported of a further study of rectal temperature measurements made during a period of mild exercise in a different group of nine MH susceptible and nine nonsusceptible subjects. The results of the progressive exercise study indicated that as the exercise increased in severity, central (external auditory meatal) temperature rose more in the MHS subjects than it did in the controls. Thumb temperature in both groups rose with exercise but in the MHS subjects this rise was significantly delayed compared with the control subjects. It was thought that this was due to a delay in the onset of vasodilatation which usually accompanies high intensities of exercise. Serum free fatty acids and cortisol levels rose more in the MHS subjects than the controls and during the early stages of exercise blood lactate concentrations in the MHS subjects were higher than in the controls group. During mild exercise, rectal temperature in the MHS subjects was lower than in the controls. It was concluded that the pattern of temperature change was evidence of an abnormality of the heat dissipation mechanisms in the MHS subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Plasma and erythrocyte membrane fatty acids in oral contraceptive users.

The fatty acid composition of the plasma choline phosphoglycerides (CPG) and erythrocyte phospholipids were determined in women using oral contraceptive agents and age-matched female controls. Those using oestrogen and progestogen combined preparations had higher concentrations of palmitic acid (16:0) and linoleic acid (18:2 omega 6) and lower concentrations of stearic acid (18:0) and long chain polyunsaturated fatty acids (LCP), in particular arachidonic acid (20:4 omega 6) and eicosapentaenoic acid (20:5 omega 3), in their plasma CPG than controls. These differences were reflected in the erythrocyte phospholipids. The progestogen-only group had similar concentrations to matched controls. It is suggested that the lower concentrations of LCP in combined pill users may affect membrane function and prostaglandin synthesis and may relate to their increased risk of thrombosis.

Adolescent↗