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Biomedical subjects

F Reynolds

Publications and source records attributed to F Reynolds.

At least 163 records · Page 9Linked to original sources
PubMed1982

Phenytoin-valproate interaction: importance of saliva monitoring in epilepsy.

Sodium valproate is often used with phenytoin when epilepsy cannot be controlled by a single drug. Sodium valproate depresses phenytoin protein binding and so invalidates plasma phenytoin monitoring as a means of determining precise phenytoin dosage requirements. Plasma and saliva phenytoin and plasma valproate concentrations were measured in 42 patients with epilepsy receiving both drugs. Phenytoin protein binding was also measured by ultrafiltration in 19 of these patients and 19 patients taking phenytoin alone. Saliva phenytoin concentration bore the same close correlation to unbound (therapeutically active) phenytoin in patients receiving both drugs as it did in patients receiving phenytoin alone, whereas plasma total phenytoin did not. The same therapeutic range for saliva phenytoin (4-9 mumol/1; 1-2 microgram/ml) was therefore valid in both groups. The depression of phenytoin binding was directly related to the plasma concentration of valproate both in random samples taken from the 42 patients and in samples taken throughout the day in two of these patients. This was confirmed in vitro. Even when the concentration of valproate is known the degree of binding cannot be predicted. Saliva rather than plasma monitoring of phenytoin treatment is therefore valuable in the presence of valproate and with reduced phenytoin binding from any cause.

Adolescent↗
PubMed1982

A controlled trial of extradural fentanyl in labour.

In a double-blind trial carried out on patients in the first stage of labour, either fentanyl 80 micrograms (n = 35) or physiological saline (n = 33) was added to the test dose of bupivacaine and administered extradurally. Thereafter analgesia was maintained as necessary with 0.5% bupivacaine alone. Supplementary bupivacaine (a further dose within 1 h) was required to produce satisfactory analgesia in eight patients in the fentanyl group and in 26 patients in the control group. Analgesia was more rapid in onset and more complete in the fentanyl group, and the duration from first dose to first top-up was 2.36 h, compared with 1.66 h (supplements notwithstanding) in the control group. No serious side-effects were encountered in either group, although eight patients in the fentanyl group experienced mild itching, compared with one in the control group.

Adult↗
PubMed1981

An intradermal study of the local anaesthetic and vascular effects of the isomers of mepivacaine.

The duration of action and vascular effects of L(+) and D(-) and racemic mepivacaine were investigated in a double-blind study in 23 fit volunteers. Isosmolar 0.1-ml intradermal injections of a range of concentrations of each agent from 0.011% to 2.7%, and physiological saline were given in duplicate to at least 14 subjects. Local colour changes were observed 5-10 min after injection, and analgesia to pinprick was tested at 5-min intervals thereafter until full recovery. Both isomers were vasoconstrictor at concentrations of 0.3% and less; at greater concentration the L isomer produced more vasodilation and haemorrhagic change. The duration of action of both isomers increased with concentration between 0.05 and 0.9%, but the L isomer was significantly longer acting than the D at 0.3% and more. The log dose-duration curve could be interpreted as linear between 0.1 and 0.9% with the slope of L isomer being twice as steep as the D. The findings for racemic mepivacaine were between those of the two isomers. The longer duration of analgesia of L-mepivacaine was not associated with superior vasoconstrictor power.

Adult↗
PubMed1979

Ocular and cardiovascular effects of local and systemic pindolol.

Ocular and cardiovascular effects of topical and intravenous pindolol have been studied in a balanced cross-0ver double-blind trial in 6 healthy volunteers. When applied to 1 eye pindolol lowered intraocular pressure in both the treated and untreated eyes with only minimal reduction in resting pupil diameter and light reflex response. The concentration in plasma was much lower and inhibiton of exercise tachycardia about half that when the same dose was administered intravenously. The findings suggest that beta-adrenoceptor blocking drugs should not be used in the treatment of glaucoma in patients who also suffer from heart failure.

Adult↗
PubMed1978

Processing of the 5' end of Escherichia coli 16S ribosomal RNA.

We have isolated and partially characterized an endonuclease involved in processing the 5' end of 16S rRNA of Escherichia coli. A mutant strain that is deficient in this enzyme accumulates a new precursor of 16S rRNA, named 16.3S rRNA. This rRNA has the 3' end of mature 16S rRNA but is about 60 nucleotides longer at the 5' end. In vitro, the enzyme preparation cleaves an RNA fragment of about 60 nucleotides from the 5' end of 16.3S rRNA in 30S ribosomal subunits, yielding the mature 5' end of 16S rRNA. In the mutant strain the 16.3S rRNA is associated with a full complement of 21 ribosomal proteins in 30S subunits. These particles, which comprise 50% of the total 30S subunits, are present on polyribosomes.

Escherichia coli↗
PubMed1978

An intradermal study of the local anaesthetic and vascular effects of the isomers of bupivacaine.

1 L(-)- and D(+)-bupivacaine in eight different concentrations from 0.06 to 7.69 mmol/l (0.002--0.25%) and physiological saline were given intradermally to seventeen volunteers, using a double-blind technique. 2 Local colour changes were observed as 'nil', 'pink' or 'pale' and analgesia to pinprick was assessed every 10 min to give an estimate of apparent in vivo potency and duration of action (50% recovery). 3 Both isomers were vasodilator in all cases at 7.69 mmol/l, but the incidence of vasodilatation waned with decreasing concentration, more rapidly with L(-)-than with D(+)-bupivacaine. 4 Only L(-)-bupivacaine showed a vasoconstrictor effect. This was maximal at a concentration of 0.48 mmol/l, when the incidence of pallor was 92%. 5 L(-)-bupivacaine had a longer duration of analgesic action than the (D+)-isomer from 0.48-3.84 mmol/l; this was reflected in a higher apparent in vivo potency.

Adult↗
PubMed1978

[Grave robbing].

Explore the source record for details and available documents.

Anatomy↗
PubMed1977

People who deliberately poison or injure themselves: their problems and their contacts with helping agencies.

A representative sample of 130 people was interviewed shortly following self-poisoning or self-injury. The interview method is described. Events in the week prior to the attempt, and the incidence of various kinds of chronic problems are reported. Events involving key relationships were much more common than other kinds. The most important event was a quarrel, particularly in the 48 hours prior to the attempts and more common with female than with male attempters. The possible relevance of quarrels to understanding overdose behaviour is discussed. Nearly a third were receiving non-psychiatric treatment at the time of the 'attempt'. Approximately one quarter were currently receiving psychiatric treatment and a half had received it at some time. A substantial proportion had been admitted to either psychiatric or non-psychiatric hospitals within the past year. The proportions indicating the need for various kinds of help are reported. Most people said they needed 'someone to talk to'. More than half had been in contact with some form of helping agency during the week prior to the attempt. The possible significance of these findings is discussed. An attempt was made to look for 'syndromes' or groupings of problems. The resulting analysis, whilst of interest, did not lead to a satisfactory method for classifying individuals. It was concluded that a more satisfactory typology of 'attempters' is likely if types of relationship problems are investigated in more detail.

Adolescent↗
PubMed1976

Salivary phenytoin concentrations in epilepsy and in chronic renal failure.

Plasma total, plasma unbound (free, therapeutically active), and salivary phenytoin concentrations have been measured in seventeen epileptics and in seven patients with chronic renal failure on long-term phenytoin therapy. Patients with chronic renal failure had low plasma total, but disproportionately high plasma free, drug concentrations indicating impaired protein binding. Even so, their plasma free drug concentrations never fell within the predicted therapeutic range on conventional phenytoin dosage. Salivary drug concentrations correlated closely with plasma free drug concentrations. These observations suggest that phenytoin therapy could be more appropriately monitored by measurement of salivary, rather than plasma, drug concentrations. Avoidance of blood-sampling would be an added advantage, particularly in children and in uraemia. The present results suggest that the optimal therapeutic range of salivary phenytoin would be 4-10 mumol/1.

Adolescent↗
PubMed1976

Logical approach to lignocaine therapy.

Plasma lignocaine concentrations were measured during and after lignocaine infusions administered for suppressing ventricular dysrhythmias. Twenty-four patients with a primary diagnosis of acute myocardial infarction without gross circulatory disturbance received, after a bolus of lignocaine, either 4 mg/min for 30 minutes, 2 mg/min for two hours, then 1 mg/min thereafter or 1 mg/min throughout. The higher dose regimen produced continous therapeutic levels of lignocaine, which were achieved only after four hours by the lower dose. On the other hand, in patients who had undergone cardiac surgery and who had circulatory and heptic dysfunction the lower dose regimen achieved therapeutic levels early. The plasma half life was longer in the surgical group (P less than 0.02). The higher initial infusion rate is recommended for patients with acute myocardial infarction without gross circulatory impairment.

Adult↗
PubMed1976

The effect of anaesthesia of the airway in dog and man: a study of respiratory reflexes, sensations and lung mechanics.

1. The effect of breathing an anaesthetic aerosol of 5% bupivacaine hydrochloride has been assessed in dog and man. 2. In the dog, the cough reflex was abolished and the Hering-Breuer inflation reflex severely impaired or abolished; breathing became slower and deeper; no pathological changes were found in the lungs of these dogs. 3. In man, no untoward effects resulted from a 10 min period of aerosol inhalation; there were no systematic effects on airway resistance or lung volumes and the cough reflex in response to either tactile or chemical (citric acid aerosol) stimulation was invariably abolished. The Hering-Breuer inflation reflex was impaired, but this was not associated with any change in resting ventilation. The Ve/CO2 response was enhanced after aerosol anaesthesia; subjects felt an exaggerated dyspnoea. The aerosol anaesthesia abolished the afferent pathway of a reflexly elicited bronchoconstriction in one subject. There was no effect on the ability to hold the breath, or on the quality of the associated sensation. 4. Control aerosols of sodium chloride solution or phosphate buffer produced no effects. Control experiments with intravenous infusions of bupivacaine proved that none of the effects could have been produced by systemic effects of the absorbed anaesthetic. 5. Plasma concentrations of bupivacaine in man did not exceed a recognized toxic level. The experiments demonstrate a safe reversible anaesthesia of the airways in man lasting for a period of 10-20 min.

Aerosols↗
PubMed1976

The effect of concentration on vasoactivity of bupivacaine and lignocaine.

In a double-blind trial bupivacaine 0.125, 0.25 and 0.5% and lignocaine 0.5, 1 and 2% were given intradermally to 31 volunteers. Vasoconstriction was observed more frequently at low concentrations of each drug, and vasodilatation at high concentrations. These observations were highly significant (P less than 0.001). Duration of action was unaffected by concentration, except in the case of bupivacaine 0.5%, the effect of which was longer lasting than that of other solutions.

Adult↗
PubMed1976

Intradermal study of a new local anaesthetic agent aptocaine.

In a double-blind trial in 28 human volunteers, a new local anaesthetic agent, aptocaine, was compared intradermally at 1, 2 and 3% concentrations with lignocaine 2% and bupivacaine 0.5%. In a second trial in 27 subjects, 1% aptocaine was compared with mepivacaine and prilocaine, both 1, 2 and 3%. In terms of activity as determined by area of anaesthesia, and of duration of action, aptocaine was similar to mepivacaine and more active and long-lasting than lignocaine and prilocaine. By this route aptocaine also appeared longer-lasting than bupivacaine. Duration of action was unaffected by concentration. Aptocaine had marked vasoconstrictor activity, which was maximal at 1%. These local anaesthetic properties suggest that aptocaine merits clinical trials, especially in dentistry.

Adult↗
PubMed1975

Self-poisoning and self-injury in the Oxford area. Epidemiological aspects 1969-73.

A prospective study of self-poisoning and self-injury in the Oxford area for 1972-73 and a retrospective study for 1969 has shown the following: (a) The number of admissions to a general hospital following self-poisoning and self-injury has increased by approximately 45% in 3 1/2 years. The increase is more marked in women than in men. (b) When compared with a previous study the incidence in Oxford city has quadrupled in ten years. (c) A total of 74% of men and 67% of women, aged 16 years and over, harming themselves in this way are under the age of 35 years. The repetitiveness is increasing and the proportion of those repeating the attempt was 10% within three months, and 15% within six months. (d) The rates are exceptionally high for teenage wives and single, widowed, and divorced women aged between 24-35 years. Single men show exceptionally high rates in the 35-45 year age group. (e) With the exception of married women aged between 25 and 34 years and women over 60, the rates were higher in urban than in rural areas. (f) In men the rates were higher among personal service workers, semi-skilled manual and unskilled manual workers. In women the rates were highest among non-manual, ancillary to professional (especially nurses), and semi-skilled manual workers. Male students had rates much lower than those of their age group, while female students had rates about the same as their age group. The lowest rates were among professional and 'own account' workers.

Adolescent↗