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Biomedical subjects

B Tiplady

Publications and source records attributed to B Tiplady.

At least 37 records · Page 2Linked to original sources
PubMed1990

A comparison of the CNS effects of enprofylline and theophylline in healthy subjects assessed by performance testing and subjective measures.

1. The effects of intravenous infusions of enprofylline, theophylline, and placebo on subjective ratings and on psychological test performance were studied in a double-blind crossover experiment in 12 healthy subjects who abstained from caffeine throughout the experimental procedures. 2. Mean plasma concentrations of enprofylline were: mean 2.9 mg l-1 (range 1.9-3.4). Those for theophylline were: mean 12.1 mg l-1 (range 9.0-14.4). 3. Performance on the auditory vigilance task showed a significant improvement with theophylline compared with both enprofylline and placebo. The correct detection rates (out of 90) were 50.3, 43.4 and 39.1 respectively. A similar effect was seen with finger tapping rates: 404, 394 and 390 taps min-1 respectively. Other measures showed no significant effects, although choice reaction time showed a trend towards faster responses with theophylline. 4. Subjective ratings showed that subjects were significantly more alert with theophylline than with enprofylline. Subjects reported themselves as significantly more dizzy and ill with both active drugs compared with placebo. 5. These results suggest that emprofylline largely lacks the CNS stimulant effects of theophylline, but that the incidence of other unwanted effects of the drugs may be similar.

Acoustic Stimulation↗
PubMed1988

"First-dose" response to mianserin: effects of age.

The effects of single 10 mg oral doses of the antidepressant mianserin on psychomotor performance, subjective sedation and supine and standing blood pressure were compared in ten young and nine elderly healthy volunteers. Immediate and residual sedation following this subtherapeutic dose was readily detected in both groups. In contrast to previous studies with benzodiazepines, the sedation effect was not accentuated in the older subjects. Subjective awareness of sedation was significant in the young but not, however, in the elderly. "First-dose" postural hypotension, presumably due to post-synaptic alpha-blockade also occurred in young subjects only. Caution may be needed on initial dosage of mianserin in young individuals who drive or undertake skilled tasks and in the elderly who may be unaware of psychomotor impairment. The reported alpha 2 receptor selectivity of mianserin might explain the lack of postural effects in the elderly, and might constitute a potentially useful characteristic in the development of new compounds.

Adult↗
PubMed1988

The effects of age on the response to caffeine.

Twelve healthy subjects, six young and six elderly, of either sex, took part in this two-period crossover study. In each session, a dose of trial drug--either 200 mg caffeine or a matching placebo--was given orally at 0900 hours. A battery of psychomotor tests and visual analogue scales was administered before treatment and at 1, 2 and 3 h post-treatment. The objective tests showed a significant increase in tapping rate in the young, while the elderly showed improved attention, faster choice-reaction time, and greater body sway on caffeine. The visual analogue scales showed that the young subjects felt more alert, calmer, more interested, and steadier on caffeine, while no significant changes were seen in the elderly. These results show that caffeine produces changes predominantly in the direction of improved performance and feeling of well-being, and suggest that the elderly are more sensitive to the objective effects of the drug, while reporting less subjective effect than the young.

Adolescent↗
PubMed1987

Effects of ethanol on psychomotor performance.

Three separate doses of alcohol (0.2, 0.4 and 0.8 g kg-1) were given to eight volunteers and compared with the effects of a placebo. The order of administration was randomized and the study performed double-blind. A battery of psychometric tests sensitive to central nervous system depression was repeatedly performed for 3.5 h. Alcohol, even in the highest dose, had little effect on psychomotor performance.

Adult↗
PubMed1984

A study of the effects of zimelidine on the pharmacokinetics and pharmacodynamics of temazepam in healthy volunteers.

In this double-blind two-period crossover study, ten healthy volunteers received either 200 mg zimelidine each morning for 5 days, or placebo on the same schedule. On day 5 they received 20 mg temazepam 2 h after zimelidine or placebo. A battery of psychometric tests and subjective measurements was carried out on days 4 and 5. Blood samples were collected on day 5 for pharmacokinetic analysis of temazepam. All the measures of psychomotor performance showed the effects of temazepam, as did two of the subjective measures, the "alert/drowsy" and "steady/dizzy" visual analogue scales. No effect of zimelidine alone on performance or subjective state was seen. Zimelidine showed no discernible interaction with the effects of temazepam as assessed by subjective reports, by psychomotor tests, or by pharmacokinetic analysis.

Adult↗
PubMed1982

Effects of amitriptyline and zimelidine in combination with ethanol.

Six healthy male volunteers took part in this three-period crossover study. In each session, a dose of trial drug -- either placebo, zimelidine 200 mg, or amitriptyline 75 mg -- was given at 09.00 h. Ethanol (50 g) was taken orally at 1200 h. Blood samples were taken for measurement of drug and ethanol concentrations, and body sway and subjective sedation were determined. No differences in the pharmacokinetics of ethanol were seen between the three treatment sessions. Amitriptyline and ethanol showed marked sedative effects, and the results suggest that these two effects may be additive. The combination of amitriptyline and ethanol results in a particularly marked increase in body sway. No sedative nor alerting effect of zimelidine was seen, nor was any interaction between zimelidine and ethanol apparent.

Adult↗
PubMed1981

Zimelidine and amitriptyline in the treatment of depressive illness in general practice.

Depressive patients seen at hospital clinics are likely to be unrepresentative in terms of treatment response. In this study patients were always seen at their general practitioners' surgeries for assessment by specialists after selection as being in need of antidepressant treatment. The Research Diagnostic Criteria for major or minor depressive illness and a Hamilton Depression (Ham-D) score of at least 10 were required for inclusion, using the Present State Examination as a basis for interview. Patients were seen at weekly intervals, alternatively by practitioner and assessor for further Ham-D ratings, completion of the Kellner Sheffield Self-Rating test (KSSRT), event record and side effect checklist. Patients were randomly and blindly allocated to either zimelidine or amitriptyline dispensed identically at dosages of 100 mg and 75 mg at night, rising to 200 mg and 150 mg after two weeks. At four weeks there was no significant difference between the improvement found with zimelidine and amitriptyline or either the Ham-D or the KSSRT. Amitriptyline patients tended to gain and zimelidine patients to lose weight; difference significant. Other amitriptyline side effects were not found in those taking zimelidine, the latter tending to suffer diarrhoea. Preliminary analysis shows no relationship between clinical response and plasma level of either compound.

Adult↗
PubMed1981

Zimelidine: comparison of different dosage regimes in general practice.

Various studies have demonstrated that depressive symptoms are a frequent and important problem in general practice. Zimelidine has been shown to have effective antidepressant activity. A controlled double-blind trial was set up to compare the efficacy and side effects of zimelidine when given as a single daily dose (200 mg night or morning) and when given as a divided dose (100 mg b.d.). These three dosage schedules were studied. The trial was conducted among patients attending their general practitioners and suffering from a depressive disorder. Using one of the three dosage schedules, these patients were treated with zimelidine for a minimum period of 6 weeks. Symptom severity was measured by means of the Hamilton Rating Scale for Depression and the side effects assessed using an adverse event record and a symptom checklist. The findings are discussed.

Adult↗
PubMed1980

Event recording in a clinical trial of a new medicine.

In a double-blind trial of the effect of zimelidine on weight and appetite 24 obese patients were allocated at random to receive either zimelidine or placebo for eight weeks followed by the alternative treatment for eight weeks. Possible adverse effects were elicited by asking patients at weekly intervals whether they had experienced any symptoms or ailments and recording all such "events" on a special form. A conventional checklist of symptoms was also used. Among 19 patients who completed the trial the two methods of recording yielded similar patterns of events. Of symptoms not on the checklist, insomnia was more common during treatment with zimelidine. Event recording was found to be a practicable and convenient method of detecting possible adverse effects.

Adult↗
PubMed1977

Primitive haemoglobin.

The sequences of Petromyzon and Aplysia globins are compared with the postulated vertebrate and mollusc-vertebrate ancestors to see if differences exist in the rates of evolution of different types of residue positions. Between the mollusc-vertebrate ancestor and Aplysia globin there is no very striking pattern of changes except that the interior positions are relatively conserved. In the evolution of Petromyzon haemoglobin, the alpha 1 beta 2 contact area is relatively conserved. The homopolymeric binding of lamprey Hb seems to be a primitive function.

Animals↗