Biomedical subjects
N R Peden
Publications and source records attributed to N R Peden.
Nadolol and potassium iodide in combination in the surgical treatment of thyrotoxicosis.
With the two aims of rapidly reducing circulating thyroid hormone levels and controlling the symptoms of thyrotoxicosis, we have prepared 17 thyrotoxic patients for subtotal thyroidectomy, using a combination of potassium iodide administered for 10 days and the long acting beta-adrenoceptor antagonist nadolol. All 17 patients had normal serum thyroxine levels after 10 days of such treatment although 10 still showed elevation of serum tri-iodothyronine and considerable elevation in the most severely toxic patient. All patients were, however, clinically euthyroid preoperatively. Nadolol was administered once daily, hence avoiding the problems of drug administration in the immediate postoperative period, and plasma nadolol concentrations were high throughout the perioperative period. Serum thyroxine and tri-iodothyronine levels were significantly lower and reverse tri-iodothyronine levels higher 24 h postoperatively than before operation. All patients remained stable throughout the perioperative period. We conclude that this regimen has a number of advantages in the preparation of patients for thyroidectomy, in reducing the degree of thyrotoxicosis, in convenience of drug administration and in ensuring adequate circulating concentrations of beta-adrenoceptor antagonist whilst still retaining a relatively short preoperative phase of drug treatment.
Nadolol in thyrotoxicosis.
1 Twenty outpatients with thyrotoxicosis received the non-selective beta-adrenoceptor antagonist nadolol as sole treatment for 3 weeks. 2 Clinical improvement as measured by reduction in thyrotoxicosis therapeutic index occurred during the first week of treatment and was continued thereafter, and was accompanied by a significant reduction in serum T3 and elevation of serum reverse T3. 3 As measured by reduction in exercise heart rate, during chronic dosing nadolol 160 mg once daily produced blockade of beta-adrenoceptors for 12 h in all patients and 24 h in all but 2. 4 Wide interindividual variability was noted in steady state plasma nadolol concentrations, in part related to age and renal function. 5 Steady state plasma nadolol concentrations were related to reduction in heart rate.
Gastric mucosal histamine and histamine methytltransferase in patients with duodenal ulcer.
Histamine and histamine methyltransferase (HMT) have been measured in gastric mucosa from 110 patients with duodenal ulcer and 62 control subjects. Both antral and fundic mucosa had similar levels of HMT activity despite antral mucosa containing significantly less histamine. Patients with duodenal ulcer had significantly lower levels of fundic mucosal HMT activity and lower concentrations of fundic mucosal histamine than control subjects. An additional finding was that men who were cigarette smokers had significantly lower concentrations of fundic mucosal histamine (but not HMT) than non-smokers and, as there was an excess of cigarette smokers among patients with duodenal ulcer, this may be the explanation for the reduced concentrations of fundic mucosal histamine in these patients.
Mitogen stimulation of peripheral blood lymphocytes of duodenal ulcer patients during treatment with cimetidine or ranitidine.
During a double-blind randomised clinical trial of cimetidine and ranitidine in the management of duodenal ulcer, the response of patients' peripheral blood lymphocytes to optimal mitogenic stimulation in vitro has been measured. Treatment with cimetidine, but not ranitidine, was associated with a significant increase in the proportion of peripheral blood lymphocytes responding to this optimal mitogenic stimulation. We conclude that these effects of cimetidine may not be mediated at classical histamine H2-receptors.
The problem of psilocybin mushroom abuse.
1 We have reviewed the clinical features and management of 44 consecutive patients presenting to hospital over a 5 week period during an outbreak of ingestion of psilocybin containing mushrooms. 2 Patients presented to hospital usually because of dysphoric effects an average of 3.8 h after ingesting mushrooms. 3 Mydriasis was present in 40 patients but fewer than half showed other sympathomimetic features--tachycardia, hypertension or hyperreflexia. 4 Twenty-three patients experienced nausea and vomiting. 5 Distortions of perception chiefly visual were frequent as were paraesthesiae and feelings of depersonalization. 6 The effects of the mushrooms were short-lived and had worn off within 12 h in all but one patient. 7 Inducing emesis did not appear to hasten recovery from the effects of the mushrooms.
The effects of impromidine and pentagastrin on gastric output of histamine, acid and pepsin in man.
Histamine and hydrogen ion concentrations and peptic activity have been measured in gastric juice in 8 normal subjects during infusion of pentagastrin, pentagastrin plus cimetidine, and impromidine. The stimulation of gastric secretion under all 3 conditions produced an initial increase in histamine concentration and output in gastric juice, which was not sustained. The total stimulated histamine output in one hour was similar with pentagastrin and pentagastrin plus cimetidine, but was significantly higher with impromidine (p less than 0.05), a histamine methyltransferase in normal human gastric mucosa. These results do not support the concept that histamine is the final local common chemostimulator of the parietal cell in man.
Effect of cimetidine on gonadal function in man.
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Women and duodenal ulcer.
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Symptom relief and the placebo effect in the trial of an anti-peptic drug.
In order to determine some of the factors involved in the response of duodenal ulcers to placebo treatment, the following factors were studied prospectively during a double-blind, placebo-controlled trial: demographic data; duration of illness and effect of treatment; expectation of success or failure of the new drug; presence of psychiatric problems; and suggestibility. Healing (measured by endoscopy) occurred in 37 patients, 17 of whom were receiving placebo; relief of symptoms occurred in 35 patients, 16 of whom were receiving placebo. There was no significant difference between drug and placebo. Healing was significantly associated with relief of symptoms but with no other variable. Relief of symptoms was more common in male patients and in those from higher social classes, as well as in patients who expected a complete cure and those without evidence of psychiatric problems. the natural history of the disease may be different in these patients. Unexpectedly, suggestibility was not associated with healing or relief of symptoms in the patients receiving placebo.
Clinical toxicology of "magic mushroom" ingestion.
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Effects of two histamine H2-receptor blocking drugs on basal levels of gonadotrophins, prolactin, testosterone and oestradiol-17 beta during treatment of duodenal ulcer in male patients.
In a study of 51 male patients with duodenal ulcer, treatment with cimetidine was accompanied by an increase in basal levels of serum testosterone. Treatment with ranitidine, a new histamine H2-receptor antagonist, produced no such effect. It is concluded that cimetidine had antiandrogenic activity in man which is separate from the histamine H2-receptor blocking activity.
Ranitidine in the treatment of duodenal ulceration.
In a randomized, double-blind, endoscopically controlled clinical trial, 40 patients with duodenal ulcer were treated with either ranitidine (320 mg/day) or cimetidine (800 mg/day) for 28 days. The rate of healing of the ulcers (ranitidine, 78%, cimetidine, 45%) did not differ significantly in the two treatment groups. In a subsequent 'open' study, ranitidine (150 mg twice daily) healed the ulcers of 79% of 19 patients treated for 28 days. Treatment with ranitidine was not associated with significant adverse reactions and had no lasting effect on gastric secretory capacity. Whereas basal levels of serum testosterone rose significantly during treatment with cimetidine, no such increase was observed during treatment with ranitidine. We conclude that ranitidine can effectively and safely heal duodenal ulcers.
Clinical and endocrine aspects of treatment with ranitidine.
Ranitidine has been shown to heal the majority of duodenal ulcers during treatment with 300 or 320 mg daily for 4 to 8 weeks. Twice-daily dosage improved compliance. Subsequent maintenance treatment with ranitidinie, 150 mg at night prevented relapse in the majority of patients during 6-months' follow-up. Ranitidine did not appear to have any anti-androgenic effects.
Cimetidine and the immune response.
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Pharmacologically effective plasma concentrations of ranitidine.
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Inhibition of pentagastrin-stimulated and nocturnal gastric secretion by ranitidine. A new H2-receptor antagonist.
Ranitidine hydrochloride (an H2-receptor-blocking drug which does not contain the imidazole nucleus of histamine) powerfully inhibited nocturnal and pentagastrin-stimulated gastric secretion in fifteen patients with duodenal ulceration. The drug is satisfactorily absorbed and therefore warrants clinical trial.
Male sexual dysfunction during treatment with cimetidine.
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