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Biomedical subjects

D Cook

Publications and source records attributed to D Cook.

At least 235 records · Page 13Linked to original sources
PubMed1982

Quantitative evaluation of cardiac parasympathetic activity in normal and diabetic man.

Heart rate and RR variation (the standard deviation of the mean RR interval for a 5-min period) were evaluated as measurements of cardiac parasympathetic nervous system activity in fasting supine diabetic (N = 22) and comparable age normal (N = 22) subjects. The rate of breathing did not effect heart rate, but was inversely related to the RR variation (r = 0.89, P less than 0.01). Heart rate was increased (P less than 0.0001) and RR variation decreased (P less than 0.05) during beta-adrenergic stimulation with isoproterenol and during parasympathetic blockade with atropine (both P less than 0.0001). Hence, the cardiac effects of beta-adrenergic stimulation may mimic the effects of diminished parasympathetic function. To evaluate parasympathetic control of RR variation, independently of possible effects of increased sympathetic activities, studies were performed during beta-adrenergic blockade with propranolol. RR variation during propranolol was less both in 14 diabetic subjects without clinical symptoms of autonomic neuropathy (P less than 0.005) and in 8 diabetics with clinical symptoms of autonomic neuropathy (P less than 0.001) when compared with 22 age-comparable normal subjects. The measurement of RR variation was very reproducible with a day-to-day coefficient of variation of 9.7 +/- 2.8% (x +/- SEM) in diabetic subjects with stable hyperglycemia. It is concluded that supine RR variation during a deep respiratory rate and during beta-adrenergic blockade is a sensitive, quantitative, and reproducible method to evaluate parasympathetic nervous activity in normal and diabetic subjects. Furthermore, cardiac parasympathetic activity may be diminished in diabetic subjects before clinical symptoms of autonomic neuropathy are evident.

Adult↗
PubMed1980

A scleral buckle pressure gauge for continuous monitoring of intraocular pressure.

An implantable variable resistance pressure gauge has been constructed from a conductive elastomere in the form of a scleral buckle which is suitable for recording intraocular pressure in vivo continuously over an indefinite period of time. The similarity of the pressure transducer to the standard scleral buckles used to reduce retinal detachments suggests that it will be tolerated over a period of years without significant effect on intraocular pressure. The electrical output from these pressure gauges appears to be both well defined and of sufficient magnitude to operate a valve to control intraocular pressure.

Animals↗
PubMed1979

Treatment of Cushing's disease with adrenal blocking drugs and megavoltage therapy to the pituitary.

Eighteen patients with Cushing's disease were seen over a 40-month period and considered for treatment by pituitary irradiation and adrenal blocking drugs. Fourteen patients entered the study and each received megavoltage therapy to give a mean dose of 4600 rad to the pituitary over 31 days. Each patient was treated for one (two patients) or two (12 patients) years with one or both of the adrenocortical enzyme inhibitors, metyrapone or aminoglutethmide to suppress cortisol secretion. Doses were adjusted to maintain urinary free cortisol secretion below 300 nmol/24 h. One patient failed to complete the trial. Normal urinary free cortisol excretion and plasma cortisol concentration were maintained after treatment in eight of the remaining 13 patients after therapy. Only one patient required cortisol replacement and normal menstrual function was restored in five of the six women. The remaining five patients relapsed and four were subsequently treated by total adrenalectomy. It was noted that the patients who responded to treatment were substantially younger than the therapeutic failures. It is suggested that this treatment is most useful in the management of younger patients.

Adrenocorticotropic Hormone↗
PubMed1977

The effect of 1alpha-hydroxyvitamin D3 in pre-dialysis renal bone disease.

Assessment of 18 azotaemic patients treated with long-term 1alpha-hydroxyvitamin D3 (1alpha-OHD3) confirms the generally favourable effect of this analogue of 1,25-dihydroxyvitamin D3 in azotaemic osteodystrophy. Growing children with radiological rickets respond very well as do adults showing mild hyperparathyroidism with or without osteomalacia. However, patients with severe 'pure' hyperparathyroidism and features of autonomy do not respond well and in such patients 1alpha-OHD3 alone should be avoided. Phosphate restriction and occasionally a sub-total parathyroidectomy may be indicated in these patients.

Adolescent↗
PubMed1975

Relations between sales authorisation and pharmacopoeia.

At a time when the production and distribution of drugs and drug products is no longer confined within the national boundaries of particular countries, many thoughtful people are concerning themselves with the idea of standardisation of quality control procedures and specifications. For medicines currently marketed in different countries, a multitude of standards and specifications for both the raw materials and finished products exists. Plans for the regionalisation of drug standards have been put into operation but realistic estimates of progress agree that it will be measured and dignified. In one area there is the possibility for earlier action in reaching agreement on adequate specifications. The process of registration of a new drug substance for the first time presents an opportunity to make known to drug regulation authorities, academic and industrial pharmaceutical specialists, and other interested parties, the qualities and characteristics of the newly proposed agent and its dosage forms. A wide range of information will be needed on the chemical, physical, biological and physicochemical properties of the dosage forms as well as the raw materials of the active and inactive ingredients. Many of these requirements have already been described (3). There may be apprehension that the disclosure of some of this information could imperil the confidentiality of certain manufacturing processes or trade secrets, and adequate steps would be demanded to prevent this happening. The promulgation of a standard, at or shortly after the time of registration, should have been preceded by experimental tests, in the laboratories of the Authority, to verify the robustness of the analytical methodology. In some cases more extensive confirmation by collaborative study may be warranted. The elaboration of these concepts will be presented and examples brought forward of problems that have occurred in the past, and means to prevent them in the future.

Legislation, Pharmacy↗