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Biomedical subjects

T J Charles

Publications and source records attributed to T J Charles.

15 recordsLinked to original sources
PubMed1998

The 'balanced force' concept for instrumentation of curved canals revisited.

The principal characteristics of K-type files are described and the succession of operations as prescribed by the 'balanced force' method of preparation of root canals, particularly curved root canals, examined. On the basis of a simple mathematical model, the motions of a file in a straight canal and in a curved canal are successively considered, and the merits of the recommended method highlighted and confirmed.

Dental Pulp Cavity↗
PubMed1985

Thiamine deficiency at a district general hospital: report of five cases.

Five biochemically severe cases of thiamine deficiency presented to one medical firm within an 11-month period at a district general hospital in Wales. In two patients the presenting feature was oliguric functional renal failure, with frank cardiovascular beri-beri. In one of these renal failure developed over a period of seven days, the cause being recognised after 20 days of continuous high-calorie intravenous feeding including daily vitamin supplements. Three further cases illustrate how early recognition and adequate treatment of the renal and cardiovascular components of thiamine deficiency may be life-saving.

Acute Kidney Injury↗
PubMed1981

Arterial plasma histamine after exercise in normal individuals an in patients with exercise-induced asthma.

1. Arterial plasma histamine concentrations, forced expiratory volume in 1.0 s (FEV1.0) and peak expiratory flow rate were determined in nine patients with exercise-induced asthma and in five control subjects before and after 8 min of cycle-ergometer exercise. 2. In the controls neither FEV1.0 nor peak expiratory flow rate fell by more than 5% in any individual during the 30 min postexercise period. The asthmatic patients all experienced a fall in FEV1.0 or peak expiratory flow rate, or both, of 15% or more in the period 5-20 min after completion of the exercise. 3. There was no difference between the control subjects and the asthmatic patients in the plasma histamine response to exercise. In both groups there was an insignificant rise of about 40% during exercise, although the initial levels were higher in the asthmatic patients. 4. The mean plasma histamine peak of the asthmatic patients preceded the mean maximal fall of FEV1.0 and peak expiratory flow rate by approximately 15 min. However, no positive correlation was found between rise in, or peak, plasma histamine levels and decrease in lung function. 5. Three non-atopic asthmatic patients had a significantly higher mean plasma histamine concentration during exercise than had the atopic subjects. 6. A strong positive correlation in asthmatic patients, and asthmatic and control subjects together was found between age and mean postexercise plasma histamine concentrations. 7. The results do not support a direct role for histamine in the production of exercise-induced asthma.

Adult↗
PubMed1981

Plasma cyclic nucleotide levels in exercise-induced asthma.

It is known that sympatho-adrenal control of airways is increased in asthma since beta blockade can cause severe bronchoconstriction in asthmatic individuals. It has not been established whether an altered catecholamine response to exercise plays any part in the production of the common symptom of exercise-induced asthma (EIA). We have investigated this indirectly by measuring arterial plasma cyclic nucleotide levels in 10 subjects with EIA and five normal subjects. Cyclic AMP, which in this context reflects beta stimulation, rose significantly by 25.4% in the normal subjects during exercise, while there was no significant change during or after exercise (less than 5%) in the asthmatic subjects. Cyclic GMP rose significantly after exercise in the asthmatic subjects. Six normal subjects repeated the protocol before and after inhalation of salbutamol aerosol, 1600 microgram daily for 18 days. This did not reduce the cAMP response to exercise, and we conclude that the diminished cAMP response of the asthmatic subjects was not caused by their medication. The results may indicate either impaired catecholamine production or endogenous beta receptor hyporesponsiveness in some asthmatic subjects and this may contribute to the development of EIA.

Adult↗
PubMed1979

Asthma in the elderly: an epidemiological survey.

A random sample of one in eight people aged 70 and over living at home in a south Wales town was surveyed to establish the prevalence of asthma. Subjects attended a screening clinic, where spirometry before and after an inhalation of salbutamol, skin prick testing, blood count, and sputum examination were carried out and a questionnaire answered. Those in whom asthma seemed at all likely were subsequently examined in detail in a chest clinic. Out of 485 subjects eligible, 418 (86.2%) were screened. Twelve (2.9%) had current asthma, of whom three had not previously been diagnosed as asthmatic and four were being treated but were unaware of the diagnosis. A further 15 (3.6%) had mild asthma or a history of the disease, giving a total prevalence of any history of asthma of 6.5%. Only one of the subjects who did not attend the screening clinic was known to have asthma, suggesting that the overall prevalence did not differ greatly from this figure. It was found that the disease might start or remit at any age. Thus in the elderly current asthma is more prevalent in men than women (5.1% compared to 1.8%) and in terms of spirometry is more severe. Two underlying disease processes may perhaps exist that fulfil criteria for asthma in the elderly, one causing sputum eosinophilia and the other a form of chronic bronchitis with reversible airways obstruction.

Aged↗
PubMed1979

Pulmonary telangiectasia.

Two patients with pulmonary telangiectasia are described. One of these is by far the oldest yet reported. The diagnosis and prognosis of this condition are discussed.

Child↗
PubMed1977

Betamethasone valerate inhalation and exercise-induced asthma in adults.

The effect of regular inhalation of betamethasone valerate (800 microgram daily) on exercise-induced asthma has been studied in 18 adult patients. The active aerosol was compared with placebo in a double-blind cross-over study, each inhaler being used for four weeks. Exercise tests after each period of treatment were performed using a cycle ergometer, care being taken to match the oxygen uptake during exercise each time a patient was tested. Twelve patients experienced less exercise-induced fall in peak expiratory flow rate after the corticosteroid inhaler, while six did not. This effect appeared to be independent of any alteration in base-line lung function, suggesting that it was due primarily to diminution of bronchial hyperreactivity. It is suggested that this change may have been due to interference with the synthesis or release of mediator substances from mast cells.

Adolescent↗
PubMedDate not supplied

Cholinergic crisis following treatment of postoperative urinary retention with distigmine bromide.

Distigmine bromide is a long-acting anticholinesterase, available for the treatment of postoperative urinary retention. Its effectiveness is unproven and administration may be hazardous. We describe a case in which oral distigmine bromide was used for postoperative retention, resulting in a potentially life-threatening 'cholinergic crisis'. We review the literature and conclude that the use of oral distigmine bromide in postoperative urinary retention is not justified.

Adult↗