PubMed Health⌕ Search

Biomedical subjects

B J Gray

Publications and source records attributed to B J Gray.

16 recordsLinked to original sources
PubMed1988

Cough threshold to citric acid in diabetic patients with and without autonomic neuropathy.

The cough reflex has been investigated in insulin dependent diabetic patients with and without autonomic neuropathy. The cough response to inhaled citric acid was determined in eight patients with diabetes who had severe autonomic neuropathy and compared with that in 10 who had no evidence of neuropathy. The patients with autonomic neuropathy had a higher median threshold for the cough response to citric acid (median 50%, range 20- greater than 100%) than non-neuropathic control patients (median 10%, range 2-20%). These results suggest that vagal innervation of the bronchial tree is damaged by diabetic autonomic neuropathy.

Adult↗
PubMed1987

Transcutaneous oxygen tension during exercise in patients with pulmonary emphysema.

Transcutaneous PO2 (tcPO2) and arterial PO2 (PaO2) were compared during exercise in six patients with pulmonary emphysema. For calibration purposes, the tcPO2 electrode was first attached to the skin and after stabilisation its reading was adjusted to correspond to the PO2 of an initial arterial blood sample. It was shown that tcPO2 measurement could follow accurately the rapid changes in PaO2 occurring during exercise. Sixty-eight paired comparisons of PaO2 and tcPO2 were available and the regression equation was given by: tcPO2 (mmHg) = 0.98 PaO2 + 0.7 (correlation coefficient, 0.985; 95% confidence limits, 5.7 mmHg).

Aged↗
PubMed1987

In vivo calibration of a transcutaneous oxygen electrode in adult patients.

Transcutaneous oxygen tension (tcPO2) has been compared with arterial oxygen tension (PaO2 in 14 haemodynamically stable patients in an intensive care unit. Two calibration methods have been compared: (1) "In vitro" calibration, a two point calibration procedure carried out before attachment to the skin. (2) "In vivo" calibration, calibration using a single arterial sample, to recalibrate the upper point after attachment of the electrode to the skin and stabilisation of the electrical output. After "in vitro" calibration the regression equation was given by tcPO2 (mmHg) = 0.58 PaO2 + 13.4 (95% confidence limits +/- 19.6). After "in vivo" calibration, the regression equation for 55 comparisons over the range 50 to 120 mmHg was given by: tcPO2 (mmHg) = 0.98 PaO2 + 1.6 (95% confidence limits +/- 6.6). The "in vivo" calibration method therefore allows a close estimate of PaO2 to be made from tcPO2 values in adult patients providing strict operating criteria observed.

Adult↗
PubMed1985

Assessing effective obturation.

The use of lung function tests and sequential radiography appear to be suitable complementary methods of contrasting the effectiveness of obturator prostheses provided in the management of maxillectomy patients. The creation of an oral seal, demonstrable by normal subjects during swallowing and in the production of certain speech sounds, appears to be unobtainable in the management of maxillectomy. Effective obturation produces sufficient separation of the oral cavity from the nasal cavity to permit efficient swallowing and intelligible speech. These two methods also offer simple means to evaluate subjective experiences of the patient.

Cineradiography↗
PubMed1985

Effect of rifampicin administration on theophylline pharmacokinetics in humans.

Theophylline pharmacokinetics were studied before and after rifampicin administration (600 mg daily for 1 wk). Rifampicin reduced the area under the concentration-time curve by 18% after the oral administration of sustained release aminophylline (450 mg) to 7 normal subjects (p less than 0.05) and increased the metabolic clearance and volume of distribution by 45% (p less than 0.05) and 17% (p less than 0.05), respectively, after the intravenous administration of aminophylline (5 mg/kg over 30 min) to 8 normal subjects. These findings are consistent with an inducing and choleretic effect of rifampicin on theophylline disposition. In patients receiving theophylline, blood levels should be monitored closely and dosage adjusted if rifampicin therapy is introduced or withdrawn.

Adult↗
PubMed1984

Diminished bronchial reactivity to cold air in diabetic patients with autonomic neuropathy.

To investigate the role of neural pathways in the nonasthmatic response to eucapnic hyperventilation with below freezing air five diabetic patients with severe symptomatic autonomic neuropathy were studied. Their responses were compared with those shown by five diabetic patients without autonomic neuropathy and five non-diabetic controls. After bronchial provocation testing with cold air the diabetic patients with autonomic neuropathy did not show a significant fall in specific airways conductance (mean (SE) maximum percentage fall 2.0 (3)%), whereas conductance fell in the diabetic patients without neuropathy by 30.8 (2.0)% (p less than 0.001) and in the non-diabetic controls by 22.7 (4.6)% (p less than 0.02). In subjects who do not have asthma the bronchial response to cold air is mediated largely via neural mechanisms.

Adult↗
PubMed1984

Stepfamilies: a concern health education should address.

In this country there are more than 1 million children who find themselves in a stepfamily situation. Coping with the changes involved can be a difficult process. Health educators need to recognize the fact that many children are in this situation. Through the subunits included in the family life unit, young people can be taught how to deal with the issues involved. In so doing, health education will be addressing another major family life problem in our society.

Child↗
PubMed1984

Changes in transcutaneous oxygen tension during exercise in pulmonary emphysema.

Continuous measurements of transcutaneous oxygen tension (tcPO2) were made in 23 patients with radiological evidence of emphysema, at rest and during a maximal progressive exercise test. tcPO2 during the final phase of exercise was compared with tcPO2 at rest; the mean change (exercising minus resting value) in tcPO2 (delta tcPO2) was -0.8 mm Hg (SD 10.5, range -18 to +25) (-0.1 kPa (SD 1.4, range -2.4 to +3.3]. delta tcPO2 was correlated with: resting arterial oxygen tension (PaO2) (r = 0.606, p less than 0.005); resting arterial carbon dioxide tension (PaCO2) (r = -0.691, p less than 0.001); FEV1 % predicted (r = 0.688, p less than 0.001); vital capacity % predicted (r = 0.543, p less than 0.01); and transfer factor (TLCO) % predicted (r = 0.604, p less than 0.005). There was no significant difference between the delta tcPO2 of 10 patients who regularly produced sputum and of 13 patients with no sputum. delta tcPO2 appears to be more closely related to the severity of emphysema than to the presence or absence of chronic bronchitis. Pretreatment with fenoterol aerosol resulted in an increased work load in three out of 10 patients. Overall there was no change in delta tcPO2. In all except one patient there was a rise in tcPO2 after the end of exercise. In the 11 patients whose tcPO2 fell during exercise, tcPO2 returned to the resting value within two minutes of the cessation of exercise; this was followed by a further rise beyond the resting value, and a single postexercise arterial sample is therefore a poor indicator of the response of PaO2 to exercise. Measurement of TcPO2 is of value in following rapid changes in PaO2 during and after exercise and avoids the necessity for an indwelling arterial cannula.

Carbon Dioxide↗
PubMed1983

The bronchial response to cold air challenge: evidence for different mechanisms in normal and asthmatic subjects.

We have investigated possible mechanisms of response to airway cooling by studying the effects of sodium cromoglycate and ipratropium bromide on the changes in airways resistance that followed eucapnic hyperventilation with subfreezing air in a group of 12 patients with mild asthma and 10 normal subjects. We have also studied the period of refractoriness to repeated challenge. Maximum bronchoconstriction was not reduced after the second challenge, but in the asthmatics the one-second forced expiratory volume recovered more rapidly after the second challenge. The response in normal subjects was completely abolished by ipratropium bromide (p less than 0.0005) whereas sodium cromoglycate was without effect. In the asthmatics both ipratropium and cromoglycate were effective in attenuating the response (p less than 0.005). These results suggest that in normal subjects the response to airway cooling is produced predominantly via neural mechanisms, whereas in asthmatics there is an additional mechanism which can be abolished by sodium cromoglycate.

Adolescent↗
PubMed1983

Adverse effect of rifampicin administration on steroid-dependent asthma.

Induction of steroid metabolism has been reported after rifampicin administration but it is not known how much corticosteroid requirements increase and whether disease control can be satisfactorily maintained with increases in corticosteroid dosage. Because rifampicin may be needed in the treatment of tuberculosis in patients with steroid-dependent asthma, the dose of prednisolone needed to control this condition after rifampicin administration (600 mg daily for 6 wk) was determined in 6 patients in a randomized, double-blind, placebo-controlled trial. The plasma elimination half-life and bioavailability of prednisolone decreased significantly after rifampicin administration, but despite an increase of 93% in the dose of prednisolone (p less than 0.02), asthma control remained inferior compared to placebo. Asthma relapse in a seventh patient necessitated withdrawal from the trial after 2 wk of rifampicin administration despite a five-fold increase in prednisolone dosage. It is concluded that despite substantial increases in the dose of prednisolone the coadministration of rifampicin and prednisolone to steroid-dependent patients may seriously complicate their clinical management.

Adult↗
PubMed1982

A comparative double-blind study of the bronchodilator effects and side effects of inhaled fenoterol and terbutaline administered in equipotent doses.

Increasing doses of fenoterol and terbutaline were administered by inhaler to 12 stable asthmatics in a double-blind crossover trial. 100 microgram doses of fenoterol were shown to be equal in potency to 250 microgram doses of terbutaline, as measured by increases in forced expiratory volume in the first second (FEV1) and specific airways conductance (sGaw). FEV1 and sGaw remained significantly greater than pretreatment levels up to five hours after both drugs and terbutaline showed a significantly greater effect on FEV1 than fenoterol after four hours suggesting a small but significantly longer duration of activity. Fenoterol used at the dosage of 100 micrograms per puff (half the standard commercially available dose of 200 micrograms per puff) caused significantly more cardiac effects than terbutaline, as measured by the magnitude and duration of increases in heart rate, and the incidence of reported palpitations.

Adolescent↗
PubMed1979

Bronchial artery embolization in the control of massive haemoptysis.

Bronchial artery embolization is a useful palliative treatment for life-threatening haemoptyses where surgery is contra-indicated. Patients presenting with haemoptyses complicating cystic fibrosis and aspergilloma have been embolized. Control of haemoptysis was achieved in the former, but late recurrence of haemoptysis in the latter led to asphyxiation.

Adolescent↗