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Biomedical subjects

M A de Kock

Publications and source records attributed to M A de Kock.

13 recordsLinked to original sources
PubMed1989

The flow/volume curve as a mass screening test with emphasis on quality control.

Air flow through the airways is influenced by different mechanical characteristics of the respiratory system and can be affected by pathological changes in the lungs. Lung volume is probably the most important independent variable determining air flow through the airways. Therefore, it is logical that lung volume should form the ordinate of a curve used to demonstrate the variation of airflow through the airways during forced inspiratory and expiratory manoeuvres. The flow/volume curve is in many ways superior to other measurements of lung function for clinical and epidemiological assessments. Most of the problems that have to be overcome in obtaining satisfactory and repeatable flow/volume curves are discussed and illustrated. A computer system which optimises quality control is described. By making use of this system, operator error can be reduced to a minimum. It is recommended that hard copies of the three efforts must be available and that all flow/volume measurements be controlled by a knowledgeable person before the results are entered in the records.

Adult↗
PubMed1988

Influence of a fibrothorax on the flow/volume curve.

Rigidity of the thorax with relatively 'normal' lungs can show typical changes in the flow/volume curve that could be diagnostic. These changes caused by 'entrapment' of the lungs are described and illustrated by means of a case report of a patient with bilateral fibrothorax caused by bilateral tuberculous pleural effusions.

Adult↗
PubMed1982

Influence of vagus nerve on catecholamine production of dog lungs.

The effect of electrical stimulation of the cut cervical vagal nerves in dogs on airway resistance and circulating catecholamine concentrations was determined before and after propranolol. Airway resistance increased after 1 min of stimulation and decreased after 9 min of stimulation. The circulating catecholamine levels increased significantly in the pulmonary artery after 1 min of stimulation. After 9 min of stimulation the increase in the femoral artery was relatively more than in the pulmonary artery. This late increase most probably represents catecholamine supply from lung structures.

Airway Resistance↗
PubMed1979

A new lung function index: the area under the maximum expiratory flow-volume curve.

A new lung function index, the area under the maximum expiratory flow-volume curve (AFVx) is described. A predicted AFVx based on age, sex and height is determined, and the measured to predicted AFVx ratio is assessed by comparison with other established lung function parameters. This ratio appears to be a very sensitive indicator of the degree of lung function impariment.

Age Factors↗
PubMed1978

Role of alpha-adrenergic receptors in exercise-induced bronchoconstriction.

The role of alpha-adrenergic receptors in exercise-induced bronchoconstriction (EIB) was studied. 9 asthmatic patients with a marked degree of EIB (group I) and 6 asthmatic patients with no or a less severe EIB (group II) were investigated and compared with 8 healthy control persons. Pulse rate, airway resistance and end-expiratory thoracic gas volume were measured at rest and immediately and 15 min after exercise. Group I subjects showed a significant inhibition of EIB after alpha-adrenergic blockade with phentolamine (10 mg as aerosol) and after cholinergic blockade with an atropine-ester (60 mg as aerosol). In 7 of 9 patients who had received phentolamine, and in 3 of 6 patients who had received atropine-ester, the EIB was completely suppressed. In group II the administration of propranolol (40 mg orally) produced a significant increase in EIB. The effect of propranolol could be inhibited by the addition of alpha-adrenergic blockade with phentolamine (10 mg as aerosol). The control subjects had no measurable EIB, even after the administration of propranolol (40 mg orally). It is concluded that, in addition to the vagal system, an activated alpha-adrenergic system is involved in the phenomenon of EIB.

Adult↗
PubMed1978

The diagnostic value of lysosomal enzyme patterns in bronchial aspirates of patients with suspected bronchial carcinoma.

The measurement of the activity of acid hydrolases and of alkaline phosphatase in bronchial aspirates obtained through bronchoscopic procedures from a series of 300 patients forms the basis for a screening program to diagnose bronchial malignant neoplasms more effectively. We define such a screening test as one permitting rapid measurements indicative of pathologic abnormalities and producing a preliminary diagnosis which, if in error, yields preferably a false-positive result. Using this approach, we demonstrated that an elevation of the activity of alkaline phosphatase or cathepsin D predicts a 50 percent likelihood of cancer, but elevation of both the concentrations of alkaline phosphatase and cathepsin D has an additive prediction of 71 percent. Data obtained in this study showed that the presence of a pulmonary tumor can cause increased levels of alkaline phosphatase or cathepsin D (or both) in bronchial aspirates before the presently accepted methods yield a diagnostic result. Furthermore, those patients with an elevated activity of alkaline phosphatase or cathepsin D (or both) but with no histologically demonstrable pulmonary carcinoma can be reexamined intermittently.

Acid Phosphatase↗
PubMed1975

[Comprehensive lung function test for outpatients: a present-day review and its application].

A method for the measurement of recognised lung function parameters is described. Bedsides being useful for the detection of early pathology, the information obtained by this method is generally sufficient for an early diagnosis. A large number of patients can be examined per day and the test is also informative in high-risk pre-operative patients. Furthermore, the method is suitable for epidemiological studies and has already been used by the Medical Research Council to determine the incidence of chronic obstructive lung disease in the Bellville area.

Humans↗
PubMed1975

A preliminary study of elevated alkaline phosphatase and cathepsin in bronchial aspirates of patients with lung cancer and bronchitis.

The measurement of acid and alkaline phosphatase and cathepsin activities in bronchial aspirates obtained through bronchoscopy from a series of 75 patients suggests a procedure that may have value as a routine diagnostic examination. Using this approach, seven patients with neoplasms in the lung showed elevated levels of alkaline phosphatase and cathepsin in bronchial aspirates without elevation in acid phosphatase activity.

Acid Phosphatase↗