Biomedical subjects

E Cooke

Publications and source records attributed to E Cooke.

29 records · Page 2Linked to original sources

PubMed1983

Subcutaneous aprotinin causes local hyperaemia. A possible mechanism by which aprotinin improves control in some diabetic patients.

Local changes in blood flow at the subcutaneous injection site of the proteinase inhibitor aprotinin and its diluent were measured by photoelectric plethysmography. Aprotinin, but not its diluent, caused local hyperaemia in five normal subjects and in five stable and five brittle insulin-dependent diabetic patients, local blood flow increasing by 80%-180%. The duration of the hyperaemic response was shorter in the brittle diabetic patients than in the other two groups, but there was wide individual variation. Aprotinin is known to enhance subcutaneous insulin absorption in normal subjects and in some brittle diabetic patients. The basis for this might be through increasing blood flow near the injection site rather than by inhibition of insulin breakdown.

Adult↗

PubMed1983

Changes in blood flow close to subcutaneous insulin injection sites in stable and brittle diabetics.

Photoelectric plethysmography (PPG) was used to investigate blood flow changes close to superficial subcutaneous injection sites. As a validation procedure, the PPG response to subcutaneous injection of a known hyperemic agent, prostaglandin E1 (10(-5) M), was shown to correlate strongly with subcutaneous blood flow changes estimated by the established technique of 133Xe washout. Changes in blood flow over the subcutaneous injection sites of insulin (Actrapid) and insulin diluent were measured by photoelectric plethysmography in six nondiabetics and in six stable and seven brittle insulin-dependent diabetics. In all subject groups, an acute increase in local blood flow was seen within 2 min of both insulin and diluent injections, probably caused by injection trauma. At diluent injection sites, this acute hyperemia faded rapidly, blood flow returning to preinjection levels within 15-20 min, and there was no further increase in blood flow in any of the subjects. Insulin injected into the nondiabetics and stable diabetics caused a pronounced increase in local blood flow, sustained for at least 60 min after injection. In the brittle diabetics, however, there was no prolonged local hyperemia, the response being significantly less than that seen in both the nondiabetics and the stable diabetics. Insulin-related hyperemia close to injection (or infusion) sites may be important in subcutaneous insulin absorption. Its near-absence in brittle diabetics may contribute to the impaired response to subcutaneous insulin characteristic of these patients.

Adult↗

PubMed1981

Electrodermal activity in the affective disorders and schizophrenia.

Electrodermal activity was measured bilaterally at rest and during stimulation in 22 schizophrenic, 11 depressed and 12 anxiety state patients, and in 32 normal volunteers. No group showed a distinctive pattern of lateral asymmetry. The frequency of spontaneous fluctuation in electrodermal activity was greater in the anxiety state and schizophrenic groups and in those patients who reported auditory hallucination during recording. Few schizophrenic subjects failed to respond to visual stimulation but substantial minority failed to habituate. The implications of these findings are discussed.

Adolescent↗

PubMed1981

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PubMed1980

Habituation of physiological responses in anxiety.

In the first study, 20 male and 20 female volunteers were studied under threat-of-shock and no-threat conditions with respect to anxiety levels, skin conductance, EEG auditory evoked response, and alpha-blocking variables. The threat-of-shock increased anxiety levels, skin conductance level, and fluctuations. The P300 component of the AER was greater in anxious individuals and habituation of the alpha-blocking response was retarded. In the second study, 12 anxious patients were compared with 12 normal subjects under threat-of-shock and 12 normal subjects under no-threat. Anxiety was associated with increased skin conductance fluctuations, larger P300 AER components, and impaired habituation of the alpha response.

Adult↗

PubMed1979

The effect of temporal lobe surgery on electrodermal activity: implications for an organic hypothesis in the aetiology of schizophrenia.

It has recently been suggested that the bilateral asymmetry of electrodermal activity (EDA) reported in schizophrenia may be related to unilateral temporal lobe dysfunction. To test this hypothesis, 3 aspects of EDA--skin conductance level (SCL), number of spontaneous fluctuations (SF), and skin conductance response (SCR)--were measured bilaterally in 10 patients who had undergone unilateral temporal lobectomy. No differences could be detected between the operated and non-operated sides within the patient group, nor between the patient and control groups. The implications of these findings are discussed.

Adult↗

PubMed1979

Computer analysis of fetal heart rate variation during normal pregnancy.

Ninety-seven one-hour recordings of the abdominal fetal electrocardiogram (ECG) were made from 59 normal patients between 21 and 41 weeks of gestation. The heart intervals, measured between successive R-waves, were analysed by computer. The signal-to-noise ratio of the fetal ECG limited the precision of the interval measurements to approximately one millisecond. The characteristics of the baseline heart rate changed significantly as gestation advanced, the mean R-R interval, the standard deviation of the intervals and the standard deviation of the interval differences all increasing with gestation (p less than 0.001). In later gestation the baseline heart rate during periods of fetal rest differed significantly from that during periods of fetal activity; during rest the mean R-R interval was greater (p smaller than 0.001) and the standard deviations of the intervals and interval differences were smaller (p smaller than 0.001). Examination of the coefficient of variation of the heart intervals gave a result which contradicted the significance of this measurement as an index of fetal welfare as proposed by Curran and MacGregor (1970).

Analysis of Variance↗

PubMed1898