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Biomedical subjects

D W Johnston

Publications and source records attributed to D W Johnston.

At least 19 recordsLinked to original sources
PubMed1991

Stress management in the treatment of mild primary hypertension.

The use of simple relaxation-based stress management procedures in the treatment of mild primary hypertension has been the subject of extensive study. Stress management appears to lead to reliably greater reductions in pressure than a variety of control procedures. The mechanisms underlying these effects are obscure, and research has not identified which patients will benefit most from treatment. Preliminary data suggest that stress management may reduce the risk of coronary heart disease, but much research must be done if this is to be confirmed. It is suggested that such research should take into account the possibility that stress management may have beneficial effects on more than just hypertension-related aspects of the cardiovascular disease process.

Blood Pressure↗
PubMed1990

The relationship between heart rate and mood in real life.

Very little is known about the relationship between stress and cardiovascular responses in everyday settings. The three subjective states of Stress, Arousal and Time Pressure were measured every 30 min during a normal day in 32 healthy male volunteers and related to heart rate, which was measured continuously using standard ambulatory techniques. An index of the subjects physical activity was derived from the muscle activity of the thigh. Heart rate related to emotional state in very few subjects when time-series statistical methods, which take into account the autocorrelated nature of the data, were used. The relationship was further reduced when allowance was made for concurrent physical activity. The minority of subjects who exhibited a significant association between heart rate and mood variations were significantly more anxious, reported more anger, and had higher systolic blood pressures at rest than subjects who did not show a relationship between mood and heart rate.

Adult↗
PubMed1990

The relationship between cardiovascular responses in the laboratory and in the field.

The psychophysiological responses to laboratory stressors are often examined because it is believed that such responses relate to responsiveness in real life situations. This belief has seldom been tested. The changes in heart rate, pulse transit time, and respiration rate produced by a variety of laboratory tasks (active and passive coping and physical exercise) were related to ambulatory measures of heart rate in 32 young men. The field measures were the difference in heart rate between the waking day and when asleep, and estimates of the variability of heart rate during the day, derived from time series analyses. Average changes in heart rate and pulse transit time during specific tasks did not relate consistently to heart rate in the field. However, an active coping index, derived from the ratio of the peak heart rate during an active coping task to the peak during physical exercise related to all the field measures of heart rate responsiveness. This index, which may relate to measures of additional heart rate and heightened sympathetic response to stress, also correlated positively with Trait Anxiety and elevated basal sympathetic arousal, as measured by skin conductance level. Measures of the cardiovascular response to a passive coping task, the cold pressor, and exercise did not relate to heart rate responses in the field. The findings suggest that heightened cardiac responsiveness in real life is exhibited by subjects who show elevated peak responses to active coping stressors specifically.

Adaptation, Psychological↗
PubMed1990

A simple activity measure for use with ambulatory subjects.

A simple activity measure based on the EMG recorded from the thigh was developed to monitor the physical activity of ambulatory subjects. The performance of this activity measure was assessed during four major physical activities: running, walking, standing, and sitting. Heart rate was also monitored. The results were analysed within individuals using time series analysis. The heart rate and activity series (of consecutive 30-s means) required similar models within individuals, and both measures differentiated among running, walking, and non-movement. The activity measure did not discriminate between postures. This measure covaried closely with heart rate and emerged as a necessary and relatively more significant predictor of heart rate variance than knowledge of the type of physical activity the subjects were undertaking. Posture, however, did add a significant and independent contribution to heart rate variance. This activity measure appears to be a simple, reliable, and valuable method of measurement of physical activity variations in ambulatory subjects.

Adult↗
PubMed1989

An evaluation of the Takeda UA751 automatic sphygmomanometer.

The Takeda UA751, a simple automatic blood pressure measuring device, was compared with standard osciltatory measurement. There was little or no systematic difference in pressure determined by the automatic or manual method and the correlation between the two devices for both systolic and distolic pressure was satisfactory. This suggests that the Takeda UA751 is an appropriate device for patient self monitoring of blood pressure or as a measure of pressure in group outcome trials. The results essential replicate an evaluation by Steptoe and Molineux (Behav. Res. Ther. 24 223-226, 1986) of an earlier version of the Takeda (the Copal UA251) that used a different method for determining blood pressure.

Adolescent↗
PubMed1989

The effects of imminent minor surgery on the cognitive processing of health and interpersonal threat words.

Women in hospital for a laparoscopy and control subjects were examined on a version of the Stroop test in which the distracting effect of word content on speed of colour naming was examined. Both laparoscopy patients and controls were slowed by words related to interpersonal threat but only the laparoscopy patients were slowed by words that related to health threats. This suggests that a specific temporary threat can alter attentional biases.

Abdominal Pain↗
PubMed1989

Prevention of cardiovascular disease by psychological methods.

It is generally recognised that much cardiovascular disease is the result of voluntary behaviour such as smoking cigarettes, and the pursuit of stress-prone lifestyles. Since these risks are primarily behavioural, it is appropriate to attempt to alter them, and hence reduce the risk of cardiovascular disease, using psychological methods, and such methods can reduce both biological and psychological stress-related factors. Studies of healthy populations, of those at increased risk, and of patients with clear cardiovascular disease have all shown that risk-related behaviour can be altered and, in some cases, the incidence of cardiovascular disease reduced. Future research will have to extend these findings, which were often on atypical populations, and confirm reduction of cardiovascular disease.

Behavior Therapy↗
PubMed1987

Type A behaviour and ischaemic heart disease in middle aged British men.

The Bortner questionnaire, which measures aspects of type A (coronary prone) behaviour was completed by 5936 men aged 40-59 selected at random from one general practice in each of 19 British towns. The presence of ischaemic heart disease was determined at initial examination and the men were followed up for an average of 6.2 years for morbidity and mortality from myocardial infarction and for sudden cardiac death. Non-manual workers had significantly higher scores (more type A) than manual workers and the score decreased (less type A) with increasing age. After adjustment for social class and age men with higher scores had higher prevalences of ischaemic heart disease less marked for electrocardiographic evidence and more marked for response to a chest pain questionnaire (angina or possible myocardial infarction). A man's recall of a doctor's diagnosis of ischaemic heart disease, however, did not relate to his Bortner score. There was no significant relation between the Bortner score and the attack rate or incidence of major ischaemic heart disease events. In this study type A behaviour, as measured by the Bortner questionnaire, did not predict major ischaemic heart disease events in British middle aged men.

Adult↗
PubMed1987

Biologic response to uncemented Madreporic canine hip arthroplasty.

The Madreporic hip arthroplasty has provided encouraging clinical results. The surface of the prosthesis is unlike other uncemented prostheses since the rough surface is formed by multiple 1-mm diameter beads that are cast as an integral part of the prosthesis and increase its surface area four times. Seven Madreporic hip arthroplasties were implanted in adult male mongrel dogs. Specimens were harvested 5, 6, 9, 12, 20 and 52 weeks after insertion. One specimen became septic and loosened. The prosthesis was stabilized initially by friction fit between the prosthesis and the endosteal cortex of the proximal femur. Dense, uniformly organized, fibrous tissue surrounded the prosthesis at 5 weeks. The fibrous tissue appeared similar to Sharpey's fibres. Circumferential bone contact increased from 26% at 5 weeks to 60% at 52 weeks. Fluorescent labelling revealed active new bone formation within the interstices of the prosthesis without evidence of an intervening soft-tissue membrane. Firm mechanical anchorage of the Madreporic femoral prosthesis was demonstrated in this study.

Animals↗
PubMed1986

Relaxation and stress management in the treatment of essential hypertension.

Thirty-two male and female hypertensives, 34 to 65 yr of age, systolic blood pressure (SBP) less than 200 mmHg and diastolic blood pressure (DBP) between 90 and 109 mmHg, were randomly allocated to receive either relaxation and stress management (experimental condition) or mild physical exercise (control condition). Half the participants were taking antihypertensive drugs, which were constant for six months prior to the study and controlled during the study. Outcome measures included various measures of blood pressure in the clinic and at home, cardiovascular responsiveness, moods and 24-hr urinary adrenaline and noradrenaline. The study schedule consisted of 3-months baseline, 10 weeks treatment and 3-months follow-up. Relaxation was superior to the control procedure in reducing blood pressure as assessed by nurses blind to the participants' treatment at post-treatment for DBP and at follow-up for DBP and SBP.

Adult↗
PubMed1986

Can and should type A behaviour be changed?

Both Type A behaviour and the component of hostility can be reduced by a number of different psychological interventions and such reductions are associated with reduced cardiac morbidity in patients with coronary heart disease. Reductions in Type A behaviour are not associated with significant changes in other risk factors nor with unwanted side effects such as reduced professional effectiveness.

Adrenergic beta-Antagonists↗
PubMed1986

Biomechanical performance of locked intramedullary nail systems in comminuted femoral shaft fractures.

The biomechanical properties of commercially available locked nail systems designed for use in comminuted femoral shaft fractures were compared and evaluated. Ender nails as well as three forms of interlocking nails, Brooker-Wills (B-W), Klenm-Schellman (K-S), and Grosse-Kempf (G-K), were implanted in cadaver femora. The femora were tested in torsion, bending, and axial loading to failure. Two fracture models were tested--a 3 cm subtrochanteric defect and an 8 cm midshaft defect. Results of the testing revealed the three interlocking nails to be comparable to each other and superior to Ender nails in bending and torsion. However, the distally bolted locked nails (K-S, G-K) resisted significantly higher loads than either the distally bladed locked nail (B-W) or Ender nails when tested to failure by axial loading.

Adult↗
PubMed1986

Orthopedic experience with methicillin-resistant Staphylococcus aureus during a hospital epidemic.

Thirty-eight orthopedic patients with proven methicillin-resistant Staphylococcus aureus (MRSA) infections were assessed as to the effectiveness of treatment. All patients were admitted between June 1981 and September 1983 and were among the 508 patients who had positive cultures for MRSA during that period. The average age of the patients was 32.5 years. Thirty-two patients had fractures. In 70% of the patients the injury was due to a motor vehicle accident. Sixty percent of the patients had Grade III open fractures with severe soft tissue injury or associated vascular injury. All patients were given antibiotics within 30 days of a positive culture, with 97% getting a first-generation cephalosporin. There were an average of 5.5 surgical procedures per patient (range, one to 16). Nine patients (24%) required amputation and eight (21%) lost joints either by excision or fusion. Only 14 patients (37%) healed without drainage. Four patients (10%) healed the original fracture or surgery with chronic drainage. There were three nonunions, two of which continue to drain. The antibiotic cost for Vancomycin alone increased 300%, from $2,000 in 1982 to approximately $680,000 in 1983. Methicillin-resistant in 1983. Methicillin-resistant S. aureus (MRSA) has significant epidemic potential. Infection with this organism carries a high-morbidity in order to control the organism. Any reported case of MRSA should be isolated quickly and thoroughly investigated epidemiologically in an attempt to prevent an epidemic. Vancomycin is the antibiotic of choice. Emphasis should be placed on the interruption of transmission of MRSA within and among hospitals. Serious consideration must be given to the long-term effects of prophylactic antibiotics.

Adolescent↗
PubMed1985

Serum gonadotropin and ovarian steroid levels in women during administration of a norethindrone-ethinylestradiol triphasic oral contraceptive.

We studied the inhibitory effect of a triphasic oral contraceptive (OC) regimen on the pituitary and ovarian function in 29 normal, healthy women. ORTHO* 7/7/7 Tablets contain a constant low dose of ethinylestradiol (EE) and a step-wise increasing level of norethindrone (NE). The pills for the first, middle and last weeks of the 21-day regimen contained, respectively, 0.5, 0.75, and 1.00 mg NE, and all contained 0.035 mg EE. The subjects were divided into 3 groups on the basis of their histories of OC use. Ten had not taken an OC in the previous 2 months, 10 were switched to this study from a fixed-dosage combination OC containing 0.050 mg estrogen, and 9 had been taking ORTHO 7/7/7 Tablets for 5 or more cycles. Serum levels of FSH, LH, estradiol and progesterone were measured and statistically compared with those from 5 normal, untreated women. The results from all study cycles showed that the four hormone profiles were significantly suppressed as compared to the normal patterns. Thus, one mode of action of this new triphasic OC is to inhibit ovulation by suppression of pituitary-ovarian function. This OC treatment appeared to be equally effective among women with varying prior histories of OC therapy.

Adult↗