Biomedical subjects
Publications and source records attributed to C B Taylor.
Plasma lipids were measured in 102 subjects with panic disorder or agoraphobia. In women, but not men, a significantly higher than expected number of subjects had cholesterol values that exceeded the 75th percentile of national reference values for their sex and age.
The lifetime prevalence of interview-determined four-symptom panic attacks in 95 ninth graders was 11.6%. Those with panic attacks were significantly more depressed, were significantly more likely to have separated or divorced parents, and tended to be more likely to have tried cigarette smoking.
Twenty patients with panic attacks and ten controls were given a standardised interview about thoughts occurring during times of anxiety or panic attacks. The interviewer was blind to the subject's diagnosis. The 20 panic patients underwent a psychophysiological test battery which included a cold pressor test, mental arithmetic task, and 5.5% CO2 inhalation. More patients than controls reported thoughts centered on fears of losing control and shame when anxious. Panic patients rated their thoughts as stronger and clearer than did controls and they had more difficulty excluding them from their minds. A feeling of anxiety preceded anxious thoughts in patients. This suggests that 'faulty cognitions' are not the initial event in a panic attack, although anxious thoughts may exacerbate or maintain them. Significant correlations were found between the intensity of anxiety-related thoughts in anticipation of mental arithmetic and changes in diastolic blood pressure and heart rate during mental arithmetic.
To determine if an occupational work evaluation could shorten the time to return to work, 201 employed men aged 49 +/- 7 years who were recovering from uncomplicated myocardial infarction were randomized to usual care (n = 102) or to an occupational work evaluation (n = 99). The occupational work evaluation consisted of a symptom-limited treadmill test performed 23 +/- 3 days after myocardial infarction and a formal recommendation to the patient and primary physician that the patient return to work within the next two weeks. The groups did not differ in age, medical status, comorbid disease, occupation type, or years on the job. At six months, 92% of patients receiving the intervention and 88% of patients receiving usual care were working either full- or part-time. Return to full-time work occurred at a median of 51 days in patients receiving the intervention and 75 days in patients receiving usual care. This 32% reduction in the convalescence period was associated with +2102 of additional earned salary per intervention patient in the six months after myocardial infarction. One or more recurrent cardiac events occurred in 14 intervention patients (one death, one nonfatal myocardial infarction, three angioplasties, and nine coronary surgeries) and in 13 usual-care patients (two deaths, three nonfatal myocardial infarctions, six angioplasties, and seven coronary surgeries) in the six months after myocardial infarction. The early return to work of low-risk patients based on an occupational work evaluation is associated with important economic benefits.
Two studies were undertaken to compare strategies for the adoption and maintenance of moderate-intensity, home-based exercise training. In the study of adoption, 52 men and women who had served for 6 months as controls for a study of moderate-intensity, home-based exercise training received 30 minutes of baseline instruction. They were then randomized to receive continuing instruction and support through 10 staff-initiated telephone contacts of 5 minutes each every 2 weeks, or to receive no telephone contacts. In subjects receiving telephone contacts, peak oxygen uptake increased significantly after 6 months, whereas no increase was observed in subjects receiving no staff support (p less than 0.05). In the maintenance study, 51 men and women who had significantly increased their peak oxygen uptake by 6 months of moderate-intensity, home-based exercise training were randomized to undergo daily self-monitoring and receive adherence instructions, or undergo weekly self-monitoring only, during a second 6-month period of training. Subjects performing daily self-monitoring reported completing significantly more exercise training sessions during the 6 months of training than subjects performing weekly self-monitoring; functional capacity in both groups remained higher than before training (p less than 0.05). Taken together, these studies suggest that brief baseline instruction followed by continuing telephone contact with staff can be used to help people adopt a moderate-intensity, home-based exercise training program that can be maintained by simple self-monitoring strategies.
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Twenty-three patients meeting DSM-III criteria for agoraphobia with panic attacks and 14 age-, race-, and sex-matched nonanxious controls were tested in the laboratory and on a test walk in a shopping mall. The patients were tested before and after about 15 weeks of treatment with placebo and exposure therapy, imipramine and exposure therapy, or imipramine and initial antiexposure instructions. Controls were tested twice at a similar interval, but without any treatment. On test day 1, patients compared to controls showed higher average heart rate and skin conductance levels and greater numbers of skin conductance fluctuations in the laboratory, and higher heart rates before and during the test walk. Between pretreatment and posttreatment tests, clinical ratings improved and skin conductance levels decreased in all treatment groups. Heart rate levels in the laboratory, on the other hand, decreased in patients on placebo and rose in patients on imipramine. Thus, imipramine compromises the usefulness of heart rate as a measure of emotional arousal. Higher pretreatment heart rates predicted greater clinical improvement.
Personality theorists have long predicted a relationship between personality traits and autonomic activation. In this study, 48 patients with panic disorder underwent personality assessment by questionnaire (Eysenck Personality Inventory: 48 patients) and by interview (Personality Disorders Examination: 35 patients). Ambulatory heart rate and activity were measured by the Vitalog method and were used as measures of activation and autonomic arousal. There was a significant positive correlation between histrionic traits and activity level and a significant negative correlation between sociability and heart rate. The findings are consistent with previous studies showing a negative relationship between sensation-seeking personality traits and cerebrospinal fluid levels of norepinephrine and a positive relationship between extroversion and cerebrospinal fluid levels of dopamine.
To determine the influence of exercise training on smoking after acute myocardial infarction (AMI), smoking rates in 42 pre-AMI smokers assigned to exercise training were compared with 26 pre-AMI smokers assigned to no training. Exercise training occurred 3-26 weeks after AMI. The increase in functional capacity in 3-26 weeks was significantly greater in training than in no-training patients: 1.8 vs. 1.2 METs respectively (p less than 0.05). Adherence to exercise training was higher in non-smokers and former smokers than in those who continued to smoke: 89% and 88% vs. 80% respectively (NS). The prevalence of smoking 6 months post-AMI was lower in training than in no-training patients: 31% vs. 39% respectively (NS). Plasma thiocyanates collected on a random sample of 42 patients suggested that 19% of patients who are smoking after MI fail to report doing so. Self-reported cigarette consumption at 28 weeks was half as great in training as in no-training patients: 11 +/- 7 vs. 22 +/- 16 cigarettes per day (p less than 0.03). Firm advice to stop smoking followed by medically supervised exercise training with frequent followup reduces self-reported cigarette consumption in patients after AMI.
This experiment tested the hypothesis that perceived self-inefficacy in exercising control over cognitive stressors activates endogenous opioid systems. Subjects performed mathematical operations under conditions in which they could exercise full control over the cognitive task demands or in which the cognitive demands strained or exceeded their cognitive capabilities. Subjects with induced high perceived self-efficacy exhibited little stress, whereas those with induced low perceived self-efficacy experienced a high level of stress and autonomic arousal. Subjects were then administered either an inert saline solution or naloxone, an opiate antagonist that blocks the analgesic effects of endogenous opiates, whereupon their level of pain tolerance was measured. The self-efficacious nonstressed subjects gave no evidence of opioid activation. The self-inefficacious stressed subjects were able to withstand increasing amounts of pain stimulation under saline conditions. However, when endogenous opioid mechanisms that control pain were blocked by naloxone, the subjects were unable to bear much pain stimulation. This pattern of changes suggests that the stress-induced analgesia found under the saline condition was mediated by endogenous opioid mechanisms and counteracted by the opiate antagonist.
The nature of the stromal cells in formalin-fixed paraffin-embedded material from 23 cerebellar haemangioblastomas was investigated using antisera to intermediate filaments (glial fibrillary acidic protein, vimentin and desmin), histiocytic markers (alpha 1-antitrypsin, alpha 1-antichymotrypsin and lysozyme), glycolytic enzymes (alpha and gamma enolase and aldolase C4) and the endothelial markers, factor VIII related antigen and Ulex europaeus I lectin. Most stromal cells stained positively for vimentin and the glycolytic enzymes. Occasional process-bearing cells within the stroma stained strongly for glial fibrillary acidic protein, alpha 1-antitrypsin and alpha 1-antichymotrypsin. No stromal cell staining for desmin, lysozyme or the endothelial markers was observed, although the latter stained the vascular endothelium within all neoplasms. The findings do not support previous suggestions of an endothelial or histiocytic origin for the stromal cells. They appear to be a heterogeneous population including entrapped reactive astrocytes and locally-derived non-angiogenic cells of neuroectodermal (pial) origin.
Treadmill exercise test performance and ambulatory heart rate and activity patterns of 40 patients with panic attacks were compared with 20 age-matched controls (control group 1) and 20 nonexercising controls (control group 2). All patients underwent a symptom-limited exercise stress test. Panic attack patients and control group 1 wore an ambulatory heart rate/activity monitor for up to 3 days. Panic patients had a significantly higher heart rate at 4 and 6 METS than either control group. The max METS were 11.2 +/- 2.3, 13.5 +/- 2.3 and 11.2 +/- 1.8 for the panic attack patients and control groups 1 and 2, respectively. One panic patient had ischemia on the treadmill at 12 METS. Panic patients had a significantly higher standing heart rate than controls. Furthermore, 11 of 39 panic patients had tachycardia on standing compared with 3 of 40 controls. Panic attack patients had higher wake and sleep heart rates than control group 1, but the differences were not significant. These results are consistent with autonomic dysfunction in panic patients but may also be due to differences in physical conditioning. The treadmill can be useful for reassuring patients and for identifying the rare patient with ischemia on exercise.
We asked 1447 tenth graders to complete a survey on physical activity, nutrition, stress, and substance use and to undergo basic physical assessments. In a multiple regression analysis, increased level of substance use by both boys and girls was most strongly predicted by friends' marijuana use. For boys, this was followed by perceived safety of cigarette smoking; poor school performance; parents' education; and use of diet pills, laxatives, or diuretics for weight control, accounting for 44% of the overall variation in substance use. For girls, friends' marijuana use was followed by poor school performance; self-induced vomiting for weight control; perceived safety of cigarette smoking; use of diet pills, laxatives, or diuretics for weight control; parents' education; perceived adult attitudes about cigarettes; and nonuse of seat belts, accounting for 53% of the overall variance. Separate multiple regression analyses for each substance produced similar results. The homogeneity of the study population precluded ethnic comparisons. These findings suggest that for many purposes substance use may be considered a single behavior regardless of the specific substance(s) used and that substance use may exist as part of a syndrome of adolescent problem behaviors. In addition, the potent influence of perceived social environment suggests that a social influence resistance model may represent the most successful preventive strategy.
Using a radio-immunoassay, aldolase A and B isoenzyme concentrations have been measured in the sera of patients in order to assess their specificity and sensitivity in a variety of hepatic disorders. Serum aldolase A has been confirmed to be elevated in some patients with malignant infiltration of the liver, but its sensitivity is not sufficient to be of clinical value. Aldolase B is a sensitive marker of liver cell damage which correlates closely with conventional biochemical markers of inflammation. It appears to distinguish successfully between hepatic and cardiac damage.
The effects of 6 months of self-monitored, home-based exercise training on maximal oxygen uptake (VO2 max), body composition and plasma lipid levels of healthy, sedentary, middle-aged persons were evaluated in 60 men, aged 49 +/- 6 years, and 60 women, aged 47 +/- 5 years. Moderate-intensity training was performed 5 times per week in sessions of 47 +/- 7 minutes and 54 +/- 8 minutes for men and women, respectively. The individually prescribed range of heart rate corresponded to 65 to 77% of the peak value during symptom-limited treadmill testing (mean of 72% for men and 69% for women). Caloric expenditure per training session was approximately 345 kcal for men and 235 kcal for women. VO2 max increased 15% in men and 9% in women (both p less than 0.01). The greater increase in VO2 max in men than in women primarily reflected greater adherence to training in men (greater than or equal to 90% vs greater than or equal to 75%). The increase in VO2 max in women who showed very high adherence was comparable to that of men. Body weight decreased, by 1.5 +/- 10 kg, in men (p less than 0.05) but not in women undergoing training. No significant training-induced changes in plasma lipid levels were noted in either men or women. Baseline orientation and follow-up telephone calls required less than 1 hour of staff time per participant. Self-monitored, moderate-intensity, home-based exercise training significantly increases functional capacity in healthy, middle-aged men and women. Such training provides an alternative to group-based exercise training.
Research in exercise training of healthy persons, which has been conducted almost exclusively in supervised group programs, is relatively expensive for the investigator and inconvenient for the participant. To overcome these obstacles, self-monitored moderate-intensity home-based exercise training was prescribed for 28 middle-aged men and 26 middle-aged women. The median energy expenditure prescribed for each of 5 weekly exercise sessions was 4 cal/kg body weight, or 317 kcal for men and 265 kcal for women, corresponding to a median duration of 45 and 60 minutes, respectively. In the next 24 weeks, peak oxygen uptake increased 13.7% in men who exercised, from 31 +/- 4 to 37 +/- 4 ml/kg/min, and 10% in women who exercised, from 26 +/- 4 to 29 +/- 5 ml/kg/min (p less than 0.001 for both comparisons). The proportion of prescribed caloric expenditure per session, which was documented by a solid-state heart rate recorder, was 108% in men and 90% in women. The duration of training at heart rates above the prescribed range approximated 10 minutes per session for both men and women; the proportion of total caloric expenditure represented by exercise at heart rates exceeding the prescribed limit was 9% for men and 4% for women. The proportion of time spent within the prescribed heart rate range during training sessions was 76% for men and 84% for women. Training-induced musculoskeletal problems were reported by 6 men and no women. No subject sought medical attention and all resumed training within 1 week.(ABSTRACT TRUNCATED AT 250 WORDS)
In this experiment, we tested for opioid and nonopioid mechanisms of pain control through cognitive means and the relation of opioid involvement to perceived coping efficacy. Subjects were taught cognitive methods of pain control, were administered a placebo, or received no intervention. Their pain tolerance was then measured at periodic intervals after they were administered either a saline solution or naloxone, an opiate antagonist that blocks the effects of endogenous opiates. Training in cognitive control strengthened perceived self-efficacy both to withstand and to reduce pain; placebo medication enhanced perceived efficacy to withstand pain but not reductive efficacy; and neither form of perceived self-efficacy changed without any intervention. Regardless of condition, the stronger the perceived self-efficacy to withstand pain, the longer subjects endured mounting pain stimulation. The findings provide evidence that attenuation of the impact of pain stimulation through cognitive control is mediated by both opioid and nonopioid mechanisms. Cognitive copers administered naloxone were less able to tolerate pain stimulation than were their saline counterparts. The stronger the perceived self-efficacy to reduce pain, the greater was the opioid activation. Cognitive copers were also able to achieve some increase in pain tolerance even when opioid mechanisms were blocked by naloxone, which is in keeping with a nonopioid component in cognitive pain control. We found suggestive evidence that placebo medication may also activate some opioid involvement. Because placebos do not impart pain reduction skills, it was perceived self-efficacy to endure pain that predicted degree of opioid activation.
The present study examined the effectiveness of a community-based smoking contest in helping 500 smokers maintain three months postcontest and one year postcontest abstinence. The majority were chronic smokers with a limited number of previous quit attempts. The three- and 12-month postcontest quit rates were 19 per cent and 15 per cent, respectively, rates exceeding naturally occurring community cessation rates. The contest was found to be more cost-effective than quit smoking classes.