The cold pressor test: Vascular and myocardial response patterns and their stability

The purposes of the present study were to compare the cardiovascular response patterns evoked by three versions of the cold pressor test (either forehead stimulation or hand or foot immersion) and to determine the reproducibility of the responses over a 2-week interval. Blood pressure, heart rate, stroke volume, cardiac output, total peripheral resistance, and systolic time intervals were obtained during rest and during the cold pressor test in 42 young men. Across conditions, the pressor response was supported by peripheral resistance increases with concomitant stroke volume decreases. Although the response panerns were generally similar across sites, exceptions were apparent for heart rate. Forehead stimulation was characterized by no significant change in heart rate, whereas limb (hand or foot) immersion was associated with significant heart rate acceleration. The responses elicited by the three cold pressor test conditions were reliable and showed little evidence of attenuation over the test-retest interval.     

Detection of Human Heart Rate in Exercises State

作者介绍了一种动态心率检测电路，它能准确、可靠地检出在运动状态下的人体心率。电路采用两种检测技术，一种为双时值ＱＲＳ波检测法，另一种为光电脉搏检测法。     

A 5-year retrospective analysis of employer-provided dental care for Finnish male industrial workers

Abstract The treatment-mix, treatment time, and dental status of 268 male industrial workers entitled to employer-provided dental care were studied. The data were collected from treatment records of the covered workers over the 5-year period 1989-93. Treatment time was based on clinical treatment time recorded per patient visit, and the treatment procedure codes were reclassified into a treatment-mix according to American Dental Association categories, with a modification combining endodontics and restorative treatment. The mean number of check-ups followed by prescribed treatment (treatment courses) during the 5 years was 3.7 among those who had entered the in-house dental care program prior to the monitored period (old attenders). Their treatment time was stable, 57–63 min per year, while the first-year mean treatment time (170 min) of those who had entered the program during the study period (new attenders) was significantly higher (P<0.01) than the 5-year mean of the old attenders (61 min). Over the first 2 years, the treatment-mix of the new attenders showed a rise in diagnostic and preventive procedures from one-third to about one-half of all procedures, as it was for the old attenders. The new attenders' mean number of carious teeth (2.7), registered at the initial check-up visit, paralleled the mean recently demonstrated in the similar non-covered population. It was significantly higher than the 5-year mean of the old attenders (0.5) (P<0.001), but declined to the same level after the first year of treatment. It was concluded that the studied program seemed to contribute to a stabilization of treatment-mix, and to the establishment of a shorter annual treatment time within the first 2 years of treatment.     

Stimulation of nerve growth factor and substance P expression in the iris–trigeminal axis of diabetic rats—involvement of oxidative stress and effects of aldose reductase inhibition

In rats with streptozotocin-induced diabetes, we measured increased (by 61%; P<0.05) mRNA for nerve growth factor (NGF) in the iris together with increased (by 82%; P<0.05) mRNA for preprotachykinin (the substance P precursor) in the trigeminal ganglion, suggesting that increased NGF was driving increased substance P gene expression. In other diabetic rats, these changes were prevented by treatment with either an antioxidant (butylated hydroxytoluene; 1% by diet) or an aldose reductase inhibitor (ARI) (sorbinil; 25 mg/kg/day p.o.) and the sorbinil treatment was associated with significant inhibition of polyol pathway intermediates in both lens and sciatic nerve. This suggests that polyol pathway activity in the lens may translate to oxidative stress-driving stimulation of NGF gene expression in the iris. The change is selective for NGF, because expression of the analogous neurotrophin, neurotrophin-3 (NT-3), was unaltered in the same irises. These changes suggest that oxidative stress and/or inflammation can drive up NGF expression in diabetes—a mechanism that might participate in iritis.     

STRESS IN THE RURAL EMERGENCY ROOM

ABSTRACT: This study identifies stress-producing factors reported by registered nurses (RNs) attending serious incidents in an Australian rural hospital's emergency room. A Delphi approach was used to determine the six most significant stress-producing factors, and these factors were then ranked by two groups of nurses. The rankings were compared using the Spearman Rank Order Coefficient of Correlation and were found to be dependent on years of nursing experience of the RNs taking part in the study. The more experienced group nominated 'anxiety about nursing a family member or close friend' as the most significant stress-producing factor, while the less experienced group reported 'concerns about nursing a child' as the most important stress-producing factor. Possible reasons for the variation in rankings are discussed, and recommendations are made in the light of the study's findings.     

Post-traumatic stress disorder among the injured of theintifada

The current study aimed to assess the prevalence of PTSD among Palestinians who sustained serious bodily injuries during theintifada, as well as to delineate factors having an effect on the development and attenuation of PTSD symptomatology. Results indicated evidence of high prevalence of PTSD among the injured. No significant differences in PTSD prevalence for demographic, situational, and trauma-related variables were found except for the age factor. Prevalence of PTSD among adolescents was significantly higher than among adults. It seemed that the injury itself was so intensely overwhelming that the other variables were overshadowed. Implications for further research and stress management techniques were discussed.     

A critical survey of hypotheses regarding Post-traumatic Stress Disorders in light of recent research findings

This paper reviews briefly recent findings from psychobiological research upon Post-traumatic Stress Disorders. A critical assay is provided of the various hypotheses advanced as the result of this research data. The author suggests neuropsychological theory provides the best explanation for understanding and classifying both the clinical phenomenology and the biological abnormalities discovered in the chronic forms of PTSD.Initial draft presented at a workshop Delayed Effects of Post Traumatic Stress Disorders, sponsored by the Emergency Services Branch of the National Institutes of Mental Health April 14–15, 1986.     

Biological responses to overload training in endurance sports

Summary Five subjects undertook 10 days of twice daily interval training sessions on a treadmill followed by 5 days of active recovery. On days 1, 6, 11, and 16 the subjects were required to undertake a test of submaximal and maximal work capacity on a treadmill combined with a performance test consisting of a run to exhaustion with the treadmill set at 18 km · h^–1 and 1% gradient. Also on these days a pre-exercise blood sample was collected and analysed for a range of haematological, biochemical and immunological parameters. The subjects experienced a significant fall in performance on day 11 which had returned to pretraining levels on day 16. Serum ferritin concentrations were depressed significantly from pretraining concentrations at the conclusion of the recovery period while the expression of lymphocyte activation antigens (CD25⁺ and HLA-DR⁺) was increased both after the training phase and the recovery phase. The number of CD56⁺ cells in the peripheral circulation was depressed at the conclusion of the recovery period. Several parameters previously reported to change in association with overload training failing to reflect the decrease in performance experienced by subjects in this study, suggesting that overtraining may best be diagnosed through a multifactorial approach to the recognition of symptoms. The most important factor to consider may be a decrease in the level of performance following a regeneration period. The magnitude of this decreased performance necessary for the diagnosis of overtraining and the nature of an appropriate regeneration period are, however, difficult to define and may vary depending upon the training background of the subjects and the nature of the preceding training. It may or may not be associated with biochemical, haematological, physiological and immunological indicators. Individual cases may present a different range of symptoms and diagnosis of overtraining should not be excluded based on the failure of blood parameters to demonstrate variation. However, blood parameters may be useful to identify possible aetiology in each separate case report of overtraining. An outstanding factor to emerge from this study was the difficulty associated with an objective diagnosis of overtraining and this is a possible reason why there have been new accounts of overtraining research in the literature.     

Five different tests of reaction time evaluated in HIV seropositive men

In an attempt to develop a short neuropsychological test battery five different tests of reaction time were assessed according to their ability to discriminate between HIV seropositive men and healthy controls. In all tests a patient group with clinical symptoms was slower than the control group. In the complex reaction time test, which has a large cognitive aspect, even a clinically "asymptomatic" group was slower than the control group. The movement test, a new test with a large motor component, identified most slow responders, defining approximately half of the patients with clinical symptoms and one third of the "asymptomatic" patients as such. A test battery consisting of three tests is suggested for serial assessment and screening.     

Intramuscular pressure,EMG and blood flow during low-level prolonged static contraction in man

Seven men performed one-legged isometric knee-extension at 5% MVC for 1 h. Intramuscular pressure increased with contraction from its resting value of 14 (2–31) mmHg. Some intramuscular pressure recordings stayed at an almost constant level throught the 1 h contraction, but most recordings showed large fluctuations from resting values up to 90 mmHg. The overall mean intramuscular pressure was twice the resting value. In some cases, EMG recordings confirmed that the changes in intramuscular pressure were related to alternating recruitment of various parts of the knee-extensors. Blood flow in the femoral vein increased within 3 min of 5% MVC to a level of 1.58 (1.25-2.22) 1 min^-1 and no significant changes occurred during the 1 h contraction. In two subjects blood flow was measured also in the recovery period, and this decreased almost immediately when the muscle relaxed. It is concluded that during low-level static contractions, the blood supply to the exercising muscle is maintained at a sufficiently high level, and that the alternating recruitment of muscle fibres may result in a heterogeneously distributed blood flow within the contracting muscle. Despite this the muscle was fatigued after the 1 h at 5 % MVC. The rating of perceived exertion (RPE) increased from 1.9 (1–3) at the beginning to 4.5(2–8) at the end of contraction, and MVC was decreased by 12% after the contraction.