Components of Type A Behavior and Task-Induced Cardiovascular Activation

The present study sought to determine whether there are subcomponents of the Type A behavior pattern that are more closely related to cardiovascular reactivity than others. The components studied were factor analytically derived subscales of the Jenkins Activity Survey denoting Irritation and Impatience, on the one hand, and Hard-Driving and Competitive, on the other. Heart rate, pulse transit time, forearm electromyography, and palmar skin conductance were measured while the subjects performed a continuous perceptual motor task, as well as during baselines before and after the task. The Irritation and Impatience dimension was consistently related to task-induced changes in heart rate, both in regression analyses and in extreme group analyses of variance. A significant relation was also observed for pulse transit time but not for electromyography. The Hard-Driving and Competitive dimension, on the other hand, was not related to any psychophysiological measures. These results were interpreted to mean that Irritable and Impatient subjects showed a cardiovascular reaction pattern indicative of active coping processes during task performance.     

Hemispheric Asymmetry and Human Classical Conditioning to Verbal and Non-Verbal Visual CSs

A new paradigm called “the dichoplic acquisition paradigm” was developed to study Ihc effects of hemispheric asymmetry on classical etcctrodcrmal conditioning. The paradigm involves three phases: 1) A habituation phase where two different color-words written in two incongruent colors are tachistoscopically displayed bilaterally to the visual half-fields left and right of center fixation; 2) An acquisition phase, wherein the display is followed by a 105dB white noise on each trial; and 3) An extinction phase, where each of the four CS cues (two color-words and two colors) are separately presented bilaterally for simultaneous input to both hemispheres. Here the color-words are now presented in grey against a black background, and the colors as color-bars against the same background. A control group had no UCS presentations. Bilateral skin conductance responses (SCRs) of right-handed males were used to evaluate conditioning. Conditioning to the CS color-word previously presented in the right half-field (i.e. initial left-hemisphere input) during acquisition led to larger SCRs during extinction, than the color-word previously presented in the left half-held (i.e. initial right-hemisphere input). In contrast, the CS color cue previously presented in the left half-field during acquisition resulted in larger SCRs during the first extinction trial, than the CS color cue previously presented in the right half-field. Thus, the present experiment revealed effects of hemispheric asymmetry on human electrodermal conditioning.     

Creatine kinase BB in blood as index of prognosis and effect of treatment after severe head injury

Summary High concentrations of creatine kinase BB (CK-BB) were found in all blood samples drawn within 6 hours of accident from 45 patients with brain contusion. The highest concentrations of more than 100 microg/1 were measured in blood samples taken shortly after the accident from patients with a Glasgow Coma Score (GCS) of 6 or less.The CK-BB concentrations decreased rapidly to normal within 36 hours of accident in the patients given intensive care guided by intracranial pressure (ICP) monitoring. In patients with less severe injuries according to GCS the initial CK-BB concentrations were generally lower and normalized less rapidly. The outcome after 6 months was moderate or good in all 9 patients who had this rapid normalization of blood CK-BB. On the other hand, of 20 patients who had a more slow CK-BB decrease, only 9 had an acceptable outcome.Delayed ICP increase to more than 40 mm Hg and even delayed brain tamponade did not result in CK-BB levels higher than 5 microg/1. Brain tamponade in the acute stage resulted in rapid CK-BB decrease in the blood.In paired simultaneously drawn samples of lumbar cerebrospinal fluid (CSF) and blood, CK-BB levels were generally higher in the CSF.Hans-Kristian Nordby is a fellow of the Norwegian Research Council for Science and Humanities.     

Mild essential hypertension in nonobese premenopausal women is characterized by low renin.

The pathophysiological mechanisms in hypertension may differ in men and women. Plasma renin activity was measured in 27 premenopausal, never-treated hypertensive women (blood pressure 141 +/- 2/93 +/- 1 mm Hg) and in 18 age-matched normotensive women (blood pressure 113 +/- 2/71 +/- 2 mm Hg). All subjects were unaware of their blood pressure status. The hypertensive women had on average lower plasma renin activity (0.21 +/- 0.03 nmol/L/h) than their normotensive controls (0.42 +/- 0.07 nmol/L/h, P less than .01). Serum estradiol was also lower in the hypertensive women (0.57 +/- 0.06 v 0.81 +/- 0.09 nmol/L, P less than .05). No difference in epinephrine, norepinephrine, atrial natriuretic peptide, or vasopressin was found between the groups. Plasma renin activity was positively correlated to plasma norepinephrine in the hypertensive women only (r = 0.41, P less than .05). Since low renin hypertension is associated with less cardiovascular complications, this may offer an explanation for the better prognosis of hypertension in women.     

Anticipatory nausea and vomiting in cancer patients.

The present study reports on a mediating mechanism for anticipatory nausea and vomiting (ANV) in cancer chemotherapy. ANV is usually explained as a classically conditioned response. However, conditioning models have failed to explain individual variation in ANV susceptibility. On the basis of the positive correlation between degree of autonomic reactivity (AR) and conditionability, it is proposed that individual AR is predictive of ANV development. Of the 31 patients who participated in the study, 74% experienced postinfusion nausea and vomiting (PNV). Of the 23 patients who experienced PNV, 52% developed ANV. AR was recorded in a habituation paradigm before chemotherapy treatment was initiated. The patients in the ANV group showed significantly increased sympathetic reactivity as compared with the no-ANV group, implying that AR is a mediator of ANV development.     

The dependence of the sporicidal effects on the power and pressure of RF-generated plasma processes

The sporicidal effect of 20 different radio-frequency plasma processes produced by combining five different gas mixtures [O(2), Ar/H(2) (50/50%), Ar/H(2) (5/95%), O(2)/H(2) (50/50%), O(2)/H(2) (95/5%)] with four power/pressure settings were tested. Sporicidal effects of oxygen-containing plasmas were dependent on power at low pressure settings but not at high pressure settings. In the absence of oxygen no power dependency was observed at either high or low pressure settings. Survivor curves obtained with the use of nonoxygen plasmas typically had a tailing tendency. Only a mixture-optimized Ar/H(2) (15/85%) plasma process was not encumbered by tailing, and produced a decimal reduction time (D value) below 2 min for Bacillus stearothermophilus spores. Scanning electron microscopy showed that a CF(4)/O(2) plasma did more damage to the substrate than the 15/85% Ar/H(2) plasma. The present results indicate that UV irradiation inactivation is swift and power and pressure independent. Additionally, it is produced at low energy. However, it is not complete. Inactivation through etching is highly power and pressure dependent; finally, inactivation by photodesorption is moderately power and pressure dependent. A sterilization process relying on this mechanism is very advantageous because it combines a highly sporicidal effect with low substrate damage.     

The diagnostic value of measuring creatine kinase BB activity in cerebrospinal fluid following acute head injury

Summary During a period of 2 months the activity of creatine kinase BB (CK-BB) was measured in the cerebrospinal fluid (CSF) from 93 consecutive patients admitted as emergencies to the Neurosurgical Department.Fourteen of the 15 patients with verified brain contusion showed an increased activity of CK-BB in the CSF whereas all patients with various other acute neurological disorders, such as epilepsy and acute headache, had a normal CK-BB activity. Two of 5 patients with subarachnoidal haemorrhage and 13 of 58 patients classified as concussion also showed an increased CK-BB activity. Spinal fluid pressure, number of red cells and activity of CK (total) were less useful than CK-BB in diagnosing acute brain damage. Even diagnostic ventricular puncture with a Fisher cannula, producing a tiny (diameter=2.8 mm) brain lesion, gave rise to an increased CK-BB activity.CSF sampled repeatedly from 10 other patients with brain contusion showed CK-BB activities that suggest the optimum period for sampling to be between one and 15 hours after head injury. The results obtained suggest that CK-BB is a reliable indicator of brain damage following head injury.Petter Urdal is a fellow of the Norwegian Research Council for Science and Humanities.     

The prognosis of patients with concussion and increased creatine kinase BB in the cerebrospinal fluid

Summary In a series of 93 emergency patients, 58 were classified as concussions on a clinical basis. Thirteen of the patients with concussion had increased levels of creatine kinase isoenzyme BB (CK-BB) in their cerebrospinal fluid (CSF). We performed a prospective, follow-up investigation comparing 10 patients with a CK-BB increase and 10 patients without a CK-BB increase after concussion.Within 24 hours, at 6 months and 3 years after concussion, each patient was subject to a special interview to obtain pre-concussional baseline data and post-concussional follow-up data concerning their complaints and capacity for daily activities. We found a definite change towards increasing disability in 8 of the 10 patients with a raised CK-BB, and in only 1 of the 10 patients with normal levels of CK-BB. A careful neuropsychological examination confirmed inferior performance in tests especially sensitive to brain injury in patients with a CK-BB increase.Our results suggest that increased levels of CK-BB after concussion signify a more severe injury which is not found in the clinical examination during the first days after the accident, and that these patients are a high-risk group for the development of post-concussional problems and symptoms.     

Safety incidents associated with extended working hours. A systematic review and meta-analysis

Objective:We performed a systematic review to assess potential consequences of extended working hours on accidents, near-accidents, safety incidents and injuries (hereafter ’incidents’) by considering the overall certainty of evidence.Methods:We searched five databases systematically (Medline, Embase, PsycINFO, Web of Science, and Proquest Health and Safety Science Abstracts) and identified 10 072 studies published up to December 2020, 22 of which met the inclusion criteria. We followed a systematic approach to evaluate risk of bias and synthesize results in a meta-analysis. The certainty of evidence was determined by a modified version of the Grading of Recommendations Assessment, Development and Evaluation (GRADE).Results:Our analyses indicated an association between working >12 hours/day [relative risk (RR) 1.24, 95% confidence interval (CI) 1.11–1.40], or working >55 hours/week (RR 1.24, 95% I 0.98–1.57), and elevated risk of incidents. The certainty of evidence evaluated as low. Weak or no associations were observed for other exposure contrasts: working >8 hours/day (RR 0.93, 95% CI 0.72–1.19), or working overtime (RR 1.08, 95% CI 0.75–1.55), working 41–48 hours/week (RR 1.02, 95% CI 0.92–1.13) or 49–54 hours/week (RR 1.02, 95% CI 0.97–1.07). The certainty of evidence was evaluated as low (very low for 41–48 hours/week).Conclusions:Daily working hours >12 hours and weekly working hours >55 hours was associated with an increased risk of incidents. The certainty of evidence was low. Hence, further high-quality research is warranted to elucidate these associations.