Glial membrane potentials and their relationship to [K+]o in man and guinea pig. A comparative study of intracellularly marked normal, reactive, and neoplastic glia.
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Animals↗
Biomedical subjects
C F Pieper
Publications and source records attributed to C F Pieper.
Comparative study of cerebral cortical potentials associated with voluntary movements in monkey and man.
Eight monkeys (Macaca mulatta) were taught to squeeze and release a handgrip. The movement simulated the brisk squeeze of a hand dynamometer performed by 7 human subjects. Monkey. During the performance of the voluntary movements, slow cortical potentials (motor potentials or MPs) were studied with monopolar, surface bipolar, transcortical and intracortical recordings. A survey of the dorsal expanse of cerebral cortex showed that the contralateral motor hand area, somatosensory hand area and area 6 adjacent to the supplementary motor area became active with movement. MPs also were seen in the motor and somatosensory cortex medial to the hand area, but we concluded that those potentials were probably related to adventitious movements in the arm and leg. That area 6 became active with movement was further verified with extracellular unit recording; the behavior of area 6 units was compared with that recorded from units in the motor hand area. Using simultaneous transcortical recordings a sequence of cortical activation was observed in those areas generating an MP. The motor hand area became active first, followed in turn by area 6 and the somatosensory hand area. The monosynaptic cortico-cortical connections of the motor hand area were studied with autoradiographic and horseradish peroxidase techniques and compared to the distribution of the MP. The hand area demonstrated reciprocal connectivity with portions of the somatosensory hand area, the supplementary motor area in area 6 and the cortex adjacent to the intraparietal sulcus. The distribution of the MPs correlated with the connectivity to the supplementary motor and somatosensory areas. Our physiologic studies did not adequately investigate the area adjacent to the intraparietal sulcus. Man. Motor potentials were studied using surface bipolar recordings with closely spaced electrodes (inter-electrode distances 1 cm or 2 cm). Recordings were made directly from the cortex in one subject studied under local anesthesia during an operation for epilepsy, and epidurally in 6 subjects in whom epidural electrode arrays had been inserted for the purpose of localizing an epileptogenic focus. Similar to the findings in the animals, MPs were recorded from the contralateral motor and somatosensory hand area with activity in motor cortex appearing first; area 6 just anterior to the motor hand area probably also generated a response. In addition, a locally generated potential not seen in monkey was recorded anterior to area 6. This difference in response distribution is viewed as possibly relating to the different significance which the seemingly comparable hand movements have for the animal and human subjects. No response was seen in motor and somatosensory hand area with ipsilateral movements. We have no information for the anteriorly recorded response with ipsilateral movement.
Animals↗
Caffeine and cholesterol: interactions with hostility.
The consumption of caffeinated beverages has been linked to elevated serum cholesterol and an increased risk of coronary disease, although the relationships are inconsistent across studies and remain controversial. The effect of caffeine on cholesterol and coronary disease risk may be modulated by other factors. Using cohort data from a subsample of the University of North Carolina Alumni Heart Study, we investigated whether the relationships between caffeinated beverage consumption and serum lipid and lipoprotein levels in middle-aged men and women were modulated by levels of trait hostility. After adjustment for other risk factors, higher caffeinated beverage intake was associated with higher low-density lipoprotein cholesterol levels and a higher ratio of total to high-density lipoprotein cholesterol, both indicative of greater coronary disease risk. The interactive effects of hostility and caffeine intake were ambiguous, although there were trends for caffeine intake to have stronger effects on low-density lipoprotein and on total cholesterol in people with less hostility. Additional studies of personality characteristics and other factors that can modulate the cholesterol-raising effects of coffee drinking may be warranted because they might clarify the health consequences associated with coffee drinking and lead to the identification of individuals who would benefit most from changes in their coffee drinking.
Adult↗
Caffeine raises blood pressure at work.
OBJECTIVE: The study investigated the effects of moderate doses of caffeine on ambulatory blood pressure and heart rate during workday activities. METHODS: Healthy, nonsmoking, habitual coffee drinkers (N = 21) received daily doses of 100 mg and 500 mg of caffeine on 2 days in a crossover design. Treatment order was random and counterbalanced, and administration was double-blind. Ambulatory monitoring was conducted for 6 to 9 hours during normal workday activities and diary entries were completed at each measurement. Ambulatory data were analyzed for the effects of caffeine dose, controlling for variations in posture, physical activity, and perceived stress. RESULTS: The average workday blood pressure and heart rate were significantly higher when the higher dose of caffeine was consumed. Controlling for other factors, dose-related differences were 4 mm Hg for systolic and 3 mm Hg for diastolic blood pressure, and were 3 bpm for heart rate. CONCLUSIONS: Results support earlier evidence that caffeine raises blood pressure at work, and demonstrate that these pressor effects are independent of changes in posture, physical activity, or stress. Daily blood pressure increases associated with caffeine consumption could increase the risk of developing cardiovascular diseases. In addition, caffeine consumption effects might confound ambulatory investigations of the cardiovascular effects of other psychosocial, personality, or health-behavior factors.
Adult↗
The perceived racism scale: a multidimensional assessment of the experience of white racism among African Americans.
The experience of racism is a complex, multidimensional phenomenon. At present, there are few instruments that attempt to capture the experience of racism in all of its complexity. For this study, a new instrument, the Perceived Racism Scale, has been constructed to assess the experience of racism in African Americans in a multidimensional manner. The scale not only provides a measure of the frequency of exposure to many manifestations of racism (including individual and institutional, overt and covert, attitudinal, behavioral, and cultural), but takes a step forward in more comprehensively measuring the experience of racism by assessing emotional and behavioral coping responses to racism. These responses are measured with respect to exposure to racism in three situational domains: on the job, in academic settings, and in the public realm. Measurement of responses to a fourth domain, that of exposure to racist statements, is also included. It is hoped that the Perceived Racism Scale will facilitate a more comprehensive understanding of the experience of racism among African Americans and, through its use in research and clinical settings, will ultimately move us closer to reducing the prevalence and potentially untoward effects of racism.
Adaptation, Psychological↗