A comparison of neurotoxicity in cerebellum produced by dermal application of chlorpyrifos in young and adult mice.

Chlorpyrifos (CPF), an organophosphate pesticide inhibits acetylcholinesterase (AChE) and causes neuromuscular incoordination among children and elderly. The objectives of the present study were to compare the neurotoxic effects of dermal application of CPF on the cerebellum in the parameters of glial fibrillary acidic protein (GFAP) expression in young and adult mice and to correlate with the changes in acetylcholinesterase levels. Male Balb/c mice, 150 days old (adult) and 18 days old (young) were dermally applied with ½ LD(50) of CPF over the tails for 14 days. Serum AChE concentration was estimated and GFAP immunostaining was performed on sagittal paraffin sections through the vermis of cerebellum. Although reduced in both age-groups exposed to CPF, percentage of reduction in serum AChE was more in adult compared to the young. Under GFAP immunostaining, brown colour fibres and glial cells were observed in cerebellar cortex and medulla in both the experimental groups. The mean GFAP-positive glial cell count in cerebellar medulla per mm(2) of section was significantly (p < 0.05) increased in adult mice exposed to CPF when compared with age-matched control. In conclusion, this study confirmed that dermal exposure of CPF was able to exert neurotoxic effect in both young and adult mice. However, the quantitative results revealed that adult mice showed more GFAP expression in cerebellum when compared with the young, when exposed to CPF.

A validation study of the instromedix Baro-Graf QD home blood pressure monitor.

The purpose of this study was to assess the accuracy of the Instromedix Baro-Graf QD home blood pressure monitor. Forty subjects were divided among three blood pressure (BP) groups: low (BP less than 110/70, N = 11); medium (BP 110/70 to 140/90, N = 17) and high (BP greater than 140/90, N = 12). Five seated readings were taken per subject. We examined the differences between simultaneous auscultatory and machine readings and assessed the machine's accuracy using ANOVA and correlation analysis. The results show that the device, while highly accurate, tended to become less so as pressure increased. However, its accuracy was superior compared to most other devices we have tested, and because of features, such as a computer memory that stores events and blood pressure over time, this monitor will likely be a useful tool for clinical trials of long term blood pressure change.

Winter-summer differences in the effects of emotion, posture and place of measurement on blood pressure.

The purpose of this study was to assess whether the effects of emotional state, posture, situation of measurement, and sex on daily blood pressure variation were different in subjects measured during summer months (May-September) and winter months (November-March). The subjects of the study were 157 patients from the Hypertension Center of New York Hospital-Cornell Medical Center in New York, who had ambulatory blood pressure monitoring performed between February 1984 and April 1985. Individual pressures taken with the monitor over the day in each subject were transformed to z-scores using the subject's daily mean pressure and standard deviation in order to assess differences in intraindividual variation. The zeta-scores were examined in separate but identical analyses of variance models (one for the winter months and one for the summer months) which included emotional state (happy, angry, anxious), posture (sitting, standing), situation of measurement (home, work, elsewhere) and sex as factors. The results showed that more factors had greater effects (as reflected in R2) on blood pressure during the winter months than summer months. In particular, the relative effect of anxiety, sitting, and being at work or home on blood pressure was significantly greater (P less than 0.05) in the winter months than summer months. In addition, pressure elevation during happiness was also more accentuated in winter than summer for diastolic pressure (P less than 0.05). These findings may have important implications for the interpretation of population studies examining the relationship between blood pressure and psychosocial stressors.

The reproducibility of average ambulatory, home, and clinic pressures.

The reproducibility of ambulatory, home, and clinic blood pressures was compared in 13 untreated mildly hypertensive and 14 normotensive subjects. Each subject had two sets of daily ambulatory recordings, home self-measured readings (over 6 days), and clinic measurements taken 2 weeks apart. Comparisons over the 2 weeks within and among the methods of measurements were made using a repeated-measures analysis of variance. The results showed that there was no consistent average change in the ambulatory or home pressures and no change in clinic diastolic pressures, but the clinic systolic pressure of the hypertensive subjects dropped 6 mm Hg (p less than 0.05), while that of the normotensive subjects showed no significant change. Test-retest correlations of each of the three methods were similar in magnitude, indicating a similar level of reliability. Test-retest correlations of the ambulatory standard deviations, however, were low, indicating a low reliability of this measure of daily pressure variability. These results suggest that the reproducibility of ambulatory pressures may be as good or better than that of home or clinic measurements. They also suggest that the average ambulatory pressure may be preferable as the measurement in clinical trials, since it may be less influenced by measurement anxiety, particularly in hypertensive subjects.

Do laboratory tests of blood pressure reactivity predict blood pressure changes during everyday life?

This study was undertaken to examine whether blood pressure reactivity measured in the controlled setting of a laboratory could be correlated with blood pressure changes occurring during daily life. The subjects were 164 untreated hypertensives with mild hypertension, all of whom had a 24-hour ambulatory blood pressure recording, during which their activities were unrestricted. One hundred thirteen performed a treadmill exercise test, and 51 performed two active coping tasks (playing a video game or mental arithmetic). Blood pressure was monitored at baseline and during the tasks. Significant correlations were observed between the absolute levels of pressure measured during the laboratory tests and ambulatory monitoring, but these were higher for the active coping tasks (r = 0.53 to 0.75) than the exercise testing (r = 0.26 to 0.46) and were no higher for pressures measured during the tasks than at baseline. Correlations between the changes of blood pressure during the laboratory tasks and the changes occurring during ambulatory monitoring were analyzed in three ways, using simple, multiple, and canonical correlations. In no case were these correlations substantively significant. We conclude that blood pressure reactivity measured in the laboratory may not be readily generalized to changes of pressure in everyday life, as measured by noninvasive ambulatory recorders.

Sex differences in factors affecting the daily variation of blood pressure.

The purpose of this study was to examine whether the life experiences described by postural, situational, and emotional changes during the day have similar effects on the blood pressure of men and women. The subjects of the study were 137 men and 67 women from the clinical population of the Hypertension Center at The New York Hospital-Cornell Medical Center. There were 3023 individual pressure measurements available for study, 2072 from the men, and 951 from the women, which were taken using noninvasive ambulatory blood pressure monitoring techniques. Pressures were transformed to z-scores using the subject's daily mean pressure and standard deviation to assess the relative elevation during the various effects. Separate but identical ANOVA models were run for each sex. The results show that there were differences between men and women in the parameters associated with the level of systolic and diastolic pressure. Men's systolic pressure varied by situation of measurement (P less than 0.0001) and emotional state (P less than 0.0001), while that of women varied by posture (P less than 0.0005) and situation of measurement (P less than 0.0001). The diastolic pressure of men varied by emotional state as did that of women, except that men's diastolic pressure tended to be highest during reported anger while that of women tended to be highest during reported anxiety. Differences in occupation or environment, hormones, or in behavioral patterns related to the socialization process may all contribute to the differences between the sexes.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of happiness, anger, and anxiety on the blood pressure of borderline hypertensives.

Differences in blood pressure associated with reported happiness, anger, and anxiety are examined among 90 borderline hypertensives during 24-hr blood pressure monitoring. There were 1152 individual ambulatory blood pressure readings for which subjects classified their emotional state as happy (n = 628), angry (n = 67), or anxious (n = 457) on scales from one (low) to ten (high). Pressures were transformed to z-scores using the subject's 24-hr mean and standard deviation to assess relative elevation during reported emotional arousal. The results show that emotional arousal significantly increases systolic and diastolic pressure (p less than 0.00001), an effect independent of posture and location of subject during measurement (at work, home, or elsewhere). On average, pressures during reported angry or anxious states were higher than those during a happy state (p less than 0.01). Examination of arousal intensity showed that scores on the happiness scale were inversely related to systolic pressure (p less than 0.01) whereas the degree of anxiety was positively associated with diastolic pressure (p less than 0.02). Emotional effects were also related to the degree of individual daily pressure variation such that the greater the variability, the larger the blood pressure change associated with the emotions. The results suggest that happiness, anger, and anxiety increase blood pressure to differing degrees and that emotional effects may be greater in individuals with more labile blood pressure.