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Biomedical subjects

P N Prinz

Publications and source records attributed to P N Prinz.

At least 55 records · Page 3Linked to original sources
PubMed1985

Age-related changes in venous catecholamines basally and during epinephrine infusion in man.

Plasma epinephrine (EPI) and norepinephrine (NE) levels were examined among healthy men aged 20 to 25 and 60 to 65 years basally and during EPI infusions. On separate days, 14.3 and 42.9 ng/kg/min EPI was administered intravenously for 45 min. Although there was no age difference in venous EPI levels basally, the old had less increase during the EPI infusions. The plasma metabolic clearance rate of EPI was greater among the old men. Plasma NE levels were elevated among the elderly men, but both age groups had an increase in NE during the EPI 42.9 ng/kg/min infusion rate. During EPI infusions, the old men had less increase in systolic but not diastolic blood pressure or heart rate compared with the young men. The different pattern of change in venous EPI levels and increased metabolic clearance rate of EPI observed among the old men could, in part, explain diminished end-organ responsivity.

Adult↗
PubMed1984

The clinical utility of the dementia rating scale for assessing Alzheimer patients.

Community residing patients with mild (n = 18) or moderately severe (n = 16) Alzheimer's disease and controls (n = 23) were given Mattis' Dementia Rating Scale (DRS) and a brief measure of confrontation naming selected from the Boston Naming Test (BNT). The DRS was shown to be a reliable and clinically useful measure of mental status in patients with Alzheimer's disease. The DRS subscales and the BNT had excellent internal consistency reliabilities and the total DRS score (TDRS) was shown to be generally unrelated to gender and education. Among the dementia patients, performance on the TDRS was significantly associated with functional competence. The two dementia samples had similar profiles on the DRS and BNT, with the mild subjects performing significantly better than the moderately severe subjects on each measure. Extending the range of DRS subscales would improve this measure's utility as an evaluation instrument.

Activities of Daily Living↗
PubMed1984

Circadian temperature variation in healthy aged and in Alzheimer's disease.

Circadian temperature variation was monitored in healthy older adults and in health-, age-, and sex-matched Alzheimer's dementia patients. Oral and rectal temperatures were analyzed for mean level, amplitude, and phase using cosinor analyses. Mean 24-hour temperature level was not altered by dementia. A significant sex effect, however, was observed among dementia patients with women exceeding men in mean 24-hour temperatures and across daytime time periods. Cosinor-derived phase and amplitude measures were unaffected by dementia or by sex. This indicates that the primary neuronal degeneration characteristic of Alzheimer's disease in its early stages does not disable the neural pathway(s) controlling circadian temperature regulation. Some impairment in temperature homeostatic regulation may be present, however, because a greater intrasubject temperature variability was observed in Alzheimer men than in control men.

Age Factors↗
PubMed1984

Memory, attention, and functional status in community-residing Alzheimer type dementia patients and optimally healthy aged individuals.

This paper reports the results of two studies. Investigation I examined patterns of cognitive performance in healthy controls and mildly-to-moderately impaired patients with senile dementia of the Alzheimer type (SDAT). Investigation II focused on the degree to which cognitive test scores could predict functional competence in SDAT patients. The samples included 23 controls, 18 mildly impaired SDAT, and 16 moderately impaired SDAT patients. Cognitive measures included tests of attention, calculation, recognition memory, recall, and orientation. The functional competence measures included maintenance, communication, and recreational abilities. Investigation I found that the patterns of attention and memory that distinguish control from mildly impaired SDAT patients differ from those that distinguish mildly from moderately impaired SDAT patients. Investigation II found that it is possible to predict behavioral competence in individuals with dementia from a knowledge of their attentional and memory deficits.

Activities of Daily Living↗
PubMed1984

Plasma norepinephrine in normal young and aged men: relationship with sleep.

This study explored the relationship between age-related elevations of plasma norepinephrine (NE) levels (thought to reflect heightened sympathetic nervous system activity) and sleep. Plasma NE levels were consistently and significantly greater in 8 aged than 10 young men across a 24-hr study period. For both groups, plasma catecholamine levels remained stable near bedtimes and rise times and during spontaneous and experimentally induced nighttime awakenings; reversal of the sleep/wake pattern (nighttime wakefulness, daytime sleep) had little effect on the 24-hr plasma NE or sleep patterns, indicating that elevated NE cannot be attributed to altered sleep/wakefulness per se. The aged group had significantly more wakefulness and significantly higher plasma NE levels while in bed in all study conditions. These two variables were significantly correlated, suggesting that heightened sympathetic activity may fragment sleep with wakefulness in the aged.

Adult↗
PubMed1984

Rapid eye movement sleep measures of Alzheimer's-type dementia patients and optimally healthy aged individuals.

It has been suggested that rapid eye movement (REM) sleep measures may be useful in the differential diagnosis of affective disorders. To determine what changes, if any, of REM measures occur in Alzheimer's dementia we examined the REM sleep of nine control and nine mild, nine moderate, and nine severe dementia subjects with probable Alzheimer's disease (AD). Control and mild and moderate AD groups were screened to exclude major depression. REM latency, REM time, REM activity, and REM density were examined. Results indicated that REM sleep measures are minimally affected by mild dementia. None of the REM sleep variables reported here successfully discriminated mild AD subjects from controls. However, REM time and REM latency were significantly affected in later stages of dementia. Total time in REM and REM latency successfully classified control and moderate-severe AD patients. In addition, the pattern of REM density across the night was also affected by severity of dementia. The results of this study, when compared to published REM measure findings in major depression, indicate that with proper cautions REM sleep measures may prove useful in the differential diagnosis of dementia and depression in geriatric patient populations.

Aged↗
PubMed1983

Plasma growth hormone during sleep in young and aged men.

Plasma growth hormone measured at 20-min intervals across the night via indwelling venous cannula revealed a significant reduction in 16 healthy aged men as compared with 14 healthy young men. The decrease in growth hormone was entirely confined to the first 3 hours of the night (M +/- SEM for the integrated level was 5.0 +/- 1.2 and 21 +/- 4.2 ng . hr/ml). Growth hormone across the latter part of the night did not differ. Day and evening growth hormone levels measured hourly in five of the aged and nine of the young men failed to reveal an age effect. Growth hormone release is known to be associated with sleep onset, and particularly with slow wave sleep, stage 3 and 4, which was reduced in amount in these aged men (9.9 +/- 1.9 and 22.8 +/- 2.3% of time in bed for aged and young groups, respectively). Sleep stage 3 and 4 correlated significantly with growth hormone level (R = .463, p less than .01) for young and aged men combined, but not for either age group alone, indicating that growth hormone does not have a direct, simple relationship with slow wave sleep.

Adult↗
PubMed1983

Sleep apnea: relationship to age, sex, and Alzheimer's dementia.

The relationship of sleep apnea to age, sex, and Alzheimer's dementia was investigated in 45 elderly subjects and 10 young males, all nonobese, normotensive, nonsmoking, with no sleep complaints and no medical problems other than Alzheimer's disease. Mean apnea/hypopnea index [(AH)I] was significantly greater in elderly males than in young males or elderly females. Mean (AH)I and percentage of subjects with an (AH)I greater than 5 in the Alzheimer groups were not significantly different from age and sex-matched controls. Results were similar when the apnea index was substituted for (AH)I. The data from this preliminary study indicate that healthy, elderly males with no sleep complaints and elderly males with Alzheimer's disease experience a significant, subclinical ventilatory impairment during sleep. Data from the 10 elderly females and 10 young males indicated no such impairment. The physiological significance of this degree of sleep apnea in otherwise healthy elderly males is unclear at present.

Adult↗
PubMed1983

Sodium-restricted diet increases nighttime plasma norepinephrine and impairs sleep patterns in man.

Plasma norepinephrine levels in 10 healthy young males were significantly elevated after 3 days of a low sodium (less than 500 mg/day) diet. The low sodium diet was also associated with disturbed sleep patterns: decreased rapid eye movement and slow wave sleep and increased wakefulness. These sleep changes are similar to those seen in normal aged adults, who also undergo elevations of daytime and nighttime plasma norepinephrine. These results suggest the possibility that increased sympathetic nervous system activity may affect sleep patterns, and that therapies altering sympathetic activity may affect sleep.

Adult↗
PubMed1983

Loss of circadian rhythmicity in blood testosterone levels with aging in normal men.

Previous studies concerning the relationship of serum testosterone levels to aging in normal men have yielded apparently inconsistent results. Studies performing blood sampling in the morning have often shown an age-related decrease in testosterone levels, while those using afternoon samples have failed to show such a decrease. These results suggested to us the possibility that the circadian rhythm in serum testosterone levels might be altered with normal aging in men. Hourly blood samples were obtained for 24 h from 17 young (mean age, 25.2 yr) and 12 old (mean age, 71 yr) healthy men. Total testosterone levels were measured by RIA. The circadian rhythm in serum testosterone levels found in normal young men was markedly attenuated or absent in healthy elderly men; the early morning rise in testosterone levels characteristic of young men was not present in old age. Mean testosterone levels for the entire 24-h day were lower in healthy old men than in young men. These results demonstrate a clear decrease in serum testosterone levels in healthy old men compared to those in young men and provide an explanation for the inability to demonstrate an age-related decline in testosterone levels in earlier studies using serum samples obtained in the afternoon.

Adult↗
PubMed1982

Sleep, EEG and mental function changes in senile dementia of the Alzheimer's type.

Sleep, EEG and mental function variables were studied in 44 subjects diagnosed as having probable senile dementia of the Alzheimer's type (SDAT) and 22 controls matched for age and minimal depression. Results indicate that sleep, EEG and mental function variables all undergo significant change even in the early, mild stage of SDAT, with further change in the moderate and severe stages of dementia. Mental function variables also underwent significant decline across levels of dementia. Sleep and mental function variables had strong power in correctly classifying subjects into control vs. mild dementia groups (90 and 100%, respectively). Dominant occipital rhythm frequency, a clinical EEG measure, also discriminate as well (75%). The results indicate that sleep and EEG variables discriminate well for early, mild SDAT in minimally depressed aged individuals.

Aged↗
PubMed1982

Changes in the sleep and waking EEGs of nondemented and demented elderly subjects.

Sleep and waking EEGs from 11 healthy nondemented elderly men and from ten inpatients for whom the diagnosis was probable senile dementia of Alzheimer's type (SDAT), were monitored in the subjects' typical home or ward environments or in the sleep laboratory, according to their customary sleep schedules. Aged normal subjects (age range, 56-85 years) had less Stage 3 and Stage 4 sleep, less REM sleep, and more wakefulness than normally observed in young adults. Patients with SDAT (age range, 56-88 years) had even less Stage 3 sleep, no Stage 4 sleep, and very little REM sleep, and experienced fragmentation of their sleep, with frequent awakenings. These sleep variables were significantly different in the SDAT and control groups (MANOVA). Examination of the 24-hour plots of sleep/waking patterns revealed prominent fragmentation of the diurnal sleep/waking rhythm in SDAT patients, with frequent daytime napping and nighttime periods of wakefulness. In addition, significant group differences were observed for the EEG variable, dominant occipital frequency. More qualitative EEG variables (diffuse slowing, spindle activity, and paroxysmal discharges) also differed between groups. It is suggested that correlative neuropathologic data might provide an understanding of the basis for the sleep, EEG, and mental-function factors that undergo change in SDAT.

Aged↗
PubMed1981

Dementia and other competing risks for mortality in the institutionalized aged.

The relative importance of dementia, gender, age and functional status (FS) was examined for relationships to mortality within five years after admission of the subjects to a New York City nursing home for the aged. Using a random sample of 212 of the nursing home's patients, a statistical model was developed to estimate the relative risk of mortality. When this model was cross-validated on an independent sample of 118 residents, it failed to show significant lack of fit. Given these results, an international model was developed by combining the New York City samples(N = 330) and comparing them to a sample (N = 363) from a nursing home in Tokyo, Japan. In the new York model, gender was the most important predictor, with age and dementia next in importance; FS was not a significant predictor. Despite the apparent differences in the types of dementia in the New York and Tokyo nursing homes, the mortality patterns were similar.

Age Factors↗
PubMed1981

Effect of phenobarbital on sleep and nighttime plasma growth hormone and cortisol levels.

The acute and chronic effects of phenobarbital and phenobarbital withdrawal on sleep patterns and on plasma growth hormone (GH) and cortisol fluctuations occurring during sleep were studied. Before bed, five healthy men, aged 21 to 25, were given a placebo on three baseline nights, phenobarbital (100 mg p.o.) for nine nights, and a placebo on a final withdrawal night. Beginning on the third of three consecutive nights in the laboratory, all-night polygraphic sleep recordings and blood samples (obtained every 20 min through indwelling venous cannulae) were collected for the placebo, acute phenobarbital, chronic phenobarbital, and phenobarbital withdrawal conditions. Blood phenobarbital levels ranged between 5 to 9 micrograms/100 mL across all hours of the chronic drug night. At this low sedative dose, latency to sleep onset and stage 4 sleep were significantly reduced in the chronic drug condition, but REM sleep was not significantly reduced. No significant sleep change was observed on the withdrawal night. Both peak GH level and total integrated GH across the night were unaffected by the acute, chronic, and withdrawal conditions. The pattern of GH release appeared to be altered on the phenobarbital and phenobarbital withdrawal nights as compared with placebo. Nighttime plasma cortisol levels were not significantly altered by any experimental condition.

Adult↗
PubMed1980

Effect of alcohol on sleep and nighttime plasma growth hormone and cortisol concentrations.

The acute and chronic effects of alcohol and alcohol withdrawal on sleep patterns and plasma GH and cortisol fluctuations occurring during sleep were studied. Five healthy men, aged 21-26 yr, consumed a placebo drink for 3 baseline nights, alcohol (0.8 g/kg) for 9 nights, and a placebo drink on final withdrawal night. All-night polygraphic sleep recordings and blood samples (every 20 min with a venous catheter) were collected for 1 placebo, 1 acute alcohol, 1 chronic alcohol (night 9), and 1 alcohol withdrawal night. Acute and chronic alcohol consumption reduced rapid eye movement sleep nonsignificantly during the first half of the night, whereas slow wave sleep (stages 3 and 4) was increased significantly after acute alcohol, returning to baseline values on the chronic alcohol night. On the withdrawal night, rapid eye movement sleep and slow wave sleep were not significantly different from placebo sleep. Alcohol significantly suppressed plasma GH values (70-75%) on acute and chronic nights. All measures of GH, including total integral for bedtime hours, mean hourly rate, and peak level, were similarly affected by alcohol. GH returned to placebo values on the withdrawal night. Measures of nighttime plasma cortisol were not significantly altered by alcohol or alcohol withdrawal at this dose level.

Adult↗
PubMed1979

Circadian variation of plasma catecholamines in young and old men: relation to rapid eye movement and slow wave sleep.

Young and old healthy subjects with indwelling venous cannulae were found to undergo significant diurnal variations in plasma catecholamine levels. Both norepinephrine and epinephrine levels peaked in late morning and reached lowest values at night during sleep. Catecholamine levels were similar during slow wave and rapid eye movement sleep. While epinephrine levels were unaffected by age, norepinephrine levels were greater in older subjects by 28% during the day (at 1100 h; P less than 0.01) and by 75% at night (between 2200--0900 h; P less than 0.01). Older subjects slept less well; they had 90% less stage 4 sleep, 27% less rapid eye movement sleep, and twice as much wakefulness at night (P less than 0.05). These findings raise the possibility that this well known age effect on sleep may be related to increased sympathetic nervous system activity.

Adult↗