Serum lipids and vitamin A, C and E concentrations in an adult population of Caracas City

OBJECTIVES: Event-related desynchronization (ERD) and synchronization (ERS) of the 8-10 and 10-12 Hz frequency bands of the background EEG were studied in 10 subjects performing an auditory lexical matching task. METHODS: The stimuli were words and pseudowords presented sequentially in pairs. The subject was prompted to answer whether the two stimuli shared the same lexical status (words or pseudowords). RESULTS: Regardless of lexicality, the presentation of the first stimulus elicited a significant late frontal ERD in both alpha frequency bands. When preceded by a pseudoword, the presentation of the second stimulus elicited a significant ERS at 200-400 ms and a significant, long-lasting and topographically-widespread ERD at 600-2200 ms in both frequency bands. When preceded by a word, the second stimulus did not elicit ERS in the initial time window, but a late ERD which was similar to the one observed in the previous condition. The complexity of ERD/ERS changes in the present task was revealed by significant interactions that time had with frequency band, stimulus type, stimulus order and lexicality of the preceding stimulus. CONCLUSIONS: The results suggest that ERD/ERS does not reflect primary auditory stimulus processing. Rather, the ERD/ERS observed in this experiment most probably reflected task difficulty and differences between lexical-semantic and phonological memory functions.     

Relation between fat intake and mortality: an ecological analysis in Belgium

To understand the role of the motor cortex in implicit and explicit learning, we studied alpha event-related desynchronization (ERD) while 13 right-handed individuals performed a variation of the serial reaction time task (SRTT). EEG signals were recorded simultaneously from 29 scalp locations and the ERD was computed. During data collection, all subjects developed implicit knowledge, demonstrated by shortening of the response time, and explicit knowledge of the test sequence. The average ERD maps of all 13 subjects demonstrated that during the initial learning, there was a decline in alpha band power that was maximal over the contralateral central region. The ERD reached a transient peak amplitude at a point when the subjects attained full explicit knowledge, and diminished subsequently. The transient peak in ERD was highly significant at C3. These electrophysiologic findings support previous studies which have demonstrated that motor activity changes as behavior changes over the course of learning.     

Electrophysiological, behavioral, and subjective indexes of workload when performing multiple tasks: manipulations of task difficulty and training

This study examined whether alpha event-related desynchronization (ERD) and theta event-related synchronization (ERS) could successfully measure changes in cognitive workload and training while an operator was engaged in a continuous, interactive, control task(s). Alpha 1 (8-10 Hz) ERD, alpha 2 (10-12 Hz) ERD, and theta (3-7 Hz) ERS were determined for a communications event that occurred during multiple task workload conditions or as a single task. Other measures (alpha and theta EEG power, heart rate, respiration, eye blinks, behavioral performance, and subjective workload ratings) were also evaluated. Results showed that alpha 2 EEG, heart rate, behavioral, and subjective measures were sensitive to changes in workload in the multiple tasks. In addition, eye blink rate and behavioral measures were sensitive to training. Alpha ERD and theta ERS were not sensitive to workload and training in our interactive, multiple task environment. However, they were effective indexes of cognitive/behavioral demands within an interactive single task.     

Prenatal psychosocial stress exposure is associated with subsequent working memory performance in young women.

The aim of the present study was to examine the association between prenatal psychosocial stress exposure and subsequent prefrontal cortex-dependent working memory performance in human adults. Working memory performance was assessed using an item-recognition task under 10 mg hydrocortisone (cortisol) and placebo conditions in a sample of 32 healthy young women (mean age = 25 ± 4.34 years) whose mothers experienced a major negative life event during their pregnancy (Prenatal Stress, PS group), and in a comparison group of 27 healthy young women (mean age = 24 ± 3.4 years). The two groups did not differ in the placebo condition, however, subjects in the PS group showed longer reaction times after hydrocortisone administration compared with subjects in the comparison group (p = .02). These findings provide support for an association between prenatal stress exposure and the potential modulatory effect of cortisol on working memory performance in young adults, which may reflect compromised development of the prefrontal cortex in prenatal life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The dynamic nature and age-related dependence of functional brain organization in attention

Intrahemispheric functional organization was studied during a task expectancy period with special reference to attention mechanisms. The estimation of coherence of functionally identical rhythmic EEG components was made to characterize the intracortical integration. Several factors influencing the possibility to make an adequate prognosis and to realize it were varied. Different types of the task were used. Subjects of different age (7, 9-10 years, young adults) and children of the same age differing by the brain maturity level were under study. It was shown that all factors studied have certain influence on the brain organization underlying the task preceding attention. Clear age differences as well as the lag between the possibility to formation and realization the prognosis in children were observed. Alternative "strategies" used in different ages to facilitate the task performance were analysed; underlying mechanisms were discussed.     

Aging and the scope of visual attention

OBJECTIVE: To discover whether some cognitive deficits associated with aging could be related to a restricted scope of visual attention. DESIGN: Cross-sectional study, with subjects in each age group receiving the same four conditions. Subjects: 24 elderly (mean age 65.2 years, 12 men and 12 women) and 24 young (mean age 21.8 years, 12 men and 12 women) matched for handedness, gender, and education level. METHODS: Subjects viewed a display that contained four light-gray squares arranged as if on the tips of a plus sign, then black X marks appeared and the subjects indicated whether one or two Xs appeared in the squares as quickly and accurately as possible. The time to respond and accuracy level were recorded. Two types of displays were used; one with squares spread out over a large area and one with squares condensed into a small area. In two thirds of the trials the size remained the same (with half being large, and half small), and in one third it changed (with half of these trials changing from large-to-small and half from small-to-large). RESULTS: In the trials that had a consistent display size, the elderly subjects performed the task better with the smaller display, whereas the young subjects performed equally well with both sized displays. In addition, the elderly found it easier to shift from large to small scope than to maintain attention at the large scope; in contrast, the younger subjects found it easiest to maintain attention on a static display size. CONCLUSIONS: The elderly prefer to focus attention on a smaller region of space than do younger people.     

In vitro and in vivo antibacterial activities of TOC-50, a new parenteral cephalosporin, against Enterococcus faecalis

The object of the study was to compare resting pupil diameter in darkness and light, and the pupillary darkness and light reflexes between a group of young and elderly healthy subjects. Twelve young (eight men, four women; median age 19.5 years) and 14 elderly subjects (six men, eight women; median age 69 years) participated. Pupil diameter was monitored with an infra-red television pupillometer. Resting pupil size was measured in light (16 and 32 Cd m-2) and in darkness. The darkness reflex was elicited by switching off the ambient illumination (16 Cd m-2) for 1 s. The light reflex was elicited in darkness by short (200 ms) pulses of green (peak wavelength 565 nm) light at four ascending stimulus intensities (8.5 x 10(-3), 7.0 x 10(-2), 0.43 and 1.84 mW cm-2). The amplitude (mm) and maximum velocity (mm s-1) of the darkness reflex and the latency (ms), amplitude (mm), maximum constriction velocity (mm s-1) and 75% recovery time (s) of the light reflex were measured. The resting pupil diameter was found to be smaller in the elderly group at all three illumination levels (p = 0.001). The amplitude and maximum dilatation velocity of the darkness reflex were smaller for the elderly group (p = 0.001). The amplitude of the light reflex at the three highest light intensities and maximum constriction velocity at all light intensities were smaller in the elderly group (p = 0.002). Seventy-five per cent recovery time was longer in the elderly group (p = 0.02). There was no difference in the latency of the light reflex response between the two groups. The reduced pupil size, diminished darkness reflex amplitude and velocity, and prolonged recovery time of light reflex are consistent with sympathetic deficit in old age. Although the reductions in light reflex amplitude and constriction velocity in the elderly group at first sight would indicate a parasympathetic deficit in old age, they are more likely to be secondary to the grossly diminished pupil size.     

The effects of handedness and type of movement on the contralateral preponderance of mu-rhythm desynchronisation

Event-related desynchronisation (ERD) of mu-rhythm was studied in 12 right-handed and 11 left-handed subjects during brisk and slow self-paced index finger movements of dominant and nondominant hand. Electroencephalogram (EEG) was recorded from the sensorimotor hand area of both hemispheres. The contralateral preponderance of mu-rhythm ERD in the pre-movement period showed the following changes: (i) the contrasts between left- and right-finger movements were larger and earlier in the dominant than nondominant hemisphere in both handedness groups; (ii) right-handed subjects showed larger lateralisation of mu-rhythm ERD prior to right-finger as compared to left-finger movements, whereas about equal contralateral preponderance for both sides was found in the left-handed; (iii) the lateralisation of mu-rhythm ERD was lower prior to brisk as compared to slow movements, especially in the left-handed subjects. The results demonstrate that hand dominance, handedness and type of movement influence the proportion of pre-movement mu-rhythm desynchronisation in the left and right peri-rolandic area.     

Workplace smoking policies in the United States: results from a national survey of more than 100,000 workers

To investigate the activity of cortical regions in the control of movement, we studied event-related desynchronization/synchronization (ERD/ERS), event-related coherence (ERC), and phase coherence in 29-channel EEGs from 9 subjects performing self-paced movements of the right index finger. Movement preparation and execution produced ERD over the sensorimotor areas at 10 Hz and 20 Hz, followed by ERS. ERD corresponded spatiotemporally to an increase in coherence over the frontocentral areas. For both frequency bands, ERD began over the left sensorimotor areas and became bilateral at the time of movement onset. The coherence increase with frontal areas began in the left central areas and became symmetrical after EMG onset. The ERD and coherence increase was longer at 10 Hz than at 20 Hz. Phase coherence at 10 Hz showed a lead of anterior regions to posterior regions throughout the time period, and at 20 Hz showed a tendency toward zero phase delay corresponding with the movement. EEG desynchronization parallels functional coupling over sensorimotor and frontal areas. Event-related coherence and phase coherence findings implicate the frontal lobes in control of movement planning and execution. The involvement of different frequency bands with different timings may represent parallel changes in the cortical network.     

Cortisol secretion is related to electroencephalographic alertness in human subjects during daytime wakefulness

To determine whether human hypothalamo-pituitary-adrenal axis activity is related to the alertness level during wakefulness, 10 healthy young men were studied under resting conditions in the daytime (0900-1800 h) after an 8-h nighttime sleep (2300-0700 h). A serial 70-sec gaze fixation task was required every 10 min throughout the daytime experimental session. The corresponding waking electroencephalographic (EEG) segments were submitted to quantitative spectral analysis, from which EEG beta activity (absolute power density in the 13-35 Hz frequency band), an index of central alertness, was computed. Blood was collected continuously through an indwelling venous catheter and sampled at 10-min intervals. Plasma cortisol concentrations were measured by RIA, and the corresponding secretory rates were determined by a deconvolution procedure. Analysis of individual profiles demonstrated a declining tendency for EEG beta activity and cortisol secretory rate, with an overall temporal relationship indicated by positive and significant cross-correlation coefficients between the two variables in all subjects (average r=0.565, P < 0.001). Changes in cortisol secretion lagged behind fluctuations in EEG beta activity, with an average delay of 10 min for all the subjects. On the average, 4.6+/-0.4 cortisol secretory pulses and 4.9+/-0.5 peaks in EEG beta activity were identified by a detection algorithm. A significant, although not systematic, association between the episodes in the two variables was found: 44% of the peaks in EEG beta activity (relative amplitude, near 125%; P < 0.001) occurred during an ascending phase of cortisol secretion, cortisol secretory rates increasing by 40% (P < 0.01) 10-min after peaks in EEG beta activity. However, no significant change in EEG beta activity was observed during the period from 50 min before to 50 min after pulses in cortisol secretion. In conclusion, the present study describes a temporal coupling between cortisol release and central alertness, as reflected in the waking EEG beta activity. These findings suggest the existence of connections between the mechanisms involved in the control of hypothalamo-pituitary-adrenal activity and the activation processes of the brain, which undergoes varying degrees of alertness throughout daytime wakefulness.     

The effects of sleep loss on task performance and the electroencephalogram in young and elderly subjects

The effects of 28-h sleep loss on performance, reaction time (RT) distribution functions, and spectral composition of the EEG were evaluated in three choice-RT tasks for young (N = 12, aged 18-24 years) and old (N = 12, aged 62-73 years) subjects. Manipulations of stimulus degradation, stimulus-response compatibility, and interstimulus interval variability were to affect encoding, response selection, and motor adjustment stages, respectively. In order to discriminate between independent variables that were presumed to be computational or energetical in nature, effects on EEG spectra and RT-distributions were studied. Spectra of the EEG indicated higher cortical arousal levels for the elderly than for the young. The most dramatic effect of sleep loss on performance was a marked increase in the number of omitted responses. This effect was smaller for the elderly than for the young. The results suggest that the detrimental effects of sleep loss are smaller in the elderly, which is consistent with an inverted-U relationship between arousal and performance. The age effects on the processing stages were mainly limited to response selection.     

Haemodynamic and renal effects of felodipine in young and elderly subjects

OBJECTIVE: To study the influence of age on renal and haemodynamic effects of the calcium antagonist felodipine. METHODS: Eight young (mean age 27 years) and eight elderly (mean age 75 years) healthy normotensive subjects were given felodipine intravenously for 120 min aiming at close to therapeutic plasma level concentration. Renal blood flow (RBF) and renal vascular resistance (RVR) was estimated from para-aminohippuric acid (PAH) clearance 51CrEDTA clearance was used to measure glomerular filtration rate (GFR) and used in the calculations of fractional excretion (FE) of electrolytes. Impedance cardiography was performed to assess stroke volume and for the calculation of cardiac output and ejection fraction. RESULTS: At the end of felodipine infusion, the concentration of felodipine was on average 10.0 nmol x l(-1) in young and 12.0 nmol x l(-1) in elderly subjects (NS). During felodipine infusion blood pressure (BP) decreased from 138/76 to 120/68 in elderly subjects. The BP in young subjects was 126/74 at basal and 125/70 after infusion of felodipine. The systemic and renal vascular resistance decreased to a similar extent in young and elderly subjects after felodipine infusion. Felodipine caused a decrease in systemic vascular resistance from 25.6 to 23.3 in elderly and from 23.8 to 21.8 in the young subjects. Mean values for RVR at baseline and during infusion of felodipine were significantly higher in the elderly (10.1-15.1) than in the young subjects (5.4-6.7). Felodipine reduced RVR by 10% in the young and by 12% in the elderly at the end of infusion. The young subjects had 31% higher GFR than the elderly subjects at the start of infusion. Felodipine infusion did not affect GFR. There were no effects on stroke volume and ejection fraction. An initial natriuretic effect was found after infusion of felodipine in the young subjects. The fractional excretion of all electrolytes tended to increase after both felodipine and placebo, more in the elderly than in the young subjects. CONCLUSION: The effects of felodipine on central and renal haemodynamics previously observed in young and middle-aged subjects also seem to exist in the elderly. Volume expansion seems to increase the excretion of electrolytes more in elderly than in young people, and therefore the effect of felodipine on natriuresis is more evident in young subjects.     

The influence of age on the assessment of motor unit activation in a human hand muscle

Two indices of motor unit recruitment, the ramp-force and repetitive-discharge thresholds, were compared in the first dorsal interosseus muscle of ten young and twelve elderly subjects. The purpose was to determine the effect of age on the relationship between the two recruitment thresholds and the spike-triggered average force of motor units. Each subject performed three tasks requiring isometric abduction of the left index finger: a maximum voluntary contraction (MVC), a ramp-and-hold contraction, and a repetitive-discharge task. The elderly subjects used coactivation of the antagonist muscle (second palmar interosseus) more frequently than the young subjects during the ramp-and-hold contraction. Many elderly subjects expressed difficulty with the controlled ramp-down phase of the ramp-and-hold contraction and preferred a coactivation strategy to a derecruitment strategy for this task. There were no differences due to age or gender in the ramp-force thresholds between the various groups. However, the normalized repetitive-discharge threshold was significantly less for the younger subjects and for the male subjects. Nonetheless, the two recruitment thresholds were able to predict the spike-triggered average force with similar success for both the young and the elderly subjects. These data suggest that the recruitment threshold of a motor unit in first dorsal interosseus was characterized equally well by either the ramp-force or repetitive-discharge measurement for both young and elderly subjects but that coactivation was used more frequently by the elderly subjects during the ramp-and-hold task.     

Now you see it, now you don't: Evidence for age-dependent and age-independent cross-modal distraction.

Age-related deficits in selective attention have often been demonstrated in the visual modality and, to a lesser extent, in the auditory modality. In contrast, a mounting body of evidence has suggested that cross-modal selective attention is intact in aging, especially in visual tasks that require ignoring the auditory modality. Our goal in this study was to investigate age-related differences in the ability to ignore cross-modal auditory and visual distraction and to assess the role of cognitive control demands thereby. In a set of two experiments, 30 young (mean age = 23.3 years) and 30 older adults (mean age = 67.7 years) performed a visual and an auditory n-back task (0 ≤ n ≤ 2), with and without cross-modal distraction. The results show an asymmetry in cross-modal distraction as a function of sensory modality and age: Whereas auditory distraction did not disrupt performance on the visual task in either age group, visual distraction disrupted performance on the auditory task in both age groups. Most important, however, visual distraction was disproportionately larger in older adults. These results suggest that age-related distraction is modality dependent, such that suppression of cross-modal auditory distraction is preserved and suppression of cross-modal visual distraction is impaired in aging. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Stepping over obstacles: dividing attention impairs performance of old more than young adults

BACKGROUND: Tripping over an obstacle is a common cause of falls in the elderly. An earlier study of abilities to avoid stepping on suddenly appearing obstacles found that, although healthy old adults had a lower rate-of-success than young adults, the magnitude of that difference was not large. The present study inquired whether dividing attention during such a task would differentially affect young and old healthy adults. METHODS: Rates-of-success were observed in 16 young and 16 old healthy adults (mean ages 24 and 72 years) in avoiding stepping on a band of light that was suddenly projected across their gait path while they walked at their comfortable gait speed. This virtual obstacle was placed at predicted next-footfall locations to give 350 or 450 msec available response times before footfall. During most of the trials the subjects were asked, in addition to trying not to step on the obstacle, simultaneously to respond vocally as quickly as possible when red lights near the end of the walkway turned on. These attention-dividing reaction time tests were of two types: synchronized, when only red lights lit at intervals synchronized with the appearance of the obstacle, and unsynchronized, when green or yellow lights lit in addition to the red lights, with lighting intervals not synchronized with the appearance of the obstacle. RESULTS: When synchronized and unsynchronized reaction time tests were conducted concurrently with the obstacle avoidance tasks, mean rates-of-success in avoidance decreased significantly in both young and old adults. With available response times of 350 msec, mean success rates decreased from their no-division values in the young adults by 14.7% for synchronized reaction and by 19.9% for unsynchronized reaction, attention-dividing tests. Corresponding mean decreases for the old adults were 32.0 and 35.7%. This age difference in the effects of dividing attention was significant. CONCLUSION: Both young and old adults had a significantly increased risk of obstacle contact while negotiating obstacles when their attention was divided, but dividing attention degraded obstacle avoidance abilities of the old significantly more than it did in the young. Diminished abilities to respond to physical hazards present in the environment when attention is directed elsewhere may partially account for high rates of falls among the elderly.     

Highly active antiretroviral treatment in HIV infection: benefits for neuropsychological function

OBJECTIVES: To determine whether highly active antiretroviral therapy (HAART) is associated with reduced HIV-associated neuropsychological impairment. DESIGN: Cross-sectional analysis in a natural history study of adaptation to HIV/AIDS. METHOD: A sample of 130 homo-/bisexual men with HIV/AIDS (mean age, 41 years; 42% non-white) were evaluated with a neuropsychological battery assessing attention, concentration, psychomotor speed, learning, memory and executive function. Subjects taking HAART were compared with those not taking HAART on demographics, CD4 cell count, viral load, scores on individual neuropsychological tests and proportion with neuropsychological impairment. RESULTS: Sixty-nine (53%) subjects were taking HAART, and 48 (37%) were neuropsychologically impaired. Subjects taking HAART had lower mean CD4 cell counts than those not taking HAART (254 versus 342 x 10(6)/l; P < 0.05), although they were more likely to have undetectable viral load (42 versus 20%; P < 0.01) and were less likely to be neuropsychologically impaired (22 versus 54%; P < 0.0001). Subjects taking HAART performed significantly better on tests of attention, concentration, learning, memory, and psychomotor speed. After excluding subjects with potential non-HIV confounders of neuropsychological function, those without neuropsychological impairment had significantly lower mean viral load levels and were more likely to have undetectable viral load than those with impairment. CONCLUSION: These preliminary findings suggest that HAART benefits neuropsychological function through the reduction of viral load.     

Sleep and quantitative EEG in patients with progressive supranuclear palsy

Sleep architecture and quantitative EEG from wakefulness and REM sleep were studied in six patients (mean age, 70.5 years) with progressive supranuclear palsy (PSP) and compared with that of six control subjects (mean age, 69.8 years). Particular attention was given to quantifying REM sleep variables because of the known PSP-associated degeneration of the pedunculopontine tegmentum (PPT)--a critical structure in REM sleep generation. Patients with PSP had a shorter total sleep time, a lower sleep efficiency, a drastic reduction in sleep spindles, an atonic slow-wave sleep, and a lower percentage of REM sleep. The lower percentage of REM sleep was the result of both a reduction in the number of REM periods and a reduction in mean period of duration. REM density was also reduced while REM efficiency, atonia, and phasic EMG were similar to control values. REM sleep findings are consistent with the known role of the PPT in REM sleep induction. A slowing of the awake EEG was found for the six frontal leads and for C4, P4, and T4 in PSP patients. The frontal EEG slowing found in wakefulness is in accord with imaging and neuropsychological studies showing impairment of the frontal lobes in these patients. REM sleep EEG was not significantly slower in any regions. Because all previous studies on PSP have relied on visual inspection of the EEG tracings, the present finding of EEG slowing in the frontal lobes (rather than in the temporal regions or diffusely) suggests that our quantitative EEG approach may be more useful in determining specific regions of impaired cortical activity.     

Spatiotemporal study of event-related desynchronization during self-paced movement

The desynchronization of Alpha band components during a self-paced movement of the thumb was studied in 7 subjects. The EEG was recorded from 23 electrodes located on the frontocentral, central, and parietocentral regions, referred to the right masto?de, 4 s before and 2 s after movement onset. The data were then transformed to obtain 11 source derivations. The temporal evolution of the power of the signal within the Alpha band, every 250 ms, associated to the non parametric statistic test of Wilcoxon, authentifies the event-related desynchronization (ERD). The spatiotemporal analysis of ERD underlines on the central regions, two principal locations of ERD: one controlateral to the movement, starting more than 1 s before the movement; the other, ipsilateral, shorter, during the movement. However, no significance desynchronization was underlined on the vertex. The ANOVA used to analyse these results confirms the principal location of ERD on the central region, and seems to indicate a right lateralisation during the right or the left movement.     

The effect of physical exercise on the response to exertion in the elderly

BACKGROUND: A decrease in adaptation to exertion has been observed as age progresses. Although this decline may also be affected by factors such as health conditions and age, physical inactivity related to sedentary behaviour plays a dominant role. METHODS: In order to evaluate the influence of physical activity on cardiovascular response to exertion in the elderly, 4 groups of 22 subjects each were submitted to maximal electrocardiographic exercise test on a cycloergometer (multistage program with 30 Watts x 3 min. steps). All subjects were male. The composition of the groups was as follows: 1) veteran long distance runners (mean age: 71 +/- 5.4); 2) sedentary veterans (mean age: 69.8 +/- 3.9); 3) young long distance runners (mean age: 25.4 +/- 4.3); 4) sedentary young adults (mean age: 25.8 +/- 3.9). The endurance athletes, well fitted to competition, had been practicing sport activity for at least 3 years. RESULTS: Heart rate, arterial systolic and diastolic blood pressure were recorded; mean blood pressure and double product were calculated at baseline and at the climax of the stress test; furthermore, total and maximal watts were recorded. For each of the parameters, Student's t test for non-paired observations were used to evaluate statistical differences amongst the four groups. The most interesting result arises in the comparison between veteran long distance runners and sedentary young adults: between the two groups no statistically significant differences in workload, expressed as total watts (1649.55 +/- 296.32 vs 1650.00 +/- 446.32; p = NS) and maximal watts (175.91 +/- 19.19 vs 173.18 +/- 24.38; p = N.S.), were observed. On the contrary, highly significant differences in both total (p < 0.01) and maximal (p < 0.01) watts were noticed by comparing long distance runners and sedentary subjects of the same age. CONCLUSIONS: These data support the hypothesis that the progressive reduction in physical activity, which is usually observed in aging, is the major determinant of exercise deconditioning in the elderly.     

Abnormality of myocardial oxidative metabolism in noninsulin-dependent diabetes mellitus

The purpose of this study was to evaluate oxidative metabolism and its response by dobutamine in patients with noninsulin-dependent diabetes mellitus (NIDDM) using 11C-acetate PET. METHODS: We studied 16 patients with NIDDM (9 men, 7 women; mean age 53.7 +/- 12.8 yr) and 6 healthy male control subjects (mean age 41.8 +/- 17.2 yr). None of them had an abnormality on stress-perfusion SPECT. The 11C-acetate clearances (Kmono) were compared regionally for five myocardial segments in all subjects at rest and during low-dose dobutamine stress in 13 patients (8 patients with NIDDM, age 51.9 +/- 13.6 yr; 5 healthy male control subjects, age 45.6 +/- 16.3 yr). Correlation between regional Kmono and rate-pressure product (RPP) was also studied. RESULTS: At rest, the clearance of 11C-acetate was slightly heterogeneous for both patients with NIDDM and healthy control subjects, with smaller values in the apex and inferior wall in both groups. The difference became significant during dobutamine stress in the patients. The RPP-to-Kmono (average for five segments) ratio at rest was slightly smaller in the patients (1042.7 +/- 559.1 x 0.01) than in the healthy control subjects (1391.4 +/- 209.6 x 0.01, not significant), and those during dobutamine stress were almost the same in the two groups (1457.3 +/- 737.4 x 0.01 and 1486.0 +/- 211.8 x 0.01, respectively). A significant correlation was seen between regional Kmono and RPP in every segment in the healthy control subjects (average; r = 0.89; p < 0.01), whereas more scattered correlation with greater regional variation was observed in the patients (average; r = 0.31; p value was not significant). CONCLUSION: Patients with NIDDM showed slight regional heterogeneity in myocardial oxidative metabolism. They also had more scattered correlation between myocardial oxidative metabolism and cardiac work (RPP) than healthy control subjects, with the smallest correlation coefficient observed in the inferior wall. These findings may help the understanding of dynamics in myocardial oxidative metabolism of NIDDM hearts.