フォールスメモリにおける若年者と高齢者の差異―保持間隔からの考察―

The present study aimed to determine relationships between intramyocellular lipid and biochemical profiles or muscle strength in elderly (n=15; mean age, 71years) and young (n=15; mean age, 21years) male and female adults. Levels of intramyocellular lipid in the vastus lateralis and biceps femoris muscles were determined using 1 H-magnetic resonance spectroscopy. Fasting blood samples were collected to measure levels of glucose, insulin, haemoglobin A1c, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, free fatty acid, triglyceride, adiponectin, and high-sensitivity C-reactive protein. Muscle strength was assessed as maximal voluntary contraction during isometric knee extension. Muscle cross-sectional area in the vastus lateralis was measured using magnetic resonance imaging. Specific force (Ncm-2 ) indicating force generation capacity was calculated as muscle strength (N) divided by the muscle cross-sectional area of the vastus lateralis (cm2 ). The intramyocellular lipid content was similar in both muscles in both groups. The intramyocellular lipid content in the biceps femoris significantly correlated with serum free fatty acid levels (r=0·62, P<0·05), and that in the vastus lateralis significantly and inversely correlated with specific force (r=-0·58, P<0·05) in the young, but not in the elderly adults. The relationship between the intramyocellular lipid content in the thigh muscles and biochemical profiles, or specific force differed between elderly and young adults. Age-associated changes in morphology, function and metabolic factors apparently influence intramyocellular lipid metabolism in the thigh muscles.

The production of false recognition and the associated state of consciousness following encoding in a naturalistic context in aging

This study compared the doses of sugammadex needed for rapid recovery from deep neuromuscular blockade (NMB) between young and elderly adults. Twenty-two young (20-40yrs) and 22 elderly (≥70yrs) adults were enrolled, and deep NMB of 1-2 post-tetanic counts was maintained with rocuronium intraoperatively. Predetermined doses of sugammadex were given at the end of surgery starting at 4.0mg/kg for the first patient of each group. Doses were decreased or increased in following patients by 0.5mg/kg, depending on the 'success' or 'failure' of rapid recovery in the preceding patient. 'Success' was defined as adequate recovery (train-of-four ratio 0.9) within 2min. after sugammadex administration. The median (range) of ages was 29 (20-40) and 73 (70-84)yrs for the young and elderly adults, respectively. Doses of sugammadex facilitating adequate recovery from deep NMB within 2min. in each patient population with 50% and 95% probability were defined as ED50 and ED95 , respectively. The ED50 estimated by the Dixon's method was significantly higher in the elderly compared to young adults [4.2±0.4mg/kg versus 3.3±0.3mg/kg, p<0.001]. The ED50 (83% CI) estimated by isotonic regression was 4.5 (4.2-5.0)mg/kg in elderly adults and 3.3 (3.2-3.4)mg/kg in young adults. The ED95 (95% CI) estimated by isotonic regression was 5.4 (4.9-5.5)mg/kg and 4.4 (3.9-4.5)mg/kg in the elderly and young adults, respectively. In conclusion, dose adjustments of sugammadex should be considered when rapid recovery from deep NMB is needed in elderly adults.

BackgroundThe α-Klotho is known to be involved in longevity and various age-related diseases, including cognitive impairment. BACE1, an important enzyme associated with the pathological process of Alzheimer's disease (AD), serves as a biomarker for predicting changes in cognitive function. Although both proteins are closely linked to age-related cognitive function, the mechanism of their interaction remains unclear.ObjectiveTo identify the enzymatic digestion relation between α-Klotho and BACE1 and the specific cleavage site.MethodsThirty elderly and forty-five young individuals were recruited. The cleavage product was identified by Coomassie blue staining, western blot, and MALDI-TOF mass spectrometry. The concentrations of plasma proteins were measured by ELISA.ResultsA new protein product was identified after the digestion reaction. BACE1 cleaved the α-Klotho peptide 951-981 at the F-T residues. When the F-T residues were replaced with K-K, BACE1 was unable to cleave the mutant peptide. The plasma levels of α-Klotho were significantly lower in elderly participants than in young participants (p < 0.0001). However, there was no significant difference in plasma BACE1 levels between elderly and young participants (p = 0.164). In elderly adults, there was a significant positive correlation between plasma BACE1 and α-Klotho protein levels (p = 0.009, r = 0.469), while this correlation was not observed in young adults (p = 0.170, r = -0.208).ConclusionsThe anti-aging protein α-Klotho is a substrate of BACE1 with a specific cleavage site at F-T. The BACE1/α-Klotho pathway may serve as a common axis for age-related cognitive decline.

Age-related changes in neural activity associated with familiarity, recollection and false recognition.

Older adults are more prone to false recognition than younger adults, particularly when new information is semantically related to old information. Curiosity, which guides information-seeking behavior and has beneficial effects on memory across the life span, may offer protection against false recognition, but this hypothesis has not been tested experimentally to date. The current study investigated the effect of curiosity on correct and false recognition in younger and older adults (total N = 102) using a trivia paradigm. On Day 1 of the study, participants encoded trivia questions and answers while rating their curiosity levels. On Day 2, participants completed a surprise old/new recognition test in which they saw the same trivia questions. Half of the questions were paired with old (correct) answers, and half were paired with new (incorrect) answers. New answers were either semantically related or unrelated to correct answers. For both age groups, curiosity at encoding was positively associated with correct recognition. For older adults, semantically related lures produced more false recognition than unrelated lures. However, this effect was mitigated by curiosity, such that older adults were less likely to endorse semantically related lures for high- versus low-curiosity questions. Overall, these results extend prior findings of curiosity-related memory benefits to the domain of recognition memory, and they provide novel evidence that curiosity may protect against false memory formation in older adults.

In a previous study, we succeeded in improving the spatial working memory (WM) performance in healthy young persons by applying transcranial magnetic stimulation (TMS) to the parietal cortex and simultaneously measuring the oxygenated hemoglobin (oxy-Hb) level using near-infrared spectroscopy (NIRS). Since an improvement in WM was observed when TMS was applied to the right parietal cortex, the oxy-Hb distribution seemed to support a model of hemispheric asymmetry (HA). In the present study, we used the same study design to evaluate healthy elderly persons and investigated the effect of TMS on WM performance in the elderly, comparing the results with those previously obtained from young persons. The application of TMS did not affect WM performance (both reaction time and accuracy) of 38 elderly participants (mean age = 72.5 years old). To investigate the reason for this result, we conducted a three-way ANOVA examining oxy-Hb in both young and elderly participants. For the right parietal TMS site in the elderly, TMS significantly decreased the oxy-Hb level during WM performance; this result was the opposite of that observed in young participants. An additional three-way ANOVA was conducted for each of the 52 channels, and a P value distribution map was created. The P value maps for the young participants showed a clearly localized TMS effect for both the WM and control task, whereas the P map for the elderly participants showed less significant channels and localization. Further analysis following the time course revealed that right-side parietal TMS had almost no effect on the frontal cortex in the elderly participants. This result can most likely be explained by age-related differences in HA arising from the over-recruitment of oxy-Hb, differentiation in the parietal cortex, and age-related alterations of the frontal-parietal networks.

Neuropsychological studies on the processing of some specific cognitive functions throughout aging are essential for the understanding of human cognitive development from ages 19 to 89.ObjectivesThis study aimed to verify the occurrence of differences in the processing of episodic memory, concentrated attention and speed of attentional processing among four age groups of adults.MethodsA total of 136 neurologically healthy adults, aged 19-89, with 9 or more years of schooling, took part in the study. Participants were divided according to four age groups: young, middle-aged, elderly and oldest old adults. Subtests of the Brief Neuropsychological Evaluation Instrument (NEUPSILIN) were applied for the cognitive assessment. Mean score of corrected answers and of response times were compared between groups by means of a one-way ANOVA test with post-hoc Scheffe procedures and ANCOVA including the co-variables of years of schooling and socio-economical scores.ResultsIn general, differences in performance were observed from 60 years old on. Only the episodic memory task of delayed recall reflected differences from the age of around 40 onwards and processing speed from around the age of 70 onwards. Thus, differences were found between the age groups regarding their cognitive performance, particularly between young adults and elderly adults, and young adults and oldest old adults.ConclusionsOur research indicates that the middle-aged group should be better analyzed and that comparative cross-sectional studies including only extreme groups such as young and elderly adults are not sufficient.

MP71-16 GENERATION DIFFERENCE ON THE ASSOCIATION BETWEEN LOWER URINARY TRACT SYMPTOMS AND LATE-ONSET HYPOGONADISM SYMPTOMS: ANALYSIS OF 1398 HEALTHY YOUNG AND ELDERLY ADULTS

Streptococcus pneumoniae is a leading cause of morbidity and mortality in both developed and developing countries. The current pneumococcal polysaccharide (PPS) vaccine is highly effective in young adults; however, vaccine efficacy is dramatically decreased in the elderly population. We hypothesized that the decreased vaccine efficacy in the elderly results from altered variable gene family usage. We have characterized the immunoglobulin G gene usage of the antibody response to PPS4 and PPS14 in 20 young and 20 elderly adults. The variable heavy (V(H)) gene repertoire of human peripheral B cells was amplified by using PCR. A total of 364 heavy chain sequences with specificity for PPS4 and 305 heavy chain sequences for PPS14 were analyzed from young adults. In addition, a total of 325 sequences for PPS4 and 291 sequences for PPS14 were obtained from elderly adults. Complete sequence identity, somatic mutation frequencies, and V(H) gene usage was determined in response to PPS4 and PPS14. In all volunteers, the immune response to both polysaccharides consisted predominantly of heavy chains belonging to the V(H)3 gene family. There were significant differences in the variable gene repertoire between young and elderly adults. Somatic mutation occurred more frequently in sequences derived from young compared to elderly derived sequences. With aging, a loss of oligoclonality was noted in response to PPS4 and PPS14 compared to young adults. The observed differences in V(H) repertoire, somatic mutation, and loss of oligoclonality may contribute to decreased vaccine efficacy in the elderly.

Sex-specific differences in the association between body mass index and brain aging in young adults: Findings from the human connectome project

Old cells die hard - sympatholysis and the ageing erythrocyte.

The purpose of the present study was to investigate the effects of practice on a modified version of the Matching Familiar Figures test in young, middle-aged and elderly adults. Forty-eight young, 48 middle-aged and 48 elderly adults were each presented with 48 match-to-standard items. the dependent variables were the number of errors committed and the latency to first response. the performance of both young and middle-aged adults reflected rather stable speed/accuracy trade-off decisions that did not change as a function of practice. the young adults responded more quickly and made more errors than the middle-aged adults across all 48 trials. the performance of elderly adults, on the other hand, did change as a result of practice; their latencies increased and their error rate decreased across trials. Elderly adults started out making more errors than young adults but by the end of the 48 trials, their error rate was lower than that of young adults. In the final trials, the error rate of elderly adults was midway between the rates of young and middle-aged adults. Thus, practice facilitated the performance of elderly adults but had no effect on the performance of young and middle-aged adults.

Dual Task Demands and Gist-Based False Recognition of Pictures in Younger and Older Adults

In the Deese-Roediger-McDermott (DRM) paradigm, participants falsely recall or recognize a nonpresented word (critical lure), highly associated with previously studied words. As numerous DRM studies have found a robust false memory effect at the behavioural level, event-related potentials (ERPs) studies have searched for possible overlapping in brain electrical activity between true and false memory. Using the DRM paradigm, the present experiment manipulated the sensory modality of stimulus presentation (auditory vs. visual) in the study phase to analyse the effect of modality match between study and test on true and false recognition. Words were therefore presented either visually or auditorily at study and always visually at test. True recognition was found to be significantly higher in the modality 'match' condition (visual-visual) than in the 'mismatch' condition (auditory-visual), whereas there was no modality-match effect on false recognition of critical lures. A general, overlapping was found between ERP correlates of true and false recognition: FN400 (300-500 ms), left-parietal (400-800 ms) and late right-frontal (1000-1500 ms) old/new effects were similar for both studied words and critical lures. No sensory modality-match effect was associated with FN400 or left-parietal old/new effects. Only the late right-frontal activity was modulated by modality manipulation, with significantly more positive ERPs in the modality-match condition. Sensory modality match of stimulus presentation, therefore, dissociated true and false recognition memory only at the behavioural level but not at the ERP level. Overall, true and false recognition memories seem to share common underlying processes.