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AIM The present study was performed to examine the clinicopathological significance of hyaline deposits in the smooth muscle of the interlobular artery (interlobular hyaline arteriopathy [IHA]) in renal allografts. METHODS Tissue specimens that included the interlobular artery from biopsies performed from January 2012 to December 2015, as well as specimens from biopsies performed ≥1 year after living kidney transplantation were analyzed. Biopsies of recipients with new-onset diabetes mellitus after transplantation were excluded, as well as those of recipients who had undergone transplantation because of diabetic nephropathy. Arteriolopathy was evaluated using the aah score determined by the Banff 2007 classification. RESULTS In total, 51 specimens with IHA lesions were identified among 381 biopsies obtained from 243 recipients performed ≥1 year after kidney transplantation. Among these 51 biopsies, 18 specimens had a score of aah3, 29 had a score of aah2, and four had a score of aah1. The incidence of IHA lesions was 3.6% at ≥1 to

Fluid volume overload is common and is associated with adverse outcomes in hemodialysis patients. Practicing physicians individually manage fluid volume balance in their dialysis patients according to blood pressure, interdialytic weight gain, cardiac function, nutritional status, and other comorbidities. However, accurate assessment of fluid volume status remains a concern. Indicators of dry weight target have been explored further with newer concepts and technologies. In general, total body water comprises approximately 50%-60% of adult body weight (range, 45%-75%), and water comprises 73.3% of lean body mass. The standard hydration status between intracellular water and extracellular water is maintained at a ratio of 62:38 in healthy adults, which, however, is influenced universally by body cell volume driven by age and muscle mass. Fluid volume imbalance in dialysis patients also is characterized primarily by decreased body cell mass associated with aging and muscle attenuation, as well as excess extracellular water content associated with sodium retention, which may be associated with the reserve capacity for volume overload. Indeed, dialysis patients with a leaner body mass have a higher prevalence of hypertension, poorer hypertension control, and greater left ventricular hypertrophy. Understanding of these body composition changes by aging and sarcopenia can aid clinical decision making in the dry weight assessments in dialysis patients. Advising patients with consistently high interdialytic weight gain to practice salt restriction and providing appropriate nutritional support for malnourished patients with downward trajectory in their dry weight would be of great help to achieve optimal fluid volume status.

Cognitive function as measured by the Hebb-Williams maze task was examined in Fischer 344 male rats that had been exposed to an enriched environment for periods of variable duration and at different starting ages. In one experiment, rats were exposed to environmental enrichment from weaning until the age of 2.5, 15, or 25 months. The results of 12 problems of the Hebb-Williams maze task showed that the enriched rearing condition improved the learning ability in all the age groups; however, factor analysis and ANOVA demonstrated that four of the 12 maze problems were not suitable for detecting the effect of age under different environmental conditions. Reanalysis of the results obtained with the other eight maze problems more clearly revealed both the effects of rearing condition and aging. The latter analysis demonstrated that the learning rate of rats reared under enriched conditions was faster than that of rats reared under standard social conditions. Short-term (3-month) exposure also had positive effects on cognitive function in both adult (11-month-old) and aged (22-month-old) animals. The effect of long-term exposure to an enriched environment starting at weaning was much greater than that of short-term exposure in aged rats, whereas the effects of both long-term and short-term exposure were almost the same in adult rats. These results show that aged animals still have appreciable plasticity in cognitive function, and suggest that environmental stimulation could benefit aging humans as well. © 2002 Wiley-Liss, Inc.

The effects of a carnitine derivative, acetyl-L-carnitine (ALCAR), on the cognitive and cholinergic activities of aging rats were examined. Rats were given ALCAR (100 mg/kg) per os for 3 months and were subjected to the Hebb-Williams tasks and a new maze task, AKON-1, to assess their learning capacity. The learning capacity of the ALCAR-treated group was superior to that of the control. Cholinergic activities were determined with synaptosomes isolated from the cortices. The high-affinity choline uptake by synaptosomes, acetylcholine synthesis in synaptosomes, and acetylcholine release from synaptosomes on membrane depolarization were all enhanced in the ALCAR group. This study indicates that chronic administration of ALCAR increases cholinergic synaptic transmission and consequently enhances learning capacity as a cognitive function in aging rats.

Numerical synaptic density and synaptic vesicle density in rat frontal cortex were examined by electron microscopy as a function of age. The density of axospinous synapses, a major population of synapses, was found to peak at age 1 month, and to gradually decrease with aging. The synaptic vesicle density in axospinous synapses was shown to rapidly increase to a peak during the first 3 weeks and then decrease to the adult level, which remained unchanged in senescence. The time course of synaptic changes in aging is presented in this study. In a previous report (Saito et al. [1994] J. Neurosci. Res. 39:57-62), we showed that enriched rearing conditions restored the age-related decrease of synaptophysin contents. This might be due to increased numerical synaptic density or enhanced packing density of synaptic vesicles in synapses. The results of the present study support the latter explanation; that is, synaptic vesicle contents were increased without changes in synaptic density. Synaptic plasticity induced by environmental stimulation is shown to relate with synaptic strengthening, but not with the formation of new synapses.