The neurobiology of memory changes in normal aging

Cognitive alterations occur over the lifespan of every species studied and have been quantified carefully in humans, other primates and rodents. Correspondingly, changes in hippocampal function have been associated with a number of observed memory impairments across species. It appears that humans, alone, show Alzheimer's disease-like cognitive and neural pathology spontaneously. Thus, a comparison of normal age-related changes in cognition in other animals can help disambiguate the boundary between normal and pathological states of aging in humans. Another important contribution made from studying aging in non-human species is the ability to examine, in more detail, the basic neural mechanisms that may be responsible for brain aging in these species. So far, most of the functional neurobiological studies have been conducted in the aged rat. We propose that the link between rodent and human work can be made much stronger by combining neurophysiological and behavioral investigation of normal aging in the non-human primate.     

The aging mover: a preliminary report on constraints to action.

Locomotion by older adults is typically characterized by performance declines. Older individuals walk more slowly, take shorter steps, and spend a longer time in support than young individuals. Investigators assumed implicitly that declines are related to an inevitable aging process. The purpose of this investigation was to examine constraints that might result in the declines described, outside or in addition to, the general process of aging. We examined two types of terrain over which locomotion might occur, level ground and stairs, and two movement speeds, preferred and fast. Healthy, active females between twenty to eighty years were videotaped. Individuals over sixty years walked at significantly slower speeds, particularly climbing stairs. They used a smaller range of speeds than younger individuals. Despite this slowing, the pattern of coordination between limbs remained essentially the same across the ages tested. The small magnitude of declines observed was attributed to the good health and active lifestyles of these individuals.     

Alpha thalassaemia in an Italian population

The incidence of alpha-thalassaemia in an Italian population has been determined by a survey of random cord bloods for the presence of Hb Bart's. 144 out of 4730 (3%) had detectable amounts of Hb Bart's. Furthermore, alpha-globin gene analysis of 100 random cord bloods showed that five out of 100 had the common type of alpha-thalassaemia caused by a single alpha-globin gene deletion (-alpha). The molecular basis of alpha-thalassaemia was also determined in a selected group of 34 newborns with detectable levels of Hb Bart's. 25 of these cases had the -alpha 3.7 deletion type of alpha-thalassaemia and nine had nondeletion types of alpha-thalassaemia in four of which the molecular defect was detectable directly by restriction enzyme analysis.     

The effects of normal aging on source memory for odors

Source and item memory for olfactory stimuli were assessed in healthy older (65+) and young adults. During the study phase, a male and a female source presented 16 odors to each participant one at a time. Each source presented 8 odors to the participant. As a way to assess source memory, the participant was asked to indicate whether an odor from the study phase was presented by the male or female. As a way to assess item memory, a study phase odor and a novel odor were presented and the participant was asked to indicate which was presented previously. Source memory for odors was impaired in older adults compared with young adults. However, there were no significant differences in odor item memory between young and older adults. Thus, source memory for olfactory stimuli may be a task that is particularly sensitive to age-related changes in the brain.     

Cycloergometric exercise test in normal children: comparison of an Italian and a North American population

The need for a more complete protocol for bicycle ergometer exercise testing in children in our country, induced the Authors to apply the F.W. James protocol to healthy Italian children and then compare the results with a study on a similar american sample population. A total of 102 children, 67 males and 35 females, age range 4.4 - 17 years (mean 10.3 yrs), were examined following the F.W. James protocol. The Authors report the anthropometric and ergometric data obtained, the comparison with James' results and the linear correlation coefficients. Normal reference data were obtained. There were no significant differences between the results obtained from the Italian and American groups, and the correlation coefficients were satisfactory. The results will enable us to benefit from a simple and complete protocol which can be applied to healthy and sick children alike in our country.     

Psychosocial and biochemical interactions in aging: preliminary results from an Italian old sample of "Zincage" project

The study of the interactions among biological factors and psychosocial conditions is a very innovative field, because data are lacking in the scientific literature. Among biological aspects, zinc is an essential element in the elderly, especially in relation to one of the proteins, such as albumin, involved in zinc transport into the cells. In this study, the aim is the assessment of the interrelationship between albumin value (used as an index of the body zinc status) and some psychosocial dimensions in elderly Italian sample recruited for ZINCAGE project, supported by the European Commission in the "Sixth Framework Programme". Some tests and questionnaires were administered to older people included in the trial: the "life-style questionnaire"; the mini mental state examination (MMSE); the geriatric depression scale (GDS-15 items). On the basis of the Senieur Protocol for gerontological studies, a sample of 291 Italian healthy old subjects has been recruited in Central Italy and divided into 3 age groups: (a) 125 subjects aged from 65 to 74 years, (b) 89 subjects aged from 75 to 84 years, (c) 77 subjects aged >or=85 years (classified like successful old people). No cognitive impairment assessed by MMSE was observed in 67.5% of the sample; 64.0% had GDS score less than 5, indicating no depression, whereas the prevalence of biological albumin deficiency (<3.5 g/dl) found in Italian old people was 21.0%. Sixty one percent of subjects with albumin deficiency displayed higher values of GDS (>or=5). These preliminary results showed an interrelationship among serum albumin value and psychosocial aspects in Italian old population, suggesting that low albumin values may be involved in impaired psychological dimensions.     

Differential effects of normal aging on memory for odor-place and object-place associations

Odor-place and object-place associative memory were compared in healthy older (over the age of 65) and young (18 to 25 years of age) adults. Twelve spatial locations were defined on a tabletop board. Either six odors or six objects were presented one at a time and each was paired with a location on the board. The participant then was presented with each stimulus individually and asked to place it in its paired location. Older adults showed impaired odor-place associative memory but unimpaired object-place memory compared to young adults. Item recognition memory for the individual stimuli or locations used on the associative memory task was similar in both groups. The results suggest that odor-place associative memory is particularly affected by age-related brain changes.     

The aging of memory: A method for the assessment of qualitative changes

Age associated memory changes are traditionally described in terms of quantity of recall. Evidence of qualitative changes associated with aging could lead to a modification of this approach. The primacy and recency effects in serial learning provide a good model to evaluate these qualitative modifications. Our study was designed to investigate modifications of the serial effects in serial learning related to age and modality. We have comparatively investigated, with 120 normal subjects of both sexes, the influence of age and a latent semantic structure, consisting on four taxonomic categories, on the occurrence of primacy and recency effects in a list of verbal stimuli. The presence of a latent structure in the list of stimuli interacted with age in a relearning trial causing the recency effect to disappear more evidently in younger subjects. The same structure did not affect the primacy effect which, on the contrary, was influenced by age only. These results suggest a differential role across age of the automatic processing of working memory versus the role of the semantic-lexical processing of the central processing unit within working memory. They also, demonstrate the importance of age in influencing memory resources which change the quality and quantity of working memory proficiency.     

Incidence of hepatitis A virus infection among an Italian military population

Summary In 1990, a prospective serological survey to estimate the rate of clinical and inapparent infection with hepatitis A virus (HAV) was performed in a cohort of 1,268 soldiers, 18–24 years old, during an 8 month period in the Campania region in Italy. At the time of enrollment 318 (25%) of the 1,268 soldiers were positive for total antibodies to HAV (anti-HAV). None of them was positive for IgM anti-HAV. Among the 950 susceptible subjects who were followed up for 8 months, eight (0.8%) later seroconverted to anti-HAV positivity. This figure corresponds to an incidence of 1.3/100 person/years (eight seroconversions during 633.3 years of observation). There were two clinical (with presence of IgM-anti-HAV) and six inapparent infections. The clinical/subclinical HAV ratio was 1 : 3. These findings indicate that the risk of HAV infection among soldiers residing in this area is not negligible.

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Inzidenz der Hepatitis A Virus Infektion bei einer italienischen Militärpopulation

Zusammenfassung Um die Rate der klinischen und subklinischen Infektionen mit dem Hepatitis A Virus (HAV) zu bestimmen, wurde 1990 eine prospektive serologische Überwachungsstudie bei 1268 18–24 Jahre alten Soldaten während einer Zeitspanne von acht Monaten in der Region Campagna, Italien, durchgeführt. Bei Aufnahnme wiesen 318 der 1268 Soldaten (25%) Antikörper gegen HAV (anti-HAV) auf. Keiner war positiv für IgM anti-HAV. Unter den 950 empfänglichen Soldaten, die acht Monate lang beobachtet wurden, traten acht Fälle von Serokonversion zu anti-HAV auf (0,8%). Diese Zahl entspricht einer Inzidenz von 1,3/100 Personen/Jahr, (acht Serokonversionen während 633,3 Beobachtungsjahren). Zwei Infektionen wurden klinisch manifest (mit Nachweis von IgM anti-HAV) und sechs Infektionen verliefen klinisch inapparent. Die Rate klinischer zu subklinischen HAV-Infektionen betrug 1 : 3. Diese Daten zeigen, daß das Risiko für Soldaten, die in dieser Region wohnen, nicht zu vernachlässigen ist.

     

A visual recognition memory test for the assessment of cognitive function in aging and dementia

Young, non-demented elderly, and elderly demented subjects were administered a computerized visual recognition memory task. In the task, subjects were instructed to point out the new object from a group of objects whose number was progressively incremented. The test was subject-paced and made use of face-valid stimulus materials; it is closely comparable to tests developed for memory assessment in non-human primates that are sensitive to the effects of hippocampal ablation. The present task was found to elicit significant differences in performance between young and non-demented aged subjects, between the non-demented and demented elderly, and between demented subjects in the early and more advanced stages of senile dementia of the Alzheimer type (SDAT). In a discriminant analysis, the visual recognition memory test scores correctly classified 72.6% of the aged subjects and early SDAT patients. No significant difference in task performance was found between SDAT patients and demented patients with a significant cerebrovascular etiological component. Thus, although the task does not appear to be suitable for diagnostic purposes it would be useful for the assessment of treatment effects upon age-related cognitive dysfunction.     

Cocaine: an independent risk factor for aortic sudanophilia. A preliminary report.

Several recent autopsy reports indicate an increased prevalence of coronary atherosclerosis in ischemic heart disease temporally associated with cocaine abuse. The objective of this study was to conduct a retrospective analysis of sudanophilic lesions in young asymptomatic individuals who abused cocaine. Twenty-six cases (15-34-year-old black males) were examined from the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study. Sixteen subjects (mean age 25 +/- 1 years) had a positive toxicologic screen for cocaine and/or its major metabolites at autopsy and were confirmed habitual cocaine abusers. The remaining 10 cases (mean age 24 +/- 2 years) were subjects with a negative toxicologic screen at autopsy and no history of illicit drug abuse. Post-mortem blood was collected for lipoprotein analysis and determination of smoking status. The aorta and right coronary arteries were stained with Sudan IV and the degree and extent of sudanophilia was quantitated by image analysis. Multiple linear regression analysis of cocaine, age, smoking status, VLDL+LDL-C/HDL-C ratio and HDL-C as predictor variables of percentage intimal surface involvement, revealed an association between cocaine abuse and the extent of sudanophilia in both the thoracic and abdominal aorta (P = 0.002 and 0.049, respectively). Analysis of risk factors or of cocaine abuse as predictors of sudanophilia did not achieve statistical significance in the right coronary artery. These preliminary results suggest that habitual use of cocaine, through unknown mechanism(s), increases aortic sudanophilia independent of traditional risk factors.     

Primary sulphone resistance. A preliminary report.

A case of lepromatous leprosy proven to be a primary sulphone resistant one, has been reported. Bacilli from the case were found to be resistant as checked by their continued growth in the foot pads of mice receiving diet containing 0.001% D.D.S. A study to identify such cases is being systematically persued.     

Raynaud's phenomenon: prevalence in an Italian population sample

To estimate the prevalence of Raynaud's phenomenon (RP) in an Italian population aged 18 years and above, a validated questionnaire was mailed to a random sample of 3,664 subjects. Sociodemographic data and data regarding the prevalence of RP symptoms were collected. Trained rheumatologists carried out a subsequent standardized clinical examination to confirm diagnosis of RP and to detect associated diseases. The subjects (2,155) completed the questionnaire, with 45 reporting RP [prevalence rate 2.1%, 95% confidence intervals (CI) 1.8–2.4]. The mean age [standard deviation (SD)] was 57.5 (12.7), and 40 (88.8%) were women. Prevalence was found higher in women (3.4%, 95% CI 2.8–4.1) than in men (0.5%, 95% CI 0.2–0.9) (p<0.0001). A connective tissue disease was diagnosed in six (0.28%) subjects, three of the participants (0.14%) were identified as having RP associated to an idiopathic carpal tunnel syndrome, and 36 (1.67%) were diagnosed as having primary RP. Our study has found a lower prevalence of RP than others have reported. There is thought to be an association with climate and ethnic factors. No relationship was found regarding factors that are thought to be among the most relevant triggering factors for RP, e.g., occupational exposure. Differences with previous studies may be related to the current characteristics of the population surveyed.