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Query: UMLS:C0751295 (memory loss)
 3,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Involvement of the central nervous system (CNS) is common in patients with advanced disease due to human immunodeficiency virus (HIV). Symptoms range from lethargy and apathy to coma, incoordination and ataxia to hemiparesis, loss of memory to severe dementia, and focal to major motor seizures. Involvement may be closely associated with HIV infection per se, as in the AIDS dementia complex, but is frequently caused by opportunistic pathogens such as Toxoplasma gondii and Cryptococcus neoformans or malignancies such as primary lymphoma of the CNS. The clinical presentations of attendant and direct CNS involvement are remarkably non-specific and overlapping, yet a correct diagnosis is critical to successful intervention. Toxoplasmic encephalitis is one of the most common and most treatable causes of AIDS-associated pathology of the CNS. A great deal has been learned in the last 10 years about its unique presentation in the HIV-infected patient with advanced disease. Drs. Benjamin J. Luft of the State University of New York at Stony Brook and Jack S. Remington of the Stanford University School of Medicine and Palo Alto Medical Foundation's Research Institute have studied T. gondii for many years and are two of the leading experts in the field. This commentary comprises an update of their initial review (J Infect Dis 1988;157:1-6) and a presentation of the current approaches to diagnosing and managing toxoplasmic encephalitis in HIV-infected patients.
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PMID:Toxoplasmic encephalitis in AIDS. 152 Jul 57

Dendritic cells (DC) have a potent antigen-presenting capacity for recruiting resting T cells into immune responses. They also promote expansion of already activated memory T cells. By contrast, macrophages (M phi) are only effective in stimulating memory responses. Infection and depletion of DC occur in human immunodeficiency virus (HIV)-infected individuals and recruitment of T cells into primary responses is blocked. Here comparisons between DC and M phi in stimulating secondary T-cell responses in HIV infection were made. Adherent M phi, and DC isolated by a new method, were separated from peripheral blood of patients in different stages of HIV infection and from uninfected controls and added to allogeneic lymphocytes in mixed leucocyte reactions (MLR). Some were pulsed with influenza virus or tetanus toxoid and used to stimulate autologous T cells. Responses were measured from uptake of [3H]thymidine in 20 microliters hanging drop cultures. DC, but not M phi, from normal individuals stimulated MLR but both populations stimulated secondary responses to recall antigens. DC from all HIV seropositive individuals caused little or no stimulation of any lymphocyte responses. However, M phi from HIV seropositive asymptomatic individuals and those with persistent generalized lymphadenopathy stimulated responses to recall antigens. There was no stimulation using cells from acquired immune deficiency syndrome (AIDS) patients. Blocked DC but not M phi function may underlie progressive immunological non-responsiveness in HIV infection. Without recruitment of resting T cells, loss of memory T cells may be cumulative; failure of secondary activation (e.g. by M phi) would lead to lost T-cell activity. Identification and circumvention of the defect in DC could offer new therapeutic approaches.
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PMID:Antigen-presentation by macrophages but not by dendritic cells in human immunodeficiency virus (HIV) infection. 153 9

Groups of normal old rats and young adult rats were administered a test of conditional discrimination learning in which different visual stimuli were associated with responses to different levers. Initially, rats were tested in a zero-delay condition in which they selected their responses in the presence of the conditional stimuli. They were later tested at 5- and 15-s delays between stimulus presentation and the appearance of the levers. Old rats were impaired in learning the basic conditional discrimination, a test thought to be sensitive to frontal lobe dysfunction. Age differences increased with the length of the interval, revealing a time-dependent memory loss that was attributed to impaired hippocampal function.
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PMID:Conditional learning in aged rats: evidence of hippocampal and prefrontal cortex impairment. 154 74

In a phase II study, 38 previously untreated patients with metastatic colorectal carcinoma were treated with continuous intravenous infusion of 5-fluorouracil (5-FU) 750 mg/m2 daily for 5 days, followed by weekly bolus 5-FU at 750 mg/m2 and subcutaneous interferon (IFN) at 9 million units three times per week. Of 35 evaluable patients, nine (26%) achieved a partial response (95% confidence limit, 11% to 41%), with a median response duration of 7.5 months (range, 4.4 to 17+ months). Seven patients (20%) had a minor response, and 10 (28%) had stable disease. The median length of survival was 13 months (range, 2 to 19+ months). The most common toxicities observed were stomatitis (52%) and diarrhea (43%). Neurotoxicity was seen in 34% of patients and consisted of gait disturbance, dizziness, confusion, memory loss, and dementia. Because of toxicity, 84% of patients required a reduction of the IFN dose by at least 50%, and 63% required reduction of 5-FU by at least 25%. We conclude that while the combination of 5-FU and IFN in patients with advanced colorectal carcinoma has some activity, the regimen is toxic and the observed response rate (26%) is not substantially superior to alternative 5-FU programs.
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PMID:Alfa-2A interferon and 5-fluorouracil for advanced colorectal carcinoma: the Memorial Sloan-Kettering experience. 155 42

The etiology of Alzheimer's disease (AD) is still unknown, and a definitive diagnosis of the disease can be determined only at autopsy or by brain biopsy. AD can be characterized by various structural changes, including cerebral cortical atrophy, neuronal loss, neuritic plaques, and neurofibrillary tangles. The primary defect involves reduced activity of choline acetyltransferase. Neurotransmitters, such as norepinephrine, serotonin, dopamine, and somatostatin, are also compromised. Treatment of AD requires maintenance of a consistent lifestyle and environment for the patient, as well as counseling and support for the patient's family. Medications, which have been effective in some patients, are primarily used to improve cognitive function and modify behavior. Cognitive medications such as tacrine hydrochloride and physostigmine have proven beneficial in some patients, while behavioral medications have been effective in the treatment of depression, aggression, agitation, and anxiety associated with AD. However, the side effect profile of each medication and its probable overall benefit to the individual patient should be evaluated before beginning therapy. Continued research in patients with AD is required to identify medications that will consistently ameliorate the memory loss associated with the disease.
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PMID:Current concepts in the treatment of Alzheimer's disease. 157 22

In this study the recall of autobiographical and public events across the lifespan was examined in a sample of middle-aged and older-aged adults. The tasks were modified versions of one first introduced by Galton (1879), and they required subjects to recall events from specific time periods across their entire lifespan. The four tasks differed in the nature of the episodes requested (autobiographical or public) and whether recall was word-cued or non-word-cued. Verification of public events was assessed archivally, and autobiographical events were verified by a sample of relatives for a subgroup of the subjects and reported events. The results indicated that memory for public events decreases with increased age of the subject, but this effect is not generally found for the recall of autobiographical events. The older-aged subjects were able to recall an equal number of autobiographical episodes from all life segments, whereas recall of news events tended to decrease with remoteness of the episode. These data are contrary to those models that posit general memory loss as a function of age or of remoteness of the events.
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PMID:Remote memory: recalling autobiographical and public events from across the lifespan. 159 52

The germinal center forms a specialized microenvironment that is thought to play a key role in the induction of antibody synthesis, affinity maturation of B cells, isotype switching, and memory B-cell formation. Moreover, the germinal center may also be involved in the maintenance of T-cell memory. In this paper we focus on the role of adhesion receptors in cellular interactions in the germinal center, and discuss evidence indicating that these molecules play an important role in regulating B-cell activation and differentiation. Furthermore, we discuss two important diseases involving the germinal center, i.e., HIV infection and malignant lymphoma. In HIV infection, destruction of the FDC network may explain the selective loss of memory cells observed in otherwise asymptomatic patients and is likely to represent a major pathway leading to AIDS. In follicular lymphoma, escape from physiological apoptosis in the germinal center by overexpression of Bcl-2 appears be a major pathogenetic pathway.
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PMID:Cellular interactions in the germinal center: role of adhesion receptors and significance for the pathogenesis of AIDS and malignant lymphoma. 159 19

Ambient levels of persistent toxic chemicals, chemicals that persist for decades in the environment, have reached levels high enough to affect the health of children. The organochlorines (PCBs, DDT and the dioxin family) accumulate in human adipose tissue. Pregnant women pass the contamination to their fetuses. The developing nervous system is the most vulnerable. Neurobehavioral deficits, including short-term memory loss, are detected in children born to mothers at the high end of the distribution curve of organochlorines. Humans are not alone in their susceptibility to these subtle effects. Wildlife exposed to the same spectrum of organochlorines as humans suffer a variety of behavioral changes. Rats and Rhesus monkeys fed diets containing the organochlorines under laboratory conditions exhibit behavioral changes that persist into adulthood. For humans, food provides 80 percent of organochlorine contamination. Meat, fish, dairy and commercial fruit are the main sources. A vegetarian diet including unsprayed fruit minimizes contamination. The ultimate solution to this public health problem is elimination of the organochlorines from the environment.
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PMID:A new threat to public health: organochlorines and food. 160 49

This study examined the nature of verbal recognition memory in young and old subjects. Following presentation of a word list, subjects undertook a yes-no recognition test and indicated whether their decision was based on explicit recollection or assessment of familiarity. Explicit recollection declined with age, and familiarity-based recognition increased. Furthermore, the extent to which older subjects relied on familiarity-based recognition correlated with neuropsychological indices of frontal lobe dysfunction. A further experiment indicated that the change from explicit recollection to familiarity-based responding was unrelated to changes in older subjects' confidence about their memory. The data indicate the central role of frontal dysfunction in understanding age-related memory loss.
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PMID:Recollective experience, normal aging, and frontal dysfunction. 161 May 18

The memory deficit in Alzheimer's disease (AD) has been characterized as consisting of multiple components. The purpose of this study was to confirm the utility of a two-process model, and to examine changes in the nature and extent of the neuropsychological deficits after a one-year interval. The results replicate the initial observation that the memory loss in AD can be described as consisting of a focal amnesic syndrome and a dysexecutive syndrome characterized by failure of rapid information processing and search of both episodic and semantic memory. One year after the initial observation, all dysexecutive patients and the majority of the amnesic patients had become non-focal. No patient developed a dysexecutive syndrome, but 18 patients developed amnesic syndromes. These results suggest that, like other aspects of the cognitive deficits of AD, the memory loss is multifactorial. These results have implications for understanding the pathophysiology of AD, and for designing pharmacotherapeutic intervention.
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PMID:Longitudinal analysis of a two-component model of the memory deficit in Alzheimer's disease. 161 11


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