Cognitive plasticity, learning potential, and rehabilitation potential are new constructs, which are understood as expressions of neural plasticity. They are assessed through dynamic assessment (or testing-the-limits), using experimental test-training-posttest, a form of evaluation closely related to functional or stress testing in medicine. This research strategy has been used for increasing knowledge about several target populations with intellectual handicaps (socially mentally retarded, brain-impaired, schizophrenia patients, etc.), including older people whose fluid intellectual capacity has declined. Recently, cognitive plasticity has been applied to the study of dementia ( Baltes & Baltes, 1997 ), but there are very few other studies in this area. The basic objective of this research program is to test the extent to which learning potential can be a predictor of the course of dementia. The first specific objective of the research is to test whether learning can discriminate healthy people from those diagnosed with Mild Cognitive Impairment (MCI) and with Alzheimer's Disease (AD). In order to assess cognitive plasticity, a Battery of Learning Potential for Assessing Dementia (BEPAD) was developed, incorporating four tests for assessing visuo-spatial and verbal memory, executive function, and verbal fluency. Two hundred subjects participated in the study: 100 healthy elderly, 50 diagnosed with MCI and 50 with AD. All learning strategies included in the four tests making up the BEPAD appear to be effective: All three groups improved their performance in visual memory, verbal learning, and executive function.

Cachexia is the dramatic weight loss and muscle atrophy seen in chronic disease states, including autoimmunity, cancer, and infection, and is often associated with lymphopenia. We have previously shown that CD4+ T cells that express the lowest density of CD44 (CD4+CD44v.low) are significantly reduced in diabetic NOD mice that are cachexic compared with diabetic mice that are not cachexic. Using this model, and a model of cancer cachexia, we test the hypothesis that CD4+CD44v.low cells play an active role in protecting the host from cachexia. CD4+CD44v.low cells, but not CD4+ cells depleted of CD44v.low cells, delay the onset of wasting when infused into either diabetic or prediabetic NOD recipients. However, no significant effect on the severity of diabetes was detected. In a model of cancer cachexia, they significantly reduce muscle atrophy, and inhibit muscle protein loss and DNA loss, even when given after the onset of cachexia. Protection from wasting and muscle atrophy by CD4+CD44v.low cells is associated with protection from lymphopenia. These data suggest, for the first time, a role for an immune cell subset in protection from cachexia, and further suggest that the mechanism of protection is independent of protection from autoimmunity.

Women with alcoholic cirrhosis showed a higher rate of ascites and encephalopathy but lower liver graft rejection than men with alcoholic cirrhosis. Survival rates were similar between men and women, although slightly lower in women who had hepatitis C virus.

Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) play an important role in HIV infection. Given the viral genetic diversity, the selection of suitable antigens and epitope variants will be important in the design of an effective vaccine. We have previously shown that combinatorial libraries are useful tools to identify epitope mimics as well as potentially cross-reactive natural sequences in protein databases. We have applied this approach to the HIV Gag p17-derived epitope SL9 (SLYNTVATL) to identify broadly recognized SL9 mimics and to assess the cross-recognition of naturally occurring SL9 variants. Nine nonapeptides were identified that were up to one order of magnitude more effective than SL9 in stimulating CTL responses in PBMC from HIVinfected subjects. Using transgenic mice, we demonstrate that a number of these epitope mimics were able to generate de novo T cell responses that cross-reacted with the original SL9 sequence. Particularly, mimics with changes at the relatively conserved Fpocket anchor residue were frequently cross-recognized. This approach may lead to vaccine candidates with higher in vivo immunogenicity and increased potential for cross-recognition of naturally occurring SL9 variants.

Background Tumour growth can promote the loss of muscle mass and function. This is particularly disturbing because overall survival is significantly reduced in people with weaker and smaller skeletal muscle. The risk of cancer is also greater in people who are immune deficient. Muscle wasting in mice with cancer can be inhibited by infusion of CD4 + precursor T cells that restore balanced ratios of naïve, memory, and regulatory T cells. These data are consistent with the hypothesis that stronger anti‐cancer T cell immunity leads to improved muscle mass and function. As a first step to testing this hypothesis, we determined whether levels of circulating T cell subsets correlate with levels of muscle strength in people with cancer. Methods The frequency of circulating CD4 + and CD8 + naïve, memory, and regulatory T cell subsets was quantified in 11 men with gastrointestinal cancer (aged 59.3 ± 10.1 years) and nine men without cancer (aged 60 ± 13 years), using flow cytometry. T cell marker expression was determined using real‐time PCR and western blot analyses in whole blood and peripheral blood mononuclear cells. Handgrip strength, one‐repetition maximum chest press, and knee extension tests were used to determine muscle strength. Performance was determined using a stair climb test. Body composition was determined using dual‐energy X‐ray absorptiometry scan. The Karnofsky and ECOG scales were used to assess functional impairment. Correlations between frequencies of cell subsets with strength, performance, and body composition were determined using regression analyses. Results Our data show significant correlations between (i) higher frequencies of CD8 + naïve ( P = 0.02) and effector memory ( P = 0.003) T cells and lower frequencies of CD8 + central memory T cells ( P = 0.002) with stronger handgrip strength, (ii) lower frequency of regulatory cells with greater lean mass index ( P = 0.04), (iii) lower frequency of CD8 + T cells that express CD95 with greater stair climb power ( P = 0.003), (iv) higher frequency of T cells that co‐express CD197 and CD45RA and greater one‐repetition maximum knee extension strength ( P = 0.008), and (iv) higher expression of CD4 in whole blood with greater functional impairment ( P = 0.004) in people with cancer. Conclusions We have identified significant correlations between levels of T cell populations and muscle strength, performance, and body composition in people with cancer. These data justify a follow‐up study with a larger cohort to test the validity of the findings.