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PubMed2003

CpG-A and CpG-B oligonucleotides differentially enhance human peptide-specific primary and memory CD8+ T-cell responses in vitro.

Two distinct types of CpG oligodeoxynucleotide (ODN) have been identified that differ in their capacity to stimulate antigen-presenting cells: CpG-A induces high amounts of interferon-alpha (IFN-alpha) and IFN-beta in plasmacytoid dendritic cells (PDCs), whereas CpG-B induces PDC maturation and is a potent activator of B cells but stimulates only small amounts of IFN-alpha and IFN-beta. Here we examined the ability of these CpG ODNs to enhance peptide-specific CD8+ T-cell responses in human peripheral blood mononuclear cells (PBMCs). The frequency of influenza matrix-specific "memory" CD8+ T cells was increased by both types of CpG ODN, whereas the frequency of Melan-A specific "naive" CD8+ T cells increased on stimulation with CpG-B but not with CpG-A. The presence of PDCs in PBMCs was required for this CpG ODN-mediated effect. The expanded cells were cytotoxic and produced IFN- on peptide restimulation. Soluble factors induced by CpG-A but not CpG-B increased the granzyme-B content and cytotoxicity of established CD8+ T-cell clones, each of which was IFN-alpha/-beta dependent. In conclusion, CpG-B seems to be superior for priming CD8+ T-cell responses, and CpG-A selectively enhances memory CD8+ T-cell responses and induces cytotoxicity. These results demonstrate distinct functional properties of CpG-A and CpG-B with regard to CD8 T cells.

Antigens, Neoplasm↗
PubMed1998

Prospective association of smoking and alcohol use with cognitive function in an elderly cohort.

Cross-sectional studies of the associations of alcohol and tobacco use with cognitive function do not take into account behavior change after memory loss or differential survival. This prospective study examines the association of cigarette smoking and alcohol consumption at baseline with risk of poor cognitive function 13-18 years later. Between 1973 and 1975, 1469 relatively well-educated, noninstitutionalized men and women from Rancho Bernardo, California, answered standardized questions about smoking and alcohol consumption. Between 1988 and 1991, 511 of these men and women completed five standardized cognitive function tests. At baseline, 20.4% of the men and 23.0% of the women were cigarette smokers. Smoking was associated with increased mortality in men but not in women. In surviving male participants, cognitive function test scores did not significantly differ by baseline smoking status. Among female participants, smoking was associated with categorically defined poorer function on two of five tests. At baseline, 16% of the men and 29% of the women were nondrinkers. Drinking more than two drinks per day was associated with decreased mortality in both sexes. Among women, increasing consumption of alcohol predicted a significant decline in the long-term recall and savings scores of the visual reproduction test. Moderate drinking, approximately two drinks per day, predicted categorically defined poor performance on the Buschke long-term recall task in women. Alcohol consumption was not associated with cognitive function in men. Overall, the observed associations were weak, and no clear pattern was observed. Although there were some gender differences in observed associations and a survivor effect cannot be excluded, data from these healthy, educated, noninstitutionalized people offer no compelling evidence that social drinking or cigarette smoking causes or prevents impaired cognitive function in old age. The large number of comparisons and inconsistent results suggest that the few statistically significant findings may be spurious. Additional long-term prospective studies are needed to determine the generalizability of these findings to individuals in less healthy or less well-educated cohorts.

Adult↗
PubMed1998

Differential regulation of human T cell cytokine patterns and IgE and IgG4 responses by conformational antigen variants.

Bee venom phospholipase A2 (PLA) represents the major allergen and antigen in allergic and non-allergic individuals sensitized to bee sting. We have studied specific activation of peripheral T cells by different structural and conformational variants of PLA and secretion of cytokines regulating IgE and IgG4 antibody (Ab) formation. PLA molecules expressing the correctly folded tertiary structure, which show high affinity to membrane phospholipids and were recognized by Ab from bee sting allergic patients, induced high IL-4, IL-5 and IL-13 production in peripheral blood mononuclear cell cultures. In contrast, non-refolded recombinant PLA (rPLA) and reduced and alkylated native PLA (nPLA) induced more IFN-gamma and IL-2 and higher proliferative responses. Differences in proliferation and cytokine patterns among correctly folded and non-refolded PLA resulted from conformation-dependent involvement of different antigen-presenting cell (APC) types. Antigen (Ag)-presenting B cells recognized PLA only in its natural conformation, stimulated Th2 type cytokines and induced IgE Ab. Non-refolded PLA was recognized, processed and presented exclusively by monocytes and induced a Th1 dominant cytokine profile leading to IgG4 production by B cells. The possibility that production of particular cytokine patterns and Ig isotype was influenced by the enzymatic activity of PLA was excluded by using enzymatically inactive H34Q point-mutated, refolded rPLA. These findings demonstrate the decisive role of specific Ag recognition by different APC, depending on structural features, membrane phospholipid binding property and the existence of conformational B cell epitopes, in the differential regulation of memory IgE and IgG4 Ab. Furthermore, they show that a change from IgE-mediated allergy to normal immunity against a major allergen can be induced by rPLA variants that are not recognized by specific Ab and B cells but still carry the T cell epitopes. These features may enable new applications for safer immunotherapy.

Adult↗
PubMed2001

Glucose treatment reduces memory deficits in young adult rats fed high-fat diets.

Feeding rats high-fat diets for 3 months produces a widespread cognitive deficit that affects performance on a wide range of learning and memory tasks. The present study tested the hypothesis that this effect is related to a fat-induced impairment in glucose metabolism. Following 3 months of dietary intervention (20% by weight fat diets, composed primarily of either beef tallow or soybean oil versus standard laboratory chow), male Long-Evans rats were tested on a variable interval delayed alternation (VIDA) task that measures learning and memory functions that differentially involve specific brain regions. Relative to rats fed chow, rats consuming the high-fat diets were impaired on all aspects of VIDA performance. Following baseline testing, rats were maintained on their respective diets and the effect of glucose administration (100 mg/kg BW; i.p.) was examined. For the next 6 days, animals alternately received injections of saline or glucose 30 min prior to VIDA testing. Glucose treatment improved performance, with the effect being most pronounced at the longer intertrial intervals where task performance is sensitive to hippocampal impairment. Importantly, the beneficial effect of glucose were confined to those animals consuming the high-fat diets and were not observed in rats fed chow. These results demonstrate that glucose administration can overcome those deficits associated with hippocampal function in rats fed high-fat diets and are consistent with the hypothesis that high-fat diets, in part, mediate their effect through the development of insulin resistance and glucose intolerance.

Age Factors↗
PubMed1995

The effects of scopolamine, lorazepam, and glycopyrrolate on classical conditioning of the human eyeblink response.

Human eyeblink conditioning, a relatively simple form of learning and memory, has previously been shown to be impaired by the central and peripheral anticholinergic scopolamine. The present study compared the behavioral effects of scopolamine with the benzodiazepine lorazepam and a peripherally active anticholinergic, glycopyrrolate. Thirty-six healthy normal volunteers (mean age: 23.7 years) were studied with 12 assigned double-blind to each of three drug conditions (0.5 mg scopolamine IV, 2 mg lorazepam PO, or 0.2 mg glycopyrrolate IV). Subjects underwent classical conditioning of the eyeblink response in which the conditioned stimulus was an 80 dB binaural tone, and the unconditioned stimulus was a 2 psi airpuff to the right eye. Ten trials of unpaired stimulus presentations were followed by 60 paired trials and finally by an extinction period of five tone-alone presentations. An eyeblink response that occurred during the tone but before the airpuff was scored as a conditioned response (CR). Subjects treated with lorazepam (43% mean CRs) and scopolamine (51% mean CRs) exhibited a significantly lower asymptotic level of conditioning than those treated with glycopyrrolate (85% mean CRs; P < 0.01). However, during extinction, lorazepam-treated subjects (35% CRs) showed a lower overall level of responding to the tone than either scopolamine (60% CRs) or glycopyrrolate (62% CRs) treated subjects (P < 0.05). It seems unlikely that these differences could be accounted for by drug-induced alterations in motor responses because there were no significant differences between the three drug conditions in the frequency, latency, or amplitude of unconditioned responses to the airpuff. Overall, our data indicate that scopolamine and lorazepam impair eyeblink conditioning and suggest that some of the effects of benzodiazepines and anticholinergics on learning and memory can be differentiated using this paradigm.

Adult↗
PubMed2000

Effects of a low dose of alcohol on recollective experience of illusory memory.

RATIONALE: Memory illusions are currently a focus of memory research. Studies using the Deese/Roediger and McDermott paradigm have shown a differential pattern of illusory memories is associated with amnesia and ageing. The effects of pharmacological agents in this paradigm are not yet known. OBJECTIVE: Using this paradigm, the present study investigated the effects of a low dose of alcohol upon recollective experience of illusory memories. METHODS: A double-blind cross-over design was used to compare the effects of alcohol (0.26-0.28 g.kg-1) with a matched placebo drink. RESULTS: High levels of false recognition were obtained across both treatments, replicating previous results. Although the small dose of alcohol employed did not produce gross changes in measures of false memory, it did modify the pattern of recollective experience in terms of remember and know responses. Specifically, it increased the level of remember responses for falsely recognised items (critical lures). CONCLUSION: These results are discussed in terms of ethanol's effects on false recognition of information which was not presented during the study episode. The effects of low dose alcohol on illusory memory are similar to the pattern found in ageing rather than that found in organic amnesia.

Adult↗
PubMed2001

PET measurement of cerebral acetylcholine esterase activity without blood sampling.

Measurement of cerebral acetylcholine esterase (AChE) activity is of clinical interest for the differential diagnosis of memory disorders and dementia. We developed and tested a non-invasive method for quantitation of regional cortical AChE activity with carbon-11-labelled N-methyl-4-piperidyl acetate (11C-MP4A) that does not require arterial blood sampling. AChE activity was measured in terms of the rate constant for hydrolysis of 11C-MP4A (k3). The physiological model is based on the very high AChE activity in the basal ganglia, which are used as a reference structure. Non-invasive k3 was compared with k3 determined with a standard technique by fitting kinetic tissue and metabolite-corrected plasma data in nine subjects with and without dementia. Across all regional values, a very high correlation of 0.92 was found, with a tendency towards moderate underestimation of k3 by 5%-14% with the non-invasive technique as compared to the invasive technique. In addition to its advantages with respect to practicability, the new non-invasive technique overcomes problems of the invasive technique that are related to interindividual variation of delay times between cerebral and peripheral tracer arrival and measurement of very small amounts of non-hydrolysed tracer in plasma samples.

Acetates↗
PubMed2006

Lymphocyte activation in response to melanoma: interaction of NK-associated receptors and their ligands.

In recent years, studies on the molecular and cellular mechanisms of immune responses against melanoma have contributed to a better understanding of how these tumours can be recognised by cytotoxic cells and the mechanisms they have developed to escape from innate and adaptive immunity. Lysis of melanoma cells by natural killer (NK) cells and cytolytic T cells is the result of a fine balance between signals transmitted by activating and inhibitory receptors. In addition to the T cell receptor, these were initially described as NK cell-associated receptors (NKRs) and were later also found on subsets of T lymphocytes, particularly effector-memory and terminally differentiated CD8 T cells. An increase of NKR(+)CD8(+) T cells has been found in melanoma patients, correlating with the expansion of differentiated effector CD8(+)CD28(null) CD27(null) T cells. NKRs can regulate the lysis of target cells expressing appropriate ligands. Activating receptors recognise ligands on tumours whereas inhibitory receptors are specific for MHC class I antigens and sense missing self. Altered expression of MHC class I antigens is frequently found on melanoma cells, preventing recognition by specific cytolytic T cells but favouring NK cell recognition. Changes in the expression of NKR-ligands in melanoma contribute in explaining the differences in the capacity of cytotoxic immune cells to control melanoma growth and dissemination.

Humans↗
PubMedDate not supplied

Arginine vasopressin facilitates reversal learning in albino, but not hooded rats.

Male Holtzman albino and Long-Evans hooded rats were administered one microgram of arginine vasopressin (AVP) or a placebo each day after the acquisition trials of a visual white-black discrimination. Animals were then trained in the reversal of the discrimination. Performance was assessed by the number of trials to criterion during acquisition and reversal. Treatment with AVP resulted in significantly fewer trials to criterion during reversal learning in Holtzman albino rats, but did not influence reversal learning in Long-Evans hooded rats. These results provide evidence that AVP may have differential actions on memory processes in different strains of rats.

Animals↗
PubMed2005

Endosialin (TEM1, CD248) is a marker of stromal fibroblasts and is not selectively expressed on tumour endothelium.

Fibroblasts are a diverse cell type and display clear topographic differentiation and positional memory. In a screen for fibroblast specific markers we have characterized four monoclonal antibodies to endosialin (TEM1/CD248). Previous studies have reported that endosialin is a tumour endothelium marker and is localized intracellularly. We demonstrate conclusively that endosialin is a cell surface glycoprotein and is predominantly expressed by fibroblasts and a subset of pericytes associated with tumour vessels but not by tumour endothelium. These novel antibodies will facilitate the isolation and classification of fibroblast and pericyte lineages as well as the further functional analysis of endosialin.

Animals↗
PubMed1981

Suppression of B-memory cell function by polyclonal lymphocyte activators.

When various polyclonal lymphocyte activators (PLA), such as the capsular polysaccharide of Klebsiella pneumoniae (CPS-K), E. coli lipopolysaccharide (LPS), concanavalin A (Con A), dextran sulfate (DS), phytohemagglutinin (PHA), and pokeweed mitogen (PWM) were injected into mice primed with sheep red blood cells (SRBC), anti-SRBC secondary plaque-forming cell (PFC) responses in vitro of their spleen cells to SRBC and to polyclonal B cell activatory (PBA) were more or less decreased. The decrease in the responsiveness was accompanied by the decrease in the number of SRBC-specific rosette-forming cells (RFC) of B-cell type (B memory cells). This resulted neither from emigration of RFC out of the spleen, nor from change of RFC to antibody-forming cells. Further, we revealed that the decreased responsiveness occurs exclusively in the B cell-rich fraction of the spleen cells from PLA-treated SRBC-primed mice, but not in their T cell-rich fraction. It is concluded therefore that PLA exhibited a common action to reduce selectively B-memory cell function by decreasing the number of B memory cells without differentiation to their end cells, although the strength of the action of various PLA varied.

Animals↗
PubMed2003

Optical analysis of surface changes on early retrievals of highly cross-linked and conventional polyethylene tibial inserts.

Retrieved tibial liners of highly cross-linked and conventional polyethylene were examined for articular and backside surface damage. Surfaces were graded for pitting, machine-mark loss, scratching, abrasion, delamination, and embedded debris. Whereas no difference existed in the damage score for the 2 groups, the highly crosslinked group showed significantly less elimination of machine marks. Wear, surface plastic deformation, or a combination, could account for the damage on these components. Only 1 of the highly crosslinked polyethylene inserts was available for destructive testing. That insert was melted to activate the shape memory, and thus differentiate, between wear versus plastic deformation. Nearly all changes on the articular and backside surfaces disappeared upon melting, and original machining marks reappeared, suggesting that the surface changes for that component were primarily the result of plastic deformation and not material removal.

Arthroplasty, Replacement, Knee↗
PubMed1999

Clinical utility of CERAD neuropsychological battery in elderly Jamaicans.

Information on the clinical utility of neuropsychological tests in non-North-American samples is limited. We examined the diagnostic efficacy of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery in Jamaican men and women age 65 and older. A total of 72 elders were diagnosed as normal and 12 were demented based on history, physical, and neurological examination. Independent of this medical examination, participants were tested with the CERAD battery. Normal controls scored significantly better than dementia patients on all tests in the CERAD battery. A discriminant function found that a combination of Word List Learning Sum Recall and Boston Naming Test correctly classified a total of 81% of the cases (83% of the dements and 81% of the normal controls). This study is the first to demonstrate the clinical utility of the CERAD neuropsychological battery in the differential diagnosis of memory disorders of the aged in a non-North-American sample.

Aged↗
PubMed1991

Lexical but not semantic priming in Alzheimer's disease.

The hypothesis that patients with Alzheimer's disease (AD) have a disturbance in semantic processing was tested using a new lexical-priming task, threshold oral reading. Healthy elderly controls showed significant effects of priming for word pairs that are associatively related (words that reliably co-occur in word association tests) and for word pairs that are semantically related (high-frequency exemplars that belong to the same superordinate category but are not high-frequency associates). AD patients showed effects of priming for associatively related words but not for word pairs that are related only by shared semantic features. These results are consistent with the hypothesis that semantic processing is impaired in AD and suggest that independent networks of relationships among words and among concepts in semantic memory may be differentially disrupted with various forms of brain damage.

Aged↗
PubMed2004

Loss of CCAAT/enhancer binding protein delta promotes chromosomal instability.

The transcription factor CCAAT/enhancer binding protein delta (Cebpd, also known as C/EBPdelta, CRP3, CELF, NF-IL6beta) is implicated in diverse cellular functions such as the acute phase response, adipocyte differentiation, learning and memory, and mammary epithelial cell growth control. Here, we report that lack of Cebpd causes genomic instability and centrosome amplifications in primary embryonic fibroblasts derived from 129S1 mice. Upon spontaneous immortalization, Cebpd-deficient fibroblasts acquire transformed features such as impaired contact inhibition and reduced serum dependence. These data identify a novel role for Cebpd in the maintenance of chromosomal stability and suggest a potential tumor suppressor function in vivo.

Animals↗
PubMed2003

Zinc supplementation has no effect on circulating levels of peripheral blood leucocytes and lymphocyte subsets in healthy adult men.

As a result of evidence documenting harmful effects of Zn supplementation on immune function and Cu status, thirty-eight men were recruited onto a Zn supplementation trial. The aim was to examine the effects of chronic Zn supplementation on circulating levels of peripheral blood leucocytes and lymphocyte subsets. Subjects (n 19) took 30 mg Zn/d for 14 weeks followed by 3 mg Cu/d for 8 weeks to counteract adverse effects, if any, of Zn supplementation on immune status resulting from lowered Cu status. A control group (n 19) took placebo supplements for the duration of the trial. Dietary intakes of Zn approximated 10 mg/d. Blood samples, taken throughout the trial, were assessed for full blood profiles and flow cytometric analyses of lymphocyte subsets. Putative indices of Cu status were also examined. Results indicate that there was no effect of Zn supplementation on circulating levels of peripheral blood leucocytes or on lymphocyte subsets. Cu status was also unaltered. Independent of supplement, there appeared to be seasonal variations in selected lymphocyte subsets in both placebo and supplemented groups. Alterations in circulating levels of B cells (cluster of differentiation (CD) 19), memory T cells (CD45RO) and expression of the intracellular adhesion molecule-1 (CD54) on T cells were observed. Findings indicated no adverse effects of Zn supplementation on immune status or Cu status and support the US upper level of Zn tolerance of 40 mg/d. The seasonal variations observed in lymphocyte subsets in the group as a whole could have implications for seasonal variability in the incidence of infectious diseases.

Adult↗
PubMed1998

Crucial role of tumor necrosis factor receptor 1 expression on nonhematopoietic cells for B cell localization within the splenic white pulp.

During immune responses the initial activation of B cells takes place in T cell zones of periarteriolar lymphoid sheaths (PALS) of the splenic white pulp. After initial activation, B cells migrate into the primary follicles and, in association with follicular dendritic cells (FDCs), undergo clonal expansion and differentiation giving rise to germinal centers (GCs). Peanut agglutinin binding (PNA+) cells of the GC differentiate further into memory or plasma cells. Here we report that in tumor necrosis factor receptor 1-deficient mice (TNFR1(-/-)), the location of B cells was altered and that plasma cells were abnormally distributed in the splenic PALS. In contrast to lymphotoxin alpha-deficient mice (LTalpha-/-), bone marrow or fetal liver transplantation did not correct the abnormal organization of the spleen, location of B cells, the lack of an FDC network, nor the antibody response in TNFR1(-/-) mice. These results argue for a crucial role of TNFR1 expression on nonhematopoietic cells for the maintenance of the splenic architecture and proper B cell location. In addition, the lack in development of an FDC network after adoptive transfer suggests that either FDCs are not of bone marrow origin or that they depend on signals from nonhematopoietic cells for maturation.

Animals↗