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At least 793 records · Page 44Linked to original sources
PubMed1999

Odor identification, consistency of label use, olfactory threshold and their relationships to odor memory over the human lifespan.

The purpose of this study was to investigate olfactory threshold, odor identification, consistency of label use and their relationships to odor memory in the context of semantic/episodic memory across the human lifespan. A total of 137 subjects aged 4-90 years were tested with several olfactory test procedures. We found that olfactory sensitivity was well developed in children despite the finding that their odor naming and odor memory were inferior to that of adults. In the elderly population, olfactory functions gradually declined, with odor memory and odor identification demonstrating the most significant decline. Semantic encoding was differentially related to odor memory over the human age span. Whereas consistency of label use was the main predictor for odor memory in children and young adults, olfactory identification ability was the main predictor in the elderly study group. We also calculated response bias for the separate age groups and found no differences between children, young adults and elderly. However, with age false alarm rates increased. We conclude that children possess equal olfactory sensitivity compared with adults; however, due to limitations in linguistic capabilities and familiarity to odorants, odor memory and odor identification performance was limited. Additionally, our data indicate major alterations of olfactory processing in advanced age with substantial losses in odor memory and odor identification performance.

Adolescent↗
PubMed2004

Vpx proteins of SIVmac239 and HIV-2ROD interact with the cytoskeletal protein alpha-actinin 1.

vpx genes of human immunodeficiency virus type 2 (HIV-2) and immunodeficiency viruses from macaques (SIVmac), sooty mangabeys (SIVsm) and red-capped mangabeys (SIVrcm) encode a 112 aa protein that is packed into virion particles via interaction with the p6 domain of p55(gag). Vpx localizes to the nucleus when expressed in the absence of other viral proteins. Moreover, Vpx is necessary for efficient nuclear import of the pre-integration complex (PIC) and critical for virus replication in quiescent cells, such as terminally differentiated macrophages and memory T cells. Vpx does not contain sequence elements that are homologous to previously characterized nuclear localization signals (NLSs). Therefore, it is likely that Vpx-dependent import of the PIC is mediated by interaction of Vpx with cellular proteins that do not belong to the classical import pathways. By using a yeast two-hybrid screen, alpha-actinin 1, a cytoskeletal protein, was identified to interact with SIVmac239 Vpx. Interestingly, deletion of the proline-rich C-terminal domain (aa 101-112) of Vpx, which is important for nuclear localization, resulted in loss of interaction with alpha-actinin 1. These findings suggest that the interaction with alpha-actinin 1 may play an important role in the transport of Vpx to the nucleus and in Vpx-mediated nuclear import of the PIC.

Actinin↗
PubMed1998

Gastric low-grade mucosa-associated lymphoid tissue lymphomas: their histogenesis and high-grade transformation.

Gastric low-grade mucosa-associated lymphoid tissue (MALT) lymphoma is a unique disease. A vast majority of lymphoma cells are centrocyte-like cells or resemble monocytoid B cells, and occasionally show plasmacytic differentiation. Immunophenotypical and immunogenotypical examinations have indicated that they are in the differentiation stage of memory B cells, whose normal counterparts are marginal zone lymphocytes or monocytoid B cells in the lymphoid tissues. It arises from chronic gastritis closely associated with Helicobacter pylori (H. pylori) infection. Mucosa-associated lymphoid tissue lymphomas of other organs are also based on acquired MALT associated with chronic inflammation or autoimmune diseases. Interestingly, the majority of gastric low-grade MALT lymphomas regress by the eradication of H. pylori. The lymphoma cells, however, are not derived from B cells reacting with H. pylori itself but from autoreactive B cells. Although the mechanism of their oncogenesis has not been clarified, previous data suggest that autoreactive B cells proliferate in response to H. pylori-specific T cells, presumably with some cytokines. The genetic instability of such B cells then induces chromosomal abnormalities including trisomy 3 and/or other genetic changes. These B cells have the ability of autonomic proliferation and, even so, they might be sensitive to T cell stimuli. Low-grade gastric lymphomas occasionally progress to high-grade malignancy. The high-grade component of MALT lymphomas are composed of large-sized lymphoma cells that are morphologically indistinguishable from nodal large B cell lymphomas. This high-grade transformation is associated with p53 abnormalities or Bcl-6 overexpression. Gastric MALT lymphoma may provide a useful model in understanding multistep lymphomagenesis.

Aged↗
PubMedDate not supplied

Lidocaine interrupts the conditioned natural killer cell response by interfering with the conditioned stimulus.

In the present study, lidocaine, a local anesthetic that inhibits the initiation or conduction of nerve impulses, was used to differentiate between the memory for the conditioned stimulus (CS) and the memory for the CS and unconditioned stimulus (US) association. Lidocaine was used to block memory formation. It was administered into the cisterna magna to localize the inhibition to the central nervous system (CNS) where circuits for the CS and US exist. The results show that lidocaine specifically blocks the ability of the CS to stimulate the circuits responsible for storing the CS/US association, but it does not interfere with the inherent ability of the US to signal the CNS and trigger a peripheral response. The observation that the CS circuit can be interrupted independently of the US circuit suggests that these signals come together to form a new circuit for the memory of the association. The association memory forms later and is independent of the memory for the CS.

Animals↗
PubMed2005

Brain response to injury and neurodegeneration: endogenous neuroprotective signaling.

Synaptic activity and ischemia/injury promote lipid messenger formation through phospholipase-mediated cleavage of specific phospholipids from membrane reservoirs. Lipid messengers modulate signaling cascades, contributing to development, differentiation, function (e.g., memory), protection, regeneration, and repair of neurons and overall regulation of neuronal, glial, and endothelial cell functional integrity. Oxidative stress disrupts lipid signaling and promotes lipid peroxidation and neurodegeneration. Lipid signaling at the neurovascular unit (neurons, astrocytes, oligodendrocytes, microglia, and cells of the microvasculature) is altered in early cerebrovascular and neurodegenerative disease. We discuss how lipid signaling regulates critical events in neuronal survival. Aberrant synaptic plasticity (e.g., epileptogenesis) is highlighted to show how gene expression may drive synaptic circuitry formation in the "wrong" direction. Docosahexaenoic acid has been implicated in memory, photoreceptor cell biogenesis and function, and neuroprotection. Free docosahexaenoic acid released in the brain during experimental stroke leads to the synthesis of stereospecific messengers through oxygenation pathways. One messenger, 10,17S-docosatriene (neuroprotectin D1; NPD1), counteracts leukocyte infiltration and proinflammatory gene expression in brain ischemia-reperfusion. In retina, photoreceptor survival depends on retinal pigment epithelial (RPE) cell integrity. NPD1 is synthesized in RPE cells undergoing oxidative stress, potently counteracts oxidative stress-triggered apoptotic DNA damage in RPE, upregulates antiapoptotic proteins Bcl-2 and Bcl-x(L), and decreases proapoptotic Bax and Bad expression. These findings expand our understanding of how the nervous system counteracts redox disturbances, mitochondrial dysfunction, and proinflammatory conditions. The specificity and potency of NPD1 indicate a potential target for therapeutic intervention for stroke, age-related macular degeneration, spinal cord injury, and other neuroinflammatory or neurodegenerative diseases.

Animals↗
PubMed1998

Regional cerebral blood flow and language dominance: SPECT during intracarotid amobarbital testing.

We examined the relation between language dominance and regional cerebral blood flow (rCBF) during the intracarotid amobarbital procedure (IAP). A previous report limited to three patients suggested that dominant rather than nondominant hemisphere IAP may have a differential effect on rCBF. Behavioral assessment during the IAP also suggests that dominant hemisphere injection results in a differential effect on memory and affective symptoms rather than nondominant injection. Thirteen patients were assessed using single-photon emission CT (SPECT) brain imaging during both left and right IAP. The SPECTs were coregistered with the individual's MRI. Changes in rCBF during each IAP were compared with the patient's baseline SPECT. Nine patients had left hemisphere dominance, two were right dominant, and two had bilateral speech representation. In the left dominant subjects, left-hemisphere injection had a consistently greater effect on rCBF than right-hemisphere injection in the anterior (p < 0.005) and posterior (p < 0.01) temporal neocortex. There was also a trend for greater hypoperfusion in the frontal lobe of the left hemisphere. rCBF in the ipsilateral hippocampus was not significantly different after each injection (p > 0.05). In the two patients with right hemisphere speech, the reverse pattern was seen, with greater hypoperfusion after right (dominant) hemisphere injection. There was no consistent asymmetry in the two patients with bilateral speech. Dominant hemisphere IAP results in significantly greater hypoperfusion than does nondominant injection. These data provide a physiologic basis for behavioral differences noted after dominant versus nondominant IAP.

Adolescent↗
PubMed1988

Diagnosis and treatment of depression in the elderly.

Depression and suicide are significant problems in the elderly, both in terms of their severity and their prevalence. It is particularly difficult to distinguish depression from early dementia, since elderly depressed patients often deny mood disorder and focus on their memory problems. This differential diagnostic dilemma is further complicated by the fact that 20 percent of Alzheimer-type dementia patients have moderate to severe depression. An even higher prevalence of depression can be seen in elderly patients with stroke or Parkinson's disease. Most all of the depressive disorders of the elderly are amenable to one form or combination of therapies: pharmacologic, electro-convulsive, or psychotherapy. Tricyclic antidepressants are often associated with adverse drug reactions in the elderly, so alternatives such as MAO inhibitors, alprazolam, bupropion and psychostimulants are currently being explored in this patient population.

Aged↗
PubMed2006

Cyclooxygenase-2 inhibition attenuates antibody responses against human papillomavirus-like particles.

Vaccination to generate protective humoral immunity against infectious disease is becoming increasingly important due to emerging strains of virus, poorly immunogenic vaccines, and the threat of bioterrorism. We demonstrate that cyclooxygenase-2 (Cox-2) is crucial for optimal Ab responses to a model vaccine, human papillomavirus type 16 virus-like particles (HPV 16 VLPs). Cox-2-deficient mice produce 70% less IgG, 50% fewer Ab-secreting cells, and 10-fold less neutralizing Ab to HPV 16 VLP vaccination compared with wild-type mice. The reduction in Ab production by Cox-2(-/-) mice was partially due to a decrease in class switching. SC-58125, a structural analog of the Cox-2-selective inhibitor Celebrex reduced by approximately 70% human memory B cell differentiation to HPV 16 VLP IgG-secreting cells. The widespread use of nonsteroidal anti-inflammatory drugs and Cox-2-selective inhibitory drugs may therefore reduce vaccine efficacy, especially when vaccines are poorly immunogenic or the target population is poorly responsive to immunization.

Animals↗
PubMed1999

Expression of L-selectin on Th1 cells is regulated by IL-12.

L-selectin has become established as a key molecule in the recirculation of naïve T cells from the blood to peripheral lymph nodes, yet little is known about its role in the migration of effector or memory cells. While differentiating naïve CD4+ T cells into Th1 and Th2 subsets in vitro, it was noted that L-selectin levels were maintained on the Th1 subset of cells. The expression of L-selectin on the Th1 cells appeared to be dependent on the presence of IL-12. Th2 cells, differentiated in the absence of IL-12, failed to maintain L-selectin expression. Coculture with IL-12, IL-18, IL-4, TNF-alpha, or IFN-alpha, -beta, or -gamma demonstrated a dependence on IL-12 alone for L-selectin expression. In addition, the inclusion of heat-killed Listeria monocytogenes in the cultures also maintained L-selectin expression on the Th1 cells. In all cultures, the maintenance of L-selectin on the T cell surface could be blocked by the inclusion of anti-IL-12 Abs. Analysis of the mRNA levels for L-selectin in T cells, differentiated in the presence or absence of IL-12, showed that the cytokine appears to exert its effect on L-selectin at the transcriptional level. Given the key role played by IL-12 in the differentiation of naïve T cells into the Th1 subset, the observation that IL-12 can also regulate L-selectin expression has implications for the migration of Th1 effector cells both through the lymphatic system and to sites of inflammation.

Adjuvants, Immunologic↗
PubMedDate not supplied

Deficits in memory tasks of mice with CREB mutations depend on gene dosage.

Studies in Aplysia, Drosophila, and mice have shown that the transcription factor CREB is involved in formation and retention of long-term memory. To analyze the impact of differential CREB levels on learning and memory, we varied the gene dosage of CREB in two strains of mutant mice: (1) CREBalphadelta mice, in which the alpha and delta isoforms are disrupted, but a third isoform beta is strongly up-regulated; (2) CREBcomp, a compound strain with one alphadelta allele and one CREBnull allele in which all CREB isoforms are disrupted. To minimize genetic background effects, CREB mutations were backcrossed into a C57BL/6 and a FVB/N strain, respectively, and studies were performed in F1 hybrids from these lines. CREBcomp but not CREBalphadelta F1 hybrids were impaired in water maze learning and fear conditioning, demonstrating a CREB gene dosage effect. However, analysis of the platform searching strategies in the water maze task suggested that CREBcomp mutants are impaired in behavioral flexibility rather than in spatial memory. In contrast to previous experiments using CREBalphadelta mice with different genetic background, the F1 hybrid CREBalphadelta and CREBcomp mice did not show deficits in a social transmission of food preference task nor in dentate gyrus and CA1 LTP as recorded from slice preparations. These data indicate that the hybrid vigor typical for F1 hybrids may compensate for a reduction in CREB levels in some tests. On the other hand, the persistence of clear behavioral deficits as shown by the F1 hybrid CREBcomp mice in water maze and fear conditioning indicates a robust and repeatable phenomenon that will permit further functional analysis of CREB.

Animals↗
PubMed2002

Development of antitumor immune responses in reconstituted lymphopenic hosts.

When naïve T cells reconstitute lymphopenic hosts, they transiently proliferate and differentiate into memory-like T cells. Here we report that tumor-specific T cells preferentially expand in tumor vaccine-draining lymph nodes after a melanoma vaccine given to RAG1 mice reconstituted with naïve T cells from normal mice. The percentage of tumor-specific Tc1 T cells detected by intracellular cytokine staining was increased approximately 4-fold in reconstituted lymphopenic hosts compared with normal hosts. Concomitantly, vaccination-induced Th1 T cells were also dramatically increased in vaccinated, reconstituted RAG1 hosts. T cells derived from reconstituted RAG1 hosts exhibited a higher level of melanoma-specific cytotoxicity in vitro. These cells were significantly more potent at mediating tumor regression in vivo after adoptive transfer into mice bearing established pulmonary metastases. Vaccination is best performed concomitantly with reconstitution; delayed vaccination resulted in T cells with less therapeutic activity.

Animals↗
PubMed1992

Lymphocyte migration through extracellular matrix.

The movement of lymphocytes through extracellular matrix (ECM) is an essential component of normal traffic and infiltration into inflammatory sites. This review surveys current knowledge of the mechanisms of lymphocyte migration through ECM, most of which was derived from work with in vitro models of basement membranes, interstitial stroma, or their constituent components. Normal lymphocyte motility is an extremely plastic property. Naive lymphocytes tend to be unresponsive to ECM components and many chemoattractants, but when exposed to antigens, artificial mitogens and certain lymphokines, they rapidly acquire locomotory capacity, which is expressed as increased polarity, adhesiveness, invasiveness and chemotactic response. Acquisition of locomotory capacity is associated with the G0/G1 transition, and activation of protein kinase C appears to be a key event. Preliminary evidence indicates that mitogenesis and differentiation to the memory phenotype trigger a long-lasting, possibly permanent elevation of locomotory response to ECM. Receptors for fibronectin, laminin and collagens I and IV have been implicated as mediators of lymphocyte motility, but these receptors have not been characterized in detail. Heparanases facilitate T cell movement through the basement membrane, but the role of proteases has not yet been defined. Major gaps remain in our understanding of the connection between in vitro models and specific stages of the infiltration process in vivo and of motility regulation at the molecular level.

Animals↗
PubMed1983

Monoclonal cytotoxic T lymphocyte hybridomas capable of specific killing activity, antigenic responsiveness, and inducible interleukin secretion.

We have recently described the production of cytotoxic T lymphocyte (CTL) hybridomas that grow continuously in culture, exhibiting constitutive, allospecific (anti-H-2b) killing activity. We now report on the response of these monoclonal CTL hybridomas to specific antigen (H-2Db) and to mitogenic lectins. Both specific antigen and T cell mitogens enhance hybridoma-mediated specific target cell killing. In addition, stimulated, but not unstimulated hybridoma cells secrete considerable amounts of IL 2 into the culture medium. Repeated cloning of the hybridomas provides strong evidence that both killing activity and IL 2 secretion can be attributed to one cell. Unfractionated Con A supernatants, containing IL 2 and other factors known to influence T cell responsiveness, or IL 2-containing media of stimulated hybridomas affect neither the growth nor the lytic activity of the hybridomas. Anti-LFA-1 monoclonal antibody, a potent inhibitor of CTL and CTL hybridoma-mediated target cell lysis, abolishes antigen- or mitogen-induced IL 2 secretion by the CTL hybridomas. Involvement of a single hybridoma receptor in antigen recognition (afferent and efferent) and in initiating IL 2 secretion is proposed. The CTL hybridomas displaying retarded killing activity before the antigenic or mitogenic stimulation appear to represent an intermediate stage in CTL differentiation, reminiscent of "memory" CTL.

Animals↗
PubMed1981

[General sensitivity disorders in temporal lobe lesions (clinical picture, pathogenesis, epilepsy syndrome significance)].

A detailed study of various kinds of general sensitivity was carried out in 70 epileptic patients with the temporal localization of the foci. In most patients examined, sensor disturbances were noted, among which latent and indistinct variants prevailed. The following disturbances of the sensitivity were specified: a) homolateral; b) contralateral; c) combined (alternating); d) of temporal genesis proper (hypo- and hyperalgesias, viscerosensor phenomena, disturbances of adaptation to pain: disturbances of the discriminative forms of sensitivity of the types of deterioration of memory, attention, collation, differentiation, "epicritic hyperesthesia", etc.); e) secondary lemniscus-involving, associated with disturbances of the afferent system functions at the trunco-diencephalic and cortical levels; f) secondary extra-lemniscus (trunco-reticular); g) sensitivity disturbances correlating with the attacks of temporal epilepsy.

Adult↗
PubMedDate not supplied

[Mechanisms involved in the prolonged humoral immune response: behavior of aphthous fever virus].

Foot and mouth disease (FMD) is a widespread infectious disease affecting cloven-hoofed animals with severe economic consequences. Animals infected with FMD virus (FMDV) develop an immunological status of immunity characterized by high titers of virus serotype-specific neutralizing antibodies (NAb) which persist for at least 18 months. In contrast, currently inactivated virus vaccines elicit lower antibody response for shorter periods. Protection against FMDV infection has been commonly related to the level of NAb in serum. The new generation vaccines are immunologically poor, and for this reason it is important that the immunological mechanisms are activated during the infection to potentiate the action of these vaccines. The objective of this review is to present the possible mechanisms involved in the long lasting humoral immune response after FMDV infection. The necessity of the Ag for the initiation of the response is well known, although its role in maintaining and regulating the immune response is still unclear. The continuous role of the Ag in maintaining the response was demonstrated in experiments in which Abs with different specificities for long periods of time without the administration of exogen Ag were detected. The capture and retention of Ab-Ag complex by dendritic follicular cells seems to be a important factor in the increase of the Ag production and in the generation of B memory cells. The genomic persistence is strongly related to the Ag persistence. During a persistent infection, in which the genome is maintained and able to synthesize proteins, the immune system would be continuously stimulated. The continuous liberation of soluble Ag, as a productive persistent infection, induces the B cells memory for its differentiation in Abs producing cells. The antigen presenting cells (APC) are cells which present the Ag to lymphocytes in the class II MHC context. Langerhans islets, dendritic, B and phagocytic cells form the APC group. The modulation of the function of the APC cells is very important in the self regulation of the immune system. The function on the immune response depends on the capacity of generating signals for the stimulation of T cells.

Animals↗