Plasticity of epidermal stem cells

The keratinocyte cell compartment in the continuously renewing epidermis of the skin is maintained by undifferentiated, self-renewing stem cells. We show that a small subpopulation of epidermal stem cells (EpiSCs) have the capacity to integrate into multiple tissues. These EpiSCs can change their phenotype in direct response of changes in cytokines in vitro, changes in cocultured cells, after injection into damaged environments in vivo. These changes appear to be unrelated to the age of the EpiSC. Even though we can isolate these cells and show that the age of thses cells appears to be irrelevant to this multipotent function, we still do not know how such cells are defined within a tissue or what the life span of a multipotent stem cell is.     

Copolymer effects on microglia and T cells in the central nervous system of humanized mice

The random amino acid copolymers FYAK and VWAK ameliorate EAE in a humanized mouse model expressing both a human transgenic myelin basic protein (MBP)85-99-specific T cell receptor and HLA-DR2. Here we show that microglia isolated from the central nervous system (CNS) of humanized mice with EAE induced by MBP85-99 and treated with these copolymers had reduced expression of HLA-DR, and thus reduced capacity to present MBP85-99 and activate transgenic T cells. In vitro microglia up-regulated empty HLA-DR2 upon activation with GM-CSF with or without LPS or IFN-gamma, but not with IL-4 or IL-10. Correspondingly, gene chip arrays showed that the CNS of untreated and YFAK-treated mice differentially expressed pro- and anti-inflammatory molecules during MBP85-99-induced EAE. Interestingly, microglia expressed the full-length gammabeta and alphabeta subunits of the tetrameric adaptor protein complexes AP-1 and AP-2 respectively, but after treatment with GM-CSF these complexes were cleaved, as had been found in immature dendritic cells derived from bone marrow. Strikingly, in vivo the perivascular lymphocyte infiltration seen in untreated mice immunized with MBP85-99 was composed of equal numbers of hVbeta2+ MPB85-99-specific transgenic and hVbeta2- endogenous T cells, while the much smaller infiltration seen after treatment with YFAK was composed predominantly of hVbeta2- endogenous T cells.     

ONSET AND TERMINAL ORIENTING RESPONSES AS A FUNCTION OF TASK DEMANDS

The frequency of response and trials to habituation of the electrodermal onset and terminal orienting response were manipulated as a function of discrimination tasks involving either stimulus content (pitch) or duration. There were no significant differences between the groups on either measure for onset ORs; however, the duration task group demonstrated more TORs and required a greater number of trials to habituate than the content task group. The results, interpreted in terms of the development of cortical models, supported Stern's suggestion that OR and TOR habituation are related to the content and duration of the stimulus respectively.     

V3 sequence analysis and biological characterization of HIV-1 isolates from asymptomatic and early symptomatic Tanzanian individuals

The aim of this study was to determine HIV-1 V3 sequences, in vitro biological characteristics and co-receptor usage of virus isolates from Tanzania. Virus was isolated from 14 of 17 samples investigated. Four of the isolates induced syncytia in MT-2 cells and used the CXCR4 co-receptor, while the remaining 10 isolates used the CCR5 co-receptor characteristic of non-MT-2 tropic viruses. One of the four MT-2 tropic isolates also used the CCR5 and CCR3 co-receptors. Proviral DNA was detected in all 14 isolates and PCR products were subjected to DNA sequencing. Unambiguous V3 amino acid sequences were obtained from 11 amplificates. Phylogenetic analysis indicated that these sequences were divergent and clustered in HIV-1 subtypes A, C or D. Sequences from the viruses that induced syncytia in MT-2 cells presented characteristic V3 phenotype-associated amino acids. Results of co-receptor analysis are in concordance with the isolate phenotype as determined by replication and induction of syncytia in MT-2 cells. The considerable diversity illustrated by a limited number of isolates from Tanzania is in accordance with reports from other regions of Africa.     

A role for hyaluronan in macrophage accumulation and collagen deposition after bleomycin-induced lung injury

Elevated concentrations of hyaluronan (HA) are associated with the accumulation of macrophages in the lung after injury. We have investigated the role of HA in the inflammatory and fibrotic responses to lung injury using the intratracheal instillation of bleomycin in rats as a model. After bleomycin-induced lung injury, both HA content in bronchoalveolar lavage (BAL) and staining for HA in macrophages accumulating in injured areas of the lung were maximal at 4 d. Increased HA in BAL correlated with increased locomotion of isolated alveolar macrophages. HA-binding peptide was able to specifically block macrophage motility in vitro. Importantly, systemic administration of HA-binding peptide to rats before injury not only decreased alveolar macrophage motility and accumulation in the lung, but also reduced lung collagen alpha (I) messenger RNA and hydroxyproline contents. We propose a model in which HA plays a critical role in the inflammatory response and fibrotic consequences of acute lung injury.     

Comparison of the direct radiolabeled antiglobulin assay and the direct immunobead binding test for detection of sperm-associated antibodies

Thirty-seven semen samples were assayed for sperm-associated IgG and IgA using the immunobead test. Portions of these sperm samples were sent for testing with a direct radiolabeled antiglobulin assay and the testing results were compared. If the results of the immunobead test when only tail-tip bead binding was noted are regarded as negative, there was close correlation between the two assay methodologies.     

Substitution of aspartic acid at beta57 with alanine alters MHC class II peptide binding activity but not protein stability: HLA-DQ (alpha1*0201, beta1*0302) and (alpha1*0201, beta1*0303)

In class II major histocompatibility complex (MHC) proteins, residue beta57 is usually aspartic acid. Alleles carrying serine, valine, or alanine at this position are strongly correlated with the development of insulin-dependent diabetes mellitus (IDDM). Asp(beta)57 participates in a conserved salt bridge that bridges the alpha and beta subunits in the peptide-binding site. It has been proposed that the correlation between IDDM and MHC alleles lacking Asp(beta)57 may be due to an instability of the protein caused by loss of this salt bridge. Using a pair of HLA-DQ proteins (alpha1*0201, beta1*0302) and (alpha1*0201, beta1*0303) differing only in having aspartic acid or alanine at position beta57, we show that the polymorphism does not have a significant effect on protein stability for either the empty or peptide-loaded forms. However, the circular dichroism spectra indicate that empty and peptide-loaded Alabeta57 proteins display slightly different secondary structures relative to their Aspbeta57 counterparts. A set of three peptides shows different binding affinities for DQ(alpha1*0201, beta1*0302) relative to DQ(alpha1*0201, beta1*0303). We propose that substitution of Asp(beta)57 residue causes a local rearrangement within the DQ peptide-binding site that alters the peptide-binding specificity. This rearrangement may help to explain the previously observed differences in SDS stability between Asp and non-Asp(beta)57 DQ proteins.     

Rey-Osterrieth Complex Figure performance in adults with attention deficit hyperactivity disorder: a validation study of the Boston Qualitative Scoring System

Rey-Osterrieth Complex Figure (ROCF) productions from 18 adults with Attention Deficit Hyperactivity Disorder (ADHD) were compared to 18 matched controls using the Boston Qualitative Scoring System (BQSS). ADHD adults showed impairment in measures of configural accuracy, planning, and neatness. A logistic regression model resulted in 75% sensitivity and 81% specificity in discriminating ADHD from control subjects. In contrast, there was no significant difference on the traditional ROCF 36-point score, and the sensitivity and specificity for the 36-point score were lower (68% and 71%, respectively). These findings suggest persisting executive dysfunction in adults with ADHD that can be detected in ROCF productions. Thus, the BQSS may be a useful tool contributing to the neuropsychological evaluation of adults with ADHD.