Functional wrist motion.
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Activities of Daily Living↗
Biomedical subjects
D L Nelson
Publications and source records attributed to D L Nelson.
Temporal variability in immunological parameters: peripheral blood mononuclear cell subsets, serum immunoglobulins, and soluble markers of immune system activation.
T-cell subsets and soluble factors of immune system activation are increasingly used as biologic markers of disease and predictors of disease progression. For example, changes in CD4 cells and CD4:CD8 ratio, sIL-2R, B2M, neopterin, and IgA have been used in predicting AIDS onset and progression. We examined the temporal variability of T-cell subsets, monocytes, natural killer cells, B cells, immunoglobulins, soluble interleukin-2 receptor (sIL-2R), neopterin, and beta-2 microglobulin (B2M) among 135 adults tested at two time points approximately 3 months apart. The purpose of the study was two-fold: (1) to assess the stability of these measures at two points in time, and (2) to investigate which parameters tend to track together over time, i.e., show significant longitudinal correlation. Mean population values for these immunologic parameters remained remarkably stable over the 3-month period. However, individual subjects exhibited significant temporal variability for many parameters. Unlike observations in patients with AIDS, changes in immunoglobulins and other soluble factors were not significantly correlated with changes in cellular subsets over the same period. However, change in B2M was correlated with change in neopterin (r = .35, p < or = .0001), and change in IgA was correlated with changes in IgG and IgM (r = .44, r = .54, P < or = .001 for both). Characterizing this temporal variability in a healthy population provides important information for researchers applying these tests in clinical and epidemiological studies.
Adult↗
In vitro and in vivo biochemistry of olanzapine: a novel, atypical antipsychotic drug.
BACKGROUND: Classical (typical) antipsychotic drugs are in wide use clinically, but some patients do not respond at all to treatment, while in others, negative symptoms and cognitive deficits fail to respond. Also, these drugs often cause serious motor disturbances. Clozapine, an atypical antipsychotic, appears to correct many of these deficiencies, but has a significant incidence of potentially fatal agranulocytosis. Accordingly, we attempted to develop a prototype of a new generation of antipsychotics that is both more efficacious and safe. Our strategy was to create a compound that is not only active in behavioral tests that predict antipsychotic action but also shares the rich, multifaceted receptor pharmacology of clozapine without its side effects. To this end, Eli Lilly and Co. developed olanzapine. In this article we characterize the in vitro and in vivo receptor pharmacology of olanzapine. METHOD: We evaluated olanzapine interactions with neuronal receptors using standard assays of radioreceptor binding in vitro and well-established in vivo (functional) assays. RESULTS: Binding studies showed that olanzapine interacts with key receptors of interest in schizophrenia, having a nanomolar affinity for dopaminergic, serotonergic, alpha 1-adrenergic, and muscarinic receptors. In vivo olanzapine is a potent antagonist at DA receptors (DOPAC levels; pergolide-stimulated increases in plasma corticosterone) and 5-HT receptors (quipazine-stimulated increases in corticosterone), but is weaker at alpha-adrenergic and muscarinic receptors. Olanzapine has little or no effect at other receptors, enzymes, or key proteins in neuronal function. Olanzapine has a receptor profile that is similar to that of clozapine: it is relatively nonselective at dopamine receptor subtypes and it shows selectivity for mesolimbic and mesocortical over striatal dopamine tracts (electrophysiology; Fos). CONCLUSION: The binding and functional profile of olanzapine (1) is similar to that of clozapine, (2) indicates that olanzapine is an atypical antipsychotic drug, and (3) is consistent with clinical efficacy. If olanzapine also proves to be safe, then it will have high potential to become a more ideal antipsychotic drug.
Animals↗
CD80 (B7.1) and CD54 (intracellular adhesion molecule-1) induce target cell susceptibility to promiscuous cytotoxic T cell lysis.
Overexpression of B7 and intracellular adhesion molecule-1 (ICAM-1) on syngeneic cells triggered MHC-unrestricted lysis by MHC-restricted CD8+ CTL without TCR/CD3 engagement. Both CD28/B7 and LFA-1/ICAM-1 interactions were required for MHC-nonrestricted cytotoxicity. Cytotoxicity was measured in 4-h and 16- to 18-h cytotoxicity assays. B7-ICAM-1 overexpression triggered perforin- and Fas ligand-mediated lysis, while TNF-alpha was not elicited in MHC-unrestricted cytotoxicity. These results suggest that target cells may elicit MHC-unrestricted lysis from CTL through up-regulation of membrane adherence and costimulatory receptors.
Animals↗
Identification of regions of the Wiskott-Aldrich syndrome protein responsible for association with selected Src homology 3 domains.
Src homology 3 (SH3) domains have been shown to mediate selected interactions between signaling molecules and are essential for the activation of a number of receptor-driven pathways. The Wiskott-Aldrich syndrome protein was identified as a protein that associated selectively with the SH3 domains derived from c-Src, p85alpha, phospholipase Cgamma1, and c-Fgr. Significantly reduced association was detected to the N-terminal SH3 domain and the tandem SH3 domains of p47(phox), and no binding was detected to the SH3 domain of n-Src, the C-terminal SH3 domain of p47(phox), or either of the SH3 domains of p67(phox). Three peptides corresponding to potential Wiskott-Aldrich syndrome protein SH3 domain binding motifs were found to inhibit its association with c-Src, Fgr, and phospholipase Cgamma1 SH3 domains, but not the p85alpha SH3 domain. These peptides have the sequences MRRQEPLPPPPPPSRG, TGRSGPLPPPPPGA, and KGRSGPLPPVPLGI and show homology with other SH3 domain binding motifs. It is possible that the intracellular association of Wiskott-Aldrich syndrome protein with other signaling proteins is mediated by its SH3 domain-binding regions, and this may play a role in its putative function as a regulatory molecule in immune cells.
Amino Acid Sequence↗
Dihydrobenzofuran analogues of hallucinogens. 3. Models of 4-substituted (2,5-dimethoxyphenyl)alkylamine derivatives with rigidified methoxy groups.
Tetrahydrobenzodifuran functionalities were employed as conformationally restricted bioisosteres of the aromatic methoxy groups in prototypical hallucinogenic phenylalkylamines 1 and 2. Thus, a series of 8-substituted 1-(2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b']difuran-4-yl)-2-aminoal kanes (7a-e) were prepared and evaluated for activity in the two-lever drug discrimination paradigm in rats trained to discriminate saline from LSD tartrate (0.08 mg/kg) and for the ability to displace [3H]ketanserin from rat cortical homogenate 5-HT2A receptors and [3H]-8-OH-DPAT from rat hippocampal homogenate 5-HT1A receptors. In addition, 1-(8-bromo-2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b']difuran-4-yl)-2-am inopropane (7b), which was found to be extremely potent in the rat in vivo assays, was evaluated for its ability to compete with [125I]DOI and [3H]ketanserin binding to cells expressing cloned human 5-HT2A, 5-HT2B, and 5-HT2C receptors. All of the dihydrofuranyl compounds having a hydrophobic substituent para to the alkylamine side chain had activities in both the in vitro and in vivo assays that equaled or surpassed the activity of the analogous conformationally flexible parent compounds. For example, 7b substituted for LSD in the drug discrimination assay with an ED50 of 61 nmol/kg and had Kj values in the nanomolar to subnanomolar range for the displacement of radioligand from rat and human 5-HT2 receptors, making it one of the most potent hallucinogen-like phenylalkylamine derivatives reported to date. The results suggest that the dihydrofuran rings in these new analogues effectively model the active binding conformations of the methoxy groups of the parent compounds 1 and 2. In addition, the results provide information about the topography and relative orientation of residues involved in agonist binding in the serotonin 5-HT2 receptors.
8-Hydroxy-2-(di-n-propylamino)tetralin↗
Genetic variation and evolutionary stability of the FMR1 CGG repeat in six closed human populations.
In an attempt to understand the allelic diversity and mutability of the human FMR1 CGG repeat, we have analyzed the AGG substructure of this locus within six genetically-closed populations (Mbuti pygmy, Baka pygmy, R. surui, Karitiana, Mayan, and Hutterite). Most alleles (61/92 or 66%) possessed two AGG interspersions occurring with a periodicity of one AGG every nine or ten CGG repeats, indicating that this pattern is highly conserved in all human populations. significant differences in allele distribution were observed among the populations for rare variants possessing fewer or more AGG interruptions than the canonical FMR1 CGG repeat sequence. Comparisons of expected heterozygosity of the FMR1 CGG repeat locus with 30 other microsatellite loci, demonstrated remarkably similar levels of polymorphism within each population, suggesting that most FMR1 CGG repeat alleles mutate at rates indistinguishable from other microsatellite loci. A single allele (1 out of 92) was identified with a large uninterrupted tract of pure repeats (42 pure CGG triplets). Retrospective pedigree analysis indicated that this allele had been transmitted unstably. Although such alleles mutate rapidly and likely represent evolving premutations, our analysis suggests that in spite of the estimated frequency of their occurrence, these unstable alleles do not significantly alter the expected heterozygosity of the FMR1 CGG repeat in the human population.
Biological Evolution↗
Potent, selective tetrahydro-beta-carboline antagonists of the serotonin 2B (5HT2B) contractile receptor in the rat stomach fundus.
A series of potent, selective 5HT2B receptor antagonists has been identified based upon yohimbine, with SAR studies resulting in a 1000-fold increase in 5HT2B receptor affinity relative to the starting structure (-log KBS > 10.0 have been obtained). These high-affinity tetrahydro-beta-carboline antagonists are able to discriminate among the 5HT2 family of serotonin receptors, with members of the series showing selectivities of more than 100-fold versus both the 5HT2A and 5HT2C receptors based upon radioligand binding and functional assays. As the first compounds reported with such selectivity and enhanced receptor affinity, these tetrahydro-beta-carboline antagonists are useful tools for elucidating the role of serotonin acting at the 5HT2B receptor in normal and disease physiology.
Animals↗
Studies of the expression of the Wiskott-Aldrich syndrome protein.
The Wiskott-Aldrich syndrome (WAS) is an X-linked disorder characterized by thrombocytopenia, eczema, disorders in cell-mediated and humoral immunity, and a proclivity to lymphoproliferative disease. The gene responsible encodes a 53-kD proline-rich protein of unknown function (WASP). We produced a FLAG-WASP fusion protein that was used to immunize mice and produce mAbs against WASP. Using monoclonal anti-WASP in Western immunoblots, we have determined that WASP is present in the cytoplasmic but not nuclear fraction of normal human peripheral blood mononuclear cells, in normal human platelets, in T lymphocytes, non-T lymphocytes, and monocytes. The protein is produced in the B cell immunoblastic cell line DS-1, in normal EBV-transformed B cell lines, and in HEL92.1.7, but is barely detectable in MOLT-4 and not detectable in K562. WASP was present in two of four EBV-transformed cell lines from WAS patients. Splenic tissue immunostaining was performed in two patients, and the results correlated with the results of the Western blots. Sequence analysis of WASP cDNA from two patients who produce WASP show mutations causing amino acid substitutions. These studies establish a foundation for further studies aimed at understanding the function of WASP.
Amino Acid Sequence↗
IL-15 induces the release of soluble IL-2Ralpha from human peripheral blood mononuclear cells.
The recently identified and cloned cytokine IL-15 shares many of the T-cell and B-cell stimulatory activities of IL-2 and utilizes the beta and gamma chains of the IL-2R for binding and signaling. The present report shows that, like IL-2, IL-15 in a concentration and time-dependent manner causes the release of sIL-2Ralpha from PHA-activated human peripheral blood mononuclear cells. This effect of IL-15 is largely direct and independent of IL-2. Blocking of the IL-2Rbeta chain with the antibody Mik-beta1 prevented the release of sIL-2Ralpha by IL-15 but not by IL-2. IL-7, another cytokine utilizing the gamma chain of the IL-2R, drove the release of sIL-2Ralpha as well. Several clinical conditions are associated with abnormal serum sIL-2Ralpha levels and are also monitored by the measurement of sIL-2Ralpha. The reason for sIL-2Ralpha release is not fully understood. In this study, IL-15, like IL-2 was shown to be a potent inducer of sIL-2Ralpha release in vitro.
Antibodies, Monoclonal↗
Release of sIL-2R alpha from and activation of native human peripheral blood mononuclear cells by recombinant IL-15.
The cytokine interleukin (IL)-15 shares several activities with IL-2. Both cytokines induced expression of cell-surface IL-2R alpha (CD25) on freshly isolated human peripheral blood mononuclear cells (PBMC) in the absence of other exogenous stimuli. They also stimulated the release of soluble IL-2R alpha and induced proliferation of these cells in 1-week cultures in a time- and dose-dependent manner. Recombinant IL-7 could also induce the expression of CD25, although sIL-2R alpha was released at only low levels. In monocyte-depleted PBMC the sIL-2R alpha release was minimal. When isolated T cells or non-T cells were stimulated by rIL-15 or rIL-2, cell surface CD25 was expressed, but released sIL-2R alpha was undetectable. On stimulation with rIL-15, more than 80% of all natural killer cells expressed CD25 and more CD8br+ lymphocytes were positive for CD25 compared to stimulation by rIL-2. These results may be clinically relevant because several diseases are associated with high serum levels of sIL-2R alpha which may he not only due to IL-2 but also due to IL-15 stimulation.
Cell Division↗
Receptor subtype and density determine the coupling repertoire of the 5-HT2 receptor subfamily.
The 5-Hydroxytryptamine (5-HT)2C receptor (originally known as the 5-HT1C receptor) is a member of the 5-HT2 subfamily of G protein coupled receptors, which is known to couple to phospholipase C. Within the 5-HT2 subfamily, only the 5-HT2C receptor also coupled to inhibition of forskolin-stimulated cAMP production when expressed at high density (12 pmol/mg membrane protein) in stably transformed AV12 cells. The 5-HT2C receptor coupled with high efficacy to both phospholipase C as measured by IP3 (inositol 1,4,5-trisphosphate) production and to inhibition of forskolin-stimulated cAMP production (EC50 = 2.98 nM +/- 0.9 and IC50 = 47.99 nM +/- 10.25 respectively). The 5-HT2A and 5-HT2B receptors, while coupling to phospholipase C with high affinity (EC50s of 19.24 nM +/- 6.44 and 1.24 nM +/- 0.136 respectively), did not decrease adenylyl cyclase activity. The 5-HT2C receptor actions in both systems showed the expected pharmacology for the 5-HT2C receptor, e.g., mesulergine antagonized the effects of 5-HT and spiperone did not. Preincubation of cells with PTX showed that the G protein coupling of the 5-HT2C receptor to phospholipase C is PTX insensitive, while the G protein coupling to inhibition of adenylyl cyclase is PTX sensitive, even to concentrations as low as 20 ng/ml of PTX. PTX pretreatment of the 5-HT2C bearing cells also unmasked a small stimulatory effect on adenylyl cyclase. When expressed at low density the 5-HT2C receptor potentiated forskolin-stimulated cAMP production by 2 fold while still maintaining its ability to enhance PI hydrolysis. A more modest potentiation of cAMP production was noted with low density expression of the 5-HT2B receptor. Thus the ability of the 5-HT2C receptor to interact with several effectors through at least two different G proteins is, in part, receptor subtype specific but also influenced by receptor density.
Animals↗
A novel class of 5-HT2A receptor antagonists: aryl aminoguanidines.
Local delivery of serotonin (5-HT) produces a rapid edematous response in soft tissues via increased fluid extravasation which is prevented by 5-HT2 antagonists such as ketanserin or mianserin. Here we report the effects of a new class of aminoguanidine 5-HT2 antagonists, with relative selectivity for 5-HT2A receptors which are potent inhibitors of 5-HT-induced paw edema in the rat. Radioligand binding studies with 125I DOI on human 5-HT2A and 5-HT2C receptors and with 3H-5-HT on human 5-HT2B receptors demonstrated that, LY314228, and LY320954 displayed some selectivity for the 5-HT2A receptor. When compared to binding at other 5-HT2 receptor subtypes, LY314228 had an 18.6-fold greater affinity for the 5-HT2A site over the 5-HT2B site, and 2.6 fold greater at the 5-HT2C site. LY320954 displayed similar preference for 5-HT2A sites. Both compounds also inhibited 5-HT-induced paw swelling in rats, with ED50's of 6.4 and 4.8 mg/kg (for LY314228 and LY320954, respectively). These studies offer evidence for a novel class of pharmacophores for the 5-HT2 receptor family which show greater relative affinities for the 5-HT2A receptor subclass.
Animals↗
Identification of FMR2, a novel gene associated with the FRAXE CCG repeat and CpG island.
Five folate-sensitive fragile sites have been identified at the molecular level to date. Each is characterized by an expanded and methylated trinucleotide repeat CGG (CCG). Of the three X chromosome sites, FRAXA, FRAXE and FRAXF, the former two are associated with mental retardation in their expanded forms. FRAXA expansion results in fragile X syndrome due to down regulation of expression of the FMR1 gene, which carries the hypermutable CGG repeat in the 5' untranslated portion of its first exon. Mild mental retardation without consistent physical findings has been found associated with expanded CCG repeats at FRAXE. We have identified a large gene (FMR2) transcribed distally from the CpG island at FRAXE, and down-regulated by repeat expansion and methylation. The gene is novel, expressed in adult brain and placenta, and shows similarity with another human protein, MLLT2, expressed from a gene at chromosome 4q21 involved in translocations found in acute lymphoblastic leukaemia (ALL) cells. Identification of this gene will facilitate further studies to determine the role of its product in FRAXE associated mental deficiency.
Adult↗
Selection against mutant alleles in blood leukocytes is a consistent feature in Incontinentia Pigmenti type 2.
Incontinentia Pigmenti 2 (IP2) is an X-linked dominant disorder with male lethality. Affected females display a characteristic skin eruption that evolves through four classic stages, frequently accompanied by dental and retinal abnormalities. Non-random (skewed) X-inactivation in peripheral blood leukocytes and in fibroblasts has been observed in females with IP2; however, sample sizes have been small and methods of analysis varied. We have examined X-inactivation in a large group of multigenerational IP2 families, in smaller families, and in isolated cases. Ninety-eight percent of affected females in multigenerational IP2 pedigrees show completely skewed patterns of X-inactivation, while only approximately 10% of a normal control population is skewed. Results both in small families and in new mutation cases with subsequent segregation consistent with Xq28 linkage are similar. Isolated cases show a lower percentage (85%) of skewed affected individuals; this difference may be due to inaccurate clinical ascertainment. The parent of origin of new mutations could be determined in 15 families; paternal new mutations were twice as common as maternal. Fibroblast subclones from a biopsy at the boundary of a skin lesion in a newborn IP2 patient were isolated, and clones with either one or the other X active were identified, demonstrating that cells with the active disease-bearing X chromosome are still present in stage I skin lesions.
Adult↗
Haplotype and interspersion analysis of the FMR1 CGG repeat identifies two different mutational pathways for the origin of the fragile X syndrome.
To understand the origins of the fragile X syndrome and factors predisposing alleles to instability and hyperexpansion, we have compared the haplotype (using markers FRAXAC1, FRAXAC2, and DXS548) and AGG interspersion patterns of the FMR1 CGG repeat for 214 normal and 16 premutation chromosomes. Association testing between interspersion pattern and haplotype reveals a highly significant (P < 0.002) non-random distribution, indicating that all three markers are useful in phylogenetic reconstruction of mutational change. Parsimony analysis of the FMR1 CGG repeat substructure predicts that loss of AGG interruptions has occurred independently on many haplotypes associated with the fragile X syndrome, partially explaining the haplotype diversity of this disease. Among haplotypes found in linkage disequilibrium with the fragile X mutation, two different modes of mutation and predisposition to instability have been identified. One pathway has involved the frequent and recurrent loss of AGG interruptions from rare asymmetrical ancestral array structures. Intergenerational transmission studies suggest that these predisposed chromosomes progress relatively rapidly to the disease state. In contrast, the second mutational pathway involves a single haplotype which has maintained two AGG interruptions. Parsimony analysis of CGG repeat substructure within this haplotype suggests that larger alleles have been generated by gradual increments of CGG repeats distal to the most 3' interruption. Pedigree analysis of the intergenerational stability of alleles of this haplotype confirms a gradual progression toward instability thresholds. As a result, a large reservoir of chromosomes carrying large repeats on this haplotype exists. These chromosomes are predisposed to disease. The present data support a model in which there are at least two different mutational pathways predisposing alleles to instability and hyperexpansion associated with the fragile X syndrome.
Alleles↗
Duplication of a gene-rich cluster between 16p11.1 and Xq28: a novel pericentromeric-directed mechanism for paralogous genome evolution.
We have identified a 26.5 kb gene-rich duplication shared by human Xq28 and 16p11.1. Complete comparative sequence analysis of cosmids from both loci has revealed identical Xq28 and 16p11.1 genomic structures for both the human creatine transporter gene (SLC6A8) and five exons of the CDM gene (DXS1357E). Overall nucleotide similarity within the duplication was found to be 94.6%, suggesting that this interchromosomal duplication occurred within recent evolutionary time (7-10 mya). Based on comparisons between genomic and cDNA sequence, both the Xq28 creatine transporter and DXS1357E genes are transcriptionally active. Predicted translation of exons and RT-PCR analysis reveal that chromosome 16 paralogs likely represent pseudogenes. Comparative fluorescent in situ hybridization (FISH) analyses of chromosomes from various primates indicate that this gene-rich segment has undergone several duplications. In gorilla and chimpanzee, multiple pericentromeric localizations on a variety of chromosomes were found using probes from the duplicated region. In other species, such as the orangutan and gibbon, FISH signals were only identified at the distal end of the X chromosome, suggesting that the Xq28 locus represents the ancestral copy. Sequencing of the 16p 11.1/Xq28 duplication breakpoints has revealed the presence of repetitive immunoglobulin-like CAGGG pentamer sequences at or near the paralogy boundaries. The mobilization and dispersal of this gene-rich 27 kb element to the pericentromeric regions of primate chromosomes defines an unprecedented form of recent genome evolution and a novel mechanism for the generation of genetic diversity among closely related species.
Animals↗
A comparison of performance in added-purpose occupations and rote exercise for dynamic standing balance in persons with hemiplegia.
OBJECTIVES: Adding purpose to daily occupations to promote performance is a basic premise of occupational therapy. This study investigated the hypothesis that in persons with hemiplegia, two added-purpose occupations would elicit more exercise repetitions than a rote exercise. METHOD: In a counterbalanced order, 21 subjects with hemiplegia, aged 51 to 78 years, experienced all three conditions of a dynamic standing balance exercise that involved bending down, reaching, standing up, and extending the arm. One condition of added purpose involved the use of materials (small balls and target); a second added-purpose condition involved the subjects' imagination of the small balls. The third condition was the rote exercise without added purpose. RESULTS: A one-way analysis of variance for related measures indicated that the subjects performed significantly differently in each of the three conditions (p < .001). A Tukey multiple comparison test revealed that the subjects did significantly more exercise repetitions in the added-materials condition and in the imagery-based condition than in the rote exercise condition (p < .05). CONCLUSION: This study demonstrates how added purpose can enhance motor performance in persons with hemiplegia. Purpose may be effectively added to an exercise through the use of materials or imagery.
Aged↗