Biomedical subjects
L Miller
Publications and source records attributed to L Miller.
Expression of high-affinity binding of human immunoglobulin E by transfected cells.
The receptor with high affinity for immunoglobulin E (IgE) on mast cells and basophils is critical in initiating allergic reactions. It is composed of an IgE-binding alpha subunit, a beta subunit, and two gamma subunits. The human alpha subunit was expressed on transfected cells in the presence of rat beta and gamma subunits or in the presence of the gamma subunit alone. The IgE binding properties of the expressed human alpha were characteristic of receptors on normal human cells. These results now permit a systematic analysis of human IgE binding and a search for therapeutically useful inhibitors of that binding.
Complete structure and expression in transfected cells of high affinity IgE receptor.
The high-affinity receptor for immunoglobulin E, Fc epsilon RI, is found exclusively on mast cells and basophils. When multivalent allergens bind to the receptor-bound IgE, the consequent aggregation of the receptors leads to the release of mediators responsible for allergic symptoms. In rodents Fc epsilon RI is a tetrameric complex of non-covalently attached subunits: one IgE-binding alpha subunit, one beta subunit and a dimer of disulphide-linked gamma subunits. Complementary DNA encoding the alpha and the beta subunits has recently been isolated, but expression of IgE-binding by transfected cells has not yet been achieved. Here we report the cloning of cDNA for the gamma subunit, and propose a model for the alpha beta gamma 2 tetramer which accounts for many of the structural features of the receptor. The rodent receptor on the surface of COS 7 cells was expressed only when the cDNAs for all three subunits were cotransfected. Successful expression of human IgE receptors should now be possible, eventually to permit the detailed analysis of the human IgE-receptor interaction and assist the search for therapeutically effective inhibitors.
Identification of receptor-binding residues in the inflammatory complement protein C5a by site-directed mutagenesis.
C5a is an inflammatory mediator potentially involved in a number of diseases. To help define which of its 74 residues are important for receptor binding and response triggering, changes in the amino acid sequence of C5a were introduced by site-directed mutagenesis. Synthetic C5a-encoding genes incorporating point mutations were expressed in Escherichia coli, and the mutant proteins were purified to homogeneity. Modifications of the C5a molecule causing parallel reductions in binding to polymorphonuclear leukocyte membranes and in stimulation of polymorphonuclear leukocyte locomotion (chemokinesis) suggest that carboxyl-terminal residues Lys-68, Leu-72, and Arg-74 interact with the receptor. Substitutions in the disulfide-linked core of C5a revealed involvement of Arg-40 or nearby residues, because potency losses were associated with only localized conformational changes as detected by NMR. Surprisingly, a substitution at core residue Ala-26, which did not alter C5a core structure, appeared from NMR results to reduce potency by causing a long-distance conformational change centered on residue His-15. Thus, at least three discontinuous regions of the C5a molecule appear to act in concert to achieve full potency.
Stress, satisfaction, and coping: a study of women clerical workers.
Increasing numbers of women in the work force have prompted researchers to study the health impact of their work satisfactions and stressors. In this study, we examined the quality of the work role as perceived by women who hold clerical jobs. Qualitative data were collected through structured interviews with 87 female clerical workers employed in four organizational settings. All were mothers with one or more children living at home. Work satisfaction, work stressors, coping strategies, and resources were discussed in the interviews. Categories were developed for each of these areas. The Ethnograph computer program was used after content analysis to code and retrieve the responses for each category.
Thyroid hormone induces constitutive keratin gene expression during Xenopus laevis development.
We have used in vitro explant cultures of Xenopus laevis skin to investigate the role that the thyroid hormone triiodothyronine (T3) plays in activating the 63-kilodalton (kDa) keratin genes. The activation of these genes in vivo requires two distinct steps, one independent of T3 and one dependent on T3. In this report we have shown that the same two steps are required to fully activate the 63-kDa keratin genes in skin explant cultures, and we have characterized the T3-mediated step in greater detail. Unlike the induction of transcription by T3 or steroid hormones in adult tissues, there was a long latent period of approximately 2 days between the addition of T3 to skin cultures and an increase in concentration of keratin mRNA. While the T3 induction of 63-kDa keratin gene transcription cannot occur until age 48, a short transient exposure of stage 40 skin cultures to T3 resulted in high-level expression of these genes 5 days later, when normal siblings had reached stage 48. This result indicates that T3 induces a stable change in epidermal cells which can be expressed much later, after extensive cell proliferation has occurred in the absence of T3. Once the 63-kDa keratin genes were induced, they were stably expressed, and by the end of metamorphosis T3 had no further effect on their expression. The results suggest that T3 induces constitutive expression of the 63-kDa keratin genes during metamorphosis.
Malignant canine anterior uveal melanoma.
Explore the source record for details and available documents.
Cerebellar atrophy caused by high-dose cytosine arabinoside: CT and MR findings.
Explore the source record for details and available documents.
On the neuropsychology of dreams.
Explore the source record for details and available documents.
The receptor with high affinity for IgE.
The cDNAs for each of the three types of polypeptide that form the high affinity IgE receptor have been cloned and sequenced. Analysis of the predicted amino acid sequence and other data suggests that the four-chained structure (alpha beta gamma 2) contains seven transmembrane segments. The alpha chain resembles the immunoglobulin-binding chain found in other Fc receptors, but the beta and gamma chain sequences do not resemble other known proteins. (The one exception: the transmembrane segment of the gamma chains, which is homologous to the corresponding segment of the zeta chain of the CD3 complex found on T lymphocytes). Efficient expression of IgE binding by the rat receptor in COS cells was observed only when the coding sequences for each of the three chains were co-transfected. So far, only the cDNA for the human alpha chain has been successfully cloned. We attempted to express this chain by co-transfecting its cDNA with those for the rat beta and gamma chains. Surprisingly, co-transfection with the cDNA for the gamma chain was sufficient, although when the beta and gamma chains were both co-transfected, expression of alpha beta gamma oligomers was evident. Approaches being used to define by genetic manipulation the functional role of various parts of the receptor are discussed.
Caution crucial in diastema upkeep.
Explore the source record for details and available documents.
Polymerization of actin modified with fluorescein isothiocyanate.
Solution properties of skeletal muscle actin, modified at lysine-61 with fluorescein isothiocyanate (FITC) [Burtnick, L.D. (1984) Biochim. Biophys. Acta 791, 57-62], were re-examined in this work by light scattering, analytical ultracentrifugation, fluorescence, electron microscopy and myosin ATPase activity measurements. Fluorescence measurements using trace amounts of actin labeled with N-(1-pyrenyl)iodoacetamide showed that the FITC modification inhibited but did not block completely the polymerization of actin by KCl and MgCl2. Sedimentation velocity runs of FITC-actin, incubated with 100 mM KCl and 2 mM MgCl2, revealed the presence in these solutions of polymeric, oligomeric and monomeric species. The critical concentration for FITC-actin polymerization under these conditions was 12 microM. As judged by electron microscopy, FITC-actin polymers were similar to but generally shorter than standard F-actin filaments. Light scattering measurements indicated that FITC modification inhibited also the polymerization of actin by myosin subfragment 1 (S1) but the resulting complexes were indistinguishable from standard, decorated actin filaments. MgATPase measurements showed that FITC-actin, polymerized by preincubation with S1, activated the MgATPase activity of S1 while the monomeric labeled protein did not. Thus, in analogy to native actin, the activating function of FITC-actin depended on the formation of actin filaments. Results presented in this study suggest that the region around lysine-61 of actin plays an important role in actin-actin contact and is less crucial to actomyosin interaction.
Antigenic variation among group A streptococcal M proteins. Nucleotide sequence of the serotype 5 M protein gene and its relationship with genes encoding types 6 and 24 M proteins.
The 1479-base pair (bp) nucleotide sequence of the serotype 5 M protein gene (smp5) from Streptococcus pyogenes contains three distinct types of tandemly repeated sequences, designated A, B, and C. Repeat A (21 bp x 6, in the 5'-half of smp5), shares no homology with the types 6 or 24 M protein genes (Hollingshead, S. K., Fischetti, V. A., and Scott, J. R. (1986) J. Biol. Chem. 261, 1677-1686; Mouw, A. R., Beachey, E. H., and Burdett, V. (1988) J. Bacteriol., in press). Repeat B (75 bp x 3.6, in the center of smp5) is also present in the M6, but not in the M24 gene. Repeat C (105 bp x 2.7, just distal to the B repeats) shares homology with repeats in both the M6 and M24 genes. All three genes share extensive homology in their 3'-halves and in 5' sequences encoding the N-terminal signal peptides, but between these two regions there are highly variable sequences that are responsible for antigenic diversity. These relationships suggest that both intergenic and intragenic recombination has occurred during the evolution of distinct M protein serotypes. All three M proteins contain conserved hydrophobic and proline-rich sequences at their C-terminal ends, suggestive of a membrane anchor and a peptidoglycan spanning region.
Polymerization of G-actin by myosin subfragment 1.
The polymerization of actin from rabbit skeletal muscle by myosin subfragment 1 (S-1) from the same source was studied in the depolymerizing G-actin buffer. The polymerization reactions were monitored in light-scattering experiments over a wide range of actin/S-1 molar rations. In contrast to the well resolved nucleation-elongation steps of actin assembly by KC1 and Mg2+, the association of actin in the presence of S-1 did not reveal any lag in the polymerization reaction. Light scattering titrations of actin with S-1 and vice versa showed saturation of the polymerization reaction at stoichiometric 1:1 ratios of actin to S-1. Ultracentrifugation experiments confirmed that only stoichiometric amounts of actin were incorporated into a 1:1 acto-S-1 polymer even at high actin/S-1 ratios. These polymers were indistinguishable from standard complexes of S-1 with F-actin as judged by electron microscopy, light scattering measurements, and fluorescence changes observed while using actin covalently labeled with N-(1-pyrenyl)iodoacetamide. F-actin obtained by polymerization of G-actin by S-1 could initiate rapid assembly of G-actin in the presence of 10 mM KC1 and 0.5 mM MgCl2 and showed normal activation of MgATPase hydrolysis by myosin.
Interaction in families with obese children.
In a controlled study using recently developed and validated methods for eliciting and describing family interactions, a characteristic dysfunctional pattern of interaction was found in families with an obese child. The pattern differed from patterns predicted by previous workers on the basis of indirect evidence or non-systematic study. The pattern was present in all the families studied, but was more marked in the sub-group recruited from a local school, than from subgroups recruited through medical sources. This sub-group had a more positive attitude to obesity and a slightly lower degree of obesity. No common or characteristic interactional pattern was found in the controls. The results were not explainable in terms of demographic criteria, family structure or composition variables, or family emotional health. The findings are discussed in relation to a model of obesity as a family syndrome and a manifestation of psychosocial identity.
A prospective study of titanium ventilation tubes.
A prospective controlled study was undertaken in which in 100 children a titanium ventilation tube was inserted in one ear, and a Paparella silicone tube was inserted in the contralateral ear as a control. The tubes were evaluated with respect to length of time of intubation, episodes of otorrhea, and early occlusion. Sixty-five patients were followed for at least one year, or until both tubes had extruded. Long-term follow-up of these patients has revealed little difference in the incidence of tube occlusion, early extrusion, or infection with otorrhea. Since the titanium tube is more than twice as expensive and has no proven advantages over a silicone tube of similar design, we have no reason to recommend its use over the less costly, standard silicon ventilation tube.
Biologic characteristics and treatment of acute nonlymphocytic leukemia in children. Report of the ANLL Strategy Group of the Childrens Cancer Study Group.
Today approximately 75 per cent of children with ANLL can be induced into a complete remission and approximately 40 per cent will have an event-free survival for more than 3 years, irrespective of whether they received a bone marrow transplantation or chemotherapy after induction. In order to achieve these results very intensive therapy is required. The morbidity and mortality of treatment are high. The length of therapy needed after induction of remission is not known. Whether or not maintenance therapy is required is perhaps related most directly to the intensity of the therapy employed. Similarly, the role of bone marrow transplantation in patients in first remission, treatment of CNS leukemia, and treatment of chloromas are controversial. There is general agreement that WBCs over 100,000, acute monoblastic leukemia in infants less than 2 years of age, and certain chromosomal abnormalities are associated with a poor prognosis. Although there has been a dramatic improvement in the treatment of ANLL over the past 15 years, stratification of therapy based on biologic parameters, and alteration of treatment based on the early responses to treatment may be required before further advances will be made.
The impact of occupation, performance, and sex on sex role stereotyping.
Explore the source record for details and available documents.