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Biomedical subjects

M Wright

Publications and source records attributed to M Wright.

At least 73 records · Page 4Linked to original sources
PubMed2000

cDNA cloning and functional analysis of a truncated STAT5a protein from autonomously growing FDCP-1 cells.

The transcription factor STAT5 is activated by multiple hematopoietic cytokine receptors and has been implicated in the induction of cellular processes such as differentiation, proliferation and antiapoptotic activities. Here, we report cloning of the cDNA and characterization of a mutant STAT5a protein that is expressed in interleukin-3 (IL-3)-independently growing FDCP-1 cells. Analysis of the cDNA revealed a deletion of both the transactivation and the SH2 domains. Stable expression of the protein in parental IL-3-dependent cells results in elevated DNA binding activity of wild type (WT)-STAT5 in the nucleus, enhanced growth rates and a reduced susceptibility to undergo apoptosis after withdrawal of IL-3. Although the protein is not present in DNA/protein complexes in the nucleus, we observed pronounced effects on IL-3-induced signal transduction. The results suggest competition of the mutant protein with cytosolic mechanisms regulating STAT5 activity. In conclusion, the data support the hypothesis of an involvement of STAT5 in mitogenic and antiapoptotic signaling.

Amino Acid Sequence↗
PubMed2000

Mutations in a new gene in Ellis-van Creveld syndrome and Weyers acrodental dysostosis.

Ellis-van Creveld syndrome (EvC, MIM 225500) is an autosomal recessive skeletal dysplasia characterized by short limbs, short ribs, postaxial polydactyly and dysplastic nails and teeth. Congenital cardiac defects, most commonly a defect of primary atrial septation producing a common atrium, occur in 60% of affected individuals. The disease was mapped to chromosome 4p16 in nine Amish subpedigrees and single pedigrees from Mexico, Ecuador and Brazil. Weyers acrodental dysostosis (MIM 193530), an autosomal dominant disorder with a similar but milder phenotype, has been mapped in a single pedigree to an area including the EvC critical region. We have identified a new gene (EVC), encoding a 992-amino-acid protein, that is mutated in individuals with EvC. We identified a splice-donor change in an Amish pedigree and six truncating mutations and a single amino acid deletion in seven pedigrees. The heterozygous carriers of these mutations did not manifest features of EvC. We found two heterozygous missense mutations associated with a phenotype, one in a man with Weyers acrodental dysostosis and another in a father and his daughter, who both have the heart defect characteristic of EvC and polydactyly, but not short stature. We suggest that EvC and Weyers acrodental dysostosis are allelic conditions.

Alternative Splicing↗
PubMed2000

The Child Health Questionnaire in Australia: reliability, validity and population means.

OBJECTIVE: To provide reliability, validity and population means for the Australian Authorized Adaptation of the parent-report Child Health Questionnaire (CHQ). METHOD: We surveyed a representative sample of Australian parents of school-aged children (5-18 years) in Victoria between July and December 1997, using a school-based cluster sample design stratified by educational sector and age. RESULTS: Some 5,414 parents responded (72%). Good psychometric performance was observed for the CHQ in Australia. Population means demonstrated differences in health on domains of functioning and well-being by age and gender. This population-derived sample demonstrated high ceiling values on Physical Functioning and Social Role scales. IMPLICATIONS: The CHQ appears to be a reliable and valid measure of child and adolescent functional health and well-being for the Australian population. Child health outcomes of children and adolescents with particular conditions or within population subgroups can be compared with these age and gender benchmarks. Appropriate uses for the CHQ may be to discriminate between children who are generally healthy and children with health problems, or in population surveys partnered with measures that extend the range of physical functioning and social functioning.

Activities of Daily Living↗
PubMed2000

Influence of parental gender and self-reported health and illness on parent-reported child health.

BACKGROUND: Although there is clear evidence of the influence of parental factors on child health outcomes, the influence of parental perceptions of their health and illness on the reporting of child health remains primarily unknown. OBJECTIVES: To examine relationships between parents' reporting of their own health and illness with the reporting of their children's health and illness. METHOD: We surveyed parents of a representative population-based sample of children aged 5 to 18 years. One parent of each child completed a written questionnaire including the Child Health Questionnaire, a subjective measure of functional health and well-being, and an assessment of self-reported parental health and illness. Logistic regression models were used to examine relationships between parent and child health and illness. MAIN RESULTS: 5340 parents responded (86% mothers, 14% fathers). After adjusting for confounding effects, parents self-reporting poor health had increased odds of reporting their children with poor health (odds ratio: 7.5), although the effect was modified by parent gender. There were increased odds of mothers with self-reporting poor global health reporting their children with poor global health and illness (odds ratio: 9.0 and 2.5, respectively) that were not observed for fathers. CONCLUSIONS: A mother's self-reported health is strongly associated with her reporting of her child's health; this was not observed for fathers. These results suggest that parental gender should be considered as a mediating factor in the reporting of child health.

Adolescent↗
PubMed2000

A randomized trial comparing transurethral resection of the prostate, laser therapy and conservative treatment of men with symptoms associated with benign prostatic enlargement: The CLasP study.

PURPOSE: We evaluated the effectiveness of a new technology (noncontact laser therapy) versus that of standard surgery (transurethral prostatic resection) and conservative management for lower urinary tract symptoms associated with benign prostatic enlargement. MATERIALS AND METHODS: Men with uncomplicated lower urinary tract symptoms, that is no acute or chronic urinary retention, were randomized to receive laser therapy with a noncontact, side firing neodymium:YAG probe, standard transurethral prostatic resection or conservative management, including monitoring without active intervention, in a large multicenter pragmatic randomized controlled trial called the CLasP study. Primary outcomes were International Prostate Symptom Score (I-PSS), maximum urinary flow rate, a composite measure of success based on I-PSS and maximum urinary flow rate categories, I-PSS quality of life score and post-void residual urine volume. Secondary outcomes included treatment failure, hospital stay and major complications. Followup was 7.5 months after randomization. Intent to treat analysis was done using analysis of covariance, proportional odds models and the Newman-Keuls multiple comparisons procedure. RESULTS: Of symptomatic patients 117, 117 and 106 were randomized to receive laser therapy, transurethral prostatic resection and conservative management, respectively. Baseline characteristics were similar. All primary outcomes indicated that transurethral prostatic resection and laser therapy were superior to conservative management, and resection was superior to laser therapy. As measured by combined improved symptoms and maximum urinary flow, a successful outcome was achieved in 81%, 67% and 15% of men who underwent transurethral prostatic resection, laser therapy and conservative management, respectively. Hospital stay was significantly shorter and complications fewer for laser therapy than for resection but catheters were in place significantly longer. Men treated conservatively did not have deterioration or treatment failure. CONCLUSIONS: Laser therapy and transurethral prostatic resection are effective for decreasing lower urinary tract symptoms and post-void residual urine volume as well as improving quality of life and maximum urinary flow in the short term in men presenting with moderate to severe symptoms. Transurethral prostatic resection is superior to laser therapy in terms of effectiveness but some patients may elect laser therapy due to the shorter hospital stay and lower risk of complications. Conservative management may be acceptable and safe in men with lower urinary tract symptoms since we observed no marked deterioration in the short term.

Aged↗
PubMed1999

Mortality among recent purchasers of handguns.

BACKGROUND: There continues to be considerable controversy over whether ownership of a handgun increases or decreases the risk of violent death. METHODS: We conducted a population-based cohort study to compare mortality among 238,292 persons who purchased a handgun in California in 1991 with that in the general adult population of the state. The observation period began with the date of handgun purchase (15 days after the purchase application) and ended on December 31, 1996. The standardized mortality ratio (the ratio of the number of deaths among handgun purchasers to the number expected on the basis of age- and sex-specific rates among adults in California) was the principal outcome measure. RESULTS: In the first year after the purchase of a handgun, suicide was the leading cause of death among handgun purchasers, accounting for 24.5 percent of all deaths and 51.9 percent of deaths among women 21 to 44 years old. The increased risk of suicide by any method among handgun purchasers (standardized mortality ratio, 4.31) was attributable entirely to an excess risk of suicide with a firearm (standardized mortality ratio, 7.12). In the first week after the purchase of a handgun, the rate of suicide by means of firearms among purchasers (644 per 100,000 person-years) was 57 times as high as the adjusted rate in the general population. Mortality from all causes during the first year after the purchase of a handgun was greater than expected for women (standardized mortality ratio, 1.09), and the entire increase was attributable to the excess number of suicides by means of a firearm. As compared with the general population, handgun purchasers remained at increased risk for suicide by firearm over the study period of up to six years, and the excess risk among women in this cohort (standardized mortality ratio, 15.50) remained greater than that among men (standardized mortality ratio, 3.23). The risk of death by homicide with a firearm was elevated among women (standardized mortality ratio at one year, 2.20; at six years, 2.01) but low among men (standardized mortality ratio at one year, 0.84; at six years, 0.79). CONCLUSIONS: The purchase of a handgun is associated with a substantial increase in the risk of suicide by firearm and by any method; the increase in the risk of suicide by firearm is apparent within a week after the purchase of a handgun. The magnitude of the increase and the relation between handgun purchase and the risk of death by homicide differ between men and women.

Adult↗
PubMed1999

Human 76p: A new member of the gamma-tubulin-associated protein family.

The role of the centrosomes in microtubule nucleation remains largely unknown at the molecular level. gamma-Tubulin and the two associated proteins h103p (hGCP2) and h104p (hGCP3) are essential. These proteins are also present in soluble complexes containing additional polypeptides. Partial sequencing of a 76- kD polypeptide band from these complexes allowed the isolation of a cDNA encoding for a new protein (h76p = hGCP4) expressed ubiquitously in mammalian tissues. Orthologues of h76p have been characterized in Drosophila and in the higher plant Medicago. Several pieces of evidence indicate that h76p is involved in microtubule nucleation. (1) h76p is localized at the centrosome as demonstrated by immunofluorescence. (2) h76p and gamma-tubulin are associated in the gamma-tubulin complexes. (3) gamma-tubulin complexes containing h76p bind to microtubules. (4) h76p is recruited to the spindle poles and to Xenopus sperm basal bodies. (5) h76p is necessary for aster nucleation by sperm basal bodies and recombinant h76p partially replaces endogenous 76p in oocyte extracts. Surprisingly, h76p shares partial sequence identity with human centrosomal proteins h103p and h104p, suggesting a common protein core. Hence, human gamma-tubulin appears associated with at least three evolutionary related centrosomal proteins, raising new questions about their functions at the molecular level.

Amino Acid Sequence↗
PubMed1999

Inhibition of tumor growth correlates with the expression level of a human angiostatin transgene in transfected B16F10 melanoma cells.

Although the therapeutic value of angiostatin, a proteolytic fragment of plasminogen, has been recognized for the treatment of cancer, the production of bioactive angiostatin remains a difficult task. Here we report that expression of a cDNA encoding a secreted, four-kringle human angiostatin inhibited tumor growth of B16F10 melanoma cells in mice but did not suppress tumor cell growth in culture. After transfection and selection, stable expression of the angiostatin cDNA was demonstrated in several B16F10 clones by quantitative mRNA analysis using the Taqman method. Cells that expressed angiostatin at either a low, medium, or high level were injected into C57BL/6 mice. s.c. Growth of B16F10 tumors was diminished by the angiostatin transgene, and the inhibition was directly proportional to the expression level of angiostatin in the transfected cells. However, suppression of s.c. tumor growth was transient, and eventually, tumors emerged with a strongly decreased expression of the transgene. Angiostatin expression also reduced lung metastasis from i.v.-injected B16F10 cells. Our data indicate that a cDNA encoding bioactive human angiostatin is potentially useful for gene therapy of human cancers, but the delivery of the transgene may require repeated dosing to achieve sustained dormancy of primary tumors and cancer metastases.

Angiostatins↗
PubMed1999

Identification of a Wnt-responsive signal transduction pathway in primary endothelial cells.

The beta-catenin signal transduction pathway, which can be activated by secreted Wnt proteins, plays a key role in normal embryonic development and in malignant transformation of the mammary gland and colon. Here we demonstrate, for the first time, that Wnt and beta-catenin signaling also function in cells of the vasculature. RT-PCR analysis showed that primary endothelial and smooth muscle cell cultures, of both mouse and human origin, express members of the Wnt and Wnt receptor (Frizzled) gene families. Transfection of an expression vector for Wnt-1 into primary endothelial cells increased both the free pool of beta-catenin and the transcription from a Lef/tcf-dependent reporter gene construct. Expression of Wnt-1, but not Wnt-5a, also stimulated proliferation of primary endothelial cell cultures. These data show that Wnt and Frizzled proteins can regulate signal transduction, via beta-catenin, in endothelial cells. These findings suggest that Wnt signaling may feature in normal differentiation of the vasculature as well as in pathological settings where endothelial and smooth muscle proliferation is disturbed.

Animals↗
PubMed1999

Differential in vitro association of vinca alkaloid-induced tubulin spiral filaments into aggregated spirals.

Vinblastine, vincristine, vindesine, and vinorelbine, the four vinca alkaloids used in cancer therapy, differ in their antitumoral spectra and toxicities, but not in their inhibitory effects on microtubule assembly in vitro. At higher drug concentrations, vinca alkaloids induce the assembly of spiral filaments of tubulin, which, in turn, can interact laterally and form paracrystals. Using methods that distinguish spiral filaments and paracrystals (aggregated spirals), we found that spiral filament formation was largely independent of the incubation temperature, of the alkaloid used, and of the presence or absence of microtubule-associated proteins (MAPs). In contrast, the formation of aggregated spirals was markedly dependent on the alkaloid used, on the incubation temperature, and on the absence or presence of MAPs. Aggregated spirals failed to assemble in the presence of high concentrations of MAP-1A or MAP-1B, whereas they assembled readily with tau and MAP-2. Differences in patterns of turbidity development using pure tubulin allowed the classification of thirteen cytotoxic vinca alkaloids into five distinct groups, with centrifugal recovery of aggregated spirals in close agreement with the various turbidity patterns. With microtubule protein, i.e. tubulin preparations containing MAPs, only four groups were defined by turbidity patterns, and centrifugal protein recovery was more divergent. Vinblastine, vincristine, vindesine, and vinorelbine fell into distinct groups under both reaction conditions, and thus they appear to have qualitatively distinguishable in vitro interactions with tubulin. These differential effects on spiral filament and aggregated spiral assembly revealed that the four drugs induce different constraints on the tubulin molecule.

Animals↗
PubMed1999

The mammalian interphase centrosome: two independent units maintained together by the dynamics of the microtubule cytoskeleton.

In mammalian cells the centrosome or diplosome is defined by the two parental centrioles observed in electron microscopy and by the pericentriolar material immunostained with several antibodies directed against various centrosomal proteins (gamma-tubulin, pericentrin, centrin and centractin). Partial destabilization of the microtubule cytoskeleton by microtubule-disassembling substances induced a splitting and a slow migration of the two diplosome units to opposite nuclear sides during most of the interphase in several mammalian cell lines. These units relocated close together following drug removal, while microtubule stabilization by nM taxol concentrations inhibited this process. Cytochalasin slowed down diplosome splitting but did not affect its relocation after colcemid washing. These results account for the apparently opposite effects induced by microtubule poisons on centriole separation. Moreover, they provide new information concerning the centrosome cycle and stability. First, the centrosome is formed by two units, distinguished only by the number of attached stable microtubules, but not by pericentrin, gamma-tubulin, centrin and centractin and their potency to nucleate microtubules. Second, the centrosomal units are independent during most of the interphase. Third, according to the cell type, these centrosomal units are localized in close proximity because they are either linked or maintained close together by the normal dynamics of the microtubule cytoskeleton. Finally, the relocalization of the centrosomal units with their centrioles in cells possessing one or two centrosomes suggests that their relative position results from the overall tensional forces involving at least partially the microtubule arrays nucleated by each of these entities.

Animals↗
PubMed1999

D-dimer for the exclusion of venous thromboembolism: comparison of a new automated latex particle immunoassay (MDA D-dimer) with an established enzyme-linked fluorescent assay (VIDAS D-dimer).

The use of D-dimer tests to exclude venous thromboembolism is an important advance in clinical practice and also has economic benefits. Ideally the test should be objective and a test that could be run on the routine coagulometer would obviate the need for additional investment in alternative hardware. A new automated latex particle immunoassay (MDA D-dimer) that can be run on a routine coagulometer was compared with a well established enzyme linked fluorescent assay (VIDAS D-dimer) on the basis of their ability to exclude venous thromboembolism. The assays were compared in 49 patients presenting to the emergency department with clinically suspected deep vein thrombosis or pulmonary embolism. After objective diagnostic imaging, 20 patients were confirmed to have venous thromboembolism. There was strong agreement between the assays in individual patients. Using a cut-off of 500 micrograms/l, both tests had a sensitivity of 100% and therefore a negative predictive value of 100%, however the MDA test would have spared more patients (20% vs. 12%) from further testing if a negative D-dimer was used to rule-out the diagnosis. It was concluded that a rapid, objective latex D-dimer test run on a routine coagulometer (MDA D-dimer) can be used to exclude the diagnosis of venous thromboembolism.

Enzyme-Linked Immunosorbent Assay↗