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D J Moore

Publications and source records attributed to D J Moore.

At least 37 records · Page 2Linked to original sources
PubMed2001

Activation and association of the Tec tyrosine kinase with the human prolactin receptor: mapping of a Tec/Vav1-receptor binding site.

Stimulation of the PRL receptor (PRLr) results in the activation of the guanine nucleotide exchange factor (GEF) p95Vav1 with corresponding alterations in cytoarchitecture and cell motility. To better understand the mechanisms involved in the regulation of Vav1 activity, the role of the tyrosine kinase p70Tec was examined. Coimmunoprecipitation and in vitro kinase assays revealed that ligand stimulation of the PRLr resulted in the rapid activation of Tec and its concomitant association with the PRLR: When coexpressed in COS-1 cells, both Vav1 and Tec were found to associate with the PRLr in the presence of ligand. In the absence of receptor, a constitutive complex between Vav1 and Tec was noted. Both Vav1 and Tec, however, were capable of independent engagement of a bipartite intracellular domain of the PRLR: Deletion mapping studies confined this interaction to residues 323 to 527 of the intracellular domain of the PRLR: Furthermore, Tec enhanced the GEF activity of Vav1 as evidenced by an increase in GTP-bound Rac1. These data would suggest a pivotal function for the formation of a Tec/Vav1/PRLr complex during PRL-driven signal transduction, given the role of Vav1 in the control of cell proliferation and the regulation of Rho family-mediated cytoskeletal alterations.

3T3 Cells↗
PubMed2001

The effect of age on the macromolecular permeability of human Bruch's membrane.

PURPOSE: To determine whether age-related changes in Bruch's membrane affect its permeability to macromolecules. Such changes have been postulated to underlie some pathologic manifestations of age-related macular degeneration. METHODS: Bruch's membrane preparations were isolated from the macular region of donated human eyes of differing age and mounted in a modified Ussing chamber. Permeability to macromolecules was assessed by simultaneously placing a physiological concentration of serum proteins adjacent to the choroidal margin of the membrane preparation and a saline solution adjacent to the retinal pigment epithelial basement membrane. After 24 hours, the protein content of the saline solution was measured by standard assay and permeability calculated as the quantity of protein traversing the membrane preparation per unit area. The spectrum of proteins able to cross the membrane was assessed by subjecting the diffusate proteins to electrophoretic separation and the resultant gel to scanning densitometry. RESULTS: The permeability of Bruch's membrane to serum proteins decreased 10-fold from the first to the ninth decade of life, and on regression analysis this decline exhibited a linear relationship with donor age (P < 0.0005). Membrane preparations from young donors were permeable to proteins with a molecular weight in excess of 200 kDa, but with increasing age, the membrane progressively impeded the passage of high-molecular-weight entities. Even so, elderly membranes were still permeable to macromolecules with molecular weights in excess of 100 kDa. Results from the oldest preparation studied suggest that by the ninth decade, the membrane may selectively impede the flux of specific proteins, based on a criterion other than molecular weight. CONCLUSIONS: The results imply that, with increasing age, the capacity of Bruch's membrane to facilitate macromolecular exchange between the choroidal and the retinal pigment epithelial compartments is reduced.

Adolescent↗
PubMed2000

Mutation of a BRCT domain selectively disrupts DNA single-strand break repair in noncycling Chinese hamster ovary cells.

The DNA single-strand break repair protein XRCC1 contains a BRCT domain that binds and stabilizes intracellular DNA ligase III protein. We recently demonstrated that this domain is largely dispensable for single-strand break repair and cellular resistance to DNA base damage in cycling cells. Here, we report that the BRCT domain is required for single-strand break repair in noncycling cells. Mutations that disrupt the BRCT domain and prevent DNA ligase III interaction abolished XRCC1-dependent repair in serum-starved Chinese hamster ovary cells, and reentry into cell cycle induced by readdition of serum restored repair. Elevating DNA ligase III levels in XRCC1 mutant cells using proteosome inhibitors or by expressing XRCC1 protein in which the BRCT domain is disrupted but can still bind DNA ligase III failed to restore repair in noncycling cells. The requirement for the BRCT domain for DNA strand break repair is thus for more than simply binding and stabilizing DNA ligase III. These data provide evidence in support of a selective role for a DNA repair protein or protein domain in noncycling cells. We propose that the XRCC1 C-terminal BRCT domain may be important for genetic stability in postmitotic cells in vivo.

Animals↗
PubMed2000

Non-alcoholic steatohepatitis in children and adolescents.

We describe 17 children with non-alcoholic steatohepatitis. All had elevated levels of serum liver enzymes and 16 were morbidly obese. Liver biopsy showed variable steatosis and fibrosis in nine patients. At follow-up, 12 of 14 patients had persistent morbid obesity and 11 had elevated liver enzyme levels.

Adolescent↗
PubMed2000

Impaired CD4 T cell activation due to reliance upon B cell-mediated costimulation in nonobese diabetic (NOD) mice.

Diabetes in nonobese diabetic (NOD) mice results from the activation of I-A(g7)-restricted, islet-reactive T cells. This study delineates several characteristics of NOD CD4 T cell activation, which, independent of I-A(g7), are likely to promote a dysregulated state of peripheral T cell tolerance. NOD CD4 T cell activation was found to be resistant to antigenic stimulation via the TCR complex, using the progression of cell division as a measure. The extent of NOD CD4 T cell division was highly sensitive to changes in Ag ligand density. Moreover, even upon maximal TCR complex-mediated stimulation, NOD CD4 T cell division prematurely terminated. Maximally stimulated NOD CD4 T cells failed to achieve the threshold number of division cycles required for optimal susceptibility to activation-induced death, a critical mechanism for the regulation of peripheral T cell tolerance. Importantly, these aberrant activation characteristics were not T cell-intrinsic but resulted from reliance on B cell costimulatory function in NOD mice. Costimulation delivered by nonautoimmune strain APCs normalized NOD CD4 T cell division and the extent of activation-induced death. Thus, by disrupting the progression of CD4 T cell division, polarization of APC costimulatory function to the B cell compartment could allow the persistence and activation of diabetogenic cells in NOD mice.

Animals↗
PubMed2000

Fourier transform infrared spectroscopy and differential scanning calorimetry studies of fatty acid homogeneous ceramide 2.

Ceramides provide a major component of the barrier function of skin. An understanding of barrier organization requires a detailed characterization of ceramide phase behavior and molecular interactions. Toward this end, Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) studies of ceramide 2 analogues (non-hydroxylated fatty acid N-acyl sphingosines) of specific chain lengths (C(14), C(16), C(18), C(20)) are presented. In addition, the molecular interactions of the individual chains in each molecule are elucidated through thermotropic FTIR studies of derivatives possessing perdeuterated fatty acid chains. DSC data showed a much smaller chain length variation (for the C(16), C(18), C(20) derivatives) in the main order-disorder transition temperature (approx. 93+/-1 degrees C) than is observed in the corresponding series of phosphatidylcholines, consistent with minimal ceramide hydration. The temperature dependence of the methylene stretching and scissoring modes revealed a solid-solid phase transition at 20-25 degrees C below the main order-disorder transition accompanied by chain packing alterations from orthorhombic-->hexagonal subcells. The chain packing transition was accompanied by enhanced penetration of water into the polar region. This was deduced from the temperature dependence of the amide I and II modes, which provide direct evidence for H-->D exchange. The CD(2) scissoring mode splitting of the deuterated fatty acid constituent of the C(16), C(18), C(20) chains revealed preferential segregation of microdomains (3-5 chains) of this species within the orthorhombic phase. In contrast, the sphingosine base chains appeared to be sufficiently separated so as to inhibit interchain vibrational coupling between them. FTIR spectroscopy provides a convenient means for characterizing domain formation, chain packing, and hydration sites of these phases, which are highly ordered under physiological conditions.

Calorimetry, Differential Scanning↗
PubMed2000

Analysis of the breath hydrogen test for carbohydrate malabsorption: validation of a pocket-sized breath test analyser.

OBJECTIVE: To assess the validity and clinical application of a hand-held breath hydrogen (H2) analyzer (BreatH2, Europa Scientific, Crewe, UK). METHODOLOGY: Breath samples of patients referred to the Gastroenterology Unit, Women's and Children's Hospital, North Adelaide, South Australia, for confirmation of the diagnosis of carbohydrate malabsorption were analysed with the Quintron microlyzer (Quintron Instrument Co., Milwaukee, USA) and the BreatH2 analyser, using the Quintron microlyzer as the gold standard. RESULTS: Twenty-nine breath H2 tests (BHT) were performed in 29 patients aged 2 months to 61 years. The sensitivity and specificity of the BreatH2 analyser in detecting a positive BHT using the Quintron microlyser as the gold standard were 0.90 and 0.95 with positive and negative predictive values of 0.90 and 0.95, respectively. There was one false positive and one false negative reading. Bland-Altman plots showed a high degree of agreement between the values obtained with two different methods. CONCLUSIONS: The diagnosis of carbohydrate malabsorption, using a portable breath H2 analyser (BreatH2), achieved an acceptable degree of sensitivity and specificity, enabling it to be used where no alternative is available.

Adolescent↗
PubMed2000

Insights into the molecular organization of lipids in the skin barrier from infrared spectroscopy studies of stratum corneum lipid models.

In order to gain some insight into the molecular organization of lipids in the skin barrier we used Fourier transform infrared (FTIR) spectroscopy to investigate models of the stratum corneum (SC) containing deuterated hexadecanoic acid, cholesterol, and ceramide 2 or ceramide 5. In both models there is clear evidence of separate conformationally ordered domains of ceramide and fatty acids. In addition, these chains are packed in orthorhombic subcells at physiological temperatures. The ceramide headgroup behavior indicates distinct hydrogen bonding patterns between the ceramide 2 and ceramide 5 models. In the ceramide 2 model the amide I mode is split into two components suggesting strong transverse intermolecular hydrogen bonding between headgroups. In contrast, no amide splitting is observed for ceramide 5 although the amide frequencies are indicative of strong hydrogen bonding. These observations on the molecular organization of SC lipids are discussed in terms of skin barrier function.

Amides↗
PubMed2000

Cricket fast bowling performance and technique and the influence of selected physical factors during an 8-over spell.

The aims of this study were to determine the influence of an 8-over spell on cricket fast bowling technique and performance (speed and accuracy), and to establish the relationship of selected physical capacities with technique and performance during an 8-over spell. Fourteen first-grade fast bowlers with a mean age of 23 years participated in the study. Physical capacities assessed were abdominal strength, trunk stability, selected girth and skinfold measures. During the delivery stride, bowlers were filmed from an overhead and lateral perspective (50 Hz) to obtain two-dimensional data for transverse plane shoulder alignment and sagittal plane knee joint angle respectively. Ball speed was measured by a radar gun and accuracy by the impact point of each delivery on a zoned scoring target at the batter's stumps. Shoulder counter-rotation did not change significantly between overs 2 and 8 for all bowlers, but was significantly related to a more front-on shoulder orientation at back foot impact. When the front-on fast bowlers (n = 5) were isolated for analysis, shoulder counter-rotation increased significantly between overs 2 and 8. Ball speed remained constant while accuracy showed some non-significant variation during the spell. Shoulder counter-rotation was significantly related to accuracy scores during the second half of the 8-over spell. Chest girth and composition and body composition were significantly related to ball release speed at various times during the spell.

Adult↗
PubMed2000

A cell cycle-specific requirement for the XRCC1 BRCT II domain during mammalian DNA strand break repair.

XRCC1 protein is essential for viability in mammals and is required for efficient DNA single-strand break repair and genetic stability following DNA base damage. We report here that XRCC1-dependent strand break repair in G(1) phase of the cell cycle is abolished by mutations created within the XRCC1 BRCT domain that interact with DNA ligase III. In contrast, XRCC1-dependent DNA strand break repair in S phase is largely unaffected by these mutations. These data describe a cell cycle-specific role for a BRCT domain, and we conclude that the XRCC1-DNA ligase III complex is required for DNA strand break repair in G(1) phase of the cell cycle but is dispensable for this process in S phase. The S-phase DNA repair process can remove both strand breaks induced in S phase and those that persist from G(1) and can in part compensate for lack of repair in G(1). This process correlates with the appearance of XRCC1 nuclear foci that colocalize with Rad51 and may thus function in concert with homologous recombination.

Amino Acid Sequence↗
PubMed2000

Late presentation of upper airway obstruction in Pierre Robin sequence.

A retrospective review was carried out of 11 consecutive patients with the Pierre Robin sequence referred to a tertiary paediatric referral centre over a five year period from 1993 to 1998. Ten patients were diagnosed with significant upper airway obstruction; seven of these presented late at between 24 and 51 days of age. Failure to thrive occurred in six of these seven infants at the time of presentation, and was a strong indicator of the severity of upper airway obstruction. Growth normalised on treatment of the upper airway obstruction with nasopharyngeal tube placement. All children had been reviewed by either an experienced general paediatrician or a neonatologist in the first week of life, suggesting that clinical signs alone are insufficient to alert the physician to the degree of upper airway obstruction or that obstruction developed gradually after discharge home. The use of polysomnography greatly improved the diagnostic accuracy in assessing the severity of upper airway obstruction and monitoring the response to treatment. This report highlights the prevalence of late presentation of upper airway obstruction in the Pierre Robin sequence and emphasises the need for close prospective respiratory monitoring in this condition. Objective measures such as polysomnography should be used, as clinical signs alone may be an inadequate guide to the degree of upper airway obstruction.

Age of Onset↗
PubMed2000

Suprarenal mycotic aneurysm exclusion using a stent with a partial autologous covering.

PURPOSE: To report a combined endovascular and open technique to manage a suprarenal mycotic aortic aneurysm using a stent-graft partially covered with a section of autologous artery. METHODS AND RESULTS: A 50-year-old was hospitalized for staphylococcal septicemia and severe back pain. A previously diagnosed 3-cm abdominal aortic aneurysm was found to have expanded 2 cm in 3 weeks. Aortography documented some periaortic thickening and 2 mycotic aneurysms, one posterior at the level of the superior mesenteric artery and the second at the aortic bifurcation. After intensive antibiotic therapy, an endovascular approach to exclude the suprarenal mycotic aneurysm was undertaken in tandem with surgical excision of the infrarenal aneurysm. The harvested right common iliac artery was used to partially cover a Palmaz stent, which was deployed under direct vision just above the renal artery ostia so that the covered portion of the stent excluded the aneurysm. A right axillofemoral bypass with a femorofemoral bypass completed the revascularization. Postoperatively, the patient developed renal failure, ischemic colitis necessitating a left hemicolectomy, and paraplegia. Although the patient is paralyzed, the aneurysm remains excluded with patent visceral vessels at 12 months following surgery. No organisms were grown from excised aortic tissue, and no signs of recurrent infection have been seen. CONCLUSIONS: Stent-graft repair may be able to lessen the invasiveness and reduce the morbidity associated with treatment of mycotic aortic aneurysms.

Aneurysm, Infected↗
PubMed2000

Endovascular management of rare sciatic artery aneurysm.

PURPOSE: To present a rare case of complete persistent sciatic artery aneurysm successfully treated by coil embolization and to suggest a new classification for this anomaly that encompasses both clinical and pathological factors. METHODS AND RESULTS: A 77-year-old female presented with sudden onset of sharp, throbbing left thigh and foot pain. A nontender 10.0- x 7.0-cm pulsatile mass was found over the inferolateral aspect of the left buttock on examination in the right lateral decubitus position. Angiography demonstrated a 6.9-cm sciatic artery aneurysm with the distal sciatic artery completely thrombosed. Before planned bypass grafting, the aneurysm and distal segment of the internal iliac artery were successfully embolized with coils through a left percutaneous approach. The patient's symptoms resolved with no deterioration in limb perfusion, and further revascularization was unnecessary. Postembolization imaging showed complete occlusion of the aneurysm, which has continued for 19 months. CONCLUSIONS: The application of endovascular techniques and surgical revascularization procedures provides numerous management options for the treatment of an aneurysmal persistent sciatic artery. This case demonstrates that clinical evaluation between staged procedures may obviate the need for further intervention.

Aged↗
PubMed2000

Regulation of the CYP3A4 gene by hydrocortisone and xenobiotics: role of the glucocorticoid and pregnane X receptors.

The molecular mechanisms of regulation of the CYP3A4 gene have been examined in an in vitro reporter gene system, containing -1 kb of the CYP3A4 promoter, in a HepG2 cell line. This system allows for the separate and combined transfection of expression plasmids encoding the human glucocorticoid receptor (hGR) and the human pregnane X receptor (hPXR), and, therefore, the opportunity to assess the role of these receptors in the induction process. Hydrocortisone produces a dose-dependent increase in CYP3A4 activation, a response that is increased in the presence of either receptor. Moreover, transfection of the hPXR decreased the EC(50) for hydrocortisone-dependent induction by a factor of 3.3, a response that was not changed by simultaneous cotransfection of the hGR. In addition, the hydrocortisone dose-response curve falls within the physiological blood level concentration of this steroid, implicating a regulatory role for hydrocortisone in the basal level of CYP3A4 expression. Although the responses to dexamethasone and rifampicin were both increased by both receptors, dexamethasone activation of CYP3A4 was similar for both the hGR and the hPXR, whereas rifampicin-dependent activation favored the hPXR. We conclude that regulation of the CYP3A4 gene is receptor-dependent and that hydrocortisone may function as a regulator of basal expression via the hPXR and the hGR. The implications of this latter conclusion for possible regulatory interactions between hydrocortisone and xenobiotic inducers remain to be clarified.

Alkaline Phosphatase↗
PubMed2000

Tibial and peroneal artery bypasses using polytetrafluoroethylene (PTFE) with an interposition vein cuff.

UNLABELLED: The combined results of femoro-distal bypasses using prosthetic material with vein cuffs from two separate vascular units is presented. METHOD: Over the last five years, 89 infrainguinal bypasses using polytetrafluoroethylene (PTFE) with a distal interposition vein cuff to a tibial artery have been performed in two centres. All operations were for critical limb ischaemia. The mean age was 72 years (47-90), there were 46 males and 43 females, 27 of whom were diabetic. Twenty-eight patients had a history of angina and/or previous myocardial infarct. The median follow-up was 12 months (0-68 months). RESULTS: During the follow-up period there were 28 deaths, 35 major limb amputations and 44 graft failures. The graft patency rates at 12 and 24 months were 50 and 32%, and limb salvage rates were 53 and 44%, respectively. The patient survival rates were 66 and 61%, respectively. CONCLUSION: The authors believe that the likely improvement in pain free quality of life the patient may enjoy with a successful bypass shifts the balance in some individuals towards bypass surgery using PTFE with a vein cuff to a tibial artery when such an option is possible.

Aged↗
PubMed1999

Contribution of the innate immune system to autoimmune diabetes: a role for the CR1/CR2 complement receptors.

B lymphocytes are required for diabetogenesis in nonobese diabetic (NOD) mice. The complement component of the innate immune system regulates B cell activation and tolerance through complement receptors CR1/CR2. Thus, it is important to assess the contribution of complement receptors to autoimmune diabetes in NOD mice. Examination of the lymphoid compartments of NOD mice revealed striking expansion of a splenic B cell subset with high cell surface expression of CR1/CR2. This subset of B cells exhibited an enhanced C3 binding ability. Importantly, long-term in vivo blockade of C3 binding to CR1/CR2 prevented the emergence of the CR1/CR2(hi) B cells and afforded resistance to autoimmune diabetes in NOD mice. These findings implicate complement as an important regulatory element in controlling the T cell-mediated attack on islet beta cells of NOD mice.

Animals↗
PubMed1999

Some relationships between membrane phospholipid domains, conformational order, and cell shape in intact human erythrocytes.

A novel method developed in this laboratory [D.J. Moore et al., Biochemistry 35 (1996) 229-235; D.J. Moore et al., Biochemistry 36 (1997) 660-664] to study the conformational order and the propensity for domain formation of specific phospholipids in intact human erythrocytes is extended to two additional species. Acyl chain perdeuterated 1,2-dilauroylphosphatidylethanolamine (diC12PE-d46) was incorporated preferentially (in separate experiments) into the inner leaflet of stomatocytic erythrocytes and into the outer leaflet of echinocytic erythrocytes, while acyl chain perdeuterated 1,2-dipentadecanoylphosphatidylcholine (diC15PC-d58) was incorporated into the outer leaflet of echinocytic erythrocytes. The conformational order and phase behavior of the incorporated molecules were monitored through FT-IR studies of the temperature dependence of the CD2 stretching vibrations. For both diC12PE-d46 and diC15PC-d58, the gel-->liquid crystal phase transition persisted when these lipids were located in the outer leaflet of echinocytic cells, a result indicative of the persistence of phospholipid domains. In each case, the transition widths were broadened compared to the pure lipids, suggestive of either small domains or the presence of additional molecular components within the domains. The conformational order of diC12PE-d46 differed markedly depending on its location and the morphology of the cells. When located predominantly in the inner membrane of stomatocytes, the phase transition of this species was abolished and the conformational order compared with pure lipid vesicles at the same temperature was much lower. The current results along with our previous studies provide a sufficient experimental basis to deduce some general principles of phospholipid conformational order and organization in both normal and shape-altered erythrocytes.

Cell Size↗