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D M Burns

Publications and source records attributed to D M Burns.

At least 37 records · Page 2Linked to original sources
PubMed1999

Breast cancer cell-associated endopeptidase EC 24.11 modulates proliferative response to bombesin.

We have investigated the production, growth and inactivation of gastrin-releasing peptide (GRP)-like peptides in human breast cancer cell lines. Radioimmunoassay detected GRP-like immunoreactivity (GRP-LI) in T47D breast cancer cells but not in the conditioned medium, indicating rapid clearance. No GRP-LI was found in the ZR-75-1 or MDA-MB-436 cells or their conditioned medium. High-performance liquid chromatography (HPLC) analysis of the GRP-LI in the T47D cells revealed a major peak, which co-eluted with GRP(18-27), and a minor more hydrophilic peak. In vitro stimulation of T47D cell growth by bombesin (BN) was enhanced to 138% of control levels (bombesin alone) by the addition of the selective endopeptidase EC 3.4.24.11 inhibitor phosphoramidon (0.1 ng ml(-1)). Fluorogenic analysis using whole cells confirmed low levels of this phosphoramidon-sensitive enzyme on the T47D cells. This enzyme, previously unreported in human breast cancer cells, significantly modulates both T47D growth and its response to BN-induced growth.

Bombesin↗
PubMed1999

Calcitonin gene-related peptide acts as a mitogen for human Gin-1 gingival fibroblasts by activating the MAP kinase signalling pathway.

In many peripheral tissues, calcitonin gene-related peptide (CGRP) is released from peptidergic sensory nerve fibres and acts like a growth factor during tissue development and regeneration. However, the ability of CGRP to influence gingival tissue has not been studied. To address this question, we have now examined the effects of CGRP on the proliferation of human gingival fibroblasts (Gin-1) in vitro. Gin-1 cells have approximately 3100 specific CGRP-binding sites with a Kd of 38.6 pM on their surface. Treatment with CGRP (0.1-100 nM) significantly stimulated cell proliferation in a dose-dependent manner, with maximal effects at 1-10 nM CGRP after 2 d. As one early cellular response to CGRP, p44-MAPK protein (also known as the extracellular signal response kinase [ERK]) was tyrosine- and threonine-phosphorylated within 2 min, and this phosphorylation was sustained for at least 1 h. The dose-response curve of MAPK activation was very similar to that observed for CGRP's stimulation of cell proliferation. In addition, CGRP's activation of MAPK stimulated its ability to phosphorylate the Elk-1 transcription factor. When cells were pretreated with PD98059, a selective inhibitor of MAPK kinase (also known as MEK), CGRP not only failed to induce phosphorylation of MAPK but also failed to stimulate Gin-1 cell proliferation. Our present data indicate that CGRP rapidly activates the MAPK signalling pathway, an effect which consequently stimulates the proliferation of gingival fibroblasts. Our data demonstrate specific cellular responses to CGRP by gingival fibroblasts and support the possibility that CGRP acts as a targeted local factor in the regulation of development, generation and/or regeneration of gingival tissues.

Analysis of Variance↗
PubMed1998

Up-regulation of inducible nitric oxide (NO) synthase and NO production in HL-60 cells stimulated to differentiate by phorbol 12-myristate 13-acetate plus 1,25-dihydroxyvitamin D3 is not obtained with dimethylsulfoxide plus 1,25-dihydroxyvitamin D3.

In previous studies we found that the calciotropic hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] augments the action of either prostaglandin E1 (PGE1) or NaF to induce differentiation of human promyelocytic HL-60 cells, a process that features increased generation of nitric oxide (NO) via up-regulation of inducible nitric oxide synthase (iNOS). We have now examined the short-term interaction of 1,25(OH)2D3 with phorbol 12-myristate 13-acetate (PMA) and dimethylsulfoxide (DMSO) in these cells. PMA (100 nM) alone generally up-regulated several classical indices of macrophagic differentiation and stimulated cellular production of interleukin (IL)-1alpha, IL-6, tumor-necrosis factor (TNF)-alpha, PGE2, and NO. Increased generation of NO primarily resulted from increased expression of cellular iNOS. When 1,25(OH)2D3 (10 nM) was added to PMA treatments, most PMA-induced changes, particularly its effects to up-regulate iNOS-dependent NO production and change cell morphology, were multiplicatively augmented. In contrast, DMSO (1.3%) alone, an inducer of granulocytic differentiation, increased cytokine production, but failed to stimulate NO production or induce iNOS. In contrast to its striking interaction with PMA, 1,25(OH)2D3 could not augment DMSO's differentiative effects. Changes in cellular cytokine production were eliminated as the driving force in HL-60 differentiation when specific neutralizing antibodies failed to produce any attenuation of iNOS up-regulation or of the shifts in cell morphology. However, indomethacin (30 microM) blocked the synergistic interaction between 1,25(OH)2D3 + PMA to shift cell morphology and stimulate NO production. Subsequently adding PGE2 (1 ng/ml) to indomethacin-treated cells restored the ability of 1, 25(OH)2D3 + PMA to interactively increase cellular NO production, but failed to fully replicate the strong shift in cell morphology typical of PMA + 1,25(OH)2D3 treatments. Our findings suggest that interaction between 1,25(OH)2D3 and PMA to induce macrophagic differentiation increases iNOS-dependent NO production by a mechanism involving a cyclooxygenase product(s), possibly PGE2.

Calcitriol↗
PubMed1998

Calcitonin gene-related peptide stimulates potassium efflux through adenosine triphosphate-sensitive potassium channels and produces membrane hyperpolarization in osteoblastic UMR106 cells.

In previous studies, we have shown that calcitonin gene-related peptide (CGRP) acutely inhibits 45Ca2+ uptake in osteoblastic UMR106 cells, and we have proposed that ATP-sensitive potassium (K(ATP)) channels are involved in mediating this action of CGRP. To directly test this proposed mechanism, we have now examined the effects of CGRP on both membrane potential (Em) and K+ mobilization in UMR106 cells, using specific fluorometric dye assays. CGRP (0.01-100 nM) induced membrane hyperpolarization in a dose-dependent manner, with a half maximal effect (ED50) at approximately 0.2 nM and a maximal effect at 100 nM. Both pinacidil (Pina; a K(ATP) channel opener) and forskolin (FSK) induced similar membrane hyperpolarization, but the actions of these three agents could be easily distinguished: both CGRP and Pina actions were well antagonized by glibenclamide (Glib; a selective K(ATP) channel blocker), whereas FSK action was strongly attenuated only by tetraethylammonium (a K(Ca) channel blocker) or compound H-89 (an inhibitor of cAMP-dependent protein kinases). Cells pretreated with Pina no longer responded to CGRP, but they could still respond to FSK; furthermore, pretreatment with FSK failed to block successive treatment with either CGRP or Pina. In parallel with observed changes in Em, CGRP (0.01-100 nM) decreased intracellular K+ concentrations ([K+]i) in a dose-dependent manner, with an ED50 identical to that obtained for alterations in Em. This action of CGRP was sensitive to Glib and had only slight sensitivity to tetraethylammonium; this CGRP effect was mimicked by Pina but not by FSK. Interestingly, CGRP significantly elicited changes in cell shape by a Glib-sensitive mechanism that included notable decreases in cross-sectional cytoplasmic area. These observations strongly support our proposal that CGRP primarily stimulates K+ efflux via activation of K(ATP) channels and thereby induces membrane hyperpolarization in UMR106 cells. Furthermore, our data also suggest that this cascade of initial cellular events may result in rapid changes in cell morphology and decreases in cellular area of the type that are thought to act as triggers for proliferation and/or differentiation in many cellular phenotypes.

Adenosine Triphosphate↗
PubMed1997

First chronic platelet glycoprotein IIb/IIIa integrin blockade. A randomized, placebo-controlled pilot study of xemilofiban in unstable angina with percutaneous coronary interventions.

BACKGROUND: Clinical studies have demonstrated the efficacy of intravenous administration of agents that block platelet glycoprotein IIb/IIIa receptors in the setting of percutaneous coronary revascularization. Although the optimal duration of treatment has not been determined, more prolonged receptor blockade has been associated with increased efficacy. Orally active glycoprotein IIb/IIIa receptor antagonists may be advantageous and required for chronic therapy. METHODS AND RESULTS: Thirty patients with unstable angina who were undergoing percutaneous coronary interventions were randomized to placebo or Xemilofiban 35 mg orally before and 20 to 25 mg TID for 30 days after angioplasty. Bleeding events, platelet aggregation, and pharmacokinetic and hematologic parameters were assessed during hospitalization and at 2 and 4 weeks after drug initiation. Xemilofiban produced a rapid, sustained, marked inhibition of platelet aggregation. ADP-induced platelet aggregation at 2 hours after the initial dose at 2 and 4 weeks was 15%, 8%, and 11% in the Xemilofiban group compared with 80%, 68%, and 69% in the placebo group. Among 20 patients randomized to Xemilofiban there was 1 death after emergency coronary bypass surgery complicated by severe bleeding diathesis, and 3 patients had major bleeding events. Patients on Xemilofiban for 30 days reported episodes of mild mucocutaneous bleeding. CONCLUSIONS: Xemilofiban, an orally active glycoprotein IIb/ IIIa receptor inhibitor, produced rapid, sustained, extensive inhibition of platelet aggregation for a period of up to 30 days. At the dose initially tested, however, acute major bleeding and mucocutaneous bleeding during chronic administration were encountered.

Adult↗
PubMed1996

Characteristics of NaF-induced differentiation of HL-60 cells.

Sodium fluoride (NaF) is known to stimulate osteoblastic bone formation, but little attention has been given to the possibility that NaF also affects bone resorption and the differentiation of osteoclastic progenitor cells. When human promyelocytic HL-60 cells were treated with NaF (0.5 mM, 0-4 days), cell proliferation was inhibited, and the addition of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) (10nM, 0-4 days) augmented this antiproliferative effect. NaF increased cellular reduction of nitroblue tetrazolium (NBT), and this effect was strongly augmented by 1,25(OH)2D3. In addition, NaF produced marked changes in cellular morphology, increased cellular adhesion to plastic, reduced the nuclear/cytoplasmic ratio, and increased cellular expression of chloroacetate esterase, but failed to alter cellular nonspecific esterase activity. Furthermore, NaF increased expression of CD11b and CD66b, and this stimulation was enhanced by adding 1,25(OH)2D3. The sum of these changes in classical promyelocytic cellular indices suggest: (1) that NaF stimulates the early stages of HL-60 differentiation toward a granulocyte-like cell and (2) that 1,25(OH)2D3 promotes these actions of NaF. Additional experiments aimed at further understanding the NaF-induced conversion of HL-60 cells identified further changes. NaF also increased cellular production of prostaglandin E2 (PGE2) and nitric oxide (NO) and induced expression of inducible nitric oxide synthase (iNOS); 1,25(OH)2D3 once again augmented these NaF-induced effects. Similarly, NaF stimulated the production of interleukin 1 alpha (IL-1 alpha), IL-6, and tumor necrosis factor-alpha, and 1,25(OH)2D3 again strongly enhanced these effects. Indomethacin completely blocked stimulation of NBT reduction, NO production, and iNOS expression induced by NaF plus 1,25(OH)2D3; adding exogenous PGE2 (0.1-10 ng/ml) to these indomethacin-blocked cultures dose-dependently restored NO production. These additional findings together with the observed slow onset (24-48 h) of NaF and 1,25(OH)2D3 interaction strongly suggest that 1,25(OH)2D3 acts as a cofactor with NaF primarily through interaction with an endogenous NaF-induced cyclo-oxygenase product(s), quite possibly PGE2 itself. Such a mechanism for NaF and 1,25(OH)2D3 interaction would be strongly analogous to the interaction we have recently demonstrated between 1,25(OH)2D3 and PGE1 on the differentiation of HL-60 cells.

Calcitriol↗
PubMed1996

Calcitonin gene-related peptide rapidly inhibits calcium uptake in osteoblastic cell lines via activation of adenosine triphosphate-sensitive potassium channels.

In certain neurons, alternative RNA processing generates calcitonin gene-related peptide (CGRP) from the same gene that encodes the hormone calcitonin. As CGRP-containing nerve fibers are prominent in skeleton, we evaluated the effects of CGRP on osteoblasts. Because the vasodilatory effect of neural CGRP in smooth muscle probably involves inhibition of unstimulated Ca2+ uptake, we examined the acute effects of CGRP on this parameter in rat osteoblastic cells. CGRP inhibits 45Ca2+ uptake in both UMR 106 osteosarcoma and RCOB-3 osteoblastic cells. This inhibition is rapid (0.5 min), occurs with an EC50 of 1 nM, and cannot be demonstrated in the presence of 0.1 mM diltiazem, a blocker of voltage-dependent Ca2+ channels. Depolarization of bone cells with high extracellular potassium (K+) also blocks the effect of CGRP on 45Ca2+ uptake, suggesting a central role for K+ channels in mediating this action. In agreement with this hypothesis, the effect of CGRP is blocked by 1 microM glybenclamide, a specific inhibitor of ATP-sensitive potassium (K(ATP)) channels, or by pretreatment of cells with 1 mM iodoacetic acid to deplete intracellular ATP. Blocking Ca2+-activated potassium channels with 1 mM tetraethylammonium does not prevent CGRP's effect. Pinacidil, a specific activator of K(ATP) channels, mimics CGRP's effect. Both CGRP and pinacidil also produce a small significant stimulation of cellular Ca2+ efflux in UMR 106 cells. These data suggest that inhibition of diltiazem-sensitive Ca2+ channels occurs secondary to the hyperpolarization engendered by CGRP activation of K(ATP) channels in osteoblastic cells, an effect similar to that of CGRP on smooth muscle cells.

Adenosine Triphosphate↗
PubMed1996

Implementing therapist-driven protocols.

In January of 1993, as part of a hospital-wide cost-reduction strategy, the University of California San Diego (UCSD) Medical Center Respiratory Care Department implemented a patient-driven protocol program designed to utilize the assessment skills and judgments of respiratory care staff, within physician-approved guidelines. This program produced a 60% reduction in the use of hand-held nebulizer therapy and chest physical therapy in the institution, with a substantial decrease in operational expenses. This article describes key elements of the implementation of protocol-driven programs, provides examples from the UCSD experience, and offers insights gained from others who have been successful agents of change. It describes patient-driven protocols, how they can be implemented, the barriers to and promoters of such protocols, and what the results can be for a respiratory care department.

Clinical Protocols↗
PubMed1995

Silent genes in bacteria: the previously designated 'cryptic' ilvHI locus of 'Salmonella typhimurium LT2' is active in natural isolates.

Gene ilvG in Escherichia coli K-12 and ilvI in 'Salmonella typhimurium LT2' (S. enterica serotype Typhimurium, strain LT2) are inactive due to frameshift or nonsense mutations, respectively. These inactive genes have been suggested to be part of 'cryptic' genetic systems which are defined as being of long-term regulatory and evolutionary significance. We have shown that the nonsense mutation in ilvI is present only in derivatives of the laboratory strain 'S. typhimurium LT2'. All natural isolates of Salmonella examined have an arginine codon at the corresponding location of their ilvI sequences. Further, two randomly selected natural isolates of serotype Typhimurium are shown to each have an active ALS III isozyme. Our findings strongly suggest that the only Salmonella strains which lack a functional ilvHI locus are LT2 isolates. We suggest that the mutations leading to inactivation of both ilvI in 'S. typhimurium LT2' and ilvG in E. coli K-12 are more likely to have been acquired during laboratory storage and/or cultivation, rather than representing cryptic systems of gene regulation.

Alleles↗
PubMed1995

1,25-Dihydroxyvitamin D3 promotes prostaglandin E1-induced differentiation of HL-60 cells.

Human promyelocytic HL-60 cells can be induced by biochemical agents to differentiate in vitro towards divergent types of myelomonocytic cells. It has been reported that prostaglandin E1 (PGE1) can induce granulocytic differentiation and that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) can induce monocytic differentiation. We have now examined the effects of these compounds, both alone and in combination, on HL-60 cell differentiation. PGE1 (1 microgram/ml) or 1,25(OH)2D3 (10 nM) each inhibited cell proliferation over 48-96 hours of treatment, but combined treatment with both agents was necessary to produce a strong inhibition. The percentage of HL-60 cells that can reduce nitroblue tetrazolium (NBT) (a characteristic index of early monocytic or granulocytic differentiation) increased 13-fold within 72 hours of PGE1 treatment, and 1,25(OH)2D3 produced a five-fold stimulation. However, combined treatment (PGE1 plus 1,25(OH)2D3) produced a dramatic 35-fold increase. HL-60 cells did not produce significant levels of nitric oxide (NO) before 48 hours in culture, and treatment with PGE1 or 1,25(OH)2D3 did not significantly increase cellular NO elaboration over control levels. However, combined treatment produced a striking 12-fold increase over control levels. Similarly, combined treatment was necessary to obtain the maximal time-dependent stimulation of cellular lactate dehydrogenase (LDH) activity (a marker of granulocytic differentiation) as well as acid phosphatase (ACP) activity. During this same period of time, PGE1, but not 1,25(OH)2D3, markedly stimulated cellular elaboration of interleukin (IL)-1 alpha, IL-6, and tumor necrosis factor (TNF)-alpha, and 1,25(OH)2D3 cotreatment strongly augmented these effects. Thus, combined treatment with 1,25(OH)2D3 plus PGE1 generally augmented the apparent conversion of these cells, producing synergistic (multiplicative) or additive effects. Furthermore, PGE1 induced within 48 hours the more general phenotypic changes classically associated with the differentiation of these cells: increased expression of chloroacetate esterase (ChAE) (a granulocytic marker), decreases in the nuclear/cytoplasmic ratio (characteristic of development beyond the promyelocyte/myelocyte stage), and major alterations in morphology from floating spherical cells to loosely adherent, elliptical polygons. 1,25(OH)2D3 had little effect itself on most of these parameters, but augmented the morphological changes induced by PGE1 treatment. Within 48 hours, the ability of these cells to reduce the tetrazolium salt WST-1, a general measure of cellular metabolic activity, was increased by PGE1, but not by 1,25(OH)2D3; however, the combination of 1,25(OH)2D3 and PGE1 again produced the strongest stimulation. Similarly, only PGE1 significantly reduced intracellular ATP levels, but combined treatments produced a more pronounced decrease. In summary, our findings suggest that PGE1, not 1,25(OH)2D3, is sufficient to promote rapid in vitro differentiation of HL-60 cells along the granulocyte pathway; however, the PGE1-induced conversion of these cells is markedly augmented by cotreatment with 1,25(OH)2D3. In addition, these converted HL-60 cells preferentially utilize the glycolytic pathway, rather than the citric acid cycle, for production of ATP, a metabolic characteristic that resembles that described for mature granulocytes.

Acid Phosphatase↗
PubMed1995

Protein tyrosine phosphorylation induced by epidermal growth factor and insulin-like growth factor-I in a rat clonal dental pulp-cell line.

Both epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) produce a dose-dependent stimulation in the rate of cell division in a rat clonal dental pulp-cell line (RDP 4-1). To elucidate the initial mitogen-induced cellular events that may mediate mitogenic action, the effects of EGF and IGF-I on cellular protein tyrosine phosphorylation were examined. In a dose-dependent manner, EGF (1-100 ng/ml) transiently stimulated tyrosine phosphorylation in four major proteins with apparent molecular weights of 220, 180, 140 and 120 kDa, and in five other more minor proteins (90, 80, 65, 55 and 44 kDa). IGF-I (1-100 ng/ml) dose-dependently stimulated the tyrosine phosphorylation of 160- and 140-kDa proteins, and had a smaller effect on the 80-, 65- and 44 kDa proteins. In contrast to the action of EGF, IGF-I-induced tyrosine phosphorylation was sustained for more than 60 min, particularly that of the 160-kDa phosphoprotein. From the results of specific immunoprecipitation/Western-blot analyses, the 180-kDa EGF-sensitive protein could be identified as the EGF receptor (EGF-R). Among the IGF-I-sensitive pulp cell proteins, the 160-kDa protein was identified as insulin-receptor substrate-1. Both mitogenic treatments stimulated the tyrosine phosphorylation of a weak, 44-kDa protein, which we have identified as the extracellular signal-regulated kinase-1. Despite the presence of phosphoproteins of the correct size, neither the IGF-I receptor (IGF-I-R) nor the phospholipase C gamma-isoform could be identified as tyrosine kinase substrates in either treatment. Pretreatment with the tyrosine kinase inhibitor genistein (20 micrograms/ml) significantly inhibited EGF- and IGF-I-induced tyrosine phosphorylation in permeabilized RDP 4-1 cells, and the tyrosine phosphatase inhibitor orthovanadate (1 mM) significantly prolonged the duration of the mitogen-stimulated tyrosine phosphorylation in both intact or permeabilized cells. Phorbol 12-myristate 13-acetate (100 nM), which activates protein kinase C (PKC), inhibited the tyrosine phosphorylation induced by either growth factor. This action was blocked by pretreatment with staurosporine (200 nM, 15 min), a selective PKC inhibitor. However, neither removing external Ca2+ with EGTA (1 mM) nor inducing Ca2+ influx with A23187 ionophore (2 microM) significantly altered EGF- or IGF-I-induced phosphorylation. These findings strongly suggest that authentic EGF-R and IGF-I-R on RDP 4-1 cells are coupled to complex, tyrosine kinase-mediated, intracellular signalling systems that are sensitive to a PKC-dependent mechanism. EGF- and IGF-I-induced tyrosine phosphorylation cascades may have important roles in vivo in the regulation of dental pulp-cell proliferation and ultimately may affect dentine formation.

Animals↗
PubMed1995

Carboxyfluorescein and biotin neuromedin C analogues: synthesis and applications.

Two neuromedin C (NC) analogues were constructed by Fmoc synthesis and in situ coupling of 4(5)-carboxyfluorescein or biotin to the N-terminus. Both displayed full agonism in an amylase release assay and cross-reacted fully with a NC-specific antiserum. Biotin NC functioned in a streptavidin-capture ELISA. Carboxyfluorescein NC was used to probe receptor localization in rat stomach. Specific NC binding sites, which did not interact with substance P, angiotensin I, or neurokinin A, were labeled in the antrum. Identity of NC binding sites was confirmed by microautoradiography. The specifically labeled cells were all found in the lamina propria and at least some of cells were identified as eosinophils.

Amylases↗
PubMed1995

Diverse actions of calcitonin gene-related peptide on intracellular free Ca2+ concentrations in UMR 106 osteoblastic cells.

Calcitonin gene-related peptide (CGRP) was examined for its effects on intracellular free Ca2+ concentration ([Ca2+]i) in UMR 106 osteoblast-like cells. Cells loaded with the Ca2+ dye FURA-2 dose-dependently responded to CGRP (1-100 nM) with transient two-fold increases in [Ca2+]i. An intracellular source for this Ca2+ transient was suggested by the failure of membrane depolarization with high extracellular K+ or acute depletion of extracellular Ca2+ ([Ca2+]e) with EGTA to attenuate this response. After cells were incubated for 45 min with 0.1 mM extracellular Ca2+ to deplete intracellular Ca2+ stores, CGRP produced a 25-30% decrease in [Ca2+]i rather than a transient increase. This calcium decrease was mimicked by membrane depolarization or by pinacidil, a specific activator of adenosine triphosphate (ATP)-sensitive potassium (KATP) channels, and blocked by glybenclamide, a specific blocker of KATP channels. Our data suggest that CGRP has diverse Ca2+ regulatory effects in UMR 106 cells, mobilizing Ca2+ from intracellular stores via classical signaling while possibly promoting cellular Ca2+ efflux or inhibiting uptake through voltage-dependent Ca2+ channels via KATP-mediated hyperpolarization.

Adenosine Triphosphate↗
PubMed1995

Out-of-hospital provider use of epinephrine for allergic reactions: pilot program.

OBJECTIVE: To describe experience with an out-of-hospital provider program for the recognition and field management of allergic reactions by advanced life support (ALS) and basic life support (BLS) providers. METHODS: Data sheets completed between June 1, 1988, and August 31, 1993, and records from receiving sites (physicians' offices or EDs) were reviewed for information regarding the presentation of the allergic reaction, the time course and treatment provided out of hospital, and the clinical outcome at the receiving health care facility. RESULTS: Thirty-seven data sheets were completed during the study period. Fourteen (38%) of the providers were BLS providers. The epinephrine was supplied from the emergency medical services (EMS) provider's personal kit in 35% of the cases, from an EMS vehicle in 57% of the cases, and by the patient in 8% of the cases. Availability of the kits allowed administration of epinephrine prior to the arrival of the first EMS vehicle in 41% of the instances and prior to physician on-line medical command in 65% of all the instances (predominantly by BLS providers). Overall, 77% of the patients experienced alleviation of their symptoms of respiratory difficulty, swelling, or rash after epinephrine administration, while 20% were unchanged and 3% worsened. All patients receiving epinephrine had an ED diagnosis of allergic reaction, and no adverse event was encountered on follow-up of the patients treated. CONCLUSIONS: Severe allergic reactions can be reliably identified and safely managed by out-of-hospital providers, including BLS providers. Providing personal anaphylactic treatment kits and increasing the pool of providers trained to manage allergic reactions (including BLS providers) can often decrease the time to treatment.

Adrenergic Agonists↗
PubMed1993

UDP-sugar hydrolase isozymes in Salmonella enterica and Escherichia coli: silent alleles of ushA in related strains of group I Salmonella isolates, and of ushB in wild-type and K12 strains of E. coli, indicate recent and early silencing events, respectively.

Escherichia coli contains a single periplasmic UDP-glucose hydrolase (5'-nucleotidase) encoded by ushA. Salmonella enterica, serotype Typhimurium, also contains a single UDP-glucose hydrolase but, in contrast to E. coli, it is membrane-bound and is encoded by the non-homologous ushB gene; Salmonella enterica (Typhimurium) also contains a silent allele of the ushA gene (ushA0). In this report, we show that nearly all natural isolates of Salmonella contain both UDP-sugar hydrolases, i.e. they are UshA+ UshB+. The only exceptions are all from sub-group I (S. gallinarum, S. pullorum, and most Typhimurium strains), are UshA- UshB+, and several have been shown to contain an ushA0 allele. These data, together with the fact that these latter strains are closely related genetically, strongly suggests a recent silencing mutation(s). We also report the presence in E. coli K-12, and in natural isolates of E. coli, of a DNA sequence which is homologous to the ushB gene of Salmonella; since E. coli does not contain UshB activity, we tentatively refer to this sequence as ushB0. Since all E. coli strains investigated are UshB-, we conclude that the silencing mutation(s) occurred relatively early following the divergence of Escherichia coli and Salmonella from a common ancestor that was ushA+ ushB+.

Alleles↗
PubMed1993

Membrane localisation of a UDP-sugar hydrolase, in Salmonella, is by an uncleaved N-terminal signal peptide.

Most isolates of Salmonella contain two unrelated UDP-sugar hydrolases, one of which, encoded by the ushB gene, is inner membrane-associated. Previous studies showed that this enzyme contains a typical N-terminal signal peptide; the evidence also indicated, however, that this peptide is not cleaved, and serves to anchor the UshB protein in the inner membrane. In this report, we present strong evidence that this is indeed the case by using ushB'-'blaM fusions to demonstrate that this signal peptide is capable of localising beta-lactamase to the inner membrane. We also present evidence that UshB is located on the exterior (periplasmic) side of the membrane, and hence has an 'N-terminus inside/C-terminus outside' membrane orientation, consistent with a role in the degradation of external substrates.

Amino Acid Sequence↗