26
|
Thyagarajan SK, Sharma V, Austin S, Lasoye T, Hunter P. An audit of corneal abrasion management following the introduction of local guidelines in an accident and emergency department. Emerg Med J 2006; 23:526-9. [PMID: 16794094 PMCID: PMC2579545 DOI: 10.1136/emj.2005.032557] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND AND OBJECTIVES Corneal abrasions are a common presentation to accident and emergency (A&E) departments. Patients can be treated and discharged by A&E staff without the need for an ophthalmologist's attention; complicated cases, however, should be recognised and referred. Inexperience and limited training in ophthalmology may lead to suboptimal patient care and inappropriate use of ophthalmology outpatient clinics. Issues of poor documentation may also arise. The purpose of this audit was to assess the effect of guidelines on the management of corneal abrasion by A&E staff. METHODS A retrospective case note audit was performed to assess current management of corneal abrasions. Guidelines for management of corneal abrasions were formulated following a literature search and collaboration between A&E and ophthalmology staff. A prospective case note audit was undertaken to assess management after introduction of the guidelines. RESULTS A total of 51 cases were audited before the introduction of the guidelines and 57 cases after. Following the introduction of the guidelines documentation of visual acuity increased to 93% and specific enquiry into contact lens wear rose from 35.3% to 71.9%. A&E staff stopped giving out local anaesthetic eye drops. The follow up profile also improved; appropriate patient discharges increased by 40% whereas inappropriate referrals to eye clinic dropped by 75%. More patients were given abrasion advice (a 101% increase). CONCLUSIONS A&E staff members are capable of managing corneal abrasions if they are given guidance and some training. This audit identified shortcomings in current management and showed that guidelines can significantly improve clinical practice.
Collapse
|
27
|
Mendonca C, Madan V, Austin S, Beck MH. Occupational contact urticaria from walnut associated with hand eczema. Contact Dermatitis 2005; 53:173-4. [PMID: 16128763 DOI: 10.1111/j.0105-1873.2005.0407f.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
28
|
Austin S. Staffing: know your liability. Nurs Manag (Harrow) 2004; 31:19. [PMID: 15127501 DOI: 10.1097/00006247-200007000-00017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Read this case of poor staffing judgment regarding outside agency employees and answer the questions, then check your answers at http://www.nursingmanagement.com.
Collapse
|
29
|
Chalkiadis GA, Eyres RL, Cranswick N, Taylor RH, Austin S. Pharmacokinetics of levobupivacaine 0.25% following caudal administration in children under 2 years of age † †Declaration of interest. This work was funded by Chiroscience Limited, Cambridge, UK. Br J Anaesth 2004; 92:218-22. [PMID: 14722171 DOI: 10.1093/bja/aeh051] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Levobupivacaine, the S(-)enantiomer of racemic bupivacaine is less cardiotoxic than racemic bupivacaine and the R(+)enantiomer dexbupivacaine, while retaining similar local anaesthetic properties and potency to racemic bupivacaine. The pharmacokinetic profiles of the two bupivacaine enantiomers differs and that of racemic bupivacaine may be age dependent. We examined the pharmacokinetics of levobupivacaine after its single shot caudal epidural administration in children. METHODS An open-label phase 2 study was undertaken to examine the pharmacokinetics of levobupivacaine 0.25% 2 mg kg(-1) in 49 children aged less than 2 yr, after single shot caudal epidural administration. Plasma concentrations were determined at intervals up to 60 min after caudal injection. RESULTS Time to peak plasma concentration (T(max)) ranged between 5 and 60 min (median 30 min) and was reached later in children aged less than 3 months (P<0.005). Peak plasma concentration (C(max)) ranged between 0.41 and 2.12 micro g ml(-1) (median 0.80, mean (SD) 0.91 (0.40) micro g ml(-1)). CONCLUSION After the caudal epidural administration of levobupivacaine 2 mg kg(-1) in children less than 2 yr of age, C(max) was within the accepted safe range for racemic bupivacaine. T(max) varied and occurred later in some children, particularly those aged less than 3 months. Sampling in future pharmacokinetic studies in this age group should extend beyond 60 min.
Collapse
|
30
|
Taylor R, Eyres R, Chalkiadis GA, Austin S. Efficacy and safety of caudal injection of levobupivacaine, 0.25%, in children under 2 years of age undergoing inguinal hernia repair, circumcision or orchidopexy. Paediatr Anaesth 2003; 13:114-21. [PMID: 12562483 DOI: 10.1046/j.1460-9592.2003.01036.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Levobupivacaine is the S(-)-enantiomer of racemic bupivacaine. Evidence suggests that it is less cardiotoxic than racemic bupivacaine and the R(+)-enantiomer, dexbupivacaine, while retaining similar local anaesthetic properties and potency to racemic bupivacaine. METHODS This was an open study designed to assess the efficacy and safety of 0.25% levobupivacaine administered as a caudal injection at a dose of 2 mg.kg(-1) to 49 paediatric patients aged less than 2 years old undergoing circumcision (group 1), or hernia repair or orchidopexy (group 2). RESULTS Adequate analgesia (an increase of <20% in pulse or respiratory rate compared with baseline and an absence of gross movement on application of surgical stimulus) was achieved in 43/48 patients evaluable for efficacy (89.6%). All 22 patients in the circumcision group had adequate analgesia, and two of these patients did not require additional analgesia. The mean time to the use of additional analgesia was 7.3 h. Only one event (a mild rash) was considered possibly related to study medication. CONCLUSIONS Levobupivacaine is a promising new local anaesthetic agent for pain management in paediatric patients and appears to offer similar anaesthetic efficacy to racemic bupivacaine with a potentially improved tolerability profile.
Collapse
|
31
|
FitzGerald GA, Cheng Y, Austin S. COX-2 inhibitors and the cardiovascular system. Clin Exp Rheumatol 2001; 19:S31-6. [PMID: 11695249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Cyclooxygenase-2 selective inhibitors (coxibs) represent a new class of non steroidal anti-inflammatory drugs that exhibit preference for inhibition of cyclooxygenase-2 (COX-2), the COX isoform thought to account largely for prostanoid formation in inflammation. We review the divergent incidence of cardiovascular events derived from the two large clinical trials of coxibs, the Vioxx Gastrointestinal Outcomes Research Trial (VIGOR) and the Celecoxib Long-term Arthritis Safety Study (CLASS), in the context of current understanding of relevant clinical and basic pharmacology. The incidence of cardiovascular events was higher in patients receiving rofecoxib than in those receiving naproxen in VIGOR and did not differ between the groups in CLASS. By contrast, while the primary gastrointestinal (GI) endpoint comparison favored rofecoxib in VIGOR, no significant difference in the incidence of the primary GI endpoint was evident between celecoxib and two NSAID comparators not attained in CLASS. The cardiovascular results in VIGOR may have resulted from chance, a cardioprotective effect of naproxen, or suppression of prostacyclin but not thromboxane on rofecoxib. Differences in cardiovascular outcome between the two trials may also have resulted either from chance, or from aspects of the trial design (such as the use of aspirin by roughly one-fifth of the participants in CLASS), or from differences in the COX-2 selectivity or other pharmacology of the coxibs. Individuals who warrant low-dose aspirin for cardioprotection may have less likelihood of a GI event if they combine aspirin with rofecoxib, rather than a traditional NSAID. However, evidence addressing directly this hypothesis is currently unavailable. On the other hand, coxib consumption alone does not currently warrant initiation of a cardioprotective regimen, such as low-dose aspirin.
Collapse
|
32
|
Austin S. A safe standard of care for medication administration. Nurs Manag (Harrow) 2001; 32:12. [PMID: 17933067 DOI: 10.1097/00006247-200109000-00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Review caregivers' degree of responsibility and accountability when administering medication.
Collapse
|
33
|
Sergueev K, Yu D, Austin S, Court D. Cell toxicity caused by products of the p(L) operon of bacteriophage lambda. Gene 2001; 272:227-35. [PMID: 11470529 DOI: 10.1016/s0378-1119(01)00535-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Induction of a lambda prophage causes the death of the host cell even in the absence of phage replication and lytic functions due to expression of functions from the lambda p(L) operon. We genetically modified the lambda prophage to determine which lambda p(L) operon functions were involved in cell killing. Viability assays and flow cytometry were used to monitor cell death and filamentation. The kil gene was shown to cause cell death and filamentation as described previously. Another killing activity was mapped within the p(L) operon to the gam gene. Inspection of the DNA sequence showed that there are two possible translation start points for both kil and gam. In both cases, the shorter of the two possible products could cause cell killing. The shorter products were also sufficient for the known filamentation and recombination activities of the respective Kil and Gam functions. The expression level of the p(L) operon is down-regulated by Cro repressor. In the absence of Cro, higher p(L) expression levels allow either Kil or Gam to be lethal or growth inhibitory, whereas at lowered expression in Cro-repressed conditions, only Kil is lethal. The filamentation function of Kil and recombination activity of Gam are unaffected at Cro-repressed levels of expression.
Collapse
|
34
|
Austin S. Proper equipment use makes or breaks care. Nurs Manag (Harrow) 2001; 32:16. [PMID: 15103862 DOI: 10.1097/00006247-200106000-00010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Review the following case that addresses proper staff education regarding equipment usage and standards. Test your knowledge with the following questions, then check your answers at http://www.nursingmanagement.com.
Collapse
|
35
|
Sawitzke J, Austin S. An analysis of the factory model for chromosome replication and segregation in bacteria. Mol Microbiol 2001; 40:786-94. [PMID: 11401686 DOI: 10.1046/j.1365-2958.2001.02350.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent advances in microscopy have given us important clues as to the nature of chromosome segregation in bacteria. Most current observations favour the view that the process is co-replicational: DNA replication forks are anchored at the cell centre, and the newly replicated DNA is moved towards the cell poles. This scheme can account for orderly segregation even at high growth rates where multiple replication cycles overlap. We argue that there are five distinct activities directly involved in co-replicational segregation dynamics. These we refer to as Push, Direct, Condense, Hold and Clear. We attempt to assign one of these roles to each protein implicated in chromosome segregation. The proposed process is very different from mitosis in eukaryotic cells and perhaps more closely resembles the formation of separate sister chromatids during DNA replication.
Collapse
|
36
|
|
37
|
Austin S. Policies and procedures: friend or foe? Part 3. Nurs Manag (Harrow) 2001; 32:22-3. [PMID: 15103819 DOI: 10.1097/00006247-200103000-00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Review a case where policy and procedure violation resulted in patient death and hospital liability. Test your knowledge with the following questions, then check your answers at http://www.nursingmanagement.com.
Collapse
|
38
|
Fabre JE, Nguyen M, Athirakul K, Coggins K, McNeish JD, Austin S, Parise LK, FitzGerald GA, Coffman TM, Koller BH. Activation of the murine EP3 receptor for PGE2 inhibits cAMP production and promotes platelet aggregation. J Clin Invest 2001; 107:603-10. [PMID: 11238561 PMCID: PMC199422 DOI: 10.1172/jci10881] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The importance of arachidonic acid metabolites (termed eicosanoids), particularly those derived from the COX-1 and COX-2 pathways (termed prostanoids), in platelet homeostasis has long been recognized. Thromboxane is a potent agonist, whereas prostacyclin is an inhibitor of platelet aggregation. In contrast, the effect of prostaglandin E2 (PGE2) on platelet aggregation varies significantly depending on its concentration. Low concentrations of PGE2 enhance platelet aggregation, whereas high PGE2 levels inhibit aggregation. The mechanism for this dual action of PGE2 is not clear. This study shows that among the four PGE2 receptors (EP1-EP4), activation of EP3 is sufficient to mediate the proaggregatory actions of low PGE2 concentration. In contrast, the prostacyclin receptor (IP) mediates the inhibitory effect of higher PGE2 concentrations. Furthermore, the relative activation of these two receptors, EP3 and IP, regulates the intracellular level of cAMP and in this way conditions the response of the platelet to aggregating agents. Consistent with these findings, loss of the EP3 receptor in a model of venous inflammation protects against formation of intravascular clots. Our results suggest that local production of PGE2 during an inflammatory process can modulate ensuing platelet responses.
Collapse
|
39
|
Money T, Barrett J, Dixon R, Austin S. Protein-protein interactions in the complex between the enhancer binding protein NIFA and the sensor NIFL from Azotobacter vinelandii. J Bacteriol 2001; 183:1359-68. [PMID: 11157949 PMCID: PMC95010 DOI: 10.1128/jb.183.4.1359-1368.2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The enhancer binding protein NIFA and the sensor protein NIFL from Azotobacter vinelandii comprise an atypical two-component regulatory system in which signal transduction occurs via complex formation between the two proteins rather than by the phosphotransfer mechanism, which is characteristic of orthodox systems. The inhibitory activity of NIFL towards NIFA is stimulated by ADP binding to the C-terminal domain of NIFL, which bears significant homology to the histidine protein kinase transmitter domains. Adenosine nucleotides, particularly MgADP, also stimulate complex formation between NIFL and NIFA in vitro, allowing isolation of the complex by cochromatography. Using limited proteolysis of the purified proteins, we show here that changes in protease sensitivity of the Q linker regions of both NIFA and NIFL occurred when the complex was formed in the presence of MgADP. The N-terminal domain of NIFA adjacent to the Q linker was also protected by NIFL. Experiments with truncated versions of NIFA demonstrate that the central domain of NIFA is sufficient to cause protection of the Q linker of NIFL, although in this case, stable protein complexes are not detectable by cochromatography.
Collapse
|
40
|
Abstract
Review a case where policy and procedure breaches resulted in disaster. Test your knowledge with the following questions, then check your answers at http://www.nursingmanagement.com.
Collapse
|
41
|
Austin S. Policies and procedures: friend or foe? Part 1. Nurs Manag (Harrow) 2001; 32:15. [PMID: 15103775 DOI: 10.1097/00006247-200101000-00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Policy and procedure wording can make or break caregiving accountability. Test your knowledge with the following questions, then check your answers at http://www.nursingmanagement.com.
Collapse
|
42
|
Austin S, McAtamney D, Maguire P, Loan P, Crean PM. A study to assess the feasibility of using glucometer measurement of blood glucose on fresh blood sampled from the surgical field. Paediatr Anaesth 2000; 10:691-2. [PMID: 11119219 DOI: 10.1111/j.1460-9592.2000.ab01h.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
43
|
FitzGerald GA, Austin S, Egan K, Cheng Y, Pratico D. Cyclo-oxygenase products and atherothrombosis. Ann Med 2000; 32 Suppl 1:21-6. [PMID: 11209977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
The advent of selective inhibitors of the cyclo-oxygenase (COX)-2 enzyme has afforded the opportunity to reduce the incidence of gastrointestinal complications of traditional nonsteroidal anti-inflammatory drugs (NSAIDs). The widespread use of these drugs has increased interest in their role in the cardiovascular system. Although deletion of the prostacyclin receptor (the IP) accelerates atherogenesis in the mouse, retention of one copy of the IP is atheroprotective. This is consistent with the failure of biochemically defined, selective doses of a COX-2 inhibitor to accelerate atherogenesis in the mouse, despite suppressing prostacyclin biosynthesis by roughly 60%. Inhibition of both COX isozymes, by contrast, markedly retards atherogenesis. Consistent with these observations, antagonism of the thromboxane receptor (the TP) retards atherogenesis and diminishes the proliferative response to vascular injury in the mouse. Even partial suppression of prostacyclin (without coincident inhibition of platelet COX-1-dependent thromboxane formation) by COX-2 inhibitors may be undesirable in acute vascular occlusive syndromes. However, these drugs are unlikely to accelerate progression of the underlying vascular disease. By contrast, the effects of TP antagonists, aspirin, and even traditional NSAIDs on atherosclerotic plaque progression merit further evaluation in humans.
Collapse
|
44
|
Brendler T, Sawitzke J, Sergueev K, Austin S. A case for sliding SeqA tracts at anchored replication forks during Escherichia coli chromosome replication and segregation. EMBO J 2000; 19:6249-58. [PMID: 11080170 PMCID: PMC305820 DOI: 10.1093/emboj/19.22.6249] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
SeqA is an Escherichia coli DNA-binding protein that acts at replication origins and controls DNA replication. However, binding is not exclusive to origins. Many fragments containing two or more hemi-methylated GATC sequences bind efficiently. Binding was optimal when two such sequences were closely apposed or up to 31 bases apart on the same face of the DNA helix. Binding studies suggest that neighboring bound proteins contact each other to form a complex with the intervening DNA looped out. There are many potential binding sites distributed around the E.coli chromosome. As replication produces a transient wave of hemi-methylation, tracts of SeqA binding are likely to associate with each fork as replication progresses. The number and positions of green fluorescent protein-SeqA foci seen in living cells suggest that they correspond to these tracts, and that the forks are tethered to planes of cell division. SeqA may help to tether the forks or to organize newly replicated DNA into a structure that aids DNA to segregate away from the replication machinery.
Collapse
|
45
|
Murphy C, Davidson TM, Jellison W, Austin S, Mathews WC, Ellison DW, Schlotfeldt C. Sinonasal disease and olfactory impairment in HIV disease: endoscopic sinus surgery and outcome measures. Laryngoscope 2000; 110:1707-10. [PMID: 11037830 DOI: 10.1097/00005537-200010000-00026] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To investigate the effects of ESS (ESS) on olfactory impairment, disease-specific symptoms, and general quality of well-being In HIV+ patients with sinonasal disease. STUDY DESIGN Study 1: Nasal cytology, rhinomanometry, nasal examination including endoscopy, disease-specific sinonasal symptoms, olfactory threshold sensitivity, and odor identification testing were performed before and after ESS in HIV+ patients with sinonasal complaints. Study 2: Quality of well-being was assessed before and after ESS in HIV+ patients with sinonasal complaints and controls. RESULTS Significant olfactory sensitivity loss persisted for patients with chronic sinusitis after ESS, suggesting that the impairment in these patients may be due to viral disease rather than inflammation. Significant improvement in other disease-specific symptom scores (nasal obstruction, nasal congestion, headache, sinus pain, etc.) and results of the general quality of well-being assessment showed ESS to be beneficial in the extended health management of HIV illness. CONCLUSIONS The current study indicated both olfactory dysfunction and subjective negative symptoms in HIV+ patients with chronic sinusitis. Although olfactory dysfunction remained, ESS was successful in providing marked alleviation of symptomatology in HIV+ patients with chronic sinusitis. The results support ESS as an appropriate treatment option for HIV+ patients with chronic sinusitis.
Collapse
|
46
|
Youngren B, Radnedge L, Hu P, Garcia E, Austin S. A plasmid partition system of the P1-P7par family from the pMT1 virulence plasmid of Yersinia pestis. J Bacteriol 2000; 182:3924-8. [PMID: 10869068 PMCID: PMC94575 DOI: 10.1128/jb.182.14.3924-3928.2000] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The complete sequence of the virulence plasmid pMT1 of Yersinia pestis KIM5 revealed a region homologous to the plasmid partition (par) region of the P7 plasmid prophage of Escherichia coli. The essential genes parA and parB and the downstream partition site gene, parS, are highly conserved in sequence and organization. The pMT1parS site and the parA-parB operon were separately inserted into vectors that could be maintained in E. coli. A mini-P1 vector containing pMT1parS was stably maintained when the pMT1 ParA and ParB proteins were supplied in trans, showing that the pMT1par system is fully functional for plasmid partition in E. coli. The pMT1par system exerted a plasmid silencing activity similar to, but weaker than those of P7par and P1par. In spite of the high degree of similarity, especially to P7par, it showed unique specificities with respect to the interactions of key components. Neither the P7 nor P1 Par proteins could support partition via the pMT1parS site, and the pMT1 Par proteins failed to support partition with P1parS or P7parS. Typical of other partition sites, supernumerary copies of pMT1parS exerted incompatibility toward plasmids supported by pMT1par. However, no interspecies incompatibility effect was observed between pMT1par, P7par, and P1par.
Collapse
|
47
|
Sayeed S, Reaves L, Radnedge L, Austin S. The stability region of the large virulence plasmid of Shigella flexneri encodes an efficient postsegregational killing system. J Bacteriol 2000; 182:2416-21. [PMID: 10762240 PMCID: PMC111302 DOI: 10.1128/jb.182.9.2416-2421.2000] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The large virulence plasmid pMYSH6000 of Shigella flexneri contains a determinant that is highly effective in stabilizing otherwise unstable plasmids in Escherichia coli. Expression of two small contiguous genes, mvpA and mvpT (formerly termed STBORF1 and STBORF2), was shown to be sufficient for stability. Mutations in mvpT abolished plasmid stability, and plasmids expressing only mvpT killed the cells unless mvpA was supplied from a separate plasmid or from the host chromosome. When replication of a plasmid carrying the minimal mvp region was blocked, growth of the culture stopped after a short lag and virtually all of the surviving cells retained the plasmid. Thus, the mvp system stabilizes by a highly efficient postsegregational killing (PSK) mechanism, with mvpT encoding a cell toxin and mvpA encoding an antidote. The regions that surround the mvp genes in their original context have an inhibitory effect that attenuates plasmid stabilization and PSK. The region encompassing the mvp genes also appears to contain an additional element that can aid propagation of a pSC101-based plasmid under conditions where replication initiation is marginal. However, this appears to be a relatively nonspecific effect of DNA insertion into the plasmid vector.
Collapse
|
48
|
Sawitzke JA, Austin S. Suppression of chromosome segregation defects of Escherichia coli muk mutants by mutations in topoisomerase I. Proc Natl Acad Sci U S A 2000; 97:1671-6. [PMID: 10660686 PMCID: PMC26494 DOI: 10.1073/pnas.030528397] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/1999] [Accepted: 12/06/1999] [Indexed: 11/18/2022] Open
Abstract
Escherichia coli muk mutants are temperature-sensitive and produce anucleate cells. A spontaneously occurring mutation was found in a DeltamukBkan mutant strain that suppressed the temperature-sensitive phenotype and mapped in or near topA, the gene that encodes topoisomerase I. Previously characterized topA mutations, topA10 and topA66, were found to be general suppressors of muk mutants: they suppressed temperature sensitivity and anucleate cell production of cells containing null or point mutations in mukB and null mutations in mukE or mukF. The suppression correlated with excess negative supercoiling by DNA gyrase, and the gyrase inhibitor, coumermycin, reversed it. Defects in topA allow 99% of cell division events in muk null mutants to proceed without chromosome loss or loss of cell viability. This observation imposes important limitations on models for Muk activity and is consistent with a role for MukBEF in chromosome folding and DNA condensation.
Collapse
|
49
|
Austin S. What's your liability in a survey? Nurs Manag (Harrow) 2000; 31:14. [PMID: 10827686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
You have liability exposure for regulatory issues when federal, state, and local officials, as well as other organization, such as JCAHO, survey your facility. Answer the questions about the following survey scenario below, then check your answers at www.nursingmanagement.com.
Collapse
|
50
|
Jones C, Lemercinier X, Crane DT, Gee CK, Austin S. Spectroscopic studies of the structure and stability of glycoconjugate vaccines. DEVELOPMENTS IN BIOLOGICALS 2000; 103:121-36. [PMID: 11214231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
|