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Biomedical subjects

S McGovern

Publications and source records attributed to S McGovern.

15 recordsLinked to original sources
PubMed2006

Functional dissection of YabA, a negative regulator of DNA replication initiation in Bacillus subtilis.

The regulation of initiation of DNA replication is crucial to ensure that the genome is replicated only once per cell cycle. In the Gram-positive bacterium Bacillus subtilis, the function of the YabA protein in initiation control was assigned based on its interaction with the DnaA initiator and the DnaN sliding clamp in the yeast two-hybrid and on the overinitiation phenotype observed in a yabA null strain. However, YabA is unrelated to known regulators of initiation and interacts with several additional proteins that could also be involved directly or not in initiation control. Here, we investigated the specific role of YabA interactions with DnaA and DnaN in initiation control by identifying single amino acid changes in YabA that disrupted solely the interaction with DnaA or DnaN. These disruptive mutations delineated specific interacting surfaces involving a Zn2+-cluster structure in YabA. In B. subtilis, these YabA interaction mutations abolished both initiation control and the formation of YabA foci at the replication factory. Upon coexpression of deficient YabA mutants, mixed oligomers formed foci at the replisome and restored initiation control, indicating that YabA acts within a heterocomplex with DnaA and DnaN. In agreement, purified YabA oligomerized and formed complexes with DnaA and DnaN. These findings underscore the functional association of YabA with the replication machinery, indicating that YabA regulates initiation through coupling with the elongation of replication.

Bacillus subtilis↗
PubMed2005

Emergency department ultrasound (EDU): clinical adjunct or plaything?

BACKGROUND: Emergency department ultrasound (EDU) is a physician performed ultrasound service aimed at improving patient flow and diagnosis in the emergency department. METHODS: This paper describes the initial phase of the introduction of EDU with three illustrative case reports and a discussion on the pitfalls and benefits of EDU. RESULTS AND DISCUSSION: In three cases discussed here, the use of EDU facilitated treatment and reduced the need for formal radiological scanning. While there are drawbacks to EDU, we believe these are far outweighed by the advantages, and in a recent survey of emergency medicine consultants throughout Ireland, the vast majority were in favour of its introduction. CONCLUSION: EDU has become a routine part of our clinical practice, and although we are still on a learning curve with regard to its use, we have experienced significant benefits in patient care. With technological advances (such as improved image resolution and teleradiology) the potential for EDU will continue to expand, but training, practice, accreditation, and audit are essential.

Aged↗
PubMed2005

The right place in the right space? Awareness of site for needle thoracocentesis.

BACKGROUND: Invasive practical procedures require identification of surface anatomical landmarks to reduce risk of damage to other structures. Needle thoracocentesis has specific complications, which have been previously documented. An observational study was performed among emergency physicians to name the landmark for needle thoracocentesis and identify this point on a human volunteer as per Advanced Trauma and Life Support (ATLS) guidelines. RESULTS: A cohort of 25 emergency physicians was studied, 21 (84%) of which were ATLS certified. The correct landmark was named by 22 (88%). Only 15 (60%) correctly identified the second intercostal space on the human volunteer, all placing the needle medial to the midclavicular line, with a range of 3 cm. Two (8%) named and identified the site of needle pericardiocentesis; one (4%) named and identified the fifth intercostal space in the anterior axillary line. DISCUSSION: These results demonstrate a low accuracy among emergency physicians in identifying correct landmarks for needle thoracocentesis under elective conditions. Should greater emphasis be placed on competency based training in ATLS?

Chi-Square Distribution↗
PubMed2005

Survey of attitudes of senior emergency physicians towards the introduction of emergency department ultrasound.

INTRODUCTION: Emergency department ultrasound (EDU) is widely practised in the USA, Australia, parts of Europe, and Asia. EDU has been used in the UK since the late 1990s but as yet, few areas have established a practice. OBJECTIVES: To assess the current climate of opinion with respect to the practice, constraints, and establishment of EDU among emergency department (ED) consultants on the island of Ireland. METHODS: A postal questionnaire was formulated, piloted, and assessed for ambiguity by a sample of ED consultants and an independent non-ED consultant, prior to being mailed to all ED consultants in Ireland. RESULTS: Of the 58 consultants canvassed 46 (79%) responded. Of the respondents, 40 (87%) strongly agreed/agreed that EDU is appropriate and should be performed in the ED. Of these, 3 (7%) are currently performing EDU; 37 (80%) have not had formal training in EDU, however 42 (91%) support the establishment of national guidelines for training in focused ultrasound in the ED. Problems instituting EDU were often multifactorial. Commonly highlighted difficulties included financial issues (24 respondents, 52%) and radiology department support (16 respondents, 34%). Other cited problems include varying interdepartmental practices (15 respondents, 33%) and (for some EDs) low numbers of patients requiring EDU, with projected difficulties in skills maintenance. CONCLUSION: Despite the vast majority of ED consultants being in favour of EDU, very few actually perform it on a regular basis or have had any formal training. Highlighted difficulties in EDU implementation included financial constraints, lack of support from radiology departments, and lack of formal training.

Attitude of Health Personnel↗
PubMed2005

Relationship between Trendelenburg tilt and internal jugular vein diameter.

OBJECTIVES: To evaluate the relationship between Trendelenburg tilt and internal jugular vein (IJV) diameter, and to examine any cumulative effects of tilt on the IJV diameter. METHODS: Using a tilt table, healthy volunteers were randomised to Trendelenburg tilts of 10 degrees, 15 degrees, 20 degrees, 25 degrees, and 30 degrees. Ultrasound was used to measure and record the lateral diameter of the right IJV at the level of the cricoid cartilage. Following each reading the table was returned to the supine position. Balanced randomisation was used to assess cumulative tilt effects. RESULTS: A total of 20 healthy volunteers were recruited (10 men, 10 women). Mean supine IJV diameter was 13.5 mm (95% CI 12.8 to 14.1) and was significantly greater at 10 degrees (15.5 mm, 95% CI 14.9 to 16.1). There was no significant difference between 10 degrees and greater angles of tilt. The effect of the previous angle of tilt did not prove to be statistically significant. CONCLUSION: Increasing the degree of Trendelenburg tilt increases the lateral diameter of the IJV. Even a 10 degrees tilt is effective. The cumulative effect of tilt (that is, the effect of the previous angle) is not significant. Ultrasound guided cannulation is ideal, but in its absence Trendelenburg tilt will increase IJV diameter and improve the chance of successful cannulation. While 25 degrees achieved optimum distension, this may not be practical and may be detrimental (for example, risk of raised intracranial pressure).

Adult↗
PubMed2001

Early steps of Bacillus subtilis primosome assembly.

Primosomes are nucleoprotein assemblies designed for the activation of DNA replication forks. Their primary role is to recruit the replicative helicase onto single-stranded DNA. The "replication restart" primosome, defined in Escherichia coli, is involved in the reactivation of arrested replication forks. Binding of the PriA protein to forked DNA triggers its assembly. PriA is conserved in bacteria, but its primosomal partners are not. In Bacillus subtilis, genetic analysis has revealed three primosomal proteins, DnaB, DnaD, and DnaI, that have no obvious homologues in E. coli. Interestingly, they are involved in primosome function both at arrested replication forks and at the chromosomal origin. Our biochemical analysis of the DnaB and DnaD proteins unravels their role in primosome assembly. They are both multimeric and bind individually to DNA. Furthermore, DnaD stimulates DnaB binding activities. DnaD alone and the DnaD/DnaB pair interact specifically with PriA of B. subtilis on several DNA substrates. This suggests that the nucleoprotein assembly is sequential in the PriA, DnaD, DnaB order. The preferred DNA substrate mimics an arrested DNA replication fork with unreplicated lagging strand, structurally identical to a product of recombinational repair of a stalled replication fork.

Bacillus subtilis↗
PubMed2001

Psychological model for judicial decision making in emergency or temporary child placement.

In emergencies, family court judges must often make rapid decisions, without benefit of thorough information, that have significant impact on people's lives. Action-oriented research was used to develop a model that would bring psychosocial factors to the legal system for the purpose of enhancing the judicial decision-making process in emergency and temporary child placement cases.

Child↗
PubMed2001

DnaB, DnaD and DnaI proteins are components of the Bacillus subtilis replication restart primosome.

Phenotypes of Bacillus subtilis priA mutants suggest that they are deficient in the restart of stalled chromosomal replication forks. The presumed activity of PriA in the restart process is to promote the assembly of a multiprotein complex, the primosome, which functions to recruit the replication fork helicase onto the DNA. We have proposed previously that three proteins involved in the initiation of replication at oriC in B. subtilis, DnaB, DnaD and DnaI, are components of the PriA primosome in this bacterium. However, the involvement of these proteins in replication restart has not yet been studied. Here, we describe dnaB mutations that suppress the phenotypes of B. subtilis priA mutants. In a representative mutant, the DnaC helicase is loaded onto single-stranded DNA in a PriA-independent, DnaD- and DnaI-dependent manner. These observations confirm that DnaB, DnaD and DnaI are primosomal proteins in B. subtilis. Moreover, their involvement in the suppression of priA phenotypes shows that they participate in replication fork restart in B. subtilis.

Bacillus subtilis↗
PubMed1998

PcrA is an essential DNA helicase of Bacillus subtilis fulfilling functions both in repair and rolling-circle replication.

The only DNA helicase essential for Escherichia coli viability is DnaB, the chromosome replication for helicase. In contrast, in Bacillus subtilis, in addition to the DnaB counterpart called DnaC, we have found a second essential DNA helicase, called PcrA. It is 40% identical to the Rep and UvrD DNA helicases of E. coli and 61% identical to the PcrA helicase of Staphylococcus aureus. This gene is located at 55 degree on the chromosome and belongs to a putative operon together with a ligase gene (lig) and two unknown genes named pcrB and yerH. As PcrA was essential for cell viability, conditional mutants were constructed. In such mutants, chromosomal DNA synthesis was slightly decreased upon PcrA depletion, and rolling-circle replication of the plasmid pT181 was inhibited. Analysis of the replication intermediates showed that leading-strand synthesis of pT181 was prevented upon PcrA depletion. To compare PcrA with Rep and UvrD directly, the protein was produced in rep and uvrD mutants of E. coli. PcrA suppressed the UV sensitivity defect at a uvrD mutant but not its mutator phenotype. Furthermore, it conferred a Rep-phenotype on E. coli. Altogether, these results show that PcrA is an helicase used for plasmid rolling-circle replication and suggest that it is also involved in UV repair.

Adenosine Triphosphatases↗
PubMed1997

Replication terminus for DNA polymerase I during initiation of pAM beta 1 replication: role of the plasmid-encoded resolution system.

Replication of plasmid pAM beta 1 is initiated by DNA polymerase I (Pol I) and completed by DNA polymerase III holoenzyme contained in the replisome machinery. In this study we report that initiation of DNA replication generates D-loop structures containing the nascent leading strand paired to its template, and that D-loop extension is arrested approximately 230 bp from the initiation site of DNA synthesis in the presence of the plasmid-encoded resolvase. In vitro and in vivo data suggest that this arrest is caused by a collision between Pol I and the resolvase bound to its target. As the arrested D-loop replication intermediates carry a single-stranded primosome-assembly site, we hypothesize that the biological role of the replication arrest is to limit the region replicated by Pol I and to promote the replacement of Pol I by the replisome in order to initiate concerted synthesis of the leading and lagging strands.

Bacillus subtilis↗
PubMed1996

In vivo analysis of the plasmid pAM beta 1 resolution system.

The promiscuous plasmid pAM beta 1 from Gram-positive bacteria encodes a resolution system which differs from that of Tn3 in that (i) it requires a histone-like protein and an unusual resolvase-DNA interaction to promote recombination and (ii) it mediates in vivo DNA inversion in plasmid substrates. In this in vivo analysis, the pAM beta 1 resolution site is narrowed down to a 99 bp segment, the strand exchange is mapped within 10 bp and the serine residue at position 10 of the resolvase is shown to be essential for enzyme activity. In addition, data showing that the resolution system does not promote DNA inversion in the Bacillus subtilis chromosome are presented. Implications of this observation are discussed.

Bacillus subtilis↗
PubMed1991

Establishing ownership of the hospital bill in admissions: a key to protecting your facility's fiscal integrity.

You have a plan and you have educated and documented that the patient is cognizant of his/her responsibility. Reality often dictates that problems surface after discharge. How can we prevent the patient from placing the bill on a shelf and forgetting it? As a part of your hospital's bottomline, you have a responsibility to ensure that its fiscal integrity is protected. Afterall, your hospital is also a business as well as a healing institution. Taking the lead in getting the right information at the admission or precertification stage is a vital element in the collection loop. Second, realize that not all, but a majority of patients, are beginning to investigate their benefits and coverage limitations. They may be doing so without a total understanding of insurance terminology or the difference in how much of the hospital/physician charges are paid or what percent rests with them. Last, in Pennsylvania at least, the state requires active participation by hospitals in healthcare cost containment by requiring submission rate and medical outcome information. Why not take this opportunity as an admitting professional to try some of the strategies mentioned. Informing the patient of their insurance benefits and providing an estimate of the bill will increase your department's contribution, and educate the patient about "consumerism". Consumerism is developing within the healthcare industry.(ABSTRACT TRUNCATED AT 250 WORDS)

Admitting Department, Hospital↗