2008 Niday Perinatal Database quality audit: report of a quality assurance project.

INTRODUCTION: This quality assurance project was designed to determine the reliability, completeness and comprehensiveness of the data entered into Niday Perinatal Database. METHODS: Quality of the data was measured by comparing data re-abstracted from the patient record to the original data entered into the Niday Perinatal Database. A representative sample of hospitals in Ontario was selected and a random sample of 100 linked mother and newborn charts were audited for each site. A subset of 33 variables (representing 96 data fields) from the Niday dataset was chosen for re-abstraction. RESULTS: Of the data fields for which Cohen's kappa statistic or intraclass correlation coefficient (ICC) was calculated, 44% showed substantial or almost perfect agreement (beyond chance). However, about 17% showed less than 95% agreement and a kappa or ICC value of less than 60% indicating only slight, fair or moderate agreement (beyond chance). DISCUSSION: Recommendations to improve the quality of these data fields are presented.

Metastatic gestational trophoblastic tumour presenting as spontaneous subcapsular renal haematoma.

We describe a rare case of metastatic choriocarcinoma, which presented with acute left loin pain due to a subcapsular haematoma secondary to a bleeding renal metastasis. The renal metastasis was embolised to prevent further bleeding. To our knowledge, presentation of gestational trophoblastic tumour (GTT) with such symptoms has not been described in the recent literature. Our case illustrates that, although rare, non-gynaecological symptoms can be the first presentation of metastatic choriocarcinoma in the appropriate clinical settings. It also demonstrates that the acute bleed from a renal metastasis can be effectively managed by embolisation.

Long-term retrievability of IVC filters: should we abandon permanent devices?

Thromboembolic disease produces a considerable disease burden, with death from pulmonary embolism in the UK alone estimated at 30,000-40,000 per year. Whilst it is unproven whether filters actually improve longevity, the morbidity and mortality associated with thromboembolic disease in the presence of contraindications to anticoagulation is high. Thus complications associated with filter insertion, and whilst they remain in situ, must be balanced against the alternatives. Permanent filters remain in situ for the remainder of the patient's life and any complications from the filters are of significant concern. Filters that are not permanent are therefore attractive in these circumstances. Retrievable filters, to avoid or decrease long-term filter complications, appear to be a significant advance in the prevention of pulmonary embolism. In this review, we discuss the safety and effectiveness of both permanent and retrievable filters as well as the retrievability of retrievable inferior vena cava (IVC) filters, to explore whether the use of permanent IVC filters can be abandoned in favor of retrievable filters. Currently four types of retrievable filters are available: the Recovery filter (Bard Peripheral Vascular, Tempe, AZ, USA), the Günther Tulip filter (Cook, Bloomington, IN, USA), the OptEase Filter (Cordis, Roden, The Netherlands), and the ALN filter (ALN Implants Chirurgicaux, Ghisonaccia, France). Efficacy and safety data for retrievable filters are as yet based on small series, with a total number of fewer than 1,000 insertions, and follow-up is mostly short term. Current long-term data are poor and insufficient to warrant the long-term implantation of these devices into humans. The case of fractured wire from a Recovery filter that migrated to the heart causing pericardial tamponade requiring open heart surgery is a reminder that any new endovascular device remaining in situ in the long term may produce unexpected problems. We should also bear in mind that the data on permanent filters are much more robust, with reports on over 9,500 cases with follow-up of up to 8 years. The original implantation time of 10-14 days has been extended to more than 100 days as the mean implantation time with some of the filter types. Follow-up (preferably prospective) is necessary for all retrievable filters, whether or not they are retrieved. Until these data become available we should restrict ourselves to the present indications of permanent and retrievable filters. If long-term follow-up data on larger numbers of cases confirm the initial data that retrievable filters are as safe and effective as permanent filters, the use of the retrievable filters is likely to expand.

PROactive 06: cost-effectiveness of pioglitazone in Type 2 diabetes in the UK.

AIMS: To determine the cost-effectiveness of adding pioglitazone to existing treatment regimens in patients with Type 2 diabetes with a history of macrovascular disease who are at high risk of further cardiovascular events. METHODS: We conducted two analyses. A within-trial cost-effectiveness analysis (CEA) based on data from the PROspective pioglitAzone Clinical Trial In macroVascular Events (PROactive) Study was performed to estimate the impact of additional pioglitazone treatment on life expectancy, quality-adjusted life expectancy (QALE) and macrovascular events. PROactive data was then used as a basis for a lifetime modelling analysis using a modified version of the validated CORE diabetes model that simulated the same outcomes over a 35-year time horizon. We accounted for direct medical costs from a health-care payer perspective and related these to the clinical outcomes from the study. Costs and benefits were discounted at 3.5% per annum and extensive sensitivity analyses were performed to account for uncertainty in input parameters. RESULTS: (i) Within-trial CEA: compared with placebo, pioglitazone was associated with improved life expectancy (undiscounted 0.0109 years), increased QALE [0.0190 quality-adjusted life years (QALYs)] and slightly higher costs ( pounds 102 per patient). After a mean treatment period of 3 years, the incremental cost-effectiveness ratio (ICER) of pioglitazone vs. placebo was pounds 5396 per QALY gained. The ICERs were relatively insensitive to cost and utility values and were most sensitive to event rates in the pioglitazone arm. (ii) Long-term CEA: pioglitazone was associated with improvements in clinical outcomes based on model projections beyond the PROactive Study. Patients treated with pioglitazone could expect improved life expectancy (undiscounted 0.406 years), increased QALE (0.152 QALYs) and higher costs of care ( pounds 619 per patient) compared with those on existing treatment alone. The base case analysis indicated that the ICER of pioglitazone vs. placebo was pounds 4060 per QALY gained. The cost-effectiveness acceptability curve showed there was an 84.3% likelihood that pioglitazone would be considered cost-effective in the UK using a willingness-to-pay threshold of pounds 30 000 per QALY gained. These long-term results were most sensitive to variation in the time horizon, the duration of cardiovascular benefit of pioglitazone, and changes in mortality rates. CONCLUSIONS: The addition of pioglitazone to existing therapy in patients with Type 2 diabetes at high risk of further cardiovascular events is cost-effective and represents good value for money by currently accepted standards in the UK.

The impact of clinical audit on antibiotic prescribing in general dental practice.

OBJECTIVE: To reduce the number of antibiotics inappropriately prescribed by general dental practitioners, and to increase overall prescription accuracy. DESIGN: A prospective clinical audit carried out between September and March of 2002-3 and 2003-4. SETTING: General dental practices in Eastern England. SUBJECTS AND METHODS: The pre-audit antibiotic prescribing practices of 212 general dental practitioners were recorded over an initial six week period. On each occasion this included which antibiotic had been chosen, together with its dose, frequency and duration, as well as the clinical condition and reason for which the prescription had been raised. When related to prophylaxis, the patient's medical history was also noted. Following education on contemporary prescribing guidelines, presentations which illustrated the practitioners' previous errors, and the agreement of standards to be achieved, the process was repeated for another six weeks, and the results compared. RESULTS: In the pre-audit period, 2,951 antibiotic prescriptions were issued, and during the audit this was reduced by 43.6% to 1,665. The majority were for therapeutic reasons, with only 10.5% and 13.6% for medical prophylaxis during the pre-audit and audit periods respectively. Over both periods, amoxicillin and metronidazole were the two most commonly prescribed antimicrobials (63.4% and 21.2% respectively). In the pre-audit period, only 43% of all prescriptions were error free in dose, frequency, and/or duration of use, but this rose significantly to 78% during the audit. Equally, using contemporary published guidelines, out of all the prescriptions made in the pre-audit period, only 29.2% were deemed to be justified, as compared to 48.5% during the audit. CONCLUSIONS: Clinical audit, in conjunction with education, and prescribing guidelines can favourably change antibiotic prescribing patterns among general dental practitioners.

Endovascular embolization of visceral artery aneurysms with ethylene-vinyl alcohol (Onyx): a case series.

We report the application of the liquid embolic agent ethylene-vinyl alcohol (Onyx; MicroTherapeutics, Irvine, CA, USA) in the management of visceral artery aneurysms. The technique and indications for using Onyx are discussed with emphasis on the management of wide-necked aneurysms and maintenance of patency of the parent vessel. None of the cases was considered suitable for stent-grafting or embolization with conventional agents. Two aneurysms of the renal artery bifurcation and one aneurysm of the inferior pancreaticoduodenal artery were treated. Following treatment there was complete exclusion of all aneurysms. There was no evidence of end-organ infarction. Follow-up with intervals up to 6 months has shown sustained aneurysm exclusion. Onyx is known to be effective in the management of intracranial aneurysms. Our experience demonstrates the efficacy and applicability of the use of Onyx in the treatment of complex visceral artery aneurysms.

GAP1IP4BP contains a novel group I pleckstrin homology domain that directs constitutive plasma membrane association.

The group I family of pleckstrin homology (PH) domains are characterized by their inherent ability to specifically bind phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) and its corresponding inositol head-group inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P(4)). In vivo this interaction results in the regulated plasma membrane recruitment of cytosolic group I PH domain-containing proteins following agonist-stimulated PtdIns(3,4,5)P(3) production. Among group I PH domain-containing proteins, the Ras GTPase-activating protein GAP1(IP4BP) is unique in being constitutively associated with the plasma membrane. Here we show that, although the GAP1(IP4BP) PH domain interacts with PtdIns(3,4, 5)P(3), it also binds, with a comparable affinity, phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)) (K(d) values of 0.5 +/- 0.2 and 0.8 +/- 0.5 microm, respectively). Intriguingly, whereas this binding site overlaps with that for Ins(1,3,4,5)P(4), consistent with the constitutive plasma membrane association of GAP1(IP4BP) resulting from its PH domain-binding PtdIns(4,5)P(2), we show that in vivo depletion of PtdIns(4,5)P(2), but not PtdIns(3,4,5)P(3), results in dissociation of GAP1(IP4BP) from this membrane. Thus, the Ins(1,3,4,5)P(4)-binding PH domain from GAP1(IP4BP) defines a novel class of group I PH domains that constitutively targets the protein to the plasma membrane and may allow GAP1(IP4BP) to be regulated in vivo by Ins(1,3,4,5)P(4) rather than PtdIns(3,4,5)P(3).

Molecular modelling and site-directed mutagenesis of the inositol 1,3,4,5-tetrakisphosphate-binding pleckstrin homology domain from the Ras GTPase-activating protein GAP1IP4BP.

GAP1(IP4BP) is a Ras GTPase-activating protein (GAP) that in vitro is regulated by the cytosolic second messenger inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P(4)]. We have studied Ins(1,3,4,5)P(4) binding to GAP1(IP4BP), and shown that the inositol phosphate specificity and binding affinity are similar to Ins(1,3,4,5)P(4) binding to Bruton's tyrosine kinase (Btk), evidence which suggests a similar mechanism for Ins(1,3,4,5)P(4) binding. The crystal structure of the Btk pleckstrin homology (PH) domain in complex with Ins(1,3,4,5)P(4) has shown that the binding site is located in a partially buried pocket between the beta 1/beta 2- and beta 3/beta 4-loops. Many of the residues involved in the binding are conserved in GAP1(IP4BP). Therefore we generated a model of the PH domain of GAP1(IP4BP) in complex with Ins(1,3,4,5)P(4) based on the Btk-Ins(1,3,4,5)P(4) complex crystal structure. This model had the typical PH domain fold, with the proposed binding site modelling well on the Btk structure. The model has been verified by site-directed mutagenesis of various residues in and around the proposed binding site. These mutations have markedly reduced affinity for Ins(1,3,4,5)P(4), indicating a specific and tight fit for the substrate. The model can also be used to explain the specificity of inositol phosphate binding.

Equilibrium and kinetic studies of substrate binding to 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase from Escherichia coli.

6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes the pyrophosphorylation of 6-hydroxymethyl-7,8-dihydropterin (HMDP) by ATP to form 6-hydroxymethyl-7,8-dihydropterin pyrophosphate, an intermediate in the pathway for folic acid biosynthesis. The enzyme has been identified as a potential target for antimicrobial drugs. Equilibrium binding studies showed that Escherichia coli HPPK-bound ATP or the nonhydrolyzable ATP analogue alpha, beta-methyleneadenosine triphosphate (AMPCPP) with high affinity. The fluorescent ATP analogue 2'(3')-O-(N-methylanthraniloyl) adenosine 5'-triphosphate (MANT-ATP) exhibited a substantial fluorescence enhancement upon binding to HPPK, with an equilibrium dissociation constant comparable with that for ATP (10.4 and 4.5 micrometer, respectively). The apoenzyme did not bind the second substrate HMDP, however, unless AMPCPP was present, suggesting that the enzyme binds ATP first, followed by HMDP. Equilibrium titration of HPPK into HMDP and AMPCPP showed an enhancement of fluorescence from the pterin ring of the substrate, and a dissociation constant of 36 nm was deduced for HMDP binding to the HPPK.AMPCPP binary complex. Stopped flow fluorimetry measurements showed that the rate constants for the binding of MANT-ATP and AMPCPP to HPPK were relatively slow (3.9 x 10(5) and 1.05 x 10(5) m(-1) s(-1), respectively) compared with the on rate for binding of HMDP to the HPPK.AMPCPP binary complex. The significance of these results with respect to the crystal structures of HPPK is discussed.

Health-related quality of life in type 2 diabetes (TARDIS-2).

BACKGROUND: Type 2 diabetes is now recognized as a major public health concern but its burden on society is under-researched. METHODS: T(2)ARDIS was a postal survey of 1578 people with type 2 diabetes across four UK centres, incorporating measures of resource use, treatment satisfaction and health-related quality of life (HrQoL). The findings included data on the EQ-5D that enabled the HrQoL burden of the disease to be established by comparison with equivalent data for the general population and the diabetic population as a whole from the 1996 Health Survey of England. RESULTS: The results indicate a significant deficit experienced by people with type 2 diabetes vs. their age group peers in the general population. The proportion of T(2)ARDIS respondents reporting problems increases in relation to the presence of complications, and microvascular complications appear to have more impact than macrovascular complications. CONCLUSIONS: This confirms the need for treatment policies to focus on reducing the risk of such complications and hence improve patients' HrQoL.

Structural and functional analysis of the putative inositol 1,3,4, 5-tetrakisphosphate receptors GAP1(IP4BP) and GAP1(m).

Previously we have purified and cloned a high affinity isomerically specific inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4)-binding protein which, because it is clearly a member of the GAP1 family of Ras GTPase-activating proteins (GAP), we have termed GAP1(IP4BP). Here we show that expressed full-length GAP1(IP4BP) binds Ins(1,3,4, 5)P4 with an affinity and specificity similar to that of the originally purified protein, a binding activity which is dependent on a functional PH/Btk domain. Furthermore, we highlight a fundamental distinction between GAP1(IP4BP) and its homologue GAP1(m), namely that both proteins function as Ras GAPs but only GAP1(IP4BP) displays Rap GAP activity.

Modulation of Ins(2,4,5)P3-stimulated Ca2+ mobilization by ins(1,3,4, 5)P4: enhancement by activated G-proteins, and evidence for the involvement of a GAP1 protein, a putative Ins(1,3,4,5)P4 receptor.

We have previously shown that addition of Ins(1,3,4,5)P4 to permeabilized L1210 cells increases the amount of Ca2+ mobilized by a submaximal concentration of Ins(2,4,5)P3, and we suggested that, in doing this, Ins(1,3,4,5)P4 is not working via an InsP3 receptor but indirectly via an InsP4 receptor [Loomis-Husselbee, Cullen, Dreikhausen, Irvine and Dawson (1996) Biochem. J. 314, 811-816]. Here we have investigated whether this effect might be mediated by GAP1(IP4BP), recently identified as a putative receptor for Ins(1,3, 4,5)P4. GAP1(IP4BP) is a protein that interacts with one or more monomeric G-proteins, so we sought evidence for involvement of monomeric G-proteins in the effects of Ins(1,3,4,5)P4 in permeabilized L1210 cells. Guanosine 5'-[gamma-thio]triphosphate (GTP[S]) enhanced the effect of Ins(1,3,4,5)P4 on Ins(2,4, 5)P3-stimulated Ca2+ mobilization, but had no effect on the action of Ins(2,4,5)P3 alone. A specific enhancement of only the action of Ins(1,3,4,5)P4 was also seen with GTP[S]-loaded R-Ras or Rap1a (two G-proteins known to interact with GAP1(IP4BP)), whereas H-Ras was inactive at similar concentrations. Guanosine 5'-[beta-thio]diphosphate (GDP[S]) did not alter the action of either Ins(2,4,5)P3 or Ins(1,3,4,5)P4. Finally, the addition of exogenous GAP1(IP4BP), purified from platelets, markedly enhanced the effect of Ins(1,3,4,5)P4, and again, the amount of Ca2+ mobilized by Ins(2,4,5)P3 alone was unaltered. We conclude that the increase in Ins(2,4,5)P3-stimulated Ca2+ mobilization by Ins(1,3,4, 5)P4 may be mediated by GAP1(IP4BP) or a closely related protein (such as GAP1(m)), and if so, the action of the GAP1 is not solely to regulate GTP loading of a G-protein, but rather it acts with a G-protein to cause its effect.

Distinct subcellular localisations of the putative inositol 1,3,4,5-tetrakisphosphate receptors GAP1IP4BP and GAP1m result from the GAP1IP4BP PH domain directing plasma membrane targeting.

Inositol 1,3,4,5-tetrakisphosphate (IP4), is a ubiquitous inositol phosphate that has been suggested to function as a second messenger. Recently, we purified and cloned a putative IP4 receptor, termed GAP1(IP4BP)[1], which is also a member of the GAP1 family of GTPase-activating proteins for the Ras family of GTPases. A homologue of GAP1(IP4BP), called GAP1(m), has been identified [2] and here we describe the cloning of a GAP1(m) cDNA from a human circulating-blood cDNA library. We found that a deletion mutant of GAP1(m), in which the putative phospholipid-binding domains (C2A and C2B) have been removed, binds to IP4 with a similar affinity and specificity to that of the corresponding GAP1(IP4BP) mutant. Expression studies of the proteins in either COS-7 or HeLa cells showed that, whereas GAP1(IP4BP) is located solely at the plasma membrane, GAP1(m) seems to have a distinct perinuclear localisation. By mutational analysis, we have shown that the contrast in subcellular distribution of these two closely related proteins may be a function of their respective pleckstrin homology (PH) domains. This difference in localisation has fundamental significance for our understanding of the second messenger functions of IP4.

Conformational changes and the role of metals in the mechanism of type II dehydroquinase from Aspergillus nidulans.

We have investigated the involvement of metal ions and conformational changes in the elimination reaction catalysed by type II dehydroquinase from Aspergillus nidulans. Mechanistic comparisons between dehydroquinases and aldolases raised the possibility that, by analogy with type II aldolases, type II dehydroquinases may require bivalent metal ions for activity. This hypothesis was tested by a combination of metal analysis, effects of metal chelators and denaturation/renaturation experiments, all of which failed to show any evidence that type II dehydroquinases are metal-dependent dehydratases. Analysis of native and refolded enzyme by electron microscopy showed that the dodecameric type II enzyme from A. nidulans adopts a ring-like structure similar to that of glutamine synthase, suggesting an arrangement of two hexameric rings stacked on top of one another. Evidence for a ligand-induced conformational change came from both chemical modification and proteolysis experiments. Inactivation data with the arginine-specific reagent phenylglyoxal indicated that, at pH 7.5, two arginine residues are modified: one modification displays affinity-labelling kinetics and has a 1:1 stoichiometry, while the other displays simple bimolecular kinetics and a stoichiometry of 2:1. The labelling at the affinity site is markedly enhanced by the addition of ligand, implying that this active-site residue is further exposed to modification by phenylglyoxal as a result of a ligand-induced conformational change. A combination of proteolysis and electrospray MS experiments identified the site of affinity labelling as Arg-19. The highly conserved N-terminal region encompassing Arg-19 of type II dehydroquinase was found to be particularly susceptible to proteolytic cleavage Limited digestion with proteinase K inactivates the enzyme, although the type II oligomeric structure is retained, and ligand binding partially protects against this inactivation.

Cloning, sequencing, expression, purification and preliminary characterization of a type II dehydroquinase from Helicobacter pylori.

A heat-stable dehydroquinase was purified to near homogeneity from a plate-grown suspension of the Gram-negative stomach pathogen Helicobacter pylori, and shown from both its subunit and native molecular masses to be a member of the type II family of dehydroquinases. This was confirmed by N-terminal amino acid sequence data. The gene encoding this activity was isolated following initial identification, by random sequencing of the H. pylori genome, of a 96 bp fragment, the translated sequence of which showed strong identity to a C-terminal region of other type II enzymes. Southern blot analysis of a cosmid library identified several potential clones, one of which complemented an Escherichia coli aroD point mutant strain deficient in host dehydroquinase. The gene encoding the H. pylori type II dehydroquinase (designated aroQ) was sequenced. The translated sequence was identical to the N-terminal sequence obtained directly from the purified protein, and showed strong identity to other members of the type II family of dehydroquinases. The enzyme was readily expressed in E. coli from a plasmid construct from which several milligrams of protein could be isolated, and the molecular mass of the protein was confirmed by electrospray MS. The aroQ gene in H. pylori may function in the central biosynthetic shikimate pathway of this bacterium, thus opening the way for the construction of attenuated strains as potential vaccines as well as offering a new target for selective enzyme inhibition.

Dentofacial form in the five-year-old child with unilateral cleft lip and palate.

It is generally believed that studies of outcome for children with clefts of the lip and palate should be based on patients who are in their teens. This means that health care workers who look after these children would have to wait many years until the quality of treatment could be evaluated. In this study, significant differences between two centers, Oslo and Manchester, in facial form at the age of 5 years were detected. Based on cephalometric analysis, children from Manchester were more likely to have a retrognathic maxilla with the upper lip significantly behind the esthetic plane. An important future step may be the setting up of "reference centers" with a large archive of database information for each racial group. This would assist smaller centers in comparing their outcomes.

Dyspepsia in England and Scotland.

A validated postal questionnaire has been used to establish the prevalence of dyspeptic symptoms in five geographical locations from the south coast of England to the north of Scotland. The six month period prevalence of dyspepsia in the 7428 respondents to the questionnaire is 41% and equal between the sexes, with similar prevalence rates in the centres studied. There is considerable overlap between upper abdominal symptoms and symptoms of heartburn; 56% of patients with dyspepsia experience both groups of symptoms. Symptom frequency falls progressively with age in men and women, but the proportion of people seeking medical advice for dyspepsia rises with age. One quarter of the dyspeptic patients studied have consulted a general practitioner about their symptoms. This study suggests that the prevalence of dyspepsia in the community has changed little over the last 30 years, despite evidence that the frequency of peptic ulcer disease is falling. Symptom prevalence is unrelated to social class, but this factor is associated with consultation behaviour, the consultation rate rising from 17% in social class 1 to 29% in social class 4. The use of investigations--barium meal and endoscopy--is similarly related to social class; the lowest rate for ulcer diagnosis (4.7%) is found in social class 1 and the highest (17.1%) in social class 5.

The dimensional stability of self-disinfecting alginate impressions compared to various immersion regimes.

Alginate impressions of a master acrylic study model pair were made in order to assess the effect of various disinfection techniques on dimensional stability. Impressions were made using self-disinfecting alginate, traditional alginate which had been dipped or soaked in a disinfecting solution, and included was a control group which was not disinfected. Inter- and intra-arch linear measurements of the resultant study casts were made using a Reflex Metrograph. The small differences found for the variables measured were not statistically significant.