Cost-effectiveness of endovascular abdominal aortic aneurysm repair

Background

The rapid introduction of endovascular abdominal aortic aneurysm repair (EVAR) has considerable implications for the management of abdominal aortic aneurysm (AAA). This study was undertaken to determine an optimal strategy for the use of EVAR based on the best currently available evidence.

Methods

Economic modelling and probabilistic sensitivity analysis considered reference cases representing a fit 70-year-old with a 5·5-cm diameter AAA (RC1) and an 80-year-old with a 6·5-cm AAA unfit for open surgery (RC2). Results were assessed as incremental cost-effectiveness ratio (ICER) compared with open repair (RC1) or conservative management (RC2).

Results

In RC1 EVAR produced a gain of 0·10 quality-adjusted life years (QALYs) for an estimated cost of £11 449, giving an ICER of £110 000 per QALY. EVAR consistently had an ICER above £30 000 per QALY over a range of sensitivity analyses and alternative scenarios. In RC2 EVAR produced an estimated benefit of 1·64 QALYs for an incremental cost of £14 077 giving an incremental cost per QALY of £8579.

Conclusion

It is unlikely that EVAR for fit patients suitable for open repair is within the commonly accepted range of cost-effectiveness for a new technology. For those unfit for conventional open repair it is likely to be a cost-effective alternative to non-operative management. Sensitivity analysis suggests that research efforts should concentrate on determining accurate rates for late complications and reintervention, particularly in patients with high operative risks.

Results from the Prospective Registry of Endovascular Treatment of Abdominal Aortic Aneurysms (RETA): Mid Term Results to Five Years

OBJECTIVES

To assess the mid-term outcomes up to 5 years following endovascular repair of abdominal aortic aneurysms (EVAR), following its initial introduction into practice in the UK.

DESIGN

A prospective voluntary Registry of Endovascular Treatment of Aneurysms (RETA) collected demographic and risk factor data, short term (30 day) outcomes and follow up outcomes up to 5 years from the 41 centres that initially undertook EVAR in the UK.

RESULTS

Short term outcomes (30 days): 90.4% of aneurysms were successfully excluded, 6.1% had persistent endoleaks and 5.8% of patients had died. Follow up was obtained from 30 days up to 5 years (mean 3.1 years). Returns rates for requested follow up data were 87% at 1 year and 77, 65, 52 and 51% at 2, 3, 4 and 5 years, respectively. Ninety percent of deaths at follow up were unrelated to the stent-graft or aneurysm. Persistent proximal type I endoleak was associated with significant mortality both from attempted open repair or from rupture if untreated. Other endoleaks were more benign. Complications related to the aneurysm or device occurred at an average rate of 15% per annum. The most common complications were secondary endoleaks or graft migration. Endovascular treatment was preferred if treatment was necessary for graft complications. The cumulative freedom from secondary procedure (Kaplan-Meier) were 87, 77, 70, 65 and 62% at 1, 2, 3, 4 and 5 years of follow up, respectively.

CONCLUSIONS

Registry data provides useful information to guide the design of more formal trials. Collecting follow up from voluntarily submitted data is difficult. The registry data remains well ahead of the trial data, but indicate that long term follow up is required in these trials, because of the high rate of complications seen at follow up.

Ultrasound for central venous cannulation: economic evaluation of cost-effectiveness

We compared the economics of using two-dimensional ultrasound locating devices and more traditional landmark methods for central venous cannulation in the National Health Service (NHS). The evaluation consisted of a systematic review of randomised controlled trials and an economic evaluation using decision analytic cost-effectiveness modelling. Incremental costs per complication avoided associated with landmark and ultrasound central venous cannulation were modelled for patients scheduled for central venous cannulation. The marginal economic cost of using ultrasound for central venous cannulation was less than 10 pounds sterling per procedure, assuming that a machine is used for 15 procedures each week. The base case scenario implied that 2000 pounds sterling worth of resource savings result for every 1000 procedures undertaken and 90 avoided complications. Sensitivity analysis indicated that the results of modelling appear robust to the central assumptions used. Ultrasound guidance used in central venous cannulation procedures saves NHS resources even with conservative modelling assumptions.

Physiological characterization of Mycobacterium sp. strain 1B isolated from a bacterial culture able to degrade high-molecular-weight polycyclic aromatic hydrocarbons

AIM

The aim of this study was to further characterize a bacterial culture (VUN 10,010) capable of benzo[a]pyrene cometabolism.

METHODS AND RESULTS

The bacterial culture, previously characterized as a pure culture of Stenotrophomonas maltophilia (VUN 10,010), was found to also contain another bacterial species (Mycobacterium sp. strain 1B), capable of degrading a similar range of PAH substrates. Analysis of its 16S rRNA gene sequence and growth characteristics revealed the strain to be a fast-growing Mycobacterium sp., closely related to other previously isolated PAH and xenobiotic-degrading mycobacterial strains. Comparison of the PAH-degrading characteristics of Mycobacterium sp. strain 1B with those of S. maltophilia indicated some similarities (ability to degrade phenanthrene and pyrene), but some differences were also noted (S. maltophilia able to degrade fluorene, but not fluoranthene, whereas Mycobacterium sp. strain 1B can degrade fluoranthene, but not fluorene). Unlike the S. maltophilia culture, there was no evidence of benzo[a]pyrene degradation by Mycobacterium sp. strain 1B, even in the presence of other PAHs (ie pyrene) as co-metabolic substrates. Growth of Mycobacterium sp. strain 1B on other organic carbon sources was also limited compared with the S. maltophilia culture.

CONCLUSIONS

This study isolated a Mycobacterium strain from a bacterial culture capable of benzo[a]pyrene cometabolism. The Mycobacterium strain displays different PAH-degrading characteristics to those described previously for the PAH-degrading bacterial culture. It is unclear what role the two bacterial strains play in benzo[a]pyrene cometabolism, as the Mycobacterium strain does not appear to have endogenous benzo[a]pyrene degrading ability.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study describes the isolation and characterization of a novel PAH-degrading Mycobacterium strain from a PAH-degrading culture. Further studies utilizing this strain alone, and in combination with other members of the consortium, will provide insight into the diverse roles different bacteria may play in PAH degradation in mixed cultures and in the environment.

Gene expression in Escherichia coli biofilms

DNA microarrays were used to study the gene expression profile of Escherichia coli JM109 and K12 biofilms. Both glass wool in shake flasks and mild steel 1010 plates in continuous reactors were used to create the biofilms. For the biofilms grown on glass wool, 22 genes were induced significantly (p< or =0.05) compared to suspension cells, including several genes for the stress response ( hslS, hslT, hha, and soxS), type I fimbriae ( fimG), metabolism ( metK), and 11 genes of unknown function ( ybaJ, ychM, yefM, ygfA, b1060, b1112, b2377, b3022, b1373, b1601, and b0836). The DNA microarray results were corroborated with RNA dot blotting. For the biofilm grown on mild steel plates, the DNA microarray data showed that, at a specific growth rate of 0.05/h, the mature biofilm after 5 days in the continuous reactors did not exhibit differential gene expression compared to suspension cells although genes were induced at 0.03/h. The present study suggests that biofilm gene expression is strongly associated with environmental conditions and that stress genes are involved in E. coli JM109 biofilm formation.

The economics of integrated electronic medical record systems

The decision to adopt electronic medical record systems in private practices is usually based on factors specific to the practice--the cost, cost and timesaving, and impact on quality of care. As evident by the low adoption rates, providers have not found these evaluations compelling. However, it is recognized that the widespread adoption of EMR systems would greatly benefit the health care system as a whole. One explanation for the lack of adoption is that there is a misalignment of the costs and benefits of EMR systems across the health care system. In this paper we present an economic model of the adoption of EMR systems that explicitly represents the distribution of costs and benefits across stakeholders (physicians, hospitals, insurers, etc.). We discuss incentive systems for balancing the costs and benefits and, thus, promoting the faster adoption of EMR systems. Finally, we describe our plan to extend the model and to use real-world data to evaluate our model.

Point mutations in the pfcrt and pfmdr-1 genes of Plasmodium falciparum and clinical response to chloroquine, among malaria patients from Nigeria

Chloroquine (CQ) resistance in Plasmodium falciparum has been associated with specific point mutations in the pfcrt and pfmdr-1 genes. In the present study, 30 children aged 1-12 years, who were all suffering from acute, uncomplicated, P. falciparum malaria in Ibadan, Nigeria, were evaluated to assess the association between these mutations and clinical outcome following treatment with CQ. The parasites, in blood samples collected pre-treatment and, in those who failed treatment, on the day symptoms re-occurred post-treatment, were genotyped using the polymorphic MSP1, MSP2 and GLURP loci and PCR-RFLP. The results showed that, pre-treatment, all 30 patients had polyclonal infections, the mean numbers of P. falciparum clones detected per infection being 2.6 with MSP1, 4.2 with MSP2 and 2.8 with GLURP. The T76 allele of pfcrt and the Y86 allele of pfmdr-1 were found in 53% and 40%, respectively, of the pre-treatment samples from the 15 patients who failed CQ treatment, but the Y1246 mutation in pfmdr-1 was never detected. Although the parasites from the two patients with high-grade (RIII) resistance to CQ had both of these point mutations, the presence of the T76 allele of pfcrt or the Y86 allele of pfmdr-1 (considered individually) could not be used to predict treatment outcome. However, a high frequency of clonal multiplicity may confound attempts to associate the point mutations in pfcrt or pfmdr-1 with clinical response to CQ. It remains unclear whether the present results represent the characteristics of the predominant parasite populations in the study area. Further studies are needed before the strength of the association between the point mutations identified as markers of drug resistance and clinical outcome can be accurately evaluated, in this and other regions of intense transmission.

Prevalence of Plasmodium falciparum pfcrt polymorphisms and in vitro chloroquine sensitivity in Senegal

Mutations in pfcrt K76T are associated with chloroquine resistance in Plasmodium falciparum. Previous studies of K76T mutations in Senegal reported the association of T76 with in vitro-resistant isolates, but this mutation was also prevalent in chloroquine-sensitive isolates. This suggests involvement of additional genetic loci in modulating chloroquine resistance. Additional pfcrt polymorphisms at codons A220S, Q271E, N326S and R371I have been found in chloroquine-resistant isolates. We wanted to test if sequential acquisition of mutations at these codons leads to in vitro chloroquine resistance. Stepwise accumulation of mutations was not detected, rather there was almost complete linkage between the pfcrt K76T mutation and polymorphisms in these codons. Therefore these additional polymorphisms do not enhance the correlation between pfcrt T76 and chloroquine resistance in Senegal. These data suggest that in vitro chloroquine resistance requires the genetic background of the pfcrt K76T mutation and additional mutations in genetic loci outside the pfcrt gene.

P38 mitogen-activated protein kinase mediates hexosamine-induced TGFbeta1 mRNA expression in human mesangial cells

AIMS/HYPOTHESIS

The hexosamine pathway has been implicated in the induction of TGFbeta1 expression and in the pathophysiology of diabetic glomerulopathy. Glucose-induced TGFbeta1 expression is mediated by p38 mitogen-activated-protein-kinase (p38-MAPK) and this kinase is activated in the diabetic glomeruli. We examined whether the p38-MAPK is implicated in hexosamine-induced TGFbeta1 mRNA expression in human mesangial cells. GFAT overexpression induced an increase in p38-MAPK activation after 6 and 12 h incubation in normal glucose, and this was prevented by the GFAT inhibitor azaserine. Furthermore, high glucose enhanced p38-MAPK activation in GFAT tranfected cells ( p</=0.04). P38-MAPK inhibition using SB202190 (1 micro mol/l) reduced hexosamine-induced TGFbeta1 expression in normal and high glucose. The activation of the p38-MAPK was dependent on protein kinase-C.

METHODS

The products of the hexosamine biosynthetic pathway were increased by the addition of glucosamine or by the overexpression of the rate-limiting enzyme of the hexosamine pathway, glutamine: fructose-6-phosphate amidotransferase (GFAT).

RESULTS

Glucosamine addition resulted in cell death. UDP-N-Acetylglucosamine, one of the major hexosamine end-products, was increased in normal (7 mmol/l) and high (25 mmol/l) glucose conditions in GFAT-transfected cells compared to control transfected cells by twofold and 1.7-fold respectively ( p</=0.04) and this was accompanied by a 1.6- and 2.3-fold increase ( p</=0.02) in TGFbeta1 mRNA expression. Addition of the GFAT inhibitor azaserine (10 micro mol/l) prevented the induction of TGFbeta1 in GFAT transfected cells.

CONCLUSION/INTERPRETATION

Overexpression of GFAT increases hexosamine accumulation which mediates TGFbeta1 expression via a protein kinase-C and p38-MAPK dependent mechanism. Increased glucose concentrations magnify these effects.

The characteristics of personal order sets in a computerized physician order entry system at a community hospital

Personal order sets (POS) have been touted as important for the success of a computerized physician order entry (CPOE) system. However, POS may systematize practice variability and are difficult to centrally administer. Few studies have looked at the characteristics and use of POS in a community hospital. We examined how POS are used at the Queen's Medical Center (QMC). POS are an important part of the success of the QMC CPOE, but have definite disadvantages.

Registry of endovascular treatment of abdominal aortic aneurysms (RETA): the fate of patients with primary endoleaks

Background

The aim was to present the follow-up data of patients with a primary endoleak identified in the periprocedural period to establish the consequences of these endoleaks.

Methods

There were 123 primary endoleaks in the 1000 operations logged in the Registry of Endovascular Treatment of Abdominal Aortic Aneurysms (RETA) database, visualized either immediately after the procedure or at 30-day computed tomography. The sites of these were: collateral, 42 (34 per cent); proximal anastomotic (PA), 41 (33 per cent); distal anastomotic (DA), 19 (15 per cent); midgraft, 12 (10 per cent); occluder, three (2 per cent); and site not stated in six (5 per cent). The fate of these endoleaks was examined from available follow-up data.

Results

Nine patients (22 per cent) with PA endoleaks died from rupture (n = 3) or following surgery for the endoleak (n = 6). Eleven patients had persistent primary PA endoleak with or without treatment; three of these patients had rupture. Others were treated successfully with surgery, proximal cuffs or angioplasty of the proximal anastomosis. Twenty-two collateral endoleaks (52 per cent) resolved spontaneously at 30 days. There were no ruptures at follow-up. Seven of the 19 DA endoleaks resolved spontaneously by 30 days and four had further endovascular treatment before discharge. Of the eight persistent endoleaks, three resolved spontaneously and three had endovascular treatment. There were no ruptures at follow-up. Two of the three occluder endoleaks resolved spontaneously; the other patient died suddenly from an unknown cause. Nine of the 12 midgraft endoleaks resolved by 30 days, and one had resolved spontaneously at 1 year; again there were no ruptures in this group.

Conclusion

The presence of a PA endoleak justifies an aggressive approach to treatment because of their association with aneurysm rupture. However, open surgical treatments carry a significant mortality rate. Other endoleaks follow a more benign course, and many will resolve spontaneously.

RETA: update on the short-term (30 day) and long-term (1 and 2 years) results of endovascular repair of abdominal aortic aneurysms

Background

The updated results from the Registry of Endovascular Treatment of Aneurysms (RETA) for short- and long term outcomes from 3 years of data collection are presented.

Methods

Some 611 patients were submitted to RETA from January 1996 to December 1999 from 31 centres. In the same period 1-year follow-up was received for 299 of the 340 cases requested (88 per cent return rate) and 2-year follow-up for 88 of the 155 cases requested (57 per cent return rate).

Results

At 30 days 90 per cent of abdominal aortic aneurysms (AAA) were excluded. The rate of conversion to open repair was 5 per cent. Complications occurred in 25 per cent of patients. The overall 30-day mortality rate was 7 per cent with significantly more deaths in the aortouni-iliac and crossover groups (12 versus 4 per cent; adjusted odds ratio (OR) 2·6 (95 per cent confidence interval (c.i.) 1·2–5·9); P = 0·018), in unfit patients (18 versus 4 per cent; adjusted OR 4·3 (95 per cent c.i. 2·0–9·5); P &lt; 0·001) and in patients with larger aneurysms (10 versus 2 per cent; adjusted OR 4·4 (95 per cent c.i. 1·4–13); P = 0·009). At 1 year the mortality rate was 11 per cent, with four deaths (1 per cent) due to ruptured AAA. New complications were reported in 53 patients (20 per cent) with 31 (12 per cent) related to the device or AAA. In the second year of follow-up the mortality rate was 11 per cent with one death (1 per cent) due to ruptured AAA. New complications in the second year after device placement were reported in 24 per cent of patients, with 16 (20 per cent) related to the device or AAA. The cumulative endoleak-free survival for all patients was 57 per cent at 2 years.

Conclusion

The 30-day mortality rate for endovascular repair was comparable to reported results for conventional surgery, particularly in fit patients. There was a relatively high complication rate at follow-up, with ruptures reported. Most complications had endovascular treatment.

Midterm follow-up of 1000 patients in the Registry of Endovascular Treatment of Abdominal Aortic Aneurysms (RETA)

Background

The aim was to present the midterm follow-up data of patients in the Registry of Endovascular Treatment of Abdominal Aortic Aneurysms (RETA).

Methods

RETA now has a cohort of 1000 registered patients. Follow-up data are available for 483 patients at 1 year (80·8 per cent follow-up rate), 191 at 2 years (78·0 per cent follow-up rate) and 64 at 3 years (64·0 per cent follow-up rate).

Results

The mortality rates were 10·8, 12·6 and 6·3 per cent at 1, 2 and 3 years' follow-up respectively. The majority of deaths at follow-up were unrelated to the endovascular aneurysm repair. However, ruptures have occurred, with five (1·0 per cent) occurring in the first year of follow-up and three (1·6 per cent) reported in the second year of follow-up. This gives a cumulative risk of rupture of 1·0 per cent at 1 year and 2·6 per cent at 2 and 3 years. Three of the ruptures had persisting primary proximal endoleaks and two had documented secondary endoleaks. Complications related to the aneurysm or device occurred in 11·1, 14·8 and 12·8 per cent of cases at 1, 2 and 3 years' follow-up. The commonest problems were secondary endoleaks, although most of these had successful endovascular treatment. Graft or limb occlusions were the next most common problems. Follow-up of patients having secondary procedures with endovascular treatment suggests these treatments are durable, although the numbers at present are small. The cumulative endoleak-free survival rate was 73·4, 57·9 and 49·9 per cent, and the cumulative freedom from endoleak rate was 88·3, 81·2 and 75·6 per cent at 1, 2 and 3 years' follow-up respectively.

Conclusion

Most deaths occurring at follow-up are not related to the aortic aneursyms. Ruptures have occurred, some related to primary proximal type I endoleaks. Others may be related to secondary endoleaks that have not been detected. Late complications related to the device or aneurysm occur at a rate of about 10 per cent per year. Most frequently these are new endoleaks and are amenable to endovascular treatment, but recurrence may occur, so continued surveillance is necessary.

Biological conversion of cyclic alkanes and cyclic alcohols into dicarboxylic acids: biochemical and molecular basis

Biological oxidation of cyclic alkanes and cyclic alcohols normally results in formation of the corresponding dicarboxylic acids, which are further metabolized in the cell. The biochemical pathways for oxidative conversion of cyclic compounds are similar in various phylogenetically diverse bacteria. Significant progress has been made in the past 2 years in the isolation and characterization of genes involved in cyclic alkane oxidation pathways in several bacterial species. In this article, we review recent advancements in the field of cyclic alcohol oxidation with focus on the biochemical and genetic characterization of the gene functions. Phylogenetic relationships of the analogous enzymes in the pathways are analyzed. Potential biocatalysis applications of these enzymes are also discussed.

Pure bacterial isolates that convert p-xylene to terephthalic acid

Bacteria that grow on p-xylene, p-toluic acid, and terephthalic acid (TPA) were isolated from a wastewater bioreactor that is used to treat a waste stream that contains all three of these compounds. Although previously described aerobic bacteria degrade p-xylene by initially oxidizing a single methyl group to form p-toluic acid and then cleaving the aromatic ring, some of the bacteria isolated during this study transformed p-xylene by oxidizing both methyl groups to produce TPA.

A successful technique for removing names in pathology reports using an augmented search and replace method

The ability to access large amounts of de-identified clinical data would facilitate epidemiologic and retrospective research. Previously described de-identification methods require knowledge of natural language processing or have not been made available to the public. We take advantage of the fact that the vast majority of proper names in pathology reports occur in pairs. In rare cases where one proper name is by itself, it is preceded or followed by an affix that identifies it as a proper name (Mrs., Dr., PhD). We created a tool based on this observation using substitution methods that was easy to implement and was largely based on publicly available data sources. We compiled a Clinical and Common Usage Word (CCUW) list as well as a fairly comprehensive proper name list. Despite the large overlap between these two lists, we were able to refine our methods to achieve accuracy similar to previous attempts at de-identification. Our method found 98.7% of 231 proper names in the narrative sections of pathology reports. Three single proper names were missed out of 1001 pathology reports (0.3%, no first name/last name pairs). It is unlikely that identification could be implied from this information. We will continue to refine our methods, specifically working to improve the quality of our CCUW and proper name lists to obtain higher levels of accuracy.

Effects of horizontal viewing angle on visual and audiovisual speech recognition

The authors investigated the effects of changes in horizontal viewing angle on visual and audiovisual speech recognition in 4 experiments, using a talker's face viewed full face, three quarters, and in profile. When only experimental items were shown (Experiments 1 and 2), identification of unimodal visual speech and visual speech influences on congruent and incongruent auditory speech were unaffected by viewing angle changes. However, when experimental items were intermingled with distractor items (Experiments 3 and 4), identification of unimodal visual speech decreased with profile views, whereas visual speech influences on congruent and incongruent auditory speech remained unaffected by viewing angle changes. These findings indicate that audiovisual speech recognition withstands substantial changes in horizontal viewing angle, but explicit identification of visual speech is less robust. Implications of this distinction for understanding the processes underlying visual and audiovisual speech recognition are discussed.

Cloning and characterization of a gene cluster for cyclododecanone oxidation in Rhodococcus ruber SC1

Biological oxidation of cyclic ketones normally results in formation of the corresponding dicarboxylic acids, which are further metabolized in the cell. Rhodococcus ruber strain SC1 was isolated from an industrial wastewater bioreactor that was able to utilize cyclododecanone as the sole carbon source. A reverse genetic approach was used to isolate a 10-kb gene cluster containing all genes required for oxidative conversion of cyclododecanone to 1,12-dodecanedioic acid (DDDA). The genes required for cyclododecanone oxidation were only marginally similar to the analogous genes for cyclohexanone oxidation. The biochemical function of the enzymes encoded on the 10-kb gene cluster, the flavin monooxygenase, the lactone hydrolase, the alcohol dehydrogenase, and the aldehyde dehydrogenase, was determined in Escherichia coli based on the ability to convert cyclododecanone. Recombinant E. coli strains grown in the presence of cyclododecanone accumulated lauryl lactone, 12-hydroxylauric acid, and/or DDDA depending on the genes cloned. The cyclododecanone monooxygenase is a type 1 Baeyer-Villiger flavin monooxygenase (FAD as cofactor) and exhibited substrate specificity towards long-chain cyclic ketones (C11 to C15), which is different from the specificity of cyclohexanone monooxygenase favoring short-chain cyclic compounds (C5 to C7).

N-WASP deficiency reveals distinct pathways for cell surface projections and microbial actin-based motility

The Wiskott-Aldrich syndrome protein (WASP) family of molecules integrates upstream signalling events with changes in the actin cytoskeleton. N-WASP has been implicated both in the formation of cell-surface projections (filopodia) required for cell movement and in the actin-based motility of intracellular pathogens. To examine N-WASP function we have used homologous recombination to inactivate the gene encoding murine N-WASP. Whereas N-WASP-deficient embryos survive beyond gastrulation and initiate organogenesis, they have marked developmental delay and die before embryonic day 12. N-WASP is not required for the actin-based movement of the intracellular pathogen Listeria but is absolutely required for the motility of Shigella and vaccinia virus. Despite these distinct defects in bacterial and viral motility, N-WASP-deficient fibroblasts spread by using lamellipodia and can protrude filopodia. These results imply a crucial and non-redundant role for N-WASP in murine embryogenesis and in the actin-based motility of certain pathogens but not in the general formation of actin-containing structures.

The cytoplasmic domain of the integrin alpha9 subunit requires the adaptor protein paxillin to inhibit cell spreading but promotes cell migration in a paxillin-independent manner

The integrin alpha9 subunit forms a single heterodimer, alpha9beta1. The alpha9 subunit is most closely related to the alpha4 subunit, and like alpha4 integrins, alpha9beta1 plays an important role in leukocyte migration. The alpha4 cytoplasmic domain preferentially enhances cell migration and inhibits cell spreading, effects that depend on interaction with the adaptor protein, paxillin. To determine whether the alpha9 cytoplasmic domain has similar effects, a series of chimeric and deleted alpha9 constructs were expressed in Chinese hamster ovary cells and tested for their effects on migration and spreading on an alpha9beta1-specific ligand. Like alpha4, the alpha9 cytoplasmic domain enhanced cell migration and inhibited cell spreading. Paxillin also specifically bound the alpha9 cytoplasmic domain and to a similar level as alpha4. In paxillin(-/-) cells, alpha9 failed to inhibit cell spreading as expected but surprisingly still enhanced cell migration. Further, mutations that abolished the alpha9-paxillin interaction prevented alpha9 from inhibiting cell spreading but had no effect on alpha9-dependent cell migration. These findings suggest that the mechanisms by which the cytoplasmic domains of integrin alpha subunits enhance migration and inhibit cell spreading are distinct and that the alpha9 and alpha4 cytoplasmic domains, despite sequence and functional similarities, enhance cell migration by different intracellular signaling pathways.

Recent origin of Plasmodium falciparum from a single progenitor

Genetic variability of Plasmodium falciparum underlies its transmission success and thwarts efforts to control disease caused by this parasite. Genetic variation in antigenic, drug resistance, and pathogenesis determinants is abundant, consistent with an ancient origin of P. falciparum, whereas DNA variation at silent (synonymous) sites in coding sequences appears virtually absent, consistent with a recent origin of the parasite. To resolve this paradox, we analyzed introns and demonstrated that these are deficient in single-nucleotide polymorphisms, as are synonymous sites in coding regions. These data establish the recent origin of P. falciparum and further provide an explanation for the abundant diversity observed in antigen and other selected genes.

Microbial nitrogen cycles: physiology, genomics and applications

Genes and pathways involved in inorganic nitrogen cycles have been found in traditional as well as unusual microorganisms. These pathways or enzymes play a very important role in the adaptation or survival of these microorganisms under a variety of environmental conditions. Microbial nitrogen metabolism has industrial applications ranging from wastewater treatment to bioremediation and potential future use in biocatalysis for chemical production.

The illusory-letters phenomenon: an illustration of graphemic restoration in visual word recognition

We present a demonstration of word perception in which stimuli containing very few letters (just 50% of their original number) are presented for unlimited durations and yet are seen unequivocally as complete words. The phenomenon suggests that recognition of words can be achieved even when perception of their component letters is prevented.

Techniques for the production of point-light and fully illuminated video displays from identical recordings

Illumination of only a few key points on a moving human body or face is enough to convey a compelling perception of human motion. A full understanding of the perception of biological motion from point-light displays requires accurate comparison with the perception of motion in normal, fully illuminated versions of the same images. Traditionally, these two types of stimuli (point-light and fully illuminated) have been filmed separately, allowing the introduction of uncontrolled variation across recordings. This is undesirable for accurate comparison of perceptual performance across the two types of display. This article describes simple techniques, using proprietary software, that allow production of point-light and fully illuminated video displays from identical recordings. These techniques are potentially useful for many studies of motion perception, by permitting precise comparison of perceptual performances across point-light displays and their fully illuminated counterparts with accuracy and comparative ease.

Short-term (30-day) outcome of endovascular treatment of abdominal aortic aneurism: results from the prospective Registry of Endovascular Treatment of Abdominal Aortic Aneurism (RETA)

OBJECTIVES

to assess the early morbidity and mortality of a new treatment, the endovascular repair of abdominal aortic aneurysms, during its introduction into clinical practice.

DESIGN

a prospective voluntary registry collecting demographic and risk factor data, details of aneurysm morphology, procedure performed, immediate and 30-day outcomes.

SETTING

thirty-one U.K. centres performing endovascular repair submitted data.

RESULTS

six hundred and eleven cases were registered in three years of data collection (January 1996 to December 1998). Four per cent of patients received an aortic tube device, 60% an aorto-bi-iliac device and 36% an aorto-uni-iliac device and a crossover graft (AUIC). Conversion to open repair was required in 5% of cases, with more conversions in the AUIC group (OR 2.9 (95% CI: 1.3-6.4)p=0.01). Post procedure complications occurred in 25% of cases. Unfit patients had significantly more complications than fit patients (35% vs 20% for fit patients (OR 1.8 (95% CI: 1.2-2.7)p=0.007)). At 30 days aneurysms were excluded in 90% of cases. Endoleaks were more common in larger aneurysms (2% if aneurysms were <6 cm in diameter vs 10% if >6 cm, OR 5.6 (95% CI: 2.1-14.9)p=0.0006). The overall mortality was 7% but was significantly higher for AUIC devices, (4% for combined aortic tube and bi-iliac devices (AT/BI) vs 12%, OR 2.6 (95% CI: 1.2-5.9 p=0.018)), and unfit patients (4% for fit patients vs 18%, OR 4.3 (95% CI: 2.0-9.5)p<0.001).

CONCLUSIONS

endovascular repair is feasible with short-term outcomes comparable to those of conventional surgical repair. In unfit patients the possible benefit in life expectancy gain must be balanced against the morbidity and mortality of the procedure.

A comparison of a printed patient summary document with its electronic equivalent: early results

Clinicians are always searching for efficient access to clinical data. The Regenstrief Medical Record System has a printed report that fills this niche: Pocket Rounds. Handheld computers may offer an alternative, but it is unclear how effectively a handheld computer can display such data. We surveyed residents and students on the general medicine services for their opinions regarding Pocket Rounds. Those with handheld computers were given access to an electronic version of Pocket Rounds-e-Rounds. We surveyed the subjects who used e-Rounds for their opinions on the electronic format and how it compared to paper. Users overall satisfaction with Pocket Rounds was 5.8 on a seven-point scale. User s overall satisfaction for e-Rounds was 5.6 on a seven-point scale. The most useful function was retrieval of lab data for both modalities. The results suggest that the electronic format is a viable alternative to paper. Further evaluation is needed, and we plan a prospective controlled trial to study this further.

Comparison of a range of green fluorescent protein-tagging vectors for monitoring a microbial inoculant in soil

Two new transposon-based tagging vectors have been constructed using the gfp marker gene under control of either constitutive or inducible promoters. The two vectors, along with the established pUTminiTn5gfp were used to tag a diesel-degrading Pseudomonas strain. Tagged strains were obtained that were not affected in terms of their growth or ability to use diesel as a carbon source. The transposon tags were stably maintained in the strains without selection and provided visible fluorescence as colonies or single cells in suspension. Tagging did not impede the survival of tagged Pseudomonas aeruginosa GP41B strains in diesel-contaminated soil microcosms. The tagged strains were easily recovered from the microcosms after a 3-month period. The tagging of bacteria with gfp using either native or introduced constitutive/inducible promoters is an effective and easy way to monitor their survival in soil.

Signalling by adhesion receptors

Over the past twenty years, intensive research has enabled us to identify components of specific signalling pathways downstream of an array of adhesion and growth-factor receptors. The first Gordon Research Conference on 'Signalling by Adhesion Receptors', which took place in Newport, Rhode Island, USA (23-28 July 2000), focused on these findings.

Minority recruitment in the prostate cancer prevention trial

PURPOSE

African American men have a higher prostate cancer risk profile than that of other men in the United States. The purpose of this manuscript is to summarize the challenges associated with enrolling and randomizing African American and other minority participants in the Prostate Cancer Prevention Trial (PCPT).

METHODS

The PCPT is a randomized trial of finasteride versus placebo for preventing prostate cancer in healthy men age 55 years and older; it is coordinated by the Southwest Oncology Group. The manuscript describes demographic and lifestyle characteristics of the PCPT randomized sample (18,882 men) by four racial and ethnic groups (Caucasian, African American, Hispanic, and other). African American men comprised 4% of the total randomized sample compared to our goal of 8%. Minority recruitment was emphasized through the Study Manual and training that occurred at trial activation. Supplemental minority recruitment activities were initiated a year after study activation and continued through the end of the accrual period. Minority recruitment was emphasized as follows: minority recruitment presentations at PCPT training seminars (held during twice yearly Southwest Oncology Group meetings); distribution of additional minority recruitment materials; engagement of four consultants for minority recruitment; production of a Minority Recruitment Manual; and a small pilot study involving minority outreach recruiters at five PCPT sites.

RESULTS

The consultants were helpful in implementing the pilot project and in suggesting and reviewing materials for minority recruitment. The five-site pilot project did not increase either enrollment or randomization of minorities (with a possible exception at one site).

CONCLUSIONS

We suggest that a long-term perspective is required for successful recruitment of minority participants in clinical trials. Likewise, extensive minority recruitment efforts must be ready to implement at trial activation.

Rhizosphere competitiveness of trichloroethylene-degrading, poplar-colonizing recombinant bacteria

Indigenous bacteria from poplar tree (Populus canadensis var. eugenei 'Imperial Carolina') and southern California shrub rhizospheres, as well as two tree-colonizing Rhizobium strains (ATCC 10320 and ATCC 35645), were engineered to express constitutively and stably toluene o-monooxygenase (TOM) from Burkholderia cepacia G4 by integrating the tom locus into the chromosome. The poplar and Rhizobium recombinant bacteria degraded trichloroethylene at a rate of 0.8 to 2.1 nmol/min/mg of protein and were competitive against the unengineered hosts in wheat and barley rhizospheres for 1 month (colonization occurred at a level of 1.0 x 10(5) to 23 x 10(5) CFU/cm of root). In addition, six of these recombinants colonized poplar roots stably and competitively with populations as large as 79% +/- 12% of all rhizosphere bacteria after 28 days (0.2 x 10(5) to 31 x 10(5) CFU/cm of root). Furthermore, five of the most competitive poplar recombinants (e.g., Pb3-1 and Pb5-1, which were identified as Pseudomonas sp. strain PsK recombinants) retained the ability to express TOM for 29 days as 100% +/- 0% of the recombinants detected in the poplar rhizosphere expressed TOM constitutively.

Visual and audiovisual speech perception with color and gray-scale facial images

Research has shown that auditory speech recognition is influenced by the appearance of a talker's face, but the actual nature of this visual information has yet to be established. Here, we report three experiments that investigated visual and audiovisual speech recognition using color, gray-scale, and point-light talking faces (which allowed comparison with the influence of isolated kinematic information). Auditory and visual forms of the syllables /ba/, /bi/, /ga/, /gi/, /va/, and /vi/ were used to produce auditory, visual, congruent, and incongruent audiovisual speech stimuli. Visual speech identification and visual influences on identifying the auditory components of congruent and incongruent audiovisual speech were identical for color and gray-scale faces and were much greater than for point-light faces. These results indicate that luminance, rather than color, underlies visual and audiovisual speech perception and that this information is more than the kinematic information provided by point-light faces. Implications for processing visual and audiovisual speech are discussed.

Genetic analysis of a gene cluster for cyclohexanol oxidation in Acinetobacter sp. Strain SE19 by in vitro transposition

Biological oxidation of cyclic alcohols normally results in formation of the corresponding dicarboxylic acids, which are further metabolized and enter the central carbon metabolism in the cell. We isolated an Acinetobacter sp. from an industrial wastewater bioreactor that utilized cyclohexanol as a sole carbon source. A cosmid library was constructed from Acinetobacter sp. strain SE19, and oxidation of cyclohexanol to adipic acid was demonstrated in recombinant Escherichia coli carrying a SE19 DNA segment. A region that was essential for cyclohexanol oxidation was localized to a 14-kb fragment on the cosmid DNA. Several putative open reading frames (ORFs) that were expected to encode enzymes catalyzing the conversion of cyclohexanol to adipic acid were identified. Whereas one ORF showed high homology to cyclohexanone monooxygenase from Acinetobacter sp. strain NCIB 9871, most of the ORFs showed only moderate homology to proteins in GenBank. In order to assign functions of the various ORFs, in vitro transposon mutagenesis was performed using the cosmid DNA as a target. A set of transposon mutants with a single insertion in each of the ORFs was screened for cyclohexanol oxidation in E. coli. Several of the transposon mutants accumulated a variety of cyclohexanol oxidation intermediates. The in vitro transposon mutagenesis technique was shown to be a powerful tool for rapidly assigning gene functions to all ORFs in the pathway.

Presentation of intravascular lymphomatosis as lumbosacral polyradiculopathy

A 53-year-old man developed progressive sensory disturbance and weakness in the legs, sphincter disturbance, back pain, systemic symptoms, and pancytopenia. Electrophysiological tests indicated a widespread lumbosacral polyradiculopathy. Spinal magnetic resonance imaging and routine cerebrospinal fluid analysis showed minor nonspecific abnormalities. Bone marrow and liver biopsies showed hemophagocytosis; and polymerase chain reaction of cerebrospinal fluid, bone marrow, and serum suggested active infection with human herpesvirus-6. Autopsy revealed that his neurological symptoms resulted from intravascular lymphomatosis (angiotropic large cell lymphoma), a rare variant of lymphoma with predilection for the nervous system.

Simultaneous identification of two cyclohexanone oxidation genes from an environmental Brevibacterium isolate using mRNA differential display

The technique of mRNA differential display was used to identify simultaneously two metabolic genes involved in the degradation of cyclohexanone in a new halotolerant Brevibacterium environmental isolate. In a strategy based only on the knowledge that cyclohexanone oxidation was inducible in this strain, the mRNA population of cells exposed to cyclohexanone was compared to that of control cells using reverse transcription-PCR reactions primed with a collection of 81 arbitrary oligonucleotides. Three DNA fragments encoding segments of flavin monooxygenases were isolated with this technique, leading to the identification of the genes of two distinct cyclohexanone monooxygenases, the enzymes responsible for the oxidation of cyclohexanone. Each monooxygenase was expressed in Escherichia coli and characterized. This work validates the application of mRNA differential display for the discovery of new microbial metabolic genes.

Plasma interleukin-6, tumour necrosis factor alpha and blood cytokine production in type 2 diabetes

Type 2 diabetes is associated with increased circulating concentrations of markers of the acute-phase response and interleukin-6 (IL-6). An augmented acute-phase response may be a mechanism which explains many of the clinical and biochemical features of type 2 diabetes and its complications. We sought to confirm that circulating concentrations of the cytokine acute-phase mediators IL-6 and tumour necrosis factor alpha [TNFalpha] are elevated in type 2 diabetes, and investigated blood as a source of cytokines in type 2 diabetes. Blood samples from 20 type 2 diabetic and 17 age-matched healthy subjects were incubated in vitro for 24 hr with and without lipopolysaccharide (LPS) stimulation and secreted cytokines measured. Plasma IL-6 and TNFalpha were significantly increased in type 2 diabetes compared to normal subjects. However, basal production of IL-6 and TNFalpha in cultured diabetic blood was markedly depressed in comparison with non-diabetic samples. IL-6 and TNFalpha production was increased in blood in response to LPS, reaching similar levels in diabetic and non-diabetic subjects, though IL-6 was slightly but significantly higher in controls. We conclude that circulating levels of IL-6 and TNFalpha are increased in type 2 diabetes but there is downregulation of basal cytokine production in blood cells in type 2 diabetes. Blood has the capacity to produce cytokines in diabetes which contribute to the augmented acute-phase response, but the main source of the increased plasma IL-6 and TNFalpha concentrations may be from non-circulating cells.

Completeness of excision and follow up cytology in patients treated with loop excision biopsy

AIMS

To assess the relation between the grade and the status of follow up cytology, the completeness of loop excision biopsies with cervical intraepithelial neoplasia (CIN), and the findings at follow up cytology, as well as the differences between complete and incomplete exclusion, using the odds ratio. Treatment failure was assessed.

METHODS

1600 women with CIN (290 CIN1, 304 CIN2, 1006 CIN3) were followed for a minimum of six months and a maximum of 10 years. A database was created and comparisons performed. The mean age of the patients was 37 years.

RESULTS

Excision was complete in over 84% of loops. Residual disease and recurrence of high grade dyskaryosis was more common in women with CIN 3 than CIN 2 or 1. No high grade dyskaryosis was seen in the fifth follow up smear in patients with CIN 1 and CIN 2. Residual, recurrent, and persistent disease was most common in patients with incompletely excised CIN at ectocervical and endocervical margins and deep margins of resection than in patients with completely excised CIN. The odds ratios were significantly higher in the women who had incomplete excision of CIN at ectocervical, endocervical, both ecto- and endocervical, and deep margins of resection compared with those with apparent complete excision of CIN lesions. One patient developed invasive squamous cell carcinoma 44 months after loop excision which showed CIN 3 invading endocervical crypts and extending to both ectocervical and endocervical margins of resection.

CONCLUSIONS

At long term follow up, patients with CIN who have residual disease are at increased risk of persistent disease and should therefore be followed up regularly with cytology and colposcopy. The findings support national policy of returning women with treated CIN of any grade to normal recall after five years except for cases of CIN3 where excision was incomplete or equivocal. In these cases follow up with annual smear for 10 years is recommended.

Binding of paxillin to alpha4 integrins modifies integrin-dependent biological responses

The alpha4 integrins are indispensable for embryogenesis, haematopoiesis and immune responses, possibly because alpha4 regulates cellular functions differently from other integrins through its cytoplasmic tail. We used novel mimics of the alpha4 tail to identify molecules that could account for alpha4-specific signalling. Here we report that the alpha4 tail, but not several other alpha-subunit tails, binds tightly to the signalling adaptor paxillin. Paxillin physically associated with alpha4 integrins in Jurkat T cells at high stoichiometry, and joining the alpha4 tail to alphaIIb resulted in a complex of integrin alphaIIbbeta3 with paxillin. This association markedly enhanced the rates of alphaIIbbeta3-dependent phosphorylation of focal adhesion kinase and cell migration. It also reduced cell spreading, focal adhesion and stress fibre formation. A point mutation within the alpha4 tail that disrupts paxillin binding reversed all of these effects. Furthermore, alpha4beta1-dependent adhesion to VCAM-1 led to spreading of mouse embryonic fibroblasts derived from paxillin-null but not from wild-type mice. Thus, the tight association of paxillin with the alpha4 tail leads to distinct biochemical and biological responses to integrin-mediated cell adhesion.

The application of a linear algebra to the analysis of mutation rates

Cells and bacteria growing in culture are subject to mutation, and as this mutation is the ultimate substrate for selection and evolution, the factors controlling the mutation rate are of some interest. The mutational event is not observed directly, but is inferred from the phenotype of the original mutant or of its descendants; the rate of mutation is inferred from the number of such mutant phenotypes. Such inference presumes a knowledge of the probability distribution for the size of a clone arising from a single mutation. We develop a mathematical formulation that assists in the design and analysis of experiments which investigate mutation rates and mutant clone size distribution, and we use it to analyse data for which the classical Luria-Delbrück clone-size distribution must be rejected.

Evaluation of transcriptional fusions with green fluorescent protein versus luciferase as reporters in bacterial mutagenicity tests

A bacterial plasmid was constructed on which the regulatory region of the umuC gene of Escherichia coli was fused to the coding sequence of the green fluorescent protein gene (gfp) from the jellyfish Aequorea victoria. Escherichia coli AB1157 strains carrying the plasmid emitted fluorescence in the presence of mutagens that induce the SOS DNA repair system. Data on tests with nitrosoguanidine, methylmethane sulphonate and UV radiation (254 nm) are presented. Although fluorescent detection using this system was not as rapid or sensitive as a similar luminescent equivalent (umuC-luxAB), the gfp reporter system was more robust. Escherichia coli umu gene induction was also analysed in Salmonella typhimurium TA1537 cells following plasmid transfer and exposure to the same range of mutagens. There was no significant difference in sensitivity between the two species. These preliminary results will provide the basis for development of mutagenicity test systems useful in the testing of complex mixtures, such as environmental samples, and the investigation of physiological parameters influencing spontaneous mutagenesis in bacteria.

Preponderance of hypokalaemia as a cause of acute onset quadriparesis in northern India/southern Nepal

Of 68 patients who were admitted with acute quadriparesis to a hospital in northern India, over 70% were found to be hypokalaemic. The most common cause of hypokalaemia was that associated with gastroenteritis (54%). These patients had all received intravenous fluids previously. It is likely that their hypokalaemia was caused by gastrointestinal loss compounded by parenteral fluid replacement. The next most common group of hypokalaemia-associated quadriparesis had no obvious cause for hypokalaemia (38%). Hypokalaemia-induced quadriparesis is a potentially life-threatening illness which can be readily treated with potassium supplements. The physician should consider hypokalaemia in patients who present with acute onset quadriparesis, and even if diagnostic tests for hypokalaemia are not available, should consider a judicious trial of potassium supplementation empirically, provided that there are no contraindications.

Vascular surgical society of great britain and ireland: RETA: the registry of endovascular treatment of abdominal aortic aneurysms

BACKGROUND: RETA is a voluntary registry within the UK established as a joint venture between radiologists and surgeons. The aim is to evaluate carefully the endovascular treatment of abdominal aortic aneurysms during introduction into clinical practice. METHODS: Some 367 patients have been included in the registry from 23 centres since its inception on 1 January 1996. In the majority (82 per cent) an elective repair was performed for an asymptomatic aneurysm. The mean age of the patients was 71.9 years and 28 per cent were deemed unsuitable for conventional repair. One hundred and ninety-nine bifurcated (54 per cent), 18 tube (5 per cent) and 148 aortouni-iliac with crossover (40 per cent) stent graft types were placed. RESULTS: At the end of the procedure 77 per cent of aneurysms were excluded with no complications. Twenty-one patients (6 per cent) required conversion to open repair. Forty-four (12 per cent) required additional endovascular procedures. At 30 days 87 per cent of the aneurysms were excluded or repaired. The 30-day mortality rate was 7 per cent (n = 24) with a significant improvement between 1996 and 1997, from 11 to 4 per cent. There were 25 persistent leaks (7 per cent). The death rate was related to the fitness of patient, device used and requirement for conversion. One-year follow-up data are available for 140 patients. There have been 13 deaths (9 per cent), three ruptures (2 per cent) and some form of complication in 20 per cent of cases overall. CONCLUSION: Improving results have been demonstrated for the primary procedure. At present there is a relatively high complication rate and ruptures have occurred. Rigorous continued follow-up is required.

Vascular surgical society of great britain and ireland: avoiding the complications of thrombolysis

BACKGROUND: NATALI is a voluntary database of patients undergoing peripheral vascular thrombolysis run on behalf of the Thrombolysis Study Group. The size of the data set allows analysis to identify predictors of outcome and complications. These may be patient factors or variables related to the technique used. METHODS: Since its inception on 1 January 1990, 798 thrombolytic events have been recorded. Details are collected on a wide range of factors: perceived risk factors; details of thrombolysis technique; complications; outcome; and adjunctive procedures. Using univariate and multivariate analysis, factors associated with an increased risk of complications were investigated. RESULTS: Death and complications (perilysis) occurred in 25.9 per cent of episodes (n = 207). Patient factors were the main influence on the risk of complications. Increasing age, use of aspirin and thrombolysis of grafts were significantly associated with an increased risk of complications after adjustment for confounders (P < 0.05). Female sex, the presence of peripheral vascular disease and Fontaine class were of borderline significance. Other patient factors were not associated with an increased risk of complication. Aspects of radiological technique, such as agent used, sheath size, length of lysis, dose of lysis, use of heparin or adjunctive procedures, had no relationship to the rate of complications. CONCLUSION: Case selection is the most important factor influencing the occurrence of complications. Radiological technique does not seem to influence the occurrence of complications.