Association between social deprivation status, age of presentation, and survival following ST-segment elevation myocardial infarction

Introduction

Many factors influence age of presentation with and survival following ST-segment myocardial infarction (STEMI). These include age, mode of, and time-delay to emergency treatment, diabetes and smoking. We sought to assess whether overall social deprivation status is associated with age of presentation and mortality following STEMI patients treated with primary PCI.

Methods

All patients treated emergently for STEMI in a large Northern Irish tertiary hospital from 2013 – 2017 were reviewed. Social deprivation is determined as a composite score relating to income, crime etc, and assigned to small geographical regions by the Northern Ireland Statistics and Research Agency. Deprivation score was assigned to patients based on their postcode. The database was ranked by social deprivation score and divided in to quintiles. The most (Grp 1) and least (Grp 5) deprived quintiles were compared. Mortality was determined from a national electronic health record.

Results

1,192 patients were included in the analysis. Mean follow up was 52.5 months (SD 15.6), minimum follow up was 35.6 months. There was no difference in gender: 70.1% male in Grp 1 vs 75.2% male in Grp 5 (p=0.68); no difference in ECG to balloon time: mean 89.9mins (95% CI 84.9–94.9) Grp 1 vs 90.5mins (95% CI 86.2–94.9) Grp 5 (p=0.86). The more deprived group was younger: mean age 60.6 (95% CI 59.5–61.6) vs 65.2 (95% CI 64.2–66.3) (p<0.000). Crude survival measured by Log-rank test was the same between the groups (p=0.52). Following Cox-regression adjustment for age, survival was longer in the least deprived group (p=0.042).

Conclusion

Social deprivation is associated with both a younger age of presentation with, and a higher mortality following STEMI. This is important variable is often overlooked in medical literature and should be further studied.

Funding Acknowledgement

Type of funding sources: None.

OP0258-HPR IS THERE A SUBSET OF PATIENTS WITH SJÖGREN’S SYNDROME WHO ARE MORE AT RISK FOR SEXUAL DYSFUNCTION? RESULTS FROM A SCOPING REVIEW

Background:

Individuals with Sjögren’s syndrome (SS) experience significantly higher levels of sexual dysfunction and sexual distress than healthy controls (van Nimwegen et al., 2015). Identifying associated factors may help to identify a subgroup of patients with SS who may benefit from early intervention to maintain sexual wellbeing and avoid unnecessary sexual disruption.

Objectives:

To explore and map the salient symptoms and factors that influence alterations in sexual functioning and intimate relationships for people with SS.

Methods:

The protocol for this review was registered with the Open Science Framework prior to commencement of the searches. The peer-reviewed search strings were used to search the following databases from inception to June 2019: Cochrane Library, CINAHL [EBSCO], MEDLINE [ProQuest], PUBMED [MEDLINE], ScienceDirect, Scopus and Web of Science. Grey literature was searched for on academic databases, topic-specific repositories, and Google Scholar. Databases were searched using key terms corresponding to sexual functioning and intimate relationships. Studies were included if their participant sample was comprised of adults aged ≥18 years, with a diagnosis of primary or secondary SS. Studies were not excluded based on source type, methodology or design. To qualify for inclusion, studies needed to have been peer-reviewed and available in English. Retrieved articles were then screened against the inclusion/exclusion criteria by two reviewers. Hand-searching was conducted on the reference lists of included articles, as well as the three most prevalent publishing journals until saturation had been achieved.

Results:

The search strategy returned 3527 unique citations. After screening processes were completed, only 19 articles met the inclusion criteria. Studies were predominately conducted in European countries (79%), within the last decade (68%; 2010-2019), and were mainly quantitative (n = 17; 89.5%), case-controlled (88.3%), and cross-sectional (100%) in nature. In total there were 1281 patients, 47% (n = 605) were patients with primary SS and the remaining 53% (n = 676) were patients with secondary SS. Both patient groups were predominately comprised of females (n = 600; 99% and n = 673; 99.5%, respectively), with a combined mean age of 50.82 years (M ranges = 35 – 62.82 years). An amalgamation of results from 17 studies, found that women with SS who score higher on the ESSPRI scale (total score and the subdomains of pain, fatigue and dryness) were more likely to experience significantly greater levels of vaginal dryness, sexual dysfunction and sexual distress. Moreover, women with SS who present with clinical levels of anxiety or depression were also more likely to experience disruptions in their sexual functioning and appraise their sexual life more negatively. Furthermore, patients who report greater severity of oral or ocular dryness, or dyspareunia may experience vaginal dryness, which may have ramifications on sexual functioning. Women of all ages are at risk of experiencing sexual dysfunctions, however, younger women (≤50 years) may experience more burdensome disruptions than older women. Finally, women who do not use lubrication products during sexual activity may be impacted further.

Figure 1.

Factors significantly associated with sexual dysfunction and sexual distress for patients with SS.

Conclusion:

Younger women (≤50) with SS who present with more severe symptoms of fatigue, pain, and oral or ocular dryness, or with clinical levels of anxiety or depression, may be at increased risk of experiencing sexual dysfunction and sexual distress. Healthcare professionals should be aware of these potential risk factors and initiate conversations around sexuality as and when a potentially ‘at risk’ individual is identified.

References:

[1]van Nimwegen, J. F., Arends, S., van Zuiden, G. S., Vissink, A., Kroese, F. G. M., & Bootsma, H. (2015). The impact of primary Sjögren’s syndrome on female sexual function. Rheumatology, 54(7), 1286-1293.

Disclosure of Interests:

None declared

P790 Bi-ventricular dysfunction in patients after bone marrow transplant: the value of strain imaging

Background

Cardiovascular events are a significant cause of morbidity and mortality in cancer survivors, particularly occurring at 5-10 years after their cancer therapy.

Purpose

To assess the utility of strain imaging by 2-dimensional (2D) speckle tracking echocardiography in detecting bi-ventricular dysfunction, as compared to traditional measures, in patients post bone marrow transplantation (BMT) with previous anthracycline (AC) therapy for haematological conditions.

Methods

50 consecutive patients post BMT + AC, reviewed at a long-term survivor clinic, were compared to 50 age and gender matched controls. 48/50 patients received AC doses below the recommended cumulative lifetime thresholds set by the European Society of Medical Oncology. 2D left ventricular global longitudinal strain (LV GLS) and right ventricle free wall strain (RV FWS) were compared to conventional measures of bi-ventricular function.

Results

The mean LVEF (58 ± 6% vs 63 ± 6%) and RV fractional area change (FAC) (39 ± 5% vs 44 ± 5%), although reduced in the BMT + AC group vs controls, were within normal limits. LV GLS was reduced in BMT + AC patients as compared to controls (-17.8 ± 3.1% vs -20.5 ± 2.2%, p < 0.01) while RV FWS was also reduced (-23.2 ± 4.0% vs -27.9 ± 2.7%, p < 0.001). In BMT + AC patients with a preserved LVEF (LVEF > 53%), 28% (11/40) had reduced GLS (GLS < -17%) while 52% (24/46) of those with preserved FAC (FAC > 35%) had reduced FWS (FWS < -25%). Major adverse cardiac events (MACE) occurred in 9/50 patients in the BMT + AC group and none in the control group. 8/9 patients had normal biventricular function as assessed by traditional parameters (LVEF and RV FAC) but 5/9 patients had reduced LV GLS and/or RV FWS.

Conclusions

Subclinical bi-ventricular dysfunction is common in patients post BMT + AC therapy, and can be detected using strain analysis, despite preserved LV and RV systolic function using conventional measures. MACE occurred at a significantly higher rate in BMT patients exposed to AC. More than half of MACE events occurred in patients with reduced LV or RV strain, with preserved bi-ventricular function by traditional measures. LV GLS and RV FWS should be utilised for early identification of subclinical dysfunction in BMT patients.

A randomised controlled trial and economic evaluation of intraoperative cell salvage during caesarean section in women at risk of haemorrhage: the SALVO (cell SALVage in Obstetrics) trial

BACKGROUND

Caesarean section is associated with blood loss and maternal morbidity. Excessive blood loss requires transfusion of donor (allogeneic) blood, which is a finite resource. Cell salvage returns blood lost during surgery to the mother. It may avoid the need for donor blood transfusion, but reliable evidence of its effects is lacking.

OBJECTIVES

To determine if routine use of cell salvage during caesarean section in mothers at risk of haemorrhage reduces the rates of blood transfusion and postpartum maternal morbidity, and is cost-effective, in comparison with standard practice without routine salvage use.

DESIGN

Individually randomised controlled, multicentre trial with cost-effectiveness analysis. Treatment was not blinded.

SETTING

A total of 26 UK obstetric units.

PARTICIPANTS

Out of 3054 women recruited between June 2013 and April 2016, we randomly assigned 3028 women at risk of haemorrhage to cell salvage or routine care. Randomisation was stratified using random permuted blocks of variable sizes. Of these, 1672 had emergency and 1356 had elective caesareans. We excluded women for whom cell salvage or donor blood transfusion was contraindicated.

INTERVENTIONS

Cell salvage (intervention) versus routine care without salvage (control). In the intervention group, salvage was set up in 95.6% of the women and, of these, 50.8% had salvaged blood returned. In the control group, 3.9% had salvage deployed.

MAIN OUTCOME MEASURES

Primary - donor blood transfusion. Secondary - units of donor blood transfused, time to mobilisation, length of hospitalisation, mean fall in haemoglobin, fetomaternal haemorrhage (FMH) measured by Kleihauer-Betke test, and maternal fatigue. Analyses were adjusted for stratification factors and other factors that were believed to be prognostic a priori. Cost-effectiveness outcomes - costs of resources and service provision taking the UK NHS perspective.

RESULTS

We analysed 1498 and 1492 participants in the intervention and control groups, respectively. Overall, the transfusion rate was 2.5% in the intervention group and 3.5% in the control group [adjusted odds ratio (OR) 0.65, 95% confidence interval (CI) 0.42 to 1.01; p = 0.056]. In a planned subgroup analysis, the transfusion rate was 3.0% in the intervention group and 4.6% in the control group among emergency caesareans (adjusted OR 0.58, 95% CI 0.34 to 0.99), whereas it was 1.8% in the intervention group and 2.2% in the control group among elective caesareans (adjusted OR 0.83, 95% CI 0.38 to 1.83) (interaction p = 0.46, suggesting that the difference in effect between subgroups was not statistically significant). Secondary outcomes did not differ between groups, except for FMH, which was higher under salvage in rhesus D (RhD)-negative women with RhD-positive babies (25.6% vs. 10.5%, adjusted OR 5.63, 95% CI 1.43 to 22.14; p = 0.013). No case of amniotic fluid embolism was observed. The additional cost of routine cell salvage during caesarean was estimated, on average, at £8110 per donor blood transfusion avoided.

CONCLUSIONS

The modest evidence for an effect of routine use of cell salvage during caesarean section on rates of donor blood transfusion was associated with increased FMH, which emphasises the need for adherence to guidance on anti-D prophylaxis. We are unable to comment on long-term antibody sensitisation effects. Based on the findings of this trial, cell salvage is unlikely to be considered cost-effective.

FUTURE WORK

Research into risk of alloimmunisation among women exposed to cell salvage is needed.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN66118656.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 2. See the NIHR Journals Library website for further project information.

Cost-effectiveness of cell salvage and donor blood transfusion during caesarean section: results from a randomised controlled trial

OBJECTIVES

To evaluate the cost-effectiveness of routine use of cell salvage during caesarean section in mothers at risk of haemorrhage compared with current standard of care.

DESIGN

Model-based cost-effectiveness evaluation alongside a multicentre randomised controlled trial. Three main analyses were carried out on the trial data: (1) based on the intention-to-treat principle; (2) based on the per-protocol principle; (3) only participants who underwent an emergency caesarean section.

SETTING

26 obstetric units in the UK.

PARTICIPANTS

3028 women at risk of haemorrhage recruited between June 2013 and April 2016.

INTERVENTIONS

Cell salvage (intervention) versus routine care without salvage (control).

PRIMARY OUTCOME MEASURES

Cost-effectiveness based on incremental cost per donor blood transfusion avoided.

RESULTS

In the intention-to-treat analysis, the mean difference in total costs between cell salvage and standard care was £83. The estimated incremental cost-effectiveness ratio (ICER) was £8110 per donor blood transfusion avoided. For the per-protocol analysis, the mean difference in total costs was £92 and the ICER was £8252. In the emergency caesarean section analysis, the mean difference in total costs was £55 and the ICER was £13 713 per donor blood transfusion avoided. This ICER is driven by the increased probability that these patients would require a higher level of postoperative care and additional surgeries. The results of these analyses were shown to be robust for the majority of deterministic sensitivity analyses.

CONCLUSIONS

The results of the economic evaluation suggest that while routine cell salvage is a marginally more effective strategy than standard care in avoiding a donor blood transfusion, there is uncertainty in relation to whether it is a less or more costly strategy. The lack of long-term data on the health and quality of life of patients in both arms of the trial means that further research is needed to fully understand the cost implications of both strategies.

TRIAL REGISTRATION NUMBER

ISRCTN66118656.

Development of a core outcome set for trials on induction of labour: an international multistakeholder Delphi study

OBJECTIVE

To develop a set of core outcomes to be minimally reported in trials on induction of labour.

DESIGN

Two-round Delphi survey and consensus meeting.

POPULATION

Four stakeholder groups: midwives, obstetricians, neonatologists, and women's representatives.

METHODS

Protocol registered with COMET (Registration Number: 695). Stakeholders rated reported outcomes for importance (1-limited to 9-critical). The median rating of each outcome was calculated. The consensus criteria to include outcomes were as follows: ≥70% participants rated outcomes as critical and <15% rated outcomes as limited importance. Outcomes that did not achieve consensus were taken to round two and, if there was still no consensus, to the final consensus meeting.

MAIN OUTCOME MEASURES

Outcomes in trials of induction of labour.

RESULTS

Of the 159 invited participants, 54% (86/159) completed the first round, and 83% completed the second round (71/86). The core outcome set included 28 core outcomes in four domains: Short-term maternal outcomes (n = 18)-cardiorespiratory arrest, damage to internal organs, death, haemorrhage, hysterectomy, infection, intensive care admission, length of hospital stay, mode of delivery, need for more than one induction agent, oxytocin augmentation, postnatal depression, pulmonary embolus, satisfaction with care, stroke, time from induction to delivery, uterine hyperstimulation, uterine scar dehiscence/rupture; short-term offspring outcomes (n = 8)-admission to the neonatal unit, birth trauma, death, hypoxic ischaemic encephalopathy/need for therapeutic hypothermia, meconium aspiration syndrome, need for respiratory support, infection, and seizures; long-term maternal outcomes (n = 1)-operative pelvic floor repair; long-term offspring outcomes (n = 1)-disability including neurodevelopmental delay.

CONCLUSION

Trials on induction of labour should include this core outcome set to standardise reporting.

TWEETABLE ABSTRACT

International multistakeholder Delphi study identifies a core outcome set for trials on induction of labour.

Oral health and dental morbidity in long-term allogeneic blood and marrow transplant survivors in Australia

BACKGROUND

Oral and dental disease is a major cause of long-term morbidity following allogeneic blood and marrow transplantation (Allo-BMT). This study aimed to describe the extent and range of oral and dental complications in BMT recipients and to identify gaps in service provision provided to this high-risk group.

METHODS

Participants were Allo-BMT recipients, aged >18 years, and received transplants between 2000 and 2012 in NSW. They completed seven surveys, the purpose-designed Sydney Post-BMT Study survey and six other validated instruments.

RESULTS

Of 441 respondents, many reported dry mouth (45.1%), dental caries (36.7%), mouth ulcers (35.3%), oral GVHD (35.1%), gingivitis (16.2%), tooth abscess (6.1%) and oral cancer (1.5%). Regular dental visits were reported by 66.2% of survivors. Middle-high income, older age and geographic location showed a positive association with regular dental visits. Of those who did not visit the dentist regularly, 37% stated they did not feel it necessary, 36% reported cost and 20% stated it was not advised by the treating team.

CONCLUSION

Despite oral complications commonly occurring after Allo-BMT, many survivors receive inadequate dental care. These results emphasize the need for improved oral health education, the importance of regular dental checks and improvement in the delivery of dental health services for BMT survivors.

Cell salvage and donor blood transfusion during cesarean section: A pragmatic, multicentre randomised controlled trial (SALVO)

BACKGROUND

Excessive haemorrhage at cesarean section requires donor (allogeneic) blood transfusion. Cell salvage may reduce this requirement.

METHODS AND FINDINGS

We conducted a pragmatic randomised controlled trial (at 26 obstetric units; participants recruited from 4 June 2013 to 17 April 2016) of routine cell salvage use (intervention) versus current standard of care without routine salvage use (control) in cesarean section among women at risk of haemorrhage. Randomisation was stratified, using random permuted blocks of variable sizes. In an intention-to-treat analysis, we used multivariable models, adjusting for stratification variables and prognostic factors identified a priori, to compare rates of donor blood transfusion (primary outcome) and fetomaternal haemorrhage ≥2 ml in RhD-negative women with RhD-positive babies (a secondary outcome) between groups. Among 3,028 women randomised (2,990 analysed), 95.6% of 1,498 assigned to intervention had cell salvage deployed (50.8% had salvaged blood returned; mean 259.9 ml) versus 3.9% of 1,492 assigned to control. Donor blood transfusion rate was 3.5% in the control group versus 2.5% in the intervention group (adjusted odds ratio [OR] 0.65, 95% confidence interval [CI] 0.42 to 1.01, p = 0.056; adjusted risk difference -1.03, 95% CI -2.13 to 0.06). In a planned subgroup analysis, the transfusion rate was 4.6% in women assigned to control versus 3.0% in the intervention group among emergency cesareans (adjusted OR 0.58, 95% CI 0.34 to 0.99), whereas it was 2.2% versus 1.8% among elective cesareans (adjusted OR 0.83, 95% CI 0.38 to 1.83) (interaction p = 0.46). No case of amniotic fluid embolism was observed. The rate of fetomaternal haemorrhage was higher with the intervention (10.5% in the control group versus 25.6% in the intervention group, adjusted OR 5.63, 95% CI 1.43 to 22.14, p = 0.013). We are unable to comment on long-term antibody sensitisation effects.

CONCLUSIONS

The overall reduction observed in donor blood transfusion associated with the routine use of cell salvage during cesarean section was not statistically significant.

TRIAL REGISTRATION

This trial was prospectively registered on ISRCTN as trial number 66118656 and can be viewed on http://www.isrctn.com/ISRCTN66118656.

The effect of a perioperative ketamine infusion on the incidence of chronic postsurgical pain-a pilot study

Chronic postsurgical pain (CPSP) is a common and debilitating complication of major surgery. We undertook a pilot study at three hospitals to assess the feasibility of a proposed large multicentre placebo-controlled randomised trial of intravenous perioperative ketamine to reduce the incidence of CPSP. Ketamine, 0.5 mg/kg pre-incision, 0.25 mg/kg/hour intraoperatively and 0.1 mg/kg/hour for 24 hours, or placebo, was administered to 80 patients, recruited over a 15-month period, undergoing abdominal or thoracic surgery under general anaesthesia. The primary endpoint was CPSP in the area of the surgery reported at six-month telephone follow-up using a structured questionnaire. Fourteen patients (17.5%) reported CPSP (relative risk [95% confidence interval] if received ketamine 1.18 [0.70 to 1.98], P=0.56). Four patients in the treatment group and three in the control group reported ongoing analgesic use to treat CPSP and two patients in each group reported their worst pain in the previous 24 hours at ≥3/10 at six months. There were no significant differences in adverse event rates, quality of recovery scores, or cumulative morphine equivalents consumption in the first 72 hours. Numeric Rating Scale pain scores (median [interquartile range, IQR]) for average pain in the previous 24 hours among those patients reporting CPSP were 17.5 [0 to 40] /100 with no difference between treatment groups. A large (n=4,000 to 5,000) adequately powered multicentre trial is feasible using this population and methodology.

Effects of feeding two RRR-α-tocopherol formulations on serum, cerebrospinal fluid and muscle α-tocopherol concentrations in horses with subclinical vitamin E deficiency

BACKGROUND

Alpha-tocopherol (α-TP) supplementation is recommended for the prevention of various equine neuromuscular disorders. Formulations available include RRR-α-TP acetate powder and a more expensive but rapidly water-dispersible liquid RRR-α-TP (WD RRR-α-TP). No cost-effective means of rapidly increasing serum and cerebrospinal fluid (CSF) α-TP with WD RRR-α-TP and then sustaining concentrations with RRR-α-TP acetate has yet been reported.

OBJECTIVES

To evaluate serum, CSF and muscle α-TP concentrations in an 8-week dosing regimen in which horses were transitioned from WD RRR-α-TP to RRR-α-TP acetate.

STUDY DESIGN

Non-randomised controlled trial.

METHODS

Healthy horses with serum α-TP of <2 μg/mL were divided into three groups and followed for 8 weeks. In the control group (n = 5), no α-TP was administered. In the second group (Group A; n = 7), 5000 IU/day RRR-α-TP acetate was administered. In the third group (Group WD-A; n = 7), doses of 5000 IU/day of WD RRR-α-TP were administered over 3 weeks, followed by a 4-week transition from WD RRR-α-TP to RRR-α-TP acetate, and a final 1 week of treatment with RRR-α-TP acetate. Serum samples were obtained weekly; muscle biopsies were obtained before, at 2.5 weeks and after supplementation. CSF samples were obtained before and after the 8-week period of supplementation.

RESULTS

Serum α-TP increased significantly in Group WD-A at week 1 and remained significantly higher than in Group A and the control group throughout the transition, with inter-individual variation in response. Serum α-TP increased significantly by week 7 in Group A. CSF α-TP increased significantly in Group WD-A only. Muscle α-TP concentrations did not differ significantly across groups. Serum and CSF α-TP were closely correlated (r = 0.675), whereas serum and muscle-α-TP concentrations were not correlated.

MAIN LIMITATIONS

The study duration was short and data on pre-transition CSF was lacking.

CONCLUSIONS

The administration of 5000 IU/day of water-dispersible RRR-α-TP rapidly increases serum α-TP. Serum and CSF α-TP concentrations are sustained with a gradual transition to 5000 IU/day of RRR-α-TP acetate. Periodic evaluation of serum α-TP concentrations is recommended because responses vary among individuals.

Structural basis for processive DNA synthesis by yeast DNA polymerase ε

DNA polymerase ε (Pol ε) is a high-fidelity polymerase that participates in leading-strand synthesis during eukaryotic DNA replication in eukaryotic cells. The 2.2 Å ternary structure of the 142 kDa catalytic core of Pol ε from Saccharomyces cerevisiae in complex with DNA and an incoming nucleotide has recently been determined [1]. The structure provides information about the selection of the correct nucleotide and the positions of amino acids that might be critical for proofreading activity. Pol ε has the highest fidelity among B-family polymerases despite the absence of an extended β-hairpin loop that is required for high-fidelity replication by other B-family polymerases. Moreover, the catalytic core has a new domain (i.e. the P-domain) that allows Pol ε to encircle the nascent double-stranded DNA and enhance processifivity of the polymerase. The structure provides valuable insights into the similarities and differences between Pol ε and other B-family polymerases, and suggests possible mechanisms responsible for the high processivity and fidelity of Pol ε.

A multicenter, randomized trial of flat dosing versus intrapatient dose escalation of single-agent carboplatin as first-line chemotherapy for advanced ovarian cancer: an SGCTG (SCOTROC 4) and ANZGOG study on behalf of GCIG

BACKGROUND

The aim of the study is to demonstrate that intrapatient dose escalation of carboplatin would improve the outcome in ovarian cancer compared with flat dosing.

PATIENTS AND METHODS

Patients with untreated stage IC-IV ovarian cancer received six cycles of carboplatin area under the curve 6 (AUC 6) 3 weekly either with no dose modification except for toxicity (Arm A) or with dose escalations in cycles 2-6 based on nadir neutrophil and platelet counts (Arm B). The primary end-point was progression-free survival (PFS).

RESULTS

Nine hundred and sixty-four patients were recruited from 71 centers. Dose escalation was achieved in 77% of patients who had ≥1 cycle. The median AUCs (cycle 2-6) received were 6.0 (Arm A) and 7.2 (Arm B) (P < 0.001). Grade 3/4 non-hematological toxicity was higher in Arm B (31% versus 22% P = 0.001). The median PFS was 12.1 months in Arm A and B [hazard ratio (HR) 0.99; 95% confidence interval (CI) 0.85-1.15; P = 0.93]. The median overall survival (OS) was 34.1 and 30.7 months in Arms A and B, respectively (HR 0.98; 95% CI 0.81-1.18, P = 0.82). In multivariate analysis, baseline neutrophil (P < 0.001), baseline platelet counts (P < 0.001) and the difference between white blood cell (WBC) and neutrophil count (P = 0.009) had a significant adverse prognostic value.

CONCLUSIONS

Intrapatient dose escalation of carboplatin based on nadir blood counts is feasible and safe. However, it provided no improvement in PFS or OS compared with flat dosing. Baseline neutrophils over-ride nadir counts in prognostic significance. These data may have wider implications particularly in respect of the management of chemotherapy-induced neutropenia.

Promiscuous DNA synthesis by human DNA polymerase θ

The biological role of human DNA polymerase θ (POLQ) is not yet clearly defined, but it has been proposed to participate in several cellular processes based on its translesion synthesis capabilities. POLQ is a low-fidelity polymerase capable of efficient bypass of blocking lesions such as abasic sites and thymine glycols as well as extension of mismatched primer termini. Here, we show that POLQ possesses a DNA polymerase activity that appears to be template independent and allows efficient extension of single-stranded DNA as well as duplex DNA with either protruding or multiply mismatched 3'-OH termini. We hypothesize that this DNA synthesis activity is related to the proposed role for POLQ in the repair or tolerance of double-strand breaks.

DNA polymerase ε

DNA polymerase ε (Pol ε) is one of three replicative DNA polymerases in eukaryotic cells. Pol ε is a multi-subunit DNA polymerase with many functions. For example, recent studies in yeast have suggested that Pol ε is essential during the initiation of DNA replication and also participates during leading strand synthesis. In this chapter, we will discuss the structure of Pol ε, the individual subunits and their function.

Lesion bypass activity of DNA polymerase θ (POLQ) is an intrinsic property of the pol domain and depends on unique sequence inserts

DNA polymerase θ (POLQ, polθ) is a large, multidomain DNA polymerase encoded in higher eukaryotic genomes. It is important for maintaining genetic stability in cells and helping protect cells from DNA damage caused by ionizing radiation. POLQ contains an N-terminal helicase-like domain, a large central domain of indeterminate function, and a C-terminal polymerase domain with sequence similarity to the A-family of DNA polymerases. The enzyme has several unique properties, including low fidelity and the ability to insert and extend past abasic sites and thymine glycol lesions. It is not known whether the abasic site bypass activity is an intrinsic property of the polymerase domain or whether helicase activity is also required. Three "insertion" sequence elements present in POLQ are not found in any other A-family DNA polymerase, and it has been proposed that they may lend some unique properties to POLQ. Here, we analyzed the activity of the DNA polymerase in the absence of each sequence insertion. We found that the pol domain is capable of highly efficient bypass of abasic sites in the absence of the helicase-like or central domains. Insertion 1 increases the processivity of the polymerase but has little, if any, bearing on the translesion synthesis properties of the enzyme. However, removal of insertions 2 and 3 reduces activity on undamaged DNA and completely abrogates the ability of the enzyme to bypass abasic sites or thymine glycol lesions.

Identification of a new motif in family B DNA polymerases by mutational analyses of the bacteriophage t4 DNA polymerase

Structure-based protein sequence alignments of family B DNA polymerases revealed a conserved motif that is formed from interacting residues between loops from the N-terminal and palm domains and between the N-terminal loop and a conserved proline residue. The importance of the motif for function of the bacteriophage T4 DNA polymerase was revealed by suppressor analysis. T4 DNA polymerases that form weak replicating complexes cannot replicate DNA when the dGTP pool is reduced. The conditional lethality provides the means to identify amino acid substitutions that restore replication activity under low-dGTP conditions either by correcting the defect produced by the first amino acid substitution or by generally increasing the stability of polymerase complexes; the second type are global suppressors that can effectively counter the reduced stability caused by a variety of amino acid substitutions. Some amino acid substitutions that increase the stability of polymerase complexes produce a new phenotype-sensitivity to the antiviral drug phosphonoacetic acid. Amino acid substitutions that confer decreased ability to replicate DNA under low-dGTP conditions or drug sensitivity were identified in the new motif, which suggests that the motif functions in regulating the stability of polymerase complexes. Additional suppressor analyses revealed an apparent network of interactions that link the new motif to the fingers domain and to two patches of conserved residues that bind DNA. The collection of mutant T4 DNA polymerases provides a foundation for future biochemical studies to determine how DNA polymerases remain stably associated with DNA while waiting for the next available dNTP, how DNA polymerases translocate, and the biochemical basis for sensitivity to antiviral drugs.

Primary and long-term stability of a short-stem hip implant

The new generation short-stem hip implants are designed to encourage physiological-like loading, to minimize stress—strain shielding and therefore implant loosening in the long term. As yet there are no long-term clinical studies available to prove the benefits of these short-stem implants. Owing to this lack of clinical data, numerical simulation may be used as a predictor of longer term behaviour. This finite element study predicted both the primary stability and long-term stability of a short-stem implant. The primary implant stability was evaluated in terms of interface micromotion. This study found primary stability to fall within the critical threshold for osseointegration to occur. Longer term stability was evaluated using a strain-adaptive bone remodelling algorithm to predict the long-term behaviour of the bone in terms of bone mineral density (BMD) changes. No BMD loss was observed in the classical Gruen zones 1 and 7 and bone remodelling patterns were comparable with hip resurfacing results in the literature.

Kinetics of mismatch formation opposite lesions by the replicative DNA polymerase from bacteriophage RB69

The fidelity of DNA replication is under constant threat from the formation of lesions within the genome. Oxidation of DNA bases leads to the formation of altered DNA bases such as 8-oxo-7,8-dihydroguanine, commonly called 8-oxoG, and 2-hydroxyadenine, or 2-OHA. In this work we have examined the incorporation kinetics opposite these two oxidatively derived lesions as well as an abasic site analogue by the replicative DNA polymerase from bacteriophage RB69. We compared the kinetic parameters for both wild type and the low fidelity L561A variant. While nucleotide incorporation rates (k(pol)) were generally higher for the variant, the presence of a lesion in the templating position reduced the ability of both the wild-type and variant DNA polymerases to form ternary enzyme-DNA-dNTP complexes. Thus, the L561A substitution does not significantly affect the ability of the RB69 DNA polymerase to recognize damaged DNA; instead, the mutation increases the probability that nucleotide incorporation will occur. We have also solved the crystal structure of the L561A variant forming an 8-oxoG.dATP mispair and show that the propensity for forming this mispair depends on an enlarged polymerase active site.

Prospective multicenter assessment of interobserver agreement for radiologist interpretation of multidetector computerized tomographic angiography for pulmonary embolism

BACKGROUND

Emergency physicians rely on the interpretation of radiologists to diagnose and exclude pulmonary embolism (PE) on the basis of computerized tomographic pulmonary angiography (CTPA). Few data exist regarding the interobserver reliability of this endpoint.

OBJECTIVE

To quantify the degree of agreement in CTPA interpretation between four academic hospitals and an independent reference reading (IRR) laboratory.

METHODS

Hospitalized and emergency department patients who had one predefined symptom and sign of PE and underwent 64-slice CTPA were enrolled from four academic hospitals. CTPA results as interpreted by board-certified radiologists from the hospitals were compared against those from the IRR laboratory. CTPAs were read as indeterminate, PE(-) or PE(+), and percentage obstruction was computed by the IRR laboratory, using a published method. Agreement was calculated with weighted Cohen's kappa.

RESULTS

We enrolled 492 subjects (63% female, age 54 +/- 1 years, and 16.7% PE(+) at the site hospitals). Overall agreement was 429/492 (87.2%; 95% confidence interval 83.9-90.0). We observed 13 cases (2.6%) of complete discordance, where one reading was PE(+) and the other reading was PE(-). Weighted agreement was 92.3%, with kappa = 0.75. The median percentage obstruction for all patients was 9% (25th-75th percentile interquartile range: 5% to -30%). For CTPAs interpreted at the site hospitals as PE(-) or indeterminate but read as PE(+) by the IRR laboratory, the median of percentage obstruction was 6% (4-7%).

CONCLUSION

We found in this sample a good level of agreement, with a weighted kappa of 0.75, but with 2.6% of patients having total discordance. Overall, a large proportion of clots were distal or minimally occlusive clots.

Genetic variation in RYR1 and malignant hyperthermia phenotypes

BACKGROUND

Malignant hyperthermia (MH) is associated, in the majority of cases, with mutations in RYR1, the gene encoding the skeletal muscle ryanodine receptor. Our primary aim was to assess whether different RYR1 variants are associated with quantitative differences in MH phenotype.

METHODS

The degree of in vitro pharmacological muscle contracture response and the baseline serum creatine kinase (CK) concentration were used to generate a series of quantitative phenotypes for MH. We then undertook the most extensive RYR1 genotype-phenotype correlation in MH to date using 504 individuals from 204 MH families and 23 RYR1 variants. We also determined the association between a clinical phenotype and both the laboratory phenotype and RYR1 genotype.

RESULTS

We report a novel correlation between the degree of in vitro pharmacological muscle contracture responses and the onset time of the clinical MH response in index cases (P<0.05). There was also a significant correlation between baseline CK concentration and clinical onset time (P=0.039). The specific RYR1 variant was a significant determinant of the severity of each laboratory phenotype (P<0.0001).

CONCLUSIONS

The MH phenotype differs significantly with different RYR1 variants. Variants leading to more severe MH phenotype are distributed throughout the gene and tend to lie at relatively conserved sites in the protein. Differences in phenotype severity between RYR1 variants may explain the variability in clinical penetrance of MH during anaesthesia and why some variants have been associated with exercise-induced rhabdomyolysis and heat stroke. They may also inform a mutation screening strategy in cases of idiopathic hyperCKaemia.

Use of 2-aminopurine fluorescence to study the role of the beta hairpin in the proofreading pathway catalyzed by the phage T4 and RB69 DNA polymerases

For DNA polymerases to proofread a misincorporated nucleotide, the terminal 3-4 nucleotides of the primer strand must be separated from the template strand before being bound in the exonuclease active center. Genetic and biochemical studies of the bacteriophage T4 DNA polymerase revealed that a prominent beta-hairpin structure in the exonuclease domain is needed to efficiently form the strand-separated exonuclease complexes. We present here further mutational analysis of the loop region of the T4 DNA polymerase beta-hairpin structure, which provides additional evidence that residues in the loop, namely, Y254 and G255, are important for DNA replication fidelity. The mechanism of strand separation was probed in in vitro reactions using the fluorescence of the base analogue 2-aminopurine (2AP) and mutant RB69 DNA polymerases that have modifications to the beta hairpin, to the exonuclease active site, or to both. We propose from these studies that the beta hairpin in the exonuclease domain of the T4 and RB69 DNA polymerases functions to facilitate strand separation, but residues in the exonuclease active center are required to capture the 3' end of the primer strand following strand separation.

A structural rationale for stalling of a replicative DNA polymerase at the most common oxidative thymine lesion, thymine glycol

Thymine glycol (Tg) is a common product of oxidation and ionizing radiation, including that used for cancer treatment. Although Tg is a poor mutagenic lesion, it has been shown to present a strong block to both repair and replicative DNA polymerases. The 2.65-A crystal structure of a binary complex of the replicative RB69 DNA polymerase with DNA shows that the templating Tg is intrahelical and forms a regular Watson-Crick base pair with the incorporated A. The C5 methyl group protrudes axially from the ring of the damaged pyrimidine and hinders stacking of the adjacent 5' template guanine. The position of the displaced 5' template guanine is such that the next incoming nucleotide cannot be incorporated into the growing primer strand, and it explains why primer extension past the lesion is prohibited even though DNA polymerases can readily incorporate an A across from the Tg lesion.

Structural and biochemical investigation of the role in proofreading of a beta hairpin loop found in the exonuclease domain of a replicative DNA polymerase of the B family

Replicative DNA polymerases, as exemplified by the B family polymerases from bacteriophages T4 and RB69, not only replicate DNA but also have the ability to proofread misincorporated nucleotides. Because the two activities reside in separate protein domains, polymerases must employ a mechanism that allows for efficient switching of the primer strand between the two active sites to achieve fast and accurate replication. Prior mutational and structural studies suggested that a beta hairpin structure located in the exonuclease domain of family B polymerases might play an important role in active site switching in the event of a nucleotide misincorporation. We show that deleting the beta hairpin loop in RB69 gp43 affects neither polymerase nor exonuclease activities. Single binding event studies with mismatched primer termini, however, show that the beta hairpin plays a role in maintaining the stability of the polymerase/DNA interactions during the binding of the primer DNA in the exonuclease active site but not on the return of the corrected primer to the polymerase active site. In addition, the deletion variant showed a more stable incorporation of a nucleotide opposite an abasic site. Moreover, in the 2.4 A crystal structure of the beta hairpin deletion variant incorporating an A opposite a templating furan, all four molecules in the crystal asymmetric unit have DNA in the polymerase active site, despite the presence of DNA distortions because of the misincorporation, confirming that the primer strand is not stably bound within the exonuclease active site in the absence of the beta hairpin loop.

Kinetics of error generation in homologous B-family DNA polymerases

The kinetics of forming a proper Watson-Crick base pair as well incorporating bases opposite furan, an abasic site analog, have been well characterized for the B Family replicative DNA polymerase from bacteriophage T4. Structural studies of these reactions, however, have only been performed with the homologous enzyme from bacteriophage RB69. In this work, the homologous enzymes from RB69 and T4 were compared in parallel reactions to determine the relative abilities of the two polymerases to incorporate correct nucleotides as well as to form improper pairings. The kinetic rates for three different exonuclease mutants for each enzyme were measured for incorporation of an A opposite T and an A opposite furan as well as for the formation of A:C and T:T mismatches. The T4 exonuclease mutants were all approximately 2- to 7-fold more efficient than the corresponding RB69 exonuclease mutants depending on whether a T or furan was in the templating position and which exonuclease mutant was used. The rates for mismatch formation by T4 were significantly reduced compared with incorporation opposite furan, much more so than the corresponding RB69 mutant. These results show that there are kinetic differences between the two enzymes but they are not large enough to preclude structural assumptions for T4 DNA polymerase based on the known structure of the RB69 DNA polymerase.

Bumps in the road: how replicative DNA polymerases see DNA damage

Significant advances have been made recently in the study of polymerases. First came the realization that there are many more DNA polymerases than originally thought; indeed, no fewer than 14 template-dependent DNA polymerases are found in mammals. Concurrent structural studies of DNA polymerases bound to DNA and incoming nucleotide have revealed how these remarkable copying machines select the correct deoxynucleoside triphosphate among a sea of nucleotides. A whole new level of insight into DNA replication fidelity has been reached as a result of recently determined crystal structures of DNA lesions in the context of the active sites of repair, replicative and specialized DNA polymerases. These structures illustrate why some lesions can be bypassed readily, whereas others are strong blocks to DNA replication.

Phase I dose-escalation trial of irinotecan with continuous infusion 5-FU first line, in metastatic colorectal cancer

This single-centre phase I trial was designed to determine the maximum tolerated dose of irinotecan and the recommended dose to use in combination with a fixed dose of 5-fluorouracil (5-FU) administered as a protracted venous infusion, for the first-line treatment of metastatic colorectal cancer (CRC). Tolerability and efficacy were secondary end points. In all, 22 patients, median age 57 years, were treated with escalating, weekly doses of irinotecan (50, 75, 100 and 85 mg m⁻²) in combination with 250 mg m⁻² 5-FU administered as a continuous infusion. All patients had measurable disease. The combination was well tolerated up to an irinotecan dose of 75 mg m⁻². However, three out of five patients at the 100 mg m⁻² irinotecan dose level had their dose reduced due to multiple grade 2 toxicities, and eventually one patient stopped treatment due to grade 3 diarrhoea and multiple grade 2 toxicities. Subsequent patients were recruited at an irinotecan dose level of 85 mg m⁻². The overall response rate was 55%, comprising one complete and 11 partial responses (PRs). Six patients also achieved sustained stable disease (SD), giving a clinical benefit (complete response/PR/SD) response of 82%. The median duration of response was 238 days (8.5 months) and median time to progression was 224 days (8.0 months). Two patients who achieved PRs underwent partial hepatectomies. Thus, irinotecan (85 mg m⁻²) combined with a continuous infusion of 5-FU (250 mg m⁻²) is an active and well-tolerated regimen for the treatment of metastatic CRC. It represents an effective treatment for patients who require close supervision and support, throughout their initial exposure to chemotherapy for this disease, and this dose combination was recommended for an ongoing phase II study.

Patient characteristics and quality of life among a sample of Australian chronic pain clinic attendees

BACKGROUND

Multidisciplinary chronic pain management programs have proliferated widely in recent decades. The clinical characteristics of patients attending these clinics are becoming the subject of increased research. Recent European data suggests that patients attending these clinics report very low quality of life.

AIMS

The present study profiles an Australian population in terms of demographics, clinical characteristics and quality of life, as measured by the Short Form 36 Quality of Life Questionnaire (SF-36).

METHODS

Data were collected prospectively from consecutive patients presenting to a multidisciplinary chronic pain clinic at a major Sydney metropolitan teaching-hospital. Cross-sectional analysis of demographic and clinical characteristics and quality of life were then undertaken.

RESULTS

Descriptive analysis of demographics and clinical characteristics suggest a patient population group reporting significant pain severity and reduced quality of life. The comparison of SF-36 domain scores between clinic patients and Australian norm values indicates a greatly reduced score on all SF-36 domains for clinic patients. Pain clinic patients reported the most profound effect upon quality of life in the role physical, physical function and social function domains of the SF-36. Stepwise multiple regression indicated impaired coping ability and depressive disability as the most significant correlates of low quality of life.

CONCLUSION

Patients who attend chronic pain clinics are likely to report low quality of life with an inability to cope. These findings suggest that future intervention research should explore the impacts of behavioural and self-management interventions. Psychological distress and ability to cope could be used as indices of improvement.

Crystallographic snapshots of a replicative DNA polymerase encountering an abasic site

Abasic sites are common DNA lesions, which are strong blocks to replicative polymerases and are potentially mutagenic when bypassed. We report here the 2.8 A structure of the bacteriophage RB69 replicative DNA polymerase attempting to process an abasic site analog. Four different complexes were captured in the crystal asymmetric unit: two have DNA in the polymerase active site whereas the other two molecules are in the exonuclease mode. When compared to complexes with undamaged DNA, the DNA surrounding the abasic site reveals distinct changes suggesting why the lesion is so poorly bypassed: the DNA in the polymerase active site has not translocated and is therefore stalled, precluding extension. All four molecules exhibit conformations that differ from the previously published structures. The polymerase incorporates dAMP across the lesion under crystallization conditions, indicating that the different conformations observed in the crystal may be part of the active site switching reaction pathway.

Likelihood ratio for trisomy 21 in fetuses with absent nasal bone at the 11-14-week scan

OBJECTIVE

To update the likelihood ratio for trisomy 21 in fetuses with absent nasal bone at the 11-14-week scan.

METHODS

Ultrasound examination of the fetal profile was carried out and the presence or absence of the nasal bone was noted immediately before karyotyping in 5918 fetuses at 11 to 13+6 weeks. Logistic regression analysis was used to examine the effect of maternal ethnic origin and fetal crown-rump length (CRL) and nuchal translucency (NT) on the incidence of absent nasal bone in the chromosomally normal and trisomy 21 fetuses.

RESULTS

The fetal profile was successfully examined in 5851 (98.9%) cases. In 5223/5851 cases the fetal karyotype was normal and in 628 cases it was abnormal. In the chromosomally normal group the incidence of absent nasal bone was related first to the ethnic origin of the mother, being 2.2% for Caucasians, 9.0% for Afro-Caribbeans and 5.0% for Asians; second to fetal CRL, being 4.7% for CRL of 45-54 mm, 3.4% for CRL of 55-64 mm, 1.4% for CRL of 65-74 mm and 1% for CRL of 75-84 mm; and third to NT, being 1.6% for NT < or = 95th centile, 2.7% for NT > 95th centile-3.4 mm, 5.4% for NT 3.5-4.4 mm, 6% for NT 4.5-5.4 mm and 15% for NT > or = 5.5 mm. In the chromosomally abnormal group there was absent nasal bone in 229/333 (68.8%) cases with trisomy 21 and in 95/295 (32.2%) cases with other chromosomal defects. Logistic regression analysis demonstrated that in the chromosomally normal fetuses significant independent prediction of the likelihood of absent nasal bone was provided by CRL, NT and Afro-Caribbean ethnic group, and in the trisomy 21 fetuses by CRL and NT. The likelihood ratio for trisomy 21 for absent nasal bone was derived by dividing the likelihood in trisomy 21 by that in normal fetuses.

CONCLUSION

At the 11-14-week scan the incidence of absent nasal bone is related to the presence or absence of chromosomal defects, CRL, NT and ethnic origin.

Angiogenic and immune parameters during recombinant interferon-alpha2b adjuvant treatment in patients with melanoma

As an adjuvant therapy for patients with high risk of recurrent melanoma, high-dose interferon (IFN)-alpha2b therapy has been shown to have some efficacy. We examined 22 patients with resected melanoma who were treated with repeated injections of recombinant IFN-alpha2b during the treatment. Both angiogenic and immune parameters were measured. White blood cells (WBCs) and lymphocyte numbers, lymphocyte subpopulations, serum concentrations of IFN-alpha and anti-IFN-alpha antibodies, and the serum vascular endothelial growth factor (VEGF), interleukin (IL)-8, and basis fibroblast growth factor (bFGF) concentrations were determined over time in resected, recurrence-free patients with American Joint Committee on Cancer (AJCC) stage III melanoma with one or less (LN+ < or = 1, n = 7) or more than one (LN+ > 1, n = 8) lymph nodes involved, and AJCC stage IV resected disease (n = 7). Follow-up and recurrence-free intervals were longer in stage III (LN+ < or = 1) patients compared with stage IV patients (P < 0.05). The number of WBCs and lymphocytes decreased during the treatment for all patient groups (P < 0.001). In addition, percentages of CD8 and CD20 were higher in stage IV patients than in stage III (LN+ > 1) and stage III (LN+ < or = 1) patients at the beginning of therapy (P < 0.05). A significant increase in the percentage of CD20+ cells, mostly B lymphocytes, was observed in the stage III (LN+ > 1) and stage III (LN+ < or = 1) patients over time but not in stage IV patients (P < 0.001). Low IL-8 and bFGF concentrations at the beginning of therapy were associated with significantly longer recurrence-free survival (P < 0.05). These results warrant a larger trial to determine if the differences observed in patients before treatment can provide prognostic markers in patients receiving IFN-alpha2b therapy.

Hyaluronan enters keratinocytes by a novel endocytic route for catabolism

Hyaluronan synthesized in the epidermis has an exceptionally short half-life, indicative of its catabolism by epidermal keratinocytes. An intracellular pool of endogenously synthesized hyaluronan, from 1 to 20 fg/cell, inversely related to cell density, was observed in cultured rat epidermal keratinocytes. More than 80% of the intracellular hyaluronan was small (<90 kDa). Approximately 25% of newly synthesized hyaluronan was endocytosed by the keratinocytes and had a half-life of 2-3 h. A biotinylated aggrecan G(1) domain/link protein probe demonstrated hyaluronan in small vesicles of approximately 100 nm diameter close to the plasma membrane, and in large vesicles and multivesicular bodies up to 1300 nm diameter around the nucleus. Hyaluronan did not co-localize with markers of lysosomes. However, inhibition of lysosomal acidification with NH(4)Cl or chloroquine, or treating the cells with the hyaluronidase inhibitor apigenin increased intracellular hyaluronan staining, suggesting that it resided in prelysosomal endosomes. Competitive displacement of hyaluronan from surface receptors using hyaluronan decasaccharides, resulted in a rapid disappearance of this endosomal hyaluronan (t(12) approximately 5 min), indicating its transitory nature. The ultrastructure of the hyaluronan-containing vesicles, co-localization with marker proteins for different vesicle types, and application of specific uptake inhibitors demonstrated that the formation of hyaluronan-containing vesicles did not involve clathrin-coated pits or caveolae. Treatment of rat epidermal keratinocytes with the OX50 monoclonal antibody against the hyaluronan receptor CD44 increased endosomal hyaluronan. However, no CD44-hyaluronan co-localization was observed intracellularly unless endosomal trafficking was retarded by monensin, or cultivation at 20 degrees C, suggesting CD44 recycling. Rat epidermal keratinocytes thus internalize a large proportion of their newly synthesized hyaluronan into non-clathrin-coated endosomes in a receptor mediated way, and rapidly transport it to slower degradation in the endosomal/lysosomal system.

A preformed basal lamina alters the metabolism and distribution of hyaluronan in epidermal keratinocyte "organotypic" cultures grown on collagen matrices

A rat epidermal keratinocyte (REK) line which exhibits histodifferentiation nearly identical to the native epidermis when cultured at an air-liquid interface was used to study the metabolism of hyaluronan, the major intercellular macromolecule present in basal and spinous cell layers. Two different support matrices were used: reconstituted collagen fibrils with and without a covering basal lamina previously deposited by canine kidney cells. REKs formed a stratified squamous, keratinized epithelium on both support matrices. Hyaluronan and its receptor, CD44, colocalized in the basal and spinous layers similar to their distribution in the native epidermis. Most (approximately 75%) of the hyaluronan was retained in the epithelium when a basal lamina was present while most (approximately 80%) diffused out of the epithelium in its absence. While REKs on the two matrices synthesized hyaluronan at essentially the same rate, catabolism of this macromolecule was much higher in the epithelium on the basal lamina (half-life approximately 1 day, similar to its half-life in native human epidermis). The formation of a true epidermal compartment in culture bounded by the cornified layer on the surface and the basal lamina subjacent to the basal cells provides a good model within which to study epidermal metabolism.

The case-based Internet textbook ODITEB for multi-modal diagnosis of tumors--development, features and first experiences

Internet technologies offer the chance to build high-quality learning media for the education in medicine. In particular, the teaching of diagnostics with medical imaging can be supported by the excellent visualization and interaction capabilities. In cooperation with three radiological departments at German universities in Munich, Erlangen and Würzburg the distributed case-based Internet textbook ODITEB for tumor diagnosis of the GI-tract, liver, pancreas and thorax has been developed. It offers a growing collection of didactically prepared cases located on servers at the provider sites Munich, Erlangen and Würzburg, functionality similar to a real CT console, original DICOM data, X-rays and endoscopic and endosonographic videos, and expert-guided tours through the cases. In a first evaluation in summer 1998, 32 medical students graded the application with 1.9 ('good') on a scale from 1 ('very good') to 5 ('very bad').

Concepts of a Web-based open distributed textbook for the multimodal diagnostics of gastrointestinal tumours with MRI, CT and video-endoscopy addressing students of medicine and students of medical informatics as two different target groups

Multimodal diagnostics of gastrointestinal tumours with MRI, CT and video-endoscopy is a rapidly changing domain. The education at our universities should overcome the obstacles of traditional learning based on paper media and oral lectures with retention rates of 10-30% only. The paper presents the objectives and the results of the design phase of the project ODITEB1-Open Distributed TExt Book, for Computer-Assisted Instruction in the domain mentioned above. The main objective is to produce an electronic interactive textbook in order to shift education to more efficient learning settings with higher retention rates. The main concepts are 1) three-layer architecture (dynamic case layer, intermediate query layer, static instruction layer) 2) case pool distribution 3) active learners experience (interactive exploration of original image data).