1023 The Role of Social Media in Disseminating Plastic Surgery Research: The Relationship Between Citations, Altmetrics and Article Characteristics

Background

Social media (SoMe) enable the dissemination of content immediately and directly to interested end-users. Alternative metrics (altmetrics) are non-traditional bibliometrics which describe the exposure and impact of an article on freely available platforms such as Twitter and Facebook. Altmetrics within days of publication are associated with ultimate citation counts in various medical disciplines, except plastic surgery which represents the rationale for this study.

Method

Altmetric explorer was used to extract altmetrics and citation rates for articles published during 2018 in Plastic and Reconstructive Surgery (PRS), the Journal of Plastic, Reconstructive and Aesthetic Surgery, the Annals of Plastics Surgery and Plastic Surgery. Multivariable negative binomial regression was used to estimate the relationship between citations and predictors (presented as the incidence rate ratio, IRR with 95% confidence interval, CI).

Results

Overall, 1215 articles were captured. On average, articles published in PRS were cited nearly five times as often as articles published elsewhere (adjusted IRR 4.77 [95% CI 2.36, 9.62]). Overall, SoMe mentions were positively associated with citation rates (adjusted IRR 1.01 [95% CI 1.01, 1.1]); marginal analysis showed that 45 mentions translated to one extra citation.

Conclusions

Dissemination of plastic surgery research through SoMe channels are associated with significant improvements in short term citations rates.

P3824Body composition and mortality from vascular or metabolic causes among 150,000 participants in the Mexico City Prospective Study

Background

Higher body-mass index is associated with increased mortality from vascular disease, renal disease and other metabolic causes. However, body mass reflects both fat and lean mass, which may have very different effects on risk. We investigated the individual and joint relevance of fat and lean mass to mortality from these causes, using data from the Mexico City Prospective Study.

Methods

Between 1998 and 2004, 150,000 adults from Mexico City were recruited into a prospective study and tracked for cause-specific mortality for 14 years. Fat and lean mass at recruitment were predicted using Mexican-specific anthropometric equations, validated in a subset of participants with additional bio-impedance measures. Cox regression was used to assess the relevance of fat and lean mass at recruitment to mortality from a vascular, renal, or other metabolic cause at ages 35–74 years. Analyses were adjusted for age at risk, sex, residential district, education, recreational physical activity, smoking and alcohol consumption. To avoid reverse causality, analyses excluded those with diabetes or other chronic diseases at recruitment, and deaths in the first 5 years of follow-up. Mortality rate ratios (RRs) relate to the differences per SD of the usual values of various factors or the differences between the top tenth and bottom fifth of the values.

Results

Among 112,923 participants aged 35–74 years, mean (SD) fat mass in men and women was 22.0 (6.4) kgs and 29.4 (7.8) kgs respectively, while mean (SD) lean mass was 54.9 (7.2) kgs and 39.2 (5.0) kgs respectively. In both men and women, equation-predicted fat and lean mass closely matched the bio-impedance values (all r>0.86). Both fat and lean mass were positively and approximately log-linearly associated with mortality from a vascular or metabolic cause. However, the association of lean mass with mortality was more than accounted for by the correlation of lean with fat mass. Hence, after adjustment for fat mass, lean mass was inversely associated with risk. For a given amount of fat mass, the RR for vascular/metabolic mortality comparing those in the top tenth versus bottom fifth of the predicted lean mass was 0.35 (95% CI 0.24–0.52). Conversely, for a given amount of lean mass, the RR comparing those in the top tenth versus bottom fifth of the predicted fat mass was 4.06 (3.06–5.39). The RRs associated with each SD higher fat mass (1.51, 1.40–1.63) or lean mass (0.79, 0.73–0.86) appeared to be little affected by age, sex, or levels of other confounders, and were broadly similar for the major vascular, renal, and other metabolic mortality. The height-adjusted RRs were 1.41 (1.30–1.53) for fat mass and 0.91 (0.82–1.00) for lean mass.

Conclusions

In this Mexican cohort, predicted fat and lean mass had opposing effects on vascular and other metabolic deaths, with no evidence of any thresholds throughout the ranges studied.

Improving Outcomes Through Principles of Best Practice Management: Australia's National Lung Cancer Framework

Background and context: Lung cancer is estimated to be the fifth most commonly diagnosed cancer and leading cause of cancer death in Australia, representing 9.2% of all new cancer cases (n = 138,321) diagnosed and 18.9% of all cancer deaths (n = 48,586). The 5-year survival rate for those with lung cancer is 16%, compared with 68% for all cancers combined (between 2009 and 2013). Lung cancer is also the leading cause of cancer burden in Australia and patients affected by lung cancer may experience high levels of unmet need with associated psychological distress and decreased quality of life. Cancer Australia, Australia's national cancer control agency, developed the national Lung Cancer Framework: Principles for Best Practice Lung Cancer Care (Framework) to provide evidence-based, best practice information, strategies, tools and resources to support local adoption of the 5 principles for best practice management of lung cancer (principles): patient-centered care; multidisciplinary care; timely access to evidence-based care; coordination, communication and continuity of care; and data-driven improvements. Aim: The framework aims to improve the outcomes and experiences of people affected by lung cancer in Australia by supporting national uptake of the principles. Strategy/Tactics: Cancer Australia: • established a Lung Cancer Advisory Group to advise on strategies for national implementation of the framework and its principles • conducted a national lung cancer demonstration project, with advice from an Expert Steering Group, to demonstrate the delivery of lung cancer care according to the principles across a range of service delivery settings, and identify key factors contributing to ongoing delivery of best practice cancer care • completed systematic reviews for each principle to determine the effectiveness of the principles in improving lung cancer care processes and outcomes. Program/Policy process: To support national adoption of the framework and its principles, Cancer Australia: • developed a promotion and communication strategy for widespread national dissemination • convened a National Summit to bring together policy makers, clinical stakeholders and consumers to support local application of the principles, and drive optimal care for people affected by lung cancer • identified and communicated consumer, service, and system-level approaches to aid sustainable use of the principles. Outcomes: The evidence-based approach to the development of the framework and its principles identified ways to improve the healthcare system to achieve better outcomes for those affected by lung cancer in Australia. A coordinated approach to the delivery of the National Summit supported those involved in lung cancer care to share and adopt innovative and multilevel strategies for best practice care. What was learned: Embedding strategies to support implementation of the principles, responsive to local context, was key to enabling sustainable improvements in national lung cancer control.

Interventional management of hyperhidrosis in secondary care: a systematic review

BACKGROUND

Hyperhidrosis is uncontrollable excessive sweating, which occurs at rest, regardless of temperature. The symptoms of hyperhidrosis can significantly affect quality of life.

OBJECTIVES

To undertake a systematic review of the clinical effectiveness and safety of treatments available in secondary care for the management of primary hyperhidrosis.

METHODS

Fifteen databases (including trial registers) were searched to July 2016 to identify studies of secondary-care treatments for primary hyperhidrosis. For each intervention randomized controlled trials (RCTs) were included where available; where RCT evidence was lacking, nonrandomized trials or large prospective case series were included. Outcomes of interest included disease severity, sweat rate, quality of life, patient satisfaction and adverse events. Trial quality was assessed using a modified version of the Cochrane Risk of Bias tool. Results were pooled in pairwise meta-analyses where appropriate, otherwise a narrative synthesis was presented.

RESULTS

Fifty studies were included in the review: 32 RCTs, 17 nonrandomized trials and one case series. The studies varied in terms of population, intervention and methods of outcome assessment. Most studies were small, at high risk of bias and poorly reported. The interventions assessed were iontophoresis, botulinum toxin (BTX) injections, anticholinergic medications, curettage and newer energy-based technologies that damage the sweat gland.

CONCLUSIONS

The evidence for the effectiveness and safety of treatments for primary hyperhidrosis is limited overall, and few firm conclusions can be drawn. However, there is moderate-quality evidence to support the use of BTX for axillary hyperhidrosis. A trial comparing BTX with iontophoresis for palmar hyperhidrosis is warranted.

Constant Isothiocyanate-Release Potentials across Biofumigant Seeding Rates

Biofumigation is an integrated pest-management method involving the mulching of a glucosinolate-containing cover crop into a field in order to generate toxic isothiocyanates (ITCs), which are effective soil-borne-pest-control compounds. Variation in biofumigation efficacy demonstrates a need to better understand the factors affecting pest-control outcomes and develop best practices for choosing biofumigants, growth conditions, and mulching methods that allow the greatest potential isothiocyanate release. We measured the glucosinolate concentrations of six different commercial varieties of three biofumigant plant species: Brassica juncea (ISCI99, Vitasso, and Scala) Raphanus sativus (Diablo and Bento), and Sinapis alba (Ida Gold). The plants were grown in the range of commercially appropriate seeding rates and sampled at three growth stages (early development, mature, and 50% flowering). Within biofumigant species, the highest ITC-release potentials were achieved with B. juncea cv. ISCI99 and R. sativus cv. Bento. The highest ITC-release potential occurred at the 50% flowering growth stage across the species. The seeding rate had a minor impact on the ITC-release potential of R. sativus but had no significant effects on the ITC-release potentials of the B. juncea or S. alba cultivars.

Skin involvement in Dupuytren's disease

Whether the palmar skin has a role in the development, propagation or recurrence of Dupuytren's disease remains unclear. Clinical assessment for skin involvement is difficult and its correlation with histology uncertain. We prospectively biopsied the palmar skin of consecutive patients undergoing single digit fasciectomy (for primary Dupuytren's disease without clinically involved skin) and dermofasciectomy (for clinically involved skin or recurrence) in order to investigate this relationship. We found dermal fibromatosis in 22 of 44 patients (50%) undergoing fasciectomy and 41 of 59 patients (70%) undergoing dermofasciectomy. Dermal fibromatosis appeared to be associated with greater preoperative angular deformity, presence of palmar nodules and occupations involving manual labour. Dermal fibromatosis exists in the absence of clinical features of skin involvement and we hypothesize that the skin may have a greater role in the development and propagation of Dupuytren's disease than previously thought.

LEVEL OF EVIDENCE

III.

Adjunctive colposcopy technologies for examination of the uterine cervix--DySIS, LuViva Advanced Cervical Scan and Niris Imaging System: a systematic review and economic evaluation

BACKGROUND

Women in England (aged 25-64 years) are invited for cervical screening every 3-5 years to assess for cervical intraepithelial neoplasia (CIN) or cancer. CIN is a term describing abnormal changes in the cells of the cervix, ranging from CIN1 to CIN3, which is precancerous. Colposcopy is used to visualise the cervix. Three adjunctive colposcopy technologies for examination of the cervix have been included in this assessment: Dynamic Spectral Imaging System (DySIS), the LuViva Advanced Cervical Scan and the Niris Imaging System.

OBJECTIVE

To determine the clinical effectiveness and cost-effectiveness of adjunctive colposcopy technologies for examination of the uterine cervix for patients referred for colposcopy through the NHS Cervical Screening Programme.

DATA SOURCES

Sixteen electronic databases [Allied and Complementary Medicine Database (AMED), BIOSIS Previews, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Database of Abstracts of Reviews of Effects (DARE), EMBASE, Health Management Information Consortium (HMIC), Health Technology Assessment (HTA) database; Inspec, Inside Conferences, MEDLINE, NHS Economic Evaluation Database (NHS EED), PASCAL, Science Citation Index Expanded (SCIE) and Science Citation Index (SCI) - Conference Proceedings], and two clinical trial registries [ClinicalTrials.gov and Current Controlled Trials (CCT)] were searched to September-October 2011.

REVIEW METHODS

Studies comparing DySIS, LuViva or Niris with conventional colposcopy were sought; a narrative synthesis was undertaken. A decision-analytic model was developed, which measured outcomes in terms of quality-adjusted life-years (QALYs) and costs were evaluated from the perspective of the NHS and Personal Social Services with a time horizon of 50 years.

RESULTS

Six studies were included: two studies of DySIS, one study of LuViva and three studies of Niris. The DySIS studies were well reported and had a low risk of bias; they found higher sensitivity with DySIS (both the DySISmap alone and in combination with colposcopy) than colposcopy alone for identifying CIN2+ disease, although specificity was lower with DySIS. The studies of LuViva and Niris were poorly reported and had limitations, which indicated that their results were subject to a high risk of bias; the results of these studies cannot be considered reliable. The base-case cost-effectiveness analysis suggests that both DySIS treatment options are less costly and more effective than colposcopy alone in the overall weighted population; these results were robust to the ranges tested in the sensitivity analysis. DySISmap alone was more costly and more effective in several of the referral groups but the incremental cost-effectiveness ratio (ICER) was never higher than £1687 per QALY. DySIS plus colposcopy was less costly and more effective in all reasons for referral. Only indicative analyses were carried out on Niris and LuViva and no conclusions could be made on their cost-effectiveness.

LIMITATIONS

The assessment is limited by the available evidence on the new technologies, natural history of the disease area and current treatment patterns.

CONCLUSIONS

DySIS, particularly in combination with colposcopy, has higher sensitivity than colposcopy alone. There is no reliable evidence on the clinical effectiveness of LuViva and Niris. DySIS plus colposcopy appears to be less costly and more effective than both the DySISmap alone and colposcopy alone; these results were robust to the sensitivity analyses undertaken. Given the lack of reliable evidence on LuViva and Niris, no conclusions on their potential cost-effectiveness can be drawn. There is some uncertainty about how generalisable these findings will be to the population of women referred for colposcopy in the future, owing to the introduction of the human papillomavirus (HPV) triage test and uptake of the HPV vaccine.

Impact of NOTCH1/FBXW7 mutations on outcome in pediatric T-cell acute lymphoblastic leukemia patients treated on the MRC UKALL 2003 trial

Activating mutations in the NOTCH1 pathway are frequent in pediatric T-cell acute lymphoblastic leukemia (T-ALL) but their role in refining risk stratification is unclear. We screened 162 pediatric T-ALL patients treated on the MRC UKALL2003 trial for NOTCH1/FBXW7 gene mutations and related genotype to response to therapy and long-term outcome. Overall, 35% were wild-type (WT) for both genes (NOTCH1(WT)FBXW7(WT)), 38% single NOTCH1 mutant (NOTCH1(Single)FBXW7(WT)), 3% just FBXW7 mutant (NOTCH1(WT)FBXW7(MUT)) and 24% either double NOTCH1 mutant (NOTCH1(Double)FBXW7(WT)) or mutant in both genes (NOTCH1(MUT)FBXW7(MUT)), hereafter called as NOTCH1±FBXW7(Double). There was no difference between groups in early response to therapy, but NOTCH1±FBXW7(Double) patients were more likely to be associated with negative minimal residual disease (MRD) post-induction than NOTCH1(WT)FBXW7(WT) patients (71% versus 40%, P=0.004). Outcome improved according to the number of mutations, overall survival at 5 years 82%, 88% and 100% for NOTCH1(WT)FBXW7(WT), NOTCH1(Single)FBXW7(WT) and NOTCH1±FBXW7(Double) patients, respectively (log-rank P for trend=0.005). Although 14 NOTCH1±FBXW7(Double) patients were classified as high risk (slow response and/or MRD positive), only two had disease progression and all remain alive. Patients with double NOTCH1 and/or FBXW7 mutations have a very good outcome and should not be considered for more intensive therapy in first remission, even if slow early responders or MRD positive after induction therapy.

EOS 2D/3D X-ray imaging system: a systematic review and economic evaluation

BACKGROUND

EOS is a biplane X-ray imaging system manufactured by EOS Imaging (formerly Biospace Med, Paris, France). It uses slot-scanning technology to produce a high-quality image with less irradiation than standard imaging techniques.

OBJECTIVE

To determine the clinical effectiveness and cost-effectiveness of EOS two-dimensional (2D)/three-dimensional (3D) X-ray imaging system for the evaluation and monitoring of scoliosis and other relevant orthopaedic conditions.

DATA SOURCES

For the systematic review of EOS, electronic databases (MEDLINE, Allied and Complementary Medicine Database, BIOSIS Previews, Cumulative Index to Nursing and Allied Health Literature, The Cochrane Library, EMBASE, Health Management Information Consortium, Inspec, ISI Science Citation Index and PASCAL), clinical trials registries and the manufacturer's website were searched from 1993 to November 2010.

REVIEW METHODS

A systematic review of studies comparing EOS with standard X-ray [film, computed radiography (CR) or digital radiography] in any orthopaedic condition was performed. A narrative synthesis was undertaken. A decision-analytic model was developed to assess the cost-effectiveness of EOS in the relevant indications compared with standard X-ray and incorporated the clinical effectiveness of EOS and the adverse effects of radiation. The model incorporated a lifetime horizon to estimate outcomes in terms of quality-adjusted life-years (QALYs) and costs from the perspective of the NHS.

RESULTS

Three studies met the inclusion criteria for the review. Two studies compared EOS with film X-ray and one study compared EOS with CR. The three included studies were small and of limited quality. One study used an earlier version of the technology, the Charpak system. Both studies comparing EOS with film X-ray found image quality to be comparable or better with EOS overall. Radiation dose was considerably lower with EOS: ratio of means for posteroanterior spine was 5.2 (13.1 for the study using the Charpak system); ratio of means for the lateral spine was 6.2 (15.1 for the study using the Charpak system). The study comparing EOS with CR found image quality to be comparable or better with EOS. Radiation dose was considerably lower with EOS than CR; ratio of means for the centre of the back was 5.9 and for the proximal lateral point 8.8. The lowest ratio of means was at the nape of the neck, which was 2.9. No other outcomes were assessed in the included studies, such as implications for patient management from the nature and quality of the image. Patient throughput is the major determinant of the cost-effectiveness of EOS. The average cost per procedure of EOS decreases with utilisation. Using estimates of patient throughput at national level from Hospital Episode Statistics data suggests that EOS is not cost-effective for the indications considered. Throughput in the region of 15,100 to 26,500 (corresponding to a workload of 60 to 106 patient appointments per working day) for EOS compared with a throughput of only 7530 for CR (30 patient appointments per working day) is needed to achieve an incremental cost-effectiveness ratio of £30,000 per QALY. EOS can be shown to be cost-effective only when compared with CR if the utilisation for EOS is about double the utilisation of CR.

LIMITATIONS

The main limitation of the systematic review of the clinical effectiveness of EOS was the limited number and quality of the data available. In particular, there were no studies assessing the potential health benefits arising from the quality and nature of the image, over and above those associated with reduced radiation exposure. Uncertainty in the model inputs was not fully explored owing to a lack of reporting of standard deviations or confidence intervals in the published literature for most of the parameters. As a result, uncertainty in the cost-effectiveness results was not presented.

CONCLUSIONS

Radiation dose is considerably lower with EOS than standard X-ray, whereas image quality remains comparable or better with EOS. However, the long-term health benefits from reduced radiation exposure with EOS are very small and there was a lack of data on other potential patient health benefits. The implications of any changes in the quality and nature of the EOS image compared with standard X-ray, for patient health outcomes, needs to be assessed. Given the higher cost of an EOS machine, utilisation is the major determinant of cost-effectiveness. Estimates of patient throughput at national level suggest that EOS is not cost-effective.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Assessment of fludarabine plus cyclophosphamide for patients with chronic lymphocytic leukaemia (the LRF CLL4 Trial): a randomised controlled trial

BACKGROUND

Previous studies of patients with chronic lymphocytic leukaemia reported high response rates to fludarabine combined with cyclophosphamide. We aimed to establish whether this treatment combination provided greater survival benefit than did chlorambucil or fludarabine.

METHODS

777 patients with chronic lymphocytic leukaemia requiring treatment were randomly assigned to fludarabine (n=194) or fludarabine plus cyclophosphamide (196) for six courses, or chlorambucil (387) for 12 courses. The primary endpoint was overall survival, with secondary endpoints of response rates, progression-free survival, toxic effects, and quality of life. Analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number NCT 58585610.

FINDINGS

There was no significant difference in overall survival between patients given fludarabine plus cyclophosphamide, fludarabine, or chlorambucil. Complete and overall response rates were better with fludarabine plus cyclophosphamide than with fludarabine (complete response rate 38%vs 15%, respectively; overall response rate 94%vs 80%, respectively; p<0.0001 for both comparisons), which were in turn better than with chlorambucil (complete response rate 7%, overall response rate 72%; p=0.006 and 0.04, respectively). Progression-free survival at 5 years was significantly better with fludarabine plus cyclophosphamide (36%) than with fludarabine (10%) or chlorambucil (10%; p<0.00005). Fludarabine plus cyclophosphamide was the best combination for all ages, including patients older than 70 years, and in prognostic groups defined by immunoglobulin heavy chain gene (V(H)) mutation status and cytogenetics, which were tested in 533 and 579 cases, respectively. Patients had more neutropenia and days in hospital with fludarabine plus cyclophosphamide, or fludarabine, than with chlorambucil. There was less haemolytic anaemia with fludarabine plus cyclophosphamide (5%) than with fludarabine (11%) or chlorambucil (12%). Quality of life was better for responders, but preliminary analyses showed no significant difference between treatments. A meta-analysis of these data and those of two published phase III trials showed a consistent benefit for the fludarabine plus cyclophosphamide regimen in terms of progression-free survival.

INTERPRETATION

Fludarabine plus cyclophosphamide should now become the standard treatment for chronic lymphocytic leukaemia and the basis for new protocols that incorporate monoclonal antibodies.

Two-view mammography at the incident round has improved the rate of screen-detected breast cancer in Wales

AIM

To investigate whether pre-invasive and invasive cancer detection rates were improved in Wales after the introduction of two views at incident screens.

METHODS

The records of women attending follow-up screening for 2 years before and 2 years after the introduction of two-view incident screening were analysed. Cancer detection rates were compared before and after introduction of two view screening.

RESULTS

At the incident round 98,752 women had one and 95,464 had two views. Five hundred and fifty-five cancers were detected with one view and 744 with two, an increased detection rate from 5.6 to 7.8 cancers per 1000 women screened (p=0.01). Two hundred and thirty-nine small cancers were detected with one view and 323 with two, increasing the detection rate from 2.4 to 3.4 per 1000 women screened (p=0.05).

CONCLUSIONS

Two-view mammography at incident rounds detects more cancers and more favourable prognosis small cancers than single-view mammograms.

Small Cell Lung Cancer Treated in Southeast Wales

AIMS

In small cell lung cancer (SCLC), consolidation thoracic irradiation (CTI) increases 3-year absolute survival by 5.4% in patients with limited disease and a complete response to chemotherapy. Early concurrent thoracic radiotherapy has been shown to improve local control and prolong survival compared with CTI in some trials. The standard management of patients with SCLC in southeast Wales is CTI in individuals with limited disease and a complete response to chemotherapy. A review of patients with SCLC was carried out to establish whether survival locally is comparable with that reported in published studies, and if patients given CTI have survival comparable with that reported in studies where early concurrent thoracic radiotherapy was used.

MATERIALS AND METHODS

Between January 2000 and December 2002, 303 patients were registered with SCLC in southeast Wales. One hundred and fifteen (47%) patients had limited disease and 60/115 (52%) received CTI.

RESULTS

Patients with limited disease receiving CTI had a median survival of 17.7 months (95% confidence interval: 15-27.9 months). The 2- and 5-year survivals were 38 and 13%, respectively.

CONCLUSIONS

These results compare favourably with previously published studies on SCLC. There are no plans to change our current treatment policy for SCLC in southeast Wales.

Enzymes of drug metabolism during delirium

BACKGROUND

Delirium is common in ill medical patients. Several drugs and polypharmacy are recognised risk factors, yet little is known about drug metabolism in people with delirium.

OBJECTIVE

The aim of this study was to investigate the activities of plasma esterases (drug metabolising enzymes) in delirium.

DESIGN

This was a prospective study of delirium present at time of hospital admission (community acquired) or developing later (hospital acquired) in patients admitted as a medical emergency and aged 75 years or over.

METHODS

Following informed consent or assent cognitive screening was completed on all patients on admission and every 48 hours subsequently. Delirium was diagnosed by Confusion Assessment Method and DSM IV criteria. Blood samples were taken on admission and at onset of delirium if this was later. Four plasma esterase assays were performed spectrophotometrically: acetylcholinesterase, aspirin esterase, benzoylcholinesterase, butyrylcholinesterase.

RESULTS

283 patients (71% of eligible) were recruited, with mean age 82.4 years and 59% female. 27% had community acquired delirium, 10% developed hospital acquired delirium, 63% never developed delirium. On admission the mean activities of all four esterase assays were statistically significantly lower in delirious than non delirious patients. There were no significant differences on admission in any plasma esterase activity between patients with hospital and community acquired delirium. In-hospital mortality was associated with low plasma esterase activities on admission.

CONCLUSION

Plasma esterase activities are suppressed during delirium. These data reinforce the need for extreme caution with drugs in this vulnerable population.

Single vs. dual vessel porcine extracorporeal liver perfusion

BACKGROUND

The use of porcine extracorporeal liver perfusion (PECLP) to provide temporary hepatic support for patients in fulminant hepatic failure has been limited by the fact that individual perfusions can be sustained for only a few hours. Inadequate liver function and/or hemodynamic instability are the major contributing factors for early interruption of PECLP. Recent reports suggest that the choice of single (portal vein only) vs dual (portal vein and hepatic artery) vessel perfusion may influence the duration of perfusion. We hypothesize that PECLP with single vessel perfusion (SVP) is associated with worse liver function and greater hemodynamic instability than PECLP with dual vessel perfusion (DVP).

MATERIALS AND METHODS

To eliminate the potentially confounding influences of liver failure and xenograft rejection, liver isografts procured from White-Landrace pig donors were perfused by either SVP or DVP via an extracorporeal circuit established with normal White-Landrace pig recipients. The function of perfused livers was evaluated by measuring production of bile and Factors V and VIII, clearance of ammonia and lactate, and extraction of O(2) at baseline and at 0, 1, 3, 6, 12, and 24 h after initiation of PECLP. The impact of PECLP on recipient hemodynamic status was assessed by monitoring BP, heart rate, urine output, O(2) saturation, etc. Among other parameters evaluated were serum albumin and total protein and hepatic release of IL-1beta and nitric oxide to assess their possible contributions to hemodynamic instability.

RESULTS

DVP and SVP livers cleared ammonia and lactate similarly. Both approaches were associated with progressive hypoalbuminemia and hypoproteinemia. DVP livers produced more bile and Factor V and were associated with less recipient hypotension and IL-1beta and NO release than SVP livers.

CONCLUSIONS

Livers with DVP function better than livers with SVP. The duration of PECLP can be limited by recipient hypotension, although this complication is less severe with DVP than with SVP.

Outcome in fracture healing: a review

This editorial reviews outcome measures in fracture healing. Individually radiological and clinical methods are inaccurate, but together provide a good indicator in clinical practice when a fracture has healed. Other quantitative methods are not practical. Vibrational analysis of fracture healing is complex and limited to research at present. Indirect fracture stiffness measurement is possible and has been used in clinical trials. Pin loosening reduces accuracy. The measurement of direct fracture stiffness has been validated and using this a decrease in re-fracture rate and a reduction of time to independent weight bearing (on average 3 weeks) was found. The system is accurate and simple to use in the clinical setting and allows the rate of healing to be monitored in fractures. Studies using poor outcome measures should be interpreted with care. The study of healing fractures is no exception.

Calcium-induced flexibility changes in the troponin C-troponin I complex

The contraction of vertebrate striated muscle is modulated by Ca(2+) binding to the regulatory protein troponin C (TnC). Ca(2+) binding causes conformational changes in TnC which alter its interaction with the inhibitory protein troponin I (TnI), initiating the regulatory process. We have used the frequency domain method of fluorescence resonance energy transfer (FRET) to measure distances and distance distributions between specific sites in the TnC-TnI complex in the presence and absence of Ca(2+) or Mg(2+). Using sequences based on rabbit skeletal muscle proteins, we prepared functional, binary complexes of wild-type TnC and a TnI mutant which contains no Cys residues and a single Trp residue at position 106 within the TnI inhibitory region. We used TnI Trp-106 as the FRET donor, and we introduced energy acceptor groups into TnC by labeling at Met-25 with dansyl aziridine or at Cys-98 with N-(iodoacetyl)-N'-(1-sulfo-5-naphthyl)ethylenediamine. Our distance distribution measurements indicate that the TnC-TnI complex is relatively rigid in the absence of Ca(2+), but becomes much more flexible when Ca(2+) binds to regulatory sites in TnC. This increased flexibility may be propagated to the whole thin filament, helping to release the inhibition of actomyosin ATPase activity and allowing the muscle to contract. This is the first report of distance distributions between TnC and TnI in their binary complex.

Patients' and providers' perceptions of outpatient treatment termination in a managed behavioral health organization

OBJECTIVE

A common complaint about managed care is that treatment decisions of patients and providers are frequently altered by concurrent review of ongoing outpatient treatment. The objective of this study was to examine this perception from the perspectives of patients and providers.

METHODS

A total of 190 patients and their providers were surveyed about the reason that outpatient treatment was terminated. The sample was randomly drawn from completed outpatient treatment episodes of a large national managed behavioral health organization.

RESULTS

In more than three-quarters of the cases, outpatient treatment ended because patients and providers agreed that treatment goals were partially or completely met. Only 5 percent of patients and 3 percent of providers said that treatment ended because the managed care organization denied ongoing treatment. Agreement between patient-provider pairs was generally poor regarding the perceived reason for termination, except when termination was attributed to concurrent review by the managed behavioral health organization.

CONCLUSIONS

In this study of a single large managed behavioral health organization, outpatient treatment was most likely to end based on the decisions of patients and providers rather than utilization review decisions.

Isolation of U(VI) reduction-deficient mutants of Shewanella putrefaciens

A U(VI) reduction-deficient mutant (Urr) screening technique was developed and combined with chemical mutagenesis procedures to identify a Urr mutant of Shewanella putrefaciens strain 200. The Urr mutant lacked the ability to grow anaerobically on U(VI) and NO(2)(-), yet retained the ability to grow anaerobically on eight other compounds as terminal electron acceptor. All 11 members of previously isolated sets of Fe(III) and Mn(IV) reduction-deficient mutants of S. putrefaciens 200 displayed Urr-positive phenotypes with the Urr screen and were capable of anaerobic growth on U(VI). This is the first reported isolation of a respiratory mutant that is unable to grow anaerobically on U(VI) as terminal electron acceptor.

Involvement of conserved, acidic residues in the N-terminal domain of troponin C in calcium-dependent regulation

We have mutated eight conserved, charged amino acid residues in the N-terminal, regulatory domain of troponin C (TnC) so we could investigate their role in troponin-linked Ca2+ regulation of muscle contraction. These residues surround a hydrophobic pocket in the N-terminal domain of TnC which, when Ca2+ binds to regulatory sites in this domain, is exposed and interacts with the inhibitory region of troponin I (TnI). We constructed three double mutants (E53A/E54A, E60A/E61A, and E85A/D86A) and two single mutants (R44A and R81A) of rabbit fast skeletal muscle troponin C (TnC) in which the charged residues were replaced with neutral alanines. All five of these mutants retained TnC's ability to bind TnI in a Ca2+-dependent manner, to neutralize TnI's inhibition of actomyosin S1 ATPase activity, and to form a ternary complex with TnI and troponin T (TnT). Ternary complexes formed with TnC(R44A) or TnC(R81A) regulated actomyosin S1 ATPase activity normally, with TnI-based inhibition in the absence of Ca2+ and TnT-based activation in the presence of Ca2+. TnC(E53A/E54A) and TnC(E85A/D86A) interacted weakly with TnT, as judged by native gel electrophoresis. Ternary complexes formed with these mutants inhibited actomyosin S1 ATPase activity in both the presence and absence of Ca2+, and did not undergo Ca2+-dependent structural changes in TnI which can be detected by limited chymotryptic digestion. TnC(E60A/E61A) interacted normally with TnT. Its ternary complex showed Ca2+-dependent structural changes in TnI, inhibited actomyosin S1 ATPase in the absence of Ca2+, but did not activate ATPase in the presence of Ca2+. This is the first demonstration that selective mutation of TnC can abolish the activating effect of troponin while its inhibitory function is retained. Our results suggest the existence of an elaborate network of protein-protein interactions formed by TnI, TnT, and the N-terminal domain of TnC, all of which are important in the Ca2+-dependent regulation of muscle contraction.

Ca2+-dependent interaction of the inhibitory region of troponin I with acidic residues in the N-terminal domain of troponin C

Ca2+ regulation of vertebrate striated muscle contraction is initiated by conformational changes in the N-terminal, regulatory domain of the Ca2+-binding protein troponin C (TnC), altering the interaction of TnC with the other subunits of troponin complex, TnI and TnT. We have investigated the role of acidic amino acid residues in the N-terminal, regulatory domain of TnC in binding to the inhibitory region (residues 96-116) of TnI. We constructed three double mutants of TnC (E53A/E54A, E60A/E61A and E85A/D86A), in which pairs of acidic amino acid residues were replaced by neutral alanines, and measured their affinities for synthetic inhibitory peptides. These peptides had the same amino acid sequence as TnI segments 95-116, 95-119 or 95-124, except that the natural Phe-100 of TnI was replaced by a tryptophan residue. Significant Ca2+-dependent increases in the affinities of the two longer peptides, but not the shortest one, to TnC could be detected by changes in Trp fluorescence. In the presence of Ca2+, all the mutant TnCs showed about the same affinity as wild-type TnC for the inhibitory peptides. In the presence of Mg2+ and EGTA, the N-terminal, regulatory Ca2+-binding sites of TnC are unoccupied. Under these conditions, the affinity of TnC(E85A/D86A) for inhibitory peptides was about half that of wild-type TnC, while the other two mutants had about the same affinity. These results imply a Ca2+-dependent change in the interaction of TnC Glu-85 and/or Asp-86 with residues (117-124) on the C-terminal side of the inhibitory region of TnI. Since Glu-85 and/or Asp-86 of TnC have also been demonstrated to be involved in Ca2+-dependent regulation through interaction with TnT, this region of TnC must be critical for troponin function.

RNA oxidation is a prominent feature of vulnerable neurons in Alzheimer's disease

In this study we used an in situ approach to identify the oxidized nucleosides 8-hydroxydeoxyguanosine (8OHdG) and 8-hydroxyguanosine (8OHG), markers of oxidative damage to DNA and RNA, respectively, in cases of Alzheimer's disease (AD). The goal was to determine whether nuclear and mitochondrial DNA as well as RNA is damaged in AD. Immunoreactivity with monoclonal antibodies 1F7 or 15A3 recognizing both 8OHdG and 8OHG was prominent in the cytoplasm and to a lesser extent in the nucleolus and nuclear envelope in neurons within the hippocampus, subiculum, and entorhinal cortex as well as frontal, temporal, and occipital neocortex in cases of AD, whereas similar structures were immunolabeled only faintly in controls. Relative density measurement showed that there was a significant increase (p < 0.0001) in 8OHdG and 8OHG immunoreactivity with 1F7 in cases of AD (n = 22) as compared with senile (n = 13), presenile (n = 10), or young controls (n = 4). Surprisingly, the oxidized nucleoside was associated predominantly with RNA because immunoreaction was diminished greatly by preincubation in RNase but only slightly by DNase. This is the first evidence of increased RNA oxidation restricted to vulnerable neurons in AD. The subcellular localization of damaged RNA showing cytoplasmic predominance is consistent with the hypothesis that mitochondria may be a major source of reactive oxygen species that cause oxidative damage in AD.

Comparative kinetic analysis of FLP and cre recombinases: mathematical models for DNA binding and recombination

The integrase class site specific recombinases FLP from Saccharomyces cerevisiae, and Cre from bacteriophage P1, have been extensively used to direct DNA rearrangements in heterologous organisms. Although their reaction mechanisms have been relatively well characterised, little comparative analysis of the two enzymes has been published. We present a comparative kinetic analysis of FLP and Cre, which identifies important differences. Gel mobility shift assays show that Cre has a higher affinity for its target, loxP (7. 4x10(10) M-1), than FLP for its target, FRT (8.92x10(8) M-1). We show that both recombinases bind the two halves of their target sites cooperatively, and that Cre shows approximately threefold higher cooperativity than FLP. Using a mathematical model describing the sequential binding of recombinase monomers to DNA, we have determined values for the association and dissociation rate constants for FLP and Cre.FLP and Cre also showed different characteristics in in vitro recombination assays. In particular, approximately tenfold more active FLP was required than Cre to optimally recombine a given quantity of excision substrate. FLP was able to reach maximum excision levels approaching 100%, whilst Cre-mediated excision did not exceed 75%. To investigate possible reasons for these differences a mathematical model describing the excision recombination reaction was established. Using measured DNA binding parameters for FLP and Cre in the model, and comparing simulated and experimental recombination data, the values of the remaining unknown parameters were determined. This analysis indicates that the synaptic complex is more stable for Cre than for FLP.

The sarcoplasmic reticulum Ca2+ pump: inhibition by thapsigargin and enhancement by adenovirus-mediated gene transfer

The role of the sarcoplasmic reticulum Ca2+ pump in the excitation-contraction coupling of cardiac muscle fibers was evaluated in experiments on SR ATPase inhibition with thapsigargin or, alternatively, on Ca2+ pump enhancement by SR ATPase transgenic expression. We found that thapsigargin, a highly specific and potent inhibitor of the SR ATPase, produces a strong reduction of cytosolic Ca2+ transient and contractile activation in neonatal rat myocytes, in the absence of any other functional effect. On the other hand, Ca2+ pump enhancement by ATPase transgenic expression affects dramatically Ca2+ transient and twitches, resulting in shorter duration and more rapid decay rates. Of particular interest is gene transfer mediated by recombinant adenovirus vectors under control of a cell-specific promoter, resulting in transgenic expression of all myocytes in culture, and no expression in fibroblasts.

The motivation to learn: efficacy and relevance of the Oswestry postgraduate orthopaedic training programme

The efficacy and relevance of medical education has come under increased scrutiny in recent years. The shortening of basic surgical training and the introduction of 'seamless' higher surgical training has placed greater emphasis on the quality of education provided/facilitated by trainers. Additionally, study leave budgets are under increasing pressure from trainees wishing to attend courses or conferences, and regional postgraduate deans who wish to see a proportionally greater amount of training on an 'in-house' basis. Against this background we have reviewed the learning opportunities available on the Oswestry postgraduate programme to see if these opportunities provide adequate motivation to learn for the trainee.

Sublytic terminal complement attack on myotubes decreases the expression of mRNAs encoding muscle-specific proteins

Activation of inflammatory and cytotoxic complement effectors that include the C5b-9 complex plays an important pathogenic role in myasthenia gravis, an inflammatory autoimmune disease of the muscle. Altered muscle-specific gene expression has been observed in experimental myasthenic rats. In this study, we have examined the effect of sublytic C5b-9 on myotubes differentiated from C2C12 myoblasts, by generating C5b-9 with C7-deficient serum with or without C7. Within 2 h, C7-deficient serum plus C7, compared with C7-deficient serum alone, induced markedly decreased levels of mRNAs encoding alpha-actin, troponin I slow twitch isoform, acetylcholine receptor alpha, and muscle aldolase A, whereas the heat shock protein 83 mRNA level remained constant, by northern analysis. Because the half-life of the acetylcholine receptor alpha was estimated to be > 8 h, the C5b-9 effect was, in part, due to enhanced mRNA decay. Because C5b-9 also induced c-jun mRNA and reduced the myoD mRNA level, a possible inhibition of muscle gene transcription by C5b-9 was examined in myotubes transfected with troponin promoter-luciferase gene constructs. Luciferase activity was reduced to 50% in response to C5b-9 at 2 h. Thus, C5b-9 appears to inhibit the muscle-specific gene expression by stimulating mRNA decay and by decreasing the transcription process. The data also indicate a possible pathogenic role of C5b-9 in immune-mediated inflammatory muscle disorders in which complement activation has been implicated.

Isolation and characterization of an avian slow myosin heavy chain gene expressed during embryonic skeletal muscle fiber formation

We have isolated and begun characterization of the quail slow myosin heavy chain (MyHC) 3 gene, the first reported avian slow MyHC gene. Expression of slow MyHC 3 in skeletal muscle is restricted to the embryonic period of development, when the fiber pattern of future fast and slow muscle is established. In embryonic hindlimb development, slow MyHC 3 gene expression coincides with slow muscle fiber formation as distinguished by slow MyHC-specific antibody staining. In addition to expression in embryonic appendicular muscle, slow MyHC 3 is expressed continuously in the atria. Transfection of slow MyHC 3 promoter-reporter constructs into embryonic myoblasts that form slow MyHC-expressing fibers identified two regions regulating expression of this gene in skeletal muscle. The proximal promoter, containing potential muscle-specific regulatory motifs, permits expression of a reporter gene in embryonic slow muscle fibers, while a distal element, located greater than 2600 base pairs upstream, further enhances expression 3-fold. The slow muscle fiber-restricted expression of slow MyHC 3 during embryonic development, and expression of slow MyHC 3 promoter-reporter constructs in embryonic muscle fibers in vitro, makes this gene a useful marker to study the mechanism establishing the slow fiber lineage in the embryo.

Use of thapsigargin to study Ca2+ homeostasis in cardiac cells

Several reports have documented that thapsigargin is a potent inhibitor of the SR Ca2+ ATPase isolated from cardiac or skeletal muscle. We have characterized the specificity of this agent in intact rat cardiac myocytes using cells maintained in the whole cell voltage clamp configuration. We have shown that thapsigargin decreases the magnitude of the Ca2+ transient and the twitch by about 80% while it slows the decay rate for these responses. These changes were not accompanied by any alterations in sarcolemmal currents or in the trigger Ca2+ generated by the inward calcium current. Taken together these results reveal that the action of thapsigargin is restricted to the SR Ca2+ ATPase in intact cardiac myocytes. Furthermore, it is demonstrated unambiguously that SR intracellular Ca2+ stores are an absolute requirement for the development of contractile tension in rat heart myocytes. It is shown that thapsigargin is a valuable probe to examine the importance of SR pools of Ca2+ and the role of the Ca2+ ATPase in intact myocytes as well as in genetically altered heart cells.

Voltage-dependent calcium channel beta-subunits in combination with alpha 1 subunits, have a GTPase activating effect to promote the hydrolysis of GTP by G alpha o in rat frontal cortex

The dihydropyridine-sensitive calcium channel agonist (-)-BayK 8644 was found to produce an enhancement of the intrinsic hydrolysis of GTP by Go in rat frontal cortex membranes. An anti-calcium channel beta-subunit antiserum abolished the (-)-BayK 8644-stimulated hydrolysis of GTP by Go and reduced the dihydropyridine binding capacity of the cortical membranes. A peptide which mimics the beta-subunit binding domain of the calcium channel complex, also attenuated (-)-BayK 8644 activation of GTPase. This study suggests that the calcium channel beta-subunit is the principal component of the channel complex involved in linking dihydropyridine agonist binding to enhanced hydrolysis of GTP by Go. This may be a mechanism by which calcium channels can normally act to limit the duration of a G-protein modulatory signal.

Calcium-induced troponin flexibility revealed by distance distribution measurements between engineered sites

The contraction of vertebrate striated muscle is regulated by Ca2+ binding to troponin C (TnC). This causes conformational changes which alter the interaction of TnC with the inhibitory protein TnI and the tropomyosin-binding protein TnT. We have used the frequency domain method of fluorescence resonance energy transfer to measure TnT-TnC and TnT-TnI distances and distance distributions, in the presence of Ca2+, Mg2+, or EGTA, in TnC.TnI.TnT complexes. We reconstituted functional, ternary troponin complexes using the following recombinant subunits whose sequences were based on those of rabbit skeletal muscle: wild-type TnC; TnT25, a mutant C-terminal 25-kDa fragment of TnT containing a single Trp212 which was used as the sole donor for fluorescence energy transfer measurements; Trp-less TnI mutants which contained either no Cys or a single Cys at position 9, 96, or 117. Energy acceptor groups were introduced into TnC or TnI by labeling with dansyl aziridine or N-(iodoacetyl)-N'-(1-sulfo-5-naphthyl)ethylenediamine. Our results indicate that the troponin complex is relatively rigid in relaxed muscle, but becomes much more flexible when Ca2+ binds to regulatory sites in TnC. This increased flexibility may be propagated to the whole thin filament, releasing the inhibition of actomyosin ATPase activity and allowing the muscle to contract. This is the first report of distance distribution measurements between troponin subunits.

Delineation of a slow-twitch-myofiber-specific transcriptional element by using in vivo somatic gene transfer

Contractile proteins are encoded by multigene families, most of whose members are differentially expressed in fast- versus slow-twitch myofibers. This fiber-type-specific gene regulation occurs by unknown mechanisms and does not occur within cultured myocytes. We have developed a transient, whole-animal assay using somatic gene transfer to study this phenomenon and have identified a fiber-type-specific regulatory element within the promoter region of a slow myofiber-specific gene. A plasmid-borne luciferase reporter gene fused to various muscle-specific contractile gene promoters was differentially expressed when injected into slow- versus fast-twitch rat muscle: the luciferase gene was preferentially expressed in slow muscle when fused to a slow troponin I promoter, and conversely, was preferentially expressed in fast muscle when fused to a fast troponin C promoter. In contrast, the luciferase gene was equally well expressed by both muscle types when fused to a nonfiber-type-specific skeletal actin promoter. Deletion analysis of the troponin I promoter region revealed that a 157-bp enhancer conferred slow-muscle-preferential activity upon a minimal thymidine kinase promoter. Transgenic analysis confirmed the role of this enhancer in restricting gene expression to slow-twitch myofibers. Hence, somatic gene transfer may be used to rapidly define elements that direct myofiber-type-specific gene expression prior to the generation of transgenic mice.

Developmental regulation of troponin I isoform genes in striated muscles of transgenic mice

The differentiation and diversification of striated muscle is a complex process involving numerous temporal and spatial alterations in the pattern of contractile protein isoform gene expression. In order to gain insight into the regulation of contractile protein isoform changes during skeletal and cardiac muscle formation, the expression of a transgene comprising a chloramphenicol acetyltransferase (CAT) reporter gene linked with sequences from -4200 to +12 of the human slow skeletal troponin I (TnIs) gene, and all three endogenous mouse troponin I (TnI) isoform genes, was investigated in embryonic, neonatal, and postnatal mice. The -4200 TnIsCAT transgene was properly activated in the limb and trunk skeletal muscle primordia and the early embryonic atrium and ventricle of the heart. Along with the endogenous mouse TnIs gene, expression of the CAT transgene began to segregate into the presumptive slow-twitch myofibers at late fetal stages and expression declined in the neonatal and postnatal heart except for the conductive tissues, in which expression persisted into adulthood. However, expression of the CAT transgene during development did not completely follow the endogenous mouse TnIs gene. The expression of the CAT transgene was aberrantly low in the embryonic cardiac outflow tract and the ventricles of the fetal heart. In addition to its expression in striated muscles, the transgene was expressed aberrantly in the primordial axial skeleton. We conclude that the upstream sequences from the human TnIs gene contain sufficient regulatory information to confer appropriate transgene expression during the early differentiation of skeletal muscles and during the establishment of fiber type upon the maturation of myofibers. However, additional regulatory elements are likely to be required for correct temporal and spatial regulation in the heart and somitic mesoderm during development. In vitro DNA transfection of cultured skeletal and cardiac muscle cells identified a cell type-specific enhancer element within the first intron of the TnIs gene whose absence in the transgene may account for the aberrant expression observed in vivo. In addition, we provide the first evidence that the fast-twitch skeletal muscle isoform of troponin I, TnIf, is transiently expressed during early cardiac muscle development.

Fetal hepatosplenomegaly associated with transient myeloproliferative disorder in trisomy 21

The in utero diagnosis of fetal myeloproliferative disease was made by cordocentesis following the ultrasound appearance of fetal hepatosplenomegaly and mild hydrops. The 2 fetuses reported both had leukocyte counts greater than 75,000/mm3 with a predominance of blast forms. In both cases the karyotype revealed trisomy 21.