A dynamic time-to-event model for prediction of acute graft-versus-host disease in patients after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Acute graft-versus-host disease (aGvHD) is a major cause of death for patients following allogeneic hematopoietic stem cell transplantation (HSCT). Effective management of moderate to severe aGvHD remains challenging despite recent advances in HSCT, emphasizing the importance of prophylaxis and risk factor identification.

METHODS

In this study, we analyzed data from 1479 adults who underwent HSCT between 2005 and 2017 to investigate the effects of aGvHD prophylaxis and time-dependent risk factors on the development of grades II-IV aGvHD within 100 days post-HSCT.

RESULTS

Using a dynamic longitudinal time-to-event model, we observed a non-monotonic baseline hazard overtime with a low hazard during the first few days and a maximum hazard at day 17, described by Bateman function with a mean transit time of approximately 11 days. Multivariable analysis revealed significant time-dependent effects of white blood cell counts and cyclosporine A exposure as well as static effects of female donors for male recipients, patients with matched related donors, conditioning regimen consisting of fludarabine plus total body irradiation, and patient age in recipients of grafts from related donors on the risk to develop grades II-IV aGvHD. Additionally, we found that higher cumulative hazard on day 7 after allo-HSCT are associated with an increased incidence of grades II-IV aGvHD within 100 days indicating that an individual assessment of the cumulative hazard on day 7 could potentially serve as valuable predictor for later grades II-IV aGvHD development. Using the final model, stochastic simulations were performed to explore covariate effects on the cumulative incidence over time and to estimate risk ratios.

CONCLUSION

Overall, the presented model showed good descriptive and predictive performance and provides valuable insights into the interplay of multiple static and time-dependent risk factors for the prediction of aGvHD.

Time-dependent prediction of mortality and cytomegalovirus reactivation after allogeneic hematopoietic cell transplantation using machine learning

Allogeneic hematopoietic cell transplantation (HCT) effectively treats high-risk hematologic diseases but can entail HCT-specific complications, which may be minimized by appropriate patient management, supported by accurate, individual risk estimation. However, almost all HCT risk scores are limited to a single risk assessment before HCT without incorporation of additional data. We developed machine learning models that integrate both baseline patient data and time-dependent laboratory measurements to individually predict mortality and cytomegalovirus (CMV) reactivation after HCT at multiple time points per patient. These gradient boosting machine models provide well-calibrated, time-dependent risk predictions and achieved areas under the receiver-operating characteristic of 0.92 and 0.83 and areas under the precision-recall curve of 0.58 and 0.62 for prediction of mortality and CMV reactivation, respectively, in a 21-day time window. Both models were successfully validated in a prospective, non-interventional study and performed on par with expert hematologists in a pilot comparison.

Challenges and Pitfalls for Implementing Digital Health Solutions in Clinical Studies in Europe

The increasing number of digital solutions developed for use in clinical health care settings is accompanied by new challenges to develop and conduct clinical studies that include eHealth technologies. Clinical study implementation plans often disregard or underestimate the necessity of additional administrative and logistic tasks required at clinical sites as well as ethical aspects to test digital solutions. Experiences made in the run-up of an observational clinical feasibility study at three international clinical sites in the framework of the MyPal project (https://mypal-project.eu/) result in recommendations to avoid delays and barriers in the planning of such prospective studies in clinical and also palliative care for increased efficiency.

Ultrasound Evaluation for Incomplete Carpal Tunnel Release

Background: Ultrasound can provide evaluation of the anatomy of the carpal tunnel in a convenient, noninvasive office setting. This study is intended to determine the accuracy and diagnostic performance of ultrasound, used by surgeons, for the evaluation of completeness of carpal tunnel release (CTR). Methods: Ten cadaver arms underwent randomized sectioning of 0%, 25%, 50%, 75%, or 100% of the transverse carpal ligament. Following a brief training session, a blinded observer used ultrasound to evaluate the percentage of the transverse carpal ligament release. The release amount was then confirmed with an open exposure of the transverse carpal ligament. Results: Cronbach α and Pearson correlation coefficients were 0.92 and 0.87, demonstrating excellent reliability and validity of the technique. Diagnostic performance including sensitivity, specificity, positive predictive value, and negative predictive value was 100%, 75%, 86%, and 100%, respectively, for the diagnosis of incomplete release of the transverse carpal ligament by a novice sonographer orthopedic surgeon. Conclusions: The ultrasound is a highly accurate tool for the diagnosis of incomplete transverse carpal ligament release and requires a minimal amount of training to use for this purpose. It provides a rapid means of diagnosing incomplete release of the transverse carpal ligament following CTR.

Benchmarking Wilms' tumor in multisequence MRI data: why does current clinical practice fail? Which popular segmentation algorithms perform well?

Wilms' tumor is one of the most frequent malignant solid tumors in childhood. Accurate segmentation of tumor tissue is a key step during therapy and treatment planning. Since it is difficult to obtain a comprehensive set of tumor data of children, there is no benchmark so far allowing evaluation of the quality of human or computer-based segmentations. The contributions in our paper are threefold: (i) we present the first heterogeneous Wilms' tumor benchmark data set. It contains multisequence MRI data sets before and after chemotherapy, along with ground truth annotation, approximated based on the consensus of five human experts. (ii) We analyze human expert annotations and interrater variability, finding that the current clinical practice of determining tumor volume is inaccurate and that manual annotations after chemotherapy may differ substantially. (iii) We evaluate six computer-based segmentation methods, ranging from classical approaches to recent deep-learning techniques. We show that the best ones offer a quality comparable to human expert annotations.

The relationship between therapist-rated function and patient-reported outcome measures

STUDY DESIGN

Prospective cohort study.

INTRODUCTION

Some third-party payers require hand therapists to rate patient's functional disability based on patient self-rating using patient-reported outcome measures (PROMs), objective measurements of impairment, and observation of functional tasks-hand therapist-rated function (HTRF).

PURPOSE OF THE STUDY

To test the correlation between HTRF and PROMs (upper limb functional index [ULFI] and Patient-Reported Outcomes Measurement Information System upper extremity [PROMIS UE]) and its association with psychological factors.

METHODS

In 2014, 100 new patients with upper extremity illness presenting to hand therapists were asked to participate in an observational cross-sectional study. Demographic-, condition-related, and psychological factors were obtained in addition to PROMs and HTRF.

RESULTS

HTRF correlated moderately with PROMIS UE (r = -0.49, P < .001) and ULFI (r = -0.56, P < .001). Correlation between PROMIS UE and ULFI was strong (r = 0.78, P < .001). Psychological factors explained most of the variations in both HTRF and PROMs.

CONCLUSIONS

Hand therapists' ratings of patient function correlate less strongly with PROMs than PROMs correlate with one other. The discrepancy between HTRF and PROMs may offer an opportunity to address stress, distress, or ineffective coping strategies that can interfere with recovery-an opportunity for therapists and patients to collaborate and develop goals and for future research to develop effective and feasible strategies for hand therapists.

LEVEL OF EVIDENCE

Level II, diagnostic study.

Cmr is a redox-responsive regulator of DosR that contributes to M. tuberculosis virulence

Mycobacterium tuberculosis (MTb) is the causative agent of pulmonary tuberculosis (TB). MTb colonizes the human lung, often entering a non-replicating state before progressing to life-threatening active infections. Transcriptional reprogramming is essential for TB pathogenesis. In vitro, Cmr (a member of the CRP/FNR super-family of transcription regulators) bound at a single DNA site to act as a dual regulator of cmr transcription and an activator of the divergent rv1676 gene. Transcriptional profiling and DNA-binding assays suggested that Cmr directly represses dosR expression. The DosR regulon is thought to be involved in establishing latent tuberculosis infections in response to hypoxia and nitric oxide. Accordingly, DNA-binding by Cmr was severely impaired by nitrosation. A cmr mutant was better able to survive a nitrosative stress challenge but was attenuated in a mouse aerosol infection model. The complemented mutant exhibited a ∼2-fold increase in cmr expression, which led to increased sensitivity to nitrosative stress. This, and the inability to restore wild-type behaviour in the infection model, suggests that precise regulation of the cmr locus, which is associated with Region of Difference 150 in hypervirulent Beijing strains of Mtb, is important for TB pathogenesis.

Novel drug targets in cell wall biosynthesis exploited by gene disruption in Pseudomonas aeruginosa

For clinicians, Pseudomonas aeruginosa is a nightmare pathogen that is one of the top three causes of opportunistic human infections. Therapy of P. aeruginosa infections is complicated due to its natural high intrinsic resistance to antibiotics. Active efflux and decreased uptake of drugs due to cell wall/membrane permeability appear to be important issues in the acquired antibiotic tolerance mechanisms. Bacterial cell wall biosynthesis enzymes have been shown to be essential for pathogenicity of Gram-negative bacteria. However, the role of these targets in virulence has not been identified in P. aeruginosa. Here, we report knockout (k.o) mutants of six cell wall biosynthesis targets (murA, PA4450; murD, PA4414; murF, PA4416; ppiB, PA1793; rmlA, PA5163; waaA, PA4988) in P. aeruginosa PAO1, and characterized these in order to find out whether these genes and their products contribute to pathogenicity and virulence of P. aeruginosa. Except waaA k.o, deletion of cell wall biosynthesis targets significantly reduced growth rate in minimal medium compared to the parent strain. The k.o mutants showed exciting changes in cell morphology and colonial architectures. Remarkably, ΔmurF cells became grossly enlarged. Moreover, the mutants were also attenuated in vivo in a mouse infection model except ΔmurF and ΔwaaA and proved to be more sensitive to macrophage-mediated killing than the wild-type strain. Interestingly, the deletion of the murA gene resulted in loss of virulence activity in mice, and the virulence was restored in a plant model by unknown mechanism. This study demonstrates that cell wall targets contribute significantly to intracellular survival, in vivo growth, and pathogenesis of P. aeruginosa. In conclusion, these findings establish a link between cell wall targets and virulence of P. aeruginosa and thus may lead to development of novel drugs for the treatment of P. aeruginosa infection.

Mallet Fractures of the Thumb Compared With Mallet Fractures of the Fingers

BACKGROUND

The purpose of this study was to look for differences in mechanism, radiographic findings, and treatment between mallet fractures of the thumb and mallet fractures of the index through small fingers.

METHODS

This retrospective study included 24 mallet fractures of the thumb and 392 mallet fractures of other digits. We compared demographics, injury factors (side, dominant hand, time between injury and first visit, and injury mechanism), subluxation, fragment size, treatment, and time from injury to final evaluation between the 2 groups.

RESULTS

Mallet fractures of the thumb presented for treatment sooner after injury (2.9 vs 13 days on average), had less fragment displacement (27% vs 33%), and less articular involvement (39% vs 46% on average). None of the mallet fractures of the thumb had radiographic evidence of subluxation, whereas 25% of mallet fractures of other fingers had initial or later subluxation.

CONCLUSIONS

Mallet fractures of the thumb are not likely to subluxate.

Factors associated with subluxation in mallet fracture

Radiographs and medical record of all adult patients with a mallet fracture in three hospitals between 2004 and 2014 were reviewed. International Classification of Diseases, Ninth Revision (ICD-9) codes and text search in radiographic reports were used to identify all acute patients with potential mallet fractures in our institutional database. Manually checking, 392 true mallet fractures were identified among them, 78 had subluxation at the time of diagnosis and 19 had subluxation at a later time point during treatment. Fragment size, fragment displacement, and interval between injury and treatment were associated with initial and late subluxation. Subluxation was not observed when the fracture size was less than 39% of the total articular surface. For each 1% increase in total articular surface involvement in fractures with more than 39% involvement, the risk of subluxation increased by 4% and for each 1% of displacement, the risk of subluxation increased by 4%.

LEVEL OF EVIDENCE

IV.

Mechanisms of intrinsic resistance and acquired susceptibility of Pseudomonas aeruginosa isolated from cystic fibrosis patients to temocillin, a revived antibiotic

The β-lactam antibiotic temocillin (6-α-methoxy-ticarcillin) shows stability to most extended spectrum β-lactamases, but is considered inactive against Pseudomonas aeruginosa. Mutations in the MexAB-OprM efflux system, naturally occurring in cystic fibrosis (CF) isolates, have been previously shown to reverse this intrinsic resistance. In the present study, we measured temocillin activity in a large collection (n = 333) of P. aeruginosa CF isolates. 29% of the isolates had MICs ≤ 16 mg/L (proposed clinical breakpoint for temocillin). Mutations were observed in mexA or mexB in isolates for which temocillin MIC was ≤512 mg/L (nucleotide insertions or deletions, premature termination, tandem repeat, nonstop, and missense mutations). A correlation was observed between temocillin MICs and efflux rate of N-phenyl-1-naphthylamine (MexAB-OprM fluorescent substrate) and extracellular exopolysaccharide abundance (contributing to a mucoid phenotype). OpdK or OpdF anion-specific porins expression decreased temocillin MIC by ~1 two-fold dilution only. Contrarily to the common assumption that temocillin is inactive on P. aeruginosa, we show here clinically-exploitable MICs on a non-negligible proportion of CF isolates, explained by a wide diversity of mutations in mexA and/or mexB. In a broader context, this work contributes to increase our understanding of MexAB-OprM functionality and help delineating how antibiotics interact with MexA and MexB.

The Association of Complementary Health Approaches With Mood and Coping Strategies Among Orthopedic Patients

Background: Variation in pain intensity and magnitude of disability among patients with musculoskeletal illness is largely accounted for by variations in symptoms of depression, catastrophic thinking, and heightened illness concern. It is possible that patients with greater stress, distress, and less effective coping strategies might be more likely to seek the use of Complementary Health Approaches (CHA). This study addressed the primary null hypothesis that there are no demographic, illness-related, or psychological factors associated with CHA use among patients with upper extremity illness. Methods: A cohort of 170 patients completed a web-based Complementary and Alternative Medicine (CAM) questionnaire the Patient Reported Outcomes Measurement Information System (PROMIS) Depression and Pain Interference questionnaires. We evaluated differences between patients who sought CAM treatment regarding the PROMIS Pain Interference and PROMIS Depression scores. Ninety-four patients (56%) use or plan to use CAM treatment. A CAM provider was consulted by 61 patients (37%): most commonly a massage therapist (30/61), chiropractor (26/61), or acupuncturist (14/61). Results: In bivariate analysis patients who sought CAM reported greater average PROMIS Pain Interference than those who did not. In multivariable logistic regression, CAM use was associated with a higher Pain Interference Score and the specific surgeon. Conclusion: In conclusion, CHA use is prevalent amongst orthopaedic patients and associated with less effective coping strategies. Orthopaedic surgeons might consider asking patients about CHA use and determining whether those patients are interested in cognitive behavioral therapy.

Swarming motility is modulated by expression of the putative xenosiderophore transporter SppR-SppABCD in Pseudomonas aeruginosa PA14

In the present study, we characterised the putative peptide ABC transporter SppABCD, which is co-transcribed with the TonB-dependent receptor SppR in Pseudomonas aeruginosa PA14. However, our data show that this transporter complex is not involved in the uptake of peptides. The fact that the TonB-dependent receptor SppR is regulated by an iron starvation ECF sigma factor suggested that this transporter is probably involved in the uptake of xenosiderophores. Therefore, we screened culture supernatants of 23 siderophore-producing bacteria for their ability to induce the expression of the SppR-regulating ECF sigma factor. However, none of them had an effect on the expression of this ECF sigma factor. Since the spp operon is not expressed under standard laboratory conditions, we overexpressed it from plasmids in PA14, which led to an impairment of its swarming motility on semisolid agar. Since we excluded the possibility that the uptake of a culture medium component was responsible for the observed phenotype, we hypothesize that the Spp transport system is involved in the uptake of a compound from the periplasmic space or a compound secreted by P. aeruginosa. Furthermore, we found that rhamnolipid synthesis was decreased while biofilm and exopolysaccharide synthesis was slightly increased upon overexpression of the spp operon. Moreover, we observed an impact of spp overexpression on regulation of genes involved in siderophore and phenazine biosynthesis.

Operative Versus Nonoperative Management of Nonfunctioning Pancreatic Neuroendocrine Tumors

INTRODUCTION

Surgical resection is the only curative treatment for pancreatic neuroendocrine tumors (PNETs), but pancreatic operations carry a significant morbidity. We investigated whether the resection of small, asymptomatic nonfunctioning PNETs is beneficial. Clinicopathologic factors were retrospectively reviewed for all PNET cases from 1998 to 2014.

METHODS

Kaplan-Meier survival and multivariable regression analyses were performed. A total of 249 patients had nonfunctioning PNETs with adequate follow-up, of whom 193 were resected and 56 were observed. Median age was 56 years, and 48 % of the patients were female.

RESULTS

Overall, the resected patients had a significantly longer survival (OS) (p = 0.001). However, for the patients with PNETs ≤2.5 cm in size and without metastasis at presentation, tumor size significantly modified the effect of resection on overall survival (p < 0.05). The protective effect of resection increased as tumor size increased. An operation became a significant predictor of overall survival for tumors >1.5 cm (p = 0.050 or less for larger tumors) but was not significant for tumors <1.5 cm (p = 0.317 or more for smaller tumors), controlling for age-adjusted Charlson comorbidity index.

CONCLUSION

Resection of nonfunctioning PNETs over 1.5 cm is independently and significantly associated with a longer survival. However, the benefit of resection for tumors under 1.5 cm is unclear.

What Factors are Associated With a Surgical Site Infection After Operative Treatment of an Elbow Fracture?

BACKGROUND

Surgical site infections are one of the more common major complications of elbow fracture surgery and can contribute to other adverse outcomes, prolonged hospital stays, and increased healthcare costs.

QUESTIONS/PURPOSES

We asked: (1) What are the factors associated with a surgical site infection after elbow fracture surgery? (2) When taking the subset of closed elbow fractures only, what are the factors associated with a surgical site infection? (3) What are the common organisms isolated from an elbow infection after open treatment?

METHODS

One thousand three hundred twenty adult patients underwent surgery for an elbow fracture between January 2002 and July 2014 and were included in our study. Forty-eight of 1320 patients (4%) had a surgical site infection develop. Thirty-four of 1113 patients with a closed fracture (3%) had a surgical site infection develop.

RESULTS

For all elbow fractures, use of plate and screw fixation (adjusted odds ratio [OR]= 2.2; 95% CI, 1.0-4.5; p = 0.041) and use of external fixation before surgery (adjusted OR = 4.7; 95% CI, 1.1-21; p = 0.035) were associated with higher infection rates. When subset analysis was performed for closed fractures, only smoking (adjusted OR = 2.2; 95% CI, 1.1-4.5; p = 0.023) was associated with higher infection rates. Staphylococcus aureus was the most common bacteria cultured (59%).

CONCLUSIONS

The only modifiable risk factor for a surgical site infection after open reduction and internal fixation was cigarette smoking. Plate fixation and temporary external fixation are likely surrogates for more complex injuries, therefore no recommendations should be inferred from this association. Surgeons should counsel patients who smoke.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Factors Associated With Reoperation After Fixation of Displaced Olecranon Fractures

BACKGROUND

Surgery for fixation of olecranon fractures is associated with reoperation, mostly for implant removal. A study of a large cohort of patients treated by many different surgeons allows us to determine if specific techniques or implants are associated with a higher rate of reoperation.

QUESTIONS/PURPOSES

After open reduction and internal fixation of isolated olecranon fractures, what factors are associated with (1) reoperation and (2) implant removal?

METHODS

Three hundred ninety-two adult patients who had operative treatment of a displaced olecranon fracture not associated with other fractures, dislocation, or subluxation at two area hospitals between January 2002 and May 2014 were analyzed to determine factors associated with reoperation. One hundred thirty-eight (35%) patients had plate and screw fixation and 254 (65%) tension band wiring. Nearly 100% of patients with displaced olecranon fractures are currently treated operatively at our hospitals. All patients were followed for at least four months. Two hundred three of the 392 (52%) patients were followed for one year or more. Ninety-nine patients (25%) had a second operation, 92 (93%) at least in part for implant removal (12 for wire migration [3% of all fractures, 12% of reoperations]). We considered patient-related, fracture-related, and implant-related endpoints as possible factors associated with reoperation. With a total sample size of 99 reoperations, an α of 0.05, and an effect size of 0.3, we had 87% power.

RESULTS

Reoperation was less common in men (36 [36%], women: 63 [64%]; adjusted odds ratio, 0.32; 95% confidence interval, 0.18-0.56; p < 0.001) and older patients (adjusted odds ratio, 0.75; 95% confidence interval, 0.65-0.87; p < 0.001). Similarly, request for implant removal was less in men (33 [36%], women: 59 [64%], adjusted odds ratio, 0.31; 95% confidence interval, 0.18-0.56; p < 0.001) and older patients (adjusted odds ratio, 0.75; 95% confidence interval, 0.65-0.87; p < 0.001).

CONCLUSIONS

Patients who have operative fixation of a fracture of the olecranon can be counseled that most patients keep their implants, that only 3% experience implant migration, and that technical factors such as the type or configuration of an implant seem less important than personal factors in determining who requests a second surgery for implant removal.

LEVEL OF EVIDENCE

Level III, prognostic study.

Are Allogeneic Blood Transfusions Associated With Decreased Survival After Surgery for Long-bone Metastatic Fractures?

BACKGROUND

Previous studies have shown that perioperative blood transfusion increases cancer recurrence and decreases patient survival after resection of primary malignancies. The question arises whether this association also exists in patients with already disseminated disease undergoing surgery for metastatic long-bone fractures.

PURPOSES

We sought to determine whether perioperative allogeneic blood transfusion is associated with decreased survival after operative treatment of long-bone metastatic fractures after accounting for clinical, laboratory, and treatment factors. Secondarily, we aimed to identify potential factors that are associated with decreased survival.

METHODS

We included 789 patients in our retrospective study who underwent surgery at two institutions for a pathologic or impending metastatic long-bone fracture. We used multivariable Cox proportional hazards regression model analysis to assess the relationship of perioperative allogeneic blood transfusion with survival, and accounted for patient age, sex, comorbidities, BMI, tumor type, fracture type and location, presence of other bone and visceral metastases, previous radiotherapy and systemic therapy, preoperative embolization, preoperative hemoglobin level, treatment type, anesthesia time, blood loss, duration of hospital admission, year of surgery, and hospital.

RESULTS

Considering transfusion as an "exposure," and comparing patients who received transfusions with those who did not, we found that blood transfusion was not associated with decreased survival after accounting for all explanatory variables (hazard ratio [HR] 1.06; 95% CI, 0.87-1.30; p = 0.57). Evaluating transfusion in terms of dose-response, we found that patients who received more transfusions had lower survival compared with those who had fewer transfusions after accounting for all explanatory variables (HR per unit of blood transfused, 1.07; 95% CI, 1.02-1.12; p = 0.005). We found that age (HR, 1.02; 95% CI, 1.01-1.02; p < 0.001), comorbidity status (HR, 1.06; 95% CI, 1.01-1.10; p = 0.014), duration of hospital stay (HR, 1.02; 95% CI 1.00-1.03; p = 0.021), tumor type (HR, 1.71; 95% CI, 1.44-2.03; p < 0.001), and visceral metastases (HR, 1.59; 95% CI, 1.34-1.88; p < 0.001) were independently associated with survival.

CONCLUSION

We found that exposure to perioperative allogeneic blood transfusion does not decrease survival, with the numbers available. However, our sample size might have been insufficient to reveal a small but potentially relevant effect. Our results do suggest a dose-response relationship; patients who received more transfusions had lower survival compared with those with fewer transfusions. Risk of death increased by 7% per unit of blood transfused.

LEVEL OF EVIDENCE

Level III, prognostic study.

Incidence of surgical site infection after spine surgery: what is the impact of the definition of infection?

BACKGROUND

Orthopaedic surgical site infections (SSIs) can delay recovery, add impairments, and decrease quality of life, particularly in patients undergoing spine surgery, in whom SSIs may also be more common. Efforts to prevent and treat SSIs of the spine rely on the identification and registration of these adverse events in large databases. The effective use of these databases to answer clinical questions depends on how the conditions in question, such as infection, are defined in the databases queried, but the degree to which different definitions of infection might cause different risk factors to be identified by those databases has not been evaluated.

QUESTIONS/PURPOSES

The purpose of this study was to determine whether different definitions of SSI identify different risk factors for SSI. Specifically, we compared the International Classification of Diseases, 9th Revision (ICD-9) coding, Centers for Disease Control and Prevention (CDC) criteria for deep infection, and incision and débridement for infection to determine if each is associated with distinct risk factors for SSI.

METHODS

In this single-center retrospective study, a sample of 5761 adult patients who had an orthopaedic spine surgery between January 2003 and August 2013 were identified from our institutional database. The mean age of the patients was 56 years (± 16 SD), and slightly more than half were men. We applied three different definitions of infection: ICD-9 code for SSI, the CDC criteria for deep infection, and incision and débridement for infection. Three hundred sixty-one (6%) of the 5761 surgeries received an ICD-9 code for SSI within 90 days of surgery. After review of the medical records of these 361 patients, 216 (4%) met the CDC criteria for deep SSI, and 189 (3%) were taken to the operating room for irrigation and débridement within 180 days of the day of surgery.

RESULTS

We found the Charlson Comorbidity Index, the duration of the operation, obesity, and posterior surgical approach were independently associated with a higher risk of infection for each of the three definitions of SSI. The influence of malnutrition, smoking, specific procedures, and specific surgeons varied by definition of infection. These elements accounted for approximately 6% of the variability in the risk of developing an infection.

CONCLUSIONS

The frequency of SSI after spine surgery varied according to the definition of an infection, but the most important risk factors did not. We conclude that large database studies may be better suited for identifying risk factors than for determining absolute numbers of infections.

LEVEL OF EVIDENCE

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

High-throughput screening of dipeptide utilization mediated by the ABC transporter DppBCDF and its substrate-binding proteins DppA1-A5 in Pseudomonas aeruginosa

In this study, we show that the dppBCDF operon of Pseudomonas aeruginosa PA14 encodes an ABC transporter responsible for the utilization of di/tripeptides. The substrate specificity of ABC transporters is determined by its associated substrate-binding proteins (SBPs). Whereas in E. coli only one protein, DppA, determines the specificity of the transporter, five orthologous SBPs, DppA1-A5 are present in P. aeruginosa. Multiple SBPs might broaden the substrate specificity by increasing the transporter capacity. We utilized the Biolog phenotype MicroArray technology to investigate utilization of di/tripeptides in mutants lacking either the transport machinery or all of the five SBPs. This high-throughput method enabled us to screen hundreds of dipeptides with various side-chains, and subsequently, to determine the substrate profile of the dipeptide permease. The substrate spectrum of the SBPs was elucidated by complementation of a penta mutant, deficient of all five SBPs, with plasmids carrying individual SBPs. It became apparent that some dipeptides were utilized with different affinity for each SBP. We found that DppA2 shows the highest flexibility on substrate recognition and that DppA2 and DppA4 have a higher tendency to utilize tripeptides. DppA5 was not able to complement the penta mutant under our screening conditions. Phaseolotoxin, a toxic tripeptide inhibiting the enzyme ornithine carbamoyltransferase, is also transported into P. aeruginosa via the DppBCDF permease. The SBP DppA1, and with much greater extend DppA3, are responsible for delivering the toxin to the permease. Our results provide a first overview of the substrate pattern of the ABC dipeptide transport machinery in P. aeruginosa.

Tetrahydrodipicolinate N-succinyltransferase and dihydrodipicolinate synthase from Pseudomonas aeruginosa: structure analysis and gene deletion

The diaminopimelic acid pathway of lysine biosynthesis has been suggested to provide attractive targets for the development of novel antibacterial drugs. Here we report the characterization of two enzymes from this pathway in the human pathogen Pseudomonas aeruginosa, utilizing structural biology, biochemistry and genetics. We show that tetrahydrodipicolinate N-succinyltransferase (DapD) from P. aeruginosa is specific for the L-stereoisomer of the amino substrate L-2-aminopimelate, and its D-enantiomer acts as a weak inhibitor. The crystal structures of this enzyme with L-2-aminopimelate and D-2-aminopimelate, respectively, reveal that both compounds bind at the same site of the enzyme. Comparison of the binding interactions of these ligands in the enzyme active site suggests misalignment of the amino group of D-2-aminopimelate for nucleophilic attack on the succinate moiety of the co-substrate succinyl-CoA as the structural basis of specificity and inhibition. P. aeruginosa mutants where the dapA gene had been deleted were viable and able to grow in a mouse lung infection model, suggesting that DapA is not an optimal target for drug development against this organism. Structure-based sequence alignments, based on the DapA crystal structure determined to 1.6 Å resolution revealed the presence of two homologues, PA0223 and PA4188, in P. aeruginosa that could substitute for DapA in the P. aeruginosa PAO1ΔdapA mutant. In vitro experiments using recombinant PA0223 protein could however not detect any DapA activity.

Quality of life in patients with various liver diseases: patients with HCV show greater mental impairment, while patients with PBC have greater physical impairment

Little is known comparing and contrasting quality of life (QoL) in patients with hepatitis C, compared to patients with other liver diseases. We performed two independent prospective cross-sectional studies including 511 and 284 patients with different forms of liver diseases. SF-36 was used in both studies. Fatigue Impact Score, WHO-BREF and Hospital Anxiety and Depression Scale (HADS) were used in either study only. In both studies, HCV-positive patients scored worse in the mental aspects of health-related QoL compared to other liver diseases, except for HBV in one study. Surprisingly, in both studies, quality of life was also significantly impaired in patients with viral clearance after interferon therapy but not after spontaneous clearance. Furthermore, patients with primary biliary cirrhosis showed significantly better mental health but significantly worse physical well-being. Liver diseases differ in their form of impaired QoL. In HCV, this impairment might not always return to normal after treatment-induced viral clearance. This may suggest that HCV either may not be involved in QoL impairment or may induce a process which persists after viral clearance in some patients.

Association of telomerase activity with radio- and chemosensitivity of neuroblastomas

BACKGROUND

Telomerase activity compensates shortening of telomeres during cell division and enables cancer cells to escape senescent processes. It is also supposed, that telomerase is associated with radio- and chemoresistance. In the here described study we systematically investigated the influence of telomerase activity (TA) and telomere length on the outcome of radio- and chemotherapy in neuroblastoma.

METHODS

We studied the effects on dominant negative (DN) mutant, wild type (WT) of the telomerase catalytic unit (hTERT) using neuroblastoma cell lines. The cells were irradiated with 60Co and treated with doxorubicin, etoposide, cisplatin and ifosfamide, respectively. Viability was determined by MTS/MTT-test and the GI50 was calculated. Telomere length was measured by southernblot analysis and TA by Trap-Assay.

RESULTS

Compared to the hTERT expressing cells the dominant negative cells showed increased radiosensitivity with decreased telomere length. Independent of telomere length, telomerase negative cells are significantly more sensitive to irradiation. The effect of TA knock-down or overexpression on chemosensitivity were dependent on TA, the anticancer drug, and the chemosensitivity of the maternal cell line.

CONCLUSIONS

Our results supported the concept of telomerase inhibition as an antiproliferative treatment approach in neuroblastomas. Telomerase inhibition increases the outcome of radiotherapy while in combination with chemotherapy the outcome depends on drug- and cell line and can be additive/synergistic or antagonistic. High telomerase activity is one distinct cancer stem cell feature and the here described cellular constructs in combination with stem cell markers like CD133, Aldehyddehydrogenase-1 (ALDH-1) or Side population (SP) may help to investigate the impact of telomerase activity on cancer stem cell survival under therapy.

Social impacts of large dam projects: a comparison of international case studies and implications for best practice

This paper applies the tool of social impact assessment (SIA) to understand the effects of large dam projects on human communities. We draw upon data from two recent SIA projects: the Lesotho Highlands Water Project in Southern Africa, and the Manwan Dam, located on the upper Mekong River in southwestern China. These two cases allow us to examine the social impacts of large dam projects through time and across various geographical scales. We focus on a range of social impacts common to many large-scale dam projects, including: the migration and resettlement of people near the dam sites; changes in the rural economy and employment structure; effects on infrastructure and housing; impacts on non-material or cultural aspects of life; and impacts on community health and gender relations. By identifying potential impacts in advance of a large dam project, agencies and policymakers can make better decisions about which interventions should be undertaken, and how. We conclude our analysis with an overview of lessons learned from the case studies and suggestions for best practice in assessing the social impacts of large dams. Conducting proper social impact assessments can help to promote development strategies that address the most important concerns for local populations, enhancing the long-term sustainability of dam projects.

Stable interference of EWS-FLI1 in an Ewing sarcoma cell line impairs IGF-1/IGF-1R signalling and reveals TOPK as a new target

BACKGROUND

Ewing sarcoma is a paradigm of solid tumour -bearing chromosomal translocations resulting in fusion proteins that act as deregulated transcription factors. Ewing sarcoma translocations fuse the EWS gene with an ETS transcription factor, mainly FLI1. Most of the EWS-FLI1 target genes still remain unknown and many have been identified in heterologous model systems.

METHODS

We have developed a stable RNA interference model knocking down EWS-FLI1 in the Ewing sarcoma cell line TC71. Gene expression analyses were performed to study the effect of RNA interference on the genetic signature of EWS-FLI1 and to identify genes that could contribute to tumourigenesis.

RESULTS

EWS-FLI1 inhibition induced apoptosis, reduced cell migratory and tumourigenic capacities, and caused reduction in tumour growth. IGF-1 was downregulated and the IGF-1/IGF-1R signalling pathway was impaired. PBK/TOPK (T-LAK cell-originated protein kinase) expression was decreased because of EWS-FLI1 inhibition. We showed that TOPK is a new target gene of EWS-FLI1. TOPK inhibition prompted a decrease in the proliferation rate and a dramatic change in the cell's ability to grow in coalescence.

CONCLUSION

This is the first report of TOPK activity in Ewing sarcoma and suggests a significant role of this MAPKK-like protein kinase in the Ewing sarcoma biology.

Component and protein domain exchange analysis of a thermoresponsive, two-component regulatory system of Pseudomonas syringae

Two closely related phytopathogenic bacterial strains, Pseudomonas syringae pv. glycinea PG4180 and P. syringae pv. tomato DC3000, produce the chlorosis-inducing phytotoxin coronatine (COR) in a remarkably divergent manner. PG4180 produces COR at the virulence-promoting temperature of 18 degrees C, but not at 28 degrees C. In contrast, temperature has no effect on COR synthesis in DC3000. A modified two-component system consisting of the histidine protein kinase (HPK), CorS, the response regulator (RR), CorR, and a third component, CorP, governs COR biosynthesis in both strains. A plasmid-based component and domain swapping approach was used to introduce different combinations of RRs, HPKs and hybrid HPKs into corS mutants of both strains. Subsequently, expression levels of the COR biosynthetic cma operon were determined using RNA dot-blot analysis, suggesting that CorRSP of PG4180 mediates a thermoresponsive phenotype dependent on the genomic background of each strain. The reciprocal experiment demonstrated a loss of temperature dependence in the corS mutant of PG4180. The presence of corR from PG4180 led to more pronounced cma expression in DC3000 and was associated with thermoresponsiveness, while corS of PG4180 did not mediate a temperature-dependent phenotype in the DC3000 mutant containing native corR and corP. These findings were substantiated by RT-PCR experiments. The C-terminal domain of CorS of PG4180 mediated thermosensing, while the N terminus did not respond to temperature changes, suggesting cytosolic perception of the temperature signal.

Expression analysis of pancreatic cancer cell lines reveals association of enhanced gene transcription and genomic amplifications at the 8q22.1 and 8q24.22 loci

Despite tremendous effort and progress in the diagnostics of pancreatic cancer with respect to imaging techniques and molecular genetics, only very few patients can be cured by surgery leading to a 5-year survival rate of only 3%. Especially the lack of chemotherapeutical options in this entity requires a better understanding of the molecular mechanisms leading to pancreatic carcinoma growth and progression in order to develop novel treatment regimens. To identify signaling pathways that are critical for this tumor entity, we compared six well-established pancreatic cancer cell lines (Capan-1, Capan-2, HUP-T3, HUP-T4, KCL-MOH, PaTu-8903) with colon cancer cell lines and tumor cell lines of non-epithelial origin by expression profiling. For this purpose we employed Human Genome Focus Arrays representing about 8500 well annotated human genes. We identified 353 genes with significantly high expression in the group of pancreatic carcinomas. Based on Gene Ontology annotations these genes are especially involved in Rho protein signal transduction, proteasome activator activity, cell motility, apoptotic program, and cell-cell adhesion processes indicating these pathways to be interesting candidates for the design of targeted therapies. Most pancreatic carcinomas are characterized by mutations in the TP53 and the KRAS genes and the absence of microsatellite instability, which could also be confirmed for our panel of pancreatic carcinoma cell lines. Looking for individual differences within this group that may be responsible for more or less aggressive behavior, we identified genomic amplifications at the 8q22.1 and the 8q24.22 loci to be associated with enhanced gene transcription. Because we have previously shown that gains of genomic material from the long arm of chromosome 8 have an adverse effect on the outcome of pancreatic carcinoma patients, we conclude that functional analysis of amplified genes at 8q22 and/or 8q24 may lead to an improved understanding of pancreatic carcinoma progression.

A Temperature‐Sensing Histidine Kinase—Function, Genetics, and Membrane Topology

Two-component systems provide a means for bacteria to sense and adapt to environmental signals in order to survive in a continuously changing environment. Understanding of the mechanism by which these systems function is important in combating bacterial infections because many bacterial two-component systems are associated with virulence. The plant pathogenic bacterium Pseudomonas syringae pv. glycinea PG4180 synthesizes high levels of the phytotoxin coronatine at the virulence-promoting temperature of 18 degrees , but not at 28 degrees , the optimal growth temperature. Temperature-dependent coronatine biosynthesis is regulated by a modified two-component system, consisting of the response regulator, CorR, the histidine protein kinase CorS, and a third component, CorP. To elucidate the mechanism by which CorRSP functions, genetic, transcriptional, and biochemical analyses were applied, including in vitro and in planta reporter gene analysis, mRNA quantification, protein expression, mutagenesis, and membrane topology analysis. A combination of these techniques helped to elucidate, to a considerable extent, the temperature-sensing activity of CorS, which seems to act as a membrane-bound molecular thermometer.

Constitutive activation of neuregulin/ERBB3 signaling pathway in clear cell sarcoma of soft tissue

Clear cell sarcoma of soft tissue (CCSST) represents a highly malignant tumor of the musculoskeletal system that is characterized by the chromosomal translocation t(12;22)(q13;q12) of the Ewing sarcoma gene (EWSR1) and activating transcription factor 1 (ATF1). In a former microarray expression study, we identified ERBB3, a member of the epidermal growth factor receptor (EGFR) family, as a promising new diagnostic marker in the differential diagnosis of CCSST. Here we show that, besides ErbB3, all CCSST cell lines (n = 8) also express the ErbB2 receptor or the ErbB4 receptor, representing an adequate coreceptor of ErbB3. The phosphorylation status of ErbB3 revealed these receptor pairs to be either constitutively activated in CCSST cells with high neuregulin-1 (NRG1) expression (n = 4) or activatable by exogenic NRG1 in cells showing low amounts of NRG1 mRNA (n = 4). Exogenous NRG1 stimulated the growth of a subset of CCSST cells but did not affect the kinetics of another subset. This difference was not strictly dependent on endogenous NRG1 expression; however, the growth-inhibiting effect of the pan-ErbB tyrosine kinase inhibitor CI-1033 or PD158780 clearly correlated with NRG1 expression indicating an autocrine growth stimulation loop which may constitute an interesting target of new therapeutic strategies in this tumor entity.

Doxorubicin modulates telomerase activity in Ewing's sarcoma in vitro and in vivo

Since most tumours escape replicative senescence by re-activation of the enzyme telomerase, telomerase is a promising target in the treatment of cancer and a promising marker for diagnosis and therapeutic response. We evaluated the effects of doxorubicin, one of the most active drugs in the treatment of Ewing's sarcoma, on telomerase in the human Ewing's sarcoma cell line STA-ET-1 in vitro and in STA-ET-1 xenografts in vivo. Telomerase activity (TA) was examined by TRAP-assay and real-time PCR. Real-time PCR was also used to quantify the mRNA expression of the catalytic subunit of telomerase (hTERT). In vitro growth inhibition was determined by the MTT-assay. Tumour xenografts were analyzed for tumour volume, apoptosis, necrosis, and proliferation. Doxorubicin concentrations that inhibited in vitro growth of STA-ET-1 by 50% compared to untreated controls ranged between 0.14 microM after 24 h and 0.01 microM after 72 h. Compared to untreated controls doxorubicin reduced TA in STA-ET-1 at toxic concentrations, but increased TA at non-toxic concentrations. In comparison with untreated xenografts, TA was reduced to 65% and hTERT expression dropped to 25% within 72 h in xenografts treated with 17.5 mg/kg doxorubicin i.p.; both recovered to initial values after 264 h. The rate of proliferating cells dropped to 70% within 96 h and increased thereafter. The highest rates of necrosis and apoptosis were seen after 96 h. hTERT expression co-varied significantly with proliferation but not with TA, apoptosis, and necrosis. No correlation was observed between TA, proliferation, apoptosis and necrosis. The results suggest doxorubicin induces down-regulation of hTERT gene expression that at least in part modulates TA in these tumours.

Biochip analysis: status quo

Biochips are collections of miniaturized test sites (microarrays) arranged on a solid substrate onto which a large number of biomolecules are attached with high density. Like a computer chip performing millions of mathematical operations in a few split seconds, a biochip allows for simultaneous analyses of thousands of biological reactions, such as decoding genes, in a few seconds. Biochip technologies can be applied to numerous fields including genomic, proteomic, and glycomic research, as well as pharmacology and toxicology. However, one of the most common applications is in the determination of gene expression in human cells and tissues. Global gene expression analysis has helped to identify important genes and signalling pathways in human malignant tumors. And there is hope that microarrays will make the step from "the (laboratory) bench to the bedside (of the patient)". Recent studies have indeed revealed that analysis of differential gene expression by microarrays may help to identify subtypes of malignant tumors, that allow a risk stratification of the patients. However, there are several issues that need to be addressed before microarrays may become a tool for routine diagnostics, such as problems with bioinformatic analysis, construction of disease or tissue specific microarrays with only limited numbers of genes of interest, standard operation procedures for tissue preparation to prevent RNA degradation, etc.. In this article, an overview over of the multifarious biochip applications and technologies, its limitations, challenges and future developments is provided.

Profiling and functional annotation of mRNA gene expression in pediatric rhabdomyosarcoma and Ewing's sarcoma

Using Affymetrix oligonucleotide microarrays, we analyzed mRNA gene expression patterns of 12 primary pediatric rhabdomyosarcomas (RMS) and 11 Ewing's sarcomas (EWS), which belong to the small round blue cell tumors (SRBCTs). Diagnostic classification of these cancers is frequently complicated by the highly similar appearance in routine histology, and additional molecular markers could significantly improve tumor classification. A combination of three independent statistical approaches (t-test, SAM, k-nearest neighborhood analysis) resulted in 101 highly significant probe sets that clearly discriminate between EWS and RMS. We identified novel marker transcripts that have not been previously associated with either RMS or EWS yet, including CITED2, glypican 3 (GPC3), and cyclin D1 (CCND1). Expression levels for selected candidate genes were validated by quantitative real-time reverse-transcription PCR. Furthermore, to identify biologically meaningful trends, functional annotations were assigned to 946 genes differentially expressed between EWS and RMS (t-test). Genes involved in protein biosynthesis (n = 28) and complex assembly (n = 9), lipid metabolism (n = 23), energy generation (n = 22), and mRNA processing (n = 11) were expressed significantly higher in EWS. Thus, functional annotation of tumor-specific genes reveals detailed insights into tumor biology and differentiation-specific expression patterns and gives important clues related to the possible cellular origin of these pediatric tumors. Supplementary material for this article is available at the International Journal of Cancer website at http://www.interscience.wiley.com/jpages/0020-7136/suppmat/index.html.

Expression Profiling of t(12;22) Positive Clear Cell Sarcoma of Soft Tissue Cell Lines Reveals Characteristic Up-Regulation of Potential New Marker Genes Including ERBB3

Clear cell sarcoma of soft tissue (CCSST), also known as malignant melanoma of soft parts, represents a rare lesion of the musculoskeletal system usually affecting adolescents and young adults. CCSST is typified by a chromosomal t(12;22)(q13;q12) translocation resulting in a fusion between the Ewing sarcoma gene (EWSR1) and activating transcription factor 1 (ATF1), of which the activity in nontransformed cells is regulated by cyclic AMP. Our aim was to identify critical differentially expressed genes in CCSST tumor cells in comparison with other solid tumors affecting children and young adults to better understand signaling pathways regulating specific features of the development and progression of this tumor entity. We applied Affymetrix Human Genome U95Av2 oligonucleotide microarrays representing approximately 12,000 genes to generate the expression profiles of the CCSST cell lines GG-62, DTC-1, KAO, MST2, MST3, and Su-CC-S1 in comparison with 8 neuroblastoma, 7 Ewing tumor, and 6 osteosarcoma cell lines. Subsequent hierarchical clustering of microarray data clearly separated all four of the tumor types from each other and identified differentially expressed transcripts, which are characteristically up-regulated in CCSST. Statistical analysis revealed a group of 331 probe sets, representing approximately 300 significant (P < 0.001) differentially regulated genes, which clearly discriminated between the CCSST and other tumor samples. Besides genes that were already known to be highly expressed in CCSST, like S100A11 (S100 protein) or MITF (microphthalmia-associated transcription factor), this group shows an obvious portion of genes that are involved in cyclic AMP response or regulation, in pigmentation processes, or in neuronal structure and signaling. Comparison with other expression profile analyses on neuroectodermal childhood tumors confirms the high robustness of this strategy to characterize tumor entities based on their gene expression. We found the avian erythroblastic leukemia viral oncogene homologue 3 (ERBB3) to be one of the most dramatically up-regulated genes in CCSST. Quantitative real-time PCR and Northern blot analysis verified the mRNA abundance and confirmed the absence of the inhibitory transcript variant of this gene. The protein product of the member of the epidermal growth factor receptor family ERBB3 could be shown to be highly present in all of the CCSST cell lines investigated, as well as in 18 of 20 primary tumor biopsies. In conclusion, our data demonstrate new aspects of the phenotype and the biological behavior of CCSST and reveal ERBB3 to be a useful diagnostic marker.

Radiation-induced changes of telomerase activity in a human Ewing xenograft tumor

AIM

The effect of ionizing irradiation on telomerase activity and further associated biological factors was evaluated in a human Ewing tumor xenograft model on nude mice.

MATERIAL AND METHODS

The human Ewing tumor cell line STA-ET-1 was established in a nude mouse model. Initially, the dose-response relationship for the tumor model was established. For the radiation experiments two dose levels were chosen: 5 Gy and 30 Gy. After 5 Gy, there was no significant growth delay whereas after 30 Gy there was a marked growth delay without the induction of a complete remission. Tumors were examined 6, 12, 24, 48, 72, and 96 hours post irradiation. After irradiation with 30 Gy further time points were 6, 9, 12 and 15 days. For each dose and time group, three tumors were evaluated.

RESULTS

There was a reduction of telomerase activity after 5 Gy to 50% (not statistically significant) after 3 days; however, after 30 Gy there was a reduction of telomerase activity to 23% of the initial value after 6 days (p = 0.001). Telomerase activity correlated with the expression of human telomerase reverse transcriptase (hTERT), but not with the expression of telomerase-associated protein (TP1) and human telomerase RNA (hTR). The maximal amounts of necrosis or apoptosis after 30 Gy were 19% and 6.9%, respectively.

CONCLUSIONS

Ionizing radiation reduces telomerase activity and the expression of hTERT which cannot be explained by the induction of necrosis or apoptosis alone. The reduction of telomerase activity may contribute to delayed cell death after radiotherapy. The combined use of radiation and specific telomerase inhibitors may be a potentially synergistic treatment strategy.

Telomerase as a prognostic marker in breast cancer: high-throughput tissue microarray analysis of hTERT and hTR

Telomerase activity (TA) has been shown to correlate with poor clinical outcome in various tumour entities, indicating that tumours expressing this enzyme may be more aggressive and that TA may be a useful prognostic marker. For breast cancer, however, TA is a controversial prognostic marker; whereas some studies suggest an association between TA and disease outcome, others do not find this association. This study used tissue microarrays (breast carcinoma prognosis arrays) containing 611 samples (each 0.6 mm in diameter) from the tumour centre of paraffin-embedded breast carcinomas to analyse the catalytic subunit of telomerase, human telomerase reverse-transcriptase (hTERT), and the internal RNA component (hTR), which are the core components of the telomerase holoenzyme complex. hTERT protein expression was obtained by immunohistochemistry (human anti-telomerase antibody Ab-2, Calbiochem), and hTR RNA was measured by radioactive in situ hybridization. hTERT and hTR expression were determined semi-quantitatively and graded (scores 1-4). Clinical data, such as histological subtype, pT stage, tumour diameter, pN stage, BRE grade, tumour-specific survival (in months), patient's age and others, were available for statistical analysis. A statistically significant correlation was found between tumour-specific survival (overall survival) and hTERT expression (p < 0.0001) or hTR expression (p = 0.00110). Tumours with higher scores (scores 3, 4) for hTR and/or hTERT were associated with a worse prognosis. In multivariate analysis, hTERT expression was an independent prognostic factor. Previous studies, focusing on analysis of TA in smaller numbers of fresh-frozen breast carcinomas by the TRAP assay, gave controversial results with respect to TA as a prognostic marker. Using tissue microarrays from 611 breast carcinomas, this study has demonstrated that increased expression levels of the telomerase core components, hTERT and hTR, are associated with lower overall survival. These findings suggest that TA should be included in future validation studies as a prognostic marker in breast cancer.

The use of antisense mRNA to inhibit the tonoplast H+ ATPase in carrot

Carrot root cells were transformed with the coding or 5' noncoding regions of the carrot vacuolar H+ ATPase A subunit cDNA cloned in the antisense orientation behind the cauliflower mosaic virus 35S promoter. Bafilomycin-sensitive ATPase, H(+)-pumping, and 14C-O-methyl-glucose uptake activities were specifically inhibited in the tonoplast fractions of mutant cell lines. Protein gel blotting confirmed that the expression of the A subunit was inhibited in the tonoplast fraction, but not in the Golgi fraction. Two-dimensional protein gel blots of total microsomes of wild-type and control transformant cell lines revealed two major immunoreactive polypeptides in the acidic pI range. In contrast, highly purified tonoplast membranes contained only the less acidic polypeptide. Because the less acidic polypeptide was preferentially diminished in the two antisense cell lines, we infer that the antisense constructs specifically blocked expression of a tonoplast-specific isoform of the V-ATPase A subunit in carrot. Regenerated plants containing the antisense constructs exhibited altered leaf morphologies and reduced cell expansion. The altered phenotype was correlated with the presence of the antisense construct.