Towards optimal use of antithrombotic therapy of people with cancer at the end of life: A research protocol for the development and implementation of the SERENITY shared decision support tool

BACKGROUND

Even though antithrombotic therapy has probably little or even negative effects on the well-being of people with cancer during their last year of life, deprescribing antithrombotic therapy at the end of life is rare in practice. It is often continued until death, possibly resulting in excess bleeding, an increased disease burden and higher healthcare costs.

METHODS

The SERENITY consortium comprises researchers and clinicians from eight European countries with specialties in different clinical fields, epidemiology and psychology. SERENITY will use a comprehensive approach combining a realist review, flash mob research, epidemiological studies, and qualitative interviews. The results of these studies will be used in a Delphi process to reach a consensus on the optimal design of the shared decision support tool. Next, the shared decision support tool will be tested in a randomised controlled trial. A targeted implementation and dissemination plan will be developed to enable the use of the SERENITY tool across Europe, as well as its incorporation in clinical guidelines and policies. The entire project is funded by Horizon Europe.

RESULTS

SERENITY will develop an information-driven shared decision support tool that will facilitate treatment decisions regarding the appropriate use of antithrombotic therapy in people with cancer at the end of life.

CONCLUSIONS

We aim to develop an intervention that guides the appropriate use of antithrombotic therapy, prevents bleeding complications, and saves healthcare costs. Hopefully, usage of the tool leads to enhanced empowerment and improved quality of life and treatment satisfaction of people with advanced cancer and their care givers.

Characterization of SARS-CoV-2 humoral immune response in a subject with unique sampling: A case report

BACKGROUND

The development of vaccine candidates for COVID-19, and the administration of booster vaccines, has meant a significant reduction in COVID-19 related deaths world-wide and the easing of global restrictions. However, new variants of SARS-CoV-2 have emerged with less susceptibility to vaccine induced immunity leading to breakthrough infections among vaccinated people. It is generally acknowledged that immunoglobulins play the major role in immune-protection, primarily through binding to the SARS-COV-2 receptor binding domain (RBD) and thereby inhibiting viral binding to the ACE2 receptor. However, there are limited investigations of anti-RBD isotypes (IgM, IgG, IgA) and IgG subclasses (IgG1-4) over the course of vaccination and breakthrough infection.

METHOD

In this study, SARS-CoV-2 humoral immunity is examined in a single subject with unique longitudinal sampling. Over a two year period, the subject received three doses of vaccine, had two active breakthrough infections and 22 blood samples collected. Serological testing included anti-nucleocapsid total antibodies, anti-RBD total antibodies, IgG, IgA, IgM and IgG subclasses, neutralization and ACE2 inhibition against the wildtype (WT), Delta and Omicron variants.

RESULTS

Vaccination and breakthrough infections induced IgG, specifically IgG1 and IgG4 as well as IgM and IgA. IgG1 and IgG4 responses were cross reactive and associated with broad inhibition.

CONCLUSION

The findings here provide novel insights into humoral immune response characteristics associated with SARS-CoV-2 breakthrough infections.

SARS-CoV-2 Neutralizing Antibody Responses towards Full-Length Spike Protein and the Receptor-Binding Domain

Tools to monitor SARS-CoV-2 transmission and immune responses are needed. We present a neutralization ELISA to determine the levels of Ab-mediated virus neutralization and a preclinical model of focused immunization strategy. The ELISA is strongly correlated with the elaborate plaque reduction neutralization test (ρ = 0.9231, p < 0.0001). The neutralization potency of convalescent sera strongly correlates to IgG titers against SARS-CoV-2 receptor-binding domain (RBD) and spike (ρ = 0.8291 and 0.8297, respectively; p < 0.0001) and to a lesser extent with the IgG titers against protein N (ρ = 0.6471, p < 0.0001). The preclinical vaccine NMRI mice models using RBD and full-length spike Ag as immunogens show a profound Ab neutralization capacity (IC₅₀ = 1.9 × 10⁴ to 2.6 × 10⁴ and 3.9 × 10³ to 5.2 × 10³, respectively). Using a panel of novel high-affinity murine mAbs, we also show that a majority of the RBD-raised mAbs have inhibitory properties, whereas only a few of the spike-raised mAbs do. The ELISA-based viral neutralization test offers a time- and cost-effective alternative to the plaque reduction neutralization test. The immunization results indicate that vaccine strategies focused only on the RBD region may have advantages compared with the full spike.

Site-Specific O-Glycosylation Analysis of SARS-CoV-2 Spike Protein Produced in Insect and Human Cells

Enveloped viruses hijack not only the host translation processes, but also its glycosylation machinery, and to a variable extent cover viral surface proteins with tolerogenic host-like structures. SARS-CoV-2 surface protein S presents as a trimer on the viral surface and is covered by a dense shield of N-linked glycans, and a few O-glycosites have been reported. The location of O-glycans is controlled by a large family of initiating enzymes with variable expression in cells and tissues and hence is difficult to predict. Here, we used our well-established O-glycoproteomic workflows to map the precise positions of O-linked glycosylation sites on three different entities of protein S—insect cell or human cell-produced ectodomains, or insect cell derived receptor binding domain (RBD). In total 25 O-glycosites were identified, with similar patterns in the two ectodomains of different cell origin, and a distinct pattern of the monomeric RBD. Strikingly, 16 out of 25 O-glycosites were located within three amino acids from known N-glycosites. However, O-glycosylation was primarily found on peptides that were unoccupied by N-glycans, and otherwise had low overall occupancy. This suggests possible complementary functions of O-glycans in immune shielding and negligible effects of O-glycosylation on subunit vaccine design for SARS-CoV-2.

Capsid-like particles decorated with the SARS-CoV-2 receptor-binding domain elicit strong virus neutralization activity

The rapid development of a SARS-CoV-2 vaccine is a global priority. Here, we develop two capsid-like particle (CLP)-based vaccines displaying the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. RBD antigens are displayed on AP205 CLPs through a split-protein Tag/Catcher, ensuring unidirectional and high-density display of RBD. Both soluble recombinant RBD and RBD displayed on CLPs bind the ACE2 receptor with nanomolar affinity. Mice are vaccinated with soluble RBD or CLP-displayed RBD, formulated in Squalene-Water-Emulsion. The RBD-CLP vaccines induce higher levels of serum anti-spike antibodies than the soluble RBD vaccines. Remarkably, one injection with our lead RBD-CLP vaccine in mice elicits virus neutralization antibody titers comparable to those found in patients that had recovered from COVID-19. Following booster vaccinations, the virus neutralization titers exceed those measured after natural infection, at serum dilutions above 1:10,000. Thus, the RBD-CLP vaccine is a highly promising candidate for preventing COVID-19.

Capture and Detection of Circulating Glioma Cells Using the Recombinant VAR2CSA Malaria Protein

Diffuse gliomas are the most common primary malignant brain tumor. Although extracranial metastases are rarely observed, recent studies have shown the presence of circulating tumor cells (CTCs) in the blood of glioma patients, confirming that a subset of tumor cells are capable of entering the circulation. The isolation and characterization of CTCs could provide a non-invasive method for repeated analysis of the mutational and phenotypic state of the tumor during the course of disease. However, the efficient detection of glioma CTCs has proven to be challenging due to the lack of consistently expressed tumor markers and high inter- and intra-tumor heterogeneity. Thus, for this field to progress, an omnipresent but specific marker of glioma CTCs is required. In this article, we demonstrate how the recombinant malaria VAR2CSA protein (rVAR2) can be used for the capture and detection of glioma cell lines that are spiked into blood through binding to a cancer-specific oncofetal chondroitin sulfate (ofCS). When using rVAR2 pull-down from glioma cells, we identified a panel of proteoglycans, known to be essential for glioma progression. Finally, the clinical feasibility of this work is supported by the rVAR2-based isolation and detection of CTCs from glioma patient blood samples, which highlights ofCS as a potential clinical target for CTC isolation.

High incidence of candidaemia in a nationwide cohort: Underlying diseases, risk factors and mortality

BACKGROUND

Denmark has a high incidence rate of candidaemia. A Nordic study suggested a higher Danish prevalence of haematological malignancies as an underlying reason. This nationwide study ascertained clinical characteristics of Danish candidaemia patients and investigated potential factors contributing to the high incidence and mortality.

METHODS

Microbiological and clinical data for candidaemia patients in 2010-2011 were retrieved. 30-day mortality was estimated by hazard ratios (HR) with 95% confidence intervals (CI, Cox regression).

RESULTS

Data were available for 912/973 candidaemia episodes (93.7%). Intensive care unit (ICU) held the largest share of patients (43.2%). Prevalent host factors were multi-morbidity (≥2 underlying diseases, 74.2%) and gastrointestinal disease (52.5%). Haematological disease was infrequent (7.8%). Risk factors included antibiotic exposure (90.5%), CVC (71.9%) and Candida colonisation (66.7%). 30-day mortality was 43.4%, and 53.6% in ICU. Mortality was lower for patients with recent abdominal surgery (HR 0.70, 95% CI: 0.54-0.92).

CONCLUSION

A substantial prevalence of multi-morbidity and a high 30-day mortality was found. We hypothesise, that an increasing population of severely ill patients with prolonged supportive treatment and microbiological testing may in part explain the high candidaemia incidence in Denmark. Nationwide studies are warranted to clarify this issue.

Long-term mental wellbeing of adolescents and young adults diagnosed with venous thromboembolism: results from a multistage mixed methods study

Essentials Long-term mental wellbeing of adolescents and young adults with venous thromboembolism is unclear. This multistage mixed methods study was based on Danish nationwide registry data and interviews. Mental wellbeing is negatively impacted in the long-term and uncertainty of recurrence is pivotal. The perceived health threat is more important than disease severity for long-term mental wellbeing.

SUMMARY

Background Critical and chronic illness in youth can lead to impaired mental wellbeing. Venous thromboembolism (VTE) is a potentially traumatic and life-threatening condition. Nonetheless, the long-term mental wellbeing of adolescents and young adults (AYAS) with VTE is unclear. Objectives To investigate the long-term mental wellbeing of AYAS (aged 13-33 years) diagnosed with VTE. Methods We performed a multistage mixed method study based on data from the Danish nationwide health registries, and semistructured interviews with 12 AYAS diagnosed with VTE. An integrated mixed methods interpretation of the findings was conducted through narrative weaving and joint displays. Results The integrated mixed methods interpretation showed that the mental wellbeing of AYAS with VTE had a chronic perspective, with a persistently higher risk of psychotropic drug purchase among AYAS with a first-time diagnosis of VTE than among sex-matched and age-matched population controls and AYAS with a first-time diagnosis of insulin-dependent diabetes mellitus. Impaired mental wellbeing was largely connected to a fear of recurrence and concomitant uncertainty. Therefore, it was important for the long-term mental wellbeing to navigate uncertainty. The perceived health threat played a more profound role in long-term mental wellbeing than disease severity, as the potential life threat was the pivot which pointed back to the initial VTE and forward to the perception of future health threat and the potential risk of dying of a recurrent event. Conclusion Our findings show that the long-term mental wellbeing of AYAS diagnosed with VTE is negatively affected, and highlights these patients' need for adequate support.

Risk factors for extended-spectrum β-lactamase-producing Escherichia coli urinary tract infection in the community in Denmark: a case-control study

OBJECTIVE

To verify the role of proton pump inhibitors (PPI) and nitrofurantoin, which have appeared as novel risk factors for carriage of extended-spectrum β-lactamase (ESBL) -producing Escherichia coli, as risk factors for ESBL E. coli urinary tract infection (UTI). We included known risk factors to ascertain whether our findings are comparable with those of previous studies.

METHODS

Population-based case-control study including 339 cases with community-onset ESBL E. coli UTI in 2007-2012, 3390 non-ESBL E. coli UTI controls and 3390 population controls. We investigated potential risk factors by estimating ORs and 95% CIs adjusting for sex, age and co-morbidity.

RESULTS

Comparing cases with non-ESBL E. coli UTI, PPI use yielded an OR of 1.6 (95% CI 1.2-2.0) and antibiotic exposure gave an OR of 1.4 (95% CI 1.1-1.8); these were driven by nitrofurantoin (OR 1.8; 95% CI 1.3-2.6) and macrolides (OR 1.7; 95% CI 1.2-2.3). Other risk factors included previous hospitalization with one or two and more than two hospitalizations versus none yielding ORs of 1.9 (95% CI 1.4-2.5) and 4.6 (95% CI 3.2-6.8), recent surgery (OR 2.0; 95% CI 1.5-2.8), renal disease (OR 2.2; 95% CI 1.4-3.4), chronic pulmonary disease (OR 1.4; 95% CI 1.0-2.0) and cancer (OR 1.5; 95% CI 1.1-2.1). Comparing cases with population controls, we found that most risk factors were also risk factors for non-ESBL UTI.

CONCLUSIONS

ESBL E. coli UTI were associated with previous hospitalization and surgery. Nitrofurantoin and macrolides augmented the risk. PPIs had a moderate effect but may be important facilitators of ESBL carriage due to their widespread use.

Effectiveness of intensification therapies in Danes with Type 2 diabetes who use basal insulin: a population-based study

AIMS

To examine the usage and real-life effectiveness of intensification therapies in people with Type 2 diabetes treated with basal insulin.

METHODS

We used population-based healthcare databases in Denmark during 2000-2012 to identify all individuals with a first basal insulin prescription (with or without oral drugs), and evaluated subsequent intensification therapy with bolus insulin, premixed insulin or glucagon-like peptide-1 (GLP-1) receptor agonists. Poisson regression was used to compute the adjusted relative risks of reaching glycaemic control targets.

RESULTS

We included 7034 initiators of basal insulin (median age 64 years, diabetes duration 5.3 years, 84% with oral co-medication and median (interquartile range) pre-insulin HbA_1c level 77 (65-92) mmol/mol [9.2% (8.1-10.6%)]. Of these, 3076 (43.7%) received intensification therapy after a median of 11 months: 58.5% with premixed insulin, 29.0% with bolus insulin, 10.6% with GLP-1 receptor agonists, and 1.9% with more than one add-on. Overall, 22% had attained an HbA_1c level of < 53 mmol/mol (< 7%) by 3-6 months after intensification, while 38% attained an HbA_1c < 58 mmol/mol (< 7.5%). Compared with premixed insulin intensification, attainment of HbA_1c < 53 and < 58 mmol/mol was similar with bolus insulin add-on [adjusted relative risk 1.03 (95% CI 0.86-1.24) and 1.02 (95% CI 0.91-1.15), and higher for GLP-1 receptor agonist add-on [adjusted relative risk 1.56 (95% CI 1.27-1.92) and 1.27 (1.10-1.47)].

CONCLUSIONS

Among people with Type 2 diabetes, 22 and 38% reached a target HbA_1c < 53 mmol/mol (< 7%) or < 58 mmol/mol (< 7.5%), respectively, after intensification of their basal insulin therapy. Compared with premixed insulin, target attainment was similar with bolus insulin and higher with GLP-1 receptor agonists.

Antibiotic treatment and mortality in patients with Listeria monocytogenes meningitis or bacteraemia

Invasive Listeria monocytogenes infections carry a high mortality despite antibiotic treatment. The rareness of the infection makes it difficult to improve antibiotic treatment through randomized clinical trials. This observational study investigated clinical features and outcome of invasive L. monocytogenes infections including the efficacy of empiric and definitive antibiotic therapies. Demographic, clinical and biochemical findings, antibiotic treatment and 30-day mortality for all episodes of L. monocytogenes bacteraemia and/or meningitis were collected by retrospective medical record review in the North Denmark Region and the Capital Region of Denmark (17 hospitals) from 1997 to 2012. Risk factors for 30-day all-cause mortality were assessed by logistic regression. The study comprised 229 patients (median age: 71 years), 172 patients had bacteraemia, 24 patients had meningitis and 33 patients had both. Significant risk factors for 30-day mortality were septic shock (OR 3.0, 95% CI 1.4-6.4), altered mental state (OR 3.6, 95% CI 1.7-7.6) and inadequate empiric antibiotic therapy (OR 3.8, 95% CI 1.8-8.1). Cephalosporins accounted for 90% of inadequately treated cases. Adequate definitive antibiotic treatment was administered to 195 patients who survived the early period (benzylpenicillin 72, aminopenicillin 84, meropenem 28, sulfamethoxazole/trimethoprim 6, and piperacillin/tazobactam 5). Definitive antibiotic treatment with benzylpenicillin or aminopenicillin resulted in a lower 30-day mortality in an adjusted analysis compared with meropenem (OR 0.3; 95% CI 0.1-0.8). In conclusion, inadequate empiric antibiotic therapy and definitive therapy with meropenem were both associated with significantly higher 30-day mortality.

Gender differences in the outcome of community-acquired Staphylococcus aureus bacteraemia: a historical population-based cohort study

OBJECTIVES

Female gender has been suggested to be associated with poor outcome in patients with Staphylococcus aureus bacteraemia (SAB), but existing data remain sparse and conflicting. We investigated clinical outcomes in female and male patients with community-acquired (CA-) SAB.

METHODS

Population-based medical registers were used to conduct a cohort study of all adult patients with CA-SAB in northern Denmark, 2000-2011. Thirty-day mortality after CA-SAB for female and male patients was estimated by the Kaplan-Meier method. Using Cox proportional hazards regression, we computed hazard ratios (HRs) of death according to gender, overall and stratified by age groups, co-morbidity level, and selected major diseases while adjusting for potential confounders. Moreover, we estimated 30-day prevalence proportions for SAB-associated infective endocarditis and osteomyelitis by gender.

RESULTS

Among 2638 patients with CA-SAB, 1022 (39%) were female. Thirty-day mortality was 29% (n = 297) in female patients and 22% (n = 355) in male patients, yielding an adjusted HR (aHR) of 1.30 (95% CI, 1.11-1.53). This association appeared robust across age groups, whereas no consistent pattern was observed according to co-morbidity level. Compared with male patients, the prognostic impact of gender was most pronounced among female patients with diabetes (aHR 1.52; 95% CI 1.04-2.21)), and among female patients with cancer (aHR 1.40; 95% CI 1.04-1.90). The 30-day prevalence of infective endocarditis or osteomyelitis did not differ according to gender.

CONCLUSION

Female patients with CA-SAB experienced increased 30-day mortality compared with male patients. Gender should be considered in the triage and risk stratification of CA-SAB patients.

Precision medicine in the age of big data: The present and future role of large-scale unbiased sequencing in drug discovery and development

High throughput molecular and functional profiling of patients is a key driver of precision medicine. DNA and RNA characterization has been enabled at unprecedented cost and scale through rapid, disruptive progress in sequencing technology, but challenges persist in data management and interpretation. We analyze the state-of-the-art of large-scale unbiased sequencing in drug discovery and development, including technology, application, ethical, regulatory, policy and commercial considerations, and discuss issues of LUS implementation in clinical and regulatory practice.

Tuberculosis and risk of cancer: a Danish nationwide cohort study

OBJECTIVES

To investigate the short- and long-term risk of cancer in patients with active tuberculosis (TB).

DESIGN

Using Danish nationwide databases, we quantified cancer risk in TB patients during 1978-2011 compared with the general population.

RESULTS

We observed 1747 cancers in 15 024 TB patients (median follow-up 8.5 years), reflecting a standardised incidence ratio (SIR) of 1.52 (95%CI 1.45-1.59). All-time SIR for extra-pulmonary cancer was 1.29 (95%CI 1.22-1.36) and for lung cancer it was 3.40 (95%CI 3.09-3.74). Absolute cancer risk 3 months after TB was 1.83% (SIR 11.09, 95%CI 9.82-12.48), with highly increased SIRs for malignant pleural mesothelioma (368.4), lung cancer (40.9), Hodgkin's lymphoma (30.6), ovarian cancer (26.4) and non-Hodgkin's malignant lymphoma (23.8). Between the 3-month and 5-year follow-up, the SIR for any cancer was 1.59 (95%CI 1.46-1.72), including 19- and 3-fold increases for malignant pleural mesothelioma and lung cancer. Beyond 5 years, the SIR of cancer was 1.17 (95%CI 1.10-1.25). Elevated long-term risks persisted for haematological (SIR 1.34, 95%CI 1.01-1.74) and tobacco-related cancers (SIR 1.78, 95%CI 1.60-1.97).

CONCLUSION

TB is a marker of occult lung cancer and several extra-pulmonary cancers. TB also predicts increased long-term risk of cancer, possibly related to chronic inflammation and shared risk factors, including immunosuppression and smoking.

Trends in length of stay, mortality and readmission among patients with community-acquired bacteraemia

In patients hospitalized with severe infection, premature discharge may lead to increased risk of readmission and death. We conducted this population-based cohort study to examine trends in length of stay (LOS) and 30-day mortality and hospital readmission rates after bacteraemia from 1994 through 2013. We used Cox regression to compute hazard ratios (HRs) for 30-day mortality and 30-day postdischarge readmission rates by calendar period and quintiles of LOS, adjusting for age, sex and comorbidity. Among 7618 patients hospitalized with community-acquired bacteraemia during the study period, median LOS decreased from 12 days (quartiles 7-21 days) in 1994-1998 to 9 days (quartiles 6-16 days) in 2009-2013 (25% relative reduction). The 30-day mortality fell from 16.7% to 15.0%, yielding an adjusted 30-day HR of 0.80 (95% confidence interval (CI) 0.68-0.95). Almost one fifth (19.4%) of patients discharged alive were readmitted within 30 days. Concurrently, the adjusted HR of readmission tended to increase (adjusted HR 1.09, 95% CI 0.93-1.28) in 2009-2013 compared with 1994-1998. Compared with the middle quintile of LOS (9-12 days), the risk of readmission was slightly higher for patients discharged within 5 days (adjusted HR 1.12, 95% CI 0.92-1.37), especially for readmission due to infection (adjusted HR 1.38, 95% CI 1.03-1.85). Readmission risk was lowest for 6 to 8 days LOS (adjusted HR 0.80, 95% CI 0.67-0.95) and highest for LOS ≥23 days (adjusted HR 1.30, 95% CI 1.11-1.53). The declining LOS after community-acquired bacteraemia between 1994 and 2013 was not accompanied by increased 30-day mortality but by slightly increased readmission rates.

A novel CO2- and SO2-tolerant dual phase composite membrane for oxygen separation

Here we report a novel, cheap, non-toxic, CO₂- and SO₂-stable dual phase composite oxygen transport membrane (Al_0.02Ga_0.02Zn_0.96O_1.02–Gd_0.1Ce_0.9O_1.95−δ) for oxygen separation.

Case fatality ratio and mortality rate trends of community-onset Staphylococcus aureus bacteraemia

Lethal outcomes can be expressed as a case fatality ratio (CFR) or as a mortality rate per 100 000 population per year (MR). Population surveillance for community-onset methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus bacteraemia was conducted in Canada, Australia, Sweden and Denmark to evaluate 30-day CFR and MR trends between 2000 and 2008. The CFR was 20.3% (MSSA 20.2%, MRSA 22.3%) and MR was 3.4 (MSSA 3.1, MRSA 0.3) per 100 000 per year. Although MSSA CFR was stable the MSSA MR increased; MRSA CFR decreased while its MR remained low during the study. Community-onset S. aureus bacteraemia, particularly MSSA, is associated with major disease burden. This study highlights complementary information provided by evaluating both CFR and MR.

Incidence, clinical characteristics and 30-day mortality of enterococcal bacteraemia in Denmark 2006-2009: a population-based cohort study

Enterococci currently account for approximately 10% of all bacteraemias, reflecting remarkable changes in their epidemiology. However, population-based data of enterococcal bacteraemia are scarce. A population-based cohort study comprised all patients with a first episode of Enterococcus faecalis or Enterococcus faecium bacteraemia in two Danish regions during 2006-2009. We used data collected prospectively during clinical microbiological counselling and hospital registry data. We determined the incidence of mono- and polymicrobial bacteraemia and assessed clinical and microbiological characteristics as predictors of 30-day mortality in monomicrobial bacteraemia by logistic regression analysis. We identified 1145 bacteraemic patients, 700 (61%) of whom had monomicrobial bacteraemia. The incidence was 19.6/100 000 person-years (13.0/100 000 person-years for E. faecalis and 6.6/100 000 person-years for E. faecium). The majority of bacteraemias were hospital-acquired (E. faecalis, 45.7%; E. faecium, 85.2%). Urinary tract and intra-abdominal infections were the predominant foci for the two species, respectively. Infective endocarditis (IE) accounted for 25% of patients with community-acquired E. faecalis bacteraemia. Thirty-day mortality was 21.4% in patients with E. faecalis and 34.6% in patients with E. faecium. Predictors of 30-day mortality included age, co-morbidity and hospital-acquired bacteraemia. In addition, intra-abdominal infection, unknown focus and high-level gentamicin resistance were predictors of mortality in E. faecalis patients. E. faecium was associated with increased risk of mortality compared with E. faecalis. The study emphasizes the importance of enterococci both in terms of incidence and prognosis. The frequency of IE in patients with E. faecalis bacteraemia emphasizes the importance of echocardiography, especially in community-acquired cases.

The changing epidemiology of Staphylococcus aureus bloodstream infection: a multinational population-based surveillance study

Although the epidemiology of Staphylococcus aureus bloodstream infection (BSI) has been changing, international comparisons are lacking. We sought to determine the incidence of S. aureus BSI and assess trends over time and by region. Population-based surveillance was conducted nationally in Finland and regionally in Canberra, Australia, western Sweden, and three areas in each of Canada and Denmark during 2000-2008. Incidence rates were age-standardized and gender-standardized to the EU 27-country 2007 population. During 83 million person-years of surveillance, 18,430 episodes of S. aureus BSI were identified. The overall annual incidence rate for S. aureus BSI was 26.1 per 100,000 population, and those for methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) were 24.2 and 1.9 per 100,000, respectively. Although the overall incidence of community-onset MSSA BSI (15.0 per 100,000) was relatively similar across regions, the incidence rates of hospital-onset MSSA (9.2 per 100,000), community-onset MRSA (1.0 per 100,000) and hospital-onset MRSA (0.8 per 100,000) BSI varied substantially. Whereas the overall incidence of S. aureus BSI did not increase over the study period, there was an increase in the incidence of MRSA BSI. Major changes in the occurrence of community-onset and hospital-onset MSSA and MRSA BSI occurred, but these varied significantly among regions, even within the same country. Although major changes in the epidemiology of community-onset and hospital-onset MSSA and MRSA BSIs are occurring, this multinational population-based study did not find that the overall incidence of S. aureus BSI is increasing.

Direct identification of major blood culture pathogens, including Pseudomonas aeruginosa and Escherichia coli, by a panel of fluorescence in situ hybridization assays using peptide nucleic acid probes

Rapid identification of four major pathogens from 1,231 positive blood cultures by fluorescence in situ hybridization with peptide nucleic acid probes (AdvanDx Inc., Woburn, Mass.) was evaluated. For Escherichia coli, Staphylococcus aureus, and Candida albicans results agreed with conventional identification. The lower sensitivity of the Pseudomonas aeruginosa assay should not compromise the utility of the four assays.

Treatment with tumor-reactive Fab-IL-2 and Fab-staphylococcal enterotoxin A fusion proteins leads to sustained T cell activation, and long-term survival of mice with established tumors

C215Fab-IL-2 fusion protein, with full IL-2 and antigen binding activity, was produced in E. coli at high level (>50 mg/l). When co-administered with Fab-superantigen fusion protein (C215Fab-SEA) in mice strong and sustained T cell activation was observed. Combination treatment of mice carrying B16 melanoma transfected with C215 antigen was also more efficient than using C215Fab-SEA (p<0.01) or C215Fab-IL-2 alone (p<0.001). In a long-term survival experiment 5/12 mice having received combination treatment 5 days after i.v. inoculation of B16 cells survived >85 days. Improved therapeutic efficacy correlated with increased tumor infiltration by activated CD25+ T cells, indicating a T cell mediated mechanism.

The distinct role of CD4+ and CD8+ T-cells during the anti-tumour effects of targeted superantigens

To target T-cells to the tumour area we created a recombinant protein of the bacterial superantigen (SAg) Staphylococcal enterotoxin A (SEA) and the Fab-fragment of a tumour-reactive antibody. This antibody-targeted SAg immunotherapy therapy has been shown to be highly efficient, eliminating > 95% of the pulmonary metastasis in mice carrying established melanoma micrometastases. Earlier studies demonstrated that elimination of the C215-expressing B16-melanoma lung metastasis was dependent on interferon (IFN)-gamma release and expression of perforin. In the present study, therapeutic effector functions were analysed both locally at the tumour site and systemically in the spleen. In order to elucidate the role of each T-cell subset during Fab-SEA therapy, CD4 knock-out (KO) and CD8 KO mice were used. Tumour size reduction was statistically significant in Fab-SEA-based tumour therapy in both types of T-cell-deficient mice compared to wild-type mice. CD4 KO mice displayed a drastic reduction in the number of tumour-infiltrating macrophages and CD8+ T-cells. Therapy-induced accumulation of perforin-containing cells at the tumour site was significantly impaired in CD8 KO mice, and marginally in CD4 KO mice. Moreover, CD4 KO mice failed to produce substantial amounts of the tumour suppressive cytokine IFN-gamma. This is in sharp contrast to normal mice where a massive local release was recorded. CD8 KO mice displayed a spontaneous production of interleukin (IL)-4 and IL-10 locally in the tumour. Neither normal nor CD4 KO mice produced detectable levels of these Th-2-associated cytokines. The high level of IL-10 was demonstrated to inhibit Fab-SEA tumour therapy, since the therapeutic efficacy was significantly higher in IL-10 KO mice. These results illustrate the importance of a finely tuned cellular collaboration to regulate the various phases of an efficient anti-tumour immune response.

Long-term survival and complete cures of B16 melanoma-carrying animals after therapy with tumor-targeted IL-2 and SEA

The bacterial superantigen (SAg) staphylococcal enterotoxin A (SEA) is a potent inducer of CTL activity and cytokine production in vivo. To engineer SAg for cancer immunotherapy, we genetically fused SEA to a Fab fragment of the C215 tumor-reactive antibody. Strong reduction of lung metastasis was seen in mice carrying established lung metastases of the poorly immunogenic B16-C215 melanoma after Fab-SEA therapy. However, important anti-tumor effector functions, such as IFN-gamma secretion and CTL activity, gradually declined during therapy. In this study, we show that Fab-SEA immunotherapy is strongly potentiated by Fab-IL-2 co-administration. Combined Fab-IL-2 and Fab-SEA therapy prolongs the immune response in vivo, limits the development of immunological unresponsiveness and promotes maximal anti-tumor effects. Significantly prolonged survival was noted in tumor-carrying animals treated with Fab-SEA/Fab-IL-2 as compared with Fab-SEA or Fab-IL-2 alone. Combination therapy resulted in complete cure in 90% of tumor-bearing animals, whereas only 10% long-term survival was seen in Fab-SEA or Fab-IL-2-treated animals. Single Fab-SEA therapy induced a hyporesponsive state after 2 cycles of treatment. In contrast, the immune response after combination therapy was characterized by substantially augmented IFN-gamma and TNF-alpha production and strong CTL activity. Our data demonstrate that combined Fab-SEA and Fab-IL-2 therapy prolongs the immune response in vivo and induced long-term survival of more than 90% of the animals carrying the highly aggressive B16 melanoma.

Gos1p, a Saccharomyces cerevisiae SNARE protein involved in Golgi transport

Specific transport between secretory compartments requires that vesicular carriers contain targeting proteins known as SNAREs. Ten v-SNAREs have been identified in the genome of the yeast Saccharomyces cerevisiae by sequence analysis. We report here the characterization of Gos1p, a v-SNARE localized to the Golgi compartment and likely homolog of the mammalian protein GOS-28/GS28. Gos1p is a type II membrane protein with characteristic SNARE sequence hallmarks and is functionally a SNARE protein. Gos1p was originally identified as a 28 kDa protein in an immunoprecipitate of the cis-Golgi t-SNARE Sed5p. This interaction between Sed5p and Gos1p is direct as demonstrated by in vitro binding with recombinant proteins. Deletion of GOS1 results in viable haploids with modest growth and secretory defects. Close examination of the secretory phenotype of GOS1-disrupted cells suggests that Gos1p may play a role in multiple transport steps, specifically ER-Golgi and/or intra-Golgi transport.

Molecular structure of a barley alpha-amylase-inhibitor complex: implications for starch binding and catalysis

alpha-Amylases are widely occurring, multidomain proteins with a catalytic (beta/alpha)8-barrel. In barley alpha-amylase, insight into the catalytic mechanism is gained from the X-ray crystal structure of its molecular complex with acarbose, a pseudotetrasaccharide that acts like a transition-state analogue and which is shown to bind at two specific regions of the enzyme. The structure of the complex has been refined to an R-factor of 15.1% for all observations with Fo>sigma(Fo) between 10 and 2.8 A resolution. A difference Fourier map produced after refinement of the native structure against the data of the acarbose complex clearly revealed density corresponding to two oligosaccharide-binding sites. One of these is defined as the surface-located starch granule-binding site characteristic of cereal alpha-amylases. It involves stacking of two acarbose rings on Trp276 and Trp277. The other binding region is the active site covering subsites -1, +1 and +2. Here, Glu204 is positioned to act in general acid/base catalysis protonating the glucosidic oxygen atom assisted by Asp289. A water molecule that bridges Glu204 and Asp289 is found at the entrance cavity containing a total of five water molecules. This water molecule is proposed to reprotonate Glu204 and supply the hydroxyl ion for nucleophilic attack on the glucosyl C1 atom. Asp 179 acts as the nucleophile that can bind covalently to the substrate intermediate after bond cleavage. The present complex structure together with the conservation of active-site residues among alpha-amylases and related enzymes, are consistent with a common catalytic mechanism for this class of retaining carbohydrases.

A rab protein is required for the assembly of SNARE complexes in the docking of transport vesicles

Rab proteins are generally required for transport vesicle docking. We have exploited yeast secretion mutants to demonstrate that a rab protein is required for v-SNAREs and t-SNAREs to assemble. The absence of the rab protein in the docking complex suggests that, in a broad sense, rab proteins participate in a reaction catalyzing SNARE complex assembly. In so doing, rab proteins could help impart an additional layer of specificity to vesicle docking. This mechanism likely involves the Sec1 homolog Sly1, which we identified in isolated docking complexes. We also report the identification of a novel v-SNARE (Ykt6p) component of the yeast ER-Golgi docking complex that has a CAAX box and is predicted to be lipid anchored. The surprising finding that docking complexes can contain many distinct species of SNAREs (Sed5p, Bos1p, Sec22p, Ykt6p, and likely Bet1p, p28, and p14) suggests that multimeric interactions are features of the fusion machinery, and may also improve the fidelity of vesicle targeting.

Localization of an O-glycosylated site in the recombinant barley alpha-amylase 1 produced in yeast and correction of the amino acid sequence using matrix-assisted laser desorption/ionization mass spectrometry of peptide mixtures

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) of peptide mixtures was used to characterize recombinant barley alpha-amylase 1, produced in yeast. Three peptide mixtures were generated by cleavage with CNBr, digestion with endoproteinase Lys-C and Asp-N, respectively, and analyzed directly by MALDI-MS. Based on the three mass spectrometric peptide maps, an error in the sequence deduced from cDNA, resulting in a mass difference of 28 Da, was located to a sequence stretch of 5 amino acid residues; furthermore, a dihexose substituent was identified on Thr410. Subsequent Edman degradation of two selected peptides isolated from the endoproteinase Lys-C digest corrected the sequence to be Val instead of Ala in position 284 and confirmed the O-glycosylation. These results demonstrate that the direct peptide mixture analysis by MALDI-MS is a rapid and sensitive method for protein characterization and provides valuable information before further characterization.

Production of active, insect-specific scorpion neurotoxin in yeast

A cDNA encoding the Androctonus australis Hector insect toxin 1 (AaH IT1) was expressed in yeast leading to secretion of fully biologically active protein. Three different multicopy plasmids were constructed using PCR. Expression was directed by the strong PGK1 promoter of the yeast vector pMA 91. Plasmid pMA 91-AaH IT1 encodes AaH IT1 and its own signal peptide. In the two other constructions, the cDNA encoding the mature part of AaH IT1 is fused to the prepro-signal sequence of the yeast alpha-mating-factor precursor; the pBAL 7-alpha-KREAEA-AaH IT1 includes the cDNA sequence encoding the KR(EAEA) processing sequence of the alpha-mating factor, and pBAL 7-alpha-KR-AaH IT1 encodes the KR fused directly to the AaH IT1 gene. The yeast alpha-mating-factor signal peptide launched the pro-alpha-mating-factor-AaH IT1 fusion protein into the secretory pathway. The fusion proteins are expected to be cleaved in the Golgi by the KEX2 endopeptidase and the STE13 dipeptidyl aminopeptidase, leading to release of mature AaH IT1. Pulse/chase labelling of transformed yeast protoplasts, followed by SDS/PAGE analysis of proteins immunoprecipitated from either the lysate or the extracellular fluid, showed that AaH IT1 was produced. The highest concentration of recombinant AaH IT1 in the culture medium, as determined using a 125I-AaH IT1 specific radioimmunoassay, was 4 micrograms/l (0.5 nM). The recombinant toxin was fully biologically active against cockroaches as assessed by injection and comparison to native AaH IT1. Moreover, it competed with radiolabelled native toxin for its receptor on the voltage-sensitive Na+ channel with a dissociation constant of 0.5 nM.

Domain B protruding at the third beta strand of the alpha/beta barrel in barley alpha-amylase confers distinct isozyme-specific properties

alpha-Amylases belong to the alpha/beta-barrel protein family in which the active site is created by residues located at the C-terminus of the beta strands and in the helix-connecting loops extending from these ends. In the alpha-amylase family, a small separate domain B protrudes at the C-terminus of the third beta strand of the (beta/alpha)8-barrel framework. The 80% identical barley alpha-amylase isozymes 1 and 2 (AMY1 and AMY2, respectively) differ in substrate affinity and turnover rate, CaCl2 stimulation of activity, sensitivity to the endogenous 21-kDa alpha-amylase/subtilisin inhibitor, and stability at low pH. To identify regions that confer these isozyme-specific variations, AMY1-AMY2 hybrid cDNAs were generated by in vivo homologous recombination in yeast. The hybrids AMY1-(1-90)-AMY2-(90-403) and AMY1-(1-161)-AMY2-(161-403) characterized in this study contain the 90-residue and 161-residue N-terminal sequences, respectively, of AMY1 and complementary C-terminal regions of AMY2. AMY1-(1-90)-AMY2-(90-403) comprises the 60-amino-acid domain B of AMY2 and resembles this isozyme in sensitivity to alpha-amylase/subtilisin inhibitor and its low affinity for the substrates p-nitrophenyl alpha-D-maltoheptaoside, amylose and the inhibitor acarbose. Only AMY1-(1-161)-AMY2-(161-403) and AMY1, which both share domain B, are stable at low pH. However, AMY2 and both hybrid AMY species, but not AMY1, show maximum enzyme activity on insoluble blue starch at approximately 10 mM CaCl2. Domain B thus determines several functional and stability properties that distinguish the barley alpha-amylase isozymes.

Site-directed mutagenesis of histidine 93, aspartic acid 180, glutamic acid 205, histidine 290, and aspartic acid 291 at the active site and tryptophan 279 at the raw starch binding site in barley alpha-amylase 1

The pseudotetrasaccharide acarbose has high affinity for the active site (Ki,app = 1 microM) and low affinity for a secondary site (Kd = 2.3 mM) in barley alpha-amylase 1, distinguished by inhibition kinetics and spectral perturbation. Mutants of putative catalytic residues, D180N, E205Q, and D291N, are inactive and display low affinity for acarbose-Sepharose. H93N and H290N mutants, at invariant residues, have kcat/Km for p-nitrophenylmaltoheptaoside of 0.3 and 1.2% of wild-type. A corresponding 370- and 85-fold increased Ki,app for acarbose and a lack of shifts in pH activity profiles indicate that these histidines participate in transition state stabilization but not directly in catalysis. This finding agrees with H bonding to OH groups of the valienamine ring of acarbose in the three-dimensional structure. Loss of inhibition above pH 6 supports that acarbose is most potent in protonated form. The low affinity site contains Trp278 and Trp279, known to bind cyclomaltoheptaose. While the W279A mutant has 10-fold decreased affinity for starch granules, production of Trp278 mutants failed. The invariant Trp278 is perhaps critical for stability or folding in cereal alpha-amylases.

Electrospray mass spectrometry characterization of post-translational modifications of barley alpha-amylase 1 produced in yeast

We have used electrospray mass spectrometry (ESMS) in combination with protein chemistry and genetics to delineate post-translational modifications in yeast of barley alpha-amylase 1 (AMY1), a 45 kD enzyme crucial for production of malt, an important starting material in the manufacture of beer and whisky. In addition to signal peptide processing these modifications are: (1) removal of C-terminal Arg-Ser by Kex1p, (2) glutathionylation of Cys95, (3) O-glycosylation, and (4) additional degradation of the C-terminus.

Comparison of barley malt alpha-amylase isozymes 1 and 2: construction of cDNA hybrids by in vivo recombination and their expression in yeast

Germinating barley produces two alpha-amylase isozymes, AMY1 and AMY2, having 80% amino acid (aa) sequence identity and differing with respect to a number of functional properties. Recombinant AMY1 (re-AMY1) and AMY2 (re-AMY2) are produced in yeast, but whereas all re-AMY1 is secreted, re-AMY2 accumulates within the cell and only traces are secreted. Expression of AMY1::AMY2 hybrid cDNAs may provide a means of understanding the difference in secretion efficiency between the two isozymes. Here, the efficient homologous recombination system of the yeast, Saccharomyces cerevisiae, was used to generate hybrids of barley AMY with the N-terminal portion derived from AMY1, including the signal peptide (SP), and the C-terminal portion from AMY2. Hybrid cDNAs were thus generated that encode either the SP alone, or the SP followed by the N-terminal 21, 26, 53, 67 or 90 aa from AMY1 and the complementary C-terminal sequences from AMY2. Larger amounts of re-AMY are secreted by hybrids containing, in addition to the SP, 53 or more aa of AMY1. In contrast, only traces of re-AMY are secreted for hybrids having 26 or fewer aa of AMY1. In this case, re-AMY hybrid accumulates intracellularly. Transformants secreting hybrid enzymes also accumulated some re-AMY within the cell. The AMY1 SP, therefore, does not ensure re-AMY2 secretion and a certain portion of the N-terminal sequence of AMY1 is required for secretion of a re-AMY1::AMY2 hybrid.

C-terminal processing of barley alpha-amylase 1 in malt, aleurone protoplasts, and yeast

C-terminal processing of low pI barley alpha-amylase (AMY1) results in multiple forms in malt, aleurone protoplasts, and transformed yeast. Expression of an AMY1 cDNA in yeast thus leads to four secreted forms with distinct pI values between 4.7 and 5.1 and essentially identical Mr. AMY1-1 and AMY1-2 lacking the C-terminal Arg-Ser are generated by carboxypeptidase in vitro from AMY1-3 and AMY1-4, respectively. In vivo processing is due to the KEX1-encoded yeast carboxypeptidase. AMY1-2 and AMY1-4 are fully active, whereas AMY+-1 and AMY1-3 retain 3-4% activity toward p-nitrophenyl maltoheptaoside and have one fewer SH group, due to reaction with glutathione. AMY1-1-AMY1-4 are indistinguishable from malt AMY1 with respect to Ca(2+)-, substrate-, and beta-cyclodextrin-binding as well as recognition by three monoclonal antibodies and limited proteolysis by proteinase K. Transient AMY1 precursors present in barley aleurone protoplasts were trapped by addition of serine carboxypeptidase inhibitors, indicating that endogenous carboxypeptidase participates in the maturation of AMY1 during germination. Three pairs of precursor/mature AMY1 forms are recognized, presumably corresponding to the three genes encoding AMY1. Malt carboxypeptidase II can convert in vitro the precursors isolated from protoplasts into processed enzyme, and AMY1 from malt accordingly lacks the C-terminal heptapeptide. This report thus demonstrates posttranslational protein modification by carboxypeptidase in higher plants.

Expression of cDNAs encoding barley alpha-amylase 1 and 2 in yeast and characterization of the secreted proteins

Amylolytic strains of the yeast, Saccharomyces cerevisiae, were constructed by transformation with expression plasmids containing cDNAs encoding either AMY1 (clone E) or AMY2 (clone pM/C). The alpha-amylases were efficiently secreted into the culture medium directed by their own signal peptides. When clone E without its 5'-noncoding region was expressed from the yeast PGK promoter, AMY1 was produced as 1% of total cell protein and was thus the major protein secreted, whereas a similar construct derived from pM/C produced much less AMY2. This level is the highest reported for a plant protein secreted by yeast as mediated by the endogenous signal peptide. Production of AMY1 increased 25-fold when the 5'-noncoding part of clone E which contains a 12-bp dG.dC homopolymer tail had been removed. Moreover, expression was one to two orders of magnitude higher when genes encoding AMY1 or AMY2 were inserted between promoter and terminator of the yeast PGK gene in comparison to expression directed from the ADC1 or GAL1 promoters. Recombinant AMY1 and AMY2 had the same Mr and N-terminal sequence as the corresponding barley malt enzymes. Furthermore, none of the enzymes were found to be N-glycosylated. Isoelectric focusing indicated that transformed yeast cells secreted one major form of AMY2 and four dominant forms of AMY1. One AMY1 form corresponded to one of the major forms found in malt while the others, having either low activity or unusually high pI, probably reflect inefficient/incorrect processing. Enzyme kinetic properties and pH activity-dependence of recombinant AMY2 were essentially identical to those of malt AMY2.(ABSTRACT TRUNCATED AT 250 WORDS)