The success rate and complications of midline catheters in pediatric outpatient parenteral antibiotic therapy (OPAT)

The use of outpatient parenteral antimicrobial therapy (OPAT) for children has several advantages, including reduced length of hospital stay and costs. A reliable vascular access is key to delivering safe and effective pediatric OPAT. In recent years, midline catheters (MC) have been increasingly used for short-term intravenous antibiotic therapy in children. However, there are no studies investigating the use of MCs in the OPAT setting. The main aim of this paper was to evaluate the success and complications of using MCs for pediatric OPAT. This was a retrospective cohort study from a tertiary academic pediatric hospital. All MCs inserted at the hospital and used for OPAT were eligible for study inclusion. The primary objective was to describe the percentage of patients able to complete OPAT without the need for additional venous access. Forty-one MCs were included in the study. Patient mean (SD) age was 5.9 (4.9) years. In 31 cases (76%, 95% CI 62-86%), the iv therapy could be successfully completed using only the MC. Imbalances between the groups suggested unfavorable outcome for saphenous vein catheters as well as for shorter and smaller-sized catheters. Fourteen patients (34%) were subjected to a MC-related complication. Pain on injection in the MC was the most frequent complication (n = 10, 24%).    Conclusion: Midline catheters could be an alternative to central venous access for pediatric OPAT. Avoiding saphenous vein insertion and using longer and larger-sized catheters could increase MC success rate. No severe MC-related complication was found. Further randomized studies comparing different catheter types are needed. What is Known: • For selected patients, pediatric outpatient parenteral antimicrobial therapy (OPAT) is safe and provides health-economic, psychosocial, and medical advantages compared to in-hospital care. • A reliable venous access is one of the key factors to the success of OPAT, but this can be a challenge in children. What is New: • Using midline catheters, 76% of patients could complete their intended iv therapy without the need for additional venous access. Avoiding saphenous vein insertion and using longer and larger-sized catheters could increase the success rate. • Thirty-four percent of catheters were subject to some kind of complication, the most common being pain on injection in the catheter.

Complications of Pediatric Midline Catheters: A Prospective Observational Pilot Study

BACKGROUND

Midline catheters are peripheral intravenous (IV) catheters in which the tip of the catheter does not reach the central circulation. In children, the use of midline catheters could lead to decreased complications from central venous catheters. To validate the safety of midline catheter use in children, we aimed to describe the complications and dwell time of pediatric midline catheters. The primary outcome was the incidence of catheter-related venous thromboembolism (VTE).

METHODS

We conducted an observational, prospective study including consecutive patients at a tertiary multidisciplinary pediatric hospital. One hundred pediatric midline catheters were followed for thrombotic, infectious, and mechanical complications. After catheter removal, Doppler ultrasonography was performed to detect asymptomatic VTE.

RESULTS

The mean age was 6.0 years (standard deviation [SD], 4.7), and median catheter dwell time was 6 (4-8) days. Most midline catheters were inserted in arm veins, most commonly in the basilic vein (56%). Catheter-related VTE was diagnosed in 30 (30%; 95% confidence interval [CI], 21%-40%) cases, corresponding to an incidence rate of 39 (95% CI, 26-55) cases per 1000 catheter days. Eight of 14 saphenous vein catheters were complicated by VTE compared to 22 of 86 arm vein catheters, suggesting an imbalance in favor of arm vein insertion site. Two patients needed anticoagulation therapy due to catheter-related VTE. Thirty (30%) catheters were removed unintentionally or due to complications, 22 of these needed additional IV access to complete the intended therapy. No catheter-related bloodstream infection (95% CI, 0%-4%) occurred. Mechanical complications occurred in 33 (33%; 95% CI, 24%-43%) midline catheters.

CONCLUSIONS

In children, thrombotic and mechanical complications of midline catheters are common, but only few VTEs are severe enough to warrant anticoagulation therapy. Systemic infectious complications are rare. Seventy-eight percent of patients did not need additional venous access to complete short-term IV therapy. Considering the rate of clinically relevant complications and the catheter dwell time, pediatric midline catheters could be an alternative to central venous access for short-term (5-10 days) IV therapy.

Supraglottoplasty for severe laryngomalacia can be effective and safe also in children with high-risk comorbidities - Experience from a tertiary center

OBJECTIVES

Supraglottoplasty (SGP) for severe laryngomalacia (LM) in children with medical comorbidities has been associated with high risk of surgical failure and increased need of postoperative pediatric intensive care unit (PICU) intervention, but evidence for this is ambiguous. The objective was to evaluate surgical outcome and risk of need for PICU-intervention following SGP for severe LM in comorbid patients.

METHODS

Retrospective observational study of 116 patients treated with SGP for severe LM between 2000 and 2021 at a tertial referral pediatric airway surgery center Karolinska University Hospital. Medical records were reviewed and patient data regarding surgical timing, type of SGP procedure, PICU-intervention, complications, and outcomes were recorded. Patients were defined as non-comorbid vs high-risk comorbid (HRC) based on a coexisting comorbidity for risk of surgical failure and postoperative PICU-intervention. Surgical failure was defined as need of revision surgery, tracheostomy or assisted ventilation (continuous positive airway pressure and bilevel positive airway pressure). PICU intervention was defined as need of postoperative assisted ventilation or intubation. Statistical comparisons were performed with outcome of SGP on children with LM and no comorbidities.

RESULTS

41/116 patients included had a HRC associated with an increased risk of PICU-intervention and surgical failure. 75/116 patients were defined as non-comorbid. The overall surgical success in the study population was 89.7% (104/116), 94.7% in the non HRC group vs 80.5% in the HRC-group. 5/41 HRC patients and 1/75 non-comorbid patients needed SGP revision in which 5/6 was successful. There was no significantly increased need for postoperative PICU intervention in HRC patients.

CONCLUSION

SGP for severe LM patients with high-risk comorbidities performed in a tertiary setting had an overall good result and low risk of PICU-intervention. Revision SGP was more common in HRC patients but had a good outcome. Multidisciplinary experience in perioperative care of comorbid patients may be of key importance for outcome and children with high-risk comorbidities should thus not be withheld the possible benefit of SGP without assessment at a tertiary pediatric airway center.

Dose-dependent relationship between nocturnal gastroesophageal reflux and chronic rhinosinusitis in a middle-aged population: results from the SCAPIS pilot

BACKGROUND

Gastroesophageal reflux (GER) has been associated with several upper- and lower-airway diseases. It would be plausible if nightly occurring reflux via laryngopharyngeal reflux (LPR) might affect the upper airways. Still, the role of nocturnal gastroesophageal reflux (nGER) in chronic rhinosinusitis (CRS) is not fully established. The aim of this population-based study was to investigate the association between nGER and CRS.

METHODOLOGY

This cross-sectional population-based study comprises 1,111 randomly selected subjects from Gothenburg, Sweden, aged 50-64 years. The study is based on self-reported validated questionnaires. CRS was defined according to EPOS criteria. nGER was reported in relation to frequency.

RESULTS

CRS was more common among subjects with nGER than in those without (13 vs. 4.8%). There was a dose-response association between the frequency of nGER episodes and the risk of having CRS. In the logistic regression adjusted for (age, sex, BMI, educational level, smoking, and asthma). CRS was associated with nGER, OR 1.43 and the odds ratio increased if episodes were reported "almost every night", OR 4.6.

CONCLUSIONS

The study shows an association between nocturnal GER and CRS in a middle-aged population. The revealed dose dependency supports, though does not prove causality.

Demonstration of a compact deep UV Raman spatial heterodyne spectrometer for biologics analysis

Monoclonal antibodies and antibody fragments are increasingly important classes of biotherapeutics. However, these products are both challenging and expensive to manufacture. New process analytical technologies used to monitor these products during their manufacture are of significant interest. Deep UV Raman spectroscopy promises to provide the required specificity and accuracy, however instruments, have historically been large and complex. In this paper, a new deep UV Raman instrument is described using a solid-state laser and a spatial heterodyne spectrometer. The instrument overcomes practical limitations of the technique and could readily be used for online measurement. A series of observations have been made of biopharmaceutical products, including immunoglobulin G and domain antibodies. Where high levels of both specificity and linearity when measuring samples of different concentration with a precision of better than 0.05 mg/mL has been demonstrated.

Integrated continuous biomanufacturing on pilot scale for acid-sensitive monoclonal antibodies

In this study, we demonstrated the first, to our knowledge, integrated continuous bioprocess (ICB) designed for the production of acid-sensitive monoclonal antibodies, prone to aggregate at low pH, on pilot scale. A high cell density perfusion culture, stably maintained at 100 x 10⁶ cells/mL, was integrated with the downstream process, consisting of a capture step with the recently developed Protein A ligand, Z_Ca ; a solvent/detergent-based virus inactivation; and two ion exchange chromatography steps. The use of a mild pH in the downstream process makes this ICB suitable for the purification of acid-sensitive monoclonal antibodies. Integration and automation of the downstream process were achieved using the Orbit software, and the same equipment and control system were used in initial small-scale trials and the pilot-scale downstream process. High recovery yields of around 90% and a productivity close to 1 g purified antibody/L/day were achieved, with a stable glycosylation pattern and efficient removal of impurities, such as host cell proteins and DNA. Finally, negligible levels of antibody aggregates were detected owing to the mild conditions used throughout the process. The present work paves the way for future industrial-scale integrated continuous biomanufacturing of all types of antibodies, regardless of acid stability. This article is protected by copyright. All rights reserved.

Cancer Worry Distribution and Willingness to Undergo Colonoscopy at Three Levels of Hypothetical Cancer Risk—A Population-Based Survey in Sweden

Simple Summary

Cancer worry is a known health concern in cancer patients and people with a genetic predisposition to cancer. We measured how worried people, in general, are about developing cancer to describe levels in non-affected individuals. In total, 943 respondents completed a survey containing the Cancer Worry Scale (CWS) and hypothetical questions asking if they would attend a colonoscopy screening at a 5, 10, or 70 percent lifetime risk of developing bowel cancer. Unaffected individuals scored a mean of 9.46 on the six-item CWS. Women scored significantly higher than men (9.91 vs. 9.06). Women and parents had higher cancer worry than men and people without children when ruling out differences in education, age, and country of birth. People who worried more were also more inclined to undergo a colonoscopy screening, and intention increased with higher levels of hypothetical risk. These data may be helpful in future work on cancer worry and cancer prevention.

Abstract

Purpose: We describe levels of cancer worry in the general population as measured with the Cancer Worry Scale (CWS) and investigate the association with colonoscopy screening intentions in three colorectal cancer risk scenarios. Methods: The data were sourced through a population-based survey. Respondents (n = 943) completed an eight-item CWS and questions on colonoscopy screening interest at three hypothetical risk levels. Results: Respondents without a personal cancer history (n = 853) scored 9.46 on the six-item CWS (mean, SD 2.72). Mean scores were significantly higher in women (9.91, SD 2.89) as compared to men (9.06, SD 2.49, p < 0.001). Linear regression showed higher cancer worry in women and those with children when controlling for education, age group, and country of birth. High cancer worry (six-item CWS mean >12) was identified in 25% of women and in 17% of men. Among those, 71% would attend a colonoscopy screening compared to 52% of those with low cancer worry (p < 0.001, 5% CRC-risk). Conclusions: The distribution of cancer worry in a general population sample showed higher mean scores in women, and levels overlapped with earlier findings in cancer-affected samples. Respondents with high cancer worry were more inclined to undergo a colonoscopy screening, and intention increased with higher levels of hypothetical risk.

Incidence of venous thromboembolic events not related to vascular catheters in a prospective cohort of critically ill children

The risk for venous thromboembolism (VTE) is considered to be low in the general paediatric intensive care unit (PICU) population, and pharmacological thromboprophylaxis is not routinely used. PICU patients considered at high-risk of VTE could possibly benefit from pharmacological thromboprophylaxis, but the incidence of VTE in this group of patients is unclear. This was an observational, prospective study at a tertiary multi-disciplinary paediatric hospital. We used comprehensive ultrasonography screening for VTE in critically ill children with multiple risk factors for VTE. Patients admitted to PICU ≥ 72 h and with ≥ two risk factors for VTE were included. Patients receiving pharmacological thromboprophylaxis during their entire PICU stay were excluded. The primary outcome of the study was VTEs not related to the use of a CVC. Ultrasonography screening of the great veins was performed at PICU discharge. Seventy patients with median (interquartile range) 3 (2-4) risk factors for VTE were evaluated. Median age was 0.3 years (0.03-4.3) and median PICU length of stay 9 days (5-17). Regarding the primary outcome, no symptomatic VTEs occurred and no asymptomatic VTEs were found on ultrasonography screening, resulting in an incidence of VTEs not related to a vascular catheter of 0% (95% CI: 0-5.1%).

CONCLUSION

Our results indicate that VTEs not related to a vascular catheter are a rare event even in a selected group of severely ill small children considered to be at high risk of VTE.

WHAT IS KNOWN

• Children in the PICU often have several risk factors for venous thromboembolism (VTE). • The incidence of VTE in PICU patients is highly uncertain, and there are no evidence-based guidelines regarding VTE prophylaxis.

WHAT IS NEW

• This study found an incidence of VTEs not related to a vascular catheter of 0% (95% CI: 0-5.1%). • This indicates that such VTE events are rare even in PICU patients with multiple risk factors for VTE.

The Impact of Hospital Level of Care on the Management of Acute Cholecystitis: a Population-Based Study

BACKGROUND

The organization of healthcare could have an impact on the outcome of patients treated for acute cholecystitis (AC). The aim of this study was to analyze the way in which patients with AC are managed relative to the level of care by the treating hospital.

METHODS

Data were collected from the Swedish Register for Gallstone Surgery and ERCP (GallRiks). Cholecystectomies between 2010 and 2019 were included. The inclusion criterion was acute cholecystectomy in patients with AC operated at either tertiary referral centers (TRCs) or regional hospitals.

RESULTS

A total of 24,194 cholecystectomies with AC met the inclusion criterion. The time between admission and acute surgery was significantly elongated at TRCs compared with regional hospitals (2.2 ± 1.7 days vs. 1.6 ± 1.4 days, mean ± SD; p < 0.0001). Patients with a history of AC were more frequent at TRC (10.1% vs. 8.9%, p < 0.0056) and had a higher adverse event rate compared with those at regional hospitals (OR 1.61; CI 1.40-1.84, p < 0.0001). Surprisingly, an increased number of hospital beds correlated slightly with an increased number of days between admission and surgery (R² = 0.132; p = 0.0075).

CONCLUSION

Compared with regional hospitals, patients with AC had to wait longer at TRCs before surgery. A history of AC significantly increased the risk of adverse events. These findings indicate that logistic and organizational aspects of hospital care may affect the management of patients with AC. However, whether these findings can be generalized to healthcare organizations outside Sweden requires further investigation.

Thromboembolic Complications of Vascular Catheters Used for Pediatric Continuous Renal Replacement Therapy: Prevalence in a Single-Center, Retrospective Cohort

OBJECTIVES

Pediatric venous thromboembolic events are commonly associated with in situ central venous catheters. The risk for severe venous thromboembolism increases if a larger portion of the vessel lumen is occupied by the central venous catheter. A functioning vascular catheter is required when the continuous renal replacement therapy is used in critically ill children. Due to the high blood flow required for continuous renal replacement therapy, the external diameter of the catheter needs to be larger than a conventional central venous catheter used for venous access, potentially increasing the risk of venous thromboembolism. However, children on continuous renal replacement therapy often receive systemic anticoagulation to prevent filter clotting, possibly also preventing venous thromboembolism. The frequency of catheter-related venous thromboembolic events in this setting has not been described. Our main objective was to determine the prevalence of catheter-related venous thromboembolism in pediatric continuous renal replacement therapy.

DESIGN

Retrospective cohort study.

SETTING

Tertiary multidisciplinary academic pediatric hospital.

PATIENTS

Patients 0-18 years old with a vascular catheter used for continuous renal replacement therapy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In our series of 80 patients, we used 105 vascular catheters. The median age of the patients was 10 months and PICU mortality rate was 21%. Venous thromboembolic events were considered to be catheter related if located in the same vein as the vascular catheter and radiologically verified. Six (5.7%) catheter-related venous thromboembolic events were found. The clinically relevant complications of venous thromboembolism included superior vena cava syndrome and catheter dysfunction. In one patient, severe and life-threatening pulmonary embolism occurred. In comparison with patients without venous thromboembolism, venous thromboembolic events were associated with lower body weight (p = 0.03) and longer durations of continuous renal replacement therapy (p < 0.01), mechanical ventilation (p = 0.03), and PICU stay (p < 0.01). Five out of six venous thromboembolisms appeared in neonates.

CONCLUSIONS

Catheter-related venous thromboembolism is a clinically relevant complication of pediatric continuous renal replacement therapy, with a prevalence of 5.7% in our cohort. Clinicians involved in pediatric continuous renal replacement therapy need to be vigilant for symptoms of venous thromboembolisms and initiate appropriate treatment as soon as possible.

Fed-batch production assessment of a tetravalent bispecific antibody: A case study on piggyBac stably transfected HEK293 cells

The transition from preclinical biological drug development into clinical trials requires an efficient upscaling process. In this context, bispecific antibody drugs are particularly challenging due to their propensity to form aggregates and generally produce low titers. Here, the upscaling process for a tetravalent bispecific antibody expressed by a piggyBac transposon-mediated stable HEK293 cell pool has been evaluated. The project was performed as a case study at Testa Center, a non-GMP facility for scale-up testing of biologics in Sweden, and encompassed media adaptation strategies, fed-batch optimization and a novel antibody purification technology. The cell pool was adapted to different culture media for evaluation in terms of cell viability and titers compared to its original Expi293 Expression Medium. These parameters were assessed in both sequential stepwise adaption and direct media exchanges. By this, a more affordable medium was identified that did not require stepwise adaptation and with similar titers and viability as in the Expi293 Expression Medium. Fed-batch optimizations resulted in culture densities reaching up to 20 × 10⁶ viable cells/mL with over 90 % viability 12 days post-inoculum, and antibody titers three times higher than corresponding batch cultures. By implementing a novel high-speed protein A fiber technology (Fibro PrismA) with a capture residence time of only 7.5 s, 8 L of supernatant could be purified in 4.5 h without compromising the purity, structural integrity and function of the bispecific antibody. Results from this study related to medium adaptation and design of fed-batch protocols will be highly beneficial during the forthcoming scale-up of this therapeutic antibody.

[Transfusions in pediatric care - common situations]

Transfusions should be given for medical indications and based on the clinical context for the individual patient. Clinicians should follow the most current existing clinical guidelines. The neonatal hemostatic system differs significantly from that of children and adults. Still, healthy neonates have a balanced hemostatic system. Since the level of hemoglobin is critical to tissue oxygenation, it is important in the rapidly developing neonate. For preterm neonates, different red blood cell transfusion thresholds should be used based on postnatal age and illness severity. Most hemodynamically stable pediatric intensive care patients with a hemoglobin >70 g/L do not require transfusion. Pediatric massive transfusion protocols should exist in pediatric hospitals. At Karolinska University Hospital, red blood cells, fresh frozen plasma and platelets are transfused in a ratio of 20:20:10 mL/kg to children <50 kg. In liver disease, transfusions can lead to increased bleeding.

Turbulence in a small boreal lake: Consequences for air-water gas exchange

The hydrodynamics within small boreal lakes have rarely been studied, yet knowing whether turbulence at the air-water interface and in the water column scales with metrics developed elsewhere is essential for computing metabolism and fluxes of climate-forcing trace gases. We instrumented a humic, 4.7 ha, boreal lake with two meteorological stations, three thermistor arrays, an infrared (IR) camera to quantify surface divergence, obtained turbulence as dissipation rate of turbulent kinetic energy (ε) using an acoustic Doppler velocimeter and a temperature-gradient microstructure profiler, and conducted chamber measurements for short periods to obtain fluxes and gas transfer velocities (k). Near-surface ε varied from 10-8 to 10-6 m2 s-3 for the 0-4 m s-1 winds and followed predictions from Monin-Obukhov similarity theory. The coefficient of eddy diffusivity in the mixed layer was up to 10-3 m2 s-1 on the windiest afternoons, an order of magnitude less other afternoons, and near molecular at deeper depths. The upper thermocline upwelled when Lake numbers (L N ) dropped below four facilitating vertical and horizontal exchange. k computed from a surface renewal model using ε agreed with values from chambers and surface divergence and increased linearly with wind speed. Diurnal thermoclines formed on sunny days when winds were < 3 m s-1, a condition that can lead to elevated near-surface ε and k. Results extend scaling approaches developed in the laboratory and for larger water bodies, illustrate turbulence and k are greater than expected in small wind-sheltered lakes, and provide new equations to quantify fluxes.

Public support for healthcare-mediated disclosure of hereditary cancer risk information: Results from a population-based survey in Sweden

Background

Targeted surveillance of at-risk individuals in families with increased risk of hereditary cancer is an effective prevention strategy if relatives are identified, informed and enrolled in screening programs. Despite the potential benefits, many eligible at-risk relatives remain uninformed of their cancer risk. This study describes the general public's opinion on disclosure of hereditary colorectal cancer (CRC) risk information, as well as preferences on the source and the mode of information.

Methods

A random sample of the general public was assessed through a Swedish citizen web-panel. Respondents were presented with scenarios of being an at-risk relative in a family that had an estimated increased hereditary risk of CRC; either 10% (moderate) or 70% (high) lifetime risk. A colonoscopy was presented as a preventive measure. Results were analysed to identify significant differences between groups using the Pearson's chi-square (χ²) test.

Results

Of 1800 invited participants, 977 completed the survey (54%). In the moderate and high-risk scenarios, 89.2 and 90.6% respectively, would like to receive information about a potential hereditary risk of CRC (χ2, p = .755). The desire to be informed was higher among women (91.5%) than men (87.0%, χ2, p = .044). No significant differences were found when comparing different age groups, educational levels, place of residence and having children or not. The preferred source of risk information was a healthcare professional in both moderate and high-risk scenarios (80.1 and 75.5%). However, 18.1 and 20.1% respectively would prefer to be informed by a family member. Assuming that healthcare professionals disclosed the information, the favoured mode of information was letter and phone (38.4 and 33.2%).

Conclusions

In this study a majority of respondents wanted to be informed about a potential hereditary risk of CRC and preferred healthcare professionals to communicate this information. The two presented levels of CRC lifetime risk did not significantly affect the interest in being informed. Our data offer insights into the needs and preferences of the Swedish population, providing a rationale for developing complementary healthcare-assisted communication pathways to realise the full potential of targeted prevention of hereditary CRC.

Fluid balance after continuous renal replacement therapy initiation and outcome in paediatric multiple organ failure

BACKGROUND

Patients with multiple organ failure (MOF) often receive large amounts of resuscitation fluid, making them at high risk of fluid overload (FO). Our main objective was to investigate if the ability to achieve a negative fluid balance during the first 3 continuous renal replacement therapy (CRRT) days was associated with mortality in children with MOF.

METHODS

Retrospective cohort study in a tertiary multidisciplinary academic paediatric hospital. The study included 63 patients (age 0-18 years) with 3 or more failing organs receiving CRRT due to acute kidney injury and/or fluid overload.

RESULTS

The median age was 4 months, and PICU mortality was 29%. Survivors had significantly lower degree of FO at CRRT initiation, (median 15% (Interquartile range 9-22)) than non-survivors (24% (17%-37%), P = 0.002). On PICU admission, PIM-3 score was significantly higher in non-survivors (P = 0.01), but at CRRT initiation there was no difference in PELOD-2 score (P = 0.98). Mortality in patients achieving a cumulative net negative fluid balance during the first 3 days after CRRT initiation was 12%, compared to 86% in those not achieving this (P < 0.0001). In multivariate analysis, the inability to achieve a net negative fluid balance during 3 days after CRRT initiation (P < 0.0001) and FO >20% at CRRT initiation (P = 0.0019) remained associated with mortality.

CONCLUSION

Our results suggest that early fluid removal is associated with improved patient outcome in critically ill children receiving CRRT, and that prompt measures should be taken to prevent fluid overload in critical illness. These results need to be verified in further, prospective studies.

Modeling vitamin B1 transfer to consumers in the aquatic food web

Vitamin B1 is an essential exogenous micronutrient for animals. Mass death and reproductive failure in top aquatic consumers caused by vitamin B1 deficiency is an emerging conservation issue in Northern hemisphere aquatic ecosystems. We present for the first time a model that identifies conditions responsible for the constrained flow of vitamin B1 from unicellular organisms to planktivorous fishes. The flow of vitamin B1 through the food web is constrained under anthropogenic pressures of increased nutrient input and, driven by climatic change, increased light attenuation by dissolved substances transported to marine coastal systems. Fishing pressure on piscivorous fish, through increased abundance of planktivorous fish that overexploit mesozooplankton, may further constrain vitamin B1 flow from producers to consumers. We also found that key ecological contributors to the constrained flow of vitamin B1 are a low mesozooplankton biomass, picoalgae prevailing among primary producers and low fluctuations of population numbers of planktonic organisms.

Source apportionment of circum-Arctic atmospheric black carbon from isotopes and modeling

Black carbon (BC) contributes to Arctic climate warming, yet source attributions are inaccurate due to lacking observational constraints and uncertainties in emission inventories. Year-round, isotope-constrained observations reveal strong seasonal variations in BC sources with a consistent and synchronous pattern at all Arctic sites. These sources were dominated by emissions from fossil fuel combustion in the winter and by biomass burning in the summer. The annual mean source of BC to the circum-Arctic was 39 ± 10% from biomass burning. Comparison of transport-model predictions with the observations showed good agreement for BC concentrations, with larger discrepancies for (fossil/biomass burning) sources. The accuracy of simulated BC concentration, but not of origin, points to misallocations of emissions in the emission inventories. The consistency in seasonal source contributions of BC throughout the Arctic provides strong justification for targeted emission reductions to limit the impact of BC on climate warming in the Arctic and beyond.

ERα expression in T lymphocytes is dispensable for estrogenic effects in bone

Estrogen treatment has positive effects on the skeleton, and we have shown that estrogen receptor alpha (ERα) expression in cells of hematopoietic origin contributes to a normal estrogen treatment response in bone tissue. T lymphocytes are implicated in the estrogenic regulation of bone mass, but it is not known whether T lymphocytes are direct estrogen target cells. Therefore, the aim of this study was to determine the importance of ERα expression in T lymphocytes for the estrogenic regulation of the skeleton using female mice lacking ERα expression specifically in T lymphocytes (Lck-ERα^-/-) and ERα^flox/flox littermate (control) mice. Deletion of ERα expression in T lymphocytes did not affect bone mineral density (BMD) in sham-operated Lck-ERα^-/- compared to control mice, and ovariectomy (ovx) resulted in a similar decrease in BMD in control and Lck-ERα^-/- mice compared to sham-operated mice. Furthermore, estrogen treatment of ovx Lck-ERα^-/- led to an increased BMD that was indistinguishable from the increase seen after estrogen treatment of ovx control mice. Detailed analysis of both the appendicular (femur) and axial (vertebrae) skeleton showed that both trabecular and cortical bone parameters responded to a similar extent regardless of the presence of ERα in T lymphocytes. In conclusion, ERα expression in T lymphocytes is dispensable for normal estrogenic regulation of bone mass in female mice.

Interleukin 4 induces apoptosis of acute myeloid leukemia cells in a Stat6-dependent manner

Cytokines provide signals that regulate immature normal and acute myeloid leukemia (AML) cells in the bone marrow microenvironment. We here identify interleukin 4 (IL4) as a selective inhibitor of AML cell growth and survival in a cytokine screen using fluorescently labeled AML cells. RNA-sequencing of the AML cells revealed an IL4-induced upregulation of Stat6 target genes and enrichment of apoptosis-related gene expression signatures. Consistent with these findings, we found that IL4 stimulation of AML cells induced Stat6 phosphorylation and that disruption of Stat6 using CRISPR/Cas9-genetic engineering rendered cells partially resistant to IL4-induced apoptosis. To evaluate whether IL4 inhibits AML cells in vivo, we expressed IL4 ectopically in AML cells transplanted into mice and also injected IL4 into leukemic mice; both strategies resulted in the suppression of the leukemia cell burden and increased survival. Notably, IL4 exposure caused reduced growth and survival of primary AML CD34⁺CD38^- patient cells from several genetic subtypes of AML, whereas normal stem and progenitor cells were less affected. The IL4-induced apoptosis of AML cells was linked to Caspase-3 activation. Our results demonstrate that IL4 selectively induces apoptosis of AML cells in a Stat6-dependent manner-findings that may translate into new therapeutic opportunities in AML.

Using accelerometry to quantify prey attack and handling behaviours in piscivorous pike Esox lucius

Accelerometer technology was used to evaluate behaviours in the teleost ambush predator pike Esox lucius foraging on crucian carp Carassius carassius. Automated rule-based estimates of prey-size determined handling time were obtained and are compared with video-recorded behaviours. Solutions to tag attachment and the limitations imposed by battery-time and data-logging capacities are evaluated.

Allochthonous matter: an important factor shaping the phytoplankton community in the Baltic Sea

It is well-known that nutrients shape phytoplankton communities in marine systems, but in coastal waters allochthonous dissolved organic matter (ADOM) may also be of central importance. We studied how humic substances (proxy of ADOM) and other variables influenced the nutritional strategies, size structure and pigment content of the phytoplankton community along a south-north gradient in the Baltic Sea. During the summer, the proportion of mixotrophs increased gradually from the phosphorus-rich south to the ADOM-rich north, probably due to ADOM-fueled microbes. The opposite trend was observed for autotrophs. The chlorophyll a (Chl a): carbon (C) ratio increased while the levels of photoprotective pigments decreased from south to north, indicating adaptation to the darker humic-rich water in the north. Picocyanobacteria dominated in phosphorus-rich areas while nanoplankton increased in ADOM-rich areas. During the winter-spring the phytoplankton biomass and concentrations of photoprotective pigments were low, and no trends with respect to autotrophs and mixotrophs were observed. Microplankton was the dominant size group in the entire study area. We conclude that changes in the size structure of the phytoplankton community, the Chl a:C ratio and the concentrations of photoprotective pigments are indicative of changes in ADOM, a factor of particular importance in a changing climate.

The sources of atmospheric black carbon at a European gateway to the Arctic

Black carbon (BC) aerosols from incomplete combustion of biomass and fossil fuel contribute to Arctic climate warming. Models-seeking to advise mitigation policy-are challenged in reproducing observations of seasonally varying BC concentrations in the Arctic air. Here we compare year-round observations of BC and its δ(13)C/Δ(14)C-diagnosed sources in Arctic Scandinavia, with tailored simulations from an atmospheric transport model. The model predictions for this European gateway to the Arctic are greatly improved when the emission inventory of anthropogenic sources is amended by satellite-derived estimates of BC emissions from fires. Both BC concentrations (R(2)=0.89, P<0.05) and source contributions (R(2)=0.77, P<0.05) are accurately mimicked and linked to predominantly European emissions. This improved model skill allows for more accurate assessment of sources and effects of BC in the Arctic, and a more credible scientific underpinning of policy efforts aimed at efficiently reducing BC emissions reaching the European Arctic.

Structural circular birefringence and dichroism quantified by differential decomposition of spectroscopic transmission Mueller matrices from Cetonia aurata

Transmission Mueller-matrix spectroscopic ellipsometry is applied to the cuticle of the beetle Cetonia aurata in the spectral range 300-1000 nm. The cuticle is optically reciprocal and exhibits circular Bragg filter features for green light. By using differential decomposition of the Mueller matrix, the circular and linear birefringence as well as dichroism of the beetle cuticle are quantified. A maximum value of structural optical activity of 560°/mm is found.

Allochthonous Carbon--a Major Driver of Bacterioplankton Production in the Subarctic Northern Baltic Sea

Heterotrophic bacteria are, in many aquatic systems, reliant on autochthonous organic carbon as their energy source. One exception is low-productive humic lakes, where allochthonous dissolved organic matter (ADOM) is the major driver. We hypothesized that bacterial production (BP) is similarly regulated in subarctic estuaries that receive large amounts of riverine material. BP and potential explanatory factors were measured during May-August 2011 in the subarctic Råne Estuary, northern Sweden. The highest BP was observed in spring, concomitant with the spring river-flush and the lowest rates occurred during summer when primary production (PP) peaked. PLS correlations showed that ∼60% of the BP variation was explained by different ADOM components, measured as humic substances, dissolved organic carbon (DOC) and coloured dissolved organic matter (CDOM). On average, BP was threefold higher than PP. The bioavailability of allochthonous dissolved organic carbon (ADOC) exhibited large spatial and temporal variation; however, the average value was low, ∼2%. Bioassay analysis showed that BP in the near-shore area was potentially carbon limited early in the season, while BP at seaward stations was more commonly limited by nitrogen-phosphorus. Nevertheless, the bioassay indicated that ADOC could contribute significantly to the in situ BP, ∼60%. We conclude that ADOM is a regulator of BP in the studied estuary. Thus, projected climate-induced increases in river discharge suggest that BP will increase in subarctic coastal areas during the coming century.

Effects of predicted climatic changes on distribution of organic contaminants in brackish water mesocosms

Predicted consequences of future climate change in the northern Baltic Sea include increases in sea surface temperatures and terrestrial dissolved organic carbon (DOC) runoff. These changes are expected to alter environmental distribution of anthropogenic organic contaminants (OCs). To assess likely shifts in their distributions, outdoor mesocosms were employed to mimic pelagic ecosystems at two temperatures and two DOC concentrations, current: 15°C and 4 mg DOCL(-1) and, within ranges of predicted increases, 18°C and 6 mg DOCL(-1), respectively. Selected organic contaminants were added to the mesocosms to monitor changes in their distribution induced by the treatments. OC partitioning to particulate matter and sedimentation were enhanced at the higher DOC concentration, at both temperatures, while higher losses and lower partitioning of OCs to DOC were observed at the higher temperature. No combined effects of higher temperature and DOC on partitioning were observed, possibly because of the balancing nature of these processes. Therefore, changes in OCs' fates may largely depend on whether they are most sensitive to temperature or DOC concentration rises. Bromoanilines, phenanthrene, biphenyl and naphthalene were sensitive to the rise in DOC concentration, whereas organophosphates, chlorobenzenes (PCBz) and polychlorinated biphenyls (PCBs) were more sensitive to temperature. Mitotane and diflufenican were sensitive to both temperature and DOC concentration rises individually, but not in combination.

Circulating prolactin and breast cancer risk among pre- and postmenopausal women in the EPIC cohort

BACKGROUND

Experimental and epidemiological evidence suggests that prolactin might play a role in the etiology of breast cancer. We analyzed the relationship of prediagnostic circulating prolactin levels with the risk of breast cancer by menopausal status, use of postmenopausal hormone replacement therapy (HRT) at blood donation, and by estrogen and progesterone receptor status of the breast tumors.

PATIENTS AND METHODS

Conditional logistic regression was used to analyze the data from a case-control study nested within the prospective European EPIC cohort, including 2250 invasive breast cancer and their matched control subjects.

RESULTS

Statistically significant heterogeneity in the association of prolactin levels with breast cancer risk between women who were either pre- or postmenopausal at the time of blood donation was observed (Phet = 0.04). Higher serum levels of prolactin were associated with significant increase in the risk of breast cancer among postmenopausal women [odds ratio (OR)Q4-Q1 = 1.29 (95% confidence interval, CI, 1.05-1.58), Ptrend = 0.09]; however, this increase in risk seemed to be confined to women who used postmenopausal HRT at blood donation [ORQ4-Q1 = 1.45 (95% CI 1.08-1.95), Ptrend = 0.01], whereas no statistically significant association was found for the non-users of HRT [ORQ4-Q1 = 1.11 (95%CI 0.83-1.49), Ptrend = 0.80] (Phet = 0.08). Among premenopausal women, a statistically non-significant inverse association was observed [ORQ4-Q1 = 0.70 (95% CI 0.48-1.03), Ptrend = 0.16]. There was no heterogeneity in the prolactin-breast cancer association by hormone receptor status of the tumor.

CONCLUSION

Our study indicates that higher circulating levels of prolactin among the postmenopausal HRT users at baseline may be associated with increased breast cancer risk.

Francisella tularensis subspecies holarctica occurs in Swedish mosquitoes, persists through the developmental stages of laboratory-infected mosquitoes and is transmissible during blood feeding

In Sweden, mosquitoes are considered the major vectors of the bacterium Francisella tularensis subsp. holarctica, which causes tularaemia. The aim of this study was to investigate whether mosquitoes acquire the bacterium as aquatic larvae and transmit the disease as adults. Mosquitoes sampled in a Swedish area where tularaemia is endemic (Örebro) were positive for the presence of F. tularensis deoxyribonucleic acid throughout the summer. Presence of the clinically relevant F. tularensis subsp. holarctica was confirmed in 11 out of the 14 mosquito species sampled. Experiments performed using laboratory-reared Aedes aegypti confirmed that F. tularensis subsp. holarctica was transstadially maintained from orally infected larvae to adult mosquitoes and that 25% of the adults exposed as larvae were positive for the presence of F. tularensis-specific sequences for at least 2 weeks. In addition, we found that F. tularensis subsp. holarctica was transmitted to 58% of the adult mosquitoes feeding on diseased mice. In a small-scale in vivo transmission experiment with F. tularensis subsp. holarctica-positive adult mosquitoes and susceptible mice, none of the animals developed tularaemia. However, we confirmed that there was transmission of the bacterium to blood vials by mosquitoes that had been exposed to the bacterium in the larval stage. Taken together, these results provide evidence that mosquitoes play a role in disease transmission in part of Sweden where tularaemia recurs.

Impacts of elevated terrestrial nutrient loads and temperature on pelagic food-web efficiency and fish production

Both temperature and terrestrial organic matter have strong impacts on aquatic food-web dynamics and production. Temperature affects vital rates of all organisms, and terrestrial organic matter can act both as an energy source for lower trophic levels, while simultaneously reducing light availability for autotrophic production. As climate change predictions for the Baltic Sea and elsewhere suggest increases in both terrestrial matter runoff and increases in temperature, we studied the effects on pelagic food-web dynamics and food-web efficiency in a plausible future scenario with respect to these abiotic variables in a large-scale mesocosm experiment. Total basal (phytoplankton plus bacterial) production was slightly reduced when only increasing temperatures, but was otherwise similar across all other treatments. Separate increases in nutrient loads and temperature decreased the ratio of autotrophic:heterotrophic production, but the combined treatment of elevated temperature and terrestrial nutrient loads increased both fish production and food-web efficiency. CDOM: Chl a ratios strongly indicated that terrestrial and not autotrophic carbon was the main energy source in these food webs and our results also showed that zooplankton biomass was positively correlated with increased bacterial production. Concomitantly, biomass of the dominant calanoid copepod Acartia sp. increased as an effect of increased temperature. As the combined effects of increased temperature and terrestrial organic nutrient loads were required to increase zooplankton abundance and fish production, conclusions about effects of climate change on food-web dynamics and fish production must be based on realistic combinations of several abiotic factors. Moreover, our results question established notions on the net inefficiency of heterotrophic carbon transfer to the top of the food web.

Fast determination of antibiotics in whole blood

There is a need for analytical methods capable of monitoring blood antibiotic levels in real time. Here we present a method for quantifying antibiotic levels in whole blood that does not require any sample pretreatment. The tests employ the enzyme penicillinase to assay for penicillin G, penicillin V and ampicillin using a flow-injected biosensor, the Enzyme Thermistor. Optimal flow rates, sample volumes and pH were determined to be 0.5 mL/min, 100 μL and 7.0, respectively. Analysis of the antibiotics diluted in buffer gave a linear range of 0.17-5.0 mM. Calibration curves prepared using blood spiked with the antibiotics gave a linear range of 0.17-2.0 mM. Linear regression values for all of the calibration curves were 0.998 or higher. Assay cycle time was 5 min. The relative standard deviation value for 100 determinations of a mock blood sample spiked with penicillin G was 6.71%. Despite the elimination of sample pretreatment, no detectable clogging or signal drift was observed. The assay provides a fast, simple, reliable analytical method for determining antibiotic concentrations in blood without the need for any sample pretreatment. This is an important first step towards developing a device capable of real-time monitoring of antibiotic levels in whole blood. The technology has the potential to significantly improve the outcomes of patients undergoing critical care.