Randomised, blinded, cross-over evaluation of the palatability of and preference for different potassium binders in participants with chronic hyperkalaemia in the USA, Canada and Europe: the APPETIZE study

OBJECTIVES

Traditional potassium (K+) binders for treating hyperkalaemia are unpalatable and poorly tolerated. Newer K+ binders are reportedly better tolerated; however, no published data describe their palatability, a determinant of long-term adherence. This study evaluated the palatability of and preference for three K+ binders: sodium and calcium polystyrene sulfonate (S/CPS), sodium zirconium cyclosilicate (SZC) and calcium patiromer sorbitex (patiromer).

DESIGN

Phase 4, randomised, participant-blinded, cross-over study. Participants were randomised to one of six taste sequences and, using a 'sip and spit' approach, tasted each K+ binder before completing a survey.

SETTING

17 centres across the USA, Canada and European Union.

PARTICIPANTS

144 participants with chronic kidney disease, hyperkalaemia and no recent use of K+ binders.

MAIN OUTCOME MEASURES

For the primary (USA) and key secondary (Canada and European Union) endpoints, participants rated palatability attributes (taste, texture, smell and mouthfeel) and willingness to take each K+ binder on a scale of 0-10 (rational evaluation). Feelings about each attribute, and the idea of taking the product once daily, were evaluated using a non-verbal, visual measure of emotional response. Finally, participants ranked the K+ binders according to palatability.

RESULTS

In each region, SZC and patiromer outperformed S/CPS on overall palatability (a composite of taste, texture, smell and mouthfeel), based on rational evaluation and emotional response. Taking the product once daily was more appealing for SZC and patiromer, creating greater receptivity than the idea of taking S/CPS. The emotional response to mouthfeel had the strongest influence on feelings about taking each product. In each region, a numerically greater proportion of participants ranked SZC as the most preferred K+ binder versus patiromer or S/CPS.

CONCLUSIONS

Preference for more palatable K+ binders such as SZC and patiromer may provide an opportunity to improve adherence to long-term treatment of hyperkalaemia.

TRIAL REGISTRATION NUMBER

NCT04566653.

Decisional needs in people with kidney failure, their relatives and health professionals about end-of-life care options: A qualitative interview study

AIM

To investigate the decisional needs in Denmark of people with kidney failure, relatives, and health professionals when planning end-of-life care.

DESIGN

A qualitative interview study.

METHODS

Individual semi-structured interviews were carried out with people with kidney failure, relatives and health professionals from November 2021 to June 2022. Malterud's systematic text condensation was used to analyse transcripts.

RESULTS

A total of 13 patients, 10 relatives, and 12 health professionals were interviewed. Overall, four concepts were agreed on: (1) Talking about end of life is difficult, (2) Patients and relatives need more knowledge and information, (3) Health professionals need more tools and training, and (4) Experiencing busyness as a barrier to conversations about end of life.

CONCLUSION

People with kidney failure, relatives, and health professionals shared certain decisional needs while also having some different decisional needs about end-of-life care. To meet these various needs, end-of-life conversations should be systematic and organized according to the patients' needs and wishes.

IMPACT

Non-systematic end-of-life care decision-making processes limit patients' involvement. Patients and relatives need more knowledge about end-of-life care, and health professionals need more competences and time to discuss decisional needs. A shared decision-making intervention for people with kidney failure when making end-of-life care decisions will be developed.

REPORTING METHOD

This empirical qualitative research is reported according to the Consolidated Criteria for Reporting Qualitative Research (COREQ) checklist.

PATIENT OR PUBLIC CONTRIBUTION

Patients, relatives, and health professionals have been involved throughout the research process as part of the research team and advisory board. The patients are people with kidney failure and the relatives are relatives of a person with kidney failure. For this study, the advisory board has particularly contributed to the validation of the invitation letter for participation, the interview guides and the preparation of the manuscript.

Recommendations for successful involvement of patient partners in complex intervention research: a collaborative learning process

BACKGROUND

Patient and public involvement in health-related research is a new discipline in Denmark. In 2021, a national conference titled 'Patient and Public Involvement in Complex Intervention Research' provided a forum for discussion between patient partners, researchers and clinicians on involving patients as partners in complex intervention research.

METHODS

We aimed to describe specific challenges to and initiatives for patient partner involvement in order to develop recommendations for creating successful partnerships in complex intervention research. Through a collaborative learning process, 140 researchers identified the most important challenges for them in patient partner involvement and potential initiatives to improve such involvement. At a subsequent workshop, four patient partners identified the challenges and initiatives from their perspective as patient partners. They also gave feedback on the challenges and initiatives suggested by the researchers and helped shape three recommendations for practice. Three of the patient partners were involved in writing this paper.

RESULTS

The five most important challenges identified by researchers were time, recruitment, ethics, power and inequality. Between four and seven initiatives to overcome these challenges were suggested. The three most important challenges identified by patient partners were communication, when you get information that is hard to handle and recruitment. They suggested three to four initiatives for improvement. Patient partners confirmed the importance of all the researcher identified challenges when presented with them, they also provided additional comments on the researchers' initiatives. This led to the formation of recommendations for involving patient partners.

CONCLUSIONS

A collaborative learning process was shown to be a suitable method for patient partner involvement. Consistency was seen between the challenges and initiatives identified by researchers and patient partners. Based on these observations, three recommendations were developed: (1) create specific programmes that aim to involve all kind of patients (including but limited to vulnerable patients) as patient partners, (2) produce ethical guidelines for the involvement of patient partners, and (3) develop a national strategy for patient partner involvement. To build on these recommendations, a joint workshop with both researchers and patient partners is needed.

Patient involvement interventions for patients with kidney failure making end-of-life care decisions: a scoping review

OBJECTIVE

The objective of this review was to investigate and map empirical evidence of patient involvement interventions to support patients with kidney failure making end-of-life care decisions in kidney services.

INTRODUCTION

Clinical guidance integrating end-of-life care within kidney failure management pathways varies. Advance care planning interventions aimed at involving patients with kidney failure in their end-of-life care planning are established in some countries. However, there is limited evidence of the other types of patient involvement interventions integrated within services to support patients with kidney failure in making decisions about their end-of-life care.

INCLUSION CRITERIA

This scoping review included studies exploring patient involvement interventions evaluated for patients with kidney failure considering end-of-life care, their relatives, and/or health professionals in kidney services. Studies of children under the age of 18 years were excluded.

METHODS

The review was informed by JBI methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Review guidelines. MEDLINE, Scopus, Embase, and CINAHL were searched for full-text studies in English, Danish, German, Norwegian, or Swedish. Two independent reviewers assessed the literature against the inclusion criteria. A relational analysis framework was used to synthesize the data extracted from the included studies, and to investigate and map different patient involvement interventions.

RESULTS

The search identified 1628 articles, of which 33 articles met the inclusion criteria. A total of 23 interventions were described. Interventions targeted patients (n=3); health professionals (n=8); patients and health professionals (n=5); and patients, relatives, and health professionals (n=7). Intervention components included patient resources (eg, information, patient decision aids), consultation resources (eg, advance care planning, shared decision-making), and practitioner resources (eg, communication training). Patient involvement interventions were delivered within hospital-based kidney services.

CONCLUSIONS

The review identified several ways to support patients with kidney failure to be involved in end-of-life care decisions. Future interventions may benefit from adopting a complex intervention framework to engage multiple stakeholders in the research and design of an intervention for shared decision-making between patients with kidney failure, their relatives, and health professionals about integrating end-of-life care options into their kidney disease management pathway.

The value of partnership in patient-driven as well as in researcher-driven projects

Patient involvement in health research is rarely driven solely by patients, who could be considered to have the highest degree of investment in such research. In the Kidney Connect project, the patients have been the driving force. This commentary considers the following questions: How did we, as patients, lead the work as the driving force in the project? What went well and what did not go so well from our perspective? How did the project compare with work driven by researchers? We argue that projects driven solely by either patients or researchers each have their own limitations. Projects driven solely by patients have some limitations in their robustness, rigour, and likelihood of publication. Nevertheless, a project driven solely by patients has been able to produce findings that are broadly comparable to a project driven solely by researchers that employed methods ensuring robustness and rigour. We suggest collaboration between patients and researchers also for projects driven by patients.

Coordinating efforts to optimize next-generation kidney replacement therapies: the European Kidney Health Alliance Work Group “Breakthrough Innovation”

Chronic kidney disease is one of the fastest growing health problems, set to become the fifth global death cause by 2040. Factors contributing to this fast growth include increased survival from other diseases (cancer, cardiovascular disease, diabetes, etc.), population aging, lack of early CKD diagnosis tools, insufficient CKD awareness within healthcare systems, limited therapeutic armamentarium to prevent CKD progression, and limitations of currently available kidney replacement therapies (KRTs). The European Kidney Health Alliance (EKHA) and the American Association of Kidney Patients (AAKP) joined forces within the Decade of the KidneyTM framework to address these issues. We report on the rationale and vision of the EKHA Work Group ‘Breakthrough Innovation’ which aims to disrupt the existing innovation paradox on KRT. We discuss how the concepts of international technological roadmapping and coopetition may leverage breakthrough KRT technologies, and present a map of the kidney innovation playing field, driven by patient advocacy groups.

Shared decision-making and planning end-of-life care for patients with end-stage kidney disease: a protocol for developing and testing a complex intervention

Background

Internationally, it has been stressed that advance care planning integrated within kidney services can lead to more patients being involved in decisions for end-of-life care. In Denmark, there is no systematic approach to advance care planning and end-of-life care interventions within kidney services. A shared decision-making intervention for planning end-of-life care may support more effective treatment management between patients with end-stage kidney disease, their relatives and the health professionals. The purpose of this research is to find evidence to design a shared decision-making intervention and test its acceptability to patients with end-stage kidney disease, their relatives, and health professionals in Danish kidney services.

Methods

This research project will be conducted from November 2020 to November 2023 and is structured according to the UK Medical Research Council framework for complex intervention design and evaluation research. The development phase research includes mixed method surveys. First, a systematic literature review synthesising primary empirical evidence of patient-involvement interventions for patients with end-stage kidney disease making end-of-life care decisions will be conducted. Second, interview methods will be carried out with patients with end-stage kidney disease, relatives, and health professionals to identify experiences of involvement in decision-making and decisional needs when planning end-of-life care. Findings will inform the co-design of the shared decision-making intervention using an iterative process with our multiple-stakeholder steering committee. A pilot test across five kidney units assessing if the shared decision-making intervention is acceptable and feasible to patients, relatives, and health professionals providing services to support delivery of care in kidney services.

Discussion

This research will provide evidence informing the content and design of a shared decision-making intervention supporting patient-professional planning of end-of-life care for patients with end-stage kidney disease, and assessing its acceptability and feasibility when integrated within Danish kidney units. This research is the first step to innovating the involvement of patients in end-of-life care planning with kidney professionals.

Mapping the empirical evidence on patient involvement interventions in patients with end-stage kidney disease making end-of-life care decisions: a scoping review protocol

OBJECTIVE

The objective of this scoping review is to investigate and map existing empirical evidence on patient involvement interventions helping patients with end-stage kidney disease to make end-of-life care decisions about kidney services.

INTRODUCTION

Patients with end-stage kidney disease have a high disease burden and mortality rate. Despite this, kidney services differ in how they offer and integrate end-of-life care, if it is offered at all. Some countries have established advance care planning protocols to encourage patient involvement when offering end-of-life care options as part of end-stage kidney disease care. However, there is a limited understanding of the components of patient involvement interventions designed to support patients with end-stage kidney disease making decisions about end-of-life care.

INCLUSION CRITERIA

The review will consider studies on patient involvement interventions concerning end-of-life care decisions for patients with end-stage kidney disease. A broad definition of patient involvement interventions will be used. Studies on interventions that do not involve patients or relatives will be excluded. The review will focus on interventions applied to kidney health care and other services, such as community-based health care.

METHODS

MEDLINE, Embase, Scopus, and CINAHL will be searched. The literature will be screened for inclusion by two independent reviewers. Data synthesis will be conducted through relational analysis investigating patient involvement interventions and relevant information in line with the review objective and questions. Data will be extracted and listed in the data extraction instruments, accompanied by a narrative summary describing how the results relate to the review objective.

Father of Artificial Organs - The story of medical pioneer Willem J. Kolff (1911-2009)

This biography of serial inventor and medical doctor Willem J. ("Pim") Kolff is written by scientific/historical journalist Herman Broers. The book provides an objective and multi-perspective account of the life and work of Dr. Kolff, who put an undisputed mark on the history of organ-replacement devices by secretly inventing the first clinically functioning hemodialysis machine (in a Nazi-occupied Holland) and later in the United States leading the team that realized the first implantable fully artificial heart. Besides offering a solid historical account, the book also describes the present revival of innovation in the artificial kidney field and contains valuable lessons for a broad variety of readers. Suitable for an audience ranging from medical professionals interested in technology & technologists interested in medicine, to patients & their families, as well as policy makers & research funding parties. The review of this scientific/historic book was composed using the recommendations of Gupta for book reviews of scientific and technical books. Additionally, the reviewer team, composed of a biomedical engineer, a dialysis patient, and a nephrologist, tried to distil some lessons that may be learned from the book.

Involvement of patients with chronic kidney disease in research: A case study

BACKGROUND

Knowledge about best practices of patient involvement in research among patients with chronic kidney disease is sparse, with little information about barriers to and facilitators of this process. The purpose of this study is to evaluate the process and outcomes of patient involvement in a particular chronic kidney disease research project.

OBJECTIVES

To describe how patients with chronic kidney disease were involved in the research; to explain what occurred when patients with chronic kidney disease were involved; to identify facilitators of and barriers to patient involvement in research.

PARTICIPANTS

Two patients with chronic kidney disease who have both been involved in a previous research project.

MEASUREMENTS

A retrospective embedded case study of patient involvement in research with the shared decision-making and dialysis choice project inspired by Yin (2012, Case Study Methods), using document analysis and semistructured individual interviews. Data were analysed with specific research questions in mind.

RESULTS

Two patients participated in four research meetings covering all substudies of a research project and all six phases of the research process. Eight facilitators and barriers were identified.

CONCLUSIONS

Patients with chronic kidney disease were involved in all the six phases of the research process but were more highly involved in some phases than others. Important facilitators of patient involvement in chronic kidney disease research include working as a team, being a part of the process, and being prepared for the work. Important barriers to patient involvement include patient vulnerability and uremic symptoms, both of which must be taken into account.

Four- and six-hour urinary albumin excretion is a valuable alternative to 24-h urinary albumin excretion in male db/db mice

In mouse (Mus musculus) models of diabetic nephropathy (DN), one of the most important read-outs is the 24-h urinary albumin excretion (UAE). The 24-h urine collection is usually performed by single housing mice in metabolic cages on wire mesh without enrichment. This is known to be stressful for the mice. Therefore, it was investigated if shorter urine collections would be sufficient to get reliable assessments of albuminuria. Twenty-one diabetic (C57BLKS-Leprdb/db) and ten non-diabetic mice (C57BLKS-Leprdb/+) were placed in metabolic cages at 15 and 20 weeks of age (WoA) for 24 h. Urine samples were taken at 4, 6, 18 and 24 h and albumin and creatinine concentration were measured. Four- and 6-h UAE was found to correlate significantly with 24-h UAE. Furthermore, a significant correlation was found between 24-h UAE and albumin:creatinine ratio (ACR) in the 4-h sample. However, the strength of the correlation between ACR and 24-h UAE was weaker than between the 4- and 24-h UAE. This suggests that normalising to creatinine may not provide additional value to the 4-h urine collection. In conclusion, the strong correlation between 4- and 6-h UAE and 24-h UAE indicates that the collection period can be considerably reduced. This refinement could reduce stress and increase welfare of the db/db model and potentially be applied to other DN models

Muscle mass and inspired oxygen influence oxygen extraction at maximal exercise: Role of mitochondrial oxygen affinity

AIM

We examined the Fick components together with mitochondrial O₂ affinity (p50_mito ) in defining O₂ extraction and O₂ uptake during exercise with large and small muscle mass during normoxia (NORM) and hyperoxia (HYPER).

METHODS

Seven individuals performed 2 incremental exercise tests to exhaustion on a bicycle ergometer (BIKE) and 2 on a 1-legged knee extension ergometer (KE) in NORM or HYPER. Leg blood flow and VO₂ were determined by thermodilution and the Fick method. Maximal ADP-stimulated mitochondrial respiration (OXPHOS) and p50_mito were measured ex vivo in isolated mitochondria. Mitochondrial excess capacity in the leg was determined from OXPHOS in permeabilized fibres and muscle mass measured with magnetic resonance imaging in relation to peak leg O₂ delivery.

RESULTS

The ex vivo p50_mito increased from 0.06 ± 0.02 to 0.17 ± 0.04 kPa with varying substrate supply and O₂ flux rates from 9.84 ± 2.91 to 16.34 ± 4.07 pmol O₂ ·s^-1 ·μg^-1 respectively. O₂ extraction decreased from 83% in BIKE to 67% in KE as a function of a higher O₂ delivery and lower mitochondrial excess capacity. There was a significant relationship between O₂ extraction and mitochondrial excess capacity and p50_mito that was unrelated to blood flow and mean transit time.

CONCLUSION

O₂ extraction varies with mitochondrial respiration rate, p50_mito and O₂ delivery. Mitochondrial excess capacity maintains a low p50_mito which enhances O₂ diffusion from microvessels to mitochondria during exercise.

Central and peripheral hemodynamics in exercising humans: leg vs arm exercise

In humans, arm exercise is known to elicit larger increases in arterial blood pressure (BP) than leg exercise. However, the precise regulation of regional vascular conductances (VC) for the distribution of cardiac output with exercise intensity remains unknown. Hemodynamic responses were assessed during incremental upright arm cranking (AC) and leg pedalling (LP) to exhaustion (Wmax) in nine males. Systemic VC, peak cardiac output (Qpeak) (indocyanine green) and stroke volume (SV) were 18%, 23%, and 20% lower during AC than LP. The mean BP, the rate-pressure product and the associated myocardial oxygen demand were 22%, 12%, and 14% higher, respectively, during maximal AC than LP. Trunk VC was reduced to similar values at Wmax. At Wmax, muscle mass-normalized VC and fractional O2 extraction were lower in the arm than the leg muscles. However, this was compensated for during AC by raising perfusion pressure to increase O2 delivery, allowing a similar peak VO2 per kg of muscle mass in both extremities. In summary, despite a lower Qpeak during arm cranking the cardiovascular strain is much higher than during leg pedalling. The adjustments of regional conductances during incremental exercise to exhaustion depend mostly on the relative intensity of exercise and are limb-specific.

Mitochondrial coupling and capacity of oxidative phosphorylation in skeletal muscle of Inuit and Caucasians in the arctic winter

During evolution, mitochondrial DNA haplogroups of arctic populations may have been selected for lower coupling of mitochondrial respiration to ATP production in favor of higher heat production. We show that mitochondrial coupling in skeletal muscle of traditional and westernized Inuit habituating northern Greenland is identical to Danes of western Europe haplogroups. Biochemical coupling efficiency was preserved across variations in diet, muscle fiber type, and uncoupling protein-3 content. Mitochondrial phenotype displayed plasticity in relation to lifestyle and environment. Untrained Inuit and Danes had identical capacities to oxidize fat substrate in arm muscle, which increased in Danes during the 42 days of acclimation to exercise, approaching the higher level of the Inuit hunters. A common pattern emerges of mitochondrial acclimatization and evolutionary adaptation in humans at high latitude and high altitude where economy of locomotion may be optimized by preservation of biochemical coupling efficiency at modest mitochondrial density, when submaximum performance is uncoupled from VO2max and maximum capacities of oxidative phosphorylation.

Joint bleeds increase the inhibitor response to human factor VIII in a rat model of severe haemophilia A

INTRODUCTION

The most serious complication in haemophilia A (HA) replacement therapy with coagulation factor VIII (FVIII) is neutralizing antibodies, i.e. inhibitors. It has been hypothesized that danger signals generated during a bleed might have an adjuvant effect on the immune response to FVIII in on-demand treatment, increasing the inhibitor risk.

AIM

To compare the antibody response to treatment with recombinant human FVIII (rhFVIII) in relation to induced knee joint bleeds and treatment without concurrent bleeds in a HA rat model.

METHOD

HA rats were divided into two groups: one group (n = 10) receiving three needle induced knee joint bleeds 14 days apart and a control group (n = 9) receiving three sham procedures. Three hours after each injury/sham 50 IU kg(-1) rhFVIII was administrated intravenously. Subsequently, both groups continued rhFVIII treatment for another 9 weeks. Binding antibodies were analysed using an enzyme-linked immunosorbent assay and neutralizing antibodies using a Bethesda-like assay.

RESULTS

Rats in the knee-bleed group developed a significantly faster inhibitor response and reached significantly higher inhibitor levels. In the knee-bleed group, 80% developed inhibitors vs. 33% in the control group, demonstrating a 2.4 times higher inhibitor risk when treating concurrent with bleeds.

CONCLUSION

FVIII treatment in relation to a bleed potentiates inhibitor development compared to FVIII treatment alone in this HA rat, indicating that bleeding is a potential danger signal. Our results support the theory that FVIII replacement therapy concurrent with a bleeding episode increases the inhibitor risk, which to the best of our knowledge, has not been confirmed in an animal model before.

Antibody response to recombinant human coagulation factor VIII in a new rat model of severe hemophilia A

BACKGROUND

Neutralizing antibodies toward FVIII replacement therapy (inhibitors) are the most serious treatment-related complication in hemophilia A (HA). A rat model of severe HA (F8(-/-) ) has recently been developed, but an immunological characterization is needed to determine the value of using the model for research into inhibitor development.

OBJECTIVES

Characterize the antibody response towards recombinant human coagulation factor VIII (rhFVIII) in the HA rat, following a human prophylactic dosing regimen.

METHODS

Two identical studies were performed, which included a total of 17 homozygous HA rats (F8(-/-) , 0% FVIII activity), 12 heterozygous rats (F8(+/-) ), and 12 wild-type (F8(+/+) ) rats. All rats received intravenous injections of rhFVIII at 50 IU kg(-1) twice weekly for 4 weeks. Predosing blood samples were analyzed for binding and neutralizing anti-rhFVIII antibodies at weeks 1-7.

RESULTS

In both studies, antibodies developed after 4-6 administrations of rhFVIII, and neutralizing antibodies reached levels similar to human patients (range 1-111 BU, median 6.0 BU) at the end of the study. There was no significant difference between the two studies or between genotypes in time to response or levels reached for binding and neutralizing antibodies. Interestingly, early spontaneous bleeds were associated with a faster antibody response.

CONCLUSIONS

Following intravenous administration of human FVIII, according to a clinical prophylaxis regimen, a robust and reproducible antibody response is seen in this HA rat model, suggesting that the model is useful for intervention studies with the aim of suppressing, delaying, or preventing the inhibitor response. Also, bleeds seem to have an adjuvant effect on the immune response.

Human T cells depend on functional calcineurin, tumour necrosis factor-α and CD80/CD86 for expansion and activation in mice

Dysregulated T cells are a hallmark of several autoimmune and inflammatory diseases; thus, models to study human T cells in vivo are advantageous, but limited by lacking insight into human T cell functionality in mice. Using non-obese diabetic (NOD), severe combined immunodeficient (SCID) or recombination activating gene-1 (RAG1)(-/-) and interleukin-2 receptor gamma-chain (IL-2Rγ)(-/-) mice reconstituted with human peripheral blood mononuclear cells (PBMCs), we have studied the mechanisms of human T cell expansion and activation in mice. Injection of human PBMCs into mice caused consistent xeno-engraftment with polyclonal expansion and activation of functional human T cells and production of human cytokines. Human T cell expansion coincided with development of a graft-versus-host disease (GVHD)-like condition observed as weight loss, multi-organ immune infiltration and liver damage. CD8(+) T cells alone were sufficient for expansion and required for disease development; in contrast, CD4(+) T cells alone expanded but did not induce acute disease and, rather, exerted regulatory capacity through CD25(+)CD4(+) T cells. Using various anti-inflammatory compounds, we demonstrated that several T cell-activation pathways controlled T cell expansion and disease development, including calcineurin-, tumour necrosis factor-α and co-stimulatory signalling via the CD80/CD86 pathway, indicating the diverse modes of action used by human T cells during expansion and activation in mice as well as the pharmacological relevance of this model. Overall, these data provide insight into the mechanisms used by human T cells during expansion and activation in mice, and we speculate that PBMC-injected mice may be useful to study intrinsic human T cell functions in vivo and to test T cell-targeting compounds.

Update on acute endovascular and surgical stroke treatment

Emergency stroke care has become a natural part of the emerging discipline of neurocritical care and demands close cooperation between the neurologist and neurointerventionists, neurosurgeons, and anesthesiologists. Endovascular treatment (EVT), including intra-arterial thrombolysis, mechanical thrombectomy and angioplasty/stenting, is under rapid development. Although EVT has yet to be shown in randomized controlled trials to improve clinical outcome compared to intravenous thrombolysis, it is far better in achieving recanalization of occluded large cerebral vessels, which is crucial for rescuing the penumbra. Moreover, decompressive craniectomy is now a well-established treatment option for malignant middle cerebral artery infarction and cerebellar stroke. Using a case-based approach, this article reviews recent achievements in advanced treatment options for patients with acute ischemic stroke.

IL-21: roles in immunopathology and cancer therapy

Cytokines are secreted signalling molecules with decisive effects on haematopoiesis, innate and adaptive immunity, and immunopathology. Interleukin (IL)-21 is a novel cytokine produced by activated CD4(+) T cells and natural killer T (NKT) cells. IL-21 is part of a family of cytokines which include IL-2, -4, -7, -9 and -15 that all share the common IL-2 receptor gamma chain (gamma(c)) in their individual receptor complexes. IL-21 receptor (IL-21R) is widely expressed on both myeloid and lymphoid cell lineages and IL-21 actions include co-stimulation of B cell differentiation and immunoglobulin (Ig) production, co-mitogen of T cells, and stimulation of NK and CD8(+) T cell cytotoxic function. Initially, IL-21 was recognized for its anti-tumour effects in several preclinical tumour models, warranting its currently ongoing clinical development as a cancer immunotherapeutic. More recently, IL-21 has been associated with the development of a panel of autoimmune and inflammatory diseases, where neutralization of IL-21 has been suggested as a potential new therapy. In this review, we will cover the latest discoveries of IL-21 as a cancer therapy and its implications in immunopathologies.

Body dimensions, exercise capacity and physical activity level of adolescent Nandi boys in western Kenya

The aim of this study was to characterize untrained Nandi boys (mean age 16.6 years) from a town (n = 11) and from a rural area (n = 19) in western Kenya (altitude approximately 2000 m.a.s.l.) in regard to their body dimensions, oxygen uptake and physical activity level. The town boys had a mean maximal oxygen uptake (VO(2 max)) of 50 (range: 45-60) mL kg(-1) min(-1), whereas the village boys reached a value of 55 (37-63) mL kg(-1) min(-1) ( p<0.01) in VO(2 max). The running economy, determined as the oxygen cost at a given running speed, was 221 mL kg(-1) km(-1) (597 mL kg(-0.75) km(-1)) for town as well as for village boys. The body mass index (BMI) was very low for town as well as for village boys (18.6 vs 18.4 kg m(-2)). The daily mean time spent working in the field during secondary school and doing sports were significantly higher in village boys compared to town boys (working in the field: 44.2 (0-128) vs 1.3 (0-11) min, p<0.01; sports: 32.0 (11-72) vs 12.8 (0-35) min, p<0.01, respectively). A positive correlation between the daily time spent doing sports and VO(2 max) was found when pooling the data from the town and the village boys (R = 0.55, p<0.01). It is concluded that the body dimensions of adolescent Nandi town and village boys corresponds well with findings in Kenyan elite runners. They are very slender with relatively long legs. In addition, the VO(2 max) of the village boys was higher than that of the town boys, which is probably due to a higher physical activity level of the village boys during secondary school.

Determinants of maximal oxygen uptake in severe acute hypoxia

To unravel the mechanisms by which maximal oxygen uptake (VO2 max) is reduced with severe acute hypoxia in humans, nine Danish lowlanders performed incremental cycle ergometer exercise to exhaustion, while breathing room air (normoxia) or 10.5% O2 in N2 (hypoxia, approximately 5,300 m above sea level). With hypoxia, exercise PaO2 dropped to 31-34 mmHg and arterial O2 content (CaO2) was reduced by 35% (P < 0.001). Forty-one percent of the reduction in CaO2 was explained by the lower inspired O2 pressure (PiO2) in hypoxia, whereas the rest was due to the impairment of the pulmonary gas exchange, as reflected by the higher alveolar-arterial O2 difference in hypoxia (P < 0.05). Hypoxia caused a 47% decrease in VO2 max (a greater fall than accountable by reduced CaO2). Peak cardiac output decreased by 17% (P < 0.01), due to equal reductions in both peak heart rate and stroke VOlume (P < 0.05). Peak leg blood flow was also lower (by 22%, P < 0.01). Consequently, systemic and leg O2 delivery were reduced by 43 and 47%, respectively, with hypoxia (P < 0.001) correlating closely with VO2 max (r = 0.98, P < 0.001). Therefore, three main mechanisms account for the reduction of VO2 max in severe acute hypoxia: 1) reduction of PiO2, 2) impairment of pulmonary gas exchange, and 3) reduction of maximal cardiac output and peak leg blood flow, each explaining about one-third of the loss in VO2 max.

Effect of blood haemoglobin concentration on V(O2,max) and cardiovascular function in lowlanders acclimatised to 5260 m

The principal aim of this investigation was to determine the influence of blood haemoglobin concentration ([Hb]) on maximal exercise capacity and maximal O(2) consumption (V(O(2),max)) in healthy subjects acclimatised to high altitude. Secondarily, we examined the effects of [Hb] on the regulation of cardiac output (CO), blood pressure and muscular blood flow (LBF) during exercise. Eight Danish lowlanders (three females and five males; 24 +/- 0.6 years, mean +/- S.E.M.) performed submaximal and maximal exercise on a cycle ergometer after 9 weeks at an altitude of 5260 m (Mt Chacaltaya, Bolivia). This was done first with the high [Hb] resulting from acclimatisation and again 2-4 days later, 1 h after isovolaemic haemodilution with Dextran 70 to near sea level [Hb]. After measurements at maximal exercise while breathing air at each [Hb], subjects were switched to hyperoxia (55 % O(2) in N(2)) and the measurements were repeated, increasing the work rate as tolerated. Hyperoxia increased maximal power output and leg V(O(2),max), showing that breathing ambient air at 5260 m, V(O(2),max) is limited by the availability of O(2) rather than by muscular oxidative capacity. Altitude increased [Hb] by 36 % from 136 +/- 5 to 185 +/- 5 g l(-1) (P < 0.001), while haemodilution (replacing 1 l of blood with 1 l of 6 % Dextran) lowered [Hb] by 24 % to 142 +/- 6 g l(-1) (P < 0.001). Haemodilution had no effect on maximal pulmonary or leg V(O(2),max), or power output. Despite higher LBF, leg O(2) delivery was reduced and maximal V(O(2)) was thus maintained by higher O(2) extraction. While CO increased linearly with work rate irrespective of [Hb] or inspired oxygen fraction (F(I,O(2))), both LBF and leg vascular conductance were systematically higher when [Hb] was low. Close and significant relationships were seen between LBF (and CO) and both plasma noradrenaline and K(+) concentrations, independently of [Hb] and F(I,O(2)). In summary, under conditions where O(2) supply limits maximal exercise, the increase in [Hb] with altitude acclimatisation does not improve maximal exercise capacity or V(O(2),max), and does not alter peak CO. However, LBF and vascular conductance are higher at altitude when [Hb] is lowered to sea level values, with both relating closely to catecholamine and potassium concentrations. This suggests that the lack of effect of [Hb] on V(O(2),max) may involve reciprocal changes in LBF via local metabolic control of the muscle vasculature.

The re-establishment of the normal blood lactate response to exercise in humans after prolonged acclimatization to altitude

1. One to five weeks of chronic exposure to hypoxia has been shown to reduce peak blood lactate concentration compared to acute exposure to hypoxia during exercise, the high altitude 'lactate paradox'. However, we hypothesize that a sufficiently long exposure to hypoxia would result in a blood lactate and net lactate release from the active leg to an extent similar to that observed in acute hypoxia, independent of work intensity. 2. Six Danish lowlanders (25-26 years) were studied during graded incremental bicycle exercise under four conditions: at sea level breathing either ambient air (0 m normoxia) or a low-oxygen gas mixture (10 % O(2) in N(2), 0 m acute hypoxia) and after 9 weeks of acclimatization to 5260 m breathing either ambient air (5260 m chronic hypoxia) or a normoxic gas mixture (47 % O(2) in N(2), 5260 m acute normoxia). In addition, one-leg knee-extensor exercise was performed during 5260 m chronic hypoxia and 5260 m acute normoxia. 3. During incremental bicycle exercise, the arterial lactate concentrations were similar at sub-maximal work at 0 m acute hypoxia and 5260 m chronic hypoxia but higher compared to both 0 m normoxia and 5260 m acute normoxia. However, peak lactate concentration was similar under all conditions (10.0 +/- 1.3, 10.7 +/- 2.0, 10.9 +/- 2.3 and 11.0 +/- 1.0 mmol l(-1)) at 0 m normoxia, 0 m acute hypoxia, 5260 m chronic hypoxia and 5260 m acute normoxia, respectively. Despite a similar lactate concentration at sub-maximal and maximal workload, the net lactate release from the leg was lower during 0 m acute hypoxia (peak 8.4 +/- 1.6 mmol min(-1)) than at 5260 m chronic hypoxia (peak 12.8 +/- 2.2 mmol min(-1)). The same was observed for 0 m normoxia (peak 8.9 +/- 2.0 mmol min(-1)) compared to 5260 m acute normoxia (peak 12.6 +/- 3.6 mmol min(-1)). Exercise after acclimatization with a small muscle mass (one-leg knee-extensor) elicited similar lactate concentrations (peak 4.4 +/- 0.2 vs. 3.9 +/- 0.3 mmol l(-1)) and net lactate release (peak 16.4 +/- 1.8 vs. 14.3 mmol l(-1)) from the active leg at 5260 m chronic hypoxia and 5260 m acute normoxia. 4. In conclusion, in lowlanders acclimatized for 9 weeks to an altitude of 5260 m, the arterial lactate concentration was similar at 0 m acute hypoxia and 5260 m chronic hypoxia. The net lactate release from the active leg was higher at 5260 m chronic hypoxia compared to 0 m acute hypoxia, implying an enhanced lactate utilization with prolonged acclimatization to altitude. The present study clearly shows the absence of a lactate paradox in lowlanders sufficiently acclimatized to altitude.

["CADASIL"--a newly discovered hereditary cerebrovascular disease]

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leucoencephalopathy) is a newly discovered inherited cerebrovascular disease characterized clinically by recurrent stroke-like incidents, dementia and often pseudobulbar palsy. Neuroimaging reveals intensive subcortical changes and pathologically one finds apparently systemic changes concerning the vessels such as thickening of the vessel wall, loss of smooth muscle cells and patches of granular material of unknown origin. The disease is not associated with atherosclerosis and vascular risk factors are missing or few. The CADASIL-locus maps to chromosome 19, but the gene has not yet been identified. Treatment and pathogenesis are unknown. In a Danish stroke population (The Copenhagen Stroke Study) no CADASIL-suspected cases were found among patients < or = 55 years, indicating a rare disease as far as Denmark is concerned.

[Long-term results of ileorectal anastomosis in the treatment of ulcerative colitis]

During the period 1951 to 1987, ileorectal anastomosis in one or two seances, depending upon the activity of the disease, was carried out in 63 patients with ulcerative pancolitis. It is concluded that the operative procedure seen in relation to recent continence-retaining types of operation and despite the relatively great frequency of convertion of 20% will still constitute an alternative in surgical treatment of patients with ulcerative colitis.

The total content of vitamin D in human milk and cow's milk

1. It was shown that the water-soluble fraction of cow's milk and human milk did not possess significant antirachitic activity on rats. Whole cow's milk was found to contain 3.8 i.u. vitamin D/l. Whole human milk contained 15 i.u. vitamin D/l, of which 12 i.u. derived from the lipid fraction. 3. Thus the values found were much lower than the 204 i.u./l in cow's milk and 950 i.u./l in human milk given in the literature based on chemical determination of the sterol sulphate content.