Longitudinal patterns of inflammatory mediators after acute HIV infection correlate to intact and total reservoir.

Background: Despite the beneficial effects of antiretroviral therapy (ART) initiation during acute HIV infection (AHI), residual immune activation remains a hallmark of treated HIV infection. Methods: Plasma concentrations of 40 mediators were measured longitudinally in 39 early treated participants of a Belgian AHI cohort (HIV+) and in 21 HIV-negative controls (HIV-). We investigated the association of the inflammatory profile with clinical presentation, plasma viral load, immunological parameters, and in-depth characterization of the HIV reservoir. Results: While levels of most soluble mediators normalized with suppressive ART, we demonstrated the persistence of a pro-inflammatory signature in early treated HIV+ participants in comparison to HIV- controls. Examination of these mediators demonstrated a correlation with their levels during AHI, which seemed to be viremia-driven, and suggested involvement of an activated myeloid compartment, IFN-γ-signaling, and inflammasome-related pathways. Interestingly, some of these pro-inflammatory mediators correlated with a larger reservoir size and slower reservoir decay. In contrast, we also identified soluble mediators which were associated with favorable effects on immunovirological outcomes and reservoir, both during and after AHI. Conclusion: These data highlight how the persistent pro-inflammatory profile observed in early ART treated individuals is shaped during AHI and is intertwined with viral dynamics.

Loss of GM-CSF-dependent instruction of alveolar macrophages in COVID-19 provides a rationale for inhaled GM-CSF treatment.

GM-CSF promotes myelopoiesis and inflammation, and GM-CSF blockade is being evaluated as a treatment for COVID-19-associated hyperinflammation. Alveolar GM-CSF is, however, required for monocytes to differentiate into alveolar macrophages (AMs) that control alveolar homeostasis. By mapping cross-species AM development to clinical lung samples, we discovered that COVID-19 is marked by defective GM-CSF-dependent AM instruction and accumulation of pro-inflammatory macrophages. In a multi-center, open-label RCT in 81 non-ventilated COVID-19 patients with respiratory failure, we found that inhalation of rhu-GM-CSF did not improve mean oxygenation parameters compared with standard treatment. However, more patients on GM-CSF had a clinical response, and GM-CSF inhalation induced higher numbers of virus-specific CD8 effector lymphocytes and class-switched B cells, without exacerbating systemic hyperinflammation. This translational proof-of-concept study provides a rationale for further testing of inhaled GM-CSF as a non-invasive treatment to improve alveolar gas exchange and simultaneously boost antiviral immunity in COVID-19. This study is registered at ClinicalTrials.gov (NCT04326920) and EudraCT (2020-001254-22).

Efficacy and safety of the investigational complement C5 inhibitor zilucoplan in patients hospitalized with COVID-19: an open-label randomized controlled trial.

BACKGROUND: The efficacy and safety of complement inhibition in COVID-19 patients is unclear. METHODS: A multicenter randomized controlled, open-label trial. Hospitalized COVID-19 patients with signs of systemic inflammation and hypoxemia (PaO2/FiO2 below 350 mmHg) were randomized (2:1 ratio) to receive standard of care with or without the C5 inhibitor zilucoplan daily for 14 days, under antibiotic prophylaxis. The primary outcome was improvement in oxygenation at day 6 and 15. RESULTS: 81 patients were randomly assigned to zilucoplan (n = 55) or the control group (n = 26). 78 patients were included in the safety and primary analysis. Most were men (87%) and the median age was 63 years. The mean improvement in PaO2/FiO2 from baseline to day 6 was 56.4 mmHg in the zilucoplan group and 20.6 mmHg in the control group (mean difference + 35.8; 95% confidence interval (CI) - 9.4 to 80.9; p = 0.12), an effect also observed at day 15. Day 28 mortality was 9% in the zilucoplan and 21% in the control group (odds ratio 0.4; 95% CI 0.1 to 1.5). At long-term follow up, the distance walked in a 6-min test was 539.7 m in zilucoplan and 490.6 m in the control group (p = 0.18). Zilucoplan lowered serum C5b-9 (p < 0.001) and interleukin-8 (p = 0.03) concentration compared with control. No relevant safety differences between the zilucoplan and control group were identified. CONCLUSION: Administration of zilucoplan to COVID-19 patients in this proof-of-concept randomized trial was well tolerated under antibiotic prophylaxis. While not reaching statistical significance, indicators of respiratory function (PaO2/FiO2) and clinical outcome (mortality and 6-min walk test) suggest that C5 inhibition might be beneficial, although this requires further research in larger randomized studies.

A public health value-based healthcare paradigm for HIV.

BACKGROUND: HIV patients face considerable acute and chronic healthcare needs and battling the HIV epidemic remains of the utmost importance. By focusing on health outcomes in relation to the cost of care, value-based healthcare (VBHC) proposes a strategy to optimize quality of care and cost-efficiency. Its implementation may provide an answer to the increasing pressure to optimize spending in healthcare while improving patient outcomes. This paper describes a pragmatic value-based healthcare framework for HIV care. METHODS: A value-based HIV healthcare framework was developed during a series of roundtable discussions bringing together 16 clinical stakeholder representatives from the Belgian HIV reference centers and 2 VBHC specialists. Each round of discussions was focused on a central question translating a concept or idea to the next level of practical implementation: 1) how can VBHC principles be translated into value-based HIV care drivers; 2) how can these value-based HIV care divers be translated into value-based care objectives and activities; and 3) how can value-based HIV care objectives and activities be translated into value-based care indicators. Value drivers were linked to concrete objectives and activities using a logical framework approach. Finally, specific, measurable, and acceptable structure, process and outcomes indicators were defined to complement the framework. RESULTS: Our framework identifies 4 core value areas where HIV care would benefit most from improvements: Prevention, improvement of the cascade of care, providing patient-centered HIV care and sustaining a state-of-the-art HIV disease management context. These 4 core value areas were translated into 12 actionable core value objectives. For each objective, example activities were proposed. Indicators are suggested for each level of the framework (outcome indicators for value areas and objectives, process indicators for suggested activities). CONCLUSIONS: This framework approach outlines how to define a patient- and public health centered value-based HIV care paradigm. It proposes how to translate core value drivers to practical objectives and activities and suggests defining indicators that can be used to track and improve the framework's implementation in practice.

Effect of anti-interleukin drugs in patients with COVID-19 and signs of cytokine release syndrome (COV-AID): a factorial, randomised, controlled trial.

BACKGROUND: Infections with SARS-CoV-2 continue to cause significant morbidity and mortality. Interleukin (IL)-1 and IL-6 blockade have been proposed as therapeutic strategies in COVID-19, but study outcomes have been conflicting. We sought to study whether blockade of the IL-6 or IL-1 pathway shortened the time to clinical improvement in patients with COVID-19, hypoxic respiratory failure, and signs of systemic cytokine release syndrome. METHODS: We did a prospective, multicentre, open-label, randomised, controlled trial, in hospitalised patients with COVID-19, hypoxia, and signs of a cytokine release syndrome across 16 hospitals in Belgium. Eligible patients had a proven diagnosis of COVID-19 with symptoms between 6 and 16 days, a ratio of the partial pressure of oxygen to the fraction of inspired oxygen (PaO2:FiO2) of less than 350 mm Hg on room air or less than 280 mm Hg on supplemental oxygen, and signs of a cytokine release syndrome in their serum (either a single ferritin measurement of more than 2000 µg/L and immediately requiring high flow oxygen or mechanical ventilation, or a ferritin concentration of more than 1000 µg/L, which had been increasing over the previous 24 h, or lymphopenia below 800/mL with two of the following criteria: an increasing ferritin concentration of more than 700 µg/L, an increasing lactate dehydrogenase concentration of more than 300 international units per L, an increasing C-reactive protein concentration of more than 70 mg/L, or an increasing D-dimers concentration of more than 1000 ng/mL). The COV-AID trial has a 2 × 2 factorial design to evaluate IL-1 blockade versus no IL-1 blockade and IL-6 blockade versus no IL-6 blockade. Patients were randomly assigned by means of permuted block randomisation with varying block size and stratification by centre. In a first randomisation, patients were assigned to receive subcutaneous anakinra once daily (100 mg) for 28 days or until discharge, or to receive no IL-1 blockade (1:2). In a second randomisation step, patients were allocated to receive a single dose of siltuximab (11 mg/kg) intravenously, or a single dose of tocilizumab (8 mg/kg) intravenously, or to receive no IL-6 blockade (1:1:1). The primary outcome was the time to clinical improvement, defined as time from randomisation to an increase of at least two points on a 6-category ordinal scale or to discharge from hospital alive. The primary and supportive efficacy endpoints were assessed in the intention-to-treat population. Safety was assessed in the safety population. This study is registered online with ClinicalTrials.gov (NCT04330638) and EudraCT (2020-001500-41) and is complete. FINDINGS: Between April 4, and Dec 6, 2020, 342 patients were randomly assigned to IL-1 blockade (n=112) or no IL-1 blockade (n=230) and simultaneously randomly assigned to IL-6 blockade (n=227; 114 for tocilizumab and 113 for siltuximab) or no IL-6 blockade (n=115). Most patients were male (265 [77%] of 342), median age was 65 years (IQR 54-73), and median Systematic Organ Failure Assessment (SOFA) score at randomisation was 3 (2-4). All 342 patients were included in the primary intention-to-treat analysis. The estimated median time to clinical improvement was 12 days (95% CI 10-16) in the IL-1 blockade group versus 12 days (10-15) in the no IL-1 blockade group (hazard ratio [HR] 0·94 [95% CI 0·73-1·21]). For the IL-6 blockade group, the estimated median time to clinical improvement was 11 days (95% CI 10-16) versus 12 days (11-16) in the no IL-6 blockade group (HR 1·00 [0·78-1·29]). 55 patients died during the study, but no evidence for differences in mortality between treatment groups was found. The incidence of serious adverse events and serious infections was similar across study groups. INTERPRETATION: Drugs targeting IL-1 or IL-6 did not shorten the time to clinical improvement in this sample of patients with COVID-19, hypoxic respiratory failure, low SOFA score, and low baseline mortality risk. FUNDING: Belgian Health Care Knowledge Center and VIB Grand Challenges program.

A case of a surgical-site infection with Staphylococcus condimenti.

INTRODUCTION: Coagulase-negative staphylococci (CNS) are considered to have a medium or low pathogenic capacity when compared to S. aureus. Among the more harmless, CNS are those that are used in the food industry, represented by S. carnosus, whose genome has extensively been studied. Its genome was found to contain several genomic sequences that have a virulent function in the pathogenic S. aureus. Even though these genes are probably not virulent in S. carnosus, their presence might indicate a more virulent potential. We report the third clinical case associated with a surgical-site infection with S. condimenti, which belongs to these food industry related CNS. It corresponds to a blood stream infection, secondary to a surgical-site infection. RESULTS: Antibiotic susceptibility testing indicated a resistance to erythromycin and rifampicin, which was partly confirmed by the presence of a macrolide resistance gene by PCR screening for S. aureus virulence factors. Although no other putative virulence factors were detected, this organism managed to cause a severe post-operative wound infection. CONCLUSION: This case shows that CNS that are currently used in the food industry may play a role in human infection. With technologies such as MALDI-TOF, pathogens that are regarded non-pathogenic could be identified more often. Therefore, the risk of different Staphylococcus strains used in the food industry must be better assessed.

Bone scan findings in erythromelalgia.

The use of hyaluronic acid nanoshells has been proposed to encapsulate prodrugs and exploit the mechanisms of interactions between living cells, like endocytes or cancer cells and hyaluronic acid, which is a natural component of the extracellular matrix. In this review we describe the potential and the limits of this promising research trend and discuss the theoretical advantages of such an engineering approach. Is it a possible scalability to increase the efficacy and biodegradability of molecules like contrast media and radiotracers especially for neuroradiology and nuclear medicine studies.

Temocillin dosing in haemodialysis patients based on population pharmacokinetics of total and unbound concentrations and Monte Carlo simulations.

Objectives: To develop a population model describing temocillin pharmacokinetics (PK) in patients undergoing haemodialysis and investigate how pharmacokinetic/pharmacodynamic (PD) targets can be met with different dosage regimens. Patients and methods: Sixteen patients received the currently licenced dosing of 1, 2 or 3 g of temocillin (total of 61 doses) corresponding to an inter-dialytic period of 20, 44 or 68 h, respectively, and a dialysis period of 4 h. A non-linear mixed-effects model was developed jointly for total and unbound temocillin serum concentrations. The performance of clinically feasible dosing regimens was evaluated using a 5000-subject Monte Carlo (MC) simulation for determining the highest MIC for which the PK/PD target of 40%ƒT>MIC would be reached in 90% of patients [probability of target attainment (PTA)]. This PK study was registered at ClinicalTrials.gov (NCT02285075). Results: Temocillin unbound and total serum concentrations (429 samples) were used to fit an open two-compartment model with non-linear albumin binding and first-order elimination. In addition to total body clearance, dialysis clearance was modelled using the Michaels function. The currently licenced dosing achieved a 90% PTA for an MIC up to 8 mg/L. A new temocillin dosage regimen was designed that would achieve a 90% PTA for an MIC of 16 mg/L (MIC90 of target organisms) adjusted to patient weight and inter-dialytic period. Conclusions: Currently licensed dosage regimen is suboptimal for MICs >8 mg/L (frequently found in clinical isolates). Model-based simulations allowed suggestion of a new dosage regimen with improved probability of microbiological success, applicability in routine clinical practice and more appropriate for empirical therapy.

Thrice-weekly temocillin administered after each dialysis session is appropriate for the treatment of serious Gram-negative infections in haemodialysis patients.

In patients with end-stage renal disease (ESRD) treated with intermittent haemodialysis, a limited number of antibiotics have been studied for their suitability for parenteral administration after dialysis sessions only in a thrice-weekly regimen. Temocillin is a ß-lactam antibiotic with a long half-live and enhanced activity against most Gram-negative bacteria, including extended-spectrum ß-lactamase-producers, thus making it an ideal candidate for use in this setting. This study aimed to evaluate the reliability of thrice-weekly parenteral temocillin in haemodialysis patients by characterising the pharmacokinetics of total and free temocillin. Free and total temocillin concentrations were determined with a validated HPLC method in 448 samples derived from 48 administration cycles in 16 patients with ESRD treated with intermittent haemodialysis and temocillin. Pharmacokinetics were non-linear partly due to saturation in protein binding. Median clearance and half-life for the free drug during intradialysis and interdialysis periods were 113 mL/min vs. 26 mL/min and 3.6 h vs. 24 h, respectively, with dialysis extracting approximately one-half of the residual concentration. The free temocillin concentration remained >16 mg/L (MIC90 threshold for most Enterobacteriaceae) during 48%, 67% and 71% of the dosing interval for patients receiving 1 g q24h, 2 g q48h and 3 g q72h, respectively, suggesting appropriate exposure for the two latter therapeutic schemes. Temocillin administered on dialysis days only in a dosing schedule of 2 g q48h and 3 g q72h is appropriate for the treatment of serious and/or resistant Gram-negative infections in patients with ESRD undergoing intermittent haemodialysis. These doses are higher than those previously recommended.

The ABC of pneumococcal infections and vaccination in patients with chronic kidney disease.

BACKGROUND: In the general population, pneumococcal polysaccharide vaccines (PPV) decrease the incidence of invasive pneumococcal disease (IPD) whereas the impact on the prevention of noninvasive pneumococcal disease is less clear. As compared with PPV, pneumococcal conjugate vaccines (PCV) provoke a higher, longer-lasting immune response resulting in a 45% decreased incidence in vaccine-type pneumonia, and a 75% decrease in vaccine-type IPD. METHODS: Literature review on pneumococcal vaccination in end-stage renal disease. RESULTS: As compared with the general population, patients with chronic kidney disease (CKD) suffer increased mortality and morbidity from pneumococcal disease (PD), being up to 10-fold for those treated with dialysis. Numerous, usually small and methodological heterogeneous studies demonstrate that PPV provokes a serological response in dialysis patients, kidney transplant recipients, children with nephrotic syndrome and CKD patients receiving immunosuppressive medication. This response is of less intensity and duration than in healthy controls. Similar observations were made for the PCV. The protective value of these vaccine-elicited anti-pneumococcal antibodies in the CKD population remains to be substantiated. For patients treated with dialysis, epidemiological data demonstrate a correlation-which does not equal causality-between pneumococcal vaccination status and a slightly decreased total mortality. Clinical outcome data on the effectiveness of pneumococcal vaccination in the prevention of morbidity and mortality in the CKD population are lacking. CONCLUSIONS: Awaiting better evidence, pneumococcal vaccination should be advocated in all patients with CKD, as early in their disease course as possible. The ACIP schedule recommends a PCV-13 prime vaccination followed by a PPV-23 repeated vaccine at least 8 weeks later in pneumococcal non-vaccinated patients, and a PCV-13 vaccine at least 1 year after the latest PPV vaccine in previously vaccinated patients. In the UK, vaccination with PPV-23 only is recommended. There exist no good data supporting re-vaccination after 5 years in the dialysis population.

Multiple nocardial abscesses of the brainstem and spinal cord diagnosed after an open biopsy through a cervical partial central corpectomy: case report.

Nocardiosis of the central nervous system is a challenging and difficult diagnosis for the clinician. The combination of infections of the brain and spinal cord is even more rare. The authors report on a patient with multiple lesions in the brainstem and cervical spinal cord. This 81-year-old immunocompetent woman presented with symptoms of progressive walking difficulty and ataxia. The results of an extensive workup with laboratory investigation, MRI, lumbar puncture, positron emission tomography (PET), and bone marrow biopsy remained inconclusive. Only after an open biopsy of a cervical lesion by an anterior approach through a partial central corpectomy of the cervical spine, was the diagnosis of nocardiosis made, allowing for specific antibiotic treatment.

Dose-finding study of rivaroxaban in hemodialysis patients.

BACKGROUND: Use of vitamin K antagonists for the prevention of stroke and systemic embolism in dialysis patients with nonvalvular atrial fibrillation is controversial. However, no good alternatives presently are available. The anti-factor Xa antagonist rivaroxaban is contraindicated for lack of pharmacokinetic, pharmacodynamic, and clinical data. This study aims to characterize the pharmacokinetics/pharmacodynamics of rivaroxaban in maintenance hemodialysis patients. STUDY DESIGN: Pharmacokinetic and pharmacodynamic study. SETTING & PARTICIPANTS: 18 maintenance hemodialysis patients without residual kidney function at 2 centers. DRUG ADMINISTRATION, OUTCOMES, & MEASUREMENTS: (1) A single dose of 10mg of rivaroxaban was administered at the end of each of 3 consecutive dialysis sessions and area under the curve (AUC) and the effect on coagulation parameters were measured for 44 hours thereafter. (2) A single dose of 10mg of rivaroxaban was given 6 to 8 hours before a dialysis session and the effect of dialysis on rivaroxaban concentrations was evaluated. (3) To assess potential accumulation, 10mg of rivaroxaban was given once daily and AUC was measured during 24 hours on days 1 and 7. RESULTS: Mean AUC0-44 of rivaroxaban plasma concentrations after a single dose of 10mg was 2,072µg/L/h, mean maximum concentration was 172.6µg/L, and mean terminal elimination half-life was 8.6 hours. Dialysis had no appreciable effect on rivaroxaban plasma concentrations. Mean trough concentration after multiple daily doses of 10mg was 20.2µg/L. LIMITATIONS: Higher rivaroxaban doses and patients with substantial residual kidney function were not studied. CONCLUSIONS: A 10-mg dose of rivaroxaban in hemodialysis patients without residual kidney function results in drug exposure similar as published for 20mg in healthy volunteers. Rivaroxaban is not eliminated by dialysis. There is no accumulation after multiple daily dosing. The efficacy and safety of rivaroxaban in hemodialysis patients should be the subject of a large randomized trial.

A patient-centered vision of care for ESRD: dialysis as a bridging treatment or as a final destination?

The ESRD population is heterogeneous, including patients without severe comorbidity for whom dialysis is a bridge to transplantation or a long-term maintenance treatment, as well as patients with a limited life expectancy as a result of advanced age or severe comorbidity for whom dialysis will be the final treatment destination. The complex medical and social context of this latter group fits poorly in the homogeneous, disease-centered, and process-driven approach of many clinical practice guidelines for dialysis. In this commentary, we argue that the standards of treatment allocated to each individual patient should be defined not merely by his or her disease state, but also by his or her preferences and prognosis. In this more patient-centered approach, three attainable treatment goals with a corresponding therapeutic approach could be defined: (1) dialysis as bridging or long-term maintenance treatment, (2) dialysis as final treatment destination, and (3) active medical management without dialysis. For patients with a better overall prognosis, this approach will emphasize complication prevention and long-term survival. For patients with a limited overall prognosis, strictly disease-centered interventions often impose a treatment burden that does not translate into a proportional improvement in quantity or quality of life. For these patients, a patient-centered approach will place more emphasis on palliative management strategies that are less disease specific.

Hemodialysis catheter design and catheter performance: a randomized controlled trial.

BACKGROUND: A complication of long-term use of tunneled cuffed catheters for hemodialysis is the high rate of infection and thrombus-related dysfunction. Specific mechanical features of tunneled cuffed catheters may improve hemodynamic performance and decrease thrombosis and infection rates. However, there currently is no proven advantage of one design over another. STUDY DESIGN: Single-center randomized clinical trial. SETTING & PARTICIPANTS: 302 hemodialysis patients who required a tunneled cuffed catheter as temporary or definite vascular access. INTERVENTION: Palindrome Symmetric Tip Dialysis Catheter or HemoStar Long-Term Hemodialysis Catheter. OUTCOMES & MEASUREMENTS: The primary end point was primary assisted patency. Secondary end points were incidence of catheter-related bloodstream infections (CRBSIs), thrombosis, and 2 indicators of rheologic function: mean effective blood flow rate and urokinase use. RESULTS: Mean primary assisted patency was 135.9 days for Palindrome and 136.5 days for HemoStar (P=0.8). Definite CRBSI occurred in 0.24 and 0.10/1,000 catheter-days for Palindrome and HemoStar, respectively (P=0.3). Removal rates for thrombosis that could not be resolved with thrombolysis were 0.53 and 0.43/1,000 catheter-days for Palindrome and HemoStar, respectively (P=0.7). Urokinase use was lower for Palindrome than for HemoStar, as evidenced by a lower number of urokinase infusions/1,000 catheter-days (17 and 35; P<0.001) and higher number of catheters that never required thrombolysis (58% and 45%; P=0.03). Mean effective blood flow rate was higher for Palindrome than for HemoStar (333 and 304mL/min; P<0.001). LIMITATIONS: Single-center nonblinded trial. CONCLUSIONS: Primary assisted patency and incidence of infection and thrombosis were similar for both catheter types. The Palindrome catheter required less thrombolysis and achieved higher blood flow rates than the HemoStar catheter. These findings suggest that mechanical catheter design may improve catheter rheology, but does not affect risks for thrombosis and infection and hence catheter survival.

Vancomycin: the tale of the vanquisher and the pyrrhic victory.

Vancomycin has been the antibiotic of choice in the treatment of methicillin-resistant Staphylococcus aureus infections for decades. But relatively recently, vancomycin-intermediate-susceptible S. aureus (VISA) have been reported. Phenotypically, VISA are characterized by thicker cell walls, requiring higher concentrations of vancomycin for inhibition of bacterial cell growth. Vancomycin-intermediate-susceptible S. aureus represent just the tip of the iceberg of an insidious loss of vancomycin susceptibility in staphylococci. Increasing proportions of S. aureus isolates have higher minimum inhibitory concentrations that are still within the officially susceptible range, a characteristic that is associated with treatment failure. The most important risk factor for decreased vancomycin susceptibility is in vivo selection pressure. To prevent the development of VISA, prolonged or inappropriate use of vancomycin and suboptimal vancomycin levels should be avoided. Trough serum vancomycin concentrations of 15 - 20 mg/L for intermittent dosing and plateau serum vancomycin concentrations of 20 - 25 mg/L for continuous infusions are therefore currently recommended. The widespread clinical application of these intensive dosing regimens has resulted in an increasing awareness of vancomycin-induced nephrotoxicity, which is especially relevant in patients whose renal function is already compromised. This narrow therapeutic-toxic window reinforces the use of rigorous dosing protocols. In hemodialysis, the use of a vancomycin dose calculator permits achievement of target concentrations in most patients. In peritoneal dialysis (PD), intermittent vancomycin dosing regimens often lead to low end-of-dwell concentrations. On the other hand, a continuous vancomycin dosing regimen after a loading dose offers the desired combination of high local levels without toxic systemic levels.

Development and validation of a high performance liquid chromatography assay for the determination of temocillin in serum of haemodialysis patients.

Therapeutic drug monitoring of ß-lactams can be useful for the optimization of therapy, especially when little reference data exist on actual pharmacokinetic profiles such as in patients undergoing haemodialysis. There is no reported validated method for temocillin assay in serum samples, and preliminary studies evidenced potential for interferences by acidic metabolites and co-administered drugs in patients with advanced kidney failure. This paper describes a fully validated method for the determination of temocillin in human serum, and its applicability in haemodialysis patients. Temocillin was extracted from human serum by a solid phase extraction methodology, and then assayed by reversed-phase HPLC with UV-detection. The method was validated according to the accuracy profile methodology, using total error to verify the trueness, precision and overall accuracy. It showed high specificity and precision and was accurate in the concentration range of 5-400 mg/L. LOD and LOQ were 1.2 and 5 mg/L, respectively. No interference with 30 co-administered drugs was evidenced. The method was successfully applied to clinical samples from haemodialysis patients, showing a high degree of dialysability of temocillin.

Should we screen for coronary artery disease in asymptomatic chronic dialysis patients?

The hemodialysis population is characterized by a high prevalence of 'asymptomatic' coronary artery disease (CAD), which should be interpreted differently from asymptomatic disease in the general population. A hemodynamically significant stenosis may not become clinically apparent owing to impaired exercise tolerance and autonomic neuropathy. The continuous presence of silent ischemia may cause heart failure, arrhythmias, and sudden death. Whether revascularization of an asymptomatic dialysis patient improves outcome remains a moot point, although several observational studies and one small RCT suggest a benefit. It can therefore be defended to screen asymptomatic dialysis patients for CAD. A number of noninvasive screening tests are available, but none has proved equally practical and reliable in the dialysis population as in the general population. Myocardial perfusion scintigraphy (MPS) before and after a pharmacological stress such as dipyridamole can reveal both ischemia and myocardial scarring. When compared with coronary angiography, low sensitivities were reported and attributed to impaired vasodilation to dipyridamole in dialysis patients. A more likely explanation is that not every anatomical stenosis will lead to impaired coronary blood flow on MPS. Numerous studies have shown an incremental prognostic value of dipyridamole-MPS over clinical data for prediction of adverse cardiac events, in some studies even over coronary angiography. Pending the availability of high-quality evidence, in our opinion asymptomatic dialysis patients could undergo dipyridamole-MPS, followed by coronary angiography in case of an abnormal scan. This combined physiological and anatomical evaluation of the coronary circulation allows us to determine which coronary stenosis is clinically relevant and therefore should be revascularized.