Andreas Huber

The role of automated urine particle flow cytometry in clinical practice

Urine particle flow cytometers (UFC) have improved count precision and accuracy compared to visual microscopy and offer significant labor saving. The absence of an internationally recognized reference measurement procedure, however, is a serious drawback to their validation. Chamber counting by phase contrast microscopy of supravitally-stained uncentrifuged urine is considered the best candidate for reference. The UF-100 (Sysmex Corporation, Japan) identifies RBC, WBC, squamous epithelial cells, transitional epithelial and renal tubular cells (SRC), bacteria, hyaline and inclusional casts, yeast-like cells, crystals and spermatozoa, using argon laser flow cytometry. Evaluations have established acceptable linearity over useful working ranges, with an imprecision that is consistently and significantly less than microscopy, and with negligible carry-over. Comparisons of UFC with chamber counts, quantitative urine microscopy, sediment counts, test strips, bacterial culture and urine density are reviewed. Clinical studies include diagnosis and monitoring of urinary tract infection; localization of the sites of hematuria; and diagnosis, monitoring and exclusion of renal disease. The most popular approach is to combine test strips with UFC for primary screening either always by both methods or by using test strips for analytes unrelated to particles analyzed by UFC. Expert systems now exist combining both test modalities based on user definable decision rules. The implementation of such a strategy significantly reduces microscopy review and saves time and expense without diminishing clinical utility.

Glucagon-Like Peptide-1 Is Involved in Sodium and Water Homeostasis in Humans

In previous studies with glucagon-like peptide-1 (GLP-1) we have observed that this peptide modulates fluid intake and increases renal sodium excretion in healthy volunteers and in patients with diabetes mellitus type 2. The effect of GLP-1 on thirst, water intake and on osmoregulation has, however, not been examined in detail in humans. Methods: Seventeen healthy male subjects were enrolled in two double-blind, placebo-controlled studies. In study part A, 8 volunteers participated in a protocol with an intravenous salt load of 26.7 ± 0.9 g comparing the effect of an infusion of GLP-1 (1.5 pmol/kg × min) to isotonic saline (placebo). Sodium excretion and water intake were measured. In part B, 9 volunteers were challenged with an oral salt load of 27.7 ± 0.5 g; sodium excretion and water intake were determined comparing an infusion of GLP-1 (1.5 pmol/kg × min) to isotonic saline (placebo). In part C, intestinal biopsies along the gastrointestinal tract were obtained from 14 healthy subjects. Expression of human GLP-1 receptor mRNA was measured by real-time polymerase chain reaction. Results: In study part A, an increase in renal sodium excretion was demonstrated: FeNa rose from 1.6 ± 0.3 (placebo) to 2.7 ± 0.2% (GLP-1; p = 0.0005). There was no difference in water consumption between the two treatments: 1,291 ± 69 (saline) vs. 1,228 ± 74 ml (GLP-1; p = 0.49). In part B, an oral salt challenge of 27.7 ± 0.5 g led to an increased renal excretion of sodium during GLP-1: FeNa increased from 1.6 ± 0.2% (placebo) to 2.0 ± 0.2% (GLP-1; p = 0.012). In contrast to part A, oral water intake was reduced by 36% under GLP-1 treatment: 1,848 ± 331 ml (placebo) vs. 1,181 ± 177 ml (GLP-1; p = 0.0414). Three subjects in part B did not finish treatment with GLP-1 because of diarrhea. Human GLP-1 receptor mRNA expression was highest in the proximal human small intestine compared to terminal ileum and colon (p < 0.02). Conclusions: GLP-1 acts on renal tissue reducing sodium absorption, probably via similar sodium transporters, which also may be localized in the gastrointestinal tract. This hypothesis needs to be confirmed by further studies.

Biomarker-enhanced triage in respiratory infections: a proof-of-concept feasibility trial

Concerns about inadequate performance and complexity limit routine use of clinical risk scores in lower respiratory tract infections. Our aim was to study feasibility and effects of adding the biomarker proadrenomedullin (proADM) to the confusion, urea >7 mmol·L−1, respiratory rate ≥30 breaths·min−1, blood pressure <90 mmHg (systolic) or ≤60 mmHg (diastolic), age ≥65 years (CURB-65) score on triage decisions and length of stay. In a randomised controlled proof-of-concept intervention trial, triage and discharge decisions were made for adults with lower respiratory tract infection according to interprofessional assessment using medical and nursing risk scores either without (control group) or with (proADM group) knowledge of proADM values, measured on admission, and on days 3 and 6. An adjusted generalised linear model was calculated to investigate the effect of our intervention. On initial presentation the algorithms were overruled in 123 (39.3%) of the cases. Mean length of stay tended to be shorter in the proADM (n=154, 6.3 days) compared with the control group (n=159, 6.8 days; adjusted regression coefficient -0.19, 95% CI -0.41–0.04; p=0.1). This trend was robust in subgroup analyses and for overall length of stay within 90 days (7.2 versus 7.9 days; adjusted regression coefficient -0.18, 95% CI -0.40–0.05; p=0.13). There were no differences in adverse outcomes or readmission. Logistic obstacles and overruling are major challenges to implement biomarker-enhanced algorithms in clinical settings and need to be addressed to shorten length of stay. Proof-of-concept trial: how to shorten LOS in patients with LRTIs by reducing medically unnecessary days in the hospital http://ow.ly/nI7z4

Optimizing triage and hospitalization in adult general medical emergency patients: the triage project

BackgroundPatients presenting to the emergency department (ED) currently face inacceptable delays in initial treatment, and long, costly hospital stays due to suboptimal initial triage and site-of-care decisions. Accurate ED triage should focus not only on initial treatment priority, but also on prediction of medical risk and nursing needs to improve site-of-care decisions and to simplify early discharge management. Different triage scores have been proposed, such as the Manchester triage system (MTS). Yet, these scores focus only on treatment priority, have suboptimal performance and lack validation in the Swiss health care system. Because the MTS will be introduced into clinical routine at the Kantonsspital Aarau, we propose a large prospective cohort study to optimize initial patient triage. Specifically, the aim of this trial is to derive a three-part triage algorithm to better predict (a) treatment priority; (b) medical risk and thus need for in-hospital treatment; (c) post-acute care needs of patients at the most proximal time point of ED admission.Methods/designProspective, observational, multicenter, multi-national cohort study. We will include all consecutive medical patients seeking ED care into this observational registry. There will be no exclusions except for non-adult and non-medical patients. Vital signs will be recorded and left over blood samples will be stored for later batch analysis of blood markers. Upon ED admission, the post-acute care discharge score (PACD) will be recorded. Attending ED physicians will adjudicate triage priority based on all available results at the time of ED discharge to the medical ward. Patients will be reassessed daily during the hospital course for medical stability and readiness for discharge from the nurses and if involved social workers perspective. To assess outcomes, data from electronic medical records will be used and all patients will be contacted 30 days after hospital admission to assess vital and functional status, re-hospitalization, satisfaction with care and quality of life measures.We aim to include between 5000 and 7000 patients over one year of recruitment to derive the three-part triage algorithm. The respective main endpoints were defined as (a) initial triage priority (high vs. low priority) adjudicated by the attending ED physician at ED discharge, (b) adverse 30 day outcome (death or intensive care unit admission) within 30 days following ED admission to assess patients risk and thus need for in-hospital treatment and (c) post acute care needs after hospital discharge, defined as transfer of patients to a post-acute care institution, for early recognition and planning of post-acute care needs. Other outcomes are time to first physician contact, time to initiation of adequate medical therapy, time to social worker involvement, length of hospital stay, reasons for discharge delays, patient’s satisfaction with care, overall hospital costs and patients care needs after returning home.DiscussionUsing a reliable initial triage system for estimating initial treatment priority, need for in-hospital treatment and post-acute care needs is an innovative and persuasive approach for a more targeted and efficient management of medical patients in the ED. The proposed interdisciplinary , multi-national project has unprecedented potential to improve initial triage decisions and optimize resource allocation to the sickest patients from admission to discharge. The algorithms derived in this study will be compared in a later randomized controlled trial against a usual care control group in terms of resource use, length of hospital stay, overall costs and patient’s outcomes in terms of mortality, re-hospitalization, quality of life and satisfaction with care.Trial registrationClinicalTrials.gov Identifier, NCT01768494

Symptoms and Characteristics of Individuals with Profound Hyponatremia: A Prospective Multicenter Observational Study

To assess symptoms and characteristics of hyponatremia, the most common electrolyte disturbance in hospitalized individuals and a condition that is associated with substantial morbidity and mortality.

L-PGDS (Betatrace Protein) Inhibits Astrocyte Proliferation and Mitochondrial ATP Production in Vitro

L-PGDS is the most abundant protein present in the cerebrospinal fluid (CSF). Although CSF was believed to be homogenous in content, a previous study has showed that a marked concentration gradient of L-PGDS exists between the spinal CSF and the CSF in the subarachnoid space of patients with optic nerve disease (papilledema and normal-tension glaucoma). Astrocytes play a critical role in maintaining the integrity of axon function in the central nervous system and specifically in the optic nerve, and we therefore investigated the biochemical effects of L-PGDS on the proliferation of astrocytes and on the production of adenosine triphosphate (ATP) by astrocyte mitochondria. We found an inhibitory effect of L-PGDS on both proliferation of astrocytes and production of astrocyte ATP. The concentrations that inhibited astrocyte proliferation and ATP production were in the range measured in patients with idiopathic intracranial hypertension and in patients with normal-tension glaucoma. As the CSF is in contact with axons and mitochondria of the optic nerve (Bristow et al. Archives of Ophthalmology, 120, 791–796, 2002), we postulate that a change in the concentration of CSF protein such as L-PGDS could exercise a harmful effect on these structures.

Optimised patient transfer using an innovative multidisciplinary assessment in Kanton Aargau (OPTIMA I): an observational survey in lower respiratory tract infections.

BACKGROUND Current medical scores have limited efficiency and safety profiles to enable assignment to the most appropriate treatment site in patients with lower respiratory tract infections (LRTIs). We describe our current triage practice and assess the potential of a combination of CURB65 with proadrenomedullin (ProADM) levels for triage decisions. METHODS Consecutive patients with LRTIs presenting to our emergency department were prospectively followed and retrospectively classified according to CURB65 and ProADM levels (CURB65-A). Low medical risk patients were further subgrouped according to biopsychosocial and functional risks. We compared the proportion of patients virtually allocated to triage sites with actual triage decisions and assessed the added impact of ProADM in a subgroup. RESULTS Overall, 93% of 146 patients were hospitalised. Among the 138 patients with available CURB65-A, 17.4% had a low medical risk indicating possible treatment in an outpatient or non-acute medical setting; 34.1% had an intermediate medical risk (short-hospitalisation); and 48.6% had a high medical risk (hospitalisation). Fewer patients were in a low CURB65-A class (I) than a low CURB65 class (0,1) (17.4% vs. 46.3%, p <0.001). Mean length of hospitalisation was 9.8 days including 3.6 days after reaching medical stability. In 60.3% of patients, hospitalisation was prolonged after medical stability mainly for medical reasons. CONCLUSIONS Current rates of hospitalisation are high in patients with LRTI and length of stay frequently extended beyond time of medical stabilization. The lower proportion of patients reclassified as low risk by adding ProADM to the CURB65 score might improve confidence in the triage algorithm.

Unraveling the Link between Malnutrition and Adverse Clinical Outcomes: Association of Acute and Chronic Malnutrition Measures with Blood Biomarkers from Different Pathophysiological States

Background and Aims: Malnutrition is associated with poor clinical outcomes. Whether there is a causal relationship or it merely mirrors a severe patient condition remains unclear. We examined the association of malnutrition with biomarkers characteristic of different pathophysiological states to better understand the underlying etiological mechanisms. Methods: We prospectively followed consecutive adult medical inpatients. Multivariable regression models were used to investigate the associations between malnutrition - as assessed using the Nutritional Risk Screening (NRS 2002) - and biomarkers linked to inflammation, stress, renal dysfunction, nutritional status and hematologic function. Results: A total of 529 patients were included. In a fully adjusted model, malnutrition was significantly associated with the inflammatory markers procalcitonin (0.20, 95% CI 0.03-0.37), proadrenomedullin (0.28, 95% CI 0.12-0.43) and albumin (-0.39, 95% CI -0.57 to -0.21), the stress marker copeptin (0.34, 95% CI 0.17-0.51), the renal function marker urea (0.23, 95% CI 0.07-0.38), the nutritional markers vitamin D25 (-0.22, 95% CI -0.41 to -0.02) and corrected calcium (0.29, 95% CI 0.10-0.49) and the hematological markers hemoglobin (-0.27, 95% CI -0.43 to -0.10) and red blood cell distribution width (0.26, 95% CI 0.07-0.44). Subgroup analysis suggested that acute malnutrition rather than chronic malnutrition was associated with elevated biomarker levels. Conclusion: Acute malnutrition was associated with a pronounced inflammatory response and an alteration in biomarkers associated with different pathophysiological states. Interventional trials are needed to prove causality.

Systematic review regarding metabolic profiling for improved pathophysiological understanding of disease and outcome prediction in respiratory infections

Metabolic profiling through targeted quantification of a predefined subset of metabolites, performed by mass spectrometric analytical techniques, allows detailed investigation of biological pathways and thus may provide information about the interaction of different organic systems, ultimately improving understanding of disease risk and prognosis in a variety of diseases. Early risk assessment, in turn, may improve patient management in regard to cite-of-care decisions and treatment modalities. Within this review, we focus on the potential of metabolic profiling to improve our pathophysiological understanding of disease and management of patients. We focus thereby on lower respiratory tract infections (LRTI) including community-acquired pneumonia (CAP) and chronic obstructive pulmonary disease (COPD), an important disease responsible for high mortality, morbidity and costs worldwide. Observational data from numerous clinical and experimental studies have provided convincing data linking metabolic blood biomarkers such as lactate, glucose or cortisol to patient outcomes. Also, identified through metabolomic studies, novel innovative metabolic markers such as steroid hormones, biogenic amines, members of the oxidative status, sphingo- and glycerophospholipids, and trimethylamine-N-oxide (TMAO) have shown promising results. Since many uncertainties remain in predicting mortality in these patients, further prospective and retrospective observational studies are needed to uncover metabolic pathways responsible for mortality associated with LRTI. Improved understanding of outcome-specific metabolite signatures in LRTIs may optimize patient management strategies, provide potential new targets for future individual therapy, and thereby improve patients’ chances for survival.

Simultaneous determination of phosphatidylcholine-derived quaternary ammonium compounds by a LC-MS/MS method in human blood plasma, serum and urine samples.

The determination of circulating trimethylamine-N-oxide (TMAO), choline, betaine, l-carnitine and O-acetyl-l-carnitine concentration in different human matrices is of great clinical interest. Recent results highlighted the prognostic value of TMAO and quaternary ammonium containing metabolites in the field of cardiovascular and kidney diseases. Herein, we report a method for the rapid and simultaneous measurement of closely related phosphatidylcholine-derived metabolites in three different biological matrices by stable isotope dilution assay. Plasma, serum and urine samples were simply deproteinized and separated by HILIC-chromatography. Detection and quantification were performed using LC-MS/MS with electrospray ionization in positive mode. For accuracy and precision, full calibration was performed covering more than the full reference range. Assay performance metrics include intra- and interday imprecision were below 10% for all analytes. To exclude matrix effects standard addition methods were applied for all matrices. It was shown that calibration standards and quality control prepared in water can be used instead of matrix-matched calibration and controls. The LC/MS/MS-based assay described in this article may improve future clinical studies evaluating TMAO and related substances as prognostic markers for cardiovascular risk and all-cause mortality in different patient populations.