Development and Validation of a High-Performance Liquid Chromatography-Ultraviolet Spectrometry Method for Ampicillin and its Application in Routine Therapeutic Drug Monitoring of Intensive Care Patients.

BACKGROUND: Ampicillin/sulbactam, a combination of a ß-lactam and ß-lactamase inhibitor, is widely used in clinical settings. However, therapeutic drug monitoring (TDM) of ampicillin is not commonly performed, particularly in intensive care units (ICUs). The purpose of this study was to develop and validate a rapid and cost-effective high-performance liquid chromatography (HPLC)-ultraviolet spectrometry method to quantify ampicillin in human serum and evaluate its clinical application in ICU patients. METHODS: Sample cleanup included a protein precipitation protocol, followed by chromatographic separation on a C18 reverse-phase HPLC column within 12.5 minutes using gradient elution of the mobile phase. The assay was validated according to the German Society of Toxicology and Forensic Chemistry criteria. Clinical applications involved the retrospective analysis of TDM data from ICU patients receiving continuous infusion of ampicillin/sulbactam, including the attainment of target ranges and individual predicted and observed pharmacokinetics. RESULTS: The method was robust, with linear relations between the peak area responses and drug concentrations in the range of 2-128 mg/L. The coefficient of variation for precision and the bias for accuracy (both interday and intraday) were less than 10%. Clinical application revealed variable pharmacokinetics of ampicillin in ICU patients (clearance of 0.5-31.2 L/h). TDM-guided dose adjustments achieved good therapeutic drug exposure, with 92.9% of the samples being within the optimal (16-32 mg/L) or quasioptimal (8-48 mg/L) range. CONCLUSIONS: This method provides a practical solution for the routine TDM of ampicillin, facilitating individualized dosing strategies to ensure adequate therapeutic drug exposure. Given its simplicity, cost-effectiveness, and clinical relevance, HPLC-ultraviolet spectrometry holds promise for broad implementation in hospital pharmacies and clinical laboratories.

Association of growth differentiation factor 15 with other key biomarkers, functional parameters and mortality in community-dwelling older adults.

BACKGROUND: Growth differentiation factor 15 (GDF-15) has been associated with many adverse age-related outcomes and other age-related disorders. The aim of the study was to investigate if baseline levels of GDF-15 are associated with total mortality in community living, older adults during eight years of follow-up after simultaneous consideration of key biomarkers and functional parameters. METHODS: prospective cohort study including 1,470 community-dwelling older adults aged 65 years or older. GDF-15 was measured by ElectroChemi-Lumisnescence Immunoassays (Roche, Mannheim, Germany). We used Cox-proportional hazards regression to estimate the association of GDF-15 levels with 8-year all-cause mortality. RESULTS: GDF-15 levels were independently of age and sex strongly associated with many biomarkers such as CRP, IL-6, NT-proBNP, hs-troponines as well as with lipids, metabolic and endocrine markers and kidney function (all P-values < 0.001). GDF-15 showed also a statistically significant correlation to gait speed, hand grip strength and walking duration. In addition, we found a consistent association between levels of GDF-15 and risk of subsequent all-cause mortality which persisted after additional adjustment for key markers of inflammation, cardiac function and damage, and physical function. The hazard ratio (HR) per unit increase of log-transformed GDF-15 was 1.72 (95% CI 1.35; 2.18). CONCLUSIONS: GDF-15 levels were not only strongly associated with many functional parameters and key biomarkers independently of age and sex, but also with 8-year all-cause mortality even after adjusting for gait speed, NT-proBNP and hs-TnT.

Distinct Dynamics of Stem and Progenitor Cells in Blood of Polytraumatized Patients.

Endogenously mobilized stem and progenitor cells (SPCs) or exogenously provided SPCs are thought to be beneficial for trauma therapy. However, still little is known about the synchronized dynamics of the number of SPCs in blood after severe injury and parameters like cytokine profiles that correlate with these numbers. We determined the number of hematopoietic stem cells, common myeloid progenitors, granulocyte-macrophage progenitors, and mesenchymal stem/stromal cells in peripheral blood (PB) 0 to 3, 8, 24, 48, and 120 h after polytrauma in individual patients (injury severity score ≥ 21). We found that the number of blood SPCs follows on average a synchronous, inverse bell-shaped distribution, with an increase at 0 to 3 h, followed by a strong decrease, with a nadir in SPC numbers in blood at 24 or 48 h. The change in numbers of SPCs in PB between 48 h and 120 h revealed two distinct patterns: Pattern 1 is characterized by an increase in the number of SPCs to a level higher than normal, pattern 2 is characterized by an almost absent increase in the number of SPCs compared to the nadir. Changes in the concentrations of the cytokines CK, MDC, IL-8, G-CSF Gro-α, VEGF, and MCP-1 correlated with changes in the number of SPCs in PB or were closely associated with Pattern 1 or Pattern 2. Our data provide novel rationale for investigations on the role of stem cell mobilization in polytraumatized patients and its likely positive impact on trauma outcome.

Recombinant streptavidin-C3bot for delivery of proteins into macrophages.

We demonstrated previously that monocytes and macrophages are target cells for the Rho-modifying Clostridium botulinum C3 ADP-ribosyltransferase. Here, we report the construction, expression and characterization of a recombinant streptavidin-C3 fusion protein which allows for delivery of biotin-labelled molecules into the cytosol of macrophages via enzymatically inactive C3bot1E174Q. The enzyme domain of diphtheria toxin was used as cargo to demonstrate proof of principle. This transport system could represent an attractive tool for experimental monocyte/macrophage pharmacology.