Plasma free carnitine in severe trauma: Influence of the association with traumatic brain injury.

BACKGROUND: Metabolic response to severe trauma requires early nutritional resuscitation. Carnitine is essential for lipolysis, the energy source during this hypercatabolic phase. However l-carnitine is not present in nutritional replacement solutions. Furthermore, free carnitine depletion, defined as carnitine plasma level under 36µmol/L, was not adequately reported in adult patients with severe trauma. The aim of this study was to assess plasma free carnitine levels and factors of variation in severe trauma. METHOD: Our observational study concerned 38 trauma patients including 18 with traumatic brain injury (TBI). On the third day after trauma, plasma free carnitine concentration was determined (by enzymatic method) while patients received artificial nutrition. RESULTS: Low plasmatic free carnitine concentration was evidenced in 95% of the patients with a median value of 18µmol/L (11-47). Univariate analysis showed that mean arterial pressure, serum urea, CKD-EPI and patients with TBI were significantly associated with plasma free carnitine concentration less than 18µmol/L. Lower plasma free carnitine concentration was observed in the group of patients with TBI with 17.72µmol/L (11-36) versus 21.5µmol/L (11-47) for others patients (p=0.031). Logistic regression analysis showed that severe trauma with TBI and CKD-EPI above 94mL/min/1.73m2 appeared to be independent predictor of lower free carnitine plasmatic concentration (Goodness of fit=0.87 and AUC=0.89). CONCLUSION: Our observations support hypotheses that plasma free carnitine concentration is lowered in severe injured patients especially for TBI patients and patients with estimated GFR above 94mL/min/1.73m2.

A whole-body physiologically based pharmacokinetic (WB-PBPK) model of ciprofloxacin: a step towards predicting bacterial killing at sites of infection.

The purpose of this study was to develop a whole-body physiologically based pharmacokinetic (WB-PBPK) model for ciprofloxacin for ICU patients, based on only plasma concentration data. In a next step, tissue and organ concentration time profiles in patients were predicted using the developed model. The WB-PBPK model was built using a non-linear mixed effects approach based on data from 102 adult intensive care unit patients. Tissue to plasma distribution coefficients (Kp) were available from the literature and used as informative priors. The developed WB-PBPK model successfully characterized both the typical trends and variability of the available ciprofloxacin plasma concentration data. The WB-PBPK model was thereafter combined with a pharmacokinetic-pharmacodynamic (PKPD) model, developed based on in vitro time-kill data of ciprofloxacin and Escherichia coli to illustrate the potential of this type of approach to predict the time-course of bacterial killing at different sites of infection. The predicted unbound concentration-time profile in extracellular tissue was driving the bacterial killing in the PKPD model and the rate and extent of take-over of mutant bacteria in different tissues were explored. The bacterial killing was predicted to be most efficient in lung and kidney, which correspond well to ciprofloxacin's indications pneumonia and urinary tract infections. Furthermore, a function based on available information on bacterial killing by the immune system in vivo was incorporated. This work demonstrates the development and application of a WB-PBPK-PD model to compare killing of bacteria with different antibiotic susceptibility, of value for drug development and the optimal use of antibiotics .

Ciprofloxacin use in critically ill patients: pharmacokinetic and pharmacodynamic approaches.

The objective of this study was to evaluate the properties of ciprofloxacin in intensive care patients using a population approach. Seventy patients received ciprofloxacin. On Day 1, three to eight blood samples were taken over a 12-h period. Peak drug concentration (Cmax) and 24-h area under the concentration-time curve (AUC) were compared with the French breakpoint defining antibiotic susceptibility. A population pharmacokinetic modelling approach was then carried out. A two-compartment open model with a proportional error model best fitted the data. A relationship between the elimination constant rate and the Cockcroft creatinine clearance was found. Ciprofloxacin clearance was 13.6+/-5.8L/h, the volume of distribution was 62.0+/-10.7 L and the ciprofloxacin half-life was 3.7+/-1.8h. When the minimum inhibitory concentration (MIC) was equal to 1mg/L the inhibitory ratio (IR) was > or = 8 in only 10.8% of cases, and the AUC/MIC ratio (AUIC) was 42.0+/-36. In conclusion, this study highlights that the Cockcroft clearance significantly influences ciprofloxacin elimination. Target plasma concentrations for ciprofloxacin, the IR and AUIC were rarely reached with a standard dosing regimen. In critically ill patients, the observed pharmacokinetic variability is mainly responsible for the overly frequent low concentrations of ciprofloxacin, emphasising the need for therapeutic monitoring.

Acute copper sulphate poisoning: a case report and literature review.

Voluntary copper poisoning is a rare mode of suicide. We report a case of copper sulphate poisoning in a patient presenting delusions with mystic demands for purification. The initial gastrointestinal symptoms were followed by intravascular haemolysis and renal failure. The course was favourable after symptomatic treatment and specific copper chelation therapy. However, the pathogenesis is not fully understood and with the present state of knowledge, no one treatment can be said to be superior to another. The authors discuss the various treatments of this rare poisoning through a review of the available literature.

Avocado/soybean unsaponifiables increase aggrecan synthesis and reduce catabolic and proinflammatory mediator production by human osteoarthritic chondrocytes.

OBJECTIVE: To investigate the effects of avocado (A)/soybean (S) unsaponifiables on the metabolism of human osteoarthritic (OA) chondrocytes cultured in alginate beads over 12 days. METHODS: Enzymatically isolated OA chondrocytes were cultured in alginate beads in a well defined culture medium for 12 days, in the presence or not of 10-10 M interleukin 1beta (IL-1beta). DNA content was measured using a fluorometric method. Production of aggrecan (AGG), stromelysin-1 (MMP-3), tissue inhibitor of metalloproteinases-1 (TIMP-1), macrophage inflammatory protein-1beta (MIP-1beta), IL-6, and IL-8 were assayed by specific enzyme amplified sensitivity immunoassays. Prostaglandin (PG) E2 was measured by a specific radioimmunoassay and nitrite by a spectrophotometric method based on the Griess reaction. A commercial avocado and soybean mixture of unsaponifiables (A1S2) and each component separately were tested in a range of 0.625 to 40.0 micro g/ml. RESULTS: After 12 days' incubation, A1S2 increased AGG synthesis and accumulation in alginate beads in a dose and time dependent manner. A1S2 promoted the recovery of aggrecan synthesis after 3 days of IL-1beta treatment. A1S2 was a potent inhibitor of basal and IL-1beta stimulated MMP-3 production. The procedure also weakly reversed the inhibitory effect of IL-1beta on TIMP-1 production. A1S2 inhibited basal production of MIP-1beta, IL-6, IL-8, NO*, and PGE2 by OA chondrocytes and partially counteracted the stimulating effect of IL-1 on PGE2. Compared to avocado or soybean added separately, the mixture had a superior effect on NO* and IL-8 production. CONCLUSION: A1S2 stimulated aggrecan production and restored aggrecan production after IL-1beta treatment. In parallel, A1S2 decreased MMP-3 production and stimulated TIMP-1 production. These results suggest A1S2 could have structure-modifying effects in OA by inhibiting cartilage degradation and promoting cartilage repair.