Multi-Ratio Equilibrium Passive Sampling Method to Estimate Accessible and Pore Water Concentrations of Polycyclic Aromatic Hydrocarbons and Polychlorinated Biphenyls in Sediment

The freely dissolved concentration (C-w,C-0) in the pore water and the accessible (releasable) concentration in the sediment (C-as,C-0) are important parameters for risk assessment. These parameters were determined by equilibrating contaminated sediments and passive samplers using largely differing sampler-sediment ratios. This method is based on the principle that incubations at low sampler/sediment ratios yield the concentration in the pore water (minor depletion of the sediment phase) and incubations at high sampler/sediment ratios yield the accessible concentration in the sediment (maximum depletion of the sediment phase). It is shown that equilibration was faster in dense suspensions and at high sampler/sediment ratios when compared to low sampler/sediment ratios. An equilibrium distribution model was used to estimate C-w,C-0 and C-as,C-0 by nonlinear least-squares regression. The method was evaluated three sediments (harbor, estuarine, marine). Accessible concentrations of 13 PAHs were 2 (low K-ow) to 10 (high K-ow) times lower than the total concentrations (three sediments). By contrast, the accessible concentrations of 15 PCBs were about 1.2 times lower than the total concentrations and displayed no trend with K-ow (one sediment). Implications for risk assessment and considerations for application of multi-ratio equilibrium passive sampling with other sediments are discussed

Intravenous Lidocaine: Old-School Drug, New Purpose-Reduction of Intractable Pain in Patients with Chemotherapy Induced Peripheral Neuropathy

Background. Treatment of intractable pain due to chemotherapy induced peripheral neuropathy (CIPN) is a challenge. Intravenous (iv) lidocaine has shown to be a treatment option for neuropathic pain of different etiologies. Methods. Lidocaine (1.5 mg/kg in 10 minutes followed by 1.5 mg/kg/h over 5 hours) was administered in nine patients with CIPN, and analgesic effect was evaluated during infusion and after discharge. The immediate effect of lidocaine on pressure pain thresholds (PPT) and the extent of the stocking and glove distribution of sensory abnormalities (cold and pinprick) were assessed. Results. Lidocaine had a significant direct analgesic effect in 8 out of 9 patients (P = 0.01) with a pain intensity difference of >30%. Pain reduction persisted in 5 patients for an average of 23 days. Lidocaine did not influence mean PPT, but there was a tendency that the extent of sensory abnormalities decreased after lidocaine. Conclusion. Iv lidocaine has direct analgesic effect in CIPN with a moderate long-term effect and seems to influence the area of cold and pinprick perception. Additional research is needed, using a control group and larger sample sizes to confirm these results