Journal:

Article Title: Improved Temporal Resolution for in Vivo Microdialysis by Using Segmented Flow

doi: 10.1021/ac800622s

Figure Lengend Snippet: (A) Illustration of microdialysis/segmented flow system used in this work. Arrows indicate direction of flow. Micrograph in inset illustrates plug generation at a tee junction. (Aqueous stream contains food dye for visualization.) Aqueous channels had a width of 125 μm and main channel with segmented flow had a width of 250 μm. (B) Dependence of plug volume on oil flow rate at different aqueous flow rates (Qw) for structure shown in Figure 1A. (C) Dependence of interval time between plugs on oil flow rate at Qw for structure shown in Figure 1A.

Article Snippet: This work suggests that improved membranes or sampling without membranes, such as direct 21 or push-pull sampling, 20 would be required to further improve the temporal resolution. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window caption a7 Simulation of response to step change in fluorescein concentration at a microdialysis probe using COMSOL. (A) The geometry of the dialysis probe was the same as those used experimentally i.e., 200 μm inner diameter, 220 μm outer diameter, side-by-side inlet and outlet capillaries and a 40 μm i.d. by 3.5 cm long exit capillary.

Techniques:

Journal:

Article Title: Improved Temporal Resolution for in Vivo Microdialysis by Using Segmented Flow

doi: 10.1021/ac800622s

Figure Lengend Snippet: Response obtained at both low and high sampling flow rate with microdialysis probes with different membrane lengths. (A) 2 mm probe at 200 nL/min; (B) 2 mm probe at 1 μL/min; (C) 1 mm probe at 200 nL/min; (D) 1 mm probe at 1 μL/min. Fluorescein concentration was changed from 2 μM to 5 μM at the probe surface. Cross-sectional flow rates were 1 μL/min for 200 nL/min sampling rate and were 4 μL/min for 1 μL/min sampling rate. Data traces are raw output from LIF detector and show detection of individual sample plugs. Temporal resolution, defined as the time during which signals increased from 10% to 90% of the maximum intensity, is marked on each graph. Chip conditions were the same as described in Figure 1.

Article Snippet: This work suggests that improved membranes or sampling without membranes, such as direct 21 or push-pull sampling, 20 would be required to further improve the temporal resolution. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window caption a7 Simulation of response to step change in fluorescein concentration at a microdialysis probe using COMSOL. (A) The geometry of the dialysis probe was the same as those used experimentally i.e., 200 μm inner diameter, 220 μm outer diameter, side-by-side inlet and outlet capillaries and a 40 μm i.d. by 3.5 cm long exit capillary.

Techniques: Sampling, Membrane, Concentration Assay

Journal:

Article Title: Improved Temporal Resolution for in Vivo Microdialysis by Using Segmented Flow

doi: 10.1021/ac800622s

Figure Lengend Snippet: Simulation of response to step change in fluorescein concentration at a microdialysis probe using COMSOL. (A) The geometry of the dialysis probe was the same as those used experimentally i.e., 200 μm inner diameter, 220 μm outer diameter, side-by-side inlet and outlet capillaries and a 40 μm i.d. by 3.5 cm long exit capillary. Curved arrow indicates direction of dialysis flow. The steady state concentration gradient for unit concentration outside the probe is shown over the geometry in this illustration. (B) The response shown is the concentration change at the outlet of the exit capillary following a step change from zero to unit concentration at time zero. The probe lengths and dialysis flow rates are given in the legend.

Article Snippet: This work suggests that improved membranes or sampling without membranes, such as direct 21 or push-pull sampling, 20 would be required to further improve the temporal resolution. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window caption a7 Simulation of response to step change in fluorescein concentration at a microdialysis probe using COMSOL. (A) The geometry of the dialysis probe was the same as those used experimentally i.e., 200 μm inner diameter, 220 μm outer diameter, side-by-side inlet and outlet capillaries and a 40 μm i.d. by 3.5 cm long exit capillary.

Techniques: Concentration Assay

Journal:

Article Title: Improved Temporal Resolution for in Vivo Microdialysis by Using Segmented Flow

doi: 10.1021/ac800622s

Figure Lengend Snippet: Glucose assay with segmented flow system. (A) Micrograph of microchannel network used for enzymatic assay within plugs. Food dye has been added to the Amplex® red and GOX/HRP streams for visualization. (B) Reaction scheme for the enzymatic assay. (C) LIF response when glucose concentration was changed at the probe from 0.2 to 1 mM. The inset shows an amplified view of the trace. Data are raw traces showing detection of individual plugs. (D) Calibration curve for glucose sampled by microdialysis and assayed using this system. Glucose concentrations are sampled concentrations.

Article Snippet: This work suggests that improved membranes or sampling without membranes, such as direct 21 or push-pull sampling, 20 would be required to further improve the temporal resolution. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window caption a7 Simulation of response to step change in fluorescein concentration at a microdialysis probe using COMSOL. (A) The geometry of the dialysis probe was the same as those used experimentally i.e., 200 μm inner diameter, 220 μm outer diameter, side-by-side inlet and outlet capillaries and a 40 μm i.d. by 3.5 cm long exit capillary.

Techniques: Glucose Assay, Enzymatic Assay, Concentration Assay, Amplification

Journal: CPT: Pharmacometrics & Systems Pharmacology

Article Title: Multiscale Design of Cell-Type–Specific Pharmacokinetic/Pharmacodynamic Models for Personalized Medicine: Application to Temozolomide in Brain Tumors

doi: 10.1038/psp.2014.9

Figure Lengend Snippet: TMZ PK in mice. ( a ) TMZ blood concentration–time profile. Solid line is the forcing function best fit. Open circles are the measured TMZ plasma concentrations from the microdialysis study. ( b–e ) TMZ interstitial ( b ) and intracellular ( c ), intracellular methylating cation ( d ), and DNA adducts ( e ) concentration–time profiles in normal brain (solid line) and brain tumor (dashed lines). Open circles ( b ) are TMZ normal brain concentrations from the microdialysis study. ( f ) TMZ concentrations in the whole normal brain and brain tumor after steady-state dosing regimen. Open circles are the experimental results in brain tumor-bearing mice; black diamonds are the model best fit. PK, pharmacokinetics; TMZ, temozolomide.

Article Snippet: On the day of and prior to TMZ administration, the dummy cannulas were replaced by microdialysis probes (MRB-1–5; Bioanalytical Systems, West Lafayetter, IN) and the probe TMZ recovery values were determined using the retrodialysis method as described previously with minor modifications.

Techniques: Concentration Assay, Clinical Proteomics, Drug discovery

Journal: CPT: Pharmacometrics & Systems Pharmacology

Article Title: Multiscale Design of Cell-Type–Specific Pharmacokinetic/Pharmacodynamic Models for Personalized Medicine: Application to Temozolomide in Brain Tumors

doi: 10.1038/psp.2014.9

Figure Lengend Snippet: TMZ PK in brain tumor patients. ( a ) TMZ blood concentration–time profile. Solid line is the forcing function best fit. Open circles are TMZ plasma concentration measurements in patients. ( b–e ) TMZ interstitial ( b ) and intracellular ( c ) concentration–time profiles in the normal brain (solid lines) and brain tumor (dashed lines). Blue color corresponds to the model calibrated with naive parameters, whereas black color represents the best-fit model with estimated parameters. In ( b ), open diamonds are TMZ normal brain concentrations from microdialysis measurements in patients, which are shown in greater details in the inset, together with TMZ normal brain interstitial concentration best-fit profile. ( f ) Global analysis of parameter sensitivity on drug efficacy in brain tumor (see Results and Methods). PK, pharmacokinetics; TMZ, temozolomide.

Article Snippet: On the day of and prior to TMZ administration, the dummy cannulas were replaced by microdialysis probes (MRB-1–5; Bioanalytical Systems, West Lafayetter, IN) and the probe TMZ recovery values were determined using the retrodialysis method as described previously with minor modifications.

Techniques: Concentration Assay, Clinical Proteomics, Drug discovery

Journal: CPT: Pharmacometrics & Systems Pharmacology

Article Title: Multiscale Design of Cell-Type–Specific Pharmacokinetic/Pharmacodynamic Models for Personalized Medicine: Application to Temozolomide in Brain Tumors

doi: 10.1038/psp.2014.9

Figure Lengend Snippet: A multiscale approach to design cell-type–specific PK-PD models for personalized medicine. The in vitro study is based on experimental drug investigations in solutions and in cell culture, which allow the design and calibration of a mathematical model describing the extracellular and intracellular drug PK-PD. Next, for the preclinical scale, the model of the interstitial and intracellular compartments is directly inferred from the in vitro study and parameters are either kept identical, scaled, or estimated utilizing whole animal or tissue-based investigations that in our case included two separate studies: normal brain microdialysis and brain tumor orthotopic studies. This step allows the design and calibration of a whole-body or tissue model that designate specific tissues and cells of interest. For humans, the whole-body model or specific tissue structure remains and parameters are either kept identical, scaled from the preclinical study, or estimated from clinical data in order to compute an average population parameter set. Finally, the human model is partially re-parameterized from available data on the individual patient and utilized in optimization procedures, which provide personalized drug combinations and administration schemes. PD, pharmacodynamics; PK, pharmacokinetics.

Article Snippet: On the day of and prior to TMZ administration, the dummy cannulas were replaced by microdialysis probes (MRB-1–5; Bioanalytical Systems, West Lafayetter, IN) and the probe TMZ recovery values were determined using the retrodialysis method as described previously with minor modifications.

Techniques: In Vitro, Cell Culture, Drug discovery

Journal: The journal of trauma and acute care surgery

Article Title: Lung Protective Ventilation (ARDSNet) versus APRV: Ventilatory Management in a Combined Model of Acute Lung and Brain Injury

doi: 10.1097/TA.0000000000000518

Figure Lengend Snippet: Baseline (Pre-Injury and Pre-Randomization) Characteristics on Pressure Support (N=22)

Article Snippet: A CMA 20 Elite (14mm shaft length, 10mm membrane length, 20,000 Dalton porosity) cerebral microdialysis probe (CMA, A Harvard Apparatus Company, Holliston, MA, USA) was placed through this opening and directly into cerebral tissue.

Techniques:

Journal: The journal of trauma and acute care surgery

Article Title: Lung Protective Ventilation (ARDSNet) versus APRV: Ventilatory Management in a Combined Model of Acute Lung and Brain Injury

doi: 10.1097/TA.0000000000000518

Figure Lengend Snippet: Cerebral Microdialysis Biomarkers Following Lung and Brain Injury

Article Snippet: A CMA 20 Elite (14mm shaft length, 10mm membrane length, 20,000 Dalton porosity) cerebral microdialysis probe (CMA, A Harvard Apparatus Company, Holliston, MA, USA) was placed through this opening and directly into cerebral tissue.

Techniques: Significance Assay