The intravascular microdialysis method is based on a new and innovative technology, which involves a small compartment located between a catheter body and a covering microdialysis membrane. By perfusing this compartment, a dialysate fluid is produced wherein the concentrations of glucose and lactate are theoretically equal to those in the surrounding tissue, i.e. the bloodstream as the catheter is placed in a central vein. In Study I, the intravascular microdialysis concept was applied to a single- lumen catheter. The dialysate fluid was collected and intermittently analyzed in a separate dialysate analyzer for glucose and lactate concentrations and compared to blood samples. This study verified the microdialysis concept as an efficient clinical method for measuring blood glucose and lactate levels. In Study II, the outlet of the compartment of the microdialysis catheter was directly connected to a recently developed sensor, continuously analyzing glucose and lactate concentrations of the ...

Due to the constant perfusion of the microdialysis probe with fresh perfusate, a total equilibrium cannot be established.[1] This results in dialysate concentrations that are lower than those measured at the distant sampling site. In order to correlate concentrations measured in the dialysate with those present at the distant sampling site, a calibration factor (recovery) is needed. The recovery can be determined at steady-state using the constant rate of analyte exchange across the microdialysis membrane. The rate at which an analyte is exchanged across the semipermeable membrane is generally expressed as the analytes extraction efficiency. The extraction efficiency is defined as the ratio between the loss/gain of analyte during its passage through the probe (Cin−Cout) and the difference in concentration between perfusate and distant sampling site (Cin−Csample). In theory, the extraction efficiency of a microdialysis probe can be determined by: 1) changing the drug concentrations while ...

TY - JOUR. T1 - Release and metabolism of 5-hydroxytryptamine in the cat spinal cord examined with microdialysis. AU - Sorkin, L. S.. AU - Hughes, M. G.. AU - Liu, D.. AU - Willis, W. D.. AU - McAdoo, D. J.. PY - 1991. Y1 - 1991. N2 - The primary objective of this work was to investigate how in vivo administration of depolarizing agents increases extracellular concentrations of 5-hydroxytryptamine (5-HT) and simultaneously decreases levels of its chief metabolite 5-hydroxyindole-3-acetic acid (5-HIAA). To this end the effects of a number of agents on extracellular levels of 5-HT and 5-HIAA in cat spinal cord were determined by microdialysis and high-pressure liquid chromatography with electrochemical detection. The semipermeable portion of the dialysis probe was centered in the dorsal horn. Artificial cerebrospinal fluid containing elevated K+ or drugs was introduced into the dorsal horn via the dialysis probe. Increases in recovered 5-HT were assumed to reflect increased levels in the ...

Principal Investigator：SHIMAMURA Yohnosuke, Project Period (FY)：1990 - 1992, Research Category：Grant-in-Aid for General Scientific Research (C), Research Field：内分泌・代謝学

Prolyl oligopeptidase (PREP, EC 3.4.21.26) inhibitors have potential as cognition enhancers, but the mechanism of action behind the cognitive effects remains unclear. Since acetylcholine (ACh) and dopamine (DA) are known to be associated with the regulation of cognitive processes, we investigated the effects of two PREP inhibitors on the extracellular levels of ACh and DA in the rat striatum using in vivo microdialysis. KYP-2047 and JTP-4819 were administered either as a single systemic dose (50 μmol/kg∼17 mg/kg i.p.) or directly into the striatum by retrodialysis via the microdialysis probe (12.5, 37.5 or 125 μM at 1.5 μl/min for 60 min). PREP inhibitors had no significant effect on striatal DA levels after systemic administration. JTP-4819 significantly decreased ACh levels both after systemic (by ∼25%) and intrastriatal (by ∼3050%) administration. KYP-2047 decreased ACh levels only after intrastriatal administration by retrodialysis (by ∼4050%) when higher drug levels were reached, ...

Antiepileptic drug (AED) resistance affects one third of patients with epilepsy and is associated with significant disability. Brain microdialysis studies on the epileptogenic hippocampus of patients with medication refractory epilepsy have identified elevations in extracellular glutamate, the primary brain excitatory neurotransmitter, both acutely during seizures and chronically during the interictal periods. Whether extracellular glutamate, along with the metabolites glutamine and the inhibitory neurotransmitter GABA (gamma-aminobutyric acid), are elevated in other cortical regions is unknown. In addition, the effect of the administration of AEDs on the extracellular levels of these neurochemicals in patients with medication-refractory epilepsy is also unknown. Microdialysis samples were obtained from probes coupled to the EEG depth electrodes and implanted in the cortex and hippocampus of 81 awake patients with medication-refractory epilepsy undergoing intracranial electroencephalographic (EEG)

Background. Cytokines, such as the interleukins (IL1β, IL2, IL6) and tumor necrosis factor (TNF) can modulate myocardial structure and function with ischemia/reperfusion (I/R) but dynamic assessment of these biological molecules within the human myocardial interstitium with I/R has not been performed, and the inter-relationship to matrix metalloproteinases activity (MMPact) remains unexplored. Accordingly, a fluorogenic microdialysis method was used to simultaneously measure myocardial interstitial cytokine levels and MMPact in patients during and following I/R.. Methods. MMPact was measured in patients (n=13) undergoing cardio-pulmonary bypass (CPB) at baseline, during myocardial arrest and CPB (on-CPB), and immediately following reperfusion and separation from CPB (post-CPB) by a validated in-line microdialysis fluorescent detection system. Myocardial interstitial fluid was subjected to cytokine analysis by high sensitivity multiplex suspension array.. Results. Interstitial MMPact increased ...

This study reveals the major contribution of ANP in the stimulation of lipid mobilization from SCAT during repeated bouts of endurance exercise. Numerous works have mentioned the role of epinephrine and insulin in this process, but the role of ANP has never been evoked. Sequential 45-min exercise bouts separated by a 60-min rest were used to promote SNS activation and ANP release. On the basis of the use of the microdialysis technique and local selective blockade of α2- and β1/2-ARs within SCAT, we showed that more than 50% of the nonadrenergic lipolysis observed during a repeated bout of exercise is ANP dependent.. Catecholamines released under SNS activation during exercise were long considered to be the major agents controlling lipid mobilization from adipose tissue in humans (16, 34). We recently demonstrated (27) that NP act in a new pathway to control human fat cell lipolysis in vitro or when administered intravenously. Using the microdialysis method, we previously demonstrated that ...

INTRODUCTION: Accurate assessment of muscle insulin sensitivity requires measurement of insulin concentration in interstitial fluid (ISF), but has proved difficult. We aimed to optimise measurement of ISF insulin concentrations in rat muscles in vivo using microdialysis. METHODS: Factorial experimental design experiments were performed in vitro to determine optimal conditions for insulin recovery with microdialysis probes. These conditions were tested in vivo, adjusted appropriately and used in lean and obese Zucker rats to compare ISF insulin concentrations basally and during hyperinsulinaemic-euglycaemic (HE) clamp. RESULTS: Optimal conditions in vivo were: a 100kDa microdialysis probe inserted in muscle, perfused with 1% BSA, 1.5mM glucose in 0.9% sodium chloride at 1μl/min. Samples were collected into siliconised glass microvials. As a reference for insulin, we established a protocol of inulin infusion, beginning at -80min and reaching equilibrium within 60min. HE clamp, beginning at 0min, ...

In this thesis, fluid characteristics and sampling efficiency of high molecular weight cut-off microdialysis are presented, with the aim of improving the understanding of microdialysis sampling mechanisms and its performance regarding extraction efficiency of biological fluid and biomarkers.. Microdialysis is a well-established clinical sampling tool for monitoring small biomarkers such as lactate and glucose. In recent years, interest has raised in using high molecular weight cut-off microdialysis to sample macro molecules such as neuropeptides, cytokines and proteins. However, with the increase of the membrane pore size, high molecular weight cut-off microdialysis exhibits drawbacks such like unstable catheter performance, imbalanced fluid recovery, low and unstable molecule extraction efficiency, etc. But still, the fluid characteristics of high molecular weight cut-off microdialysis is rarely studied, and the clinical or in vitro molecule sampling efficiency from recent studies vary from ...

Using whole-cell patch-clamp recording in brain slices17-19⇓⇓ and in vivo microdialysis methods,20 the major target neurons of A2A receptor-mediated modulation were identified as GABAergic striatopallidal medium spiny neurons (MSNs).1 These striatal projection neurons may receive A2A receptor-mediated regulation in two distinct modes. The main loci of this adenosine A2A receptor-mediated dual modulation in the striatopallidal system1,21⇓ are as follows. 1) In the striatum, A2A receptors control excitability of the projection neurons through the intrastriatal GABAergic feedback and feed-forward inhibition network.17 Major elements regulating the excitability of MSNs in the striatum are GABAergic inputs, which come from axon collaterals of the MSNs themselves and GABAergic interneurons. A2A receptors on the axon terminals of these GABAergic neurons suppress GABA release, resulting in an increase in MSN excitability via relief of intrastriatal GABAergic inhibitory inputs onto the MSNs. This ...

Deep brain stimulation (DBS) has been established as an effective treatment for Parkinsons disease and other movement disor- ders. The stimulation is currently administered using tetrode-macroelectrodes that target the subthalamic nucleus (STN). This often leads to side effects which bias the surrounding ar- eas, e.g. the speech centre. Targeting a spe- cific brain region can better be achieved with micro-stimulation electrodes with directed elec- trical field distribution. Experimental studies showed the effectiveness of microelectrode DBS by comparing neurotransmitter outflow before and after the stimulation. The neurotransmit- ter outflow in close proximity to the stimulation is hereby measured by means of microdialysis. To establish ideal distances and stimulation strength, the electric potential around the stim- ulation electrode and microdialysis membrane were modelled using comsol Multiphysics.. ...

TY - JOUR. T1 - The diagnostic accuracy of brain microdialysis during surgery: a qualitative systematic review. AU - Bossers, S.M.. AU - de Boer, R.D.H.. AU - Boer, C.. AU - Peerdeman, S.M.. PY - 2013. Y1 - 2013. U2 - 10.1007/s00701-012-1582-z. DO - 10.1007/s00701-012-1582-z. M3 - Article. C2 - 23275069. VL - 155. SP - 345. EP - 353. JO - Acta Neurochirurgica. JF - Acta Neurochirurgica. SN - 0001-6268. IS - 2. ER - ...

Abstract: Microdialysis is a minimally invasive technique often paired with laser Doppler flowmetry to examine cutaneous microvascular function, yet presents with several challenges, including incompatibility with perfusion of highly lipophilic compounds. The present study addresses this methodological concern, with an emphasis on the independent effects of commonly used vehicle dialysis solutions to improve solubility of pharmacological agents with otherwise low aqueous solubility. Four microdialysis fibers were placed in the ventral forearm of eight subjects (4 men, 4 women; 25 ± 1 yr) with sites randomized to serve as 1) control (lactated Ringers), 2) Sodium carbonate- bicarbonate buffer administered at physiological pH [SCB-HCl; pH 7.4, achieved via addition of hydrochloric acid (HCl)], 3) 0.02% ethanol, and 4) 2% dimethyl sulfoxide (DMSO). After baseline (34°C), vehicle solutions were administered throughout a standardized local heating protocol to 42°C. Laser Doppler flowmetry provided ...

Object. Clinical microdialysis enables monitoring of the cerebral extracellular chemistry of neurosurgical patients. Introduction of the technique into different hospitals neurosurgical units has resulted in variations in the method of application. There are several variables to be considered, including length of the catheter membrane, type of perfusion fluid, flow rate of perfusion fluid, and on-line compared with delayed analysis of samples. The objects of this study were as follows: 1) to determine the effects of varying catheter characteristics on substance concentration; 2) to determine the relative recovery and true extracellular concentration by varying the flow rate and extrapolating to zero flow; and 3) to compare substance concentration obtained using a bedside enzyme analyzer with that of off-line high-performance liquid chromatography (HPLC).. Methods. A specially designed bolt was used to conduct two adjacent microdialysis catheters into the frontal cortex of patients with head ...

Object. Clinical microdialysis enables monitoring of the cerebral extracellular chemistry of neurosurgical patients. Introduction of the technique into different hospitals neurosurgical units has resulted in variations in the method of application. There are several variables to be considered, including length of the catheter membrane, type of perfusion fluid, flow rate of perfusion fluid, and on-line compared with delayed analysis of samples. The objects of this study were as follows: 1) to determine the effects of varying catheter characteristics on substance concentration; 2) to determine the relative recovery and true extracellular concentration by varying the flow rate and extrapolating to zero flow; and 3) to compare substance concentration obtained using a bedside enzyme analyzer with that of off-line high-performance liquid chromatography (HPLC).. Methods. A specially designed bolt was used to conduct two adjacent microdialysis catheters into the frontal cortex of patients with head ...

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Int J Antimicrob Agents. 2013 Mar;41(3):229-35. doi: 10.1016/j.ijantimicag.2012.10.020. Epub 2013 Jan 6. Research Support, Non-U.S. Govt

Over the last years, a number of systems for continuous subcutaneous glucose monitoring have been marketed and are routinely used in patients with diabetes to obtain more detailed information about 24-hour glucose profiles.. In the hospital, numerous factors influencing glycemic control and possibly leading to glucose excursions out of the desired range exist, e.g. interventions for which the patient has to remain fasting or medications such as corticosteroids or vasopressors. A reliable continuous glucose signal could help to observe levels of glycaemia not only at defined time-points but continuously, making it possible for physicians and nursing staff to better adjust antihyperglycemic therapy and to react before the patient is exposed to severe hypo- or hyperglycaemia.. In the hospital setting, vascular access is granted in the majority of patients and could as well be used as an alternative site for continuous glucose monitoring.. The aim of the present study is to assess accuracy of the ...

The analysis of low abundant biological molecules is often challenging due to their chemical properties, low concentration and limited sample volumes. Neuropeptides are one group of molecules that fits these criteria. Neuropeptides also play an important role in biological functions, which makes them extra interesting to analyze. A classic chemical analysis involves sampling, sample preparation, separation and detection. In this thesis, an enhanced solid supported microdialysis method was developed and used as a combined sampling- and preparation technique. In general, significantly increased extraction efficiency was obtained for all studied peptides. To be able to control the small sample volumes and to minimize the loss of neuropeptides because of unwanted adsorption onto surfaces, the subsequent analysis steps were miniaturized to a micro total analysis system (µ-TAS), which allowed sample pre-treatment, injection, separation, manipulation and detection.. In order to incorporate these ...

A catheter for insertion into a blood vessel of a living being, which includes an elongated catheter body and membrane defining a dialysis chamber; a first channel provided for delivery of dialysis liquid to the dialysis chamber and a second channel provided for the discharge of dialysis liquid from the dialysis chamber, wherein the dialysis chamber comprises a plurality of tubular members, each having an inlet end and an outlet end, all the inlet ends being connected to the first channel and all the outlet ends being connected to the second channel.

Objective The aim of this study was to investigate whether the effects on local blood flow and metabolic changes observed in the skin after an endogenous systemic increase in insulin are mediated by the endothelial nitric oxide pathway, by administering the nitric oxide synthase inhibitor N-G-monomethyl l-arginine using microdialysis. Methods Microdialysis catheters, perfused with N-G-monomethyl l-arginine and with a control solution, were inserted intracutaneously in 12 human subjects, who received an oral glucose load to induce a systemic hyperinsulinemia. During microdialysis, the local blood flow was measured by urea clearance and by laser speckle contrast imaging, and glucose metabolites were measured. Results After oral glucose intake, microvascular blood flow and glucose metabolism were both significantly suppressed in the N-G-monomethyl l-arginine catheter compared to the control catheter (urea clearance: P amp;lt; .006, glucose dialysate concentration: P amp;lt; .035). No significant ...

The technique of microdialysis enables sampling and collecting of small‐molecular‐weight substances from the interstitial space

PHARMACOGENETICS USING MICROARRAYS. Microdialysis in rodents using certified GMO animal facility. Quantitative analysis of CNS biomarkers (LC-MS/MS, LC-MS QTOF, LC-UV, LC-ECD, NMR, qPCR, microarray). Routine HPLC-MS/MS analysis of neurotransmitters (dopamine, DOPAC, HVA, 3-MT, serotonin, 5-HIAA, norepinephrine, GABA, glutamate from microdialysis sample or brain tissue) and ROS biomarkers (leukotriens, prostaglandins, aldehydes). ...

71 High Cut Off Microdialysis Bolt Catheter - unique new brain Microdialysis catheter with High cut off membrane for bolt implantation ...

Reliable, Flexible and Affordable. Microdialysis probes, instruments and accessories. In-house developed applications and user publications for reference.

CMA offers a complete range of industry-standard microdialysis probes and guides for todays research applications in drug development, neuroscience, physiology, tissue engineering, cancer research, and other emerging areas.

To test the hypothesis that inflammatory pain could dysregulate the function of the mesolimbic dopaminergic pathway, we first conducted in vivo microdialysis analyses to measure heroin-evoked DA release in the NAc core in the presence of inflammatory pain (Fig. 1). Although several reports have investigated the role of the DA increase in NAc shell versus NAc core in drug-induced motivated behaviors (Everitt and Robbins, 2005), we elected to focus on the NAc core given its role in instrumental action according to the value of the predicted outcome and motivated behavior (Di Chiara, 2002; Saddoris et al., 2013). Forty-eight hours following the administration of CFA or saline (control) in the rat hindpaw (n = 5 or 6 per group), a microdialysis probe targeting the NAc core was inserted, and extracellular DA content in the dialysates was monitored every 15 min. Once a stable baseline for DA was achieved (,10% variation in three consecutive samples), one of two heroin doses (75 or 150 μg/kg) was ...

It has previously been shown that Wortmannin, a phosphatidylinositol 3-kinase inhibitor, inhibits glucose transport activated by insulin but not by ischemia, suggesting the importance of an activating mechanism that bypasses the insulin signal. To evaluate the relevance of this insulin-independent pathway in insulin-resistant subjects, the ability of ischemia to stimulate glucose uptake was investigated in 9 patients with type 2 diabetes and in 9 healthy control subjects (fasting glucose level 9.4 +/- 0.8 vs. 5.1 +/- 0.1 mmol/l, P , 0.001, in type 2 diabetic patients and control subjects, respectively; fasting insulin level insulin 8.1 +/- 2.6 vs. 4.5 +/-0.7 mU/l, P , 0.05, respectively) matched for sex, age, and BMI. Arterial plasma and interstitial concentrations of glucose and lactate (measured by subcutaneous and muscle microdialysis) were recorded in the forearm before, during, and after ischemia induced locally for 20 min. During ischemia, the muscle interstitial glucose concentration ...

These results show that local perfusion with NMDA by retrodialysis produces a sustained increase in dialysate Cho. This effect of NMDA exhibits marked brain regional differences (Fig. 6 B). The NMDA-evoked increase in dialysate Cho precedes delayed excitotoxic cholinergic cell death and is blocked with AP-5, a competitive NMDA receptor antagonist. Interestingly, when NMDA was perfused for a short period of time (30 min), Cho levels remained significantly increased for at least 2 hr after discontinuation of NMDA perfusion (Fig.1 B).. Perfusion with a Ca2+-free medium or with a Ca2+-free medium in the presence of 5 mmEGTA completely blocked the NMDA-evoked increase in dialysate Cho, indicating that this effect is dependent on the extracellular concentration of calcium (Fig. 4). The fact that a strong depolarizing stimulus (i.e., 100 mm KCl), which is able to induce a sixfold increase in extracellular Ach (reflecting activation of voltage-dependent calcium inflow) and does not modify extracellular ...

Principal Investigator：ABE Youichi, Project Period (FY)：1995 - 1996, Research Category：Grant-in-Aid for Scientific Research (A), Section：試験, Research Field：応用薬理学・医療系薬学

A one-use, disposable device for use by soldiers in the field is being developed to measure glucose, glutamine and lactate (USAMRMC-funded).. A continuous version of this device is also being developed for diabetes care. The optoelectronics of the sensor and the microfluidics for the sample cells are being optimized. Preliminary evaluation in comparison to commercially available glucose meters is ongoing. Application to monitoring nutrients in cell culture through a microdialysis sampling procedure is underway.. ...

Förster, Y., Schmidt, J. R., Wissenbach, D. K., Pfeiffer, S. E. M., Baumann, S., Hofbauer, L. C., Bergen, M. von, Kalkhof, S., and Rammelt, S., Microdialysis Sampling from Wound Fluids Enables Quantitative Assessment of Cytokines, Proteins, and Metabolites Reveals Bone Defect-Specific Molecular Profiles, PloS one, V. 11, No. 7, 2016, e0159580.. Hsu, M. J., Kratochvil, I., Winkler, S., Hempel, M., Kühne, H., Kalkhof, S., Baumann, S., Schubert, K., Bergen, M., and Christ, B., Mesenchymale Stromalzellen begünstigen den Lipidabbau in isolierten Hepatozyten, Z Gastroenterol, V. 56, No. 08, 2018, e252-e253.. Kalkhof, S., Schildbach, S., Blumert, C., Horn, F., Bergen, M. von, and Labudde, D., PIPINO: A Software Package to Facilitate the Identification of Protein-Protein Interactions from Affinity Purification Mass Spectrometry Data, BioMed research international, V. 2016, 2016, p. 2891918.. Kratochvil, I., Hofmann, T., Rother, S., Schlichting, R., Moretti, R., Scharnweber, D., Hintze, V., ...

M Dialysis AB develops and markets clinical microdialysis solutions for advanced clinical research and general intensive care usage. Our microdialysis solutions are used across the globe by caregivers and researchers for improved health care.. M Dialysis AB is a Swedish medical device and research company that is an offshoot from CMA Microdialysis AB that was founded in 1984.. M Dialysiss unique and market leading solutions are developed, produced and sold to clinicians and researchers to enable optimized patient care and accelerated drug development. The complete line of microdialysis instruments, consumables and computer software are used globally by universities, hospitals and pharmaceutical companies as unique tools for in vivo sampling and monitoring of organs and tissues.. ...

TY - JOUR. T1 - Effects of obesity and exercise on the glucose metabolism of the rat in vivo. A study with the microdialysis techique. AU - Fuchi, T.. AU - Iwaoka, K.. AU - Higuchi, Mitsuru. PY - 1991. Y1 - 1991. UR - http://www.scopus.com/inward/record.url?scp=0025895912&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=0025895912&partnerID=8YFLogxK. M3 - Article. AN - SCOPUS:0025895912. SP - 140. EP - 144. JO - Bulletin of the Physical Fitness Research Institute. JF - Bulletin of the Physical Fitness Research Institute. SN - 0389-9071. IS - 77. ER - ...

Cerebral oxygen and microdialysis monitoring during aneurysm surgery: effects of blood pressure, cerebrospinal fluid drainage, and temporary clipping on infarct

Apart from conventional microdialysis that sample small molecular weight analytes, Charles River offers a push-pull method to sample high molecular weight analytes.

Adequate drug penetration to a site of infection is absolutely imperative to ensure sufficient antimicrobial treatment. Microdialysis is a minimally invasive, versatile technique, which can be used...

Zamboni has been involved in translational studies of anticancer agents for several years. His research interests focus on the application of pharmacokinetic, pharmacodynamic, and pharmacogenetic principles in the optimization of the chemotherapeutic treatment of cancer. Information obtained from preclinical and clinical translational studies can greatly add to the understanding of the pharmacology of anticancer agents; permit individualization of chemotherapeutic treatment based on pharmacokinetic, pharmacodynamic, and pharmacogenetic principles; and allow for the rational design of therapeutic regimens.. A second focus of his research is on the developments of nanosomal and nanoparticle anticancer agents and evaluating the relationship between the disposition f the s agents and the reticuloendothelial system. As part of these studies, he has used microdialysis to evaluate the tumor extracellular fluid disposition of anticancer agents and factors affecting the delivery and removal of anticancer ...

The technique of in vivo microdialysis has been used most frequently with larger species to measure extracellular levels of neurotransmitters but only recently has been adapted to mice because this species is being used to elucidate the genetic regulation of elements involved in neurotransmission. The baseline values for extracellular 5-HT measured in the mouse striatum were similar to those we have previously obtained from studies in rats (Kirby et al., 1997). In this study, we pharmacologically characterized the activity of two novel 5-HT receptor agonists in the mouse with in vivo microdialysis: the selective 5-HT1A receptor agonist 8-OH-PIPAT and the selective 5-HT1B/1D receptor agonist CP 94,253. This is the first report for 8-OH-PIPAT as a drug that appears to be a potent and efficacious agonist at the 5-HT1A receptor in vivo in mice and for CP 94,253 as a drug that activates the 5-HT1B terminal autoreceptor on systemic administration. The response to these drugs effects was measured in ...

A homogenous fluorescence dual-probe assay containing 2-N-(pyren-1-ylmethyl)-2-amino-LNA (locked nucleic acid) building blocks has been developed for effective mismatch-sensitive nucleic acid detection. The pyrene units, which are connected to the rigid bicyclic furanose derivative of 2-amino-LNA through a short linker, are positioned at the 3 and 5 ends of a dual-probe ...

MDC Repository is powered by EPrints 3 which is developed by the School of Electronics and Computer Science at the University of Southampton ...

Fractions cooled down to +6 °C Holds up to 64 sealed vials Fractions from 1-2000µL The CMA 470 Refrigerated Fraction Collector is especially designed to collect minute

You are currently visiting Medline.com in Internet Explorer 8 which is not supported. Please upgrade your browser or switch to a supported browser. For a list of supported browsers visit: https://www.medline.com/help/tech-support/. ...

The flow from a high-speed rotor in a rotor-first arrangement has been measured using a dual-probe, digital sampling (DPDS) technique. The flow field was found...

teaching kits for introduction to fatty acids, lipids and membranes, electroelution of DNA, RNA or protein, microdialysis, protein labeling and cross-linking, and RNA isolation

Microdialysis is a minimally invasive sampling technique that can be used to continuously monitor drug concentrations in the ECF of tissues that are accessible to microdialysis probe placement. The free drug concentration at the site of drug action in tissues is a critical determinant of the intensity of the drugs effect, and therefore monitoring tissue free drug concentration may be more informative than monitoring plasma drug concentrations.. We compared microdialysis sampling from blood and tissues to conventional sampling methods in a nonhuman primate model at steady state during a continuous infusion of zidovudine and after a bolus dose of zidovudine. The pharmacology of this nucleoside analog has been previously characterized in our animal model and the CSF penetration was 0.21 (Klecker et al., 1987; Collins et al., 1988; Balis et al., 1989). Zidovudine (mol. wt., 267) is well tolerated, lipophilic, and minimally protein bound, and a sensitive and specific assay for its detection and ...

Implantation of Microdialysis Guide Cannulae and Probe Insertions in the Hippocampus. Seven days before being used in microdialysis experiments, rats were anesthetized with a mixture of chloral hydrate and pentobarbital (170 and 36 mg/kg, respectively, in 30% propylene glycol and 14% ethanol), placed in a stereotaxic apparatus, and implanted unilaterally with guide cannulae (Bioanalytical Systems, Inc., West Lafayette, IN) in the hippocampus (coordinates: anteroposterior, -5.2; mediolateral, 5.2; dorsoventral, -3.8) according to the stereotaxic atlas of Paxinos and Watson (1998). Twenty-four hours before testing, a 4-mm concentric microdialysis probe (BAS Bioanalytical Systems, West Lafayette, IN) was inserted through the guide cannula.. Likewise, for mice, 2-mm microdialysis probes (CMA/Microdialysis, Solna, Sweden) were implanted unilaterally in the hippocampus (mediolateral, +3.1; anteroposterior, -3.3; dorsoventral, -4.2, based on the stereotaxic atlas of Franklin and Paxinos, 1997) under ...

TY - JOUR. T1 - Consequences of changes in BDNF levels on serotonin neurotransmission, 5-HT transporter expression and function. T2 - Studies in adult mice hippocampus. AU - Deltheil, Thierry. AU - Guiard, Bruno P.. AU - Guilloux, Jean Philippe. AU - Nicolas, Lorelei. AU - Deloménie, Claudine. AU - Repérant, Christelle. AU - Maitre, Erwan Le. AU - Leroux-Nicollet, Isabelle. AU - Benmansour, Saloua. AU - Coudoré, François. AU - David, Denis J.. AU - Gardier, Alain M.. PY - 2008/8/1. Y1 - 2008/8/1. N2 - In vivo intracerebral microdialysis is an important neurochemical technique that has been applied extensively in genetic and pharmacological studies aimed at investigating the relationship between neurotransmitters. Among the main interests of microdialysis application is the infusion of drugs through the microdialysis probe (reverse dialysis) in awake, freely moving animals. As an example of the relevance of intracerebral microdialysis, this review will focus on our recent neurochemical ...

Microsyringes are available in 1, 2.5, 5 and 10 mL sizes. These glass syringes have a 60 mm piston stroke. Syringe Needles are pretreated to reduce degradation of labile molecules, such as catecholamines and their metabolites during a microdialysis experiment. |br/| |br/| The Syringe Clip enables the withdrawal of liquids when using either the CMA 400 or the CMA 402 Syringe Pumps. The clip fastens the syringe plunger to the carriage of the pump. |br/| |br/| The Micro T is a three-way connector. Connected to the syringes in the CMA 402 Syringe Pump and a Microdialysis probe, two different perfusion fluids can be combined, even gradually, without introducing air bubbles into the system.

Dive into the research topics of Characterization of dopamine release in the rat medial prefrontal cortex as assessed by in vivo microdialysis: Comparison to the striatum. Together they form a unique fingerprint. ...

l-glutamate (Glu) is the main excitatory neurotransmitter in the central nervous system (CNS) and is associated with motor behavior and sensory perception. While microdialysis methods have been used to record tonic levels of Glu, little is known about the more rapid changes in Glu signals that may be observed in awake rats. We have reported acute recording methods using enzyme-based microelectrode arrays (MEA) with fast response time and low detection levels of Glu in anesthetized animals with minimal interference. The current paper concerns modification of the MEA design to allow for reliable measures in the brain of conscious rats. In this study, we characterized the effects of chronic implantation of the MEA into the brains of rats. We were capable of measuring Glu levels for 7 days without loss of sensitivity. We performed studies of tail-pinch induced stress, which caused a robust biphasic increase in Glu. Histological data show chronic implantation of the MEAs caused minimal injury to the ...

The mechanism behind hyperemia in skeletal muscle during insulin-induced hypoglycemia was investigated in 42 anesthetized male Wistar rats using the microdialysis ethanol technique of monitoring nutritive blood flow. Microdialysis probes were inserted bilaterally into the gastrocnemius muscle and perfused with a modified Krebs-Henseleit buffer containing 20 mmol/l ethanol and one or more of the following compounds: propranolol (10−6 molA), phentolamine (10−6 mol/1), and calyculin A (1.0 (xmol/1). Muscle blood flow increased, as indicated by a decrease in the ethanol outflow:inflow ratio (P , 0.001, n = 6), during hypoglycemia induced by a bolus intravenous infusion of insulin (680 mU/kg body wt). This increase was not present during normoglycemia or during hypoglycemia and local (β-adrenergic blockade via propranolol. However, the hyperemic response was potentiated during hypoglycemia and local β-adrenergic blockade via phentolamine. A normal hyperemic response to hypoglycemia was detected ...

Disturbances in serotonergic neurotransmission have been suggested to be closely interlinked with hyperactivity of the hypothalamic-pituitary-adrenocortical (HPA) system, and are likely to be involved in the pathophysiology of anxiety disorders and major depression. We therefore investigated markers of serotonergic transmission and their modulation by chronic paroxetine in rats selectively bred for high (HAB) or low (LAB) anxiety-related behaviour, both under basal conditions and in response to emotional stress. Hippocampal serotonin 1 A (5-HT1A) receptor mRNA expression was reduced in HAB rats, whereas 5-HT concentrations in hippocampal microdialysates did not differ between HAB and LAB rats under basal conditions. In the hippocampus, overall expression of serotonin transporter binding sites was increased in HAB compared with LAB rats. Exposure to emotional stress failed to increase intrahippocampal 5-HT release in HAB rats whereas LAB rats displayed a physiological, albeit small rise. Chronic ...

Although microdialysis (MD) and solid-phase microextraction (SPME) are widely used sampling techniques, a comparison study has not been performed to date. The goal of the research presented was not only to address this issue but also to develop new analytical methods that were more suitable for in vivo study using MD and SPME. A new calibration method called kinetic microdialysis was developed for in vivo sampling. Two MD probes with different flow rates were simultaneously inserted into the symmetric parts of sampling system. A simple empirical equation was proposed to calculate the analyte concentrations in the sample matrix using two different dialysate concentrations. Several factors that influenced the correction factor in this equation were discussed. An excellent correlation was observed between the calculated and theoretical value. This method was subsequently applied for in vivo sampling, for the measurement of pesticide allocation in the different leaves of a jade plant (Crassula ...

Abstract:. Glycemic control of intensive care patients can be beneficial for this patient group but the continuous determination of their glucose concentration is challenging. Current continuous glucose monitoring systems based on the measurement of interstitial fluid glucose concentration struggle with sensitivity losses, resulting from biofouling or inflammation reactions. Their use as decision support systems for the therapeutic treatment is moreover hampered by physiological time delays as well as gradients in glucose concentration between plasma and interstitial fluid. To overcome these drawbacks, we developed and clinically evaluated a system based on microdialysis of whole blood. Venous blood is heparinised at the tip of a double lumen catheter and pumped through a membrane based micro-fluidic device where protein-free microdialysate samples are extracted. Glucose recovery as an indicator of long term stability was studied in vitro with heparinised bovine blood and remained highly stable ...

Background: The microdialysis (MD) technique is widely spread and used both experi-mentally and in clinical practice. The MD technique allows continuous collection of small molecules such as glucose, lactate, pyruvate and glycerol. Samples are often analysed using the CMA 600 analyser, an enzymatic and colorimetric analyser. Data evaluating the performance of the CMA 600 analysis system and associated sample han-dling are sparse. The aim of this work was to identify sources of variability related to han-dling of microdialysis samples and sources of error associated with use of the CMA 600 analyser. Further, to develop and compare different application techniques of the micro-dialysis probes both within an organ and on the surface of an organ.. Material and Methods: Papers I and II are mainly in vitro studies with the exception of the No Net Flux calibration method in paper I where a pig model (n=7) was used to exam-ine the true concen-tration of glucose and urea in subcutaneous tissue. Flow ...

TY - JOUR. T1 - Sodium ion transport participates in non-neuronal acetylcholine release in the renal cortex of anesthetized rabbits. AU - Shimizu, Shuji. AU - Akiyama, Tsuyoshi. AU - Kawada, Toru. AU - Sata, Yusuke. AU - Turner, Michael James. AU - Fukumitsu, Masafumi. AU - Yamamoto, Hiromi. AU - Kamiya, Atsunori. AU - Shishido, Toshiaki. AU - Sugimachi, Masaru. PY - 2017/9. Y1 - 2017/9. N2 - This study examined the mechanism of release of endogenous acetylcholine (ACh) in rabbit renal cortex by applying a microdialysis technique. In anesthetized rabbits, a microdialysis probe was implanted into the renal cortex and perfused with Ringers solution containing high potassium concentration, high sodium concentration, a Na+/K+-ATPase inhibitor (ouabain), or an epithelial Na+ channel blocker (benzamil). Dialysate samples were collected at baseline and during exposure to each agent, and ACh concentrations in the samples were measured by high-performance liquid chromatography. High potassium had no ...

Little attention has been paid to how the presence of roots influences water content measurements obtained with water content sensors. This issue is especially important if sensors are deployed in densely rooted soil or growth media. This work addresses the impact of roots on water content measurements obtained with dual-probe heat-pulse (DPHP) sensors. In the DPHP method, the maximum temperature rise in response to heating (Tmax) is used to calculate volumetric heat capacity, which in turn is used to calculate volumetric water content. The accuracy of DPHP sensors was evaluated in unrooted and rooted 0.25-1 mm baked ceramic aggregate. For both restricted and unrestricted volumes of aggregate the presence of roots caused DPHP sensors to consistently overestimate water content by 0.05-0.09 cm3·cm-3. Measured values of Tmax were lower in the presence of roots, which resulted in overestimation of volumetric heat capacity that was attributed to the high specific heat of water contained in roots in ...

Heres why we recommend HPLC-ECD for neurotransmitter detection.. While there are a few ways to analyze neurotransmitters, like liquid chromatography-mass spectrometry, or LC-MS, ELISA or Radioimmunoassays. However, for qualitative and quantitative analysis of neurotransmitters, we recommend high-performance liquid chromatography detected with an electrochemical detector, known as HPLC-ECD.. The first reason is sensitivity. HPLC-ECD is highly sensitive, down to the femtomolar range. This is suitable for most neuroscience applications, including quantitative analysis of in-vivo microdialysis samples. The second reason is time. Applications using HPLC-ECD can run anywhere from 5 to 30 minutes, where you can detect multiple analytes from a single injection. For example, we have an application for the simultaneous detection of dopamine and serotonin in just 5 minutes. That means you can run over a hundred samples overnight for high throughput using laboratory automation like an autosampler. Weve ...

Other projects are investigating the role of serotonin in the expression and regulation of female sexual behavior. A combination of behavioral and neurochemical techniques are applied. Specific nuclei within the preoptic-hypothalamus continuum are sampled and analyzed for content of monoamines, serotonin and their metabolites. Changes in levels and/or activity of the monoamines are correlated with changes in behavioral receptivity induced by pharmacological (drugs or hormones) or physiological (estrus cycle, neonatal manipulation) means. Dialysis probes are also inserted into the hypothalamus using stereotaxic surgery techniques, and serotonin release is measured in vivo in a conscious rat in relation to lordosis responsivity.. Selected Publications:. Luine, V.N., Mohan, G., Tu, Z. and Efange, S.M.N., Chromaproline and Chromaperidine, nicotine agonists, and Donepezil, cholinesterase inhibitor, enhance memory tasks in ovariectomized rats. Pharmac. Biochem. & Behav. 74: 213-21 (2002 ...

Other projects are investigating the role of serotonin in the expression and regulation of female sexual behavior. A combination of behavioral and neurochemical techniques are applied. Specific nuclei within the preoptic-hypothalamus continuum are sampled and analyzed for content of monoamines, serotonin and their metabolites. Changes in levels and/or activity of the monoamines are correlated with changes in behavioral receptivity induced by pharmacological (drugs or hormones) or physiological (estrus cycle, neonatal manipulation) means. Dialysis probes are also inserted into the hypothalamus using stereotaxic surgery techniques, and serotonin release is measured in vivo in a conscious rat in relation to lordosis responsivity.. Selected Publications:. Luine, V.N., Mohan, G., Tu, Z. and Efange, S.M.N., Chromaproline and Chromaperidine, nicotine agonists, and Donepezil, cholinesterase inhibitor, enhance memory tasks in ovariectomized rats. Pharmac. Biochem. & Behav. 74: 213-21 (2002 ...

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BioAssay record AID 426688 submitted by ChEMBL: Increase in extracellular serotonin level in frontal cortex of awake and free moving rat at 1 mg/kg, po by microdialysis relative to basal level.

The Thermo Scientific Pierce 96-well Deep-well Plate, 2.2 mL, is a polypropylene deep-well assay plate suficient for 96 microdialysis devices.|br||br||b|Related Products|/b||br||a

BACKGROUND AND PURPOSEF15599, a novel 5-hydroxytryptamine (5-HT)(1A) receptor agonist with 1000-fold selectivity for 5-HT compared with other monoamine receptors, shows antidepressant and procognitive activity at very low doses in animal models. We examined the in vivo activity of F15599 at somatodendritic autoreceptors and postsynaptic 5-HT(1A) heteroreceptors.EXPERIMENTAL APPROACHIn vivo single unit and local field potential recordings and microdialysis in the rat.KEY RESULTSF15599 increased the discharge rate of pyramidal neurones in medial prefrontal cortex (mPFC) from 0.2 microg x kg(-1) i.v and reduced that of dorsal raphe 5-hydroxytryptaminergic neurones at doses ,10-fold higher (minimal effective dose 8.2 microg x kg(-1) i.v.). Both effects were reversed by the 5-HT(1A) antagonist (+/-)WAY100635. F15599 did not alter low frequency oscillations (approximately 1 Hz) in mPFC. In microdialysis studies, F15599 increased dopamine output in mPFC (an effect dependent on the activation of ...

Video articles in JoVE about acrylic resins include Acrylic Resin Molding Based Head Fixation Technique in Rodents, Nano-fEM: Protein Localization Using Photo-activated Localization Microscopy and Electron Microscopy, Application of Light-cured Dental Adhesive Resin for Mounting Electrodes or Microdialysis Probes in Chronic Experiments.

The HSE-HA MiniVent Mouse Ventilator is an ideal ventilator suited for mice. It is remarkable small in size and can be placed close to the animal. It provides a stroke volume from 30 to 350 µl and can ventilate from 60 to 400 breaths/minute. The stroke volume may be adjusted while the ventilator is running ...

Just for Mouse™ Stereotaxic Instruments THE JUST FOR MOUSE™ STEREOTAXIC INSTRUMENTS is ideal for researchers working with mice and other small rodents. Precision alignment when

Postoperative anastomotic leakage is a serious complication in patients with oesophageal or cardia cancer. Early diagnosis and treatment are mandatory.

Our head block tether assemblies were designed for microdialysis, but also work well for standard infusion applications. In fact, we have found that the head block tether is the best option for all applications when working with mice. It provides a solid attachment to the animal with little risk of infection.

Beyond microdialysis, behavioral, EEG, electrophysiology and bioanalytical services, we also offer a variety of other supplemental and complementary services and study types.