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Analytical and Bioanalytical Chemistry Apr 2022This article will debate the usefulness of POCT measurements and the contribution microdialysis can make to generating valuable information. A particular theme will be... (Review)
Review
This article will debate the usefulness of POCT measurements and the contribution microdialysis can make to generating valuable information. A particular theme will be the rarely considered difference between ex vivo sampling, which typically generates only a static measure of concentration, and in vivo measurements that are subject to dynamic changes due to mass transfer. Those dynamic changes provide information about the patients' physiological state.
Topics: Humans; Microdialysis
PubMed: 35028692
DOI: 10.1007/s00216-021-03830-6 -
Methods in Molecular Biology (Clifton,... 2022Pineal microdialysis is characterized by the real-time monitoring of melatonin, neurotransmitters, metabolites, and other compounds released by the pineal gland...
Pineal microdialysis is characterized by the real-time monitoring of melatonin, neurotransmitters, metabolites, and other compounds released by the pineal gland throughout 24 h. It is a technique with great advantages that allows in vivo study of the ongoing pineal gland metabolism. In this chapter, we describe the entire process of pineal microdialysis that includes probe manufacturing, surgical procedure for its implantation, and the sample collection process.
Topics: Circadian Rhythm; Melatonin; Microdialysis; Pineal Gland
PubMed: 36180678
DOI: 10.1007/978-1-0716-2593-4_9 -
Critical Care Nursing Clinics of North... Mar 2016A variety of neuromonitoring techniques are available to aid in the care of neurocritically ill patients. However, traditional monitors lack the ability to measure brain... (Review)
Review
A variety of neuromonitoring techniques are available to aid in the care of neurocritically ill patients. However, traditional monitors lack the ability to measure brain biochemistry and may provide inadequate warning of potentially reversible deleterious conditions. Cerebral microdialysis (CMD) is a safe, novel method of monitoring regional brain biochemistry. Analysis of CMD analytes as part of a multimodal approach may help inform clinical decision making, guide medical treatments, and aid in prognostication of patient outcome. Its use is most frequently documented in traumatic brain injury and subarachnoid hemorrhage. Incorporating CMD into clinical practice is a multidisciplinary effort.
Topics: Brain; Brain Injuries; Humans; Microdialysis; Subarachnoid Hemorrhage
PubMed: 26873764
DOI: 10.1016/j.cnc.2015.09.005 -
Fluids and Barriers of the CNS Dec 2021Contemporary biomarker collection techniques in blood and cerebrospinal fluid have to date offered only modest clinical insights into neurologic diseases such as... (Review)
Review
Contemporary biomarker collection techniques in blood and cerebrospinal fluid have to date offered only modest clinical insights into neurologic diseases such as epilepsy and glioma. Conversely, the collection of human electroencephalography (EEG) data has long been the standard of care in these patients, enabling individualized insights for therapy and revealing fundamental principles of human neurophysiology. Increasing interest exists in simultaneously measuring neurochemical biomarkers and electrophysiological data to enhance our understanding of human disease mechanisms. This review compares microdialysis, microperfusion, and implanted EEG probe architectures and performance parameters. Invasive consequences of probe implantation are also investigated along with the functional impact of biofouling. Finally, previously developed microdialysis electrodes and microperfusion electrodes are reviewed in preclinical and clinical settings. Critically, current and precedent microdialysis and microperfusion probes lack the ability to collect neurochemical data that is spatially and temporally coincident with EEG data derived from depth electrodes. This ultimately limits diagnostic and therapeutic progress in epilepsy and glioma research. However, this gap also provides a unique opportunity to create a dual-sensing technology that will provide unprecedented insights into the pathogenic mechanisms of human neurologic disease.
Topics: Biomarkers; Electrocorticography; Humans; Microdialysis; Nervous System Diseases; Neurophysiological Monitoring
PubMed: 34852829
DOI: 10.1186/s12987-021-00292-x -
Current Pharmaceutical Biotechnology Jun 2002Microdialysis has been used extensively in animal studies for decades and in human pharmacokinetic studies for about 10 years. Microdialysis is based on the passive... (Review)
Review
Microdialysis has been used extensively in animal studies for decades and in human pharmacokinetic studies for about 10 years. Microdialysis is based on the passive diffusion of a compound along its concentration gradient from the tissue through the membrane into the dialysate. Microdialysis samples from the interstitial space which is a defined, anatomical compartment; there is no net loss of body fluid; the sample is "purified" and no enzymatic degradation takes place because proteins do not pass through the probe membrane into the dialysate; microdialysis data relate to the intact molecule; time resolution is high compared to biopsy and skin blister techniques; radioabelling or induction of a magnetic response is not needed; microdialysis is also an alternative method to determine protein binding of a compound in vivo; microdialysis can readily be set up in clinical research units without expensive infrastructure. Microdialysis has been used to measure tissue concentrations of endogenous compounds and to investigate the tissue penetration of drugs in a variety of tissues in humans in vivo in both healthy volunteers and patients. Microdialysis data have also been used in PK-PD modelling and to obtain concentration-response relationships locally in tissues in vivo. There are also studies combining microdialysis with imaging techniques, e.g. PET. Microdialysis data may be used in early studies to select the appropriate compound, to optimise dosing regimens and to investigate the kinetic and dynamic consequences in the tissues of drug-drug and drug-disease interactions. Microdialysis can also be used in late phase studies to provide tissue concentration data in support of therapeutic efficacy trials or to create a niche for an already marketed drug. FDA and CPMP documents emphasise the value and importance of human tissue drug concentration data and support the use of microdialysis in humans to obtain such information. Microdialysis can satisfy regulatory requirements by providing data on drug concentrations in a well-defined anatomical tissue compartment at or close to the effect target site. Microdialysis is a versatile technique because of its multifaceted utility, low cost, ease of use, adaptability to different types of compounds and its feasibility for a number of organs and tissues. Equipment and probes for use in various organs have been commercially available for years.
Topics: Animals; Brain; Drug Delivery Systems; Humans; Microdialysis; Tomography, Emission-Computed
PubMed: 12022259
DOI: 10.2174/1389201023378373 -
The AAPS Journal Sep 2017Microdialysis has contributed with very important knowledge to the understanding of target-specific concentrations and their relationship to pharmacodynamic effects from... (Review)
Review
Microdialysis has contributed with very important knowledge to the understanding of target-specific concentrations and their relationship to pharmacodynamic effects from a systems pharmacology perspective, aiding in the global understanding of drug effects. This review focuses on the historical development of microdialysis as a method to quantify the pharmacologically very important unbound tissue concentrations and of recent findings relating to modeling microdialysis data to extrapolate from rodents to humans, understanding distribution of drugs in different tissues and disease conditions. Quantitative microdialysis developed very rapidly during the early 1990s. Method development was in focus in the early years including development of quantitative microdialysis, to be able to estimate true extracellular concentrations. Microdialysis has significantly contributed to the understanding of active transport at the blood-brain barrier and in other organs. Examples are presented where microdialysis together with modeling has increased the knowledge on tissue distribution between species, in overweight patients and in tumors, and in metabolite contribution to drug effects. More integrated metabolomic studies are still sparse within the microdialysis field, although a great potential for tissue and disease-specific measurements is evident.
Topics: Humans; Microdialysis; Pharmacology; Research Design
PubMed: 28762127
DOI: 10.1208/s12248-017-0108-2 -
Scandinavian Journal of Clinical and... Dec 2016Microdialysis is used for in vivo sampling of extracellular molecules. The technique provides a continuous and dynamic view of concentrations of both endogenous released... (Review)
Review
Microdialysis is used for in vivo sampling of extracellular molecules. The technique provides a continuous and dynamic view of concentrations of both endogenous released and exogenous administered substances. Microdialysis carries a low risk of complications and has proven to be a safe procedure in humans. The technique has been applied in several clinical areas, including gastrointestinal surgery. Microdialysis may be used for studies of tissue metabolism, and the technique is also a promising tool for pharmacological studies of drug penetration into abdominal organ tissue and the peritoneal cavity. The clinical significance of intraabdominal microdialysis in postoperative monitoring of surgical patients has yet to be proven. In this review, we introduce the microdialysis technique, and we present an overview of theoretical and practical considerations that should be taken into account when using microdialysis in intraabdominal clinical research.
Topics: Abdominal Cavity; Diffusion; Digestive System Surgical Procedures; Extracellular Fluid; Glucose; Glycerol; Humans; Infusion Pumps; Lactic Acid; Membranes, Artificial; Microdialysis; Monitoring, Physiologic; Postoperative Care; Pyruvic Acid; Rheology
PubMed: 27701896
DOI: 10.1080/00365513.2016.1233574 -
Pharmacology, Biochemistry, and Behavior Aug 2008
Topics: Animals; Microdialysis
PubMed: 18499240
DOI: 10.1016/j.pbb.2008.04.015 -
Cerebral Microdialysis as a Tool for Assessing the Delivery of Chemotherapy in Brain Tumor Patients.World Neurosurgery Jan 2021The development of curative treatment for glioblastoma has been extremely challenging. Chemotherapeutic agents that have seemed promising have failed in clinical trials.... (Review)
Review
The development of curative treatment for glioblastoma has been extremely challenging. Chemotherapeutic agents that have seemed promising have failed in clinical trials. Drugs that can successfully target cancer cells within the brain must first traverse the brain interstitial fluid. Cerebral microdialysis (CMD) is an invasive technique in which interstitial fluid can be directly sampled. CMD has primarily been used clinically in the setting of head trauma and subarachnoid hemorrhage. Our goal was to review the techniques, principles, and new data pertaining to CMD to highlight its use in neuro-oncology. We conducted a literature search using the PubMed database and selected studies in which the investigators had used CMD in either animal brain tumor models or clinical trials. The references were reviewed for additional information. Studies of CMD have shown its importance as a neurosurgical technique. CMD allows for the collection of pharmacokinetic data on drug penetrance across the blood-brain barrier and metabolic data to characterize the response to chemotherapy. Although no complications have been reported, the current CMD technique (as with any procedure) has risks and limitations, which we have described in the present report. Animal CMD experiments have been used to exclude central nervous system drug candidates from progressing to clinical trials. At present, patients undergoing CMD have been monitored in the intensive care unit, owing to the requisite tethering to the apparatus. This can be expected to change soon because of advances in microminiaturization. CMD is an extremely valuable, yet underused, technique. Future CMD applications will have central importance in assessing drug delivery to tumor cells in vivo, allowing a pathway to successful therapy for malignant brain tumors.
Topics: Animals; Antineoplastic Agents; Blood-Brain Barrier; Brain Neoplasms; Humans; Microdialysis
PubMed: 32890850
DOI: 10.1016/j.wneu.2020.08.161 -
Neurosurgery Clinics of North America Jul 2013Effective monitoring is critical for neurologically compromised patients, and several techniques are available. One of these tools, cerebral microdialysis (MD), was... (Review)
Review
Effective monitoring is critical for neurologically compromised patients, and several techniques are available. One of these tools, cerebral microdialysis (MD), was designed to detect derangements in cerebral metabolism. Although this monitoring device began as a research instrument, favorable results and utility have broadened its clinical applications. Combined with other brain monitoring techniques, MD can be used to estimate cerebral vulnerability, to assess tissue outcome, and possibly to prevent secondary ischemic injury by guiding therapy. This article reviews the literature regarding the past, present, and future uses of MD along with its advantages and disadvantages in the intensive care unit setting.
Topics: Brain Injuries; Cerebrovascular Circulation; Critical Care; Humans; Microdialysis; Treatment Outcome
PubMed: 23809035
DOI: 10.1016/j.nec.2013.02.002