A tubular microdialysis probe is made from polysulfone hollow fibre for human haemodialysis, which has an inner diameter of 200 μm and a thickness of 20 μm. Milk is deposited to the outer surface of the hollow fibre and allowed to dry to form a dry sample. The tubular probe is then connected to the syringe pump and microdialysis of the dry sample into 0.5 mol/L HCl as acceptor is performed. 2.5 μL of microdialysate is obtained and analyzed for inorganic cations by capillary electrophoresis with contactless conductivity detection. Baseline separation of NH4+, K+, Ca2+, Na+, Mg2+, Li+ is achieved in 5.5 mol/L acetic acid as background electrolyte using a fused silica capillary with inner diameter of 25 μm and length of 31.5 cm. The reproducibility of dry sample microdialysis including CE analysis for peak area ranges from 2.4 to 3.9 % after normalization to Li+ as internal standard.
- MeSH
- elektroforéza kapilární * přístrojové vybavení metody MeSH
- kationty * analýza MeSH
- mikrodialýza * přístrojové vybavení metody MeSH
- mléko * chemie MeSH
- skot MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
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.
OBJECTIVE: Cerebral microdialysis (CMD) is a method used to measure the concentration of metabolites and glycerol in the interstitium of the brain. The aim of this study was to investigate the effect of parenterally applied medication and nutrition containing external free glycerol (EFG) on cerebral values of glycerol in patients monitored and treated for non-traumatic subarachnoid hemorrhage (SAH). METHODS: In 13 patients, the values of CG concentrations were measured using CMD. The amounts of parenterally applied EFG (in hourly intervals) were calculated from patient records. All data were gathered retrospectively. To analyze the association between the parameters of interest and their relationship, Spearman ́s correlation and p-values were calculated. RESULTS: There was no evident relationship between the CG and EFG concentrations when the dataset was analyzed as a whole (r = –0.146). However, when the analysis was applied to single patients, a varying degree of correlations was discovered in 7 patients (r = 0.431–0.867). CONCLUSION: The possible effect of externally administered glycerol contained in pharmaceuticals and nutrition on its brain concentrations must be considered when interpreting data of CMD (Tab. 2, Fig. 4, Ref. 16)
BACKGROUND: Inadequate blood supply is one of the major risk factors for anastomotic leak after low anterior rectal resection. Early detection of ischemia might predict complicated healing and enable anastomotic salvage, which is associated with better outcomes. A microdialysis offers a real-time evaluation of adequate bowel perfusion through monitoring of tissue metabolism. In this experimental study, we assessed the role of microdialysis in detecting early ischemia after colorectal anastomosis. MATERIALS AND METHODS: Colorectal anastomosis was performed in six miniature pigs. A microdialysis catheter was placed on the bowel serosa 5 mm proximal to the anastomosis. Metabolic changes were monitored hourly before and after initiating ischemia, which was induced by ligation of the inferior mesenteric artery and skeletonization of the mesocolon. RESULTS: Significant increase in tissue levels of lactate was detected after 60 min of ischemia (13.6 [10.4-16.1] versus 6.75 [1.8-9.6] mmol/L at baseline; P < 0.005). The lactate/pyruvate ratio increased accordingly. The concentration of glycerol increased significantly after 2 hours-from a baseline value of 29.5 (3-84) to 125 (79-201) mmol/L (P < 0.005). The decrease in glucose levels was also significant after 60 minutes-0 (0-0.2) versus 4.7 (3.3-6.8) mmol/L at baseline. However, its values started to decline before ischemia. CONCLUSIONS: Surface microdialysis can detect ischemic changes early and may be a promising method in postoperative monitoring of colorectal anastomosis.
- MeSH
- anastomóza chirurgická * škodlivé účinky MeSH
- glycerol metabolismus MeSH
- ischemie * MeSH
- krevní glukóza analýza MeSH
- kyselina mléčná metabolismus MeSH
- mikrodialýza * metody MeSH
- miniaturní prasata MeSH
- pooperační komplikace * MeSH
- prasata MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
Two methods of capillary electrophoresis with contactless conductivity detection have been developed for monitoring the levels of glucose and lactate in clinical samples. The separations are performed in uncoated fused silica capillaries with inner diameter 10 or 20 μm, total length 31.5 cm, length to detector 18 cm, using an Agilent electrophoretic instrument with an integrated contactless conductivity detector. Glucose is determined in optimized background electrolyte, 50 mM NaOH with pH 12.6 and 2-deoxyglucose is used as an internal standard; the determination of lactate is performed in 40 mM CHES/NaOH with pH 9.4 and lithium cations as an internal standard. Both substances are determined in minimal volumes of (1) nutrient media after cell incubation, and (2) microdialysates of human adipose tissue; after dilution and filtration as the only treatment of the sample. The migration time of glucose is 2.5 min and that of lactate is 1.5 min with detection limits at the micromolar concentration level. The developed techniques are suitable for sequential monitoring of glucose and lactate over time during metabolic experiments.
- MeSH
- elektrická vodivost * MeSH
- elektroforéza kapilární metody MeSH
- glukosa analýza MeSH
- kalibrace MeSH
- kultivační média chemie MeSH
- kultivované buňky MeSH
- kyselina mléčná analýza MeSH
- lidé MeSH
- mikrodialýza metody MeSH
- tuková tkáň MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Metabolism of human adipose tissue during acute exercise is monitored by microdialysis. The metabolites are analysed in the microdialysate using capillary electrophoresis (CE) on a short separation path in combination with a contactless conductivity detector (C4D). Four completely new CE/C4D methods were developed for determination of nutrients and metabolites in 10 µL of microdialysate. All methods are characterised by a short separation time and simple sample preparation based primarily on 4-fold dilution of microdialysate. The intra-day repeatability for the migration time varied in the range 0.4 - 0.9% and that for the peak area equalled 0.7 - 2.4%; the inter-day repeatability of the migration time was in the range 1.2 - 2.3% and the range for the peak area was 2.5 - 5.0%; all the values were measured as RSD. The developed determination was employed for sequenced monitoring of the levels of lactate, glycerol and branched chain amino acids in microdialysates taken from the abdominal adipose tissue during acute physical exercise. The stress test lasted 3 h and the metabolites were monitored at 15 min intervals.
- MeSH
- cvičení fyziologie MeSH
- dospělí MeSH
- elektrická vodivost MeSH
- elektroforéza kapilární metody MeSH
- glycerol analýza MeSH
- kyselina mléčná analýza MeSH
- lidé MeSH
- metabolomika metody MeSH
- mikrodialýza metody MeSH
- tuková tkáň metabolismus MeSH
- větvené aminokyseliny analýza MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Úvod: Nedostatečné krevní zásobení představuje jeden z hlavních rizikových faktorů dehiscence anastomózy. Včasná detekce lokálních ischemických změn by mohla predikovat komplikace, předejít rozvoji peritonitidy, snížit mortalitu a zvýšit šanci na záchranu funkční anastomózy. Mikrodialýza nabízí možnost kontinuální monitorace prostřednictvím hodnocení aktivity tkáňového metabolismu. Hlavním cílem této práce bylo ověřit, zda mikrodialýza umožňuje monitoraci ischemických změn kolo-rektální anastomózy. Metoda: Do studie jsme zařadili 5 prasat s ručně šitou kolorektální anastomózou. Mikrodialyzační katétr byl zaveden intramurálně 5mm od okraje anastomózy. Tkáňové hladiny metabolitů byly sledovány každých 60 minut po dobu 6 hodin. Po třech měřeních byla provedena ischemizace anastomózy, po které následovaly další 3 hodiny monitorace. Ke srovnání hodnot před a po ischemii byl použit Mann-Whitney test. Výsledky: Po ischemizaci anastomózy došlo k signifikantnímu poklesu tkáňové hladiny glukózy a pyruvátu. Naopak hladiny laktátu a glycerolu signifikantně vzrostly. Všechny detekované změny byly signifikantní již během prvních 60 minut po vyvolání ischemie. Závěr: Monitorace kolorektální anastomózy pomocí mikrodialýzy je technicky proveditelná a umožňuje včasné zachycení poruch perfuze.
Introduction: Inadequate blood supply is one of the major risk factors for colorectal anastomotic leak. Early postoperative detection of local ischemic changes can predict complicated healing and lead to better outcome. Microdialysis (MD) offers real-time evaluation of adequate bowel perfusion through monitoring of tissue metabolism. The aim of this study was to assess the feasibility of MD for early detection of ischemic changes in colorectal anastomosis. Method: Five pigs with end-to-end colorectal anastomosis were included. MD catheter was placed intramurally 5mm from anastomotic edge. Occlusive ischemia was induced after 3 measurements and followed by another 3 hours of monitoring. Tissue levels of different metabolites were measured every 60 minutes before and after ischemia induction. Mann-Whitney test was used to compare pre and post ischemic changes. Results: The monitoring of colorectal anastomosis using MD was technically feasible and associated with no complications. Significant changes caused by local ischemia were observed in decreased levels of glucose or pyruvate and increased levels of lactate and glycerol. All metabolic changes were detectable already in first samples 60 minutes after ischemia induction. Conclusion: Postoperative ischemic changes in colorectal anastomosis can be detected by means of microdialysis.
- Klíčová slova
- kolorektální anastomóza,
- MeSH
- anastomóza chirurgická * MeSH
- dehiscence operační rány * prevence a kontrola MeSH
- kolorektální chirurgie metody MeSH
- mikrodialýza metody MeSH
- modely nemocí na zvířatech MeSH
- pooperační komplikace prevence a kontrola MeSH
- pooperační období MeSH
- pooperační péče metody MeSH
- prasata MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
An increasing number of studies over the past few years have demonstrated ghrelin's role in alcohol, cocaine and nicotine abuse. However, the role of ghrelin in opioid effects has rarely been examined. Recently we substantiated in rats that ghrelin growth hormone secretagogue receptors (GHS-R1A) appear to be involved in acute opioid-induced changes in the mesolimbic dopaminergic system associated with the reward processing. The aim of the present study was to ascertain whether a ghrelin antagonist (JMV2959) was able to inhibit morphine-induced biased conditioned place preference and challenge-morphine-induced accumbens dopaminergic sensitization and behavioral sensitization in adult male rats. In the place preference model, the rats were conditioned for 8 days with morphine (10 mg/kg s.c.). On the experimental day, JMV2959 (3 and 6 mg/kg i.p.) or saline were administered before testing. We used in vivo microdialysis to determine changes of dopamine and its metabolites in the nucleus accumbens in rats following challenge-morphine dose (5 mg/kg s.c.) with or without JMV2959 (3 and 6 mg/kg i.p.) pretreatment, administered on the 12th day of spontaneous abstinence from morphine repeated treatment (5 days, 10-40 mg/kg). Induced behavioral changes were simultaneously monitored. Pretreatment with JMV2959 significantly and dose dependently reduced the morphine-induced conditioned place preference and significantly and dose dependently reduced the challenge-morphine-induced dopaminergic sensitization and affected concentration of by-products associated with dopamine metabolism in the nucleus accumbens. JMV2959 pretreatment also significantly reduced challenge-morphine-induced behavioral sensitization. Our present data suggest that GHS-R1A antagonists deserve to be further investigated as a novel treatment strategy for opioid addiction.
- MeSH
- dopamin * metabolismus MeSH
- glycin analogy a deriváty farmakologie MeSH
- krysa rodu rattus MeSH
- mikrodialýza metody MeSH
- morfin aplikace a dávkování antagonisté a inhibitory MeSH
- nucleus accumbens účinky léků metabolismus MeSH
- operantní podmiňování účinky léků fyziologie MeSH
- opioidní analgetika aplikace a dávkování antagonisté a inhibitory MeSH
- potkani Wistar MeSH
- receptory ghrelinu antagonisté a inhibitory metabolismus MeSH
- triazoly farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Nitric oxide (NO) chemistry inside the body is the most interesting part of its behavior. NO is involved in controlling blood pressure, and in transmitting nerve signals and a variety of other signaling processes. To explain the behavior of NO, it is necessary to determine its immediate concentration or observe time-dependent changes in its concentration. In Paramecium caudatum, NO is formed by calcium-dependent nNOS (NOS1)-like protein, which is distributed in the cytoplasm. NO synthesis affects the ciliary beat and consequent motility of cells and blocked NO synthesis reduces the ability of cells to move. The possibility of online coupling of microdialysis (of P. caudatum solution) with NO detection is demonstrated. Direct measurement of NO is carried out using dilute Bluestar® Forensic reagent (luminol-H2 O2 system; one of the NO detections is based upon the chemiluminescent reaction between NO and the luminol-H2 O2 system, which is specifically reactive to NO). The effect of a nitric oxide synthase inhibitor, NG-nitro-l-arginine methyl ester was observed. NO production was inhibited and the movement of P. caudatum was restricted. These effects were time dependent and after a specific time were reversed.
- MeSH
- inhibitory enzymů farmakologie MeSH
- luminiscenční měření MeSH
- luminol chemie MeSH
- mikrodialýza metody MeSH
- NG-nitroargininmethylester farmakologie MeSH
- oxid dusnatý analýza chemie metabolismus MeSH
- Paramecium caudatum chemie metabolismus MeSH
- peroxid vodíku chemie MeSH
- synthasa oxidu dusnatého antagonisté a inhibitory MeSH
- Publikační typ
- časopisecké články MeSH
