Determination of the temperature-dependent electric conductivity of liver tissue ex vivo and in vivo: Importance for therapy planning for the radiofrequency ablation of liver tumours

AbstractMephedrone is a widely used drug of abuse, exerting its effects by interacting with monoamine transporters. Although this mechanism has been widely studied heretofore, little is known about the involvement of glutamatergic transmission in mephedrone effects. In this study, we comprehensively evaluated glutamatergic involvement in rewarding effects of mephedrone using an interdisciplinary approach including (1) behavioural study on effects of memantine (non-selective NMDA antagonist) on expression of mephedrone-induced conditioned place preference (CPP) in rats; (2) evaluation of glutamate concentrations in the hippocampus of rats following 6 days of mephedrone administration, using in vivo magnetic resonance spectroscopy (MRS); and (3) determination of glutamate levels in the hippocampus of rats treated with mephedrone and subjected to MRS, using ion-exchange chromatography. In the presented research, we confirmed priorly reported mephedrone-induced rewarding effects in the CPP paradigm and showed that memantine (5 mg/kg) was able to reverse the expression of this effect. MRS study showed that subchronic mephedrone administration increased glutamate level in the hippocampus when measured in vivo 24 h (5 mg/kg, 10 mg/kg and 20 mg/kg) and 2 weeks (5 mg/kg and 20 mg/kg) after last injection. Ex vivo chromatographic analysis did not show significant changes in hippocampal glutamate concentrations; however, it showed similar results as obtained in the MRS study proving its validity. Taken together, the presented study provides new insight into glutamatergic involvement in rewarding properties of mephedrone.

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Comparison of the Resistance to Bending Forces of the 4.5 LCP Plate-rod Construct and of 4.5 LCP Alone Applied to Segmental Femoral Defects in Miniature Pigs

Acta Veterinaria Brno ◽

10.2754/avb201079040613 ◽

2010 ◽

Vol 79 (4) ◽

pp. 613-620 ◽

Cited By ~ 2

Author(s):

Lucie Urbanová ◽

Robert Srnec ◽

Pavel Proks ◽

Ladislav Stehlík ◽

Zdeněk Florian ◽

...

Keyword(s):

Ex Vivo ◽

Femoral Diaphysis ◽

Miniature Pig ◽

Femoral Bone ◽

Bone Implant ◽

Miniature Pigs ◽

Bone Defect Healing ◽

Considerable Strain

The study deals with the determination of mechanical properties, namely resistance to bending forces, of flexible buttress osteosynthesis using two different bone-implant constructs stabilizing experimental segmental femoral bone defects (segmental ostectomy) in a miniature pig ex vivo model using 4.5 mm titanium LCP and a 3 mm intramedullary pin (“plate and rod” construct) (PR-LCP), versus the 4.5 mm titanium LCP alone (A-LCP). The “plate and rod” fixation (PR-LCP) of the segmental femoral defect is significantly more resistant (p < 0.05) to bending forces (200 N, 300 N, and 500 N) than LCP alone (A-LCP). Stabilisation of experimental segmental lesions of the femoral diaphysis in miniature pigs by flexible bridging osteosynthesis 4.5 mm LCP in combination with the “plate and rod” construct appears to be a suitable fixation of non-reducible fractures where considerable strain of the implants by bending forces can be assumed. These findings will be used in upcoming in vivo experiments in the miniature pig to investigate bone defect healing after transplantation of mesenchymal stem cells in combination with biocompatible scaffolds.

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Electronic determination of root canal working length in primary molar teeth: an in vivo and ex vivo study

International Endodontic Journal ◽

10.1111/j.1365-2591.2010.01839.x ◽

2011 ◽

Vol 44 (5) ◽

pp. 402-406 ◽

Cited By ~ 17

Author(s):

A. P. C. A. Beltrame ◽

T. C. Triches ◽

N. Sartori ◽

M. Bolan

Keyword(s):

Root Canal ◽

Ex Vivo ◽

Primary Molar ◽

Working Length ◽

Molar Teeth ◽

Ex Vivo Study

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IDENTIFICATION AND DETERMINATION OF NEUTRAL STEROID SULPHATES IN HUMAN FOETAL ADRENAL AND LIVER TISSUE

Acta Endocrinologica ◽

10.1530/acta.0.0640273 ◽

1970 ◽

Vol 64 (2) ◽

pp. 273-286 ◽

Cited By ~ 16

Author(s):

I. Huhtaniemi ◽

T. Luukkainen ◽

R. Vihko

Keyword(s):

Mass Spectrometry ◽

Liver Tissue ◽

Keto Group ◽

Gas Chromatography Mass Spectrometry ◽

Gas Liquid Chromatography ◽

Silyl Ethers ◽

Adrenal Tissue ◽

Neutral Steroid

ABSTRACT The endogenous neutral steroids in adrenal and liver tissue obtained from foetuses of 12–17 weeks gestation were investigated. After extractions, the steroids were fractionated into a monosulphate and a disulphate fraction on Sephadex LH-20. The conjugates were cleaved by solvolysis, and purified on silicic acid and their trimethyl silyl ethers were analysed by gas-liquid chromatography and gas chromatography-mass spectrometry. Only neutral steroid monosulphates were found. The following compounds were identified in the monosulphate fraction of adrenal tissue: dehydroepiandrosterone, 16α-hydroxydehydroepiandrosterone, pregnenolone and 17α-hydroxypregnenolone, and of liver tissue; dehydroepiandrosterone, 16α-hydroxydehydroepiandrosterone, androst-5-ene-3β,16α,17β-triol, pregnenolone, 17α-hydroxypregnenolone and 16α-hydroxypregnenolone. The identifications and the results of the quantitative determinations of endogenous neutral steroid sulphates suggest that pregnenolone is synthesised in vivo in the foetal adrenal and converted to 17α-hydroxypregnenolone and dehydroepiandrosterone sulphates. The latter compound is further transformed to 16α-hydroxydehydroepiandrosterone sulphate. No 16α-hydroxylation of pregnenolone was observed in adrenal tissue, whereas liver tissue seems to form 16α-hydroxypregnenolone. Reduction of a 17-keto group to 17β-hydroxyl and a 20-keto group to 20α-hydroxyl seems to take place in liver but not in adrenal tissue.

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Determination of Elastic Modulus in Mouse Bones Using a Nondestructive Micro-Indentation Technique Using Reference Point Indentation

Journal of Biomechanical Engineering ◽

10.1115/1.4039982 ◽

2018 ◽

Vol 140 (7) ◽

Author(s):

Ganesh Thiagarajan ◽

Mark T. Begonia ◽

Mark Dallas ◽

Nuria Lara-Castillo ◽

JoAnna M. Scott ◽

...

Keyword(s):

Elastic Modulus ◽

Reference Point ◽

Ex Vivo ◽

Numerical Procedure ◽

Indentation Modulus ◽

Three Point Bending ◽

Bending Modulus ◽

Reference Point Indentation

The determination of the elastic modulus of bone is important in studying the response of bone to loading and is determined using a destructive three-point bending method. Reference point indentation (RPI), with one cycle of indentation, offers a nondestructive alternative to determine the elastic modulus. While the elastic modulus could be determined using a nondestructive procedure for ex vivo experiments, for in vivo testing, the three-point bending technique may not be practical and hence RPI is viewed as a potential alternative and explored in this study. Using the RPI measurements, total indentation distance (TID), creep indentation distance, indentation force, and the unloading slope, we have developed a numerical analysis procedure using the Oliver–Pharr (O/P) method to estimate the indentation elastic modulus. Two methods were used to determine the area function: (1) Oliver–Pharr (O/P—based on a numerical procedure) and (2) geometric (based on the calculation of the projected area of indentation). The indentation moduli of polymethyl methacrylate (PMMA) calculated by the O/P (3.49–3.68 GPa) and geometric (3.33–3.49 GPa) methods were similar to values in literature (3.5–4 GPa). In a study using femurs from C57Bl/6 mice of different ages and genders, the three-point bending modulus was lower than the indentation modulus. In femurs from 4 to 5 months old TOPGAL mice, we found that the indentation modulus from the geometric (5.61 ± 1.25 GPa) and O/P (5.53 ± 1.27 GPa) methods was higher than the three-point bending modulus (5.28 ± 0.34 GPa). In females, the indentation modulus from the geometric (7.45 ± 0.86 GPa) and O/P (7.46 ± 0.92 GPa) methods was also higher than the three-point bending modulus (7.33 ± 1.13 GPa). We can conclude from this study that the RPI determined values are relatively close to three-point bending values.

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A comparison of microwave ablation and bipolar radiofrequency ablation both with an internally cooled probe: Results in ex vivo and in vivo porcine livers

European Journal of Radiology ◽

10.1016/j.ejrad.2009.12.009 ◽

2011 ◽

Vol 79 (1) ◽

pp. 124-130 ◽

Cited By ~ 88

Author(s):

Jie Yu ◽

Ping Liang ◽

Xiaoling Yu ◽

Fangyi Liu ◽

Lei Chen ◽

...

Keyword(s):

Radiofrequency Ablation ◽

Microwave Ablation ◽

Ex Vivo ◽

Bipolar Radiofrequency ◽

Internally Cooled

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Detection of allergen-induced airway hyperresponsiveness in isolated mouse lungs

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00011.2005 ◽

2006 ◽

Vol 291 (3) ◽

pp. L466-L472 ◽

Cited By ~ 22

Author(s):

Martin Witzenrath ◽

Birgit Ahrens ◽

Stefanie M. Kube ◽

Armin Braun ◽

Heinz G. Hoymann ◽

...

Keyword(s):

Airway Hyperresponsiveness ◽

Ex Vivo ◽

Whole Body ◽

Strongly Correlated ◽

Ex Vivo Model ◽

Isolated Lungs ◽

Spontaneously Breathing

Airway hyperresponsiveness (AHR) is a hallmark of bronchial asthma. Important features of this exaggerated response to bronchoconstrictive stimuli have mostly been investigated in vivo in intact animals or in vitro in isolated tracheal or bronchial tissues. Both approaches have important advantages but also certain limitations. Therefore, the aim of our study was to develop an ex vivo model of isolated lungs from sensitized mice for the investigation of airway responsiveness (AR). BALB/c mice were sensitized by intraperitoneal ovalbumin (Ova) and subsequently challenged by Ova inhalation. In vivo AR was measured in unrestrained animals by whole body plethysmography after stimulation with aerosolized methacholine (MCh) with determination of enhanced pause ( Penh). Twenty-four hours after each Penh measurement, airway resistance was continuously registered in isolated, perfused, and ventilated lungs on stimulation with inhaled or intravascular MCh or nebulized Ova. In a subset of experiments, in vivo AR was additionally measured in orotracheally intubated, spontaneously breathing mice 24 h after Penh measurement, and lungs were isolated further 24 h later. Isolated lungs of allergen-sensitized and -challenged mice showed increased AR after MCh inhalation or infusion as well as after specific provocation with aerosolized allergen. AR was increased on days 2 and 5 after Ova challenge and had returned to baseline on day 9. AHR in isolated lungs after aerosolized or intravascular MCh strongly correlated with in vivo AR. Pretreatment of isolated lungs with the β2-agonist fenoterol diminished AR. In conclusion, this model provides new opportunities to investigate mechanisms of AHR as well as pharmacological interventions on an intact organ level.

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