The potential of microdialysis to estimate rifampicin concentrations in the lung of guinea pigs

Optimised pre-clinical models are required for TB drug development to better predict the pharmacokinetics of anti-tuberculosis (anti-TB) drugs to shorten the time taken for novel drugs and combinations to be approved for clinical trial. Microdialysis can be used to measure unbound drug concentrations in awake freely moving animals in order to describe the pharmacokinetics of drugs in the organs as a continuous sampling technique. The aim of this work was to develop and optimise the microdialysis methodology in guinea pigs to better understand the pharmacokinetics of rifampicin in the lung. In vitro experiments were performed before progressing into in vivo studies because the recovery (concentration of the drug in the tissue fluid related to that in the collected dialysate) of rifampicin was dependent on a variety of experimental conditions. Mass spectrometry of the dialysate was used to determine the impact of flow rate, perfusion fluid and the molecular weight cut-off and membrane length of probes on the recovery of rifampicin at physiologically relevant concentrations. Following determination of probe efficiency and identification of a correlation between rifampicin concentrations in the lung and skeletal muscle, experiments were conducted to measure rifampicin in the sacrospinalis of guinea pigs using microdialysis. Lung concentrations of rifampicin were estimated from the rifampicin concentrations measured in the sacrospinalis. These studies suggest the potential usefulness of the microdialysis methodology to determine drug concentrations of selected anti-TB drugs to support new TB drug development.

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Dietary compounds as potential modulators of microRNA expression in psoriasis

Therapeutic Advances in Chronic Disease ◽

10.1177/2040622319864805 ◽

2019 ◽

Vol 10 ◽

pp. 204062231986480 ◽

Cited By ~ 13

Author(s):

Hristina Kocic ◽

Giovanni Damiani ◽

Bojana Stamenkovic ◽

Michael Tirant ◽

Andrija Jovic ◽

...

Keyword(s):

Vitamin D ◽

Omega 3 ◽

Experimental Conditions ◽

Keratinocyte Proliferation ◽

Methyl Donors ◽

Beneficial Effects ◽

Small Noncoding Rnas ◽

The Impact

Nutrigenomic DNA reprogramming in different chronic diseases and cancer has been assessed through the stimulation of gene expression and mRNA synthesis versus DNA silencing by CpG DNA modification (methylation); histone modification (acetylation, methylation) and expression of small noncoding RNAs, known as microRNAs (miRNAs). With regard to the specific nutrigenomic effects in psoriasis, the influence of specific diets on inflammatory cell signaling transcriptional factors such as nuclear factor (NF)-κB and Wnt signaling pathways, on disease-related specific cytokine expression, pro/antioxidant balance, keratinocyte proliferation/apoptosis and on proliferation/differentiation ratio have been documented; however, the influence of dietary compounds on the balance between ‘good and bad’ miRNA expression has not been considered. This review aims to summarize knowledge about aberrant microRNAs expression in psoriasis and to emphasize the potential impact of some dietary compounds on endogenous miRNA synthesis in experimental conditions in vivo and in vitro. Among the aberrantly expressed miRNAs in psoriasis, one of the most prominently upregulated seems to be miR-21. The beneficial effects of phenolic compounds (curcumin and resveratrol), vitamin D, methyl donors, and omega-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) are discussed. Highly expressed miR-155 has been downregulated by flavonoids (through a quercetin-rich diet) and by vitamin D. Quercetin has been effective in modulating miR-146a. On the other hand, downregulated miR-125b expression was restored by vitamin D, Coenzyme Q10 and by microelement selenium. In conclusion, the miRNA profile, together with other ‘omics’, may constitute a multifaceted approach to explore the impact of diet on psoriasis prevention and treatment.

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The Anti-Porcine Parvovirus Activity of Nanometer Propolis Flavone and Propolis FlavoneIn VitroandIn Vivo

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2015/472876 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 4

Author(s):

Xia Ma ◽

Zhenhuan Guo ◽

Zhiqiang Shen ◽

Yonglu Liu ◽

Jinliang Wang ◽

...

Keyword(s):

Guinea Pigs ◽

Hemagglutination Inhibition ◽

Antiviral Drug ◽

Porcine Parvovirus ◽

Porcine Kidney ◽

High Concentration ◽

Before And After ◽

The Impact

Objectives. The present study was conducted to evaluate the activity of nanometer propolis flavone (NPF) on inhibiting porcine parvovirus (PPV)in vitroandin vivo.Methods.In vitro, the effect of NPF on cellular infectivity of PPV was carried out before and after adding drug and simultaneous adding and PPV after being mixed.In vivo, the anti-PPV effect of NPF in guinea pigs was performed.Results. The results showed that NPF could significantly inhibit PPV infecting porcine kidney- (PK-) 15 cells compared with propolis flavone (PF), and the activity of NPF was the best in preadding drug pattern. NPF at high and medium doses was able to observably restrain PPV copying in lung, gonad, blood, and spleen, decrease the impact of PPV on weight of guinea pigs, and improve hemagglutination inhibition (HI) of PPV in serum. In addition, it could also increase the contents of IL-2 and IL-6 in serum after PPV challenge.Conclusion. These results indicated that NPF could significantly improve the anti-PPV activity of PF, and its high concentration possessed the best efficacy. Therefore, NPF would be expected to be exploited into a new-style antiviral drug.

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Comparison of the In Vitro and In Vivo Electrochemical Performance of Bionic Electrodes

Micromachines ◽

10.3390/mi13010103 ◽

2022 ◽

Vol 13 (1) ◽

pp. 103

Author(s):

Alexander R. Harris ◽

Carrie Newbold ◽

Dimitra Stathopoulos ◽

Paul Carter ◽

Robert Cowan ◽

...

Keyword(s):

Electrochemical Performance ◽

Electrochemical Impedance ◽

Fibrous Tissue ◽

In Vitro Testing ◽

Experimental Conditions ◽

Electrode Implantation ◽

Electrochemical Response ◽

The Impact

The electrochemical performance of platinum electrodes was assessed in vitro and in vivo to determine the impact of electrode implantation and the relevance of in vitro testing in predicting in vivo behaviour. A significant change in electrochemical response was seen after electrode polarisation. As a result, initial in vitro measurements were poor predictors of subsequent measurements performed in vitro or in vivo. Charge storage capacity and charge density measurements from initial voltammetric measurements were not correlated with subsequent measurements. Electrode implantation also affected the electrochemical impedance. The typically reported impedance at 1 kHz was a very poor predictor of electrode performance. Lower frequencies were significantly more dependent on electrode properties, while higher frequencies were dependent on solution properties. Stronger correlations in impedance at low frequencies were seen between in vitro and in vivo measurements after electrode activation had occurred. Implanting the electrode increased the resistance of the electrochemical circuit, with bone having a higher resistivity than soft tissue. In contrast, protein fouling and fibrous tissue formation had a minimal impact on electrochemical response. In vivo electrochemical measurements also typically use a quasi-reference electrode, may operate in a 2-electrode system, and suffer from uncompensated resistance. The impact of these experimental conditions on electrochemical performance and the relevance of in vitro electrode assessment is discussed. Recommended in vitro testing protocols for assessing bionic electrodes are presented.

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THE CHEMOSUPPRESSION OF CHEMOTAXIS

Journal of Experimental Medicine ◽

10.1084/jem.124.2.209 ◽

1966 ◽

Vol 124 (2) ◽

pp. 209-226 ◽

Cited By ~ 172

Author(s):

Peter A. Ward

Keyword(s):

Guinea Pigs ◽

Systemic Treatment ◽

Rabbit Serum ◽

Arthus Reaction ◽

Methyl Prednisolone ◽

Vascular Walls ◽

Drug Concentrations ◽

Circulating Antigen

The effects of various drugs on chemotaxis of polymorphonuclear leukocytes (PMN's) in vitro and in vivo have been studied. Response of rabbit PMN's in vitro to the chemotactic factor of rabbit serum, consisting of an activated protein-protein complex of the fifth and sixth (and probably seventh) components of complement (C'), is suppressed by hydrocortisone, methyl prednisolone, and chloroquine. Drug concentrations causing 50% inhibition of chemotaxis in vitro were found to be: hydrocortisone, 2.9 x 10–4 M; methly prednisolone, 1.2 x 10–4 M; and chloroquine 8.5 x 10–6 M. The hydrocortisone effect on PMN's appeared to be irreversible, since washing of the cells did not restore their chemotactic response. 2, 4-Dinitrophenol (DNP), vitamin A, and endotoxin did not inhibit chemotaxis. Hydrocortisone and chloroquine did block serum C' activity in vitro, but only at substantially higher concentrations. Using the reversed passive Arthus reaction in guinea pigs as a model for chemotaxis in vivo, systemic treatment of animals with hydrocortisone or chloroquine inhibited development of the vasculitis. Circulating antigen and C' were fixed in vascular structures, and serum C' was not perceptibly altered. Nevertheless, PMN infiltrates failed to occur. Local administration of hydrocortisone also prevented influx of PMN's in the Arthus reaction, in spite of the fact that immune reactants were found fixed in the vascular walls. Systemic treatment of guinea pigs with DNP did not diminish the intensity of the Arthus reactions. Phagocytosis of zymosan particles by rabbit PMN's was inhibited by hydrocortisone, methyl prednisolone, and chloroquine, but not by DNP or endotoxin. The concentrations of drugs inhibitory in phagocytosis were substantially higher than those required for inhibition of chemotaxis in vitro. These findings suggest that hydrocortisone and chloroquine inhibit the inflammatory process by preventing the response of leukocytes to chemotactic stimuli.

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Neuroinflammatory changes increase the impact of stressors on neuronal function

Biochemical Society Transactions ◽

10.1042/bst0370303 ◽

2009 ◽

Vol 37 (1) ◽

pp. 303-307 ◽

Cited By ~ 17

Author(s):

Alessia Piazza ◽

Marina A. Lynch

Keyword(s):

Neurodegenerative Diseases ◽

Amyloid Β ◽

Amyloid Β Peptide ◽

Experimental Conditions ◽

Age Related ◽

Increased Risk ◽

Aβ Amyloid ◽

The Impact

In the last few years, several research groups have reported that neuroinflammation is one feature common to several neurodegenerative diseases and that similar, although perhaps less profound, neuroinflammatory changes also occur with age. Age is the greatest risk factor in many neurodegenerative diseases, and the possibility exists that the underlying age-related neuroinflammation may contribute to this increased risk. Several animal models have been used to examine this possibility, and it is now accepted that, under experimental conditions in which microglial activation is up-regulated, responses to stressors are exacerbated. In the present article, these findings are discussed and data are presented from in vitro and in vivo experiments which reveal that responses to Aβ (amyloid β-peptide) are markedly up-regulated in the presence of LPS (lipopolysaccharide). These, and previous findings, point to a vulnerability associated with inflammation and suggest that, even though inflammation may not be the primary cause of neurodegenerative disease, its treatment may decelerate disease progression.

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Superoxide, Xanthine Oxidase and Platelet Reactions: Further Studies on Mechanisms by which Oxidants Influence Platelets

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650190 ◽

1981 ◽

Vol 45 (03) ◽

pp. 290-293 ◽

Cited By ~ 9

Author(s):

Peter H Levine ◽

Danielle G Sladdin ◽

Norman I Krinsky

Keyword(s):

Superoxide Dismutase ◽

Cytochrome C ◽

Xanthine Oxidase ◽

Direct Effect ◽

Platelet Function ◽

Experimental Conditions ◽

Release Reaction

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

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Inhibition of Human and Animal Platelet Adhesiveness to Glass Bead Columns by Adenosine, Dipyridamole, Chlorpromazine and Acetylsalicylic Acid

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648055 ◽

1976 ◽

Vol 36 (02) ◽

pp. 401-410 ◽

Cited By ~ 6

Author(s):

Buichi Fujttani ◽

Toshimichi Tsuboi ◽

Kazuko Takeno ◽

Kouichi Yoshida ◽

Masanao Shimizu

Keyword(s):

Guinea Pig ◽

Acetylsalicylic Acid ◽

Guinea Pigs ◽

Glass Bead ◽

Animal Species ◽

Inhibitory Effect ◽

Rabbit Platelet ◽

Platelet Adhesiveness

SummaryThe differences among human, rabbit and guinea-pig platelet adhesiveness as for inhibitions by adenosine, dipyridamole, chlorpromazine and acetylsalicylic acid are described, and the influence of measurement conditions on platelet adhesiveness is also reported. Platelet adhesiveness of human and animal species decreased with an increase of heparin concentrations and an increase of flow rate of blood passing through a glass bead column. Human and rabbit platelet adhesiveness was inhibited in vitro by adenosine, dipyridamole and chlorpromazine, but not by acetylsalicylic acid. On the other hand, guinea-pig platelet adhesiveness was inhibited by the four drugs including acetylsalicylic acid. In in vivo study, adenosine, dipyridamole and chlorpromazine inhibited platelet adhesiveness in rabbits and guinea-pigs. Acetylsalicylic acid showed the inhibitory effect in guinea-pigs, but not in rabbits.

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Desmopressin (DDAVP) Enhances Platelet Adhesion to the Extracellular Matrix of Cultured Human Endothelial Cells through Increased Expression of Tissue Factor

Thrombosis and Haemostasis ◽

10.1055/s-0038-1656088 ◽

1997 ◽

Vol 77 (05) ◽

pp. 0975-0980 ◽

Cited By ~ 23

Author(s):

Angel Gálvez ◽

Goretti Gómez-Ortiz ◽

Maribel Díaz-Ricart ◽

Ginés Escolar ◽

Rogelio González-Sarmiento ◽

...

Keyword(s):

Extracellular Matrix ◽

Endothelial Cells ◽

Tissue Factor ◽

Platelet Adhesion ◽

Umbilical Vein ◽

Procoagulant Activity ◽

Experimental Conditions ◽

Chromogenic Assay

SummaryThe effect of desmopressin (DDAVP) on thrombogenicity, expression of tissue factor and procoagulant activity (PCA) of extracellular matrix (ECM) generated by human umbilical vein endothelial cells cultures (HUVEC), was studied under different experimental conditions. HUVEC were incubated with DDAVP (1, 5 and 30 ng/ml) and then detached from their ECM. The reactivity towards platelets of this ECM was tested in a perfusion system. Coverslips covered with DD A VP-treated ECMs were inserted in a parallel-plate chamber and exposed to normal blood anticoagulated with low molecular weight heparin (Fragmin®, 20 U/ml). Perfusions were run for 5 min at a shear rate of 800 s1. Deposition of platelets on ECMs was significantly increased with respect to control ECMs when DDAVP was used at 5 and 30 ng/ml (p <0.05 and p <0.01 respectively). The increase in platelet deposition was prevented by incubation of ECMs with an antibody against human tissue factor prior to perfusion. Immunofluorescence studies positively detected tissue factor antigen on DDAVP derived ECMs. A chromogenic assay performed under standardized conditions revealed a statistically significant increase in the procoagulant activity of the ECMs produced by ECs incubated with 30 ng/ml DDAVP (p <0.01 vs. control samples). Northern blot analysis revealed increased levels of tissue factor mRNA in extracts from ECs exposed to DDAVP. Our data indicate that DDAVP in vitro enhances platelet adhesion to the ECMs through increased expression of tissue factor. A similar increase in the expression of tissue factor might contribute to the in vivo hemostatic effect of DDAVP.

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Applicability of Instability Index for In vitro Protein Stability Prediction

Protein and Peptide Letters ◽

10.2174/0929866526666190228144219 ◽

2019 ◽

Vol 26 (5) ◽

pp. 339-347 ◽

Cited By ~ 4

Author(s):

Dilani G. Gamage ◽

Ajith Gunaratne ◽

Gopal R. Periyannan ◽

Timothy G. Russell

Keyword(s):

Protein Stability ◽

Caulobacter Crescentus ◽

Effect Of Temperature ◽

Instability Index ◽

Dipeptide Composition ◽

Experimental Conditions ◽

The Stability ◽

Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

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