Influence of environmental temperature on in vivo energy expenditure and in vitro ouabain-sensitive respiration in duodenal mucosa and liver in rats fed different levels of dietary fibre or protein

1997 ◽  
Vol 36 (4) ◽  
pp. 278-284 ◽  
Author(s):  
H. Jørgensen ◽  
X. -Q. Zhao
Keyword(s):  
Energy Expenditure ◽  
Dietary Fibre ◽  
Environmental Temperature ◽  
Duodenal Mucosa ◽  
Different Levels

Antimicrobial and antibiofilm activities of meropenem loaded-mesoporous silica nanoparticles against carbapenem-resistant Pseudomonas aeruginosa

2021 ◽  
pp. 088532822110038
Author(s):  
Mohammad Yousef Memar ◽  
Mina Yekani ◽  
Hadi Ghanbari ◽  
Edris Nabizadeh ◽  
Sepideh Zununi Vahed ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Carbapenem Resistant ◽  
Toxicity In Vitro ◽  
Different Levels

The aims of the present study were the determination of antimicrobial and antibiofilm effects of meropenem-loaded mesoporous silica nanoparticles (MSNs) on carbapenem resistant Pseudomonas aeruginosa ( P. aeruginosa) and cytotoxicity properties in vitro. The meropenem-loaded MSNs had shown antibacterial and biofilm inhibitory activities on all isolates at different levels lower than MICs and BICs of meropenem. The viability of HC-04 cells treated with serial concentrations as MICs and BICs of meropenem-loaded MSNs was 92–100%. According to the obtained results, meropenem-loaded MSNs display the significant antibacterial and antibiofilm effects against carbapenem resistant and biofilm forming P. aeruginosa and low cell toxicity in vitro. Then, the prepared system can be an appropriate option for the delivery of carbapenem for further evaluation in vivo assays.

scholarly journals In vitro life cycle of pentamidine-resistant amastigotes: stability of the chemoresistant phenotypes is dependent on the level of resistance induced.

1997 ◽  
Vol 41 (9) ◽  
pp. 1898-1903 ◽  
Author(s):  
D Sereno ◽  
J L Lemesre
Keyword(s):  
Life Cycle ◽  
Culture Conditions ◽  
Cross Resistance ◽  
Diminazene Aceturate ◽  
Drug Pressure ◽  
Mouse Macrophages ◽  
Wild Type Clone ◽  
Different Levels

Using a continuous drug pressure protocol, we induced pentamidine resistance in an active and dividing population of amastigote forms of Leishmania mexicana. We selected in vitro two clones with different levels of resistance to pentamidine, with clone LmPENT5 being resistant to 5 microM pentamidine, while clone LmPENT20 was resistant to 20 microM pentamidine. Resistance indexes (50% inhibitory concentration [IC50] after drug presure/IC50 before drug pressure) of 2 (LmPENT5) and 6 (LmPENT20) were determined after drug selection. Both resistant clones expressed significant cross-resistance to diminazene aceturate and primaquine. Pentamidine resistance was not reversed by verapamil, a calcium channel blocker known to reverse multidrug resistance (A. J. Bitonti, et al., Science 242:1301-1303, 1988; A. R. C. Safa et al., J. Biol. Chem. 262:7884-7888, 1987). No difference in the in vitro infectivity for resident mouse macrophages was observed between the wild-type clone (clone LmWT) and pentamidine-resistant clones. During in vitro infectivity experiments, when the life cycle was performed starting from the intramacrophagic amastigote stage, the drug resistance of the resulting LmPENT20 amastigotes was preserved even if the intermediate promastigote stage could not be considered resistant to 20 microM pentamidine. In the same way, when a complete developmental sequence of L. mexicana was achieved axenically by manipulation of appropriate culture conditions, the resulting axenically grown LmPENT20 amastigotes remained pentamidine resistant, whereas LmPENT5 amastigotes lost their ability to resist pentamidine, with IC50s and index of resistance values close to those for the LmWT clone. These results strongly indicate that the level of pentamidine tolerated by resistant amastigotes after the life cycle was dependent on the induced level of resistance. This fact could be significant in the in vivo transmission of drug-resistant parasites by Phlebotominae. Particular attention should be given to the finding that the emergence of parasite resistance is a potential risk of the use of inadequate doses as therapy in humans.

scholarly journals WNK4 Kinase: from structure to physiology

2021 ◽  
Author(s):  
Adrian Rafael Murillo-de-Ozores ◽  
Alejandro Rodriguez-Gama ◽  
Hector Carbajal-Contreras ◽  
Gerardo Gamba ◽  
Maria Castaneda-Bueno
Keyword(s):  
Oxidative Stress ◽  
Mouse Models ◽  
Serine Threonine Kinase ◽  
Gene Encoding ◽  
Threonine Kinase ◽  
Physiological Conditions ◽  
Different Levels ◽  
Familial Hyperkalemic Hypertension

With No Lysine (K) kinase 4 (WNK4) belongs to a serine-threonine kinase family characterized by the atypical positioning of its catalytic lysine. Despite the fact that WNK4 has been found in many tissues, the majority of its study has revolved around its function in the kidney, specifically as a positive regulator of the thiazide-sensitive NaCl cotransporter (NCC) in the distal convoluted tubule (DCT) of the nephron. This is explained by the description of gain-of-function mutations in the gene encoding WNK4 that cause Familial Hyperkalemic Hypertension (FHHt). This disease is mainly driven by increased downstream activation of the Ste20-related Proline Alanine Rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1)-NCC pathway, which increases salt reabsorption in the DCT and indirectly impairs renal K+ secretion. Here, we review the large volume of information that has accumulated about different aspects of WNK4 function. We first review the knowledge on WNK4 structure and enumerate the functional domains and motifs that have been characterized. Then, we discuss WNK4 physiological functions based on the information obtained from in vitro studies and from a diverse set of genetically modified mouse models with altered WNK4 function. We then review in vitro and in vivo evidence on the different levels of regulation of WNK4. Finally, we go through the evidence that has suggested how different physiological conditions act through WNK4 to modulate NCC activity.

Human duodenal mucosal brush border Na+/H+ exchangers NHE2 and NHE3 alter net bicarbonate movement

2001 ◽  
Vol 281 (1) ◽  
pp. G159-G163 ◽  
Author(s):  
Maltin Repishti ◽  
Daniel L. Hogan ◽  
Vijaya Pratha ◽  
Laura Davydova ◽  
Mark Donowitz ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Brush Border ◽  
Polyclonal Antibodies ◽  
Duodenal Mucosa ◽  
Transport Processes ◽  
Apical Surface ◽  
Luminal Perfusion ◽  
Significant Step

The proximal duodenal mucosa secretes HCO[Formula: see text] that serves to protect the epithelium from injury. In isolated human duodenal enterocytes in vitro, multiple luminal membrane proteins are involved in acid/base transport. We postulated that one or more isoforms of the Na+/H+ exchanger (NHE) family is located on the apical surface of human duodenal mucosal epithelial cells and thereby contributes to duodenal mucosal HCO[Formula: see text] transport. Duodenal biopsies were obtained from human volunteers, and the presence of NHE2 and NHE3 was determined by using previously characterized polyclonal antibodies (Ab 597 for NHE2 and Ab 1381 for NHE3). In addition, proximal duodenal mucosal HCO[Formula: see text] transport was measured in humans in vivo in response to luminal perfusion of graded doses of amiloride; 10−5–10−4 M amiloride was used to inhibit NHE2 and 10−3 M amiloride to inhibit NHE3. Both NHE2 and NHE3 were localized principally to the brush border of duodenal villus cells. Sequential doses of amiloride resulted in significant, step-wise increases in net duodenal HCO[Formula: see text] output. Inhibition of NHE2 with 10−5 M and 10−4 M amiloride significantly increased net HCO[Formula: see text] output. Moreover, there was an additional, equivalent increase ( P < 0.05) in duodenal HCO[Formula: see text] output with 10−3 M amiloride, which inhibited NHE3. We conclude that 1) NHE2 and NHE3 are localized principally to the brush border of human duodenal villus epithelial cells; 2) sequential inhibition of NHE2 and NHE3 isoforms resulted in step-wise increases in net HCO[Formula: see text]output; 3) NHE2 and NHE3 participate in human duodenal villus cell HCO[Formula: see text] transport; and 4) the contribution of NHE-related transport events should be considered when studying duodenal HCO[Formula: see text] transport processes.

scholarly journals Imaging Expression of Cytosine Deaminase-Herpes Virus Thymidine Kinase Fusion Gene (CD/TK) Expression with [124I]FIAU and PET

2002 ◽  
Vol 1 (1) ◽  
pp. 153535002002000 ◽  
Author(s):  
Trevor Hackman ◽  
Michail Doubrovin ◽  
Julius Balatoni ◽  
Tatiana Beresten ◽  
Vladimir Ponomarev ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Thymidine Kinase ◽  
Enzyme Assay ◽  
Fusion Gene ◽  
Cytosine Deaminase ◽  
Prodrug Activation ◽  
Wide Range ◽  
Different Levels

Double prodrug activation gene therapy using the Escherichia coli cytosine deaminase (CD)herpes simplex virus type 1 thymidine kinase ( HSV1-tk) fusion gene ( CD/TK) with 5-fluorocytosine (5FC), ganciclovir (GCV), and radiotherapy is currently under evaluation for treatment of different tumors. We assessed the efficacy of noninvasive imaging with [124I]FIAU (2′-fluoro-2′-deoxy-1-β-d-arabinofuranosyl-5-iodo-uracil) and positron emission tomography (PET) for monitoring expression of the CD/TK fusion gene. Walker-256 tumor cells were transduced with a retroviral vector bearing the CD/TK gene (W256CD/TK cells). The activity of HSV1-TK and CD subunits of the CD/TK gene product was assessed in different single cell-derived clones of W256CD/TK cells using the FIAU radiotracer accumulation assay in cells and a CD enzyme assay in cell homogenates, respectively. A linear relationship was observed between the levels of CD and HSV1-tk subunit expression in corresponding clones in vitro over a wide range of CD/TK expression levels. Several clones of W256CD/TK cells with significantly different levels of CD/TK expression were selected and used to produce multiple subcutaneous tumors in rats. PET imaging of HSV1-TK subunit activity with [124I]FIAU was performed on these animals and demonstrated that different levels of CD/TK expression in subcutaneous W256CD/TK tumors can be imaged quantitatively. CD expression in subcutaneous tumor sample homogenates was measured using a CD enzyme assay. A comparison of CD and HSV1-TK subunit enzymatic activity of the CD/TK fusion protein in vivo showed a significant correlation. Knowing this relationship, the parametric images of CD subunit activity were generated. Imaging with [124I]FIAU and PET could provide pre- and posttreatment assessments of CD/TK-based double prodrug activation in clinical gene therapy trials.

Correlation of Structural Changes at Different Levels of the Jejunal Villus with Positive and Negative Net Water Transport in Vivo and in Vitro

1975 ◽  
Vol 53 (3) ◽  
pp. 439-450 ◽  
Author(s):  
T. F. McElligott ◽  
I. T. Beck ◽  
P. K. Dinda ◽  
S. Thompson
Keyword(s):  
Epithelial Cells ◽  
Water Content ◽  
Water Transport ◽  
Structural Changes ◽  
Morphological Changes ◽  
Sugar Transport ◽  
Apical Part ◽  
Different Levels

Experiments were done for identification and localization of certain structural changes at different levels of jejunal villus of the hamster during positive and negative water transport across the intestine in vivo and in vitro. Positive transport occurred when the mucosal surface of the intestine was bathed (in vitro experiments) or perfused (in vivo experiments) with isotonic Krebs–Ringer bicarbonate solution containing 10 mM glucose, and negative water transport was achieved by rendering this solution hypertonic with 150 mM mannitol. Results indicate that during positive net water transport, the intestine in vivo transported more fluid and exhibited a more conspicuous dilatation of the lateral intercellular spaces (L.I.S.) than did the in vitro preparation. Dilatation of the L.I.S. in both preparations was present only in the apical part of the villus, suggesting that this is the principal site of water absorption. When the mucosal solution was made hypertonic with mannitol, the L.I.S. in the in vivo intestine totally collapsed, whereas in the in vitro intestine these spaces remained open very slightly. These morphological changes correspond well with our finding that in the presence of the hypertonic mucosal solution there was a greater net negative water transport in vivo than in vitro. Incubation of the intestine in the isotonic mucosal solution produced subnuclear swelling of the mid-villus epithelial cells, and this morphological change was associated with an increase in the water content of the tissue. Perfusion of the in vivo intestine with the isotonic solution produced neither the swellings nor the increase in water content of the tissue. In the presence of hypertonic mucosal solution there was a water loss from the tissue both in vivo and in vitro, and these swellings were not observed. These results are discussed in relation to intestinal sugar transport and to the maturity of the epithelial cells, and it is concluded that transport studies on in vitro preparations may provide valid information on a qualitative basis, if not on a strictly quantitative basis.

scholarly journals Dietary fibre and the importance of the gut microbiota in feline nutrition: a review

2014 ◽  
Vol 27 (2) ◽  
pp. 295-307 ◽  
Author(s):  
Kristel Rochus ◽  
Geert P. J. Janssens ◽  
Myriam Hesta
Keyword(s):  
Dietary Fibre ◽  
Large Scale ◽  
Domestic Cat ◽  
Microbiota Composition ◽  
Domestic Cats ◽  
Beneficial Effects ◽  
Plant Fibre ◽  
Potential Benefits

Domestic cats are obligate carnivores and in this light hindgut fermentation has been considered unimportant in this species. However, a diverse microbiota has been found in the small and large intestines of domestic cats. Additionally, in vitro and in vivo studies support the hypothesis that microbial fermentation is significant in felines with potential benefits to the host. Results on microbiota composition and microbial counts in different regions of the feline gastrointestinal tract are compiled, including a description of modulating host and technical factors. Additionally, the effects of dietary fibre supplementation on the microbiota composition are described. In a second section, in vitro studies, using inocula from fresh feline faeces and focusing on the fermentation characteristics of diverse plant substrates, are described. In vivo studies have investigated the effects of dietary fibre on a broad range of physiological outcomes. Results of this research, together with studies on effects of plant fibre on colonic morphology and function, protein and carbohydrate metabolism, and the effects of plant fibre on disease conditions that require a decrease in dietary protein intake, are shown in a third section of the present review. Conclusively, for fructans and beet pulp, for example, diverse beneficial effects have been demonstrated in the domestic cat. Both dietary fibre sources are regularly used in the pet food industry. More research is warranted to reveal the potential benefits of other fibre sources that can be used on a large scale in feline diets for healthy and diseased cats.

scholarly journals Nanomaterials induce different levels of oxidative stress, depending on the used model system: Comparison of in vitro and in vivo effects

2020 ◽  
Author(s):  
Isabel Karkossa ◽  
Anne Bannuscher ◽  
Bryan Hellack ◽  
Wendel Wohlleben ◽  
Julie Laloy ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cells ◽  
Alveolar Macrophages ◽  
Model System ◽  
Alveolar Epithelial Cells ◽  
Model Systems ◽  
Alveolar Epithelial ◽  
Different Levels

Abstract Background The immense variety and constant development of nanomaterials (NMs) raise the demand for a facilitated risk assessment, for which knowledge on NMs mode of actions (MoAs) is required. For this purpose, a comprehensive data basis is of paramountcy that can be obtained using omics. Furthermore, the establishment of suitable in vitro test systems is indispensable to follow the 3R concept and to master the high number of NMs. In the present study, we aimed at comparing NM effects in vitro and in vivo using a multi-omics approach. We applied an integrated data evaluation strategy based on proteomics and metabolomics to four silica NMs and one titanium dioxide-based NM. For in vitro investigations, alveolar epithelial cells and alveolar macrophages were treated with different doses of NMs, and the results were compared to effects on rat lungs after short-term inhalations and instillations at varying doses with and without a recovery period.Results Since the production of reactive oxygen species (ROS) is described to be a critical biological effect of NMs, and enrichment analyses confirmed oxidative stress as a significant effect upon NM treatment in vitro in the present study, we focused on different levels of oxidative stress. Thus, we found opposite changes for proteins and metabolites that are related to the production of reduced glutathione in alveolar epithelial cells and alveolar macrophages, illustrating that NMs MoAs depend on the used model system. Interestingly, in vivo, pathways related to inflammation were affected to a greater extent than oxidative stress responses. Hence, the assignment of the observed effects to the levels of oxidative stress was different in vitro and in vivo as well. However, the overall classification of “active” and “passive” NMs was consistent in vitro and in vivo.Conclusions The consistent classification indicates both tested cell lines to be suitable for NM toxicity assessment even though the induced levels of oxidative stress strongly depend on the used model systems. Thus, the here presented results highlight that model systems need to be carefully revised to decipher the extent to which they can replace in vivo testing.

NADPH Cytochrome P-450 Oxidoreductase and Susceptibility to Ketoconazole

1998 ◽  
Vol 42 (7) ◽  
pp. 1756-1761 ◽  
Author(s):  
K. Venkateswarlu ◽  
Diane E. Kelly ◽  
Nigel J. Manning ◽  
Steven L. Kelly
Keyword(s):  
Ergosterol Biosynthesis ◽  
Squalene Epoxidase ◽  
Wild Type ◽  
Gene Encoding ◽  
Nadph Cytochrome ◽  
Cytochrome P 450 ◽  
Different Levels ◽  
Donor System

ABSTRACT The phenotype of a strain of Saccharomyces cerevisiaecontaining a disruption of the gene encoding NADPH cytochrome P-450 oxidoreductase (CPR) was quantified biochemically and microbiologically, as were those of various transformants of this strain after expression of native CPR, cytochrome P-45051 (CYP51), and a fusion protein of CYP51-CPR (FUS). Only a 4-fold decrease in ergosterol biosynthesis was observed for the cpr strain, but ketoconazole sensitivity increased 200-fold, indicating hypersensitivity to the alternative electron donor system incpr strains. Both phenotypes could be reversed in transformants expressing the CPR and FUS, indicating the availability of the CPR in FUS as well as the expressed native CPR for monoxygenase-associated reactions. The complementation of function was observed both in vitro and in vivo for the monoxygenases squalene epoxidase, CYP51, and CYP61 in the ergosterol biosynthesis pathway with which CPR is coupled. Overexpression of CYP51 and FUS produced different levels of ketoconazole resistance in wild-type cells, indicating that the availability of CPR may limit the potential of overproduction of CYP51 as a mechanism of resistance to azole antifungal agents.

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