Effects of osmotic gradients on water and solute transport: in vivo studies in rat duodenum and ileum.

We examined effects of luminal osmolality on net water and solute movements in rat duodenum and ileum. Solutions of sodium chloride (permeating solute) or mannitol (nonpermeating solute) at hypo-, iso-, or hyperosmotic concentrations were recirculated through in situ segments. Luminal osmolality increased towards that of plasma with hyposmotic solutions of both solutes. With isosmotic solutions, luminal osmolality did not change with sodium chloride, but increased with mannitol. With hyperosmotic solutions, luminal osmolality always decreased toward that of plasma with sodium chloride; with mannitol, however, decreases were significant only when initial concentrations were above 400 mosmol/kg. The decrease in osmolality of hyperosmotic sodium chloride resulted from sodium absorption and water secretion. Thus, both hypo- and hyperosmotic solutions of sodium chloride adjusted toward isomolality with plasma by the usual mechanisms of water and solute movement. With mannitol, however, osmotic adjustment of hypertonic luminal contents was restricted or even absent due to movement of sodium down its concentration gradient and reduced hydraulic conductivity of the gut.

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Comparison of the intestinal absorption and bioavailability of γ-tocotrienol and α-tocopherol: in vitro, in situ and in vivo studies

Biopharmaceutics & Drug Disposition ◽

10.1002/bdd.1790 ◽

2012 ◽

Vol 33 (5) ◽

pp. 246-256 ◽

Cited By ~ 30

Author(s):

Bilal S. Abuasal ◽

Hisham Qosa ◽

Paul W. Sylvester ◽

Amal Kaddoumi

Keyword(s):

Intestinal Absorption ◽

In Vivo Studies

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Fabrication of Injectable, Porous Hyaluronic Acid Hydrogel Based on an In-Situ Bubble-Forming Hydrogel Entrapment Process

Polymers ◽

10.3390/polym12051138 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1138

Author(s):

Lixuan Wang ◽

Shiyan Dong ◽

Yutong Liu ◽

Yifan Ma ◽

Jingjing Zhang ◽

...

Keyword(s):

Hyaluronic Acid ◽

Regenerative Medicine ◽

In Vivo Studies ◽

Injectable Hydrogels ◽

Cell Behaviors ◽

Porous Architecture ◽

In Situ Hydrogel

Injectable hydrogels have been widely applied in the field of regenerative medicine. However, current techniques for injectable hydrogels are facing a challenge when trying to generate a biomimetic, porous architecture that is well-acknowledged to facilitate cell behaviors. In this study, an injectable, interconnected, porous hyaluronic acid (HA) hydrogel based on an in-situ bubble self-generation and entrapment process was developed. Through an amide reaction between HA and cystamine dihydrochloride activated by EDC/NHS, CO2 bubbles were generated and were subsequently entrapped inside the substrate due to a rapid gelation-induced retention effect. HA hydrogels with different molecular weights and concentrations were prepared and the effects of the hydrogel precursor solution’s concentration and viscosity on the properties of hydrogels were investigated. The results showed that HA10-10 (10 wt.%, MW 100,000 Da) and HA20-2.5 (2.5 wt.%, MW 200,000 Da) exhibited desirable gelation and obvious porous structure. Moreover, HA10-10 represented a high elastic modulus (32 kPa). According to the further in vitro and in vivo studies, all the hydrogels prepared in this study show favorable biocompatibility for desirable cell behaviors and mild host response. Overall, such an in-situ hydrogel with a self-forming bubble and entrapment strategy is believed to provide a robust and versatile platform to engineer injectable hydrogels for a variety of applications in tissue engineering, regenerative medicine, and personalized therapeutics.

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Antibacterial properties and in vivo studies of tannic acid-stabilized silver–halloysite nanomaterials

Clay Minerals ◽

10.1180/clm.2020.17 ◽

2020 ◽

Vol 55 (2) ◽

pp. 112-119

Author(s):

Anna Stavitskaya ◽

Christina Shakhbazova ◽

Yulia Cherednichenko ◽

Läysän Nigamatzyanova ◽

Gölnur Fakhrullina ◽

...

Keyword(s):

Tannic Acid ◽

Antibacterial Properties ◽

Halloysite Nanotubes ◽

In Vivo Studies ◽

Negative Effects ◽

Antibacterial Performance ◽

Synthesis Strategy ◽

Clay Nanotubes

AbstractTannic acid-stabilized silver nanoparticles were synthesized in situ on halloysite clay nanotubes. The synthesis strategy included simple steps of tannic acid adsorption on clay nanotubes and further particle formation from silver salt solution. Pristine halloysite nanotubes as well as amino-modified clays were used for silver stabilization in water or ethanol. The materials were tested for antibacterial performance using three different methods. All of the materials produced showed antimicrobial activity. The pristine halloysite-based material with ~5 nm particles produced using ethanol as the solvent and tannic acid as the reducing agent showed the greatest antibacterial activity against Serratia marcescens. The materials were tested in vivo on Caenorhabditis elegans nematodes to ensure their safety, and they showed no negative effects on nematode growth and life expectancy.

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In Situ Cross-linking Hydrogel as a Vehicle for Retinal Progenitor Cell Transplantation

Cell Transplantation ◽

10.1177/0963689719825614 ◽

2019 ◽

Vol 28 (5) ◽

pp. 596-606 ◽

Cited By ~ 7

Author(s):

Jeayoung Park ◽

Petr Baranov ◽

Aybike Aydin ◽

Hany Abdelgawad ◽

Deepti Singh ◽

...

Keyword(s):

In Vivo Studies ◽

Subretinal Space ◽

Cross Linking ◽

Post Transplantation ◽

Ki 67 ◽

Retinal Progenitor ◽

Stem Cell Delivery

One of the current limitations of retinal transplantation of stem cells as well as other cell types is the dispersion of cells from the injection site (including loss of cells into the vitreous chamber) and low survival after transplantation. Gelatin-hydroxyphenyl propionic acid (Gtn-HPA) conjugate is a biodegradable polymer that can undergo covalent cross-linking in situ, allowing for injection of incorporated cells through a small caliber needle followed by gel formation in vivo. We tested the hypothesis that Gtn-HPA hydrogel supports survival and integration of retinal progenitor cells (RPCs) post-transplantation. In vitro compatibility and in vivo graft survival were assessed by mixing an equal volume of Gtn-HPA conjugate and RPC suspension and triggering enzyme-mediated gelation, using minute amounts of horseradish peroxidase and peroxide. Immunocytochemistry showed >80% survival of cells and minimal apoptosis for cells incorporated into Gtn-HPA, equivalent to controls grown on fibronectin-coated flasks. RPCs undergoing mitosis were seen within the three-dimensional Gtn-HPA hydrogel, but the percentage of Ki-67-positive cells was lower compared with the monolayer controls. For in vivo studies, gel–cell mixture or cell suspension in saline was trans-sclerally injected into the left eye of female Long Evans rats immunosuppressed with cyclosporine A. Grafts survived at the 1 week time point of the study, with Gtn-HPA-delivered grafts showing less inflammatory response demonstrated by anti-leukocyte staining. More eyes in the gel–cell mixture group showed surviving cells in the subretinal space compared with saline-delivered controls, while the number of cells surviving per graft was not significantly different between the two groups. This work demonstrates an injectable in situ cross-linking hydrogel as a potential vehicle for stem cell delivery in the retina.

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FORMULATION AND EVALUATION OF NOVEL IN SITU GEL OF LAFUTIDINE FOR GASTRO RETENTIVE DRUG DELIVERY

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2018.v11i8.25582 ◽

2018 ◽

Vol 11 (8) ◽

pp. 88

Author(s):

Sindhoor S M ◽

Sneh Priya ◽

Amala Maxwell

Keyword(s):

Drug Release ◽

Imaging Study ◽

Lag Time ◽

In Vivo Studies ◽

In Vitro Drug Release ◽

In Situ Gel ◽

Drug Content

Objective: The aim of the present study was to formulate and evaluate the novel in situ gel of lafutidine for gastroretentive drug deliveryMethods: A gastroretentive in situ gel of lafutidine was formulated by pH-triggered ionic gelation method using different concentrations of gelling polymer such as sodium alginate, gellan gum, and xanthum gum. Prepared formulations were evaluated for viscosity, density, buoyancy lag time and buoyancy duration, and drug content. In vitro drug release studies of all formulations were also performed. In vivo fluorescence imaging study was conducted for optimized formulation and compared with control.Results: The concentration of gelling agents and release retardant polymers significantly affected viscosity, floating behavior, and in vitro drug release of the formulations. The pH and drug content were found in the range of 6.72–7.20 and 88.74–95.33%, respectively. Floating lag time was <2 min; duration of floating was more than 12 h. Minimum and maximum in vitro drug release were found to be for formulation F9 (51.74%) and F1 (82.76%), respectively, at the end of 12 h. The drug was released from the all the formulations in a sustained manner. In vivo studies confirmed the gastroretention of the formulation in mice stomach for 8 h. Stability studies indicated that the there was no significant change in the visual appearance, floating behavior, and drug content.Conclusion: The gastroretentive in situ gel system, prolonged the gastric residence time, thereby targeting site-specific drug release in the upper gastrointestinal tract.

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Rapid conversion of the ester prodrug abiraterone acetate results in intestinal supersaturation and enhanced absorption of abiraterone: In vitro, rat in situ and human in vivo studies

European Journal of Pharmaceutics and Biopharmaceutics ◽

10.1016/j.ejpb.2015.01.001 ◽

2015 ◽

Vol 90 ◽

pp. 1-7 ◽

Cited By ~ 39

Author(s):

Jef Stappaerts ◽

Sophie Geboers ◽

Jan Snoeys ◽

Joachim Brouwers ◽

Jan Tack ◽

...

Keyword(s):

Abiraterone Acetate ◽

In Vivo Studies ◽

Enhanced Absorption ◽

Ester Prodrug ◽

Rapid Conversion

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Embolism resistance in petioles and leaflets of palms

Annals of Botany ◽

10.1093/aob/mcz104 ◽

2019 ◽

Vol 124 (7) ◽

pp. 1173-1183 ◽

Cited By ~ 3

Author(s):

Thaise Emilio ◽

Laurent J Lamarque ◽

José M Torres-Ruiz ◽

Andrew King ◽

Guillaume Charrier ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Xylem Embolism ◽

Phylogenetic Relatedness ◽

X Ray ◽

Xylem Pressure ◽

Palm Species ◽

Embolism Resistance ◽

Increasing Temperature

Abstract Background and aims Hydraulic studies are currently biased towards conifers and dicotyledonous angiosperms; responses of arborescent monocots to increasing temperature and drought remain poorly known. This study aims to assess xylem resistance to drought-induced embolism in palms. Methods We quantified embolism resistance via P50 (xylem pressure inducing 50 % embolism or loss of hydraulic conductivity) in petioles and leaflets of six palm species differing in habitat and phylogenetic relatedness using three techniques: in vivo X-ray-based microcomputed tomography, the in situ flow centrifuge technique and the optical vulnerability method. Key results Our results show that P50 of petioles varies greatly in the palm family, from −2.2 ± 0.4 MPa in Dypsis baronii to −5.8 ± 0.3 MPa in Rhapis excelsa (mean ± s.e.). No difference or weak differences were found between petioles and leaf blades within species. Surprisingly, where differences occurred, leaflets were less vulnerable to embolism than petioles. Embolism resistance was not correlated with conduit size (r = 0.37, P = 0.11). Conclusions This study represents the first estimate of drought-induced xylem embolism in palms across biomes and provides the first step towards understanding hydraulic adaptations in long-lived arborescent monocots. It showed an almost 3-fold range of embolism resistance between palm species, as large as that reported in all angiosperms. We found little evidence for hydraulic segmentation between leaflets and petioles in palms, suggesting that when it happens, hydraulic segregation may lack a clear relationship with organ cost or replaceability.

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The Development of an In Situ Assay for bFGF Release

MRS Proceedings ◽

10.1557/proc-331-187 ◽

1993 ◽

Vol 331 ◽

Author(s):

S. K. Hobbs ◽

L. M. Periolat ◽

L. G. Cima ◽

M. Nugent ◽

M. Leunig ◽

...

Keyword(s):

In Vivo Studies ◽

Dorsal Skinfold Chamber ◽

Control Growth ◽

Vessel Growth ◽

And Control ◽

Tissue Reactivity ◽

In Situ Assay

AbstractThere is a need for an in situ assay to quantify tissue reactivity to sustained release of bFGF to better understand and control growth factor-induced angiogenesis. To this end we have adapted the alginate/heparin-sepharose release system for use in the mouse dorsal skinfold chamber. A mathematical model was used to predict the time dependence of bFGF release as a function of bFGF loading, heparin concentration, and device geometry. The model predictions agreed well with previously reported in vitro data. In vivo studies to correlate blood vessel growth as a function of release rate are in progress.

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