Effect of saponin on the transmucosal passage of β-lactoglobulin across the proximal small intestine of normal and β-lactoglobulin-sensitised rats

The ability of saponins and glycoalkaloids to permeabilise the mammalian intestinal barrier has been previously demonstrated in vitro, leading to the hypothesis that membranolytic saponins may facilitate transfer to the tissues of otherwise excluded macromolecules. An enhanced uptake of, for instance, potentially allergenic species from the...

Hydrophobic treatment of concrete

As part of the maintenance policy of the dutch Ministry of Transport, Civil Engineering Division, hydrophobic treatment of concrete was considered as an additional protective measure against penetration of aggressive substances, for instance deicing salts in bridge decks. A set of tests was designed to determine the performance of commercial...

Organotypic models for the assessment/prediction of ocular irritation

The brief of the Organotypic Models Working Group was to review data submitted to the Interagency Regulatory Alternatives Group on the use of isolated eyes and components of the eye used to predict eye irritation potential. Data submissions were received on four test systems: the isolated rabbit eye (one submission), the isolated chicken eye ...

Foam stability related to polymer permeability. 1: Low molecular weight additives

In the production of polyethylene foams by extrusion with alkanes as a blowing agent, significant changes in the dimensions of extruded products are encountered. The dimensional stability of a foam with a structure of closed cells is improved by blending the polymer with small amounts of a low molecular weight additive. It is believed that the...

The useful application of sulphur-bound waste materials

An immobilization process is described which is based on sulphur (instead of cement) as a binding agent for the treatment of hazardous waste materials. Elemental sulphur is able to bind chemically metals such as mercury and, to a lesser extent, lead as metal sulphides. Furthermore, sulphur forms a compact solid mass that has a low permeability,...

Effects of saponins and glycoalkaloids on the permeability and viability of mammalian intestinal cells and on the integrity of tissue preparations in vitro

The effects of potato and tomato glycoalkaloids and a saponin mixture from Gypsophila were investigated in cytotoxicity studies (neutral red uptake, mitochondrial MTT reduction and release of lactate dehydrogenase), using cultured cell lines of rat and human intestinal mucosal epithelium. Experiments to assess the effects of these compounds on...

Effect of fatty acids and the aqueous diffusion barrier on the uptake and transport of polychlorinated biphenyls in Caco-2 cells

Polychlorinated biphenyls (PCBs) dissolved in dietary fat are absorbed in the gastrointestinal tract by the enterocytes in combination with the fatty acid proceeding from the lipid hydrolysis in the gut lumen. The effect of fatty acid absorption on the uptake and transport of 14 PCBs in enterocytes was studied using monolayers of the human...

Effects of condensation in clothing on heat transfer

A condensation theory is presented that enables the calculation of the rate of vapour transfer with its associated effects on temperature and total heat transfer inside a clothing ensemble consisting of underclothing, enclosed air, and outer garment. The model is experimentally tested by three experiments: (1) imperme-able garments worn by...

Capture of carbon dioxide using membrane gas absorption and reuse in the horticultural industry

The principle and engineering aspects of the membrane gas absorption process are discussed. It is shown that membrane gas absorbers have size advantages over conventional equipment. A suitable choice of absorption liquids and membranes is necessary to achieve a workable system. Significant reductions in the energy consumption of absorption...

cGMP and nitric oxide modulate thrombin-induced endothelial permeability: Regulation via different pathways in human aortic and umbilical vein endothelial cells

Previous studies have demonstrated that cGMP and cAMP reduce the endothelial permeability for fluids and macromolecules when the endothelial permeability is increased by thrombin. In this study, we have investigated the mechanism by which cGMP improves the endothelial barrier function and examined whether nitric oxide (NO) can serve as an...

Expression of cGMP-dependent protein kinase I and phosphorylation of its substrate, vasodilator-stimulated phosphoprotein, in human endothelial cells of different origin

Previous studies demonstrated that the thrombin-induced permeability of endothelial cell monolayers is reduced by the elevation of cGMP. In the present study, the presence of cGMP-dependent protein kinase (cGMP-PK) immunoreactivity and activity in various types of human endothelial cells (ECs) and the role of cGMP-PK in the reduction of thrombin...

De effectiviteit van huidbeschermingsmiddelen bij het werken metbestrijdingsmiddelen in de glastuinbouw. Deel 2: Huidbeschermendematerialen

In de glastuinbouw kan huidblootstelling aan bestrijdingsmiddelen plaatvinden, zowel tijdens het toepassing als tijdens het verrichten van werkzaamheden in het behandeld gewas. In dit rapport wordt het onderzoek beschreven naar de beschermende werking van diverse handschoen- en kledingmaterialen die commercieel verkrijgbaar zijn. Er is een...

Interlaboratory assessment of the bovine corneal opacity and permeability (BCOP) assay

A multinational interlaboratory study to investigate the bovine corneal opacity and permeability (BCOP) assay is presented. The aim of this work was to determine the capability and possible limitations of this method to predict ocular irritancy of a large set of chemicals. The assays were carried out in 12 European laboratories with different...

Vapour transfer in two-layer clothing due to diffusion and ventilation

An experiment was carried out to measure the vapour resistance of two-layer clothing ensembles as a function of air permeability of the outer layer, open or closed apertures, wind, and walking, both for the total ensemble and for the outer garment alone. Six subjects walked on a treadmill (0.0, 2.5, and 5 km.h-1) which was placed in a wind...

Assessment of dermal exposure of greenhouse workers to the pesticide bupirimate

An HPLC method was developed for estimation of dermal exposure of greenhouse workers to the pesticide bupirimate. Chromatography was performed on a cyano-modified silica column with methanol-water (6:4 by volume) containing 5 g/L ammonium sulfate as eluent. UV detection at 310 nm was used for quantitation. Dermal exposure was assessed by letting...

Regulatory functions of the coronary endothelium

In this brief review three functions of the coronary endothelium are surveyed: (a) its barrier and exchange function, (b) the prevention of coagulation and platelet aggregation, and (c) its role in vasoregulation. Impairment of these functions can occur in ischemia, hypertension, arteriosclerosis and inflammation.

Methods to improve flux during alcohol/water azeotrope separation by vapor permeation

Pervaporation and vapor permeation both offer interesting alternatives to distillation for the azeotropic dehydration of alcohols. Main reasons are considerable potential energy savings and their modular, flexible system configurations. In this paper various theoretical and practical advantages of vapor permeation compared to pervaporation are...

Clothing ventilation, vapour resistance and permeability index: Changes dus to posture, movement and wind

Using the trace gas diffusion method, the vapour resistance of three clothing ensembles (two permeable and one impermeable) was determined for four subjects, sitting, standing or walking at 0.3 and 0.9 m/s, combined with three wind speeds of <0.15, 0.7 and 4.1 m/s. Sitting increased vapour resistance by 12-36%, whereas walking and wind decreased...