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At least 217 records · Page 12Linked to original sources
PubMed1968

Failure of the Nernst-Einstein equation to correlate electrical resistances and rates of ionic self-exchange across certain fixed charge membranes.

The electrical resistances and rates of self-exchange of univalent critical ions across several types of collodion matrix membranes of high ionic selectivity were studied over a wide range of conditions. The relationship which was observed between these quantities with membranes of a certain type, namely those activated with poly-2-vinyl-N-methyl pyridinium bromide, cannot be explained on the basis of current concepts of the movement of ions across ion exchange membranes. Rates of self-exchange across these membranes were several times greater than those calculated from the electrical resistances of the membranes on the basis of an expression derived by the use of the Nernst-Einstein equation. The magnitude of the discrepancy was greatest at low concentrations of the ambient electrolyte solution and was independent of the species of both critical and noncritical ions. The data obtained with other types of collodion matrix membranes were, at least approximately, in agreement with the predictions based on the Nernst-Einstein equation. Self-exchange rates across the anion permeable protamine collodion membranes, and across the cation permeable polystyrene sulfonic acid collodion membranes, were about 20% less than those calculated from the electrical resistances. The direction and magnitude of these differences, also observed by other investigators, are qualitatively understood as an electroosmotic effect. With cation permeable membranes prepared by the oxidation of preformed collodion membranes, almost exact agreement was obtained between measured and calculated self-exchange rates; the cause of the apparent absence of an electroosmotic effect with these membranes is unknown.

Acetates↗
PubMed1990

The HAF enigma: origin and clinical consequences of the appearance of high alkaline fractions on isoelectric focusing patterns of cerebrospinal fluid.

High alkaline fractions (HAF) are irregularly present on isoelectric focusing (IEF) patterns of cerebrospinal fluid (CSF). Therefore, this phenomenon was studied retrospectively in more detail. First, the appearance of HAF in time was recorded and attempts were made to discover a relationship to the biochemical parameters of CSF. No such relationship could be established, nor could any effect of age or sex of the patients or any correlation with ambient temperature or clinical diagnosis be shown. Finally, we have shown conclusively that the cause of this random appearance of HAF can be found in the collodion bags used to concentrate the CSF. This irregular feature of the collodion bags also produces a rise in the frequency of appearance of oligoclonal bands on IEF, probably by blocking the passage of proteins. We conclude that the CSF contains protein material, and that the passage of this through the collodion filters during CSF concentration depends on the regularity of composition of the filters used, occasioning the presence (or absence) of a HAF. Of even greater consequence is the observation that when HAFs do not pass a certain collodion filter, other protein-like material can also be retained, leading to the appearance of oligoclonal bands in IEF, and causing more frequent occurrence of IEF patterns containing oligoclonal bands in CSF. Also, a slight change in the spectrum of oligoclonal bands of CSF has been found when HAFs occur. This indicates that the collodion bags do not retain all protein material in the same way.

Alkalies↗
PubMed1998

In vitro and rapid in situ transglutaminase assays for congenital ichthyoses--a comparative study.

Autosomal recessive congenital ichthyoses are a heterogeneous group of disfiguring skin diseases. They are generally characterized by variable scaling and erythroderma, and patients are frequently collodion babies at birth. Autosomal recessive congenital ichthyoses are represented in 25 of our 50 families by a defective keratinocyte transglutaminase (TGK). Pathogenic classification is difficult to assess on clinical grounds for autosomal recessive congenital ichthyoses and impossible for collodion babies. Thus, we have established a rapid TGK assay in situ on frozen skin sections using incorporation of dansyl-cadaverin to assess transglutaminase (TG) activity in combination with immunohistochemistry for TGK protein. Results were compared with TG activity levels measured in cultured differentiating keratinocytes. Sixteen of 26 patients, including a collodion baby, had strongly diminished TG activity in the cell periphery of differentiating keratinocytes and membrane-bound TG activities in vitro, ranging from 2.2 to 281.3 pmol per h mg. Nine of 26 patients, including a collodion baby, showed strong TG activity in the cell periphery of differentiating keratinocytes in situ and membrane-bound TG activities in vitro ranged from 1519 to 10917 pmol per h mg. In one case, TG assay in situ was ambiguous; however, membranous TG activity in vitro was very low at 76.9 pmol/h x mg. Our results demonstrate an excellent correlation of TG assays in vitro and in situ. In addition, we present a novel test with prognostic value for the collodion baby phenotype. This assay allows rapid pathogenic classification of autosomal recessive congenital ichthyoses with only one caveat that in rare ambiguous cases it might be necessary for proper classification to assess membrane-bound TG activity in vitro.

Animals↗
PubMed1978

A technique for the freeze-fracture of tissue culture.

Cultures of rat cerebellum grown on glass coverslips coated first with collodion and then collagen are fixed in glutaraldehyde to which ruthenium red has been added. After fixation, the collodion comes off the glass coverslips and the 3 layers: collodion-collagen-culture are handled as one piece. Following immersion in glycerol, selected areas are cut from the piece; the excised areas are a little smaller than those of the specimen carriers used in a Balzers apparatus. The ruthenium red, which stains all cells and processes, is a good indicator of specimen thickness. The explant which consists of several cell layers is redder than the peripheral monolayer of outgrowth. The square areas cut from either the explant or the outgrowth can be matched in thickness according to their shade of red. In frozen specimens, the red colour distinguishes the culture layer from the collodion-collagen support under it and from the white frost on top. During fracturing, the appearance of pink flakes on the edge of the knife indicates that the culture layer has been cleaved. The growth of cells on collodion-collagen and the fracture of the cultures with a knife, eliminate the restrictions inherent in the use of frozen 'metallic sandwiches'.

Animals↗
PubMedDate not supplied

Nitrocellulose and polyvinyl coatings prevent sperm adhesion to glass without affecting the motility of intact and demembranated human spermatozoa.

The effectiveness of several glass coating agents in preventing sperm adherence to glass surfaces for both intact and demembranated human spermatozoa was investigated. These agents included bovine serum albumin (BSA), Sigmacote, poly glu-lys, Collodion and Formvar. The presence of at least 5% of seminal plasma in sperm suspensions prevented sperm adhesion to glass surfaces. On the other hand, 56% of washed spermatozoa resuspended in an isoosmotic buffer containing 1 mg/ml of BSA attached to glass. Collodion, Formvar and Sigmacote reduced sperm attachment to glass to 2, 5 and 7%, respectively. BSA was partially effective, with 20% sperm adherence to glass, and poly glu-lys was totally ineffective. Whereas Sigmacote and BSA coatings lacked transparency, Collodion always achieved the best light transmission. Demembranated reactivated spermatozoa were all attached to glass within 90 seconds of contact. This adhesion was prevented by Collodion and Formvar. Other agents were less effective or interfered with motility. In contrast to intact spermatozoa, demembranated spermatozoa have a very low progressiveness ratio (vector speed/track speed), a wide beating amplitude and because of their whiplash flagellar movement, their motility resembles that of hamster capacitated spermatozoa.

Cell Adhesion↗
PubMed2005

Scalp electrode placement by EC2 adhesive paste in long-term video-EEG monitoring.

OBJECTIVE: To evaluate the usefulness of an adhesive paste named EC2 (Grass-Telefactor) in comparison with collodion, for scalp electrodes placement in patients with drug resistant partial epilepsy monitored by long-term video-EEG. METHODS: A total of 40 patients with drug resistant partial epilepsy participated in the study. In 20 patients, electrode placement on the scalp was made with collodion (group C) whereas in the remaining patients EC2 was used (Group P). After the electrode placement (T1) and after 24 h of recording (T2), the impedance of the electrodes was measured. Moreover, the time required to apply the electrodes and for their daily maintenance was calculated and recorded for all patients who entered the study. RESULTS: At each observation, group C showed mean values of electrode impedance significantly higher that the group P (T1: 16.8 k omega; T2: 6.5 k omega vs T1: 2.4 k omega; T2: 4.0 k omega, respectively) (P < 1 x 10(-5)). The time required to make the montage and to provide its daily maintenance was significantly shorter in group P than in group C [20.8 and 10.5 min vs 44.3 and 19.7 min, respectively (P < 1 x 10(-5))]. CONCLUSIONS: We found that the use of EC2 paste in scalp electrode attachment is less time consuming, with better recording quality as a result of lower electrode impedance values, than the use of collodion. SIGNIFICANCE: EC2 paste may substitute collodion in electrode placement for long-term video-EEG monitoring, with an optimal cost-benefit ratio in terms of recording performance, time consumption, and safety.

Collodion↗
PubMed1999

Artificial dialysis membranes: from concept to large scale production.

The development of hemodialysis from an experimental concept to a routine medical therapy is closely related to research, manufacturing and availability of dialysis membranes. Collodion, a cellulose-trinitrate derivative, was the first polymer to be used as an artificial membrane and played a central role in further investigations and applications. Basic studies on the mechanism of solute transport through membranes, like diffusion, were done by A. Fick and T. Graham using collodion as a membrane material. In vivo dialysis in animals and humans was performed with collodion by J. Abel in the USA and G. Haas in Germany. Cellophane and Cuprophan membranes replaced collodion later, because of their better performance and mechanical stability. However, due to its alleged lack of hemocompatibility, membranes made from unmodified cellulose lost their market share. They have been replaced by modified cellulosic and synthetic dialysis membranes which show a better hemocompatibility than unmodified cellulose membranes. Most of the new membrane materials are also available in high-flux modifications and for this reason suitable as well for more effective therapy modes, such as hemodiafiltration and hemofiltration. The success of hemodialysis as a routine therapy is also the success of membrane development, because both, a reproducible membrane production and an unlimited availability of dialysis membranes have increased the number of dialyzed patients to about 1 million patients worldwide in 1999.

Animals↗
PubMed1980

A method for processing paraffin sections of multilayer cultured tissue.

A simple and rapid method is described for processing histological preparations from multilayer cultures growing in plastic Petri dishes, A covering collodion film is utilized to remove the tissue from the plastic dish and transfer it onto a paper block prior to embedding in Paraplast. To avoid any disruption by the collodion of the plasticware, the cultured tissue is first immersed in a solution of collodion and absolute alcohol (1:1) and then covered with pure collodion. All steps are carried out in the cold. This procedure allows morphological, histochemical, immunofluorescent, and autoradiographic studies to be carried out on serial sections of cultured tissue.

Animals↗
PubMed1984

Controlled long-term release of small peptide hormones using a new microporous polypropylene polymer: its application for vasopressin in the Brattleboro rat and potential perinatal use.

Based on drug release by microporous hollow fibers and the recent introduction of microporous polymers, a new technique was developed for controlled delivery of peptides. Small-diameter microporous polypropylene tubing, lumen-loaded with microgram quantities of vasopressin, and coated with collodion, releases vasopressin after in vitro immersion slowly (1-100 ng/d) and constantly for months. The mechanism of pseudo-zero-order delivery is based on high adsorption of vasopressin, keeping the void volume concentration of dissolved vasopressin constant, which is consequently a constant driving force of outward diffusion. The collodion coating prevents the entry of proteinaceous compounds which would result in rapid desorption of vasopressin. The present delivery module provides a lasting release for other peptides as well (lysine-vasopressin, oxytocin, alpha-melanocyte-stimulating hormone and, to a lesser extent, Met-enkephalin). The microporous polymer-collodion device is biocompatible and, loaded with vasopressin, successfully alleviates the diabetes insipidus of Brattleboro rats deficient for vasopressin. Subcutaneous implantation normalized diuresis for a period of 60 d and constant urine vasopressin excretion is observed. When the commercially available osmotic minipump is too large for implantation, the small size of the present controlled-delivery system allows peptide treatment of young and immature laboratory rats, even if located in utero.

Animals↗
PubMed1983

Cardiopulmonary toxicity in patients with breast carcinoma during plasma perfusion over immobilized protein A. Pathophysiology of reaction and attenuating methods.

Tumoricidal reactions in dogs with spontaneous breast carcinoma occur after perfusion of plasma over protein A derived from Staphylococcus aureus and immobilized in collodion charcoal. When this treatment was extended to humans with breast cancer, hemodynamic and physiologic changes were noted. The evolution and spectrum of these reactions were evaluated during 47 plasma infusions in five patients. Initial treatment conditions consisting of rapid perfusion of plasma over high quantities of immobilized protein A were employed for 12 treatments in two patients. Within 30 minutes after treatments were begun, mean blood pressure, systemic vascular resistance, and stroke volume increased, as did heart rate, cardiac output, and rectal temperature; however, mean pulmonary artery pressure and total pulmonary resistance did not change. At 90 minutes, hypotension developed (lowest mean blood pressure was 59 +/- 14 mm Hg) that was associated with a decrease in systemic vascular resistance and total pulmonary resistance (536 +/- 66 and 146 +/- 44 dynes . second . cm-5, respectively). Cardiac output increased, tachycardia developed, stroke volume decreased, and rectal temperature increased. During the hypotensive phase, values of creatinine clearance and fractional excretion of sodium diminished. Noncardiogenic pulmonary edema appeared occasionally, with bronchospasm noted once. No hemodynamic changes were seen when saline solution was passaged over protein A immobilized in collodion charcoal or when autologous plasma was given without passage over protein A immobilized in collodion charcoal. Treatment conditions were modified by diminishing protein A quantity and plasma volume and slowing plasma perfusion rate, which resulted in significant attenuation of all cardiopulmonary responses. This report, then, defines for the first time the physiologic basis of the cardiopulmonary toxicity in humans after plasma perfusion over immobilized protein A.

Breast Neoplasms↗