Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Collodion”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed2003

The release profiles of intact and enzymatically digested hyaluronic acid from semisolid formulations using multi-layer membrane system.

A multi-layer membrane system was used to measure in vitro release of hydrophilic macromolecules such as hyaluronic acid (HA) from semisolid formulations. One enzymatically digested HA-derivative with molecular mass of 22 kDa (HA-D) and 1200 kDa intact HA (HA) were incorporated into three semisolid formulations: water-containing hydrophilic ointment (WHO), amphiphilic cream (AC) and water-containing wool wax alcohol ointment (WWO). Because of the high hydrophilic properties of HA-D and HA, the artificial model membranes consisted of collodion as the matrix and glycerol as the hydrophilic acceptor phase. The area under the concentration-time curve and the mean dissolution time were used as a quantitative parameter to characterise the rate and extent of release in vitro. This study showed that the HA-D and HA release as hydrophilic substances from WHO was higher than both from AC and WWO. It was observed that 83% of HA-D1 was released from WHO after 2 h; in contrast, only 10% was released from 2% HA from the same vehicle during the same time. In conclusion, the in vitro availability of enzymatically digested HA-D was higher for WHO than for the other formulations, AC and WWO. Similarly, the availability of HA-D was higher than that of HA from the same formulations.

Buffers↗
PubMed1985

Protein A and staphylococcal products in neoplastic disease.

Tumoricidal responses and tumor regressions have been observed after plasma perfusion over Staphylococcus aureus Cowan I (SAC), or purified protein A immobilized on solid supports. This system was initially studied in a single human patient and then extended to dogs with spontaneous mammary carcinoma, an excellent model of human breast cancer. In the single patient and dogs with mammary tumors, perfusion of plasma over protein A bearing staphylococcus resulted in tumor necrosis and tumor regression. Tumor reduction or growth retardation with similar perfusion systems has been noted in various feline and rodent tumor models. Tumoricidal responses were also observed in canine tumors after perfusion over commercial protein A which was immobilized in a collodion charcoal matrix (PACC). These responses were amplified when a subtherapeutic and nontoxic dose of cytarabine was given after perfusion. Similar tumor reduction in murine and feline tumor models has been noted after perfusion of autologous serum over protein A immobilized on various other solid supports. The PACC perfusion system was extended to five consecutive patients with advanced breast adenocarcinoma. Four of five patients showed tumor regression after perfusion of small volumes of autologous or homologous plasma over PACC. Patients also experienced pyrexia, nausea, vomiting, and significant cardiopulmonary toxicity. Detailed hemodynamic studies of these effects showed that the major pathophysiology involved a decline in total peripheral resistance associated with an increase in cardiac output. With reduction of immobilized protein A quantity and diminution in plasma perfusion rate, the cardiopulmonary toxicity associated with treatments was diminished. Chemotherapy given as FAC to a single patient shortly after concluding perfusion therapy resulted in rapid regression of residual large tumor masses. Studies focusing on the mechanism of the tumoricidal responses have examined changes in sera after incubation or perfusion over immobilized SAC or PACC. Major findings include (1) the identification of protein A leaching from PACC and SAC after serum perfusion and appearing in the effluent as Clq binding oligomers composed predominantly of IgG and protein A but also containing IgA, IgM and C3 with a molecular weight range of 600,000 to 2,000,000; (2) the identification of C3a anaphylatoxins in serum perfused over PACC or SAC; (3) the recognition that several enterotoxins, in particular enterotoxin B are present in commercial protein A preparation.(ABSTRACT TRUNCATED AT 400 WORDS)

Brain Neoplasms↗
PubMed1981

Fast stages of photoelectric processes in biological membranes. I. Bacteriorhodopsin.

Bacteriorhodopsin-containing fragments of Halobacterium halobium membrane (bacteriorhodopsin sheets) were incorporated into a lecithin-impregnated collodion film, and fast stages of flash-induced electrogenesis were measured by two electrodes separated by this film. It is found that a single turnover of bacteriorhodopsin results in an electrogenic response composed of three main stages of the following tau: the first less than 200 ns, the second 15 - 70 microseconds and the third 10 ms. The second and third phases are of the same direction as an electric response to continuous illumination, whereas the first one is oppositely directed. The microseconds and ms stages were shown to correlate, in the first approximation, with formation and decomposition of the bacteriorhodopsin intermediate absorbing with 412 nm, respectively. Both the second and third phases of the photoelectric response are sums of at least two exponents. The third stage is specifically inhibition by La3+ ions which are also shown to decrease the rate of regeneration of the original bacteriorhodopsin absorbing at 570 nm from the intermediate absorbing at 412 nm. Acidification of the medium induces parallel inhibition of the second and third phases and of formation of the intermediate absorbing at 412 nm as if protonation of a group with pK = 3.6 were responsible for this inhibition. The first (opposite) phase survives acidification. It even increases at pH lower than 1.5. At such a low pH, one can show a good correlation of decays of photopotential and of a bacteriorhodopsin bathointermediate. The decays are biphasic (tau 1 = 200 microseconds and tau 2 = 2 ms), formation of both the photopotential and the bathointermediate being faster than 200 ns. At higher pH, when a three-phase photoelectric response is revealed, decay of the formed electric potential difference gives the average tau value of about 1 s. It can be accelerated by compounds that increase ionic conductance of biomembranes. At pH below 4, fluoride is found to completely inhibit the second and third phases, so that only the first phase is observed. The results are discussed in terms of a scheme postulating that the first electrogenic phase is a result of translocation of the protonated Schiff base inside the membrane due to a light-induced conformation change in retinal or protein. The second and third phases are explained by H+ transfer from the Schiff base to the outer membrane surface and from inner (cytoplasmic) surface of membrane to the Schiff base, respectively.

Bacteriorhodopsins↗
PubMed1981

Fast stages of photoelectric processes in biological membranes. II. Visual rhodopsin.

The functioning of visual rhodopsin as a photoelectric generator has been demonstrated with a direct method. Photoreceptor discs were incorporated into a phospholipid-impregnated collodion film. Illumination of the resulting system with continuous light was found to induce formation of an electric potential (the disc-free side positive) that was measured with two electrodes separated by the film. A photopotential exceeding 40 mV was shown. It dissipated before the light source was switched off. A 15 ns 530-nm laser flash induced the formation of a photopotential of up to 35 mV whose appearance was preceded with a small oppositely directed electrogenic phase. This "negative" photoresponse took less than 200 ns. The "positive" photoresponse was composed of at least two phases (t 1/2 about 500 microseconds and several milliseconds). The latter was shown to correlate with formation of metarhodopsin II. A 347-nm laser flash added after a 530-nm flash resulted in a photoelectric effect similar to that initiated by 530-nm flash but of opposite direction. The 347-nm response was completely abolished by hydroxylamine preventing the accumulation of metarhodopsin II. The response at 530 nm proved to be hydroxylamine-resistant. Both the amplitude and the decay time of the flash-induced potential were maximal in the response to the first flash, each subsequent flash being less effective than the preceding one. Flashes were found to cause acceleration of the photopotential decay. The latter effect proved to be due to a increase of membrane conductance that developed faster than in 50 ms. Addition of 11-cis retinal after illumination improved the amplitude of the photoresponse but not the conductance. The light-induced increase in conductance was insensitive to hydroxylamine. It is suggested that a function of visual rhodopsin consists of generating a potential difference across the photoreceptor disc membrane which responds with a increase in membrane permeability to a rise of the membrane potential. A possible role of an electric break-down of the membrane, induced by the rhodopsin-generated local or partially delocalized electric field has been discussed.

Animals↗
PubMed1977

Artificial liver: the effect of ACAC microencapsulated charcoal hemoperfusion on fulminant hepatic failure.

Control trials and statistical analysis were carried out to assess the effects of albumin-collodion microencapsulated activated charcoal (ACAC) hemoperfusion on fulminant hepatic coma. A rat model of galactosamine induced fulminant hepatic coma was used. Rats which did not recover died at 3.0+/-0.6 days after galactosamine injection. Those which survived this period recovered. Forty-eight hours after galactosamine injection, a test group of 21 rats were treated with 1 hour hemoperfusion and compared with an untreated group of 23 rats. 71.4% of the treated group survived as compared to 30.4% of the untreated rats. Statistical analysis (t test) shows a significant increase in recovery for the treated group (less than 0.01). Biochemical and histological results will be discussed.

Albumins↗
PubMed1968

Solid ion-exchange electrode selective for calcium ion.

A calcium-selective electrode with solid ion exchanger was prepared from a solution of the calcium salt of a dialkylphosphoric acid in collodion. The electrode responds rapidly and reproducibly to activity of calcium ion and demonstrates a selective response for calcium ion in the presence of alkaline earth and alkali metal cations.

Calcium↗
PubMed1975

In situ production of a synthetic barrier dressing for burn wounds in rats.

We describe the in situ production of a burn wound dressing applied to eschar that completely isolates burned tissue from contamination with Pseudomonas aeruginosa. Anesthetized, adult rats were subjected to a scald burn over 10% of their body surfaces. One-half hour later a test dressing presumed to be a barrier to bacterial contamination of the wound was applied to the burned surface. Tannic acid, vaseline, ethyl linoleate, collodion, and polyhydroxethylmethacrylate (PHEMA) were evaluated. Each agent was applied directly to the burned surface. A solid film of the PHEMA was produced on the eschar by addition of solvent and a powdered form of the polymer. The surface of each synthetic dressing was contaminated 30 min after application by the addition of 10(8) P. aeruginosa. Also, a control set of rats was burned and their eschars were directly contaminated without application of the test dressing. Seven days later the contaminated muscle under the burned area in 10 control rats had P. aeruginosa counts of 10(7) to 10(8) per g of muscle (wet weight). Of the materials tested, only PHEMA consistently acted as an effective barrier dressing, reducing bacteria in the muscle to undetectable levels in 11 of 14 tests. It was also possible to treat contaminated eschar through this synthetic dressing by topical application of antibiotics to the barrier surface. The results suggest a novel clinical approach in which a barrier dressing could be used to isolate a burn eschar from environmental and subject contamination until the wound site is ready for grafting.

Acrylic Resins↗
PubMed1995

Modelling of drug penetration into human skin using a multilayer membrane system.

In this article, a new in vitro model system is presented with a multilayer membrane system serving as acceptor. Matrix-stabilized membranes are applied with dodecanol as lipid and collodion as matrix. Using the drug dithranol it was shown that the acceptor system can be varied over a wide range by changing the dodecanol content of the membranes and by addition of the hydrophilic substance propylene glycol to the membranes. It was demonstrated that the variability of the acceptor system can be used to adapt the penetration profiles of dithranol in a six-layer membrane system to those in excised human skin. It is shown that it is possible to study the penetration of dithranol from different semisolid formulations using the 'adapted' model system.

Anthralin↗
PubMed1983

Long-term and constant release of vasopressin from Accurel tubing: implantation in the Brattleboro rat.

A long-lasting and constant release of vasopressin in serum solution (in vitro) for periods up to 50 days can be obtained by the use of small-diameter microporous Accurel polypropylene tubing, filled with vasopressin and covered with collodion. The potency of the preparation is shown in vivo after subcutaneous implantation in the adult vasopressin-deficient Brattleboro rat, for which normal levels of urine production and osmolality were achieved at least for 1 month. The possible use of this method for other peptides and its application in small or immature laboratory animals and in fetuses is emphasized.

Animals↗
PubMed1995

Enzyme replacement therapy in ENU2 phenylketonuric mice using oral microencapsulated phenylalanine ammonia-lyase: a preliminary report.

The presence of an extensive enterorecirculation of amino acids between the intestine and the body allows the removal of systemic phenylalanine in PKU rats by oral microencapsulated phenylalanine ammonia lyase. The work presented in this article has the main goal of assessing the feasibility of yeast phenylalanine ammonia-lyase (PAL) loaded collodion microcapsules in reducing elevated plasma phenylalanine concentrations to standard levels in genetically mutated PKU mice, within a 30 day time frame. The distinguishing aspect from previous studies lies in the available animal model. Rather than artificial induction of elevated phenylalanine plasma levels, the mice representing the human phenylketonuric condition, are mutated strains which are deficient in the enzyme phenylalanine hydroxylase. The first in vivo study established a method for orally feeding microcapsules, both control and enzyme loaded, over 30 consecutive days, by mixing with soft, unripened cheese. Under this unique regime a decrease of 51.3% +/- 9.02% in phenylalanine plasma levels was observed after 23 days. Reduction in the phenylalanine plasma levels to within the desired maintenance range of 250-1000 umol/L was observed in 2 out of 4 PAL treated mice, with only 50% of the PAL dose used in previous rat studies by Chang's group. The second animal study confirmed the finding in the first in vivo study that there is no significant decrease in the plasma phenylalanine levels within the first seven days. This may be due to the severely deteriorated physical condition of the ENU mice used, the PAL enzyme preparations available or the fact that normal mice contain 10 times the amount of phenylalanine hydroxylase as compared with humans, thus requiring larger doses of PAL in order to be effective in a shorter time span.

Administration, Oral↗
PubMedDate not supplied

Hemodialysis 1912-1945: no medical technology: before its time: part I.

W. J. Kolff's development of the first clinical dialysis device was a remarkable achievement in the absence of any previous extensive laboratory or experimental data. An examination of the four decades before the emergence of dialysis provides a unique occasion to see how science and medical technology evolved relative to the growth of complex bodies of knowledge. Dialysis emerged from the development of six distinct scientific and medical knowledge bases: 1) mechanical forces (diffusion and convection); 2) anticoagulants (hirudin and heparin); 3) membranes (collodion and cellophane); 4) kidney physiology; 5) serum and urine analysis; and 6) clinical perceptions and treatment. Each area progressed independent of the others and at different rates of speed. Basic sources of information were found in Index Medicus, Biological Abstracts, and Chemical Abstracts between 1900 and 1945. These references were surveyed for articles and the main reference works that delineated historic stages in each. With a critical mass of knowledge, Kolff envisioned a technologic solution to specific clinical needs. His work is illustrative of how medical science and practitioners work in a dynamic manner drawing from a wide array of scientific areas to meet clinical needs.

Cellophane↗
PubMed1977

[Synthesis and physico-chemical properties of the antihypertensive agent urapidil (author's transl)].

6-(3-[4-(o-Methoxyphenyl)-1-piperazinyl]-propylamino)-1,3-dimethyluracil (Urapidil, Ebrantil) is a new antihypertensive agent whose synthesis and physico-chemical properties are described. The size of the permeation constant KD of the passive transport through collodion-lecithin membranes and the value of the partition coefficient P in the neutral area indicate a good absorption and uniform distribution of the substance in the organism.

Antihypertensive Agents↗
PubMedDate not supplied

In vitro and clinical studies of the removal of cortisol, thyroxine, insulin, and thyroid-stimulating hormone by coated charcoal haemoperfusion.

This study was carried out to assess the removal of free and protein-bound hormones by ACAC (albumin-collodion coated activated charcoal) and uncoated activated charcoal. Adsorptions of cortisol, thyroxine, insulin and thyroid-stimulating hormone from aqueous solution or plasma were studied in vitro. The effects of ACAC haemoperfusion on the systemic levels of these hormones were also studied in patients. Studies in vitro show that both types of charcoal efficiently remove hormones from protein-free solution. Removal of hormones from plasma depends on the proportions of free and protein-bound hormones in the plasma. Clinical results show only a low clearance for hormones which are strongly protein bound. The results suggested that the removal of hormones by activated charcoal is largely dependent on (1) the affinity of charcoal for the particular hormone, (2) molecular size of the hormone and (3) the degree of protein binding of the hormone. The results also show that ultrathin membrane coating does not alter the adsorption of the activated charcoal compared with uncoated charcoal.

Adsorption↗
PubMedDate not supplied

[Kinetics of the generation of a photo-induced electric potential in chromatophores of photosynthetizing bacteria].

Flash-induced formation of an electric potential difference (delta psi) was monitored by a direct method in chromatophores associated with the collodion phospholipid membrane. In Rhodospirillum rubrum and Rhodopseudomonas sphaeriodes chromatophores, the kinetics of delta psi generation exhibit fast (tau less than or equal to 0.3 microseconds) and slow (tau congruent to 200 microseconds) phases, the latter observed in the presence of exogenous quinones. Comparison of the kinetic and potentiometric characteristics of the process with those of electron transport reactions suggests that the fast phase of delta psi rise is due to charge separation between the primary electron donor, P870, and primary electron acceptor QIFe; the slow phase, which is inhibited by o-phenanthroline, is due to electron donation from QIFe to the secondary acceptor, quinone QII. The kinetics of delta psi decay include components arising form the recombination of primary separated charges (tau congruent to 30 ms) and from the passive discharge of the membrane (tau congruent to 400 ms; tau congruent to 1400 ms). From a redox titration of the photo-induced electric signal and the photo-induced absorption changes of P870 at different pH meanings, the value of pK for the primary acceptor FeQI was found to be 7.4 in Rps. sphaeroides chromatophores. In Chromatium minutissimum, a phase ( tau congruent to 20 microseconds) was observed in addition to those seen in Rps. sphaeroids and R. rubrum which was explained by the reduction of P890+ from the high potential cytochrome c555. Possible distribution of the electron transport components in the chromatophore membrane are discussed.

Bacterial Chromatophores↗
PubMed1977

Herpes simplex: treatment today.

Past and current therapies for recurrent mucocutaneous herpes simplex infections are reviewed. At present, no topical or systemic therapy has been proved safe and effective in scientific double-blind studies. Recent treatment with flexible collodion is discussed.

BCG Vaccine↗
PubMed1999

Simple sutureless skin graft fixation.

A simple method to enhance split-thickness skin graft immobilization without sutures is described. The method uses collodion to secure a mesh gauze to the adjacent skin preventing skin graft dislodgment. The technique is rapid and efficient.

Collodion↗
PubMed2000

Glucocerebrosidase gene mutations in patients with type 2 Gaucher disease.

Gaucher disease, the most common lysosomal storage disorder, results from the inherited deficiency of the enzyme glucocerebrosidase. Three clinical types are recognized: type 1, non-neuronopathic; type 2, acute neuronopathic; and type 3, subacute neuronopathic. Type 2 Gaucher disease, the rarest type, is progressive and fatal. We have performed molecular analyses of a cohort of 31 patients with type 2 Gaucher disease. The cases studied included fetuses presenting prenatally with hydrops fetalis, infants with the collodion baby phenotype, and infants diagnosed after several months of life. All 62 mutant glucocerebrosidase (GBA) alleles were identified. Thirty-three different mutant alleles were found, including point mutations, splice junction mutations, deletions, fusion alleles and recombinant alleles. Eleven novel mutations were identified in these patients: R131L, H255Q, R285H, S196P, H311R, c.330delA, V398F, F259L, c.533delC, Y304C and A190E. Mutation L444P was found on 25 patient alleles. Southern blots and direct sequencing demonstrated that mutation L444P occurred alone on 9 alleles, with E326K on one allele and as part of a recombinant allele on 15 alleles. There were no homozygotes for point mutation L444P. The recombinant alleles that included L444P resulted from either reciprocal recombination or gene conversion with the nearby glucocerebrosidase pseudogene, and seven different sites of recombination were identified. Homozygosity for a recombinant allele was associated with early lethality. We have also summarized the literature describing mutations associated with type 2 disease, and list 50 different mutations. This report constitutes the most comprehensive molecular study to date of type 2 Gaucher disease, and it demonstrates that there is significant phenotypic and genotypic heterogeneity among patients with type 2 Gaucher disease. Hum Mutat 15:181-188, 2000. Published 2000 Wiley-Liss, Inc.

Alleles↗
PubMed2000

Drug penetration as studied by noninvasive methods: fourier transform infrared-attenuated total reflection, fourier transform infrared, and ultraviolet photoacoustic spectroscopy.

The penetration of the drugs dithranol and methoxsalen from semisolid Vaseline formulation into an artificial dodecanol-collodion membrane was followed by three spectroscopic methods; they are, step-scan Fourier transform infrared (FTIR) photoacoustic spectroscopy (PAS) with phase modulation, FTIR-attenuated total reflection (FTIR-ATR), and ultraviolet (UV) PAS. The uptake of the drug in the membrane was quantified by monitoring the dependence of an appropriate drug band on the penetration time. The PAS experiments were carried out with various modulation frequencies for generating various sampling depths. Based on Fick's second law, the diffusion coefficient was derived by numerical fitting of the experimental data. It appears that the diffusion coefficient for the drug in the membrane depends on the distance. The comparative studies demonstrate that FTIR-ATR is favored for permeation studies, whereas the PAS techniques are capable of providing the drug penetration profile in the membrane. Thus, extended experimental data are available for new insight into the penetration process. However, because of the photacoustic cells at hand, PAS is only suitable for in vitro studies.

Administration, Topical↗