Showing papers on "Glutaraldehyde published in 1991"

Lysine-enhanced glutaraldehyde crosslinking of collagenous biomaterials.

Abstract: Crosslinking of collagenous biomaterials currently employs the use of glutaraldehyde. The putative enhancement of glutaraldehyde crosslinking by lysine was investigated in three model systems: bovine pericardium, collagen membranes, and bovine serum albumin. Repetitive sequential treatment of bovine pericardium with glutaraldehyde and lysine and finally with formaldehyde produced a matrix which, by the two criteria used (shrinkage temperature and urea/SDS soluble collagen), was shown to be more highly crosslinked than pericardium fixed in glutaraldehyde alone. Essentially the same results were obtained when membranes prepared from pepsin-soluble pericardial collagen were subjected to sequential glutaraldehyde and lysine treatments, reaching shrinkage temperatures of more than 90 degrees C. Heart valves prepared from lysine-enhanced glutaraldehyde crosslinked bovine pericardium were tested in vitro in an accelerated fatigue tester and have been shown to behave satisfactorily after 300 million cycles. These additional crosslinks proved to be stable in saline at 37 degrees C. Studies on bovine serum albumin attempted to get an insight into the mechanisms of lysine enhancement of glutaraldehyde crosslinking by treating sequentially albumin with glutaraldehyde and lysine and analysis of the products by gel filtration and SDS-PAGE. These studies suggest that free amino groups exposed by proteins are initially reacted with glutaraldehyde and then bridged by the diamino compound (lysine) producing more extensive intermolecular crosslinking than glutaraldehyde alone.

Immobilization of poly(ethylene glycol) onto a poly(vinyl alcohol) hydrogel. 1. Synthesis and characterization

Abstract: PEGs were immobilized onto a poly(vinyl alcohol) hydrogel using either acetal or urethane linkages. The hydrogel was crosslinked with glutaraldehyde using MgCl 2 (water based) or toluenesulfonic acid (DMSO based) as the acid catalyst. Fully hydrated gels prepared from DMSO had a lower compression modulus than those prepared from water although both materials possessed similar water contents.

Evaluation of the genotoxic potential of glutaraldehyde.

Abstract: The cytotoxic and genotoxic effects of glutaraldehyde were studied in vitro in the human TK6 lymphoblast cell line and in primary cultures of rat hepatocytes. TK6 lymphoblasts were exposed to glutaraldehyde for 2 hr in serum-free GSH-free media. Cytotoxic effects were observed at concentrations as low as 10 microM with only 10% cell survival at 20 microM. Alkaline elution studies indicated that glutaraldehyde-induced DNA-protein crosslinking increased linearly over the concentration range from 0 to 25 microM. Glutaraldehyde-induced mutations were assessed at the thymidine kinase locus over the same concentration range and reached a plateau at 10 microM of about six times the background mutant frequency. At equivalent levels of DNA-protein crosslinks and cytolethality, glutaraldehyde was mutagenic at approximately a one-seventh lower concentration than the rodent nasal carcinogen formaldehyde (Craft et al.; Mutation Research 176:147-155, 1987). Glutaraldehyde induced a marginal increase in unscheduled DNA synthesis in the in vitro hepatocyte DNA repair assay, but only at the two highest concentrations of 50 and 100 microM, indicating the induction of some DNA excision-repair activity. These data demonstrate that glutaraldehyde exhibits DNA-reactive genotoxic activity that may involve, at least in part, DNA-protein crosslinking in these cell culture models. These findings suggest the need to examine the potential carcinogenic activity of glutaraldehyde in appropriate inhalation studies.

Microspheres prepared from temperature‐sensitive graft polymers

Abstract: Polyallylamine-graft-poly(N-isopropylacrylamide) was prepared by coupling polyallylamine with poly(N-isopropylacrylamide) (the latter with an end-standing carboxyl group). The graft polymer obtained showed a temperature-responsive phase transition under alkaline conditions, whereas the starting poly(N-isopropylacrylamide) with end-standing carboxyl group showed temperature-sensitivity under acidic conditions. With an increase in the degree of grafting the temperature-sensitivity of the polymer under weakly alkaline conditions increases. Microspheres were prepared by cross-linking the graft polymers with glutaraldehyde in water-in-oil emulsion. Trypsin immobilized to the microspheres showed temperature-responsiveness in its catalytic activity. The graft polymer can be used as a component of temperature-sensitive devices in various forms.

Biological tissue adhesion

Abstract: The invention provides a method for the application of gelatin-resorcinol aldehyde glue to a surface, wherein a solution of gelatin-resorcinol is applied to the surface to obtain a gelatin-resorcinol coated surface. Subsequently, a solution of an aldehyde is aerosolized onto the gelatin-resorcinol coated surface. The mixture of gelatin-resorcinol and the aldehyde is then allowed to polymerize on the surface. The methods of the invention may be conveniently and efficiently used to apply gelatin-resorcinol aldehyde glue to high porosity vascular prostheses, either before or after implantation, to provide improved hemostasis. The aldehydes that may be utilized according to the methods of the invention may include formaldehyde, glutaraldehyde, or a combination thereof In one embodiment of the invention, the gelatin-resorcinol aldehyde glue may be conveniently provided in a kit that includes (a) a first container of a gelatin-resorcinol solution and (b) a second container of a solution of an aldehyde, the second container including means for aerosolizing the aldehyde solution. The methods of the invention may be used for the application of gelatin-resorcinol aldehyde glue in a wide variety of surgical procedures.

Kinky microtubules : bending and breaking induced by fixation in vitro with glutaraldehyde and formaldehyde

Abstract: We have employed video-enhanced light microscopy to study alterations of the overall shape of microtubules that are produced by the aldehyde fixation methods commonly employed to study them in vitro. Changes brought about by these methods include deformation and breakage. The severity of the effects depends on the fixative employed and increases with its concentration, and with the time of fixation. The changes are observed under a variety of conditions, such as brief exposure to 3.7% formaldehyde, or somewhat longer exposure to glutaraldehyde at concentrations as low as 0.05%. The observed distortion explains why microtubules usually appear curved or sinuous in electron micrographs while appearing relatively rigid and linear in video-enhanced light microscopy. The observed breakage implies that caution must be used in inferring length distributions from measurements of aldehyde-fixed microtubules.

Antimicrobial effects from incorporation of disinfectants into gypsum casts.

Abstract: Five microorganisms--Escherichia coli, Streptococcus mutans, Staphylococcus aureus, Serratia marcescens, and Bacillus subtilis--were placed into the canine, first premolar, first molar, and second molar of sterilized quadrant addition-reaction silicone impressions. Four disinfectant solutions--iodophor, neutral glutaraldehyde, phenol, and sodium hypochlorite--were spatulated with sterilized Type IV stone and vibrated into the intentionally contaminated impressions. The casts were removed at 1 and 24 hours, and the surfaces were swabbed, plated on BHI agar, and incubated at 37 degrees C for 3 days. Colony forming units were counted. At 1 hour, only sodium hypochlorite and glutaraldehyde effectively reduced the number of bacteria to the negative control. Incorporation of sodium hypochlorite, glutaraldehyde, and iodophor into gypsum casts reduced viable bacteria to a level equal to the negative controls at 24 hours.

Disinfectants in the control of small animal ringworm due to Microsporum canis.

Abstract: Twelve disinfectant products or compounds were evaluated for their ability to kill Microsporum canis harvested from naturally infected material. The disinfectants were diluted to the concentration recommended for the disinfection of clean surfaces and the potency of each substance was determined by the degree to which it could be further diluted before losing its fungicidal action. Hypochlorite, benzalkonium chloride and glutaraldehyde based compounds were the most effective agents and phenolics, alcohol and anionic detergents were inadequate. Urea (10 mM) did not adversely affect the potency of any of the compounds.

Preparation of inner ear sensory hair bundles for high resolution scanning electron microscopy.

Abstract: Chemical fixation techniques for preservation of sensory hair bundles in the mammalian inner ear for scanning electron microscopy (SEM) are reviewed. Fixatives employed were glutaraldehyde, glutaraldehyde-picrate, glutaraldehyde-tannic acid, glutaraldehyde-formaldehyde, glutaraldehyde followed by postfixation with osmium tetroxide and the osmium thiocarbohydrazide (OTOTO) method. Dehydration was routinely accomplished with ascending grades of acetone followed by critical point drying with liquid CO2 or fluorocarbon sublimation. Specimens other than those prepared by the OTOTO method were metal coated with gold, gold-palladium or platinum. Material was viewed at high resolution (2-3 nm) in a transmission electron microscope (TEM) fitted with a scanning system and an LaB6 filament. A few specimens, which were either coated with platinum, carbon or uncoated, were examined in a field emission SEM. We have concluded that glutaraldehyde fixation followed by critical point drying with CO2 and coating with platinum gives the best general preservation of stereocilia and their cross-links for routine high resolution SEM, but that carbon-coated or uncoated specimens offer potentially better results free from metal coating artifacts when viewed with field emission SEM. These methods have enabled us to make novel observations upon the surface detail and cross-links of stereocilia which have helped considerably in understanding the mechanical properties of hair bundles particularly in relation to sensory transduction. We have found that stereocilial surface detail and cross-links are sensitive to fixation regimens. In particular they are degraded by exposure to osmium tetroxide; they are also highly labile since deleterious changes in their appearance can be detected as early as 15 minutes following death.

Synthesis of protein-coated gelatin microspheres and their use as microcarriers for cell culture. Part I. Derivatization with native collagen.

Abstract: A novel technique for the synthesis of native collagen (type I)-coated gelatin microspheres was developed using the emulsion-polymerization principle, which is realized in four steps: emulsification, separation, stabilization, and protein modification A 20% gelatin solution was emulsified in sunflower oil and the resulting beads were polymerized with glutaraldehyde The novelty of our technique consists in the protein modification step, where we derivatized the beads by saturation of the free aldehyde groups on the cross-linked gelatin in the native collagen solution (03 mg/ml in 005 M Tris, pH 86) and further stabilized the beads with sodium borohydride The resulting microspheres exhibited excellent properties as microcarriers for in vitro cell culturing using Vero cells as the model system In comparison with pure gelatin beads, the cells attached more rapidly and grew faster on native collagen-coated beads Approximately 90% of the Vero cells attached to the microcarrier after 1 h After a lag per

Strategies for improving the cytochemical and immunocytochemical sensitivity of ultrastructurally well-preserved, resin embedded biological tissue for light and electron microscopy.

Abstract: Many techniques for processing tissue into resin are available, varying from conventional room temperature to low temperature procedures. The problem is to choose an appropriate method to suit the biological specimen under study. Room temperature approaches with aldehyde and osmium fixation do not give optimal retention of immunoreactivity. Osmium can be removed from sections, but recovery of immunosensitivity is reduced. Osmium post-fixation can be omitted, but heat polymerization of resins causes tissue extraction and loss of immunoreactivity. Alternative techniques rely on the use of milder polymerization methods and avoid osmium. However, while providing an improvement, this alone is not sufficient to maximize tissue reactivity. Fixation with high concentrations of glutaraldehyde (greater than 1%) and processing into resin at either room or low temperature results in retention of similar levels of immunoreactivity. Low concentration glutaraldehyde (less than 0.2%) fixation for short periods of time (less than 60 minutes) produces improved tissue immunoreactivity and allows low concentrations of antigen at secondary sites to be detected. However, the tissue is now only minimally stabilized and is prone to extraction and conformational damage during processing. It can be partially protected by employing one of two strategies: processing at room temperature with partial dehydration (upto 70% solvent) and rapid embedding in LR White or Lowicryl K4M at 0 degrees C, or processing at progressively lower temperatures (PLT) and embedding in Lowicryl at -35/-50 degrees C. In a third strategy, specimens sensitive to very low fixative concentrations are cryo-immobilized, then resin embedded after substitution or freeze-drying (this latter method awaiting evaluation for inclusion in our strategical approach).

Antibody-or antigen-immobilized silk fibroin membrane and sensor for measuring immune

Abstract: PURPOSE:To obtain the title fibroin membrane useful for an immune sensor, capable of carrying out high-accuracy measurement free from variability by immobilizing an antibody or an antigen through covalent bond with glutaraldehyde, its polymer or cyanuric chloride, etc., as a bonding reagent. CONSTITUTION:Raw silk is immersed in 1.0wt.% aqueous solution of Marseille soap, scoured at 80 deg.C, washed with water, sericin, etc., are removed to give a fibroin raw material, which is dialyzed and desalted with flowing water, the aqueous solution of fibroin is mixed with 30wt.% based on fibroin of glycerol, the solution is cast into an acrylic plate having a divided square, dried at 20 deg.C for 10 hours, made into a coating film and released. Then the film is immersed in 80% aqueous solution of methanol at room temperature for 3 minutes to give an insoluble silk fibroin membrane. An aqueous solution of an antibody or an antigen is brought into contact with the film by using glutaraldehyde, its polymer or cyanuric chloride, etc., as a bonding reagent and the antibody or the antigen is immobilized to the film through covalent bond to give a sink fibroin membrane.

Reductive One Batch Synthesis of N-Arylpiperidines From Primary Amines and Glutaraldehyde

Abstract: The construction of the piperidine ring about an aromatic nitrogen atom, by a 5C+N reductive condensation reaction, using glutaraldehyde (pentanedial) and sodium borohydride in acidic water/methanol medium is described. The reaction is fast, affords good to excellent yields and appears insensitive to electronic effects and severe steric hindrance; it is found to be compatible with a large variety of aryl substituents, including nitro and oxo groups

Novel membrane and method of separation

Abstract: Charge compositions containing aqueous mixtures of organic oxygenates may be separated by pervaporation through a membrane assembly containing a porous ceramic support bearing as separating layer, a membrane of cured polyvinyl alcohol which has been cross-linked as with glutaraldehyde.

Glutaraldehyde resin binding system for manufacture of wood products

Abstract: This invention relates to ethyleneurea-glutaraldehyde resins, urea-ethyleneurea-glutaraldehyde resins, their synthesis, as well as their application as an adhesive for wood panel manufacture. Molar ratio of ethyleneurea to glutaraldehyde can range from 0.3 to 3.5. Urea incorporated into ethyleneurea-glutaraldehyde resin can be high as two times the moles of glutaraldehyde used in the formulation and can be introduced at any stage during the reaction course, simply post added, or any combination of the above.

Preparation and use of protein kinase C subspecies-specific anti-peptide antibodies for immunostaining.

Abstract: Publisher Summary This chapter briefly describes the preparation of protein kinase C (PKC) subspecies-specific anti-peptide antibodies and their application to histochemical studies. Variable regions of PKC subspecies, mainly C-terminal V 5 region and hinge V 3 region, are chosen to be antigenic epitopes because of their specific structures. The peptides are chemically synthesized and coupled to keyhole limpet hemocyanin (KLH) or bovine serum albumin (BSA) using m -maleimidobenzoic acid N -hydroxysuccinimide ester (MBS) 12 or glutaraldehyde. Then these complexes are employed for the immunization of rabbit with Freund's complete or incomplete adjuvant. For application of antibodies to histochemical analysis, various tissues are fixed by an appropriate fixative that maintains morphology of the cell, but does not change the antigenicity of the enzyme. When the antibody is raised against oligopeptide conjugated to the carrier protein with glutaraldehyde, Zamboni fixative containing glutaraldehyde is used for fixation. Otherwise periodate-lysine-paraformaldehyde (PLP) fixative is used. Then the sections, which are treated with PKC subspecies-specific antibody, are treated with goat anti-rabbit IgG and rabbit antiperoxidase-peroxidase complex followed by development with diaminobenzidine. For analysis by electron microscopy, the developed sections are further incubated with osmic acid. Then ultrathin sections are cut and stained with uranyl acetate.

Production of a safe, potent and immunogenic partially purified acellular pertussis vaccine using simple indigenous techniques.

Abstract: Partially purified acellular pertussis vaccine was prepared from Bordetella pertussis strains 10536, 134, Tohama and 509 using simple indigenously available techniques. The Stainer-Scholte (SS) medium with methylated-beta-cyclodextrin was the most suitable for production of acellular pertussis vaccine. For preparation of the vaccine, 5 day cultures of B. pertussis grown under stationary conditions at 35 degrees C were treated twice with ammonium sulphate and prospective protective antigens were extracted. The extracts contained pertussis toxin (PT), filamentous hemagglutinin and agglutinogens. These extracts were treated with formaldehyde and glutaraldehyde separately for detoxification of PT. The formaldehyde treatment of acellular preparations affected the potency and did not destroy the toxic effects of PT completely. Active PT was found in formaldehyde detoxified acellular pertussis vaccine (FDAPV) preparations by the Chinese hamster ovary (CHO) cell assay, the test for leucocytosis promoting factor (LPF) and the histamine sensitization (HS) test. The FDAPV preparations did not pass the mouse weight gain test (MWGT). The glutaraldehyde treatment had lesser adverse effects on potency than the formaldehyde treatment and the glutaraldehyde detoxified preparations did not show active PT by CHO cell assay, the test for LPF and the HS test. The mice tolerated high doses (up to four human doses) of GDAPV which passed the MWGT showing higher weight gains. Both FDAPV and GDAPV showed immunogenicity against agglutinogens and PT in mice. The GDAPV is a safe and potent vaccine. The total protein content of GDAPV was about 5 times lesser than that of whole cell pertussis vaccine.

Hydrolysis of plant oils by means of lipase from Rhizopus nigricans

Abstract: The crude enzyme powder from Rhizopus nigricans was immobilized by sorption and subsequent cross-linking with glutaraldehyde on collagen and polytetrafluoroethylene (PTFE) membranes Lipolytic membranes were applied to plant oils hydrolysis The comparison of the two types of membranes by calculating the time required to obtain 1 mole of free fatty acids (FFA) from 1 m2 of membrane area, indicates that hydrophobic PTFE membrane is a better one in spite of the fact that the amount of protein sorbed on PTFE membrane is about three times smaller than that for collagen membrane The hydrolysis of sunflower oil was the most efficient at the temperature of 37 °C and a pH of 7 At these conditions the specific activity after immobilization was about four times higher than that of the soluble enzyme

Immobilization of penicillin acylase in porous beads of polyacrylamide gel.

Abstract: A procedure is described for the immobilization of benzylpenicillin acylase from Escherichia coli within uniformly spherical, porous polyacrylamide gel beads. Aqueous solutions of the enzyme and sodium alginate and of acrylamide monomer, N,N'-methylene-bis-acrylamide, N,N,N,N'-tetramethylethylenediamine (TEMED) and sodium alginate are cooled separately, mixed, and dropped immediately into ice-cold, buffered calcium formate solution, pH 8.5, to give calcium alginate-coated beads. The beads are left for 30-60 min in the cold calcium formate solution for polyacrylamide gel formation. The beads are then treated with a solution of glutaraldehyde and the calcium alginate subsequently leached out with a solution of potassium phosphate. Modification of the native enzyme with glutaraldehyde results in a slight enhancement in the rate of hydrolysis of benzylpenicillin at pH 7.8 and 0.05M substrate concentration. The enzyme entrapped in porous polyacrylamide gel beads shows no measurable diffusional limitation in stirred reactors, catalyzing the hydrolysis of the substrate at a rate comparable to that of the glutaraldehyde-modified native enzyme. The immobilized enzyme preparation has been used in batch mode over 90 cycles without any apparent loss in hydrolytic activity.