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At least 1,225 records · Page 68Linked to original sources
PubMed1979

Immune activation by T-independent antigens: lack of effect of macrophage depletion on the immune response to TNP-LPS, PVP and dextran.

Carrageenan, a sulphated polysaccharide, and rabbit anti-mouse macrophage serum, were used to inhibit macrophage function in BALB/c mice as well as to deplete macrophages from spleen cell cultures in an attempt to determine the requirement for macrophages in the immune response to several thymus-independent antigens. Carrageenan inhibited macrophage function and was cytotoxic at low concentrations. The ability of T and B lymphocytes to undergo mitogen-induced proliferation in the presence of PHA and PLS, respectively, was not affected by in vitro exposure of lymphoid cells to carrageenan. BALB/c mice injected with carrageenan demonstrated a suppressed immune response to SRBC, a thymus-dependent antigen, but not to E. coli LPS, polyvinyl-pyrrolidone or dextran B-1355S, all of which are known to be thymus independent antigens. The sensitivity of the in vivo immune response to SRBC after depletion of macrophages by carrageenan treatment was confirmed in vitro using the Marbrook--Diener culture system. The in vitro immune response to TNP-LPS was unaffected by either carrageenan treatment or treatment of BALB/c spleen cells with AMS and complement. The results of experiments which utilized the two anti-macrophage reagents, carrageenan and AMS, both in vivo and in vitro systems, suggest that the immune response to thymus-independent antigens does not require the participation of macrophages.

Animals↗
PubMed1977

Immunologic characteristics in relation to high and low leukemogenic activity of radiation leukemia virus variants. I. Cellular analysis of immunosuppression.

Infection of adult C57BL/6 mice with variants of the radiation leukemia virus resulted in variable leukemia incidence. One variant, designated D-RadLV, induced lymphatic leukemia in 0 to 25% of mice after virus inoculation directly into the thymus of young adult mice. The leukemia incidence could be increased to 80 to 100% by host exposure to x-rays. The second variant, A-RadLV, induced lymphatic leukemia in 80 to 100% of similarly inoculated mice without the need for additional radiation treatment. Adult mice were inoculated with D-radLV or A-RadLV. Both variants reduced the immune response to sheep erythrocytes whereas only D-RadLV had an immunosuppressive effect after immunization with a thymus-independent immunogen polyvinyl-pyrrolidone (PVP). Results of transfer experiments indicated that the immunosuppressive effects were expressed at the immunocompetent cell level. Thymus-derived cells were affected by A-RadLV since their immunocompetent function was impaired, whereas D-RadLV affected the marrow cell population of immunocytes. Exposure of D-RadLV-inoculated mice to x-rays induced functional impairment of both thymus and marrow cells. Since the radiation leukemia virus induces "T" lymphatic leukemia it could be proposed that the initial tropism of the virus to thymocytes would lead to high leukemia induction potential, whereas virus tropism to bone marrow cells would yield a low leukemia incidence. The coleukemogenic effect of x-rays could perhaps be related with its capacity to alter and introduce a change in virus-lymphoid cells interaction.

Animals↗
PubMed1988

[Polyvinylpyrrolidone iodine--its significance in dermatology].

In an open comparative study, 40 patients suffering from pyoderma, combustion (1st and 2nd degrees), leg ulcer, or inflammatory white atrophy were treated with a topical preparation containing either polyvinyl pyrrolidone iodine or neomycin. Both preparations were well-tolerated. There was no local hypersensibility. With regard to the therapeutic effect, we did not observe any differences between the two groups of patients. We discuss the properties, modes of action, and contraindications, as well as the possible systemic influences of topically applied PVP iodine.

Administration, Topical↗
PubMed1988

[Preparation and testing of polymer drugs. 4. Water-soluble polymer drugs with a base of vinylpyrrolidone-maleic acid anhydride-copolymers].

Watersoluble polymeric drugs were synthesized on the basis of alternating copolymer of 1-vinyl-2-pyrrolidone and maleic anhydride. Benzocain served as model drug. The drug was bound directly as well as about epsilon-aminocapronic acid as spacer. The pancreatin catalyzed hydrolysis of these polymeric drugs was studied. No hydrolysis was noted, if the drug is directly bound on the copolymer. The polymeric drug with the epsilon-aminocapronic acid as spacer showed a small release. Possible reasons for these facts are discussed.

Aminocaproic Acid↗
PubMed1987

Combination effect of penetration enhancers and propylene glycol on in vitro transdermal absorption of insulin.

In vitro transdermal absorption of insulin was improved when the penetration enhancers Azone, N-methyl-2-pyrrolidone (NMP) or dimethyl sulfoxide (DMSO) were incorporated in propylene glycol (PG) formulations of the drug. Maximum penetration efficacy depended on optimal concentrations of both the enhancer and PG. Azone and NMP showed maximum efficacy at 0.1% and 12.0% concentration, respectively. In both cases, the optimum concentration of PG was 40.0%. The enhancing ability of DMSO was much lower in comparison with the other two enhancers.

Administration, Cutaneous↗
PubMed1988

Adsorption of proteins from artificial tear solutions to contact lens materials.

A series of polymers and copolymers of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) were synthesized in order to find surfaces that would adsorb minimal amounts of protein. The adsorption of albumin, lysozyme and immunoglobulin G from a three-way mixture of these proteins in isotonic buffered saline to the polymers was measured using 125I-labeled proteins. Apparently high protein uptake on copolymers rich in HEMA was found to be due to sorption of unbound 125I by the polymers. 125I sorption by the polymers was minimized by dialysis of the protein solution to remove unbound 125I iodide and inclusion of 0.01 M sodium iodide to block uptake of residual 125I iodide. Using these improved protocols, minimal total protein uptake was observed on copolymers containing 50% or more HEMA. The majority of adsorbed protein on all p(MMA-HEMA) polymers was albumin. Total protein uptake was greatest on pMMA. Commercial contact lenses composed of copolymers of HEMA and N-vinyl pyrrolidone (NVP) or acrylamide (AAm) adsorbed small amounts of all proteins whereas copolymers of methacrylic acid (MAAc) and HEMA adsorbed much larger quantities of lysozyme. These results indicate that protein uptake by contact lens materials varies greatly with polymer composition. Artifactually high "adsorption" can occur if precautions are not taken to prevent uptake of unbound 125I.

Acrylates↗
PubMed1988

Regulation of brain acetylcholine concentration by muscarinic receptors.

The cholinergic agonists oxotremorine, oxotremorine-1, oxotremorine-3, arecoline and BM 123 (N-[4-(2-chloroethylmethylamino)-2-butynyl]-2-pyrrolidone) were used to investigate the role of muscarinic receptors in the regulation of acetylcholine (Ach) concentration in the whole mouse brain. Intravenous oxotremorine, oxotremorine-1, oxotremorine-3 and arecoline dose-dependently decreased ex vivo binding of [3H]oxotremorine-M and correspondingly increased brain Ach concentration. The correlation coefficient between the ED50's of these two parameters was 0.90. BM 123 induced percentage of reduction in muscarinic receptors correlated with percentage of decrease in response of oxotremorine, for increasing brain Ach concentration. These results indicate that the muscarinic receptor system involved in the regulation of brain Ach levels may lack spare receptors.

Acetylcholine↗
PubMedDate not supplied

Pyroglutamic acid improves learning and memory capacities in old rats.

The effects of the arginine salt of pyroglutamic acid (2-oxo-pyrrolidone carboxylic acid, PCA) on learning and memory capacities of old rats were studied in a subchronic treatment schedule (i.p. injection of 0.1 and 1 g/kg/day for 15 days). The acquisition and extinction of active avoidance behaviour were studied in a pole-jumping test situation. The retention of passive avoidance response was examined in a step-through passive avoidance task. PCA facilitated the rate of acquisition of pole-jumping response, and inhibited the extinction of the response. The dose of 1 g/kg was more potent than 0.1 g/kg in this respect. Also in the passive avoidance task, the treatment with PCA was followed by an improvement of avoidance retention. These results indicate that PCA is a behaviourally active compound in that it improves learning and memory capacities in old rat.

Aging↗
PubMedDate not supplied

[Effect of the degree of modification of trypsin amino groups with polymers on the enzymatic and conformation properties of the protein].

Trypsin was modified by introducing fragments containing an azo-bond into its molecule by the reaction of free amino groups of the enzyme with an azide of 2,2'-azobisisobutryic acid. Subsequently free-radical polymerization of N-vinyl pyrrolidone was carried out with the high molecular weight initiator obtained. The degree of modification of amino groups in trypsin was n = 6 divided by 12, which distinguishes this type of modification from that earlier proposed by the authors. In that case dichlorohydrate of dimethylimidate of 2,2'-azobisisobutyric acid was used for introducing azo-bonds into the molecule of the protein, n being equal to 2-3. It is shown that under the conditions of autolytic degradation both high molecular weight initiator based on trypsin and the trypsin-PVP (poly-N-vinyl pyrrolydone) covalent conjugates exhibit higher stability than initial trypsin. The method of circular dichroism was used for comparison of conformational properties of the modified trypsin forms. An increase of the rate of thermal inactivation was found to result from conformational changes occurring on modification of the enzyme.

Amines↗
PubMed1987

Effects of an alkylating derivative of oxotremorine (BM 123A) on heart rate, muscarinic receptors and adenylate cyclase activity in the rabbit myocardium.

The effects of the aziridinium ion (BM 123A) of a 2-chloroethylamine derivative of oxotremorine, N-[4-(2-chloroethylmethylamino)-2-butynyl]-2-pyrrolidone (BM 123), on heart rate, muscarinic receptor binding properties and adenylate cyclase activity were investigated in the rabbit myocardium. BM 123A was a potent inhibitor of heart rate in spontaneously beating rabbit hearts. Perfusion of hearts with BM 123A for 30 min caused a lack of sensitivity of the heart to the muscarinic agonist oxotremorine-M and an 80% alkylation of muscarinic receptors as measured by the reduction in the binding capacity of N-[3H]methylscopolamine. Alkylation of muscarinic receptors in the heart with BM 123A had no significant effect on adenylate cyclase activity by itself but caused a functional blockade of muscarinic receptor-mediated inhibition of adenylate cyclase activity. The reversible binding characteristics of both BM 123 and BM 123A were investigated in competitive binding experiments with N-[3H]methylscopolamine at 0 degree C, conditions under which little or no receptor alkylation occurs. The concentration of BM 123A required for half-maximal receptor occupancy was similar to that of oxotremorine-M whereas the parent mustard (BM 123) was 200-fold less potent. GTP (10 microM) had no significant effect on the binding of N-methylscopolamine but caused a 16-fold increase in the concentration of BM 123A required for half-maximal receptor occupancy.

Adenylyl Cyclases↗
PubMedDate not supplied

Square-wave voltammetric determination of acetaldehyde in povidone.

A rapid, precise, and accurate method is described for the determination of acetaldehyde in povidone (polyvinyl pyrrolidone). The sample is dissolved in a basic aqueous electrolyte and analyzed using square-wave voltammetry. The proposed method allows for direct measurement of acetaldehyde under gentle conditions, thus avoiding loss of analyte due to volatility of acetaldehyde. The method is specific for acetaldehyde in the presence of other aldehydes and povidone process impurities.

Acetaldehyde↗
PubMed1986

The effect of skin cleansing agents on ethanol results measured with the Du Pont automatic clinical analyzer.

The effect of various prepackaged skin cleansers on the results of serum ethanol analyses performed with the Du Pont automatic clinical analyzer has not been previously reported. When added directly to serum in concentrations of either 0.625 or 1.56% (v/v), neither polyvinyl-pyrrolidone iodine nor benzalkonium chloride affected the ethanol results. The cross-reactivity of isopropanol with the automatic clinical analyzer ethanol procedure was 3.9%. The greatest interference in the measured ethanol concentration was from the addition of green soap tincture, which contained 30% ethanol. The effect of improper phlebotomy technique on ethanol measurements was also investigated by performing venipunctures through a pool of 100% ethanol on the skin. No ethanol was detected in these samples unless an ethanol-soaked sponge was pressed over the venipuncture site while the needle was withdrawn from the skin. When correct phlebotomy technique is used, skin cleansing agents should not affect the results of ethanol measurements determined with the Du Pont automatic clinical analyzer.

Blood Specimen Collection↗
PubMed1986

Cholecystokinin--gene structure, and molecular forms in tissue and blood.

The gene structure of human cholecystokinin (CCK) is known and the cDNA structures are known for pig and rat. However, the molecular forms of CCK produced, stored and released from neural or endocrine cells cannot be predicted from the known structures of preprocholecystokinin derived from cDNA. It is well recognized that gastrin and CCK share carboxyl-terminal homology and similar processing to form the biologic active peptides. Comparisons of the structures of preprogastrin and preprocholecystokinin reveal a similar degree of homology in the midregion of the precursors (the structure of preprogastrin 55-59 and preprocholecystokinin 39-42 is His-Arg-Arg-Gln-Leu). Gastrin-34 (whose amino terminus corresponds to position 58 of preprogastrin) is formed by cyclization of glutamine to pyrrolidone carboxylic acid subsequent to cleavage at the double basis site. Identical posttranslational processing in this region would yield CCK-61. However, CCK-58 is the largest biologically active peptide so far isolated and chemically characterized. CCK can be found in high concentrations in gut and brain but the molecular forms differ in the two tissues. Thus, the most abundant forms in the intestine are CCK-58, followed by CCK-39, CCK-33, and CCK-8, whereas in the brain CCK-8 is the most abundant form, followed by CCK-58 and CCK-5. The brain contains in contrast to the intestine little or no CCK-39 and CCK-33. Therefore differences in posttranslational processing between gut and brain are assumed. The predominant small CCK forms in the brain act presumably as neurotransmitters. Large and small molecular forms are released from the endocrine cell of the gut and act as circulating hormones. Several problems have hindered the characterization and quantitation of CCK forms in tissue and blood. The large forms (CCK-58, CCK-39, CCK-33) are easily lost because they are more basic and bind to glass and plastic surfaces. In addition to recovery problems, CCK-58 can be readily degraded into smaller forms at neutral or basic pH in tissue extracts and in blood or plasma. When special care is taken to prevent these problems, we have shown that, in the dog, CCK-58 is not only the most abundant molecular form in the intestinal mucosa but also in the circulating blood. The physiology and pathophysiology of circulating CCK (regulation of pancreatic secretion, of the motility of the gallbladder and the bowel, and involvement in satiety mechanisms) has to be studied further.

Amino Acid Sequence↗
PubMed1985

The binding of a 2-chloroethylamine derivative of oxotremorine (BM 123) to muscarinic receptors in the rat cerebral cortex.

The interaction of a mustard analogue of oxotremorine, N-[4-(2-chloroethylmethylamino)-2-butynyl]-2-pyrrolidone (BM 123), with muscarinic receptors in the rat cerebral cortex was investigated using 3H-ligand-binding methods. When cortical homogenates were preincubated with BM 123 (1.0 mM), washed extensively, and then assayed for the binding of the specific muscarinic antagonist, [3H](-)-N-methylscopolamine, a decrease in binding capacity was noted without an accompanying change in affinity. The rate at which BM 123 alkylated muscarinic receptors was sensitive to temperature, with little or no receptor alkylation occurring at 0 degree. Thus, it was possible to estimate the affinity of BM 123 and its transformation products for muscarinic receptors by measuring their ability to competitively inhibit 3H-ligand binding to cortical homogenates at 0 degree. When measured by competitive inhibition of [3H]oxotremorine-M and [3H](-)-N-methylscopolamine binding, the concentrations of the aziridinium ion of BM 123 required to displace 50% of specific 3H-ligand binding were 3.5 nM and 4.5 microM, respectively. In contrast, the parent 2-chloroethylamine and its alcoholic hydrolysis product were much less active. The kinetics of the alkylation of muscarinic receptors by BM 123 were consistent with a model in which the aziridinium ion rapidly forms reversible complexes with superhigh high and low affinity sites which slowly convert to covalent complexes. The rate of alkylation of the superhigh affinity site was slowest whereas the converse was true for the low affinity site. It was possible to alkylate the high and low affinity sites selectively with BM 123 by taking advantage of kinetic differences in the rates of alkylation of these two sites. Atropine, oxotremorine, and oxotremorine-M antagonized the rate of alkylation of muscarinic receptors in a manner that was consistent with competitive inhibition.

Alkylation↗
PubMed1985

[Rehabilitation of patients with laryngeal cancer after fronto-lateral resections with endoprosthesis].

A newly-developed polymer endoprosthesis was used at the second stage of combined treatment of 20 patients with stage II--III laryngeal cancer to prevent persistent stenosis following resection of the larynx and to assure an earlier rehabilitation. Endoprosthesis was installed after fronto-lateral resection in all cases. The endoprosthesis was made from biologically-compatible materials on a preservative and regenerator agent-impregnated polyvinyl-pyrrolidone base. After being located in laryngeal lumen for 30--45 days, the prosthesis was removed endolaryngeally under out-patient hospital conditions and the cannula was taken out 6--10 days later. Within the following 12 months and longer, both laryngeal lumen and respiration were normal.

Adult↗
PubMed1985

[Formation of cells secreting antigen-dependent nonspecific immunoglobulins during immunization of mice with 2 T-independent antigens].

Immunization of BALB/c and C3H/A mice with T-independent antigens (Vi-antigen of Salmonella typhi and polyvinyl pyrrolidone PVP350) induces the appearance of both antibody-forming cells (AFC) and a sharp increase in the number of cells forming nonspecific immunoglobulins (nIFC). This effect is not related to mitogenic properties of the antigens. The number of nIFC formed after simultaneous injection of both T-independent antigens does not differ from that of nIFC formed during immunization with each of these antigens alone. Thus, there was no summation of nIFC number after injection of two T-dependent or one T-dependent and one T-independent antigens. The mechanisms of nIFC formation under the influence of T-dependent and T-independent antigens are discussed.

Animals↗
PubMed1979

[Interactions between macromolecular adjuvants and drugs. Part 16: Effects of human serum albumin and Mg2+ on oxytetracycline-polyvinylpyrrolidone interactions (author's transl)].

Equilibrium dialyses and fluorescent spectroscopic measurements demonstrated that human serum albumin (HSA) affects the oxytetracycline (OTC)--polyvinyl-pyrrolidone K 90 (PVP) interactions. The preferential binding of OTC with HSA, as compared to PVP, was evidenced by means of a three-compartment model. The binding values increased with the increase of the portion of PVP in the PVP-HSA mixture. Superadditive OTC bindings occurred at a ratio of 1:1 (by weight). The addition of Mg2+ to PVP-containing solutions, at a molar ratio of 1:1, also produced an increase of the interactions of this antibiotic with PVP, whereby maximal OTC-PVP bindings of 50--60% were reached.

Dialysis↗
PubMed1979

The complete primary structure of a proline-rich phosphoprotein from human saliva.

The complete amino acid sequence of a calcium-binding "proline-rich phosphoprotein," named Protein A, from human saliva was determined by automated and manual Edman degradation of peptides obtained by enzymatic and chemical cleavage of the intact protein. The NH2-terminal pyrrolidone carboxylic acid was identified by means of NMR. The protein consists of 106 amino acids, including 24 residues of proline. The NH2-terminal 32 residues contain 13 of the 15 negatively charged residues including 2 phosphoserines, but only 1 proline. In spite of a high concentration of proline in the COOH-terminal part of the molecule, the longest oligoproline sequence is tetraproline. The protein contains a number of repeated sequences and there are also several sequences of 3 or 4 residues identical with known sequences of collagen, but the characteristic occurrence of glycine in every third position in collagen is not found in salivary Protein A.

Amino Acid Sequence↗