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At least 1,747 records · Page 97Linked to original sources
PubMed2001

Enhancer aided in vitro permeation of atenolol and prazosin hydrochloride through mice skin.

Effect of penetration enhancers were studied on the permeation of antihypertensive drugs prazosin hydrochloride and atenolol through full thickness skin of swiss albino mice. Atenolol was delivered to skin from saturated alcoholic solution containing 5% of 1-decanol and alcohol alone, while prazosin hydrochloride was saturated in dimethyl formamide(DMF, 5% v/v in water) and dimethyl sulfoxide(DMSO, 5% v/v in water). Atenolol permeation was augmented significantly in decanolic solution and also in pure alcohol. In case of prazosin hydrochloride, significant enhancement of permeation was shown by DMSO but not by DMF.

Administration, Cutaneous↗
PubMed1975

[Inhibition of carbonic anhydrase by xipamide (4-chloro-sulfamoyl-2',6'-salicyloxylidide) in the modified Philpot test].

The inhibition of carbonic anhydrase by xipamide (4-chloro-5-sulfamoyl-2',6'-salicyloxylidide, Aquaphor), a poorly watersoluble saluretic agent, is determined with the Philpot method in the presence of 5 per cent N,N-dimethyl-formamide. The addition of the amide does not affect the enzyme. For xipamide 1.1 times 10-5 M is found as the 50 per cent inhibitory concentration.

Anilides↗
PubMed1975

[The chemistry of a chitin-protein from crayfish (Astacus fluviatilis) (author's transl)].

A chitin-protein complex is obtained from crayfish (Astacus fluviatilis) by gentle decalcification with acetic acid and EDTA. The complex is treated with lithium rhodanide, urea, anhydrous formic acid, pronase, papain, anhydrous formamide or 1N NaOH. The first three of these substances have little or no effect on the stability of the chitin-protein complex. The enzymes remove most of the protein, and the last two reagents remove all of it. The protein remaining bound to the polysaccharide after treatment of the chitin-protein complex with pronase or papain is relatively rich in glycine. Quantitative analysis yielded values for the acetyl, glucosaminyl and amino acid residues which reproduce the composition of the corresponding chitin-protein complex. In these calculations however, allowance must be made for the fact that glucosamine is partly destroyed by the acid by hydrolysis and interferes with the determination of basic amino acids. The results of the present work suggest that the chitin in crayfish is present in the form of a stable complex with protein, possibly held together by covalent binding of the protein to the chitin, with glycine as the connecting amino acid.

Amino Acids↗
PubMedDate not supplied

Azelastine's inhibition of histamine and tryptase release from human umbilical cord blood-derived cultured mast cells as well as rat skin mast cell-induced vascular permeability: comparison with olopatadine.

Mast cells are involved in early and late-phase reactions by releasing vasoactive molecules, proteases, and cytokines. Azelastine and olopatadine are histamine 1 receptor (H-1R) antagonists with antiallergic effects present in the ophthalmic solutions Optivar and Patanol, respectively. Because it is difficult to obtain animal or human conjunctival tissue, we first investigated the effect of these compounds on histamine and tryptase release from cultured human mast cells (CHMCs) grown out of human umbilical cord blood-derived CD34+ cells. Sensitized CHMCs were pretreated with various concentrations of azelastine or olopatadine for 5 minutes. Then, CHMCs were challenged with anti-immunoglobulin E (IgE) and the released mediators were quantitated. The greatest inhibition of mediator release was seen when CHMCs were pretreated with 24 microM of azelastine or 133 microM of olopatadine (2% dilution of azelastine or 5% olopatadine original ophthalmic solutions, respectively). We then studied the drug concentrations that gave optimal results on skin vasodilation induced by the mast cell secretagogue compound 48/80. An intradermal injection of 48/80 in rats, to which Evan's blue had been administered via the tail vein, induced substantial dye extravasation. Pretreatment of the injection site for 5 minutes with either 24 microM of azelastine or 133 microM of olopatadine completely prevented extravasation; this effect was quantitated also by fluorometric assessment of Evan's blue extracted in formamide. Evaluation of skin mast cells from injected sites showed that mast cell degranulation was inhibited greatly. These results indicate that on an equimolar basis, azelastine was a more potent inhibitor than olopatadine of both CHMC and rat skin mast cells activation.

Animals↗
PubMedDate not supplied

Determination of water (moisture) and dry matter in animal feed, grain, and forage (plant tissue) by Karl Fischer titration: collaborative study.

A Karl Fischer method for determining water (dry matter) in animal feed and forages was collaboratively studied. Water was extracted from animal feed or forage material into methanol-formamide (1 + 1) directly in the Karl Fischer titration vessel by high-speed homogenization. The water was titrated at 50 degrees C with one-component Karl Fischer reagent based on imidazole. Ten blind samples were sent to 9 collaborators in the United States, Canada, and Germany. The within-laboratory relative standard deviation (repeatability) ranged from 1.14 to 6.99% for water or from 0.09 to 0.56% for dry matter. Among-laboratory (including within-) relative standard deviation (reproducibility) ranged from 5.35 to 10.73%, or from 0.44 to 0.77% for dry matter. The authors recommend that the method be adopted as Official First Action by AOAC INTERNATIONAL. A comparable alternative extraction procedure using boiling methanol is also recommended for Official First Action.

Animal Feed↗
PubMed2002

Cytokine mRNA expression in experimental porcine pneumonia.

A porcine Pasteurella multocida (P. m.) infection model was established to study the spatial distribution of cytokine mRNA-expressing cells in lung tissue during acute pneumonia. The mRNA detection was performed by non-radioactive, formamide-free in situ hybridization (ISH) using oligonucleotides against the porcine interleukins (IL): IL-1 beta, IL-2, IL-4, IL-6, IL-8, TNF alpha and TGF beta. Cytokine mRNA-expressing macrophages were demonstrated by a double staining procedure combining immunohistochemistry (IH) using the primary antibody 2G6 with IL-1 beta, IL-6 and TGF beta ISH. With the exception of some stained TNF alpha-expressing cells, no IL mRNA was detectable in the lung of unaffected animals. The experimental P. m. pneumonia was characterized by a predominant, exudative and an additional proliferative interstitial component as well as abscess formation in the lung. Many cells of the region between the abscess membrane and the affected lung area showed high IL-6, IL-1 beta, IL-4 as well as TGF beta and few cells low IL-8 mRNA expression with characteristic distribution patterns. The ISH/IH double staining procedure revealed that at least some of the IL-6 or TGF beta-producing cells belonged to the 2G6-positive macrophages.

Animals↗
PubMedDate not supplied

Polymerization of lanthanide acrylonitrile complexes.

The molecular complexes of some lanthanides scandium (Sc3+), yttrium (Y3+), lanthanum (La3+), gadolinium (Gd3+), cerium (Ce3+) and ytterbium (Yb3) have been studies in dimethyl formamide (DMF) spectrophtometrically equilibrium constants (K), molar extintion coefficient (epsilon), energy of transition (E) and free energy (delta G*) were calculated. The polymerization of acrylonitrile has been studied and investigated in the presence of Sc3+, Y3+, La3+, Gd3+, Ce3+, and Yb3+ ions. The IR spectra of the formed AN-M (III) Br3 polymer complexes show the absence of the C identical to N band and the presence of two new bands corresponding to NH2 and OH groups. Magnetic moment values and the thermal stabilities of homopolymer and the polymer complexes were studied by means of thermogravimetric analysis and the activation energies for degradation were calculated.

Acrylonitrile↗
PubMed1975

[Viral genome integration with nuclear DNA in chronic viral infection].

A possibility of the integration of tick-borne encephalitis virus RNA in the host cell genome is studied under the condition of long-term chronic infection of HEp-2 cells. Molecular hybridization of viral RNA, labelled with 3H-uridine, and of DNA from intact and chronically infected cells was performed in 50% formamide with 0,4 M NaCl with subsequent investigation of the hybridization product by means of equilibrium centrifugation in CsSO4. 0,3 and 0,5 mg of DNA were used in hybridization experiments. It is shown that RNA obviously forms hybrids with DNA from chronically infected cells, whose density varied from 1,55 to 1,46 g/ml, depending on the proportion of RNA and DNA in the hybrids. When the amount of DNA increased, the number of DNA-RNA hybrids increased as well. It is concluded that in nuclear DNA of cells chronically infected with tick-borne encephalitis virus, there are DNA sites, homologous to viral RNA, which are absent in intact cells.

Cell Line↗
PubMed1975

Differential expression of alpha- and beta-globin genes during differentiation of cultured erythroleukemic cells.

Murine erythroleukemic cells induced to differentiate in vitro with dimethylsulfoxide provide a model for events involved in the regulated expression of the globin genes. Here we examine alpha- and beta-globin gene expression in such cells which contain no detectable globin RNA prior to induction. To quantitate alpha- and beta-globin RNAs in cellular RNA samples by molecular hybridization techniques, highly radioactive complementary DNAs were synthesized using mouse alpha- and beta-globin RNAs purified by formamide gel electrophoresis. Maximally induced erythroleukemic cells and mouse reticulocytes contain nearly equal relative amounts of alpha- and beta-globin RNA. During the period in which globin RNA accumulates in differentiating erythroleukemic cells, however, alpha- and beta-globin RNAs are not present in equivalent amounts. alphaRNA is present in substantial excess (alpha/beta ratio 3.7) early in induction, and the alpha/beta RNA ratio progressively approaches 1 as differentiation proceeds further. These observations directly suggest that the alpha- and beta-globin genes are differentially expressed during cellular differentiation and raise questions as to how relative expression of globin genes is controlled during normal development.

Animals↗
PubMedDate not supplied

Potentiometric and thermodynamic studies of 5-(p-aminophenylazo)-8-hydroxyquinoline and its metal complexes.

Proton-ligand dissociation constant of 5-(p-aminophenylazo)-8-hydroxyquinoline (HL) and metal-ligand stability constants of their complexes with bivalent (Mn2+, Co2+, Ni2+ and Cu2+) metal ions have been determined potentiometrically in 0.1 M KCl and 30% (v/v) dimethyl formamide (DMF)-water mixture. The order of the stability constants of the formed complexes was found to be Mn2+ < Co2+ < Ni2+ < Cu2+. The effect of temperature was studied and the corresponding thermodynamic parameters (delta G, delta H and delta S) were derived and discussed. The dissociation process is nonspontaneous, endothermic and entropically unfavorable. The formation of the metal complexes has been found to be spontaneous, endothermic and entropically favorable.

Algorithms↗
PubMed1976

Synthesis of human placental lactogen messenger RNA as a function of gestation.

It was shown previously that 4 to 5 times more human placental lactogen (hPL) was synthesized in cell-free extracts from term placentae than in comparable extracts prepared from first trimester tissue. In an attempt to define what accounts for this differential rate of synthesis RNA was prepared from first trimester and term placentae. Following purification through an oligo(dT)-cellulose column, these RNA preparations were tested for their ability to direct the synthesis of the hPL precursor in the wheat germ cell-free system. With similar amounts of first trimester and term mRNA, the overall efficiency as defined by the stimulation of total amino acid incorporation was comparable. However, there was approximately 4 times more hPL synthesized in the presence of term RNA. This was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tryptic fingerprinting. The peak of the hPL precursor messenger activity sedimented at 12 to 13 S on sucrose gradient. Analysis of the RNA by formamide-polyacrylamide gel electrophoresis further supported this value. The data indicate that the increased synthesis of hPL at term reflects greater levels of hPL mRNA in term tissue than in first trimester tissue. The data also show that the overall in vivo levels of hPL can be correlated not only with the increase in placental syncytial mass during pregnancy but also in the greater proportion of hPL synthesized per g of tissue. The latter results from the continual differentiation of the placenta occurring throughout gestation.

Female↗
PubMed2000

[Capillary gas chromatographic determination of residual benzene, toluene and DMF in acrylic fabrics].

A simple method for the analysis of residual benzene, toluene and N,N-dimethyl formamide (DMF) in acrylic fabrics by wide-bore capillary gas chromatography is presented. The sample was extracted by carbon disulfide (CS2) for an hour. The results showed that this is a rapid and sensitive method with less interferences and fairly good precision. The detection limits were 0.1, 0.1 and 2.0 ng for benzene, toluene and DMF respectively. The recoveries were 93.3%-101.8% and coefficients of variation were 2.0%-3.4%.

Benzene↗
PubMed2001

[Separation of catechins and caffeine in tea polyphenol by isocratic elution high performance liquid chromatography].

The catechins, particularly in green tea, have been found to possess anti-mutagenic and anti-tumorigenic properties. As each catechin possesses distinct properties, a simple and rapid method that could be used for analysis of individual catechins in a complex mixture would be necessary. A relatively simple and rapid method for simultaneous separation of five catechins and caffeine in tea polyphenol by isocratic elution high performance liquid chromatography has been developed. The analysis could be finished within 30 min. They were measured using Resolve C18 column (at 43 degrees C) and UV detector (at 280 nm), water-85% phosphoric acid aqueous solution-acetonitrile-dimethyl formamide(DMF) (859:1:120:20, V/V) as mobile phase. There was a good linear relationship between the content of component and its peak area for catechins and caffeine, with the correlation coefficients of 0.9992-0.9999. The average recoveries (n = 5) were 83.33%-104.42%, and the relative standard deviations (n = 6) were 0.74%-1.43%. The effect of concentration of DMF in mobile phase was studied.

Caffeine↗
PubMed1976

Purification and properties of biologically active rainbow trout testis protamine mRNA.

At least two classes of protamine mRNA are present in both trout testis polysomal RNA and RNA from the postribosomal supernatant fraction of trout testis hormogenate both of which direct the synthesis of protamine in a Krebs II ascites S-30. One contains poly(A) tracts and the other is devoid of poly(A). Sucrose gradient analyses showed that the poly(A) containing protamine mRNA (poly(A) (+)) sedimented IN THE 6 S region with a shoulder in the 4 S region while the protamine mRNA devoid of poly(A) (poly(A) (-)) appeared to sediment at about 4 S and could not be resolved from tRNA. Analysis of the poly(A) (+) protamine mRNA by boundary sedimentation in an analytical ultracentrifuge showed a sedimentation coefficient of 5.7 S, a value which gives rise to an estimate of 165 to 170 nucleotides per molecule. The poly(A) (+) protamine mRNA migrated as a single species in formamide-containing polyacrylamide gels and its mobility in relation to markers of tRNA (4 S) and 5 S RNA was consistent with its sedimentation velocity of 6 S. The RNA present in the major band on an aqueous polyacrylamide gel was extracted and shown to code for protamine in a wheat germ cell-free system.

Animals↗
PubMedDate not supplied

[Sedimentation properties of virion RNA of Newcastle disease virus after annealing under different conditions].

After annealing at high temperatures 50S RNA of Newcastle disease virus was partially degraded. The resulting fragments had the sedimentation coefficient of 23--32S. Solution of dimethylsulfoxide and formamide were used to decrease the temperature of annealing. However, annealing with denaturating agents caused agglomeration of 50S RNA molecules. This phenomenon is discussed.

Centrifugation, Density Gradient↗
PubMed1977

Life and the outer planets. II. Enzyme activity in ammonia-water systems and other exotic media at various temperatures.

Enzyme activities are customarily measured in aqueous solutions. Activity and thermodynamic parameters are based upon behavior in these solutions although they in no way represent the highly structured internal surface system of the cell. Actual environmental limits for enzyme action may be greater than generally assumed. Peroxidase, catalase, urease and amylase retain activity in drastically modified aqueous and nonaqueous media, including aprotic solvents. Examples include formic acid, methanol, formamide, nitromethane, 10 M LiCl and 15 M aqueous ammonia. Temperatures as low as 225-233 degrees K permit activity in some media. Ammonia-rich environments are compatible with some forms of terrestrial life. Enzyme activity in these exotic media and conditions is relevant to chemical evolution on Jupiter and similar planetary systems.

Ammonia↗
PubMed1975

Endotoxin-like properties of the peptidoglycan.

Peptidoglycan is responsible for the endotoxin-like properties of the streptococcus cell wall. The pyrogenic response of rabbit to group A streptococcus peptidoglycan prepared by hot formamide or TCA is dose-dependent and is increased if the material is ultrasonically solubilized. The pyrogenicity can be eliminated by the antiserum to the peptidoglycan or by the degradation of the material by lysozyme. Peptidoglycans prepared from cell walls of group B and L streptococci, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pneumoniae produce fever effects comparable to the response after group A streptococcus peptidoglycan. Spirillum serpens and Escherichia coli contain in addition to endotoxin the peptidoglycan which is also pyrogenic. Repeated injections of bacterial peptidoglycan to rabbit result in tolerance to the fever effect. Cross-tolerance was recorded only exceptionally. Rabbits tolerant to endotoxin respond with a lower fever to S. aureus and group A streptococcus peptidoglycans. Intravenous administration of peptidoglycan to rabbit causes extensive alterations in the heart characterized by various stages of the degenerative and necrotic process. Local Shwartzman reaction can be elicited in rabbit by peptidoglycan used either as a preparative or as a provocative dose in combination with endotoxin, or it can be used for both doses. The results obtained with peptidoglycans prepared from various bacteria are fully comparable. Non-specific resistance of mice to infection induced by streptococcus cell walls was found to be dependent on the peptidoglycan activity; cell wall proteins and polysaccharide are inactive. These properties of peptidoglycan resemble those known from endotoxin studies. The data presented suggest the role of peptidoglycan in pathological reactions resulting from host-parasite interaction.

Animals↗
PubMed1975

The thrombocytolytic activity of bacterial peptidoglycans.

The peptidoglycan of group A Streptococcus prepared by hot formamide or TCA extraction has an expressive ability to lyse rabbit blood platelets in vitro. Initial changes in the ultrastructure of platelets can be observed after 10 minutes incubation of rabbit platelets with 0.1 mug of Streptococcus peptidoglycan per ml. The submicroscopic alterations are characterized by changes of the shape and damage of the limiting membrane of the platelets. Larger amounts of peptidoglycan (10 mug/ml and more) cause total destruction of platelets; only remainders of the limiting membrane and free granulomers can be seen. Peptidoglycans of Streptococcus pneumoniae and Staphylococcus aureus exhibit a comparable effect on rabbit platelets. There are substantial differences in the sensitivity of blood platelets of different animal species to the streptococcal peptidoglycan. Rat platelets exhibit a similar thrombocytolytic effect after the Streptococcus peptidoglycan treatment as rabbit ones; however, the development of comparable changes in their submicroscopic structure needs a dose of peptidoglycan 10(2)-10(3) times higher. Platelets of guinea-pig, dog, cat, calf and human appear to be quite resistant under analogous conditions to as such a high dose of Streptococcus peptidoglycan as 500 mug/ml.

Animals↗