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At least 163 records · Page 9Linked to original sources
PubMed1984

Hepatic microvascular regulatory mechanisms. IV. Effect of lodoxamide tromethamine and arterenol-HCl on vascular responses evoked by compound 48/80.

Changes in the hepatic microvasculature and systemic arterial blood pressure were measured in anesthetized Sprague-Dawley rats receiving an i.v. infusion or topical application of compound 48/80, lodoxamide, or arterenol. Histochemical determination of the number of Falck-Hillarp positive (serotonin containing) mast cells also was performed on sections of liver at the light microscopic level. The infusion of arterenol (0.1 mg/kg) or Ringer's solution (control) provoked a vasopressor response within 25 sec in rats rendered hypotensive 5 min previously with compound 48/80. The duration of this response was brief with arterial pressure returning to the pre-injection (hypotensive) state within 3 min following arterenol or Ringer's administration. The injection of lodoxamide (a purported inhibitor of histamine release) inhibited compound 48/80-induced hypotension at all doses except 1 mg/kg. In vivo microscopy revealed that topical administration (0.1 microgram) significantly antagonized the microvascular responses elicited by compound 48/80. However, higher doses of lodoxamide (1.0-10 micrograms) when applied topically were found to be vasoactive. Given these results and the histochemical demonstration of an inhibition of compound 48/80-induced release of serotonin, it is suggested that: lodoxamide antagonizes the action of compound 48/80 by blocking the release of mast cell constituents, and neither compound 48/80 nor the released constituents appear to modify vascular responsiveness to arterenol or hypervolemia following the initiation of hypotension.

Amino Acids↗
PubMed2003

Vibrational characterization of the peptide bond.

This article describes the complete vibrational analysis of N,N'-dimethyloxamide, CH3HNCOCONHCH3, on basis of the infrared and Raman spectra of four isotopes (H, D, CH3, CD3). Force field calculations on the monomers and multimers (n = 5) combined with solid state spectra in the -196 to +100 degrees C temperature range have been used to obtain a better understanding of the influence of hydrogen bonding on the typical amide fundamentals. The cooperative effect in de series monomer --> multimers --> solid state at decreasing temperatures has been demonstrated. Nine typical so-called 'amide bands' have been further characterized and special attention has been given to the Amide IV mode. The influence of the CH and CD vibrations on the amide fundamentals, has been studied by comparison with the calculated and experimental fundamentals and P.E.D. values of the CH3 and CD3 isotopes. The most important amide bands have further been assigned in X-CONHCH3 molecules where X = methyl, amide, thioamide, ester, salt, cyanide and acid functional groups.

Acetamides↗
PubMed1999

Oxalate-induced and cell-cycle-dependent expression of nuclear pore complex oxalate binding protein gp210.

The effect of oxalate, a constituent of renal stone, on the expression of nuclear pore complex oxalate binding protein (gp210) in Vero monkey kidney cells was examined. The expression of this protein was found to increase more in mitotic phase than in S phase, suggesting cell cycle dependency. Exposure of cells to oxalate-containing growth medium resulted in a relative increase in nuclear pore complex oxalate binding protein in each stage of cell cycle. The concentration of this protein was found to increase six times in the telophase stage of the cells exposed to high concentrations of oxalate in the growth medium, though slight reduction in cell density was observed. Structural analogues of oxalate did not show any stimulatory effect on expression of this oxalate binding protein. Hence, the expression of the nuclear pore complex oxalate binding protein gp210 was specific to oxalate and is cell cycle dependent.

Animals↗
PubMed1975

Isoelectric-focusing behavior of acid hydrolases in rat kidney lysosomes. Effects of the pH gradient, autolysis and neuraminidase.

Isoelectric focusing was used to study the multiple forms of acid phosphatase, arylsulfatase, beta-glucuronidase and beta-N-acetylhexosaminidase in lysosomes isolated from rat kidney. The isoelectric points of the main protein and hydrolase peaks were 1-1.5 units lower when electrofocusing was done in a pH 3-10 gradient than in a pH 10-3 gradient, apparently because the lysosomal constituents aggregated strongly at their isoelectric points and tended to settle somewhat in the gradient due to gravity. In the extended pH gradient the acidic form of each hydrolase occurred as asingle, relatively discrete peak. However, when pooled acidic fractions were refocused in a restricted pH gradient (pH 6-3 or 3-5) multiple acidic enzyme and protein components were resolved with isoelectric points between 2.7 and 5.1. When autolysis was minimized by extracting lysosomal fractions at alkaline pH (0.2% Triton X-100, 0.1%p-nitrophenyloxamic acid, 0.1 M glycine buffer, pH9) and including 0.1%p-NITROPHENYLOXAMIC ACID, AN INHIBITOR OF LYSOSOMAL NEURAMINIDASE AND CATHEPSIN D, in the pH gradient, arylsulfatase, beta-glucuronidase and beta-N-acetylhexosaminidase occurred in two forms, an acidic form with an isoelectric point of about 4.4, and a basic form with an isoelectric point close to 6.2, 6.7 and 8.0, respectively. Acid phosphatase occurred in three forms with isoelectric points of 4.1, 5.6 and 7.4. When some autolytic digestion was permitted by extracting lysosomal fractions in an acidic medium (0.2% Triton X-100, 0.1 M sodium acetate buffer, pH 5.2) AT 0-4DEGREES C and omitting p-nitrophenyloxamic acid from the gradient, the acidic form of beta-glucuronidase and the intermediate form of acid phosphatase were lost, the isoelectric points of the acidic forms of acid phosphatase, arylsulfatase and beta-N-acetylhexosaminidase were increased 0.6-1.2 units, and the isoelectric point of the basic forms of acid phosphatase, arylsulfatase and beta-glucuronidase was increased 0.5 unit. When lysosomal extracts were incubated with bacterial neuraminidase before electrofocusing, the acidic forms of acid phosphatase, arylsulfatase and beta-glucuronidase were largely lost, the isoelectric point of the acidic form of beta-N-acetylhexosaminidase was increased from 4.5 to 6.4, and the isoelectric points of the basic forms of all four hydrolases were increased 0.5-1.5 units. Autoincubation of lysosomal extracts in vitro at pH 5.2 PRODUCED SIMILAR, THOUGH LESS MARKED, effects. cont'd

Acid Phosphatase↗
PubMed1990

Antiallergic and anti-inflammatory action of tioxamast in rats. I. Antiallergic activity in vivo and in vitro.

Tioxamast (F 1865) is an antiallergic drug that, administered systemically, reduces anaphylaxis in various models in rats. This action is due mainly to the inhibition of the synthesis and release of certain mediators. Orally or intraduodenally administered tioxamast inhibits IgE-dependent passive cutaneous anaphylaxis (ED50 = 0.8 mg/kg), IgE-dependent passive pulmonary anaphylaxis (ED50 = 0.5 mg/kg), and IgG-dependent passive cutaneous anaphylaxis (ED50 = 0.6 mg/kg). It has little or not effect on the increase of cutaneous capillary permeability induced by various mediators. In IgE-dependent passive peritoneal anaphylaxis in rats, tioxamast reduces the release of histamine (IC50 = 0.024 micrograms/ml) and of beta-glucuronidase (IC50 = 0.102 micrograms/ml). Also, histamine release is inhibited in IgG-dependent peritoneal anaphylaxis (IC50 = 0.103 micrograms/ml). The antiallergic compound has less effect on the release of histamine induced by the compound 48/80 in the peritoneal cavity of rats (IC50 = 1.67 micrograms/ml). Tioxamast inhibits the synthesis in vitro of leukotriene B4 (LTB4) by peritoneal neutrophils from rats stimulated by A23187 (IC50 = 8.88 micrograms/ml). At higher tioxamast concentrations, metabolites of the cyclo-oxygenase pathway are inhibited at concentrations of the same order of magnitude as those that inhibit Naja naja phospholipase A2 (IC50 = 144 micrograms/ml). Tioxamast also reduces the production of free radicals by leukocytes from the pleural cavity of rats which had phagocytosed opsonized zymosan (IC50 = 5.21 micrograms/ml).

Anaphylaxis↗
PubMed1977

[Hyperoxaluria in intestinal and liver diseases].

Excretion of oxalic acid in urine was measured in 28 healthy and 97 patients with gastrointestinal diseases. We found significantly higher values in the following groups: patients after resection of parts of the small intestine, patients with sprue and other diseases with malabsorption, patients with M. Crohn of the small intestine, colitis ulcerosa and granulomatosa, patients with chronical diseases of the pancreas gland and patients with cirrhosis of the liver. In 4 patients after resection of parts of the small intestine or pancreas urolithiasis could be verified. Reduction of fat and food without ballast reduced the excretion of oxalic acid in urine. Hyperoxaluria correlied significantly with the following parameters: excretion of fat in feces, exhalation of 14CO2 in the glykocholate breath test, resorption of vit. B12 and the length of resected small intestine. This form of hyperoxaluria is caused by hyperresorption of oxalic acid from food. The mechanism of this hyperresorption is not clarified yet, an important factor seems to be ill resorption of fat.

Amino Acids↗
PubMed1976

[The interaction of pyridine-adenine-dinucleotides containing a hydrazide group with swine muscle lactate dehydrogenase].

Hydrazide group of 4-substituted NAD analogues is shown to interact with functional groups of substrate-binding site in double complexes with pig muscle lactate dehydrogenase (isoenzyme M4). The lactic acid residue, which is structurally incorporated into NAD analogue, improves slightly the binding of dinucleotide, while 2,2,6,6-tetramethylpiperidine-1-oxyl residue considerably decreases the firmless of binding. The comparison of the inhibitory ability of oxamate, incotinic acid hydraxide and their spin-labelled derivatives indicates the restricted and stiff sizes of a substrate-binding site.

Animals↗
PubMed1982

The effect of lodoxamide tromethamine on the immediate asthmatic response to allergen provocation.

The inhibition of immediate allergen-induced airflow obstruction by lodoxamide tromethamine (LT), a new drug with properties considered to be similar to those of sodium cromoglycate, was studied in twelve young asthmatic volunteers. Single aerosolized doses of 0 X 01 mg LT, 0 X 1 mg LT or placebo were administered by inhalation 15 min prior to allergen provocation at weekly intervals, in a double-blind random order study. Following inhalation of both doses of LT a significantly greater amount of allergen had to be administered to cause a 20% fall in the forced expiratory volume in one second (FEV1) from control levels than was the case following placebo pre-treatment (P less than 0 X 001). After single-dose inhalation of LT only minor unwanted effects were recorded; in particular a transient feeling of heat in the upper respiratory tract after inhalation of the higher dose of drug.

Administration, Intranasal↗
PubMed1984

Effect of lodoxamide on the secretory response induced by Escherichia coli and Vibrio cholerae enterotoxins in infant mice.

The effect of lodoxamide tromethamine, a calcium antagonist, on intestinal fluid accumulation induced by Escherichia coli heat-stable (ST) and Vibrio cholerae (CT) enterotoxins in infant mice was investigated. The simultaneous administration of lodoxamide with ST or CT enterotoxin resulted in a significant (P less than 0.01) inhibition of the intestinal fluid response. A minimum concentration of 10(-7) or 10(-8)M lodoxamide caused an inhibition (P less than 0.01) of the ST- or CT-mediated fluid response, respectively. Treatment of infant mice with buffer or drug alone did not result in fluid accumulation. A significant inhibition of ST and CT enterotoxic activities was also observed when lodoxamide was administered 30 min before (P less than 0.02) or 30 min after (P less than 0.01) toxin challenge. These data suggest that calcium may be important in the ST- or CT-mediated induction of fluid accumulation. Further studies on the potential use of lodoxamide tromethamine in both the prophylaxis and treatment of diarrheal disease appear warranted.

Amino Acids↗
PubMed1986

The characterization of lodoxamide, a very active inhibitor of mediator release, in animal and human models of asthma.

A most active biologue of disodium cromoglycate (DSCG) available, lodoxamide tromethamine (LT), has been studied and characterized pharmacologically, in animal and human models of asthma. It has self-tachyphylaxis, but has oral activity (lodoxamide ethyl) in rats, primates, and man. In rats (LT) was 2,500 X more active than DSCG (ID50 = 0.001 mg/kg), in primates the drug was also active by several routes (inhalation 1 microgram/kg, IV 0.001 mg/kg, and oral 10 mg/kg). In isolated rat peritoneal mast cells, the compound displayed a biphasic dose response inhibition to histamine release initiated by (48/80, anti-IgE, and the calcium ionophore A23,187) with IC50 values of 0.1-50 microM. The consistent finding relating to its mode of action was its ability to inhibit 45calcium flux into the mast cell in response to antigen or A23,187. Clinical evaluations of lodoxamide tromethamine showed that at aerosol doses of 1.0 mg or less, it demonstrated significant inhibitory activity against antigen or exercise induced bronchospasm. However, in pilot evaluation studies in clinical asthma settings, the compound could not be shown to spare bronchodilator usage, relative to placebo, or be shown to be more effective than placebo treated patients based on other clinical endpoints. The reason for rat and primate models not being predictive for human long-term clinical asthma in the characterization of anti-release compounds is not known.

Amino Acids↗
PubMed1983

Inhalation challenge with specific grass pollen antigens in asthmatics and the effect of lodoxamide tromethamine.

Highly purified species-specific grass pollen antigens were used for inhalation bronchial challenge in 12 patients with atopic asthma. This was found to result in reproducible experimental asthma. Lodoxamide tromethamine was administered by inhalation in two different doses, 0.01 mg and 0.1 mg, to each patient, in double-blind, random, placebo-controlled manner, 15 minutes before pollen inhalation. It was found to have a significant protective action at both doses (p less than 0.05), but it produced troublesome side effects at the higher dose of 0.1 mg.

Adult↗
PubMed1978

Inhibition of allergic reactions by cromoglycate and by a new anti-allergy drug U-42,585E. I. Activity in rats.

A new inhibitor of IgE-mediated allergic reactions has been studied in rats. This new inhibitor is chemically different from cromoglycate and shows qualitative and quantitative advantages over it. It is 2,500 times more active in rats than disodium cromoglycate and shows oral activity. This new inhibitor possesses no bronchodilator or end-organ antagonism activity and does not raise intracellular cAMP levels but as cromoglycate acts by inhibition of mediator release. Multiple high (25 mg/kg) doses in rats lead to tachyphylaxis. This effect is reversed both by decreasing the first dose and increasing the time between doses. Over a 5- to 10-fold concentration range, this inhibitor in mast cells can be stimulatory or inhibitory to 45Ca++ flux into cells. This ability to inhibit ionophore-induced 45Ca++ flux correlates well with inhibition of histamine release.

Administration, Oral↗
PubMed1988

Kinetic measurement of the combined concentrations of acetoacetate and beta-hydroxybutyrate in serum.

This is an automated method for the kinetic measurement of the combined concentrations of acetoacetate and beta-hydroxybutyrate in a single channel of the "Multistat III" centrifugal analyzer. Acetoacetate is first reduced with high concentrations of NADH by catalysis with 3-hydroxybutyrate dehydrogenase (EC 1.1.1.30). This reaction mixture is diluted with excess NAD+. The endogenous beta-hydroxybutyrate and that resulting from acetoacetate are then measured kinetically. Comparing the combined concentration of acetoacetate and beta-hydroxybutyrate (y) with the sum of acetoacetate and beta-hydroxybutyrate measured as described by Hansen and Freier (Clin Chem 1978;24:475) (x) yielded the relationship: y = 0.99x - 0.57 (r = 0.93, n = 25). The run-to-run CVs for low (5 mmol/L) and high (15 mmol/L) acetoacetate controls were 12% and 6%, respectively. The method is useful for determining the concentration of ketone bodies in 2-microL samples of serum of patients with diabetic ketoacidosis. The sensitivity can be increased to determine ketone body concentration in nonketotic individuals by increasing sample volume to 10 microL.

3-Hydroxybutyric Acid↗
PubMed1982

The pharmacologic profile of wy-41,195, a new orally effective antiallergic agent.

[2-Cyano-3-(methylamino)phenylamino]oxoacetic acid, sodium salt (Wy-41,195) was found to be a potent oral inhibitor (viz., ED50, 0.3 mg/kg) of IgE-mediated release in the rat passive cutaneous anaphylaxis (PCA) model and was very effective by the aerosol and oral route in the rat passive lung anaphylaxis model. High doses (25-50 mg/kg p.o.) were effective when administered up to 180 min before antigen challenge in the rat PCA model. The compound had minimal phosphodiesterase activity and demonstrated no bronchodilator or antihistamine activity. In the dog, Wy-41,195 inhibited histamine-induced reflex bronchoconstriction but had little effect on Ascaris-induced bronchoconstriction. No significant ancillary pharmacology was observed for Wy-41,195 except for inhibition of gastric secretion in the rat. The compound is relatively nontoxic and possesses a very high therapeutic index (greater than 10 000). Activity in these animal systems indicates that Wy-41,195 may hold promise in the treatment of bronchial asthma and other allergic diseases in man.

Amino Acids↗
PubMed2006

Chemical hybridizing agents for chickpea (Cicer arietinum L.): leads from QSAR analysis of ethyl oxanilates and pyridones.

In the self-pollinated crops such as chickpea, induction of male sterility by deployment of chemical hybridizing agents (CHAs) facilitating "two-line" approach holds immense potential in heterosis breeding. A total of 40 test CHAs comprising 20 ethyl oxanilates and 20 pyridones were screened as potential CHAs on chickpea (variety BG 1088) at 500, 800, and 1000 ppm. Three test compounds mostly having either F (4)/Br (5)/CF(3) (19) at the para position of the aryl ring from a pool of 20 ethyl oxanilates were identified as the most potent CHAs causing >or=99% induction of pollen sterility and >90% total flower sterility at 1000-ppm test concentration. Among pyridone derivatives, N-(4-chlorophenyl)-5-carbethoxy-4,6-dimethyl, 1,2-dihydropyrid-2-one (26) was found to be the most active. Quantitative structure activity relationship (QSAR) analysis has revealed a direct involvement of Swain-Lupton field constant, F(p), with the target bioactivity which implied that field rather than resonance effect (R) had a positive effect on the activity. The real guiding principle for selectivity was found out to be the hydrophobic parameter pi value. The QSAR models indicated that increased steric bulk at the 4-position on the phenyl ring is associated with enhanced activity. The CHAs appeared to act by mimicking UDP-glucose, the key substrate in the synthesis of callose, or lead to an imbalance in acid-base equilibrium in pollen mother cells resulting in dissolution of callose wall by premature callase secretion.

Breeding↗