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PubMed1989

Hydrogen ion titration of 12 S rape seed protein and partial N-terminal sequence of one of it's subunits.

The high molecular weight 12 S protein from rape seed was isolated in a homogeneous form and characterized. Six subunits were isolated by PAGE in the presence of SDS and 0.2 M 2-mercaptoethanol. These subunits (s1 to s6) were found in the protein in the weight ratio of 1.32:1.2:1.15:1.0:1.21:1.11. The molecular weights and first two N-terminal amino acids of the isolated subunits were 64,800 and phenylalanine, alanine (s1), 50,650 and valine, tyrosine (s2), 42,500 and phenylalanine, leucine (s3), 28,800 and threonine, glutamic acid (s4), 19,100 and cystine, isoleucine (s5) and 15,600 and alanine, phenylalanine (s6). The number of side chain carboxyl, imidazole and epsilon-amino groups were calculated from the hydrogen ion titrations, which were in agreement with the amino acid assay. Besides, the N-terminal amino acid sequence upto 43 residues for one subunit (s6) is reported using Edman degradation.

Amino Acid Sequence↗
PubMed1989

Titration studies on the active sites of pig heart lipoamide dehydrogenase and yeast glutathione reductase as monitored by the charge transfer absorbance.

Macroscopic pKa values associated with the influence of pH on the visible spectrum of 2-electron reduced pig heart lipoamide dehydrogenase and yeast glutathione reductase have been determined by monitoring changes in the principal flavin band near 460 nm and the charge transfer band at 540 nm. The ionization of at least three active site amino acid side chains can influence the spectra over the range of pH studied: the two nascent thiols (interchange thiol and electron transfer thiol) and the histidine residue which acts as the base catalyst in lipoamide dehydrogenase and the acid catalyst in glutathione reductase thiol-disulfide interchange reactions. These systems are analogous to, but more complex than, those in glyceraldehyde-3-phosphate dehydrogenase and papain where a single thiol and a histidine residue in a relatively apolar milieu form a thiolate-imidazolium ion pair which is favored over the thiol-imidazole prototropic tautomer. In an effort to more nearly mimic the papain titrations, the macroscopic pKa values were determined on reduced glutathione reductase which had been monoalkylated with iodoacetamide under conditions known to favor the reaction of the interchange thiol by at least 10 to 1 (Arscott, L. D., Thorpe, C., and Williams, C. H., Jr. (1981) Biochemistry 20, 1513-1520). Like papain and glyceraldehyde-3-phosphate dehydrogenase, alkylated glutathione reductase showed two macroscopic pKa values, at pH 3.7 and pH 9.1, and by analogy, these were associated primarily with the thiol and the imidazole, respectively. Results with the native enzymes depended on the wavelength monitored. Glutathione reductase had pKa values at 4.8, 7.1, and 9.2 when monitored at 540 nm and 5.1 and 8.2 when monitored at 462 nm. Lipoamide dehydrogenase had pKa values at 4.4 and 8.7 when monitored at 529 nm and 3.9, 7.0, and 9.3 when monitored at 455 nm.

Animals↗
PubMed1989

Dose titration and confirmation tests for determination of cesticidal efficacy of epsiprantel in dogs.

Fifty-five dogs, naturally infected with Taenia sp or Dipylidium caninum or both, were assigned to the following treatment groups for dose titration studies with epsiprantel: nonmedicated control dogs (n = 14), medicated dogs given a dosage of 2.75 mg/kg of body weight (n = 15), medicated dogs given a dosage of 5.5 mg/kg (n = 16), and medicated dogs given a dosage of 8.25 mg/kg (n = 10). Medication was given orally in a tablet formulation. Feces were examined for cestodes passed and the gastrointestinal tract was examined at necropsy for retained cestodes. Efficacy of epsiprantel was 92.9% against Taenia and 44.8% against Dipylidium for a dosage of 2.75 mg/kg, 100% against Taenia and 99.8% against Dipylidium for a dosage of 5.5 mg/kg, and 94.6% against Taenia and 100% against Dipylidium for a dosage of 8.25 mg/kg. For dose confirmation, 36 dogs naturally infected with Taenia sp or D caninum or both were allotted to 2 treatment groups: nonmedicated control dogs (n = 16) and dogs medicated with epsiprantel at a dosage of 5.5 mg/kg (n = 20). Efficacy was 100% for both Taenia sp and D caninum.

Animals↗
PubMedDate not supplied

Efficacy of diclazuril against turkey coccidiosis in dose-titration studies.

Diclazuril, a new anticoccidial drug, was tested for its efficacy in turkeys against single Eimeria infections. Dose-titration studies indicated that diclazuril at dosages of 0.1, 0.5, 1, and 2 ppm was highly effective against the major pathogenic species-E. adenoeides, E. gallopavonis, and E. meleagrimitis-in terms of weight gain and suppression of lesions, abnormal droppings, and oocyst shedding.

Animals↗
PubMedDate not supplied

[Determination of metronidazole in vehicles used externally by titration in a nonaqueous medium].

The analytical procedure has been elaborated for determination of metronidazole contents in the formulated preparation for external application in the form of a cream. Ambiphilic and emulsion bases were used as a vehicle. Water is removed from the preparation by drying/1 hour at 105 degrees C/and the amount of dry metronidazole residue is determined by titration in nonaqueous media with, 0.01 mol/l of perchloric acid.

Chemistry, Pharmaceutical↗
PubMed1986

The titration of clostridial toxoids and antisera in cell culture.

The practicability of cell culture titration methods for antigens and antitoxins derived from Clostridium perfringens, Cl. septicum and Cl. novyi was investigated. Toxin neutralization could not be demonstrated with Cl. perfringens filtrates but assays for antitoxin based on the use of cultures of Vero cells were practicable for Cl. novyi and Cl. septicum. In the case of the latter, the precision and reproducibility of the test was sufficient for quality control purposes.

Animals↗
PubMed1988

Esmolol: a short-acting titratable beta-blocker in acute myocardial ischemia.

Esmolol (Brevibloc) is a potent, titratable, cardioselective beta-blocker with a short elimination half-life (t1/2 = 9.2 min) and no intrinsic sympathomimetic activity. It was designed for use in critically ill patients who would benefit from the short duration of beta-adrenergic blockade. Esmolol's short duration of action allows for rapid onset and control of hemodynamic effects. Its safety and efficacy has been demonstrated in patients with acute myocardial ischemia. This review provides a brief summary of the pharmacology of esmolol, as well as experimental and clinical evidence on the use of esmolol in acute myocardial ischemia.

Acute Disease↗
PubMed1987

The effects of N-allylnormetazocine on electric shock titration in squirrel monkeys.

The effects of the stereoisomers of the prototypic sigma agonist N-allylnormetazocine were evaluated in squirrel monkeys trained to respond on an electric shock titration schedule. The monkeys responded on a fixed-ratio schedule to decrease the level of shock delivered to their tails. The effects of the isomers were compared to the effects of phencyclidine and morphine administered alone and also in combination with a rate-suppressing dose of morphine. Morphine increased the level at which shock was maintained without decreasing rates of responding in the presence of shock. Both the (+)-isomer and PCP produced increases in the levels at which the monkeys maintained the shock, but only in some animals. The (-)-isomer of N-allylnormetazocine resulted in either decreases or no effect on the level at which the monkeys maintained the shock. The isomers were equipotent in decreasing response rates. When tested in combination with morphine, only the (-)-isomer antagonized the shock-level increasing effects of morphine. Thus, the isomers had similar effects on response rates but the (+)-isomer, like PCP, was more effective in increasing the level at which the monkeys maintained electric shock, while only the (-)-isomer was effective as a morphine antagonist. These results suggest analgesic-like effects for the (+)-isomer of N-allylnormetazocine and substantiate the opiate-antagonist properties of the (-)-isomer.

Animals↗
PubMed1978

Titration and circulation of cells mediating delayed type hypersensitivity in normal and cyclophosphamide treated mice during response to sheep red blood cells.

The delayed-type-hypersensitivity (DTH) reaction observed in mice primed i.v. with low doses of sheep red blood cells is not detectable after priming with large doses. Estimation of the number of DTH mediating cells (DTH-C) was performed by titration (D50 determination) using local adoptive transfer of these cells mixed with antigen into footpads of unprimed mice. In opposition to the absence of peripheral DTH-C, splenic DTH-C were more numberous after large doses than after low doses of antigen. The ability of cyclophosphamide to restore DTH responsiveness in mice primed with large doses appeared to be related to an increased cirulation of DTH-C. These cell circulated only in mice without any detectable B-cell response or in which this response was depressed. Thus a B-cell dependent splenic retention process of DTH-C is discussed as the origin of DTH unresponsiveness observed after priming with large doses of antigen.

Animals↗
PubMed1987

[In vitro titration of tetanus antitoxin].

In vitro methods are used as an alternative to the expensive and time-consuming official method in mice for the titration of tetanus antibodies. Numerous techniques have been developed and used for this purpose, but with mixed results. The difficulty is to get good correlation with in vivo units whatever the vaccinal status of the individual. Today, some of these serological techniques have been virtually abandoned in favor of others which are becoming widespread. RIA is still used, but only in laboratories which already have the necessary equipment and skill. It is gradually replaced by ELISA, a rather delicate technique which however has kept its promises and is amenable to further progress. Passive haemagglutination has been greatly improved by the use of turkey erythrocytes. With this modification, this technique becomes reliable and sensitive and is apparently able to give good results for a large number of sera in case of mass investigation as well as for a quick estimate of the protective level in an individual.

Agglutination Tests↗
PubMedDate not supplied

[Fluorometric titration in a method of metabolic cooperation in the differential diagnosis of mucopolysaccharidoses].

Content of intracellular glycosaminoglycans (GAG) was studied in a procedure of metabolic cooperation by means of the polysaccharides fluorimetric titration in order to differentiate between various types of mucopolysaccharidoses and to establish prenatal diagnosis of these diseases. The procedure involved electrostatic interaction of fluorochrome 4,6-diamidino-2-phenylindol. HCl with GAG's. As compared with the standard radiometric method of metabolic cooperation the procedure developed exhibited higher sensitivity, which is especially important for differentiation of the mucopolysaccharidoses III (A, B, C, D) and for prenatal diagnosis of these diseases.

Diagnosis, Differential↗
PubMed1988

Detection and titration of class-specific antisperm antibodies in serum using an enzyme-linked immunosorbent assay.

An antisperm antibody enzyme-linked immunosorbent assay (ELISA) that uses whole unfixed sperm and detects immunoglobulin G (IgG) and IgA antibodies in serum was developed. Donor sperm were washed and plated on poly-L-lysine-treated microtiter plates. The patient's sera were diluted to concentrations of 1:4 to 1:256 and incubated with sperm. Positive and negative sera had been previously tested for IgG antisperm antibody activity with a radiolabeled antiglobulin assay. Samples were considered positive when the mean absorbance of triplicate wells was greater than 2 SD above the pooled negative mean. Intra-assay variation was 7.9 and 9.6% for pooled negative and positive controls, respectively. Identical titers of control positive serum were consistently detected. A correlation of 0.83 was observed between ELISA IgG serum titers and radiolabeled antiglobulin results (N = 12). All negative samples tested negative in both assays (N = 21). Some serum samples showed IgA antisperm antibodies. Determination and titration of class-specific antibodies in serum should facilitate initial screening and follow-up of patients at risk for antisperm antibodies.

Enzyme-Linked Immunosorbent Assay↗
PubMed1979

Continuous monitoring of free fatty acid release from adipocytes by pH-stat titration.

A methods for direct and continuous monitoring of free fatty acid release in adipocyte suspensions is described. Using a pH-stat apparatus the protons from the released free fatty acids are continuously titrated and the accumulated amount of OH- added is monitored on a recorder against time, the slope thus indicating the rate of free fatty acid release. Sinc pH is kept constant, an incubation medium with a low buffering capacity can be used, which gives the method a high sensitivity. Under the conditions described, free fatty acid release from 5% of maximal norepinephrine stumulation of rat adipocytes can be accurately measured and the kinetics can be followed over extended periods of time.

Adipose Tissue↗
PubMedDate not supplied

Analysis for total sulfite in foods by using rapid distillation followed by redox titration.

A rapid and accurate analysis for total sulfite as sulfur dioxide has been developed for foods and food products. The method, which combines a selective distillation cleanup procedure with the selective redox titration of sulfite ion by iodine, has been applied to a variety of foods and food products over a period of time with no significant interference encountered in any matrixes other than garlic and leeks. For the foods analyzed, the method typically shows a detection limit of 10 ppm, a relative standard deviation of 7.5% (compared with 10.4% for similar matrixes by the Monier-Williams method), and recoveries of 97.9 +/- 6.4%. Comparison of results for this method with those obtained using the Monier-Williams method showed a mean value for the distillation/titration method of 241 ppm compared with 242 ppm for the Monier-Williams method. A correlation of 0.991 and odds of a difference between methods of 10.7% (Student's paired t-test (1-alpha) X 100) were obtained for those matrixes where no interferences were encountered with either method.

Food Additives↗
PubMed1985

Dose-titration studies of ivermectin against experimental Ancylostoma caninum and Uncinaria stenocephala infections.

Dose-titration trials of ivermectin were conducted on pups with dual experimental infections of 4th-stage larvae or adult Ancylostoma caninum and Uncinaria stenocephala. Ivermectin was administered orally or subcutaneously at dosages of 0.006, 0.012, or 0.024 mg/kg of body weight. Maximal or near maximal (greater than or equal to 96% to 100%) anthelmintic effect was observed for both stages of development for each hookworm species by either route of administration at a dosage of 0.024 mg/kg. Responses for all of the aforementioned categories were linearly related to increasing log dosage of ivermectin, with common slopes (regression coefficients). Regression analysis also provided estimates of the minimal dosages required to produce maximal reduction in worm burden for each stage, species, and route of administration. The estimated ivermectin dosages for maximal efficacy ranged from a low of 0.014 mg/kg for adult A caninum by oral treatment to 0.044 mg/kg for 4th-stage larvae of U stenocephala by oral treatment.

Administration, Oral↗
PubMed1985

Effects of single and repeated daily injections of morphine, clonidine and l-nantradol on responding of squirrel monkeys under escape titration.

Lever pressing of monkeys was maintained under a titration schedule in which responses decreased shock intensity which otherwise was increased at a fixed rate. The opioid morphine, the antihypertensive clonidine and the cannabinoid l-nantradol each resulted in a dose-related increase in shock intensity, although l-nantradol and clonidine were 10 to 30 times more potent than morphine. Morphine and l-nantradol resulted in markedly higher shock intensities only at doses that severely disrupted responding, whereas clonidine resulted in higher shock intensities over a broader dose range without disrupting responding. Marked tolerance developed for the shock-increasing effects of morphine (3.0 mg/kg) and l-nantradol (0.3 mg/kg) within 10 to 15 sessions, but only partial tolerance developed for shock-increasing effects of clonidine (0.3 mg/kg) after up to 35 sessions. The shock-increasing effects of chronically administered clonidine were antagonized by the alpha-2 adrenoceptor antagonist yohimbine but not by the alpha-1 adrenoceptor antagonist prazosin. When effects of acute injections were redetermined after 1 month without drug, the effects of clonidine, but not morphine or l-nantradol, were the same as before chronically administered drug. The influence of behavioral processes on the long-lasting effects of drugs seemed greater for morphine and l-nantradol than for clonidine.

Analgesics↗
PubMed1985

Effects of picenadol (LY150720) and its stereoisomers on electric shock titration in the squirrel monkey.

The mixed-action opioid picenadol (LY150720) is a racemic mixture whose resolution results in a stereoselective separation of agonist and antagonist activity. The effects of picenadol, its dextrorotatory isomer (LY136596) and morphine were studied alone and in combination with naloxone in squirrel monkeys responding under a schedule of electric shock titration. Shock intensity was scheduled to increase at 15-sec intervals in 30 steps from 0 to 5.5 mA. Completion of a fixed ratio 5-response requirement terminated the shock for a 15-sec time-out period after which shock resumed at the next lower intensity. Picenadol (0.1-17.5 mg/kg), the d-isomer (0.3-3.0 mg/kg) and morphine (0.3-5.6 mg/kg) produced dose-related increases in the intensity at which monkeys maintained the shock without decreasing responding in the presence of shock. Shock intensity increases produced by picenadol occurred over a broader dose range than with either the d-isomer or morphine. Increases in shock intensity produced by picenadol, the d-isomer and morphine were blocked by naloxone (0.001-1.0 mg/kg), although the effects of picenadol were less susceptible to antagonism. The effects of the levorotatory isomer of picenadol (LY136595) were also examined alone and in combination with morphine. The l-isomer (0.1-10.0 mg/kg) did not alter shock intensity when administered alone; however, in combination with morphine it produced a dose-dependent antagonism of the effects of morphine. The l-isomer was less potent than naloxone in this respect. These data support previous suggestions that the antinociceptive properties of picenadol arise from mu agonist actions of the dextrorotatory isomer and that the levorotatory isomer acts to limit the efficacy of the racemate.

Analgesics↗