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At least 1,711 records · Page 95Linked to original sources
PubMed1985

Effects of buprenorphine on shock titration in squirrel monkeys.

The effects of buprenorphine were examined under a shock titration procedure and compared to the effects of morphine. Under this procedure shock increased every 15 sec from 0 to 2.0 mA in 30 increments. Five responses within a 15-sec shock period decreased shock intensity by one increment. Both buprenorphine and morphine increased the level at which shock was maintained without decreasing rates of responding in the presence of shock. Buprenorphine-induced increases in median shock level occurred over a 10-fold dose range and were apparent for 6 to 12 hr. Dose-effect curves for morphine and buprenorphine were shifted to the right by prior administration of diprenorphine (0.001-1.0 mg/kg), naloxone (0.001-1.0 mg/kg) and beta-funaltrexamine (1.0-16.0 mg/kg), with the dose of antagonist required to restore responding to control levels being 1 to 2 log U larger for buprenorphine than for morphine. Buprenorphine-induced increases in median shock level were also restored to control levels when naloxone (1.0 mg/kg) was administered as much as 110 min after buprenorphine. Buprenorphine was not effective in antagonizing the effects of morphine. When a dose of buprenorphine which increased median shock level was administered once daily, median shock levels returned to control level within 6 to 15 days. When the morphine dose-effect curve was then redetermined in the presence of chronic buprenorphine, it exhibited a 10-fold shift to the right.

Animals↗
PubMedDate not supplied

Polarographic determination and aqueous potentiometric titration of cimetidine in tablets.

A method is described which uses the direct current (dc) polarographic behavior of cimetidine in a strong acid solution to determine this compound. The diffusional characteristics of the reduction wave of cimetidine in 1M HCl (about -0.8 V vs SCE) are shown, and their analytical usefulness was studied. This polarographic method was used to determine cimetidine in standard solutions ranging from 4 to 80 micrograms/mL with a coefficient of variation of 1.3%, and was further applied to the determination of cimetidine in tablets. The results obtained by the dc polarographic method agree with those obtained by an aqueous potentiometric titration of cimetidine with HClO4 and estimation of the end point by the Gran graphic method.

Cimetidine↗
PubMed1978

[Biological titration of antidiuretic activity of ovine plasma].

We studied a relationship of the antidiuretic hormone to the level of urea in the ovine blood. An antidiuretic activity of the ovine blood plasma before and after 36-hour fasting was determined by biological titration on 22-day-old rats. Optimum control doses were calculated as follows: 1.0 muU for pitressin, 2.5 muU for lysine-vasopressin and 0.1 muU for arginine-vasopressin, these doses securing 80-85% antidiuretic activity. The antidiuretic activity of the ovine blood plasma reached 90, 70, 46% before fasting and 58, 59, 46% after 36-hour fasting, in comparison with the control doses. It can be concluded from the results that there is no relationship between the antidiuretic activity of the ovine plasma and an increased urea concentration in the blood during the first days of fasting (36 hours).

Animals↗
PubMed1979

Effect of protein on titrimetry of bicarbonate, titratable acid, and ammonium in urine.

Measurement of bicarbonate, titratable acid (HTA+) and ammonium in the urine can facilitate clinical evaluation of acid-base status. Sequential measurement of these three components by titrimetric techniques is well established, but possible interference by proteinuria has not been examined. We report the influence on these analyses of albumin and globulin, two proteins commonly observed in urine in renal disease states. The presence of these proteins in urine affects the measurement of NH4+, and to a less extent that of HTA+. The magnitude of the effect depends on the concentration and the kind of protein present. Proteins do not influence the measurement of HCO3-.

Acid-Base Equilibrium↗
PubMed1965

A rapid plaque method using vertical tube cultures for titration of viruses and neutralizing antibodies.

Standard methods for titrating and typing enteroviruses and other viruses, or for assaying antibodies against them, are based on observation of metabolic inhibition of infected cells or on direct microscopic reading of cytopathogenic effects. Incubation of cell cultures for at least a week, with two or three readings during this period, is usually required before assessment is completed. This report describes a vertical-tube method in which cell monolayers are confined to the bottom end of a serological tube; an agar overlay is used after virus or virus-serum inoculation. The reduced monolayer area allows seeding with only about 30% of the cells required for standard tube cultures, and 5% of those required for plaque assay in bottle cultures. The new method requires only a single macroscopic reading one to three days after the test is set up. This method has proved economical, simple and rapid in epidemiological studies on rapidly growing viruses of the entero-, reo-, herpes-, myxo- and poxvirus groups, and for tests of the genetic markers of live poliovirus vaccine.

Culture Techniques↗
PubMed1970

Proficiency in the detection and titration of blood group antibodies: results of an interlaboratory trial.

Twelve numbered samples of serum were distributed to 82 Canadian blood transfusion laboratories. The presence or absence of blood group antibodies in these samples was correctly reported by less than 50% of participants; inability to demonstrate the presence of weak anti-D or anti-c was responsible for most of the failures. On the other hand, about 85% of participants reported titres of anti-D and anti-Fy(a) within an acceptable range. Two proposals are made that should help laboratories achieve a high and uniform level of proficiency in antibody detection and titration.

Antibodies↗
PubMedDate not supplied

Growth and infectivity titration of virulent infectious bursal disease virus in established cell lines from lymphoid leukosis tumors.

Lymphoblastoid cell lines were investigated for susceptibility to virulent (wild) infectious bursal disease virus (IBDV) and attenuated IBDV by detection of fluorescent antigen in inoculated cells. LSCC-BK3 and LSCC-CU10 cells were susceptible to both types of IBDV; LSCC-1104-B-1 line was susceptible to only the attenuated IBDV. However, 2 lymphoid leukosis and 2 Marek's disease cell lines were refractory to growth of any type of IBDV. When the J1 strain of virulent IBDV was inoculated into LSCC-BK3 cells, intracellular and extracellular viruses began to increase logarithmically between 4 and 8 hr postinoculation and reached 10(6.3) and 10(7.3) TCID50/0.1 ml, respectively, at 72 hr. Infectivity titration and serum-neutralization tests of virulent IBDV were possible with LSCC-BK3 cells.

Animals↗
PubMed1983

A method for evaluating the statistical accuracy of in vitro virus titrations.

A method is proposed for evaluating the statistical accuracy of virus titrations based on formation of foci or plaques in monolayer cell cultures and of colonies in soft medium. It can be applied to experiments of enhancement or inhibition of virus replication and of cell transformation or lysis, even with effects of small amplitude. The method is based on simple formulae derived on the basis of Poisson's distribution of infectious particles in cell cultures. It can be used in determining the statistical significance of one result obtained in a single experiment, of the difference between two results obtained in a single experiment with the same control, and of two results obtained in two different experiments with two different controls. It offers moreover the possibility of planning experiments in order to get an expected result significant for a desired confidence limit.

Fibroblasts↗
PubMed1983

[Model UF-2 mutant of Staphylococcus aureus 209 P for titrating Vibrio cholera enterotoxin].

The identical character of the action of crude V. cholerae enterotoxin on the anaerobic dehydrogenases of the UV-2 mutant of S. aureus 209 p and the surviving culture of Ehrlich's carcinoma has been revealed. The range of this action is linked with the concentration of the toxin and varies from the stimulation of cell dehydrogenases to their complete suppression. The rapid method for the titration of the enterotoxin in the dehydrogenase suppression test with the use of the bacterial model is proposed.

Animals↗
PubMed1978

[Progress in diagnosis of gastric function: gastric secretory analysis, intragastric titration, endocrine provocation tests (author's transl)].

Diagnostic procedures for the measurement of gastric acid secretion and for the differention between several types of hypergastrinemia have been improved during the last years. An intravenous dose-response curve with increasing doses of pentagastrin resulted in 30% higher MAO compared to subcutaneously administered pentagastrin (6 microgram/kg body weight). Food-stimulated gastric acid secretions can be measured by intragastric titration; this method is used mainly in clinical-physiological studies. The different forms of hypergastrinemia may be differentiated by 3 provocation tests: calciuminfusion, secretintest, glucagontest. In atypical cases of Zollinger-Ellison-Syndrome it may be necessary to perform all 3 tests.

Calcium↗
PubMed1983

Failure of bovine complement levels measured by radial hemolysis to correlate with tube titration.

Hemolytic complement levels in 30 duplicate samples of normal bovine sera were determined by a tube titration method (CH50) and by a radial hemolysis in gel assay. Significant correlation was not observed between the values obtained by the 2 tests. This lack of correlation could be a result of considerable error observed in values obtained for duplicate samples in the CH50 method or to the relative insensitivity of the hemolysis in gel test. The hemolytic reaction in gel was found to depend on Mg2+, thus raising questions (i) about its validity in determining total hemolytic complement or (ii) about bovine C1q depending on Mg2+ rather than Ca2+ for binding to immune complexes.

Animals↗
PubMed1983

A laboratory reference vaccine to titrate immunogenic activity of antibrucella vaccines in mice.

The number of bacteria (CFU) in spleens of mice fifteen days after a standard intraperitoneal challenge of Brucella abortus, is dependent on vaccinal immune status of mice. From this observation, a control method of vaccinal activity was previously proposed, which classified the responses in relation to fixed reference values. A reference vaccine, a lyophilized formalin-killed bacterial cell suspension of B. melitensis strains H38 was prepared and titrated. From the dose response curve, the quantities giving reference values were calculated and expressed in a Unit system. This vaccine makes possible inter-laboratory comparisons of vaccinal activity, that can be expressed on the Units basis.

Animals↗
PubMedDate not supplied

[The quantitative determination of sulfhydryl and imidazole groups in proteins by the method of inversiochronopotentiometric titration].

A method is suggested for a quantitative determination of sulphydryl and imidazole groups in proteins. The method is based on the capacity of Zn2+ and Co2+ to bind selectivity with sulphur and nitrogen atoms in bioligands. The mentioned reactions are fixed by one of most sensitive methods of the electrochemical analysis, the inversiochronopotentiometric titration. The method was tested with the solutions of amino acids and proteins. The sensitivity of the method is 10(-8)M, a relative error is +/- 1.5%.

Cobalt↗
PubMed1978

[Diphtheria toxin titration using "Staphylococcus aureus" protein A (author's transl)].

The antigen-antibody reaction between diphtheria toxin and its corresponding IgG antibody may be visualized if IgG are adsorbed on the surface of S. aureus cells carrying protein A (SpA). If enough antigen is mixed with SpA--IgG, a visible agglutination occurs. On a glass slide, a rapid test can detect 0.3 Lf/ml toxin. If the mixtures are incubated overnight at 37 degrees C, the highest dilution of toxin producing agglutination is 0.01 to 0.02 Lf/ml for a given batch of toxin. The sensitivities of this or of the biological titration using the lethal effect on guinea-pigs are the same. The high sensitivity of the skin reaction was however not approached.

Agglutination Tests↗
PubMed1983

[Standardization and stability of reagents for the titration of anti-tetanus antibodies by means of the passive hemagglutination technic].

The evaluation of the antitetanus immunity in human sera is of primary importance for the carrying out of an adequate prophylaxis and treatment of tetanus. Tetan Test is a diagnostic kit for the titration of the antitetanus antibodies, by means of the passive hemagglutination technique. Tetan Test is examined under the point of view of the preparation techniques and the process and final controls which warrant the quality and the standardization of the product itself. The stability of Tetan Test, after storage at the temperatures: 67 degrees C, 52 degrees C, 37 degrees C, 22 degrees C is evaluated. The excellent results obtained allow the use of the product also in hot climates, in developing countries, where the storage at the advised temperatures is not possible.

Antibodies↗
PubMed1983

Propagation and infectivity titration of the Gifu-1 strain of chicken anemia agent in a cell line (MDCC-MSB1) derived from Marek's disease lymphoma.

Chicken anemia agent (CAA) propagated in an established cell line derived from Marek's disease (MD) lymphoma (MDCC-MSB1). When passaged 19 times in MDCC-MSB1 cell cultures, it produced anemia of the same severity in chicks as it did before passage. Titration of the infectivity of CAA was performed successfully with subcultures of MDCC-MSB1 cell cultures which had been inoculated with serial tenfold dilutions of infected material. In it, no infected cultures could be subcultured. The propagation of CAA was also proved in the MD cell line, MDCC-JP2, and the avian lymphoid leukosis (LL) cell line, LSCC-1104B1, but not in the two MD cell lines, MDCC-RP1 and MDCC-BP1, or in the two LL cell lines, LSCC-1104X5 and LSCC-TLT. No CAA propagated in cell cultures prepared from skin and muscle, liver, or brain of chick embryos, or kidney, thymus, bursa of Fabricius, bone marrow, or white blood cells of chickens.

Anemia↗
PubMed1984

[Efficacy of a new antisecretory agent (40 749 RP) on human gastric secretion induced by a meal (intragastric titration)].

An antisecretory drug of a new series, 40 749 RP, without anticholinergic or H2 receptor antagonist activities, was tested on meal-induced gastric acid secretion in 6 healthy volunteers. Gastric acid secretion and emptying of liquid were measured using intragastric titration. Oral dosages tested were 1, 2 and 4 mg/kg versus placebo. Inhibitions obtained were dose-related and expressed in percentage of the placebo values: 36 +/- 10 p. 100 for 1 mg/kg; 51 +/- 13 p. 100 for 2 mg/kg and 83 +/- 5 p. 100 for 4 mg/kg. Statistically significant correlation (p less than 0.001) was observed between maximal blood concentration of 40 749 RP and the percentage of secretory inhibition during the 90 min of the test. No change in gastrin response or in gastric emptying was observed whatever the dose.

Adult↗