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At least 19 recordsLinked to original sources
PubMed1976

A new biological assay method for histamine-sensitizing factor using survival time as a response.

A new biological assay method using survival time of mice as a graded response after histamine challenge has been developed for the histamine-sensitizing factor of pertussis bacilli. The method is relatively precise and reproducible in estimation and fairly sensitive in the validity tests of biological assay. Effect of endotoxin on the estimation by the proposed method was also investigated in case the method is applied to the control test of pertussis vaccine.

Animals↗
PubMed1992

Biological assay for tissue kallikrein: comparison with the synthetic substrate S2266.

A highly sensitive biological assay for tissue kallikrein is described, using human kininogen as substrate; and quantitation, by radioimmunoassay, of generated kinins. Using purified human urinary kallikrein as a reference standard we have correlated the kininogenase activity of kallikrein with amidase activity as measured by cleavage of the synthetic substrate S2266.

Animals↗
PubMed1992

Functional activities of synthetic anaphylatoxic peptides in widely used biological assays.

A comparison study was carried out between the modern ATP release assay (ARA) with guinea-pig platelets and the traditional guinea-pig ileum contraction assay (ICA). The biological activities of the anaphylatoxin C3a and synthetic C3a analogue peptides were determined in both assays. In dose-response curves with C3a, a human C3a peptide with the last 21 amino acids of the C terminus (C3a 56-77) and a peptide with 13 amino acids which was acylated N-terminal with the aromatic fluorenylmethoxycarbonyl group and an aminohexanoyl group (Fmoc-Ahx YRRGRAAALGLAR) were tested. The ARA turned out to be 100 times more sensitive than the ICA. In contrast to previous reports the 21 amino acid long C3a analogue peptide did not exhibit full C3a activity but only 7% (ARA) or 12% (ICA). The potentiation of biological activity in the ARA by coupling non-peptide acyl-residues N terminal to peptide C3a analogues could be confirmed with Fmoc-Ahx-YRRGRAAALGLAR in the ICA. In addition, the tri-peptide Fmoc-Ahx-LAR displayed C3a specific activity in the ICA demonstrated by desensitization experiments.

Adenosine Triphosphate↗
PubMed1991

A simple biological assay for relaxin measurement.

1. Relaxin (R) is considered a gestation hormone with an insulin-like molecular structure. Its physiological importance is significant in the reproduction process. 2. Different methods of biologically assaying R have been published but electrophysiology techniques on uterus and ileum of rat have never been used. 3. A protein fraction was obtained from ovarian tissue of the rat and used to measure electrophysiological activity in vivo and in vitro. 4. Protein recovered with R activity was similar to that in previous reports. 5. Reduction of 100% in contraction strength and 50% in its frequency was observed in ileum and in uterus respectively; it was only of 60%, but its frequency increased 43%. 6. Methodological considerations and some physiological aspects are discussed.

Animals↗
PubMed1975

A sensitive method for the biological assay of secretin and substances with "secretin-like" activity in tissues and biological fluids.

The isolated perfused pancreas is extremely sensitive to secretin and can be used to assay very small quantities of secretin. The addition of theophylline to the perfusate increases the sensitivity of the preparation 4 to 10 fold so that in a good preparation as little a 0.001 C.U. may be detected. Secretin-like activity was detected in biopsy samples of jejunal mucosa taken perorally from man, in the blood of some patients suffering from a profuse watery diarrhoea, and in a metastatic tumour obtained from one such patient. It was also observed that 1 clinical unit of secretin was equal to 4.4 Crick, Harper, Raper units.

Adult↗
PubMed1975

Structural analogs of 1alpha,25-dihydroxycholecalciferol: preparation and biological assay of 1alpha-hydroxypregnacalciferol.

The synthesis of 1alpha-hydroxypregnacalciferol, a side chain analog of 1alpha,25-dihydroxycholecalciferol (1alpha,25-dihydroxyvitamin D3), is described. Pregnenolone acetate was converted in five steps to 5-pregnen-1alpha,3beta-diol. Conversion of the diol to pregna-5,7-diene-1alpha,3beta diol diacetate followed by ultraviolet irradiation gave the corresponding previtamin derivative. Thermal isomerization, hydrolysis and chromatography then furnished the desired analog, 1alpha-hydroxypregnacalciferol. The compound was tested in vivo for its effect on intestinal calcium transport, serum calcium and phosphate levels and bone calcification, and in vitro for its effect on bone resorption. When given to intact rats, either as a single dose or in repeated daily doses, the analog even at high dose levels, exhibited no biological activity. The compound stimulated bone resorption in vitro, but only at high concentrations.

Animals↗
PubMed1975

[Biological assay of hypophyseal gonadotropins in the male rat (statistical study)].

The reproductibility, the experimental and statistical procedures of FSH and LH bioassays are studied. The estrogen pretreatment of animals increases, considerably the responsiveness and reliability of the LH bioassays. FSH levels have been determined, by the methods for parallel line assays, in the pituitary gland of normal rats and three days or seventeen days orchiectomized rats.

Animals↗