Log Dose-response Relationship Research Articles

CAFFEINE-INDUCED ULCEROGENESIS IN THE RAT

The present investigation has demonstrated that administration of caffeine alkaloid (6.25 mg/kg, 25 mg/kg, and 100 mg/kg) by stomach tube induces acute gastric ulcers in the fundus, pylorus, and antrum of fasting male and female rats. The ulcers are histologically characterized as superficial erosions of the glandular mucosa. Statistical evaluation of ulcer indices indicated a linear, log dose–response relationship for caffeine alkaloid, and a similar ulcerogenic effect in both male and female rats.

A method for the quantitative estimation of drugs on the isolated intact trachea.

A method is described for the detection and comparison of substances active on tracheal smooth muscle. Several pharmacological agents affecting smooth muscle have been tested using the technique. Sensitivity was high, results reproducible and linear log dose-response relationships obtained over a wide dosage range. The method has been used to estimate the concentrations of adrenaline, acetylcholine and histamine in test solutions of these compounds.

The log dose-response relationship for intradermal old tuberculin in tuberculous patients.

Summary There is a linear relationship between logarithm of dose of Old Tuberculin and the mean diameter of the indurated area in five patients with pulmonary tuberculosis. This finding is in agreement with the results of others for intradermal tuberculin in animals. It is suggested that the diameter of the reaction is a better index of the response than the area.

THE IN VITRO EFFECT OF PROLACTIN ON β-GLUCURONIDASE IN THE TESTIS OF THE RAT

SUMMARY The effect of prolactin on the activity of β-glucuronidase in the testis of the rat and mouse has been studied in vitro. Prolactin increased this activity, and a linear log dose-response relationship was found to exist with doses of between 0·3 and 1·2 mg. of a preparation of prolactin containing between 20 and 25 i.u./mg. The optimal conditions for this effect have been investigated. Twenty other substances have been tested; none increased the enzymic activity, but six decreased it. Possible mechanisms for this effect are discussed.

Estrogen effects on the carbonic anhydrase content of mouse uteri.

Using a sensitive manometric method, determination has been made of carbonic anhydrase concentrations in the uteri of 1) normal adult, 2) ovariectomized adult, and 3) immature mice. The enzyme content of 1) varies with the stage of the estrous cycle, being maximal at early estrus and minimal at diestrus. In contrast, rat uteri exhibit maximal content at diestrus and minimal content at estrus. In 2) the enzyme content decreases but may be restored to normal levels by estrogen administration, whereas progesterone administration leaves the content unaffected. In 3), in which the enzyme content is low, the level is increased by estrogen administration, and the log dose-response relationship is linear over a total dose range of 0.015 to 2 micrograms per mouse in a 5-day administration regimen. Progesterone inhibits the effects of estrogen in 2) and 3), and at a constant estradiol dosage (1 microgram per mouse) the concomitant administration of progesterone in graded dose gives a linear log dose-response relati...

CAFFEINE-INDUCED ULCEROGENESIS IN THE RAT

The present investigation has demonstrated that administration of caffeine alkaloid (6.25 mg/kg, 25 mg/kg, and 100 mg/kg) by stomach tube induces acute gastric ulcers in the fundus, pylorus, and antrum of fasting male and female rats. The ulcers are histologically characterized as superficial erosions of the glandular mucosa. Statistical evaluation of ulcer indices indicated a linear, log dose–response relationship for caffeine alkaloid, and a similar ulcerogenic effect in both male and female rats.

Granuloma pouch anti-inflammatory assay: some remarks on calculation and statistical analysis of results.

ABSTRACT A statistical analysis is made of the granuloma pouch assay in the rat as a quantitative method for estimating the anti-inflammatory activity of different materials. The problems of calculating the best unbiased mean and estimates of standard error and degrees of freedom on replicate experiments are studied. Use is made of established criteria for deciding whether the means to be combined are, or are not, of the same precision, and the course to follow in each case. Emphasis is laid on the verification of the hypothesis of non-linearity between response and logarithm of dose of materials (steroids) administered. Estimating equations as well as characteristic statistical parameters are presented for all steroids tested. Results of this analysis indicate that there is a linear logdose-response relationship and that the slopes of the estimating equations for all steroids assayed do not differ significantly from that for the standard. The symbol XY50 is defined to signify the calculated dose causing 50 per cent effect in a graded response assay in which the range of response has been by arithmetic conversion arbitrarily established from 0 to 100. The reliability of obtaining estimates of relative potency as ratios of different XY50 is demonstrated theoretically and illustrated experimentally.