Since the microbiological assay of the antibiotic content of serum generally requires 18 to 24 hr of incubation, results of such procedures may not become available in time to make appropriate adjustments in subsequent dosages of antibiotic. A 4-hr bioassay for determining concentrations of gentamicin in serum has been developed in which Staphylococcus aureus ATCC 6538P is used as the test orga...

To evaluate the penetration of ciprofloxacin, a new wide-spectrum oral antibiotic, into the vitreous, ciprofloxacin was administered orally to 21 patients who were scheduled to undergo vitreal surgery. Seven patients received 750 mg ciprofloxacin 4 hr before surgery (group I), seven patients received this dose 8 hr before surgery (group II), and seven patients received two 750-mg doses of oral ...

Enterotoxic capacities of 95 Yersinia enterocolitica strains isolated from fattening pigs by the use of the suckling mouse bioassay were investigated. A positive result was received for 14 strains (14.74%), doubtful for 33 strains (34.74%), while the rest of 48 strains (50.52%) did not induce the production of enterotoxins. The received results show that in the pig population there are almost 1...

Previous studies indicated that dispersal of S. carpocapsae may be enhanced in soil with earthworms. The objective of this research was to determine and compare the effects of earthworms on dispersal of other Steinernema spp. Vertical dispersal of Steinernema carpocapsae, S. feltiae, and S. glaseri was tested in soil columns in the presence and absence of earthworms (Lumbricus terrestris). Disp...

How floral colour polymorphism can be maintained in evolutionary time is still debated. In rewardless orchids, it is unknown whether rare white-flowered morphs differ in scent chemistry from pigmented morphs, and whether such intraspecific variation in floral signals may have an impact on reproductive success. We compared the chemical composition of floral volatiles emitted by white- and purple...

The retention of deoxynivalenol in noodles and bread made from naturally-contaminated flour was examined by a chemical analysis (HPLC) and bioassays. The retention level of deoxynivalenol obtained from both assays was reduced by boiling process, although only the bioassays showed it to have been reduced by baking. This study is the first to estimate the exposure to deoxynivalenol from the consu...

The ILSI/HESI Workshop on Alternatives to Carcinogenicity Testing aims to develop and apply new methods for assessment of potential carcinogenic risk to humans from various chemicals. The Workshop represents a major cooperative scientific effort. The long-term goals should be to greatly enhance the efficiency and reliability of such testing and to supplant, not just supplement, lifetime rodent ...

Statistical methods for the use of historical control data in testing for a trend in proportions in carcinogenicity rodent bioassays are reviewed. Asymptotic properties of the Hoel-Yanagawa exact conditional tests are developed and compared with the Tarone test. It is indicated that the Hoel-Yanagawa test is more powerful than the Tarone test. These tests depend on the beta-binomial parameters ...