Hatching and Postembryonic Development of Streptocephalus Dichotomus Baird (Crustacea : Anostraca)

Summary Hatching and postembryonic development of Streptocephalus dichotomus have been studied. Only dried eggs hatched in the laboratory. Hatching is influenced by desiccation and temperature. Drying for 10 or 20 days and temperature of 30° C seem to be favourable for S. dichotomus eggs to hatch. In S. dichotomus immersion in water up to 120 cm depth has no effect on hatching.Fifteen larval stages are involved in postembryonic development and sex differentiation appears at the eighth larval stages and becomes more pronounced in later stages. S. dichotomus takes 28 days to attain its adult structure in the laboratory at room temperature.This work formed part of the thesis submitted to the University of Madras for the award of the Degree of Doctor of Philosophy in 1970.     

Latex bread technique for detection of the plaque-forming cell response to teratocarcinoma tumor antigens

A latex bead technique modified for measuring the plaque-forming cell (PFC) response to teratocarcinoma tumor antigens in syngeneic animals is described. With this method one can detect both the primary (IgM) and the secondary (IgG) immune response to tumor antigens. Optimal detection of the PFC response depends on the proper ratio of sheep red blood cells to latex beads and the dose of tumor cell antigen used for immunization. The presence of fetal calf serum interfered with immunization of animals and the coating of the latex beads with the tumor cell antigens. The plaques obtained in response to immunization with teratocarcinoma cell antigens varied in size, probably reflecting the complex immune response to more than one class of antigens on tumor cells.     

Uptake and retention in suckling rats of51chromium fed with human milk or infant formulas

Optimum concentration of Cr for infant formulas has not been established. Such components as soy protein or supplemental Fe could influence absorption and retention. Suckling rat pups were used to evaluate the influence of three commercial formulas and human milk, all of which had been incubated with⁵¹CrCl₃ for 1 h, on the uptake and retention of the added⁵¹Cr. After fasting 3 h, the pups were intubated with a single dose of 25 μCi⁵¹CrCl₃ in either a cow's milk-based formula, an Fe-supplemented cow's milk-based formula, a soy-based formula, or human milk. Six hours later,⁵¹Cr was counted in five organs, thymus, blood, and total urine. Absorption of⁵¹Cr was low. At 6 h, percent⁵¹Cr in blood was <0.2% of the dose, and total⁵¹Cr excretion in urine was <1.8%. The uptake and retention of⁵¹Cr and its concentration in any of the organs, thymus, blood, and urine were not influenced by different types of formula or by human milk.     

The Indignity of Relative Concepts of Animal Dignity: A Qualitative Study of People Working with Nonhuman Animals

The Swiss animal welfare legislation is considered to be one of the strictest such laws worldwide. One unique feature is the inclusion of the concept of “dignity of the creature” and, more precisely, animal dignity. We interviewed 19 people from Switzerland and Germany about their concepts of animal dignity. Thereby, we investigated whether the very specific concept of the Swiss law is reflected in the minds of those who work with nonhuman animals on a daily basis. The results of our qualitative interviews revealed an awareness of the legal term among Swiss interviewees, but their personal concepts of animal dignity were not based on or similar to the legal definitions. The interviewed participants presented a broad range of concepts, including: similarities to human dignity, replacing concepts such as respect or integrity, and context-dependent, contingent forms of dignity. The applicability or usefulness of animal dignity was questioned by several participants; many judged it to be confusing or difficult. Therefore, we conclude by discussing animal integrity as an alternative concept that reflects the interviewees’ ideas of treating nonhuman animals in a respectful and appropriate way, and at the same time does not have the strongly metaphysical connotations of a concept such as human dignity.     

Interleukin-1α-induced changes in chromium-51 absorption, tissue retention, and urinary excretion in rats

The effects of interleukin-1 alpha (IL-1α) on chromium-51 absorption, tissue retention, and urinary excretion were studied in adult male Sprague-Dawley rats. Ten rats were deprived of food for 12 h, injected intraperitoneally with mouse recombinant IL-1α (1 Μg/kg of body weight in phosphate-buffered saline [PBS]) or control (0.1% bovine serum albumin [BSA] in PBS). Two hours after dosing with the IL-1α, rats were fed 50 ΜL (200 ΜCi, 0.36 Μg Cr) of⁵¹CrCl₃ by micropipet. Blood was collected from the tail at 0.25, 0.5, 1, 2, and 4 h. Six hours after dosing with⁵¹CrCl₃, rats were exsanguinated and blood and tissues were sampled. The IL-lα significantly decreased chromium-51 in blood, urine, and some tissues compared to the control. The decreased absorption, retention, and urinary excretion of chromium-51 from⁵¹CrCl₃ in this study may be due to IL-1α-mediated increases in the production of prostaglandins and/or decreased production of gastric acid.