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SUMMARY Experiments using animal litters as experimental units usually require a weighted analysis to allow for variation in litter size. This paper describes methods of assessing appropriate weights for fully randomized and for randomized block experiments. [ABSTRACT FROM AUTHOR]

The article offers information on neuroanatomical hypotheses. According to a researcher, stimulation is a basic inclination inherent in all living tissues towards the expression of its characteristic activity. It is also a derivative tendency in the early life history of the animal wherein it is subjected to perform random movements to various kinds of external stimulation and to the gratification of internal needs. This concept, which was developed by extensive experimentation with rats, posits that supplementation is still useful in understanding the notion of deprivation.

The article cites several animal experimentation. A researcher has discovered that albino rats which had been taken as pets were less timid and less apprehensive as opposed to those who had received infrequent handling. These animals were also known to survive thyroidectomy. Another researcher also identified that albino rats who had experienced gentle handling, stroking, and caressing or tactile simulation via strokes of a brush gained more body weight than did the nonstimulated ones. It is identified that the severity of stimulation largely contributes to this fact.

The author discusses the questions concerning relative doses of strontium (Sr)-90 in experimental animals and man. He pointed out that leveling trend in infant mortality is cannot be due to a natural minimum having been reached, not only as congenital malformations account the infant deaths. On the other hand, main argument links to the amounts of Sr-90 used in animal experiments. Furthermore, he describes the clues of unforeseen action of Sr-90, first was peak of infant mortality do not occur immediately after a nuclear test, and the other came from the work of Walter A. Muller, in which he measured the actual dose to the gonads of male mice following the injection of Sr-90.

With the use of chopped guinea-pig lung, previously perfused with Tyrode's solution, the rate and extent of uptake of antibody λ globulin has been measured using “131”I-labelled rabbit antibody. The reversibility of uptake was studied by soaking the tissue in Tyrode's solution or in a solution of unlabelled λ globulin. Uptake and wash-off of antibody resembled a process of reversible adsorption, and occurred both at low temperatures and when dead tissue was used. Wash-off of labelled antibody was more rapid in the presence of added normal rabbit λ globulin than in its absence. Simultaneous measurements were made of the degree of sensitization, defined as the ability of the tissue to release histamine on subsequent contact with antigen for a standard period of time at 37°. It was found that a plateau level of sensitization had been reached in a few minutes, when only a small fraction of the total antibody eventually taken up had been adsorbed. Under the conditions of our experiments, it was not possible to wash off the antibody sufficiently to de-sensitize the tissue. Evidence was obtained that antigen was most effective in releasing histamine when added over a broad but definite range of antigen excess. By pre-incubation of the labelled antibody with lung tissue, or by ‘screening’ in a living guinea pig, it was shown to be unlikely that sensitization was due to taking up by the lung of a specific readily adsorbed fraction of antibody. When the antibody preparation was separated by chromatography into physico-chemically distinct fractions, there were quantitative differences, but all were taken up and caused sensitization of the tissue. The mechanism of sensitization of guinea-pig lung by rabbit antibody is discussed, and is considered to be one of reversible adsorption of λ globulin at unidentified sites. [ABSTRACT FROM AUTHOR]

The methods successfully used to induce immunological tolerance in mice to a variety of antigens were applied to studies on mycobacterial antigens (whole tubercle bacilli). Mice were injected with approximately 5 × 105 living attenuated (BCG) or heat-killed virulent (H37Rv) tubercle bacilli on the 15th, 16th or 17th day of foetal life. Acid-fast bacilli were found in the lungs, spleens and livers of these mice after birth. Such mice subsequently developed normally and were not more susceptible to BCG than mice primarily infected in adult life. The immunological state of the mice exposed to mycobacteria in utero was determined by challenging 5 to 6 weeks after birth with either virulent or attenuated tubercle bacilli. These tests showed that an intra-embryonic injection of mycobacteria resulted in protective immunity and not tolerance. Furthermore, the mice also showed delayed-type hypersensitivity to mycobacteria. These results are discussed in relation to the ability of other antigens to induce immunological tolerance in mice and to the response of other animal species to mycobacteria. [ABSTRACT FROM AUTHOR]

A state of acquired immunological tolerance to bovine gamma globulin (BGG) has been observed in CBA mice injected with 10 mg. BGG within 12 hours of birth. Tolerance was demonstrated by a lack of immune elimination of 131I labelled BGG (BGG-131I) after prior challenge with Freund's adjuvant containing BGG. The degree of tolerance was found to diminish when the time between the tolerance injection and the challenge injection with adjuvant was increased. Mice were found to be tolerant 4 months after injection of 10 mg. BGG at birth but other similarly treated mice were found to be partially immune when challenged 6 months after the tolerance injection. This diminution of tolerance could be prevented by injections of antigen into adult mice whilst they were still tolerant. Precipitin and haemagglutination tests showed that antibody to BGG was present in mice shown to be tolerant to BGG by the antigen-elimination technique. The Ouchterlony double-diffusion technique showed that the mice were tolerant to one fraction of BGG but immune to at least one other fraction. The tolerated fraction of BGG was identified by means' of starch-gel electrophoresis. [ABSTRACT FROM AUTHOR]

Immuno-conglutinin has been stimulated in rabbits after infection with Listeria monocytogenes, Salmonella typhi-murium and other bacterial species. Infection of rabbits with Western Equine Encephalomyelitis, Hammon Reeves, Murray Valley Encephalitis and Aedes trivittatus viruses also stimulated the production of this substance. The most marked immuno-conglutinin response followed infection of rabbits with Trypanosma brucei. Rickettsia burneti infection in guinea pigs produced a biphasic immunoconglutinin response, the first phase being coincident with the rise of antibodies to the Phase II antigen and the second phase with the retarded rise of antibodies to the Phase I antigen. In mice also, the immuno-conglutinin level was raised following infection with Escherichia coli, Salmonella typhi-murium and other bacterial species. [ABSTRACT FROM AUTHOR]

The article examines the effect of Bordetella pertussis vaccine on the development of experimental thyroiditis in rats immunized by the intra-lymph node route or into a hind footpad. Pertussis vaccine has been shown to have an enhancing effect on the development of experimental autoallergic diseases in laboratory animals. The results indicate that moderate to severe thyroiditis may be established within 8 days with the production of circulating thyroglobulin antibody but not thyroid complement fixing antibody.

The article discusses the evaluation of drug safety and the techniques for evaluating the chemicals used in these drugs. It is stated that the assessment of the utility and safety of a potential drug starts with the first pharmacologic studies in animals and goes through all of the animal experimentation period. The safety tests in humans consists of metabolic and pharmacologic investigations, which require one or two doses of the agent. In chronic studies the drug is administered continiously for weeks or months.

The article discusses the role of exotic animals in the advancement of biomedical research. Some of the exotic animals that have contributed significantly to advances in biomedical research are opossum, eel, shark, ground squirrel, alligator, snake, clam, camel, kangaroo rat, chimpanzee and baboon. Species of chimpanzee is ideal for studies on the rocket-propelled sled. As chimpanzees are very expensive to buy, Air Force personnel use black bear which can be obtained domestically and at a lot less cost. Dogfish shark has been enlisted as a subject in addition to many other species of animals to understand the physiology of renal function. Squid and crab have been used to study nerve physiology.

The article reports on the use of landmarks in avian orientation by bank swallows. It shows the results of a series of experiments designed to identify the distance from home at which landmarks are recognized by one species of passarine birds, the bank swallow. For testing, the use of landmarks by bank swallows from five colonies in the Lake Cayuga region were released at Burdett, New York, is utilized. According to the authors, the presented experiments indicate that most bank swallows are familiar with landmarks located 5 km or less from the home bank and that they use cues other than landmarks to home from distances greater than 5 km.

The article discusses the implications of chemical factors in the success, reproductibility, and reliability of research involving laboratory animal subjects. It identifies the components that contain or contribute chemicals to the environment including air, water, and food that provides the nutritional requirements essential to the successful growth and reproduction of laboratory animals. It notes that specific chemicals modify or potentially can modify the biomedical responses of laboratory animals.

The article reports on the failed attempt of two legislators to create a law that would limit or ban the use of animals in secondary school classes in California. Both bills by state senator Albert Rodda and assemblyman Jerry Lewis were defeated after efforts were mounted by the California Medical Association. Rodda wants to ban the use of animals in classrooms while Lewis wants a legislation that school experiments involving animals be conducted under the supervision of a life science teacher, physician, dentist or veterinarian. Meanwhile, the National Society for Medical Research (NSMR) believes that the use of animals in school experiments should be limited.

The article presents information on various U.S. legislation related to the field of biosciences. The bill H.R. 13786, introduced by George P. Miller, chairman of the House Science and Astronautics Committee, will provide $150 million a year to higher education institutions for 4 succeeding years. Democrats Daniel B. Brewster and Joseph D. Tydings have introduced the S. 3240 bill, which aims to amend the Federal Water Pollution Control Act. A judge in New Jersey ruled that live animal experimentation, if properly conducted, at the high school level does not amount to needless cruelty to animals. U.S. President Lyndon B. Johnson signed a compromise version of the oceanography bill into law S. 944 on June 17, 1966.