Guide for the Care and Use of Laboratory Animals

This chapter presents basic concepts related to avian clinical biochemistry. Avian medicine and surgery is recognized as an official specialty in veterinary medicine in three continents: Europe, Australia, and North America. The increasing demand for veterinary care for individual birds with a high sentimental or economical value and efforts to conserve endangered species facilitated this awareness. The introduction of micromethods in clinical laboratories and the public demand for veterinary care for individual birds have removed many obstacles of this field. This chapter begins with discussing how blood samples of birds can be collected in the most efficient way. The chapter then discusses starvation, flight, and postprandial effects. The chapter also elaborates the biochemistry of plasma proteins, renal function, and hepatobiliary disease in birds. The chapter emphasizes that all efforts should be made to obtain a blood sample before any treatment is given. Treatments administered before samples are collected may severely affect plasma chemical values, which may jeopardize a correct diagnosis at a later stage. The time interval between restraint and blood sampling should be kept to a minimum to prevent stress-associated changes in clinical chemistry parameters. Blood samples should be obtained before an extensive clinical examination is performed to avoid iatrogenic changes in the samples.

Avian Clinical Biochemistry

Seven women with gallstones were given 0.75 to 4.5 g per day of chenodeoxycholic acid, a primary bile acid, to promote micellar solubilization of cholesterol in bile. In Case 1 three stones that had remained unchanged in size during six years of observations disappeared after six months of treatment. A single stone in Case 2 and multiple calculi in Cases 3 and 4 progressively grew smaller during 14 to 22 months of chenodeoxycholic acid administration. Gallstone size did not change in the other three. Chenodeoxycholic acid and total bile acid pool sizes (measured in two patients), which were reduced before therapy, were markedly expanded by chenodeoxycholic acid, and the ratio of bile acids and lecithin to cholesterol in bile increased in all patients. Liver function and morphology remained normal; moderate dose-related diarrhea occurred. Chenodeoxycholic acid may offer medical treatment for cholesterol cholelithiasis in man.

Dissolution of cholesterol gallstones by chenodeoxycholic acid.

Publisher Summary This chapter reviews the sequence of cellular and other changes during cancer development in selected sites in experimental animals and in humans. It highlights the similarities and differences among the carcinogenic processes and discusses the evident generalities and working hypotheses derived from the analyses. It also discusses some perspective concerning the possible relationship of carcinogenesis to other types of chronic pathological processes such as some forms of adaptation and evolution. Major emphasis is given to three sites—namely, skin, liver, and breast. Several other sites or types of neoplasms are also discussed in the chapter, including urinary bladder, brain, kidney, uterine cervix, and foreign-body sarcoma. It focuses on the development of cancer with chemicals in experimental animals and in humans. To date, the major evidence for a beneficial role for new cell populations occurring during the preneoplastic phase of carcinogenesis concerns the liver. However, it seems appropriate to explore other systems from this point of view. In other organs or tissues, appropriate physiological or environmental factors should be sought as possible influences on early carcinogen-induced new cell populations. These influences might well constitute naturally occurring “promoting” environments in at least some carcinogenic process.

The sequential analysis of cancer development.

Effect of Feed on the Composition of Milk Fat

Adaptive changes in enzyme activity and metabolic pathways in adipose tissue from meal-fed rats.

Glycogen metabolism in meal-fed rats and chicks and the time sequence of lipogenic and enzymatic adaptive changes.

Mechanism of the cholesterol-depressing effect of pectin in the cholesterol-fed rat.

The effect of corn oil, coconut oil, and medium-chain triglyceride (MCT, a glyceride mixture consisting almost exclusively of fatty acids of 8 and 10 carbons in length) ingestion on lipid metabolism was studied in chicks. In chicks fed cholesterol-free diets, MCT ingestion elevated plasma total lipids and cholesterol and depressed liver total lipids and cholesterol when compared to chicks receiving the corn oil diet. As a consequence of the opposite effects of MCT ingestion on plasma and liver cholesterol and total lipids, the plasma-liver cholesterol pool was not altered. When cholesterol was included in the diets, dietary MCT depressed liver and plasma total lipids and cholesterol as compared with corn oil, consequently also lowered the plasmaliver cholesterol pool.

Gilbert A. Leveille

Papers

Adaptive changes in enzyme activity and metabolic pathways in adipose tissue from meal-fed rats.

Glycogen metabolism in meal-fed rats and chicks and the time sequence of lipogenic and enzymatic adaptive changes.

Mechanism of the cholesterol-depressing effect of pectin in the cholesterol-fed rat.

Influence of medium-chain triglycerides on lipid metabolism in the chick.

Influence of Dietary Protein Level on Serum Protein Components and Cholesterol in the Growing Chick