Experimental studies chick

Marzullo, A., Vacca, A., Roncali, L., Pollice, L. and Ribatti, D. (1998). Angiogenesis in hepatocellular carcinoma an experimental study in the chick embryo chorioallantoic membrane. Int. J. Oncol. 13, 17-21. 

Tyler, M.S. 1983. Development of the frontal bone and cranial meninges in the embryonic chick an experimental study of tissue interactions. Anat. Rec. 206, 61-70. 

Although riboflavin can be assayed more readily by chemical or microbiological methods than by animal methods, the latter are preferred for nutritional studies and as the basis of other techniques. Such assays depend upon a growth response the rat or chick is the preferred experimental animal. This method is particularly useful for assaying riboflavin derivatives, since the substituents frequently reduce or eliminate the biological activity. 

Hartenbower DL, Coburn JW (1972) A model of renal insufficiency in the chick. Lab Anim Sci 22 258-261 Ishidoya S, Morrissey J, McCracken R et al. (1995) An-giotensinll receptor antagonist ameliorates renal tubulointerstitial fibrosis caused by unilateral ureteral obstruction. Kidney Intern 47 1285-1294 Klahr S, Morrissey JJ (1997) Comparative study of ACE inhibitors and angiotensinll receptor antagonists in interstitial scarring. Kidney Intern 52, Suppl 63 111-114 Sancho JJ, Duh Qy, Oms L et al. (1989) A new experimental model for secondary hyperparathyroidism. Surgery 106 1002-1008... 

Studies with animals have revealed an interesting pattern of relahorLships involving Se and vitamin E nutrition. In chicks, experimentally induced deficiencies in both S5e and vitamin E result in exudative diathesis, muscular dystrophy, and pancreatic atrophy. The first two problems can be prevented by vitamin E... 

In several studies, the activity of the alkaline phosphatase was foimd to be reduced in bones from zinc-deficient rats, pigs, cows, chicks, turkey poults, and quails (91). The activity of alkaline phosphatase can be reduced also in the intestine, kidneys, and stomach in experimental animals because of zinc deficiency. There may not only be a loss of activity attributable to a lack of suflBcient zinc for maintaining the enzyme activity, but the amount of apoenzyme present appears to be diminished because of either a decreased synthesis or an increased degradation. Inasmuch as a lowering in the activity of this enzyme in intestinal tissue and in the plasma is observed before any sign of a lowered food intake is evident, it is concluded that the loss of enzyme activity is directly attributable to zinc deficiency. 

Unexpected findings with animal feeds poor in inorganic arsenic and speculation of the possible essentiality of arsenic due to its position in the Periodic Table below phosphorus and next to selenium (both of which are known for their essential properties), led to the initiation of plans to study arsenic deficiency in experimental animals. Some earlier experiments, however, were unsuccessful as initially it was impossible to prepare correct arsenic-deficient diets. This was later achieved by Anke and coworkers (Anke et al. 1976a, b, 1987, 1990, 2001) in studies with goats and minipigs, and by researchers of the U S Department of Agriculture with rats, chicks and hamsters (Nielsen et al. 1975 cited in Uthus 1992, and reviewed by Uthus 1992, 1994, and Nielsen... 

In three studies reviewed by FAO/WHO (1994) on phosalone and 2-PAM methylsulfate in mice, P2S in rats, and obidoxime in mice, all appeared effective, although various aspects of the design of the. studies were not optimal. Oximes (PAM or obidoxime) in combination with atropine were successful in rats experimentally poisoned with pyrazophos, and there was some indication that repeated dosing was required for optimal antidotal efficacy (FAO/WHO, 1993). In a rat study of experimental terbufos poisoning, little benefit was observed from PAM and atropine (FAO/WHO, 1991). In rat studies on triazophos, combinations of atropine. sulfate and 2-PAMI or atropine sulfate and obidoxime were successful as experimental therapies (FAO/WHO, 1994). The effects of oximes in profenofas-poisoned chicks and mice were reported to be limited, as expected, although atropine was effective (FAO/WHO, 1991). 

Evidence (104,116) suggests that D-tryptophan is not fully utilized by human subjects and may have harmful effects. Further studies showed that D-tryptophan did not maintain nitrogen balance in normal young men (106), and in another study (117), urine from normal human subjects, after ingestion of D-tryptophan, contained a considerable portion of this compound as well as D-kynurenine. In contrast, the rat utilizes D-tryptophan completely however, food intake is significantly less in D-tryptophan-fed rats than in rats fed a diet containing L-tryptophan (110). The metabolic conversion of the D- to the L-enantiomer takes place in the rat liver and kidney D-amino acid oxidase plays a key role in this conversion (109). Indole pyruvic acid can be converted to L-tryptophan by a stereospecific transaminase apparently absent in humans The chick, on the other hand, utilizes only 7-40% of the D-tryptophan (82,83,110, 113). This wide range of values is probably due to different experimental conditions. D-tryptophan and... 

L-Amino acids are the naturally occurring form both in proteins and as free amino acids, and the ability of different experimental animals to use different optical isomers of the amino acids has been studied. The chick is only able to use the L-form of threonine, isoleucine and valine but can use D- and L-leucine equally. It can use both D- and L-tryptophan, although the D-form is less effective (see Fisher, 1954). This probably relates to the presence of specific racemases that enable certain D- and L-interconversions to take place. Factors that affect the requirements for specific amino acids which are particularly pronounced in avian species are summarised in Table 2.3. 

Vitamin E plays many roles essential to maintenance of health in poultry. The chick is an excellent experimental animal for study of vitamin E because this vitamin is concerned in the normal functioning of many different tissues in the chick and is retpiired for prevention of a number of different deficiency diseases, the development of which depends upon the particular environmental and dietary conditions prevailing during the conduct of the experiments. The studies with chicks show that in the nutrition of poultry in health and disease vitamin E has a dual role, acting both as a nonspecific, biological antioxidant and also as a true vitamin in two or more apparently specific roles. 

Human CRBN encodes a 442-amino acid protein that had been reported to interact with DDBl in a proteomic analysis [13]. However, the functional relevance of this interaction was unclear at that time. DDBl is a component of E3 ubiquitin ligase complexes [ 14]. Molecular biological and biochemical studies ultimately showed that thalidomide binds to CRBN and inhibits the associated ubiq-uitin ligase activity. From extensive experimentation with zebrafish and chicks, Handa and coworkers demonstrated that these interactions are responsible for the teratogenic effects of thalidomide. 

As in the case of chicks, various methods have been used to treat amphibians with retinoids and for two experimental purposes first, to study early development, and second, to study limb development and regeneration. Obviously, these two types of experiments involve treatment at widely differing stages, and a large number of different species of amphibians have been used for limb regeneration studies. 

The involvement of pericytes in physiological or tumour angiogenesis is a matter of debate. Papoutsi et al. (2000) studied the expression of pericyte, smooth muscle cell and matrix markers in experimental tumours of the mammary ductal adenoma MDA-MB231 cell line grown on chick or quail chorioallantoic membrane. Pericyte-like cells may be attracted by MDA-MB231 cells during tumour angiogenesis but failed to interact properly with endothelial cells in the tumour environment (Lauer et al. 2000). 

A few years later egg-white injury in chicks was shown to be associated with a deficiency of biotin in the tissues, despite its abundance in the diet [145]. In the same year, avidin was isolated from egg-white and its ability to inactivate biotin in vitro was demonstrated [146]. Gyorgy and Rose [235] fed rats with avidin but only found very small amounts of biotin in the faeces until the faeces were steamed. Biotin was then released from the avidin-biotin complex. As the result of further experiments, it was concluded that the fundamental cause of egg-white injury is the unavailability of biotin due to its fixation to avidin, so that biotin is not absorbed from the intestinal tract and is excreted in the faeces [237]. A similar conclusion was reached by Sullivan and Nicholls [603] who showed that when egg-white is cooked, avidin is denatured and rendered incapable of binding biotin. Egg-white injury has been produced experimentally in man and can be cured by the administration of biotin [607]. In a recent study, Peters [497] reported that raw egg-white has a direct toxic effect which is not associated with its action in causing biotin deficiency. It would appear, therefore, that further studies on egg-white injury must be more closely associated with a critical analysis of the different components of egg-white. 

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