Horses

This chapter will review and contrast platelet physiology of various animal qrecies. Additionally, where it contributes to understanding physiologic responses of platelets, platelet function defects will be discussed. Specific species discussed include horse, cow, sheep, goat, dog, cat, pig, rabbit, rat, mouse, Guinea pig, and bird. 

The ultrastructure of horse platelets is similar to that of human platelets (White et al. 1976). Features include a flattened discoid shape, a circumfiential band of microtubules, an open canalicular system, alpha granules, mitochondria, dense bodies, and glycogen particles. Compared to human platelets, horse dense bodies are analler and alpha granules are larger and stracturally more complex. The serotonin content of horse platelets is similar to that of human platelets. Horse platelet membrane proteins have been evaluated by polyacrylamide gel electrophoresis and glycoprotein llbllfe has been characterized and monoclonal antibodies have been produced (Lipscomb et al. 1995 Pintado et al. 1995). 

Adhesion of horse platelets to subendothelial collagen has been investigated using the Baumgartner perfusion method (Weiss et al. 1990). Bodi the total surfiice area of subendolhelium covered by platelets and the surfece area covered by platelet thrombi were 

Endotoxin induces horse platelet aggreption, however, the effect of endotoxin is indirect requiring the presence of neutrophils (Jarvis et al. 1994). The leukocyte-dependent initiator of endotoxin-induced platelet aggreption is PAF (Jarvis et al. 1996). 

Horse platelets contain a large nonmetabohe pool of serotonin and adenine nucleotides within dense bodies (White et al. 1976). Calcium ionophore (A23187) and high doses of thrmnbin (0.4 unitsAnl), but not collagen, ADP, or arachadonic acid, induced secretion of ATP and/or C-serotonin (Weiss et al. 1990, Boudreaux et al. 1988). 

---

ON A alkylating agents, intercalating agents, wrong substrates (Trofan horses, e.g, S-fluorouracil)... 

This enzyme Is widely distributed, more particularly in plants. Three important sources of the enzyme are horse-radish, turnips and milk. Peroxidase is capable of activating both hydrogen peroxide and a suitable substrate so that the latter is oxidised, although hydrogen peroxide alone may be incapable of affecting this change. It sometimes happens that hydrogen pcr-... 

Nitriles react with ammonia, or primary or secondary amines in the presence of an acid catalyst to give amidines (Scheme 26) (75, 77, 81). The catalysts used are hydrochloric acid and aluminium chloride. The amidines are anthelmintics for animals such as sheep, goats, cattle, horses, and Swine. 

It IS no accident that sections of our chair cyclohexane drawings resemble saw horse projections of staggered conformations of alkanes The same spatial relationships seen m alkanes carry over to substituents on a six membered ring In the structure... 

A sample of the protein, horse heart myoglobin, was dissolved in acidified aqueous acetonitrile (1% formic acid in HjO/CHjCN, 1 1 v/v) at a concentration of 20 pmol/1. This sample was injected into a flow of the same solvent passing at 5 pl/min into the electrospray source to give the mass spectrum of protonated molecular ions [M + nH] shown in (a). The measured ra/z values are given in the table (b), along with the number of protons (charges n) associated with each. The mean relative molecular mass (RMM) is 16,951,09 0.3 Da. Finally, the transformed spectrum, corresponding to the true relative molecular mass, is shown in (c) the observed value is close to that calculated (16,951.4), an error of only 0.002%. 

A good LC/MS instrument routinely provides a means for obtaining the identities and amounts of mixture components rapidly and efficiently. It is not unusual to examine micrograms or less of materia). LC/MS is used in a wide range of applications, including environmental, archaeological, medical, forensic, and space sciences, chemistry, biochemistry, and control boards for athletics and horse racing. 

The first pet food, a baked mixture of meat, vegetables, and wheat flour, was produced in the late 1800s. Early canned dog foods were composed mostly of meat from horses or dead stock. In the 1950s, high quaUty, nutritionally balanced, oven-baked, and pelleted dog foods became popular with dog owners and provided the most economical and satisfactory sources of dog nutrition. The extmsion process for pet foods was developed in 1954 and by 1957 extmded dog food had become the nation s leading dry pet food. 

J. V. Noble, The Forgey of Our Greek Bronze Horse, The MetropoHtan Museum of Art Bulletin, New York, 1968, pp. 253—356. 

Fig. 4. FSH receptor-binding potencies of equine FSH ( ), eCG purified from pregnant mate s semm (O), and endometrial cups (A). Receptor-binding in ceU membrane fractions, B/Bq from (a) horse, (b) calf, and (c) rodent testes (40). Courtesy of Butterworth-Heinemaim.

Most nuts for commercial use are characteri2ed by high oil and protein contents (see Proteins) as well as a low percentage of carbohydrates (qv). However, some varieties, mostly inedible tree nuts such as acorn, horse chestnut, and chufa, contain at least as much sugar and/or starch as protein. The edible water chestnut is also in this category, as is the cashew nut, which contains starch in addition to a rich store of oil. The proximate composition of a number of nuts and of some nut products are given in Table 2 (3). 

Less mechanization is used on smaller tracts of individually owned land, where the terrain is mountainous or otherwise difficult to reach, or where thinning as opposed to clear-cutting is the preferred silvicultural practice. The harvesting operation maybe done by the landowner or small contractor using chainsaws and tractors. In some operations where minimal damage to the forest is critical, horses may be used. Sale of pulpwood to the mill operation is usually through dealers. 

Avitrol [504-24-5] (4-anHnopyridine) (24), mp 155—158°C, bp 273°C, has repeUent—toxicant properties for birds and is classed as a severe poison and irritant. This secondary bird repeUent can be used as a broadcast bait, causing uncoordinated flight and distress caUs and escape responses in nearby birds (57). A reevaluation shows lack of effectiveness of 1% baits but better control of blackbirds with 3% baits (58). Suspected contamination of drinking water with 4-aminopyridine has been reported in toxicosis of Brahman catde and horses (59). 

In 1956 selenium was identified (123) as an essential micronutrient iu nutrition. In conjunction with vitamin E, selenium is effective iu the prevention of muscular dystrophy iu animals. Sodium selenite is adrninistered to prevent exudative diathesis iu chicks, a condition iu which fluid leaks out of the tissues white muscle disease iu sheep and infertility iu ewes (see Eeed ADDITIVES). Selenium lessens the iacidence of pneumonia iu lambs and of premature, weak, and stillborn calves controls hepatosis dietetica iu pigs and decreases muscular inflammation iu horses. White muscle disease, widespread iu sheep and cattle of the selenium-deficient areas of New Zealand and the United States, is insignificant iu high selenium soil areas. The supplementation of animal feeds with selenium was approved by the U.S. EDA iu 1974 (see Eeed additives). Much of selenium s metaboHc activity results from its involvement iu the selenoproteia enzyme, glutathione peroxidase. 

Veteriaary uses of sodium iodide iaclude the treatment of horses, catde, sheep, swiae, and dogs for various afflictions (see Veterinarydrugs). 

Levamisole. The racemic mixture of the d and / isomers of tetramisole [6649-23-6] was first described in 1966. It is used as an anthelmintic against a wide variety of nematodes, including lungworms, of mminants, swine, horses, dogs, and poultry. Anthelmintic activity resides in the /-isomer, levamisole [14769-73-4], the form used. 

Carbon disulfide (qv) is used, in combination with other orally administered anthelmintics, by stomach tube for hots Gastrophilus sp. larvae) and ascarids (roundworms) of horses. 

Phenothia2ine [58-37-7] (thiodiphenylamine) is used orally against intestinal nematodes of mminants and horses. It is used with occasional gastrointestinal upset, hemolytic processes, and photosensitivity. It is used routinely at low concentrations on horse farms to suppress the egg production of intestinal parasites (strongyles) and thus limit pasture contamination and transmission (4). 

The classic example of an antiinflammatory dmg is aspirin [50-78-2], acetosahcyflc acid, an effective analgesic for many years. It is well tolerated by the dog and the horse, but is relatively toxic to cats. Under the proper clinical circumstances, it can be used for prolonged therapy in chronic inflammatory diseases such as arthritis. Rimadyl is presently used. 

Toxicity. Vitamin D toxicity was known as eady as the year 1429 (217). Accidental toxicity has been reported in monkeys, dogs, horses, pigs, chinchillas, and humans, and particulady in catde when extremely high doses of vitamin D have been used to treat milk fever. 

---