Adult Human

Sodium chloride [7647-14-5] is an essential dietary component. It is necessary for proper acid—base balance and for electrolyte transfer between the iatra-and extracellular spaces. The adult human requirement for NaCl probably ranges between 5—8 g/d. The normal diet provides something ia excess of 10 g/d NaCl, and adding salt duting cooking or at the table iacreases this iatake. 

Calcium. Calcium, the most abundant mineral element in mammals, comprises 1.5- -2.0 wt % of the adult human body, over 99 wt % of which... 

Magnesium. In the adult human, 50—70% of the magnesium is in the bones associated with calcium and phosphoms. The rest is widely distributed in the soft tissues and body duids. Most of the nonbone Mg ", like K", is located in the intracellular duid where it is the most abundant divalent cation. Magnesium ion is efftcientiy retained by the kidney when the plasma concentration of Mg fads in this respect it resembles Na". The functions of Na", K", Mg ", and Ca " are interrelated so that a deficiencv of Mg " affects the metaboHsm of the other three ions (26). Foods rich in magnesium are listed in Table 9. 

Manganese. The adult human body contains ca 10—20 mg of manganese (124,125), widely distributed throughout the body. The largest Mg " concentration is in the mitochondria of the soft tissues, especially in the Hver, pancreas, and kidneys (124,126). Manganese concentration in bone varies widely with dietary intake (126) (see Table 10). 

The average adult human body contains 22 mg Ba, of which 93% is present in bone (47). The remainder is widely distributed throughout the soft tissues of the body in very low concentrations. Accumulation of barium also takes place in the pigmented parts of the eyes. 

The threshold of a toxic dose in adult humans is about 0.2—0.5 g Ba the lethal dose in untreated cases is 3—4 g Ba, LD q about 66 mg/kg (47). The fatal dose of barium chloride for humans is reported to be between 0.8 and 0.9 g (0.55—0.60 g of Ba) (50). However, for most of the acid-soluble salts of barium, doses greater than 1 g have been tolerated (51). Lethal doses are summarized in Table 5. Dusts of barium oxide are considered potential dermal and nasal irritants (52). 

Figure 2 Key events in fetal/neonatal life whieh predetermine reproduetive funetion of the adult human male. Note that the Sertoli eells are involved in the orehestration and eo-ordination of all of the key events. The relationship between the key events indieated and disorders of male reproduetive development and funetion are indieated in boxes.

We can end this discussion of ATP and the other important high-energy compounds in biology by discussing the daily metabolic consumption of ATP by humans. An approximate calculation gives a somewhat surprising and impressive result. Assume that the average adult human consumes approximately... 

The nutritional requirement for vitamin Bjg is low. Adult humans require only about 3 micrograms per day, an amount easily acquired with normal eating habits. However, because plants do not synthesize vitamin Bjg, pernicious anemia symptoms are sometimes observed in strict vegetarians. 

The body of an adult human contains about 2 g of Zn but, as Zn enzymes are present in most body cells, its concentration is very low and realization of its importance was therefore delayed. The two Zn enzymes which have received most attention are carboxypeptidase A and carbonic anhydrase. 

Tissue-Specific Expression. In adult rodents, PPAR.a is expressed in liver, kidney, intestine, heart, skeletal muscle, retina, adrenal gland, and pancreas. In adult human, PPARa is expressed in the liver, heart, kidney, large intestine, skeletal muscle (mostly slow-twitch oxidative type I fibers), and in cells of atherosclerotic lesions (endothelial cells, smooth muscle cells, and monocytes/macrophages). Therefore, regardless of... 

A healthy adult human body contains about 3 g of iron, mostly as hemoglobin. Because about 1 mg is lost daily (in sweat, feces, and hair), and women lose about 20 mg in each menstrual cycle, iron must be ingested daily to maintain the balance. Iron deficiency, or anemia, results in reduced transport of oxygen to the brain and muscles, and an early symptom is chronic tiredness. 

Renal excretion is the most important endosulfan elimination route in humans and animals. Biliary excretion has also been demonstrated to be important in animals. Estimated elimination half-lives ranged between approximately 1 and 7 days in adult humans and animals. Endosulfan can also be eliminated via the breast milk in lactating women and animals, although this is probably a relatively minor elimination route. No studies were located regarding known or suspected differences between children and adults with respect to endosulfan excretion. 

Table 18-1. Storage of carbohydrate in postabsorptive normal adult humans (70 kg).

The POMC protein is processed differendy in the anterior lobe than in the intermediate lobe. The intermediate lobe of the pituitary is mdimentary in adult humans, but it is active in human fetuses and in pregnant women during late gestation and is also active in many animal species. Processing of the POMC protein in the peripheral tissues (gut, placenta, male reproductive tract) resem-... 

Koka P, He K, Zack JA, Kitchen S, Peacock W, Fried 1, Tran T, Yashar SS, MerrUl JE (1995) Human immunodeficiency virus 1 envelope proteins induce interleukin 1, tumor necrosis factor alpha, and nitric oxide in glial cultures derived from fetal, neonatal, and adult human brain. J Exp Med 182 941-951... 

Breithaupt, D.E. et al.. Plasma response to a single dose of dietary (3-cryptoxanthin esters from papaya (Carica papaya L.) or non-esterified (3-cryptoxanthin in adult human subjects a comparative study, Br. J. Nutr., 90, 795, 2003. 

The liver is a wedge-shaped organ of some 1.5 kg in adult humans, which, in terms of blood circulation, is interposed between the gastrointestinal tract and the rest of the body. The blood supply to the liver is from the hepatic portal vein (80%) and the hepatic artery (20%), the former bringing a rich supply of nutrients direct from the intestinal tract and the latter supplying the liver with oxygen. Blood drains from the liver by the hepatic vein. The position of the liver enables it to act as a processor of the absorbed nutrients, and to control their storage... 

Table 5.1 Occurrence of adult human vomeronasal structures. 

Gaafar H.A., Tantawy A., Melis A., Hennawy D.M. and Shehata H. (1998). The vomeronasal (Jacobson s) organ in adult humans frequency of occurrence and enzymatic study. Acta Otolaryngol 118, 409-412. 

Johnson A.R., Josephson R. and Hawke M. (1985). Clinical and histological evidence for the presence of the vomeronasal (Jacobson s) organ in adult humans. J Otolaryngol 14, 71-79. 

Johnson E.W., Eller P.M. and Jafek B.W. (1994a). Calbindin-like immunoreactivity in epithelial cells of newborn and adult human vomeronasal organ. Brain Res 638, 329-333. 

Smith T.D., Siegel M.I., Burrows A.M., Mooney M.P., et al. (1998). Searching for the vomeronasal organ of adult humans preliminary findings on location, structure and size. Micros Res Tech 41, 483-491. 

Takami S., Getchell, M. and Chen, Y. (1993). Neurone-specific compounds in the receptor cells of the adult human vomeronasal organ. Neuroreport 4, 375-378. 

Trotier D., Eloit C., Wassef M., Talmain G., et al. (2000). The vomeronasal cavity in adult humans. Chem Senses 25, 369-380. 

---