BACKGROUND Cadmium (Cd) risk assessment presently relies on tubular proteinuria as a critical effect and urinary Cd (U-Cd) as an index of the Cd body burden. Based on this paradigm, regulatory bodies have reached contradictory conclusions regarding the safety of Cd in food. Adding to the confusion, epidemiological studies implicate environmental Cd as a risk factor for bone, cardiovascular, and...

OBJECTIVE Isocyanates (di- and poly-), important chemicals used worldwide to produce polyurethane products, are a leading cause of occupational asthma. Respiratory exposures have been reduced through improved hygiene controls and the use of less-volatile isocyanates. Yet isocyanate asthma continues to occur, not uncommonly in settings with minimal inhalation exposure but opportunity for skin ex...

A micro total bioassay system that mimics physiological processes was developed as a means of evaluating orally administered drugs. A new feature accounting for gastrointestinal digestion was added to the previous system, which consists of microintestine, microliver, and target components. The artificial micro-gastrointestinal tract employs synthetic digestive juices. The system could correc...

Most of the transport along the nephron uses membrane proteins and exhibits the three characteristics of mediated transport: saturation, specificity, and competition. Glucose reabsorption in the nephron is an excellent example of the consequences of saturation. Two classic papers by James A. Shannon and colleagues clearly show the ability of the kidney in transporting glucose and its saturation...

This paper reviews the evidence for novel physiological functions of oligosaccharides. A history of the research and development and the types of health benefits are discussed. A key property of the physiological functions lies in the indigestibility of oligosaccharides, which gives rise to fermentation in the large intestine, followed by an increase of Bifidobacteria and short-chain fatty acid...

The relative impermeability of the surfaces of leaves to water and mineral ions in solution is a condition upon which the life of terrestrial higher plants depends. However, for the investigator this feature imposes difficulties on attempts to make quantitative studies of the process of ion absorption by leaf tissue. The importance of this absorption process in the physiology of leaf cells has ...

sunn pest (eurygaster integriceps put.) is one of the major pests of wheat in iran. identification of resistantcultivars is an effective integrated pest management (ipm) strategy. to identify the genetic response of wheat and triticale to sunn pest, and determine the relationship between resistance and morpho physiological traits, eight bread wheat breeding lines/cultivars, four durum wheat lin...

Although a minor constituent of cell and tissues, sulfur is an essential element to fulfil a wide range of biological processes, and it is present in the functional groups of many biomolecules that participate to redox reactions in vivo. Cysteine, one of the two S-containing aminoacids present in proteins, contains sulfur in fully reduced form and its thiol group can undergo a range of reaction...

Poultry diets are typically supplemented with DL-2-hydroxy-4(methylthio) butanoic acid (HMTBA, or the hydroxy analog of methionine) or DL-methionine (DLM). Although HMTBA and DLM provide methionine activity, they are structurally distinct molecules with different physiological characteristics until they are converted to L-methionine. The relative rates of intestinal HMTBA vs. DLM absorption hav...

Renal ammonium excretion is increased by potassium depletion and reduced by potassium loading. To determine whether changes in potassium concentration would alter ammonia transport in the medullary thick ascending limb (MAL), tubules from rats were perfused in vitro and effects of changes in K concentration within the physiological range (4-24 mM) were evaluated. Increasing K concentration from...