Cadmium Accumulation In Tissues Research Articles

Effect of phytic acid and microbial phytase on Cd accumulation, Zn status, and apparent absorption of Ca, P, Mg, Fe, Zn, Cu, and Mn in growing rats.

Three groups of individually housed albino rats (n = 6, initial average weight = 47 g) were fed diets based on egg white and cornstarch (basal diet 8 g Ca, 5.2 g P, 0.76 g Mg, 100 mg Zn, 100 mg Fe, 50 mg Mn, 7 mg Cu, and 5 mg Cd per kilogram diet) over a 4-week period. Group I (controls) was fed the basal diet free of phytic acid (PA) and microbial phytase. In groups II and III cornstarch was replaced by 0.5% PA from NaPA (molar PA/Zn ratio approximately 5). In group III, 2,000 U of microbial phytase from Aspergillus niger per kilogram diet was added. Live weight gain, zinc status (zinc in plasma, femur, liver, and testes; activity of the plasma alkaline phosphatase), and apparent absorption of zinc, iron, copper, and manganese remained unchanged by the different dietary treatments. The apparent phosphorus absorption was highest in the phytase group. PA decreased and microbial phytase improved the apparent absorption of calcium and magnesium. Liver cadmium concentration, total liver and kidney cadmium content, as well as fractional liver and kidney cadmium accumulation in rats fed the diet containing PA were significantly higher than those in the controls. Phytase supplementation lowered liver and kidney cadmium accumulation. Differences in calcium and magnesium bioavailability due to PA and microbial phytase may be one factor in the alteration of tissue cadmium accumulation.

Cadmium accumulation in the mummichog, Fundulus heteroclitus, adapted to various salinities.

It is commonly known that salinity affects the toxicity of cadmium to aquatic biota. This toxicity has been shown to decrease with salinity in a variety of estuarine organisms. The effect of salinity on cadmium toxicity may be primarily due to greater complexation of free cadmium ions by chloride ions with increasing salinity. A high concentration of cadmium is found in the liver, kidney, intestine, and gills of fish after cadmium exposure. The kidney, intestine, and gills are important organs for osmotic regulation of fish and each function of these organics is altered by salinity of the medium in which fish live. This alteration in the kidney, intestine, and gills may influence cadmium accumulation. This study was conducted to examine cadmium accumulation in tissues of mummichog, Fundulus heteroclitus, adapted to various salinities and to evaluate the effects of salinity on cadmium accumulation from a physiological viewpoint. 13 refs., 2 tabs.

In vivo magnetic resonance imaging of the blue crab, Callinectes sapidus: Effect of cadmium accumulation in tissues on proton relaxation properties

Nuclear magnetic resonance imaging (MRI) has been used to visualize the internal anatomy of a living blue crab. The resolution obtained in these studies was sufficient to distinguish individual organs by the differences in their proton densities and proton relaxation properties. T1 (spin-lattice relaxation time)-weighted imaging revealed the lipid-rich nature of the hepatopancreas and gonadal tissue. To evaluate the effect of metal-induced stress on the different organs, crabs were exposed to elevated levels of cadmium in their diet, which resulted in increased concentrations of both cadmium and copper in the hepatopancreas. The spin-spin relaxation time, T2, of mobile protons in the metal-exposed tissue was significantly greater than T2 in the control tissues. These measurements suggest that the excess copper in the exposed tissues was diamagnetic [Cu(I)], since the presence of paramagnetic copper [Cu(II)] would result in a decrease of observed T2 values. We hypothesize that the increased T2 value is a reflection of increased free water in the hepatopancreas. These studies show that magnetic resonance imaging is an important nondestructive tool for the study of morphological and physiological changes that occur in marine invertebrates in response to anthropogenic and natural stresses.

Comparison of Cadmium Accumulation in Tissues between Carp Cyprinus carpio and Red Sea Bream Pagrus major.

Carp and red sea bream were exposed for 96h to 0.3mgCd/l in freshwater and 10mgCd/l in seawater, respectively. The cadmium tissue distributions and cadmium cytosolic partitioning in tissues were analyzed using Sephadex G-75 chromatography to estimate the toxicity in tissues. Cadmium tissue distributions in carp and red sea bream after intraperitoneal administrations of CdCl2 and cadmium-metallothionein (CdMT) were also investigated to compare the cadmium movement in their bodies. The exposure of carp to cadmium resulted in the highest accumulation in the gills, followed in descending order by the kidney, intestine, and hepatopancreas. The highest proportion of cadmium concentration in the HMW pool (fractions containing enzymes) relative to the MMW pool (fractions containing metallothionein) was found in the gills. These results suggest that the gills of carp are most likely to be harmfully affected by exposure to an acute level of cadmium. The exposure of red sea bream to cadmium resulted in the highest accumlation in the liver, followed in descending order by the kidney, intestine, and gills. The cadmium concentration in the HMW pool was highest in the kidney. However, the highest proportion of cadmium concentration in the HMW pool relative to the MMW pool was found in the intestine. These results suggest that the maximum detoxification capacity was reached first in the intestine. After the intraperitoneal administration of CdMT, a significantly high accumulation of cadmium was found in the kidney of carp but not in the kidney of red sea bream. This result suggests that the ability to trap the cadmium bound to MT in plasma by kidney may be lower in red sea bream than in carp. In conclusion, the osmotic regulation mechanisms in fish may possibly be related to the distribution and movement of cadmium in the body.

Cigarette smoking and the pathogenesis of atherosclerosis--a hypothesis.

Cigarette smoking is associated with the accumulation of cadmium in tissues. Ascorbic acid can detoxify the accumulated cadmium in the tissues. The low tissue ascorbic acid concentrations found in cigarette smokers are due to the need for the vitamin to detoxify the accumulated cadmium associated with cigarette smoking. The low tissue ascorbic acid concentration predisposes to lipidaemia and to the upset of the ground substances in the intima of blood vessels. This sequence of events leads to the pathogenesis of atherosclerosis from cigarette smoking. Therefore cigarette smoking is not a separate factor in the pathogenesis of atherosclerosis but acts by increasing the second of the two major factors, hypertension and a raised serum cholesterol.