Richard J. Vetter

Fetal effects of cadmium in pregnant rats on normal and zinc deficient diets

SummaryThis investigation has shown that not only the extent of fetal resorption and malformation but also the types of malformation seen in rats depend upon the strain used and day of gestation. Furthermore, the effects of zinc deficiency and cadmium administration on the fetus can be at least additive, as was seen for malformations. For fetal resorption, zinc deficiency potentiated the action of cadmium.

The use of the three-ridge clam (Amblema perplicata) to monitor trace metal contamination

The three-ridge clamAmblema perplicata was used to monitor two streams for the presence of zinc (Zn) and cadmium (Cd) derived from an industrial source. Clams were collected from a relatively uncontaminated area in one river and transported to four study sites in the two contaminated streams. The clams were placed into polyethylene cages and left in these streams for one week. Control clams were treated in a similar manner and left in the uncontaminated river.The highest mean concentration of Zn (956 µg/g dry wt) was found in the gill tissue of clams from the most contaminated site. The highest mean Cd concentration (18.6 µg/ g dry wt) was found in digestive glands of clams, also from the most contaminated site. Mean concentrations at contaminated sites were significantly higher than background and control levels; the findings suggest that these particular organs of clams may be useful in monitoring levels of Zn and Cd in other freshwater systems.

The impact of an industrially contaminated lake on heavy metal levels in its effluent stream

Levels of cadmium and zinc in various components of Williamson Ditch (an industrially contaminated stream flowing into Palestine Lake), Trimble Creek (a stream draining Palestine Lake) and the Tippecance River (a river receiving Trimble Creek) were determined. Water, sediment, plant, fish and clam samples were analyzed for cadmium and zinc content by atomic absorption spectrophotometry. Unweighted mean metal concentrations in Trimble Creek were the following: water, 51 µg Zn/1 and 4.2 µg Cd/1; sediment, 592 µg Zn/g and 48.8,µg Cd/g; plants, 375 µm Zn/g and 7.91 µg Cd/g; fish, 145 µg Zn/g and 6.02 µg Cd/g. These concentrations were generally lower than those found in Williamson Ditch and higher than those found in the Tippecanoe River or background levels previously reported for other aquatic ecosystems.

The maternal distribution and placental transfer of cadmium in zinc deficient rats.

SummaryAlthough a transitory maternal zinc deficiency has been shown to result in an increased cadmium-induced fetotoxicity, the results of the present investigation indicated that a maternal zinc deficiency apparently did not affect the placental transfer of cadmium. However, a zinc deficiency did alter the maternal distribution of cadmium. The increased cadmium fetotoxicity associated with a maternal zinc deficiency may be caused by a maternal alteration rather than a direct effect on the fetus. Further study is necessary prior to any definitive statement concerning the effects of a maternal zinc deficiency on cadmium. fetotoxicity.

The uptake of Manganese-54 by green algae (Protococcoidal chlorella), Daphnia magna, and fathead minnows (Pimephales promelas)

Concentration factors (CF) of 54Mn for three aquatic species: green algae (Protococcoidal chlorella), Daphnia magna, and fathead minnows (Pimephales promelas) were determined following direct exposure to the isotope in solution. The maximum accumulation (CF = 911) in P. chlorella was reached at 48 hours of exposure; the maximum uptake (CF = 65) in Daphnia was reached at 8 hours of exposure; and the maximum accumulation (CF = 22.6) in fathead minnows was at 128 hours of exposure. The data indicate that 54Mn accumulation decreases with ascent up a theoretical aquatic food chain when water is the only source of contamination.

Manganese-54 accumulation by Chlorella spp., Daphnia magna and yellow perch (Perca flavescens)

Concentration factor and biological half-life of 54Mn were determined in three species representing an ecologically and economically important food chain. Green algae (Chlorella spp.), Daphnia magna and yellow perch (Perca flavescens) were exposed to 54Mn in water and assayed for 54Mn uptake. Steady state concentration factors computed from the laboratory data for algae, Daphnia and perch were 4230, 17 000 and 11, respectively. Respective biological half-lives were 1.6, 1.2 and 8.3 days.

Simple methods for determining the accuracy of tumor blood flow measurements using radioactive microspheres in rats

Two simple methods are presented which allow positive identification of the accuracy and precision of the microsphere technique and a quick verification of sphere entrapment in tumor vessels. A known flow of Ringers solution from a motor-driven syringe is perfused through the rats isolated systemic circulation from left ventricle to right atrium and collected in a funnel. Using this preparation, total blood flow in rats measured with radioactive microspheres injected into the left ventricle was 97% of actual flow. The coefficient of variation (standard deviation/mean) of the microsphere measurements was 0.22. In the same preparation, nonentrapment of microspheres in subcutaneous tumor nodules grown on a hind limb could be measured from the difference in counts collected in venous effluent before and after placement of a tourniquet proximal to the tumor. For example, in two types of transplantable carcinoma, we found nonentrapment of less than 0.1% of the injected microspheres. Such a shunt would correspond to less than 10% of microspheres entering a typical tumor nodule and, in turn, less than 10% underestimation of true flow to the tumor. These two techniques may be helpful to other investigators in testing the accuracy of microsphere methods in various small animal tumor models.

Thermoluminescence and microwave induced thermoluminescence fading of rare-earth-doped barium titanate ceramics

Abstract The effect of microwave exposure on thermoluminescence (TL) of rare-earth-Uoped BaTiO3 ceramic phosphors was investigated as a method for microwave dosimetry. Following exposure to 60Co gamma radiation, phosphors exhibited a TL glow curve with two peaks. The low temperature glow peak faded rapidly, but the high temperature glow peak was relatively stable with more than 50% of the initial response remaining after 48 h. The phosphors were linear in TL response over an exposure range of 103 to 105 R. Within-batch variation in TL response was insignificant for all phosphors except BaTiO3 :Ce. Readouts from three batches of BaTiO3) :Dy showed reproducible glow curve structure but significant differences in glow curve area. All phosphors except BaTiO3, :Nd showed statistically significant TL fading following exposure to 100 mW/cm2 or more of microwaves. Fading increased with increasing microwave power density. Results of these studies show that rare-earth-doped BaTiO3 ceramics can potentially be utiliz...

Temperature Distributions Induced by 2450 MHz Microwave Radiation in a Trilayered Spherical Phantom

ABSTRACTThe properties of phantom modeling materials used in the fabrication of a trilayered spherical phantom and the characteristics of heating patterns induced in the phantom by 2450 MHz microwave radiation are discussed. The techniques used in the preparation of the simulated fat, muscle and brain materials resulted in material mixtures with homogeneous, reproducible and stable dielectric properties. The dielectric properties of these simulated materials exhibited no temperature dependence from 20° to 50°C. The heating patterns in the trilayered spherical phantom were obtained using an inexpensive liquid crystal photographic technique. The characteristics of these heating patterns are shown to be in good qualitative agreement with heating patterns obtained by thermographic techniques and theoretical calculations in homogeneous spherical phantoms. Heating patterns recorded in a bilayered spherical phantom by liquid crystal techniques have a shape and location similar to heating patterns observed in the...

Effect of altered thyroid states on liver and kidney uptake of 109Cd in rats

Abstract Hypothyroid and hyperthyroid states were induced in rats by drug treatment with propylthiouracil and thyroxine, respectively. The thyroid states were verified by measuring serum thyroxine using a commercial competitive protein-binding technique. A single 109 Cd ip injection was then given to three groups: hypo-, eu-, and hyperthyroid. The uptake of 109 Cd in liver and kidneys was measured at times ranging from 1 to 120 hr. On a per gram basis, 109 Cd uptake in livers and kidneys of hypothyroid rats was significantly greater than that of eu- and hyperthyroid rats, even though there was a dwarfing effect in the hypothyroid group. The transfer of 109 Cd from the liver to the kidneys was not affected by the altered thyroid states.