Stanley M. Shaw

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.

Cadmium fetotoxicity in rats following prenatal exposure

Timed pregnant Holtzman rats were received on day 3 of gestation, weighed, and housed in individual stainless steel cages. Tap water and food pellets were allowed ad libitum. The maternal weight gain was monitored throughout the gestationeal period. A single intraperitoneal injection of 1.0 or 2.0 mg/kg of cadmium, as cadmium acetate, was administered to pregnant rats on day 12, 14, 18, or 20 of gestation. Control rats received saline solution. Maternal rats receiving cadmium on day 12 or 14 of gestation (Groups I and II) were sacrificed 2 days later. The majority of maternal rats receiving cadmium on day 18 or 20 (Groups III and IV) were sacrificed on day 21 of gestation while a limited number of Group III and IV maternal animals were allowed parturition on day 21 of gestation and viable neonates sacrificed 2 days later and examined.

Placental Transfer and Teratology of Pentachlorophenol in Rats

Pentachloro[U-14C]phenol was administered orally to Charles River CD strain pregnant rats on day 15 of gestation. Concentrations found in the placentas and fetuses up to 32 hr remained very small indicating that the amount that passes through the placental barrier is negligible. Unlabeled compound was administered on days 8, 9, 10, 11, 12, and 13 of gestation. The incidence of resorptions in the treated animals was not significantly greater than that in the controls. Although malformations were observed, the number was minimal and could have been due to the toxic effects of the compound on the maternal rat.

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 effect of diagnostic-quality X-irradiation on the developing postnatal rat retina.

Abstract The morphological effect of diagnostic-quality X-rays (140 kVp, 2·35 mm Al h.v.l.) on the developing postnatal rat retina was studied by the use of light and electron microscopy. Different litters of postnatal rats were exposed to 100 rontgens (R) of X-rays on each of the first seven days of life (day 0 through day 6, day 0 being the day of birth). Examination with light and electron microscopy on day 8 and day 14 revealed that the postnatal retina was insensitive to the induction of permanent retinal injury at the 100 R exposure level. No visible abnormalities that could be attributed to the effect of the irradiation were demonstrated in any of the retinal layers. Animals exposed on postnatal day 3 or day 4 to 200, 300, or 500 R of diagnostic-quality X-rays demonstrated severe injury within the outer layers of the sensory retina. The types of developmental lesions observed included (1) generalized dysplasia of the outer nuclear layer, (2) clusters of aberrant receptor cells within the photoreceptic inner and outer segments, (3) foci of apparent agenesis of the inner and outer segments and of the outer plexiform layer, and (4) the presence of an extra fiber layer within the inner nuclear layer. It was concluded that a threshold exposure exists for diagnostic-quality X-rays which is between 100 and 200 R, and that the rat retina is considerably more radiosensitive on postnatal day 3 than on postnatal day 4.

The biodistribution of [75Se]bis[β-(N,N,N-trimethylamino)ethyl]selenide diiodide in adult guinea pigs

The biodistribution of [75Se]BISTAES was studied in guinea pigs. A higher concentration of radioactivity was observed in articular cartilage than in other tissues or organs. A minimal amount of radioactivity was found in the blood, muscle and bone. The compound was excreted rapidly in urine. The target to background ratios were encouraging. [75Se]BISTAES has potential as an articular cartilage imaging agent and further studies in osteoarthritic animals are merited.

Influence of complex charge and size on the uptake of 99mTc-diphosphonates in osteogenic tissue

The biodistributions of six chromatographically pure 99mTc-HEDP complexes have been determined in soft tissues, normal bone and osteogenic lesions (induced with a Walker 256 tumor) in Fisher 344 rats. The physical properties of each 99mTc-HEDP complex including anionic charge, partial molar volume, molecular weight and spectral characteristics are known; thus allowing structure-activity relationships to be drawn. The results indicate that the smallest, low charged, mononuclear 99mTc-HEDP complexes have the greatest uptake in bone lesions, and the highest lesion to muscle and lesion to normal bone ratios.

A 4π liquid-scintillation whole-body counter—I. Design, operating characteristics, and calibration☆

Abstract A 4π large volume liquid-scintillation counter composed of two 2π detector tanks is described. This counter is used primarily for measuring 40 K activity in human beings and large animals.

The Effect of Formulation on 1–131 Dissolution In Vitro from Sodium Iodide Capsules

AbstractBecause of the importance of the bioavailability of 1–131 for thyroid uptake studies and thyroid therapy, the present investigation was conducted to determine the influence of diluents, type of lubricant and the concentration of lubricant on the in vitro release rate of 1–131 from 1–131 sodium iodide capsules. Formulations and 1–131 sodium iodide capsules were prepared in-house and dissolution profiles determined using the U.S.P. XXII Dissolution Test. Distilled water was employed as the solvent. Lactose only, calcium phosphate only, a mixture of dicalcium phosphate—Avicel PH 101 and a sodium phosphate formulation consisting of lactose, L-cysteine hydrochloride and sodium phosphate were chosen as diluents. Several concentrations of the lubricant magnesium stearate were employed. The influence of 3% or 5% talc as the lubricant was studied using the sodium phosphate formulation.The results of the study demonstrated the influence of the formulation on the dissolution of 1–131 when the concentration o...

Determination of dissolution profiles for several commercially available therapeutic [131I]sodium iodide capsules

The dissolution profiles for [131I]sodium iodide therapeutic capsules from three commercial vendors were studied. The 131I release rate in water was rapid for the capsules with 100% release attained within 35 min. There was no significant difference in dissolution profiles for the capsules from the three vendors.