Thomas N Black

Learn More
Since the mid 1940s, fluoride has been added to tap water in American communities in an effort to reduce the incidence of dental caries in the population. When the levels of fluoride in drinking water were tested and set, water was the only measurable source of fluoride for most communities. Now, adults and children ingest fluoride with foods and beverages(More)
Deoxynivalenol (DON, vomitoxin), is one of the most common contaminants of cereal grains world-wide. The effects of DON on fetal development were assessed in Charles River Sprague-Dawley rats. Pregnant female rats were gavaged once daily with DON at doses of 0, 0.5, 1, 2.5, or 5 mg/kg body weight on gestation days (GD) 6-19. At cesarean section on GD 20,(More)
The potential of sodium fluoride (NaF) to affect spermatogenesis and endocrine function was assessed in P and F1 generation male rats. Male and female experimental rats received sodium fluoride in their drinking water at one of four concentrations (25, 100, 175, 250 ppm). P generation male and female rats were exposed to sodium fluoride in their drinking(More)
Despite the chronic exposure of the US population to fluoridated drinking water since the 1940s, existing studies have been judged inadequate to determine any potential reproductive or developmental hazard. This study was conducted to determine the effects of sodium fluoride (NaF) on foetal development. Sperm-positive female rats were given 0, 10, 25, 100,(More)
The effects of moderate increases in dietary calcium on maternal and foetal mineral interactions were studied in Charles River CD/VAF Plus rats. Female rats were given 0.50, 0.75, 1.00 or 1.25% dietary calcium as calcium carbonate in AIN-76A diets for 6 wk before mating, during mating and for 20 days of gestation. Inductively coupled argon plasma-atomic(More)
This study provides quantitative information on the effect of sodium fluoride (NaF) on the testes of F1 generation male rats exposed in utero and during lactation to NaF at one of four concentrations (25, 100, 175, 250 ppm). At weaning, the F1 generation males were exposed to NaF in their drinking water for 14 weeks, after which time testicular tissues were(More)
Sodium fluoride (NaF) has been used to fluoridate drinking water in the United States since the mid 1940s. Because of the lack of reliable studies on the multigeneration effects of the compound, NaF (0, 25, 100, 175 or 250 ppm in drinking water) was given to rats continuously during three generations. Parental (F0) generation rats were treated for 10 weeks(More)
The anatomy of the reproductive tract of the male sand rat, Psammomys obesus, was examined by light microscopy. Histologically, the reproductive tract is similar to other rodent species. Seminiferous tubules in the 1-month-old sand rat do not contain a tubular lumen but Sertoli cells, spermatogonia and spermatocytes are present. A full complement of germ(More)
Mutants of Anabaena sp. strain PCC 7120 that are incapable of sustained growth with air as the sole source of nitrogen were generated by using Tn5-derived transposons. Nitrogenase was expressed only in mutants that showed obvious morphological signs of heterocyst differentiation. Even under rigorously anaerobic conditions, nitrogenase was not synthesized in(More)
Male and female Sprague-Dawley (Spartan) rats were fed dietary levels of 0, 0.25, 0.50, 0.75 or 1.00% triphenyl phosphate (TPP) from 4 weeks post weaning for 91 days, through mating and gestation. At these dietary levels, the daily intake of TPP during pregnancy was 0, 166, 341, 516 and 690 mg/kg body weight, respectively. TPP exposure had no toxic effects(More)