Richard L. Tyndall

Effects of butylated hydroxytoluene alone or with diethylnitrosamine in mice

Abstract Mice (18 months old) given butylated hydroxytoluene (BHT) at a dietary level of 0·75% for 16 months had 63·6% of lung tumours compared with 24·0% in controls. Mice given dietary BHT as well as diethylnitrosamine (DENA) in the drinking-water (average total intake 330 mg DENA/kg) had more lung tumours per mouse (4·0) than did the controls or those given DENA alone or BHT alone (1·4–2·2). The incidence of reticulum-cell sarcomas in mice killed at 12 months of age in the group treated with BHT plus DENA exceeded control values (52·6 and 22·7%, respectively), while the incidence in groups receiving DENA alone or BHT alone was not significantly different from that in controls. At 18 months, the incidence of reticulum-cell sarcoma in both groups given BHT was significantly less than in the groups not receiving BHT. At 18 months of age, a higher percentage of squamous-cell carcinomas was seen in the forestomach of mice given BHT plus DENA than in mice receiving DENA alone. The production of cysts within the liver parenchyma after DENA treatment also appeared to be potentiated by BHT treatment.

Quantitation of Free-Living Amoebae and Bacterial Populations in Eyewash Stations Relative to Flushing Frequency

This study investigated the concentration of amoebic and bacterial populations in eyewash station water relative to various flushing regimens. Amoebae concentrations averaged approximately 200 amoebae/100 mL in 13 of 15 stations positive for amoebae and consisted of Hartmannella and Acanthamoeba. Bacterial concentrations ranged from 10(0) to more than 10(5) colony forming units per mL. Amoebic concentrations differed notably between stations located in Buildings X and Y (p < 0.0001). Further study indicated that removal of diffusing screens did not substantially change (p > 0.05) the concentration of amoeba. Amoebic and bacterial concentrations temporarily decreased with the various flushing regimens tested. Lower amoebic concentrations were not sustained by a weekly 3-minute or a monthly 1-minute flushing regimen. However, weekly 3-minute flushes appeared to be more effective in maintaining lowered bacterial concentrations (p < 0.0001).

Isolation of a newLegionella species from thermally altered waters

Legionella-like bacteria were isolated from thermally altered water in Pennsylvania and Minnesota. These organisms were isolated from tissues of infected guinea pigs after intraperitoneal inoculation of water concentrates. While the cultural and morphological characteristics indicated the isolates wereLegionella, they did not react with antibodies prepared against known species of the genus. Antisera prepared against one of the isolates reacted maximally with the other ten isolates. Fluorescent antibody analysis of water concentrates from geographically disparate sites indicated that the environmental distribution is broad and that concentrations of the Oak Ridge strain ofLegionella were similar to those of serogroups 1, 2, 3, and 4 ofLegionella pneumophila.

Qualitative alterations in plasma esterases in BALB/c mice following the administration of diethylnitrosamine☆

Selected non-specific plasma esterases in female BALB/c mice, separated by polyacrylamide gel electrophoresis, were qualitatively altered following treatment of the mice with diethylnitrosamine (DEN). These alterations include a decreased preference for naphthyl butyrate as a substrate relative to naphthyl acetate; decreased sensitivity to enhancement by divalent cations such as Ca2+, Mg2+, and Mn2; and an increased sensitivity to inhibition by eserine. All esterase species affected were also quantitatively altered and some were testosterone-dependent.