Stephen J Hayward

Learn More
A group of 80 menstruating rhesus (Macaca mulatta) monkeys were randomly allocated to four similar test rooms (20 monkeys/room) and then randomly allocated within each room to one of five dose groups (four females/dose group/room). Each day, the monkeys self-ingested capsules containing doses of 0, 5, 20, 40 or 80 micrograms Aroclor 1254/kg body weight.(More)
The immunomodulatory effects of low-level, chronic polychlorinated biphenyl PCB; (Aroclor 1254) exposure were investigated in female rhesus (Macaca mulatta) monkeys. Five groups of monkeys (initially 16 monkeys/group) were orally administered PCB at levels of 0, 5, 20, 40 or 80 micrograms/kg body wt/day. Tests for immunomodulation were initiated after 55(More)
The effects of PCB (Aroclor 1254) on the immune system of adult female rhesus monkeys were investigated in a chronic study wherein five groups of monkeys (16/group) were administered (orally) PCB at levels of 0.0, 5.0, 20.0, 40.0 or 80.0 micrograms/kg body wt daily. Tests for immunotoxicity were initiated at 23 months of exposure to PCB, at which time the(More)
Previous studies have shown that canola oil (CA), compared with soybean oil (SO), shortens the life span of stroke-prone spontaneously hypertensive (SHRSP) rats, a widely used model for hemorrhagic stroke. SHRSP rats are highly sensitive to dietary cholesterol manipulations because a deficiency of membrane cholesterol makes their cell membranes weak and(More)
The free amino acid profile and sugar (fructose, glucose, and sucrose) composition were determined in potato samples selected to give a large range of variation (a total of 66 samples). From these samples French fries were produced in a laboratory-scale simulation of an industrial process followed by a finish fry at 180 degrees C for 3.5 min using a(More)
In order to manage risk of ochratoxin A (OTA) in foods, we re-evaluated the tolerable daily intake (TDI), derived the negligible cancer risk intake (NCRI), and conducted a probabilistic risk assessment. A new approach was developed to derive 'usual' probabilistic exposure in the presence of highly variable occurrence data, such as encountered with low(More)
A 2 year feeding study was conducted with male and female B6C3F1 mice that consumed diets containing 0, 1, 5, or 10 ppm deoxynivalenol (DON). Survivability was good and, while the test animals gained less weight with increasing levels of DON in the diet, there were no consistent toxic manifestations associated with DON consumption. There was some evidence(More)
A group of 80 menstruating rhesus (Macaca mulatta) monkeys were randomly allocated to four similar rooms (20 monkeys/room) and then to one of five dose groups (four females/dose group/room). Each day the monkeys self-ingested capsules containing doses of 0, 5, 20, 40 or 80 microg Aroclor 1254/kg body weight. After 25 months of continuous dosing,(More)
Blood plasma samples collected from 144 healthy volunteers in 16 locations across Canada in 1994 were analysed for ochratoxin A (OTA). The method of analysis included cleanup by C18 solid phase extraction and immunoaffinity columns followed by liquid chromatography (LC) with fluorescence detection, which gave 86.5% (s.d. = 9.7) recovery (n = 31) of OTA(More)
Experiments were performed to determine the thermal resistance of hepatitis A virus (HAV) in three types of dairy products containing increased amounts of fat content (skim milk, homogenized milk; 3.5% MFG, and table cream; 18% MFG). HAV-inoculated dairy products were introduced into custom-made U-shaped microcapillary tubes that in turn were simultaneously(More)