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Biomedical subjects

W K Porter

Publications and source records attributed to W K Porter.

6 recordsLinked to original sources

Mechanical model testing of rebreathing potential in infant bedding materials.

Rebreathing of expired air may be a lethal hazard for prone sleeping infants. This paper describes a mechanical model to simulate infant breathing, and examines the effects of bedding on exhaled air retention. Under simulated rebreathing conditions, the model allows the monitoring of raised carbon dioxide (CO2) inside an artificial lung-trachea system. Resulting levels of CO2 (although probably exaggerated in the mechanical model compared with an infant, due to the model's fixed breathing rate and volume) suggest that common bedding materials vary widely in inherent rebreathing potential. In face down tests, maximum airway CO2 ranged from less than 5% on sheets and waterproof mattresses to over 25% on sheepskins, bean bag cushions, and some pillows and comforters. Concentrations of CO2 decreased with increasing head angle of the doll, away from the face down position. Recreations of 29 infant death scenes also showed large CO2 increases on some bedding materials, suggesting these infants could have died while rebreathing.

Bedding and Linens↗

Potential biological hazards of commercially available cleansers for dentures.

Thirteen representative denture cleansers were selected from among more than 32 retail products to be tested for potential hazard and toxicity to humans. Products were subjected to toxicological analyses by using the biological tests (acute oral toxicity in rats, eye and skin irritation in rabbits) specified in the Federal Hazardous Substances Act Regulations. All products were eye irritants with ranges from slight to severe. Three produced a primary skin irritation response (one was corrosive), while five of the denture cleansers produced oral LD50 values below 5 g/kg. Furthermore, a provisional upper gastrointestinal irritancy test used in rabbits indicated that eight of the denture cleansers produced upper gastrointestinal irritation, which was, in general, dose-related.

Animals↗

Detergent toxicity survey.

A survey of over 249 detergent products involving biological testing, chemical analyses, and product label reviews has been conducted from 1971-1976 for determining compliance with the Federal Hazardous Substances Act. Test results for 145 detergent products having both chemical and biological data were examined. All of the tested detergents were rabbit eye irritants. Forty-seven per cent were also either rabbit primary skin irritants or corrosives. Eighty-one per cent were either rabbit esophageal test irritants or corrosives, and 80 per cent had rat oral toxicities 5g/kg or less.

Animals↗

Percutaneous absorption of radiolabeled TRIS from flame-retarded fabric.

Surface tris-(2,3-dibromopropyl) phosphate (TRIS) was removed from flame-retarded polyester fabric by benzene-hexane extraction and replaced with 14C-TRIS. Sections of the radiolabeled fabric (10 X 12 cm) were placed in contact with the clipped skins of rabbits, and urine and feces were collected over a 96 hr period. The cloths were allowed to remain dry or were moistened with either urine or simulated sweat. A similar collection of urine and feces was performed following i.v. injection of 14C-TRIS. From the results of these experiments, it can be calculated that up to 17 percent of the radiolabel on the cloth penetrated rabbit skin over the 96 hr period of exposure. Most of the excreted radiolabel appeared in the urine, with the kidney being the organ of highest specific radioactivity. The highest absorption of radiolabel occurred in the urine-moistened cloth group. Moistening the cloth with simulated sweat produced no increase in absorption over that seen with dry cloth.

Animals↗