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Biomedical subjects

C J Johnson

Publications and source records attributed to C J Johnson.

106 records · Page 6Linked to original sources
PubMed1975

Carbon monoxide in school buses.

Following an incident in which eight children became ill from carbon monoxide in a school bus, an investigation was made of CO levels in school buses in the Seattle area. The procedure selected for the evaluation was to test a large number of buses at a nearby ski resort. On the day selected for the sampling, over 200 buses arrived, bringing school children from a number of school districts in the Seattle are for skiing lessons. As they arrived, 33 buses were checked immediately to determine in-transit levels of CO. Four of the 33 buses had CO levels in excess of Environmental Protection Agency maximum allowable concentrations for an 8-hr exposure. As the buses sat idling in the parking lot, 65 of them were tested--during the lunch hour when the students returned to the buses to have their lunch and to rest. Two buses had nearly 3 times the concentration of CO permitted by the EPA for a 1-hr exposure. A total of seven buses (10 per cent) had concentrations of CO not permitted by the EPA for more than a 1-hr period. Altogether there were 24 buses (36 per cent) that had levels of CO in excess of EPA standards for an 8-hr exposure. As a result of these determinations and other observations a number of recommendations were made to reduce the hazard of exposure to carbon monoxide in school buses.

Air Pollutants↗
PubMedDate not supplied

Visualization of fibrillar amyloid deposits in living, transgenic Caenorhabditis elegans animals using the sensitive amyloid dye, X-34.

Transgenic Caenorhabditis elegans animals can be engineered to express high levels of the human beta amyloid peptide (Abeta). Histochemistry of fixed tissue from these animals reveals deposits reactive with the amyloid-specific dyes Congo Red and thioflavin S (Fay et al., J. Neurochem 71:1616, 1998). Here we show by immuno-electron microscopy that these animals contain intracellular immunoreactive deposits with classic amyloid fibrillar ultrastructure. These deposits can be visualized in living animals using the newly developed, intensively fluorescent, amyloid-specific dye X-34. This in vivo staining allows monitoring of amyloid deposition in individual animals over time. The specificity of this staining is demonstrated by examining transgenic animals expressing high levels of a non-fibrillar beta peptide variant, the beta single-chain dimer. These animals have deposits immunoreactive with anti-beta antibodies, but do not have X-34 deposits or deposits with a fibrillar ultrastructure. X-34 can also be used in vivo to visualize putative amyloid deposits resulting from accumulation of human transthyretin, another amyloidic protein. In vivo amyloid staining with X-34 may be a useful tool for monitoring anti-amyloidic treatments in real time or screening for genetic alterations that affect amyloid formation.

Alkenes↗
PubMedDate not supplied

Incidence of hospitalized injuries among pregnant women in Maryland, 1979-1990.

INTRODUCTION: Injuries are a leading cause of morbidity among pregnant women. We compared injuries among pregnant women and all women of reproductive age in a large defined population. METHODS: Maryland hospital discharge data files from 1979-1990 were used to identify injuries in pregnant women and in all women 15-44 years of age. Injured pregnant women were defined as those hospitalized with concurrent ICD-9-CM discharge codes for injury and pregnancy. RESULTS: The 80,311 hospitalizations with injury of women 15-44 years old included 2,185 hospitalizations of pregnant women. The incidence of hospitalized injury per 100,000 person-years was 460 for pregnant women and 608 for all women 15-44 years old. Median length of stay and cost per hospitalization were 3.0 days and $1,478 for pregnant women and 4.0 days and $1,666 for all women 15-44 years old. Leading causes of hospitalized injury in pregnant women were poisonings (16.9%), fractures (14.7%), sprains (10.9%), and contusions (8.0%). Compared to all women 15-44 years of age, pregnant women had significantly fewer hospitalizations for dislocations, fractures, poisoning, sprains, and intracranial injuries, and more hospitalizations for contusions and internal injuries. Based on limited information about external causes of injury, pregnant women had significantly fewer hospitalizations for poisoning, drowning/suffocation, and suicide attempts than all women 15-44 years of age. CONCLUSIONS: Many hospitalizations of pregnant women are for relatively minor injuries requiring a short duration of stay, possibly to gauge the impact of the injury on the mother and the fetus. Since most pregnant women receive at least some medical care during pregnancy, prenatal visits represent an ideal time to implement strategies to prevent injuries.

Accidents↗