Biomedical subjects

D C Johnson

Publications and source records attributed to D C Johnson.

327 records · Page 19Linked to original sources

PubMedDate not supplied

Epidemiologic studies of the 1975 avian influenza outbreak in chickens in Alabama.

The epidemiology of the first reported non-fowl-plague avian influenza (AI) virus, A/Chicken/Alabama/75 (Hav4Neq2), isolated from chickens in the United States is discussed. The signs and pathologic changes have been described. The environment, nutrition, and stress factors are discussed as possible contributors to the disease syndrome observed in 3 commercial egg-laying flocks. Avian influenza antibody was demonstrated by agargel precipitation in convalescent chickens through 83 days postinfection. A serological survey of 321 additional poultry flocks was negative for antibodies against avian influenza. A survey was made by serology and virus isolation techniques on 387 wild free-flying birds that fed and roosted in the area. Wild waterfowl are discussed as a possible source of the AI virus.

Alabama↗

PubMedDate not supplied

The evolution of gait in childhood and adolescent cerebral palsy.

A longitudinal study over a mean of 32 months was conducted on 18 subjects with spastic diplegia, ranging in age from 4 to 14 years. Three-dimensional gait analyses were performed to compare the temporal and kinematic data across the two time intervals. The comparison revealed a deterioration of gait stability evidenced by increases in double support and decreases in single support with time and growth (p < 0.05). Kinematic analysis revealed a loss of excursion about the knee, ankle, and pelvis (p < 0.05). Additionally, passive range-of-motion analysis revealed a decrease in the popliteal angle over time (p < 0.05). In conclusion, this longitudinal investigation revealed that, in contrast to the gait of children with intact motor function, ambulatory ability tends to worsen over time in spastic cerebral palsy. Insight into the natural progression of gait function in cerebral palsy is essential when evaluating the change in motor status over time or the effects of an intervention in this population.

Adolescent↗

PubMedDate not supplied

An occurrence of avian influenza virus infection in laying chickens.

The isolation of avian influenza virus from chickens is reported for the first time in the United States since the fowl plague outbreak of 1929. The type-A virus was isolated from commercial Leghorn laying hens between 54 and 55 weeks old and involved three different farms in north-central Alabama. These flocks experienced up to 69% mortality and a severe decrease in egg production within a 14-day period.

Alabama↗