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Biomedical subjects

A R Barr

Publications and source records attributed to A R Barr.

At least 37 records · Page 2Linked to original sources
PubMed1990

Fractures of the accessory carpal bone in the horse.

The clinical signs and radiographic appearance of 19 cases of fracture of the accessory carpal bone of horses are described. In 17 cases the fractures were in the frontal plane and occurred palmar to the groove on the lateral aspect of the bone. In six cases radiographs taken six months to three years after the fracture occurred showed no evidence of bony union; nevertheless, these and five other horses for which follow-up information was available for up to seven years all became sound, and seven of them returned to competitive activity.

Animals↗
PubMed1990

Colonization of Anopheles occidentalis and Anopheles hermsi.

The colonization of Anopheles occidentalis is described and contrasted with colonization of a related species, An. hermsi. The latter species formerly was considered to be conspecific with the former, but the 2 species differ considerably in biological characteristics.

Animals↗
PubMed1990

Microsporidian infection of Culex peus.

Larvae of Culex peus were collected from a small, grassy, muddy pond. Two of these larvae showed external symptoms related to microsporidian infection, such as swollen appearance and porcelain-like color. This spore is similar to Amblyospora californica from Cx. tarsalis in morphology and in development, and like Am. californica, is not infective to uninfected larvae. This suggested that it was a species belonging to the genus Amblyospora. It is, however, apparently a different species since its size is significantly smaller than that of Am. californica, although these two species sometimes occur in the same breeding sites. Larvae were never infected when they were fed with spores from lethally infected larvae or from water of the breeding site. This indicates that the microsporidian could not complete its developmental cycle in the mosquito host. Whether or not they need an alternate host, such as copepod which have been found to serve as an intermediate hosts for several other species of Amblyospora, remains to be worked out.

Animals↗
PubMed1989

Three cases of non-displaced radial fracture in horses.

Three horses with non-displaced fractures of the radius were examined. The affected animals showed a sudden onset of severe forelimb lameness with swelling of the antebrachium. Two cases had associated wounds on the medial aspect of the distal radius. The diagnoses were confirmed on radiographic examination. All three cases were treated conservatively by box rest. In one case slight further displacement of the fracture occurred three weeks after the initial injury but all the fractures went on to heal. The three horses returned to work but two were limited to light ridden exercise.

Animals↗
PubMed1989

Long incomplete longitudinal fractures of the third metacarpal and metatarsal bone in horses.

Five horses with long incomplete longitudinal fractures of the third metacarpal bone and three horses with similar fractures of the third metatarsal bone were examined. In three of the metacarpal fractures a long incomplete fissure extended proximomedially, in association with the more common lateral condylar fracture of the third metacarpal bone, and in the other two cases the fracture originated from the medial aspect of the distal articular surface. In the three horses with fractures of the third metatarsal bone the fractures had a consistent spiral configuration.

Animals↗
PubMed1981

Carpet beetle dermatitis.

A 22-year-old man presented with a 5-year history of recurrent urticarial and papulovesicular lesions. Careful history suggested a close examination of his environment. The woolen rug in his bedroom was infested with larvae of a carpet beetle. The insect was identified as Anthrenus verbasci. Fumigation of the house with sulfuryl fluoride (Vikane) resulted in complete clinical recovery. Intradermal injection of the antigenic extract from the larvae showed a wheal and erythema on the patient's skin, and not on normal controls. This suggests that the patient had immediate-type hypersensitivity to some of the antigens extracted from larvae. Electron microscopic pictures of the insect are presented.

Adult↗
PubMed1980

Cytoplasmic incompatibility in natural populations of a mosquito, Culex pipiens L.

When two strains of Culex pipiens (s.l.) of different geographical origin are cross-mated, the cross is frequently sterile in one or both directions. Such incompatibility is said to be cytoplasmic because the crossability of a strain is determined by its maternal lineage. The incompatibility is caused in some way by infection with a rickettsia-like bacterial symbiote, as removal of the symbiote abolishes the incompatibility. In compatibility has not been observed in crosses of American strains of C. pipiens. On the other hand, most workers in other parts of the world who have crossed C. pipiens strains have noticed incompatibility, although there are no reports of incompatible egg rafts being collected in the field. We now report incompatibility in crosses of sympatric American strains of C. pipiens and the collection of incompatible egg rafts in the field.

Animals↗