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Biomedical subjects

C Breen

Publications and source records attributed to C Breen.

8 recordsLinked to original sources
PubMed1991

Neonatal macular hemorrhage.

Retinal hemorrhages occur with increased frequency in neonates following prolonged or difficult labor, especially if associated with primipara, surgical or mechanical intervention, low Apgar scores, perinatal hypoxia, low birth weight or coagulopathy. When involvement occurs peripheral to the arcades resolution occurs generally without sequelae. Hemorrhages involving the macula are much more serious since resolution in these cases may result in degenerative changes or an exudative or glial scar, resulting in amblyopia and possible strabismus. Early examination is warranted in high-risk infants in order to facilitate intervention and the prevention of more serious visual sequelae.

Adult↗
PubMed1990

Scanning electron microscopy of corneal incisions using steel, diamond, and sapphire blades.

In order to compare the wound morphology they produce, we used steel (Myocure), diamond (CILCO DK 121), and sapphire (Katena K2-6500) blades, to make parallel linear incisions, 500 microns deep, in 12 fresh enucleated porcine eyes. There was no discernible difference among the blades in terms of either the morphology of the collagen lamellae of the sides or the depth of the incisions produced. The major differences in the cuts produced were attributable primarily to the differences in the footplates.

Animals↗
PubMed1989

Ductus arteriosus: involvement of a sarcolemmal cytochrome P-450 in O2 constriction?

Our previous studies implicate a cytochrome P-450-based mechanism in the constrictor response of the ductus arteriosus to oxygen. The present experiments were conducted on saponin-skinned strips of ductal muscle from mature fetal lambs to determine the location, sarcolemmal versus intracellular, of this cytochrome and to obtain a better insight into the sequence of events underlying the action of oxygen. Skinned preparations contracted to free Ca2+ over the range between 0.1 and 5-10 microM (pCa 7 to 5). In contrast, oxygen (PO2, 608-690 Torr; 1 Torr = 133.3 Pa) had no significant effect, both in the absence and presence of 10 microM calcium. Carbon monoxide, tested as pure CO or a CO-O2 mixture (ratio 0.28), did not relax preparations maximally contracted with calcium. These findings indicate that oxygen exerts its effect on the plasma membrane of ductus muscle cells and that a membrane-bound cytochrome P-450 mechanism likely functions as the signal transducer for oxygen in the formation of a constrictor agent.

Animals↗
PubMed1986

Teaching social language to moderately handicapped students.

Three students with moderate handicaps were taught to initiate and expand on conversational topics. The teaching procedure used stimuli generated from actual conversations with nonhandicapped peers. Generalization was assessed by audiotaping conversations between the handicapped students and their peers in natural school contexts without adult supervision. Results indicated that training generalized to natural contexts. These results were socially validated by undergraduate special education students, who rated tapes of two of the students' conversations during training phases as more socially competent than during baseline. Results are discussed in terms of the evaluation of complex social behavior as multioperant behaviors.

Adolescent↗
PubMed1974

A comparative study of some commercially available tests for rheumatoid factor.

Seven commercially available screening tests for rheumatoid factor and two quantitative tests have been compared with the standard Rose-Waaler test in a series of 477 sera from patients with various joint diseases. Markedly different results were obtained, and on the basis of our findings suggestions are made as to what we consider to be the most satisfactory currently available tests.

Animals↗