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Biomedical subjects

R Mason

Publications and source records attributed to R Mason.

At least 163 records · Page 9Linked to original sources
PubMed1979

Prophylactic transfusions of normal red blood cells during pregnancies complicated by sickle cell hemoglobinopathies.

Prophylactic transfusions of normal donor red cells were administered during 37 pregnancies to women with sickle cell anemia, sickle cell-hemoglobin C disease, or sickle cell-beta thalassemia disease. Once the diagnosis was confirmed, the transfusions were administered intermittently throughout the rest of the pregnancy in such amounts and at such frequencies that no more than 60% of the circulating red cells contained hemoglobin S and the hematocrit was above 25. The maternal mortality rate was zero and maternal morbidity as the consequence of the sickle cell hemoglobinopathy was minimal. The perinatal mortality rate was appreciably reduced when compared to that previously observed without prophylactic transfusions but perinatal morbidity was still excessive. Evidence that the intrauterine environment was compromised, in spite of the transfusions consisted of an increased frequency of growth-retarded fetuses, of meconium staining of amnionic fluid, and of ominous decelerations of fetal heart rate. Morbidity from the transfusions was troublesome. Nonetheless, it is concluded tentatively that both the mother with a sickle cell hemoglobinopathy and her fetus are likely to benefit from prophylactic transfusions of normal donor red cells administered during one pregnancy according to the protocol employed in this study.

Anemia, Sickle Cell↗
PubMed1979

Responsiveness of cells in the cat's superior colliculus to textured visual stimuli.

Responses to texture motion (visual noise) were investigated in the superior colliculus of paralysed cats, lightly anaesthetized with N2O/O2 supplemented with pentobarbitone or Althesin. Within the superficial layers two classes of texture-sensitive neurones were found: Type I units with weak responses to noise, often related to specific elements in the texture and Type II units which were driven independently of the texture structure, and tended to be recorded deep to the Type I units. Type III units recorded from the deep collicular layers were insensitive to texture. Anatomical bases for this differential sensitivity and the notion of two collicular subsystems are discussed.

Animals↗
PubMed1978

Functional organization in the cat's pulvinar complex.

The responses of 192 single units in the cat's pulvinar-complex, comprising the inferior, medial and lateral pulvinar nuclei, were studied in paralysed cats, lightly anaesthetized with N2O/O2 supplemented with pentobarbitone. About 60% of the cells were visually driven and their receptive fields classified as either diffuse, concentric, movement sensitive, direction sensitive or orientation sensitive. The response fields of such cells were commonly large. Response field maps for the movement and direction sensitive cells formed a heterogenous population with uniform on-off fields to more complex arrangements with on- or off-centres, often with only partial surrounds; other cells responded exclusively to moving stimuli. A dual representation of the visual field was found in the pulvinar-complex corresponding to the striate and tectal recipient zones described anatomically by others. The representation in the striate recipient zone comprised an oblique column running medio-laterally and rostro-caudally through the inferior pulvinar and lateral margin of the medial pulvinar. The peripheral visual field was represented laterally and the vertical meridian medially; the upper visual field was represented dorso-laterally in the medial pulvinar and the lower visual field caudo-ventrally within the inferior pulvinar. That this visuotopic organization corresponded to the striate recipient zone was established by tracing the retrograde transport of HRP. Medial to the striate zone evidence for a second visual field representation was found, apparently more randomly organized than the striate zone, corresponding to the presumed tectal recipient zone. These results support the assertion that cytoarchitectural boundaries do not necessarily delineate functional (visuotopically organized) regions. These observations suggest caution when comparing cytoarchitecturally defined regions between species; rather, 'functionally equivalent' regions should be compared.

Animals↗