Biomedical subjects
Publications and source records attributed to A E Hellegers.
After direct infusion of a carbonic anhydrase inhibitor to the fetus the fetal PCO2 increased to 70-80 mm Hg. Under the conditions of our sheep preparation no changes were seen in uterine or umbilical blood flows.
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This investigation was undertaken to study the effect of reduction of placental surface area on fetal growth. The right horn of the bicornuate uterus was removed in nonpregnant ewes, the ewes were bred and 11 out of 15 became pregnant. Near term, under experimental conditions, maternal and fetal blood gases, pH, uterine and umbilical blood flows were measured or calculated. Fetal, placental membrane, uterine, and cotyledonary weights and number of cotyledons were recorded. The experimental hemi-hysterectomized group was compared to a control group of 14. Results show that: (1) weight per cotyledon was significantly greater (p less than 0.01) in the hemi-hysterectomized series than in the controls, (2) loss of a significant number of placentation sites was compatible with the production of term-sized fetuses, (3) since the difference between the number of cotyledons in the hemihysterectomized and control groups is significantly less than the number of implantation sites removed, the efficiency of implantation is improved, and (4) there were no changes in blood flows, PO2, PCO2, and fetal oxygen consumption.
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Blood of patients with sickle cell anemia (SS) exhibits decreased affinity for oxygen, although the oxygen affinity of hemoglobin S is the same as that of hemoglobin A. SS red cells contain more 2,3-diphosphoglycerate (DPG) than normal erythrocytes. The oxygen affinity of hemolyzed red cells is decreased by added DPG, and hemolysates prepared from SS red cells do not differ from normal hemolysates in this regard. Reduction of oxygen affinity to the levels found in intact SS red cells required DPG concentrations in excess of those found in most SS patients. The same was true of oxygen affinity of patients with pyruvate kinase deficiency. Other organic phosphates, as well as inorganic ions, are known to alter the oxygen affinity of dilute solutions of hemoglobin. These substances, the state of aggregation of hemoglobin molecules, and cytoarchitectural factors probably play roles in determining oxygen affinity of both normal and SS red cells.
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