A pregnant woman with severe epistaxis--a rare manifestation of folic acid deficiency.

The case-history of a pregnant woman with a life-threatening thrombocytopenia, due to folic acid deficiency, caused by an extremely low dietary intake is described. As folic acid deficiency manifests itself in a variety of ways, its clinical features are not always easily recognized. Timely recognition is important because of the rapid progressive nature of the disorder, especially in pregnancy, and because rapid improvement is achieved by simple treatment: supplementation of the deficiency. This is well illustrated in the patient described in this case report. A short review of the literature is presented.

Origin of the impedance cardiogram investigated in the dog by exchange transfusion with a stroma-free haemoglobin solution.

In an anaesthetized dog an exchange transfusion was carried out with stroma-free haemoglobin solution. The total circulating blood volume was kept constant. The heart-syncronous changes in the thoracic electrical impedance (Zo) were measured before and after the exchange transfusion. Zo consists of a parallel connection of a tissue impedance (Zt) and a blood impedance (Zb). With the aid of this model for Zo the relative variations in Zb (delta Zb/Zb) were calculated from the relative variations in Zo (delta Zo/Zo). The marked decrease of delta Zb/Zb during the experiment can only be explained by the fact that apart from the heart-synchronous changes in vascular volume the impedance changes are also caused by flow dependent changes in the electrical conductivity of blood caused by variations in orientation of the erythrocytes.