Migraine and motion sickness independently contribute to visual discomfort.

The objective of this study was to evaluate, in patients with migraine and healthy volunteers, with and without a history of motion sickness, the degree of discomfort elicited by drifting striped patterns. Eighteen healthy volunteers (HV) and 30 migraine patients participated in the study. Discomfort was greater in migraine patients than in HV, and in individuals with a history of motion sickness than in those without, but the effect of history of migraine was independent of history of motion sickness. Generalized Estimating Equations models for binary correlated data revealed that these differences did not depend on levels of duty cycle, spatial and temporal frequencies. Visual discomfort in migraine patients was associated with worse performance. There was a significant correlation between median degree of discomfort across conditions and number of migraine attacks in the past month. Discomfort to drifting striped patterns may be related to central sensitization in migraine patients.

A study of erythropoiesis and iron metabolism in the rabbit in vivo. II. Dependence of the response on iron storage and transport.

Rabbits subjected to a daily bloodletting schedule of 10 ml blood per kg body weight increase four- or fivefold their erythropoietic production compared to normal non-bled animals. The maximum response they can reach under these conditions mobilizes more than 9 mg of iron per day per rabbit into hemoglobin. When fed ad libitum with their regular diet, they do not need any further iron supplement for full erythropoiesis. The experimental increment in iron body stores and/or serum iron levels does not enhance their erythropoietic response, demonstrating that iron is not rate limiting under the conditions studied. Furthermore, although serum iron levels are elevated onefold in the controls under chronic anemia with respect to non-bled animals, the concentration of serum transferrin is only slightly increased; hence, the iron saturation of this protein changes from a 50% to an 80% level. In the absence of an extra supplement of iron, rabbits subjected to chronic bloodletting show no signs of body iron depletion, as judged by their continuous macrocytic RBC production.