Extirpation of cranial neural crest cells in presomite to 5 somite chick embryos produces monsters which in all essential respects are identical to human cyclopias. The primary lesion involves damage to the forebrain and consequently the inhibition of the nasal placode and nasal organ development as well as the destruction of the anterior neural crest cells, with the resultant absence of the nasal and interobital septa and of the facial dermal skeleton.
The topology of membrane phospholipids in the red cells of patients with hereditary spherocytosis has been studied with the non-penetrating probe 2,3,5-trinitrobenzenesulphonate. There was no significant difference in the assymetric distribution of the aminophospholipids phosphatidylserine and phosphatidylethanolamine across the two halves of the membrane bilayer in red cells of five patients with hereditary spherocytosis as compared to seven normal controls. These studies indicated that the complex processes responsible for membrane lipid assymetry are intact in hereditary spherocytosis.
Previous human studies have shown that drinking tea during meals significantly inhibits the absorption of both food iron and medicinal iron. This study provides evidence from experiments with rats that the tannins in the tea are responsible for the inhibition, probably by forming non-absorbable complexes with the iron within the intestinal lumen. The molar ratio of tannin: iron is dependent on the pH, being 1:1 at pH 2,0 2:1 at pH 5,5 and 3:1 at pH 8,0. Since tannins are present in many vegetable foods the formation of such complexes may be a factor in the poor availability for absorption of much food iron.
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