The riddle of vitamin K1 deficit in the newborn
| Autor: | Lyonel G. Israels, Satya Saxena, Esther D. Israels |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Adult
Vitamin Aging medicine.medical_specialty Storage pool Cell Mitosis Receptor tyrosine kinase Embryonic and Fetal Development chemistry.chemical_compound Risk Factors Internal medicine medicine Humans Phosphorylation Fetus biology Embryogenesis Infant Newborn Obstetrics and Gynecology Vitamin K 1 Protein-Tyrosine Kinases Endocrinology medicine.anatomical_structure chemistry Hemostasis Pediatrics Perinatology and Child Health biology.protein |
| Zdroj: | Seminars in Perinatology. 21:90-96 |
| ISSN: | 0146-0005 |
| DOI: | 10.1016/s0146-0005(97)80024-9 |
| Popis: | Vitamin K in the fetus and newborn is maintained at levels less than that necessary to achieve full gamma-carboxylation of the K-dependent proteins, including those required for hemostasis. As the infant matures and even into adulthood, there is no significant storage pool for this vitamin, and a K1-deficient state can be produced by placing an adult on a K-deficient diet for 7 to 10 days. Questions arise as to why the level of vitamin K is so rigidly controlled and why the placental gradient in humans and other mammals maintains the fetus in a K-"deficient" state. The evidence is reviewed that suggests that K-dependent proteins are ligands for receptor tyrosine kinases, which, in the rapidly proliferating cell milieu of the fetus, control growth regulation. Increased stimuli may result in growth dysregulation whereas conversely, the further depletion of vitamin K-dependent proteins, as in warfarin toxicity, depletes the required stimuli for normal embryogenesis. These findings argue for the need for tightly controlled levels of vitamin K consistent with normal embryogenesis. |
| Databáze: | OpenAIRE |
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