The FOX family of transcription factor genes is an evolutionary conserved, yet functionally diverse class of transcription factors that are important for regulation of energy homeostasis, development and oncogenesis. The proteins encoded by FOX genes are characterized by a conserved DNA-binding domain known as the forkhead domain (FHD). To date, disease-causing mutations have been identified in eight human FOX genes. Many of these mutations result in single amino acid substitutions in the FHD. We analyzed the molecular consequences of two disease-causing missense mutations (R121H and S125L) occurring in the FHD of the FOXC2 gene that were identified in patients with hereditary lymphedema with distichiasis (LD) to test the predictive capacity of a FHD structure/function model. On the basis of the FOXC2 solution structure, both FOXC2 missense mutations are located on the DNA-recognition helix of the FHD. A mutation model based on the parologous FOXC1 protein predicts that these FOXC2 missense mutations will impair the DNA-binding and transcriptional activation ability of the FOXC2 protein. When these mutations were analyzed biochemically, we found that both mutations did indeed reduce the DNA binding and transcriptional capacity. In addition, the R121H mutation affected nuclear localization of FOXC2. Together, these data indicate that these FOXC2 missense mutations are functional nulls and that FOXC2 haploinsufficiency underlies hereditary LD and validates the predictive ability of the FOXC1-based FHD mutational model.
Background: Ambiguity exists as to which preservation solution is the most effective for small bowel (SB); studies have shown equivalent results with normal saline and University of Wisconsin (UW) solution. This study was designed to investigate the requirement of SB for oncotic and osmotic support, thereby reassessing one of the key principles of static organ storage. Methods: Rodent SB was vascularly flushed with the following solutions: group 1, 0.9% saline (154 mM NaCl); group 2, 154 mM NaCl π5% dextran; group 3, 104 mM NaCl π100 mM lactobionate π5% dextran; and group 4, UW solution. Analysis of cellular energetics, permeability and histology (by electron microscopy) was performed over a 10-h time course of cold storage. Results: The addition of dextran and lactobionate to a simple saline solution (group 3) resulted in superior maintenance of several key parameters of energy metabolism throughout prolonged storage. At all times, ATP/ADP and EC ratios in group 3 remained unchanged from those of freshly isolated tissue; storage in normal saline and UW solution resulted in a progressive decline between 1 and 10 h of storage. ATP was also notably greater in group 3 than in group 1 or UW after 10 h of storage. Functional parameters demonstrated significant improvements in maintaining barrier function and membrane ion/electrical activity in group 3. Of particular note, after 10 h of storage, permeability for groups 1, 3 and UW was 215, 76 and 400 nmol/cm 2 / h, respectively, compared with a fresh tissue value of 22 nmol/cm 2 /h. Scanning electron micrographs revealed complete epithelial denudation of bowel stored 236 in simple saline and UW solutions at 10 h. The incorporation of 100 mM lactobionate plus 5% dextran in group 3 prevented extensive villus denudation; the presence of intact microvilli indicated normal epithelial cell morphology. Conclusion: The order of solution effectiveness was group 3 Ͼ group 2 Ͼ group 1 Ͼ group 4. Vascular supplied impermeants, when supplied in simple solution, provide markedly improved preservation of metabolism, barrier function, and morphology of SB compared with UW.
Background/Purpose:
There is limited research regarding the consequences of treating lactating mothers with intravitreal anti–vascular endothelial growth factor (VEGF) agents. Balancing the need for vision-saving treatment, the benefits of breastfeeding, and the concern for affecting the newborn can present a conflict for both mothers and ophthalmologists. This review summarizes the state of the literature regarding the use of intravitreal anti-VEGF agents during breastfeeding along with details about their pharmacology.
Results:
Bevacizumab and aflibercept have Fc domains subjecting them to FcRn recycling and extending their half-life compared with ranibizumab which is an antibody fragment and lacks the Fc domain. Case reports and small studies have shown that ranibizumab has the lowest serum concentration after intravitreal injection and the least effect on plasma-free VEGF concentrations and breastmilk VEGF levels.
Conclusion:
Clinical and pharmacologic data suggest that ranibizumab has less systemic circulation and effect on maternal serum and breastmilk VEGF levels when compared to bevacizumab and aflibercept. However, there is significant need for further research on the degree and duration to which intravitreal agents circulate systemically, what fraction is transferred into breastmilk and is absorbed, and whether this results in any functional adverse effects to the infant. Other factors to consider in the medical decision-making of lactating mothers necessitating intravitreal anti-VEGF treatment include the gestational and post-natal age of the child and whether it is feasible to avoid breastfeeding for the half-life duration of the intravitreal agent rather than ceasing breastfeeding altogether.
This study strongly supports that the beneficial effects of gln-enriched UW solution can be amplified when combined with an effective buffering agent such as BES.
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