Publications by authors named "C Darrow"
Efficient distribution of oxygen (O) to the tissues in mammals depends on the evolved ability of red blood cell (RBC) hemoglobin (Hb) to sense not only O levels, but metabolic cues such as pH, PCO, and organic phosphates, and then dispense or take up oxygen accordingly. O delivery is the product of not only oxygen release from RBCs, but also blood flow, which itself is also governed by vasoactive molecular mediators exported by RBCs. These vascular signals, including ATP and S-nitrosothiols (SNOs) are produced and exported as a function of the oxygen and metabolic milieu, and then fine-tune peripheral metabolism through context-sensitive vasoregulation.
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- The study investigates the stability of nucleic acid bases, including adenine, cytosine, guanine, thymine, uracil, and 2,6-diaminopurine, in concentrated sulfuric acid over a year at room temperature.
- Researchers found that these organic molecules remain stable in acid concentrations similar to those found in Venusian clouds (81% - 98% sulfuric acid).
- This finding suggests that the harsh conditions of Venus clouds might support complex organic chemicals, which could have implications for understanding potential life in extreme environments.
What constitutes a habitable planet is a frontier to be explored and requires pushing the boundaries of our terracentric viewpoint for what we deem to be a habitable environment. Despite Venus' 700 K surface temperature being too hot for any plausible solvent and most organic covalent chemistry, Venus' cloud-filled atmosphere layers at 48 to 60 km above the surface hold the main requirements for life: suitable temperatures for covalent bonds; an energy source (sunlight); and a liquid solvent. Yet, the Venus clouds are widely thought to be incapable of supporting life because the droplets are composed of concentrated liquid sulfuric acid-an aggressive solvent that is assumed to rapidly destroy most biochemicals of life on Earth.
View Article and Find Full Text PDFMetabolic homeostasis in animals depends critically on evolved mechanisms by which red blood cell (RBC) hemoglobin (Hb) senses oxygen (O) need and responds accordingly. The entwined regulation of ATP production and antioxidant systems within the RBC also exploits Hb-based O-sensitivity to respond to various physiologic and pathophysiologic stresses. O offloading, for example, promotes glycolysis in order to generate both 2,3-DPG (a negative allosteric effector of Hb O binding) and ATP.
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- Human milk is recommended for very low birth weight (VLBW) infants, but it needs to be fortified for proper nutrition, raising concerns about acidified (ALHMF) versus non-acidified (NLHMF) fortifiers.
- A study comparing 61 infants on ALHMF to 68 on NLHMF revealed that 70.5% of those on ALHMF developed metabolic acidosis compared to just 11.8% on NLHMF, along with lower growth rates during the fortification period.
- Although no overall growth differences were observed by the end of hospitalization, the initial findings suggest that further research is warranted to evaluate the long-term effects of each type of fortifier.