= Juha P. Kokko
{c}
<Juha P. Kokko> investigated the segment-specific transport properties of the <nephron>. His experiments with isolated rabbit <renal tubules> examined how movement of <sodium chloride> and <water> contributes to the concentrating function of the <kidney>.<Sodium chloride and water transport in the descending limb of Henle by Juha P. Kokko>[Byline and Abstract: isolated descending-limb experiments]{ref}
In a 1970 study of the <thin descending limb>, raising the <osmolality> of the surrounding bath drew <water> out of the tubule. Concentration of the remaining fluid occurred mainly through water loss rather than substantial entry of <sodium chloride>. The preparation showed relatively high water permeability and low sodium permeability under the tested conditions.<Sodium chloride and water transport in the descending limb of Henle by Juha P. Kokko>[Abstract: hyperosmotic bath, measured permeability and water-efflux interpretation]{ref}
A later study with <Antonino S. Rocha> demonstrated a different combination in the <thick ascending limb>: salt removal with very little net water movement. Comparing the two segments makes their complementary functions clearer than describing the entire <Loop of Henle> as having one permeability.<Sodium chloride and water transport in the medullary thick ascending limb of Henle. Evidence for active chloride transport by Antonino S. Rocha and Juha P. Kokko>[Abstract: salt transport with low osmotic water permeability]{ref}
For example, concentrating a solution by removing <water> and diluting it by removing <sodium chloride> are different operations. Distinct neighboring segments can perform these operations within the same <nephron>.
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