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R W Berliner

Publications and source records attributed to R W Berliner.

At least 19 recordsLinked to original sources
PubMed1999

Origins of renal physiology in the USA.

Research in renal physiology began later in the USA than in Europe. Initial studies in the early 1900s dealt with the pathophysiology of renal failure. Micropuncture study of single nephron function was initiated in the laboratory of A.N. Richards in the early 1920s and with the later addition of microperfusion provided important insights into the site and mechanisms of solute transport. In parallel, with the leadership of Homer Smith, the development of noninvasive clearance methods to measure glomerular filtration rate and renal blood flow initiated a fruitful period of quantification of renal hemodynamics and of transport by the tubules. The steady progress of renal physiology in the USA owes much to the generous support of basic research by the National Institutes of Health. It is also worthy of mention that progress in renal physiology in the US owes much to work carried out in clinical departments and to the type of comparative studies exemplified by work at the Mt. Desert Island Biological Laboratory.

History, 19th Century↗
PubMed1990

Distal perfusion studies: transport stimulation by native tubule fluid.

It is well established that potassium secretion into the distal tubule increases with the rate of flow. In a previous study [G. Malnic, R. W. Berliner, and G. Giebisch. Am. J. Physiol. 256 (Renal Fluid Electrolyte Physiol. 25): F932-F1271, 1989] we found that the increase with the rate of perfusion with a fluid made up to resemble that normally found in the early distal tubule was substantially less than the increase in free-flow conditions [R. N. Khuri, M. Wiederholt, N. Strieder, and G. Giebisch. Am. J. Physiol. 228: 1249-1261, 1975]. Because of the possibility that some important component was missing from the artificial fluid, we have carried out another series of experiments in which distal tubules were perfused with fluid collected from late proximal tubules and compared the results with those obtained when tubules were perfused with an artificial fluid with an electrolyte composition similar to that of late proximal fluid. When proximal tubule fluid was used, the potassium concentrations in the collected distal fluid were higher and better maintained with increasing flow than when the artificial fluid was used, and consequently the rate of potassium secretion was substantially greater with the proximal tubule fluid, approaching the results of previous studies in free flow. The nature of the component missing from the artificial solution is not known.

Absorption↗
PubMed1989

Flow dependence of K+ secretion in cortical distal tubules of the rat.

Superficial distal tubules were pump perfused (range 0-35 nl/min), generally with solutions similar in composition to early distal tubule fluid, in control, K+-depleted, acutely K+-loaded, and K+-adapted rats with the use of double-barreled resin-reference microelectrodes to measure K+ and Na+ activities and transepithelial potential differences (PD). When perfusion rate decreased from 35 to 5 nl/min in control animals, [K+] increased from 2 mM to between 10 and 20 mM, remaining at these levels as perfusion rate was decreased further. In low-K+ rats, the change in K+ activity with flow was greatly attenuated. In K+-loaded and K+-adapted rats, [K+] was higher than in controls at all flow rates. Na+ concentrations and lumen-negative PD increased with high flow rates in control rats. Addition of 10(-3) M amiloride blocked the increase in luminal K+ with low flow rates. In the physiological range of late distal flow rates, luminal [K+] remains constant and similar to the concentration attained in the steady state. At higher flow rates, [K+] declines, and K+ balance, PD, and Na+ reabsorption modulate the relationship between K+ secretion and flow rate.

Amiloride↗