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R M Stein

Publications and source records attributed to R M Stein.

62 records · Page 4Linked to original sources
PubMed1967

Effects of hypotonic saline loading in hydrated dog: evidence for a saline-induced limit on distal tubular sodium transport.

We performed studies on dogs under hydrated conditions, utilizing the rate of free water formation (C(H2O)) as an index of the rate of distal tubular sodium transport. Since C(H2O) could be progressively increased with no evidence of a maximal rate during loading with hypotonic (2.5%) mannitol, it was concluded that there is no limit on distal tubular sodium transport during mannitol loading. In contrast, during hypotonic (0.45%) saline loading C(H2O) rose initially, but as urine flow (V) exceeded 25% of the filtered load C(H2O) attained maximal levels (up to 20% of the filtered load) and remained stable as V increased to 50% of the filtered load. It was concluded that saline loading progressively inhibits proximal sodium reabsorption. Initially, the distal tubule absorbes a large fraction of the proximal rejectate and sodium excretion rises slightly. Eventually, an alteration in distal sodium transport appears which culminates in a maximal rate or transport limit. This distal transport limit provoked by saline loading could not be characterized by a classical Tm as seen with glucose and does not seem to be consequent to high rates of flow through the distal tubule. Regardless of the precise nature of this limit, the major increment in sodium excretion develops during saline loading only after saline alters the capacity of the distal tubule to transport sodium.

Acetazolamide↗
PubMedDate not supplied

Corneal cooling and rehydration during photorefractive keratectomy to reduce postoperative corneal haze.

PURPOSE: An increase in corneal temperature has been implicated in subepithelial haze after surface photorefractive keratectomy. We aimed to determine if cooling the cornea by means of hydration between ablations and immediately after final surface ablation in PRK reduces haze. METHODS: One hundred five eyes of 61 patients with myopia ranging from -6.00 to -9.75 D were included. One of the surgeons irrigated with cool balanced salt solution between ablation passes and immediately at the end of the surface ablation while two others did not. Results of haze grading were analyzed at the end of 3 and 6 months and 1 year after PRK by an independent examiner. RESULTS: Haze was significantly reduced in those eyes in which irrigation (cooling) with balanced salt solution was performed intraoperatively and immediately after ablation. CONCLUSION: Cooling and rehydration of the cornea with chilled balanced salt solution between passes during PRK significantly reduces haze in patients with baseline myopia between -6.00 and -9.75 D.

Adult↗