Stop-flow analysis applied to the excretion of hemoglobin

1960 ◽  
Vol 199 (2) ◽  
pp. 292-294 ◽  
Author(s):  
C. L. Malmendier ◽  
J. P. DeKoster ◽  
F. Vander Veiken ◽  
H. Brauman ◽  
M. DeMyttenaere ◽  
...  
Keyword(s):  
Flow Analysis ◽  
Middle Part ◽  
The Other ◽  
Physiological Data ◽  
Sodium Reabsorption ◽  
Water Reabsorption ◽  
Tubular Lumen ◽  
Influence Of Water ◽  
Stop Flow ◽  
Ureteral Occlusion

The stop-flow analysis has been applied to the study of the excretion of hemoglobin, in order to compare the physiological data with the morphological views. The study of the ratio U/P hemoglobin/U/P creatinine suggests that this protein penetrates the tubular lumen by diffusion during the ureteral occlusion and progressed slowly under influence of water reabsorption. During this migration, hemoglobin undergoes the effects of a double reabsorption: one in the middle part of the proximal convoluted tubule, the other more distally situated in a zone not distinguishable from the site of sodium reabsorption.

Stop flow analysis of renal function in the monkey

1962 ◽  
Vol 202 (6) ◽  
pp. 1105-1108 ◽  
Author(s):  
Arthur J. Vander ◽  
Edward J. Cafruny
Keyword(s):  
Renal Function ◽  
Proximal Tubule ◽  
Flow Analysis ◽  
Macaque Monkey ◽  
Sodium Reabsorption ◽  
Glucose Reabsorption ◽  
Proximal Tubular ◽  
Potassium Secretion ◽  
Stop Flow ◽  
Ureteral Occlusion

Stop flow analysis has been used to study renal function in the macaque monkey. Mannitol diuresis produced excretion of 58–70% of filtered water and 22–34% of filtered sodium. An absence of water and sodium reabsorption from the proximal tubule during ureteral occlusion was observed in three of four experiments, suggesting that this portion of the monkey nephron cannot transport sodium as efficiently as the canine proximal tubule during osmotic diuresis or that it is less permeable to water. Creatinine secretion was observed and localized to the same portion of the proximal tubule which secretes PAH. Inorganic phosphate and glucose reabsorption also occurred in the proximal tubule. Sodium, chloride, and potassium stop flow patterns were identical to those reported for the dog. Chlorothiazide caused an inhibition of distal tubular sodium reabsorption and an enhancement of potassium secretion in the distal nephron. Proximal tubular activity of the drug could not be evaluated.

Cadmium enhancement of proximal tubular sodium reabsorption

1962 ◽  
Vol 203 (6) ◽  
pp. 1005-1007 ◽  
Author(s):  
Arthur J. Vander
Keyword(s):  
Free Flow ◽  
Sodium Reabsorption ◽  
Untreated Animal ◽  
Sodium Gradient ◽  
Proximal Tubular ◽  
Renal Sodium Reabsorption ◽  
Stop Flow ◽  
Ureteral Occlusion ◽  
Distal Site ◽  
Rule Out

Stop-flow studies were performed to localize the site of cadmium action on renal sodium reabsorption. In the untreated dog undergoing mannitol diuresis, a maximal lumen:plasma sodium gradient was established across the proximal tubule during free flow with no further lowering of luminal concentration during ureteral occlusion, Naprox/NaFF = 1.02 ± .05. During occlusions after cadmium, sodium concentrations in proximally trapped fluid were reduced below free-flow values, Naprox/NaFF = 0.85 ± .08. This difference between treated and untreated animals was statistically significant ( P = < .001) and indicates that cadmium enhances proximal sodium reabsorption. Although distal sodium patterns were unaltered by cadmium, it was not possible to rule out a possible distal site since distal sodium reabsorption is already virtually complete during occlusion in the untreated animal. Cadmium, given intravenously as Cd115, was not excreted in the urine.

Localization of the Site of Action of Mercurial Diuretics by Stop Flow Analysis

1958 ◽  
Vol 195 (3) ◽  
pp. 558-562 ◽  
Author(s):  
Arthur J. Vander ◽  
Richard L. Malvin ◽  
Walter S. Wilde ◽  
Lawrence P. Sullivan
Keyword(s):  
Proximal Tubule ◽  
Flow Analysis ◽  
Distal Tubule ◽  
Sodium Concentration ◽  
New Technique ◽  
Osmotic Diuresis ◽  
Site Of Action ◽  
Stop Flow ◽  
Ureteral Occlusion ◽  
Lower Urinary

Experiments utilizing the new technique of ‘stop flow’ analysis have been performed to localize the renal site of action of mercurial diuretics. Control ureteral occlusions were done on dogs after stabilization of mannitol osmotic diuresis. After release of occlusion and collection of samples, either thiomerin or meralluride (4–8 mg Hg/kg) was administered and a second occlusion performed forty minutes later. The mercurials caused at least a 50% reduction in the mass of water and sodium reabsorbed by the proximal tubule during the brief period of occlusion. These reductions were equivalent so that the sodium concentration of the proximal reabsorbate always remained plasma-like. The mercurials did not interfere with the ability of the distal tubule to lower urinary sodium concentration during the period of ureteral occlusion.

Graphical Placement of Transport Segments Along the Nephron From Urine Concentration Pattern Developed With Stop Flow Technique

1958 ◽  
Vol 195 (1) ◽  
pp. 153-160 ◽  
Author(s):  
Walter S. Wilde ◽  
Richard L. Malvin
Keyword(s):  
Sodium Concentration ◽  
Urine Concentration ◽  
Free Flow ◽  
Sodium Reabsorption ◽  
Glucose Phosphate ◽  
Concentration Pattern ◽  
Glucose Reabsorption ◽  
Stop Flow ◽  
Ureteral Occlusion ◽  
Proper Length

The authors characterize transport within segments at points along the nephron by the concentration pattern developed along the renal tubule during stopped flow (brief ureteral occlusion during osmotic diuresis in dogs). The pattern is caught in serial urine samples on reinstatement of flow. They here develop a system of graphical construction which places active transport segments of proper length and position to account for the concentration patterns developed for the substances: Sodium, glucose, phosphate and para-aminohippurate (PAH). The system is based on mixing phenomena as nephrons of different length deliver their fluid content into mixed samples. Glucose reabsorption, phosphate reabsorption and PAH secretion occur in identical proximal segments, containing 45% of the total stop flow nephron volume. A far distal area for very effective active sodium reabsorption contains about 29% of the occluded nephron volume. The sodium concentration pattern does not delineate its own proximal segment but forms a plateau in that area. This results from the fact that proximal concentrations are not lowered during stop flow but remain the same as in new flow and free flow proximal fluid, no lower than the 30–60 mm concentration of free flow urine itself, considerably higher if distal removal of Na occurs during the new outflow.

Actions of vasotocin and some of its analogues on salt and water excretion by the frog

1963 ◽  
Vol 204 (2) ◽  
pp. 222-226 ◽  
Author(s):  
Serge Jard ◽  
Francois Morel
Keyword(s):  
Free Water ◽  
Rana Esculenta ◽  
The Other ◽  
Sodium Reabsorption ◽  
Water Reabsorption ◽  
Water Excretion ◽  
Lysine Vasopressin ◽  
Target Organs ◽  
Small Doses ◽  
Stimulation Of

The actions of small doses of arginine and lysine-vasotocin on urine flow (V), inulin (CIn), free water (CHH2O), sodium (CNa), and potassium (CK) clearances were studied in Rana esculenta and compared with those of larger doses of oxytocin, lysine-vasopressin, Val3-oxytocin, Ileu8-oxytocin, Phe2-Phe3-Lys8-oxytocin, deamino-oxytocin, and oxypressin. Injections of either arginine or lysine-vasotocin (mean dose .030 µg) induce a small decrease in glomerular filtration rate (GFR) and two marked tubular effects: a) an increase in water reabsorption, CHH2O being reduced even when related to CIn; b) an increase in tubular sodium reabsorption, CNa/CIn being lowered, whereas CK/CIn remains unchanged. Neither oxytocin nor lysine-vasopressin, even in doses 20–25 times higher, promotes the tubular effects typical of vasotocin. Oxytocin promotes a slight decrease in GFR and V. Lysine-vasopressin remains without any effect. All the other artificial analogues of oxytocin injected in large doses increase V, GFR, CNa/CIn and CK/CIn. It is concluded that the vasotocins specifically promote in the kidney tubules of the frog the same two actions described in the other target organs in the amphibians, namely an increase in osmotic permeability to water and a stimulation of active sodium transport.

Localization and Characterization of Sodium Transport Along the Renal Tubule

1958 ◽  
Vol 195 (3) ◽  
pp. 549-557 ◽  
Author(s):  
Richard L. Malvin ◽  
Walter S. Wilde ◽  
Arthur J. Vander ◽  
Lawrence P. Sullivan
Keyword(s):  
Water Movement ◽  
Flow Analysis ◽  
Peritubular Capillary ◽  
Water Reabsorption ◽  
Na Pump ◽  
Passive Mechanism ◽  
Proximal Tubular ◽  
Stop Flow ◽  
Colloidal Osmotic Pressure

The proximal tubular Na transport system was investigated using our stop flow analysis. During varying degrees of osmotic diuresis in dogs the ureter of one kidney was occluded for 2 1/2–8 minutes. Following occlusion serial urine samples were collected and analyzed for Na, creatinine, PAH or glucose. Using urinary creatinine concentrations as an index of water movement the mass of Na and water reabsorbed from the proximal segments during occlusion was calculated. In all experiments the calculations showed that the Na concentration in the proximal reabsorbate was of the same concentration which existed in plasma. Such behavior is inconsistent with a proximal Na pump which would otherwise reabsorb a supraplasma-level Na solution away from mannitol and Na in the tubule. The data suggest that Na and water transport out of the proximal tubules may be a passive process initiated by the colloidal osmotic pressure differences which exist between the intratubular urine and the peritubular capillary blood. A passive mechanism for Na and water reabsorption from the proximal segment resolves many difficulties faced by a Na pump.

Renal transport sites for K, H and NH3. Effect of impermeant anions on their transport

1960 ◽  
Vol 198 (2) ◽  
pp. 244-254 ◽  
Author(s):  
Lawrence P. Sullivan ◽  
Walter S. Wilde ◽  
Richard L. Malvin
Keyword(s):  
Negative Charge ◽  
Distal Tubule ◽  
Sodium Reabsorption ◽  
Renal Transport ◽  
Transport Mechanisms ◽  
Collecting Ducts ◽  
Tubular Lumen ◽  
Potassium Hydrogen ◽  
A Site ◽  
Stop Flow

The stop flow technique was used to locate the sites of the renal transport mechanisms for potassium, hydrogen and ammonium. Data were obtained which indicate that these cations are secreted in a very distal area of the nephron, presumably in the collecting ducts. Potassium reabsorption also occurs in a distal area immediately proximal to the secretory site. Infusions of thiosulfate, ferrocyanide and phosphate alter the stop flow concentration patterns so that secretion of the cations appears to take place throughout the distal tubule and to be coextensive with distal sodium reabsorption. No clear indication of potassium reabsorption is evident under these circumstances. It is suggested that these anions, because of the impermeability of the distal tubule to them and because of their negative charge, attract hydrogen and potassium into the tubular lumen as sodium is reabsorbed. In effect, an abnormal exchange mechanism is created at a site proximal to that where active secretion of hydrogen and potassium occurs.

The Influence of Water Regime on the Performance of Aquatic Plants

1994 ◽  
Vol 29 (4) ◽  
pp. 127-132 ◽  
Author(s):  
Naomi Rea ◽  
George G. Ganf
Keyword(s):  
Deep Water ◽  
Aquatic Plants ◽  
Water Regime ◽  
Optimal Performance ◽  
Experimental Results ◽  
The Other ◽  
Full Potential ◽  
Influence Of Water ◽  
Emergent Species

Experimental results demonstrate bow small differences in depth and water regime have a significant affect on the accumulation and allocation of nutrients and biomass. Because the performance of aquatic plants depends on these factors, an understanding of their influence is essential to ensure that systems function at their full potential. The responses differed for two emergent species, indicating that within this morphological category, optimal performance will fall at different locations across a depth or water regime gradient. The performance of one species was unaffected by growth in mixture, whereas the other performed better in deep water and worse in shallow.

Demonstration of distal tubular flux of phosphorus using modified stop-flow analysis

Metabolism ◽  
1966 ◽  
Vol 15 (6) ◽  
pp. 482-491 ◽  
Author(s):  
Bernard B. Davis ◽  
Laurence H. Kedes ◽  
James B. Field
Keyword(s):  
Flow Analysis ◽  
Stop Flow

Natriuresis in Rats Acutely Depleted of Chloride

1977 ◽  
Vol 52 (1) ◽  
pp. 23-31
Author(s):  
R. G. Luke ◽  
B. T. Khanh ◽  
R. D. Schmidt ◽  
J. H. Galla
Keyword(s):  
Sodium Bicarbonate Solution ◽  
Free Water ◽  
Sodium Reabsorption ◽  
Urinary Flow ◽  
Variable Degree ◽  
Water Reabsorption ◽  
Chloride Depletion ◽  
Sodium Load ◽  
Clearance Studies ◽  
And Control

1. Acute chloride depletion, without sodium depletion, was produced in rats by a single exchange peritoneal dialysis against sodium bicarbonate solution. Blood volume was restored after dialysis by infusion of salt-free albumin, and exogenous deoxycorticosterone and antidiuretic hormone were given. 2. Clearance studies in the period (3 h) after dialysis revealed no difference in the glomerular filtration rate or in the filtered sodium load between experimental and control rats but urinary sodium concentrations and absolute and fractional sodium excretion were significantly higher in the chloride-depleted group. 3. There was also a significant kaliuresis, increased urinary flow rate and diminished free water reabsorption. Urinary bicarbonate excretion increased to a variable degree but the major rise in anion excretion was ‘unmeasured’ (Na+ + K+ — [Cl− +HCO3− +PO43-]). 4. It is postulated that chloride depletion imposes limitations on sodium reabsorption in the ascending limb of the loop of Henle.

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