Stop-flow Technique Research Articles

Localization of the renal excretion of the tritiated digoxin.

Abstract:Since digoxin is excreted principally in the urine as the unchanged glycoside in patients with or without congestive heart failure, the mechanism of renal excretion is important. The site of renal digoxin excretion was studied in ten dogs by the stop-flow technique after the intravenous inj

Renal tubular secretion and biosynthesis of organic acids.

SummaryWith the in vitro kidney slice technique, the in vivo steady state and stopflow technique, we have studied the sites and the interrelationship of tubular secretion and biosynthesis of organic acids and found that both occur in the cortex, in the same proximal segment and probably in the same cells. Addition of transported substance, such as PAH or Diodrast, in the medium does not alter the rate of biosynthesis. Simultaneous administration of aminobenzoic acid does not augment, but exhibits either no effect or a slight decrease of tubular transport maximum of the aminohippurate. However, administration of Diodrast would markedly depress the urinary excretion of aminohippurate either by administration or by biosynthesis. Our results indicate that the second step of the transport process, from cell to lumen, is carrier-mediated, and that this carrier can be saturated at a Tm level.

Characterization of the natriuretic action of clopamide (DT-327)

Administration of clopamide to anesthetized dogs produced a marked increase in the excretion of water and electrolytes over a wide pH range without altering glomerular filtration rate. The effect of the drug on bicarbonate excretion was slightly enhanced during metabolic alkalosis. Infusion of clopamide into the left renal artery produced an ipsilateral increase in sodium excretion and urine flow which could be reduced with probenecid. Intravenous injection of clopamide had no effect on renal blood flow or mean blood pressure. Clopamide caused a significant increase in the distal sodium minimum as determined by a stop-flow technique. Ex-4877, which specifically blocks It is concluded that the site and predominant mechanism of action of clopamide cannot be distinguished from that benzothiadiazine natriuresis, significantly decreased the natriuretic effect of clopamide but not that of furosemide. of the thiazides.

Glucose excretion in man and dog.

The normal rates of glucose excretion in man and dog were measured, and the effects of water diuresis, osmotic diuresis, and plasma glucose concentration on glucose excretion were studied by the clearance method. The possibilities of more complete glucose reabsorption and glucose secretion were examined with the stop-flow technique in dogs. In unfasted human subjects, glucose excretion rate was higher in the afternoon and evening and correlated with urine flow rate. In fasted human subjects, water loading did not alter glucose excretion; whereas, water loading of fasted trained dogs increased glucose excretion and clearance. With mannitol osmotic diuresis induced in dogs undergoing maximal water diuresis, glucose clearance was approximately proportional to the urine volume flow rate. In both human subjects and dogs, glucose clearance was not significantly altered by moderate variation in plasma glucose levels. Stop-flow experiments on anesthetized dogs demonstrated that under these conditions glucose is added to the urinary fluid stopped in renal pelvis or collecting duct; however, this phenomenon is probably not a significant determinant of glucose excretion during normal free-flow. Glucose reabsorption by the proximal tubule was not as complete during stop-flow as during free-flow and indicates that failure of glucose to be completely reabsorbed is not caused by insufficient time for reabsorption. The findings are consistent with the concept that glucose excretion is normally determined by the volume flow rate from the proximal tubule and by the glucose concentration gradient finally effected across the epithelium.

Effects of diazoxide on renal function in the dog.

SummaryRenal clearance and stop flow studies were done in dogs before and after infusion of diazoxide directly into the left renal artery. In all animals the left kidney showed a prompt diuresis, natriuresis and increase in creatinine or inulin clearance when diazoxide was given. No inhibition of distal tubular sodium reabsorption following diazoxide administration was found using the stop flow technique. The natriuresis produced by infusing diazoxide directly into the renal artery is probably due to renal vasodilation and resulting changes in intrarenal hemo-dynamics.

The reactions of organometallic compounds containing silicon. Part I. Reactions of dimethylphenyl-, methyldiphenyl-, and triphenyl-silyllithium with 1,1-diphenylethylene

Dimethylphenyl-, methyldiphenyl-, and triphenyl-silyl-lithium react very rapidly with 1,1-diphenylethylene in tetrahydrofuran but the reaction can be followed at low temperature using a stop-flow technique. The thermodynamic constants of activation at –40° for this reaction (R3SiLi + H2C:CPh2→ R3Si·CH2·CPh2– Li+) with Ph3SiLi, MePh2SiLi, and Me2PhSiLi, respectively, are : ΔG‡= 12·8, 12·3, and 12·4 kcal. mole–1; ΔH‡= 3·4, 3·05, and 3·4 kcal. mole–1; ΔS‡=–40·3, –39·8, and –38·7 cal. mole–1 deg.–1. The addition products show an absorption maximum at 506 mµ(Iµ= 2·7 × 104).

Studies of the carbon dioxide and oxygen tensions of urine during application of the stop-flow technique.

Studies by the stop–flow technique were carried out in dogs in which diuresis had been induced with water, with and without the addition of bicarbonate. Urine samples from the collecting duct had greater maximal CO2 tension than was recorded simultaneously in arterial blood, and this peak occurred during infusion of carbonic anhydrase as well as during its inhibition by acetazolamide. With the former procedure, curves of CO2 tension were almost identical with those in standard control experiments. After administration of acetazolamide the values were greater, even when CO2 tension in arterial blood was > 60 mm Hg; otherwise, the curves were of similar shape. Lowest values for O2 tension in urine were recorded from the collecting duct region, and they persisted when urine flow was increased by the administration of acetazolamide or when the dog breathed 100% oxygen. The curves were of similar shape but values were slightly greater during oxygen breathing. The results obtained reflect the operation of hemodynamic mechanisms in the renal medulla, during application of the stop–flow technique.

Viruria in dogs after injection of coxsackie B-1 virus into a renal artery.

from blood to the urine after injection into a renal artery. Similar findings were noted after injection of virus into the aorta or into a peripheral vein. Moreover, with the stop-flow technique (6), localization of the point of initial viruria was possible. The site appears to be in a distal portion of the nephron, perhaps in the distal tubule.

Chemistry of radical ions: the absolute rate constant of dimerization of radical anions of 1 ,1-diphenyl ethylene

The combination of the labile radical ions, (Ph 2 C:CH 2 )7~, Na+, into dimeric dianions Na + , C - (Ph) 2 .CH 2 .CH 2 .C(Ph) - 2, Na+ was investigated by a flow and a stopflow technique. The bimolecular rate constant of combination was found to be 2 to 3 x 106 1. mole-1 s-1. The reaction was initiated by an electron transfer naphthalene^ + (P/*,2C:CH2) naphthalene+ (P/*,2C:CH^) or terphenylener + (P7fc2C:CH2) ⇔ terphenylene + (Pfe2C:CH^). The equilibrium constant of the first electron transfer process was found to be 20 and of the second about 16. These results are consistent with recent determinations of electron affinities of aromatic hydrocarbons.

LOCALIZATION AND PYRAZINAMIDE INHIBITION OF DISTAL TRANSTUBULAR MOVEMENT OF URIC ACID-2-C14 WITH A MODIFIED STOP-FLOW TECHNIQUE.

Renal tubular secretion of uric acid has been demonstrated in several mammalian species including the rabbit (1), mongrel and Dalmatian dog (24), and man (7). Although secretion was easily delineated in the Dalmatian coach hound (4-6), special experimental conditions were necessary for its substantiation in other species. Uric acid clearance in excess of simultaneous creatinine clearance, indicative of tubular secretion of urate, was noted by Poulsen and Praetorius in rabbits made hyperuricemic by the intravenous infusion of urate (1). In 1959, Gutman, Yfi, and Berger (7) documented tubular secretion of uric acid in patients with reduced glomerular filtration, who were given infusions of uric acid and mannitol and treated with large doses of sulfinpyrazone in order to suppress tubular reabsorption. One year later tubular secretion of urate was reported in the mongrel dog under similar conditions of an osmotic diuresis and an intravenous infusion of uric acid (2, 3). Efforts to localize the site of tubular urate secretion in the mongrel dog by stop-flow analysis have yielded conflicting results. Yu and his colleagues (3, 8) reported peak net tubular secretion in the distal segment of the nephron. However, Kessler, Hierholzer, and Gurd (6), utilizing the same experimental procedure except for the administration of probenecid, found no evidence for distal tubular secretion of urate.

ROLE OF RENAL TISSUE CALCIUM IN ALTERATION OF URINARY SPECIFIC ACTIVITY.

SummaryUtilizing ureteral occlusion during low urine flow and the stop-flow technique during mannitol diureses it was noted that the calcium specific activity in the urine fractions obtained upon release of the ureteral clamp was altered in a manner which could be predicted from the state of kidney tissue calcium. It was concluded that the prolonged contact of the luminal fluid with the tubular epithelium when caused by a decrease in glomerular filtration rate resulting either from administration of massive doses of adrenergic drugs or from mechanical obstruction of urine flow, had provided time for a discernible addition of calcium from the epithelial cells to the tubular urine. Calcium concentrations in the stop-flow samples showed that addition of cellular calcium to the luminal fluid did not imply an active or net secretion.

TRIAMTERENE ACTIVITY INVESTIGATED BY THE STOP-FLOW TECHNIQUE AND IN VITRO STUDIES ON CARBONIC ANHYDRASE.

Acta Pharmacologica et ToxicologicaVolume 20, Issue 4 p. 351-356 Triamterene Activity Investigated by the Stop-Flow Technique and In Vitro Studies on Carbonic Anhydrase Ole E. Nielsen, Ole E. Nielsen Biological Department, Ferrosan Ltd., CopenhagenSearch for more papers by this authorJ. Buus Lassen, J. Buus Lassen Biological Department, Ferrosan Ltd., CopenhagenSearch for more papers by this author Ole E. Nielsen, Ole E. Nielsen Biological Department, Ferrosan Ltd., CopenhagenSearch for more papers by this authorJ. Buus Lassen, J. Buus Lassen Biological Department, Ferrosan Ltd., CopenhagenSearch for more papers by this author First published: February 1964 https://doi.org/10.1111/j.1600-0773.1964.tb01756.xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume20, Issue4February 1964Pages 351-356 RelatedInformation

STUDY OF PHOSPHATE EXCRETION BY THE STOP-FLOW TECHNIQUE. EFFECTS OF PARATHYROID HORMONE.

The stop-flow technique has been applied to the dog in an attempt to rule out tubular secretion of phosphate and to locate the site of action of parathyroid hormone (P.T.H.) on the renal tubule. Under the experimental conditions used, no significant inward transtubular movement of P32 could be demonstrated, ruling out tubular secretion of phosphate. Stop-flow experiments performed in parathyroidectomized dogs before and after P.T.H. administration demonstrated inhibition of phosphorus reabsorption by the hormone. In addition, the stop-flow pattern indicated that this phenomenon took place mainly in the distal part of the proximal tubules.

The Effect of Renal Perfusion Pressure on the Net Transport of Sodium Out of Distal Tubular Urine As Studied with the Stop-Flow Technique*

The Effect of Renal Perfusion Pressure on the Net Transport of Sodium Out of Distal Tubular Urine As Studied with the Stop-Flow Technique*

SITE OF REABSORPTION OF CITRATE AND CALCIUM IN THE RENAL TUBULE OF THE DOG.

Simultaneous reabsorptive patterns of calcium, citrate, sodium, potassium, creatinine, and para-aminohippurate (PAH) were determined by stop-flow technique during the infusion of calcium chloride and the neutral sodium salts of malate, citrate, and ethylenediaminetetraacetate (EDTA). Citrate reabsorption during citrate infusion occurred in the proximal nephron, coinciding with the area of PAH secretion while the calcium reabsorptive minimum was in the distal tubule, coinciding with the pattern of sodium reabsorption. Malate infusion abolishes citrate reabsorption, stimulates the distal secretion of potassium and, despite the marked increase in citrate excretion, fails to increase citrate concentration in renal tissue samples. EDTA infusion obliterates the calcium reabsorption minimum without affecting the more proximal pattern of citrate reabsorption. It is concluded that maximum citrate reabsorption occurs in the proximal region of the nephron distinctly separate from the more distal region of maximum calcium reabsorption.

STOP-FLOW ANALYSES OF MEPIPERPHENIDOL AND MECAMYLAMINE IN THE DOG.

The renal tubular excretion of mepiperphenidol was studied in dogs utilizing the stop-flow technique. Secretion of mepiperphenidol was shown to be localized in the proximal part of the nephron. The tubular excretion of mecamylamine was studied by this technique during acidification and alkalinization of the urine. Secretion of mecamylamine was shown to occur in the proximal area of the nephron irrespective of the urinary pH. The distal area of the tubule was shown to be the site of reabsorption of the base when the urine was alkaline. It was also shown that the secretion and the reabsorption of mecamylamine can occur simultaneously in the separate areas of the nephron.

Renal Excretion of Bilirubin in the Common Duct Ligated Dog

Summary By the use of the renal stop flow technique in dogs with the common duct ligated, we have demonstrated that one of the mechanisms for the excretion of bilirubin by the kidney is an active excretion of conjugated bilirubin by the distal portion of the nephron, including the ascending loop of Henle, distal tubules, the collecting ducts.

Stop flow 法の臨床的応用の検討

In 1957 Malvin first described stop flow technique as one of investigative methods of renal physiology. Though many experimental information regarding this method appeared since then, there has been no description of stop flow pattern in human kidneys. The author applicated this technique in man and fundamental stop flow patterns of several substances in osmotic diuresis through intravenous loading of hypertonic glucose solution were investigated. Objects of the investigation were 12 cases, 7 males and 5 females.They were divided into 2 groups: in Group 1, the investigation was done on 6 kidneys during the course of urological surgery, namely ureterolithomy or nephropexy under spinal anesthesia according to the original technique of Malvin and in Group 2 it was done on 6 kidneys, utilizing endoscopic insertion of ure teral bag catheter.The results are as follows:1) There was no significant difference of stop flow patterns between Group 1 and Group 2, except that urine flows in the former were less than in the latter.2) The stop flow pattern of sodium resembled very much to that of chloride, showing uniform distal reabsorption.3) Acidification of urine was done in the relatively narrow portion of the most distal tubuli.4) Concentration of creatinine reached to the maximum at the distal portion, indicating an intensive water reabsorption.5) The pattern of PAH showed its secretion in the proximal segment of the nephron.6) The stop flow pattern of potassium did not show any definitive tendency, when the value was expressed by (u/pK)/(u/pCr.). Typical tubular secretion of potassium in the distal portion was verified only in 2 of 12 kidneys.These findings did not much differ from the findings ascertained in dogs, except that the stop flow pattern of potassium showed no difinitive tendency of tubular secretion.Posibility of clinical application of stop flow method was discussed.

Transcellular diffusion of non-electrolytes across the renal tubular epithelium.

The stop flow technique was used to investigate the permeability characteristics of the dog nephron to various C(14)-labeled non-electrolytes. 12 minutes after clamping the ureter, creatinine, PAH, and C(14) compound were injected intravenously. 2 minutes later, urine samples were collected. Urea and glycerol were able to enter the tubular urine along the entire nephron at rates which were commensurate with their molecular weights. No significant movement of larger molecules (D-arabinose, D-glucose, and mannitol) could be detected. However, after administration of twenty units of pitressin, D-arabinose was able to diffuse across the distal and proximal tubular epithelium.

Mechanism of renal potassium secretion studied by a modified stop-flow technique.

The distal K-secreting mechanism of the kidney was studied by the stop-flow technique. With the original technique, maximal K secretion was demonstrated in the first 3 ml collected after occlusion. In adjacent proximal samples K and Na declined to minimum values and then returned to free-flow values. To study the relation between K secretion and luminal Na concentration at the K secretory site, the technique was modified by collecting only 3 ml after the first occlusion and then reoccluding. This permitted urine containing maximum K concentration to escape and allowed fluid quite low in sodium to move down to the K secretory site. Samples collected following the second occlusion regularly failed to show any distal K peak. If 8 ml were collected between occlusions, the fluid containing the Na and K minima was also collected, and Na concentration once again was raised at the K secretory site. This resulted in peak K concentrations following the second occlusion that were indistinguishable from the first. These are the findings expected for a K-for-Na ion exchange mechanism for distal K secretion. Coincidence of Na and K minima may be explained on this basis.