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Biomedical subjects

L B Talner

Publications and source records attributed to L B Talner.

97 records · Page 6Linked to original sources
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Why does kidney size change during I.V. urography?

Meglumine iothalamate (280 ml I/ml) and sodium iothalamate (400 mg I/ml) in doses of 700 mg I/kg bw, were injected i.v. as a bolus in dogs. Renal size, urine flow rate, arterial pressure, renal blood flow and mean transit time and renal blood volume were measured before and after injection. All changes were qualitatively and quantitatively identical for both drugs. They produced a small transient renal shrinkage followed by a greater and prolonged renal enlargement. During the period of renal enlargement, urine flow increased. The time course of the enlargement paralleled the increase of urine flow rate. Renal blood flow also increased but both the mean transit time and renal vascular volume decreased. Therefore, the kidney size increase after i.v. injection of large doses of urographic contrast media cannot be attributed to an increased volume of the vessels. Most likely it is caused by diuresis-induced increase in the volume of the tubules.

Animals↗
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Renal vein renin activity in primary hypertension: variability and influence of contrast material.

Despite recognized limitations, the renal vein renin ratio (RVRR) remains the most commonly used index of surgical curability in hypertensive patients with renal artery stenosis. It is generally held that a ratio exceeding 1.5 forecasts a favorable response to surgery. Measurement of this ratio in 40 patients with essential hypertension (no arteriographically demonstrated stenosis) showed 8 (20%) with RVRR over 1.5, confirming an overlap of this ratio between patients with essential and renovascular hypertension. Intra-arterial injection of contrast material influenced renal vein renin activity (RVRA) in some individuals, but we were unable to demonstrate significant alterations in the group as a whole. Since the influence of intra-arterial contrast material on RVRA is variable and unpredictable, it appears unwise to collect renal venous blood for renin measurements soon after angiography.

Adult↗
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Intrarenal backflow during retrograde pyelography with graded intrapelvic pressure. A radiologic study.

Intrarenal backflow (IRB)--a form of pyelorenal backflow where contrast material appears in the renal parenchyma during retrograde pyelography--seems to be the same phenomenon as intrarenal reflux (IRR), sometimes observed during micturating cystography in children or animals with vesicoureteral reflux. Retrograde pyelography experiments were performed on baby pigs to study the relationship between renal pelvic pressure and IRB. Intrapelvic pressure was raised to 30-35 mm Hg (moderate) or 70-75 mm Hg (high) for 5 minutes. IRB developed in only four of 12 kidneys at moderate pressure but in all six kidneys at high pressure. Similar experiments were conducted on kidneys which had been rendered temporarily ischemic prior to retrograde pyelography. Twenty-seven kidneys were so studied 30 minutes after a 30- or 60-minute period of ischemia. With moderate and high pressure retrograde pyelography, all kidneys developed IRB. The most intense and widespread IRB occurred after 60 minutes of ischemia and at high pressure. IRB localized to the upper pole most frequently but was also observed in other portions of the kidney. The effect of IRB upon renal blood flow (RBF) was determined with electromagnetic flow probes during the same experiments. IRB caused a 16% mean decrease in RBF at moderate pressures and a 57% mean decrease in RBF at high pressures and was independent of preceding ischemia. It is concluded that both raised intrapelvic pressure and preceding renal ischemia are important factors determining the degree of IRB during retrograde pyelography and that backflow itself causes decreased RBF.

Animals↗
PubMedDate not supplied

Renal arteriography. The choice of contrast material.

Angiographers responding to a questionnaire disagreed on the agent of choice for selective renal arteriography. Opinion differed regarding the advantages of sodium versus meglumine salts, diatrizoate versus iothalamate, and 50-60 percent concentration agents versus those in the 70-76 percent range. Although an increasing number of angiographers are using more concentrated agents for renal arteriography, there is little information available to indicate their safety for this purpose. Dog experiments were done to see whether Renografin 76 percent (R-76), at a reasonable dose, caused more severe changes than the lower concentration agents. The studies failed to demonstrate significant differences between R-76 and the less concentrated agents indicating that R-76 can be used for selective renal arteriography if the additional iodine is deemed necessary. Factors affecting nephrotoxicity of contrast media in patients with normal and abnormal kidneys are discussed.

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