Evaluation of Tc-99m-DTPA for renal clearance studies in the pig

Worthley, C. S.; Byrne, Michael; Hickman, Rosemary

doi:10.1007/bf00280028

Cited by 3 publications

(4 citation statements)

References 14 publications

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“…In experiments using 24 Na, an extracellular marker easily detectable in muscle biopsies ( 99 Tc‐DTPA) was used. DTPA is a good marker because it has relatively low (∼10%) binding to proteins (Rehling et al ., 2001) and does not readily penetrate the intracellular fluids (less than 5% (Worthley et al ., 1988)). Using labelled DTPA enables a reasonably accurate calculation of the amount of 24 Na present within the intracellular fluid fraction of muscle biopsies.…”

Section: Discussionmentioning

confidence: 99%

“…The 99 Tc‐DTPA and 24 Na activities of each biopsy were measured, with decay and spillover correction. Less than 5% of the DTPA moves into the intracellular compartment over an extended period (Worthley et al ., 1988). The measurement of plasma 99 Tc‐DTPA activity was used to determine the extracellular volume of each muscle biopsy (ECF muscle ):

\begin{matrix} true \\ right EC F_{muscle} ((), ml / normalg) & = & left ({}, ^{99} normalT c_{muscle} ((), dpm / normalg)) / \\ left \times^{99} normalT c_{plasma} ((), dpm / ml), \end{matrix}

where 99 Tc plasma is the activity of 99 Tc in plasma at that time point.…”

Section: Methodsmentioning

confidence: 99%

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Pre‐loading large volume oral electrolytes: tracing fluid and ion fluxes in horses during rest, exercise and recovery

Waller

Lindinger

2021

The Journal of Physiology

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Key points Exercise results in rapid and large extracellular to intracellular fluid shifts, as well as significant sweating losses of water and ions. It is unknown whether ions within oral electrolyte supplements are taken up by muscle (and other soft tissues) and whether oral supplementation can effectively offset sweating losses. Pre‐loading with 8 L of a balanced hypotonic electrolyte supplement attenuated extracellular fluid losses, increased exercise duration and increased sweating fluid and ion losses during submaximal exercise. Supplemented electrolytes appear in skeletal muscle within 1 h after administration. Electrolyte supplementation increased exercise performance, improved maintenance of extracellular fluid volumes, and attenuated body fluid losses while maintaining sweating rates. Abstract This study used radioactive sodium (24Na) and potassium (42K) in a balanced, hypotonic electrolyte supplement to trace their appearance in skeletal muscle, and also quantified extracellular and whole‐body fluid and ion changes during electrolyte supplementation, exercise and recovery. In a randomized crossover design, 1 h after administration of 1 to 3 L of water or electrolyte supplement with 24Na, horses were exercised at 35% VO2max to voluntary fatigue or, after administration of 8 L of water or electrolyte supplement with 42K were exercised at 50% peak VO2 for 45 min (n = 4 in each trial). Pre‐exercise electrolyte supplementation was associated with decreased loss of fluid and electrolytes from the extracellular fluid compartments during exercise and recovery compared with water alone. The improved fluid and ion balance during prolonged exercise was associated with increased exercise duration, despite continuing sweating losses of fluid and ions. Nasogastric administration of radiotracer 24Na+ and 42K+ showed rapid absorption into the blood with plasma levels peaking 45 min after administration, followed by distribution into the extracellular space and intracellular fluid of muscle within 1 h. Following exercise, virtually all Na+ remained within the extracellular compartment, while the majority of K+ underwent intracellular uptake by 2 h of recovery. It is concluded that pre‐loading with a large volume, balanced electrolyte supplement helps maintain whole‐body fluid and ion balance and support muscle function during periods of prolonged sweat ion losses.

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Section: Discussionmentioning

confidence: 99%

\begin{matrix} true \\ right EC F_{muscle} ((), ml / normalg) & = & left ({}, ^{99} normalT c_{muscle} ((), dpm / normalg)) / \\ left \times^{99} normalT c_{plasma} ((), dpm / ml), \end{matrix}

where 99 Tc plasma is the activity of 99 Tc in plasma at that time point.…”

Section: Methodsmentioning

confidence: 99%

Pre‐loading large volume oral electrolytes: tracing fluid and ion fluxes in horses during rest, exercise and recovery

Waller

Lindinger

2021

The Journal of Physiology

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“…Four weeks after unilateral nephrectomy at the age of 10 months there was a pronounced increase in GFR and, in particular, ERPF in previously irradiated kidneys with no function (> 8.8 Gy) [14]. Worthley et al [22] conducted 19 pairs of GFR estimations in 10 pigs: 7 in normal pigs and 12 following bile duct ligation and/or nephrectomy, finding that absolute and weight-normalized endogenous creatinine clearances correlated significantly with 99mTc-DTPA elimination. Hagemann et al [4] performed unilateral nephrectomy in 109 male Wistar rats, with 35 animals as controls.…”

Section: Introductionmentioning

confidence: 99%

Renal function remains after unilateral total and contralateral partial nephrectomy: an experimental study in pigs using 99mTc-DTPA

et al. 1996

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Twelve nephrectomies (NEs) were performed in 12 pigs (11-17 kg). Total NE was performed on the left side and partial NE on the right side (lower third of the kidney), thus two-thirds of the total kidney volume was removed. Renal function was studied with 99mTc-diethylenetriaminepentaacetic acid (DTPA) renography and serum urea and creatinine levels preoperatively, and 1 and 2 weeks postoperatively. The pigs were imaged in each session for 30 min by collecting 10-s frames from a posteroanterior (PA) view of an anaesthesized animal. The injected activity was 37 MBq. Serial blood samples were taken from the subclavian vein at 0, 1, 2, 3, 5, 15, 25, 40, 60 and 120 min (six animals) after 99mTc-DTPA injection. The DTPA disappearance rate (DDR) was determined from these samples and in other cases (six animals) a blood sample at 20 min was used. The DDR was also determined from the dynamic gamma imaging data: Regions of interest (ROI) were upper body, spleen, heart and kidneys. The ROI analysis correlated well with the blood sampling data (r = 0.97, P < 0.0001). The reference values for pig DDRs were 0.99 +/- 0.08%/min. These values were 0.71 +/- 0.08%/min at 1 week postoperatively and 0.63 +/- 0.08%/min at 2 weeks. DTPA clearance rates were preoperatively 0.53 +/- 0.06 ml/s; at 1 week postoperatively 0.41 +/- 0.06 ml/s; and at 2 weeks 0.35 +/- 0.06 ml/s. There were no significant differences pre- and postoperatively in creatinine and urea concentrations. The DTPA clearance (ml/s) and disappearance rates (%/min) when determined per kidney area (cm2) increased significantly (P < 0.001 at both 1 and 2 weeks); in 11 of 12 animals the function of the resected right kidney was higher than the split function of the whole right kidney preoperatively. Unilateral nephrectomy initiates a functional adaptation or a growth response in the contralateral kidney to compensate for the loss of a renal mass. These data also indicate that two-thirds of the kidney volume in young pigs can be removed without danger.

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“…Until this study was conducted, only little information was available on the use of 99 m TC-DPTA as a radiotracer to measure single-kidney GFR in pigs. Most of the previous studies in this field described other methods and radiotracers for measuring total GFR in pigs or another big animal like dogs [122][123][124][125]. The only previous model for measuring single-kidney GFR deployed MRI contrast enhancement and was tested only in dogs, and it was technically difficult to conduct [123].…”

Section: Study Twomentioning

confidence: 99%

New Pharmacological Treatment to Preserve/Improve Renal Function After Partial Nephrectomy

Brignone

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Evaluation of Tc-99m-DTPA for renal clearance studies in the pig

Cited by 3 publications

References 14 publications

Pre‐loading large volume oral electrolytes: tracing fluid and ion fluxes in horses during rest, exercise and recovery

Pre‐loading large volume oral electrolytes: tracing fluid and ion fluxes in horses during rest, exercise and recovery

Renal function remains after unilateral total and contralateral partial nephrectomy: an experimental study in pigs using 99mTc-DTPA

New Pharmacological Treatment to Preserve/Improve Renal Function After Partial Nephrectomy

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