Arthur H. Jeske

Extraction of glutathione by the isolated perfused rabbit kidney

Abstract The effects of adding exogenous reduced glutathione (GSH) to the perfusate were studied in the isolated perfused rabbit kidney. The addition of 500 mg/liter of GSH to the perfusate prevented the depletion of cortical and medullary GSH; perfusion without the addition of GSH consistently resulted in depletion of tissue levels of this tripeptide. In addition, GSH supplementation of the perfusate decreased renal vascular resistance and increased perfusate flow. GSH extraction studies revealed a progressive decrease in renal extraction with time, ranging from complete extraction at 10 min to a value of 38% at 60 min. The fractional clearance of GSH increased from 7.3% at 10 min to 17.9% after 60 min of perfusion. The results indicate a high affinity of the rabbit kidney for GSH and a relatively large net reabsorption of the tripeptide.

Functional preservation of the mammalian kidney. III. Ultrastructural effects of perfusion with dimethylsulfoxide (DMSO).

Abstract Isolated rabbit kidneys were perfused at 37 ° C with a cell-free solution containing 0.0, 1.4, 2.1, and 2.8 m DMSO for 60 min. Electron microscopic examination of cortical structures revealed relatively high sensitivity of proximal tubular cells to DMSO-induced alterations, which included cytoplasmic clarification and disruption of microvilli. Glomeruli exhibited proliferation of rough endoplasmic reticulum, but were otherwise well preserved after perfusion with and without DMSO. Vascular endothelial cells were also intact after perfusion with DMSO, suggesting that DMSO-induced resistance changes are not necessarily associated with degeneration of capillary cells. Perfusion without DMSO resulted in good preservation of all cortical structures. These studies suggest that ultrastructural effects of DMSO must be considered in assessment of damage done in whole kidneys during freeze-preservation studies.

Functional preservation of the mammalian kidney. I. Normothermia, low-flow perfusion.

Isolated rabbit kidneys were perfused at normothermia and at low flow rates with perfusates of various compositions. K+- and Mg2+-rich perfusates appeared to ameliorate loss of renal function encountered with salt solutions of extracellular composition (Tyrodes). A vascular mechanism for the initial vasoconstriction observed during renal perfusion is suggested, and addition of isoxsuprine, a beta-adrenergic agonist, blocked the initial vasoconstriction. Normothermic, low-flow perfusion is able to maintain functional viability of the rabbit kidney for periods up to 90 min, after which some deterioration of function is noted. Na and K reabsorption, creatinine clearance, oxygen consumption, and urine acidification are, furthermore, observable in the isolated, normothermically perfused rabbit kidney at low flows. Normothermic perfusion for periods up to 90 min is a suitable means of administering cryoprotectant drugs in preparing whole kidneys for freezing studies.

Design, development, and performance of an electromagnetic illumination system for thawing cryopreserved kidneys of rabbits and dogs

Abstract Kidneys from rabbits and dogs were perfused with one of several DMSO concentrations (0.0, 0.7, 1.4, 2.1 m ) in a K + -Mg 2+ -rich perfusate, frozen, and then thawed with equipment providing electromagnetic (EM) illumination. Electrical properties (dielectric constant and loss tangent) of kidneys were measured both before and after EM thawing. The kidneys thawed were evaluated by simple anatomical (macroscopic and microscopic) and physiological observations rather than by transplantation. Rabbit kidneys which are no thicker than 2 cm could be optimally (uniformly and rapidly) thawed by use of illumination at 2450 MHz, a frequency which has a penetration depth of 2.1 cm at 0 °C, Optimal thawing of canine kidneys, which are twice as thick as rabbit kidneys, required the insertion of steel spheres (electroseeds) into the renal pelvis prior to freezing and illumination at 7 MHz in addition to that at 2450 MHz. Increasing the DMSO concentration (0.0 to 2.1 m ) in renal tissue illuminated with 2450 MHz increased the conductivity and the permittivity regardless of whether the renal tissue was frozen or thawed. The use of DMSO decreased the time for thawing with EM illumination and yielded kidneys with improved post-thaw morphology.

Comparative efficacy of 2 topical anesthetics for the placement of orthodontic temporary anchorage devices.

This study compared the effectiveness of topical benzocaine 20% versus a combination of lidocaine, tetracaine, and phenylephrine in providing sufficient analgesia for the placement of orthodontic temporary anchorage devices (TADs). The 2 topical anesthetics were tested against each other bilaterally using a randomized, double-blind, crossover design. The agents were left in place for the amount of time prescribed by the manufacturer. The TAD was then placed, and each subject rated the degree of pain on a Heft-Parker visual analogue scale. A pulse oximeter was used to record the preoperative and postoperative pulse rates. Statistically significant differences in perceived pain (P < .05) and success rate (P < .01) between drugs were seen, but no significant difference in pulse rate change between the topical anesthetics was observed (P > .05). It was concluded that when the efficacy of topical benzocaine and of a combination product was compared as the sole anesthetic to facilitate acceptable pain control for placement of orthodontic temporary anchorage devices, the combination product was considerably more efficacious.

Functional preservation of the mammalian kidney. IV. Functional effects of perfusion with dimethyl sulfoxide (DMSO) at normothermia

Rabbit kidney were perfused at 37degreesC with various concentrations of DMSO in a K+-Mg2+-rich perfusate. The effects of DMSO on various functional parameters of the rabbit kidney perfused for 60 min were compared with the functional effects of perfusion without DMSO under the same conditions. DMSO produced deviations in vascular resistance and perfusate flow rate from control values. In kidneys perfused with 1.4 and 2.8 M DMSO these vascular changes resulted in changes in GFR at relatively unchanged filtration fractions. The closely parallel relationship between changes in GFR and urine flow in all groups indicates that perfusion per se or perfusion with DMSO may shift the regulation of urine flow rate from tubular reabsorption, which obtains in the in vivo situation, to glomerular filtration. This view was supported by the relatively unchanged parameters of Na+ reabsorption and fractional water excretion during perfusion with all concentrations of DMSO. Additionally, DMSO perfusion resulted in significantly greater weight gains than those observed in kidneys perfused without DMSO, and significantly depressed clearances of PAH, with 2.1 and 2.8 M DMSO.

γ-glutamyl transpeptidase in the urine from an isolated rabbit kidney perfused with and without DMSO

Abstract γ-Glutamyl transpeptidase activity has been determined in the urine from isolated perfused rabbit kidneys. Kidneys were perfused for 60 min at 37 with a cell-free salt solution, and with the same solution containing 1.4, 2.1 or 2.8 M dimethylsulfoxide (DMSO). The enzyme is relatively stable when stored at 4° or at −20°, and the addition of DMSO to urine samples had no appreciable effect on enzyme stability. Analysis of urinary γ-glutamyl transpeptidase activity demonstrated timedependent release of this enzyme by the isolated rabbit kidney perfused with the cell-free salt solution. The addition of 1.4 and 2.8 M DMSO to the solution led to significant increases in the level of transpeptidase found in the urine. There was no significant correlation between urinary enzyme levels and urine flow rates in the presence or absence of DMSO. This represents the first demonstration of a urinary form of this enzyme which is unequivocally derived from renal tissue. Unlike natural urine, the urine derived from perfused kidneys contains mostly particulate γ-glutamyl transpeptidase. The increase in particulate urinary transpeptidase and alkaline phosphatase levels with time. coupled with the significant increases in urinary transpeptidase activity during perfusion with cytotoxic levels of DMSO, suggests that pieces of renal brush border are being broken off and are appearing in the urine.

Development of an in vivo model for assessment of drug-induced vascular injury

Thrombophlebitis is a common complication associated with infusion of intravenous sedatives, especially diazepam. Development of a technique for evaluation of drug-induced histopathologic changes in animal tissues should allow for more precise study of methods and agents which might be used clinically to minimize the thrombophlebitic phenomena. In this study, the authors describe the use of the marginal ear vein of the rabbit as a model for studying drug-induced thrombophlebitis, as well as techniques for reducing or preventing it.

The effect of cold storage on the sensitivity to alpha and beta agonists in the isolated rabbit kidney

Rabbit kidneys were perfused at 25 degrees C, and the effect of alpha and beta agonists was studied, before and after 24 hr of cold storage. Vascular and in vitro functional parameters were evaluated. We concluded that cold storage impairs partially the vascular alpha receptor. We could not find beta receptors under these conditions. An electron microscope analysis of these kidneys has shown some degree of autolysis of the tubular cells and good preservation of the vascular smooth muscle cells and membranes. These results are very important for kidney preservation before transplantation.

Ultrastructure of canine renal autografts following 24 hour hypothermic preservation

29 canine kidneys were preserved for 24 h by hypothermic, pulsatile or nonpulsatile perfusion with albumin or cryoprecipitated plasma and were autotransplanted. Electron microscopy of biopsies taken a