Biomedical subjects
Publications and source records attributed to B Finlayson.
A case report of life-threatening hemorrhage from a congenital renal arteriovenous malformation during pregnancy is presented. The hyperdynamic circulatory state that exists during pregnancy may predispose to bleeding from vascular malformations. We review the classification and clinical presentation of renal arteriovenous malformations.
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Injuries caused by hydrochloric acid or Triton X 100 application to the rat bladder urothelium, and the effects on calcium oxalate crystal retention, were examined by light and scanning electron microscopy. Damage due to either compound resulted in desquamation of urothelial cells. The crystals appeared to be retained by a fibrillar material, some of which was identified as fibrin. Heparin treatment of injured urothelium was found to prevent crystal retention.
Dissolution of uric acid calculi was studied in vitro. Calculated rate constants were then applied to an in vivo situation. The time required for complete dissolution of a uric acid calculus in a patient on oral alkali therapy can be estimated. Sodium bicarbonate, acetylcysteine, [tris(hydroxymethyl)aminomethane] and [tris(hydroxymethyl)aminomethane]-E were tested for relative effectiveness in dissolving uric acid calculi in vitro. In patients who require irrigation for dissolution of uric acid calculi [tris(hydroxymethyl)-aminomethane] is the preferred agent.
Calcium oxalate retention was studied in non-stone-forming volunteers. All subjects were placed on a constant diet for 5 days. After the oral administration of 10 microCi of [14C]-oxalic acid, the pattern of urinary oxalate excretion was followed for 48 h. Each subject was then given 10 microCi of [14C]-oxalic acid mixed with sufficient sodium oxalate (7.5 mg/kg body weight) to induce calcium oxalate crystalluria. Urinary oxalate excretion was then recorded for 48 h. After the administration of labeled oxalic acid (without additional sodium oxalate), 76.6 +/- 5.9% of the total recovered dose was excreted by 4 h. When the labeled oxalic acid was mixed with a sodium oxalate load, 62.4 +/- 8.8% was excreted by 4 h (p less than 0.01). Induction of calcium oxalate crystalluria results in the retention of oxalate in the kidney. The degree of retention varies among individuals. Differences in particle retention may help explain the differences between stone formers and non-stone formers.
The retrograde percutaneous nephrostomy, a new technique for access to the urinary tract for stone removal, involves cystoscopic placement of a 9 French catheter into a selected minor calix, through which a sheathed 20- or 21-gauge needle is then advanced to exit at the skin. The tract is then dilated over this needle. This technique has been used successfully in 38 patients with only three complications. The technique is more reliable and less time-consuming than the standard antegrade percutaneous approach, particularly in the nondilated pelvicaliceal system. However, to avoid damage to the liver, spleen, or pleural cavity, care must be taken to ensure that the needle does not exit in a cranial direction.
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We have compiled a broad overview of the genesis of urinary stones. Central to the theses given are precise definitions of stone as opposed to stone disease. In terms of mechanisms, a kinetic point of view is essential to any formulation relating to stone formation. It is necessary to comprehend the kinetic approach, an understanding of nucleation, growth and aggregation, if one is to appreciate the final product--the stone. Certain fundamental concepts are reviewed which are critical in grasping these phenomena. Not to be forgotten is that the purely physical chemical aspects of stone formation are insufficient to explain all facets of the process. Therefore, interactions between crystals and tissue are explored in suggesting a unifying hypothesis for upper tract stone disease.
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Crystalluria was induced in male Sprague-Dawley rats by implanting potassium-oxalate-containing mini-osmotic pumps. Urine of all experimental animals had abundant crystals of calcium oxalate, hydroxypatite, struvite, and calcium phosphate. These crystals were similar in morphology to the crystals found in human crystalluria. Histological examination of kidneys and tissue samples from other organs revealed no abnormality. One group of animals was injected with sodium oxalate in addition to implantation of potassium-oxalate-containing mini-osmotic pumps. Bladder urine from these animals contained calcium oxalate microstones and their kidneys had deposits of calcium oxalate crystals.
Successful stone manipulation was facilitated with the new monofilament basket in experimental situations and in patients. Advantages over other baskets include: in vivo adjustability, reduced mucosal trauma, ability to irrigate and aspirate through the basket, and ability to pass lithotriptor electrodes within the basket. Basket modifications under study might prove useful within the ureter, renal pelvis, and biliary tree.
Retrograde nephrostomy, a new technique to aid in stone management, has been performed successfully in dogs. It has also been used without complication in a human patient to help remove a renal stone percutaneously under local anesthesia. The technique consists of placing a coaxial catheter over a guidewire under fluoroscopy into the exact calyx desired and advancing a long needle out to the skin to establish a transcutaneous tract. The advantages of the technique include increased control and precision of tract placement, efficient working angles for percutaneous stone removal, and the ability to perform the procedure under local anesthesia.
A procedure for studying urinary stones by various microscopic techniques is described. The stones are sectioned into approximately 0.2 to 1.0 mm. thick pieces using a low-speed saw. The sections are then embedded in agar and decalcified using 0.25 M ethylenediaminetetracetic acid at pH 7.2. The decalcified residue is then processed for light microscopy and scanning and transmission electron microscopy as with any other biological tissue. The results indicate that the ethylenediaminetetracetic acid-insoluble stone matrix keeps its architectural integrity and can be studied like other biological materials.
A total of 14 patients with extensive bilateral nephrolithiasis underwent simultaneous bilateral lithotomy, in most instances through a single transabdominal incision. Anatrophic nephrolithotomy was performed on 25 kidneys, while 3 kidneys were approached in other ways without formal hypothermia and ischemia. There was no statistically significant change in the average preoperative and postoperative serum creatinine values (p greater than 0.1). There were residual stone fragments in 2 of the 28 kidneys (7 per cent) and stones recurred in 3 others (11 per cent) during the followup period (average 12 months). Of the 14 patients 10 (71 per cent) had infected urine preoperatively and 9 (64 per cent) have been free of infection postoperatively. There were no operative deaths and the average postoperative hospital stay was 17.6 days. We herein demonstrate that bilateral renal surgery for stone removal in 1 operative session can be performed safely with results comparable to those of unilateral staged procedures using other approaches. The advantages of this type of surgical management are discussed.
A patient is described who presented with late ureteral necrosis following renal transplantation, a complication that usually is seen in the early perioperative period. The patient was anuric with azotemia and a high serum creatinine. Response to surgical correction of ureteral obstruction was excellent and renal function returned to normal within 6 days postoperatively.
All urinary concretions are composed of a crystalline or mineral phase and a non-crystalline phase. Both phases vary markedly in their chemical nature. There are a number of theories about the role and morphogenesis of the organic phase or matrix. In our opinion, at least a part of the matrix is formed by adsorption of urinary proteins onto crystal surfaces. It has already been shown that naturally occurring polymers have an affinity for calcium oxalate crystal surfaces and that spaces filled with amorphous substances exist between calcium oxalate monohydrate crystals of whewellite renal stones. We wanted to visualize these crystal surfaces with adsorbed organic material. We studied calcium oxalate monohydrate crystals from urinary stones, and crystal made in a crystallizer and incubated in gamma globulin or bovine serum albumin. We also studied calcium oxalate monohydrate crystals experimentally induced in rat renal tubules. They were studied using light, scanning and transmission electron microscopy with, as well as without, EDTA digestion. All crystals were surrounded by an amorphous coat which may have originated by adsorption of proteins on crystal surfaces.
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On the macrogeographic scale, a strong negative association exists in the United States between water hardness and urinary stone disease. This investigation studies the association on the microgeographical scale, where it is possible to control for confounding environmental factors. The study was conducted on 2,295 patients from 2 regions: the Carolinas which had soft water and high stone incidence, and the Rockies which had hard water and low stone incidence. Home tap water samples from urinary stone patient hospitalizations were compared with that of controls, concurrent inguinal hernia patient hospitalization. After adjusting for environmental factors, no significant difference (p = 0.59) between the 2 groups was obtained in tap water calcium, magnesium, and sodium concentrations. An incidental but potentially important finding was that those consuming water from a private well had an estimated relative risk of 1.5 (p less than 0.01) compared to those using public water. While no cause-effect relationship is suggested, stone-formers might consider avoiding private well water. On the other hand, water hardness should be a minor concern with respect to stone formation.