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Biomedical subjects

B Finlayson

Publications and source records attributed to B Finlayson.

At least 73 records · Page 4Linked to original sources
PubMed1983

Bilateral nephrolithiasis: simultaneous operative management.

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.

Adult↗
PubMed1983

Marked azotemia and increase in serum creatinine: case report of an unusual feature of acute ureteral obstruction in a renal allograft recipient.

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.

Adult↗
PubMed1983

Stone matrix as proteins adsorbed on crystal surfaces: a microscopic study.

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.

Animals↗
PubMed1982

Water hardness and urinary stone disease.

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.

Calcium↗
PubMed1982

Experimental calcium oxalate nephrolithiasis in the rat. Role of the renal papilla.

Calcium oxalate nephrolithiasis in rats, induced by single intraperitoneal injection of sodium oxalate, is associated with pathologic changes in the renal papillary tip. Calcium oxalate crystals appear in the tubular lumens, in the intercellular spaces between epithelial cells, and attached to the tubular epithelial basal lamina. Unusual paracrystalline structures also develop in the distal tubule associated with the basal lamina. Speculations are made about the role of these structures. The epithelial changes are primarily necrotic and are similar to those described in experimental papillary necrosis. Complete morphologic recovery occurs in 1-2 weeks.

Animals↗
PubMed1981

Distribution of organic matrix in calcium oxalate renal calculi.

The quantity of protein and carbohydrate comprising the matrix of calcium oxalate monohydrate (COM) renal stones was found to decrease with distance from the surface of the stone. The average organic concentration of stones 3 to 30 mm in diameter ranged from 5.7% at the surface to 2.7% at the core. This concentration gradient suggests matrix involvement in a "growth front" on stone surfaces with migration of organic material from the "older" interior. The matrix distribution was not readily correlated with density variations or with the presence of hydroxyapatite or calcium oxalate dihydrate. Surface matrix concentrations were greater than amounts predicted by physical adsorption. Electron microscopy confirmed the presence of the organic-rich surface layer and also suggested that increase in stone size occurs predominantly by crystal growth with microcrystal aggregates as growth centers.

Amino Acids↗
PubMed1981

Crystal morphologies in whewellite stones: electron microscopy.

Both dried and freshly extracted samples of whewellite stones were examined by light, scanning, and transmission electron microscopy to determine the spatial distribution of the organic (matrix) and inorganic (crystal) phases. The crystalline phase was determined to occur in oriented clusters within which the crystals were stacked with their broad faces parallel. Phase contrast TEM imaging revealed gaps of the order of 100 A between all crystals, and the result of dark field TEM imaging showed that these gaps contain the amorphous phase. Thus, the indications are that the matrix is sandwiched between the crystals and may, therefore, be responsible for cohesion in these stones.

Calcium Oxalate↗
PubMed1981

Light and scanning electron microscopic studies of oxamide urolithiasis in rats.

The formation of urinary oxamide stones was induced in rats by feeding them oxamide mixed with powdered rat chow. The structure of these stones and the changes in the rat renal papillary structure following oxamide administration were studied using bright field and polarizing light microscopy as well as scanning electron microscopy. Oxamide appeared in the papillary collecting ducts, pelvis, ureters and urinary bladder of the rats in the form of yellow spherulitic units composed of dendritic crystals. Oxamide stones in turn were aggregates of these spherulites. Our results indicate the renal stone formation started with the crystallization of oxamide in the tubular lumina of the collecting ducts of the papillae. Crystal formation in the tubules was associated with epithelial necrosis. Some of the crystals became attached to injured epithelium, thus impeding urinary flow. The attachment of the crystals resulted in their retention in the renal tubules. These oxamide deposits then grew or aggregated to form stones. The formation of oxamide deposits in the ducts of Bellini resulted in dilatation, compression of the epithelium and destruction of the papillary urothelium. These factors resulted in the deformation of the papillary tip of the kidney.

Amino Acids↗
PubMed1980

The treatment of urinary stone disease.

Once a patient has been guided past any acute problems of pain, obstruction or urosepsis, the stone type has been identified, and all metabolic problems and dietary indiscretions have been revealed, the physician treating a stone patient is faced with the frequently more arduous problems of treating or preventing the patient's stone disease. Several generalizations can be made about the strategies requisite for successful management of the long-term problem, and the problem is discussed in this paper in general and in some detail.

Calcium Oxalate↗
PubMed1980

The effect of seed crystals on calcium oxalate nucleation.

Equimolar concentrations of calcium chloride and potassium oxalate were precipitated by a rapid mixing technique. The precipitated calcium oxalate particles were repeatedly counted at 15 min with a Coulter counter until reproducible total particle count and particle distribution curves were obtained. These values were compared with those found after the addition of various seed crystals and 10 per cent urine to the system. Calcium oxalate seed crystals markedly enhanced the nucleation rate of calcium oxalate (1), although only an estimated 16 per cent acted as effective nucleators. The addition of sodium acid urate crystals resulted in a small decrease in the number of calcium oxalate particles precipitated and fewer than 0.1 per cent of the crystals acted as effective nuclei. Seeds of agglomerated hydroxyapatite crystals also produced a small decrease in the number of calcium oxalate particles and fewer than 1 per cent of the seeds functioned as nucleators. The addition of 10 per cent urine to the system greatly increased the number of calcium oxalate particles produced although we are uncertain whether the urine provided effective nuclei or prevented particle aggregation. Our data indicate that, in a rapidly mixed system, neither sodium acid urate nor hydroxyapatite crystals are effective nucleators for the precipitation of calcium oxalate. The occurrence of epitaxial growth of calcium oxalate on these substances in urinary stones is therefore called into question.

Calcium Chloride↗
PubMed1980

Stability of the calcium dioxalate complex.

The stability constant of the calcium dioxalate complex Ca(C2O4)2(2-), was measured at 38 C by examining the solubility of [45CA]whewellite in solutions with various oxalate concentrations. The solubility data showed that when oxalate was present above 10 mM increasing the oxalate concentration caused an increase in the apparent solubility of whewellite. This phenomenon was analyzed in the context of ionic equilibrium equations, and the stability constant of the dioxalate complex was estimated by fitting the experimental data with a nonlinear least-squares program. The estimated thermodynamic stability constant of the calcium dioxalate complex is 17.32 +/- 1.1 M-1.

Calcium Oxalate↗
PubMed1980

A proposal for a standard reference artificial urine in in vitro urolithiasis experiments.

We propose that in vitro urolithiasis research that involves crystallization should include in each observation set measurements made in a standard reference artificial urine to facilitate comparison of work done in different laboratories and facilitate the rate of advance in urolithiasis research. We describe a general technique to construct artificial urine and apply it to the construction of the reference artificial urine that we propose.

Crystallization↗
PubMed1980

Changes in calcium oxalate crystal, morphology as a function of concentration.

Calcium oxalate solutions in a wide range of concentrations were prepared and allowed to precipitate to determine how alterations in the calcium-to-oxalate ratio and the relative calcium oxalate supersaturation affected crystal morphology. The crystals were examined optically and with X-ray diffraction and their morphology was found to be closely related to relative supersaturation. Calcium oxalate monohydrate was the predominant species at all concentrations in which calcium oxalate precipitate was found. Calcium oxalate dihydrate was found only at high concentrations of both calcium and oxalate and underwent transformation to the monohydrate within 24 hr. Calcium oxalate trihydrate was not detected in any sample.

Calcium Oxalate↗