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The Ess1/Pin1 peptidyl-prolyl isomerase (PPIase) is thought to control mitosis by binding to cell cycle regulatory proteins and altering their activity. Here we isolate temperature-sensitive ess1 mutants and identify six multicopy suppressors that rescue their mitotic-lethal phenotype. None are cell cycle regulators. Instead, five encode proteins involved in transcription that bind DNA, modify chromatin structure or are regulatory subunits of RNA polymerase II. A sixth suppressor, cyclophilin A, is a member of a distinct family of PPIases that are targets of immuno suppressive drugs. We show that the expression of some but not all genes is decreased in ess1 mutants, and that Ess1 interacts with the C-terminal domain (CTD) of RNA polymerase II in vitro and in vivo. The results forge a strong link between PPIases and the transcription machinery and suggest a new model for how Ess1/Pin1 controls mitosis. In this model, Ess1 binds and isomerizes the CTD of RNA polymerase II, thus altering its interaction with proteins required for transcription of essential cell cycle genes.

Purpose: Current studies have provided evidence that exposure of renal epithelial cells to oxalate and calcium oxalate crystals induces lipid peroxidation and injures the cells. Since oxidant/antioxidant balance is likely to play a critical role, we determined the effect of antioxidant scavengers on production of free radicals and injury to LLC-PK1 and MDCK cells from exposure to oxalate (Ox) or Ox + calcium oxalate monohydrate (COM) crystals., Materials and Methods: LLC-PK1 and MDCK cells were grown in monolayers and exposed to 1.0 mmol. Ox or 1.0 mmol. Ox + 500 microg. /ml. COM crystals for 120 or 240 minutes. We measured the release of lactate dehydrogenase (LDH) as a marker for cell injury and malondialdehyde (MDA) as a marker of lipid peroxidation. Superoxide and hydroxyl radicals were measured in the presence or absence of 400 U/ml. catalase, or superoxide dismutase (SOD)., Results: Exposure of LLC-PK1 cells to Ox resulted in a significant increase in MDA and release of LDH, which was further elevated when COM crystals were added. MDCK cells responded similarly to both challenges, but showed significantly less impact when compared with LLC-PK1 cells. Both treatments were associated with significant increase in the generation of hydroxyl and superoxide radicals by both cell types. In both cell lines, the addition of catalase or SOD significantly reduced the increase of MDA and release of LDH., Conclusions: Results of the present study indicate that both Ox and COM crystals are injurious to renal epithelial cells and the injury is associated with generation of free radicals. Cells of proximal tubular origin are more susceptible than those of distal tubules and collecting ducts. Free radical scavengers, catalase and SOD provide significant protection.

LLC-PK1 and Madin-Darby canine kidney (MDCK) cells were used to study the role of free radicals in renal epithelial injury during exposure to oxalate ions (Ox) and calcium oxalate monohydrate (COM) crystals. The cell cultures were exposed for 120 or 240 min to 1.0 mmol Ox or 1.0 mmol Ox plus 500 microg/ml of COM crystals averaging 1.0 microm in size. Exposure of both LLC-PK1 and MDCK cells to Ox alone increased the leakage of lactate dehydrogenase, which was further enhanced when cells were exposed to Ox + COM crystals. The release of lactate dehydrogenase from the LLC-PK1 cell line, however, was significantly higher than that from MDCK cells. LLC-PK1 cells also showed a significant increase in malondialdehyde (MDA) content on Ox challenge. MDA content was even higher when LLC-PK1 cells were challenged with Ox + COM crystals. However, in MDCK cells, the elevated MDA content was similar in both treatment groups, suggesting that these cells may be more resistant to the calcium oxalate crystals. Glutathione peroxidase activity was decreased in both LLC-PK1 and MDCK cells. Challenging cells with Ox + COM resulted in decreased catalase activity in LLC-PK1, but increased catalase activity in MDCK cells. Superoxide dismutase activity and reduced glutathione content were not significantly different in either cell type when challenged with Ox or Ox + COM. Previous in vivo animal studies yielded indirect evidence for the increased lipid peroxidation during hyperoxaluria-induced nephrolithiasis. However, in an animal model, it is difficult to separate the effect of Ox from Ox in combination with COM crystals. This study suggests that the injury to renal tubular epithelial cells is accompanied by lipid peroxidation when exposed to Ox. The injury is augmented when COM crystals are included. LLC-PK1 cells are more susceptible to Ox-associated injury than MDCK cells.

Two renal epithelial cell lines, LLC-PK1 and Madin-Darby canine kidney (MDCK), were grown in monolayers and exposed to oxalate (Ox) and/or calcium oxalate (CaOx) crystals to investigate cellular responses to these challenges. In addition, LLC-PK1 cells were exposed to high concentrations of Ox for various time periods to investigate the role of apoptosis in Ox-associated cell injury. Both cell types showed signs of damage when exposed to Ox. However, LLC-PK1 cells appeared more sensitive than MDCK cells. There was a significant increase in release of lactate dehydrogenase into the medium and decrease in trypan blue exclusion by cells in the monolayer. Most noticeable was the detachment of cells from the substrate. Exposure of cells to CaOx crystals resulted in their attachment to cell surfaces followed by internalization. Using flow cytometry for quantification of apoptotic cells, transmission electron microscopy for morphology, and electrophoresis for DNA laddering detection, we observed significant apoptotic changes including condensation and margination of nuclear chromatin, DNA fragmentation, and migration of phosphatidylserine of the plasma membrane from inside to the cell surface. However, these cells also showed some necrotic changes such as loss of plasma membrane integrity and release of lactate dehydrogenase, indicating that the apoptotic process was interrupted.

Purpose: To determine if lipid peroxidation plays a role in renal injury associated with experimental nephrolithiasis., Materials and Methods: Hyperoxaluria was produced in rats by ethylene glycol in drinking water. At 15, 30 and 60 days of treatment, urinary oxalate, lipid peroxide, calcium oxalate crystals, enzymes and tissue lipid peroxide were measured., Results: Urinary oxalate increased significantly at all time periods and was associated with crystalluria. Lipid peroxides in kidney tissue and urine increased at all time periods. Tissue calcium oxalate crystal deposits from 0 to 1+ were present on day 15, but present in all animals on days 30 and 60. Renal tubular cell damage was confirmed by an increase in urinary marker enzymes., Conclusions: Renal cell damage is associated with lipid peroxide production indicating cell injury due to the production of free radicals. The damage appears due primarily to hyperoxaluria and is augmented by crystal deposition in the renal tubules.

Mitomycin is used extensively for the prevention of recurrence of superficial bladder cancer. Most treatment regimens of mitomycin are long term, since this seems more effective in preventing recurrence. During treatment some patients develop cystitis of variable severity, which may lead to mucosal ulcerations and cessation of treatment. We report a case in which long-term treatment with mitomycin, following a single episode of transitional cell bladder cancer, has led to bladder fibrosis and loss of its function, without evidence of tumor recurrence.

We have sequenced the region of DNA adjacent to and including the flightless (fli) gene of Drosophila melanogaster and molecularly characterized four transcription units within it, which we have named tweety (twe), flightless (fli), dodo (dod), and penguin (pen). We have performed deletion and transgenic analysis to determine the consequences of the quadruple gene removal. Only the flightless gene is vital to the organism; the simultaneous absence of the other three allows the overriding majority of individuals to develop to adulthood and to fly normally. These gene deletion results are evaluated in the context of the redundancy and degeneracy inherent in many genetic networks. Our cDNA analyses and data-base searches reveal that the predicted dodo protein has homologs in other eukaryotes and that it is made up of two different domains. The first, designated WW, is involved in protein-protein interactions and is found in functionally diverse proteins including human dystrophin. The second is involved in accelerating protein folding and unfolding and is found in Escherichia coli in a new family of peptidylprolyl cis-trans isomerases (PPIases; EC 5.2.1.8). In eukaryotes, PPIases occur in the nucleus and the cytoplasm and can form stable associations with transcription factors, receptors, and kinases. Given this particular combination of domains, the dodo protein may well participate in a multisubunit complex involved in the folding and activation of signaling molecules. When we expressed the dodo gene product in Saccharomyces cerevisiae, it rescued the lethal phenotype of the ESS1 cell division gene.

We describe an operation that increases bladder neck resistance in patients with urinary incontinence. It is a modification of the rectus fascial sling that was designed as an adjunct to augmentation cystoplasty and is used in association with clean intermittent catheterization. The operation is performed by circumferentially wrapping a rectus fascial defatted free graft around the bladder neck and suturing it to appose the bladder neck. The procedure was done in 17 patients, including 10 with myelodysplasia, 3 with sacral lipoma, 3 with bladder exstrophy and 1 with nonneurogenic neurogenic bladder. Leak point pressure improved in patients in whom it was measured preoperatively and postoperatively. Complications developed in 5 patients, including difficulty with catheterization in 2, ventral hernia at the graft harvest site in 1, bladder calculus in 1 and detrusor hyperreflexia in 1. Early results with the bladder fascial wrap indicate that it has the ability to improve continence in patients with a dysfunctional bladder neck who have undergone augmentation.

Structural analysis of human kidney stones reveals the presence of cellular membranes and other cell fragments. Experimentally, calcium oxalate crystallization is facilitated when an exogenous nephrotoxin is given with ethylene glycol, thus providing cellular degradation products to act as heterogeneous nuclei. In this report, we tested whether oxalate alone could act as a cell toxin capable of producing damaged cells without the presence of an exogenous agent. Cultured LLC-PK1 and MDCK cells, when exposed to 1.0 mmol KOx, a concentration at the limit of metastability for calcium oxalate nucleation, were severely damaged as measured by specific lactate dehydrogenase (LDH) release in the spent media and by trypan blue exclusion. This effect was magnified by the addition of pre-formed calcium oxalate monohydrate crystals; the injury was significantly amplified when compared to exposure to oxalate alone. Scanning electron microscopy studies illustrated attachment of crystals to cells with loss of cell-to-cell and cell-to-substrate contact, as cells were released from the monolayer. In both oxalate and combined crystal-oxalate studies, more cells were released from the monolayer and exhibited considerably more damage when compared to controls. Oxalate, at the limit of metastability for calcium oxalate, is a cell toxin and can produce cellular degradation products. This effect is increased significantly by the addition of calcium oxalate monohydrate crystals.

Human calcium oxalate monohydrate (COM) urinary stones were decalcified by treatment with a mixture of ethylenediaminetetraacetic acid (EDTA) solution and Karnovsky's fixative after embedding in bactoagar. Decalcified stones were examined by light microscopy, and also by scanning and transmission electron microscopy. Stones had distinct nuclei that were occupied by amorphous or apatitic calcium phosphate or aggregates of spherulitic COM crystals. EDTA insoluble matrix was ubiquitous in stones and consisted largely of finely matted fibrous material. It was organized in concentric laminations in the peripheral area of the stone but appeared highly disorganized in the stone center. Crystals were replaced by crystal ghosts. Organic matrix was present both inside the crystals and in the intercrystalline spaces. The study indicates a very close association between crystals and organic matrix. The relationship appears to begin early in crystal formation and persists throughout the formative and growth phases of the urinary stones.

We studied the effect of oral administration of magnesium oxide (MgO) on calcium oxalate (CaOx) nephrolithiasis in rats. Nephrolithiasis was induced by administration of 1.0% ethylene glycol (EG) in drinking water. Magnesium oxide was given mixed with food at 500 mg./100 g. rat chow. Dispensation of MgO resulted in a significant increase of urinary pH and a modest increase in urinary excretion of citrate. Urinary excretion of oxalate started to decline by day 14 and was significantly reduced on days 21 and 28. All rats receiving EG displayed crystalluria. From the group receiving EG only, 3 of 4 rats sacrificed on day 15 and 2 of 4 rats sacrificed on day 29 had CaOx crystal deposits in their kidneys. None of the 8 rats who received both EG and MgO had CaOx nephrolithiasis. Thus our findings indicate that dispensation of magnesium as MgO can be beneficial against calcium oxalate nephrolithiasis.

Fresh whole prostate glands were examined systematically in a water bath to look for four sonographic criteria for prostatic carcinoma: well-circumscribed hypoechoic regions, external asymmetry of the gland, increase in anterior-posterior diameter ratio, and irregularity of the prostatic capsule. Whole mount sections were examined to correlate the histopathologic and sonographic findings. Using hypoechogenicity alone, 26 of 43 glands harboring tumor were identified correctly. Using all four criteria, 40 of 43 glands harboring tumor were identified, a statistically significant improvement in sensitivity (P less than 0.05). Specificity of both methods was similar (P greater than 0.1). The three tumors that were missed measured 0.5 x 0.5 x 0.5 cm, 0.5 x 0.5 x 0.5 cm, and 0.3 x 0.4 x 0.9 cm, and were found at autopsy in patients who died of causes unrelated to the prostate. The authors conclude that systematic examination of the gland with attention to multiple criteria for abnormality can improve case finding in prostatic adenocarcinoma.

Single intraperitoneal injections of three, seven, or 10 mg. of sodium oxalate per 100 gm. of rat body weight were administered to male Sprague-Dawley rats. At various times after the injection, urine samples were analyzed for oxalate, and urinary enzymes, alkaline phosphatase, leucine aminopeptidase, gamma-glutamyl transpeptidase, and N-acetyl-beta-glucosaminidase. The kidneys were processed for light microscopy and renal calcium and oxalate determination. Oxalate administration resulted in an increase in urinary oxalate and formation of calcium oxalate crystals in the kidneys. The amount and duration of urinary excretion of excess oxalate and retention of crystals in the kidneys correlated with the dose of sodium oxalate administered. At a low oxalate dose of three mg./100 gm., crystals moved rapidly down the nephron and cleared the kidneys. At higher doses crystals were retained in kidneys and at a dose of 10 mg./100 gm. were still there seven days post-injection. Crystal retention was associated with enhanced excretion of urinary enzymes indicating renal tubular epithelial injury.

Crystal retention within the renal tubules is essential for nephrolithiasis and the development of urinary stone disease. We studied the mechanisms involved in this process by inducing calcium oxalate crystal deposition within the rat renal tubules and examining them using various microscopic techniques. Crystals appeared to be retained either by attachment to the tubular epithelium or by aggregating with other crystals thus becoming large enough to be retained by their collective size.

Previous studies have shown that hypomagnesuria induced by magnesium deficient diet causes calcium oxalate crystal deposition in renal tubules of hyperoxaluric rats and administration of magnesium to these rats results in prevention of calcium oxalate crystallization in their kidneys. Based on these studies magnesium was claimed to be beneficial for calcium oxalate stone patients. However, hypomagnesuria is not a common phenomenon. To better understand the role of magnesium as an inhibitor of calcium oxalate crystallization in urine, we studied the effect of magnesium on calcium oxalate urolithiasis in rats on a regular diet and a hyperoxaluric protocol. Excess magnesium was administered to male rats on regular diet and a lithogenic protocol. Magnesium administration to hyperoxaluric rats did not result in significant changes in urinary excretion of calcium or oxalate or in calcium oxalate relative supersaturation. Urinary excretion of citrate was also not significantly altered. Some animals from both groups, those on magnesium therapy and those not on magnesium therapy had crystals deposited in their renal tubules. We conclude that excess magnesium has no significant effect on calcium oxalate urolithiasis in normomagnesuric conditions.

Various agents have been implicated in inducing urothelial cancer. Although drugs, occupational and environmental carcinogens are more widely accepted as playing a major role as urothelial carcinogens, several investigations suggest that bacteria may play a role. The mechanism of how bacteria may interact with the host to augment the development of urothelial carcinoma is not well understood. Clinically, investigators have linked the development of infection, urinary stones and indwelling catheters with urothelial cancer. Other investigators have suggested that the mechanism may be related to the production of carcinogenic compounds (nitrosamines) which can be detected during urinary tract infection. In our laboratory, we showed that rats with chronic urinary tract infections produced increasing urinary levels of N,N dimethylnitrosamine over a 24 week period and that the production correlated with hyperplasia and early neoplasia of the bladder epithelium. Three bacterial genera were used and two of these (Escherichia coli and a protein sp.) showed production of increasing levels of urinary nitrosamine and correlated with infection. The purpose of this current study is to determine if other bacterial genera and strains can also produce similar increasing nitrosamine levels in the rat model of chronic urinary tract infection and thus provide evidence that a number of bacterial genera and strains can produce nitrosamines in vivo. Also, the histology of the chronically infected bladder was examined for hyperplasia and neoplasia.

Renal tubular cell damage, resulting in membranuria, was induced by the administration of subcutaneous gentamicin to male Sprague-Dawley rats. One group of rats received gentamicin only, while a second group was given gentamicin plus ethylene glycol in drinking water at a concentration which increased urine oxalate but alone did not cause calcium oxalate crystalluria. Crystalluria occurred early in the combined treatment groups and persisted for the duration of the experiment. Crystalluria was not present in animals receiving gentamicin or ethylene glycol only. These results suggest that cellular fragments can serve as heterogeneous foci for the nucleation of calcium oxalate crystals.

Glutamine may be an essential dietary component, especially for the support of intestinal mucosal growth and function. This study evaluated the effects of a glutamine-enriched elemental diet, administered before whole-abdominal radiation on gut glutamine metabolism, mucosal morphometrics, and bacterial translocation. Rats were randomized to receive a nutritionally complete elemental diet that was glutamine-enriched or glutamine-free for 4 days. The animals were then subjected to a single dose of 1000 cGy x-radiation to the abdomen. After irradiation, all animals received the glutamine-free diet. Four days later the animals underwent laparotomy for sampling of arterial and portal venous blood, culture of mesenteric lymph nodes, and removal of the small intestine for microscopic examination. There was no difference in arterial glutamine or gut glutamine extraction between the two groups, but body weight loss was significantly diminished in the glutamine-fed rats. Rats receiving the glutamine-enriched elemental diet before radiation had a significant increase in jejunal villous number, villous height, and number of metaphase mitoses per crypt. Scanning electron microscopy confirmed the presence of an intact gut epithelium in eight of eight rats receiving prophylactic glutamine compared to one of eight animals in the glutamine-free group. Three of eight rats fed glutamine had culture positive mesenteric lymph nodes compared with five of seven rats receiving the glutamine-free diet. Glutamine exerts a protective effect on the small bowel mucosa by supporting crypt cell proliferation effect on accelerate healing of the acutely radiated bowel.

Incubation of proximal tubular brush border membrane in a metastable calcium oxalate solution of low supersaturation resulted in the equimolar depletion of calcium and oxalate and the formation of monoclinic calcium oxalate crystals. We propose that membrane fragments from sloughed epithelial cells of the nephron can similarly induce crystallization in urine that is metastable for calcium oxalate.

The eighth reported case of primary signet ring cell carcinoma of the urinary bladder is described clinically and pathologically. It is unusual because of complete replacement of the transitional epithelium by squamous and glandular metaplasia. The latter was particularly striking, demonstrating "normal" colonic mucosa, cystitis glandularis, well-differentiated adenocarcinoma, poorly differentiated adenocarcinoma, and the rare signet ring cell carcinoma variant. The possible origin of such changes is discussed.

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.

Fragments of urinary stones resulting from extracorporeal shock wave lithotripsy were examined by light and scanning electron microscopy. Calcium oxalate monohydrate and uric acid stone fragments were homogeneous and regular whereas struvite stone fragments were irregular in shape. Examination of the fractured surfaces revealed that the process of stone fragmentation involved fracture and cleavage of the crystals at some places and their separation from each other at others. In stones whose crystals are organised in layers, for instance calcium oxalate monohydrate and uric acid, crystalline layers separated along the concentric laminations. In struvite stones, which are an agglomeration of struvite and calcium phosphate crystals, major fragmentation occurred along the crystalline interfaces.

Human urinary stone fragments and sections were decalcified in ethylenediaminetetraacetic acid solution after embedding in 1% agar. These decalcified embedded stone specimens were then processed for scanning electron microscopy. After critical point drying the agar was removed and EDTA-insoluble stone residue was studied by scanning electron microscopy. This residue representing part of the stone matrix kept the original shape of the stone and was basically made of fibrous material. The fibers appeared to be arranged in matted sheets that were present as concentric laminations. In case of calcium oxalate dihydrate stones these fibrous sheets were also arranged as peripheral layers running parallel to the pyramidal faces of large calcium oxalate dihydrate crystals. In decalcified stones, crystals were represented by crystal ghosts. Often some vesicular material was present embedded in the fibrous sheets.

The presence of lipids in urinary stones was determined by histochemical and biochemical methods. When crystals of calcium oxalate, made by mixing calcium chloride and potassium oxalate solutions and sections of human calcium oxalate urinary stones, were exposed to osmium vapors, there was no staining of the pure crystals whereas the stone sections were stained. De-paraffinized sections of demineralized calcium oxalate stones showed positive sudanophilia on staining with Sudan black B. Both these experiments indicate the presence of lipids in calcium oxalate stones. Lipids were extracted from uric acid, struvite, and calcium oxalate stones using standard techniques. Phospholipids were separated by one-dimensional thin layer chromatography. All the stones studied contained lipids. In calcium oxalate stones they accounted for 10.15% of the matrix. Calcium oxalate and struvite stones contained more phospholipids than uric acid stones. Cardiolipin, sphingomyelin, phosphatidyl choline, phosphatidyl inositol, phosphatidyl ethanolamine, phosphatidyl serine, and phosphatidyl glycerol were identified in lipid extracts. Demineralization by ethylenediaminetetra-acetate (EDTA) treatment increased lipid output from calcium oxalate stones by 15.5%.

The formation of calcium oxalate crystals in rat kidneys was induced by intraperitoneal challenge with sodium oxalate. The structure of these crystals and the effect of their formation on the architecture of the tubular epithelium was studied by SEM. From the results we conclude that the crystals were formed intraluminally in the renal tubules. During the growth of the microliths they were closely adherent to the luminal surface of the tubular epithelial cells. Two types of the crystals were identified. Calcium oxalate monohydrate crystals consisted of plate-like crystallites and were more common. Dihydrate crystals on the other hand were tetragonal dipyramids and were less common. Elemental analysis of the crystal surface revealed them to be closely similar to the crystals present in calcium oxalate stones. The renal tubules were morphologically altered. Their epithelial cells underwent focal necrosis. There was a focal loss of the microvillous brush border of the proximal tubules. The epithelial cells formed large blebs which protruded into the tubular lumen. Sometimes the tubular lumen was completely occluded by the crystals. Crystals were often covered with cellular debris. It is suggested that the cellular debris derived from from necrotic cells become incorporated into the calculi. A similar process may be involved in the formation of mucoproteinaceus matrix of the human renal stones.

Sprague-Dawley rats were injected with known nephrotoxic doses of tobramycin and then subjected to varying amounts of warm renal ischemia. Analysis of serum creatinine at the time of sacrifice revealed no statistically significant difference among controls and the two doses of tobramycin at any given duration of ischemia. Light microscopy revealed no worsening of tubular necrosis with increasing doses of tobramycin.

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.

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.

Primary malignant melanoma of the male urethra is a rare disease, with only 24 cases previously reported in the literature, including 1 black patient. We describe 2 additional patients with primary malignant melanoma of the urethra, one of whom was a black man. The literature is reviewed briefly and treatment recommendations are discussed.

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.

Urinary crystals can be identified by using analytical electron microscopic techniques of scanning electron microscopy and energy dispersive x-ray microanalysis. Crystal habit can be recognised by scanning electron microscopy and their chemical nature by elemental analysis. With a conventional detector the lightest element that can routinely be detected is sodium, but with a windowless or thin window detector even carbon can be detected. Thus almost all the commonly occurring urinary crystals including uric acid can be analysed by energy dispersive x-ray microanalysis.

Experimental renal carcinoma was induced by percutaneous injection of VX-2 carcinoma cells into the left kidney in New Zealand white rabbits. Magnetic resonance imaging (MRI) was performed at 0.15 T before and after intravenous injection of 0.3 mmol gadolinium-DTPA (Gd-DTPA) per kg body weight. Gd-DTPA enhanced the tumors by increasing the signal intensity on T1 weighted images. The enhancement was evident immediately after Gd-DTPA injection, increasing during the observation time of 30 minutes. Histologically the areas of enhancement corresponded well to the viable tumor tissue.

Organic matrix of human calcium oxalate urinary stones was obtained by demineralizing with EDTA. Lipids were extracted from the EDTA-insoluble matrix by chloroform methanol treatment. The whole matrix and its total lipid extract were then incubated in a metastable solution of calcium oxalate and depletion of calcium and oxalate ions from the calcifying solution was determined. Results of our studies described here show that urinary calcium oxalate stone matrix and its total lipid contents were capable of binding calcium and oxalate ions and of catalysing calcium oxalate crystal formation from a metastable calcium oxalate solution.

Urine of male Sprague-Dawley rats was supersaturated for struvite and often contained struvite crystals. Ethylene glycol administration to these rats resulted in elevation of urinary oxalate and calcium oxalate supersaturation, and induced calcium oxalate crystalluria. Implantation of foreign bodies in their urinary bladders and changing their urinary ambient conditions by administering ethylene glycol for two weeks at two week intervals resulted in the formation of urinary stones of mixed composition containing calcium oxalate and struvite. Crystal-onto-crystal epitaxy did not appear to play any role in the development of these stones.

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.

Birefringent crystals of calcium oxalate have been previously identified in the colloid of human thyroid glands. We found such crystals in 19/20 adult thyroids at autopsy, in 4/20 infants at autopsy, and, using frozen sections, in 19/20 thyroids partially or totally removed at surgery. These crystals were soluble in hydrochloric acid, insoluble in acetic acid, and contained only calcium by energy dispersive X-ray microanalysis, confirming their calcium oxalate character. Similar crystals were found in equine and ovine thyroids.

Calcium oxalate bladder stones were induced in male rats by implanting plastic foreign bodies and by adding ethylene glycol to their drinking water. The foreign body surface was first coated with cellular debris and some amorphous material. Encrustation with crystals of calcium oxalate started on the third day of implantation. Within 2 weeks the entire surface of a foreign body was covered with crystals and some noncrystalline material. Calcium oxalate monohydrate crystals consisted of platelike crystallites arranged in hemispherulitic or spherulitic habit. Calcium oxalate dihydrate crystals wee basically dipyramidal, a majority of them showing interpenetrant twinning. The stone grew by confluent crystal growth and crystal aggregation. A transformation of calcium oxalate monohydrate crystals to calcium oxalate dihydrate also occurred. The matrix consisting of cellular debris and urinary macromolecules was universally distributed in the stone including the inside of crystal bodies.