Influence of urinary sialic acid on calcium oxalate crystal formation.

Using seed crystal method, whole-urine method, and scanning electron microscopy, the inhibitory effects of sialic acid and osteopontin (OPN) on aggregation/growth of CaOx crystals were investigated. Using the seed crystal method, sialic acid showed an inhibitory effect on CaOx crystal aggregation/growth in a concentration-dependent manner, but almost no effect was observed using the whole-urine method. OPN showed an inhibitory effect on aggregation/growth in both experimental systems. The inhibitory effect of asialo-OPN on aggregation/growth was approximately 20% lower than that of OPN in the experiment using the seed crystal method and approximately 15% lower in the experiment using the whole-urine method. Scanning electron microscopy showed that OPN and sialic acid inhibit the aggregation of CaOx crystals. The above findings show that sialic acid accounts for about 15-20% of the involvement of OPN in CaOx crystallization.

Analysis of osteopontin DNA in patients with urolithiasis.

We previously reported the importance of osteopontin (OPN) in the formation of urinary calculus. Since OPN protein is present in normal kidneys, we investigated the difference in OPN at the DNA level between normal subjects and urolithiasis patients. There has not been any genetic investigation of OPN in familial urolithiasis previously reported worldwide. To confirm hereditary predisposing factors for urolithiasis, changes in OPN DNA within a family were investigated in relation to the presence or absence of urinary calculus. Leukocyte OPN DNA from two normal subjects and five patients with urinary calculus was investigated by SSCP analysis: OPN DNA nucleotide sequence was determined, based on the result of SSCP analysis. As a result, a mutation of GCC to GCT, encoding amino acid position 250 (Ala-250) was found. To confirm the frequency of mutation at this site, OPN DNA was extracted from peripheral blood in 36 normal subjects (Con group), 25 patients with familial urolithiasis (FSF), and 40 patients with recurrent urinary calculus and who had had two or more previous episodes (RSF). The degree of mutation at Ala-250 was then examined by restriction fragment length polymorphism (RFLP) method. As described above, the nucleotide codon encoding the amino acid sequence position 250, Ala-250, was GCC in two normal subjects. This is the original codon. In five patients with urolithiasis it was GCT, showing a substitution of C with T. On examining the frequency of this mutation, the ratio of normal homozygous GCC was 11/36 in the Con group, 1/25 in FSF and 1/40 in RSF. The ratio of heterozygous GCC/GCT was 16/36 in the Con group, 15/25 in FSF and 26/40 in RSF, and the ratio of homozygous GCT was 9/36 in the Con group, 9/25 in FSF and 13/40 in RSF. Furthermore, the gene frequency of the normal codon GCC was 0.528 in the Con group, 0.3 in FSF and 0.35 in RSF, showing a significantly higher incidence in the Con group (P < 0.05). The gene frequency of mutated GCT was 0.472 in Con group, 0.7 in FSF and 0.65 in RSF, showing a significantly higher incidence in urolithiasis patients (P < 0.05). On investigating the inheritance of Ala-250 in five families in which both parent and offspring demonstrated urolithiasis, the nucleotide substitution in Ala-250 in parents with urolithiasis was inherited by their offspring. In all five families the offspring developed urinary calculus. This study showed that there is no difference in OPN structure between the Con group and urolithiasis patients. However, it was predicted that due to the frequency of normally coded GCC being high in the Con group a difference in the amount of OPN might be caused by a difference in transcription velocity between the two groups. Furthermore, it was suggested that examining the inheritance of Ala-250 within a family is a diagnostic method for identifying the predisposing hereditary factors for urolithiasis patients.

Localization and inhibitory activity of alpha(2)HS-glycoprotein in the kidney.

alpha(2)HS-Glycoprotein (HS), a crystal surface binding substance extracted from human urine, is considered to be one of the urinary macromolecular inhibitors in urolithiasis. In the present study, reverse transcription-polymerase chain reaction was used to examine HS mRNA expression, and immunohistochemical staining was used to reveal its localization in the human kidney. The inhibitory effects of recombinant human HS and native human HS on calcium oxalate crystal growth were examined in a seed crystal system. HS mRNA was found to be expressed in the human kidney, and it was located in the epithelial cells of distal and proximal renal tubular cells. However, neither recombinant HS nor native HS had an inhibitory effect on crystals in the protein concentration of urine of healthy humans. HS in the urine, therefore, does not seem to be a potent inhibitor in stone formation.

[Endopyelotomy with ureteral cutting balloon device: long-term follow up of 13 patients].

BACKGROUND: This study investigated the feasibility and long term results of retrograde endopyelotomy with the Acucise ureteral cutting balloon device in the management of ureteropelvic junction (UPJ) obstruction. METHODS: Thirteen patients (primary: 12, secondary: 1, male: 7, female: 6, mean age: 36) with UPJ obstruction were treated by the Acucise under fluoroscopic guidance. After cutting the stenotic area electrically using cutting wire and dilatation by the balloon, ureteral catheter (7-14 Fr) was inserted for 6-8 weeks. RESULTS: The mean operative time was 43 minutes, the median postoperative hospital stay was 4 days. The subjective success rate (disappearance of the abdominal pain) was 92% (11/12) and the objective success rate evaluated by radiographic studies was 62% (8/13). One patient needed a transfusion but no other major complication occurred in the treatment. The failure 5 patients were now under conservative follow up. CONCLUSION: Our limited data suggest that endopyelotomy with the Acucise device offer lower morbidity with slightly lower success rate compared other endopyelotomies. We believe that Acucise endopyelotomy can be an appropriate one of the first-line therapy for UPJO.

[Extracorporeal shock wave lithotripsy monotherapy for a renal stone in a 15-month-old child].

A 15-month old child visited our hospital with the chief complaint of macroscopic hematuria. Intravenous pyelography (i.v.p.) revealed a right renal stone (20 x 18 mm) with hydronephrosis and hydroureter. Extracorporeal shock wave lithotripsy (ESWL) was performed twice using a SEMENSE LITHOSTER for the stone. A cardboard and a towel were used to protect the lung and for focusing the shock waves. We achieved complete stone clearance with the ESWL monotherapy. I.v.p. and voiding cystography (VCG) after ESWL revealed disappearance of right hydronephrosis and hydroureter and no reflux. As of June 1995, his general condition is good and there are no recurrent stones.

[Long-term effect after total parathyroidectomy with autotransplantation for secondary hyperparathyroidism].

Although the short-term outcome of total parathyroidectomy combined with autotransplantation in cases of renal osteodystrophy has been reported by many investigators, few studies have been made on the long-term outcome of this surgical technique. We recently examined the long-term outcome of this surgery by following 19 cases for more than one year (range: 12-70 months, mean: 31.7 months). During the follow-up period, changes in subjective symptoms, biochemical parameters and bone mineral density (BMD) were monitored. At the end of the follow-up period, C-parathyroid hormone (C-PTH) and alkaliphosphatase (ALP) were significantly lower than their preoperative levels. Ca, P and %BMD showed no significant change from their preoperative levels, although %BMD tended to be higher than its preoperative level. Depending on the presence or absence of osteoarticular pain at the end of the follow-up period, the patients were divided into the improved group and the non-improved group. Of the 5 patients allocated to the non-improved group, 4 were female and only 1 was male. C-PTH and ALP were significantly higher in the non-improved group. %BMD was higher in the improved group than in the non-improved group, although this difference was not significant. In the non-improved group, 2 patients were suspected of having extra parathyroids, 1 was suspected of having recurrence, and 2 were suspected of having postoperative osteomalacia. Postoperative reduction in BMD was only seen in females, suggesting its relationship to postmenopausal osteoporosis.

[Indications of parathyroidectomy for bone disease associated with secondary hyperparathyroidism].

BACKGROUND: The indications and suitable operative time of parathyroidectomy for secondary hyperparathyroidism were discussed. METHODS: From October 1978 to September 1994 parathyroidectomy was performed for 71 patients who had bone and/or joint pain due to secondary hyperparathyroidism. There were 37 men and 34 women (mean age 48.4 years). The duration of dialysis treatment before parathyroidectomy was 0.8 to 19 years, with a mean of 10.9 years. RESULTS: Postoperative subjective improvement was noted in 69% of the patients. No significant difference was observed between the improved and non-improved groups regarding age and the duration of dialysis treatment. But the improvement rate in female patients was significantly lower than that in male patients. CONCLUSION: Patients with high carboxyl-terminal PTH level and generalized fibrous osteitis were good suitable objects for parathyroidectomy. But, those with high serum aluminum level were unsuitable objects for it. Furthermore, 99mTc-Pyrophosphate bone scintigraphy and bone mineral determination using dual photon absorptiometry (DPA) or dual energy X-ray absorptiometry (DEXA) were proved to be valuable for patient selection for parathyroidectomy.

The effect of osteopontin on the adhesion of calcium oxalate crystals to Madin-Darby canine kidney cells.

OBJECTIVE: We have recently reported that osteopontin protein (OPN) is present in calcium-containing urinary calculi and in rat distal tubular cells and that it is an important substance of the matrix in urinary stone formation. To investigate how OPN participates in urinary stone formation, we assessed the role of OPN in the adhesion of the surfaces of Madin-Darby canine kidney (MDCK) cells, which are distal tubular cells of the dog, to calcium oxalate crystals. METHODS: We cultured MDCK cells with OPN, thrombin, which is an OPN inhibitor, Arg-Gly-Asp peptide and Arg-Gly-Glu peptide as a control for Arg-Gly-Asp peptide, and examined changes in adhesion of calcium oxalate crystals to the cells by scanning electron microscopy and the calcium (45Ca) concentration around the cells. RESULTS: The 45Ca concentration in calcium oxalate crystals adhering to MDCK cells was about 1.4 times higher in MDCK cells incubated with OPN than in an MDCK-cell-negative group, and was about one half that in MDCK cells incubated with thrombin than in the group without MDCK cells. CONCLUSION: OPN is considered to be an accelerator of urinary stone formation because of the increase in adhesion of calcium oxalate crystals to the renal distal tubular epithelium in the presence of OPN. These findings suggest that OPN plays an important role in the formation of calcium-containing urinary stones.

Regulation of the expression of OPN mRNA in the rat as an experimental model of renal stone disease.

We have sequenced a cDNA of calcium oxalate urinary stone protein extracted with EDTA. cDNA sequences showed complete homology between urinary stone protein and human osteopotine (OPN, bone sialoprotein 1). In this study, we investigated the expression of OPN mRNA in rat kidney serving as experimental models for several conditions that are considered to be risk factors in human renal stone formation. In the renal stone formation model, the expression of OPN mRNA in the distal convoluted tubule of the kidney was enhanced compared with the control which was found sporadically positive by in situ hybridization. By Northern blot analysis, the expression of OPN mRNA was increased in pyelonephritis and hydronephrosis models compared with the control, but no changes were observed in dietary-acid or base-loading models. The expression of OPN mRNA was markedly inhibited in the renal stone formation model by concomitant administration of estradiol and/or progesterone.

[Influence of genetic factors on family history of upper urinary stones].

The family history between patients with upper urinary tract stones and healthy subjects was compared to evaluate the possible involvement of genetic factors in obtaining information through a questionnaire. The patients showed a significantly more marked history than the healthy subjects (p < 0.001). In particular, recurrent stone formers showed a significantly more marked history than single stone formers (p < 0.05). Compared with the healthy subjects, a more marked family history was observed in the parents, brothers and sisters, and children, but not in the spouse (p < 0.05-0.005). However, the family history was not affected by consanguineous marriage. A more marked family history was observed in patients with upper urinary tract stones, suggesting the involvement of genetic factors in the development of upper urinary tract stones. In particular, genetic factors seem to be more closely involved in recurrent stone formers.

Clinical efficiency of type-IV collagen in extracorporeal shock wave lithotripsy.

We previously reported a patient who developed anti-glomerular basement membrane antibody-induced glomerulonephritis (GBM-GN) after extracorporeal shock wave lithotripsy (ESWL). To determine whether ESWL causes anti-GBM antibody production thereby inducing GBM-GN, we measured serum levels of type-IV collagen (the most major component of GBM) before and after ESWL. Serum samples were obtained from 13 patients with renal stones and 15 with ureteral stones. The serum type-IV collagen level was determined by a radioimmunoassay method. No significant changes were observed in the type-IV collagen level after ESWL in each patient group. Type-IV collagen was abundant in the GBM but was not released into the blood after ESWL. Therefore, in patients with urinary tract stones, it is not likely that type-IV collagen, a hidden antigen in the renal glomeruli, is exposed or released into the blood after ESWL, resulting in autoantibody production and GBM-GN.

Osteopontin mRNA in the kidney on an experimental rat model of renal stone formation without renal failure.

We had sequenced a cDNA of calcium oxalate urinary stone protein extracted with 0.1 M EDTA. cDNA sequences showed complete homology between urinary stone protein and human osteopontin (OPN, bone sialoprotein I). In the present study, we investigated the expression of OPN mRNA in the rat kidney in an experimental model of renal stone formation using glyoxylic acid and 1,25-dihydroxyvitamin D3 (D3). In the renal stone formation model with and without renal failure, OPN mRNA was shown to be localized by in situ hybridization using an OPN cRNA probe mainly in the distal convoluted tubule of the kidney, and was enhanced compared with the normal control which was sporadically positive. By Northern blot analysis, the expression of OPN mRNA was shown to be increased by about 5.2-fold in the renal stone formation model and 2.3-fold in D3-administered rats compared with controls. However, no change in the expression of OPN mRNA was observed in an acute renal failure model induced by gentamicin or in rats administered glycoxylic acid alone. Therefore, the promotion of OPN mRNA expression was intrinsic to this stone formation model, and not secondary to acute renal failure because of obstruction by microcrystals in the renal tubules or gentamicin.

Sequencing of a urinary stone protein, identical to alpha-one antitrypsin, which lacks 22 amino acids.

We have extracted and purified proteins from calcium containing urinary stones with 4 M guanidine chloride and sequenced the amino acids of the proteins. The protein of approximately 49kDa was defined as human alpha-one antitrypsin (AT, from 23rd to 42nd amino acids of NH2-terminal) by amino acid sequence analysis. The ratio of the amount of AT to total proteins was 34.9% analyzed by densitometer. AT is presumably involved in stone formation as a coprecipitating substance because equilibrium dialysis revealed that AT has no affinity for calcium.

[Evaluation of preoperative diagnosis of primary hyperparathyroidism--special reference to normocalcemic cases].

Since the opening of our clinic 117 years before, we have treated 62 cases of primary hyperparathyroidism (PHPT), among which there were 6 cases (1 male, 5 females) whose calcium levels fell within the normal range. However, in all these cases the serum ionized calcium (Ca++) levels and the serum ionized calcium/calcium ratio (Ca++/Ca ratio) were high. Moreover, in comparing them with hypercalcemic patients (56 cases), the serum Ca++ levels were significantly lower, but the (Ca++/Ca ratio) was significantly higher. Also, the excised weight of 606.1 +/- 520.3 mg was significantly smaller than that of hypercalcemic patients, which was 1,967.9 +/- 2,086.3 mg. Preoperative locations showed significantly lower levels in comparison with hypercalcemic patients by all methods including computed tomography (CT), ultrasonography, scintigraphy, and magnetic resonance imaging (MRI). In normocalcemic patients following parathyroidectomy, although the decrease in serum calcium levels was not significant, the serum Ca++ levels and the Ca++/Ca ratio decreased significantly, so that not only are they useful parameters for preoperative diagnosis of PHPT, but they are also considered necessary and indispensable for observation of the post-operative course and judging therapeutic effects including the operation. Based on our study we concluded that in multiple and recurrent stone formers with normal range of serum Ca levels, regardless of the presence or absence of local diagnosis, if the serum Ca++ level and Ca++/Ca ratio are high, existence of primary hyperparathyroidism must be suspected, and adequate treatments should be instituted promptly.

Studies on changes in parameters of the coagulation and fibrinolysis in association with extracorporeal shock wave lithotripsy.

Tissue damage by extracorporeal shock wave lithotripsy (ESWL) is assumed to be attributable to ischemic changes in the treated region surrounding the particular vessel which is first ruptured by shock waves. Such changes cannot take place without being accompanied by acceleration of coagulation and fibrinolysis. In the literature on renal damage by ESWL, no parameters of the coagulation and fibrinolysis of blood were used. The present study was designed to investigate renal damage by shock waves through the quantification of sequential changes in the following parameters between before and after ESWL: thrombin antithrombin III complex (TAT), alpha 2-plasmin inhibitor-plasmin complex (PIC), fibrin and fibrinogen degradation products (FDP) and D-dimer (D-D). In ESWL for renal stones, a significant acceleration of TAT occurred on the 1st postoperative day, followed by acceleration of PIC on the 3rd postoperative day. A transient acceleration was observed for FDP and D-D after operation. The levels of these parameters, however, returned to normal by the 1st postoperative week. In ESWL for ureteral stones, unlike for renal stones, none of the parameters showed statistically significant acceleration. In the construction of percutaneous nephrostomy (PNS) cases for ureteral stones before ESWL, none of the parameters showed significant acceleration either. Changes in these parameters of coagulation and fibrinolysis due to ESWL for renal stones were greater than those of construction of PNS or ESWL for ureteral stones. The reason for the difference of the alteration in these parameters between renal stones and ureteral stones were more abundant vessels in the kidney than the ureter. All these changes in the parameters, however, disappeared within almost 1 week.

Continuous evaluation for retroperitoneal hematoma following extracorporeal shock wave lithotripsy.

In this paper we report on a patient with extensive retroperitoneal hematoma due to extracorporeal shock wave lithotripsy (ESWL) for a renal stone. The patient had a negative history of previous primary renal disease or risk factors for retroperitoneal hemorrhage after ESWL. The hematoma was treated conservatively and it was completely absorbed 9 months after ESWL as evaluated by computed tomography. Gd-DTPA-enhanced dynamic magnetic resonance imaging (dynamic MRI) was performed immediately after formation of the hematoma. The decrease in renal blood flow in the affected kidney could be observed in this patient by dynamic MRI and its time intensity curve.

Molecular cloning and sequencing of cDNA encoding urinary stone protein, which is identical to osteopontin.

We have sequenced a cDNA of urinary stone protein. cDNA sequences show complete homology between urinary stone protein and human osteopontin (bone sialoprotein) (nucleotides 265-886 and 1183-1424). Osteopontin is a recently discovered bone matrix protein which has been implicated in mediating mineral formation within bone extracellular matrix. This result shows that osteopontin is presumably involved in stone formation as stone matrix.

Renal damages after extracorporeal shock wave lithotripsy evaluated by Gd-DTPA-enhanced dynamic magnetic resonance imaging.

Renal damages after extracorporeal shock wave lithotripsy (ESWL) were evaluated by magnetic resonance imaging (MRI) including Gd-DTPA-enhanced dynamic MRI in 37 patients with renal stone by spin echo methods (T1 and T2-weighted scan) and small tip angle gradient echo method (T2-weighted scan). Sixty-eight percent of the patients had changes in the MRI findings after ESWL. The frequently observed findings were perirenal fluid collection (38%), loss of corticomedullary junction (35%), and increased signal intensity of muscle and other adjacent tissue (34%). Preoperative Gd-DTPA-enhanced dynamic MRI showed low intensity band which suggests Gd-DTPA secretion from the glomerulus into the renal tubulus. In all cases the low intensity band became unclear after ESWL because of renal contusion due to ESWL. MRI, including Gd-DTPA-enhanced dynamic MRI, is considered to be a good procedure for evaluation of renal damages due to ESWL.

Characteristics and usage of different ureteral stent catheters.

Presuming that complications associated with ureteral stenting vary in type and occurrence depending on the material and cross-section of the stent, six types of stents immersed in 48 different preparations of artificial urine for 1 month to observe surface changes with a scanning electron microscope. As a result, there was less encrustation on the silicone material compared with other material types, probably due to the smoothness of the surface. This may be related with higher frequency of spontaneous removal or migration to the bladder of this catheter type. Because silicone catheters have softer and thicker walls with a narrow lumen, they may be appropriate for long-term stenting, but not for urinary drainage. In alkaline bacteriuria, struvite encrustation was observed on all stents. This reaction was especially intense with Towers peripheral stents, which had most irregular and uneven surfaces. In aseptic alkaline urine, calcium phosphate crystals partly covered with proteinaceous debris were noted on catheter surfaces. Although in some patients encrustation of uric acid occurred in the bladder portion of the stents, there was no uric acid encrustation in this experimental study.