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At least 91 records · Page 5Linked to original sources

PubMed2002

Extracorporeal shock wave lithotripsy of pancreatic duct stones and patient factors related to stone disintegration.

BACKGROUND: Stones in the main pancreatic duct (MPD) are difficult to remove by endoscopic devices alone in some patients who have chronic pancreatitis. We treated these patients with extracorporeal shock wave lithotripsy (ESWL) and analyzed the patient factors related to disintegration. METHODS: Twenty-four patients were treated with ESWL alone or with combined endoscopic-ESWL to disintegrate or remove MPD stones. RESULTS: Ten patients were treated by ESWL alone and 14 by combined endoscopic-ESWL. A total of 19 patients (79%) were effectively treated by either method. The mean MPD diameter decreased significantly after ESWL. In most of the patients who had chronic abdominal symptoms, these symptoms were relieved at discharge. Severe side effects of complications did not occur during ESWL therapy. Acute abdominal symptoms and a significant increase in the white blood cell count, total bilirubin, and aspartate aminotransferase were observed only immediately after ESWL. Although there were no significant differences, we observed that the patients with a higher stone disintegration success rate showed the following factors: (1) female, (2) non-alcoholic pancreatitis, (3) younger age, (4) shorter duration of symptoms, (5) smaller stones, and (6) a lower Hounsfield unit value of stones. Although about half of the patients had recurring abdominal symptoms and stones during a follow-up period of 12 months, the stones which caused relapse in short-term intervals were disintegrated easily by ESWL. CONCLUSIONS: We may consider the application of ESWL therapies for patients who show the factors associated with easily disintegratable stone conditions. These therapies are highly effective and relatively safe procedures for pancreatic duct stones in such patients.

Adult↗

PubMed1998

Agglomeration inhibition reflected stone-forming activity during long-term potassium citrate therapy in calcium stone formers.

OBJECTIVES: The agglomeration of preformed crystals of calcium oxalate has been hypothesized to be the rate-limiting step in renal stone-forming activity (SFA). The effect of urine on the in vitro inhibition of agglomeration of seed crystals of calcium oxalate monohydrate, designated [tm], has been used to monitor SFA in calcium oxalate stone formers (CaOxSF). The objective of the present study was to determine whether [tm] could be used to help monitor the long-term effectiveness of oral potassium citrate therapy (K-Cit-Rx) in CaOxSF. METHODS: Clinic and radiographic (or ultrasound) reports were evaluated for 80 patients, aged 20 to 72 years, 55 men and 25 women, who were treated with oral K-Cit for recurrent calcium oxalate urolithiasis at the Ochsner Stone Clinic between January 1992 and July 1996. Seventy-five of these patients had at least one 24-hour citrate excretion rate of less than 3.0 mm/day before or after K-Cit-Rx. SFA graded on a scale of -2 to +2 by radiographic criteria was combined with information on stone passage to evaluate clinical stone status, and 24-hour urine collections were evaluated for volume, pH, calcium, citrate, uric acid, oxalate, creatinine, and [tm] on free diet before and after 6 to 53 months of K-Cit-Rx. Historical information on procedures performed for urolithiasis before and on K-Cit-Rx was also reviewed. RESULTS: K-Cit-Rx resulted in increased urine pH (P <0.0001) and decreased calcium (P=0.0475), [tm] (P=0.0045), number of stones passed per year (P=0.0016), and remedial procedures per year (P <0.0001). Patients taking allopurinol in addition to K-Cit required higher doses (P <0.0001) of K-Cit to control their disease, had lower pretreatment urine pH (P=0.0493), and showed greater increase in urine citrate (P=0.0092) than those on K-Cit alone. Those taking high-dose K-Cit were younger (P=0.0363) and showed greater decrease in SFA (P=0.0005) than those taking lower doses. A small group of 10 medication refractory patients, who retained (n=9) or increased (n=1) their stone burden during K-Cit-Rx, was identified. Compared with the medication-responsive group, the refractory patients were older (P=0.0124), and had greatly increased SFA (P <0.0001) and higher (P=0.0347) urine pH before and during (P=0.0173) treatment (data not shown). CONCLUSIONS: The data confirm that [tm] can be used not only to verify previously documented stone formation rate but also to help evaluate the long-term effectiveness of therapy. In this report, changes in [tm] after K-Cit-Rx reflected decreased stone formation rate and decreased remedial procedures.

Adult↗

PubMed2002

Calcium oxalate stone formation in genetic hypercalciuric stone-forming rats.

BACKGROUND: Over 54 generations, we have successfully bred a strain of rats that maximizes urinary calcium excretion. The rats now consistently excrete 8 to 10 times as much calcium as controls, uniformly form poorly crystalline calcium phosphate kidney stones, and are termed genetic hypercalciuric stone-forming (GHS) rats. These rats were used to test the hypothesis that increasing urinary oxalate excretion would not only increase the supersaturation with respect to the calcium oxalate solid phase, but also would increase the ratio of calcium oxalate-to-calcium phosphate supersaturation and result in calcium oxalate stone formation. METHODS: To increase urine oxalate excretion an oxalate precursor, hydroxyproline, was added to the diet of male GHS rats. The GHS rats were fed a standard 1.2% calcium diet alone or with 1%, 3% or 5% trans-4-hydroxy-l-proline (hydroxyproline). RESULTS: The addition of 1% hydroxyproline to the diet of GHS rats led to an increase in urinary oxalate excretion, which did not increase further with the provision of additional hydroxyproline. The addition of 1% and 3% hydroxyproline did not alter calcium excretion while the provision of 5% hydroxyproline led to a decrease in urine calcium excretion. The addition of 1% hydroxyproline led to an increase in urinary calcium oxalate supersaturation, which did not further increase with additional hydroxyproline. The addition of 1% and 3% hydroxyproline did not alter urinary supersaturation with respect to calcium hydrogen phosphate while the addition of 5% hydroxyproline tended to lower this supersaturation. Compared to rats fed the control and the 3% hydroxyproline diet the addition of 5% hydroxyproline increased the ratio of calcium oxalate supersaturation to calcium phosphate supersaturation. Virtually all rats formed stones. In the control and 1% hydroxyproline group, all of the stones were composed of calcium and phosphate (apatite), in the 3% hydroxyproline group the stones were a mixture of apatite and calcium oxalate, while in the 5% hydroxyproline group all of the stones were calcium oxalate. CONCLUSIONS: The provision of additional dietary hydroxyproline to GHS rats increases urinary oxalate excretion, calcium oxalate supersaturation and the ratio of calcium oxalate-to-calcium phosphate supersaturation, resulting in the formation of calcium oxalate kidney stones. Thus, with the addition of a common amino acid, the GHS rats now not only model the most common metabolic abnormality found in patients with nephrolithiasis, hypercalciuria, but form the most common type of kidney stone, calcium oxalate.

Animals↗

PubMed1995

Cholesterol bile duct stones with no stones in the gallbladder.

Common bile duct stones are usually associated with stones in the gallbladder. During the period 1989-1991, however, we encountered 17 patients with common bile duct (CBD) stones without gallbladder stones who had presented with obstructive jaundice and cholangitis. Their ages ranged between 30 and 72 years; 10 were female and seven male. Five of them had a deceptive presentation and were initially misdiagnosed as having a malignant lesion. It was endoscopic retrograde cholangiopancreatography that correctly diagnosed the presence of CBD stones in all 17 patients. Therapeutic sphincterotomy led to subsidence of cholangitis in 16 patients and retrieval of stones in 13 of them. Three patients required nasobiliary decompression because stones could not be retrieved. One patient required emergency surgery due to flare-up of cholangitis. Cholesterol concentration of the retrieved stones was 70-92% of the dry weight. Thus, these 17 patients formed a distinct subgroup who had cholesterol CBD stones with stoneless gallbladder, and five of these 17 patients had presentations mimicking malignant lesions.

Adult↗

PubMed2006

Identification of risk factors for stone recurrence after endoscopic treatment of bile duct stones.

Recurrence of bile duct stones after endoscopic stone removal has been reported ranging from 4 to 24%. The risk of late complications such as stone recurrence is an important issue, especially for relatively young, otherwise healthy, patients with many years of future exposure time. The risk factors true recurrence of bile duct stones after endoscopic sphincterotomy (EST) and stone clearance are suboptimally defined. If patients at significant risk for stone recurrence could be identified, closer follow-up, earlier intervention, and possible preventive measures could theoretically decrease stone recurrence and late complications. The majority of patients with common bile duct stone who have EST and stone clearance will have no further biliary events during the remainder of their life. Whether identifying risk factors for recurrence can improve outcomes by prophylactic treatments or earlier interventions needs further prospective study.

Cholangiopancreatography, Endoscopic Retrograde↗

PubMed1998

A review of preweighed, packaged die stone versus bulk die stone use in a dental school.

PURPOSE: This study compared the quantity of preweighed, packaged die stone use to bulk die stone use by dental students. MATERIALS AND METHODS: Starting in September 1994, all the bulk die stone was removed from the dental clinic, and only preweighed packages of die stone (Silky-Rock, Whip Mix) were available to students. At the end of August 1995 and August 1997, the amount of preweighed die stone used by the students was determined and compared with the amount of bulk die stone (DieKeen, Modern Materials) used during the period of September 1993 to August 1994. RESULTS: Between September 1994 and August 1997, the students used 42% less per annum of the preweighed, packaged die stone than the previous annual use of bulk die stone. The laboratories were much cleaner when the preweighed packages were used, and fewer cleaning staff were required. The environment was also cleaner for the laboratory staff, who used to fill the bulk containers with gypsum products. CONCLUSIONS: Students used 42% less die stone per annum when using the preweighed packages.

Calcium Sulfate↗

PubMed2005

Thiazides reduce brushite, but not calcium oxalate, supersaturation, and stone formation in genetic hypercalciuric stone-forming rats.

Over 59 generations, a strain of rats has been inbred to maximize urine calcium excretion. The rats now excrete eight to 10 times as much calcium as controls. These rats uniformly form calcium phosphate (apatite) kidney stones and have been termed genetic hypercalciuric stone-forming (GHS) rats. The addition of a common amino acid and oxalate precursor, hydroxyproline, to the diet of the GHS rats leads to formation of calcium oxalate (CaOx) kidney stones. Hydroxyproline-supplemented GHS rats were used to test the hypothesis that the thiazide diuretic chlorthalidone would decrease urine calcium excretion, supersaturation, and perhaps stone formation. All GHS rats received a fixed amount of a standard 1.2% calcium diet with 5% trans-4-hydroxy-l-proline (hydroxyproline) so that the rats would exclusively form CaOx stones. Half of the rats had chlorthalidone (Thz; 4 to 5 mg/kg per d) added to their diets. Urine was collected weekly, and at the conclusion of the study, the kidneys, ureters, and bladders were radiographed for the presence of stones. Compared with control, the addition of Thz led to a significant reduction of urine calcium and phosphorus excretion, whereas urine oxalate excretion increased. Supersaturation with respect to the calcium hydrogen phosphate fell, whereas supersaturation with respect to CaOx was unchanged. Rats that were fed Thz had fewer stones. As calcium phosphate seems to be the preferred initial solid phase in patients with CaOx kidney stones, the reduction in supersaturation with respect to the calcium phosphate solid phase may be the mechanism by which thiazides reduce CaOx stone formation.

Animals↗

PubMed1975

Influence of stone mixing agents, impression materials and lubricants on surface hardness and dimension of a dental stone die material.

The influence of different stone mixing agents, impression materials and lubrication methods on the surface hardness of a stone die material has been evaluated. For one impression material the dimensional effect of the mixing agents and lubrication on the dies was also studied. The stone die material was mixed with water or a gypsum hardener and allowed to set on surfaces of glass, agar-agar, polyether, polysulfide and silicone impression materials. The lubrication methods for the stone were mineral oil, water soluble lubricant and mineral oil followed by water soluble lubricant. The surface hardness was measured according to the Brinell test. The Brinell test was chosen after a comparative study of the Brinell, Vickers and Knoop hardness test methods. The results showed that gypsum hardener was preferable to distilled water. The impression materials appear to have influence on the surface hardness of stone. The effect differed on water mixed and hardener mixed stone which emphasizes the importance of the mixing agent. All lubrication decreased the surface hardness of stone. With hardener mixed stone the combination of mineral oil followed by water soluble lubricant seemed preferable. Neither the gypsum hardener nor the lubrication influenced the dimension of the stone die material.

Dental Impression Materials↗

PubMed2001

[Clinical experience of in situ extracorporeal shock wave lithotripsy using ESL-500A for bilateral ureteral stones and ureteral stones in a solitary, or a functionally solitary kidney].

Extracorporeal shock wave lithotripsy (ESWL) using ESL-500A was performed for the treatment of 18 cases of bilateral ureteral stones and 3 cases of a solitary or a functionally solitary kidney with ureteral stones from September 1991 to February 2000. Sixteen cases of the former and all 3 cases of the latter were treated by in situ ESWL, and the other 2 cases of bilateral ureteral stones were treated with auxiliary procedures. No residual stones were observed in any cases except for one of bilateral ureteral stones treated by in situ ESWL. The results show that in situ ESWL using ESL-500A seems to be useful for the treatment of bilateral ureteral stones and ureteral stones in a solitary kidney, including a functionally solitary kidney. However, auxiliary treatment will be needed in cases of urinary tract infection, undetectable stones by ultrasonography, or bilateral large stones.

Adolescent↗

PubMed2006

The effect of adding a stone base on the accuracy of working casts using different types of dental stone.

AIM: Gypsum products are used for the preparation of stone casts of oral and maxillofacial structures and as important adjuncts to dental laboratory operations involved in the production of dental prostheses. The aim of this study was to determine the effect on the dimensional accuracy of a working cast of adding a stone base using different stone products. METHODS AND MATERIALS: A total of forty impressions of a mandibular dentoform were made. The impressions were dried with compressed air and stored at room temperature for 24 hours before pouring stone casts. The forty impressions were randomly divided into four groups of ten each. All forty impressions were poured once using one pre-weighed 140 Gm package of Silky Rock (SR) Type IV improved stone (Whip Mix Corporation, Louisville, KY, USA ) per impression. All working casts and the die setups were prepared according to the manufacturer's recommendations for pin placement (M.R. Dual pin and sleeve). Four different types of dental stone (II, III, and IV) and Flow Stone (FS) were used as bases for the working models. They were mixed according to the manufacturer's recommendations. The lower posterior teeth were flattened on the dentoform prior to taking the impressions. All were indexed using a mounted abrasive disc. Four teeth were selected as follows: 21, 28, 30, and 18. These represented A, B, C, and D landmarks, respectively. All measurements (five times for each specimen) were made with a Universal measuring microscope (Unitron Instruments, Inc., Bohemia, NY, USA). After the pre-sectioned measurements were recorded, the stone base was poured. A manual hand saw was used to section and fabricate removable dies for the mandibular landmarks A, B, C, and D. The dies were later seated and removed ten times to simulate the average amount of handling during laboratory procedures. Each die was carefully seated and measurements were made using the same technique as for the master model and unsectioned casts. Multivariate repeated measures analysis of variance (MANOVA) was used to test the difference in three different landmark distances (AB, AC, and AD) among the master model before and after sectioning of the working dies and among the four different base materials. Univariate analysis of variance (ANOVA) was conducted for each measurement, AB, AC, and AD to test the difference in landmark distances on the master model at pre sectioning and then at post sectioning using four different base materials. When there was a significant main effect (p < .05), the Student-Newman-Keul's (SNK) were used to test for pair wise comparison of means (P<0.05). RESULTS: The results of the MANOVA indicated there was a significant difference in three landmark measurements on the master model before and after sectioning of the working dies for the four different base materials (F = 6.60, p = 0.0001). In addition there was a significant difference in three landmark measurements on the master model at: (1) pre sectioning (p = 0.0001), (2) between the master model and SR material (p = 0.0002), (3) between the master model and Laboratory Plaster (LP) material (p = 0.0001), (4) between the master model and Quick Stone (QS) material (p = 0.0001), and (5) between the master model and FS material (p = 0.0001).

Calcium Sulfate↗

PubMedDate not supplied

Computed tomography density of gallbladder stones may aid in predicting the rate of stone fragmentation with extracorporeal lithotripsy.

Thirty-six patients with gallbladder stone(s), 21 with solitary stone and 15 with multiple stones up to five in number, were treated by a single session of extracorporeal shock wave lithotripsy. In eight patients (group A), stones were gradually fragmented from the surface, producing fine powderlike fragments which made residual stones invisible, leading to reduced therapeutic efficacy. In 13 patients (group B), residual stones remained visible up to 2,400 shocks, though they showed similar fragments. Such fragments did not appear throughout treatment in 14 patients (group C). Computed tomography (CT) attenuation number, when the region of interest was settled on the whole stone, increased in the order of group A, B, and C. When the distribution of CT density on stones was analyzed, the density was diffusely lower than 50 HU in all patients in group A, higher than 50 HU only on the surface in all patients except for two in group B, and diffusely higher than 50 HU in all patients except for one in group C. CT findings may be useful for predicting the fragmentation mode of gallbladder stones by extracorporeal shock wave lithotripsy.

Adult↗

PubMed1995

Residual stones after percutaneous nephrolithotomy; sensitivities of different imaging methods in renal stone detection.

Kidneys of 35 renal stone patients treated with percutaneous nephrolithotomy (PNL) were examined at 12-36 months (mean 23 months) after the procedure by plain radiography (PR), conventional linear tomography (LT), computed tomography (CT), and ultrasonography (US) to find out the long-term stone-free rate as well as the accuracy of these imaging methods to detect residual or recurrent renal stones. The present series included 36 kidneys with a 56% postoperative stone-free status examined by plain radiography and a 58% one examined by linear tomography at 12-36 months. CT showed 47% and US 72% of the kidneys to be stone-free, respectively. The sensitivity of CT was superior to plain radiography (P < 0.05), linear tomography (P < 0.05) or US (P < 0.001) in the detection of residual or recurrent stones after percutaneous nephrolithotomy analyzed statistically by McNemar's test. In the same group of 35 patients, which consisted of the above 36 postoperative kidneys together with 19 contralateral kidneys, a total of 55 kidneys were evaluated by the above methods, revealing 56 stones in 31 kidneys. Of these stones 95% were detected by CT, 70% by plain radiography, 68% by linear tomography, and 32% by renal US. Of the 55 kidneys, 14 contained 20 stone fragments smaller than 3 mm, and 26 kidneys carried 43 concrements smaller than 6 mm. The sensitivities of the four imaging methods in the detection of these small fragments were as follows: plain radiography 60% and 60%, linear tomography 55% and 58%, CT 95% and 93%, and US 15% and 26%.(ABSTRACT TRUNCATED AT 250 WORDS)

Follow-Up Studies↗

PubMed1993

Variability of the calcium ion activity with pH in stone-forming and non-stone-forming urine.

In recurrent renal stone-formers (N = 20) and matched healthy adults (N = 20), the actual activity of ionized calcium (alpha Ca2+) and pH were determined in whole urine with an ion-selective electrode. No significant difference was found for the actual median activity of ionized calcium, however the actual median pH was significantly higher in stone-formers compared to healthy adults (pH = 5.57 vs. pH = 5.24; p < 0.005). The relationship between Ca2+ activity and pH was studied in each collected urine by titration with HCl/NaOH. In all urines the Ca2+ activity decreased with increasing pH in a typical bifasic manner. All curves showed a characteristic "breaking point" at a similar median pH in the stone-formers and in the healthy adults (pH = 6.81 vs. pH = 6.77) (NS). However the slope of the curves in the stone-formers and healthy adults changed from a median value of delta lg alpha Ca2+/delta pH of -0.139 and -0.173 (NS) respectively, to a highly significant difference of -1.326 and -1.053 (p < 0.0001) between the groups, indicating increased binding/precipitation of Ca2+ in stone-formers than in healthy adults supporting the theory of the lack of inhibitors in stone-formers. The strong relationship between the activity of ionized calcium and pH, combined with a higher actual pH and a higher decrease of ionized calcium with pH in stone-formers than in healthy adults, indicates hydrogen ion as a major factor in stone-formation. The close relationship between Ca2+ activity and pH indicates the need for simultaneous measurements of the pH in order to interpret data for the Ca2+ activity. In order to preserve a low urinary pH, where Ca2+ is predominantly in a free ionic state, our results suggest that treatment with acidifying salts could be a logical choice in order to prevent stone-formation.

Adult↗

PubMed1995

Low pretreatment gallbladder stone densities at computed tomography predict rapid stone clearance following extracorporeal shock wave lithotripsy.

The importance of routine computer tomographic (CT) stone analysis in optimizing the therapeutic outcome after extracorporeal shock wave lithotripsy (ESWL) remains controversial. The aim of the present prospective study was to seek a correlation between CT findings and stone clearance rates after ESWL in 159 patients. One hundred fifty-nine symptomatic patients (116 females, 43 males) with solitary radiolucent gallbladder stones underwent CT for stone analysis before lithotripsy. In Group I (<50 HU, n=104), stone clearance was achieved in 55.8% of patients within 6.11+/- 6.95 months; in Group II (51-100 HU, n = 28), in 50.0% of patients within 11.2 +/- 10.3 months; in Group III (>100 HU, n = 27) in 29.7% of patients within 9.60 +/- 6.96 months. The mean follow-up period was 17.9 +/- 10.0 months. Patients in Group I showed a significantly higher rate of stone clearance than those in Groups II and III (p < 0.001) as well as a significantly shorter time for the achievement of total stone clearance than either of the other groups (p < 0.001). The authors conclude that CT stone analysis provides a more accurate method of selecting patients suitable for ESWL and may be of importance in predicting the expected length of time for achieving complete stone clearance.

Absorptiometry, Photon↗

PubMed2026

Novel non-contrast computed tomography parameters for predicting spontaneous stone passage and surgical requirement in ureteral stones: The role of ureteral wall thickness and dilatation ratio.

We investigated the predictive value of standard non-contrast computed tomography (NCCT) measurements, the ureteral dilatation ratio (DDR) and intraluminal urine stasis markers, for spontaneous stone passage (SSP) versus surgical intervention in patients with ureteral stones. We also evaluated ureteral wall thickness (UWT) as a practical clinical marker. This retrospective study included 461 patients diagnosed with ureteral stones via NCCT. Patients were categorised into two groups based on clinical outcomes: the spontaneous passage group (MET; n = 229) and the endoscopic surgery group (URS; n = 232). Stone volume, stone density (HU), UWT, DDR and intraluminal urine attenuation values were measured for all patients. Independent risk factors were identified using a multivariate logistic regression model and clinical cut-off values were determined via ROC curve analysis. Stone volume, density, UWT and hydronephrosis grade were all significantly higher in the URS group. Multivariate regression analysis revealed that increased UWT (OR: 5.03, 95% CI: 3.66-6.90; p < 0.001) was the strongest independent predictor of surgery. Higher DDR (OR: 1.88; p = 0.003), advanced hydronephrosis, stone volume, and density also increased surgical risk. A UWT cut-off ≥ 2.97 mm predicted surgery with 84.8% sensitivity and 84.3% specificity (AUC: 0.872). A DDR cut-off > 1.79 yielded 81.7% specificity and 40.4% sensitivity. UWT weakly correlated with stone volume (r = 0.145), indicating wall thickening reflects an inflammatory response rather than a mere mechanical consequence. UWT is a superior predictor of SSP failure, supported by increased DDR as a highly specific complementary risk factor. These parameters could help clinicians to identify patients who would benefit from early surgical counselling and intervention rather than prolonged conservative management.

Humans↗

PubMed1996

Noncholesterol sterols in bile and stones of patients with cholesterol and pigment stones.

Human bile and cholesterol gallstones contain sterols including methylated (lanosterol and other dimethyl and monomethyl sterols), and demethylated cholesterol precursor sterols (delta 8-lathosterol, lathosterol, and desmosterol), plant sterols (campesterol and sitosterol), and cholestanol. The aim of the study was to analyze the noncholesterol sterols in gallbladder bile and stones from female and male patients with cholesterol stones (CS) and pigment stones (PS) to ascertain whether any sterol fraction contributes to the gallstone formation. Classification of gallstones to CS and PS was performed on the basis of the stone cholesterol content. The study group consisted of 165 consecutive cholecystectomized patients, 150 with CS and 15 with PS. Bile acids and sterols were quantitated using gas-liquid chromatography (GLC). The biliary lipid and noncholesterol sterol/cholesterol proportions were similar in the CS and PS patients. The proportions of methylated and plant sterols were significantly lower in the CS than in bile, whereas those of delta 8-lathosterol, lathosterol, and cholestanol were significantly higher. The PS, in contrast to the CS, were neither sex nor weight related. The bile acid and phospholipid concentrations and the proportions of lanosterol, delta 8,24-dimethylsterol, and sitosterol were up to 50 times higher and those of delta 8-lathosterol and lathosterol twice lower in the PS than in the CS. The results suggest that, in general, the stones with low cholesterol content are proportionately richer in nonpolar precursor and plant sterols and lower in demethylated precursors, the situation being opposite for the CS. The stone/bile ratios suggest that in both stone groups, but especially in the CS, levels of the polar precursor sterols and cholestanol were enriched in the stone, whereas levels of the nonpolar precursor sterols, and to a lesser extent plant sterols, were not enriched in the stone despite their high biliary proportions.

Bile↗

PubMedDate not supplied

Laser lithotripsy of difficult bile duct stones by means of a rhodamine-6G laser and an integrated automatic stone-tissue detection system.

This report describes the initial clinical implementation of a new laser lithotripter system capable of effective fragmentation of common bile duct stones with a high degree of safety provided by an integrated stone-tissue detection system. This system automatically terminates laser pulse transmission if tissue contact is sensed. Eighteen patients with giant or impacted common bile duct stones refractory to standard treatment techniques were treated via the endoscopic retrograde route using a rhodamine-6G dye laser with an integrated stone-tissue detection system. In the event of tissue contact, the stone-tissue detection system cuts off the laser pulse after 190 ns (after transmission of 5% to 8% of the total pulse energy). Nine patients were treated under cholangioscopic control, and nine patients were treated blindly under fluoroscopic control using only standard duodenoscopes with either a 6F standard endoscopic retrograde cholangiopancreatography catheter (4 patients), a 6.8F balloon catheter (3 patients), or a laser lithotriptor basket (2 patients). Laser-induced fragmentation was achieved in all 18 patients (100%). Sixteen of 18 patients (89%) became completely stone-free after completion of the treatment, including additional intracorporeal shock wave lithotripsy in five patients. The only major complications occurred in one fully anticoagulated patient with a prosthetic heart valve who developed significant hemobilia and transient cholangitis but recovered after conservative treatment. Laser lithotripsy using the rhodamine-6G dye laser plus stone-tissue detection system appears safe and effective and allows "blind" fragmentation of difficult common bile duct stones to be performed under radiologic control.

Adult↗

PubMed1991

Trace elements and urinary stone formation: new aspects of the pathological mechanism of urinary stone formation.

The urinary stone, serum and 24-hour urine concentrations of 14 trace elements were determined in urinary stone patients by inductively coupled plasma atomic-emission spectroscopy. The data obtained for 25 active stone patients and 32 whose last stone episode had occurred at least 12 months previously were compared with those of 25 healthy individuals. Urinary nickel, manganese and lithium excretion, and serum nickel, manganese and cadmium concentrations were statistically significantly lower for active stone patients compared to those with previous stone episodes and healthy individuals. No difference in the concentrations of trace elements could be found, however, for patients with previous stone episodes and healthy individuals. Nickel, manganese, lithium and cadmium could be of significance in the pathological mechanism of stone formation, not from mineralogical or crystallographic viewpoints but for the smooth flow of enzymatic reactions in biological systems.

Adult↗