Analysis of calculi by infrared spectroscopy in children from the Moroccan mid-Atlas region

Calculi from 45 Moroccan children aged between 2 and 15 years underwent morphological and infrared spectrometric analysis. The stones were three times more frequent in males than females (M/F = 3.09). Whewellite was the main component in 51.1% of cases and in 44.4% of stone nuclei, wheddellite in 8.9% of stones and nuclei, carbapatite in 6.7% of stones and 8.9% of nuclei, struvite in 15.6% of stones and 11.1% of nuclei. Ammonium hydrogen urate and uric acid were predominant respectively in 8.9% and 6.7% of stones and in 15.6% and 11.1% of nuclei. In addition to whewellite, struvite and ammonium hydrogen urate were the main components of bladder stones from both sexes. With respect to their calculi, whewellite was present in 84.4% of cases and wheddellite in 26.7%. Purines were present in 46% of calculi, especially as ammonium urate (28.9%) and uric acid (15.6%). Calcium phosphates as the main components were infrequent. In contrast, they were frequently identified in urinary calculi from children, respectively 64.4% and 40% for carbapatite and amorphous carbonated calcium phosphate.     

Infrared spectroscopic analysis of urinary stones (including stones induced by melamine-contaminated milk powder) in 189 Chinese children

Aim

The aim of the study was to investigate the composition of the stones in Chinese children with urolithiasis, including peculiar stones induced by melamine-contaminated milk powder.

Materials and Methods

Between 1999 and 2009, 189 urinary stones from children of East China were received at our institution. Among them, 12 stones were received from pediatric stone formers with a history of consuming melamine-contaminated milk powder in 2008; and the remaining stones were defined as “natural” stones. All stones were analyzed by Fourier transform infrared spectroscopy.

Results

Among 177 “natural” stones, whewellite stone (49.72%) was observed most frequently followed by weddellite stone (15.25%), uric acid anhydrous stone (9.6%), carbapatite stone (9.04%), cystine stone (9.04%), ammonium acid urate stone (4.52%), struvite stone (2.26%), and sodium urate stone (0.56%). Twelve young children who consumed melamine-contaminated milk powder were younger than 3 years, and their stones were composed of a mixture of uric acid dihydrate and ammonium acid urate based on Fourier transform infrared spectroscopy. In addition, the stones were radiolucent and could be dissolved by urine alkalinization.

Conclusions

Our study emphasizes the relatively high rate of calcium oxalate stones and cystine stones, and the relatively low rate of struvite stones in Chinese children with urolithiasis. The stones caused by melamine-contaminated milk powder are composed of the mixture of uric acid dihydrate and ammonium acid urate.     

Changes in stone composition according to age and gender of patients: a multivariate epidemiological approach

Urinary stone incidence and composition have changed markedly over the past half-century in industrialized countries, in parallel with profound changes in living standards and dietary habits, with a dramatic increase in the incidence of calcium oxalate stones. However, studies evaluating the influence of age and gender on the distribution of the various types of urinary calculi are scarce. We report the results of a study based on 27,980 calculi (from 19,442 males and 8,538 females) analyzed by infrared spectroscopy between 1976 and 2001. The relationships between age and sex and stone composition were investigated using a multivariate approach, based on correspondence factor analysis (CFA). We found a male predominance for calcium oxalate and uric acid, a female preponderance for calcium phosphate and struvite stones, and an increasing prevalence of uric acid stones with age in both genders. CFA was able to reconstruct in blind the age curve from stone composition. The first two axes of the multidimensional classification, which correspond to age, included 86.9% of the total variance, indicating that age was the main factor involved in stone type. Superimposition of age classes and stone components showed a strong relationship between age and whewellite, weddellite, brushite, carbapatite, octacalcium phosphate and uric acid, while other substances (whitlockite, amorphous carbonated calcium phosphate, struvite, proteins, mucopolysaccharides, triglycerides or ammonium urate) appeared weakly related to age. In addition, CFA suggests the role of common lithogenic factors between weddellite, carbapatite and brushite, which clustered in the same area, whereas the various crystalline forms of phosphate stones segregated into two different clusters, suggesting distinct pathogenic factors. In conclusion, this study provides a picture of the present epidemiology of urinary stones in France. CFA helped to confirm: (1) an etiopathogenic distinction between weddellite and whewellite, (2) etiopathogenic associations between chemical compounds, which were only suspected on a clinical basis, and (3) suggested yet unrecognized associations, especially with respect to the heterogeneous group of phosphate stones.     

Urolithiasis in Okinawa, Japan: A relatively high prevalence of uric acid stones

AIM: The aim of the present study was to investigate the composition of urinary tract stones in patients from Okinawa, the most southern island group of Japan. METHODS: The study was conducted by 12 hospitals in Okinawa. A total of 1816 urinary tract calculi were obtained from 1816 patients (1323 males; 493 females). The patients had a mean age of 53 +/- 15.3 years (mean +/- SD). The calculi were examined to determine their chemical composition. Stone samples were analyzed by computed infrared spectrophotometer. RESULTS: Pure stones comprised 58.4% of the total, with calcium oxalate stones accounting for 40% (21% monohydrate [whewellite]; 6.6% dihydrate [weddellite]; and 12.4% combined monohydrate and dihydrate stones), uric acid/urate stones for 9.6%, calcium phosphate stones for 5.1%, and struvite stones for 3.7%. The other 41.6% of the stones consisted of calcium oxalate mixed with other components. The male-to-female ratio was 2.7:1. CONCLUSION: In our series, calcium oxalate stones accounted for 81.6% of the urinary tract calculi, while uric acid/urate stones accounted for 15.8%. Uric acid stones, predominantly the anhydrous and/or dihydrate forms, showed a relatively high prevalence. Calcium oxalate stones, predominantly in the form of whewellite, showed a high prevalence among pure calculi; while the predominant combinations among mixed calculi were weddellite + calcium phosphate and whewellite + uric acid/urate.     

The incidence distribution and development of a trend of urinary stone substances. An evaluation of the data on over 210,000 urinary stone analyses from the area of the former DDR]

A computer analysis of more than 214,000 urinary stone analysis data recorded in 13 analysis centres in the GDR between 1970 and 1985 was performed. The relative frequencies of urinary stone constituents as pure substances and as main and secondary constituents were determined. Forty-eight percent of all calculi were monomineralic, and the sex ratio (male/female) was 1.96. In the so-called average calculus, mainly whewellite makes up 60.9% of its substance, weddellite 11.8%, uric acid 10.9%, apatite 4.76%, struvite 4.13%, ammonium urate 0.33%, and cystine 0.2%. Artefacts were found in 2.6% of the cases. Trend analysis shows a marked increase in the amount of whewellite and a reduction in the amounts or uric acid, struvite and cystine.     

Pediatric urolithiasis in Armenia: a study of 198 patients observed from 1991 to 1999

To study prospectively the risk factors and etiology of urolithiasis in all stone patients aged <15 years admitted from 1991 to 1999 to the Arabkir hospital in Yerevan. Stones were obtained by surgery (64%), extracorporeal shockwave lithotripsy (ESWL) (7%) or cystoscopic extraction (4%); 25% passed spontaneously. All were examined by infrared spectroscopy, and spot urines were analyzed chemically. 198 patients, 180 (68% males) with renal stones and 18 (83% males) with primary bladder stones, were studied. Calcium oxalate (CaOx) was the predominant constituent in 62% of the kidney stones, followed by struvite (17%), calcium phosphate (7%), uric acid (7%), ammonium acid urate (5%), and cystine (2%). Bladder stones contained CaOx in 72%, uric acid in 22% and ammonium acid urate in 6% of patients. Etiology was obviously metabolic in 5% and possibly metabolic in 26%. Twenty percent of stones were infectious, and 19% were endemic (9% bladder and 10% kidney stones); 4% were secondary to urinary stasis with malformation but no infection. Etiology in 26% remained unknown. Stone composition and metabolic etiology are similar to that in central Europe and North America. In contrast, infectious calculi and particularly endemic stones are still common, although becoming less so now. Urolithiasis in Armenia thus reflects the transition from a rural to an urban society. Received: 17 January 2001 / Revised: 24 April 2001 / Accepted: 24 April 2001     

The aetiological and clinical pattern of childhood urolithiasis in Saudi Arabia

The clinical and aetiological pattern in 85 stone-forming children presenting to an integrated nephrourological service in Riyadh is reviewed. All patients were below the age of 15 years, the male to female ratio being 2∶1. Only 2 children presented with bladder calculi. The remaining all had upper tract stone and, in 12 cases, these were bilateral. Of 34 calculi recovered for analysis, one-third was predominantly calcium oxalate and a further third was composed of uric acid or urate. Four patients had cystine stones and the remaining 7 presented mixed calcium stones, 6 (17.6%) being struvite and infection-related. Of the 85 patients 55 were treated successfully with extracorporeal shock wave lithotripsy, 16 underwent surgery and 7 had their stones removed by endourological procedures. In the remaining 7 children, stones dissolved or were passed spontaneously during medical therapy. Nine children (10.6%) showed a primary metabolic defect leading to their stone formation, 10 (11.8%) had a predisposing anatomical anomaly and 15 (17.6%) presented with urinary tract infection. Of the remaining 51 patients (60%) with idiopathic disease, 6 showed hypercalciuria on investigation and 2 children may have formed their stones due to prolonged recumbency.     

2015~2018年达州市尿路结石患者人口学特征及结石化学成分分析

目的对2015~2018年四川省达州地区尿路结石患者人口学特征及结石化学成分进行分析。方法选择2015年1月至2018年12月四川省达州市中西医结合医院进行治疗的583例尿路结石患者,经体外振动波碎石、手术、自排等方式获得结石标本583份进行研究。所有患者入组后均采集性别、年龄、居住地等一般资料,获取结石标本后以结石红外光谱自动分析系统对其化学成分进行分析。结果583例患者中单纯性结石289例(49.75%),二重混合性结石288例(49.40%),三重混合性结石6例(1.03%)。从结石成分分布上看草酸钙占比最高,为94.00%,其次是磷酸磷灰石37.04%、尿酸及尿酸铵14.92%。女性患者磷酸铵镁占比为4.31%,明显高于男性的1.35%(P<0.05)。其他成分不同性别患者分布情况差异无统计学意义(P>0.05)。60岁以下的患者结石成分为草酸钙占比为96.69%,明显高于60岁及以上者的89.55%(P<0.05)。其他成分不同年龄段患者分布情况差异无统计学意义(P>0.05)。城镇居民患者草酸钙、磷酸磷灰石占比分别为96.69%、40.38%,均明显高于农村居民的89.82%、28.74%(P<0.05)。其他成分不同居住环境患者分布情况差异无统计学意义(P>0.05)。结论四川达州地区尿路结石患者结石化学成分易草酸钙为主,其次为磷酸磷石灰石、尿酸及尿酸铵。不同性别、年龄、居住环境对尿路结石化学成分分布有一定的影响。     

The impact of contemporary bladder management techniques on struvite calculi associated with spinal cord injury.

OBJECTIVE: To evaluate the incidence, risk factors and complications of upper tract struvite calculi, often associated with spinal cord injury (SCI), as such patients have a high incidence of urinary infection complicating their neurogenic voiding dysfunction, by reviewing a large population of patients with SCI in whom modern techniques of bladder management were used. PATIENTS AND METHODS: Between 1982 and 1996, 1669 patients with SCI were admitted to our institution; 1359 of these patients sustained their injuries during the study period. During this time, their bladder management was based on urodynamic and imaging criteria, using techniques such as early intermittent catheterization, sphincterotomy and bladder augmentation where possible to create a catheter-free, low-pressure reservoir. All instances of upper tract struvite calculi in this population were documented. Risk factors for stone development, presentation and complications, management and recurrence rates were assessed. RESULTS: Over the 15 years, 58 patients (3.5% of the SCI population) were treated for a total of 144 episodes of struvite calculi. The incidence of stones in those injured since 1982 was 1. 5%; 67% of these patients had complete spinal cord lesions, 54% had lesions of the cervical cord and 53% developed their first stone >10 years after injury. Only 22% presented within 2 years of injury. The group of patients developing stones had a significantly higher incidence of indwelling catheters (49%), bladder stones (52%) and vesico-ureteric reflux (28%) than those who were stone-free. The development of recurrent urinary tract infections was the most common mode of presentation. The stone-free rate after treatment was 87%. Normal renal function was preserved in 72% of patients. CONCLUSIONS: In a large population of patients with SCI managed using contemporary bladder techniques the incidence of upper tract calculi was 3.5%; 30% of these stones were complete or partial staghorns. Those patients with complete cord lesions, permanent indwelling catheters and vesico-ureteric reflux were at the highest risk. Stone clearance was 87% and recurrent stones occurred in 69% of patients. Struvite renal calculi continue to be a significant problem in the spinal cord injury population.     

Ammonium acid urate calculi: a reevaluation of risk factors

PURPOSE: We reevaluate the demographic and metabolic risk factors for ammonium acid urate stones. MATERIALS AND METHODS: Since 1986, 23 women and 21 men ranging in age from 20 to 81 years (mean 48.7) were treated for stones partly composed of ammonium acid urate. Stone composition ranged from 2 to 60% ammonium acid urate (mean 24.1) of the total stone mass. No patient had a pure ammonium acid urate stone, although 11 (25%) had stones with ammonium acid urate as the predominant crystal. RESULTS: In the 44 patients 1 or more potential risk factors for ammonium acid urate were identified. Of the patients 11 (25%) had a history of inflammatory bowel disease with 10 (22.7%) having undergone ileostomy diversion, 6 (13.6%) admitted to a history of significant laxative use or abuse, 18 (40.9%) were morbidly obese, 16 (36.4%) had a history of recurrent urinary tract infections and 9 (20.5%) had a history of recurrent uric acid stones. CONCLUSIONS: Patients clearly at risk for stones with an ammonium acid urate component include those with a history of inflammatory bowel disease and ileostomy diversion or laxative abuse. Other factors that may potentially enhance ammonium acid urate stone formation include morbid obesity, recurrent uric acid calculi and recurrent urinary tract infection. A careful history followed by further metabolic evaluation is warranted in these patients.     

gamma-Carboxyglutamic acid, a component in human pediatric bladder stones containing calcium salts

The amino acid gamma-carboxyglutamic acid (Gla) has been previously detected in the vitamin K-requiring blood clotting factors, proteins of calcified vertebrate tissue, renal tissue, plasma protein C, ectopic calcifications, and calcium-containing renal calculi. This paper reports the presence of Gla in the EDTA-soluble, non-dialyzable material recovered from human pediatric bladder stones containing calcium salts. In bladder stones composed of calcium oxalate, uric acid and ammonium acid urate, 73 Gla residues per 1,000 amino acid residues were detected. Bladder stones composed of calcium oxalate, uric acid, ammonium acid urate, and hydroxyapatite contained 48 Gla residues per 1,000 amino acid residues present. No Gla was detected in the predominantly magnesium ammonium phosphate (struvite) bladder stones. These results with human bladder stones from children under 10 years of age are consistent with the observations from adult patients in which Gla was detected in the calcium-containing renal calculi but not in the non-calcium-containing renal calculi. The present study adds to the growing body of information concerning the possible role of Gla in normal and abnormal calcium metabolism.     

Characteristics of patients with staghorn calculi in our experience

PURPOSE: To elucidate the factors contributing to staghorn stone formation in patients. MATERIALS AND METHODS: The records of 82 patients (44 men and 38 women) with complete staghorn calculi were reviewed retrospectively for clinical presentation, metabolic disturbances and anatomical abnormalities. RESULTS: There were 79 unilateral and three bilateral cases. The patient performance of the activities of daily life was assessed with the modified Rankin scale (MRS) and it was found that 69 patients were functionally independent (84.1%, MRS 0-1) and 10 patients had a severe disability (12.2%, MRS 4-5). Seven patients had chronic indwelling catheters (8.5%). A positive urine culture was found in 24.4% of patients. Analysis of stone composition revealed magnesium ammonium phosphate and mixed calcium oxalate-phosphate were the most frequently identified types of stone (32.1% and 22.2%, respectively). Urinary pH was low in patients with uric acid stones (mean 5.4). Hyperuricemia, cystinuria and hypercalciuria were found in 14.6%, 2.4% and 37.8%, respectively. Hypercalciuria was found more frequently in calcium-stone cases. Eleven patients (13.4%) showed structural abnormalities of the kidney. CONCLUSIONS: Our data show that the patients with severe disability, urinary tract infection and hypercalciuria could be recognized more frequently in staghorn calculi compared with common urolithiasis. However, in Western countries, the frequency of both urinary tract infection and struvite stones is much higher than in our data. Other Japanese authors have also reported the low frequency of struvite stones in staghorn calculi, suggesting that various factors other than urinary tract infection possibly contribute to the formation of staghorn calculi in Japan.     

Crystalline phase differentiation in urinary calcium phosphate and magnesium phosphate calculi

Phosphates are encountered as the main components in about 15% of urinary calculi. Except for struvite, no specific correlations have been found between the crystalline phase of the phosphates and the cause of nephrolithiasis. OBJECTIVE: The relationship between aetiological factors and crystalline phases or carbonate rate in calcium phosphate stones were assessed. MATERIAL AND METHODS: From a series of 1148 phosphate calculi, we investigated the relationship between composition and aetiological factors. RESULTS: Carbapatite was the most frequent crystalline phase (74.0%). It was associated with many possible causes, including hypercalciuria, hypocitraturia, primary hyperparathyroidism, tubular acidosis, medullary sponge kidney and chronic urinary tract infection. The carbonate rate of carbapatite may be of clinical interest because carbonate rates above 15% are frequently related to urinary tract infection with urea-splitting bacteria. Conversely, the carbonate rate was commonly less than 10% in cases of carbapatite induced by metabolic disorders. Among other phosphates, brushite was found in hypercalciuric states and primary hyperparathyroidism and whitlockite in cases of urinary tract infection by non-urease-producing bacteria. CONCLUSION: Identification of crystalline phases and measurement of carbonate rate in calcium phosphate calculi is of clinical interest for identifying stone aetiology.     

广东东莞地区416例泌尿系结石成分分析

目的 应用红外光谱法测定东莞地区泌尿系结石化学成分,探讨本地区泌尿系结石患者的尿路结石成分特点,为本地区泌尿系结石的深化治疗、防止结石复发及预防提供科学依据.方法 收集经自行排出、碎石后排出或手术中取出的泌尿系结石标本416例,应用溴化钾压片技术的红外光谱法对其化学成分进行定性分析.结果 416例泌尿系结石患者中男性居多,占66.8%(278/416),女性占33.2%(138/416);上尿路结石占88.2%,下尿路结石(膀胱结石居多)占11.8%;结石成分定性分析共检测出一水草酸钙、二水草酸钙、碳酸磷灰石、无水尿酸、六水磷酸铵镁和尿酸铵6种化学成分.单一成分结石163例(一水草酸钙/无水尿酸/碳酸磷灰石/六水磷酸铵镁:98/56/6/3),占39.2%;混合成分结石253例,占60.8%,其中以草酸钙和碳酸磷灰石的混合结石为主(188/253).所有结石标本中草酸钙检出率最高,占80.5%(335/416),其次为碳酸磷灰石(49.3%)及无水尿酸(17.3%);膀胱结石成分以一水草酸钙或无水尿酸为主.结论 东莞为全国泌尿系结石最高发地区,其结石成分以草酸钙和碳酸磷灰石为主,单一成分结石亦占相当比例.尿路结石成分分析对了解结石成因可提供重要的线索,对临床制定个性化治疗方案、预防结石形成及复发具有重要意义.     

Dual-energy computed tomography for the differentiation of uric acid stones: ex vivo performance evaluation

We assessed the potential of dual-energy computed tomography (CT) for the differentiation between uric acid (UA)-containing and non-UA-containing urinary stones. Forty urinary stones of 16 different compositions in two sizes (< and >/= 5 mm) were examined in an ex vivo model. Thirty stones consisted of pure calcium oxalate (whewellite or wheddellite), calcium phosphate (apatite, brushite, or vaterite), ammonium magnesium phosphate (struvite), UA, ammonium acid urate, ammonium phosphate, sodium hydrogen urate, or cystine, and ten stones were of mixed composition (UA-sodium hydrogen urate, whewellite-urate, wheddellite-urate, whewellite-brushite, or whewellite-brushite-struvite). Scans were performed using dual-source CT in a dual-energy mode with the tubes simultaneously operating at 80 and 140 kV. Two readers analysed the data with respect to stone attenuation at each energy level. The stones were classified as UA- or non-UA-containing using manual attenuation measurements and software analysis results. Sensitivity, specificity, PPV, and NPV were calculated using crystallographic stone analysis as the gold standard. Twenty-six out of 40 stones (65%) contained no UA; 14 stones (35%) contained UA. When compared with UA-containing stones, the differences in attenuation values at 80 and 140 kV were significantly (P < 0.001) higher in stones containing no UA. The software automatically mapped 39/40 stones (98%). Only one (2%) 2 mm UA-stone was missed. The software correctly classified all detected stones as UA- or non-UA-containing. The attenuation values of the missed stone were manually plotted into the analysis sheet which allowed for the correct classification of the stone (containing UA). Therefore, the sensitivity, specificity, PPV, and NPV for the detection of UA-containing stones was 100%. Ex vivo experience indicates that differentiation between UA- and non-UA-containing stones can be accurately performed using dual-source dual-energy CT.     

结石红外光谱自动分析系统在尿路结石成分分析中的应用

目的 评价红外光谱自动分析系统检测尿路结石成分的临床应用价值.方法 尿路结石标本1450例.男1032例,女418例.年龄6个月～88岁.男性平均年龄(41.7±15.3)岁,女性(42.0±15.6)岁.肾结石875例(60.34%),输尿管结石504例(34.76%),膀胱结石71例(4.90%).均采用LIIR型结石红外光谱自动分析系统分析.解析结果均行红外光谱人工解析验证,必要时辅以偏光显微镜、X线衍射或化学方法进行验证. 结果在结石总体构成比上,一水草酸钙结石714例(49.24%),碳酸磷灰石结石444例(30.62%),无水尿酸结石93例(6.41%),二水草酸钙结石92例(6.34%),六水磷酸铵镁结石28例(1.93%),胱氨酸结石23例(1.59%),尿酸铵结石20例(1.38%),二水尿酸结石16例(1.10%),二水磷酸氢钙结石12例(0.83%),一水尿酸钠结石2例(0.14%),碳酸钙结石1例(0.07%),其他5例(0.34%).结石的组合成分上,混合性结石1053例(72.62%),单一成分结石仅397例(27.38%).混合性结石主要为含钙类结石.其中15例婴幼儿结石为食用三聚氰胺污染奶粉所致,成分为二水尿酸与尿酸铵的混合结石.验证结果表明,结石主要成分误检6例(0.41%),将无水尿酸误检为尿酸铵或碳酸磷灰石;漏检9例(0.62%),其中漏检六水磷酸铵镁或碳酸磷灰石7例,性质不明2例.在2种和3种成分的混合性结石中,含量相对低的成分各漏检6例和10例,均为六水磷酸铵镁或碳酸磷灰石. 结论结石红外光谱自动分析系统分析尿路结石成分具有准确、自动、快捷等优点,适合临床常规使用.

Abstract：

Objective To determine the value of applying LIIR Automatic Analysis System of Infrared Spectroscopy in analyzing urinary stone composition. Methods 1450 samples of urinary stones were collected from 1032 male and 418 female patients. The age of patients ranged from 6 months to 88 years. The mean ages were 41.7±15.3 and 42.0±15.6 years for male and female patients, respectively. Of 1450 stones, 875 cases were located in kidney (60.34%), 504 cases in ureter (34.76%) and 71 cases in bladder (4.90%). All stones were analyzed by LIIR Automatic Analysis System of Infrared Spectroscopy (Tianjin). Analysis results were reevaluated by the artificial analysis of spectrogram, if necessary, with polarization microscope, chemical analysis, and X-ray diffraction.Results Calcium oxalate monohydrate stones were found in 714 cases (49. 24%), carbonate apatite stones in 444 cases (30.62%), anhydrous uric acid stones in 93 cases (6.41%), calcium oxalate dihydrate stones in 92 cases (6. 34 % ), ammonium magnesium phosphate hexahydrate stones in 28 cases (1.93%), cystine stones in 23 cases (1.59%), ammonium urate stones in 20 cases (1.38%), uric acid dihydrate stones in 16 cases (1.10%), brushite stones in 12 cases (0.83%), sodium urate monohydrate stones in 2 cases (0. 14%), calcium carbonate stones in 1 cases (0. 07%), and other stone types in 5 cases (0. 34%). Most urinary stones were composed of 2 or more compositions, and pure stones were only observed in 397 cases (27.38%). Most of the mixed stones contained calcium and non-calcium mixed stone was rarely observed. In addition, 15 stones were found in infants who had consumed melamine-contaminated milk powder. These stones were composed of uric acid dihydrate and ammonium urate. The results of reevaluation by artificial analysis showed the following: among pure and mixed stones, false detection occurred in 6 cases (0.41%), of which the composition was ammonium urate or carbonate apatite determined by automatic system but the true composition was anhydrous uric acid. False negative detection occurred in 9 cases (0.62%), of which the composition was ammonium magnesium phosphate hexahydrate or carbonate apatite in 7 cases, but in other 2 cases the composition could not be determined by artificial analysis. The false negative detection of components with relatively low content occurred in 6 cases and 10 cases in stones with 2 components and 3 components, respectively. The undetected composition in these cases was ammonium magnesium phosphate hexahydrate or carbonate apatite. Conclusion Automatic Analysis System of Infrared Spectroscopy has many advantages in accuracy, automation and is quick in analyzing the composition of urinary stones, and is worthy of promotion in clinical use.     

Infrared spectroscopic analysis of 5,248 urinary stones from Chinese patients presenting with the first stone episode

A series of 5,248 urinary stones was analyzed by Fourier transform infrared spectroscopy between 1999 and 2008. This study evaluated the percentage of each stone type and the association with sex and age in Chinese stone formers presenting with the first stone episode. The overall sex ratio (male:female) was 2.34:1. Results showed that the preponderant type of stone was calcium oxalate, followed by carbapatite, anhydrous uric acid, struvite and cystine. Struvite stones in this study accounted for a relatively low rate compared to that reported by others. Of 5,248 stones, only 38.1% had one component, 42.5% consisted of two components, and 20.4% consisted of three components. Our results also showed the higher percentage of carbapatite stones in females than in males and the increment of anhydrous uric acid stones with age. In addition, the percentage of calcium oxalate stones decreased with increase in the percentage of carbapatite stones over the period.     

Giant urinary tract calculi: A case series

Background: A giant urinary tract calculus is not common in modern urological practice. The bladder has been known to harbour very large stones, weighing hundreds of grams, some with bearable symptoms, for a long time. These giant stones account for less than 1% of all urinary tract calculi. The aim of the present report is to highlight our management of a series of giant urinary tract calculi. Methods: A series of 14 patients were seen over 5 years (2004–2009) with giant urinary tract calculi and were studied in detail using their hospital records. Their biodata, clinical presentation, presence of urinary tract obstruction or infection, diagnostic investigations, operative management, and physical and chemical characteristics of the calculi were reviewed. Results: There were 13 males and one female, and their ages ranged between 4 and 79 years (median 30.5). Ten patients had bladder calculi, one ureteric in combination with a staghorn renal calculus, a second stone in the urethra and two huge staghorn calculi in non‐functioning kidneys. The mean weight of the calculi was 153.3 ± 69.6 (range 25–300 g) and the chemical compositions were mainly calcium oxalate, struvite (triple phosphate) and calcium carbonate. All the stones were radio‐opaque and two were associated with non‐functioning kidneys, and there was no congenital anatomical defect causing obstruction in any of the patients. Conclusion: Giant urinary tract calculi are most common in the male urinary bladder and are managed by open surgery with very good outcome. There were no anatomical abnormalities causing narrowing in the urinary tract in any of the cases.     

Mineral composition of 103 stones from Iran

The mineral composition of 103 stones from Iran was determined by a polarisation microscope and infrared spectroscopy. The commonest components were whewellite (81.5%), weddellite (40.7%), apatite (69%) and ammonium acid urate (24.4%). Ectopic cossification in the nuclei was found in three renal calculi (2.9%). Twenty-five stones were from children, where one of the most frequent patterns was formed by both ammonium acid urate and calcium oxalate. This suggests that a high proportion of the children from Iran with urolithiasis have nutritional disorders.     

232例湖北地区泌尿系结石红外光谱成分分析

目的：分析湖北地区泌尿系结石化学成分的构成,为本地区结石的防治提供依据。方法：采用结石红外光谱自动分析系统对2011年11月～2012年8月期间收集到的湖北地区泌尿系结石232例进行成分分析。结果：232例结石中,各成分的检出率为：一水草酸钙（COM）85．34％,二水草酸钙（COD）62．93％,碳酸磷灰石（CA）24．14％,无水尿酸（UA）12．93％,二水磷酸氢钙（PH）4．31％,磷酸铵镁（MAP）6．90％,黄嘌呤1．29％,胱氨酸（CYS）1．29％,方解石0．86％,尿酸铵（AU）0．86％。含草酸钙成分结石86．21％,含磷酸钙成分结石28．45％,含磷酸铵镁成分结石6．90％,含尿酸成分结石13．79％,含胱氨酸成分结石1．29％。混合成分结石181例（78．02％）,尿路结石发病男性多于女性,男女比例为3．14：1。结论：湖北地区泌尿系结石以混合性结石为主,COM检出率最高,其次为COD。结石成分分析对于结石的防治有重要意义。