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Crystalluria, characterized by the formation of calcium oxalate crystals, is a common urinary disorder. While increasing urinary volume is a traditional approach to manage this condition, novel therapeutic strategies are being explored. Lemon juice (LJ), rich in citric acid, is of particular interest due to its calcium ion chelating properties. This study evaluated the in vitro potential of LJ to inhibit calcium oxalate crystal formation. Using specialized electrodes (CPE-GC) and various electrochemical techniques (SWV, CV, LV, EIS), we characterized the interactions between LJ and calcium ions. Our findings, obtained from a simplified model using calcium carbonate, demonstrate the ability of LJ to effectively complex calcium ions, thereby reducing their availability for crystal formation. Although these results are promising, it's important to note that the experimental conditions do not fully replicate the complexity of physiological urine. In vivo studies are therefore necessary to confirm the efficacy of LJ in a clinical setting. In conclusion, lemon juice appears to be a promising approach for preventing calcium oxalate crystal formation. Its mechanism of action, based on calcium ion chelation, offers an alternative to conventional treatments. However, further research is required to evaluate its clinical efficacy and optimize its usage. [ABSTRACT FROM AUTHOR]

Introduction: Crystalluria is an important indicator of renal stone recurrence. Mechanisms underlying urinary stone formation are still not fully understood and raising interests has been giving to intestinal commensal bacteria for their contribute in maintaining urinary solutes equilibrium. The aim of our phase II study was to examine the administration of potassium citrate, magnesium and probiotics in order to reduce crystalluria. Materials and Methods: Since May 2021, we enrolled 23 patients candidates for ureterorenolithotripsy for calcium oxalate kidney stones with crystalluria and a normal metabolic profile. The analysis was validated by the Institution's Ethical Committee (no. approval STS CE Lazio 1/N-823). At discharge, patients were provided with daily food supplementation for 20 days of 1 billion Lactobacillus paracasei LPC09, 1 billion Lactobacillus plantarum LP01, 1 billion Bifidobacterium breve BR03, potassium (520 mg), citrate (1400 mg), and magnesium (80 mg). Crystalluria was re-assessed at 1, 3, 6, and 12-months follow-up by polarized light microscopy. Results: After one month from the oral supplementation, no patient reported crystalluria; at 3 months, among the 20 participants available for re-evaluation, still no patient reported crystalluria. Instead, crystalluria was reported in three patients (15%) at 6 months, and in five patients (25%) at 12 months follow-up. Conclusions: The oral supplementation with Lactobacillus spp. and Bifidobacterium spp. was found able to reduce the prevalence of crystalluria in a cohort of patients with diagnosis of calcium oxalate kidney stones with crystalluria candidate to ureterorenolithotripsy. [ABSTRACT FROM AUTHOR]

This study aimed to assess the ability of rosmarinic acid (RA) to prevent kidney stone formation in an ethylene glycol and ammonium chloride (EG/AC) model. There was an increase in diuresis in the normotensive (NTRs) and hypertensive rats (SHRs) treated with hydrochlorothiazide (HCTZ) and exposed to EG/AC, while RA restored urine volume in NTRs. The EG/AC groups exhibited lower urine pH and electrolyte imbalance; these parameters were not affected by any of the treatments. Both HCTZ+EG/AC and RA+EG/AC reduced calcium oxalate crystal formation in NTR and SHR urine. Kidney tissue analysis revealed alterations in oxidative stress and inflammation parameters in all EG/AC-receiving groups, with RA enhancing antioxidant defenses in SHRs. Additionally, crystals were found in the kidney histology of all EG/AC-exposed groups, with reduced Bowman's capsule areas in NTRs and SHRs. The NTR VEH+EG/AC group showed intense renal damage, while the others maintained their structures, where treatments with HCTZ and RA were fundamental for kidney protection in the NTRs. Docking analysis showed that RA exhibited good binding affinity with matrix metalloproteinase-9, phosphoethanolamine cytidylyltransferase, and human glycolate oxidase enzymes. The data disclosed herein underscore the importance of further research to understand the underlying mechanisms better and validate the potential of RA for clinical use. [ABSTRACT FROM AUTHOR]

The present study was conducted on 56 cats (49 males and 7 females) who presented with signs of feline lower urinary tract disease (FLUTD). Abdominal radiographs and ultrasounds, urinalysis, bacterial culture, and stone analysis were performed. Serum blood urea nitrogen (BUN) and creatinine were investigated. Urine sample analysis was investigated microscopically. The results indicated that the most common causes of lower urinary tract affections were urolithiasis (37.5%), followed by feline idiopathic cystitis (FIC) (33.9%), bacterial urinary tract infection (UTI) (14.2%), urethral plugs (10.7%) and neoplasia (3.5%). Urethral obstruction was (42.8%) more frequent in cats with urolithiasis, urethral plugs and FIC. Cats with FIC and urethral plugs were significantly younger than other diagnostic groups. Cats with urolithiasis and neoplasia had higher body weights than other FLUTD groups. Persian cats (39.5%) were the most affected breed. The mineral compositions in the analyzed uroliths were calcium oxalate (62.5%), struvite (50%) and ammonium urate (25%). FLUTD urine sediment crystalluria were triple phosphate struvite crystals (51.7%), calcium oxalate crystals (16.0%), and ammonium urate crystals (12.5%). FIC, urethral plugs and urolithiasis showed a significant increase in crystalluria and urethral obstruction. Urethral obstruction represented 42.8%, and it occurred frequently in cats with urolithiasis, urethral plugs and FIC. Post-renal azotemia with increased BUN and creatinine concentrations was detected in obstructive urolithiasis, urethral plugs and FIC. The identified bacterial cultures included Escherichia coli (37.5%), Staphylococcus aurous (37.5%) and Proteus species (25%). The results obtained from the study indicate that age, breed, sex and indoor confinement represent real challenges in developing lower urinary tract affections. [ABSTRACT FROM AUTHOR]

Lower urinary tract problems were increasingly encountered in small animal practice. Urinary stones and crystals are common problems in these cases and are still a problem in cats and dogs. Dilution of urine or restriction of mineral intake is a way to reduce urolithiasis/crystalluria. Viburnum Opulus was prescribed as anti-urolitiatic in human medicine. The objective of this study was to evaluate the efficacy of Viburnum Opulus in urolithiasis or crystalluria in companion animals. For this purpose, 42 animals were presented with urinary system problems and diagnosed with urolithiasis or crystalluria, which were included in the study and divided into two main groups (21 calcium oxalate, 21 struvite) and two subgroups (Control and Study). The urinary score was noted as the presence of pollakiuria, crystals in the microscopic examination, hematuria, stranguria, proteinuria, leucocytes, and blood in the urine. The mean ages were 3.81 and 3.95 for the calcium oxalate and struvite groups, respectively. It was determined that the clinical urinary score of the calcium oxalate control group was 11.39 before the treatment and increased to 14.06 at the end of 2 weeks. However, it was observed that this score decreased from 10.71 to 8.71 in the calcium oxalate study group. In calcium oxalate-diagnosed animals, a decrease in clinical scores was significant in the Viburnum opulus group than in controls. The urinary scores decreased in both struvite subgroups, but no statistical differences were determined. All animals except the calcium oxalate control group were clinically healthy at the second visit. Using Viburnum opulus as an integrative medical approach will provide safe and effective treatment for urolithiasis/crystalluria. [ABSTRACT FROM AUTHOR]

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Background: Carbonated beverages are very popular worldwide. Carbonated beverage consumption vast increase raises great health concerns regarding their effect on calcium homeostasis besides obesity and renal function. Carbonated beverages sugar content, caffeine, and acidulant all can affect in a way or another calcium absorption, metabolism and excretion. The latter has direct effect on teeth, bone and general wellbeing. This study aims to reveal the effect of sub-chronic intake of carbonated beverage on urinary pH, crystalluria, calcium excretion. Methods: 21 healthy volunteers have been recruited in this study (9 males and 12 females) abstain for any carbonated beverages for at least the previous 4 weeks before participating in this study. Urine has been collected over 24 hours, the next day each volunteer has to drink 250 ml of carbonated beverage (Pepsi®) daily for 3 weeks. On the last day, urine was collected again over 24hr. pH, crystalluria, and calcium in urine have been measured. Results: Urine pH and crystalluria after 3 weeks' intake of 250 ml of carbonated beverage did not statistically differ from urine pH before the intake. Although, there was a trend toward reduction in pH and an increase in crystalluria. Total calcium excretion in urine increase was statistically significant when compared with calcium excretion at the study beginning. Conclusion: The regular intake of carbonated beverage (Pepsi®) increase calcium excretion. Thus, it may be advisable to increase the intake of milk or other dairy product to overcome the adverse impact of carbonated beverages. [ABSTRACT FROM AUTHOR]

A 5-y-old female bottlenose dolphin (Tursiops truncatus) from an aquarium in Japan had clinical signs of anorexia, vomiting, and bradykinesia. Enrofloxacin and lactated Ringer solution were administered for treatment of bacterial infection and for rehydration. Elevations of creatine kinase and aspartate aminotransferase activities were detected on day 4 of treatment, indicating that rhabdomyolysis had developed on day 3. On day 5, serum creatinine and urea concentrations increased and remained high throughout the remaining treatment; the dolphin died on day 16. Postmortem examination revealed massive necrosis of the longissimus dorsi muscles. Histologic examination revealed extensive necrosis of skeletal myofibers, multifocal renal tubular necrosis with intratubular casts and crystals, and suppurative bronchopneumonia. The renal casts labeled positively with anti-myoglobin antibody; expression of aquaporin-1 was decreased in renal tubules compared to normal kidney tissue. To our knowledge, this description of clinicopathologic findings of rhabdomyolysis leading to acute kidney injury with concomitant crystalline nephropathy has not been reported previously in a bottlenose dolphin. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the relationship between urinary stone type and the type of crystals in the urine. Patients and Methods: This retrospective study involved 485 patients with urinary stones treated at King Saud University Medical City from May 2015 to June 2017. Clinical data were obtained from medical records. Different statistical analysis methods were applied, including basic contingency analysis, analysis of variance, logistic regression, discriminant analysis, partition modeling, and neural network evaluations. Results: Of 485 patients, 47 had crystals detected by urinalysis. The most common type of crystal was calcium oxalate (n = 31), which had the highest association with calcium oxalate stones. Uric acid crystals (n = 8) were associated with uric acid stones. The neural network model used for determining the sensitivity and specificity showed an R-square value of 0.88, with an area under the curve of 0.94 for calcium oxalate, 0.94 for carbonate apatite, and 1.0 for uric acid. Conclusion: The predictive algorithm developed in the present study may be used with a patient's clinical parameters to predict the stone type. This approach predicts the stone types associated with certain patient characteristics with a high sensitivity and specificity, indicating that the models may be a valuable clinical tool in the diagnosis, management, and monitoring of stone diseases. [ABSTRACT FROM AUTHOR]

Objectives Nicaraguan sugarcane workers, particularly cane cutters, have an elevated prevalence of chronic kidney disease of unknown origin, also referred to as Mesoamerican nephropathy (MeN). The pathogenesis of MeN may include recurrent heat stress, crystalluria, and muscle injury with subsequent kidney injury. Yet, studies examining the frequency of such events in long-term, longitudinal studies are limited. Methods Using employment and medical data for male workers at a Nicaraguan sugarcane company, we classified months of active work as either work as a cane cutter or other sugarcane job and determined occurrence of dysuria, heat events and muscle events. Work months and events occurred January 1997 to June 2010. Associations between cane cutting and each outcome were analyzed using logistic regression based on generalized estimating equations for repeated events, controlling for age. Results Among 242 workers with 7257 active work months, 19.5% of person-months were as a cane cutter. There were 160, 21, and 16 episodes of dysuria, heat events, and muscle events, respectively. Compared with work months in other jobs, cane cutting was associated with an elevated odds of dysuria [odds ratio 2.40 (95% confidence interval 1.56-3.68)]. The number of heat and muscle events by cane cutter and other job were limited. Conclusions Working as a cane cutter compared with other jobs in the sugarcane industry was associated with increased dysuria, supporting the hypothesis that cane cutters are at increased risk of events suspected of inducing or presaging clinically evident kidney injury. [ABSTRACT FROM AUTHOR]

The Consensus Group deliberated on a number of questions concerning urine and stone analysis over a period of months, and then met to develop consensus. The Group concluded that analyses of urine and stones should be routine in the diagnosis and treatment of urinary stone diseases. At present, the 24-h urine is the most useful type of urine collection, and accepted methods for analysis are described. Patient education is also important for obtaining a proper urine sample. Graphical methods for reporting urine analysis results can be helpful both for the physician and for educating the patient as to proper dietary changes that could be beneficial. Proper analysis of stones is also essential for diagnosis and management of patients. The Consensus Group also agreed that research has shown that evaluation of urinary crystals could be very valuable, but the Group also recognizes that existing methods for assessment of crystalluria do not allow this to be part of stone treatment in many places. [ABSTRACT FROM AUTHOR]

In February 2018, a 2-year-old American shorthair was treated conservatively for cystitis caused by crystalluria. However, as long as drug withdrawal was proceeding, the condition would be repeated, and the condition worsened since August. In order to diagnose and treat the sick cat, clinical examination, laboratory examination, X-ray, B-type ultrasound and other methods were used for diagnosis, and treatment was conducted according to the diagnosis results. The results showed that the cat was caused by ammoniomagnesium phosphate crystals blocking urethra, complicated with postrenal azotaemia and hyperkalemia. The relapse continued after conservative treatment, and the cat finally recovered by modifying urethra surgically. The results showed that the deficiency of drinking water, the change of urine pH, and high dietary magnesium and fiber content could promote the occurrence of the disease. For the problem of urethral obstruction that could not be solved by conservative treatment, operation was done to modify urethral stricture. [ABSTRACT FROM AUTHOR]

Background: canine urine is a complex fluid produced via glomerular filtration; it is useful for the elimination of waste substances. However‚ under specific physiological conditions certain minerals become supersaturated‚ leading to the precipitation of salts‚ resulting in crystalluria. These crystals may aggregate and form solid concretions‚ known as calculi or uroliths. The development and formation of these crystals are influenced by several risk factors‚ including breed‚ size‚ gender‚ age‚ diet‚ and urinary tract infections. Objective: to determine the prevalence of urinary crystals in canines and their association with risk factors in Santa Rosa de Cabal (SRC) and the metropolitan area of Pereira (MAP) (Risaralda‚ Colombia). Methods: a retrospective study was conducted using 3038 urinalysis results from dogs located in SRC and the MAP in Risaralda‚ analyzed by a reference laboratory in Pereira (EJELAB®) over a period of four years. The results were categorized based on breed‚ age‚ and gender. Statistical analysis includes a cross- tabulation‚ chi-square‚ Fisher’s exact test‚ and logistic regression to determine the prevalence (95 % CI) of urinary crystals and assess their association with various risk factors. Results: a 48.5 % (95 % CI = 46.7- 50.2) of the samples exhibited some crystalluria‚ with a nearly equal distribution between females (50.1 %) and males (49.9 %). Of these‚ 25 % were of mixed breed. Struvite crystals were found to be the most prevalent (78.5 %)‚ followed by oxalates (14.4 %) and urate (5.3 %). On average‚ females had a higher urinary pH level (7.49) than males (7.36). An increase of 1 pH unit was associated with a 12.24 times higher risk of developing struvite crystals. In addition‚ oxalates were related with the size of the dog‚ miniature breeds showed a higher risk‚ There was no association found between crystalluria and the factors of urine density and age. Conclusions: the estimated prevalence of crystalluria was considered high (48.5 %)‚ with struvite being the most common type of crystal. Finally‚ both the pH‚ and the size of the dog were identified as risk factors for crystal formation‚ with pH being the main factor. [ABSTRACT FROM AUTHOR]

BACKGROUND: Struvite crystals (Magnesium Ammonium Phosphate) are one of the most common causes of urolith formation in cats. Presence of these crystals in urea leads to urinary obstruction and idiopathic cystitis. The prevalence of urinary crystals has increased in recent years, thus there has been a growing interest in development of noninvasive, fast responsive therapies. Vitamin C is a safe compound with antioxidant properties. This vitamin is known as urine acidifier as well. Since struvite crystals are more soluble in acidic pH, it could be expected that vitamin C application could improve crystals dissolution as well as their disposal. It could also prevent other complications. OBJECTIVES: This study was designed to analyze the effects of vitamin C in reducing the rate and intensity of struvite crystals with current long term therapies such as diet alteration, acidifier's applications and diuretics. METHODS: Ten male domestic cats with clinical signs of lower urinary tract disease were selected. Struvite crystalluria was confirmed by urine analysis and ultrasonography. Cats were divided to treatment and control groups each containing 5 cats. Both groups were treated by conventional therapies for two weeks, however, during the 1st week the treatment group received injectable vitamin C (100 mg/kg, every 24h, SC) and the control group received oral DL Methionine (200mg/cat, every 8h), in addition to conventional therapies. Urine was collected at days 0, 7 and 14 and its pH, specific gravity and number of crystals were calculated. Presence of floating echogenic foci was evaluated using ultrasound. RESULTS: Significant decrease in struvite crystalluria was observed in both groups. However, in group treated by vitamin C this decrease was faster and more effective. In addition, in case of obstruction, vitamin C showed better therapeutic effects. CONCLUSIONS: According to these results, vitamin C injection could be a therapeutic approach in treatment of urinary tract obstructions where fast response is needed to avoid further complications. Oral methionine seems to be a suitable choice for prophylaxis in patients with moderated signs and relatively high urine pH or continuing therapy to prevent recurrence of disease. [ABSTRACT FROM AUTHOR]

Dietary oxalate is plant-derived and may be a component of vegetables, nuts, fruits, and grains. In normal individuals, approximately half of urinary oxalate is derived from the diet and half from endogenous synthesis. The amount of oxalate excreted in urine plays an important role in calcium oxalate stone formation. Large epidemiological cohort studies have demonstrated that urinary oxalate excretion is a continuous variable when indexed to stone risk. Thus, individuals with oxalate excretions >25 mg/day may benefit from a reduction of urinary oxalate output. The 24-h urine assessment may miss periods of transient surges in urinary oxalate excretion, which may promote stone growth and is a limitation of this analysis. In this review we describe the impact of dietary oxalate and its contribution to stone growth. To limit calcium oxalate stone growth, we advocate that patients maintain appropriate hydration, avoid oxalate-rich foods, and consume an adequate amount of calcium. [ABSTRACT FROM AUTHOR]

The article examines whether Orbitrap, a high-resolution mass spectrometry (HRMS), can be used as an alternative method for the identification of amoxicillin crystalluria. It notes that administration of amoxicillin, especially in patients requiring high doses, can lead to crystalluria. It suggests alkalization of urine and increased fluid intake as a preventive measure.

References 1 Sand, TE, Jacobsen, S. Effect of urine pH and flow on renal clearance of methotrexate. Keywords: crystalluria; mass spectrometry; methotrexate EN crystalluria mass spectrometry methotrexate e165 e167 3 03/13/21 20210401 NES 210401 To the Editor, A 56-year-old man with psoriatic arthritis was prescribed oral methotrexate (15 mg each week every Sunday at around 13:00 UTC). Crystalluria, mass spectrometry, methotrexate. [Extracted from the article]

Urine sediment examination was performed in 150 samples of different animal species, out of which 120 samples showed abnormal constituents. The conditions recorded were cylindruria, crystalluria, urolithiasis, hematuria, hemoglobinuria, pyuria, bacteriuria and neoplasia. Urine sediment examination was found to be an important non-invasive tool for diagnosis of metabolic diseases and urinary tract pathology. [ABSTRACT FROM AUTHOR]

Background/Aim: Type 2 diabetes mellitus (T2DM) has been implicated as a risk factor for nephrolithiasis. The aim of this study was to determine the prevalence and types of crystalluria among individuals with T2DM. It further sought to identify associated risks, which could influence crystalluria. Methods: A case–control study with random sampling of 165 diabetes patients (cases) and 40 healthy non-diabetics (controls) was conducted from December 2012 to May 2013 at the Agona Swedru Municipal Hospital, Ghana. Sociodemographic and anthropometric data were obtained from the participants. Blood and urine samples were collected for the estimation of blood glucose (fasting) and urinalysis for the presence of crystals, respectively (light microscopy). Results: Overall frequency of crystalluria was 18.0%. The prevalence of urine crystals in diabetics (17.5%) was more than that in non-diabetics (5.0%). Types of crystals found in the T2DM patients by prevalence were calcium oxalate (12.7%), uric acid (3.6%), and tyrosine (1.2%). Mean age, body mass index, systolic blood pressure, and fasting blood glucose (FBG) were higher among case participants than in controls (P < 0.001; P < 0.001; P = 0.018; P < 0.001). Case participants had a lower urine pH than the controls (P < 0.001). Crystalluria was positively correlated with FBG (P = 0.002) and negatively with urine pH (P = 0.108). On multivariate analysis, FBG was independently associated with crystalluria (P = 0.002), after adjustment for other factors. Conclusion: Crystalluria is common in diabetes patients. Acidic urine pH is mostly seen in T2DM and may be a predisposing factor to crystalluria. Good glycemic control may be a helpful in reducing the occurrence of crystalluria among T2DM. [ABSTRACT FROM AUTHOR]

Objectives: It is estimated that 29% of patients treated with sulfadiazine ultimately develop acute kidney failure. Diagnosis is based on urine sediment analysis. Case presentation: A71-year-oldwomanwith loss of visual acuity in the context of a flare of systemic erythematosus lupus (SEL). A diagnosis of acute retinal necrosis was established, pending etiological confirmation. Empirical treatment with sulfadiazine was initiated. Follow-up analyses included urine sediment, which revealed pH 6, 30-50 RBCs/field, urothelial cells and lower tract epithelial cells, hyaline casts, fatty casts or Maltese cross, and abundant sulfadiazine crystals. The findingwas reported to the Unit of Nephrology, and treatment was immediately suspended. Conclusions: Sulfadiazine is an antibiotic of the family of sulfamides. Crystalization of sulfadiazine in the renal tubules may cause acute interstitial nephritis. These crystals adopt different shapes according to the metabolite that crystalizes: unaltered forms precipitate into dense, globular crystals, whereas in other cases, as in the case reported in this paper, crystals adopt a fan-shaped, shocks-of-wheat morphology. [ABSTRACT FROM AUTHOR]

Drug induced kidney injury is a frequent adverse event which contributes to morbidity and increased healthcare utilization. Our current knowledge of drug induced kidney disease is limited due to varying definitions of kidney injury, incomplete assessment of concurrent risk factors and lack of long term outcome reporting. Electronic surveillance presents a powerful tool to identify susceptible populations, improve recognition of events and provide decision support on preventative strategies or early intervention in the case of injury. Research in the area of biomarkers for detecting kidney injury and genetic predisposition for this adverse event will enhance detection of injury, identify those susceptible to injury and likely mitigate risk. In this review we will present a 6R framework to identify and mange drug induced kidney injury - risk, recognition, response, renal support, rehabilitation and research. [ABSTRACT FROM AUTHOR]

Crystalluria is a marker of urine supersaturation with substances deriving from metabolic disorders, inherited diseases or drugs. The investigation of crystalluria must be done according to a protocol which includes the delivery to the laboratory of a proper urine sample, the use of a microscope equipped with polarized light, the accurate knowledge of urine pH, and a comprehensive examination of the crystals, which is based on their identification, quantification and size measurement. For unusual crystals, infrared spectroscopy may also be needed. The main urinary crystalline categories include: calcium oxalates, calcium phosphates, uric acids and urates, struvite, aminoacids (cystine), purines (2,8-dihydroxyadenine and xanthine) and drugs (e.g. sulfamethoxazole, amoxycillin, ceftriaxone, atazanavir). The investigation of crystalluria is a cheap and valuable tool for the detection and the monitoring of inherited and acquired diseases associated with urinary stone formation or renal function impairment - either acute or chronic - due to intrarenal crystal precipitation. [ABSTRACT FROM AUTHOR]

We report a case of acute kidney injury (AKI) induced by amoxycillin crystalluria suggested by massive amounts of urinary crystals of unusual morphology. This hypothesis was further reinforced by a particular solubility pattern when the urine sample was exposed to various temperatures, alkali, acids and alcohol. We therefore suspended amoxycillin, which produced a rapid and complete recovery of kidney function. Infrared spectroscopy later confirmed the amoxycillin composition of the crystals. Since infrared spectroscopy is not easily available, we propose that these solubility tests of urinary crystals be used as a first-step investigation when amoxycillin crystalluria is suspected. [ABSTRACT FROM AUTHOR]

Background: Crystalluria is associated with some highly active anti-retroviral therapies (HAART's) used in the management of HIV/AIDS. Aims: This study used light microscopy to establish the prevalence of crystalluria among HIV/AIDS patients on HAART and identified the routine crystals present in their urine. Materials and Methods: In this simple randomised cross-sectional study, 200 HIV/AIDS participants, comprising 150 on HAART and 50 HAART-naïve were recruited from the HIV clinic at the Komfo Anokye Teaching Hospital (KATH). Urine and blood samples were collected, for urinalysis and the determination of the CD4 count, respectively. A well-structured pre-tested questionnaire was used to obtain socio-demographic data and clinical history of the participants. Results: The prevalence of crystalluria was higher among HIV-infected persons on HAART than those not on HAART (6.7% vs 4%; P = 0.733). Calcium oxalate and triple phosphate crystals were the crystal types present in their urine (3.5% and 2.5%, respectively) and was present only in HIV subjects on first line of treatment (without protease inhibitors). Participants aged between 40-50 years and those with hypersthenuria and acidic urine had the highest amount of crystalluria (41.6%, 83.3%, and 58.3%, respectively). Conclusion: HAART is associated with crystalluria in HIV patients. Light microscopy will be of disgnostic value in resource limited settings. [ABSTRACT FROM AUTHOR]

A 14-year-old girl was treated for 3 days with tosufloxacin (450 mg twice a day) for acute bronchitis and then developed acute kidney injury. Renal ultrasound showed enlarged kidneys without hydronephrosis. Urinalysis indicated drug crystal casts (2-3/ HPF), consistent with drug-induced crystalline nephropathy. The patient recovered gradually with i.v. hydration and discontinuation of tosufloxacin, leading to the diagnosis of tosufloxacin crystalline nephropathy. Medical practitioners should be aware that crystalline nephropathy can occur in pediatric patients receiving tosufloxacin. [ABSTRACT FROM AUTHOR]

With the introduction of potent combination antiretroviral therapy (cART) into clinical practice, HIV-infected patients have garnered much benefit. However, kidney disease continues to be a potential complication in this group. Whereas HIV-associated nephropathy (HIVAN) was the major renal complication prior to cART, co-morbid diseases and adverse renal effects of various drugs, in particular cART, now complicate the landscape. Clinicians now must differentiate HIVAN from cART nephrotoxicity. While sometimes this is easy and relatively straightforward, often the clinician faces a difficult challenge distinguishing these two etiologies of kidney disease. This review will discuss HIVAN and cART-related kidney disease and review the clinical and laboratory data that may be useful in differentiating these processes. Often, however, kidney biopsy may be required to differentiate HIVAN from cART nephrotoxicity as well as other kidney lesions associated with concurrent co-morbidities, both infectious and non-infectious. [ABSTRACT FROM AUTHOR]

Background and Objective: Hematuria is one of the common causes of pediatric nephrology and urology diseases and is reported in 0.5-2% of children. This study was performed to determine the causes of hematuria in infants and children. Methods: This descriptive study was done on 200 infants, children and adolescents in one month to 18 year old ages with chief complaint of hematuria in Hamadan, Iran. Patients were evaluated by urinalysis, urine culture, measurement of calcium, creatinine and uric acid in random urine sample and abdominal sonography. Results: Microscopic and gross hematuria was detected in 79.5% and 20.5% of patients, respectively. Hematuria was idiopathic in 74 (37%) of patients. Urinary tract stones (18%), urinary tract infections (15.5%), hypercalciuria (13%), hyperuricosuria (10%), urinary tract anomalies (5.5%) and glomerulonephritis (1%) were diagnosed as causes of hematuria. Conclusion: In 56% of patients, hematuria was caused by three common etiologies of stone, urinary tract infections and crystalluria. [ABSTRACT FROM AUTHOR]

The qualitative and quantitative analyses of crystalluria have clinical significance in the diagnosis and prognosis of urolithiasis. The aim of this paper is to provide a new accurate methodology to get qualitative and quantitative data on urine particulate in patients with renal stone disease. The procedure involves a urine collection, the separation of the solid residual by centrifugation, and its analysis by X-ray diffraction, utilizing a micro-diffractometer in order to analyze very low amounts of residual. The spectrum obtained was converted into 2 θ -I profiles and quantitatively refined by Rietveld method. The proposed methodology has the advantage to accurately quantify all crystalline phases and the amorphous component of the urine; anyway urine samples have to be centrifuged and analysed as soon as possible, because the quantitative results obtained by the X-ray microdiffraction showed that after some days and at room temperature urine increased significantly both amorphous and crystalline phases. [ABSTRACT FROM AUTHOR]

Background: Studies on the frequency of the different types of urinary crystals and the role of Fourier transform infrared microspectroscopy (FTIRM) for identification are few. We describe the results of a retrospective study on the prevalence and typology of crystalluria and on the role of FTIRM. Methods: Urinary crystals were identified using the combined knowledge of crystal morphology, birefringence features and urine pH (combined approach). When this was inconclusive, FTIRM was performed. Results: Crystalluria was found in 807 out of 9834 samples (8.2%). In 793, the combined approach identified 'typical' crystals, while in 14 FTIRM was needed to identify 'atypical' crystals. Among 'typical crystals', calcium oxalate (75.9%), uric acid (25.9%) and amorphous urates (7.9%), alone or in combination, were the most frequent. Brushite, ammonium biurate and cystine were the most rare (0.1%-0.7%). FTIRM identified 12 of 14 atypical crystals: three crystals were due to a drug (amoxicillin, indinavir, doubtful phenytoloxamine); four were due to calcium oxalate mono- or bihydrate, uric acid bihydrate or struvite; five were due to calcium carbonate, Tamm-Horsfall glycoprotein, or rare salt combinations. Conclusions: Crystalluria is not rare and most crystals can be identified by the combined approach. Occasionally, identification of crystals will require FTIRM. [ABSTRACT FROM AUTHOR]

Adenine phosphoribosyltransferase deficiency is a disorder in which 2,8-dihydroxyadenine (2,8-DHA) crystalluria is caused by a congenital deficiency in the enzyme adenine phosphoribosyltransferase (APRT). In most cases, APRT deficiency is caused by autosomal recessive inheritance of a homozygote of the mutant gene APRT*Q0 or APRT*J, but there are also some cases in which the disorder is caused by the compound heterozygote APRT*Q0 and APRT*J. In the patients described here, brown round crystals were found in their urinary sediment. Crystalluria was the first sign of APRT deficiency, thereafter confirmed by genetic screening for APRT*/Q0 and APRT*. We performed genetic screening for APRT*Q0 and APRT*J in two families and diagnosed three cases of APRT*Q0 /APRT*J compound heterozygote-type APRT deficiency. Genetic screening for APRT*Q0 and APRT*J of family members is effective for early diagnosis and early treatment for family members. [ABSTRACT FROM AUTHOR]

Defects in renal proximal tubule transport manifest in a number of human diseases. Although variable in clinical presentation, disorders such as Hartnup disease, Dent's disease, and Fanconi syndrome are characterized by wasting of solutes commonly recovered by the proximal tubule. One common feature of these disorders is aminoaciduria. There are distinct classes of amino acid transporters located in the apical and basal membranes of the proximal tubules that reabsorb >95% of filtered amino acids, yet few details are known about their regulation. We present our physiological characterization of a mouse line with targeted deletion of the gene collectrin that is highly expressed in the kidney. Collectrin-deficient mice display a reduced urinary concentrating capacity due to enhanced solute clearance resulting from profound aminoaciduria. The aminoaciduria is generalized, characterized by loss of nearly every amino acid, arid results in marked crystalluria. Furthermore, in the kidney, collectrin-deficient mice have decreased plasma membrane populations of amino acid transporter subtypes B0AT1, rBAT, and b0,+AT, as well as altered cellular distribution of EAACI. Our data suggest that collectrin is a novel mediator of renal amino acid transport and may provide further insight into the pathogenesis of a number of human disease correlates. [ABSTRACT FROM AUTHOR]

Calcium oxalate monohydrate (COM) crystals are the commonest component of kidney stones. Oxalate and COM crystals in renal cells are thought to contribute to pathology via prooxidant events. Using an in vivo rat model of crystalluria induced by hyperoxaluria plus hypercalciuria [ethylene glycol (EG) plus 1,25-dihydroxycholecalciferol (DHC)], we measured glutathione and energy homeostasis of kidney mitochondria. Hyperoxaluria or hypercalciuria without crystalluria was also investigated. After 1–3 wk of treatment, kidney cryosections were analyzed by light microscopy. In kidney subcellular fractions, glutathione and antioxidant enzymes were measured. In mitochondria, oxygen consumption and superoxide formation as well as cytochrome c content were measured. EG plus DHC treatment increased formation of renal birefringent crystal. Histology revealed increased renal tubular pathology characterized by obstruction, distension, and interstitial inflammation. Crystalluria at all time points led to oxidative stress manifest as decreased cytosolic and mitochondrial glutathione and increased activity of the antioxidant enzymes glutathione reductase and -peroxidase (mitochondria) and glucose-6-phosphate dehydrogenase (cytosol). These changes were followed by a significant decrease in mitochondrial cytochrome c content at 2–3 wk, suggesting the involvement of apoptosis in the renal pathology. Mitochondrial oxygen consumption was severely impaired in the crystalluria group without increased mitochondrial superoxide formation. Some of these changes were also evident in hyperoxaluria at week 1 but were absent at later times and in all calciuric groups. Our data indicate that impaired electron flow did not cause superoxide formation; however, mitochondrial dysfunction contributes to pathological events when tubular crystal-cell interactions are uncontrolled, as in kidney stones disease. [ABSTRACT FROM AUTHOR]

A 3-year-old child developed vomiting, ataxia, and crystalluria after ingestion of approximately 232 mg/kg of felbamate elixir. High-powered polarization microscopy of the urine revealed sharp, needle-like crystals. The analysis of the urine crystals showed unchanged felbamate (80.9%), monocarbamate felbamate (18.8%), and trace amounts of mercapturic acid conjugates of the metabolite 2-phenylpropenal (0.1%). The serum felbamate level 15 h after ingestion was 138 mg/L. Crystalluria and hematuria resolved with intravenous fluid therapy, and the child recovered within 24 h. [ABSTRACT FROM AUTHOR]

Morphoconstitutional analysis of urinary calculi, i.e. morphologic examination combined with Fourier transform infrared spectroscopy (FTIR), is of decisive interest for the diagnosis of rare but severe inherited or acquired stone diseases such as cystine, 2,8-dihydroxyadenine, xanthine, struvite, ammonium urate or drug-containing calculi as well as primary hyperoxalurias. In the absence of early diagnosis and proper management these diseases may lead to progressive loss of renal function. Among common forms of calcium oxalate (CaOx) stones, predominant CaOx monohydrate (whewellite) is mainly associated with hyperoxaluric conditions where- as predominant CaOx dihydrate (weddellite) is mainly associated with hypercalciuria, and this distinction is of interest to orient metabolic evaluation and preventive measures. Crystalluria examination, also based on morphology and FTIR, is a valuable diagnostic method when no stone is available for analysis. Presence of specific crystals (cystine, 2,8-dihydroxyadenine, struvite, ammonium urate) is diagnostic by itself. In all types of nephrolithiasis, serial crystalluria determination appears as a simple, cheap and reliable method to evaluate the risk of stone formation and assess the effectiveness of preventive measures. Determination of urinary crystal volume was in our experience a useful tool in the management of patients with cystinuria or primary hyperoxaluria in the post-transplantation period. In conclusion, both accurate morphologic and FTIR analysis of stones and serial crystalluria determination should be more largely used, in view of their value in the diagnosis and management of renal stone formers. [ABSTRACT FROM AUTHOR]

Summary: Purpose: To report a case of felbamate (FBM) urolithiasis. Methods: Urographic imaging [sonography, abdominal computed tomography (CT), intravenous pyelogram, voiding cystourethrogram] and urologic procedures (cystoscopy with lithotripsy, ureteral stent) to define and capture the stones. Stone identification was by infrared spectroscopy and gas chromatography/mass spectrometry. Results: A 15-year-old boy had painful hematuria, bilateral ureteral obstruction, and urinary retention. Kidney, bladder, and ureteral stones were found, and ureteral stent placement was required to relieve obstruction. The stone material was identified as FBM by chemical analysis. Stone formation ceased with discontinuation of FBM. Conclusions: FBM urolithiasis can occur, and possible contributory factors include high felbamate dosage, drug polypharmacy, and risk factors for forming stones of other types. FBM urolithiasis may be heralded by crystalluria. [ABSTRACT FROM AUTHOR]

Background: Fluoroquinolones are known to cause acute renal failure due to interstitial nephritis. Case Presentation: Here we present an elderly woman who developed oliguric acute kidney injury (AKI) after receiving oral and intravenous ciprofloxacin in a 48-hour period. Recently, several case reports have been published in the literature regarding the presence of crystals in the urine sediment of patients treated with ciprofloxacin for different types of systemic infections. Ciprofloxacin crystals precipitate in alkaline urine and provoke renal failure through intra-tubular precipitation. Conclusions: Conservative measures including intravenous hydration and avoidance of alkalinization of the urine can reverse this condition if applied in time. [ABSTRACT FROM AUTHOR]

A computer algorithm is described which allows urine to be modelled as a saturated equilibrium solution with respect to any combination of the solids calcium oxalate, calcium hydrogen phosphate (brushite), amorphous calcium phosphate, uric acid, sodium hydrogen urate and ammonium hydrogen urate. It is demonstrated that this model of urine, unlike the widely accepted metastable supersaturated solution model, explains the long-known calcium salt crystalluria versus pH curves of both non-stone-forming and stone-forming urine. Further, the saturation model accounts for why most “infection” stones do not contain calcium oxalate and why most “urate” stones are composed solely of uric acid and not admixed with alkali metal hydrogen urate salts. The supersaturation model of urine cannot explain satisfactorily these well-known phenomena. For example, the supersaturation model predicts that virtually all“infection” stones should contain calcium oxalate along with calcium phosphate and, perhaps, struvite. [ABSTRACT FROM AUTHOR]

1 Grepafloxacin is a new oral fluoroquinolone with potent activity against community acquired respiratory pathogens, including Streptococcus pneumoniae, and pharmacokinetic properties which allow once daily dosing. As part of its safety evaluation a study of 4 weeks duration was performed to compare the toxicity of grepafloxacin with that of a number of commercially available quinolones in the rat. 2 Groups of eight male Sprague-Dawley rats received either control material or grepafloxacin, enoxacin, lomefloxacin, ofloxacin or ciprofloxacin at an oral dosage of 300 mg/kg/day for 4 consecutive weeks. 3 Effects related to the antibacterial activity of the drugs were seen as increased caecal weight, decreased urinary excretion of sodium, increased water consumption, decreased urine volume, increased urine osmolality, soft stools and suppressed body weight gain. 4 It is well documented that fluoroquinolones can cause lesions in the cartilage of the major diarthrodial joints, and blister formation or erosion on the joint surface was observed in all quinolone-treated groups other than the grepafloxacin group. 5 Some quinolones, have been found to cause crystalluria, which is often associated with secondary nephropathy in laboratory animals due to the poor solubility of quinolones under the alkaline conditions of the urine. In the present study, needle-like crystals in the urinary sediment were observed in enoxacin and ciprofloxacin treated groups only. 6 In conclusion, grepafloxacin was well tolerated and showed a low potential for joint toxicity and crystalluria compared to other quinolones. [ABSTRACT FROM AUTHOR]

We report two cases of acute renal failure in patients with arteriosclerosis obliterans treated by intravenous infusion of naftidrofuryl oxalate. At renal biopsy the histological lesions were identical with those found in ARF due to hyperoxaluria of other causes, revealing tubular epithelial necrosis and massive intra-tubular precipitation of calcium oxalate monohydrate (Cl) crystals. A second study was then conducted in four other patients with arteriosclerosis obliterans to evaluate serum and urinary levels of oxalate, and crystalluria during the intravenous administration of 800 mg of naftidrofuryl oxalate per day for 10 days. During the course of treatment, the serum and urinary oxalate levels were found to increase substantially, with the gradual onset of massive Cl crystalluria. These results indicate that naftidrofuryl oxalate was responsible for the acute renal failure in the first two patients. High intravenous doses of naftidrofuryl oxalate must be used cautiously, with close surveillance of renal function. [ABSTRACT FROM PUBLISHER]

Forty adult male Wistar rats were placed in metabolic cages on a Ca-deficient diet (0.1%) for 7 days and then on a Ca-deficient, Na-oxalate (NaOx) enriched diet (20 mg/100 g) for another 14 days. The animaLs were subdivided into three groups receiving three different types of mineral water: group I (=13), Badoit (Ca 222 mg/i); group II (=14), Contrexéville (Ca 467mg/l); and group III (=13), Evian (Ca 78 mg/l). Another series of 25 rats (group I, n=9; group II, =8; group III, =8) underwent the same study protocol, except that they received a normal Ca diet (1%). On the low-Ca diet, urinary Ca-Ox monohydrate (COM) crystals were observed only under the Na-Ox diet, with a mean crystal number significantly greater in group III (16.7±4.5 crystals/mm ) than in group I or II rats (2.5 ± 1.5 or 4.1 ± 1.5 crystals/mm respectively). Urinary Ca concentrations decreased in all groups (/<0.001) under the Na-Ox diet, while urinary oxalate concentrations increased in all groups (<0.001). On the normal Ca diet, COM crystal excretion was observed only with the Na-Ox-enriched diet, but in this case feeding the Na-Ox diet did not modify urinary oxalate excretion. Ca/Ox ratio was significantly lower under 0.1% Ca diet than under normal Ca diet, related with the type and the number of crystals observed, demonstrating that assessment of crystalluria can provide an index of disease severity. Moreover, the hardness of the drinking water influ ences urinary COM crystal excretion only under a low-Ca, oxalate-rich diet, suggesting that the total calcium intake rather than the water calcium content is an important factor in the occurrence of Ca-Ox nephrolithiasis. [ABSTRACT FROM PUBLISHER]

Calcium oxalate monohydrate crystalluria was experimentally induced in male rats by administration of ethylene glycol. The crystalluria particles were separated by filtration and studied by scanning and transmission electron microscopy. They were associated with cellular degradation products. Organic material was present both on the surfaces of crystalluria particles as well as within them and was organized in radial striations and concentric laminations. It is proposed that crystal nuclei were formed by heterogeneous nucleation. These nuclei then adsorbed organic material and aggregated. The organic material polymerized resulting in the formation of a crystal-matrix unit which then grew and incorporated more organic material during the crystal growth. [ABSTRACT FROM AUTHOR]

Fresh samples of human urine adjusted to pH 6.8 were rapidly evaporated at 37°C to 1,250 mosmol/kg. The calcium phosphate precipitated was washed and the calcium measured by flame atomic absorption spectrophotometer. This procedure was found to be reasonably reproducible. When macromolecules were first removed by ultrafiltration the precipitated calcium was reduced by 76.9%. Addition of human Tamm-Horsfall mucoprotein (T-H) to the urine ultrafiltrates prior to evaporation largely but not completely restored the precipitated calcium. Clumping of crystals was studied quantitatively by passage through a nylon mesh. Mean retention on the mesh was strikingly reduced after ultrafiltration and increased by addition of T-H to the ultrafiltrates. These findings support the view that T-H triggers calcium phosphate crystal formation and clumping in whole urine. [ABSTRACT FROM AUTHOR]

The excretion of calcium oxalate and calcium phosphate crystals was studied in fractionated 24 h urine from 7 men with recurrent calcium oxalate stone disease, both before and during daily administration of 5 mg bendroflumethiazide. Urinary calcium, oxalate, magnesium, citrate, phosphate, pH, and inhibition of calcium oxalate crystal growth rate were analyzed in all samples. Exclusively calcium oxalate crystals were found in 30 per cent of the samples, all with a pH below 6.25, whereas calcium phosphate was the crystal type encountered in urine with a pH above 6.50. Bendroflumethiazide decreased the volume of calcium phosphate but not of calcium oxalate crystals. During the period of observation there was no correlation between calcium oxalate supersaturation and calcium oxalate crystal volume, but a relationship was demonstrated between calcium phosphate supersaturation and calcium phosphate crystal volume. [ABSTRACT FROM AUTHOR]

Crystalluria was induced in male Sprague-Dawley rats by implanting potassium-oxalate-containing miniosmotic 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 crystaluria. 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. [ABSTRACT FROM AUTHOR]

1) Low pyrophosphate urine was generated by passage through a nylon coil bearing immobilised inorganic pyrophosphatase. High pyrophosphate urine was made by addition of inorganic pyrophosphate. 2) Urine samples of low, normal, and high pyrophosphate content were rapidly evaporated at 37°C to 1,050 or 1,250 mosmol/L and the crystals formed studied by microscope, isotope and chemical methods. 3) Urinary pyrophosphate levels had no significant effect upon calcium oxalate crystals formed in whole urine at pH 5.3 or 6.1, or calcium phosphate crystals formed at pH 6.8. [ABSTRACT FROM AUTHOR]

It has been suggested recently that the first step in the formation of calcium oxalate stones appears to be crystallisation. This step is said to depend on the state of saturation of the urine. This hypothesis was checked in cystine stone formers. Cystine crystalluria was found in 83% of 24 urine samples from cystine stone formers (CSF) but in none of the 400 control samples and appears to be a good guide in the diagnosis of cystine lithiasis. Urinary cystine saturations was constantly higher in CSF than in non-cystine stone formers (NCSF) who exhibited undersaturated urine with respect to cystine. There was almost no overlap between these 2 groups. Crystals were never found in undersaturated urine and were always present when the saturation was above 1. There appears to be a good correlation between the level of urinary saturation and the presence of crystalluria and there is no need for any additional factor such as a defective inhibitor. The study underlines the limits of a therapeutic regimen of a high fluid intake and alkalinisation of the urine. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to compare vesical and renal calcium oxalate crystalluria in an attempt to correlate crystal formation with chemical composition and calcium oxalate saturation of renal urine. Material and Methods: Urine specimens were directly collected from the bladder and the kidney, of 11 stone formers and 11 control subjects under general anesthesia. The type of crystals present in urine as well as their size, number by cubic millimeter and state of aggregation were determined. In addition, calcium, magnesium, sodium, chloride, phosphate, citrate, oxalate, pyrophosphate and uric acid were measured in order to evaluate the calcium saturation status (EQUIL V program). Results: Calcium oxalate crystals were detected in 3 stone formers (27%) and 2 control subjects (18%) in vesical urine and in 4 stone formers (36%) and 3 control subjects (27%) in renal urine. Only 2 stone formers presented with simultaneous renal and vesical crystalluria. Subjects of the two groups with and without renal crystalluria were compared in terms of chemical composition and calcium oxalate saturation of renal urine. Crystalluric subjects (n = 7) had significantly higher uricosuria (p = 0.02), calciuria (p = 0.04), magnesiuria (p = 0.04) and calcium oxalate molar product (p = 0.05) than noncrystalluric (n = 15); calcium oxalate saturation was similar (p = 0.5). Conclusions: Beyond theorical considerations on lithogenesis, our observations and in particular the apparent discrepancy between renal and vesical crystalluria pose the problem of the clinical interest of the evaluation of calcium oxalate crystalluria based on freshly voided urine in the assessing the lithogenic risk or in the follow-up of patients who are particularly prone to stone recurrence. [ABSTRACT FROM AUTHOR]

Twenty male Wistar rats, weighing 150 g, were placed in metabolic cages on a 30% sucrose diet for 7 days, before allocation to two groups: a control group ( n = 5) and a lactose group ( n = 15). They received respectively a 30% sucrose diet or a 30% lactose diet for 8 weeks, each containing 0.67% calcium and 0.38% phosphorus. After 4 (T1) and 8 (T2) weeks, the serum calcium (Ca) and citrate levels were significantly ( P < 0.01) higher in rats fed the lactose diet. Serum alkaline phosphatase activity was increased in the lactose group ( P < 0.01) at T1 and T2. The lactose-rich diet induced an increase in urinary Ca excretion at T1 and T2; citrate excretion was only enhanced at T2 ( P < 0.001). No difference between the two groups was observed in urinary oxalate (Ox) excretion or creatinine clearance. Crystalluria analysis revealed a marked number (>300/mm3 at T1 and T2) of calcium oxalate dihydrate crystals (COD) in rats fed the lactose-rich diet, whereas no COD crystals were observed in sucrose-fed control rats at any time point. The formation of COD crystals in lactose-fed rats was related to an increase in calcium oxalate (CaOx) product (pCaOx), which was respectively 12.6 vs 3.9 at T1 and 10.5 vs 1.8 at T2, and an increase in CaOx ratio (Ca/Ox), which was 99.1 vs 7.5 and 67.5 vs 18.5 at T1 and T2, respectively. The high pCaOx and Ca/Ox ratios in the lactose group were due to hypercalciuria, in agreement with the number and the type of crystals. The present experimental model confirms that the ingestion of a 30% lactose diet increases urinary Ca excretion without changing urinary Ox excretion and shows for the first time that it induces a stable and marked crystalluria composed of COD. Such a non-nephrotoxic and stable model is of interest for the study of CaOx crystal formation secondary to hypercalciuria, and thus afterwards eventually for CaOx nephrolithiasis. [ABSTRACT FROM AUTHOR]

In male patients with idiopathic recurrent calcium urolithiasis (RCU) the effects of oral potassium sodium citrate (PSC) on acid-base, citrate and mineral metabolism were investigated. There were 17 normocitraturic and 15 hypocitraturic patients. The examination time points in our clinical laboratory were prior to medication and after 3, 6 and over 12 months of medication. Urine collection periods were over 24 h, 2 h - after an overnight fast - 3 h postprandially. Acceptance by the patients was poor, a large number refusing to take PSC for 12 months. Compliance of the patients continuing with the study was adequate as assessed by the urinary excretion of potassium and sodium. No unwanted side effects were observed. After 3 months of PSC medication a compensated metabolic alkalosis developed; in the urine calcium was decreased, while citrate, pH and oxalate were increased, as were hydroxyapatite supersaturation and calcium phosphate particles. After more than 12 months of PSC medication, citrate and pH tended toward the pretreatment baseline values, while hydroxyapatite supersaturation and calcium had already returned to pretreatment values. Despite ongoing PSC intake, patients with pre-existing hypocitraturia had lower urinary citrate than patients with previous normocitraturia, while the concomitant pH and hydroxyapatite supersaturation in the urine of the former remained at levels close to those of the latter. Under the influence of PSC, parathyroid gland function remained unchanged, but serum levels of bone alkaline phosphatase and osteocalcin were low, and urinary hydroxyproline was high. We conclude that (1) PSC shifts the acid-base status toward metabolic alkalosis, and also modulates bone metabolism; (2) over the long term, PSC may be unable to achieve a constantly high urinary citrate, in particular in RCU with pre-existent hypocitraturia - in contrast to its short- and medium-term effects. Long-term interrupted medication with PSC is proposed for the metaphylaxis of RCU. A regimen of this type may also be expected to yield more insight into the mechanism(s) underlying hypocitraturia. [ABSTRACT FROM AUTHOR]