Kidney stones, hypercalciuria, and recent insights into proximal tubule calcium reabsorption.

PURPOSE OF REVIEW: Most kidney stones are composed of calcium, and the greatest risk factor for kidney stone formation is hypercalciuria. Patients who form kidney stones often have reduced calcium reabsorption from the proximal tubule, and increasing this reabsorption is a goal of some dietary and pharmacological treatment strategies to prevent kidney stone recurrence. However, until recently, little was known about the molecular mechanism that mediates calcium reabsorption from the proximal tubule. This review summarizes newly uncovered key insights and discusses how they may inform the treatment of kidney stone formers. RECENT FINDINGS: Studies examining claudin-2 and claudin-12 single and double knockout mice, combined with cell culture models, support complementary independent roles for these tight junction proteins in contributing paracellular calcium permeability to the proximal tubule. Moreover, a family with a coding variation in claudin-2 causing hypercalciuria and kidney stones have been reported, and reanalysis of Genome Wide Association Study (GWAS) data demonstrates an association between noncoding variations in CLDN2 and kidney stone formation. SUMMARY: The current work begins to delineate the molecular mechanisms whereby calcium is reabsorbed from the proximal tubule and suggests a role for altered claudin-2 mediated calcium reabsorption in the pathogenesis of hypercalciuria and kidney stone formation.

Tea and coffee consumption and pathophysiology related to kidney stone formation: a systematic review.

OBJECTIVE: To explore the mechanisms behind the potential protective effect of coffee and tea consumption, regarding urinary stone formation, previously demonstrated in large epidemiological studies. METHODS: A systematic review was performed using the Medline, Cochrane library (CENTRAL) and Scopus databases, in concordance with the PRISMA statement. English, French and Spanish language studies, regarding the consumption of caffeinated and decaffeinated coffee and tea, and the relationship to urinary stone formation were reviewed. Meta-analyses, systematic reviews, case reports and letters, unpublished studies, posters and comments abstracts were excluded. RESULTS: As per the inclusion criteria, 13 studies were included in the final review. The major findings show that caffeine increases urinary excretion of calcium, sodium and magnesium, in addition to a diuretic action with consumption > 300-360 mg (approximately four cups of coffee). Together with other components of coffee, this beverage might have potential protective effects against the formation of urinary stones. Tea exerts many protective effects against stone formation, through the accompanying water intake, the action of caffeine and the effects of components with antioxidant properties. CONCLUSION: Caffeine has a hypercalciuric effect, balanced partially by a diuretic effect which appears after consumption of large quantities of caffeine. The current available literature supports in general, a potentially protective role for tea against stone formation, mainly for green tea. Additional standardization in this field of research, through specification of tea and coffee types studied, and their respective compositions, is needed for further clarification of the relation between coffee, tea and urinary stones.

Amelioration of hyperoxaluria-induced kidney dysfunction by chemical chaperone 4-phenylbutyric acid.

Hyperoxaluria is characterized by an increased excretion of urinary oxalate which is caused by inherited disorders or high oxalate intake leading to renal stone ailment. Until date, reactive oxygen species and inflammation has been convicted for the progression of kidney stones for which antioxidant therapy has been employed. However, recent studies have linked the association of endoplasmic reticulum stress and oxidative imbalance in the progression of renal diseases. Considering oxidative stress being at forefront in causing hyperoxaluric consequences, current study was designed to correlate the impact of hyperoxaluria and regulation of oxidative imbalance via inhibition of endoplasmic reticulum stress by 4-phenylbutyric acid (4-PBA). Male wistar rats were subdivided into three groups, i.e., normal control (C), hyperoxaluric rats given ethylene glycol (EG), and hyperoxaluric rats treated with 4-PBA (EG + PBA). After 28 days of treatment, assessment of antioxidant defence system, inflammation, ER stress, and subsequent unfolded protein response was studied in renal tissue. It was found that the hyperoxaluric insult led to a marked damage to the renal tissue resulting in compromised antioxidant levels, upregulation of ER stress markers along with a steep surge in the extent of inflammation. However, 4-PBA treatment significantly curtailed the deleterious effects of hyperoxaluria by lowering down the level of stress markers as well as normalizing the antioxidant defence enzymes. Therefore, chemical chaperones can be deemed as a new class of drugs for the treatment of hyperoxaluric induced renal damage.

Drug-Induced Kidney Stones and Crystalline Nephropathy: Pathophysiology, Prevention and Treatment.

Drug-induced calculi represent 1-2% of all renal calculi. The drugs reported to produce calculi may be divided into two groups. The first one includes poorly soluble drugs with high urine excretion that favour crystallisation in the urine. Among them, drugs used for the treatment of patients with human immunodeficiency, namely atazanavir and other protease inhibitors, and sulphadiazine used for the treatment of cerebral toxoplasmosis, are the most frequent causes. Besides these drugs, about 20 other molecules may induce nephrolithiasis, such as ceftriaxone or ephedrine-containing preparations in subjects receiving high doses or long-term treatment. Calculi analysis by physical methods including infrared spectroscopy or X-ray diffraction is needed to demonstrate the presence of the drug or its metabolites within the calculi. Some drugs may also provoke heavy intra-tubular crystal precipitation causing acute renal failure. Here, the identification of crystalluria or crystals within the kidney tissue in the case of renal biopsy is of major diagnostic value. The second group includes drugs that provoke the formation of urinary calculi as a consequence of their metabolic effects on urinary pH and/or the excretion of calcium, phosphate, oxalate, citrate, uric acid or other purines. Among such metabolically induced calculi are those formed in patients taking uncontrolled calcium/vitamin D supplements, or being treated with carbonic anhydrase inhibitors such as acetazolamide or topiramate. Here, diagnosis relies on a careful clinical inquiry to differentiate between common calculi and metabolically induced calculi, of which the incidence is probably underestimated. Specific patient-dependent risk factors also exist in relation to urine pH, volume of diuresis and other factors, thus providing a basis for preventive or curative measures against stone formation.

Presentation of a method at the Exploration Stage according to IDEAL: Percutaneous nephrolithotomy (PCNL) under local infiltrative anesthesia is a feasible and effective method - retrospective analysis of 439 patients.

INTRODUCTION: This study addresses minimally invasive anesthesiologic and analgetic approaches for stone surgery in the upper urinary tract. Aim of this retrospective analysis is to compare feasibility, safety and complication rates of percutaneous nephrolithotomy (PCNL) under local infiltration anesthesia alone (Group I) and additive intravenous analgetics and/or sedative medications (Group II). MATERIAL AND METHODS: This is a single center study. A total of 439 patients have been included from November 2003 until March 2012. A total of 226 patients were assigned to Group I receiving local infiltration anesthesia alone, whereas 213 patients were assigned to Group II receiving additive intravenous analgetics and/or sedative medications. Demographic characteristics and stone characteristics have been evaluated to determine feasibility, complication rates for safety, and stone-free rates for effectiveness. The study and the reported technique have then been retrospectively analysed according to the IDEAL stages of surgical innovation. RESULTS: All included patients who accepted local infiltration anesthesia underwent PCNL successfully. The mean American Society of Anesthesiologists score (ASA) of the included patients was 2.15 ±0.37 (range, 1-4). PCNL was indicated in 138 patients due to pelvic calculi, in 171 patients due to renal calculi, in 66 patients due to partial staghorn, in 48 patients due to complete staghorn and in 16 patients due to upper ureteral stones. The total stone free rate in our patients was 78.4% over all stone localizations. Compared to the possibility of using additive intravenous analgetics and/or sedative medications we could show differences in the median age (p=0.005) suggesting that older patients did better tolerate the infiltration anesthesia than patients at younger ages. We did also remark not statistically significant differences in Group I and Group II as for number of tracts, operation duration, hemoglobin drop, fever, transfusion rate, and stone free rate, but not for severe complications such as perirenal hematoma, colon perforation, pleura perforation, AV fistula, skin fistula, and mortality rate. CONCLUSION: PCNL performed under local infiltration anesthesia is a feasible method. It provides satisfactory positive clinical outcomes. Younger age seems to predispose to conversion to extended anesthesiologic procedures. When retrospectively applying the IDEAL criteria, the method can be assigned to the E level or stage 2b.

Predicting Patients with Inadequate 24- or 48-Hour Urine Collections at Time of Metabolic Stone Evaluation.

PURPOSE: We aimed to understand the characteristics of patients who are less likely to submit adequate urine collections at metabolic stone evaluation. METHODS: Inadequate urine collection was defined using two definitions: (1) Reference ranges for 24-hour creatinine/kilogram (Cr/24) and (2) discrepancy in total 24-hour urine Cr between 24-hour urine collections. There were 1502 patients with ≥1 kidney stone between 1998 and 2014 who performed a 24- or 48-hour urine collection at Northwestern Memorial Hospital and who were identified retrospectively. Multivariate analysis was performed to analyze predictor variables for adequate urine collection. RESULTS: A total of 2852 urine collections were analyzed. Mean age for males was 54.4 years (range 17-86), and for females was 50.2 years (range 8-90). One patient in the study was younger than 17 years old. (1) Analysis based on the Cr 24/kg definition: There were 50.7% of patients who supplied an inadequate sample. Females were nearly 50% less likely to supply an adequate sample compared with men, P<0.001. Diabetes (odds ratio [OR] 1.42 [1.04-1.94], P=0.026) and vitamin D supplementation (OR 0.64 [0.43-0.95], P=0.028) predicted receiving an adequate/inadequate sample, respectively. (2) Analysis based on differences between total urinary Cr: The model was stratified based on percentage differences between samples up to 50%. At 10%, 20%, 30%, 40%, and 50% differences, inadequate collections were achieved in 82.8%, 66.9%, 51.7%, 38.5%, and 26.4% of patients, respectively. Statistical significance was observed based on differences of ≥40%, and this was defined as the threshold for an inadequate sample. Female sex (OR 0.73 [0.54-0.98], P=0.037) predicted supplying inadequate samples. Adequate collections were more likely to be received on a Sunday (OR 1.6 [1.03-2.58], P=0.038) and by sedentary workers (OR 2.3 [1.12-4.72], P=0.023). CONCLUSION: Urine collections from patients during metabolic evaluation for nephrolithiasis may be considered inadequate based on two commonly used clinical definitions. This may have therapeutic or economic ramifications and the propensity for females to supply inadequate samples should be investigated further.

[Rehabilitation of the patients suffering from chronic calculous pyelonephritis].

The objective of the present study was to develop a new technology for the balneotherapeutic treatment of the patients with urolithiasis by means of combined application of mineral water, mineral baths (1 therapeutic complex), sinusoidal modulated current (SMC-phoresis of nicotinamide), and preparations inhibiting urine concrement formation. The overall efficacy of this combined balneo-, physio-, radio-, and pharmacotherapy of the patients presenting with secondary calculous pyelonephritis amounted to 94% compared with 73.4% using balneotherapy alone (p1-2 < 0.05). Summation of positive effects of balneo-, physio-, radio-, and pharmacotherapies promoted normalization of the functional state of the kidneys and the upper urinary tracts which in its turn contributed to the improvement of the patient's quality of life.

The role of functional urodynamic disorders in the pathogenesis of urolithiasis.

OBJECTIVE: The aim of this study was to analyze the functional urodynamic parameters, which affect renal function and can promote stone formation. MATERIALS AND METHODS: We examined sixty consecutive patients with renal and ureteral stones and indication to urinary diversion by nephrostomy tube or indwelling catheter In upper urinary tract, urodynamics was assessed with the help of electromanometry and multichannel impedance ureterography. To measure ureteral peristalsis, a probe equipped with 9 successively incorporated electrodes was indwelled retrogradely into distal ureter through a urethroscope. The documented data included renal pelvic pressure (RPP) and the number of ureteric contractility parameters such as peristalsis amplitude, peristalsis rate, the ureteral wall tone, the characteristics of contractile waveform and its direction (antegrade or retrograde). Urinary biochemistry and enzymuria were studied in order to characterize the lithogenic activity and renalfunction. The patients were divided into three groups: group 1 included patients with acute pyelonephritis caused by unilateral stone obstruction (n = 24), group 2 patients with stones and non-acute latent chronic pyelonephritis (n = 31) and group 3 unobstructed patients without signs of inflammation (n = 5). RESULTS: In the three groups of patients, the mean baseline RPP values were, respectively 28.7 +/- 2.6 (range 20.0-32.4); 15.6 +/- 1.9 (range 3.5-29.0); and 3.6 +/- 1.4 (range 0-8) cm H2O. The ratio of GGT to urinary creatinine changed similarly: it was elevated during acute inflammation, moderately enhanced during the chronic process, but significantly decreased after stone removal and resolution of inflammation (11.5 +/- 3.2; 8.1 +/- 2.0, and 1.6 +/- 0.5 unit/L). Biochemical evaluation revealed 54% patients with enhanced lithogenic activity assessed by elevated calcium and oxalates in the urine (4.95 +/- 0.25 mM and 504 +/- 35 microM, correspondingly) and low level of citrates (2.5 +/- 0.1 mM). In a subgroup of 11 patients with urolithiasis the baseline RPP values were assessed in relation to ureteral contractile activity in the distal region of ureter. Low RPP was found in a patient (9%) with strong ureteral contractions and a low tone while RPP was moderately higher in another patient (9%) with moderate mean peristaltic amplitude value but with elevated tone of ureteral wall. In the majority of examined patients with significantly elevated mean RPP value (45%), peristalsis of distal ureter was characterized by weak long-term and frequent contractions as well as increased tone with respect to the patients with normal RPP. The patients (36%) with moderately increased RPP demonstrated strong frequent contractions in the distal ureter and low ureteral wall tone. Changes in urodynamic parameters in patients examined before and immediately after ureteroscopy and lithotripsy procedures were observed. Factors affecting the ureteral wall tone were duration of stone disease, location and disposition of stones. CONCLUSIONS: Our clinical observations obtained with the help of physiological methods revealed various factors modulating the urodynamic disorders in renal pelvis: temporary or persistent elevation of pelvic pressure; peculiarities of contractile function in distal ureter manifested by the tonic changes and variations in contractile amplitude, and certain abnormalities in propagation of contractile wave in the upper urinary tract. The reported urodynamic changes in patients with stone disease can be supplementary pathogenic factors causing deterioration of renal function probably followed by stone formation.

The protective effects of the traditional Chinese herbs against renal damage induced by extracorporeal shock wave lithotripsy: a clinical study.

Extracorporeal shock wave lithotripsy (ESWL)-induced renal damage can occur as a result of multiple mechanisms. We have reported previously that Astragalus membranaceus, Salvia miltiorrhiza, a decoction of six drugs containing rhizoma Rehmanniae preparata and supplements of a few traditional Chinese medicinal herbs for invigorating the kidney and excreting calculus, have a protective effect on renal injury induced by high-energy shock waves (HESW) in rabbits. In this clinical study we further investigate the protective effects of these traditional Chinese herbs against renal damage induced by ESWL. Sixty consenting patients with renal calculus who underwent ESWL treatment were included and randomly assigned to the medication group or control group. Post-ESWL plasma nitric oxide (NO), endothelin-1 (ET-1), malondialdehyde (MDA), and serum tumor necrosis factor α (TNF-α) increased significantly in the controls (P < 0.05), while in the medication group, slightly but not significantly elevated levels of plasma ET-1, NO, and serum TNF-α were found. The difference between the groups was statistically significant (P < 0.05). The levels of superoxide dismutase (SOD) decreased gradually in the controls, reaching a trough 72 h after ESWL (P < 0.05), while in the treated group it was unchanged, and remained at a level higher versus the controls (P < 0.05). Plasma NO peaked twice by 72 h and at 1 week in the controls (P < 0.05). Urinary enzymes and ß(2)-microglobulin increased significantly and peaked by 24 h and immediately after ESWL (P < 0.05). These values were greater in the controls, and the difference was statistically significant (P < 0.05). This study demonstrates that the preparations of traditional Chinese medicines for invigorating the kidney and excreting calculus can reduce renal tubular damage induced by ESWL, and can shorten the recovery time of renal tubules in human subjects.

Effects of pomegranate juice on hyperoxaluria-induced oxidative stress in the rat kidneys.

To evaluate the role of the inducible nitric oxide synthase (iNOS), selective nuclear factor-kB (NF-kB), and p38-mitogene-activated protein kinase (p38-MAPK) on hyperoxaluria-induced oxidative stress and stone formation in rat kidneys. The rats were divided into five groups: group 1, control group; group 2: ethylene glycol (EG) group; group 3: EG + pomegranate juice (PJ)-low group; group 4: EG + PJ-middle group; group 5: EG + PJ-high group. Rats were sacrificed on 7, 15, and 45 days. The iNOS expression, p65-NF-kB and p38-MAPK activity, and oxidative stress markers were evaluated in the kidney. Crystal depositions were evident on day 7, and mild and severe crystallization were observed on day 15 and 45 in EG group, respectively. There was limited or no crystal formation in rats in both middle- and high-dose PJ groups when compared to low-dose PJ group. Crystal depositions, iNOS, p38-MAPK and p65-NF-kB activity, and oxidative stress markers were found to be decreased by middle- and high-dose PJ treatment. PJ was found to have inhibitory effects on renal tubular cell injury and oxidative stress caused by oxalate crystals by reducing ROS, iNOS, p38-MAPK, and NF-kB expression.

Calcium supplementation and incident kidney stone risk: a systematic review.

BACKGROUND: A report of a small increase in kidney stone risk in the calcium treatment arm of the Women's Health Initiative (WHI) led to a reduction in U.S. calcium supplement sales. OBJECTIVE: To reassess kidney stone risk in postmenopausal women using data accumulated in calcium supplement trials, bone active agent registration trials, and in unpublished WHI data available online; and to compare these estimates with formal published epidemiological studies of stone risk. METHODS: Literature review of published studies relating calcium intake to stone risk; adverse event report data from pharmaceutical industrial trials designed to evaluate bone active agents. RESULTS: Stone risk in postmenopausal women has increased substantially in the past 40 years, but absolute population incidence estimates vary widely from a low of about 70 incidents/100,000/yr for Olmsted County, MN, today, to a concurrent high of approximately 190/100,000/yr for the Nurses' Health Study II. Reported WHI incidence rates are higher still, with values around 300/100,000/yr for various WHI subgroupings. The reasons for these discordances are unclear. Despite this uncertainty about background rate, most of the studies show no increase in stone risk with high calcium intake (from either diet or supplements). Contrariwise there is a substantial body of evidence, both from controlled trials and from observational studies, indicating that there is an inverse relationship between calcium intake and stone risk.

Determinants of 24-hour urinary oxalate excretion.

BACKGROUND AND OBJECTIVES: Higher levels of urinary oxalate substantially increase the risk of calcium oxalate kidney stones. However, the determinants of urinary oxalate excretion are unclear. The objective was to examine the impact of dietary factors, age, body size, diabetes, and urinary factors on 24-h urinary oxalate. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We conducted a cross-sectional study of 3348 stone forming and non-stone-forming participants in the Health Professionals Follow-up Study (men), the Nurses' Health Study (older women), and the Nurses' Health Study II (younger women). RESULTS: Median urinary oxalate was 39 mg/d in men, 27 mg/d in older women, and 26 mg/d in younger women. Participants in the highest quartile of dietary oxalate excreted 1.7 mg/d more urinary oxalate than participants in the lowest quartile (P trend 0.001). The relation between dietary and urinary oxalate was similar in individuals with and without nephrolithiasis. Participants consuming 1000 mg/d or more of vitamin C excreted 6.8 mg/d more urinary oxalate than participants consuming <90 mg/d (P trend < 0.001). Body mass index, total fructose intake, and 24-h urinary potassium, magnesium, and phosphorus levels also were positively associated with urinary oxalate. Calcium intake and age were inversely associated with urinary oxalate. After adjustment for body size, participants with diabetes excreted 2.0 mg/d more urinary oxalate than those without diabetes (P < 0.01). CONCLUSIONS: The impact of dietary oxalate on urinary oxalate appears to be small. Further investigation of factors influencing urinary oxalate may lead to new approaches to prevent calcium kidney stones.

Biochemical characterization of primary hyperparathyroidism with and without kidney stones.

The exact metabolic-physiological background for kidney stone formation in primary hyperparathyroidism (PHPT) is unclear. To obtain clarification, this retrospective data analysis was conducted in 131 patients with PHPT who had undergone a detailed ambulatory evaluation on a random diet since 1980. The baseline biochemical presentation of 78 patients with PHPT with stones was compared with that of 53 patients without stones. Compared to those without stones, the stone-forming patients had a more marked hypercalciuria (343 +/- 148 vs. 273 +/- 148 mg/day, P < 0.01). Urinary saturation of calcium oxalate and brushite was significantly higher in stone-formers. Serum PTH and fasting urinary calcium were similar between the two groups, but serum phosphorus was significantly lower in stone-formers. Serum calcitriol (available in some patients) showed a slightly higher mean value in stone-formers but the difference was not significant. The increment in urinary calcium after oral load of 1-g calcium was twofold higher among stone-formers. Radial shaft and L2-L4 bone mineral densities resided within the normal ranges. Stone-formers with PHPT display exaggerated urinary calcium excretion due to intestinal hyperabsorption of calcium, contributing to a greater enhancement of the saturation of stone-forming calcium salts.

Inhibition of calcium oxalate nephrotoxicity with Cymbopogon schoenanthus (Al-Ethkher).

We investigated the effects of Cymbopogon schoenanthus herb on experimental induced kidney stones in male Wistar albino rats. Oxalate nephrotoxicity was experimentally induced by 200 mg single dose of glycolic acid given orally (gavage). Rats were divided into three groups, glycolic acid, glycolic acid plus Cymbopogon schoenanthus, and control (D. water). Urine analysis of blood urea nitrogen (BUN), creatinine, and calcium revealed significant differences comparing to the control. In addition, significant pathological changes were found in the kidney revealed by histopathological studies. Daily oral treatment with Cymbopogon schoenanthus (1 ml of the extract) significantly corrected the incidence of nephrotoxicity, BUN, creatinine, and calcium level differences. Moreover, optimization studies showed highly potent diuretic activity of Cymbopogon schoenanthus. After three days of experiments, four rats treated with the glycolic acid only died. The rest of animal survived and looked healthy.

Causes of hypocitraturia in recurrent calcium stone formers: focusing on urinary potassium excretion.

BACKGROUND: Multiple factors associated with hypocitraturia have been identified. However, limited studies addressing the causal relationship to hypocitraturia are available. We therefore conducted this study to determine factors associated with hypocitraturia and show their causal relationship in recurrent calcium stone formers. METHODS: Dietary review and 24-hour urine samples were obtained from all recurrent calcium stone formers referred for metabolic workup in the stone clinic. One month of oral potassium chloride supplementation was prescribed to stone formers to determine the causal relationship between urinary potassium and citrate levels. RESULTS: Eighty-three subjects, 44 men and 39 women, were recruited to participate in this study. Hypocitraturia (citrate < 300 mg/d [<1.43 mmol/d]) was found in 50.6% of subjects. Four independent urinary variables associated with hypocitraturia were identified, including potassium level, net gastrointestinal alkaline absorption, calcium level, and titratable acid. Urinary potassium level was the strongest predictor of urinary citrate level. Hypocitraturic subjects also had lower fruit intake compared with subjects with high urinary citrate levels. Potassium chloride supplementation to a subgroup of this population (n = 58) resulted in a significant increase in urinary citrate excretion (350.73 +/- 27.25 versus 304.15 +/- 30.00 mg/d [1.67 +/- 0.13 versus 1.45 +/- 0.14 mmol/d]; P < 0.02), but no alteration in fractional excretion of citrate (19.7% +/- 2.7% versus 23.1% +/- 2.4%; P > 0.05). CONCLUSION: Hypocitraturia was found to be a common risk factor associated with recurrent calcium stone formation and low urinary potassium level, low alkaline absorption, low urinary calcium level, and high titratable acid excretion. Hypocitraturia is predominantly of dietary origin. Estimation of fruit intake should be included in the metabolic evaluation for recurrent calcium stone formation.

Modificación de los cólicos nefríticos y de la excreción de calcio en orina de 24 horas en el hiperparatiroidismo primario tras la paratiroidectomía / Modification of nephritic colic and 24-hour calcium excretion in urine in primary hyperthyroidism after parathyroidectomy

Se documentó la frecuencia de cólicos nefríticos en pacientes con hiperparatiroidismo primario, y se determinó su modificación tras la paratiroidectomía; así mismo se estudiaron parámetros de laboratorio tales como calcio, fósforo y parathormona en suero, y excreción de calcio en orina de 24h previos y posteriores a la intervención. A la vista de los resultados se puede concluir que la paratiroidectomía es útil en el tratamiento de la enfermedad calculosa renal producida por el hiperparatiroidismo primario (AU)

We documented the frequency of nephritic colic in patients with primary hiperparathyroidism, and determined its modification after the parathyroidectomy; we also studied laboratory parameters such as calcium, phosphorus and parathyroid hormone in serum, and the excretion of Cao 24h, previous and later to the intervention. At sight of the results it is possible to be concluded that the parathyroidectomy is useful in the treatment of the kidney stone disease produced by the primary hyperparathyroidism (AU)

Preventive effects of green tea on renal stone formation and the role of oxidative stress in nephrolithiasis.

PURPOSE: Urinary stones are similar to arteriosclerosis in epidemiology, mechanism, calcification composition and age at frequent occurrence. The calcification that occurs in arteriosclerosis is inhibited by antioxidants. Green tea leaves contain approximately 13% catechins, which have been shown to have antioxidant effects. We investigated the inhibitory, antioxidative effects of green tea on calcium urinary stone formation. MATERIALS AND METHODS: A total of 120 Wistar rats were divided into 4 groups, namely group 1-control rats receiving saline, group 2-stone group rats administered ethylene glycol (EG) and vitamin D3, group 3-drink group rats administered EG, vitamin D3 and green tea given as drinking water, and group 4-powder group rats administered EG, vitamin D3 and 2.5% powdered green tea leaves mixed in a powder diet. Pooled 24-hour urine samples and blood samples were collected and the 2 kidneys were excised 7, 14 and 21 days after administration, respectively. One kidney was used for immunohistological examination of osteopontin, superoxide dismutase (SOD), p65, p53 and bcl-2 expression, in situ hybridization of osteopontin and detection of apoptosis, while the other was used for quantitative analysis of SOD activity. RESULTS: Green tea treatment decreased urinary oxalate excretion and calcium oxalate deposit formation. Green tea treatment increased SOD activity compared with the stone group. The degree of apoptosis in the stone group was significantly increased compared with the drink and powder groups. CONCLUSIONS: The inhibitory effect of green tea on calcium oxalate urolithiasis is most likely due to antioxidative effects.

Effects of intraperitoneally administered vitamin E and selenium on calcium oxalate renal stone formation: experimental study in rat.

Forty-eight Wistar rats were treated for 3 weeks with water containing 0.7% ethylene-glycol and divided into four groups. The first group, used as control, has received sodium chloride at 1 ml/100 g BW daily. The second group was intraperitoneally injected with selenium at 10 micrograms/d per 100 g BW as NaSeO3 for 3 weeks. The third group was intraperitoneally administered with 15 mg Vit E/d per 100 g BW as alpha-tocopherol acetate for 3 weeks. The last group was simultaneously administered vitamin E and Se at the same doses and periods as the precedent groups. One day before the end of the treatment, each animal was placed in a metabolic cage for collection of 24 h urine samples and determination of urinary creatinin, urea, calcium, magnesium, phosphate and oxalate levels. Immediately thereafter, all the rats were anesthetized and aortic blood was collected to determine the same parameters as in urine. The kidneys were also removed to determine calcium oxalate deposits, dry weight and to conduct a histological examination. Our results showed decreased ionic product and increased magnesium fractional reabsorption in the group receiving only selenium and in the group receiving selenium in combination with vitamin E, in comparison with the control animals. In view of the knowledge concerning the same protective action of Vit E and selenium, regardless of tubular membrane alteration, the absence of any inhibitory effect of Vit E on calcium oxalate formation suggests that selenium, like other minerals, could be stuck onto the crystal surface and would inhibit induction of new crystals, growth and aggregation.

Pain management in polycystic kidney disease.

Pain is a common complaint in patients with autosomal-dominant polycystic kidney disease, and a systematic approach is needed to differentiate the etiology of the pain and define an approach to management. A thorough history is the best clue to the multifactorial causes of the pain, superimposed upon an understanding of the complex innervation network that supplies the kidneys. The appropriate use of diagnostic radiology (especially MRI) will assist in differentiating the mechanical low back pain caused by cyst enlargement, cyst rupture and cyst infection. Also, the increased incidence of uric acid nephrolithiasis as a factor in producing renal colic must be considered when evaluating acute pain in the population at risk. MRI is not a good technique to detect renal calculi, a frequent cause of pain in polycystic kidney disease. If stone disease is a possibility, then abdominal CT scan and/or ultrasound should be the method of radiologic investigation. Pain management is generally not approached in a systematic way in clinical practice because most physicians lack training in the principles of pain management. The first impulse to give narcotics for pain relief must be avoided. Since chronic pain cannot be "cured," an approach must include techniques that allow the patient to adapt to chronic pain so as to limit interference with their life style. A detailed stepwise approach for acute and chronic pain strategies for the patient with autosomal dominant polycystic kidney disease is outlined.