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PubMedDate not supplied

Effects of selected therapeutic agents on urolithiasis induced by terephthalic acid in the male weanling Fischer 344 rat.

Exposure of male weanling Fischer 344 rats to 4.0% terephthalic acid (TPA) in the diet (positive controls) for two weeks (postnatal days 28-42) resulted in a 50% incidence of bladder calculi, aciduria, elevated urinary excretion of calcium (Ca) and magnesium (Mg), and slightly elevated serum levels of Ca and Mg relative to negative controls. Possible mechanisms of TPA-induced urolithiasis were examined by daily oral administration of allopurinol, chlorothiazide, or neutral phosphates, at their recommended therapeutic doses during exposure to dietary 4.0% TPA. An additional group was fed 4.0% TPA and 4.0% sodium bicarbonate in the diet for two weeks. Chlorothiazide or dietary bicarbonate abolished TPA-induced urolithiasis, but allopurinol and neutral phosphates had no effect. Bicarbonate increased water intake above that of positive controls and ameliorated the TPA-induced aciduria. It also increased urinary Mg and TPA above positive control values. Chlorothiazide reduced urinary Ca and TPA levels below those of positive controls. Treatment with chlorothiazide, neutral phosphates or bicarbonate slightly reduced serum Ca below the levels in either positive or negative controls. Drug treatment did not alter TPA-induced elevated serum Mg levels, but bicarbonate reduced serum Mg levels to negative control values. In conclusion, TPA-induced urolithiasis in male weanling rats was abolished by therapeutic agents which reduced urinary Ca and TPA excretion (chlorothiazide), or which enhanced water intake, urinary Mg and TPA excretion, and ameliorated TPA-induced aciduria (dietary bicarbonate). These factors appear to be critical for TPA-induced urolithiasis.

Allopurinol↗

PubMed1996

Dietary and behavioral risk factors for urolithiasis: potential implications for prevention.

Few studies have examined urolithiasis in primary care populations, and limited data are available on non-drug interventions to reduce the risk for urinary calculi. Therefore, we conducted a case control study of patients enrolled in a large prepaid health maintenance organization. The 240 study cases were men experiencing initial episodes of urolithiasis, ascertained by reviewing radiology procedure logs and medical records. The 392 controls were age-matched men with no history of urolithiasis chosen from a list of randomly selected men. Data were collected using standardized telephone interviews. Odds ratios were calculated for potential risk factors. In logistic regression analyses the risk for urinary tract calculi was related to both consumption variables, such as a low-fat or weight reduction diet (adjusted odds ratio, 0.41; P < 0.0005) and beer drinking (adjusted odds ratio, 0.41; P < 0.0001), and to demographic variables, such as African-American ethnicity (adjusted odds ratio, 0.29; P = 0.03) and a positive family history (adjusted odds ratio, 2.22; P < 0.001). These findings suggest the need to evaluate appropriate behavioral interventions to reduce the morbidity associated with urolithiasis. Prospective studies should evaluate the possibilities that beer drinking, even in modest amounts, and a low-fat or weight reduction diet are associated with substantial reductions in risk.

Adult↗

PubMed2003

Study on the prevalence and incidence of urolithiasis in Germany comparing the years 1979 vs. 2000.

OBJECTIVES: In 1979, we conducted a representative study to determine the prevalence and incidence of urolithiasis in Germany. Significant progress in stone therapy and changes in nutritional and environmental factors since then consequently led to a second study in 2001 under the same conditions as in 1979. METHODS: A representative sample of 7500 persons from all over Germany was questioned on the occurrence of urinary stones during their lifetimes (prevalence) and on acute urolithiasis in 2000 (incidence). Additionally, data were collected on urinary stone therapy and metaphylaxis. The current data were then compared with those from 1979. RESULTS: Prevalence has risen from 4% to 4.7% from 1979 to 2001. 9.7% of the 50-64 year old males in 2000 had already had urinary stones (females: 5.9%). The current recurrence rate of urinary stones was estimated to be 42%. In the year 2000, the incidence of urolithiasis in Germany was found to be 1.47% (1979: 0.54%). Over 40% of the stones were passed spontaneously. CONCLUSION: There has been a marked increase in the prevalence and incidence of urolithiasis in Germany within the last 22 years. This probably results from improvements in clinical-diagnostic procedures, changes in nutritional and environmental factors and a general apathy towards metabolic clarification and metaphylaxis.

Adult↗

PubMed1990

Idiopathic hypercalciuria: association with isolated hematuria and risk for urolithiasis in children. The Southwest Pediatric Nephrology Study Group.

A prospective multicenter study was designed to determine the frequency and prognostic importance of hypercalciuria in children with hematuria. Urinary calcium excretion was examined in 215 patients with unexplained isolated hematuria (no proteinuria, urolithiasis, infection or systemic disorder). Hypercalciuria (urinary calcium excretion greater than 4 mg/kg/day) was identified in 76 patients (35%). Compared to patients with normal urinary calcium excretion, children with hematuria and hypercalciuria were characterized by male preponderance, white race, family history of urolithiasis, gross hematuria and calcium oxalate crystals. Renal biopsies were performed in 10 patients with urinary calcium excretion 0.4 to 2.5 mg/kg/day; three had IgA glomerulonephritis, three had glomerular basement membrane thinning, one had proliferative glomerulonephritis and three were normal. Renal biopsies in three patients with hypercalciuria showed focal segmental glomerulosclerosis, hereditary nephritis or no abnormalities. Oral calcium loading tests showed renal hypercalciuria in 26 patients, absorptive hypercalciuria in 15 patients and were not diagnostic in 35 patients. Serum parathyroid hormone, bicarbonate and phosphorus and urinary cyclic adenosine monophosphate concentrations were similar in the three groups of hypercalciuric patients. Urinary calcium excretion after one week of dietary calcium restriction was higher (5.8 mg/kg/day) in renal hypercalciuria than in other hypercalciuric patients (3.4 mg/kg/day), P less than 0.01. One to four years follow-up was available for 184 patients. Eight of 60 hypercalciuric patients developed urolithiasis or renal colic compared to 2 of 124 patients with normal urinary calcium excretion (P less than 0.001). Hypercalciuria is commonly associated with isolated hematuria and represents a risk factor for future urolithiasis in children with hematuria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed2000

Characteristics of pediatric urolithiasis in south-east Anatolia.

BACKGROUND: Urolithiasis is endemic in Turkey and characteristics of urolithiasis vary in different regions of the world. The aim of the present study was to evaluate the etiological and clinical characteristics and course of pediatric urolithiasis in south-east Turkey. METHODS: The study population consisted of 81 children (52 girls) with urolithiasis at a mean age of 6.2 +/- 4.2 years who were followed up for 1-32 months. RESULTS: Metabolic disorders, anatomical defects and infection stones were found to be the etiological factor in 34.6, 29.6 and 22.2% of patients, respectively, while 13.6% of patients were considered idiopathic. Of all patients, 28.4% were admitted with acute renal failure (ARF) and 72.8% had urinary tract infection. Recurrence was seen in 19.8% of patients at presentation. The localization of the stone was found to be in the upper urinary tract, the lower urinary tract or both in 65.4, 14.8% and 17.3% of patients, respectively. Patients with multiple and bilateral stones had a higher risk for ARF than the others. The risk for chronic renal failure was significantly higher in children with multiple, bilateral or recurrent stones and with ARF at presentation. CONCLUSIONS: Early diagnosis and management of renal stones and urinary tract infections is necessary to prevent the development of ARF or chronic renal failure and to improve the quality of a patient's life.

Acute Kidney Injury↗

PubMed2000

The management of paediatric urolithiasis.

OBJECTIVE: To evaluate the efficacy and safety of the management of paediatric urolithiasis by extracorporeal shock wave lithotripsy (ESWL), endoscopic ureterolithotomy, percutaneous nephrolithotomy (PCNL) and open nephrolithotomy. PATIENTS AND METHODS: In a 3-year period (1997-1999), 59 children were treated for urolithiasis and underwent a total of 79 procedures. Thirty-two ESWL sessions were performed in 23 children (mean age 7.4 years, median 6.0). PCNL was undertaken in 30 renal units in 25 children (mean age 6.4 years, median 4.0). Eight patients (mean age 7.8 years, median 5) underwent 17 ureteroscopic procedures, six of which involved the use of a holmium laser. Three children with staghorn calculi underwent open nephrolithotomy under conditions of renal ischaemia and hypothermia. RESULTS: Of the 23 children treated using ESWL, 21 (91%) became stone-free; 17 underwent one ESWL session (74%), three had two sessions and three (13%) had three sessions. All eight patients who underwent ureteroscopy became stone-free. Four patients in whom the stone could not be reached by ureteroscopy initially had a JJ stent inserted, and the stone and stent subsequently removed. Stones were cleared using PCNL in 27 of 30 renal units (90%); three patients who had residual stone fragments were rendered stone-free by ESWL. Two of three children undergoing open nephrolithotomy were stone-free after surgery and the remaining one rendered stone-free with ESWL. Metabolic evaluation showed that 25 of 45 children (55%) had a urinary infection, eight (18%) had hyperoxaluria, three (7%) had hypercalciuria, two (4%) had cystinuria, and no identifiable cause was found in seven (16%). Treatment by a single modality rendered 52 of the 59 children (88%) stone-free; when the different modalities were combined, 57 of 59 patients (97%) were cleared of their stones. CONCLUSIONS: Technological advances in ESWL, ureteroscopy and PCNL have had a significant effect on the management of urolithiasis in children, allowing a safe and successful outcome. The comprehensive care of children with urolithiasis should include a full metabolic evaluation. Anatomical anomalies contribute to the complexity of many cases, necessitating a close liaison between adult and paediatric urologists, nephrologists and radiologists to optimize stone management in children.

Adolescent↗

PubMed2006

[Extended metabolic diagnosis of urolithiasis].

PURPOSE: In Germany, urolithiasis, with a frequency of 5 % and a continuously increasing incidence, must be considered as a widespread disease. Ever growing socio-economic expenses have become the focus of attention. The present treatment strategies provide only limited support for the practitioner in evaluating the often complex causes of urolithiasis and in assessing the chosen treatment. A successful treatment with minimal effort requires a general improvement of existing options in prophylaxis as well as metaphylaxis of urolithiasis. For this purpose, detailed examination and interpretation of a stone-former's urinary composition are essential. MATERIAL AND METHODS: The following two novel and significant methods with rapid and uncomplicated application procedures are presented: 1) The easy-to-perform and accurate determination of the calcium oxalate crystallisation risk from a urine sample using the BONN risk index (BRI) for the most frequently occurring stone type (75 %). 2) Consideration of the chemical depletion of lithogenic components in a urine sample due to in-vivo growing uroliths. This phenomenon, the so-called depletion effect, can be of considerable clinical relevance due to possible determination of false normal urinary parameters. RESULTS: This review article explains the theoretical background of these methods and the many applications of the novel methods in practice. CONCLUSIONS: New strategies in stone prevention can help to reduce the extent of urolithiasis in a patient. The BRI enables the practitioner to optimise patient treatment without major effort. Consideration of the stone growth-related alteration of composition improves the interpretation of urine analysis.

Calcium Oxalate↗

PubMed1997

Urolithiasis in patients with Hirschsprung's disease.

Although patients with Hirschsprung's disease (HD) carry some factors that increase the risk of urolithiasis this fact seems to be underestimated. Among 302 patients with HD, four patients (1.32%) with urolithiasis were encountered. Since factors increasing the risk of urolithiasis such as urinary tract infection, constipation, vesicoureteral reflux, enteric resections and malabsorption may be encountered during the course of HD, an increased risk of urolithiasis in these patients should be expected.

Bacteriuria↗

PubMedDate not supplied

A model of suture-induced urolithiasis with urographic control in the bladder of the rat.

The characteristics of a model of urolithiasis in the bladder of male Wistar rats were evaluated. Two techniques were compared: one knot of suture material through the bladder wall, or 15-throw knots inside the bladder. Rats were randomly assigned to one of six groups, according to the technique and suture material used (polyester, silk, or chromic catgut). An excretory urogram was performed at days 30, 60, and 90. At the moment of positive radiographic diagnosis, animals were sacrificed and stones were obtained. All rats were sacrificed at day 90 regardless of the x-ray results. Variables evaluated were average days to a positive urogram, average weight of all uroliths, and percentage of animals developing urolithiasis throughout the study. There were no statistical differences between groups for the average weight of stones, which ranged from 0.008 to 1.502 g for individual cases. All three materials were more lithogenic with the 15-throw knot inside technique. No significant differences were detected for lithogenesis criteria between suture materials. X-ray dispersion spectroscopy evidenced calcium phosphate composition of two stones from chromic catgut, and magnesium phosphate composition of two stones from chromic catgut, two from silk, and two from polyester. Neo-epithelization over the suture was confirmed microscopically in bladders with the one-throw technique. We conclude that (1) this is an effective model of urolithiasis, with predictability in time, composition, and amount of stone formation; (2) the presence of more suture material inside the bladder is more lithogenic; and (3) excretory urograms are highly sensitive and specific for the noninvasive diagnosis of bladder urolithiasis.

Animals↗

PubMed2005

Therapeutic action of citrate in urolithiasis explained by chemical speciation: increase in pH is the determinant factor.

BACKGROUND: The therapeutic action of citrate in the management of calcium oxalate urolithiasis has been attributed to the depletion of free calcium ions by complexation of the latter by citrate itself. However, little attention has been given to the nature of such complexes and the chemical conditions which control their formation because it is very difficult to measure them in solution. We therefore modelled the theoretical formation of these complexes in urine following administration of a citrate-containing preparation, using a powerful speciation program, JESS (Joint Expert Speciation System), which has been widely used to model metal-ligand equilibria in biological systems but which has hitherto not been applied in urolithiasis research. This program has an extensive database of thermodynamic constants and is able to calculate mixed ligand speciation. METHODS: Urine data obtained before and after citrate administration in four groups of subjects (male and female normals and stone formers) were used as input for JESS to calculate the speciation of calcium, citrate and oxalate. The program was also used to examine the effects of varying different urinary components on the nature and concentration of the various species. RESULTS: The speciation predicted the formation of a key calcium-citrate-phosphate species (previously unreported in urolithiasis research), which accounts for a significant percentage of the complexation of the free calcium. Moreover, the formation of this complex was found to be dependent on an increase in urinary pH rather than on an increase in urinary citrate concentration per se. CONCLUSION: The therapeutic action of citrate in the management of calcium oxalate urolithiasis is due to the formation of a pH dependent calcium-citrate-phosphate complex which reduces the concentration of the free calcium ion species, thereby reducing the risk of stone formation.

Calcium Oxalate↗

PubMed2006

Urolithiasis in patients with spinal cord injuries: risk factors, management, and outcomes.

PURPOSE OF REVIEW: Despite major advances in the urological care of spinal cord injury patients, the incidence of urolithiasis has not changed. Although the incidence of kidneys lost to staghorn calculus disease has decreased considerably, stone disease is still a significant cause of morbidity and concern. The purpose of this review is to summarize the risk factors for the development of stone diseases in the spinal cord injury patient population and present the outcomes of current endourologic treatment modalities. RECENT FINDINGS: Recurrent urinary tract infections, indwelling catheters, vesicoureteral reflux, and immobilization hypercalcuria are a few of the major risk factors for the development of urolithiasis among spinal cord injury patients. Retrograde endourologic techniques are often not possible to address stone disease due to lower extremity contractures, spinal curvature, and pelvic tilt. Extracorporeal shockwave lithotripsy success rates vary from 50 to 90%, but clearance rates are often delayed. Success rates for percutaneous nephrolithotomy match those quoted in the general population ( > 90%), but at the expense of a higher rate of complications (6-20%). Meticulous planning with regard to appropriate prophylactic antibiotics and body position will maximize efficacious outcomes. SUMMARY: Early identification and treatment of urolithiasis in spinal cord injury patients will aid in preserving renal function and minimizing associated complications. Despite variation in common urological practices between spinal cord injury units and the lack of clear cut guidelines for follow-up, the increased incidence of risks associated with urolithiasis lends support for routine genitourinary imaging in order to identify and treat those individuals at highest risk.

Humans↗

PubMed2004

Urolithiasis after kidney transplantation in pediatric recipients: a single center report.

BACKGROUND: Urolithiasis occurs in approximately 6% of adult kidney transplant (KTx) recipients. Limited data are available on urolithiasis after pediatric KTx. We report the incidence, management of, and risk factors for stone development in children after KTx. METHODS: We reviewed the medical records of 399 children who received KTx at our center between September 1986 and January 2003. Transplant outcomes were compared in stone formers and controls. RESULTS: Twenty (5%) patients, age 9+/-5 (X +/- SD) years, developed stones over the follow-up period (74+/-53 months). Time to stone presentation was 19+/-22 months post-KTx. Presenting features were urinary tract infection (UTI), 8; gross hematuria, 5; microscopic hematuria, 2; dysuria without infection, 6; difficulty voiding, 3; and silent stones, 2. Stones were removed by cystoscopy in 11 (55%) patients. Stone composition was determined in 11 patients: calcium phosphate (55%), calcium oxalate (18%), mixed calcium phosphate and oxalate (9%), and struvite (18%). Factors predisposing to stones in study patients included suture retention (n = 4), elevated urinary calcium excretion (n = 2), recurrent UTI (n = 2), and urinary stasis (n = 2). The incidence of UTI was higher (P = 0.003) and of acute rejection was lower (P = 0.02) in stone patients compared with controls. Patient and graft survival rates and the incidence of chronic rejection did not significantly differ between study patients and controls (P = NS). CONCLUSIONS: Urolithiasis is not uncommon in pediatric KTx patients. Factors associated with post-KTx urolithiasis include retention of suture material, recurrent UTI, hypercalciuria, and urinary stasis. Treatment is associated with excellent outcome and low recurrence rate.

Adolescent↗

PubMedDate not supplied

Urinary bladder marsupialization for treatment of obstructive urolithiasis in male goats.

OBJECTIVES: To describe a surgical procedure for urinary bladder marsupialization and to report the results obtained from its use in the treatment of obstructive urolithiasis in male goats. STUDY DESIGN: Retrospective evaluation. ANIMALS OR SAMPLE POPULATION: Male goats with obstructive urolithiasis. METHODS: Medical records of male goats that had urinary bladder marsupialization for the treatment of obstructive urolithiasis were reviewed. Data retrieved from the medical records included signalment, postoperative treatment, duration of hospitalization, and short-term and long-term complications. Median values for measured variables were calculated. RESULTS: A total of 18 of 19 goats survived. Urinary flow was re-established in all 19 goats at the conclusion of surgery. Short-term postoperative complications (bladder mucosal prolapse and death) were observed in 2 goats. Long-term postoperative complications (cystitis and fibrotic stomal closure) occurred in 2 animals. Median duration of hospitalization was 4 days. At the time of follow-up, mild urine scald was reported for all goats. Clinical signs of upper urinary tract disease or obstruction were not reported. A total of 15 of 17 owners were satisfied with the procedure. CONCLUSIONS: Urinary bladder marsupialization provided long-term resolution of urinary outflow obstruction in all goats with acceptable morbidity. CLINICAL RELEVANCE: Urinary bladder marsupialization is a procedure that provides a good prognosis for long-term resolution of obstructive urolithiasis in male goats.

Animals↗

PubMed2005

Cellular and molecular gateways to urolithiasis: a new insight.

Urolithiasis is a relevant clinical problem in everyday practice with a subsequent burden for the health system. Urolithiasis is classically explained as the derangement in the process of biomineralization involving the equilibrium between promoters and inhibitors of crystallization: a deficit of one or several inhibitors or an excess of one or several promoters plays a pivotal role in the stone formation. The revolutionary introduction of the molecular biology in medicine has given a new insight in urolithiasis too. Genetic factors have also been postulated to play an important role. A review of the current knowledge on urolithiasis based upon a molecular and genetic approach is reported.

Animals↗

PubMed1996

Childhood urolithiasis: urological management of upper tract calculi in the era of extracorporeal shock-wave lithotripsy.

OBJECTIVE: To evaluate the management of urolithiasis in children since the development of extracorporeal shock-wave lithotripsy (ESWL). METHODS: Between 1988 and 1994, 37 children, aged from 2 to 15 years (mean 10), with upper tract urolithiasis were evaluated and treated. Lithogenic metabolic disorders or anomalies of the urinary tract were present in 11 children (30%) Urolithiasis was multiple in 9 cases and bilateral in 2 cases. A total of 47 renal (30) or ureteral (17) stones were managed, of which 5 were partial or complete staghorn calculi. Initial treatment was surgery in 4 cases (1 nephrectomy, partial nephrectomy and 2 pyelolithotomies) and piezoelectric ESWL in 43 cases. RESULTS: The overall ESWL success rate was 82.2%, with auxillary endoscopic procedures in 3 cases. ESWL failures required surgical stone removal in 5 cases, endoscopic ureterolithotripsy in 1 case and electrohydraulic ESWL in 1 case. Residual fragments after pyelolithotomies were also treated by ESWL. CONCLUSION: ESWL is the mainstay of treatment of childhood upper tract urolithiasis, but other therapeutic methods retain specific indications. Its application requires great vigilance and its long-term effects are uncertain. It is therefore important to rule out any underlying pathology and where possible to prevent further stone formation.

Adolescent↗

PubMed2002

Urethroscopy and laser lithotripsy for the diagnosis and treatment of obstructive urolithiasis in goats and pot-bellied pigs.

OBJECTIVE: To explore the use of urethral endoscopy and laser lithotripsy in the diagnosis and management of urolithiasis in goats and pot-bellied pigs. DESIGN: Prospective clinical study. ANIMALS: 16 male goats and 6 male pot-bellied pigs with dysuria. PROCEDURE: Abdominal ultrasonography and urethral endoscopy were performed on all 22 animals. Endoscopic-guided holmium:yttrium-aluminum-garnet laser lithotripsy was performed in 3 goats and 2 pot-bellied pigs. RESULTS: Urolithiasis was identified in 15 goats and 5 pot-bellied pigs. Primary urinary bladder paralysis and cystitis were identified in the remaining pot-bellied pig and goat. Mean bladder diameters of obstructed small- and large-breed goats were 7 and 9.5 cm, respectively. The mean bladder diameter of obstructed pot-bellied pigs was 9.5 cm. Five of 20 animals with obstructive urolithiasis had severe urethral necrosis or stricture formation at the time of urethroscopy. All of these animals were euthanatized within 6 months because of persistent dysuria. When used, laser lithotripsy successfully fractured the distally located obstructing stones in the 3 goats and 2 pot-bellied pigs. CONCLUSIONS AND CLINICAL RELEVANCE: Urethral endoscopy is useful for evaluating urethral patency in goats and pot-bellied pigs. Examination of the urethral mucosa following relief of urethral obstructions aids in the assessment of the long-term prognosis for urethral stricture. Urethral endoscopy also expands the therapeutic options for management of urolithiasis by providing a route for conducting laser lithotripsy. Laser lithotripsy proved to be safe and effective for clearing distally located calculi refractory to removal by traditional urethral flushing. Lithotripsy application is restricted to calculi lodged in the urethra.

Abdomen↗

PubMed1983

Kidney function of pullets and laying hens during outbreaks of urolithiasis.

Renal function evaluations were conducted on pullets and laying hens during outbreaks of urolithiasis. The following parameters were measured: kidney weights; hematocrits; plasma concentrations of uric acid, calcium, inorganic phosphate, magnesium, sodium, and potassium; urine flow rates; glomerular filtration rates; renal plasma flow rates; urine pH; and relative clearances of inorganic phosphate, calcium, magnesium, sodium, potassium, and para-amino hippuric acid. The adequacy of renal portal perfusion was estimated by timed phenol red extraction. Considerable interindividual variability was noted, presumably due to differences in age and reproductive status. Intraindividual left versus right kidney comparisons also were made, since urolithiasis often is associated with macroscopic lesions of one kidney but not the other. The results indicate that even when gross lesions of only one kidney were present, specific tubular transport processes were similar in both kidneys. Urolithiasis did cause significant alterations in urine flow rates, glomerular filtration rates and renal plasma flow rates. it was concluded that the changes associated with urolithiasis reflect the expected compensatory hypertrophic responses of surviving kidney tissue to a reduction of renal mass. The physiological impact of this form of kidney damage appears to arise from reduced renal mass rather than from inappropriate renal handling of minerals or electrolytes.

Animals↗

PubMed1985

Urolithiasis in pullets and laying hens: role of dietary calcium and phosphorus.

A study was conducted to test the independent and combined effects of high dietary calcium and low available phosphorus on the incidence of urolithiasis in pullets and laying hens. One thousand Single Comb White Leghorn pullets were divided into four diet treatment groups beginning at 50 days of age. A normal calcium (1%), normal available phosphorus (.6%) diet (NCNP) was fed to control pullets. Other pullet groups were fed a high calcium (3.25%), normal available phosphorus (.6%) diet (HCNP), a normal calcium (1%), low available phosphorus (.4%) diet (NCLP), or a high calcium (3.25%), low available phosphorus (.4%) diet (HCLP). At 18 weeks of age, 368 pullets were necropsied. One percent of the HCNP group and 14% of the HCLP group developed urolithiasis. Urolithiasis was not found in pullets raised on the NCNP and NCLP diets. The remaining pullets were transferred to laying cages and were fed a commercial layer ration until they were 51 weeks old. None of the hens raised on the NCNP diet, 12% of the hens raised on the HCNP diet, 2% of the hens raised on the NCLP diet, and 14% of the hens raised on the HCLP diet had urolithiasis. Renal function studies were performed on 18-week-old pullets and 51-week-old hens. Pullets raised on the HCLP diet had significantly higher urine pH, significantly lower fractional inorganic phosphate excretion, and significantly higher fractional calcium excretion when compared with pullets raised on the other diet treatments. The profound effect of the HCLP diet on renal calcium and phosphorus excretion in pullets was not retained in the hens.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗