OBJECTIVETo determine the prevalence of urolithiasis in young children fed infant formula (IF) contaminated with melamine, and the association between IF consumption and urolithiasis.

DESIGNA total of 2 733 children < or = 3 years of age on September 1, 2008 in two townships of Gansu Province, China were studied. Cases of urolithiasis were diagnosed by ultrasonography. Milk product consumption was determined by their caregivers. Remaining IF samples were tested for melamine and cyanuric acid.

RESULTSOf 2 733 eligible children in the two townships, 2 186 (80%) were enrolled in our study. Overall, 16.6% (362) of 2 186 children had urolithiasis. The prevalence was 24.6% in children exclusively fed Sanlu brand IF, 9.7% in those fed other IF, and 8.5% in those fed exclusively on other milk products. For children exclusively breast-fed, no urolithiasis was found (P < 0.05). The prevalence of urolithiasis was 11.4% in children fed 400 g of Sanlu IF, rising to 37.5% in children fed over 25 600 g. Of 48 Sanlu IF samples, 91.7% contained melamine (median = 1 800 ppm; range = 45-4 700) and 66.7% contained cyanuric acid (median = 1.2 ppm; range = 0.4-6.3). Melamine was also detected in 22.2% of 36 other brand IF (median = 27.5 ppm, range = 4-50).

CONCLUSIONSUrolithiasis was associated with melamine-contaminated IF. Although one product caused most morbidity, other milk products may have also contributed to the outbreak.

Child, Preschool ; Data Collection ; Food Contamination ; Humans ; Infant Food ; analysis ; Triazines ; toxicity ; Urolithiasis ; chemically induced

Female ; Food Contamination ; Humans ; Infant ; Infant Formula ; Kidney Calculi ; chemically induced ; diagnosis ; Male ; Triazines ; toxicity

Food Contamination ; Humans ; Infant ; Triazines ; toxicity ; Urinary Calculi ; diagnosis ; etiology ; therapy

Humans ; Infant ; Infant Food ; Infant, Newborn ; Triazines ; toxicity ; Urinary Calculi ; chemically induced

Breast Feeding ; Consumer Product Safety ; Humans ; Infant ; Infant Food ; Nutritional Physiological Phenomena ; Triazines ; toxicity

Melamine (Tripolycyanamide) and its derivatives have recently become a public concern on food safety. To better understand melamine and its major derivative cyanuric acid.literature on their chemical properties, metabolism, biological effects, relevant toxicology studies, and the detection methods is reviewed. Studies indicate that the acute toxicity of melamine and cyanuric acid is low. In mammalian, these compounds are hardly metabolized in vivo and are rapidly eliminated in the urine. When used in large dosage,these compounds demonstrate marked renal toxicity,as well as toxic effect towards heart. The renal toxicity is exemplified by the calculi formation, acute renal failure, and subsequently induced carcinomas of the urinary bladder. Among the tested species, male cats and rats are more prone to be affected by the compounds. The HPLC/MS/MS is becoming the mainstay of the detection methods. Despite of the achieved knowledge on melamine and cyanuric acid, further research is warranted to unveil the mechanism of underlying susceptibility of kidney, to develop better analytic methods,and to explore possible biomarkers for better clinical diagnosis.
Animals ; Carcinogens ; toxicity ; Cats ; Female ; Kidney Diseases ; chemically induced ; Male ; Rats ; Species Specificity ; Triazines ; toxicity ; Ureteral Calculi ; chemically induced

Animals ; Male ; Organ Size ; Rats ; Rats, Sprague-Dawley ; Spermatozoa ; drug effects ; growth & development ; Testis ; drug effects ; Triazines ; toxicity

This study assessed the toxicity of melamine against the unicellular eukaryotic system of Tetrahymena (T.) pyriformis exposed to 0, 0.05, 0.25, 0.5, 2.5, and 5 mg/mL of melamine. Cell growth curves of different cultures, the half maximum inhibition concentration (IC50) value of melamine, and morphological changes in cells were obtained via optical and transmission electron microscopic observation. The effects of eleven melamine concentrations, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 and 5 mg/mL, on protein expression levels of T. pyriformis were examined using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The results showed an obvious inhibitory effect of melamine on the growth of eukaryotic cells. Cell growth dynamics indicated that the IC50 value of melamine on T. pyriformis was 0.82 mg/mL. The cellular morphology was also affected in a concentration-dependent manner, with characteristics of atrophy or cell damage developing in the presence of melamine. The relative contents of the top four main proteins corresponding to peak mass-to-charge ratios (m/z) of 4466, m/z 6455, m/z 6514, and m/z 7772 in the MALDI-TOF-MS spectra were all found to be closely correlated with the melamine concentrations. In conclusion, exposure of eukaryotic cells to melamine could inhibit cell growth, cause changes in cytomorphology and even disturb the expression of proteins in a concentration-dependent manner. The described method of examining four sensitive proteins affected by melamine was also proposed to be used in a preliminary study to identify protein biomarkers in T. pyriformis.
Animal Feed/analysis/toxicity ; Biological Markers/analysis ; Food Additives/analysis/toxicity ; Inhibitory Concentration 50 ; Microscopy, Electron, Transmission ; Protozoan Proteins/analysis ; Spectrometry, Mass, Matrix-Assisted Laser De ; Tetrahymena pyriformis/cytology/*drug effects ; Triazines/*toxicity

OBJECTIVEWe tested whether melamine nephrotoxicity was exacerbated by urate (a typical component of renal stones in humans) in rats with hyperuricemiainduced by the uricase inhibitor, potassium oxonate (Oxo).

METHODSRats were exposed to melamine or Oxo alone or combinations of melamine (200-400 mg/kg) and Oxo (200-600 mg/kg) for 3 consecutive days. Kidney injury was evaluated by renal biochemical functions, histomorphology, and lipid peroxidation. Kidney crystals were analyzed for their composition.

RESULTSNephrotoxicity was minimal in animals administered melamine or Oxo alone, but it was demonstrable in animals administered at least 800 mg/kg of the two compounds combined. All rats in the 400+600 (melamine+Oxo) and 400+400 mg/kg groups and 4 out of 6 in the 200+600 mg/kg group died within 3 days; no rat died in the 200+400 or 200+200 mg/kg group. Dose-dependent renal damage resembling clinical findings in affected patients was observed in rats administered the two compounds. Crystal composition determination revealed the existence of melamine and uric acid in the affected kidneys, resembling human stones.

CONCLUSIONOur findings suggest that uric acid plays a key role in melamine-related kidney injury in humans. Future studies should consider uric acid together with melamine when examining adverse effects in humans.

Animals ; Disease Models, Animal ; Hyperuricemia ; chemically induced ; complications ; Kidney Diseases ; chemically induced ; Lipid Peroxidation ; drug effects ; Male ; Oxonic Acid ; Rats, Wistar ; Triazines ; toxicity

OBJECTIVETo summarize clinical characteristics, diagnosis and treatment of infants with urinary calculus and acute renal failure developed after being fed with melamine tainted formula milk.

METHODSData of infant patients with urinary calculus and acute renal failure due to melamine tainted formula milk admitted to the Beijing Children's Hospital affiliated to the Capital Medical University and the Xuzhou Children's Hospital in 2008 were used to analyze the epidemiological characteristics, clinical manifestations, image features as well as effects of 4 types of therapies.

RESULTSAll the 34 infants with urinary calculus were complicated with acute renal failure, their blood urea nitrogen (BUN) was (24.1 +/- 8.2) mmol/L and creatinine (Cr) was (384.2 +/- 201.2) micromol/L. The chemical analysis on the urinary calculus sampled from 14 of the infants showed that the calculus contained melamine and acidum uricum. The time needed for the four types of therapies for returning Cr to normal was (3.5 +/- 1.9) d for cystoscopy group, (2.7 +/- 1.1) d for lithotomy group, (3.8 +/- 2.3) d for dialysis group, and (2.7 +/- 1.6) d for medical treatment group, which had no statistically significant difference (P = 0.508). Renal failure of all the 34 infants was relieved within 1 to 7 days, averaging (3.0 +/- 1.8) d.

CONCLUSIONMelamine tainted formula milk may cause urinary calculus and obstructive acute renal failure. It is suggested that firstly the patients with urinary calculus complicated with acute renal failure should be treated with dialysis or medication to correct electrolyte disturbances, in particular hyperkalemia, and then relieve the obstruction with available medical and surgical methods as soon as possible. It is observed that the short term prognosis is satisfactory.

Acute Kidney Injury ; diagnosis ; epidemiology ; therapy ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Infant ; Infant Food ; Male ; Triazines ; toxicity ; Urinary Calculi ; diagnosis ; epidemiology ; therapy