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Melamine, a widely used chemical found in many products in daily use, became a public health concern due to melamine-associated urinary stone formation in children. In adults, it is still unknown whether low-dose melamine exposure may also cause urolithiasis. To address this question, we studied 211 Taiwanese patients diagnosed with calcium urolithiasis and 211 age- and gender-matched controls. All patients completed a detailed questionnaire and provided blood and urine samples for biochemical analysis. Urinary melamine concentrations were measured by triple-quadrupole liquid chromatography tandem mass spectrometry. Compared with those whose urinary melamine levels were below the detection limit of the method, patients with urinary melamine levels of up to 3.11  ng/ml and those with levels of ≥3.12  ng/ml had 3.01- and 7.64-fold increased risk, respectively, of calcium urolithiasis after adjusting for educational level, fluid intake, cigarette smoking, betel quid chewing, alcohol drinking, urinary uric acid, calcium, creatinine, and estimated creatinine clearance rate. The population attributable risk of calcium urolithiasis averaged 50% when melamine was detected in the urine, after considering other covariates. MALDI-TOF mass spectrometry detected melamine in the stones of nine representative patients who had measurable urinary melamine levels. Thus, low-dose melamine exposure can play an important role in calcium urolithiasis in Taiwanese adults.

Metastatic renal cell carcinoma (RCC) is highly resistant to conventional systemic treatments, including chemotherapy, radiotherapy and hormonal therapies. Previous studies have shown over-expression of EGFR is associated with high grade tumors and a worse prognosis. Recent studies suggest anticancer therapies targeting the EGFR pathway have shown promising results in clinical trials of RCC patients. Therefore, characterization of the level and localization of EGFR expression in RCC is important for target-dependent therapy. In this study, we investigated the clinical significance of cellular localization of EGFR in human normal renal cortex and RCC. RCC and adjacent normal kidney tissues of 63 patients were obtained for characterization of EGFR expression. EGFR protein expression was assessed by immunohistochemistry on a scale from 0 to 300 (percentage of positive cells × staining intensity) and Western blotting. EGFR membranous staining was significantly stronger in RCC tumors than in normal tissues (P < 0.001). In contrast, EGFR cytoplasmic staining was significantly higher in normal than in tumor tissues (P < 0.001). The levels of membranous or cytoplasmic EGFR expression in RCC tissues were not correlated with sex, tumor grade, TNM stage or overall survival (P > 0.05). These results showed abundant expression of membranous EGFR in RCC, and abundant expression of cytoplasmic EGFR in normal tissues. EGFR expression in RCC was mostly located in the cell membrane, whereas the EGFR expression in normal renal tissues was chiefly seen in cytoplasm. Our results suggest different locations of EGFR expression may be associated with human renal tumorigenesis.

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Aim: The aim of this study was to evaluate the clinical characteristics of uric acid urolithiasis and how the presentation differs between urolithiasis of the upper urinary tract (UUT) compared with urolithiasis of the bladder. We attempted to evaluate the importance of local vs. systemic factors in the formation of bladder uric acid stones. Patients and Methods: The medical records of 77 consecutive patients with uric acid urolithiasis from January 2004 to December 2006 were reviewed retrospectively. In all patients, histories were recorded, and physical examinations, renal function tests and urine analysis were done. The features of the treated stones were recorded, and the chemical composition was analyzed by computed Fourier transform infrared spectrophotometry. Results: Among 77 patients with uric acid stones, 66 were male and 11 were female (ratio of 7.6:1). Mean age was 59.50 ± 10.46 years. Of the stones, 55 (71.4%) were located in the UUT (UUT group) and 22 (28.6%) in the bladder (bladder group). Multiple presentations of urolithiasis at diagnosis were found in 56 (72.7%) patients. The mean values of serum creatinine and uric acid were 148.28 ± 70.69 and 443.33 ± 95.91 μmol/l, respectively. Mean body mass index (BMI) was 26.78 ± 2.90, and 72.7% of patients were overweight or obese. Mean urinary pH was 5.39. No significant differences existed between the 2 groups in regard to gender, BMI, urinary pH, stone nature, or presence of hypertension, gout, and/or urinary tract infections. In the bladder group, the incidence of benign prostate hyperplasia was significantly increased, and the incidence of diabetes mellitus was significantly lower, as were levels of serum uric acid and creatinine. Conclusions: Uric acid urolithiasis was predominant in men in this study. These patients tended to be obese or overweight, with multiple stone presentations and low urinary pH. Furthermore, the bladder uric acid stone group had significantly lower levels of serum creatinine and uric acid, and lower percentages of diabetes mellitus but higher incidences of benign prostate hyperplasia in comparison with the UUT group. The local factor seems more important than the systemic factor in the formation of bladder uric acid stone.

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