Automated urinalysis combining physicochemical analysis, on-board centrifugation, and digital imaging in one system: A multicenter performance evaluation of the cobas 6500 urine work area

BACKGROUND

We evaluated the analytical performance of the fully automated cobas® 6500 urine work area and its automated components-cobas u 601 and cobas u 701.

DESIGN AND METHODS

The study was conducted at three European centers using un-centrifuged surplus routine urine samples; all measurements were performed within 2 h of sample collection. Precision, sample carry-over, and method comparisons were evaluated per Clinical and Laboratory Standards Institute guidelines. Method comparisons: cobas u 601 versus Urisys 2400 and cobas u 411 urine test strips; and cobas u 701 versus KOVA® visual microscopy and iQ200 analyzer. Operability and functionality were assessed using questionnaires.

RESULTS

Precision of the entire cobas 6500 system was within predefined acceptance limits and no significant carry-over was observed. Erythrocytes, leukocytes, nitrites, and protein were in good agreement (≥93%) with cobas u 411 reflectometry. High correlation was shown between the cobas u 701 analyzer and KOVA visual microscopy for red blood cells (RBC; slope, 0.89; Pearson's r, 0.95) and white blood cells (WBC; slope, 0.96; Pearson's r, 0.96), demonstrating equivalence of test results. The 97.5% percentile reference values on the cobas u 701 analyzer were 5.3 cells/μL (RBC) and 6.2 cells/μL (WBC). The cobas 6500 system showed good sensitivity for small bacteria (>1 μm) and pathological casts, and the user interface, maintenance wizards, and system design were highly rated by operators.

CONCLUSIONS

The fully automated workflow, high precision, and high throughput of the cobas 6500 system have the potential to facilitate standardization of urine screening.

Expression and immunohistochemical localization of leptin in human periapical granulomas

BACKGROUND

Leptin, initially described as an adipocyte-derived hormone to regulate weight control, is expressed in normal and inflamed human dental pulp, being up-regulated during pulp experimental inflammation. Leptin receptor (LER) has been identified in human periapical granulomas. The aim of this study was to analyze and characterize the expression of leptin in human periapical granulomas.

MATERIAL AND METHODS

Fifteen periapical inflammatory lesions were obtained from extracted human teeth and teeth which underwent periapical surgery. After their morphological categorization as periapical granulomas and gradation of the inflammatory infiltrate, they were examined by immunohistochemistry using human leptin policlonal antibodies. Leptin mRNA expression was also determined by quantitative real-time PCR (qRT-PCR) and the amount of leptin protein was analyzed by immunoblot.

RESULTS

All periapical lesions exhibited the characteristic of chronic granulomatous inflammatory process with inflammatory infiltrate grade III. Leptin+ cells were detected in 13 periapical granulomas (86.6%). The median number of Leptin+ cells in periapical granulomas was 1.70 (0.00-7.4). Amongst the inflammatory cells in the periapical granulomas, only macrophages were reactive to leptin antibodies. Western blot analysis revealed the presence in all samples of a protein with apparent molecular weight of approximately 16 kDa, corresponding to the estimated molecular weights of leptin. The expression of leptin mRNA was confirmed by qRT-PCR analysis and the size of the amplified fragment (296 bp for leptin and 194 bp for cyclophilin) was assessed by agarose gel electrophoresis.

CONCLUSIONS

For the first time, it has been demonstrated that human periapical granuloma expresses the adipokine leptin.