The distinction of cellular blue nevi (CBN) with atypical features ["atypical" CBN (ACBN)] from conventional CBN and malignant melanomas related to or derived from CBN remains a difficult problem. Here, we report on the diagnosis of various cellular blue melanocytic neoplasms by 14 dermatopathologists who routinely examine melanocytic lesions. Three parameters were assessed: (1) for between rater analyses, we calculated interobserver agreement by the kappa statistic (regardless of whether the diagnosis was correct). (2) For each individual lesion, we reported whether a majority agreement (>50%) was reached and, if so, whether the majority agreed with the gold standard diagnosis, derived from standardized histopathologic criteria for melanoma, definitive outcome such as metastatic event or death of disease, or disease-free follow-up for > or =4 years. (3) For the individual pathologists, we calculated sensitivity and specificity for each type of lesion. The study set included 26 melanocytic lesions: (1) 6 malignant melanomas developing in or with attributes of CBN; (2) 11 CBN with atypical features and indeterminate biologic potential (ACBN); (3) 8 conventional CBN; and (4) 1 common BN. The kappa values for interrater agreement varied from 0.52 (95% confidence interval 0.45, 0.58) for melanoma to 0.02 (0.05, 0.08) for ACBN and 0.20 (0.13, 0.28) for CBN. The kappa for all lesions was 0.25 (0.22, 0.28). The pathologists' sensitivities were 68.6% (61.0%, 76.1%) for melanoma, 33.1% (21.0%, 45.2%) for ACBN, and 44.6% (29.0%, 60.3%) for CBN. The specificities were 65.7% (55.8%, 75.6%) for melanoma, 84.7% (77.3%, 92.2%) for ACBN, and 89.9% (82.7%, 97.1%) for CBN. Overall, greater than 50% of the pathologists agreed and were correct in their diagnosis 38.5% (10 lesions) of the time. There was a majority agreement, but with an incorrect diagnosis, another 26.9% (7 lesions) of the time. Six of the 7 majority agreements with an incorrect diagnosis were for ACBN lesions. In summary, the results of our study indicate that there is substantial confusion and disagreement among experienced histopathologists about the definitions and biologic nature of cellular blue melanocytic neoplasms particularly those thought to have atypical features ("atypical" CBN).

Primary vesicoureteral reflux (VUR) is the most common congenital anomaly of the kidney and the urinary tract, and it is a major risk factor for pyelonephritic scarring and CKD in children. Although twin studies support the heritability of VUR, specific genetic causes remain elusive. We performed a sequential genome-wide linkage study and whole-exome sequencing in a family with hereditary VUR. We obtained a significant multipoint parametric logarithm of odds score of 3.3 on chromosome 6p, and whole-exome sequencing identified a deleterious heterozygous mutation (T3257I) in the gene encoding tenascin XB (TNXB in 6p21.3). This mutation segregated with disease in the affected family as well as with a pathogenic G1331R change in another family. Fibroblast cell lines carrying the T3257I mutation exhibited a reduction in both cell motility and phosphorylated focal adhesion kinase expression, suggesting a defect in the focal adhesions that link the cell cytoplasm to the extracellular matrix. Immunohistochemical studies revealed that the human uroepithelial lining of the ureterovesical junction expresses TNXB, suggesting that TNXB may be important for generating tensile forces that close the ureterovesical junction during voiding. Taken together, these results suggest that mutations in TNXB can cause hereditary VUR.

We have constructed a 384-channel parallel microfluidic cytometer (PMC). The multichannel architecture allows 384 unique samples for a cell-based screen to be read out in approximately 6-10 min, about 30-times the speed of a conventional fluorescence-activated cytometer system (FACS). This architecture also allows the signal integration time to be varied over a larger range than is practical in single-channel FACS and is suitable for detection of rare-cells in a high background of negatives. The signal-to-noise advantages have been confirmed by using the system to count rare clonal osteocytes in the most difficult early stages of an expression-cloning screen for the carboxy-terminal parathyroid hormone receptor (CPTHR). This problem requires finding several dozen positive cells in a background of one million negatives. The system is automated around a scanning laser confocal detector and a 96-tip robotic pipettor and can maintain in vitro cultures on-system in 384-well plates. It is therefore directly practical for biology applications using existing high-throughput culture facilities. The PMC system lends itself to high-sample-number cytometry with an unusual capability for time synchronization and rare-cell sensitivity. A limited ability to handle large sample numbers has restricted applications of single-channel FACS in combinatorial cell assays; therefore the PMC could have a significant application in high-throughput screening.

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