Distribution of cardiac troponin I in the Japanese general population and factors influencing its concentrations.

BACKGROUND: The 99th percentile of cardiac troponin I level in the general population is accepted as the cut-off for the diagnosis of acute myocardial infarction (AMI). However, it is not clear whether the cut-offs derived in racially and geographically different populations are applicable in Japan. METHODS: Troponin I was determined using the Abbott ARCHITECT STAT high-sensitive troponin I immunoassay in 698 apparently healthy individuals who visited the Japanese Red Cross Medical Center for a health checkup. RESULTS: The 99th percentile of the hsTnI in the overall population was 22.5 (95% confidence interval (CI), 16.8-36.6) pg/mL, 17.7 (95% CI 12.0-22.8) pg/mL for females and 30.6 (95% CI 17.1-53.4) pg/mL for males. The median of the hsTnI in the overall population was 3.2 (95% CI, 3.0-3.3) pg/mL, 2.6 (95% CI 2.4-2.8) pg/mL for females and 4.0 (95% CI 3.8-4.3) pg/mL for males. The age and gender had a significant influence on these values. The troponin I level also showed significant associations with the body mass index (BMI), the gamma glutamyl transferase (GGT), lactate dehydrogenase (LDH), estimated glomerular filtration rate (eGFR), and cardiac abnormalities by electrocardiography (ECG) but not with the high-sensitive C-reactive protein (hsCRP) level. CONCLUSIONS: The 99th percentiles of the troponin I measured in the general population in Japan were comparable as the ones derived in the US, Germany, and Singapore. The troponin I level was dependent on the gender, age, BMI, and cardiac abnormalities found by ECG but not by the hsCRP level.

Multiple cystic sphere formation from PK-8 cells in three-dimensional culture.

Three-dimensional (3D) culture of cancer cells mimics the in vivo environment. Recently, we reported that pancreatic ductal adenocarcinoma (PDAC) cell lines with epithelial and mesenchymal features formed differently shaped spheres in 3D culture. However, only PK-8 cells, the epithelial PDAC cell line with the highest E-cadherin expression among the eight PDAC cell lines, formed multiple cystic spheres in 3D culture. Optical coherence tomography revealed interconnected cysts inside the spheres. A weak inter-cellular adhesion, individual cell degeneration, necrosis, and secretory granules in the cytoplasm were observed in the PK-8 spheres using electron microscopy. The expression of MUC1, MUC5AC, and amylase was increased in PK-8 cells in the 3D culture compared with that in 2D culture. These findings suggest that highly E-cadherin-expressing epithelial PK-8 cells form multiple cystic spheres, which may be promoted by enhanced mucin and amylase synthesis in 3D culture.

Phenotype of regenerative epithelium in idiopathic interstitial pneumonias.

The epithelial alteration in interstitial pneumonias is one of the repair processes at the sites of disease activity. Regenerative epithelial cells may participate in remodeling of the lung. To determine the phenotype of regenerative epithelial cells in usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP), the expression of Clara cell 10KD protein (CC10), cytokeratin (CK) 14 and 17, surfactant apoprotein (SP)-A, KL-6/MUC1, transforming growth factor (TGF) beta2 were examined in 25 patients with UIP, 9 patients with NSIP and normal lung tissues from 10 patients with lung cancer. In honeycomb lesions of UIP, non-ciliated columnar cells mainly expressed CC10, cuboidal cells expressed CC10, CK17, CK14 and SP-A in descending order. Fibroblastic foci are covered by CK17, CK14, CC10, and a few SP-A positive flattened or cuboidal cells. Regenerative epithelium in NSIP mainly comprised cuboidal cells expressing SP-A, CC10 and CK17. KL-6 was more remarkably expressed in cuboidal and non-ciliated columnar cells both in UIP and NSIP. Expression of TGFbeta2 was observed in cuboidal and flattened epithelium. In severe fibrotic areas, CC10 expressing cells were more prominent, while SP-A positive cells were more prominent in less fibrotic areas. Regenerative epithelial cells in remodeling area in UIP may be derived from bronchiolar basal cells and Clara cells, while most of those in NSIP may be derived from type II pneumocytes. The different origin of regenerative epithelium may reflect the severity and extent of the injury and the degree of consequent fibrosis in UIP and NSIP.