Suck Hong Lee

Characterization of K + Channels in the Basolateral Membrane of Rat Tracheal Epithelia

Abstract. To study K+ channels in the basolateral membrane of chloride-secreting epithelia, rat tracheal epithelial monolayers were cultured on permeable filters and mounted into an Ussing chamber system. The mucosal membrane was permeabilized with nystatin (180 μg/ml) in the symmetrical high K+ (145 mm) Ringer solution. During measurement of the macroscopic K+ conductance properties of the basolateral membrane under a transepithelial voltage clamp, we detected at least two types of K+ currents: one is an inwardly rectifying K+ current and the other is a slowly activating outwardly rectifying K+ current. The inwardly rectifying K+ current is inhibited by Ba2+. The slowly activating K+ current was potentiated by cAMP and inhibited by clofilium, phorbol 12-myristae 13-acetate (PMA) and lowering temperature. This is consistent with the biophysical characteristics of ISK channel. RT-PCR analysis revealed the presence of ISK cDNA in the rat trachea epithelia. Although 0.1 mm Ba2+ only had minimal affect on short-circuit current (Isc) induced by cAMP in intact epithelia, 0.1 mm clofilium strongly inhibited it. These results indicate that ISK might be important for maintaining cAMP-induced chloride secretion in the rat trachea epithelia.

Adenocarcinoma of the urachus : CT features

The CT findings of adenocarcinoma of the urachus in three patients were reviewed and correlated with pathologic features. The tumor was composed of two parts: supravesical and intravesical. The supravesical portion showed a cystic appearance with a capsule in the space of Retzius. The intravesical portions invading the dome of the bladder were polypoid and unencapsulated. These findings were consistent with pathologic findings in all three patients.

Preoperative 18F-FDG PET/CT predicts disease-free survival in patients with primary invasive ductal breast cancer.

Background Previous studies have correlated the maximum standardized uptake value (SUVmax) of breast cancer lesions with histological and biological characteristics such as tumor size, histologic grade, or hormonal receptor expression status. However, controversy remains concerning the prognostic value of SUVmax in breast cancer. Purpose To determine if the SUVmax of a tumor on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) is associated with disease-free survival in patients with primary invasive ductal breast cancer. Material and Methods The institutional review board of our hospital approved this retrospective study. From 2009 to 2011, 508 women (mean age, 53.6 years; age range, 26–85 years) with newly diagnosed invasive ductal breast cancer who had undergone preoperative 18F-FDG PET/CT followed by surgery were identified. Clinicopathological variables and FDG uptake quantified by SUVmax were analyzed. The Cox proportional hazards model was used to evaluate the association between SUVmax and disease-free survival after controlling for clinicopathological parameters. Results There were 21 recurrences at a median follow-up of 46 months. The mean SUVmax of the primary tumor was significantly higher in patients with a recurrence than those who remained disease-free (9.5 ± 3.5 vs. 6.6 ± 4.2, P < 0.001). A receiver operating characteristic curve indicated that a SUVmax of 5.95 was the optimal cut-off value to predict disease-free survival. Multivariate analysis identified a high SUVmax (≥5.95) and high T stage as independent significant variables associated with worse disease-free survival. Conclusion A high primary tumor SUVmax on 18F-FDG PET/CT was an independent factor associated with worse disease-free survival in patients with primary invasive ductal breast cancer.

Magnetic resonance imaging characteristics of invasive breast cancer in women aged less than 35 years

Background With regard to clinicopathological findings and disease prognosis, breast cancer in young women is different from that in older women. However, few studies have investigated magnetic resonance imaging (MRI) characteristics of young age-onset breast cancer. Purpose To retrospectively evaluate and compare the MR images and clinicopathological characteristics of invasive breast cancer in young women (aged <35 years) with those of breast cancers in older premenopausal women (35–45 years). Material and Methods A total of 270 invasive breast cancers in 266 premenopausal women aged 45 years and younger who underwent preoperative breast MRI and curative surgery were identified between 2009 and 2013. The subjects were divided into a young group (<35 years, n = 56) and an older group (35–45 years, n = 214). MRI features and clinicopathological data were compared between the two groups. Results The young group had more positive axillary lymph nodes, higher histologic grade, negative estrogen receptor (ER), negative progesterone receptor (PR), and higher p53 and Ki-67 expression compared to the older group. Using MRI, the young group was more likely to display a round/oval or lobular mass shape, a smooth mass margin, and a high signal intensity on T2-weighted images when compared to the older group. In multivariate analysis, positive axillary nodal status (adjusted odds ratio [OR], 4.070; P = 0.002), higher expression of p53 (adjusted OR, 2.902; P = 0.038), lobular mass shape (adjusted OR, 4.979; P = 0.028), and smooth mass margin (adjusted OR, 5.123; P = 0.048) were independently associated with the young group. Conclusion MR morphologic features, including lobular mass shape and smooth mass margin, were independently associated with breast cancer in young women, in addition to positive axillary nodal status and higher p53 expression status.

AlF-4 and vanadate stimulate chloride secretion in rabbit colon by a Ca2+-dependent mechanism

Stripped rabbit descending colon mucosae were studied in vitro in modified Ussing chambers to determine the effects of AlF4−and vanadate on Cl− transport. Serosal additions of AlF4−and vanadate increase short-circuit current (ISC) and tissue conductance, while luminal addition of the agents is ineffective. Addition of aluminium potentiates the effect of NaF on ISC. AlF4−and vanadate increase serosal-to-mucosal flux of 36Cl without affecting mucosal-to-serosal flux. The effects of these agents on ISC are markedly inhibited by serosal addition of bumetanide and depend on the presence of Na+ in the serosal bathing solution. The effects of AlF4−and vanadate on ISC are dependent on the presence of Ca2+ in the bathing solution, and are completely inhibited by indomethacin, but the effect of forskolin is not affected by the removal of Ca2+ from the bathing solution and the addition of indomethacin. AlF4−and vanadate significantly increase the level of inositol phosphate metabolites. The results indicate that AlF4−and vanadate increase Cl− secretion in the rabbit colon via an increase in prostaglandin synthesis which is mediated by the increase of intracellular Ca2+ concentrations.

Shear Behavior of Reinforced Concrete Beams Strengthened by Epoxy Mortar Panel with Steel Fibers

The purpose of this study was to develop a new strengthening material that increases the shear strength and improves the deformation capacity of reinforced concrete (RC) beam members. A new composite material named epoxy mortar with steel fiber (EMSF) was prepared by inserting steel fibers into an epoxy mortar to provide the new strengthening material with high strength-toughness characteristics. In this study, materials and structural tests were employed. The materials tests assessed the influence of the volume percentage and the length of steel fiber on the tensile strength and toughness capacity of the composite material, EMSF. The structural tests help determine the influence of the EMSF panel type and thickness on the shear capacity and shear failure mode of strengthened RC beam members. The results of the two test groups are summarized as follows: 1) the results from the material tests indicated that the EMSF panel with 35 mm steel fibers exhibited high tensile strength, and the EMSF panel with both 35 mm and 50 mm steel fibers showed good toughness capacity; 2) the RC beam strengthened by an EMSF panel with short (35 mm) fibers possessed the highest shear strength, 3) the RC beam strengthened by an EMSF panel with both short (35 mm) and long (50 mm) fibers exhibited improved deformation capacity; and 4) a shear strength equation was derived from the equilibrium of the cracked RC beam members and is in good agreement with the test results.

Synthesis of Alumina Powders from Kaolin with and Without Ultrasounds

Alumina (Al2O3) powders were synthesized by extracting Al2O3 from kaolin via kaolin-H2SO4 reactions with and without ultrasounds. The amount of Al2O3 extracted from kaolin via the ultrasonic extraction process was investigated by comparing reaction time and reaction temperature with the same factors under the conventional extraction process. The time to obtaining a given amount of Al2O3 by the ultrasonic process was shorter than that by the conventional process, indicating that the application of ultrasound in the synthesis of Al2O3 powders is an efficient way to reduce synthesizing time.