Maintenance of Cartilaginous Gene Expression of Serially Subcultured Chondrocytes on Poly(2-Methoxyethyl Acrylate) Analogous Polymers.

Chondrocytes are important for cartilage tissue engineering. However, dedifferentiation during chondrocyte subculture prevents the application of cartilage tissue engineering. Therefore, prevention of this dedifferentiation is required. Here, the possibility of poly(2-methoxyethyl acrylate) (PMEA) and its analogous polymers, poly(tetrahydrofurfuryl acrylate) (PTHFA) and poly(2-(2-methoxyethoxy) ethyl acrylate-co-butyl acrylate) (PMe2A), for chondrocyte subculture without dedifferentiation is examined. Chondrocytes spread on PTHFA and polyethylene terephthalate (PET), whereas their spreading is delayed on PMEA and PMe2A. When primary chondrocytes are subcultured on these polymers, the expression levels of cartilaginous genes are higher on PMEA and PMe2A than on PET and PTHFA. Integrin contribution to the initial cell adhesion is lower on PMEA and PMe2A than on PTHFA and PET. This low level of integrin contribution to cell adhesion may cause a delay in cell spreading and the maintenance of cartilaginous gene expression. These results indicate that PMEA and PMe2A may be favorable substrates for chondrocyte subculture and cartilage tissue engineering.

Promotion of Adipogenesis of 3T3-L1 Cells on Protein Adsorption-Suppressing Poly(2-methoxyethyl acrylate) Analogs.

Stem cell differentiation is an important issue in regenerative medicine and tissue engineering. It has been reported that cell shape is one of the factors that determine the lineage commitment of mesenchymal stem cells (MSCs). Therefore, the substrates have been developed to control their shapes. Recently, we found that poly(2-methoxyethyl acrylate) (PMEA) analogs can control tumor cell shape through the alteration of protein adsorption. Here, the adipogenesis of an adipocyte-progenitor cell, 3T3-L1 cells, was attempted; adipogenesis was to be regulated by surfaces coated with PMEA analogs through the control of their shape. The adipogenesis of 3T3-L1 cells was promoted on the surfaces coated with PMEA and its analogs, PMe3A and PMe2A. Evident focal adhesions were hardly observed on these surfaces, suggesting that integrin signal activation was suppressed. Additionally, actin assembly and cell spreading were suppressed on these surfaces. Therefore, the surfaces coated with PMEA analogs are expected to be suitable surfaces to regulate adipogenesis through the suppression of cell spreading. Additionally, we found that protein adsorption correlated with actin assembly and adipogenesis.

Decellularized Extracellular Matrix as an In Vitro Model to Study the Comprehensive Roles of the ECM in Stem Cell Differentiation.

Stem cells are a promising cell source for regenerative medicine. Stem cell differentiation must be regulated for applications in regenerative medicine. Stem cells are surrounded by extracellular matrix (ECM) in vivo. The ECM is composed of many types of proteins and glycosaminoglycans that assemble into a complex structure. The assembly of ECM molecules influences stem cell differentiation through orchestrated intracellular signaling activated by many ECM molecules. Therefore, it is important to understand the comprehensive role of the ECM in stem cell differentiation as well as the functions of the individual ECM molecules. Decellularized ECM is a useful in vitro model for studying the comprehensive roles of ECM because it retains a native-like structure and composition. Decellularized ECM can be obtained from in vivo tissue ECM or ECM fabricated by cells cultured in vitro. It is important to select the correct decellularized ECM because each type has different properties. In this review, tissue-derived and cell-derived decellularized ECMs are compared as in vitro ECM models to examine the comprehensive roles of the ECM in stem cell differentiation. We also summarize recent studies using decellularized ECM to determine the comprehensive roles of the ECM in stem cell differentiation.

[A case of consciousness disorder induced by the syndrome of inappropriate secretion of antidiuretic hormone following cisplatin and 5-fluorouracil chemotherapy in a patient with esophageal cancer].

We report a case of consciousness disorder following the fourth course of chemotherapy with cisplatin (CDDP) and 5- fluorouracil (5-FU) in a patient with esophageal cancer. A 74-year-old man was admitted to our hospital to receive chemotherapy for esophageal cancer. Six days after chemotherapy, the patient showed impaired consciousness and his serum sodium concentration was found to be 125 mEq/L, but no edema or dehydration was noted. This hyponatremic state was diagnosed as CDDP-induced syndrome of inappropriate secretion of antidiuretic hormone (SIADH) on the basis of serum and urine hypo-osmolality. Accordingly, fluid intake was restricted and sodium supplements were administered, resulting in an appropriate increase in the serum sodium concentration to 132 mEq/L in 4 days.

[Pathological complete response in 2 patients with cT4 esophageal cancer treated with neoadjuvant chemoradiation therapy].

We report the cases of 2 patients with clinical T4( cT4) esophageal cancer who achieved pathological complete response on treatment with neoadjuvant chemoradiation therapy. Case 1 involved a 68-year-old woman who was diagnosed as having cT4 advanced esophageal cancer( with involvement of the aorta and left pulmonary vein). Neoadjuvant chemoradiation therapy with 5-fluorouraci(l 5-FU)( 800 mg/m2, days 1-5 and days 29-33), cisplatin( CDDP 80 mg/m2, days 1 and 29), and radiation (39.6 Gy/22 Fr) was administered, and the tumor showed a partial response (PR). Case 2 involved a 69-year-old man who was diagnosed as having cT4 advanced esophageal cancer( with involvement of the main bronchus). Neoadjuvant chemoradiation therapy with 5-FU( 800 mg/m2, days 1-5 and days 29-33), CDDP( 80 mg/m2, days 1 and 29), and radiation( 39.6 Gy/22 Fr) was administered, and the tumor showed a clinical PR. After tumor response was noted, curative esophagectomy was performed in both cases, without any complications, and a pathological complete response was achieved in both patients.

Extensive multidrug resistance of coagulase-negative staphylococci in medical students.

Staphylococcus aureus and coagulase-negative staphylococci (CNS) isolated from the nasal mucosa of medical students were examined for susceptibility to 16 antimicrobial agents. No methicillin-resistant S. aureus (MRSA) was isolated, while MRCNS was present in 23.5% of the medical students. CNS exhibited significantly more resistance to antimicrobial agents such as gentamicin, in addition to oxacillin, compared to S. aureus, and 13.1% of the CNS strains (mostly MRCNS) were multidrug-resistant (to five or more drugs). In contrast, ampicillin resistance was higher in S. aureus. The rate of hospitalization or of taking an antimicrobial agent within the past 1 year was lower in CNS+ students than in S. aureus+ students. The data suggest that CNS could serve as a reservoir of drug resistance by persistent colonization in the nasal mucosa. In this study, MRCNS with multidrug resistance was found in medical students. More attention should be given to nasal MRCNS in medical students as a possible spreader in hospitals.