Bacteriological and epidemiological characteristics of enterotoxigenic Escherichia coli isolated in Tokyo, Japan, between 1966 and 2009

Enterotoxigenic Escherichia coli (ETEC) caused 131 outbreaks in Tokyo, Japan, between 1966 and 2009. The major serogroups were O6, O27, O148, and O159. The incidence of serogroups O25 and O169 recently increased. Heat-stable enterotoxin (ST) subtyping revealed that E. coli of serogroups O6, O15, O25, and O159 possessed the STh gene, whereas those serotyped as O27 and O169 possessed the STp gene.     

Intrahepatic micrometastases around liver metastases from gastric cancer

Background/Purpose  We aimed to clarify the association between the presence of micrometastases around liver metastases from gastric cancer and the results of hepatic resection. In addition, we investigated the influence of E-cadherin and matrix metalloproteinase (MMP)-7 expression on the development of micrometastases. Methods  Micrometastases around liver metastases were examined microscopically in 31 metastatic liver tumor specimens resected from 17 patients who had undergone hepatic resection for liver metastases from gastric cancer. E-cadherin and MMP-7 expression in the primary gastric tumor, the liver metastases, and the micrometastases were examined immunohistochemically. Results  Hepatic micrometastases were present in around 48% of the liver metastases, accounting for 59% of the patients. The tumor recurrence rate in the remnant liver after hepatic resection was significantly higher, and survival significantly poorer, in patients with such micrometastases than in those without. Micrometastases tended to appear around the liver metastases that had reduced E-cadherin expression. Most of the micrometastases in the lymph ducts and sinusoids showed reduced E-cadherin expression. MMP-7 expression was not correlated with the presence of micrometastases. Conclusions  About half of the hepatic metastases from gastric cancer had seeded off micrometastases, and the presence of these micrometastases was associated with a poorer result of hepatic resection. Reduced E-cadherin expression in metastatic liver tumors may be associated with the development of micrometastases.     

Human hypertrophic nonunion tissue contains mesenchymal progenitor cells with multilineage capacity in vitro

Hypertrophic nonunion usually results from insufficient fracture stabilization. Therefore, most hypertrophic nonunions simply require the stabilization of the nonunion site. However, the reasons why union occurs without treating the nonunion site directly is not well understood biologically. In this study, we hypothesized that the intervening tissue at the hypertrophic nonunion site (nonunion tissue) could serve as a reservoir of mesenchymal progenitor cells and investigated whether the cells derived from nonunion tissue had the capacity for multilineage mesenchymal differentiation. After nonunion tissue was obtained, it was cut into strips and cultured. Homogenous fibroblastic adherent cells were obtained. Flow cytometry revealed that the adherent cells were consistently positive for mesenchymal stem cell related markers CD13, CD29, CD44, CD90, CD105, CD166, and negative for the hematopoietic markers CD14, CD34, CD45, and CD133, similar to control bone marrow stromal cells. In the presence of lineage‐specific induction factors, the adherent cells differentiated in vitro into osteogenic, chondrogenic, and adipogenic cells. These results demonstrated for the first time that hypertrophic nonunion tissue contains multilineage mesenchymal progenitor cells. This suggests that hypertrophic nonunion tissue plays an important role during the healing process of hypertrophic nonunion by serving as a reservoir of mesenchymal cells that are capable of transforming into cartilage and bone forming cells. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:208–215, 2009     

Brainstem atrophy on routine MR study in pallidopontonigral degeneration

Journal of Neurology -     

Histogenesis of metaplastic breast carcinoma and axillary nodal metastases

A 40-year-old breast-feeding woman presented with left breast swelling. On physical examination a 7 cm mass was found in the breast. Because biopsy demonstrated malignant tissue, mastectomy with axillary nodal dissection was performed. Pathological findings were consistent with metaplastic breast carcinoma with nodal metastases. The primary tumor consisted of three types of invasion: ductal, squamous, and sarcomatous. Furthermore, three morphological transitions were observed: ductal–squamous, ductal–sarcomatous, and squamous–sarcomatous. Ductal–squamous (12/18 microscopy slides) and squamous–sarcomatous transitions (10/18) were more commonly observed than ductal–sarcomatous transition (3/18). Furthermore, immunohistochemistry showed loss of epithelial marker (cytokeratin) and acquisition of mesenchymal markers (vimentin and α-smooth muscle actin) in the sarcomatous component. These findings suggested that epithelial–mesenchymal transition had occurred in the tumor and that two pathways, ductal–squamous–sarcomatous and ductal–sarcomatous transition, were involved in progression of metaplastic breast carcinoma. The main pathway appeared to be ductal–squamous–sarcomatous transition. Regarding the nodal metastases, of 13 positive nodes, ductal, squamous, and sarcomatous components were observed in 13, seven, and two nodes, respectively. Moreover, as in the primary tumor, ductal–squamous and squamous–sarcomatous transitions were observed. This suggested that the ductal component metastasized to the nodes and that epithelial–mesenchymal transition subsequently occurred within the nodes.     

Estimation of changes in dynamic hydraulic force in a magnetically suspended centrifugal blood pump with transient computational fluid dynamics analysis

The effect of the hydraulic force on magnetically levitated (maglev) pumps should be studied carefully to improve the suspension performance and the reliability of the pumps. A maglev centrifugal pump, developed at Ibaraki University, was modeled with 926 376 hexahedral elements for computational fluid dynamics (CFD) analyses. The pump has a fully open six-vane impeller with a diameter of 72.5 mm. A self-bearing motor suspends the impeller in the radial direction. The maximum pressure head and flow rate were 250 mmHg and 14 l/min, respectively. First, a steady-state analysis was performed using commercial code STAR-CD to confirm the model’s suitability by comparing the results with the real pump performance. Second, transient analysis was performed to estimate the hydraulic force on the levitated impeller. The impeller was rotated in steps of 1° using a sliding mesh. The force around the impeller was integrated at every step. The transient analysis revealed that the direction of the radial force changed dynamically as the vane’s position changed relative to the outlet port during one circulation, and the magnitude of this force was about 1 N. The current maglev pump has sufficient performance to counteract this hydraulic force. Transient CFD analysis is not only useful for observing dynamic flow conditions in a centrifugal pump but is also effective for obtaining information about the levitation dynamics of a maglev pump.     

In vitro short-term platelet adhesion on various metals

The in vitro short-term platelet adhesion on various metals, as accelerated by the addition of Ca²⁺, was evaluated in this study. Metals used for medical devices [an austenitic stainless steel, a cobalt (Co)-chromium (Cr)-molybdenum (Mo) alloy, a titanium (Ti)-6 aluminum (Al)-4 vanadium (V) alloy, a Ti-6Al-7 niobium (Nb) alloy, a Tinickel (Ni) alloy, and commercially pure Ti] were immersed into a platelet-rich plasma solution for 5 or 20 min, and platelet adhesion and aggregation on the surfaces were observed using a scanning electron microscope. The platelet adhesion level on each metal after 5 min of immersion in a platelet-rich plasma solution was the smallest in this order: stainless steel ≤ Co-Cr-Mo alloy < Ti-6Al-4V alloy < Ti-6Al-7Nb alloy < Ti-Ni alloy = Ti. The levels after 5 min of immersion were almost the same as those after 20 min of immersion. Platelet adhesion was minimal on stainless steel and Co-Cr-Mo alloy, which have a Cr₂O₃-containing passive surface oxide film, but was accelerated on Ti and Ti alloys having a TiO₂-contanining film. A Cr₂O₃-containing oxide film has a lower relative permittivity than a TiO₂-contanining film; it thus supports a larger electrostatic force than the latter, adsorbs more albumins, which work as inhibitory proteins, and inhibits platelet aggregation. Therefore, platelet adhesion and aggregation are controlled by the composition of the surface oxide film on a metal due to the relative permittivity of the metal, which influences the amount of adsorbed proteins.     

The use of Blake drains following general thoracic surgery: is it an acceptable option?

As a method of chest drainage, we analyzed the extended utility of silastic flexible drains (Blake drains, Ethicon, Inc., Somerville, NJ) for general thoracic surgery. In 420 cases of general thoracic surgery, Blake drains were used. To examine the utility of Blake drains, we investigated the diseases for which they were used, their effectiveness in addressing postoperative complications. The treated diseases for which Blake drains were used comprised 181 cases of primary lung cancer, 44 cases of metastatic lung tumor, 57 cases of benign lung disease, 32 cases of mediastinal tumor, 6 cases of myasthenia gravis, 76 cases of spontaneous pneumothorax, 14 cases of chest wall and/or pleural tumor, 6 cases of empyema, and 4 cases of diaphragmatic disease. Blake drains functioned efficiently in 3 cases of re-operation for postoperative bleeding, 2 cases of adhesion therapy with drugs for persistent air leaks, and 1 case of re-operation for chylothorax. There were no cases of either complications or patient complaints of discomfort resulting from drain placement. The use of Blake drains for general thoracic surgery is considered to be an acceptable option, and it is necessary to proceed with further investigations of larger numbers of cases.