Deformation Behavior of Body-Centered Cubic Lattice in Polymers.

A body-centered cubic (BCC) lattice is a crystal unit cell structure observed in metals, inorganics, and polymers. The deformation behavior of the BCC lattice in metals has been well elucidated, whereas that of polymers remains unclear. We used a microphase-separated copolymer with randomly oriented grains wherein spherical phases are packed in the BCC lattice. The copolymer showed affine deformation under a strain of 1.8, which is much larger than that observed for metals, followed by spectacular rearrangement and "push-and-shove" deformation. To the best of our knowledge, these structural changes have not yet been observed in metals. These differences in the behavior of metals and polymers arise depending on the contact state of the spherical phases.

Preparation and characterization of an imogolite/chitosan hybrid with pyridoxal-5'-phosphate as an interfacial modifier.

Imogolite/chitosan hybrid films were prepared using pyridoxal-5'-phosphate (PLP) as an interfacial modifier. Thermogravimetric analysis and spectroscopic measurements revealed that the phosphate group of PLP was adsorbed on the imogolite. Furthermore, rheological measurements suggested that the PLP-modified imogolites (PLP-imogolite) had strong interactions with chitosan in solution. Moreover, UV absorption of the hybrid film showed that PLP and chitosan formed Schiff base linkages. Therefore, the hybrid films exhibited a significant improvement in their mechanical properties compared to those of pristine chitosan/imogolite hybrid films.

Depth-Resolved Characterization of Perylenediimide Side-Chain Polymer Thin Film Structure Using Grazing-Incidence Wide-Angle X-ray Diffraction with Tender X-rays.

Polymers with a perylenediimide (PDI) side chain (PAc12PDI) consist of two kinds of crystalline structures with various types of orientations in a thin film. Understanding the population of the microcrystalline structure and its orientation along the thickness is strongly desired. Grazing-incidence wide-angle X-ray diffraction (GIWAXD) measurements with hard X-rays, which are generally chosen as λ = 0.1 nm, are a powerful tool to evaluate the molecular aggregation structure in thin films. A depth-resolved analysis for the outermost surface of the polymeric materials using conventional GIWAXD measurements, however, has limitations on depth resolution because the X-ray penetration depth dramatically increases above the critical angle. Meanwhile, tender X-rays (λ = 0.5 nm) have the potential advantage that the penetration depth gradually increases above the critical angle, leading to precise characterization for the population of crystallite distribution along the thickness. The population of the microcrystalline states in the PAc12PDI thin film was precisely characterized utilizing GIWAXD measurements using tender X-rays. The outermost surface of the PAc12PDI thin film is occupied by a monoclinic lattice with a = 2.38 nm, b = 0.74 nm, c = 5.98 nm, and ß = 108.13°, while maintaining the c-axis perpendicular to the substrate surface. Additionally, the presence of solid substrate controls the formation of the crystallite with unidirectional orientation.

Radiofrequency ablation for colorectal liver metastases: prognostic factors in non-surgical candidates.

PURPOSE: To determine prognostic factors in patients with colorectal liver metastases who were not surgical candidates and received liver radiofrequency (RF) ablation. MATERIALS AND METHODS: RF ablation was done for 141 colorectal liver metastases in 84 patients. There were 63 (75.0 %, 63/84) males and 21 (25.0 %, 21/84) females, with a mean age of 64.6 ± 10.3. The mean maximum tumor diameter was 2.3 ± 1.4 cm (range 0.5-9.0 cm). Extrahepatic metastases were associated at the time of liver RF ablation in 23 patients (27.4 %, 23/84), and 12 (14.3 %, 12/84) had lung metastases considered controllable by planned lung RF ablation. Prognostic factors were evaluated by univariate and multivariate analyses. RESULTS: There was no procedure-related mortality. The 1-, 3-, and 5-year overall survival rates were 90.6 % (95 %CI, 83.9-97.2 %), 44.9 % (95 %CI, 31.8-57.9 %), and 20.8 % (95 %CI, 7.3-34.3 %), respectively, with a median survival of 34.9 months. The univariate analysis showed that tumor diameter larger than 3 cm, tumor multiplicity, uncontrollable extrahepatic disease, and previous chemotherapy history were significantly worse prognostic factors. The former three factors remained significant for worse prognosis in the multivariate Cox model. Extrahepatic disease was not a prognostic factor when it could be controlled. CONCLUSION: Tumor size and number, and uncontrollable extrahepatic metastases were significant prognostic factors.

Clinical utility of coaxial reservoir system for hepatic arterial infusion chemotherapy.

PURPOSE: To test the feasibility and clinical utility of a reservoir with coaxial catheters (a 2.9-F microcatheter and a 5-F catheter) and a port (ie, coaxial reservoir) that was developed to perform repeated hepatic arterial infusion chemotherapy (HAIC) in patients with unresectable liver neoplasms. MATERIALS AND METHODS: The coaxial reservoir was implanted in 64 patients with unresectable liver neoplasms as a result of difficulty in implanting a conventional reservoir with a 5-F catheter. The 2.9-F microcatheter tip was inserted into the gastroduodenal artery (n = 22), pancreaticoduodenal arcade (n = 20), or peripheral hepatic artery (n = 22) through the 5-F catheter, and a side hole created in the leading end of the microcatheter was oriented toward the proper hepatic artery. Technical success was defined by implantation of the coaxial reservoir and initiation of HAIC. The study endpoint was interruption of HAIC or death. Technical success and early and delayed complications were recorded. RESULTS: The technical success rate was 100%. HAIC was repeated every 1-4 weeks during the mean follow-up period of 14.1 months. Arterial infusion chemotherapy was interrupted in 17 patients (27%) as a result of hepatic arterial occlusion (16%, n = 10), catheter dislocation (3%, n = 2), catheter occlusion (3%, n = 2), wound infection (3%, n = 2), or breakage of the port (2%, n = 1). Patency rates of the hepatic artery were 96%, 82%, and 50% at 6 months, 1 year, and 2 years after reservoir implantation, respectively. CONCLUSION: Implantation of the coaxial reservoir is feasible, safe, and useful in expanding the indication of HAIC to patients with unresectable liver neoplasms.

Long-term optional retrievability of a new inferior vena cava filter in an ovine model.

Long-term retrievability of a new optional retrieval inferior vena cava (IVC) filter composed of a modified square stent and a modified Günther Tulip filter was tested in eight sheep. Eleven filters were placed into the IVC and eight were successfully retrieved 3-5 months after implantation. Incorporation of the filter struts into the IVC wall prevented its retrieval in three sheep at 3, 4, and 5 months after placement.

Significance of spatial orientation of percutaneously placed bioprosthetic venous valves in an ovine model.

PURPOSE: To investigate two spatial orientations of a percutaneously placed bicuspid second-generation bioprosthetic venous valve (SG-BVV) in the jugular vein (JV). MATERIALS AND METHODS: Twelve SG-BVVs, consisting of small intestinal submucosa attached to a nitinol frame were placed across a natural valve (NV) in the distal JV in six sheep. Six SG-BVVs were oriented as NV leaflets (group A) and the other six SG-BVVs were rotated 90 degrees to NV leaflets (group B). SG-BVV function was studied by venography performed immediately after placement and at 5 weeks after placement. Animals were killed at 5 weeks, and gross examinations were performed. RESULTS: Desired valve orientation after deployment was seen in all SG-BVVs. In group A, all valves exhibited good valve function on immediate and 5-week venography. At gross examination, leaflets were attached mostly at the valve base and free cusp areas were similar in both cusps with a mean of 154.8 mm2 +/- 45.6 for one cusp and 142 mm2 +/- 53.4 for the other cusp (P = .188). In group B, all valves showed good function on immediate venography and in five valves prior to killing. Valve attachment to the vein wall in this group involved a longer segment of leaflets and their free areas were smaller with a wide variety of cusp sizes. Mean free leaflet areas of opposing cusps measured 106.3 mm2 +/- 36.5 and 66.1 mm2 +/- 34.6, respectively (P = .025). Difference in leaflet areas between group A and group B was significant (P = .019). CONCLUSION: Proper spatial orientation of the SG-BVV at deployment is important for valve function and should have the same orientation as the NV.

Hepatic arterial infusion chemotherapy with use of an implanted port system in patients with advanced hepatocellular carcinoma: prognostic factors.

PURPOSE: This study was retrospectively undertaken to identify prognostic factors in patients with advanced hepatocellular carcinoma (HCC) treated by hepatic arterial infusion chemotherapy with a percutaneously implantable port system inserted. MATERIALS AND METHODS: Eighty-eight patients underwent arterial infusion chemotherapy for portal venous invasion (n = 39), severe liver dysfunction (n = 6), or tumor regrowth after chemoembolization, percutaneous ethanol injection therapy, and surgery (n = 77). Twenty-five variables representing patients' characteristics, previous treatments, tumor characteristics, liver profiles, various staging systems, and therapeutic effect were analyzed with univariate and multivariate analyses. RESULTS: The 1- and 3-year survival rates were 55% and 24%, respectively, with a mean survival period of 19.5 months +/- 1.9 in all patients. Cancer of the Liver Italian Program (CLIP) score, Okuda stage, therapeutic effect, tumor extension, alkaline phosphatase and aspartate aminotransferase levels, ascites, and portal venous invasion were identified as significant prognostic factors by univariate analysis. Multivariate analysis identified CLIP score, Okuda stage, and therapeutic effect as significant independent prognostic factors. CONCLUSION: Although our results should be confirmed in future prospective studies, the prognostic factors identified in the present study should prove helpful in classifying patients with advanced HCC who are treated by arterial infusion chemotherapy and should serve as useful guidelines on arterial infusion chemotherapy in clinical practice.

Radiofrequency ablation combined with bone cement injection for the treatment of bone malignancies.

PURPOSE: To evaluate the feasibility, safety, and effectiveness of combined treatment with radiofrequency (RF) ablation followed by bone cement injection in patients with malignant bone neoplasms. MATERIALS AND METHODS: Seventeen patients with 23 bone tumors were treated. The tumors, measuring 1.2-15 cm (mean, 4.9 +/- 3.5 cm), were located in the spine (n = 17), iliac bone (n = 3), sacrum (n = 2), and ischial bone (n = 1). All procedures were performed with computed tomographic (CT) fluoroscopic guidance. An electrode with an internally cooled tip was placed in the bone tumor through a biopsy needle and RF energy was applied, followed by cement injection. Pain relief was evaluated with use of the visual analogue scale score (VAS score). Local therapeutic effects were evaluated by contrast-enhanced MR imaging. Lack of tumor enhancement was considered to indicate necrosis. RESULTS: The procedures were technically successful in all patients except for one patient with an osteoblastic ischial lesion (22 of 23 patients; 96%). Pain was relieved within 1 week in all 13 patients who reported pain (13 of 13 patients; 100%), with a significant decrease in the VAS score from 8.4 to 1.1 (P <.001). Tumor necrosis was observed in 71% +/- 24% of the tumor volume (range, 14%-100%). Neural damage occurred in four patients in whom the tumor had invaded the posterior cortex of the vertebral body and pedicle. CONCLUSION: The combined therapy described here is both feasible and useful for the treatment of malignant bone neoplasms. The safety of the procedure depends on the tumor location. When the tumor is adjacent to the spinal cord, there is a risk of nerve injury.

Repeated hepatic arterial infusion chemotherapy using an implanted port system in patients with unresectable malignant liver neoplasms: significant factors affecting early hepatic arterial occlusion.

The purpose of this study was to identify significant factors affecting early hepatic arterial occlusion in patients who received repeated hepatic arterial infusion chemotherapy using an implanted port system. Eighty-five patients with unresectable liver neoplasms who underwent implantation of the port system were studied. Arterial infusion chemotherapy was performed every 1-4 weeks. Arterial occlusion was evaluated by hepatic arteriography performed via the port every 3 months. Twenty variables were analyzed using univariate and multivariate analyses to identify significant factors affecting early hepatic arterial occlusion. Hepatic arterial occlusion was found in 25.9% (22/85) of the patients. Thirteen of them experienced early arterial occlusion within 6 months. The mean survival period was significantly worse in patients who experienced early arterial occlusion than those who did not (16 months vs. 26 months, p<0.05). In the multivariate analysis, the following 3 variables had independent value for early arterial occlusion; i). diameter of the common hepatic artery, ii). gender, and iii). previous systemic chemotherapy. Early arterial occlusion affects therapeutic effects and survival in patients who undergo arterial infusion chemotherapy with an implanted port. Factors demonstrated here are important to classify patients at risk of early hepatic arterial occlusion.

[Clinical usefulness of reservoir system with a coaxial catheter].

We have developed a new implantable catheter and port system (reservoir) with a 2.9 Fr coaxial catheter. This study was undertaken to evaluate the initial results of the new reservoir system. Fifty-three patients with liver neoplasms underwent implantation of this reservoir owing to tortuousity, angulation, and stenosis of the hepatic arteries, and received repeated arterial infusion chemotherapy. Implantation was technically successful in all patients. Hepatic arterial occlusion occurred at rates of 13.7% at six months and 35.3% at one year. There were no major complications apart from port infection in two patients. This reservoir with a 2.9 Fr catheter expands the indications of hepatic arterial infusion chemotherapy.