Flow-Driven Self-Propulsion of Oil Droplet on a Surfactant Solution Surface, as Observed by Time-Resolved Interfacial Tension and Surface Flow Speed Measurements.

The imbalanced force of the interfacial tension applied to an object has often been taken into account in the analysis of the motion mechanism of self-propelled systems. However, heterogeneous distributions of the interfacial tension also cause Marangoni flows, and these flows also contribute to the self-propulsion through the viscous force. The contribution of such flows has not been observed directly, while the interfacial tension difference has been measured in some systems. In this study, simultaneous measurements of the interfacial tension and surface flow speed of the unidirectional self-propelled motion of a butyl salicylate (BS) droplet in a circular channel on a sodium dodecyl sulfate (SDS) aqueous solution were achieved by the quasi-elastic laser scattering method. The droplet position was also recorded by observing its fluorescence excited by a UV light. The BS droplet speed dependence of the interfacial tension and surface flow speed were measured by varying the initial BS concentration codissolved in the SDS aqueous solution. As a result, a periodic decrease of the interfacial tension and a periodic increase of the speed of both forward and backward flows were observed when the droplet passed the sampling position of the time-resolved measurements. When they were converted to the distribution in space of the droplet position, no droplet speed dependence of the interfacial tension difference between the front and rear of the droplet was observed. On the other hand, the speed of both forward and backward flows increased as the droplet speed increased. By analysis of the above results with a simplified model, it was clarified that the forward flow driven by the interfacial tension gradient at the droplet front is actually important in the mechanism of the unidirectional self-propelled motion of a droplet.

Subclassification of patients with intermediate-stage (Barcelona Clinic Liver Cancer stage-B) hepatocellular carcinoma using the up-to-seven criteria and serum tumor markers.

BACKGROUND: Intermediate-stage [Barcelona Clinic Liver Cancer stage-B (BCLC-B)] hepatocellular carcinoma (HCC) comprises of a heterogeneous population of patients with a wide range of tumor burdens. We therefore formulated a subclassification of BCLC-B HCC using the up-to-seven criteria and tumor markers according to the results of a retrospective analysis of these patients. METHODS: This study included 125 patients newly diagnosed with BCLC-B HCC who underwent transarterial chemoembolization. Among them, 39 and 86 were within or beyond the up-to-seven criteria, respectively. Multivariate Cox proportional hazards analysis was performed to investigate factors that contributed to better prognosis associated with the criteria. RESULTS: Cumulative overall survival (OS) and disease-free survival rates were significantly higher for patients within the up-to-seven criteria compared with those beyond (p = 0.034 and p = 0.001, respectively). Multivariate analysis revealed that low concentrations of des-γ-carboxy prothrombin (DCP) (<150 mAU/ml) and α-fetoprotein (AFP) (<100 ng/ml) were independent contributors to better OS of patients within or beyond the up-to-seven criteria, respectively. Accordingly, the patients were classified as follows: group A (patients within the up-to-seven criteria with DCP <150 mAU/ml), group C (patients beyond the up-to-seven criteria with AFP ≥100 ng/ml), and group B (other patients). OS differed significantly among groups (p < 0.001), and the median survival times of group A, B, and C were 4.2, 2.7, and 1.5 years, respectively. CONCLUSION: The subclassification system incorporating the up-to-seven criteria combined with DCP and AFP levels may serve as better predictors of prognosis that may guide efforts to improve treatment strategies.

Quick and stable parallel puncture of hepatic tumors using a double-barreled needle direction system for ultrasound-guided bipolar radiofrequency ablation.

AIM: In bipolar radiofrequency ablation (RFA) therapy, insertion of multiple needles at appropriate points on a target is difficult. The aim of our study was to evaluate a simplified method for multi-electrode insertion using a newly developed double-barreled needle guidance system for percutaneous RFA of hepatic tumors. METHODS: RFA using two bipolar electrodes was performed in 15 consecutive patients (nine men, six women; mean age, 72.0 ± 8.2 years) with a solitary small (≤3 cm) hepatic tumor. The first five nodules were treated using the conventional puncture method with the standard attachment, then 10 nodules were ablated using the parallel puncture method with the double-barreled attachment. The times required for double-needle placement and the shapes of the ablated areas were compared between the two puncture methods. RESULTS: The parallel puncture method required a shorter time for double-needle placement than the conventional method (12 s [range, 8-24] vs 96 s [range, 50-240]; P = 0.0003), and allowed continuous observation of the tip of all needles and the size of the ablated area as it increased until completion of the ablation. The method also provided a stable ellipsoidal ablated area. The median height, width and thickness were 30 mm (range, 22-34), 30 mm (range, 21-33) and 20 mm (range, 7-25), respectively, using 20-mm electrodes, and 34 mm (range, 32-41), 36 mm (range, 35-38) and 24 mm (range, 23-24), respectively, using 30-mm electrodes. CONCLUSION: The parallel puncture method may be a feasible procedure for multi-needle RFA therapy.

Three-dimensional registration of images obtained before and after radiofrequency ablation of hepatocellular carcinoma to assess treatment adequacy.

OBJECTIVE: The aim of our study was to evaluate the value of 3D registration images reconstructed by fusion of pre- and posttreatment CT or MRI for the assessment of ablative margins after percutaneous radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: From January 2007 to May 2011, we performed RFA in 84 patients to treat 139 HCC nodules, the margins of which had been assessed by comparing pre- and postablation images side by side. The same nodules were retrospectively assessed again with 3D registration images after classification into four margin grades. We analyzed the cumulative local recurrence rate for each grade and reviewed the origin of recurrence. RESULTS: Three-dimensional registration images predicted local recurrences more accurately than did the conventional side-by-side method (area under the curve, 0.678 and 0.536, respectively; p = 0.0144). The cumulative rates of local recurrence were significantly different among the margin grades assessed with 3D registration images (p = 0.0088). Three-dimensional registration images detected that the major origins of recurrence (n = 22) were residuals (n = 13) and sites of no margin (n = 6), especially proximate to blood vessels more than 3 mm in diameter. CONCLUSION: Three-dimensional registration of pre- and postablation CT or MRI more accurately assesses the ablative margin than the conventional method. It can predict a proclivity for local recurrence after RFA according to margin grade. It also indicated that residuals and sites of no margin proximate to blood vessels that are more than 3 mm in diameter are high-risk locations for local recurrence after ablation.

Computed tomography during hepatic arteriography pattern may predict hepatocellular carcinoma recurrence following transarterial chemoembolization.

AIM: This study aimed to determine the role of morphological patterns seen on imaging in predicting hepatocellular carcinoma recurrence following transarterial chemoembolization therapy. METHODS: Forty-seven patients from a single center who underwent transarterial chemoembolization to treat unresectable hepatocellular carcinomas between January 2011 and June 2012 were included in this study. We investigated whether the two pretreatment findings on computed tomography during hepatic arteriography (pattern 1, the single nodule pattern; pattern 2, at least one nodule showing the contiguous multinodular pattern) and other factors (age, sex, etiology, serum total bilirubin, serum albumin, prothrombin time, platelet count, serum level of protein induced by vitamin K absence/antagonist-II, serum α-fetoprotein, number of previous treatments for hepatocellular carcinoma, tumor number and maximum tumor size, presence of hypovascular lesions) could predict post-treatment recurrence. RESULTS: In a univariate analysis using Cox's proportional hazards model, serum total bilirubin, the serum level of protein induced by vitamin K absence/antagonist-II (≤100 vs ≥101 mAU/mL), tumor morphology (pattern 1 vs 2) and tumor number (≤3 vs ≥4) showed statistical significance (≤0.05). In a multivariate analysis of these factors, morphology and tumor number showed significance. According to Kaplan-Meier estimation, the cumulative disease-free survival rates were significantly lower in patients with four or more lesions than in those with three or less lesions and in patients showing pattern 2 than in those showing pattern 1. CONCLUSION: Patients with pattern 2 hepatocellular carcinoma and/or four or more lesions may have a relatively high recurrence rate after transarterial chemoembolization.

[Acute tumor lysis syndrome in the setting of advanced gastric cancer].

A 69-year-old man was admitted with right flank pain. The patient was diagnosed with advanced gastric cancer with multiple metastases in the liver and abdominal lymph nodes and underwent chemotherapy. Three days following the initial administration of S-1 plus cisplatin, the patient developed tumor lysis syndrome (TLS) with increased LDH, hyperuricemia, hyperkalemia, and elevated creatinine. Although rare, TLS following chemotherapy for solid tumors is a potentially fatal complication, and high physician awareness is required, especially in patients with risk factors, such as bulky disease.

[Mass-forming autoimmune pancreatitis caused after resection of an IgG4-related renal pelvic lesion].

A 64-year-old man was found to have a 15-mm tumor in the pancreatic tail by CT angiography 1 year after resection of a left renal pelvic tumor. Clinically, the tumor was preoperatively suspected to be autoimmune pancreatitis. However, surgical resection was performed under a diagnosis of pancreatic ductal cancer, because atypical epithelial cells were detected by endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA). Pathological examination of the tumor revealed a mass-forming autoimmune pancreatitis. Mass-forming autoimmune pancreatitis is often difficult to preoperatively differentiate from pancreatic carcinoma. Response to steroid treatment and the detection of extrapancreatic lesions may contribute to an accurate diagnosis, thereby avoiding unnecessary surgery.