Development of advanced skin dose evaluation technique using a tetrahedral-mesh phantom in external beam radiotherapy: a Monte Carlo simulation study.

Incorrect prediction of skin dose in external beam radiotherapy (EBR) can have normal tissue complication such as acute skin desquamation and skin necrosis. The absorbed dose of skin should be evaluated within basal layer, placed between the epidermis and dermis layers. However, current treatment planning systems (TPS) cannot correctly define the skin layer because of the limitation of voxel resolution in computed tomography (CT). Recently, a new tetrahedral-mesh (TM) phantom was developed to evaluate radiation dose realistically. This study aims to develop a technique to evaluate realistic skin dose using the TM phantom in EBR. The TM phantom was modeled with thin skin layers, including the epidermis, basal layer, and dermis from CT images. Using the Geant4 toolkit, the simulation was performed to evaluate the skin dose according to the radiation treatment conditions. The skin dose was evaluated at a surface depth of 50 µm and 2000 µm. The difference in average skin dose between depths was up to 37%, depending on the thickness and region of the skin to be measured. The results indicate that the skin dose has been overestimated when the skin is evaluated using commercial TPS. Although it is not possible with traditional TPS, our skin dose evaluation technique can realistically express the absorbed dose at thin skin layers from a patient-specific phantom.

Highly Angiogenic, Nonthrombogenic Bone Marrow Mononuclear Cell-Derived Spheroids in Intraportal Islet Transplantation.

Highly angiogenic bone marrow mononuclear cell-derived spheroids (BM-spheroids), formed by selective proliferation of the CD31+CD14+CD34+ monocyte subset via three-dimensional (3D) culture, have had robust angiogenetic capacity in rodent syngeneic renal subcapsular islet transplantation. We wondered whether the efficacy of BM-spheroids could be demonstrated in clinically relevant intraportal islet transplantation models without increasing the risk of portal thrombosis. The thrombogenic potential of intraportally infused BM-spheroids was compared with that of mesenchymal stem cells (MSCs) and MSC-derived spheroids (MSC-spheroids). The angiogenic efficacy and persistence in portal sinusoids of BM-spheroids were examined in rodent syngeneic and primate allogeneic intraportal islet transplantation models. In contrast to MSCs and MSC-spheroids, intraportal infusion of BM-spheroids did not evoke portal thrombosis. BM-spheroids had robust angiogenetic capacity in both the rodent and primate intraportal islet transplantation models and improved posttransplant glycemic outcomes. MRI and intravital microscopy findings revealed the persistence of intraportally infused BM-spheroids in portal sinusoids. Intraportal cotransplantation of allogeneic islets with autologous BM-spheroids in nonhuman primates further confirmed the clinical feasibility of this approach. In conclusion, cotransplantation of BM-spheroids enhances intraportal islet transplantation outcome without portal thrombosis in mice and nonhuman primates. Generating BM-spheroids by 3D culture prevented the rapid migration and disappearance of intraportally infused therapeutic cells.

Validation of energy-weighted algorithm for radiation portal monitor using plastic scintillator.

To prevent illicit tracking of radionuclides, radiation portal monitor (RPM) systems employing plastic scintillators have been used in ports and airports. However, their poor energy resolution makes the discrimination of radioactive material inaccurate. In this study, an energy weight algorithm was validated to determine (133)Ba, (22)Na, (137)Cs, and (60)Co by using a plastic scintillator. The Compton edges of energy spectra were converted to peaks based on the algorithm. The peaks have a maximum error of 6% towards the theoretical Compton edge.

The real-world application of single incision laparoscopic cholecystectomy.

OBJECTIVES: Most previous studies that have investigated single incision laparoscopic cholecystectomy (SILC) are case series with limited sample sizes. We have reviewed the outcome of 500 consecutive cases of SILC performed by a single surgeon at our center. MATERIALS AND METHODS: From April 2009 to October 2012, a single surgeon performed 1250 laparoscopic cholecystectomies for various gallbladder (GB) diseases. SILC was chosen as the surgical modality unless there was evidence of acute cholecystitis or GB empyema, the patient had a prior history of upper abdominal surgery, endoscopic sphincterotomy, or had comorbidities with an ASA score of III or higher. The clinicopathologic features and perioperative data of patients were retrospectively reviewed. RESULTS: The mean age and BMI of included patients were 42.7 years and 23.6 kg/m(2), respectively. The mean operating time was 52 min. Patients stayed in the hospital for an average of 1.3 days postoperatively. In 55 patients, an additional 2 mm trocar was inserted for retraction of the GB. One patient was converted to an open cholecystectomy because of Mirizzi syndrome. There were no observed complications including incisional hernias in this patient population. CONCLUSIONS: SILC is a safe, effective procedure for cholecystectomy that may be considered the main surgical strategy in select patients.

The analysis of mutations and exon deletions at TSC2 gene in angiomyolipomas associated with tuberous sclerosis complex.

Angiomyolipomas (AMLs) are relatively rare hamartomatous or benign tumors that occasionally occur as part of tuberous sclerosis complex (TSC). Mutations in either of the two genes, TSC1 and TSC2, have been attributed to the development of TSC. Between 1994 and January 2009, 83 patients were diagnosed with AML at the Samsung Medical Center. In that group of patients, 5 (6%) had AML with TSC (AML-TSC). Mutational analysis of the TSC2 gene was performed using 7 samples from the 5 AML-TSC patients and 14 samples from 14 patients with sporadic AML without TSC (AML-non-TSC). From this analysis, mutations in TSC genes were identified in 5 samples from the AML-TSC patients (mutation detection rate=71%) and 3 samples from AML-non-TSC patients (mutation detection rate=21%). In the case of AML-TSC, 6 mutations were found including 3 recurrent mutations and 3 novel mutations, while in the case of AML-non-TSC, 4 mutations were identified once, including 1 novel mutation. Also MLPA analysis of the TSC2 gene showed that TSC2 exon deletion is more frequently observed in AML-TSC patients than in AML-non-TSC patients. This is the first mutation and multiplex ligation-dependent probe amplification (MLPA) analyses of TSC2 in Korean AMLs that focus on TSC. This study provides data that are representative of the distribution of mutations and exon deletions at TSC genes in clinically diagnosed AML-TSC cases of the Korean population.

Role of radical antegrade modular pancreatosplenectomy for adenocarcinoma of the body and tail of the pancreas.

BACKGROUND: Studies have claimed that in the surgical treatment of pancreas body and tail cancer, radical antegrade modular pancreatosplenectomy (RAMPS) is associated with effective tangential margin and extensive lymph node dissection. In the present study, the authors have compared the surgical outcomes between RAMPS and conventional distal pancreatosplenectomy (DPS) in patients with adenocarcinoma of the pancreas body and tail, and also identified prognostic factors associated with survival after surgery. METHODS: Retrospective review of 92 consecutive patients who underwent surgical resection for pancreas body and tail adenocarcinoma with curative intent between 1995 and 2010. Median follow-up duration was 16.1 months. RESULTS: Of the 92 patients, 38 patients received RAMPS and 54 patients received DPS. Patients who underwent RAMPS had a greater number of retrieved lymph nodes than patients undergoing DPS [median 14 (5-52) vs. 9 (1-36), p < 0.05]. Conventional DPS, no adjuvant chemoradiation therapy (CRT), and non-curative resection were associated with poor overall survival (OS) on univariate analysis. After multivariate analysis for these variables, only the lack of adjuvant CRT and resection margin status were found to adversely affect OS. CONCLUSIONS: While the RAMPS procedure is effective in performing an extensive LN dissection, it is not associated with better retroperitoneal resection margin or retrieval of more positive LNs, and it does not lead to better curability or OS survival compared to DPS. Lack of adjuvant CRT and resection margin status are poor prognostic factors in patients with pancreas body and tail cancer.

Clinicopathologic analysis of undifferentiated carcinoma of the gallbladder.

BACKGROUND: Undifferentiated carcinoma (UC) of the gallbladder (GB) is a rare malignant neoplasm and there have only been sparse case reports without precise description. We analyzed eight cases of UC of GB and compared with gallbladder carcinoma (GBC) in the aspects of clinicopathologic characteristics and prognosis. METHODS: We found eight UC cases out of 238 surgically resected GBCs. Patients with stage-matched GBC were selected (1:4) for comparative analysis of the clinicopathologic features and survival of UC. RESULTS: Histologically, UC cases were composed of four sarcomatoid, two pleomorphic, one small cell, and one osteoclast-like giant cell types. There was no difference between UC and ordinary GBC in clinicopathologic parameters, except for tumor size. It was significantly larger in UC (median; 5.0 cm, ranging 1.3-10.0 cm) compared to GBC (median; 3.0 cm, ranging 1.5-9.0 cm, P = 0.01). UC presented frequent intraluminal polypoid mass (87.5%: 7/8). UC showed significantly poor overall survival rate (37.5%, 37.5% and 18.8% at 1, 3, and 5 years), than GBC (84.4%, 65.6% and 52.1%, respectively) (P = 0.005). Pathologic findings of UC were an independent prognostic factor for poor survival in GBC (HR 7.242, 95% confidence interval: 1.799-29.147). CONCLUSIONS: Undifferentiated carcinoma of the gallbladder was a rare highly malignant neoplasm and frequently presented a large intraluminal polypoid tumor. It showed a significantly larger tumor size and poorer survival than GBC.

Role of caudate lobectomy in type III A and III B hilar cholangiocarcinoma: a 15-year experience in a tertiary institution.

BACKGROUND: Concomitant liver resection for type III hilar cholangiocarcinoma could improve the R0 resection rate and long-term outcome. In the present study, we examine the specific role of caudate lobectomy in liver resection for type III(A) and III(B) hilar cholangiocarcinoma and the prognostic factors for survival in this group of patients. METHODS: We reviewed all patients with type III(A) and III(B) hilar cholangiocarcinoma who underwent liver resection in Samsung Medical Center from January 1995 to July 2010. Patients were divided into those with and without caudate lobectomy (CL). The log rank test and Cox regression analysis were employed to investigate for prognostic factors of survival. RESULTS: There were 127 patients in this cohort, 57 without CL (44.9%) and 70 with CL (55.1%). The demographics and symptoms of presentation were comparable. The median preoperative bilirubin level was significantly higher in the group undergoing CL (p = 0.017). Patients with CL had a significantly better overall survival (OS) (CL: 64.0 months vs without CL: 34.6 months) (p = 0.010) and disease-free survival (DFS) (CL: 40.5 months vs without CL: 27.0 months) (p = 0.031). Multivariate analysis showed that presence of symptoms (p = 0.025) and positive lymph node (LN) metastasis (p < 0.001) were negative prognostic factors for OS. Furthermore, multivariate analysis for DFS found that caudate lobectomy (p = 0.016) and positive LN metastasis (p = 0.001) were positive and negative prognostic factors, respectively. CONCLUSIONS: Caudate lobectomy contributed to improvement of DFS and OS in type III hilar cholangiocarcinoma. Other prognostic factors include positive LN metastasis and presence of symptoms.

Diminished expression of dihydropteridine reductase is a potent biomarker for hypertensive vessels.

To identify the new targets for hypertension, we analyzed the protein expression profiles of aortic smooth muscle in spontaneously hypertensive rats (SHR) of various ages during the development of hypertension, as well as in age-matched normotensive Wistar-Kyoto (WKY) rats, using a proteomic analysis. The expressions of seven proteins were altered in SHR compared with WKY rats. Of these proteins, NADH dehydrogenase 1alpha, GSTomega1, peroxi-redoxin I and transgelin were upregulated in SHR compared with WKY rats. On the other hand, the expression of HSP27 and Ran protein decreased in SHR. The diminution of dihydrobiopterin reductase, an enzyme located in the regeneration pathways of tetrahydrobiopterin (BH4), was also prominent in SHR. The results from a PCR analysis revealed that the expression of BH4 biosynthesis enzymes - GTP cyclohydrolase-1 and sepiapterin reductase - decreased and increased, respectively, in SHR compared with WKY rats. The level of BH4 was less in aortic strips from SHR than from WKY rats. Moreover, treatment with BH4 inhibited aortic smooth muscle contraction induced by serotonin. These results suggest that the deficiency in BH4 regeneration produced by diminished dihydrobiopterin reductase expression is involved in vascular disorders in hypertensive rats.

Beta-secretase (BACE1) inhibitors from Perilla frutescens var. acuta.

In the course of screening for anti-dementia agents from natural products, two beta-secretase (BACE1) inhibitors were isolated from the methanolic extract of Perilla frutescens var. acuta and identified as luteolin (1) and rosmarinic acid (2) with IC50 values of 5.0 x 10(-7) M and 2.1 x 10(-5) M, respectively. They inhibited BACE1 in a non-competitive manner with a substrate in Dixon plots, suggesting that they might bind to either beta-secretase subsite or to another regulatory site. Kivalues of 1 and 2 were 6.2 x 10(-5) M and 3.9 x 10(-5) M, respectively. They were less inhibitory against other enzymes such as alpha-secretase (TACE), acetylcholine esterase (AchE), chymotrypsin, and elastase, indicating that they were relatively specific inhibitors of BACE1.

Spleen tyrosine kinase participates in Src-mediated migration and proliferation by PDGF-BB in rat aortic smooth muscle cells.

Tyrosine kinases, Src and spleen tyrosine kinase (Syk), play crucial roles in cell responses to platelet-derived growth factor (PDGF) and may have their functional interactions. In this study, we focused on investigating the roles of Syk in the regulation of Src signaling in PDGF-mediated vascular cell responses. Migration, proliferation, and activity of kinases were determined in rat aortic smooth muscle cells (RASMCs). PDGF-BB (10 ng/mL) induced the migration and proliferation of RASMCs, which were significantly inhibited by PP2 (10 microM) and piceatannol (30 microM), inhibitors of Src and Syk, respectively. The phosphorylation of Syk induced by PDGF-BB was abolished by PP2. PDGF-BB increased the co-association of the PDGFbeta-receptor and the kinases, Src or Syk, and its maximal binding to Src was achieved in a shorter time than that to Syk. PDGF-BB stimulated the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) 1/2, which was inhibited by PP2 and piceatannol. PDGF-BB-induced proliferation and migration were inhibited by SB203580 (30 microM) and PD98059 (30 microM), inhibitors of p38 MAPK and ERK1/2, respectively. These results imply that Syk is regulated by Src kinase, which participates in migration and proliferation in response to PDGF-BB in RASMCs.

Analysis of peroxiredoxin decreasing oxidative stress in hypertensive aortic smooth muscle.

To determine the role of peroxiredoxin (Prx) in response to oxidative stress and during hypertension in the vasculature, we identified Prx proteins and analyzed their antioxidant effects. Rat aortic smooth muscle contains all six Prxs (I-VI). Prx I, II, and VI shifted to its acidic site on two-dimensional polyacrylamide gel electrophoresis after exposure to H(2)O(2). The total expression of Prx I and VI was increased in response to H(2)O(2). The expression of Prx I, but not that of Prx II and VI, increases and the acidic form of Prx I and the sulfonic acid form of Prx (SO(3)H-Prx) are more strongly expressed in the aortic smooth muscle of hypertensive rats than in that of normotensive control rats. Prxs were also found in the mesenteric artery, heart, and kidney. The expression levels of Prx I and VI were increased in mesenteric artery, but not heart and kidney, from hypertensive rats compared with that from normotensive rats. These results suggest that Prxs play a crucial role against oxidative stress in vascular smooth muscles during hypertension.

Endothelin-1 induces contraction via a Syk-mediated p38 mitogen-activated protein kinase pathway in rat aortic smooth muscle.

Although spleen tyrosine kinase (Syk) has crucial roles in various cells, its function on vascular smooth muscle contraction has not been determined. In the present study, we performed experiments to determine if Syk contributes to the endothelin-1 (ET-1)-mediated contraction in rat aortic smooth muscle. ET-1-induced contraction of aortic strips was inhibited by piceatannol, PD98059, and SB203580, inhibitors of Syk, extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 mitogen-activated protein kinase (MAPK), respectively. Piceatannol also attenuated high K(+)-induced contraction. ET-1 dose-dependently enhanced the activity of Syk and this was inhibited by piceatannol in both rat aortic strip and rat aortic smooth muscle cells. The phosphorylation of p38 MAPK and heat shock protein 27 (HSP27), but not that of ERK1/2, in response to ET-1 was inhibited by both piceatannol and SB203580. These results suggest that Syk may play an important role in the regulation of aortic smooth muscle contraction induced by ET-1, which may be mediated by the p38 MAPK/HSP27 signaling pathway.

Syk contributes to PDGF-BB-mediated migration of rat aortic smooth muscle cells via MAPK pathways.

OBJECTIVE: Here we investigated the role of spleen tyrosine kinase (Syk) in the migration induced by platelet-derived growth factor (PDGF) in rat aortic smooth muscle cells (RASMC). METHODS: Cell migration was determined using a Boyden chamber, by wound-healing, and by aortic ring assays. Activity of Syk, mitogen-activated protein kinase (MAPK), and heat shock protein 27 (HSP27) were tested using immunoblotting with kinase inhibitors and small interference RNAs. RESULTS: PDGF-BB induced binding of Syk to the PDGFbeta receptor and increased the phosphorylation of Syk and migration in RASMC. These effects of PDGF-BB were inhibited by piceatannol, an inhibitor of Syk. PDGF-BB increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38 MAPK, and HSP27, which were significantly inhibited by piceatannol and in Syk-knockdown cells. The p38 MAPK inhibitor SB203580 and ERK1/2 inhibitor PD98059 inhibited the migration, which was further inhibited by the combination of these inhibitors. SB203580, but not PD98059, inhibited the phosphorylation of HSP27 induced by PDGF-BB in RASMC. PDGF-BB-induced migration was attenuated in HSP27-knockdown cells. Kinase inhibitors and Syk-knockdown diminished PDGF-BB-induced sprout outgrowth in the aortic ring assay. CONCLUSIONS: These results imply that Syk is an upstream signal of the p38 MAPK/HSP27 and ERK1/2 pathways that contributes to PDGF-BB-mediated migration in RASMC.

Phorbol ester-induced contraction through p38 mitogen-activated protein kinase is diminished in aortas from DOCA-salt hypertensive rats.

The role of mitogen-activated protein kinase (MAPK) in the decreased contractile response to phorbol ester in aortic smooth muscle strips from deoxycorticosterone acetate (DOCA)-salt hypertensive rats was examined. Norepinephrine (NE) evoked greater contractility in aortic strips from DOCA rats than in those of sham-operated rats. 12-Deoxyphorbol 13-isobutyrate (DPB) induced contraction in Ca2+-free medium, which was diminished in strips from DOCA rats compared to sham-operated rats. Vasoconstrictions induced by these stimulants were inhibited by SB203580 and PD098059, inhibitors of p38 MAPK and extracellular signal-regulated kinase (ERK) 1/2, respectively, in both strips. The phosphorylation of p38 MAPK and ERK1/2 induced by NE was greater in strips from DOCA rats compared to those from sham-operated rats, and this phosphorylation was inhibited by the kinase inhibitors. DPB increased the phosphorylation of p38 MAPK and ERK1/2 in strips from both animals, and the increment of p38 MAPK phosphorylation by the stimulant was diminished in strips from DOCA rats compared to sham-operated rats. These findings suggest that the Ca2+-independent contraction evoked by DPB results from the activation of MAPKs in rat aortic smooth muscle and that the attenuated contractility by DPB in DOCA rat appears to be associated with diminished p38 MAPK activity.

Proteomic profiling and identification of cofilin responding to oxidative stress in vascular smooth muscle.

We used 2-DE and MALDI-TOF/TOF to identify proteins of vascular smooth muscle cells whose expression was or was not altered by exposure to 500 microM H2O2 for 30 min. We detected more than 800 proteins on silver-stained gels of whole protein extracts from rat aortic smooth muscle strips. Of these proteins, 135 clearly unaffected and 19 having levels altered by exposure to H2O2 were identified. Protein characterization revealed that the most prominent vascular smooth muscle proteins were those with antioxidant, cytoskeletal structure, or muscle contraction. In addition, cofilin, an isoform of the actin depolymerizing factor family, shifted to its basic site on the 2-DE gel as a result of H2O2 treatment. In Western blot analysis of proteins from A7r5 aortic smooth muscle cells, the phosphorylation, but not the expression, of cofilin was decreased by H2O2 in a dose-dependent manner. The H2O2-induced dephosphorylation of cofilin and apoptosis was inhibited by Na3VO4, an inhibitor of protein tyrosine phosphatase (PTP). These results suggest that cofilin is one of the proteins regulated by H2O2 treatment in vascular smooth muscle, and has an important role in the induction of vascular apoptosis through PTP-dependent mechanisms.

Epidermal growth factor induces vasoconstriction through the phosphatidylinositol 3-kinase-mediated mitogen-activated protein kinase pathway in hypertensive rats.

We investigated whether increased contractile responsiveness to epidermal growth factor (EGF) is associated with altered activation of mitogen-activated protein kinase (MAPK) in the aortic smooth muscle of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. EGF induced contraction and MAPK activity in aortic smooth muscle strips, which were significantly increased in tissues from the DOCA-salt hypertensive rats compared with those from sham-operated rats. AG1478, PD98059, and LY294002, inhibitors of EGF receptor (EGFR) tyrosine kinase, MAPK/extracellular signal-regulated kinase (ERK) kinase, and phosphatidylinositol 3-kinase (PI3K), respectively, inhibited the contraction and the activity of ERK1/2 that were elevated by EGF. Y27632 and GF109203X, inhibitors of Rho kinase and protein kinase C, respectively, attenuated EGF-induced contraction, with no diminution of ERK1/2 activity. Although EGF also elevated the activity of EGFR tyrosine kinase in both sham-operated and DOCA-salt hypertensive rats, the expression and the magnitude of activation did not differ between strips. These results strongly suggest that EGF induces contraction by the activation of ERK1/2, which is regulated by the PI3K pathway in the aortic smooth muscle of DOCA-salt hypertensive rats.

c-Jun N-terminal kinase contributes to norepinephrine-induced contraction through phosphorylation of caldesmon in rat aortic smooth muscle.

Vascular smooth muscle contraction is mediated by activation of extracellular signal-regulated kinase (ERK) 1/2, an isoform of mitogen-activated protein kinase (MAPK). However, the role of stress-activated protein kinase/c-Jun N-terminal kinase (JNK) in vascular smooth muscle contraction has not been defined. We investigated the role of JNK in the contractile response to norepinephrine (NE) in rat aortic smooth muscle. NE evoked contraction in a dose-dependent manner, and this effect was inhibited by the JNK inhibitor SP600125. NE increased the phosphorylation of JNK, which was greater in aortic smooth muscle from hypertensive rats than from normotensive rats. NE-induced JNK phosphorylation was significantly inhibited by SP600125 and the conventional-type PKC (cPKC) inhibitor Gö6976, but not by the Rho kinase inhibitor Y27632 or the phosphatidylinositol 3-kinase inhibitor LY294002. Thymeleatoxin, a selective activator of cPKC, increased JNK phosphorylation, which was inhibited by Gö6976. SP600125 attenuated the phosphorylation of caldesmon, an actin-binding protein whose phosphorylation is increased by NE. These results show that JNK contributes to NE-mediated contraction through phosphorylation of caldesmon in rat aortic smooth muscle, and that this effect is regulated by the PKC pathway, especially cPKC.