Regioselective Arylation of Amidoaryne Precursors via Ag-Mediated Intramolecular Oxy-Argentation.

An unprecedented silver-mediated intramolecular oxy-argentation of 3-amidoaryne precursors that quickly generates a heteroarylsilver species is developed. AgF acts as both a stoichiometric fluoride source and a reagent for the formation of a benzoxazolylsilver intermediate via aryne generation. Pd-catalyzed coupling reactions of (hetero)aryl iodides with a silver species, generated in situ, allow for the synthesis of various C7-arylated benzoxazoles. As a result, an aryl group is selectively introduced into the meta-position of 3-amidobenzyne precursors. Mechanistic studies have indicated the presence of a benzoxazolylsilver intermediate and revealed that the reaction proceeds via an intramolecular oxy-argentation process, which is initiated by a direct fluoride attack on the silyl group.

Effect of fibrin glue as an adjuvant to hang-back surgery.

BACKGROUND: The hang-back surgery is a useful technique in the field of strabismus surgery. The aim of this study is to determine the stabilizing effects of fibrin glue as an adjuvant to hang-back surgery. MATERIALS AND METHODS: Four (4)-mm hang-back recessions of the superior rectus muscle was performed in 32 eyes of 16 rabbits. Only in the left eye of the 16 rabbits, fibrin glue was applied between the recessed muscle bed and the sclera at the end of hang-back surgery (fibrin glue group). After 6 weeks, we compared the stability of the recessed rectus muscle between the fibrin glue group and the control group by evaluating the displacement of the muscle. RESULTS: The frequency of stable insertion of the recessed muscle at the intended site was greater in the fibrin glue group (9 eyes) compared to the control group (3 eyes) (p=0.028). In the control group, 5 eyes showed anterior displacement and 8 eyes showed posterior displacement and in the fibrin glue group, 1 eye showed anterior displacement, and 6 eyes showed posterior displacement. Anterior displacement was more common in the control group (6.3% Vs 31.3%). The control group and the fibrin glue group showed similar histological findings on microscopic examination. CONCLUSIONS: Fibrin glue is effective in stabilizing the new rectus muscle insertion and decreasing the displacement in the hang-back surgery.

Cell cycle regulators are critical for maintaining the differentiation potential and immaturity in adipogenesis of adipose-derived stem cells.

A single cell division is governed by the catalytic reactions of cyclins and cyclin-dependent kinases (CDKs). Stem cells are unique in that they can differentiate into tissue-specific cell types (lineage commitment) during cell division (self-renewal). In this study, we analyzed changes in the differentiation potency of adipose tissue-derived stem cells (ADSCs) according to the number of spontaneous cell divisions. We used low passage number (p3) to late passage number (p60) adipose-derived stem cells (ADSCs) as our model system. A preliminary investigation of the typical stem cell phenotypes revealed that CD44 expression decreased remarkably as the passage number of the ADSCs increased. Further examinations revealed that the higher the cell passage number, the lower the cell proliferation capability, differentiation potency, and expression of stem cell transcriptional factors and cell cycle regulators such as cyclins E, A, B, CDK2, and CDK1/CDC2. To verify if the observed changes in differentiation potency according to the number of cell divisions were related to cell cycle regulators, p3 ADSCs were treated with the selective CDK2 and CDK1/CDC2 inhibitor Purvalanol A. Inhibitor treatment of p3 ADSCs induced changes in the morphology, differentiation potency, and pattern of stem cell transcriptional factor expression so that these low passage ADSCs more closely resembled high-passage ADSCs. Collectively, our results indicate that cell cycle regulators control the differentiation potency of ADSCs, and provide insights into the cell biology and differentiation potency of ADSCs according to the number of cell divisions.

Exosomes from ovarian cancer cells induce adipose tissue-derived mesenchymal stem cells to acquire the physical and functional characteristics of tumor-supporting myofibroblasts.

OBJECTIVE: Most tumor tissue is composed of parenchymal tumor cells and tumor stroma. Mesenchymal stem cells (MSCs) can function as precursors for tumor stromal cells, including myofibroblasts, which provide a favorable environment for tumor progression. A close relationship between tumor cells and MSCs in a tumor microenvironment has been described. Exosomes are small membrane vesicles that are enriched with a discrete set of cellular proteins, and are therefore expected to exert diverse biological functions according to cell origin. METHODS: In the current study, we determined the biological effect of exosomes from two ovarian cancer cell lines (SK-OV-3 and OVCAR-3) on adipose tissue-derived MSCs (ADSCs). RESULTS: Exosome treatment induced ADSCs to exhibit the typical characteristics of tumor-associated myofibroblasts, with increased expression of α-SMA, and also increased expression of tumor-promoting factors (SDF-1 and TGF-ß). This phenomenon was correlated with an increased expression of TGF-ß receptors I and II. Analysis of TGF-ß receptor-mediated downstream signaling pathways revealed that each exosome activated different signaling pathways, showing that exosomes from SK-OV-3 cells increased the phosphorylated form of SMAD2, which is essential in the SMAD-dependent pathway, whereas exosomes from OVCAR-3 cells increased the phosphorylated form of AKT, a representative SMAD-independent pathway. Taken together, exosomes from ovarian cancer cells induced the myofibroblastic phenotype and functionality in ADSCs by activating an intracellular signaling pathway, although the activated pathway could differ from exosome-to-exosome. CONCLUSION: The current study suggested that ovarian cancer-derived exosomes contribute to the generation of tumor-associated myofibroblasts from MSCs in tumor stroma.

Endovascular management for isolated spontaneous dissection of the superior mesenteric artery: report of two cases and literature review.

The clinical course and treatment strategies of isolated superior mesenteric artery (SMA) dissection have not been fully investigated. Two cases of uncontrolled abdominal pain caused by isolated SMA dissection were successfully treated with percutaneous endovascular stent placement. At follow-up 6 months later, computed tomography confirmed that the lesions had stabilized. The patients remained symptom free at 14- and 13-month follow-up, respectively. The present report describes these two cases of isolated SMA dissection treated successfully with percutaneous endovascular stent placement, along with a review of the related literature.

Comparative intraocular penetration of 4 fluoroquinolones after topical instillation.

PURPOSE: To compare the intraocular penetration of 4 fluoroquinolone eye drops after topical instillation into rabbit eyes. METHODS: The tested drugs were levofloxacin 1.5% (LVFX), gatifloxacin 0.3%, moxifloxacin 0.5% (MFLX), and besifloxacin 0.6% (BFLX). Forty-eight New Zealand white rabbits were randomly assigned into 2 groups. For group 1 (40 rabbits, 80 eyes), single instillation was performed, and tissue samples were acquired after 0.5, 1, 2, 4, and 6 hours. For group 2 (8 rabbits, 16 eyes), repeated instillation was performed (4 times, every 15 minutes), and tissues were acquired 1 hour after the fourth instillation. The drug concentrations in ocular tissues (cornea, aqueous, conjunctiva, and trisected vitreous) were analyzed with high-performance liquid chromatography. RESULTS: The AUC 0-6 h (area under the curve, in microgram.hour/gram) in group 1 and the mean concentration (in micrograms/gram) in group 2 for LVFX, gatifloxacin 0.3%, MFLX, and BFLX, respectively, were 22.97, 6.44, 13.54, and 3.29 and 22.60, 6.99, 13.69, and 1.91 in cornea; 5.66, 1.43, 3.38, and 0.42 and 5.52, 1.29, 2.47, and 0.19 in aqueous humor; 2.33, 0.91, 2.17, and 9.83 and 4.51, 0.78, 1.48, and 2.09 in bulbar conjunctiva; 0.243, 0.051, 0.134, and 0.018 and 0.182, 0.055, 0.122, and 0.015 in anterior vitreous; none of the drugs achieved enough concentration in equatorial and posterior vitreous. Repeated instillation resulted in approximately 2.1 times greater penetration than single instillation. CONCLUSIONS: LVFX and MFLX demonstrated good intraocular penetration particularly in cornea, aqueous humor, and anterior vitreous, and they may be considered the penetrative fluoroquinolones. BFLX showed high concentration in bulbar conjunctiva and may be considered the retentive fluoroquinolone.

Incidence of Cholangiocarcinoma with or without Previous Resection of Liver for Hepatolithiasis.

BACKGROUND/AIMS: To investigate the incidence of cholangiocarcinoma in patients with hepatolithiasis with or without previous resection of liver. METHODS: From 2002 to 2009, we retrospectively reviewed 117 patients who were diagnosed and treated for hepatolithiasis in Korea University Guro Hospital. Among the 117 patients, 55 patients who were lost during follow-up were excluded, and 62 patients were eligible for analysis. The hepatic resection group (n=25) included patients who underwent left hemihepatectomy (n=2); left lateral segmentectomy (n=10); left lobectomy (n=9); right lobectomy (n=3); or wedge resection (n=1). The nonhepatic resection group (n=37) included transhepatic cholangiographic lithotomy and endoscopic retrograde cholangiopancreatography-treated patients. The mean follow-up period was 47 months. RESULTS: The incidence of cholangiocarcinoma while patients were followed for hepatolithiasis was 12.9% (8/62) (hepatic resection group, three cases [12%] vs nonhepatic resection group, five cases [13.5%]; p=1.000). The mean follow-up period was 53 months (47±11 months) until the diagnosis of cholangiocarcinoma. CONCLUSIONS: There was no difference in the incidence of cholangiocarcinoma according to previous liver resections. Patients with hepatolithiasis should be carefully followed up for detection of cholangiocarcinoma even after a previous liver resection.

Effects of the temporary placement of a self-expandable metallic stent in benign pyloric stenosis.

BACKGROUND/AIMS: The use of self-expandable metallic stents (SEMS) is an established palliative treatment for malignant stenosis in the gastrointestinal tract; therefore, its application to benign stenosis is expected to be beneficial because of the more gradual and sustained dilatation in the stenotic portion. We aimed in this prospective observational study to evaluate the efficacy and safety of temporary SEMS placement in benign pyloric stenosis. METHODS: Twenty-two patients with benign stenosis of the prepylorus, pylorus, and duodenal bulb were enrolled and underwent SEMS placement. We assessed symptom improvement, defined as an increase of at least 1 degree in the gastric-outlet-obstruction scoring system after stent insertion. RESULTS: No major complications were observed during the procedures. After stent placement, early symptom improvement was achieved in 18 of 22 patients (81.8%). During the follow-up period (mean 10.2 months), the stents remained in place successfully for 6 to 8 weeks in seven patients (31.8%). Among the 15 patients (62.5%) with stent migration, seven (46.6%) showed continued symptomatic improvement without recurrence of obstructive symptoms. CONCLUSIONS: Despite the symptomatic improvement, temporary SEMS placement is premature as an effective therapeutic tool for benign pyloric stenosis unless a novel stent is developed to prevent migration.

Exosomes from breast cancer cells can convert adipose tissue-derived mesenchymal stem cells into myofibroblast-like cells.

Exosomes are small membrane vesicles secreted into the extracellular environment by various types of cells, including tumor cells. Exosomes are enriched with a discrete set of cellular proteins, and therefore expected to exert diverse biological functions according to cell origin. Mesenchymal stem cells (MSCs) possess the potential for differentiation into multilineages and can also function as precursors for tumor stroma including myofibroblast that provides a favorable environment for tumor progression. Although a close relationship between tumor cells and MSCs in a neoplastic tumor microenvironment has already been revealed, how this communication works is poorly understood. In this study, we investigated the influence of tumor cell-derived exosomes on MSCs by treating adipose tissue-derived MSCs (ADSCs) with breast cancer-derived exosomes. The exosome-treated ADSCs exhibited the phenotypes of tumor-associated myofibroblasts with increased expression of α-SMA. Exosome treatment also induced increased expression of tumor-promoting factors SDF-1, VEGF, CCL5 and TGFß. This phenomenon was correlated with increased expression of TGFß receptor I and II. Analysis of SMAD2, a key player in the TGFß receptor-mediated SMAD pathway, revealed that its phosphorylation was increased by exosome treatment and was inhibited by treatment with SB431542, an inhibitor of the SMAD-mediated pathway, resulting in decreased expression of α-SMA. Taken together, our results show that tumor-derived exosomes induced the myofibroblastic phenotype and functionality in ADSCs via the SMAD-mediated signaling pathway. In conclusion, this study suggests that tumor-derived exosomes can contribute to progression and malignancy of tumor cells by converting MSCs within tumor stroma into tumor-associated myofibroblasts in the tumor microenvironment.

MicroRNA expression profiling in neurogenesis of adipose tissue-derived stem cells.

Adipose tissue-derived stem cells (ADSCs) are one population of adult stem cells that can self renew and differentiate into multiple lineages. Because of advantages in method and quantity of acquisition, ADSCs are gaining attention as an alternative source of bone marrow mesenchymal stem cells. In this study, we performed microRNA profiling of undifferentiated and of neurally-differentiated ADSCs to identify the responsible microRNAs in neurogenesis using this type of stem cell. MicroRNAs from four different donors were analysed by microarray. Compared to the undifferentiation control, we identified 39-101 microRNAs with more than two-fold higher expression and 3-9 microRNAs with two-fold lower expression. The identified microRNAs were further analysed in terms of gene ontology (GO) in relation with neurogenesis, based on their target mRNAs predicted by computational analysis. This study revealed the specific microRNAs involved in neurogenesis via microRNA microarray, and may provide the basic information for genetic induction of adult stem cell differentiation using microRNAs.

Hyperthermia-treated mesenchymal stem cells exert antitumor effects on human carcinoma cell line.

BACKGROUND: Mesenchymal stem cells (MSCs) possess the potential for differentiation into multilineages. MSCs have been reported to play a role as precursors for tumor stroma in providing a favorable environment for tumor progression. Hyperthermia destroys cancer cells by raising the temperature of tumor-loaded tissue to 40 degrees C to 43 degrees C and causes indirect sensitizing effects when combined with chemo- and/or radiotherapy. However, how hyperthermia affects the tumor-supportive stroma is unknown. Here, the authors investigated the effects of hyperthermia-treated MSCs, from different sources, on the human ovarian cancer cell line SK-OV-3. METHODS: MSCs from adipose tissue and amniotic fluid were untreated or heat-treated (HS-MSCs). The culture supernatant of each treatment group was collected and transferred to the SK-OV-3 cells. RESULTS: The morphological analysis and cell proliferation assay showed a reduced viability of the tumor cells in the conditioned medium with the HS-MSCs. Further investigations revealed that the conditioned medium of the HS-MSCs induced a higher nuclear condensation and a greater number of sub-G1 cells among the tumor cells. Analysis of the mRNA expression demonstrated that the conditioned medium of the HS-MSCs induced up-regulation or down-regulation of several tumor-associated molecules. Finally, the cytokine array of each conditioned medium showed that angiogenin, insulin-like growth factor binding protein 4, neurotrophin 3, and chemokine (C-C motif) ligand 18 are involved as main factors. CONCLUSIONS: This study showed that the conditioned medium of the HS-MSCs exerted a suppressive effect on tumor progression and malignancy, suggesting that hyperthermia enables tumor stromal cells to provide a sensitizing environment for tumor cells to undergo cell death.