Early complications after percutaneous radiofrequency ablation for hepatocellular carcinoma: an analysis of 1,843 ablations in 1,211 patients in a single centre: experience over 10 years.

AIM: To evaluate the incidence of adverse events and associated factors after radiofrequency ablation (RFA) in patients with hepatocellular carcinoma within 30 days. MATERIALS AND METHODS: The early complications that occurred within 30 days after RFA at a single institution from January 2000 to July 2010 were reviewed in order to evaluate the morbidity, mortality, and risk factors associated with the complications. In total, 1,211 patients (845 men, 70.5%) with a mean age of 68 years (range, 27-88 years) underwent 1,843 RFA procedures. RESULTS: The overall incidence rate of complications was 6.8% (125 cases). Major complications (n=36, 2%) included liver abscess (n=15, 0.8%), intraperitoneal bleeding (n=8, 0.4%), liver failure (n=5, 0.3%), variceal bleeding (n=3, 0.2%), haemothorax (n=2, 0.1%), cholecystitis (n=2, 0.1%), and bowel perforation (n=1, 0.1%). Among the minor complications (n=89, 4.8%), the most common was the post RFA syndrome accompanied by pain and fever (n=75, 4.1%). Other minor complications included significant pleural effusion (n=7, 0.4%), skin wound infection (n=4, 0.2%), and thermal injuries to the skin (n=3, 0.2%). Procedural infections significantly increased with tumour size (OR=1.379; 95% confidence interval [CI], 1.191-1.579; p<0.001), and multiple overlapping ablations (OR=1.118; 95% CI, 1.019-1.227, p=0.018). Thrombocytopenia (<50,000/µl), prothrombin time, and serum albumin level were significantly associated with post-RFA bleeding episodes (p=0.041, p=0.021, and p=0.003, respectively). The overall mortality rate was 0.3% (three cases of hepatic failure, two case of sepsis, and one case of renal failure). CONCLUSIONS: RFA is a safe and effective local treatment for hepatocellular carcinoma. Careful selection of patients and appropriate RFA planning could decrease procedural mortality and morbidity.

Influence of esophagectomy on the gastroesophageal reflux in patients with esophageal cancer.

This study aims to assess the influence of esophagectomy with gastric transposition on the gastroesophageal reflux (GER) and gastric acidity in patients with esophageal cancer. Data on 53 esophageal cancer patients who underwent 24-hour impedance-pH monitoring after esophagectomy were retrospectively analyzed. We used a solid-state esophageal pH probe in which the esophageal pH sensor is placed 1.5 cm distal to the upper esophageal sphincter and the gastric pH sensor is located 15 cm distal to the esophageal pH channel. 24-hour impedance-pH monitoring data and other clinical data including anastomosis site stricture and incidence of pneumonia were collected. We defined pathologic reflux with reference to known normative data. Stricture was defined when an intervention such as bougienage or balloon dilatation was required to relieve dysphagia. The esophageal and gastric mean pH were 5.47 ± 1.51 and 3.33 ± 1.64, respectively. The percent time of acidic pH (<4) was 6.66 ± 12.49% in the esophagus and 70.53 ± 32.19% in the stomach. Esophageal pathologic acid reflux was noticed in 32.1%, 20.8%, and 35.8% during total, upright, and recumbent time, respectively. Esophageal pathologic bolus reflux was noted in 83.0%, 77.4%, and 64.2% during total, upright, and recumbent time, respectively. Gastric acidity increased with time after esophagectomy. Esophageal acid exposure time correlated with intragastric pH. However, esophageal pathologic acid reflux was not associated with anastomosis site stricture or pneumonia. In conclusion, GER frequently occurs after esophagectomy. Thus, strict lifestyle modifications and acid suppression would be necessary in patients following esophagectomy.

Giant magneto-elastic coupling in multiferroic hexagonal manganites.

The motion of atoms in a solid always responds to cooling or heating in a way that is consistent with the symmetry of the given space group of the solid to which they belong. When the atoms move, the electronic structure of the solid changes, leading to different physical properties. Therefore, the determination of where atoms are and what atoms do is a cornerstone of modern solid-state physics. However, experimental observations of atomic displacements measured as a function of temperature are very rare, because those displacements are, in almost all cases, exceedingly small. Here we show, using a combination of diffraction techniques, that the hexagonal manganites RMnO3 (where R is a rare-earth element) undergo an isostructural transition with exceptionally large atomic displacements: two orders of magnitude larger than those seen in any other magnetic material, resulting in an unusually strong magneto-elastic coupling. We follow the exact atomic displacements of all the atoms in the unit cell as a function of temperature and find consistency with theoretical predictions based on group theories. We argue that this gigantic magneto-elastic coupling in RMnO3 holds the key to the recently observed magneto-electric phenomenon in this intriguing class of materials.

The beneficial effect of palliative resection in metastatic colorectal cancer.

BACKGROUND: We aimed to determine the role of palliative resection in metastatic colorectal cancer (mCRC) and ascertain which patient populations would benefit most from this treatment. METHODS: A total of 1015 patients diagnosed with mCRC at Seoul National University Hospital between 2000 and 2009 were retrospectively studied. RESULTS: Of the 1015 patients, 168 patients with only liver and/or lung metastasis received curative resection. The remaining 847 patients were treated with palliative chemotherapy and/or palliative resection combined with best supportive care. Palliative resection was performed in 527 (62.2%) cases (complete resection with negative margin (R0) in 93, R1/2 in 434). Resected patients had a more prolonged median overall survival (OS) than unresected patients (21.3 vs 14.1 months; P<0.001). In multivariate analysis, R0 resection was found to be associated with a superior OS compared with R1/2 resection (51.3 vs 19.1 months; P<0.001) and no resection (51.3 vs 14.1 months; P<0.001). When we performed propensity score matching, palliative resection was found to be related to prolonged OS (hazard ratio=0.72, 95% confidence interval=0.59-0.89; P=0.003). CONCLUSION: Palliative resection without residual disease and chemotherapy confers a longer-term survival outcome than palliative chemotherapy alone in mCRC patient subset.

Prognostic implication of mucinous histology in colorectal cancer patients treated with adjuvant FOLFOX chemotherapy.

BACKGROUND: There have been controversies in prognostic impact of mucinous histology on colorectal cancer, and its implication in patients treated with adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) is unclear. METHODS: Stage II and III colorectal cancer patients who underwent curative resection followed by adjuvant FOLFOX were included. Patients were grouped according to the mucinous content: >50%, mucinous adenocarcinoma (MAC); <50%, adenocarcinoma with intermediated mucinous component (AIM); and without any mucinous component, non-MAC (NMA). Clinicopathological features and disease-free survival (DFS) were compared. RESULTS: Among a total of 521 patients, 27 patients (5.2%) had MAC, 41 patients (7.9%) had AIM, and 453 patients (86.9%) had NMA. Mucinous adenocarcinoma and AIM had higher frequency of proximal location and microsatellite instability, but lower frequency of angiolymphatic invasion. Disease-free survival was significantly worse in the MAC compared with NMA (3-year DFS 57% and 86%, respectively; P<0.001) and AIM (3-year DFS 87%, P=0.01 vs MAC). Multivariate analysis revealed MAC as an independent negative prognostic factor of DFS (adjusted hazard ratio 7.96, 95% confidence interval 3.76-16.8). CONCLUSION: Adenocarcinoma with intermediated mucinous component and MAC have distinct clinicopathological features compared with NMA. Mucinous adenocarcinoma has an adverse prognostic impact on stage II or III colorectal cancer treated with adjuvant FOLFOX.

Methylation of the CDH1 promoter as the second genetic hit in hereditary diffuse gastric cancer.

Aberrant promoter methylation and the associated loss of gene expression is a common accompaniment of human cancers. Nonetheless, it has been challenging to demonstrate in any given tumour that methylation of a specific gene was causal and not consequent to malignant transformation. In this regard, our attention was drawn to the genesis of gastric cancers in individuals with hereditary diffuse gastric cancer (HDGC). These individuals harbour germline mutations in the gene encoding E-cadherin, CDH1, but their cancers have consistently demonstrated absence of loss of heterozygosity at the CDH1 locus. These findings suggested the hypothesis that CDH1 promoter methylation might function as the 'second genetic hit' in the genesis of these cancers.

Common variant in 6q26-q27 is associated with distal colon cancer in an Asian population.

BACKGROUND AND AIM: Colorectal cancer (CRC) is a multifactorial disease with both environmental and genetic factors contributing to its development. The incidence of CRC is increasing year by year in Japan. Patients with CRC in advanced stages have a poor prognosis, but detection of CRC at earlier stages can improve clinical outcome. Therefore, identification of epidemiologial factors that influence development of CRC would facilitate the prevention or early detection of disease. METHODS: To identify loci associated with CRC risk, we performed a genome-wide association study (GWAS) for CRC and sub-analyses by tumour location using 1583 Japanese CRC cases and 1898 controls. Subsequently, we conducted replication analyses using a total of 4809 CRC cases and 2973 controls including 225 Korean subjects with distal colon cancer and 377 controls. RESULTS: We identified a novel locus on 6q26-q27 region (rs7758229 in SLC22A3, p = 7.92 × 10⁻9, OR of 1.28) that was significantly associated with distal colon cancer. We also replicated the association between CRC and SNPs on 8q24 (rs6983267 and rs7837328, p = 1.51 × 10⁻8 and 7.44 × 10⁻8, ORs of 1.18 and 1.17, respectively). Moreover, we found cumulative effects of three genetic factors (rs7758229, rs6983267, and rs4939827 in SMAD7) and one environmental factor (alcohol drinking) which appear to increase CRC risk approximately twofold. CONCLUSIONS: We found a novel susceptible locus in SLC22A3 that contributes to the risk of distal colon cancer in an Asian population. These findings would further extend our understanding of the role of common genetic variants in the aetiology of CRC.

Low doses of the novel caspase-inhibitor GS-9450 leads to lower caspase-3 and -8 expression on peripheral CD4+ and CD8+ T-cells.

Chronic hepatitis C virus (HCV) infection is characterized by increased rates of apoptotic hepatocytes and activated caspases have been shown in HCV-infected patients. GS-9450, a novel caspase-inhibitor has demonstrated hepatoprotective activity in fibrosis/apoptosis animal models. This study evaluated the effects of GS-9450 on peripheral T-cell apoptosis in chronic HCV-infected patients. As sub study of the GS-US-227-0102, a double-blind, placebo-controlled phase 2a trial evaluating the safety and tolerability of GS-9450, apoptosis of peripheral CD4+ and CD8+ T-cells was measured using activated caspase-3, activated caspase-8 and CD95 (Fas). Blood samples were drawn at baseline, day 14 after therapy and at 5 weeks off-treatment follow-up in the first cohort of 10 mg. In contrast to the placebo-treated patients, GS-9450 caused a median of 46% decrease in ALT-values from baseline to day 14 in all treated patients (median of 118-64 U/l) rising again to a median of 140 U/l (19%) at 5 weeks off-treatment follow-up. In GS9450-treated patients, during treatment and follow-up, percentages of activated caspase-3+ and caspase-8 expression tended to decrease, in contrast to placebo-treated patients. Interestingly, compared to healthy controls, higher percentages of caspase-3 and caspase-8 positive CD4+ and CD8+ T-cells were demonstrated in HCV-infected patients at baseline. Decreased ALT-values were observed in all HCV-infected patients during treatment with low dose of the caspase-inhibitor GS-9450 accompanied by a lower expression of caspase-3 and -8 on peripheral T-cells. Furthermore, at baseline percentages of activated caspase-3, activated caspase-8 and CD95+ T-cells were higher in chronic HCV-infected patients compared to healthy controls.

Electrical conductivity modeling and experimental study of densely packed SWCNT networks.

Single-walled carbon nanotube (SWCNT) networks have become a subject of interest due to their ability to support structural, thermal and electrical loadings, but to date their application has been hindered due, in large part, to the inability to model macroscopic responses in an industrial product with any reasonable confidence. This paper seeks to address the relationship between macroscale electrical conductivity and the nanostructure of a dense network composed of SWCNTs and presents a uniquely formulated physics-based computational model for electrical conductivity predictions. The proposed model incorporates physics-based stochastic parameters for the individual nanotubes to construct the nanostructure such as: an experimentally obtained orientation distribution function, experimentally derived length and diameter distributions, and assumed distributions of chirality and registry of individual CNTs. Case studies are presented to investigate the relationship between macroscale conductivity and nanostructured variations in the bulk stochastic length, diameter and orientation distributions. Simulation results correspond nicely with those available in the literature for case studies of conductivity versus length and conductivity versus diameter. In addition, predictions for the increasing anisotropy of the bulk conductivity as a function of the tube orientation distribution are in reasonable agreement with our experimental results. Examples are presented to demonstrate the importance of incorporating various stochastic characteristics in bulk conductivity predictions. Finally, a design consideration for industrial applications is discussed based on localized network power emission considerations and may lend insight to the design engineer to better predict network failure under high current loading applications.

Galectin-3 stabilizes heterogeneous nuclear ribonucleoprotein Q to maintain proliferation of human colon cancer cells.

Comparative analysis of proteomes using 5-fluorouracil (5-FU)-resistant human colon cancer cell line revealed that decreased galectin-3 expression was significantly associated with retarded proliferation. However, in the presence of 5-FU proliferation rate of cells with suppressed galectin-3 expression did not differ from that of cells with normal galectin-3 expression, even galectin-3 suppression augmented apoptosis. Mechanism by which galectin-3 regulates cancer cell proliferation has been identified in immunoprecipitates of the anti-galectin-3 antibody. Heterogeneous nuclear ribonucleoprotein Q (hnRNP Q) was identified as a protein interacting with galectin-3. Interestingly, while galectin-3 protein was not affected by the hnRNP Q level, its suppression was accompanied by a decrease in hnRNP Q expression. The present study demonstrates that galectin-3 stabilizes hnRNP Q via complex formation, and reduction in the hnRNP Q level leads to slow proliferation and less susceptibility to 5-FU.

Permanent makeup removal using Q-switched Nd:YAG laser.

Red-brown tattoos are usually treated with a frequency-doubled Q-switched (QS) neodymium:yttrium-aluminum-garnet Nd:YAG laser (532 nm), because red and pink pigments show maximum absorption between 500 and 570 nm. Using a QS laser for red-brown tattoo removal has sometimes led to paradoxical darkening of the tattoo pigments, and this darkened grey-black colour may be difficult to remove. A woman with red-brown cosmetic tattoos on her eyebrows was treated using a QS Nd:YAG laser (1064 nm) initially with low fluence and subsequently with increasing fluences at 6-weekly intervals. After the first treatment, a slight darkening of the tattoo pigments was seen, but this faded and complete clearance was achieved after five treatments. There was no downtime during every treatment and there were no scars, pigmentary alterations or textural changes.

In vitro performance of nano-heterogeneous dentin adhesive.

Water is ubiquitous in the mouths of healthy individuals and routinely interferes with efforts to bond restorations to dental tissues. Our previous studies using tapping-mode atomic force microscopy (TMAFM) have shown that nanophase separation is a general feature of cross-linked polymethacrylates photocured in the presence of water. To explore the relationship between nanophase separation in dentin adhesives and their long-term mechanical properties, we evaluated model adhesives after 3 months of aqueous storage. The degree of contrast in the TMAFM phase image depended on the formulations used, ranging from 'not observable' to 'very strong'. Correspondingly, the mechanical properties of these model adhesives varied from 'minimal change' to 'significant depreciation'. The results support the hypothesis that a high degree of heterogeneity at the nano-scale is associated with poor mechanical durability in these model adhesives.

Depo-medroxyprogesterone in women on antiretroviral therapy: effective contraception and lack of clinically significant interactions.

We conducted an open-label, steady-state pharmacokinetic (PK) study of drug interactions among HIV-infected women treated with depo-medroxyprogesterone acetate (DMPA) while on nucleoside analogues plus nelfinavir (N=21), efavirenz (N=17), or nevirapine (N=16); or nucleosides only or no antiretroviral therapy as a control group (N=16). PK parameters were estimated using non-compartmental analysis, with between-group comparisons of medroxyprogesterone acetate (MPA) PKs and within-subject comparisons of ARV PKs before and 4 weeks after DMPA dosing. Plasma progesterone levels were measured at baseline and at 2, 4, 6, 8, 10, and 12 weeks after DMPA dosing. There were no significant changes in MPA area under the concentration curve, peak or trough concentrations, or apparent clearance in the nelfinavir, efavirenz, or nevirapine groups compared to the control group. Minor changes in nelfinavir and nevirapine drug exposure were seen after DMPA, but were not considered clinically significant. Suppression of ovulation was maintained.

In the absence of other Fc receptors, Fc gamma RIIIA transmits a phagocytic signal that requires the cytoplasmic domain of its gamma subunit.

The transmembrane isoform of Fc gamma RIII, Fc gamma RIIIA, is found on NK cells, cultured monocytes, and tissue macrophages in association with a dimer of an accessory subunit, either gamma or zeta. Functions of individual Fc receptors have been difficult to analyze due to coexpression of the receptors on hematopoietic cells and permanent cell lines expressing Fc receptors. cDNAs for the alpha and gamma subunits of Fc gamma RIIIA were cotransfected into COS-1 cells, which lack endogenous Fc receptors, to evaluate receptor-mediated phagocytosis and changes in [Ca2+]i. Transfectants both bound and phagocytosed IgG-sensitized erythrocytes and, following activation of Fc gamma RIIIA, increased [Ca2+]i. The gamma subunit was essential both for the surface expression of the receptor and for transduction of the phagocytic signal. Truncation of the gamma subunit cytoplasmic domain (amino acids 65-80) eliminated phagocytic function. Phorbol ester inhibited phagocytosis in a concentration-dependent manner, but did not affect IgG-sensitized erythrocytes binding, suggesting that a protein kinase C-dependent pathway inhibits phagocytosis. The data indicate that a tyrosine containing cytoplasmic domain within the gamma subunit is required for phagocytosis by Fc gamma RIIIA.

Conserved cytoplasmic tyrosine residues of the gamma subunit are required for a phagocytic signal mediated by Fc gamma RIIIA.

Fc receptors for immunoglobulins are found on many cells and are important in host defense. We transfected Fc gamma RIIIA, present on macrophages and natural killer (NK) cells, into COS-1 cells to study its role in phagocytosis and calcium mobilization in the absence of other Fc gamma receptors. Human Fc gamma RIIIA-alpha (CD16) was cotransfected with its associated chains, either Fc gamma RIIIA gamma or zeta. Both gamma and zeta were observed to induce a phagocytic signal, but gamma was at least sixfold more effective than zeta. Conservative substitution by phenylalanine of either one of the two cytoplasmic tyrosine residues in the gamma chain resulted in markedly diminished phagocytosis and calcium mobilization. Tyrphostin 23, an inhibitor of tyrosine kinases, reversibly inhibited phagocytosis. Further, in vitro kinase assays with the wild type and mutant gamma chains demonstrated that the wild type gamma chain, but not the mutant gamma chains, is phosphorylated. These results suggest that the cytoplasmic tyrosine residues and tyrosine phosphorylation are required for Fc gamma RIIIA to mediate two signal transduction events: phagocytosis and calcium mobilization.

Chromogranin A expression in normal and malignant human tissues.

We used a recombinant cDNA probe for human chromogranin A to measure the expression of mRNA encoded by this gene in a variety of normal human tissues and tumor specimens using Northern blot and in situ hybridization analysis. With few exceptions, the expression of chromogranin A mRNA appears to be restricted to normal tissues and tumors of neuroendocrine lineage. However, we have detected mRNA expression of this gene in 1 of 14 cell lines and 2 of 13 tumor specimens of colon adenocarcinoma. The finding of chromogranin A expression in some colon carcinomas suggests that a previously unrecognized subgroup of these tumors has neuroendocrine features. The detection of this subgroup demonstrates the potential for improving tumor classification through the use of techniques and reagents developed by recombinant DNA technology.

Augmentation of pulmonary host defense against Pseudomonas by FcgammaRIIA cDNA transfer to the respiratory epithelium.

Fcgamma receptors on the surface of phagocytic cells bind the Fc region of IgG and mediate binding, phagocytosis, and destruction of particulate antigens opsonized by the antigen-specific IgG molecule. The present study evaluates the feasibility of converting lung epithelial cells into phagocytic cells using adenovirus (Ad) vector-mediated gene transfer of FcgammaRIIA cDNA to induce expression of the human FcgammaRIIA receptor. Binding and phagocytosis of opsonized sheep red blood cells (SRBCs) by the A549 human lung epithelial cell line after Ad-mediated FcgammaRIIA gene transfer was demonstrated using light and fluorescence microscopy and phagocytic assays with (51)Cr-labeled SRBCs. When A549 cells were infected with an Ad vector expressing a FcgammaRIIA mutant in which 2 of 3 cytoplasmic tyrosines have been replaced with phenylalanine, only binding, but not phagocytosis, of opsonized SRBCs was observed. In vivo expression of FcgammaRIIA in the lung after intratracheal administration of the AdFcgammaRIIA enhanced clearance of opsonized Pseudomonas aeruginosa from the lung in normal rats and in mice deficient in Fcgamma receptor expression. Similar results were observed with a chimeric FcgammaRIIA construct containing the extracellular domain of FcgammaRIIIA. Together, these data demonstrate that Ad-mediated FcgammaRIIA receptor cDNA expression can mediate the binding and phagocytosis of opsonized particulate antigens by normally nonphagocytic cells, suggesting that gene-transfer strategies might be used to utilize nonphagocytic cells to clear bacteria or other opsonized particulate antigens from the respiratory tract.

CpG island promoter region methylation patterns of the inactive-X-chromosome hypoxanthine phosphoribosyltransferase (Hprt) gene.

Inactive-X-chromosome genes in mammalian females have methylated CpG islands. We have questioned whether there are variable levels of cytosine methylation at different CpG sites within the island that might indicate the presence of primary sites of methylation which may be critical for the maintenance of gene repression and candidate sites for the initiation of inactivation. To address these questions, we have analyzed the methylation patterns of 32 CpG sites of the X-linked hypoxanthine phosphoribosyltransferase (Hprt) gene on the active and inactive X chromosomes of mouse tissues and cell lines, using genomic sequencing of bisulfite-treated genomic DNA. Cytosine is deaminated by bisulfite, but methylcytosine is not affected. Cell lines that were heterozygous for the Hprt deletion mutation (Hprtb-m3) and a functional Hprt allele were selected with 6-thioguanine. The resulting cell populations uniformly carry the intact Hprt allele on the inactive X chromosome. The methylation of these CpG sites was determined either by the direct sequence analysis of bisulfite-treated and amplified DNA or by the sequence analysis of clones derived from the amplified DNA. No CpG methylation was detected on the active Hprt genes from either males or the active X chromosome of females. On average, 22 CpGs were methylated in the other 50% of female DNA, and the level of methylation at individual sites varied from 42 to 100%. Analysis of the inactive Hprt gene in two cell lines showed that averages of 14 and 18 CpGs were methylated and that the frequency of methylation at 32 individual sites ranged from 3 to 100%. The highest frequency of methylation in cell lines coincided with the sequences flanking transcription initiation sites. These results suggest that methylation patterns are heterogeneous within a tissue and even in clonal cell populations and that specific subsets of CpG sites sustain high methylation frequencies which may be critical for the maintenance of X-chromosome inactivation. The bisulfite method identified which CpG sites were methylated on the inactive X chromosome, and it provided a quantitative estimate of the frequency of methylation of these sites in genomic DNA.

G(alpha)11 signaling through ARF6 regulates F-actin mobilization and GLUT4 glucose transporter translocation to the plasma membrane.

The action of insulin to recruit the intracellular GLUT4 glucose transporter to the plasma membrane of 3T3-L1 adipocytes is mimicked by endothelin 1, which signals through trimeric G(alpha)q or G(alpha)11 proteins. Here we report that murine G(alpha)11 is most abundant in fat and that expression of the constitutively active form of G(alpha)11 [G(alpha)11(Q209L)] in 3T3-L1 adipocytes causes recruitment of GLUT4 to the plasma membrane and stimulation of 2-deoxyglucose uptake. In contrast to the action of insulin on GLUT4, the effects of endothelin 1 and G(alpha)11 were not inhibited by the phosphatidylinositol 3-kinase inhibitor wortmannin at 100 nM. Signaling by insulin, endothelin 1, or G(alpha)11(Q209L) also mobilized cortical F-actin in cultured adipocytes. Importantly, GLUT4 translocation caused by all three agents was blocked upon disassembly of F-actin by latrunculin B, suggesting that the F-actin polymerization caused by these agents may be required for their effects on GLUT4. Remarkably, expression of a dominant inhibitory form of the actin-regulatory GTPase ARF6 [ARF6(T27N)] in cultured adipocytes selectively inhibited both F-actin formation and GLUT4 translocation in response to endothelin 1 but not insulin. These data indicate that ARF6 is a required downstream element in endothelin 1 signaling through G(alpha)11 to regulate cortical actin and GLUT4 translocation in cultured adipocytes, while insulin action involves different signaling pathways.

Abrogation of the Fc gamma receptor IIA-mediated phagocytic signal by stem-loop Syk antisense oligonucleotides.

The role of Syk kinase in Fc gamma receptor (Fc gamma R) IIA-mediated phagocytosis was examined with two forms of antisense oligodeoxynucleotides (ODNs) designed to hybridize to human Syk mRNA. Monocytes were incubated with linear and stem-loop antisense ODNs targeted to Syk mRNA. When complexed with cationic liposomes, stem-loop Syk antisense ODN with phosphorothioate modification exhibited stability in fetal bovine and human serum. The stem-loop Syk antisense ODN at a concentration of 0.2 microM inhibited Fc gamma RIIA-mediated phagocytosis by 90% and completely eliminated Syk mRNA and protein in monocytes, whereas scrambled-control ODNs had no effect. The Syk antisense ODNs did not change beta-actin mRNA levels and Fc gamma RII cell-surface expression. In addition, stem-loop Syk antisense ODN inhibited Fc gamma RI and Fc gamma RIIIA-mediated phagocytosis. These data indicate the efficacy of stem-loop Syk antisense ODN for targeting and degrading Syk mRNA and protein and the importance of Syk kinase in Fc gamma receptor-mediated phagocytosis. Immunoblotting assay demonstrated that Fc gamma RII tyrosine phosphorylation after Fc gamma RII cross-linking did not change in the absence of Syk protein. These results indicate that Syk kinase is required for Fc gamma RIIA-mediated phagocytic signaling and that Fc gamma RII cross-linking leads to tyrosine phosphorylation of Fc gamma RII independent of Syk kinase.