Plasma-free anisotropic selective-area etching of ß-Ga2O3 using forming gas under atmospheric pressure.

We demonstrate a facile and safe anisotropic gas etching technique for ß-Ga2O3 under atmospheric pressure using forming gas, a H2/N2 gas mixture containing 3.96 vol% H2. This etching gas, being neither explosive nor toxic, can be safely exhausted into the atmosphere, simplifying the etching system setup. Thermodynamic calculations confirm the viability of gas-phase etching above 676°C without the formation of Ga droplets. Experimental verification was achieved by etching ( 1 - 02) ß-Ga2O3 substrates within a temperature range of 700-950°C. Moreover, selective-area etching using this method yielded trenches and fins with vertical and flat sidewalls, defined by (100) facets with the lowest surface energy density, demonstrating significant anisotropic etching capability.

This paper introduces a safe, plasma-free anisotropic etching technique for ß-Ga₂O₃ using non-toxic forming gas, achieving high precision and efficiency in semiconductor processing.

Great Saphenous Vein Flow Pattern as a Simple Ultrasonographic Sign of Early Recanalization of Deep Vein Thrombosis: A Case Series Report.

We retrospectively examined patients with ultrasonographically occlusive acute proximal deep vein thrombosis (DVT). All patients were categorized into two groups on the basis of whether great saphenous vein (GSV) flow toward the common femoral vein was detected (flow [+]; n=10) or undetected (flow [-]; n=10). We investigated the relationship between the GSV flow pattern and DVT recanalization. Thrombus recanalization, which is defined as diameter reduction to lower than 40% of the vessel diameter, was confirmed in seven of the flow (+), and none of the flow (-). This study proposes that the GSV flow pattern may be a simple marker for the recanalization of proximal occlusive DVT.

The Frequency of Fish-Eating Could Negatively Associate with Visceral Adiposity in Those Who Eat Moderately.

Visceral fat accumulation is regarded as one of the major phenotypes of metabolic syndrome. There have not been enough data on the relationship between the fish-eating habit and visceral adiposity. A total of 94 male participants received abdominal CT for the measurement of the visceral fat area (VFA), serum sampling for the fatty acid composition and questionnaires about their life-style. We divided the participants into two groups: whether they ate their fill (group F, n=70) or they ate in moderation (group M, n=24). Stepwise multiple linear regression analyses showed that usual alcohol consumption and lower daily physical activity in group F, and infrequent fish-eating and frequent fat-rich deserts in group M were the significant positive correlates with the VFA. The serum eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio showed significant correlation with the frequency of fish-eating in both groups. Interestingly, in group M, the serum EPA/AA ratio negatively correlated with the VFA, while it failed in group F. In conclusion, the present data suggest that the fish-eating habit might negatively associate with visceral fat accumulation only in those who are moderate in eating in the general population.

Serum eicosapentaenoic acid/arachidonic acid ratio is low in patients with pulmonary thromboembolism.

Recently n-3 polyunsaturated fatty acids (PUFAs) have been reported to play protective roles against cardiovascular diseases. Pulmonary thromboembolism (PTE) is one of the critical diseases in the circulatory system. However the relationship between n-3 PUFAs and PTE has not been reported. A total of 144 outpatients of the division of cardiology, including 12 of PTE cases, were enrolled in the present study and serum levels of eicosapentaenoic acid (EPA) and arachidonic acid (AA) were analyzed. We found that the EPA/AA ratio of the patients with PTE (the PTE group) was significantly lower than that of the patients without PTE (the non-PTE group) (p=0.007 for log EPA/log AA ratio). Next, the PTE group was divided into two groups by the presence or absence of malignant carcinoma. The PTE without carcinoma group showed significantly lower EPA/AA ratio than that of the non-PTE group (p=0.002 for log EPA/log AA ratio). However, the PTE with carcinoma group did not show the statistical difference in EPA/AA ratio compared with the non-PTE group (p=0.39). These data indicate that PTE may be associated with a low EPA/AA ratio, although the presence of malignant carcinoma should be taken into account.

Cardiac myocyte-specific ablation of follistatin-like 3 attenuates stress-induced myocardial hypertrophy.

Transforming growth factor-ß family cytokines have diverse actions in the maintenance of cardiac homeostasis. Follistatin-like 3 (Fstl3) is an extracellular regulator of certain TGF-ß family members, including activin A. The aim of this study was to examine the role of Fstl3 in cardiac hypertrophy. Cardiac myocyte-specific Fstl3 knock-out (KO) mice and control mice were subjected to pressure overload induced by transverse aortic constriction (TAC). Cardiac hypertrophy was assessed by echocardiography and histological and biochemical methods. KO mice showed reduced cardiac hypertrophy, pulmonary congestion, concentric LV wall thickness, LV dilatation, and LV systolic dysfunction after TAC compared with control mice. KO mice displayed attenuated increases in cardiomyocyte cell surface area and interstitial fibrosis following pressure overload. Although activin A was similarly up-regulated in KO and control mice after TAC, a significant increase in Smad2 phosphorylation only occurred in KO mice. Knockdown of Fstl3 in cultured cardiomyocytes inhibited PE-induced cardiac hypertrophy. Conversely, adenovirus-mediated Fstl3 overexpression blocked the inhibitory action of activin A on hypertrophy and Smad2 activation. Transduction with Smad7, a negative regulator of Smad2 signaling, blocked the antihypertrophic actions of activin A stimulation or Fstl3 ablation. These findings identify Fstl3 as a stress-induced regulator of hypertrophy that controls myocyte size via regulation of Smad signaling.

Sfrp5 is an anti-inflammatory adipokine that modulates metabolic dysfunction in obesity.

Adipose tissue secretes proteins referred to as adipokines, many of which promote inflammation and disrupt glucose homeostasis. Here we show that secreted frizzled-related protein 5 (Sfrp5), a protein previously linked to the Wnt signaling pathway, is an anti-inflammatory adipokine whose expression is perturbed in models of obesity and type 2 diabetes. Sfrp5-deficient mice fed a high-calorie diet developed severe glucose intolerance and hepatic steatosis, and their adipose tissue showed an accumulation of activated macrophages that was associated with activation of the c-Jun N-terminal kinase signaling pathway. Adenovirus-mediated delivery of Sfrp5 to mouse models of obesity ameliorated glucose intolerance and hepatic steatosis. Thus, in the setting of obesity, Sfrp5 secretion by adipocytes exerts salutary effects on metabolic dysfunction by controlling inflammatory cells within adipose tissue.

DIP2A functions as a FSTL1 receptor.

FSTL1 is an extracellular glycoprotein whose functional significance in physiological and pathological processes is incompletely understood. Recently, we have shown that FSTL1 acts as a muscle-derived secreted factor that is up-regulated by Akt activation and ischemic stress and that FSTL1 exerts favorable actions on the heart and vasculature. Here, we sought to identify the receptor that mediates the cellular actions of FSTL1. We identified DIP2A as a novel FSTL1-binding partner from the membrane fraction of endothelial cells. Co-immunoprecipitation assays revealed a direct physical interaction between FSTL1 and DIP2A. DIP2A was present on the cell surface of endothelial cells, and knockdown of DIP2A by small interfering RNA reduced the binding of FSTL1 to cells. In cultured endothelial cells, knockdown of DIP2A by small interfering RNA diminished FSTL1-stimulated survival, migration, and differentiation into network structures and inhibited FSTL1-induced Akt phosphorylation. In cultured cardiac myocytes, ablation of DIP2A reduced the protective actions of FSTL1 on hypoxia/reoxygenation-induced apoptosis and suppressed FSTL1-induced Akt phosphorylation. These data indicate that DIP2A functions as a novel receptor that mediates the cardiovascular protective effects of FSTL1.

Activin A and follistatin-like 3 determine the susceptibility of heart to ischemic injury.

BACKGROUND: Transforming growth factor-beta family cytokines have diverse actions in the maintenance of cardiac homeostasis. Activin A is a member of this family whose regulation and function in heart are not well understood at a molecular level. Follistatin-like 3 (Fstl3) is an extracellular regulator of activin A protein, and its function in the heart is also unknown. METHODS AND RESULTS: We analyzed the expression of various transforming growth factor-beta superfamily cytokines and their binding partners in mouse heart. Activin betaA and Fstl3 were upregulated in models of myocardial injury. Overexpression of activin A with an adenoviral vector (Ad-actbetaA) or treatment with recombinant activin A protein protected cultured myocytes from hypoxia/reoxygenation-induced apoptosis. Systemic overexpression of activin A in mice by intravenous injection of Ad-actbetaA protected hearts from ischemia/reperfusion injury. Activin A induced the expression of Bcl-2, and ablation of Bcl-2 by small interfering RNA abrogated its protective action in myocytes. The protective effect of activin A on cultured myocytes was abolished by treatment with Fstl3 or by a pharmacological activin receptor-like kinase inhibitor. Cardiac-specific Fstl3 knockout mice showed significantly smaller infarcts after ischemia/reperfusion injury that was accompanied by reduced apoptosis. CONCLUSIONS: Activin A and Fstl3 are induced in heart by myocardial stress. Activin A protects myocytes from death, and this activity is antagonized by Fstl3. Thus, the relative expression levels of these factors after injury is a determinant of cell survival in the heart.

Follistatin-like 1, a secreted muscle protein, promotes endothelial cell function and revascularization in ischemic tissue through a nitric-oxide synthase-dependent mechanism.

Myogenic Akt signaling coordinates blood vessel recruitment with normal tissue growth. Here, we investigated the role of Follistatin-like 1 (Fstl1) in the regulation of endothelial cell function and blood vessel growth in muscle. Transgenic Akt1 overexpression in skeletal muscle led to myofiber growth that was coupled to an increase in muscle capillary density. Myogenic Akt signaling or ischemic hind limb surgery led to the induction of Fstl1 in muscle and increased circulating levels of Fstl1. Intramuscular administration of an adenoviral vector expressing Fstl1 (Ad-Fstl1) accelerated flow recovery and increased capillary density in the ischemic hind limbs of wild-type mice, and this was associated with an increase in endothelial nitric oxide synthase (eNOS) phosphorylation at residue Ser-1179. In cultured endothelial cells, Ad-Fstl1 stimulated migration and differentiation into network structures and inhibited apoptosis under conditions of serum deprivation. These cell responses were associated with the activating phosphorylation of Akt and eNOS. Conversely, transduction with dominant-negative Akt or LY294002 blocked Fstl1-stimulated eNOS phosphorylation and inhibited Fstl1-stimulated cellular responses. Treatment with the eNOS inhibitor N(G)-nitro-L-arginine methyl ester also reduced endothelial cell migration and differentiation induced by Ad-Fstl1. The stimulatory effect of Ad-Fstl1 on ischemic limb reperfusion was abolished in mice lacking eNOS. These data indicate that Fstl1 is a secreted muscle protein or myokine that can function to promote endothelial cell function and stimulates revascularization in response to ischemic insult through its ability to activate Akt-eNOS signaling.

Follistatin-like 1 is an Akt-regulated cardioprotective factor that is secreted by the heart.

BACKGROUND: The Akt protein kinase is an important mediator of cardiac myocyte growth and survival. To identify factors with novel therapeutic applications in cardiac diseases, we focused on the identification of factors secreted from Akt1-activated cells that have cardioprotective effects through autocrine/paracrine mechanisms. METHODS AND RESULTS: Using an inducible Akt1 transgenic mouse model, we have found that follistatin-like 1 (Fstl1) protein and transcript expression are increased 4.0- and 2.0-fold, respectively, by Akt activation in the heart (P<0.05). Fstl1 transcript was also upregulated in response to myocardial stresses including transverse aortic constriction, ischemia/reperfusion injury, and myocardial infarction. Adenovirus-mediated overexpression of Fstl1 protected cultured neonatal rat ventricular myocytes from hypoxia/reoxygenation-induced apoptosis (P<0.01), and this protective effect was dependent on the upregulation of both Akt and ERK activities. Conversely, knockdown of Fstl1 in cardiac myocytes decreased basal Akt signaling and increased the frequency of apoptotic death in vitro (P<0.01). The intravenous administration of an adenoviral encoding Fstl1 to mice resulted in a 66.0% reduction in myocardial infarct size after ischemia/reperfusion injury that was accompanied by a 70.9% reduction in apoptosis in the heart (P<0.01). CONCLUSIONS: These results indicate that Fstl1 is a cardiac-secreted factor that functions as an antiapoptotic protein. Fstl1 could play a role in myocardial maintenance and repair in response to harmful stimuli.

Identification of cardiac myocytes as the target of interleukin 11, a cardioprotective cytokine.

Interleukin (IL)-6 family cytokines, which share glycoprotein 130 (gp130) as a signal-transducing receptor component, play important roles in the maintenance of cardiac homeostasis. IL-11, a member of IL-6 family cytokines, is expressed in cardiac myocytes, though it remains to be elucidated how IL-11 functions in the hearts. In the present study, first, we showed that IL-11 administration reduced the ischemia/reperfusion injury in the hearts. IL-11 receptor alpha was expressed in cardiomyocytes. IL-11 treatment rapidly activated signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase (ERK) 1/2 in cardiac myocytes. IL-11 stimulation resulted in the translocation of phosphorylated STAT3 into nuclei. Immunofluorescence microscopic analyses revealed that IL-11 treatment led to the cell elongation, as is the case with other cardiotrophic members of IL-6 family, such as leukemia inhibitory factor. Finally we showed that IL-11 treatment conferred the resistance to cell death induced by hydrogen peroxide, which was abrogated by adenoviral transfer of dominant negative STAT3, but not by the inhibition of ERK1/2 with U0126. These findings indicate that IL-11 mediates cytoprotective signals in cardiomyocytes, proposing that IL-11 has the potential to exhibit cardioprotection as a novel biological function.

Microarray analysis of Akt1 activation in transgenic mouse hearts reveals transcript expression profiles associated with compensatory hypertrophy and failure.

To investigate molecular mechanisms involved in the development of cardiac hypertrophy and heart failure, we developed a tetracycline-regulated transgenic system to conditionally switch a constitutively active form of the Akt1 protein kinase on or off in the adult heart. Short-term activation (2 wk) of Akt1 resulted in completely reversible hypertrophy with maintained contractility. In contrast, chronic Akt1 activation (6 wk) induced extensive cardiac hypertrophy, severe contractile dysfunction, and massive interstitial fibrosis. The focus of this study was to create a transcript expression profile of the heart as it undergoes reversible Akt1-mediated hypertrophy and during the transition from compensated hypertrophy to heart failure. Heart tissue was analyzed before transgene induction, 2 wk after transgene induction, 2 wk of transgene induction followed by 2 days of repression, 6 wk after transgene induction, and 6 wk of transgene induction followed by 2 wk of repression. Acute overexpression of Akt1 (2 wk) leads to changes in the expression of 826 transcripts relative to noninduced hearts, whereas chronic induction (6 wk) led to changes in the expression of 1,611, of which 65% represented transcripts that were regulated during the pathological phase of heart growth. Another set of genes identified was uniquely regulated during heart regression but not growth, indicating that nonoverlapping transcription programs participate in the processes of cardiac hypertrophy and atrophy. These data define the gene regulatory programs downstream of Akt that control heart size and contribute to the transition from compensatory hypertrophy to heart failure.

Sildenafil as adjunct therapy to high-dose epoprostenol in a patient with pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease is refractory to medical treatment and is generally associated with a poor prognosis. Treatment with vasodilators, such as prostacyclin, of patients with PVOD is controversial because of concerns regarding hemodynamic deterioration. Although a preferential pulmonary vasodilatory effect of a specific phosphodiesterase-5 inhibitor, sildenafil, has recently been reported in patients with primary pulmonary hypertension, little information is available regarding the effect of sildenafil on patients with pulmonary veno-occlusive disease. In the present case, remarkable improvement of hemodynamics and of clinical course was produced by adjunctive use of oral sildenafil in association with intravenous high-dose epoprostenol. These findings suggest that sildenafil may be a therapeutic option in the medical treatment of pulmonary veno-occlusive disease.

Leukemia inhibitory factor induces endothelial differentiation in cardiac stem cells.

The importance of interleukin 6 (IL-6)-related cytokines in cardiac homeostasis has been studied extensively; however, little is known about their biological significance in cardiac stem cells. Here we describe that leukemia inhibitory factor (LIF), a member of IL-6-related cytokines, activated STAT3 and ERK1/2 in cardiac Sca-1+ stem cells. LIF stimulation resulted in the induction of endothelial cell-specific genes, including VE-cadherin, Flk-1, and CD31, whereas neither smooth muscle nor cardiac muscle marker genes such as GATA4, GATA6, Nkx-2.5, and calponin were up-regulated. Immunocytochemical examination showed that about 25% of total cells were positively stained with anti-CD31 antibody 14 days after LIF stimulation. Immunofluorescent microscopic analyses identified the Sca-1+ cells that were also positively stained with anti-von Willebrand factor antibody, indicating the differentiating process of Sca-1+ cells into the endothelial cells. IL-6, which did not activate STAT3 and ERK1/2, failed to induce the differentiation of cardiac stem cells into the endothelial cells. In cardiac stem cells, the transduction with dominant negative STAT3 abrogated the LIF-induced endothelial differentiation. And the inhibition of ERK1/2 with the MEK1/2 inhibitor U0126 also prevented the differentiation of Sca-1+ cells into endothelial cells. Thus, both STAT3 and ERK1/2 are required for LIF-mediated endothelial differentiation in cardiac stem cells. Collectively, it is proposed that LIF regulates the commitment of cardiac stem cells into the endothelial cell lineage, contributing to neovascularization in the process of tissue remodeling and/or regeneration.

Smad1 protects cardiomyocytes from ischemia-reperfusion injury.

BACKGROUND: We previously reported that bone morphogenetic protein 2 (BMP2) protected against apoptosis of serum-deprived cardiomyocytes via induction of Bcl-xL through the Smad1 pathway. To investigate whether Smad1 signaling promotes cell survival in the adult heart, we subjected transgenic mice with cardiac-specific overexpression of smad1 gene (Smad1TG) to ischemia-reperfusion (I/R) injury. METHODS AND RESULTS: The effects of BMP2 or adenovirus-mediated transfection of smad1 on cardiomyocyte survival in hypoxia-reoxygenation were examined using rat neonatal cardiomyocytes. BMP2 and Smad1 each significantly promoted survival and diminished apoptotic death of cardiomyocytes during hypoxia-reoxygenation. Interestingly, Smad1 was found to be activated during I/R in normal mouse heart. To examine physiological and pathological roles of Smad1 in I/R, we generated Smad1TG using the alpha-myosin heavy chain gene promoter. Phosphorylation of Smad1 was found in all smad1 transgene-positive mouse hearts. To examine whether Smad1 prevents injury of cardiomyocytes in vivo, we subjected Smad1TG and age-matched wild-type mice (WT) to I/R injury induced by 1 hour of ligation of the left coronary artery and 1 hour of reperfusion. TUNEL and DNA ladder analyses showed that Smad1TG had significantly smaller myocardial infarctions and fewer apoptotic deaths of cardiomyocytes than did WT. Interestingly, increased expression of Bcl-xL and beta-catenin was more remarkable whereas caspase3 was less activated in Smad1TG heart than in that of WT. CONCLUSIONS: These findings suggest that the Smad1 signaling pathway plays a role in cardioprotection against I/R injury.

STAT3 mediates cardioprotection against ischemia/reperfusion injury through metallothionein induction in the heart.

OBJECTIVE: Activation of signal transducer and activator of transcription 3 (STAT3) was reported to be correlated with myocardial protection against ischemia/reperfusion (I/R) injury in ischemic preconditioning. Here, we tested the causality between STAT3 activity and cardioprotection. We also addressed the molecular mechanism for its cardioprotection. METHODS AND RESULTS: Cardiac-specific transgenic mice expressing constitutively active STAT3 (TG) were generated and exposed to I/R injury. TG hearts exhibited infarcts that reduced by 60.3% in size, compared with nontransgenic littermates (NTG). By measuring dichlorofluorescein (DCF) and 8-isoprostane, reactive-oxygen-species (ROS)-induced metabolites, it was revealed that ROS were generated to lesser extent in TG hearts than in NTG in response to I/R stress. In parallel, ROS scavengers, metallothionein1 (MT1), and metallothionein2 (MT2) were markedly up-regulated in TG hearts. Finally, homozygous deletion of the MT1 and MT2 genes abrogated cardioprotective effect of STAT3 against I/R injury with the cancellation of its ROS-scavenging effects. CONCLUSIONS: Activation of STAT3 protects myocardium from I/R injury in vivo. STAT3 mediates cardioprotection at least partially through MT1 and 2. STAT3 is a potential therapeutic target for I/R injury.

Circulating interleukin-6 family cytokines and their receptors in patients with congestive heart failure.

gp130 is a common signal-transducing receptor subunit for the interleukin (IL)-6 cytokine family. Studies in genetically engineered animal models have demonstrated a critical role for the gp130-dependent cardiomyocyte survival pathway in the transition to heart failure. In the present study, we examined plasma levels of the IL-6 family of cytokines and the soluble form of their receptors in patients with congestive heart failure (CHF). Circulating levels of the IL-6 family of cytokines, soluble IL-6 receptor (sIL-6R), and soluble gp130 (sgp130) were examined in 48 patients with various degrees of CHF, including dilated cardiomyopathy (DCM), ischemic cardiomyopathy (ICM), and valvular cardiomyopathy (VCM). Circulating levels of IL-6, leukemia inhibitory factor (LIF), and sgp130 significantly increased in association with the severity of CHF. No significant difference was observed in the circulating levels of sIL-6R and IL-11 among these patients. Interestingly, DCM patients showed higher circulating sgp130 levels than patients with ICM or VCM. Our findings suggest that gp130 expression in the heart is likely to be dynamic, and that the IL-6 family of cytokines and their common receptor gp130 participates in the pathogenesis of CHF, especially in DCM.

Signals through gp130 upregulate Wnt5a and contribute to cell adhesion in cardiac myocytes.

Glycoprotein 130 (gp130), a common receptor of IL-6 family cytokines, plays critical roles in cardiac functions. Here, we demonstrate that the stimulation of gp130 with leukemia inhibitory factor (LIF) promoted cell adhesion in a cadherin-dependent manner in cultured cardiomyocytes. Wnt5a was upregulated by the stimulation of gp130 with IL-6 family cytokines, accompanied by N-cadherin protein upregulation. Wnt5a was not induced by LIF in cardiomyocytes expressing dominant-negative STAT3. Ablation of Wnt5a by antisense cDNA inhibited LIF-induced cell adhesion. Collectively, signals through gp130 upregulate Wnt5a through STAT3, promoting the N-cadherin-mediated cell adhesion.

Novel insertional mutation in the bone morphogenetic protein receptor type II associated with sporadic primary pulmonary hypertension.

Primary pulmonary hypertension (PPH), which results from occlusion of small pulmonary arteries, is a devastating condition. Mutations of the bone morphogenetic protein receptor type II gene (BMPR2), a component of the transforming growth factor- beta (TGF-beta) family, which plays a key role in cell growth, have recently been identified as causing familial and sporadic PPH. The first case of BMPR2 mutation found in Japan is reported here in a 19-year-old woman with a clinical diagnosis of PPH and no identifiable family history of pulmonary hypertension. Direct sequencing of the entire coding region and intron/exon boundaries of BMPR2 revealed a frameshift mutation predicted to alter the cell signaling response to specific ligands. A molecular classification of PPH, based upon the presence or absence of BMPR2 mutations, might have important implications for patient management and screening of relatives.

Solitary right ventricle metastasis by renal cell carcinoma.

A 57-year-old man with a history of renal cell carcinoma presented with presyncope. He underwent nephrectomy years earlier followed by HLA-matched allogeneic peripheral-blood stem-cell transplantation. Echocardiographic investigation revealed a solitary right ventricle mass without contiguous vena caval or right atrial involvement. The mass was pathologically confirmed to be metastatic carcinoma in the right ventricular cavity. This case highlights the need to consider an underlying neoplastic syndrome in patients presenting isolated right ventricle mass by echocardiography.