Shortage of autologous blood vessel sources and disadvantages of synthetic grafts have increased ... more Shortage of autologous blood vessel sources and disadvantages of synthetic grafts have increased interest in the development of tissue-engineered vascular grafts. However, tunica media, which comprises layered elastic laminae, largely determines arterial elasticity, and is difficult to synthesize. Here, we describe a method for fabrication of arterial grafts with elastic layer structure from cultured human vascular SMCs by periodic exposure to extremely high hydrostatic pressure (HP) during repeated cell seeding. Repeated slow cycles (0.002 Hz) between 110 and 180 kPa increased stress-fiber polymerization and fibronectin fibrillogenesis on SMCs, which is required for elastic fiber formation. To fabricate arterial grafts, seeding of rat vascular SMCs and exposure to the periodic HP were repeated alternatively ten times. The obtained medial grafts were highly elastic and tensile rupture strength was 1451 ± 159 mmHg, in which elastic fibers were abundantly formed. The patch medial grafts were sutured at the rat aorta and found to be completely patent and endothelialized after 2.5 months, although tubular medial constructs implanted in rats as interpositional aortic grafts withstood arterial blood pressure only in early acute phase. This novel organized self-assembly method would enable mass production of scaffold-free arterial grafts in vitro and have potential therapeutic applications for cardiovascular diseases.
In heart failure patients, chronic hyperactivation of sympathetic signaling is known to exacerbat... more In heart failure patients, chronic hyperactivation of sympathetic signaling is known to exacerbate cardiac dysfunction. In this study, the cardioprotective effect of vidarabine, an anti-herpes virus agent, which we identified as a cardiac adenylyl cyclase inhibitor, in dogs with pacing-induced dilated cardiomyopathy (DCM) was evaluated. In addition, the adverse effects of vidarabine on basal cardiac function was compared to those of the β-blocker, carvedilol.Methods and Results:Vidarabine and carvedilol attenuated the development of pacing-induced systolic dysfunction significantly and with equal effectiveness. Both agents also inhibited the development of cardiac apoptosis and fibrosis and reduced the Na(+)-Ca(2+)exchanger-1 protein level in the heart. Importantly, carvedilol significantly enlarged the left ventricle and atrium; vidarabine, in contrast, did not. Vidarabine-treated dogs maintained cardiac response to β-AR stimulation better than carvedilol-treated dogs did. Vidarabine may protect against pacing-induced DCM with less suppression of basal cardiac function than carvedilol in a dog model. (Circ J 2016; 80: 2496-2505).
Nanoparticulate agents for magnetic drug delivery systems (DDSs) have extensive applications in t... more Nanoparticulate agents for magnetic drug delivery systems (DDSs) have extensive applications in targeted drug delivery, contrast imaging and therapeutics. However, no simple synthetic method for magnetic DDS agents has been developed without the need to add magnetic nanoparticles. Here, we describe the one-step fabrication of 'all-in-one' magneto-assemblies using an 'inorganic-metal-salt-free' method, involving spontaneous self-assembly of the water-insoluble prodrug μ-oxo-bis(N,N 0-ethylenebis (salicylideniminato)iron) [Fe(salen)] (magnetic core) with polypyrrole (PPy)-b-polycaprolactone (PCL) smart diblock copolymers. In the system, PCL serves as a heat-responsive core scaffold, and PPy serves as an electronic core-size controller and pH-responsive shell. This core–shell nanocomposite has a high-loading capacity (~90%), and the core size is tunable by incorporating albumin or gum arabic as bio-coating agents, which also provide colloidal stability, biocompatibility and thermo-stability. Fe(salen), which has intrinsic antitumor activity, also has ubiquitous magnetic properties, which are dramatically enhanced in these molecular assemblies with magnetic coupling. Moreover, these multifunctional nanoassemblies can be delivered magnetically, can serve as magnetic resonance imaging contrast agents, can generate magneto-hyperthermal effects and can enable magnetic field-triggered release of Fe(salen) molecules under acidic conditions.
As one of the most important second messengers, 3',5&... more As one of the most important second messengers, 3',5'-cyclic adenosine monophosphate (cAMP) mediates various extracellular signals including hormones and neurotransmitters, and induces appropriate responses in diverse types of cells. Since cAMP was formerly believed to transmit signals through only two direct target molecules, protein kinase A and the cyclic nucleotide-gated channel, the sensational discovery in 1998 of another novel direct effecter of cAMP [exchange proteins directly activated by cAMP (Epac)] attracted a great deal of scientific interest in cAMP signaling. Numerous studies on Epac have since disclosed its important functions in various tissues in the body. Recently, observations of genetically manipulated mice in various pathogenic models have begun to reveal the in vivo significance of previous in vitro or cellular-level findings. Here, we focused on the function of Epac in the heart. Accumulating evidence has revealed that both Epac1 and Epac2 play important roles in the structure and function of the heart under physiological and pathological conditions. Accordingly, developing the ability to regulate cAMP-mediated signaling through Epac may lead to remarkable new therapies for the treatment of cardiac diseases.
The journal of physiological sciences : JPS, Jan 19, 2016
Pro-inflammatory cytokines are released in septic shock and impair cardiac function via the Jak-S... more Pro-inflammatory cytokines are released in septic shock and impair cardiac function via the Jak-STAT pathway. It is well known that sympathetic and thus catecholamine signaling is activated thereafter to compensate for cardiac dysfunction. The mechanism of such compensation by catecholamine signaling has been traditionally understood to be cyclic AMP-dependent protein kinase (PKA)-mediated enforcement of cardiac contractility. We hypothesized that the exchange protein activated by cAMP (Epac), a newly identified target of cAMP signaling that functions independently of PKA, also plays a key role in this mechanism. In cultured cardiac myocytes, activation of Epac attenuated the inhibitory effect of interleukin-6 on the increase of intracellular Ca(2+) concentration and contractility in response to isoproterenol, most likely through inhibition of the Jak-STAT pathway via SOCS3, with subsequent changes in inducible nitric oxide synthase expression. These findings suggest a new role of c...
Circulation journal : official journal of the Japanese Circulation Society, Jan 21, 2016
Extremely preterm infants frequently have patent ductus arteriosus (PDA). Recent recommendations ... more Extremely preterm infants frequently have patent ductus arteriosus (PDA). Recent recommendations include immediately beginning amino acid supplementation in extremely preterm infants. However, the effect of amino acids on closure of the ductus arteriosus (DA) remains unknown.Methods and Results:Aminogram results in human neonates at day 2 revealed that the plasma glutamate concentration was significantly lower in extremely preterm infants (<28 weeks' gestation) with PDA than in those without PDA and relatively mature preterm infants (28-29 weeks gestation). To investigate the effect of glutamate on DA closure, glutamate receptor expression in fetal rats was examined and it was found that the glutamate inotropic receptor, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type subunit 1 (GluR1), mRNA was highly expressed in the DA compared to the aorta on gestational day 19 (preterm) and gestational day 21 (term). GluR1 proteins were co-localized with tyrosine hydroxylase...
Melanoma has an extremely poor prognosis due to its rapidly progressive and highly metastatic nat... more Melanoma has an extremely poor prognosis due to its rapidly progressive and highly metastatic nature. Several therapeutic drugs have recently become available, but are effective only against melanoma with specific BRAF gene mutation. Thus, there is a need to identify other target molecules. We show here that Transient receptor potential, canonical 3 (TRPC3) is widely expressed in human melanoma. We found that pharmacological inhibition of TRPC3 with a pyrazole compound, Pyr3, decreased melanoma cell proliferation and migration. Similar inhibition was observed when the TRPC3 gene was silenced with short-hairpin RNA (shRNA). Pyr3 induced dephosphorylation of signal transducer and activator of transcription (STAT) 5 and Akt. Administration of Pyr3 (0.05 mg/kg) to mice implanted with human melanoma cells (C8161) significantly inhibited tumor growth. Our findings indicate that TRPC3 plays an important role in melanoma growth, and may be a novel target for treating melanoma in patients.
Biochemical and Biophysical Research Communications, Sep 1, 2009
Epithelial sodium channels (ENaC) located along the aldosterone-sensitive distal nephron (ASDN) p... more Epithelial sodium channels (ENaC) located along the aldosterone-sensitive distal nephron (ASDN) play a pivotal role in the homeostasis of sodium balance. Among various modulating proteins, E3 ubiquitin ligase, Nedd4L, binds the PY motif of ENaC COOH terminals and catalyzes ubiquitination of the NH(2) terminal of the protein for subsequent degradation. One of the isoforms of human Nedd4L with evolutionarily new C2 domain was reported to play a significant role for degradating cell surface ENaC with interfering with wild isoforms by us previously. We focused the current analyses on isolating the binding molecules with C2 domain using yeast two-hybrid screening to elucidate further molecular interactions between ENaC and Nedd4L. We found NPC2, also known as HE-1, bind C2 domain of human Nedd4L and express along ASDN colocalized with Nedd4L. Additionally, in experiments using a model of salt-sensitive hypertension in Dahl rats, we provided evidence suggesting that transcriptional regulation and activation of NPC2 protein depends on sodium intake. NPC2 might regulate sodium reabsorption in the terminal nephron by interacting with ENaC-Nedd4L system.
Biochemical and biophysical research communications, Jan 23, 2016
Type 5 adenylyl cyclase (AC5) plays an important role in the development of chronic catecholamine... more Type 5 adenylyl cyclase (AC5) plays an important role in the development of chronic catecholamine stress-induced heart failure and arrhythmia in mice. Epac (exchange protein activated by cAMP), which is directly activated by cAMP independent of protein kinase A, has been recently identified as a novel mediator of cAMP signaling in the heart. However, the role of Epac in AC5-mediated cardiac dysfunction and arrhythmias remains poorly understood. We therefore generated AC5 transgenic mice (AC5TG) with selective disruption of the Epac1 gene (AC5TG-Epac1KO), and compared their phenotypes with those of AC5TG after chronic isoproterenol (ISO) infusion. Decreased cardiac function as well as increased susceptibility to pacing-induced atrial fibrillation (AF) in response to ISO were significantly attenuated in AC5TG-Epac1KO mice, compared to AC5TG mice. Increased cardiac apoptosis and cardiac fibrosis were also concomitantly attenuated in AC5TG-Epac1KO mice compared to AC5TG mice. These find...
We previously investigated the utility of μ-oxo N,N′-bis(salicylidene)ethylenediamine iron (Fe(Sa... more We previously investigated the utility of μ-oxo N,N′-bis(salicylidene)ethylenediamine iron (Fe(Salen)) nanoparticles as a new anti-cancer agent for magnet-guided delivery with anti-cancer activity. Fe(Salen) nanoparticles should rapidly heat up in an alternating magnetic field (AMF), and we hypothesized that these single-drug nanoparticles would be effective for combined hyperthermia-chemotherapy. Conventional hyperthermic particles are usually made of iron oxide, and thus cannot exhibit anti-cancer activity in the absence of an AMF. We found that Fe(Salen) nanoparticles induced apoptosis in cultured cancer cells, and that AMF exposure enhanced the apoptotic effect. Therefore, we evaluated the combined threefold strategy, i.e., chemotherapy with Fe(Salen) nanoparticles, magnetically guided delivery of the nanoparticles to the tumor, and AMF-induced heating of the nanoparticles to induce local hyperthermia, in a rabbit model of tongue cancer. Intravenous administration of Fe(Salen) nanoparticles per se inhibited tumor growth before the other two modalities were applied. This inhibition was enhanced when a magnet was used to accumulate Fe(Salen) nanoparticles at the tongue. When an AMF was further applied (magnet-guided chemotherapy plus hyperthermia), the tumor masses were dramatically reduced. These results indicate that our strategy of combined hyperthermia-chemotherapy using Fe(Salen) nanoparticles specifically delivered with magnetic guidance represents a powerful new approach for cancer treatment. Head and neck cancer is the sixth most common cancer, accounting for 3% of all cancers worldwide. The incidence of new patients is increasing, particularly in developing countries 1,2. Tumors are located in the oral cavity in 48% of cases, and 90% of these are oral squamous cell carcinoma. Oral malignancy, including tongue cancer, is associated with severe morbidity and has a long-term survival of less than 50%, in spite of advances in the treatment of oral cancer by surgery, chemotherapy, and radiation. The survival ratio of patients remains very low, mainly due to lymph node metastasis 2. Surgical removal of the cancer tissues is the gold standard, but involves various complications, such as dysphagia or dysarthria. Therefore, more effective treatment for oral cancer, with fewer complications, needs to be developed.
Net sodium balances in humans are maintained through various ion transporters expressed along the... more Net sodium balances in humans are maintained through various ion transporters expressed along the entire nephron. Among these ion transporters, epithelial sodium channels (ENaC) located along the aldosterone-sensitive distal nephron (ASDN) play a pivotal role in the homeostasis of sodium balance. This is supported by analyses of inherited hypertensive disorders, showing that genes encoding ENaC and other modulatory proteins cause
Shortage of autologous blood vessel sources and disadvantages of synthetic grafts have increased ... more Shortage of autologous blood vessel sources and disadvantages of synthetic grafts have increased interest in the development of tissue-engineered vascular grafts. However, tunica media, which comprises layered elastic laminae, largely determines arterial elasticity, and is difficult to synthesize. Here, we describe a method for fabrication of arterial grafts with elastic layer structure from cultured human vascular SMCs by periodic exposure to extremely high hydrostatic pressure (HP) during repeated cell seeding. Repeated slow cycles (0.002 Hz) between 110 and 180 kPa increased stress-fiber polymerization and fibronectin fibrillogenesis on SMCs, which is required for elastic fiber formation. To fabricate arterial grafts, seeding of rat vascular SMCs and exposure to the periodic HP were repeated alternatively ten times. The obtained medial grafts were highly elastic and tensile rupture strength was 1451 ± 159 mmHg, in which elastic fibers were abundantly formed. The patch medial grafts were sutured at the rat aorta and found to be completely patent and endothelialized after 2.5 months, although tubular medial constructs implanted in rats as interpositional aortic grafts withstood arterial blood pressure only in early acute phase. This novel organized self-assembly method would enable mass production of scaffold-free arterial grafts in vitro and have potential therapeutic applications for cardiovascular diseases.
In heart failure patients, chronic hyperactivation of sympathetic signaling is known to exacerbat... more In heart failure patients, chronic hyperactivation of sympathetic signaling is known to exacerbate cardiac dysfunction. In this study, the cardioprotective effect of vidarabine, an anti-herpes virus agent, which we identified as a cardiac adenylyl cyclase inhibitor, in dogs with pacing-induced dilated cardiomyopathy (DCM) was evaluated. In addition, the adverse effects of vidarabine on basal cardiac function was compared to those of the β-blocker, carvedilol.Methods and Results:Vidarabine and carvedilol attenuated the development of pacing-induced systolic dysfunction significantly and with equal effectiveness. Both agents also inhibited the development of cardiac apoptosis and fibrosis and reduced the Na(+)-Ca(2+)exchanger-1 protein level in the heart. Importantly, carvedilol significantly enlarged the left ventricle and atrium; vidarabine, in contrast, did not. Vidarabine-treated dogs maintained cardiac response to β-AR stimulation better than carvedilol-treated dogs did. Vidarabine may protect against pacing-induced DCM with less suppression of basal cardiac function than carvedilol in a dog model. (Circ J 2016; 80: 2496-2505).
Nanoparticulate agents for magnetic drug delivery systems (DDSs) have extensive applications in t... more Nanoparticulate agents for magnetic drug delivery systems (DDSs) have extensive applications in targeted drug delivery, contrast imaging and therapeutics. However, no simple synthetic method for magnetic DDS agents has been developed without the need to add magnetic nanoparticles. Here, we describe the one-step fabrication of 'all-in-one' magneto-assemblies using an 'inorganic-metal-salt-free' method, involving spontaneous self-assembly of the water-insoluble prodrug μ-oxo-bis(N,N 0-ethylenebis (salicylideniminato)iron) [Fe(salen)] (magnetic core) with polypyrrole (PPy)-b-polycaprolactone (PCL) smart diblock copolymers. In the system, PCL serves as a heat-responsive core scaffold, and PPy serves as an electronic core-size controller and pH-responsive shell. This core–shell nanocomposite has a high-loading capacity (~90%), and the core size is tunable by incorporating albumin or gum arabic as bio-coating agents, which also provide colloidal stability, biocompatibility and thermo-stability. Fe(salen), which has intrinsic antitumor activity, also has ubiquitous magnetic properties, which are dramatically enhanced in these molecular assemblies with magnetic coupling. Moreover, these multifunctional nanoassemblies can be delivered magnetically, can serve as magnetic resonance imaging contrast agents, can generate magneto-hyperthermal effects and can enable magnetic field-triggered release of Fe(salen) molecules under acidic conditions.
As one of the most important second messengers, 3&amp;amp;amp;amp;amp;amp;#39;,5&amp;amp;... more As one of the most important second messengers, 3&amp;amp;amp;amp;amp;amp;#39;,5&amp;amp;amp;amp;amp;amp;#39;-cyclic adenosine monophosphate (cAMP) mediates various extracellular signals including hormones and neurotransmitters, and induces appropriate responses in diverse types of cells. Since cAMP was formerly believed to transmit signals through only two direct target molecules, protein kinase A and the cyclic nucleotide-gated channel, the sensational discovery in 1998 of another novel direct effecter of cAMP [exchange proteins directly activated by cAMP (Epac)] attracted a great deal of scientific interest in cAMP signaling. Numerous studies on Epac have since disclosed its important functions in various tissues in the body. Recently, observations of genetically manipulated mice in various pathogenic models have begun to reveal the in vivo significance of previous in vitro or cellular-level findings. Here, we focused on the function of Epac in the heart. Accumulating evidence has revealed that both Epac1 and Epac2 play important roles in the structure and function of the heart under physiological and pathological conditions. Accordingly, developing the ability to regulate cAMP-mediated signaling through Epac may lead to remarkable new therapies for the treatment of cardiac diseases.
The journal of physiological sciences : JPS, Jan 19, 2016
Pro-inflammatory cytokines are released in septic shock and impair cardiac function via the Jak-S... more Pro-inflammatory cytokines are released in septic shock and impair cardiac function via the Jak-STAT pathway. It is well known that sympathetic and thus catecholamine signaling is activated thereafter to compensate for cardiac dysfunction. The mechanism of such compensation by catecholamine signaling has been traditionally understood to be cyclic AMP-dependent protein kinase (PKA)-mediated enforcement of cardiac contractility. We hypothesized that the exchange protein activated by cAMP (Epac), a newly identified target of cAMP signaling that functions independently of PKA, also plays a key role in this mechanism. In cultured cardiac myocytes, activation of Epac attenuated the inhibitory effect of interleukin-6 on the increase of intracellular Ca(2+) concentration and contractility in response to isoproterenol, most likely through inhibition of the Jak-STAT pathway via SOCS3, with subsequent changes in inducible nitric oxide synthase expression. These findings suggest a new role of c...
Circulation journal : official journal of the Japanese Circulation Society, Jan 21, 2016
Extremely preterm infants frequently have patent ductus arteriosus (PDA). Recent recommendations ... more Extremely preterm infants frequently have patent ductus arteriosus (PDA). Recent recommendations include immediately beginning amino acid supplementation in extremely preterm infants. However, the effect of amino acids on closure of the ductus arteriosus (DA) remains unknown.Methods and Results:Aminogram results in human neonates at day 2 revealed that the plasma glutamate concentration was significantly lower in extremely preterm infants (<28 weeks' gestation) with PDA than in those without PDA and relatively mature preterm infants (28-29 weeks gestation). To investigate the effect of glutamate on DA closure, glutamate receptor expression in fetal rats was examined and it was found that the glutamate inotropic receptor, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type subunit 1 (GluR1), mRNA was highly expressed in the DA compared to the aorta on gestational day 19 (preterm) and gestational day 21 (term). GluR1 proteins were co-localized with tyrosine hydroxylase...
Melanoma has an extremely poor prognosis due to its rapidly progressive and highly metastatic nat... more Melanoma has an extremely poor prognosis due to its rapidly progressive and highly metastatic nature. Several therapeutic drugs have recently become available, but are effective only against melanoma with specific BRAF gene mutation. Thus, there is a need to identify other target molecules. We show here that Transient receptor potential, canonical 3 (TRPC3) is widely expressed in human melanoma. We found that pharmacological inhibition of TRPC3 with a pyrazole compound, Pyr3, decreased melanoma cell proliferation and migration. Similar inhibition was observed when the TRPC3 gene was silenced with short-hairpin RNA (shRNA). Pyr3 induced dephosphorylation of signal transducer and activator of transcription (STAT) 5 and Akt. Administration of Pyr3 (0.05 mg/kg) to mice implanted with human melanoma cells (C8161) significantly inhibited tumor growth. Our findings indicate that TRPC3 plays an important role in melanoma growth, and may be a novel target for treating melanoma in patients.
Biochemical and Biophysical Research Communications, Sep 1, 2009
Epithelial sodium channels (ENaC) located along the aldosterone-sensitive distal nephron (ASDN) p... more Epithelial sodium channels (ENaC) located along the aldosterone-sensitive distal nephron (ASDN) play a pivotal role in the homeostasis of sodium balance. Among various modulating proteins, E3 ubiquitin ligase, Nedd4L, binds the PY motif of ENaC COOH terminals and catalyzes ubiquitination of the NH(2) terminal of the protein for subsequent degradation. One of the isoforms of human Nedd4L with evolutionarily new C2 domain was reported to play a significant role for degradating cell surface ENaC with interfering with wild isoforms by us previously. We focused the current analyses on isolating the binding molecules with C2 domain using yeast two-hybrid screening to elucidate further molecular interactions between ENaC and Nedd4L. We found NPC2, also known as HE-1, bind C2 domain of human Nedd4L and express along ASDN colocalized with Nedd4L. Additionally, in experiments using a model of salt-sensitive hypertension in Dahl rats, we provided evidence suggesting that transcriptional regulation and activation of NPC2 protein depends on sodium intake. NPC2 might regulate sodium reabsorption in the terminal nephron by interacting with ENaC-Nedd4L system.
Biochemical and biophysical research communications, Jan 23, 2016
Type 5 adenylyl cyclase (AC5) plays an important role in the development of chronic catecholamine... more Type 5 adenylyl cyclase (AC5) plays an important role in the development of chronic catecholamine stress-induced heart failure and arrhythmia in mice. Epac (exchange protein activated by cAMP), which is directly activated by cAMP independent of protein kinase A, has been recently identified as a novel mediator of cAMP signaling in the heart. However, the role of Epac in AC5-mediated cardiac dysfunction and arrhythmias remains poorly understood. We therefore generated AC5 transgenic mice (AC5TG) with selective disruption of the Epac1 gene (AC5TG-Epac1KO), and compared their phenotypes with those of AC5TG after chronic isoproterenol (ISO) infusion. Decreased cardiac function as well as increased susceptibility to pacing-induced atrial fibrillation (AF) in response to ISO were significantly attenuated in AC5TG-Epac1KO mice, compared to AC5TG mice. Increased cardiac apoptosis and cardiac fibrosis were also concomitantly attenuated in AC5TG-Epac1KO mice compared to AC5TG mice. These find...
We previously investigated the utility of μ-oxo N,N′-bis(salicylidene)ethylenediamine iron (Fe(Sa... more We previously investigated the utility of μ-oxo N,N′-bis(salicylidene)ethylenediamine iron (Fe(Salen)) nanoparticles as a new anti-cancer agent for magnet-guided delivery with anti-cancer activity. Fe(Salen) nanoparticles should rapidly heat up in an alternating magnetic field (AMF), and we hypothesized that these single-drug nanoparticles would be effective for combined hyperthermia-chemotherapy. Conventional hyperthermic particles are usually made of iron oxide, and thus cannot exhibit anti-cancer activity in the absence of an AMF. We found that Fe(Salen) nanoparticles induced apoptosis in cultured cancer cells, and that AMF exposure enhanced the apoptotic effect. Therefore, we evaluated the combined threefold strategy, i.e., chemotherapy with Fe(Salen) nanoparticles, magnetically guided delivery of the nanoparticles to the tumor, and AMF-induced heating of the nanoparticles to induce local hyperthermia, in a rabbit model of tongue cancer. Intravenous administration of Fe(Salen) nanoparticles per se inhibited tumor growth before the other two modalities were applied. This inhibition was enhanced when a magnet was used to accumulate Fe(Salen) nanoparticles at the tongue. When an AMF was further applied (magnet-guided chemotherapy plus hyperthermia), the tumor masses were dramatically reduced. These results indicate that our strategy of combined hyperthermia-chemotherapy using Fe(Salen) nanoparticles specifically delivered with magnetic guidance represents a powerful new approach for cancer treatment. Head and neck cancer is the sixth most common cancer, accounting for 3% of all cancers worldwide. The incidence of new patients is increasing, particularly in developing countries 1,2. Tumors are located in the oral cavity in 48% of cases, and 90% of these are oral squamous cell carcinoma. Oral malignancy, including tongue cancer, is associated with severe morbidity and has a long-term survival of less than 50%, in spite of advances in the treatment of oral cancer by surgery, chemotherapy, and radiation. The survival ratio of patients remains very low, mainly due to lymph node metastasis 2. Surgical removal of the cancer tissues is the gold standard, but involves various complications, such as dysphagia or dysarthria. Therefore, more effective treatment for oral cancer, with fewer complications, needs to be developed.
Net sodium balances in humans are maintained through various ion transporters expressed along the... more Net sodium balances in humans are maintained through various ion transporters expressed along the entire nephron. Among these ion transporters, epithelial sodium channels (ENaC) located along the aldosterone-sensitive distal nephron (ASDN) play a pivotal role in the homeostasis of sodium balance. This is supported by analyses of inherited hypertensive disorders, showing that genes encoding ENaC and other modulatory proteins cause
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Papers by Masanari Umemura