Hypersensitivity of myelinated A-fibers via toll-like receptor 5 promotes mechanical allodynia in tenascin-X-deficient mice associated with Ehlers-Danlos syndrome

Deficiency of an extracellular matrix glycoprotein tenascin-X (TNX) leads to a human heritable disorder Ehlers-Danlos syndrome, and TNX-deficient patients complain of chronic joint pain, myalgia, paresthesia, and axonal polyneuropathy. We previously reported that TNX-deficient (Tnxb-/-) mice exhibit mechanical allodynia and hypersensitivity to myelinated A-fibers. Here, we investigated the pain response of Tnxb-/- mice using pharmacological silencing of A-fibers with co-injection of N-(2,6-Dimethylphenylcarbamoylmethyl) triethylammonium bromide (QX-314), a membrane-impermeable lidocaine analog, plus flagellin, a toll-like receptor 5 (TLR5) ligand. Intraplantar co-injection of QX-314 and flagellin significantly increased the paw withdrawal threshold to transcutaneous sine wave stimuli at frequencies of 250 Hz (Aδ fiber responses) and 2000 Hz (Aβ fiber responses), but not 5 Hz (C fiber responses) in wild-type mice. The QX-314 plus flagellin-induced silencing of Aδ- and Aβ-fibers was also observed in Tnxb-/- mice. Co-injection of QX-314 and flagellin significantly inhibited the mechanical allodynia and neuronal activation of the spinal dorsal horn in Tnxb-/- mice. Interestingly, QX-314 alone inhibited the mechanical allodynia in Tnxb-/- mice, and it increased the paw withdrawal threshold to stimuli at frequencies of 250 Hz and 2000 Hz in Tnxb-/- mice, but not in wild-type mice. The inhibition of mechanical allodynia induced by QX-314 alone was blocked by intraplantar injection of a TLR5 antagonist TH1020 in Tnxb-/- mice. These results suggest that mechanical allodynia due to TNX deficiency is caused by the hypersensitivity of Aδ- and Aβ-fibers, and it is induced by constitutive activation of TLR5.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Intraosseous carcinoma of the anterior maxilla identified as the occult primary tumour of carcinoma of unknown primary

Carcinoma of unknown primary (CUP) is defined as lymph node metastasis without a detectable origin until after the initial treatment has been performed. The most common occult primary site in the head and neck, as revealed by a review of the published literature, is the oropharynx. An occult primary site in the oral region is extremely rare. We report a rare case of head and neck CUP (HNCUP) in a 69-year-old female patient, wherein the occult primary lesion was a primary intraosseous carcinoma (PIOC) invading the anterior maxilla. During the course of the initial diagnostic workup, no primary lesion could be identified; however, cervical lymph node metastasis to left levels IB and IIA were observed in the patient. A neck dissection followed by adjuvant radiotherapy was performed. However, the PIOC of the anterior maxilla was identified 6 months after neck treatment and was confirmed as the occult primary tumour of the HNCUP. This case is quite rare and required a comprehensive workup to guide optimal treatment. Careful follow-up or active biopsy should be considered if osteolytic changes are observed in the jaw.

Prevalence of and risk factors for depressive symptoms in non-tuberculous mycobacterial pulmonary disease

BACKGROUND: The presence of depressive symptoms in patients with non-tuberculous mycobacterial pulmonary disease (NTM-PD) is an important research topic; however, the prevalence of depressive symptoms and the factors that influence their development are unclear.OBJECTIVE: To analyse the association between CES-D (Center for Epidemiological Studies Depression Scale) scores and clinical parameters such as age, disease duration, pulmonary function, imaging findings, blood data, physical functions, sleep disturbances, respiratory symptoms and health-related quality of life (HRQOL).METHODS: We conducted a cross-sectional retrospective study of 114 patients with NTM-PD at a single centre from March 2016 to January 2021 to evaluate the relationship between CES-D scores and clinical parameters.RESULTS: Participants had a median age of 64 years; 32.5% of them had depressive symptoms. Disease duration, albumin, C-reactive protein, pulmonary function, dyspnoea, exercise capacity, respiratory symptoms, cough-related HRQOL and sleep disturbances were associated with depressive symptoms. Binomial logistic regression analyses indicated that the CES-D score was significantly associated with cough-related HRQOL and sleep disturbances.CONCLUSION: A high percentage of NTM-PD patients in this study experienced depressive symptoms, and these patients had abnormalities of various clinical parameters. Cough-related HRQOL and sleep disturbance had a strong influence on the development of depressive symptoms.

Health-related quality of life associates with clinical parameters in patients with NTM pulmonary disease

BACKGROUND: Previous studies have shown a reduction in health-related quality of life (HRQoL) in patients with non-tuberculous mycobacterial pulmonary disease (NTM-PD). However, the causes of this decline and the factors that contribute to it are unknown. This study was conducted to analyse the association between the St George´s Respiratory Questionnaire (SGRQ) and clinical parameters, including age, disease duration, body composition, pulmonary function, chest X-ray findings, blood data and physical function.METHODS: We performed a single-centre, cross-sectional, retrospective study of 101 patients with NTM-PD from December 2016 to October 2019. The relationship between the SGRQ scores and clinical parameters was evaluated.RESULTS: The median patient age was 67.0 years. Pulmonary function, radiological score, albumin levels, C-reactive protein levels and incremental shuttle walk test distance (ISWD) were significantly correlated with the total and component scores on the SGRQ. Multiple regression analysis showed that the SGRQ score was significantly associated with radiological score, pulmonary function and ISWD.CONCLUSION: This study was the first to assess the effect of clinical parameters on the SGRQ in patients with NTM-PD. HRQoL as determined using the SGRQ was associated with the radiological score, pulmonary function and ISWD in patients with NTM-PD.

Adsorptive granulocyte and monocyte apheresis: A potentially relevant therapeutic option for COVID-19

The overproduction of proinflammatory cytokines and subsequent thromboembolism are major problems of coronavirus disease 2019 (COVID-19). Adsorptive granulocyte and monocyte apheresis (GMA), used for ulcerative colitis, is an extracorporeal therapy designed to remove activated myeloid lineage cells. Previous studies have demonstrated that GMA decreases proinflammatory cytokines and neutrophil-platelet aggregates. The effect of GMA on COVID-19 in a patient with ulcerative colitis was recently reported. The modes of action of GMA together with the findings of this case report indicate that GMA could be a relevant treatment option for COVID-19.

Gas Permeation Property of Silicon Carbide Membranes Synthesized by Counter-Diffusion Chemical Vapor Deposition

An amorphous silicon carbide (SiC) membrane was synthesized by counter-diffusion chemical vapor deposition (CDCVD) using silacyclobutane (SCB) at 788 K. The SiC membrane on a Ni-γ-alumina (Al₂O₃) α-coated Al₂O₃ porous support possessed a H₂ permeance of 1.2 × 10⁻⁷ mol·m⁻²·s⁻¹·Pa⁻¹ and an excellent H₂/CO₂ selectivity of 2600 at 673 K. The intermittent action of H₂ reaction gas supply and vacuum inside porous support was very effective to supply source gas inside mesoporous intermediate layer. A SiC active layer was formed inside the Ni-γ-Al₂O₃ intermediate layer. The thermal expansion coefficient mismatch between the SiC active layer and Ni-γ-Al₂O₃-coated α-Al₂O₃ porous support was eased by the low decomposition temperature of the SiC source and the membrane structure.

Imaging of local structures affecting electrical transport properties of large graphene sheets by lock-in thermography

The distribution of defects and dislocations in graphene layers has become a very important concern with regard to the electrical and electronic transport properties of device applications. Although several experiments have shown the influence of defects on the electrical properties of graphene, these studies were limited to measuring microscopic areas because of their long measurement times. Here, we successfully imaged various local defects in a large area of chemical vapor deposition graphene within a reasonable amount of time by using lock-in thermography (LIT). The differences in electrical resistance caused by the micrometer-scale defects, such as cracks and wrinkles, and atomic-scale domain boundaries were apparent as nonuniform Joule heating on polycrystalline and epitaxially grown graphene. The present results indicate that LIT can serve as a fast and effective method of evaluating the quality and uniformity of large graphene films for device applications.

Interactions between Respiratory, Cardiac and Stepping Rhythms in Decerebrated Cats: Functional Hierarchical Structures of Biological Oscillators

Interactions are described of central origin between respiratory, cardiac and stepping rhythms during fictive locomotion in paralyzed, vagotomized, and decerebrated cats. Fictive locomotion was induced by tonic electrical stimulation of the mesencephalic locomotor region (MLR). The coherence between heart beat fluctuation, the efferent discharges of the phrenic, and the lateral gastrocnemius nerves was used to evaluate the strength of the coupling between those three rhythms. The heart beat rhythm was modulated by the centrally generated respiratory and stepping rhythms. The central respiratory rhythm was modulated by the centrally generated stepping rhythm. Based on the present findings, we have proposed a new model concerning the functional hierarchical structures of the three biological oscillators.

Anandamide induces apoptosis in human endothelial cells: its regulation system and clinical implications

Anandamide (AEA), an endogenous cannabinoid, is generated by macrophages during shock conditions, and is thought to be a causative mediator of septic shock. Thus, we hypothesized that AEA plays a crucial role in endothelial cell (EC) injury. Here, we demonstrate that AEA induces apoptosis in a time-and dose-dependent manner in human umbilical vein endothelial cells (HUVECs). AEA triggered phosphorylation of c-Jun NH2-terminal kinase (JNK) and p38 mitogen activated protein kinase. AEA also showed a marked increase of interleukin 1β–converting enzyme (ICE)CED-3 family protease (caspase-3) activity. AEA-induced EC death was inhibited by a selective vanilloid receptor 1 (VR1) antagonist, capsazepine, and was enhanced by a VR1 agonist, capsaicin, indicating that AEA induces apoptosis in ECs via VR1. In conclusion, we propose that AEA may play a crucial role in EC injury under conditions of shock, and that the use of inhibitors of the AEA regulation system may have a therapeutic effect under these conditions.

Gate-Tunable Spin-Charge Conversion and the Role of Spin-Orbit Interaction in Graphene

The small spin-orbit interaction of carbon atoms in graphene promises a long spin diffusion length and the potential to create a spin field-effect transistor. However, for this reason, graphene was largely overlooked as a possible spin-charge conversion material. We report electric gate tuning of the spin-charge conversion voltage signal in single-layer graphene. Using spin pumping from an yttrium iron garnet ferrimagnetic insulator and ionic liquid top gate, we determined that the inverse spin Hall effect is the dominant spin-charge conversion mechanism in single-layer graphene. From the gate dependence of the electromotive force we showed the dominance of the intrinsic over Rashba spin-orbit interaction, a long-standing question in graphene research.

Upregulation of non-β cell-derived vascular endothelial growth factor A increases small clusters of insulin-producing cells in the pancreas

Pancreatic β cell-derived vascular endothelial growth factor A (VEGF-A) contributes to normal β cell function. We therefore hypothesized that non-β cell-derived VEGF-A may affect its properties in adult mice.We generated transgenic mice expressing human VEGF-A (hVEGF-A) in a visceral smooth muscle cell (SMC)-dominant manner under the control of the transgelin (Tagln/SM22α) promoter via a tamoxifen-induced Cre/loxP recombination system (SM-CreER(T2)/hVEGF mice).SM-CreER(T2)/hVEGF mice received tamoxifen orally followed by microscopic examination of their pancreas 4 weeks after the hVEGF-A induction. The number of clusters of insulin-producing cells (IPCs) in islets, pancreatic ducts, and individual IPCs were counted.The number of small IPC clusters (100-215 μm(2)) in the pancreas increased significantly in SM-CreER(T2)/hVEGF mice compared with SM-CreER(T2)(Ki) mice (473 out of 1 992 counts vs. 199 out of 976 counts, p<0.05), although total IPC area and the number of pancreatic duct IPCs, in proportion to exocrine area, were similar between the 2 groups. Although most small IPC clusters observed in SM-CreER(T2)/hVEGF mice were not accompanied by α and/or δ cells, some were attached to a single or a few α cells. An STZ-induced diabetic state in SM-CreER(T2)/hVEGF mice was slightly ameliorated, with only one point of significance 12 weeks after STZ administration, compared with SM-CreER(T2)(Ki) mice.Upregulation of non-β cell-derived VEGF-A may alter the composition of pancreatic IPCs by increasing the number of small IPC clusters. These findings provide new information on the role of non-β cell-derived VEGF-A to IPC regeneration and insulin production.

Comprehensive safety management and assessment at rugby football competitions

The present study aims to improve medical systems by designing objective safety assessment criteria for rugby competitions. We evaluated 195 competitions between 2002 and 2011 using an original safety scale comprising the following sections: 1) competence of staff such as referees, medical attendants and match day doctor; 2) environment such as weather, wet bulb globe temperature and field conditions; and 3) emergency medical care systems at the competitions. Each section was subdivided into groups A, B and C according to good, normal or fair degrees of safety determined by combinations of the results.Overall safety was assessed as A, B and C for 110, 78 and 7 competitions, respectively. The assessments of individual major factors were mostly favorable for staff, but the environment and medical care systems were assessed as C in 25 and 70, respectively, of the 195 competitions. Medical management involves not having a match day doctor, but also comprehensive management including preventive factors and responses from the staff, environment and medical-care systems. 6 cases of severe injuries and accidents occurred between 2002 and 2011, which were observed in Grade A competition. These cases revealed better prognosis without obvious impairment, thus confirming the value of the present assessment scale.

Effects of pharmacological inhibition of AMP-activated protein kinase on GLUT3 expression and the development of ischemic tolerance in astrocytes

Ischemic tolerance resulting from preconditioning ischemia is a neuroprotective mechanism. In cultured astrocytes, its development depends on regulation of the expression of glucose transporter 3 (GLUT3) by the stress sensor/effector AMP-activated protein kinase (AMPK). Here we demonstrate that GLUT3 is upregulated during preconditioning and then downregulated during recovery. We also found that, although AMPK inhibition during preconditioning initially suppressed the upregulation of GLUT3 as shown previously, this was followed by a period of GLUT3 upregulation, enhanced glycogen accumulation, and enhanced tolerance to a subsequent ischemic challenge. These results reveal that AMPK has a complex influence on ischemic tolerance.

Angiosarcoma of the oral cavity: a clinicopathological study and a review of the literature

Soft tissue sarcomas are uncommon in the head and neck. Primary angiosarcomas of the oral cavity area are extremely rare, and have mostly been presented as case reports. This paper presents the clinical and histological features of three such cases. All patients were diagnosed based on the presence of rapidly extending masses involving the tongue, maxillary gingiva, or mandibular gingiva; bone destruction was present in two cases. The resected specimens revealed clustered large, pleomorphic, and spindle-shaped cells with a markedly haemorrhagic background. Tumour cells showed expression of vascular endothelial markers, such a CD31, CD34, and factor VIII-related antigen. Despite undergoing radical surgery, distant metastases developed in all three cases. We also studied the clinicopathological features of a series of oral angiosarcomas. This article therefore reports the clinicopathological features of the three new cases and provides a review of the cases of primary oral angiosarcoma reported during the past 20 years.

Is the prognostic impact of tumor location in patients with surgically resected esophageal squamous cell carcinoma affected by surgical approach?

AIM

The aim of the present study was to clarify differences in node metastasis mode and clinical outcomes based on tumor location in patients with esophageal squamous cell carcinoma (ESCC).

PATIENTS AND METHODS

Participants comprised 228 patients with ESCC who underwent radical esophagectomy without preoperative supplement therapies. Lymph nodes were harvested from three fields: the neck, thorax, and abdomen. Patients were divided into three groups depending on tumor location [upper esophagus (UE), middle esophagus, or lower esophagus (LE)] and analyzed clinicopathologically.

RESULTS

The LE group showed significantly more progressive ESCC in terms of tumor invasion (p = 0.025), node metastasis (p = 0.0071), and TNM stage (p = 0.0043). The LE group revealed a tendency to metastasize to extrathoracic (especially abdominal) nodes (p = 0.0008). Recurrent laryngeal node metastasis was increased in the UE group (p = 0.016). However, no prognostic differences were detected between groups according to tumor location. Likewise, subgroup analyses by surgical approach (open thoracotomy vs. thoracoscopy) and cancer stage (stage I/II, III, and IV) did not reveal any significant prognostic impact of tumor location.

CONCLUSION

Lymphatic spread varied by tumor location, but no prognostic impact of tumor location could be detected in patients with ESCC in spite of surgical approach or cancer stage.

Extracellular ATP-prinoceptor signaling and AMP-activated protein kinase regulate astrocytic glucose transporter 3 in an in vitro ischemia

Astrocytes become hypertrophic reactive in response to the ischemic stress, and they contribute to either protect or exacerbate neuronal damage, depending on the depth or duration of the stress. Astrocytes have more resistance to the ischemic stress than neurons, which is apparently due to active anerobic metabolic pathway in the emergency situation. We have been focused on the functional role of astrocytic glucose transporters in the ischemic condition. Under the physiological conditions, cultured astrocytes primarily express glucose transporter1 (GLUT1), and GLUT3 is only detected at extremely low levels. But astrocytes enhance GLUT3 expression through the signaling of nuclear factor-κ-light-chain-enhancer of activated B cells (NF-κB) under mild ischemic condition. It is reasonable since GLUT3 transports extracellular glucose about seven times faster than GLUT1, so astrocytes enhance the storage of intracellular glucose during the ischemia. However, other signaling cascades that regulate GLUT3 production remain unknown. Here we demonstrate that extracellular adenosine 5'-triphosphate (ATP)-P2Y receptor signaling also regulates GLUT3 expression. Under mild ischemic condition, astrocytes positively released existing intracellular or newly synthesized ATP by AMP-activated protein kinase (AMPK) signaling. The released extracellular ATP from pore channels activated ATP-sensitive P2Y receptor signaling, resulting in an increase in c-Fos and c-Jun proteins. Newly synthesized GLUT3 was regulated by those signaling since the inhibition of P2Y receptors or c-Fos/c-Jun signaling significantly reduced GLUT3 expression. Furthermore, the inhibition of P2Y receptors during the ischemic condition sustained intracellular ATP concentration, leading to a decrease in AMPK proteins. These results suggest AMPK-regulated ATP production triggers the release of ATP to activate P2Y receptor signaling, which is another candidate that regulates GLUT3 expression under the ischemic condition.

Negative-U system of carbon vacancy in 4H-SiC

Using electron paramagnetic resonance (EPR), energy levels of the carbon vacancy (V(C)) in 4H-SiC and its negative-U properties have been determined. Combining EPR and deep-level transient spectroscopy we show that the two most common defects in as-grown 4H-SiC--the Z(1/2) lifetime-limiting defect and the EH(7) deep defect--are related to the double acceptor (2-|0) and single donor (0|+) levels of V(C), respectively.

Expression of variant CD44, exon 6 in patients with metastatic pulmonary tumor

High expression ratios of CD44 variant 6 (CD44 V6) in patients with metastatic pulmonary tumor were found in those with primary lesions of cancer of the colon, uterus, larynx, liver and osteosarcoma. It was clarified that patients showing expression of CD44 variant 6 likely revealed pulmonary metastasis at earlier time following operations of primary cancer (p<0.05). CD44 V6, an adhesion molecule, was a factor to participate in pulmonary metastases from various organ cancers. No significant correlation was observed in survival between patients with CD44 V6 positive versus negative tumors, except laryngeal tumor after resection of primary or metastatic lung tumor. CD44 V6 related to its invasive and further metastatic functions in metastatic lung tumor. We suggest that cancer cells expressing the CD44 molecule especially V6 may adhere to vascular endothelium and hyaluronic acid in the lung. And cancer cells without this molecule liberated from the primary focuses hardly adhere to the pulmonary tissues supposedly resulting in delayed metastases and proliferations in the pulmonary tissues.

Effects of cigarette smoking on endurance performance levels of 16- to 19-year-old males

The purpose of this study was to explore the effects of cigarette smoking on the levels of endurance performance in teenagers. Longitudinal data of physical characteristics, smoking habits, exercise habits, and time records in both 1500-meter run and 10-kilometer run of 202 sixteen-to-nineteen-year-old male students were retrieved and analyzed retrospectively. The results showed that the performance levels of exercise-neversmokers in the 1500-meter run did improve as the subjects grew older, and that over the same period, the exercise-smokers did not improve but were able only to maintain their performance levels. The results of two way analysis of variance(ANOVA) indicated that smoking negatively and independently impacts how eighteen and nineteen-year-olds will perform in a 10-kilometer run. The reduced levels of endurance performance in the non-exercise smokers showed up in their results in the 10-kilometer run, and the diminished performance levels of the exercise-smokers were revealed in their 1500-meter run times. These results suggest that smokers obtain less benefits from training than non-smokers, and that we need to assess endurance performance levels among the young by paying careful attention to their smoking habits.

Fabrication of three-dimensional nano, micro and micro/nano scaffolds of porous poly(lactic acid) by electrospinning and comparison of cell infiltration by Z-stacking/three-dimensional projection technique

The use of electrospun extracellular matrix (ECM)-mimicking nanofibrous scaffolds for tissue engineering is limited by poor cellular infiltration. The authors hypothesised that cell penetration could be enhanced in scaffolds by using a hierarchical structure where nano fibres are combined with micron-scale fibres while preserving the overall scaffold architecture. To assess this, we fabricated electrospun porous poly(lactic acid) (PLA) scaffolds having nanoscale, microscale and combined micro/nano architecture and evaluated the structural characteristics and biological response in detail. Although the bioactivity was intermediate to that for nanofibre and microfibre scaffold, a unique result of this study was that the micro/nano combined fibrous scaffold showed improved cell infiltration and distribution than the nanofibrous scaffold. Although the cells were found to be lining the scaffold periphery in the case of nanofibrous scaffold, micro/nano scaffolds had cells dispersed throughout the scaffold. Further, as expected, the addition of nanoparticles of hydroxyapatite (nHAp) improved the bioactivity, although it did not play a significant role in cell penetration. Thus, this strategy of creating a three-dimensional (3D) micro/nano architecture that would increase the porosity of the fibrous scaffold and thereby improving the cell penetration, can be utilised for the generation of functional tissue engineered constructs in vitro.

Intracerebral microinjection of interleukin-4/interleukin-13 reduces β-amyloid accumulation in the ipsilateral side and improves cognitive deficits in young amyloid precursor protein 23 mice

We previously reported that the anti-inflammatory cytokine interleukin (IL)-4 induced selective clearance of oligomeric β-amyloid (Aβ(1-42)) in rat primary type 2 microglial cells. For the present study, we investigated whether IL-4 and IL-13 could activate microglial cells to induce Aβ clearance in vivo and improve cognitive deficits in APP23 mice, which are amyloid precursor protein transgenic mice. We administered an intracerebral microinjection of a mixture of IL-4 and IL-13 or of saline vehicle into one hemisphere of APP23 mice and their wild-type littermates, 4.5 and 9 months old, after which we evaluated the effects of these treatments on spatial learning and memory by Morris Water Maze test and on accumulated amounts of Aβ. The cytokine injection significantly improved memory deficits of 4.5-month-old APP23 mice, but did not do so in 9-month-old APP23 mice, even though similar Aβ reductions were observed in both age groups of APP23 mice in the ipsilateral neocortex. The cytokine injection improved memory impairment of 9-month-old wild-type (WT) mice in the probe trial. Immunohistochemical analysis of the 4.5-month-old APP23 mice revealed the presence of increased numbers of microglial cells at 2 days after the cytokine injection. In addition to induced CD36 expression in the activated microglia, increased expression of neprilysin, mainly in neurons, suggested that the cytokines improved the cognitive deficits via degradation and clearance of intra- and extraneuronal Aβ peptides, of buffer-extractable nonplaque form. Double immunostaining also revealed that most of the activated microglia had the M2-like phenotype. This unique mechanism of IL-4/IL-13-induced clearance of Aβ may provide an additional strategy to prevent and/or cure Alzheimer's disease at early stage.

Negative-feedback regulation of ATP release: ATP release from cardiomyocytes is strictly regulated during ischemia

Extracellular ATP acts as a potent agonist on cardiomyocytes, inducing a broad range of physiological responses via P2 purinoceptors. Its concentration in the interstitial space within the heart is elevated during ischemia or hypoxia due to its release from a number of cell types, including cardiomyocytes. However, the exact mechanism responsible for the release of ATP from cardiomyocytes during ischemia is not known. In this study, we investigated whether and how the release of ATP was strictly regulated during ischemia in cultured neonatal rat cardiomyocytes. Ischemia was mimicked by oxygen-glucose deprivation (OGD). Exposure of cardiomyocytes to OGD resulted in an increase in the concentration of extracellular ATP shortly after the onset of OGD (15 min), and the increase was reversed by treatment with blockers of maxi-anion channels. Unexpectedly, at 1 and 2h after the onset of OGD, the blocking of maxi-anion channels increased the concentration of extracellular ATP, and the increase was significantly suppressed by co-treatment with blockers of hemichannels, suggesting that ATP release via maxi-anion channels was involved in the suppression of ATP release via hemichannels during persistent OGD. Here we show the possibility that the release of ATP from cardiomyocytes was strictly regulated during ischemia by negative-feedback mechanisms; that is, maxi-anion channel-derived ATP-induced suppression of ATP release via hemichannels in cardiomyocytes.

Effect of isoproterenol on local contractile behaviors of rat cardiomyocytes measured by atomic force microscopy

Inotropic agents induce changes in the contraction amplitude and frequency of cardiomyocytes (CMs). However, it is unknown how local contractions of CMs treated by inotropic agents behave spatiotemporally. In this study, the effect of isoproterenol, a positive inotropic agent, on local contractions of isolated neonatal rat CMs was explored by atomic force microscopy (AFM). We observed that changes in local contraction amplitude of CM in the presence of isoproterenol were heterogeneous; they were unchanged or increased, at different positions, with respect to the amplitude of untreated CMs. Interestingly, spatial heterogeneities of local contraction amplitude of CM in the presence of isoproterenol did not obviously correlate with the local elasticity, indicating that the local contractions were facilitated by cooperative dynamics of the cytoskeletal structure in relatively large regions, rather than those just under AFM indentation. Moreover, local contraction amplitude of CM in the presence of isoproterenol was not proportional to that in the control condition, showing that the former change was no longer additive in local scales.

Meticillin-resistant Staphylococcus aureus and meticillin-susceptible S. aureus pneumonia: comparison of clinical and thin-section CT findings

OBJECTIVES

The purpose of this study was to compare the clinical and thin-section CT findings in patients with meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-susceptible S. aureus (MSSA).

METHODS

We retrospectively identified 201 patients with acute MRSA pneumonia and 164 patients with acute MSSA pneumonia who had undergone chest thin-section CT examinations between January 2004 and March 2009. Patients with concurrent infectious disease were excluded from our study. Consequently, our study group comprised 68 patients with MRSA pneumonia (37 male, 31 female) and 83 patients with MSSA pneumonia (32 male, 51 female). Clinical findings in the patients were assessed. Parenchymal abnormalities, lymph node enlargement and pleural effusion were assessed.

RESULTS

Underlying diseases such as cardiovascular were significantly more frequent in the patients with MRSA pneumonia than in those with MSSA pneumonia. CT findings of centrilobular nodules, centrilobular nodules with a tree-in-bud pattern, and bronchial wall thickening were significantly more frequent in the patients with MSSA pneumonia than those with MRSA pneumonia (p = 0.038, p = 0.007 and p = 0.039, respectively). In the group with MRSA, parenchymal abnormalities were observed to be mainly peripherally distributed and the frequency was significantly higher than in the MSSA group (p = 0.028). Pleural effusion was significantly more frequent in the patients with MRSA pneumonia than those with MSSA pneumonia (p = 0.002).

CONCLUSIONS

Findings from the evaluation of thin-section CT manifestations of pneumonia may be useful to distinguish between patients with acute MRSA pneumonia and those with MSSA pneumonia.

Inducible astrocytic glucose transporter-3 contributes to the enhanced storage of intracellular glycogen during reperfusion after ischemia

Glucose is a necessary source of energy to sustain cell activities and homeostasis in the brain, and enhanced glucose transporter (GLUT) activities are protective of cells during energy depletion including brain ischemia. Here we investigated whether and if so how the astrocytic expression of GLUTs crucial for the uptake of glucose changes in ischemic conditions. Under physiological conditions, cultured astrocytes primarily expressed GLUT1, and GLUT3 was only detected at extremely low levels. However, exposure to ischemic stress increased the expression of not only GLUT1 but also GLUT3. During ischemia, cultured astrocytes significantly increased production of the transcription factor nuclear factor-κB (NF-κB), leading to an increase in GLUT3 expression. Moreover, astrocytic GLUT3 was responsible for the enhanced storage of intracellular glucose during reperfusion, resulting in increased resistance to lethal ischemic stress. These results suggested that astrocytes promptly increase GLUT3 production in situations such as ischemia, and much glucose is quickly taken up, possibly contributing to the protection of astrocytes from ischemic damage.

Oxidative stress-induced formation of a positive-feedback loop for the sustained activation of p38 MAPK leading to the loss of cell division in cardiomyocytes soon after birth

Shortly after birth, mammalian cardiomyocytes irreversibly exit from the cell cycle and become terminally differentiated. The cellular mechanisms responsible for the cessation of cell division and terminal differentiation of cardiomyocytes soon after birth have intrigued developmental biologists as well as cardiovascular physicians, but the genetic cues for the irreversible exit from the cell cycle soon after birth remain largely unknown. We examined whether and if so how oxidative stress to mammalian hearts during fetal-neonatal transition produces changes in the proliferative activity and terminal differentiation of cardiomyocytes. Scavenging of reactive oxygen species (ROS) during fetal-neonatal transition, especially after birth, resulted in an increase in the proliferative activity and a decrease in the ratio of binucleated cardiomyocytes. Exposure to ROS in cultured cardiomyocytes increased the activity of p38 MAPK and the expression of connexin 43 (Cx43). Not only knockdown of Cx43 using siRNA but also the inhibition of p38 MAPK activity resulted in a significant decrease in the production of ROS in cardiomyocytes, suggesting that the signaling pathway ROS-p38 MAPK-Cx43 (especially, Cx43 at mitochondria, mtCx43) constituted a closed regulatory system with positive feedback. In addition, continuous scavenging of ROS or suppression of p38 MAPK activity for 4 days after birth resulted in a significant decrease in the expression of mtCx43 and in the number of binucleated cardiomyocytes. This study demonstrated that the ROS-induced formation of a positive-feedback loop ROS-p38 MAPK-mtCx43 for the sustained activation of p38 MAPK soon after birth possibly contributes to the loss of cell division and binucleation in mammalian cardiomyocytes.

Gender differences in hand stability of normal young people assessed at low force levels

To examine gender differences in hand stability, finger position and force holding tasks at low force levels were conducted with 30 male and 30 female young adults. Total fluctuation was defined as the standard deviation of measured data and fluctuation and the 10-Hz component of the physiological tremor were compared between maleand female subjects. In all tasks, the total fluctuation and the 10-Hz tremor were significantly larger in male subjects than females. On average, the fluctuation was 1.3 times larger and the 10-Hz tremor was 1.6 times larger. The results of this study suggest that women have superior hand stability compared with men at low force levels. Finger length, maximal voluntary contraction and surface electromyography were also measured and factors related to gender differences in hand stability are discussed. STATEMENT OF RELEVANCE: Hand stability is crucial for precise manual operations. This study demonstrated gender differences in hand steadiness at low force levels. Though hand dexterity cannot be explained only by hand stability, the results of this study are useful not only for occupational aptitude tests but also for neuropsychological tests.

Impact of Grain Boundary Character on Electrical Property in Polycrystalline Silicon

Grain boundaries in polycrystalline silicon are most likely to generate localized states in band gap. The localized states play a dominant role in determining the performance of solar cells by acting as traps or recombination center of carriers. In the present investigation, the scanning electron microscope - electron channeling pattern(SEM/ECP) method and SEM - electron back scattered diffraction pattern(SEM/EBSD) technique were applied to characterize the grain boundaries in p-type polycrystalline silicon with 99.999%(5N) in purity. Thereafter, temperature dependence of electrical activity of individual grain boundaries was measured by an electron beam induced current(EBIC) technique.

It has been found that temperature dependence of EBIC contrast at grain boundaries can change, depending on the misorientation angle the orientation of the boundary plane. The results can be explained by the difference in the position of the localized state within the band gap on the basis of the Shockley-Read-Hall statistics. The {111} ∑3 symmetrical tilt boundary has shallow states, while high ∑ boundaries have deep states. Low angle boundaries reveal high electrical activities. The EBIC contrast at low angle boundaries was found to increase with increasing misorientation angle up to 2° followed by an almost constant value. High electrical activity at low angle boundaries is probably attributed to a stress field of primary dislocations forming low angle boundaries.