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result(s) for
"Minami, K"
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Development of micro mechanical device having two-dimensional array of micro chambers for cell stretching
2018
This paper presents a novel cell stretching micro device having two-dimensional array of micro chambers. It enables an in situ time-lapse observation of stretched cell by using an optical microscope with high measurement efficiency. The presented device consists of a cell culture dish and the array of micro chambers made of silicone elastomer and extension structures made of photocurable resin, and is fabricated with MEMS technology. The fabrication process of the thin micro chamber array combines photoresist mold and lift-off process based on conventional photolithography. The fabricated device has 134 micro chambers in 5μm or less thickness. It was demonstrated that the fabricated micro device could be used to make in-situ time-lapse observation of cell responses to stretching under optical microscopy. In addition, the influence of the chamber thickness to the quality of the microscope image observed was evaluated. It is confirmed that the proposed device having two-dimensional array of the thin micro chambers makes it possible to observe cell response for stretch stimuli with high quality and efficiency.
Journal Article
Assessment of spatio-temporal variations of macroalgal canopies and fish schools before and after coastal desertification using acoustic methods
Macroalgal canopies, which provide nutrients and habitats for many invertebrates and fishes in coastal waters, are disappearing worldwide. The simultaneous assessment of changes in macroalgae and fish distribution before and after coastal desertification, including deeper coastal waters where beyond macroalgae growth need attention. Therefore, we investigated their spatial distribution in the coastal waters off southwestern Japan in late autumn and winter using the acoustic method combined with visual observation. The number of fish schools was higher in late autumn than in winter, while they had similar acoustic backscattering strength (Sv) and school size, tended to be distributed in shallower waters. The number was lower after the macroalgae disappeared in both seasons, while the average Sv was higher, and the size was larger. They were distributed in similar water depths during the winter season. Fewer fish schools and higher Sv were observed in deeper waters after the macroalgae disappeared. We concluded that more fishes moved to shallower waters in the autumn than in the winter because of higher water temperatures. Macroalgae benefited small juvenile fishes in both shallow and deep coastal waters. Further studies on the distribution of specific species are expected for the assessment and restoration of the macroalgal ecosystem.
Journal Article
Potentiation of ghrelin signaling attenuates cancer anorexia–cachexia and prolongs survival
2011
Cancer anorexia–cachexia syndrome is characterized by decreased food intake, weight loss, muscle tissue wasting and psychological distress, and this syndrome is a major source of increased morbidity and mortality in cancer patients. This study aimed to clarify the gut–brain peptides involved in the pathogenesis of the syndrome and determine effective treatment for cancer anorexia–cachexia. We show that both ghrelin insufficiency and resistance were observed in tumor-bearing rats. Corticotropin-releasing factor (CRF) decreased the plasma level of acyl ghrelin, and its receptor antagonist, α-helical CRF, increased food intake of these rats. The serotonin 2c receptor (5-HT2cR) antagonist SB242084 decreased hypothalamic CRF level and improved anorexia, gastrointestinal (GI) dysmotility and body weight loss. The ghrelin receptor antagonist (D-Lys3)-GHRP-6 worsened anorexia and hastened death in tumor-bearing rats. Ghrelin attenuated anorexia–cachexia in the short term, but failed to prolong survival, as did SB242084 administration. In addition, the herbal medicine rikkunshito improved anorexia, GI dysmotility, muscle wasting, and anxiety-related behavior and prolonged survival in animals and patients with cancer. The appetite-stimulating effect of rikkunshito was blocked by (D-Lys3)-GHRP-6. Active components of rikkunshito, hesperidin and atractylodin, potentiated ghrelin secretion and receptor signaling, respectively, and atractylodin prolonged survival in tumor-bearing rats. Our study demonstrates that the integrated mechanism underlying cancer anorexia–cachexia involves lowered ghrelin signaling due to excessive hypothalamic interactions of 5-HT with CRF through the 5-HT2cR. Potentiation of ghrelin receptor signaling may be an attractive treatment for anorexia, muscle wasting and prolong survival in patients with cancer anorexia–cachexia.
Journal Article
Correction to: Development of micro mechanical device having two-dimensional array of micro chambers for cell stretching
2018
The original article has been corrected. Instances of the character \"μ\" should be replaced by the term \"micro\".
Journal Article
A distinct function of the retinoblastoma protein in the control of lipid composition identified by lipidomic profiling
2017
Here, by combining lipidomics with transcriptome analysis, we demonstrate that Rb depletion in mouse embryonic fibroblastss induces significant alterations in their lipid composition. We discovered that Rb depletion induced increase in lysophosphatidylserine, diacylglycerol (DAG), fatty acid (FA), acylcarnitine, phosphatidylcholine (PC), arachidonoyl ethanolamine, and decrease in phosphatidylglycerol, monoacylglycerol, without change in total lipid per protein levels. Analysis of the acyl chain composition of DAG, PC and phosphatidylserine revealed increase of saturated and mono-unsaturated acyl chains with specific carbon chain length. Consistently, we observed that Rb depletion increased the levels of fatty acids with the corresponding carbon chain length and number of carbon–carbon double bondssuch as myristic acid (14:0), palmitic acid (16:0), stearic acid (18:0) and all forms of FA 18:1. Microarray analysis revealed that Rb depletion induced significant upregulation of enzymes involved in elongation and desaturation of fatty acids. Among these, we found that elongation of long chain fatty acid family member 6 (Elovl6) and stearoyl-CoA desaturase 1 (Scd1) are the most robustly controlled by Rb possibly through E2F and sterol regulatory element-binding protein transcription factors. Depletion of Elovl6 or Scd1 significantly suppressed colony formation, sphere formation and xenograft tumor growth of Rb-deficient tumor cells. Suppression of self-renewal by the SCD1 inhibitor was rescued upon supplementation of the mono-unsaturated fatty acids generated by this enzyme. This study suggests a novel role for Rb in suppressing the malignant progression of tumors by controlling the lipid composition.
Journal Article
Plasma eNOS Concentration in Healthy Pregnancy and in Hypertensive Disorders of Pregnancy: Evidence of Reduced Concentrations in Pre-Eclampsia from Two Independent Studies
by
Romão-Veiga, Mariana
,
Kaihara, Julyane N. S.
,
Palei, Ana C. T.
in
Acids
,
Bioavailability
,
Blood pressure
2023
Hypertensive disorders of pregnancy (HDP), comprising gestational hypertension (GH) and pre-eclampsia (PE), are leading causes of maternal and perinatal morbidity and mortality. Both GH and PE are characterized by new-onset hypertension, but PE additionally includes proteinuria and/or end-organ damage. Impaired nitric oxide (NO) bioavailability may lead to endothelial dysfunction in GH and PE, and the primary source of vascular NO is endothelial NO synthase (eNOS). However, no previous study has investigated plasma eNOS concentrations in patients with GH and PE. In this study, we compared plasma eNOS concentrations in healthy pregnancies and HDP in two independent cohorts. The primary study included 417 subjects, with 43 non-pregnant (NP) and 156 healthy pregnant (HP) women and 122 patients with GH and 96 with PE. The replication study included 85 pregnant women (41 healthy and 44 pre-eclamptic). Plasma concentrations of eNOS were measured using a commercial ELISA kit provided by R&D Systems, and plasma nitrite concentrations were assessed using two ozone-based chemiluminescence assays. Correlations between plasma eNOS concentrations and plasma nitrite concentrations, as well as clinical and biochemical parameters, were evaluated by either Spearman’s or Pearson’s tests. In the primary study, NP women and HDP had significantly lower plasma eNOS concentrations compared to HP; concentrations were even lower in PE compared to GH. Plasma eNOS concentrations were reduced but not significant in early-onset PE, PE with severe features, preterm birth, and intrauterine growth restriction. No correlation was observed between plasma eNOS and nitrite levels. In HDP, there was a significant positive correlation between levels of eNOS and hemoglobin (r = 0.1496, p = 0.0336) as well as newborn weight (r = 0.1487, p = 0.0316). Conversely, a negative correlation between eNOS levels and proteinuria was observed (r = −0.2167, p = 0.0179). The replication study confirmed significantly reduced plasma concentrations of eNOS in PE compared to HP. Our findings provide evidence of reduced plasma eNOS concentrations in HDP; they were particularly lower in PE compared to GH and HP in two independent studies.
Journal Article
Evaluation of Electrostatic Force on Bipolar Charged Electret
2014
This paper presents an evaluation of an electrostatic vibration energy harvester with the bipolar charged electret. The energy harvester with the size of 13 × 12 × 1.2 mm3 was fabricated. The output power of the bipolar charged with ±250 V harvester was 9 μW when the acceleration was 1.4 g at 352 Hz with 0.9 MΩ load resistance. The effectiveness against the velocity-damped resonant-generator (VDRG) limit was 2.5%. The electrostatic forces of the actual device with DC bias, which simulates charged electret with monopolar and bipolar were experimentally and numerically verified. We estimated the electrostatic force by measuring the vibration amplitude versus applied acceleration of the electret mass. As a result, we investigated the bipolar charged device can reduce the effect of electrostatic force as low as no bias condition. The numerical model of the energy harvester considering the electrostatic force by FEM static analysis was also established. The comparison between the numerical model and the measurement results showed a similar inclination.
Journal Article
Comparison of postoperative surface light scattering of different intraocular lenses
2009
Aims:This retrospective study was conducted to compare postoperative surface scattering of four kinds of intraocular lens (IOL).Methods:Sixty-seven eyes of 67 patients who had undergone cataract surgery were enrolled in this study. One of four IOLs was used in the patients; MA60BM in 17 patients (MA group), SA60AT in 17 patients (SA group), AR40 in 16 patents (AR group) and ClariFlex in 17 patients (CL group). Measurement of scattering from the anterior surface of the IOL was measured with area densitometry using a Scheimpflug camera (EAS-1000, Nidek, Aichi) for 3 years after the surgery.Results:The density of IOL surface scattering increased starting 1 year after surgery and throughout the 3-year period in the MA group and starting at 6 months through 3 years in the SA group, whereas the density was stable in the AR and CL groups. The density of surface scattering in the MA and SA groups at 3 years after surgery was significantly higher than in the AR and CL groups.Conclusion:The surface scattering of MA60BM and SA60AT is higher than that of AR40 and ClariFlex. The grades of surface scattering differ among the manufacturers, even with the same acrylic material.
Journal Article
Electrostatic Energy Harvester Utilizing High Density of Electrode for Higher Output Power
2015
In this study, we report an improvement of output power from an electret type vibration energy harvester. Typical crossing-area change harvester has a stripe-shaped electret and counter electrode for making the capacitance change. In order to improve space efficiency, the counter electrodes are divided and arraignment with the same pitch of the electret. We investigate that adjoining the counter electrodes, the fringing effect is decreased and the capacitance change between the electrodes is larger than the conventional design from FEM analysis. The output power of 2.5 μW and 5.3 μW are obtained in each kind of counter electrode with the applied acceleration of 3 G at 350 Hz, which is about 2 or 4 times as high as our previous work.
Journal Article
Gs/Gq signaling switch in β cells defines incretin effectiveness in diabetes
by
Tolö, Johan
,
Rorsman, Patrik
,
Miki, Takashi
in
Animals
,
ca2+ influx
,
Chromogranins - genetics
2020
By restoring glucose-regulated insulin secretion, glucagon-like peptide-1-based (GLP-1-based) therapies are becoming increasingly important in diabetes care. Normally, the incretins GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) jointly maintain normal blood glucose levels by stimulation of insulin secretion in pancreatic β cells. However, the reason why only GLP-1-based drugs are effective in improving insulin secretion after presentation of diabetes has not been resolved. ATP-sensitive K+ (KATP) channels play a crucial role in coupling the systemic metabolic status to β cell electrical activity for insulin secretion. Here, we have shown that persistent membrane depolarization of β cells due to genetic (β cell-specific Kcnj11-/- mice) or pharmacological (long-term exposure to sulfonylureas) inhibition of the KATP channel led to a switch from Gs to Gq in a major amplifying pathway of insulin secretion. The switch determined the relative insulinotropic effectiveness of GLP-1 and GIP, as GLP-1 can activate both Gq and Gs, while GIP only activates Gs. The findings were corroborated in other models of persistent depolarization: a spontaneous diabetic KK-Ay mouse and nondiabetic human and mouse β cells of pancreatic islets chronically treated with high glucose. Thus, a Gs/Gq signaling switch in β cells exposed to chronic hyperglycemia underlies the differential insulinotropic potential of incretins in diabetes.
Journal Article