RESUMEN
The ex vivo generation of platelets from human-induced pluripotent cells (hiPSCs) is expected to compensate donor-dependent transfusion systems. However, manufacturing the clinically required number of platelets remains unachieved due to the low platelet release from hiPSC-derived megakaryocytes (hiPSC-MKs). Here, we report turbulence as a physical regulator in thrombopoiesis in vivo and its application to turbulence-controllable bioreactors. The identification of turbulent energy as a determinant parameter allowed scale-up to 8 L for the generation of 100 billion-order platelets from hiPSC-MKs, which satisfies clinical requirements. Turbulent flow promoted the release from megakaryocytes of IGFBP2, MIF, and Nardilysin to facilitate platelet shedding. hiPSC-platelets showed properties of bona fide human platelets, including circulation and hemostasis capacities upon transfusion in two animal models. This study provides a concept in which a coordinated physico-chemical mechanism promotes platelet biogenesis and an innovative strategy for ex vivo platelet manufacturing.
Asunto(s)
Plaquetas/metabolismo , Técnicas de Cultivo de Célula/métodos , Trombopoyesis/fisiología , Reactores Biológicos , Técnicas de Cultivo de Célula/instrumentación , Humanos , Hidrodinámica , Células Madre Pluripotentes Inducidas/metabolismo , Megacariocitos/metabolismo , Megacariocitos/fisiologíaRESUMEN
It is known that co-cultivation of green algae with heterotrophic microorganisms, such as yeast, improves green algae's growth potential and carbon dioxide fixation, even under low CO2 concentration conditions such as the atmosphere. Introducing mutations into green algae is also expected to enhance their growth potential. In this study, we sought to improve the growth potential of a co-culture system of the green algae Chlamydomonas reinhardtii and the yeast Saccharomyces cerevisiae by introducing mutations into the green algae. Additionally, we performed a transcriptome analysis of the co-culture of the green algae mutant strain with yeast, discussing the interaction between the green algae mutant strain and the yeast. When the green algae mutant strain was co-cultured with yeast, the number of green algae cells reached 152 × 105 cells/mL after 7 days of culture. This count was 2.6 times higher than when the wild-type green algae strain was cultured alone and 1.6 times higher than when the wild-type green algae strain and yeast were co-cultured. The transcriptome analysis also indicated that the primary reason for the increased growth potential of the green algae mutant strain was its enhanced photosynthetic activity and nitrogen utilization efficiency.
Asunto(s)
Chlorophyta , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Técnicas de Cocultivo , Fotosíntesis , Chlorophyta/genética , Mutagénesis , Dióxido de CarbonoRESUMEN
The early prediction of neurological outcomes is useful for out-of-hospital cardiac arrest (OHCA). The initial pH was associated with neurological outcomes, but the values varied among the studies. Patients admitted to our division with OHCA of cardiac origin between January 2015 and December 2022 were retrospectively examined (N = 199). A good neurological outcome was defined as a Glasgow-Pittsburgh cerebral performance category (CPC) of 1-2 at discharge. Patients were divided according to the achievement of recovery of spontaneous circulation (ROSC) on hospital arrival, and the efficacy of pH in predicting good neurological outcomes was compared. In patients with ROSC on hospital arrival (N = 100), the initial pH values for good and poor neurological outcomes were 7.26 ± 0.14 and 7.09 ± 0.18, respectively (p < 0.001). In patients without ROSC on hospital arrival (N = 99), the initial pH values for good and poor neurological outcomes were 7.06 ± 0.23 and 6.92 ± 0.15, respectively (p = 0.007). The pH associated with good neurological outcome was much lower in patients without ROSC than in those with ROSC on hospital arrival (P = 0.003). A higher initial pH is associated with good neurological outcomes in patients with OHCA. However, the pH for a good or poor neurological outcome depends on the ROSC status on hospital arrival.
Asunto(s)
Reanimación Cardiopulmonar , Paro Cardíaco Extrahospitalario , Humanos , Paro Cardíaco Extrahospitalario/diagnóstico , Paro Cardíaco Extrahospitalario/terapia , Estudios Retrospectivos , Hospitales , Concentración de Iones de HidrógenoRESUMEN
PURPOSE: CO2 fixation methods using green algae have attracted considerable attention because they can be applied for the fixation of dilute CO2 in the atmosphere. However, green algae generally exhibit low CO2 fixation efficiency under atmospheric conditions. Therefore, it is a challenge to improve the CO2 fixation efficiency of green algae under atmospheric conditions. Co-cultivation of certain microalgae with heterotrophic microorganisms can increase the growth potential of microalgae under atmospheric conditions. The objective of this study was to determine the culture conditions under which the growth potential of green algae Chlamydomonas reinhardtii is enhanced by co-culturing with the yeast Saccharomyces cerevisiae, and to identify the cause of the enhanced growth potential. RESULTS: When C. reinhardtii and S. cerevisiae were co-cultured with an initial green algae to yeast inoculum ratio of 1:3, the cell concentration of C. reinhardtii reached 133 × 105 cells/mL on day 18 of culture, which was 1.5 times higher than that of the monoculture. Transcriptome analysis revealed that the expression levels of 363 green algae and 815 yeast genes were altered through co-cultivation. These included genes responsible for ammonium transport and CO2 enrichment mechanism in green algae and the genes responsible for glycolysis and stress responses in yeast. CONCLUSION: We successfully increased C. reinhardtii growth potential by co-culturing it with S. cerevisiae. The main reasons for this are likely to be an increase in inorganic nitrogen available to green algae via yeast metabolism and an increase in energy available for green algae growth instead of CO2 enrichment.
Asunto(s)
Chlamydomonas reinhardtii , Técnicas de Cocultivo , Saccharomyces cerevisiae , Chlamydomonas reinhardtii/crecimiento & desarrollo , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crecimiento & desarrollo , Saccharomyces cerevisiae/metabolismo , Técnicas de Cocultivo/métodos , Dióxido de Carbono/metabolismo , Perfilación de la Expresión GénicaRESUMEN
Heart rate is a crucial vital sign and a valuable indicator for assessing the physical and psychological condition of a target animal. Heart rate contributes to (1) fundamental information for cognitive research, (2) an indicator of psychological and physical stress, and (3) improving the animal welfare of captive animals, especially in nonhuman primate studies. Heart rate has been measured using a contact-type device; however, the device burdens the target animals and that there are risks associated with anesthesia during installation. This study explores the application of heartbeat measurement techniques using millimeter-wave radar, primarily developed for humans, as a remote and noninvasive method for measuring the heart rate of nonhuman primates. Through a measurement test conducted on two chimpanzees, we observed a remarkable correspondence between the peak frequency spectrum of heart rate estimated using millimeter-wave radar and the mean value obtained from electrocardiograph data, thereby validating the accuracy of the method. To the best of our knowledge, this is the first demonstration of the precise measurement of great apes' heart rate using millimeter-wave radar technology. Compared to heart rate measurement using video analysis, the method using millimeter-wave radar has the advantage that it is less susceptible to weather and lighting conditions and that measurement techniques for multiple individuals have been developed for human subjects, while its disadvantage is that validation of measurement from long distances has not been completed. Another disadvantage common to both methods is that measurement becomes difficult when the movement of the target individual is large. The possibility of noncontact measurement of heart rate in wild and captive primates will undoubtedly open up a new research area while taking animal welfare into consideration.
Asunto(s)
Frecuencia Cardíaca , Pan troglodytes , Radar , Animales , Pan troglodytes/fisiología , Masculino , Femenino , Electrocardiografía/veterinaria , Electrocardiografía/instrumentaciónRESUMEN
In yeast metabolic engineering, there is a need for technologies that simultaneously suppress and regulate the expression of multiple genes and improve the production of target chemicals. In this study, we aimed to develop a novel technology that simultaneously suppresses the expression of multiple genes by combining RNA interference with global metabolic engineering strategy. Furthermore, using ß-carotene as the target chemical, we attempted to improve its production by using the technology. First, we developed a technology to suppress the expression of the target genes with various strengths using RNA interference. Using this technology, total carotenoid production was successfully improved by suppressing the expression of a single gene out of 10 candidate genes. Then, using this technology, RNA interference strain targeting 10 candidate genes for simultaneous suppression was constructed. The total carotenoid production of the constructed RNA interference strain was 1.7 times compared with the parental strain. In the constructed strain, the expression of eight out of the 10 candidate genes was suppressed. We developed a novel technology that can simultaneously suppress the expression of multiple genes at various intensities and succeeded in improving carotenoid production in yeast. Because this technology can suppress the expression of any gene, even essential genes, using only gene sequence information, it is considered a useful technology that can suppress the formation of by-products during the production of various target chemicals by yeast.
Asunto(s)
Carotenoides , Regulación Fúngica de la Expresión Génica , Ingeniería Metabólica , Saccharomyces cerevisiae , beta Caroteno , Ingeniería Metabólica/métodos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Carotenoides/metabolismo , beta Caroteno/metabolismo , beta Caroteno/biosíntesis , Interferencia de ARNRESUMEN
ß-Carotene is an attractive compound and that its biotechnological production can be achieved by using engineered Saccharomyces cerevisiae. In a previous study, we developed a technique for the efficient establishment of diverse mutants through the introduction of point and structural mutations into the yeast genome. In this study, we aimed to improve ß-carotene production by applying this mutagenesis technique to S. cerevisiae strain that had been genetically engineered for ß-carotene production. Point and structural mutations were introduced into ß-carotene-producing engineered yeast. The resulting mutants showed higher ß-carotene production capacity than the parental strain. The top-performing mutant, HP100_74, produced 37.6 mg/L of ß-carotene, a value 1.9 times higher than that of the parental strain (20.1 mg/L). Gene expression analysis confirmed an increased expression of multiple genes in the glycolysis, mevalonate, and ß-carotene synthesis pathways. In contrast, expression of ERG9, which functions in the ergosterol pathway competing with ß-carotene production, was decreased in the mutant strain. The introduction of point and structural mutations represents a simple yet effective method for achieving mutagenesis in yeasts. This technique is expected to be widely applied in the future to produce chemicals via metabolic engineering of S. cerevisiae.
Asunto(s)
Ingeniería Metabólica , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , beta Caroteno , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , beta Caroteno/biosíntesis , beta Caroteno/metabolismo , Ingeniería Metabólica/métodos , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Mutación , Regulación Fúngica de la Expresión Génica , Carotenoides/metabolismo , Mutagénesis , Mutación Puntual , Ácido Mevalónico/metabolismo , Vías Biosintéticas/genética , Farnesil Difosfato Farnesil TransferasaRESUMEN
Microbial 3-hydroxypropionic acid (3-HP) production can potentially replace petroleum-based production methods for acrylic acid. Here, we constructed a yeast strain that expressed enzymes related to 3-HP biosynthesis within the mitochondria. This approach aimed to enhance the 3-HP production by utilizing the mitochondrial acetyl-CoA, an important intermediate for synthesizing 3-HP. The strain that expressed 3-HP-producing enzymes in the mitochondria (YPH-mtA3HP) showed improved production of 3-HP compared to that shown by the strain expressing 3-HP-producing enzymes in the cytosol (YPH-cyA3HP). Additionally, cMCR was overexpressed, which regulates a rate-limiting reaction in synthesizing 3-HP. In this study, we aimed to further enhance 3-HP production by expressing multiple copies of cMCR in the mitochondria using the δ-integration strategy to optimize the expression level of cMCR (YPH-mtA3HPx*). The results of flask-scale cultivation showed that 3-HP production by cMCR δ-integration was significantly higher, exhibiting a yield of 160 mg/L in YPH-mtA3HP6* strain and 257 mg/L in YPH-mtA3HP22* strain. Notably, YPH-mtA3HP22*, exhibited the highest 3-HP titer, which was 3.2-fold higher than that of YPH-cyA3HP. Our results demonstrated the potential of utilizing the mitochondrial compartment within S. cerevisiae for enhancing 3-HP production.
Asunto(s)
Oxidorreductasas , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Acetilcoenzima A/metabolismo , Oxidorreductasas/metabolismo , Ácido Láctico/metabolismo , Ingeniería Metabólica/métodosRESUMEN
BACKGROUND: The accumulation of advanced glycation end products (AGEs) is associated with cardiovascular events in patients with cardiovascular disease (CVD). However, the relationship between the AGEs measured by an AGEs sensor noninvasively at the fingertip and prognosis in patients with CVD remains unclear. Therefore, this study aimed to determine the relationship between AGEs score and prognosis among patients with CVD. METHODS: A total of 191 outpatients with CVD were included. AGEs score were measured using an AGEs sensor and the patients were classified into groups by the median value of AGEs score. The incidence of major adverse cardiovascular and cerebrovascular events (MACCE) at 30 months was compared between high- and low-AGEs score groups. In addition, receiver operating characteristic (ROC) curve analysis was used to calculate cutoff value for the AGEs score, which discriminates the occurrence of MACCE. Cox regression analysis was performed to identify the factors associated with the presence of MACCE. MACCE included cardiac death, myocardial infarction, percutaneous coronary intervention, heart failure, and stroke. RESULTS: AGEs score was normally distributed, with a median value of 0.51. No significant intergroup differences were found in laboratory findings, physical functions, or medications. The high-AGEs score group had a significantly higher incidence of MACCE than the low-AGEs score group (27.1 vs. 10.5%, P = 0.007). A high-AGEs score was a risk factor for MACCE (hazard ratio, 2.638; 95% confidence interval, 1.271-5.471; P = 0.009). After the adjustment for confounders other than 6-min walking distance, the AGEs score remained a factor associated with the occurrence of MACCE. The best cutoff AGEs score for the detection of MACCE was 0.51 (area under the curve, 0.642; P = 0.008; sensitivity, 72.2%; specificity, 54.8%). CONCLUSIONS: AGEs score measured at the fingertip in patients with CVD is associated with MACCE. AGEs score, which can be measured noninvasively and easily, may be useful as an assessment for the secondary prevention of CVD in patients with CVD.
Asunto(s)
Enfermedades Cardiovasculares , Insuficiencia Cardíaca , Infarto del Miocardio , Humanos , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/epidemiología , Pacientes Ambulatorios , Productos Finales de Glicación AvanzadaRESUMEN
The capability of Escherichia coli BW25113 to adsorb palladium (Pd) ions in a single-gene-knockout library was investigated using high-throughput screening. The results revealed that compared to BW25113, nine strains promoted Pd ion adsorption, whereas 22 strains repressed. Although further studies are required because of the first screening results, our results will provide a new perspective for improving the biosorption.
Asunto(s)
Escherichia coli , Paladio , Adsorción , Iones , Concentración de Iones de HidrógenoRESUMEN
BACKGROUND: In cases of intermittent claudication (IC) where traditionally noninvasive management yields unsatisfactory results, revascularization strategy in IC patients is generally decided based on anatomical considerations and the availability of a saphenous vein graft. Life expectancy should also be considered. This study aimed to investigate the relationship between the 11-item modified frailty index (mFI-11) and the overall survival (OS) in patients with IC who underwent vascular bypass surgery to facilitate revascularization strategy selection. METHODS: We reviewed the records of 144 consecutive patients (153 lower limbs) who underwent infrainguinal bypass for IC between 2011 and 2020. Patients were divided into 2 groups based on their mFI-11 score: high frailty (H), mFI score >0.3; and low frailty (L), mFI score ≤0.3. The OS was compared among the 2 groups. Rates of graft patency and freedom from major adverse limb event (ffMALE) were also determined and compared. RESULTS: Five-year OS in the L and H groups was 92% and 55% (P < 0.001). Multivariate analysis showed that mFI, age, and end-stage renal disease were independent predictors of OS. Five-year rates of primary and secondary patency and ffMALE for vein grafts were 81%, 91%, and 94%, respectively; those for prosthetic grafts were 65%, 80%, and 84%, respectively; the differences were not significant. CONCLUSIONS: The mFI-11 was a helpful tool in predicting OS for patients with IC who underwent vascular bypass surgery. Those with H should not undergo open revascularization; however, for IC patients who have either not responded to a regimen of exercise and medication, or have specifically requested a more aggressive approach, obtaining a good score in frailty assessment is useful in determining whether or not bypass surgery would be a viable option.
Asunto(s)
Fragilidad , Claudicación Intermitente , Humanos , Claudicación Intermitente/diagnóstico por imagen , Claudicación Intermitente/cirugía , Fragilidad/complicaciones , Fragilidad/diagnóstico , Resultado del Tratamiento , Grado de Desobstrucción Vascular , Factores de Riesgo , Pronóstico , Estudios RetrospectivosRESUMEN
The modification of gene expression is being researched in the production of useful chemicals by metabolic engineering of the yeast Saccharomyces cerevisiae. When the expression levels of many metabolic enzyme genes are modified simultaneously, the expression ratio of these genes becomes diverse; the relationship between the gene expression ratio and chemical productivity remains unclear. In other words, it is challenging to predict phenotypes from genotypes. However, the productivity of useful chemicals can be improved if this relationship is clarified. In this study, we aimed to construct a machine-learning model that can be used to clarify the relationship between gene expression levels and D-lactic acid productivity and predict the optimal gene expression level for efficient D-lactic acid production in yeast. A machine-learning model was constructed using data on D-lactate dehydrogenase and glycolytic genes expression (13 dimensions) and D-lactic acid productivity. The coefficient of determination of the completed machine-learning model was 0.6932 when using the training data and 0.6628 when using the test data. Using the constructed machine-learning model, we predicted the optimal gene expression level for high D-lactic acid production. We successfully constructed a machine-learning model to predict both D-lactic acid productivity and the suitable gene expression ratio for the production of D-lactic acid. The technique established in this study could be key for predicting phenotypes from genotypes, a problem faced by recent metabolic engineering strategies.
Asunto(s)
Ácido Láctico , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Ácido Láctico/metabolismo , Glucólisis , Ingeniería Metabólica/métodos , L-Lactato Deshidrogenasa/genética , Expresión GénicaRESUMEN
We propose a de novo glycan display approach that combines metabolic labeling and a glycan-caging strategy as a facile editing method for cell-surface glycans. This method enables the introduction of antigen glycans onto cancer cells to induce immune responses through antibody recruiting. The caging strategy prevents the capture of α-rhamnose (an antigen glycan) by endogenous antibodies during the introduction of the glycan to the targeted cell surface, and subsequent uncaging successfully induces immune responses. Therefore, this study proposes a practical method for editing the cell-surface glycocalyx under promiscuous conditions, such as those in vivo, which paves the way for the development of glycan function analysis and regulation.
Asunto(s)
Anticuerpos , Polisacáridos , Polisacáridos/metabolismo , Membrana Celular/metabolismo , RamnosaRESUMEN
A hydrophobic surface or coating is required for surface protection, anti-fouling, adhesion, and other applications. For the achievements of hydrophobic properties, fluorine-based coatings, such as the introduction of trifluoromethyl or difluoromethylene groups, are conventionally employed. Recent developments in synthetic chemistry have indicated other organic fluoroalkyl groups that are suitable for achieving a more hydrophobic surface. In this study, we focused on the hydrophobic properties of the pentafluorosulfanyl (-SF5) group. We synthesized polymethacrylates with -SF5 groups or other functional groups (-CF3, -CH3, and -H) in their side chains and evaluated their hydrophobicity based on contact angles of water and ethylene glycol and the affinities of their films to water through neutron reflectivity measurements to demonstrate the superior hydrophobic properties of the -SF5 group. The water contact angle on the polymethacrylate film with -SF5 groups was larger, which suggested that the surface free energy was lower than that of the other polymethacrylate thin films with pendant side chains of -CF3, -CH3, and -H. In addition, the fitting analyses of the neutron reflectivity profiles of the thin polymer films in contact with air and water revealed the lowest affinity between water and the surface of polymethacrylate films with -SF5 groups among the films of the synthesized polymers. Thus, we demonstrated the potential of pentafluorosulfanyl groups as advanced hydrophobic groups.
RESUMEN
BACKGROUND: Transcranial static magnetic field stimulation (tSMS) using a small and strong neodymium (NdFeB) magnet can temporarily suppress brain functions below the magnet. It is a promising non-invasive brain stimulation modality because of its competitive advantages such as safety, simplicity, and low-cost. However, current tSMS is insufficient to effectively stimulate deep brain areas due to attenuation of the magnetic field with the distance from the magnet. The aim of this study was to develop a brand-new tSMS system for non-invasive deep brain stimulation. METHODS: We designed and fabricated a triple tSMS system with three cylindrical NdFeB magnets placed close to each other. We compared the strength of magnetic field produced by the triple tSMS system with that by the current tSMS. Furthermore, to confirm its function, we stimulated the primary motor area in 17 healthy subjects with the triple tSMS for 20 min and assessed the cortical excitability using the motor evoked potential (MEP) obtained by transcranial magnetic stimulation. RESULTS: Our triple tSMS system produced the magnetic field sufficient for neuromodulation up to 80 mm depth from the magnet surface, which was 30 mm deeper than the current tSMS system. In the stimulation experiment, the triple tSMS significantly reduced the MEP amplitude, demonstrating a successful inhibition of the M1 excitability in healthy subjects. CONCLUSION: Our triple tSMS system has an ability to produce an effective magnetic field in deep areas and to modulate the brain functions. It can be used for non-invasive deep brain stimulation.
Asunto(s)
Estimulación Encefálica Profunda , Estimulación Magnética Transcraneal , Humanos , Voluntarios Sanos , Potenciales Evocados Motores , Campos MagnéticosRESUMEN
The anisotropic microstructure of bone, composed of collagen fibers and biological apatite crystallites, is an important determinant of its mechanical properties. Recent studies have revealed that the preferential orientation of collagen/apatite composites is closely related to the direction and magnitude of in vivo principal stress. However, the mechanism of alteration in the collagen/apatite microstructure to adapt to the mechanical environment remains unclear. In this study, we established a novel ex vivo bone culture system using embryonic mouse femurs, which enabled artificial control of the mechanical environment. The mineralized femur length significantly increased following cultivation; uniaxial mechanical loading promoted chondrocyte hypertrophy in the growth plates of embryonic mouse femurs. Compressive mechanical loading using the ex vivo bone culture system induced a higher anisotropic microstructure than that observed in the unloaded femur. Osteocytes in the anisotropic bone microstructure were elongated and aligned along the long axis of the femur, which corresponded to the principal loading direction. The ex vivo uniaxial mechanical loading successfully induced the formation of an oriented collagen/apatite microstructure via osteocyte mechano-sensation in a manner quite similar to the in vivo environment.
Asunto(s)
Apatitas , Huesos , Animales , Apatitas/química , Colágeno/química , Fémur , Ratones , Osteocitos , Estrés MecánicoRESUMEN
Owing to issues, such as the depletion of petroleum resources and price instability, the development of biorefinery related technologies that produce fuels, electric power, chemical substances, among others, from renewable resources is being actively promoted. 2,3-Butanediol (2,3-BDO) is a key compound that can be used to produce various chemical substances. In recent years, 2,3-BDO production using biological processes has attracted extensive attention for achieving a sustainable society through the production of useful compounds from renewable resources. With the development of genetic engineering, metabolic engineering, synthetic biology, and other research field, studies on 2,3-BDO production by the yeast, Saccharomyces cerevisiae, which is safe and can be fabricated using an established industrial-scale cultivation technology, have been actively conducted. In this review, we sought to describe 2,3-BDO and its derivatives; discuss 2,3-BDO production by microorganisms, in particular S. cerevisiae, whose research and development has made remarkable progress; describe a method for separating and recovering 2,3-BDO from a microbial culture medium; and propose future prospects for the industrial production of 2,3-BDO by microorganisms.
Asunto(s)
Bioingeniería/métodos , Butileno Glicoles/metabolismo , Saccharomyces cerevisiae/metabolismo , Técnicas de Cultivo Celular por Lotes , Medios de Cultivo , Escherichia coli/genética , Escherichia coli/metabolismo , Etanol , Fermentación , Regulación de la Expresión Génica , Ingeniería Metabólica/métodos , Redes y Vías Metabólicas , Recombinación Genética , Saccharomyces cerevisiae/genéticaRESUMEN
Direct extraction and ionization techniques using minute amounts of solvent can be employed for the rapid analysis of chemical components in a sample without any sample preparation steps. This type of approach is important for mass spectrometry imaging of samples with multiple chemical components that have different spatial distributions (i.e., biological tissues). To improve the spatial resolution of such imaging, it is necessary to reduce the solvent volume for extraction and deliver it to the sample surface. This report describes a feedback control system applied to tapping-mode scanning probe electrospray ionization. By combining the measurement technique of capillary probe vibration with the dynamic distance control system between the probe and the sample, the vibration amplitude of the probe is maintained while the probe scans over uneven samples. This method allows simultaneous high-resolution imaging of molecular distribution, surface topography, and amplitude/phase changes in the probe vibration. Such multimodal imaging is demonstrated on rhodamine B thin films in microwells and on a mouse brain tissue section. This technique can generally be applied to examine the multidimensional molecular distribution and the surface profiles of various objects.
RESUMEN
A series of (E)-α-silyl-ß-alkoxyvinyl-λ3-iodanes was synthesized from iodosylbenzene, BF3-ether complexes, and terminal ethynylsilanes. The combined use of BF3-OiPr2 and benzyl ethers of primary alcohols (ROBn) allows the chemoselective transfer of primary alkoxy groups (RO) onto the ß-position of the terminal ethynylsilanes.
RESUMEN
Much research has been conducted on fabricating biomimetic biomaterials in vitro. Tissue engineering approaches are often conducted by combining cells, scaffolds, and growth factors. However, the degradation rate of scaffolds is difficult to control and the degradation byproducts occasionally limit tissue regeneration. To overcome these issues, we have developed a novel system using a thermo-responsive hydrogel that forms scaffold-free, three-dimensional (3D) cell constructs with arbitrary size and morphology. 3D cell constructs prepared using bone marrow-derived stromal stem cells (BMSCs) exhibited self-organizing ability and formed bone-like tissue with endochondral ossification. Endothelial cells were then introduced into the BMSC construct and a vessel-like structure was formed within the constructs. Additionally, the bone formation ability was promoted by endothelial cells and cell constructs could be freeze-dried to improve their clinical application. A pre-treatment with specific protein protectant allowed for the fabrication of novel bone substitutes composed only of cells. This 3D cell construct technology using thermo-responsive hydrogels was then applied to other cell species. Cell constructs composed of dental pulp stem cells were fabricated, and the resulting construct regenerated pulp-like tissue within a human pulpless tooth. In this review, we demonstrate the approaches for the in vitro fabrication of bone and dental pulp-like tissue using thermo-responsive hydrogels and their potential applications.