Transmission Electron Microscopy (
            <scp>TEM</scp>
            )

Kikuchi, Jun‐ichi

doi:10.1002/9780470661345.smc022

Cited by 9 publications

(7 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Molecular gels with a wide range of morphologies including tapes, ribbons, fibers, and microcrystalline networks have been reported in the literature. − More importantly, self-assembly of chiral gelator molecules has also been shown to exhibit amplification of chirality upon gelation, ,− and in some cases, formation of helical fibers, twisted tapes, or ribbons has been visualized using electron microscopy (EM). , Molecular gels also display self-healing and thixotropic behavior making them attractive for industrial, pharmaceutical, and cosmetic applications. , Self-healing gels recover their initial properties, e.g., modulus or shape, after being subjected to physical, chemical, or mechanical perturbations. − Self-healing properties of molecular gels can be determined using visual demonstration, oscillatory rheology, and cyclic compression/tensile testing . While visual demonstration is a qualitative method, step-strain rheological experiments allow quantitative determination of structure recovery.…”

Section: Introductionmentioning

confidence: 99%

Rapid Self-Healing and Thixotropic Organogelation of Amphiphilic Oleanolic Acid–Spermine Conjugates

et al. 2021

View full text Add to dashboard Cite

Natural and abundant plant triterpenoids are attractive starting materials for the synthesis of conformationally rigid and chiral building blocks for functional soft materials. Here, we report the rational design of three oleanolic acid–triazole–spermine conjugates, containing either one or two spermine units in the target molecules, using the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction. The resulting amphiphile-like molecules 2 and 3, bearing just one spermine unit in the respective molecules, self-assemble into highly entangled fibrous networks leading to gelation at a concentration as low as 0.5% in alcoholic solvents. Using step-strain rheological measurements, we show rapid self-recovery (up to 96% of the initial storage modulus) and sol ⇔ gel transition under several cycles. Interestingly, rheological flow curves reveal the thixotropic behavior of the gels. To the best of our knowledge, this kind of behavior was not shown in the literature before, neither for a triterpenoid nor for its derivatives. Conjugate 4, having a bolaamphiphile-like structure, was found to be a nongelator. Our results indicate that the position and number of spermine units alter the gelation properties, gel strength, and their self-assembly behavior. Preliminary cytotoxicity studies of the target compounds 2–4 in four human cancer cell lines suggest that the position and number of spermine units affect the biological activity. Our results also encourage exploring other triterpenoids and their derivatives as sustainable, renewable, and biologically active building blocks for multifunctional soft organic nanomaterials.

show abstract

Section: Introductionmentioning

confidence: 99%

Rapid Self-Healing and Thixotropic Organogelation of Amphiphilic Oleanolic Acid–Spermine Conjugates

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Moreover, round-shaped vesicles of about 100 nm diameter were clearly observed by cryo-TEM ( Fig. 1C ), which enables the in situ visualization of vesicle structure in water [ 32 ]. These vesicles observed by TEM and cryo-TEM exhibited structures similar to those of exosomes in porcine breast milk and the follicular fluid of other mammalian species [ 9 , 10 , 33 ].…”

Section: Resultsmentioning

confidence: 99%

Effects of exosome-like vesicles on cumulus expansion in pigs <i>in vitro</i>

Matsuno

Onuma

Fujioka

et al. 2017

Journal of Reproduction and Development

Self Cite

View full text Add to dashboard Cite

Cell-secreted vesicles, such as exosomes, have recently been recognized as mediators of cell communication. A recent study in cattle showed the involvement of exosome-like vesicles in the control of cumulus expansion, a prerequisite process for normal ovulation; however, whether this is the case in other mammalian species is not known. Therefore, this study aimed to examine the presence of exosome-like vesicles in ovarian follicles and their effects on cumulus expansion in vitro in pigs. The presence of exosome-like vesicles in porcine follicular fluid (pFF) was confirmed by transmission electron microscopic observation, the detection of marker proteins, and RNA profiles specific to exosomes. Fluorescently labeled exosome-like vesicles isolated from pFF were incorporated into both cumulus and mural granulosa cells in vitro. Exosome-like vesicles were not capable of inducing cumulus expansion to a degree comparable to that induced by follicle-stimulating hormone (FSH). Moreover, exosome-like vesicles had no significant effects on the expression levels of transcripts required for the normal expansion process (HAS2, TNFAIP6, and PTGS2). Interestingly, FSH-induced expression of HAS2 and TNFAIP6 mRNA, but not of PTGS2 mRNA, was significantly increased by the presence of exosome-like vesicles; however, the degree of FSH-induced expansion was not affected. In addition, porcine exosome-like vesicles had no significant effects on the expansion of mouse cumulus-oocyte complexes. Collectively, the present results suggest that exosome-like vesicles are present in pFF, but they are not efficient in inducing cumulus expansion in pigs.

show abstract

“…TEM allows for the visualization of ultracellular structures of platelets. The platelet specimen is illuminated by an electron beam under high‐vacuum conditions; the resultant transmitted or diffracted beam magnifies the image up to a million times (Kikuchi & Yasuhara, 2012). The contrasted visualization of platelets' structure with the use of TEM is as a result of the differences in electron density of the platelet constituents (Kikuchi & Yasuhara, 2012).…”

Section: Methodsmentioning

confidence: 99%

“…TEM allowed for the morphological visualization of ultracellular structures of platelets of CML patient's and control participants (Kikuchi & Yasuhara, 2012). Figure 4 indicates the morphological structure of CML patient's platelets at time of diagnosis and Figure 5 shows CML patients' platelet structures after 6 months of treatment with Imatinib.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

Ex vivo platelet morphology assessment of chronic myeloid leukemia patients before and after Imatinib treatment

Repsold

Pool

Karodia

et al. 2022

Microscopy Res & Technique

View full text Add to dashboard Cite

Chronic myeloid leukemia (CML) is a myeloproliferative disease and the first line treatment is through the administration of Imatinib, a first generation tyrosine kinase inhibitor. Thrombocytosis and bleeding irregularities are common in CML, however, the morphological variations in CML patients' platelets are not well documented. In this study, ex vivo platelet morphology of control participants, as well as CML patients were assessed before and after Imatinib treatment. The topographical and structural morphology of platelets were determined via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Qualitative data of SEM and TEM revealed that CML patient's platelets were prone to aggregation and coagulation at time of diagnosis; the samples that were not aggregated at time of diagnosis showed typical discoid shaped platelets, which was comparable to control participants' platelets.TEM results of CML patients' platelets at diagnosis showed that internal granular constituents including dense bodies were decreased in comparison to control participants. In all CML patients, platelets appeared activated after 6 months of treatment with Imatinib with membrane structure abnormalities and constituent variations.Research to date has primarily focused on the effects of CML on leukocyte populations, however, the results of the current study implicate the impact of CML pathogenesis on platelets, seemingly as a result of alterations in normal hematopoiesis. In addition, the impact of Imatinib treatment on platelet morphology was also established, indicating an increase in platelet activation. Recognizing and understanding the impact of CML disease progression on platelets is of importance to aid improved patient treatment.

show abstract

Transmission Electron Microscopy ( TEM )

Cited by 9 publications

References 53 publications

Rapid Self-Healing and Thixotropic Organogelation of Amphiphilic Oleanolic Acid–Spermine Conjugates

Rapid Self-Healing and Thixotropic Organogelation of Amphiphilic Oleanolic Acid–Spermine Conjugates

Effects of exosome-like vesicles on cumulus expansion in pigs <i>in vitro</i>

Ex vivo platelet morphology assessment of chronic myeloid leukemia patients before and after Imatinib treatment

Contact Info

Product

Resources

About