Glioblastoma (GBM) is one of the most intractable tumor types due to the progressive drug resistance upon tumor mass expansion. Incremental hypoxia inside the growing tumor mass drives epigenetic drug resistance by activating nongenetic repair of antiapoptotic DNA, which could be impaired by drug treatment. Hence, rescuing intertumor hypoxia by oxygen-generating microparticles may promote susceptibility to antitumor drugs. Moreover, a tumor-on-a-chip model enables user-specified alternation of clinic-derived samples. This study utilizes patient-derived glioblastoma tissue to generate cell spheroids with size variations in a 3D microchannel network chip (GBM chip). As the spheroid size increases, epigenetic drug resistance is promoted with inward hypoxia severance, as supported by the spheroid size-proportional expression of hypoxia-inducible factor-1a in the chip. Loading antihypoxia microparticles onto the spheroid surface significantly reduces drug resistance by silencing the expression of critical epigenetic factor, resulting in significantly decreased cell invasiveness. The results are confirmed in vitro using cell line and patient samples in the chip as well as chip implantation into a hypoxic hindlimb ischemia model in mice, which is an unprecedented approach in the field.
Aims We developed a new rapid and reliable method for identifying bacteria using a combination of Fourier transform infrared (FT‐IR) spectroscopy of bacterial genomic DNA and multivariate analysis. Methods and Results FT‐IR spectra of genomic DNA from four type strains of Pseudomonas spp., three type strains of Escherichia spp. and two type strains of Bacillus spp. were analysed in the 4000–400 cm−1 region. Spectral differences were found in the frequency regions of N–H stretching (amide I), C=O stretching vibrations (amide II) and PO2− ionized asymmetric and symmetric stretching. Partial least squares discriminant analysis of the FT‐IR spectra showed that the microbial strains could be discriminated by hierarchical clustering analysis. Conclusions FT‐IR spectral analysis of bacterial genomic DNA has potential for the rapid identification of bacteria at the genus and species levels. Significance and Impact of the Study This study reports a new bacterial identification method using multivariate analysis of FT‐IR spectra of bacterial genomic DNA.
Histological analysis is widely used to evaluate injured tendons; however, it has the limitation of being semi‐quantitative. Hence, we developed a quantification method to objectively evaluate the fibrous structure of tendons, exhibiting the optical property of birefringence, using polarization‐sensitive optical coherence tomography (PS‐OCT). We used a partial‐rupture rat model in which the middle 0.75 cm of the Achilles tendon was cut with a blade. Rats were sacrificed at 2, 4 or 6 weeks after the injury, and PS‐OCT and histological analyzes were performed. The PS‐OCT phase retardation images and score well represented the structural changes of the injured tendon according to the wound healing state. Therefore, the proposed novel quantification method using PS‐OCT can be used to evaluate the fibrous structural status of tendons.
Histological analysis is widely used to evaluate injured tendons; however, it has the limitation of being semi‐quantitative. Hence, a quantification method to objectively evaluate the fibrous structure of tendons was developed with exhibiting the optical property of birefringence by using polarization‐sensitive optical coherence tomography (PS‐OCT). The phase retardation images was quantified according to the degree of repetition of the period. The obtained frequency value of the peak from the Fourier transform of the periodic pattern in the phase retardation image indicates the degree of the structural arrangement of collagen fibers. The better the arrangement of the collagen fibers results the higher the frequency values, and a disordered collagen fiber architecture results in a lower repetition frequency value. The scoring method well represented the fibrous structural changes of the injured Achilles tendon according to the wound healing state with a partial‐rupture rat model. Further details can be found in the article by Yong‐Jae Lee, Eunwoo Park, Kwan Seob Park, Jun‐Hyuk Lim, Sungmin Kim, Myung‐Sun Kim, and Tae Joong Eom (https://doi.org/10.1002/jbio.202200065).
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