Radiation-induced Bystander Effects on Glioblastoma Tumor Cells via NMDA Receptor Signaling.

Proton therapy has been widely applied on treating inaccessible and inoperable tumors, such as tumors deep within the brain or close to the critical brain stem. Nevertheless, the damaging effect of radiation for central nervous system (CNS) tumors is difficult to be confined within the irradiated region and has led to decline of neurological function in especially children with congenital CNS tumors. Currently, the involvement of n-methyl-d-aspartate (NMDA) receptors or secretary cytokines and chemokines in proton-induced bystander effects remains unclear. To understand the modulatory effects of NMDA receptor inhibition on the survival and proliferation of glioblastoma-derived cells, mesenchymal-like U373 cells were applied along with U87 neural glioblastoma cells for single doses of proton radiation at different LET in the presence or absence of pretreatment with memantine and/or collimation. Under collimation, neuronal tumor cells that are not directly irradiated (i.e., bystander cells) encounter similar biological effects potentially through cell coupling and synaptic transmission. Furthermore, whether proton LET plays a role in the mediation of bystander effect awaits to be elucidated. From this study, synaptic transmission was found to play differential roles in the proliferation of U373 and U87 cells after exposure to collimated radiation. Also, radiation-induced cell proliferation at the late stage was more correlated with bystander cell survival than early manifested γH2AX foci, suggesting that proton-induced glutamatergic synapse may act as a more important contributor than proton-induced direct effect on DNA double-stranded breaks to the late-stage responses of glioblastoma cells.

Clinical Effect of Moisturized Skin Care on Radiation Dermatitis of Head and Neck Cancer.

BACKGROUND/AIM: Radiation therapy (RT) for head and neck cancer may cause severe radiation dermatitis (RD) resulting in RT interruption and affecting disease control. A few studies address skin moisture changes during RT for head and neck cancer. The purpose of this study was to explore the effect of moisturized skin care (MSC) on severity of RD. PATIENTS AND METHODS: The study includes newly diagnosed head and neck cancer patients undergoing RT. Participants were divided into MSC group and routine skin care (RSC) group based on patient's preferred decision. Skin moisture in the four quadrants of the neck was measured weekly before and after RT. RD was assessed with the Radiation Induced Skin Reaction Assessment Scale (RISRAS) and the Radiation Therapy Oncology Group (RTOG) acute skin toxicity grading criteria. RESULTS: A total of 54 patients were enrolled, of which 49 patients were suitable for the statistical analysis. There was a statistically significant difference in the RISRAS total score since the 5th week after RT between the groups. The severity of RD was less (B=0.814, p=0.021) and the onset was later (B=-0.384, p=0.006) in the MSC group when compared to the RSC group. Skin moisture decreased with cumulative radiation dose. In the upper neck, the MSC group had a slower rate of skin moisture decrease compared to the RSC group (right upper neck: B=0.935, p=0.007; left upper neck: B=0.93, p=0.018). CONCLUSION: MSC can effectively reduce the severity and delay the onset of RD, while slows down skin moisture decrease during RT.

Sources of Calcium at Connexin 36 Gap Junctions in the Retina.

Synaptic plasticity is a fundamental feature of the CNS that controls the magnitude of signal transmission between communicating cells. Many electrical synapses exhibit substantial plasticity that modulates the degree of coupling within groups of neurons, alters the fidelity of signal transmission, or even reconfigures functional circuits. In several known examples, such plasticity depends on calcium and is associated with neuronal activity. Calcium-driven signaling is known to promote potentiation of electrical synapses in fish Mauthner cells, mammalian retinal AII amacrine cells, and inferior olive neurons, and to promote depression in thalamic reticular neurons. To measure local calcium dynamics in situ, we developed a transgenic mouse expressing a GCaMP calcium biosensor fused to Connexin 36 (Cx36) at electrical synapses. We examined the sources of calcium for activity-dependent plasticity in retina slices using confocal or Super-Resolution Radial Fluctuations imaging. More than half of Cx36-GCaMP gap junctions responded to puffs of glutamate with transient increases in fluorescence. The responses were strongly dependent on NMDA receptors, in keeping with known activity-dependent signaling in some amacrine cells. We also found that some responses depended on the activity of voltage-gated calcium channels, representing a previously unrecognized source of calcium to control retinal electrical synaptic plasticity. The high prevalence of calcium signals at electrical synapses in response to glutamate application indicates that a large fraction of electrical synapses has the potential to be regulated by neuronal activity. This provides a means to tune circuit connectivity dynamically based on local activity.

Magnolol Suppresses ERK/NF-κB Signaling and Triggers Apoptosis Through Extrinsic/Intrinsic Pathways in Osteosarcoma.

BACKGROUND/AIM: Osteosarcoma is an aggressive primary malignant bone tumor that occurs in childhood. Although the diagnostic and treatment options have been improved, osteosarcoma confers poor prognosis. Magnolol, an active component of Magnoliae officinalis cortex, has been widely applied in herb medicine and has been shown to have multiple pharmacological activities. However, whether magnolol possesses anti-osteosarcoma capacity remains unknown. MATERIALS AND METHODS: We examined magnolol is cytotoxicity, and whether it regulates apoptosis and oncogene expression using MTT, flow cytometry and Western blotting assays in osteosarcoma cells. RESULTS: Magnolol exerted toxicity towards U-2 OS cells by inducing intrinsic/extrinsic apoptosis pathways. Additionally, treatment of U-2 OS cells with magnolol inhibited MAPK1 mitogen-activated protein kinase 1 (ERK)/Nuclear factor kappa B (NF-B) signaling involved in tumor progression and reduced the expression of anti-apoptotic and metastasis-associated genes. CONCLUSION: Magnolol may induce apoptosis and inactivate ERK/NF-B signal transduction in osteosarcoma cells.

Regorafenib enhances antitumor immune efficacy of anti-PD-L1 immunotherapy on oral squamous cell carcinoma.

Oral squamous cells carcinoma (OSCC) is the most common oral malignancy that majorly originated from oral cavity. Though the prognostic and predictive value of targeting checkpoint molecules has been reported on OSCC, the treatment efficacy of monotherapy is remaining limited. Several studies suggested that multikinase inhibitors may show potential to facilitate anti-PD-L1-induced anti-tumor immunity. Regorafenib, an oral multikinase inhibitor has been approved by FDA for various types of cancer treatment. Here, we aim to identify whether regorafenib may boost anti-tumor immunity of anti-PD-L1 in MOC1-bearing OSCC animal model. The alteration of immune cells such as M1/M2-like macrophages (MΦ), cytotoxicity T cells, regulatory T cells (Tregs), and myeloid-derived suppressor cells (MDSCs) after combination of anti-PD-L1 and regorafenib was validated by flow cytometry and immunohistochemistry staining. The combination index analysis (CI=0.89) supported that regorafenib effectively induce anti-OSCC efficacy of anti-PD-L1. Combination of anti-PD-L1 and regorafenib may not only trigger the polarization of M1-like MΦ (CD11b+CD86+) in mice bone marrow (BM) and spleen (SP), but also induce the accumulation and function of CD8+ T cells in tumor-draining lymph node (TDLN) and tumor. In addition, immunosuppressive related cells (MDSCs and Treg) and factors were all decreased by combination therapy in BM, SP and tumor. In sum, regorafenib may improve anti-OSCC efficacy of anti-PD-L1 through systemically and locally upregulating the immunostimulation immunity and suppressing immunosuppression immunity.

Revealing the suppressive role of protein kinase C delta and p38 mitogen-activated protein kinase (MAPK)/NF-κB axis associates with lenvatinib-inhibited progression in hepatocellular carcinoma in vitro and in vivo.

Nuclear factor-kappa B (NF-κB), an oncogenic transcription factor, modulates tumor formation and progression by inducing the expression of oncogenes involved in proliferation, survival, angiogenesis, and metastasis. Oral multikinase inhibitors, such as sorafenib, regorafenib, and lenvatinib have been used for the treatment of hepatocellular carcinoma (HCC). Both sorafenib and regorafenib were shown to abolish the NF-κB-mediated progression of HCC. However, the effect of lenvatinib on NF-κB-mediated progression of HCC is ambiguous. Therefore, the primary purpose of the present study was to evaluate the inhibitory effect of lenvatinib and its inhibitory mechanism on the NF-κB-mediated progression of HCC in vitro and in vivo. Here, we used two HCC cell lines to identify the cytotoxicity, apoptosis and metastasis effect of lenvatinib. We also applied a Hep3B-bearing animal model to investigate the therapeutic efficacy of lenvatinib on in vivo model. An NF-κB translocation assay, NF-κB reporter gene assay, a Western blotting assay and immunohistochemistry staining were used to investigate the underlying mechanism by which lenvatinib acts on HCC. In this study, we demonstrated that lenvatinib induced extrinsic/intrinsic apoptosis and suppressed the metastasis of HCC both in vitro and in vivo. Lenvatinib may also suppress NF-κB translocation and activation. We also found both protein kinase C delta (PKC-δ) and p38 mitogen-activated protein kinase (MAPK) inactivation participated in lenvatinib-reduced NF-κB signaling. In conclusion, this study reveals that the suppression of PKC-δ, and the p38 MAPK/NF-κB axis is associated with the lenvatinib-inhibited progression of HCC in vitro and in vivo.

Magnolol Induces the Extrinsic/Intrinsic Apoptosis Pathways and Inhibits STAT3 Signaling-Mediated Invasion of Glioblastoma Cells.

Glioblastoma multiforme (GBM) is the most common form of malignant brain tumor, with poor prognosis; the efficacy of current standard therapy for GBM remains unsatisfactory. Magnolol, an herbal medicine from Magnolia officinalis, exhibited anticancer properties against many types of cancers. However, whether magnolol suppresses GBM progression as well as its underlying mechanism awaits further investigation. In this study, we used the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay, apoptosis marker analysis, transwell invasion and wound-healing assays to identify the effects of magnolol on GBM cells. We also validated the potential targets of magnolol on GBM with the GEPIA (Gene Expression Profiling Interactive Analysis) and Western blotting assay. Magnolol was found to trigger cytotoxicity and activate extrinsic/intrinsic apoptosis pathways in GBM cells. Both caspase-8 and caspase-9 were activated by magnolol. In addition, GEPIA data indicated the PKCδ (Protein kinase C delta)/STAT3 (Signal transducer and activator of transcription 3) signaling pathway as a potential target of GBM. Magnolol effectively suppressed the phosphorylation and nuclear translocation of STAT3 in GBM cells. Meanwhile, tumor invasion and migration ability and the associated genes, including MMP-9 (Matrix metalloproteinase-9) and uPA (Urokinase-type plasminogen activator), were all diminished by treatment with magnolol. Taken together, our results suggest that magnolol-induced anti-GBM effect may be associated with the inactivation of PKCδ/STAT3 signaling transduction.

Suppression of EGFR/PKC-δ/NF-κB Signaling Associated With Imipramine-Inhibited Progression of Non-Small Cell Lung Cancer.

BACKGROUND: Anti-depressants have been reported to own anti-tumor potential types of cancers; however, the role of imipramine in non-small cell lung cancer (NSCLC) has not been elucidated. Epidermal growth factor receptor (EGFR) was known to be one of the key regulators that control NSCLC progression. Whether EGFR would be the target of imipramine for suppressing tumor signaling transduction and results in anti-tumor potential is remaining unclear. METHODS: We used CL-1-5-F4 cells and animal models to identify the underlying mechanism and therapeutic efficacy of imipramine. Cytotoxicity, apoptosis, invasion/migration, DNA damage, nuclear translocation of NF-κB, activation of NF-κB, phosphorylation of EGFR/PKC-δ/NF-κB was assayed by MTT, flow cytometry, transwell, wound healing assay, comet assay, immunofluorescence staining, NF-κB reporter gene assay and Western blotting, respectively. Tumor growth was validated by CL-1-5-F4/NF-κB-luc2 bearing animal model. RESULTS: Imipramine effectively induces apoptosis of NSCLC cells via both intrinsic and extrinsic apoptosis signaling. DNA damage was increased, while, invasion and migration potential of NSCLC cells was suppressed by imipramine. The phosphorylation of EGFR/PKC-δ/NF-κB and their downstream proteins were all decreased by imipramine. Similar tumor growth inhibition was found in imipramine with standard therapy erlotinib (EGFR inhibitor). Non-obvious body weight loss and liver pathology change were found in imipramine treatment mice. CONCLUSION: Imipramine-triggered anti-NSCLC effects in both in vitro and in vivo model are at least partially attributed to its suppression of EGFR/PKC-δ/NF-κB pathway.

Bismuth breast-shield use in chest computed tomography for efficient dose reduction and sufficient image quality.

BACKGROUND: Radiosensitivity in the breasts increases the risk of carcinogenesis from exposure to the ionizing radiation of computed tomography (CT) administered in the course of medical attention. Bismuth shielding techniques have been used to reduce radiation, but image noise increased, degrading image quality. PURPOSE: The aim of this study was to investigate how the use of iterative reconstruction (IR) combined with bismuth shielding influences image quality. MATERIALS AND METHODS: Women aged at least 20 years with body mass indexes <28 were recruited and randomly assigned to 1 of 3 CT scanning protocols without shielding, with a bismuth breast shield before the scout view, or with a bismuth breast shield after the scout view. All obtained images were reconstructed using an IR algorithm. To evaluate radiation dose, 2 Gafchromic films were placed over the clothes, 1 near each nipple. RESULTS: Average dose reduction was significant (27.99%, P < .05) when bismuth shielding was applied after the scout view. Using the contrast-to-noise ratio, the image quality was found to be superior when the IR algorithm was applied. Using quantitative evaluations by 2 radiologists applying a 4-point Likert scale, significant differences in image quality were not found among the 3 protocols. CONCLUSION: Bismuth breast shields, particularly when used after acquiring scout images, are effective at reducing radiation dose without undermining the diagnostic value of the images when the IR technique is applied.

Anticancer Efficacy and Mechanism of Amentoflavone for Sensitizing Oral Squamous Cell Carcinoma to Cisplatin.

BACKGROUND/AIM: Nuclear factor kappa B (NF-κB) inactivation and apoptosis activation have been shown to enhance the anticancer effect of cisplatin in oral squamous cell carcinoma (OSCC). Amentoflavone may suppress NF-κB activity and trigger apoptosis in different types of cancer. The aim of this study was to investigate the anticancer effect and mechanism of amentoflavone in combination with cisplatin in OSCC. MATERIALS AND METHODS: We investigated the combination effect and mechanism of amentoflavone and cisplatin via cell viability analysis, flow cytometry-based apoptosis analyses, transwell migration/invasion assay, immunofluorescence staining and western blotting assay. RESULTS: Both amentoflavone and QNZ (NF-κB inhibitor) significantly increased cisplatin-induced cytotoxicity. Amentoflavone reduced cisplatin-triggered NF-κB activity and enhanced cisplatin-induced intrinsic caspase-dependent and independent apoptotic pathways. Moreover, amentoflavone augments cisplatin-suppressed invasion and migration ability of OSCC cells. CONCLUSION: Inactivation of NF-κB and induction of apoptosis through intrinsic caspase-dependent and independent apoptotic pathways are associated with amentoflavone enhanced anti-OSCC efficacy of cisplatin.

Therapeutic Efficacy and Inhibitory Mechanism of Regorafenib Combined With Radiation in Colorectal Cancer.

BACKGROUND: Although both chemotherapy and radiotherapy (RT) can sufficiently maintain tumor suppression of colorectal cancer (CRC), these treatments may trigger the expression of nuclear factor kappa B (NF-κB) and compromise patients' survival. Regorafenib suppresses NF-κB activity in various tumor types. However, whether regorafenib may act as a suitable radiosensitizer to enhance therapeutic efficacy of RT remains unknown. MATERIALS AND METHODS: Here, we established a CRC-bearing animal model to investigate the therapeutic efficacy of regorafenib in combination with RT, through measurement of tumor growth, body weight, whole-body computed tomography (CT) scan and immunohisto-chemistry staining. RESULTS: Smallest tumor size and weight were found in the combination treatment group. In addition, RT-induced up-regulation of NF-κB and downstream proteins were diminished by regorafenib. Moreover, the body weight and liver pathology in the treated group were similar to those of the non-treated control group. CONCLUSION: Regorafenib may enhance the anti-CRC efficacy of RT.

Inter- and Intra-Rater Reliability of Individual Cerebral Blood Flow Measured by Quantitative Vessel-Flow Phase-Contrast MRI.

Vessel flow quantification by two-dimensional (2D) phase-contrast magnetic resonance imaging (PC-MRI) using a three-dimensional (3D) magnetic resonance angiography (MRA) model to measure cerebral blood flow has unclear analytical reliability. The present study aimed to determine the inter- and intra-rater reliability of quantitative vessel-flow PC-MRI and potential factors influencing its consistency. We prospectively recruited 30 Asian participants (aged 20-90 years; 16 women; 22 healthy and 8 stroke patients) for performing 1.5-T MR equipped with a head coil. Each participant was first scanned for time-of-flight magnetic resonance angiography (TOF-MRA) images for localization of intracranial arteries. The 2D PC-MRI for each cerebral artery (total 13 arteries in fixed order) was performed twice by two well-trained operators in optimal position. Using the same 3D MRA as a map and facilitated with the non-invasive optimal vessel analysis (NOVA) system, each scan was taken on a plane perpendicular to the target artery. Two consecutive full 13-artery scans were performed at least 15 min apart after participants were removed from the scanner table and then repositioned. A total of four PC flow images obtained from each target artery were transmitted to a workstation facilitated with the NOVA system. Flow data were calculated semi-automatically by the NOVA system after a few simple steps. Two-way mixed-effect models and standard errors of measurements were used. In 13 cerebral arteries, repeatability, using the intra-rater estimate expressed as the average-measures intraclass correlation coefficient, ranged from 0.641 to 0.954, and reproducibility, using the inter-rater estimate, ranged from 0.672 to 0.977. Except in the middle cerebral artery and the distal segment of the anterior cerebral artery, repeatability and reproducibility were excellent (intraclass correlation coefficient exceeded 0.8). The use of quantitative vessel-flow PC-MRI is a precise means to measure blood flow in most target cerebral arteries. This was evidenced by inter-rater and intra-rater correlations that were good/excellent, indicating good reproducibility and repeatability.

Consensus survey on pre-procedural safety practices in radiological examinations: a multicenter study in seven Asian regions.

OBJECTIVE: To understand the status of pre-procedural safety practices in radiological examinations at radiology residency training institutions in various Asian regions. METHODS: A questionnaire based on the Joint Commission International Accreditation Standards was electronically sent to 3 institutions each in 10 geographical regions across 9 Asian countries. Questions addressing 45 practices were divided into 3 categories. A five-tier scale with numerical scores was used to evaluate safety practices in each institution. Responses obtained from three institutions in the United States were used to validate the execution rate of each surveyed safety practice. RESULTS: The institutional response rate was 70.0% (7 Asian regions, 21 institutions). 44 practices (all those surveyed except for the application of wrist tags for identifying patients with fall risks) were validated using the US participants. Overall, the Asian participants reached a consensus on 89% of the safety practices. Comparatively, most Asian participants did not routinely perform three pre-procedural practices in the examination appropriateness topic. CONCLUSION: Based on the responses from 21 participating Asian institutions, most routinely perform standard practices during radiological examinations except when it comes to examination appropriateness. This study can provide direction for safety policymakers scrutinizing and improving regional standards of care. ADVANCES IN KNOWLEDGE: This is the first multicenter survey study to elucidate pre-procedural safety practices in radiological examinations in seven Asian regions.

Localized Calcium Signaling and the Control of Coupling at Cx36 Gap Junctions.

A variety of electrical synapses are capable of activity-dependent plasticity, including both activity-dependent potentiation and activity-dependent depression. In several types of neurons, activity-dependent electrical synapse plasticity depends on changes in the local Ca2+ environment. To enable study of local Ca2+ signaling that regulates plasticity, we developed a GCaMP Ca2+ biosensor fused to the electrical synapse protein Connexin 36 (Cx36). Cx36-GCaMP transfected into mammalian cell cultures formed gap junctions at cell-cell boundaries and supported Neurobiotin tracer coupling that was regulated by protein kinase A signaling in the same way as Cx36. Cx36-GCaMP gap junctions robustly reported local Ca2+ increases in response to addition of a Ca2+ ionophore with increases in fluorescence that recovered during washout. Recovery was strongly dependent on Na+-Ca2+ exchange activity. In cells transfected with NMDA receptor subunits, Cx36-GCaMP revealed transient and concentration-dependent increases in local Ca2+ on brief application of glutamate. In HeLa cells, glutamate application increased Cx36-GCaMP tracer coupling through a mechanism that depended in part on Ca2+, calmodulin-dependent protein kinase II (CaMKII) activity. This potentiation of coupling did not require exogenous expression of glutamate receptors, but could be accomplished by endogenously expressed glutamate receptors with pharmacological characteristics reminiscent of NMDA and kainate receptors. Analysis of RNA Sequencing data from HeLa cells confirmed expression of NMDA receptor subunits NR1, NR2C, and NR3B. In summary, Cx36-GCaMP is an effective tool to measure changes in the Ca2+ microenvironment around Cx36 gap junctions. Furthermore, HeLa cells can serve as a model system to study glutamate receptor-driven potentiation of electrical synapses.

Eye Shielding During Head CT Scans: Dose Reduction and Image Quality Evaluation.

RATIONALE AND OBJECTIVES: In this study, we assessed the radiation dose to the lens and the impacts of various eye shields using either a fixed or modulated tube current. MATERIALS AND METHODS: Patients undergoing head computed tomography (CT) examinations were recruited, and each was randomly assigned to one of five imaging groups, either without a CT eye shield or with one of two types of shielding and topogram-based tube current modulation (TCM). The radiation dose at the eye lens was estimated using Gafchromic films. All CT images were analyzed for quality in the orbit and brain areas. Two radiologists also qualitatively assessed image artifacts and their impacts on image quality using three-point Likert scales. RESULTS: Both barium sulfate and bismuth-antimony shields significantly reduced radiation dose to the lens (by 28.60%-31.92% and 43.87%-47.00%, respectively) while significantly inducing image artifacts. The image quality of the intraocular structure, but not the intracranial structure, was significantly degraded by shielding. In addition, discriminating the periocular tissues was improved using a bismuth-antimony shield and topogram-based TCM. Compared to fixed tube current, topogram-based TCM provided better signal-to-noise and contrast-to-noise ratios in the intracranial structures when the bismuth-antimony and barium sulfate shields were applied, respectively. CONCLUSION: Artifacts resulting from the application of eye shields during head CT examinations can be reduced by using topogram-based TCM instead of a fixed tube current. This could be an alternative approach for maintaining image quality in CT scans that do not encompass organ-based TCM.

Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding.

BACKGROUND: Multiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification. PURPOSE: To investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging. MATERIAL AND METHODS: An anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale. RESULTS: The estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shields were used in conjunction with a fixed tube current (22.0% and 35.6% reduction, respectively). Topogram-based TCM mitigated the beam hardening-associated artifacts of bismuth-antimony and barium sulfate shields. This increased the SNR by 21.6% in the extraorbital region and the CNR by 7.2% between the nasal bones and extraorbital regions. The combination of topogram-based TCM and barium sulfate or bismuth-antimony shields reduced lens doses by 12.2% and 27.2%, respectively. CONCLUSION: Image artifacts induced by the bismuth-antimony shield at a fixed tube current for lenticular radioprotection were significantly reduced by topogram-based TCM, which increased the SNR of the anthropomorphic nasal bones and periorbital tissues.

Calcium Imaging with Super-Resolution Radial Fluctuations.

Calcium signals act as a ubiquitous secondary messenger in regulating many body functions. The detection of calcium microdomain signals is greatly facilitated by the existence of biomarker-targeted fluorescent probes. In this study, SRRF (super-resolution radial fluctuations) algorithm were used to compare the loci and the intensity of fluorescent probes before and after SRRF analysis. The implementation of SRRF algorithm was aimed for automatically resolving delicate and small calcium signals (to avoid the overlapped loci) on original images. For assessing the spatial accuracy of image intensity, immunofluorescence staining of retina cryostat slice for connexin 36 (Cx36) was microscopically imaged with or without the successive SRRF reconstruction. For characterizing the temporal association between SRRF and non-SRRF images, the changes of Cx36-GCaMP calcium indicator were recorded from transfected HeLa cells in response to the transient puffing of ionomycin. Image processing and analyses were conducted with Image J and Matlab. Through this study, SRRF reconstruction was found to confer an accurate measure for the identification of subcellular molecules, such as gap junctions. Compared with the conventional imaging, SRRF reconstruction generated better image resolution for the precise registration of individual signals. Temporally, the ratios of change in fluorescence intensity between SRRF and non-SRRF images were significantly correlated in the presence or absence of the subtraction of high background intensity. Quantitatively, the ratios of change in fluorescence intensity between SRRF and non-SRRF images with or without background subtraction were also significantly correlated. The merit of SRRF application on calcium live imaging was validated with the reporter gene system we worked on.

Modulating mitochondrial morphology enhances antitumor effect of 5-ALA-mediated photodynamic therapy both in vitro and in vivo.

5-aminolevulinic acid mediated PDT (5-ALA-PDT) is an approved therapeutic procedure for treating carcinomas of the cervix. However, when employed as a monotherapy, 5-ALA-PDT could not produce satisfactory results toward large and deep tumors. Therefore, developing a method to improve the efficacy of 5-ALA-PDT becomes important. In this study, we demonstrate an enhanced antitumor effect of 5-ALA-PDT by the modulation of mitochondrial morphology. The mitochondria in the cells were regulated into tubular mitochondria or fragmented mitochondria through over expression of Drp1 or Mfn2. Then these cells were treated with identical dose of 5-ALA-PDT. Our results suggest that HeLa cells predominantly containing fragmented mitochondria were more sensitive to 5-ALA-PDT than the cells predominantly containing tubular mitochondria. The morphology of mitochondria changed as the cell cycle progressed, with tubular mitochondria predominantly exhibited in the S phase and uniformly fragmented mitochondria predominantly displayed in the M phase. Paclitaxel significantly increased the population of M-phase cells, while 5-fluorouracil significantly increased the population of S-phase cells in xenograft tumors. Furthermore, low-dose paclitaxel significantly increased the antitumor effects of PDT. However, 5-fluorouracil didn't improve the antitumor effects of PDT. These results demonstrated an enhanced antitumor effect of 5-ALA-PDT from the modulation of mitochondrial morphology. We anticipate that our results will provide an insight for selecting potential chemotherapeutic agents to combine with PDT for tumor treatment.

Reproducibility and Repeatability of Computer Tomography-based Measurement of Abdominal Subcutaneous and Visceral Adipose Tissues.

Excessive accumulation of abdominal adipose tissue is a widely recognized as a major feature of obesity, and it can be quantified by dual-energy x-ray absorptiometry (DXA). However, in a phantom study, the inter- and intra-instrument reliability of DXA remains unpredictable. Thus, we attempted to determine the precision of estimates from computer tomography-based measurements and analysis with AZE Virtual Place software. To determine the inter-rater reproducibility and intra-rater repeatability of adipose tissue area estimates, we used the automatic boundary-tracing function of the AZE Virtual Place to generate cross-sectional areas of subcutaneous and visceral adipose tissues from the abdomen of reconstructed CT images. The variability of inter-rater and intra-rater estimates expressed as the coefficient of variation ranged from 0.47% to 1.43% for subcutaneous adipose tissue and 1.08% to 2.20% for visceral adipose tissue; the optimal coefficient of variation of the fat rate calculation ranged from 0.55% to 1.13%, respectively. There was high and significant correlation between adipose tissue areas as estimated in 40 obese subjects by two raters or repeatedly on 20 obese subjects by either rater. This indicates excellent reproducibility and repeatability via a computer tomography-based measurement of abdominal subcutaneous and visceral adipose tissues.

Assessment of radiation safety in cardiac CT angiography.

This study investigates the radiation dose and image quality of patients not receiving ß-blockers for cardiac CT angiography (CCTA) with or without the optimization of electrocardiographic (ECG) pulsing window. The differences in patient characteristics are also characterized.Normal-weight and obese patients (n = 154) with heart rates between 65 and 80 beats per minutes (bpm) during the prospective axial scanning were enrolled retrospectively. The ECG pulsing windows were set at 50% to 75% (Group A) or 60% to 75% (Group B) of the R-R interval for patients with heart rate variability higher than or not exceeding ±5 bpm, respectively. The effective doses of individual patient were estimated from the dose length product of the CCTA scan. Two radiologists independently reviewed the images and applied a 4-point Likert scale for image quality assessment. The patients' characteristics were compared along with the patients' effective doses between groups.The optimized pulsing window significantly reduced the average radiation dose for normal-weight and obese patients by 33% and 27%, respectively. The CCTA image quality of patients in Group A was not different overall from those obtained from Group B. Nondiabetic obese patients were more likely to be accepted for the use of the optimized pulsing window. Unlike obese patients, normal-weight patients revealed no characteristic difference between Groups A and B.This study indicates an equivalent efficacy of using optimized pulsing windows for reducing the radiation dose for patients without ß-blocker administration between different body weight groups. Nevertheless, gender and diabetic status became prominent characteristics in the obese group when matching up with the optimized pulsing window.