Nitrate formation mechanisms causing high concentration of PM2.5 in a residential city with low anthropogenic emissions during cold season.

During the cold season in South Korea, NO3- concentrations are known to significantly increase, often causing PM2.5 to exceed air quality standards. This study investigated the formation mechanisms of NO3- in a suburban area with low anthropogenic emissions. The average PM2.5 was 25.3 µg m-3, with NO3- identified as the largest contributor. Ammonium-rich conditions prevailed throughout the study period, coupled with low atmospheric temperature facilitating the transfer of gaseous HNO3 into the particulate phase. This result indicates that the formation of HNO3 played a crucial role in determining particulate NO3- concentration. Nocturnal increases in NO3- were observed alongside increasing ozone (O3) and relative humidity (RH), emphasizing the significance of heterogeneous reactions involving N2O5. NO3- concentrations at the study site were notably higher than in Seoul, the upwind metropolitan area, during a high concentration episode. This difference could potentially attributed to lower local NO concentrations, which enhanced the reaction between O3 and NO2, to produce NO3 radicals. High concentrations of Cl- and dust were also identified as contributors to the elevated NO3- concentrations.

Cervical spine reconstruction after total vertebrectomy using customized three-dimensional-printed implants in dogs.

BACKGROUND: Sufficient surgical resection is necessary for effective tumor control, but is usually limited for vertebral tumors, especially in the cervical spine in small animal neurosurgery. OBJECTIVE: To evaluate the primary stability and safety of customized three-dimensional (3D)-printed implants for cervical spine reconstruction after total vertebrectomy. METHODS: Customized guides and implants were designed based on computed tomography (CT) imaging of five beagle cadavers and were 3D-printed. They were used to reconstruct C5 after total vertebrectomy. Postoperative CT images were obtained to evaluate the safety and accuracy of screw positioning. After harvesting 10 vertebral specimens (C3-C7) from intact (group A) and implanted spines (group B), implant stability was analyzed using a 4-point bending test comparing with groups A and C (reconstituted with plate and pins/polymethylmethacrylate after testing in Group A). RESULTS: All customized implants were applied without gross neurovascular damage. In addition, 90% of the screws were in a safe area, with 7.5% in grade 1 (< 1.3 mm) and 2.5% in grade 2 (> 1.3 mm). The mean entry point and angular deviations were 0.81 ± 0.43 mm and 6.50 ± 5.11°, respectively. Groups B and C significantly decreased the range of motion (ROM) in C3-C7 compared with intact spines (p = 0.033, and 0.018). Both groups reduced overall ROM and neutral zone in C4-C6, but only group B showed significance (p = 0.005, and 0.027). CONCLUSION: Customized 3D-printed implants could safely and accurately replace a cervical vertebra in dog cadavers while providing primary stability.

Three-dimensional-printed patient-specific guides for tibial deformity correction in small-breed dogs.

OBJECTIVE: To describe the use of patient-specific 3-D-printed osteotomy, reduction, and compression guides for tibial closing wedge osteotomy in small-breed dogs. ANIMALS: 6 dogs with unilateral tibial deformities. METHODS: Six small-breed dogs with 1 or a combination of tibial deformities, including excessive tibial plateau angle, valgus, and torsion, were scheduled to undergo tibial closing wedge osteotomy using patient-specific 3-D-printed osteotomy, reduction, and compression guides. The location and orientation of the wedge osteotomy were determined based on CT data using computer-aided design software. After the tibial deformities were corrected, postoperative CT or radiographs were obtained to compare the achieved tibial limb angles with the planned angles. Clinical evaluation and radiographic follow-up were performed on all dogs. RESULTS: Guides were successfully positioned at each specific location, and osteotomies were performed without radiation exposure or observer assistance in all dogs. Tibial deformities were corrected with angular errors of 1.8 ± 1.4°, 2.3 ± 2.1°, and 2.6 ± 1.3° in the sagittal, frontal, and transverse planes, respectively. Mild complications resolved within 1 month in 3 dogs, and revision surgery was not required. Five dogs improved to the normal gait (mean, 14.8 ± 6.6 weeks), and 1 dog recovered a satisfactory gait 24 weeks after surgery. All limbs healed 14 ± 4.7 weeks after surgery. CLINICAL RELEVANCE: Patient-specific 3-D-printed osteotomy, reduction, and compression guides can provide effective assistance allowing accurate correction of tibial deformities. Their use yields good clinical outcomes in small-breed dogs.

Ecdysone-induced microRNA miR-276a-3p controls developmental growth by targeting the insulin-like receptor in Drosophila.

Animal growth is controlled by a variety of external and internal factors during development. The steroid hormone ecdysone plays a critical role in insect development by regulating the expression of various genes. In this study, we found that fat body-specific expression of miR-276a, an ecdysone-responsive microRNA (miRNA), led to a decrease in the total mass of the larval fat body, resulting in significant growth reduction in Drosophila. Changes in miR-276a expression also affected the proliferation of Drosophila S2 cells. Furthermore, we found that the insulin-like receptor (InR) is a biologically relevant target gene regulated by miR-276a-3p. In addition, we found that miR-276a-3p is upregulated by the canonical ecdysone signalling pathway involving the ecdysone receptor and broad complex. A reduction in cell proliferation caused by ecdysone was compromised by blocking miR-276a-3p activity. Thus, our results suggest that miR-276a-3p is involved in ecdysone-mediated growth reduction by controlling InR expression in the insulin signalling pathway.

MicroRNA miR-252-5p regulates the Notch signaling pathway by targeting Rab6 in Drosophila wing development.

The Notch signaling pathway plays a central role in the development of various organisms. However, dysregulation of microRNAs (miRNAs), which are crucial regulators of gene expression, can disrupt signaling pathways at all stages of development. Although Notch signaling is involved in wing development in Drosophila, the mechanism underlying miRNA-based regulation of the Notch signaling pathway is unclear. Here, we report that loss of Drosophila miR-252 increases the size of adult wings, whereas the overexpression of miR-252 in specific compartments of larval wing discs leads to patterning defects in the adult wings. The miR-252 overexpression-induced wing phenotypes were caused by aberrant Notch signaling with intracellular accumulation of the full-length Notch receptor during development, which could be due to defects in intracellular Notch trafficking associated with its recycling to the plasma membrane and autophagy-mediated degradation. Moreover, we identified Rab6 as a direct target of miR-252-5p; Rab6 encodes a small Ras-like GTPase that regulates endosomal trafficking pathways. Consistent with this finding, RNAi-mediated downregulation of Rab6 led to similar defects in both wing patterning and Notch signaling. Notably, co-overexpression of Rab6 completely rescued the wing phenotype associated with miR-252 overexpression, further supporting that Rab6 is a biologically relevant target of miR-252-5p in the context of wing development. Thus, our data indicate that the miR-252-5p-Rab6 regulatory axis is involved in Drosophila wing development by controlling the Notch signaling pathway.

Impact of Lacrimal Gland Extraction on the Contralateral Eye in an Animal Model for Dry Eye Disease.

PURPOSE: Although there is still no consensus on the best animal model for dry eye disease research, a model based on lacrimal gland extraction (LGE) model is widely used. In this study, we aimed to investigate the histopathological changes taking place on the contralateral eye after unilateral LGE to determine whether it is useful as a control. METHODS: Seven-week-old male C57BL/6 mice were divided into naive control, environmental chamber model, and LGE groups. Corneal fluorescein staining was scored to quantify the severity of damage. Morphological changes in the cornea, conjunctiva, and lacrimal gland (LG) were determined by hematoxylin and eosin staining and compared to those on naive control animals. RESULTS: Compared to naive subjects, the unilateral LGE model showed enhanced corneal erosion scores and loss of conjunctival goblet cells, not only on the ipsilateral but also on the contralateral side. These changes in the ocular surface became more pronounced in a time-dependent manner. Furthermore, loss of LG acinar cells and leukocyte infiltration were detected in the contralateral LGs of the LGE model. CONCLUSIONS: Considering the changes observed in the ocular surface and LGs, the contralateral side of the LGE model may not offer proper control conditions for the experimental comparison of the effects of dry eye disease in vivo. There may be regulatory feedback or crosstalk system between both eyes activated in response to LGE.

Clinical and biological implications of CD133-positive and CD133-negative cells in glioblastomas.

A number of recent reports have demonstrated that only CD133-positive cancer cells of glioblastoma multiforme (GBM) have tumor-initiating potential. These findings raise an attractive hypothesis that GBMs can be cured by eradicating CD133-positive cancer stem cells (CSCs), which are a small portion of GBM cells. However, as GBMs are known to possess various genetic alterations, GBMs might harbor heterogeneous CSCs with different genetic alterations. Here, we compared the clinical characteristics of two GBM patient groups divided according to CD133-positive cell ratios. The CD133-low GBMs showed more invasive growth and gene expression profiles characteristic of mesenchymal or proliferative subtypes, whereas the CD133-high GBMs showed features of cortical and well-demarcated tumors and gene expressions typical of proneuronal subtype. Both CD133-positive and CD133-negative cells purified from four out of six GBM patients produced typical GBM tumor masses in NOD-SCID brains, whereas brain mass from CD133-negative cells showed more proliferative and angiogenic features compared to that from CD133-positive cells. Our results suggest, in contrast to previous reports that only CD133-positive cells of GBMs can initiate tumor formation in vivo CD133-negative cells also possess tumor-initiating potential, which is indicative of complexity in the identification of cancer cells for therapeutic targeting.

Antitumor activity of ZD6474 in a metastatic orthotopic brain tumor model.

The objective of this study was to examine the antitumor effect of ZD6474, an orally available inhibitor of the vascular endothelial growth factor receptor-2 (VEGFR-2) and the epidermal growth factor receptor (EGFR), on tumor growth in an orthotopic metastatic brain tumor model. In order to determine the antitumor mechanism of ZD6474 treatment, in vitro and in vivo studies were performed. Human breast carcinoma cells (MDA-MB-435) were injected using direct intracranial (IC) inoculation (5x105 cells/100 µl) and internal carotid artery (ICA) injection (5x104 cells/100 µl) in Balb/c-nu female mice. Daily oral treatment with ZD6474 (50 mg/kg) was initiated on day 14 after the establishment of micrometastasis. Mice (n=12 per group) were sacrificed on day 28. Western blot analysis revealed that the autophosphorylation of EGFR and Akt was increasingly decreased with ZD6474 treatment in lung and brain endothelial cells and the MDA-MB-435 cell line. MTT assay also showed that the in vitro antitumor activity of ZD6474 was dependent on EGFR tyrosine kinase inhibition at a higher dose. Daily oral treatment with ZD6474 led to marked inhibition of metastatic tumor growth in the ICA injection and the direct IC inoculation models (median size 3.5 mm3, range 1.6-13.9 mm3) as compared to the control group (median size 62.4 mm3, range 11.5-206.9 mm3). These results suggest that simultaneous inhibition of both the EGFR and VEGFR-2 signaling pathways has a valuable therapeutic effect through its inhibition of the growth of metastatic brain tumors.

Anti-angiogenic action of plasma hyaluronan binding protein in human umbilical vein endothelial cells.

The kringle domain is a triple loop structure present in angiostatin and endostatin. The disulfide bond-linked kringle architectures have been known to be essential for anti-angiogenic activity. Plasma hyaluronan binding protein (PHBP) is a novel serine protease which consists of three epidermal growth factor (EGF) domains, a kringle domain, and a serine protease domain. PHBP can be cleaved autocatalytically to generate activity and is highly expressed in the human blood and liver. To determine the anti-angiogenic activities of PHBP, we purified recombinant mouse PHBP from stable cell line overexpressing PHBP and used protein in vivo and in vitro angiogenesis assays. We found that recombinant PHBP inhibits not only angiogenesis in vivo in chorioallantoic membrane (CAM) assay but also the basic fibroblast growth factor (bFGF)-induced proliferation, invasion and tube formation of human umbilical vein endothelial cells (HUVECs) in a dose-dependant manner. Moreover, we found that the kringle domain of PHBP was essential for the anti-angiogenic action of PHBP by the deletion mutants. These findings unravel a new function of PHBP as an inhibitor of the proangiogenic phenotype of vascular endothelial cells and demonstrate that the kringle domain of PHBP might be a potent novel inhibitor of activated endothelial cells in vitro and in vivo.

Synergistic effect and condition of pegylated interferon alpha with paclitaxel on glioblastoma.

Glioblastomas are highly vascularized tumors and anti-angiogenic strategy is one of the most promising therapeutic approaches to treat brain tumors. Interferon alpha (IFN-alpha) as a single agent or combined with standard chemo-therapy has been shown to inhibit various tumors, but the effect of combination anti-angiogenic therapy on brain tumors has not been well studied. We determined the optimal dose and schedule of pegylated IFN-alpha (PEG-IFN-alpha) against U-87MG human glioblastoma cells growing orthotopically in nude mice, since several clinical trials reported that PEG-IFN-alpha administered at higher or lower doses was less effective. The group treated two times per week with injections of 10 KU of PEG-IFN-alpha for 4 weeks showed significant decreases in cell proliferation and angiogenesis. Moreover, the optimal dose and schedule of PEG-IFN-alpha determined in this study and combined with paclitaxel treatment potently inhibited tumor growth in vivo. The mechanisms of the significant therapeutic effects were most likely caused by directly inhibiting cell proliferation and angiogenesis, and rendering apoptosis increased. Specifically PEG-IFN-alpha/paclitaxel combination induced apoptosis of tumor-associated endothelial cells more than that of tumor cells. These results suggest that optimal biological dosage and scheduling of PEG-IFN-alpha and paclitaxel combination is a potent strategy for glioblastoma patients as a new synergistic anti-endothelial treatment.