Risk factors for internal carotid artery injury in adults during simple nasopharyngeal surgeries

The purpose of this study attempted to analyze the potential risk factors for internal carotid artery injury during simple nasopharyngeal surgeries with or without an endoscopic aid. One hundred and seventy magnetic resonance imaging scans (340 halves) of the brain were retrospectively reviewed and studied. Anatomic variations of carotid arteries were classified, and various distances from the internal carotid arteries to the nasopharyngeal subsites were directly measured on the scans. The mean distances between the internal carotid arteries and nasopharyngeal subsites were significantly shortened in patients with nasopharyngeal internal carotid artery aberrancy, female gender, and lower body weight. The distance to the posterior nasopharyngeal wall was also shortened with age. However, the severity of nasopharyngeal carotid artery variations (kinking and coiling) did not reflect the shortening of mean distances to nasopharyngeal subsites. In conclusion, from multiple linear regression analysis, we found that the risk of an internal carotid artery injury during simple nasopharyngeal surgeries with or without an endoscopic aid is greatest in adult patients with nasopharyngeal carotid artery aberrancy, followed by female gender, lower body weight, and increasing age.     

日达仙稀释液治疗肿瘤化疗后口腔溃疡的疗效观察

目的观察日达仙稀释液对化疗后口腔溃疡患者的治疗作用。方法选择住院化疗后并发口腔溃疡患者68名,随机分为治疗组及对照组,治疗组用日达仙液涂抹溃疡面,对照组用锡类散涂抹溃疡面,观察两组间口腔溃疡疗效的差异。结果治疗组患者平均溃疡治愈时间(4.87±0.96)d及平均疼痛指数(3.84±1.21)分均明显低于对照组,差异均有统计学意义(t分别=7.55、5.46,P均<0.05)。结论日达仙稀释液对患者化疗后并发的口腔溃疡有较好疗效。     

A microfluidic device mimicking acinar concentration gradients across the liver acinus

The acinus-mimicking microfluidic chip, which simulates the in vivo condition of the liver, was developed and reported in this paper. The gradient microenvironment of the liver acinus is replicated within this proposed microfluidic chip. The advantage of this acinus-mimicking chip is capable of adjusting the concentration gradient in a relatively short period of time at around 10 s. At the same instance the non-linear concentration gradient can be presented in the various zones within this microfluidic chip. The other advantage of this proposed design is in the convenience of allowing the direct injection of the cells into the chip. The environment within the chip is multi-welled and gel-free with high cell density. The multi-row pillar microstructure located at the entrance of the top and bottom flow channels is designed to be able to balance the pressure of the perfusion medium. Through this mechanism the shear stress experienced by the cultured cells can be minimized to reduce the potential damage flow from the perfusion process. ⁽³⁾The fluorescence staining and the observations of the cell morphology verify the life and death of the cells. The shear stress experienced by the cells in the various zones within the chip can be effectively mapped. The serum glutamic oxaloacetic transaminase (SGOT) collected from the supernatants was used to determine the effects of the degassing process and the shear stress of the medium flow on the cultured cells.     

Improvement of Oral Bioavailability and Anti-Tumor Effect of Zingerone Self-Microemulsion Drug Delivery System

This study sought to prepare a self-microemulsion drug delivery system containing zingerone (Z-SMEDDS) to improve the low oral bioavailability of zingerone and anti-tumor effect. Z-SMEDDS was characterized by particle size, zeta potential and encapsulation efficiency, while its pharmacokinetics and anti-tumor effects were also evaluated. Z-SMEDDS had stable physicochemical properties, including average particle size of 17.29 ± 0.07 nm, the zeta potential of -22.81 ± 0.29 mV, and the encapsulation efficiency of 97.96% ± 0.02%. In vitro release studies have shown the release of zingerone released by Z-SMEDDS was significantly higher than free zingerone in different release media. The relative oral bioavailability of Z-SMEDDS was 7.63 times compared with free drug. Meanwhile, the half inhibitory concentration （IC50）of Z-SMEDDS and free zingerone was 8.45 μg/mL and 13.30 μg/mL, respectively on HepG2. This study may provide a preliminary basis for further clinical research and application of Z-SMEDDS.     

Toll-like receptor 2 deficiency leads to delayed exacerbation of ischemic injury

ABSTRACT: BACKGROUND: : Using live imaging approach we have previously shown that microglia activation after stroke is characterized by marked and long-term induction of the Toll like Receptor 2 (TLR2) biophotonic signals. However, the role of TLR2 (and potentially other TLRs), beyond the acute innate immune response and an early neuroprotection against ischemic injury is not well understood. METHOD: S: The TLR2 -/- mice were subjected to transient middle cerebral artery occlusion (MCAO) followed by different reperfusion times. Analyses assessing microglial activation profile/innate immune response were performed using in situ hybridization, immunohistochemistry analysis, flow cytometry and inflammatory cytokine array. The effects of the TLR2 deficiency on the evolution of ischemic brain injury were analyzed using a cresyl violet staining of brain sections with appropriate lesion size estimation. RESULTS: : Here we report that TLR2 deficiency markedly affects post-stroke immune response resulting in delayed exacerbation of the ischemic injury. The temporal analysis of the microglia/macrophage activation profiles in TLR2 -/- mice and age-matched controls revealed reduced microglia/macrophage activation after stroke, reduced capacity of resident microglia to proliferate as well as decreased levels of MCP-1 and consequently lower levels of CD45high/CD11b+ expressing cells as shown by flow cytometry analysis. Importantly, although acute ischemic lesions (24-72hrs) were smaller in TLR2 -/- mice, the observed alterations in innate immune response were more pronounces at later time-points (at day 7) after initial stroke, which finally resulted in delayed exacerbation of ischemic lesion leading to larger chronic infarctions as compared to WT mice. Moreover, our results revealed that TLR2 deficiency is associated with significant decrease in the levels of neurotrophic/antiapoptotic factor IGF-1, expressed by microglia in the areas in- and around ischemic lesion. CONCLUSION: Altogether our results clearly suggest that optimal and timely microglial activation/innate immune response is needed to limit neuronal damage after stroke.     

Structural basis for p50RhoGAP BCH domain–mediated regulation of Rho inactivation

Spatiotemporal regulation of signaling cascades is crucial for various biological pathways, under the control of a range of scaffolding proteins. The BNIP-2 and Cdc42GAP Homology (BCH) domain is a highly conserved module that targets small GTPases and their regulators. Proteins bearing BCH domains are key for driving cell elongation, retraction, membrane protrusion, and other aspects of active morphogenesis during cell migration, myoblast differentiation, and neuritogenesis. We previously showed that the BCH domain of p50RhoGAP (ARHGAP1) sequesters RhoA from inactivation by its adjacent GAP domain; however, the underlying molecular mechanism for RhoA inactivation by p50RhoGAP remains unknown. Here, we report the crystal structure of the BCH domain of p50RhoGAP Schizosaccharomyces pombe and model the human p50RhoGAP BCH domain to understand its regulatory function using in vitro and cell line studies. We show that the BCH domain adopts an intertwined dimeric structure with asymmetric monomers and harbors a unique RhoA-binding loop and a lipid-binding pocket that anchors prenylated RhoA. Interestingly, the β5-strand of the BCH domain is involved in an intermolecular β-sheet, which is crucial for inhibition of the adjacent GAP domain. A destabilizing mutation in the β5-strand triggers the release of the GAP domain from autoinhibition. This renders p50RhoGAP active, thereby leading to RhoA inactivation and increased self-association of p50RhoGAP molecules via their BCH domains. Our results offer key insight into the concerted spatiotemporal regulation of Rho activity by BCH domain–containing proteins.

Small GTPases are molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state and are primarily involved in cytoskeletal reorganization during cell motility, morphogenesis, and cytokinesis (1, 2). These small GTPases are tightly controlled by activators and inactivators, such as guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs), respectively (3, 4), which are multidomain proteins that are themselves regulated through their interactions with other proteins, lipids, secondary messengers, and/or by posttranslational modifications (5–7). Despite our understanding of the mechanisms of action of GTPases, GAPs, and GEFs, little is known about how they are further regulated by other cellular proteins in tightly controlled local environments.The BNIP-2 and Cdc42GAP Homology (BCH) domain has emerged as a highly conserved and versatile scaffold protein domain that targets small GTPases, their GEFs, and GAPs to carry out various cellular processes in a spatial, temporal, and kinetic manner (8–15). BCH domain–containing proteins are classified into a distinct functional subclass of the CRAL_TRIO/Sec14 superfamily, with ∼175 BCH domain–containing proteins (in which 14 of them are in human) present across a range of eukaryotic species (16). Some well-studied BCH domain–containing proteins include BNIP-2, BNIP-H (CAYTAXIN), BNIP-XL, BNIP-Sα, p50RhoGAP (ARHGAP1), and BPGAP1 (ARHGAP8), with evidence to show their involvement in cell elongation, retraction, membrane protrusion, and other aspects of active morphogenesis during cell migration, growth activation and suppression, myoblast differentiation, and neuritogenesis (17–21). Aside from interacting with small GTPases and their regulators, some of these proteins can also associate with other signaling proteins, such as fibroblast growth factor receptor tyrosine kinases, myogenic Cdo receptor, p38-MAP kinase, Mek2/MP1, and metabolic enzymes, such as glutaminase and ATP-citrate lyase (17–26). Despite the functional diversity and versatility of BCH domain–containing proteins, the structure of the BCH domain and its various modes of interaction remain unknown. The BCH domain resembles the Sec14 domain (from the CRAL-TRIO family) (16, 27, 28), a domain with lipid-binding characteristics, which may suggest that the BCH domain could have a similar binding strategy. However, to date, the binding and the role of lipids in BCH domain function remain inconclusive.Of the BCH domain–containing proteins, we have focused on the structure and function of p50RhoGAP. p50RhoGAP comprises an N-terminal BCH domain and a C-terminal GAP domain separated by a proline-rich region. We found that p50RhoGAP contains a noncanonical RhoA-binding motif in its BCH domain and is associated with GAP-mediated cell rounding (13). Further, we showed previously that deletion of the BCH domain dramatically enhanced the activity of the adjacent GAP domain (13); however, the full dynamics of this interaction is unclear. Previously, it has been reported that the BCH and other domains regulate GAP activity in an autoinhibited manner (18, 21, 29, 30) involving the interactions of both the BCH and GAP domains, albeit the mechanism remains to be investigated. It has also been shown that a lipid moiety on Rac1 (a Rho GTPase) is necessary for its inactivation by p50RhoGAP (29, 31), which may imply a role in lipid binding. An understanding of how the BCH domain coordinates with the GAP domain to affect the local activity of RhoA and other GTPases would offer a previously unknown insight into the multifaceted regulation of Rho GTPase inactivation.To understand the BCH domain–mediated regulation of p50RhoGAP and RhoA activities, we have determined the crystal structure of a homologous p50RhoGAP BCH domain from S. pombe for functional interrogation. We show that the BCH domain adopts an intertwined dimeric structure with asymmetric monomers and harbors a unique RhoA-interacting loop and a lipid-binding pocket. Our results show that the lipid-binding region of the BCH domain helps to anchor the prenylation tail of RhoA while the loop interacts directly with RhoA. Moreover, we show that a mutation in the β5-strand releases the autoinhibition of the GAP domain by the BCH domain. This renders the GAP domain active, leading to RhoA inactivation and the associated phenotypic effects in yeast and HeLa cells. The released BCH domain also contributes to enhanced p50RhoGAP–p50RhoGAP interaction. Our findings offer crucial insights into the regulation of Rho signaling by BCH domain–containing proteins.