Dynamic layer rearrangement during growth of layered oxide films by molecular beam epitaxy

The A(n+1)B(n)O(3n+1) Ruddlesden-Popper homologous series offers a wide variety of functionalities including dielectric, ferroelectric, magnetic and catalytic properties. Unfortunately, the synthesis of such layered oxides has been a major challenge owing to the occurrence of growth defects that result in poor materials behaviour in the higher-order members. To understand the fundamental physics of layered oxide growth, we have developed an oxide molecular beam epitaxy system with in situ synchrotron X-ray scattering capability. We present results demonstrating that layered oxide films can dynamically rearrange during growth, leading to structures that are highly unexpected on the basis of the intended layer sequencing. Theoretical calculations indicate that rearrangement can occur in many layered oxide systems and suggest a general approach that may be essential for the construction of metastable Ruddlesden-Popper phases. We demonstrate the utility of the new-found growth strategy by performing the first atomically controlled synthesis of single-crystalline La3Ni2O7.

Repression of Farnesoid X receptor contributes to biliary injuries of liver grafts through disturbing cholangiocyte bile acid transport

Biliary epithelial damage is the critical point in the development of nonanastomotic strictures, a serious biliary complication after liver transplantation (LT). Current study focuses on the roles and mechanisms of unbalanced bile acid (BA) transporting of cholangiocytes in biliary epithelial damages following LT. Using rat LT models, we observed that biliary transit time (BTT) of BA was prolonged, and the degree and duration of BTT prolongation were related to the cold ischemia time of donor liver. Moreover, prolonged BTT was correlated with bile duct injury severity. The expression of Farnesoid X receptor (FXR) underwent a dramatic decrease after transplantation, and the decrease in FXR was related to cold ischemic time of donor liver. Negative correlation was observed between FXR expression and BTT. With in vitro cultured human biliary epithelial cells, it was observed that FXR expressions and DNA binding activities were repressed under hypoxic conditions. FXR repression by hypoxia mediated unparallel expressions of BA transporters and intracellular accumulation of BAs, which induced higher cell apoptosis rates and enhanced profibrotic factor expression in cholangiocytes. These findings indicated that FXR repression under ischemic/hypoxic conditions contributed to biliary epithelial damages by disturbing BA transporting of cholangiocytes after LT.

Galectin-7 in cardiac allografts in mice: increased expression compared with isografts and localization in infiltrating lymphocytes and vascular endothelial cells

We sought to identify elevated expression of galectin-7, a T-cell-binding protein, in renal allograft recipients undergoing acute rejection episodes. Allografts and isografts were examined immunohistologically and using quantitative Western blot analysis for galectin-7 protein. The expression of galectin-7 in T lymphocytes from draining lymph nodes in the recipient mice was examined using flow cytometry. We observed galectin-7 to gradually increase with time in the allografts to be significantly higher than that in isografts at days 3, 5, and 7 postoperative: 0.85 ± 0.03 versus 0.69 ± 0.05; 1.15 ± 0.11 versus 0.81 ± 0.02; and 2.02 ± 0.12 versus 0.81 ± 0.05 (P < .05). The majority of galectin-7 was located in the infiltrating lymphocytes and vascular endothelial cells. Furthermore, the percentage of CD4+galectin-7+ and CD8+galectin-7+ T cells from draining lymph nodes in the allograft group was higher than that in the isograft group: 28.0 ± 1.0% versus 1.2 ± 0.2%; and 12.4 ± 0.8% versus 0.4 ± 0.1% (P < .01). In conclusion, galectin-7 relates to acute allograft rejection and T-cell responses possibly as an accelerant.

A synthetic oxygen carrier in fibrin matrices promotes sciatic nerve regeneration in rats

Tissue-engineering nerve conduits have been studied for a long time in bridging large nerve defects. However, the low oxygen availability within the nerve conduits, which results in death of migratory Schwann cells (SC) or loss of the newly formed tissue's function, is still an obstacle for axonal regeneration. Thus, it was hypothesized that an oxygen-enriched conduit would enhance axonal regeneration and functional recovery in vivo. To address this issue, perfluorotributylamine (PFTBA) enriched fibrin hydrogel was prepared and injected into collagen-chitosan conduits. The conduit containing PFTBA-enriched fibrin hydrogel was then used to bridge a 12-mm sciatic nerve defect in rats. The control rats were bridged with collagen-chitosan conduits filled with fibrin matrices without PFTBA. It was found that axonal regeneration and functional recovery in the combined PFTBA group were significantly higher than those in the control group without PFTBA. Further investigations showed that the mRNA and protein levels of S-100, brain-derived neurotrophic factor and nerve growth factor were enhanced by PFTBA at 1 and 3weeks after surgery. However, the mRNA and protein levels of vascular endothelial growth factor were in a similar range between the combined PFTBA group and the control group without PFTBA. In addition, immunohistochemical results showed that the morphological appearances of regenerated nerve and survival of SC were enhanced by PFTBA at 4 and 12weeks after surgery. In conclusion, PFTBA-enriched nerve conduit is capable of enhancing axonal regeneration, which provides a new avenue for achieving better functional recovery in the treatment of nerve defect.

Influence of predispositions on post-traumatic stress disorder: does it vary by trauma severity?

BACKGROUND

Only a minority of trauma victims (<10%) develops post-traumatic stress disorder (PTSD), suggesting that victims vary in predispositions to the PTSD response to traumas. It is assumed that the influence of predispositions is inversely related to trauma severity: when trauma is extreme predispositions are assumed to play a secondary role. This assumption has not been tested. We estimate the influence of key predispositions on PTSD induced by an extreme trauma - associated with a high percentage of PTSD - (sexual assault), relative to events of lower magnitude (accidents, disaster, and unexpected death of someone close).

METHOD

The National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) is representative of the adult population of the USA. A total of 34 653 respondents completed the second wave in which lifetime PTSD was assessed. We conducted three series of multinomial logistic regressions, comparing the influence of six predispositions on the PTSD effect of sexual assault with each comparison event. Three pre-existing disorders and three parental history variables were examined.

RESULTS

Predispositions predicted elevated PTSD risk among victims of sexual assault as they did among victims of comparison events. We detected no evidence that the influence of predispositions on PTSD risk was significantly lower when the event was sexual assault, relative to accidents, disasters and unexpected death of someone close.

CONCLUSIONS

Important predispositions increase the risk of PTSD following sexual assault as much as they do following accidents, disaster, and unexpected death of someone close. Research on other predispositions and alternative classifications of event severity would be illuminating.

Effects of waterborne acephate exposure on antioxidant responses and acetylcholinesterase activities in Synechogobius hasta

The present study was conducted to determine the 24, 48, 72, and 96-h median lethal concentration (LC50) of acephate and investigate the antioxidant response and acetylcholinesterase (AChE) activities in liver, gill, and spleen of Synechogobius hasta exposed to 0 (control), 5, and 10 mg/L acephate, at the fixed interval time of 24, 48, 72, and 96 h, respectively. LC50 value was 60.83 mg/L at 24 h, 51.36 mg/L at 48 h, 47.07 mg/L at 72 h and 40.13 mg/L at 96 h, respectively. Dismutase (SOD), catalase (CAT), AChE activities, and malondialdehyde (MDA) levels in these tissues for the control remained stable over the exposure period. However, for the two tested groups, tissue-, dose-, and time-dependent responses of these parameters were observed in S. hasta. In general, hepatic SOD and CAT activities were significantly inhibited at 24 h, activated, and increased at 48 h, but again inhibited from 48 to 96 h in fish exposed to the two tested concentrations. Hepatic MDA levels of fish for the two tested concentration peaked at 48 h, significantly higher than the control. Hepatic AChE activity was inhibited at 24 h, peaked at 48 h, and then declined at 72 h for the two tested groups. For gills, the highest SOD and CAT activities for the two tested groups were observed at 48 h, higher than the control. AChE activities for the two tested groups were significantly inhibited at 24 h, but activated at 48 h. At 96 h, AChE activities among the treatments showed no significant differences. Gill MDA levels at 48 h for the tested groups were significantly higher than the control, but showed no significant differences at 24 and 72 h among the treatments. In spleen, SOD and CAT activities at 48 h for the two tested groups were significantly higher than those in the control, but at 96 h the vice versa was true. Spleenic AChE activities and MDA levels for the two tested groups were inhibited at 24 h, activated at 48 h, and then were again inhibited at 72 h. Based on these observations earlier, the results obtained in our study will have important toxicological implications for waterborne acephate pollution and, meantime, provide the basis for the effective risk assessment of acephate in water environment and appropriate safety recommendations for fish.

Histological evaluation of bone biopsy results during PVP or PKP of vertebral compression fractures

Percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) is utilized for the treatment of vertebral compression fractures (VCFs). The present study was conducted to evaluate biopsy results obtained from VCFs during PVP or PKP. Between January 2003 and December 2011, 692 vertebral body biopsies were obtained from 546 patients (442 females and 104 males; mean age, 72.3 years), who underwent PVP or PKP for treatment of VCFs. A history of malignancy was identified in 44 patients. Histological/immunohistochemical evaluations were performed by experienced pathologists and 89.9% of biopsies obtained from 546 patients were suitable for histological/immunohistochemical evaluation. The biopsy results of 398 patients were in good agreement with the diagnosis of osteoporotic VCFs. Among the 44 patients with a history of malignancy, malignancy was identified in 25 patients, while osteoporosis was identified in 16 patients. Biopsies of the other 3 patients were not suitable for pathological examination. There were only 2 patients with previously undiagnosed malignancy. One patient was diagnosed with multiple myeloma, while another patient was diagnosed with metastatic carcinoma. In the present study, the rate of unsuspected malignancy was 0.4%. No symptomatic complications occurred as a result of biopsy. The results indicate that biopsy is safely performed during PVP or PKP and it is an efficacious procedure that verifies the pathological process and assists in identifying previously unsuspected processes responsible for VCFs. We recommend obtaining the biopsy of every collapsed vertebral body during PVP or PKP procedures.

Gonadotrophin-releasing hormone signalling downstream of calmodulin

Gonadotrophin-releasing hormone (GnRH) regulates reproduction via binding a G-protein coupled receptor on the surface of the gonadotroph, through which it transmits signals, mostly via the mitogen-activated protein (MAPK) cascade, to increase synthesis of the gonadotrophin hormones: luteinising hormone (LH) and follicle-stimulating hormone (FSH). Activation of the MAPK cascade requires an elevation in cytosolic Ca(2+) levels, which is a result of both calcium influx and mobilisation from intracellular stores. However, Ca(2+) also transmits signals via an MAPK-independent pathway, through binding calmodulin (CaM), which is then able to bind a number of proteins to impart diverse downstream effects. Although the ability of GnRH to activate CaM was recognised over 20 years ago, only recently have some of the downstream effects been elucidated. GnRH was shown to activate the CaM-dependent phosphatase, calcineurin, which targets gonadotrophin gene expression both directly and indirectly via transcription factors such as nuclear factor of activated T-cells and Nur77, the Transducer of Regulated CREB (TORC) co-activators and also the prolyl isomerase, Pin1. Gonadotrophin gene expression is also regulated by GnRH-induced CaM-dependent kinases (CaMKs); CaMKI is able to derepress the histone deacetylase-inhibition of β-subunit gene expression, whereas CaMKII appears to be essential for the GnRH-activation of all three subunit genes. Asides from activating gonadotrophin gene expression, GnRH also exerts additional effects on gonadotroph function, some of which clearly occur via CaM, including the proliferation of immature gonadotrophs, which is dependent on calcineurin. In this review, we summarise these pathways, and discuss the additional functions that have been proposed for CaM with respect to modifying GnRH-induced signalling pathways via the regulation of the small GTP-binding protein, Gem, and/or the regulator of G-protein signalling protein 2.

Hypertonic saline reduces lipopolysaccharide-induced mouse brain edema through inhibiting aquaporin 4 expression

INTRODUCTION

Three percent sodium chloride (NaCl) treatment has been shown to reduce brain edema and inhibited brain aquaporin 4 (AQP4) expression in bacterial meningitis induced by Escherichia coli. Lipopolysaccharide (LPS) is the main pathogenic component of E. coli. We aimed to explore the effect of 3% NaCl in mouse brain edema induced by LPS, as well as to elucidate the potential mechanisms of action.

METHODS

Three percent NaCl was used to treat cerebral edema induced by LPS in mice in vivo. Brain water content, IL-1β, TNFα, immunoglobulin G (IgG), AQP4 mRNA and protein were measured in brain tissues. IL-1β, 3% NaCl and calphostin C (a specific inhibitor of protein kinase C) were used to treat the primary astrocytes in vitro. AQP4 mRNA and protein were measured in astrocytes. Differences in various groups were determined by one-way analysis of variance.

RESULTS

Three percent NaCl attenuated the increase of brain water content, IL-1β, TNFα, IgG, AQP4 mRNA and protein in brain tissues induced by LPS. Three percent NaCl inhibited the increase of AQP4 mRNA and protein in astrocytes induced by IL-1β in vitro. Calphostin C blocked the decrease of AQP4 mRNA and protein in astrocytes induced by 3% NaCl in vitro.

CONCLUSIONS

Osmotherapy with 3% NaCl ameliorated LPS-induced cerebral edema in vivo. In addition to its osmotic force, 3% NaCl exerted anti-edema effects possibly through down-regulating the expression of proinflammatory cytokines (IL-1β and TNFα) and inhibiting the expression of AQP4 induced by proinflammatory cytokines. Three percent NaCl attenuated the expression of AQP4 through activation of protein kinase C in astrocytes.

One-way transmission of linearly polarized light in plasmonic subwavelength metallic grating cascaded with dielectric grating

We show that optical transmission of linearly polarized light through a plasmonic subwavelength metallic grating cascaded with a dielectric grating at a 45° angle to each other is asymmetric in opposite directions. A key characteristic of this asymmetric transmission is that the polarization of the transmitted light is changed. Simulation results reveal that transmission of 0.92 in one direction and 10(-5) in the opposite direction can be obtained at normal incidence at a wavelength of 1550 nm. Because of their high optical performance and loose fabrication requirements, the structures may provide practical applications in the control of light transmission.

Induction of autophagy and senescence by knockdown of ROC1 E3 ubiquitin ligase to suppress the growth of liver cancer cells

Regulator of Cullins-1 (ROC1) or RING box protein-1 (RBX1) is an essential RING component of Cullin-RING ligase (CRL). Our previous studies showed that ROC1 is required for the growth of several cancer cell lines while ROC1 siRNA silencing inactivates CRL, leading to cell cycle arrest, cell senescence and/or apoptosis. However, it is completely unknown whether ROC1 knockdown triggers autophagic response by inactivating CRL. Moreover, the role of ROC1 in liver cancer remains elusive. In this study, we reported that ROC1 knockdown significantly inhibited the growth of liver cancer cells by sequentially and independently inducing autophagy and p21-dependent cell senescence. Mechanism analysis revealed that ROC1 silencing triggered autophagy by inhibition of mammalian target of rapamycin (mTOR) activity due to accumulation of mTOR-inhibitory protein Deptor, a substrate of CRL. Consistently, Deptor knockdown significantly blocked autophagy response upon ROC1 silencing. Biologically, autophagy response upon ROC1 silencing was a survival signal, and blockage of autophagy pathway sensitized cancer cells to apoptosis. Finally, we demonstrated that ROC1 was overexpressed in hepatocellular carcinomas, which is associated with poor prognosis of liver cancer patients. These findings suggest that ROC1 is an appealing drug target for liver cancer and provide a proof-of-concept evidence for a novel drug combination of ROC1 inhibitor and an autophagy inhibitor for effective treatment of liver cancer by enhancing apoptosis.

Sandwich vertebral fracture in the study of adjacent-level fracture after vertebral cement augmentation

The literature is inconclusive on the development of adjacent-level vertebral fracture after initial cement augmentation. A preliminary hypotheses is that cement injection exaggerates force transmission to the adjacent vertebral bodies, thereby predisposing those levels to future fractures. A sandwich vertebra is an intact vertebral body located between 2 previously cemented vertebrae. The purpose of this study was to determine whether the risk of adjacent-level fracture increased due to load shift after a cement injection procedure. The authors retrospectively investigated the rate of adjacent-level fracture after sandwiching compared with conservative treatment and determined the potential causative factors of sandwich vertebral fracture. Age, sex, weight, height, body mass index, follow-up period, and location of sandwich level (T10-L2 or nonT10-L2 junction) were assessed. Surgical variables, including surgical procedure (vertebroplasty or balloon kyphoplasty), surgical approach (through uni- or bilateral pedicle), volume of cement injected into the painful vertebrae, cement leakage into the intervertebral disk, cumulative number of treated levels, and pre- and postoperative kyphotic angulation of the sandwich region, were also analyzed. Nine of 42 sandwiched levels developed fatigue fractures, whereas 11 of 71 patients treated with conservative therapy sustained new vertebral fractures adjacent to the treated levels. Only preoperative kyphotic angulation was the variable positively associated with sandwich vertebral fracture at follow-up (P=.021). Although subjected to double load shifts, the sandwich vertebra was not prone to structural failure. Thus, cement augmentation protocol does not increase the incidence of adjacent vertebral fracture.

Expansive open-door laminoplasty with titanium miniplate versus sutures

Expansive laminoplasty is an effective treatment for cervical myelopathy. Since the design of classic open-door laminoplasty with the use of suture, the procedure has been modified to reduce complications such as restenosis, axial symptoms, and segmental motor paralysis. Expansive open-door laminoplasty with the use of titanium miniplate is becoming popular. It is effective in expanding spinal canal dimensions with good clinical efficacy. However, a lack of studies exist comparing titanium miniplate fixation with classical suture fixation.We performed a retrospective study of 54 patients with cervical myelopathy. Twenty-nine patients (4 women and 25 men) receiving expansive open-door laminoplasty by titanium miniplate fixation were classified as the modified group, and 25 patients (5 women and 20 men) fixed with suture served as the control group. Clinical and radiologic outcomes were assessed. No significant differences were observed in Japanese Orthopaedic Association scores and the recovery rate of C5 palsy. The incidence of axial symptoms in the modified group was significantly lower than that in control group. Radiologic examination showed that postoperative C2-C7 lordosis and range of motion of the cervical spine in the modified group were preserved. No significant differences were observed in mean anteroposterior diameter and open angle in the 2 groups. Both surgical protocols were effective in preventing reclosure of open laminae. Furthermore, the modified laminoplasty was superior in reducing the incidence of axial symptoms and loss of cervical lordosis and range of motion.

Protective effects of calcium on copper toxicity in Pelteobagrus fulvidraco: copper accumulation, enzymatic activities, histology

The present study was conducted to determine interactive effects of waterborne co-exposure of copper (Cu) and calcium (Ca) on Cu accumulation, enzymatic activities and histology in yellow catfish Pelteobagrus fulvidraco and test the prediction that Ca could protect against Cu--induced toxicity in the fish species. Yellow catfish were exposed to 0, 1.0, 2.0 mg Cu/l, in combination with 0 and 50 mg Ca/l. Waterborne Cu and Ca co-exposure influenced the majority of tested enzymatic activities (succinate dehydrogenase, malic dehydrogenase, lactate dehydrogenase, lipoprotein lipase and hepatic lipase), and changed Cu contents in several organs (gill, liver, kidney, gastrointestine and muscle). For histological observations, at the same Ca level, waterborne Cu exposure induced injuries in gills and liver. However, Ca addition seemed to mitigate the severity of Cu--induced injuries. Thus, our study demonstrated that Ca had the capacity to reduce Cu toxicity in P. fulvidraco.