Improving Bond Strength of Translucent Zirconia Through Surface Treatment With SiO2-ZrO2 Coatings

BACKGROUND

Translucent monolithic zirconia ceramics have been applied in dental clinics due to their esthetic translucent formulations and mechanical properties. Considering inherent ceramic brittleness, adhesive bonding with resin composite increases the fracture resistance of ceramic restorations. However, zirconia is a chemically stable material that is difficult to adhesively bond with resin.

OBJECTIVES

To investigate the influences of SiO2-ZrO2 coatings on adhesive bonding of zirconia and the surface characterization of those coatings.

METHODS AND MATERIALS

Translucent zirconia discs were classified into groups based on surface treatments: CT (control), SB (sandblasting), C21(SiO2:ZrO2=2:1), C11(SiO2:ZrO2=1:1), and C12 (SiO2:ZrO2=1:2) (n=10). Surface characterization of coatings on zirconia were analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness assessment (Ra), X-ray diffraction (XRD), water contact angle (WCA), translucency parameter (TP), and shear bond strength (SBS). Two-way ANOVA for shear bond strength results and ANOVA for Ra and WCA were performed.

RESULTS

SEM images revealed SiO2 islands on zirconia disks coated with SiO2-ZrO2. Surface roughness of C12, C11, and C21 groups was significantly larger than those of groups SB and CT (p<0.05). XRD results showed that phase transformation of zirconia disks was detected only in the SB group. In addition, SiO2-ZrO2 coatings reduced WCA. The translucency decreased only in group C21. Group C11 showed the highest shear bond strength under both aging conditions.

CONCLUSION

SiO2-ZrO2 coating is a promising method to enhance the adhesive resin bonding of translucent zirconia without causing phase transformation of translucent zirconia.

Learning Intention-Aware Policies in Deep Reinforcement Learning

Deep reinforcement learning (DRL) provides an agent with an optimal policy so as to maximize the cumulative rewards. The policy defined in DRL mainly depends on the state, historical memory, and policy model parameters. However, we humans usually take actions according to our own intentions, such as moving fast or slow, besides the elements included in the traditional policy models. In order to make the action-choosing mechanism more similar to humans and make the agent to select actions that incorporate intentions, we propose an intention-aware policy learning method in this letter To formalize this process, we first define an intention-aware policy by incorporating the intention information into the policy model, which is learned by maximizing the cumulative rewards with the mutual information (MI) between the intention and the action. Then we derive an approximation of the MI objective that can be optimized efficiently. Finally, we demonstrate the effectiveness of the intention-aware policy in the classical MuJoCo control task and the multigoal continuous chain walking task.

A Hierarchical Bayesian Latent Class Model for the Diagnostic Performance of Mini-Mental State Examination and Montreal Cognitive Assessment in Screening Mild Cognitive Impairment Due to Alzheimer's Disease

BACKGROUND

The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) are low costing and noninvasive neuropsychological tests in screening Mild Cognitive Impairment (MCI) due to Alzheimer's disease (AD). There is no consensus on which test performs better in detecting MCI due to AD based on the different imperfect reference standards. Therefore, we conducted a meta-analysis to assess the diagnostic performance of MMSE and MoCA for screening MCI due to AD in the absence of a gold standard.

METHODS

Six electronic databases were searched for relevant studies until April, 2022. A hierarchical Bayesian latent class model was used to estimate the pooled sensitivity and specificity of MoCA and MMSE in the absence of a gold standard.

RESULTS

90 eligible studies covering 21273 individuals for MMSE, 26631 individuals for MoCA were included in this meta-analysis. The pooled sensitivity was 0.71(95%CI: 0.67-0.74) for MMSE and 0.85(95%CI: 0.83-0.88) for MoCA, while the pooled specificity was 0.71(95%CI: 0.68-0.74) for MMSE and 0.79(95%CI: 0.76-0.81) for MoCA. MoCA was useful to "rule in" and "rule out" the diagnosis of MCI due to AD with higher positive likelihood ratio (4.07; 95%CI: 3.60-4.62) and lower negative likelihood ratio (0.18; 95%CI: 0.16-0.22). Moreover, the diagnostic odds ratio of MoCA was 22.08(95%CI: 17.24-28.29), which showed significantly favorable diagnostic performance.

CONCLUSIONS

It suggests that MoCA has greater diagnostic performance than MMSE for differentiating MCI due to AD when the gold standard is absent. However, these results should be taken with caution given the heterogeneity observed.

Characterizing the air pollution of the cities in the closure of corona virus disease 2019 in China

With the rapid development of industrialization and urbanization in China, energy and vehicle consumption have continued to increase in recent years and air pollution has become serious. In early 2020, Corona Virus Disease 2019 broke out in Wuhan, China. From January 29, 2020, several sources of the air pollution almost all stopped working, including gasoline burning vehicles, dust producing building sites, coal-fired factories, etc. Five indicators of the atmospheric environmental quality were observed from December 19, 2019 to April 30, 2020 in nine cities and 1-h average concentrations, 24-h average concentrations and Air Quality Index were assessed. The 1-h average concentrations of the nitrogen dioxide, the ozone and the sulfur dioxide showed obvious difference though the closure did not change the sequence of the five pollutants' concentrations in the air at diverse sampling moments. The changing of the 24-h average concentrations of the five pollutants indicated the amount of pollutants in the air were greatly affected by human activities. The nitrogen dioxide, the sulfur dioxide and the particulate matters decreased obviously in the closure. The air in the metropolis and the south-east cities were relatively clean and the pollutants' concentrations decreased slightly during the closure period. The northern and the heavy industrial cities showed significant drop on air pollution indicators and the air quality of the two city groups could be greatly improved if some effective measures could be taken of environmental management and regional development.

Block Diagonal Hybrid Precoding and Power Allocation for QoS-Aware BDMA Downlink Transmissions

Beam Division Multiple Access (BDMA) with hybrid precoding has recently been proposed for multi-user multiple-input multiple-output (MU-MIMO) systems by simultaneously transmitting multiple digitally precoded users' data-streams via different beams. In contrast to most existing works that assume the number of radio frequency (RF) chains must be greater than or equal to that of data-streams, this work proposes a novel BDMA downlink system by first grouping transmitting data-streams before digitally precoding data group by group. To fully harvest the benefits of this new architecture, a greedy user grouping algorithm is devised to minimize the inter-group interference while two digital precoding approaches are developed to suppress the intra-group interference by maximizing the signal-to-interference-and-noise ratio (SINR) and the signal-to-leakage-and-noise ratio (SLNR), respectively. As a result, the proposed BDMA system requires less RF chains than the total number of transmit data-streams. Furthermore, we optimize the power allocation to satisfy each user's quality of service (QoS) requirement using the D.C. (difference of convex functions) programming technique. Simulation results confirm the effectiveness of the proposed scheme.

Graphene enhanced field emission from InP nanocrystals

We report the observation of field emission (FE) from InP nanocrystals (NCs) epitaxially grown on an array of p-Si nanotips. We prove that FE can be enhanced by covering the InP NCs with graphene. The measurements are performed inside a scanning electron microscope chamber with a nano-controlled W-thread used as an anode. We analyze the FE by Fowler-Nordheim theory and find that the field enhancement factor increases monotonically with the spacing between the anode and the cathode. We also show that InP/p-Si junction has a rectifying behavior, while graphene on InP creates an ohmic contact. Understanding the fundamentals of such nanojunctions is key for applications in nanoelectronics.

Electron holography on HfO2/HfO2-x bilayer structures with multilevel resistive switching properties

Unveiling the physical nature of the oxygen-deficient conductive filaments (CFs) that are responsible for the resistive switching of the HfO₂-based resistive random access memory (RRAM) devices represents a challenging task due to the oxygen vacancy related defect nature and nanometer size of the CFs. As a first important step to this goal, we demonstrate in this work direct visualization and a study of physico-chemical properties of oxygen-deficient amorphous HfO_2-x by carrying out transmission electron microscopy electron holography as well as energy dispersive x-ray spectroscopy on HfO₂/HfO_2-x bilayer heterostructures, which are realized by reactive molecular beam epitaxy. Furthermore, compared to single layer devices, Pt/HfO₂/HfO_2-x /TiN bilayer devices show enhanced resistive switching characteristics with multilevel behavior, indicating their potential as electronic synapses in future neuromorphic computing applications.

Puerarin prevents inflammation and apoptosis in the neurocytes of a murine Parkinson's disease model

The aim of this study was to investigate Parkinson's disease (PD) using a murine model of PD. Specifically, we aimed to explore the mechanism by which puerarin prevents inflammation and apoptosis in neurocytes. Eighty healthy male C57/BL6 mice were randomly selected and divided into four groups (N = 20 each): control group; PD group; PD+puerarin group; and puerarin group. At the end of the treatment period, the animals' brains were removed after perfusion and decollation. The protein expression levels of tyrosine hydroxylase (TH) in the murine brains were assessed by immunohistochemistry and the protein expression levels of TH, glial fibrillary acidic protein (GFAP), inducible nitric oxide synthase (iNOS), cleaved Caspase-3, and Bax in the substantia nigra and corpus striatum of the animals were assessed by western blotting. The spontaneous activity of the PD mice was found to be significantly higher after puerarin treatment and the distance traveled by mice in an open field assessment was 1700 cm further in puerarin-treated PD mice than in PD mice. Immunohistochemistry and western blotting analyses indicated that the expression of TH was significantly higher (2.63-fold) in puerarin-treated PD mice than in untreated PD mice and that the expression of GFAP in PD mice was significantly reduced (~45%) by puerarin treatment. These findings lead us to conclude that puerarin significantly alleviates 1-methyl-4-phenyl- 1,2,3,6-tetrahydropyridine-induced injury in dopaminergic neurons. Puerarin mediates anti-apoptotic and anti-inflammatory activities and plays a neuroprotective role.

Vitamin D prevents articular cartilage erosion by regulating collagen II turnover through TGF-β1 in ovariectomized rats

OBJECTIVE

To explore the effect of vitamin D on turnover of articular cartilage with ovariectomy (OVX) induced OA, and to investigate transforming growth factor-β1 (TGF-β1) as a possible underlying mechanism mediated by 1α,25(OH)2D3.

DESIGN

Sixty-six rats were randomly allocated into seven groups: sham plus control diet (SHAM+CTL), OVX+CTL diet, sham plus vitamin D-deficient (VDD) diet, OVX+VDD diet, and three groups of ovariectomized rats treated with different doses of 1α,25(OH)2D3. The cartilage erosion and the levels of serum 17β-estradiol, 1α,25(OH)2D3 and C-telopeptide of type II collagen (CTX-II) were measured. TGF-β1, type II Collagen (CII), matrix metalloproteinases (MMP)-9,-13 in articular cartilage were assessed by immunohistochemistry. TGF-β1 and CTX-II expression were measured in articular cartilage chondrocytes treated with/without tumor necrosis factor (TNF-α), 1α,25(OH)2D3, and TGF-β receptor inhibitor (SB505124) in vitro.

RESULTS

Cartilage erosion due to OVX was significantly reduced in a dose-dependent manner by 1α,25(OH)2D3 supplementation, and exacerbated by VDD. The expressions of TGF-β1 and CII in articular cartilage were suppressed by OVX and VDD, and rescued by 1α,25(OH)2D3 supplementation. The expression of MMP-9,-13 in articular cartilage increased with OVX and VDD, and decreased with 1α,25(OH)2D3 supplementation. In vitro experiments showed that 1α,25(OH)2D3 increased the TGF-β1 expression of TNF-α stimulated chondrocytes in a dose-dependent manner. 1α,25(OH)2D3 significantly counteracted the increased CTX-II release due to TNF-α stimulation, and this effect was significantly suppressed by SB505124.

CONCLUSION

VDD aggravated cartilage erosion, and 1α,25(OH)2D3 supplementation showed protective effects in OVX-induced OA partly through the TGF-β1 pathway.

Post deposition annealing of epitaxial Ce1−xPrxO2−δfilms grown on Si(111)

In this work the structural and morphological changes of Ce_1−xPr_xO_2−δ(x= 0.20, 0.35 and 0.75) films grown on Si(111) due to post deposition annealing are investigated by low energy electron diffraction combined with a spot profile analysis.

Structural transitions of epitaxial ceria films on Si(111)

The structural changes of a (111) oriented CeO2 film grown on a Si(111) substrate covered with a hex-Pr2O3(0001) interface layer due to post deposition annealing are investigated. X-ray photoelectron spectroscopy measurements revealing the near surface stoichiometry show that the film reduces continuously upon extended heat treatment. The film is not homogeneously reduced since several coexisting crystalline ceria phases are stabilized due to subsequent annealing at different temperatures as revealed by high resolution low energy electron diffraction and X-ray diffraction. The electron diffraction measurements show that after annealing at 660 °C the ι-phase (Ce7O12) is formed at the surface which exhibits a (√7 × √7)R19.1° structure. Furthermore, a (√27 × √27)R30° surface structure with a stoichiometry close to Ce2O3 is stabilized after annealing at 860 °C which cannot be attributed to any bulk phase of ceria stable at room temperature. In addition, it is shown that the fully reduced ceria (Ce2O3) film exhibits a bixbyite structure. Polycrystalline silicate (CeSi(x)O(y)) and crystalline silicide (CeSi1.67) are formed at 850 °C and detected at the surface after annealing above 900 °C.

Insulator-metal transition of VO₂ ultrathin films on silicon: evidence for an electronic origin by infrared spectroscopy

We report on the first simultaneous observations of both electronic and structural temperature-induced insulator-to-metal transition (IMT) in VO2 ultrathin films, made possible by the use of broad range transmission infrared spectroscopy. Thanks to these techniques, the infrared phonon structures, as well as the appearance of the free carrier signature, were resolved for the first time. The temperature-resolved spectra allowed the determination of the temperature hysteresis for both the structural (monoclinic-to-rutile) and electronic (insulator-to-metallic) transitions. The combination of these new observations and DFT simulations for the monoclinic structure allows us to verify the direct transition from monoclinic (M1) to rutile and exclude an intermediate structural monoclinic form (M2). The delay in structural modification compared to the primer electronic transition (325 K compared to 304 K) supports the role of free charges as the transition driving force. The shape of the free charge hysteresis suggests that the primer electronic transition occurs first at 304 K, followed by both its propagation to the heart of the layer and the structural transition when T increases. This study outlines further the potential of VO2 ultrathin films integrated on silicon for optoelectronics and microelectronics.

Meta-analysis of temporary ileostomy versus colostomy for colorectal anastomoses

BACKGROUND/AIMS

Defunctioning stoma is a common surgical procedure, it is now generally acknowledged that defunctioning stoma significantly reduce the rates of complications in colorectal surgery, but the choice of temporary ileostomy or temporary colostomy for defunctioning colorectal anastomoses remains controversial. This meta-analysis evaluated two types of defunctioning stoma to determine whether one is superior to the other.

METHODOLOGY

Studies and relevant literatures comparing temporary ileostomy with temporary colostomy for defunctioning colorectal anastomoses were searched though PubMed, Embase and The Cochrane Library. The rates of complications were pooled and compared using a meta-analysis. The risk ratios were calculated with 95% confidence intervals to evaluate the safety and efficacy of each technique.

RESULTS

Five randomized controlled trials and seven non-randomized studies were included, with 1687 patients in total. The meta-analysis of the RCTs demonstrated a lower risk of stoma prolapse (RR 0.15; 95% CI: 0.04-0.48, p = 0.001) in the temporary ileostomy group. Meta-analysis of the non-randomized studies showed a lower risk of stoma prolapse (RR 0.26; 95% CI 0.10-0.67, p = 0.005) and wound infection after stoma closure (RR 0.28; 95% CI 0.5-0.52, p < 0.0001) in the temporary ileostomy group. No other statistically significant difference was observed for complications.

CONCLUSIONS

Each type of defunctioning stoma has its advantages and disadvantages, and there is not a strong evidence for the superiority of one temporary stoma over another for colorectal anastomoses. According to this, large scale RCTs and high quality studies are needed to conduct.

WE-C-217BCD-04: Multimodality Imaging of Breast Cancer Experimental Lung Metastasis

PURPOSE

Metastatic breast cancer (MBC) is incurable. The clinical gold standard for assessing tumor microvessel density (MVD), an independent prognostic marker in MBC, is CD 105 staining. The goal of this study is to develop a positron emission tomography (PET)/near-infrared fluorescent (NIRF) probe for imaging of CD105 expression in MBC (i.e. non-invasive measurement of MVD), as well as other applications such as early detection of metastasis, intraoperative guidance, etc.

METHODS

TRC105, a chimeric anti-CD105 mAb, was dual-labeled with a NIRF dye and ⁸⁹ Zr to yield ^{8 9} Zr-Df-TRC105-800CW. Luciferase-transfected 4T1 murine breast cancer cells were injected intravenously into female BALB/c mice to establish a lung MBC model. Bio luminescence imaging (BLI) was carried out to non- invasively monitor the lung tumor burden. Comprehensive in vivo/ex vivo studies were performed to investigate ^{8 9} Zr-Df-TRC105-800CW in this MBC model. Cetuximab was used as an isotype-matched control.

RESULTS

Radiolabeled TRC105 has high tumor uptake in many tumor types in addition to MBC (e.g. pancreatic/prostate cancer and brain tumor), revealing broad clinical potential for TRC105-based agents. FACS analysis of HUVECs showed no difference in CD 105 binding between TRC105 and Df- TRC105-800CW. PET imaging revealed that 4T1 lung tumor uptake of ⁸⁹ Zr-Df-TRC105-800CW was 8.7±1.4,10.9±0.5, and 9.7±1.1 %ID/g at 4, 24, and 48 h post-injection (n = 4), with excellent tumor contrast. Bio distribution studies, blocking, control studies with ^{8 9} Zr-Df-cetuximab- 800CW, ex vivo BLI/PET/NIRF imaging, and histology all confirmed CD 105 specificity of the tracer. NIRF imaging-guided removal of 4T1 tumors with Df-TRC105-800CW in a subcutaneous model was also straightforward.

CONCLUSIONS

We report the first PET/NIRF imaging of CD105 expression in a MBC model. Broad clinical potential of TRC105- based agents was shown in many tumor types, which also enabled early detection of small metastases and provided intraoperative guidance for tumor removal.

MR imaging assessment of lumbar intervertebral disk degeneration and age-related changes: apparent diffusion coefficient versus T2 quantitation

BACKGROUND AND PURPOSE

T2 and ADC mappings are 2 quantitative MR imaging tools for assessing IVDD. This study aimed to compare these 2 measures in detecting IVDD and its age-related changes.

MATERIALS AND METHODS

Thirty-seven asymptomatic volunteers and 28 patients with back pain or sciatica were examined, and their lumbar disk T2 and ADC maps were quantified via sagittal imaging protocols at 1.5T. For all participants, the Pfirrmann system was used by 2 radiologists for grading disks. T2 and ADC values in the inner portion of disks were measured, and their variances in different grades were analyzed by 1-way ANOVA testing. The ability of T2 and ADC measures to differentiate IVDD grades was compared on the basis of their ROC curves. For asymptomatic subjects, the correlations between age and the 2 MR imaging measures were assessed by the Pearson correlation test.

RESULTS

Both T2 and ADC values were found to decrease with the increasing Pfirrmann grades except T2 in grade V. Significant T2 differences were seen among grades I-IV, but not between grades IV and V. There were no significant ADC differences among grades I-III. Moreover, the areas under the ROC curves differed significantly (0.95 and 0.67 for T2 and ADC, respectively). Linear regression analysis revealed that T2 yielded more significant correlation with age (r = -0.77) than ADC did (r = -0.37).

CONCLUSIONS

T2 quantitation provides a more sensitive and robust approach for detecting and characterizing the early stage of IVDD and age-related disk changes.

Examination of the hdrRM regulon yields insight into the competence system of Streptococcus mutans

Previous studies have identified the hdrRM operon as a novel regulatory system induced by conditions of high cell density. Little is known about the genes under the control of this system, but a variety of important phenotypes are associated with either hdrR overexpression or mutation of hdrM. To characterize the regulatory function of the HdrRM system in Streptococcus mutans we used a microarray approach to compare the transcriptional profiles of an hdrR overexpression strain with an hdrM mutant. Both strains exhibited almost identical profiles, which included all of the known late competence genes as well as a variety of competence-induced bacteriocins. Through a combination of real-time reverse transcription-polymerase chain reaction (PCR), reporter gene analysis and random amplification of complementary DNA ends PCR, we confirmed the role of comX as a central intermediate regulator of numerous genes in the hdrRM regulon. Through these studies, we also identified novel comX-regulated genes required for natural competence. Taken together, our results suggest that the primary function of the HdrRM system is to regulate the late competence genes together with various bacteriocins. This occurs independently of the ComCDE system, even though both systems regulate nearly identical genes. This suggests that S. mutans has multiple parallel input sensory systems that control the same output response: the induction of natural competence and concurrent production of bacteriocins.

BRSK2 expression as a prognosis marker in pancreatic cancer patients

e15603

Background: The prognosis of pancreatic cancer remains dismal because of difficult early diagnosis, low resection rate and aggressive biological behavior. The research of factors related to oncogenesis, tumor infiltration and metastasis is valuable. AMPK(AMP-activated protein kinase)family is a group of regulators on the cellular energy metabolism which are sensitive to the cytoplasmic change of AMP/ATP ratio. As a member of AMPK, BRSK2 is found to be expressed in human pancreatic cell line and facilitate the tumor cell survival on glucose starving. In order to examine the expression of BRSK2 in human pancreatic cancer and explore the underline clinical implication, human pancreatic tissue was examined immunohistochemically Correlation of tumor biological behavior, prognosis and BRSK2 expression was examined. Methods: Seventy nine resected tumor specimens were collected. Immunochemical staining method was used to examine the expression pattern of BRSK2 translated protein. Semi-quantitative analysis was employed to compare the expression intensity and content of BRSK2 in tumor issues, peri-tumorous tissue and normal pancreatic tissue. Possible relationship of tumors differentiation, TNM stage, presence or absence of vessel and neural infiltration were explored with BRSK2 expression. The correlation of BRSK2 expression profile and patients survival was explored. Results: BRSK2 was weakly expressed in normal pancreatic tissues and peri-tumor tissues, including the islet and minor ducts. BRSK2 was strongly expressed in pancreatic cancer tissues, the expression intensity was correlated with extent of lymphatic metastasis, distant metastasis, TNM staging and neural invasion. Tumors with lymphatic metastasis, distant metastasis, neural invasion and later TNM stages showed stronger expression of BRSK2. The expression of BRSK2 in pancreatic cancer was closely correlated to the prognosis of patients, those with higher expression pattern showed bad prognosis. Conclusions: BRSK2 is up-regulated in pancreatic cancer; the expression of BRSK2 is correlated with tumor biological behavior and patient's prognosis.

No significant financial relationships to disclose.

Unscheduled apoptosis during acute inflammatory lung injury

Apoptosis is a mode of cell death currently thought to occur in the absence of inflammation. In contrast, inflammation follows unscheduled events such as acute tissue injury which results in necrosis, not apoptosis. We examined the relevance of this paradigm in three distinct models of acute lung injury; hyperoxia, oleic acid, and bacterial pneumonia. In every case, it was found that apoptosis is actually a prominent component of the acute and inflammatory phase of injury. Moreover, using strains of mice that are differentially sensitive to hyperoxic lung injury we observed that the percent of apoptotic cells was well correlated with the severity of lung injury. These observations suggest that apoptosis may be one of the biological consequences during acute injury and the failure to remove these apoptotic cells may also contribute to the inflammatory response.

[The black diaphragm intraocular lens implantation]

OBJECTIVE

To evaluate the clinical effect of the black diaphragm intraocular lens (IOL) implantation.

METHODS

The black diaphragm IOL implantation performed on 23 cases (23 eyes) of traumatic aniridia (21 eyes) and congenital aniridia (2 eyes) was studied retrospectively.

RESULTS

Photophobia was reduced obviously and the naked visual acuity was improved in all 23 cases after the black diaphragm IOL implantation, VA > or = 0.1 in 16 cases (70%). The complications included vitreous hemorrhage (2 eyes) in the operation, and there were exudates on the surface of IOL (13 eyes), IOP elevation (3 eyes), macular hole (1 eye), recurrent retinal detachment (1 eye) and corneal decompensation (5 eyes) after the operation.

CONCLUSION

The black diaphragm IOL implantation provides an effective means of treating traumatic or congenital aniridia, but the indication should be strictly controlled.

Microwave-assisted extraction of tanshinones from Salvia miltiorrhiza bunge with analysis by high-performance liquid chromatography

A novel microwave-assisted extraction (MAE) method has been developed for the extraction and determination of tanshinones (tanshinone IIA, cryptotanshinone and tanshinone I) from the root of Salvia miltiorrhiza bunge with analysis by HPLC. Various experimental conditions were investigated to optimize the percentage extraction. Under appropriate MAE conditions, such as ethanol concentrations of 95% (v/v), MAE for 2 min, liquid/solid ratio of 10:1 (ml/g), the percentage extraction can reach high in a short time. The percentage extraction (tanshinone IIA: 0.29%; cryptotanshinone: 0.23%; tanshinone I: 0.11%) by MAE was the same or even higher than conventional extraction methods. MAE only needs 2 min, but extraction at room temperature, heat reflux extraction, ultrasonic extraction and Soxhlet extraction need 24 h, 45 min, 75 min and 90 min, respectively. MAE was also available in pilot plant form for larger scale extraction.

Microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide

In the present study, a new microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide technique has been developed. The results show that microwave irradiation can dehydrate penicillin G sulfoxide from a water content of 14-26 to below 0.5% in 40-60 min in N2 or air. After washing with ethyl acetate to remove impurities and residual water, the penicillin G sulfoxide can be used to synthesize cephalosporanic acid. The recovery of cephalosporanic acid was equal to and the purity of cephalosporanic acid was higher by 2% than that of the current dehydration technique. FTIR spectroscopy was used to study the process of microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide.

Constitutive activation of Stat3 by the Src and JAK tyrosine kinases participates in growth regulation of human breast carcinoma cells

Constitutive activation of signal transducer and activator of transcription (STAT) proteins has been detected in a wide variety of human primary tumor specimens and tumor cell lines including blood malignancies, head and neck cancer, and breast cancer. We have previously demonstrated a high frequency of Stat3 DNA-binding activity that is constitutively-induced by an unknown mechanism in human breast cancer cell lines possessing elevated EGF receptor (EGF-R) and c-Src kinase activities. Using tyrosine kinase selective inhibitors, we show here that Src and JAK family tyrosine kinases cooperate to mediate constitutive Stat3 activation in the absence of EGF stimulation in model human breast cancer cell lines. Inhibition of Src or JAKs results in dose-dependent suppression of Stat3 DNA-binding activity, which is accompanied by growth inhibition and induction of programmed cell death. In addition, transfection of a dominant-negative form of Stat3 leads to growth inhibition involving apoptosis of breast cancer cells. These results indicate that the biological effects of the Src and JAK tyrosine kinase inhibitors are at least partially mediated by blocking Stat3 signaling. While EGF-R kinase activity is not required for constitutive Stat3 activation in breast cancer cells, EGF stimulation further increases STAT DNA-binding activity, consistent with an important role for EGF-R in STAT signaling and malignant progression. Analysis of primary breast tumor specimens from patients with advanced disease revealed that the majority exhibit elevated STAT DNA-binding activity compared to adjacent non-tumor tissues. Our findings, taken together, suggest that tyrosine kinases transduce signals through Stat3 protein that contribute to the growth and survival of human breast cancer cells in culture and potentially in vivo.

Overexpression of a dominant-negative signal transducer and activator of transcription 3 variant in tumor cells leads to production of soluble factors that induce apoptosis and cell cycle arrest

Gene therapy of B16 tumors with a dominant-negative signal transducer and activator of transcription (Stat3) variant, designated Stat3beta, results in inhibition of tumor growth and tumor regression. Although only 10-15% of the tumor cells are transfected in vivo, the Stat3beta-induced antitumor effect is associated with massive apoptosis of B16 tumor cells, indicative of a potent bystander effect. Here, we provide evidence that blocking Stat3 signaling in B16 cells results in release of soluble factors that are capable of inducing apoptosis and cell cycle arrest of nontransfected B16 cells. RNase protection assays using multi-template probes specific for key physiological regulators of apoptosis reveal that overexpression of Stat3beta in B16 tumor cells induces the expression of the apoptotic effector, tumor necrosis factor-related apoptosis-inducing ligand. These in vitro results suggest that the observed in vivo bystander effect leading to tumor cell growth inhibition is mediated, at least in part, by soluble factors produced as a result of overexpression of Stat3beta in tumor cells.

Bing de ling, a Chinese herbal formula, stimulates multifaceted immunologic responses in mice

Bing de ling is a Chinese herbal formula most commonly used in complementary medical settings against viral disorders. We have found that bing de ling potentiates upregulation of immune activity when administered to mice in dosages proportional to those used clinically. These mice demonstrated significant elevation of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production in splenocytes and enhancement of macrophage, natural killer cell, and lymphokine-activated killer cell cytotoxicity. These data are consistent with bing de ling's clinically observed efficacy against viruses and identify the formula as a promising candidate for clinical trials against diverse diseases that may respond to increased immunologic activity.

Gene therapy with dominant-negative Stat3 suppresses growth of the murine melanoma B16 tumor in vivo

Whereas signal transducers and activators of transcription were originally discovered as mediators of normal cytokine signaling, constitutive activation of certain signal transducer and activator of transcription proteins, including Stat3, has been found in increasing numbers of human cancers. Recently, a causal role for Stat3 activation in oncogenesis has been demonstrated, suggesting that Stat3 represents a novel target for cancer therapy. We report here that in vitro expression of a Stat3 variant with dominant-negative properties, Stat3beta, induced cell death in murine B16 melanoma cells that harbored activated Stat3. By contrast, expression of Stat3beta had no effect on normal fibroblasts or the Stat3-negative murine tumor MethA, suggesting that only tumor cells with activated Stat3 have become dependent on this pathway for survival. Significantly, gene therapy by electroinjection of the Stat3beta expression vector into preexisting B16 tumors caused inhibition of tumor growth as well as tumor regression. This Stat3beta-induced antitumor effect is associated with apoptosis of the B16 tumor cells in vivo. These findings demonstrate for the first time that interfering with Stat3 signaling induces potent antitumor activity in vivo and thus identify Stat3 as a potential molecular target for therapy of human cancers harboring activated Stat3.

[The suppressing effect of TIMP-3 gene transfection on the invasion and metastasis of human lung carcinoma cells line]

OBJECTIVE

The purpose of this study is to determine if increasing levels of tissue inhibitor of metalloproteinase 3 (TIMP-3) expression could suppress the malignant phenotype of human cancer cells.

METHODS

The recombinant expression vector, which contains full length cDNA of human TIMP-3, was constructed and transfected into BE1 cell line by lipofectin technique. The invasive and spontaneous metastatic potential was examined.

RESULTS

TIMP-3 mRNA expression in TIMP-3 gene transfected BE1 cells was upregulated as detected by Northern blot. The invasion of TIMP-3 gene-transfected cells across matrigel-coated filters was significantly decreased when compared with controls. Following subcutaneous injection into nude mice, the TIMP-3 transfected cells suppressed primary tumor growth, as characterized by reduced tumor incidence (9/12 vs 6/6), longer latency and reduced metastatic potential to the lungs (1/12 vs 5/6) and lymph nodes (5/12 vs 6/6).

CONCLUSION

The results suggest that upregulation of TIMP-3 expression in BE1 cells resulted in suppression of the invasive potential of BE1 cells in vitro as well as tumorigenic and metastatic potential in nude mice.

[Effect of B16 cells transfected with IL-2 gene on mouse immunity]

IL-2 was introduced into mice B16 melanoma cell line by using retrovirus infection method. Both B16 and B16-IL-2 cells were treated with Mit C beforehand and were then inoculated intraperitoneally as vaccines in mice respectively. Hanks solution was used instead of the vaccine in the control group. The data showed that the tumor incidence rate was zero in the group receiving B16-IL-2 vaccine followed by B16 inoculation. However, incidence rate was 100% in both the B16 vaccine immunization group and in the control groups. Experiments also indicated that the proliferation of splenic lymphocytes induced by MLTR, the specific cytotoxicity of CTL against B16 cells, the activities of splenic NK, LAK, and the level of IL-2 secretion in mice immunized by B16-IL-2 were much higher than those in the mice immunized only with B16 cells as well as the controls. These data indicated that secretion of IL-2 in mice promoted specific and nonspecific anti-tumor immunity of mice. The theoretic basis was provided for IL-2-secreting tumor vaccine.

[Miniplate osteosynthesis for multiple mandibular fractures]

This retrospective study involved 34 patients with multiple mandibular fractures. Monocortical miniplates were used for fixation of fractures followed by a short term intermaxillary fixation. All the patients were evaluated radiographically and clinically. The results indicated that all fractures healed uneventfully. No malocclusion, delayed union, injury of the nerves or teeth due to the procedure were found. We concluded that monocortical miniplate osteosynthesis is effective and reliable for multiple mandibular fractures, and a short term intermaxillary fixation is helpful for the healing of fracture.

[The effect of IL2 gene transfection on the growth and metastatic characteristics of muous B16 melanoma cells]

In order to investigate the antitumor effect of IL2 gene transfected tumor vaccine, gene transfected tumor cells which secrete IL2 in a comparatively sustained manner must be obtained. Their growth and metastatic characteristics must be identified. This study used the retrovirus infection method to introduce human IL2 cDNA into mouse B16 melanoma cells. Southern blot analysis confirmed the establishment of IL2-integrated B16 cells (B16-IL2). Northern blot also showed the expression of IL2 gene in mRNA level. IL2 secretion of B16-IL2 was comparatively stable for a period of 6 months with the highest production rate of 53u/ml. No obvious influence was observed on the morphology and growth of the tumor cells in vitro after the transfection of IL2-cDNA. But, their oncogenicity in vivo was reduced and the tumor growth induced by B16-IL2 cells was inhibited. Lung metastasis rate and extent was also reduced. This study laid the foundation for the preparation of an IL2-secreting tumor vaccine.

Effects of tetramethylpyrazine phosphate and sodium ferulate alone or in combination on hemodynamics in anesthetized dog

Hemodynamic actions of intravenous (iv) administration of tetramethylpyrazine phosphate (TMPP) and sodium ferulate (SF) alone or in combination were studied in anesthetized dogs. When given alone, TMPP increased left ventricular systolic pressure (LVSP), peak positive first derivative of left ventricular pressure (+LVdp/dt), coronary blood flow (CBF) and heart rate (HR) while decreasing mean aortic pressure (mAoP). SF alone did not produce any significant hemodynamic changes. When the two were administered in combination, SF antagonized dose-dependently the hemodynamic actions of TMPP. Results of this study did not support the efficacy of combined treatment of Ligusticum wallichi and Angelica root, which contain TMPP and SF respectively.

[Experimental histopathological studies of renal lesions induced by high- or low-osmolality contrast media]

To elucidate the morphological basis of renal lesions due to intravenous administration of radiocontrast media, a comparative study was performed by injecting contrast media with different properties, such as high-osmolar ionic diatrizoate (60% Urografin), low-osmolar ionic ioxaglate (Hexabix 320) and low-osmolar non-ionic iopamidol (lopamiron 300), via the tail vein of male Wistar rats. Physiologic saline was injected in controls. Each contrast media was administered singly as a low dose (1 g I/kg), a moderate dose (3 g I/kg) or a high dose (9 g I/kg) to three separate groups of rats. In additional groups of rats, a high dose of each contrast media (9 mg I/kg) was administered repeatedly two or four times. The animals were sacrificed chronologically from 5 minutes to 30 days after the last administration and their renal tissues were examined by light and electron microscopy. The results indicated that the low osmolar contrast media is beneficial in decreasing general symptoms, but there are no definite differences between high and low osmolar contrast media in the data of blood and urine examination after administration. The iodinated contrast media with a low or moderate dose does not induce definite histopathological changes of the renal tissue, however, with a high dose it causes vacuolization of proximal tubular epithelia, although this change recovers within three days. The repeated administration of contrast media with a high dose induces severe damage of proximal tubular epithelia with prominent vacuolization, appearance of intracytoplasmic granular structure and occasional cell necroses. The vacuolization appears even in distal and collective tubules and glomerular epithelia. Recovery is retarded under this condition. There are no qualitative histological differences of renal lesions induced by the three different contrast media. In conclusion, either high or low osmolar contrast media induces almost the same histological alteration in renal tissues under the same experimental conditions. The more the quantitative increase in administered iodinated contrast media, the more prominent is the histological impairment of the kidney. The degree of renal lesion and its recovery might depend on the dose of iodine rather than the osmolality of the contrast media.