Ab initio study of the topological itinerant transport properties observed between excited edge states in a 2D compound with the Mn15B16Ni composition

We theoretically demonstrate how the competition between band inversion and spin-orbit coupling (SOC) results in the nontrivial topology of band evolution, using two-dimensional (2D) Mn16B16 as a matrix. This study utilizes the ab initio method with the generalized gradient approximation (GGA+U scheme) and Wannier functions to investigate the topological and transport properties of the Ni-doped structure. The Ni atom induces dynamical antilocalization, which appears due to the phase accumulation between time-reversed fermion loops. A key observation is that when band inversion dominates over SOC, "twin" Weyl cones appear in the band structure, in which the Weyl cones caused by the large Berry curvature coupling with the net magnetization lead to the significantly enhanced anomalous Hall conductivity (AHC). Interestingly, the nested small polaron and energy band inversion coexist with SOC. An analysis of the projected energy band shows that the doped Ni atom induces a strong spin wave for both spin up and spin down.

Phononic band gap in random spring networks

We investigate the relation between topological and vibrational properties of networked materials by analyzing, both numerically and analytically, the properties of a random spring network model. We establish a pseudodispersion relation, which allows us to predict the existence of distinct transitions from extended to localized vibrational modes in this class of materials. Consequently, we propose an alternative method to control phonon and elastic wave propagation in disordered networks. In particular, the phonon band gap of our spring network model can be enhanced by either increasing its average degree or decreasing its assortativity coefficient. Applications to phonon band engineering and vibrational energy harvesting are briefly discussed.

Circulating tumor DNA association with residual cancer burden after neoadjuvant chemotherapy in triple-negative breast cancer in TBCRC 030

BACKGROUND

We aimed to examine circulating tumor DNA (ctDNA) and its association with residual cancer burden (RCB) using an ultrasensitive assay in patients with triple-negative breast cancer (TNBC) receiving neoadjuvant chemotherapy.

PATIENTS AND METHODS

We identified responders (RCB 0/1) and matched non-responders (RCB 2/3) from the phase II TBCRC 030 prospective study of neoadjuvant paclitaxel versus cisplatin in TNBC. We collected plasma samples at baseline, 3 weeks and 12 weeks (end of therapy). We created personalized ctDNA assays utilizing MAESTRO mutation enrichment sequencing. We explored associations between ctDNA and RCB status and disease recurrence.

RESULTS

Of 139 patients, 68 had complete samples and no additional neoadjuvant chemotherapy. Twenty-two were responders and 19 of those had sufficient tissue for whole-genome sequencing. We identified an additional 19 non-responders for a matched case-control analysis of 38 patients using a MAESTRO ctDNA assay tracking 319-1000 variants (median 1000 variants) to 114 plasma samples from 3 timepoints. Overall, ctDNA positivity was 100% at baseline, 79% at week 3 and 55% at week 12. Median tumor fraction (TFx) was 3.7 × 10-4 (range 7.9 × 10-7-4.9 × 10-1). TFx decreased 285-fold from baseline to week 3 in responders and 24-fold in non-responders. Week 12 ctDNA clearance correlated with RCB: clearance was observed in 10 of 11 patients with RCB 0, 3 of 8 with RCB 1, 4 of 15 with RCB 2 and 0 of 4 with RCB 3. Among six patients with known recurrence, five had persistent ctDNA at week 12.

CONCLUSIONS

Neoadjuvant chemotherapy for TNBC reduced ctDNA TFx by 285-fold in responders and 24-fold in non-responders. In 58% (22/38) of patients, ctDNA TFx dropped below the detection level of a commercially available test, emphasizing the need for sensitive tests. Additional studies will determine whether ctDNA-guided approaches can improve outcomes.

[Status of HVPG clinical application in China in 2021]

Objective: The investigation and research on the application status of Hepatic Venous Pressure Gradient (HVPG) is very important to understand the real situation and future development of this technology in China. Methods: This study comprehensively investigated the basic situation of HVPG technology in China, including hospital distribution, hospital level, annual number of cases, catheters used, average cost, indications and existing problems. Results: According to the survey, there were 70 hospitals in China carrying out HVPG technology in 2021, distributed in 28 provinces (autonomous regions and municipalities directly under the central Government). A total of 4 398 cases of HVPG were performed in all the surveyed hospitals in 2021, of which 2 291 cases (52.1%) were tested by HVPG alone. The average cost of HVPG detection was (5 617.2±2 079.4) yuan. 96.3% of the teams completed HVPG detection with balloon method, and most of the teams used thrombectomy balloon catheter (80.3%). Conclusion: Through this investigation, the status of domestic clinical application of HVPG has been clarified, and it has been confirmed that many domestic medical institutions have mastered this technology, but it still needs to continue to promote and popularize HVPG technology in the future.

Bifocal 532/1064 nm alternately illuminated photoacoustic microscopy for capturing deep vascular morphology in human skin

BACKGROUND

As a promising technology, photoacoustic microscopy (PAM) plays a critical role in diagnosis and assessment of dermatological conditions by providing subtle vascular networks non-invasively. However, the established PAMs are insufficient for clinical dermatology when faced with complex structures of human skin instead of animal models owing to high melanin content and superimposed vasculature for Asians, which cannot balance the spatial resolution and the imaging depth.

OBJECTIVES

To evaluate the ability of bifocal 532/1064-nm alternately illuminated photoacoustic microscopy (BF-PAM) to non-invasively reveal the morphological structure of human skin for improving the diagnosis and therapeutic efficacy of skin diseases.

METHODS

A BF-PAM was developed to capture biopsy-like information of human skin from epidermis to hypodermis. The optical foci of the two excitation beams are staggered in the axial direction to form an extended depth-of-field, which can maintain the lateral resolution and the contrast of PA image.

RESULTS

The imaging capability of the BF-PAM was demonstrated by depicting the vascular morphology of multilayered skin with imaging depth of ˜3 mm. Furtherly, vascular malformations in port-wine stains skin were quantitatively assessed without the need for any contrast agent, and the distribution, depth and diameter of the ectatic vessels can determine an optimal treatment protocol for port-wine stains lesions.

CONCLUSIONS

The quantitative vascular morphology in the dermis can be used to accurately assess vascular characteristics, in which case it enables clinicians to determine optimum treatment parameters in individual patients. As a non-invasive imaging technique, BF-PAM holds great potential to provide objective assessment to enhance the therapeutic efficacy.

ETHICAL STATEMENT

The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Chinese Ethics Committee of Registering Clinical Trials (ChiECRCT20200184) and registered with Chinese Clinical Trial Registry (ChiCTR2000034400). Before skin imaging, written informed consent was taken from all individual participants.

Expression of lncRNA AK058003 in esophageal carcinoma and analysis of its intervention effect

OBJECTIVE

The aim of this study was to investigate the expression of long non-coding ribonucleic acid (lncRNA) AK058003 in esophageal carcinoma (EC) tissues, and to analyze its intervention effect.

PATIENTS AND METHODS

The expression of lncRNA AK058003 in EC tissues and para-carcinoma tissues from 130 EC patients was detected via quantitative Polymerase Chain Reaction (qPCR). EC cell lines were selected for exogenous interference in lncRNA AK058003. Subsequently, the expression of lncRNA AK058003 in normal esophageal epithelial cell line (Het-1A) and EC cell lines (EC109, EC9706, KYSE-150, KYSE-30, and TE-1) was detected by qPCR. EC9706 cell lines with the highest expression of lncRNA AK058003 were selected and transfected with lncRNA AK058003 siRNA and lncRNA AK058003 control, respectively. After transfection, the expression of lncRNA AK058003 was determined using PCR. The changes in cell growth and proliferation were analyzed via cell growth curve and cell cycle assay. Meanwhile, the changes in cell migration and invasion were analyzed through wound healing assay. Protein expressions of matrix metalloproteinase-1 (MMP1) and MMP2 were determined by Western blot. Clinical data were collected from EC patients, and the association between lncRNA AK058003 expression and tumor-node-metastasis (TNM) stage was finally analyzed.

RESULTS

LncRNA AK058003 was highly expressed EC tissues compared with para-carcinoma tissues (p<0.01). Compared with Het-1A cells, the expression of lncRNA AK058003 was significantly higher in EC109, EC9706, KYSE-150, KYSE-30, and TE-1 cells, with highest level in EC9706 cells (p<0.05). The expression of lncRNA AK058003 remarkably declined in lncRNA AK058003 siRNA group compared with lncRNA AK058003 control group (p<0.001). Compared with lncRNA AK058003 control group, the proliferation of EC cells was significantly weakened in lncRNA AK058003 siRNA group, with the greatest difference at 3 d. Flow cytometry results revealed that cell cycle was arrested in G0/G1 phase in lncRNA AK058003 siRNA group. Wound healing assay indicated that the intercellular distance became large, and cell migration ability was evidently enhanced in lncRNA AK058003 siRNA group with time (p<0.05). Besides, the protein expressions of MMP1 and MMP2 were remarkably lower in lncRNA AK058003 siRNA group than those in lncRNA AK058003 control group. This indicated remarkably declined invasion and metastasis ability. In addition, the postoperative prognosis was significantly worse in patients with higher expression of lncRNA AK058003 (p<0.05). All these findings suggested that lncRNA AK058003 could serve as a biomarker for EC prognosis.

CONCLUSIONS

LncRNA AK058003 is highly expressed in EC patients, which promotes proliferation, migration, invasion, and metastasis of EC cells. In addition, the postoperative prognosis of EC patients with high expression of lncRNA AK058003 is relatively poor.

Regulating heat conduction of complex networks by distributed nodes masses

Developing efficient strategy to regulate heat conduction is a challenging problem, with potential implication in the field of thermal materials. We here focus on a potential thermal material, i.e. complex networks of nanowires and nanotubes, and propose a model where the mass of each node is assigned proportional to its degree with [Formula: see text], to investigate how distributed nodes masses can impact the heat flow in a network. We find that the heat conduction of complex network can be either increased or decreased, depending on the controlling parameter [Formula: see text]. Especially, there is an optimal heat conduction at [Formula: see text] and it is independent of network topologies. Moreover, we find that the temperature distribution within a complex network is also strongly influenced by the controlling parameter [Formula: see text]. A brief theoretical analysis is provided to explain these results. These findings may open up appealing applications in the cases of demanding either increasing or decreasing heat conduction, and our approach of regulating heat conduction by distributed nodes masses may be also valuable to the challenge of controlling waste heat dissipation in highly integrated and miniaturized modern devices.

Thermal-siphon phenomenon and thermal/electric conduction in complex networks

In past decades, a lot of studies have been carried out on complex networks and heat conduction in regular lattices. However, very little attention has been paid to the heat conduction in complex networks. In this work, we study (both thermal and electric) energy transport in physical networks rewired from 2D regular lattices. It is found that the network can be transferred from a good conductor to a poor conductor, depending on the rewired network structure and coupling scheme. Two interesting phenomena were discovered: (i) the thermal-siphon effect—namely the heat flux can go from a low-temperature node to a higher-temperature node and (ii) there exits an optimal network structure that displays small thermal conductance and large electrical conductance. These discoveries reveal that network-structured materials have great potential in applications in thermal-energy management and thermal-electric-energy conversion.

A polarization propagation mechanism of Fe and Cu atoms co-doped in two-dimensional-Si3N4

Fe and Cu atoms doped into two dimensional (2D) Si₃N₄ honeycomb structures exhibit magnetic anisotropy, and planar spin-polarization propagation.

Influence of the degree of a complex network on heat conduction

Devices made of nanotubes and nanowires networks are of great interest for applications and have caught increasing attention in recent years. In this work, we study heat conduction in a network model with nodes being atoms and links being one-dimensional chains of atoms. It is found that heat conduction in the complex network is fundamentally different from that of regular lattices. It depends very sensitively on the average degrees of complex networks and the degrees of nodes that are attached to the two heat baths. For example, when the two heat source nodes have the same degree k_{0}, the heat flux reaches a maximum at an optimized value of k_{0} and decreases with the increase of the average degree 〈k〉. In other words, the source nodes with optimal degree k_{0} and the sparse network are more favorable to heat flux. Thermal rectification effect is found when the two heat source nodes have different degrees or the network model has multiple heat source nodes. Theoretical analysis is provided to explain the numerical results.

Unification of catalytic oxygen reduction and hydrogen evolution reactions: highly dispersive Co nanoparticles encapsulated inside Co and nitrogen co-doped carbon

The elaborately synthesized Co nanoparticles encapsulated inside Co and nitrogen co-doped carbon catalysts with homogenous distribution of Co NPs exhibit evidently outstanding performances toward ORR/HER.

Synthesized ultrathin MoS2 nanosheets perpendicular to graphene for catalysis of hydrogen evolution reaction

The S atoms bind to active sites of RGO for the nucleation of MoS₂ and its subsequent growth perpendicular to RGO.

Rescue from dominant follicle atresia by follicle-stimulating hormone in mice

We investigated the effects of follicle-stimulating hormone (FSH) on atresia of the dominant follicle and changes in relevant apoptosis genes in granulosa cells of dominant follicles regulated by FSH in vivo. Four-week-old mice were administered FSH by intraperitoneal injection to induce follicular maturation. Granulosa cells of dominant follicles were collected at 48, 72, and 96 h after the first FSH injection. Phosphate-buffered saline was injected as a control. The mRNA levels of relevant granulosa cell apoptosis genes were examined by real-time quantitative polymerase chain reaction, and apoptosis of granulosa cells in dominant ovarian follicles was determined by the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Apoptosis in granulosa cells of dominant follicles was almost TUNEL-negative at 48, 72-66, 72, and 96-90 h after the first FSH injection, but granulosa cell apoptosis in dominant follicles was clearly detected at 96, 102, and 102-96 h by TUNEL. The BIM, caspase-3, and caspase-9 mRNA expression levels were significantly lower after FSH treatment at 72-66 and 96-90 h, compared with that at 72 and 96 h (P < 0.05). Caspase-8 and FasL mRNA expressions did not respond to FSH. FSH rescued granulosa cells from apoptosis when the relevant apoptosis genes were upregulated in early atretic follicles. FSH did not rescue granulosa cells from apoptosis if the DNA was cut into fragments by endonucleases. Thus, the rescue by FSH of granulosa cells from apoptosis and dominant follicle atresia may be accomplished by inhibition of apoptosis in mitochondria.

Micro-Raman spectroscopy study of the effect of Mid-Ultraviolet radiation on erythrocyte membrane

Mid-Ultraviolet (UVB) has a significant influence on human health. In this study, human erythrocytes were exposed to UVB to investigate the effects of UVB radiation on erythrocytes membrane. And Micro-Raman spectroscopy was employed to detect the damage. Principal component analysis (PCA) was used to classify the control erythrocytes and the irradiated erythrocytes. Results showed that the erythrocytes membrane was damaged by Mid-Ultraviolet (UVB) radiation. The intensity of the Raman peaks at 1126 cm(-1) and 1082 cm(-1) were used to calculate the Longitudinal Order-Parameters in Chains (S(trans)) which can present the liquidity and ionic permeability of erythrocyte membrane. After UVB radiation for 30 min, both the liquidity and ionic permeability decreased. At the same time, the intensity of the peaks at 1302 cm(-1) (α-helix), 1254 cm(-1) (random coil), 1452 cm(-1) and 1430 cm(-1) (CH(2)/CH(3) stretch) have also changed which indicated the membrane protein also been damaged by UVB. In the whole process of radiation, the more UVB radiation dose the more damage on the erythrocyte membrane.

Defect Energy Levels in HfO2, ZrO2, La2O3 and SrTiO3

Defect energy levels of oxygen vacancies in various high K oxides HfO2, ZrO2, La2O3 and SrTiO3 have been calculated using methods which give the correct band gap, such as the screened exchange and weighted density approximation.

Chemokines stimulate human T lymphocyte transendothelial migration to utilize VLA-4 in addition to LFA-1

Lymphocyte infiltration in inflammation is induced by the dual actions of chemokines and cell adhesion molecules. The role of LFA-1 and VLA-4 in chemokine-induced T cell transendothelial migration (TEM) across cytokine-activated endothelium has not been examined. LFA-1, but not VLA-4, mediated blood T cell TEM to RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and stromal cell-derived factor-1 (SDF-1), and across tumor necrosis factor alpha (TNF-alpha) or interferon-gamma (IFN-gamma) -stimulated endothelial cells (EC). Chemokine stimulation in combination with TNF-alpha activation of EC induced TEM, which was partially mediated by VLA-4. SDF-1 increased a beta1-integrin activation epitope on T cells and enhanced VLA-4-mediated adhesion. Thus, LFA-1 mediates TEM under most conditions, but VLA-4 can also mediate TEM, although, in contrast to LFA-1, this requires exogenous chemokines and EC activation. In addition, an LFA-1- and VLA-4-independent pathway of lymphocyte TEM can also be induced by SDF-1.

Ethanol inhibition of adenosine 5'-triphosphate-activated current in freshly isolated adult rat hippocampal CA1 neurons

The effect of ethanol on current activated by extracellular adenosine 5'-triphosphate (ATP) was studied in freshly isolated adult rat hippocampal CA1 neurons using whole-cell patch-clamp recording. ATP activated an inward current with an EC(50) value of 18 microM. The inward current was also activated by 2-methylthio ATP (2-MeSATP) and alpha,beta-methylene ATP (alpha,beta-MeATP), inhibited by pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), and potentiated by Zn(2+). Ethanol inhibited current activated by 10 microM ATP with an IC(50) value of 83 mM in a voltage-independent manner. Ethanol, 100 mM, shifted the ATP concentration-response curve to the right, increasing the EC(50) value for ATP from 18 to 33 microM, but did not reduce the maximal response to ATP. The results suggest that ethanol can inhibit the function of P2X receptors in adult rat hippocampal neurons by decreasing the apparent affinity of the binding site for ATP.

Inhibition by ethanol of rat P2X(4) receptors expressed in Xenopus oocytes

1. The effect of ethanol on the function of P2X(4) receptors expressed in Xenopus oocytes was studied using two-electrode voltage-clamp recording. 2. The amplitude of current activated by 1 microM ATP was decreased by ethanol in a concentration-dependent manner over the concentration range 1 - 500 mM. The concentration of ethanol that produced 50% inhibition (IC(50)) of current activated by 1 microM ATP was 58 mM. 3. Ethanol inhibition of ATP-activated current was not dependent on membrane potential from -60 to +20 mV, and ethanol did not change the reversal potential of ATP-activated current. 4. Ethanol, 50 mM, shifted the ATP concentration-response curve to the right, increasing the EC(50) for ATP from 9.1 to 16.0 microM, but did not reduce the maximal response to ATP. 5. The results suggest that ethanol may inhibit P2X(4) receptors by decreasing the apparent affinity of the binding site for ATP. 6. Since the P2X(4) receptor is the most abundant P2X subunit in the brain, these receptors could be important effectors of ethanol action in the central nervous system.

Regulation of chemokine-induced transendothelial migration of T lymphocytes by endothelial activation: differential effects on naive and memory T cells

Human T lymphocyte transendothelial migration (TEM) was examined in response to chemokines across cytokine-activated endothelium. Monocyte chemotactic protein-1 (MCP-1), RANTES, and macrophage inflammatory protein-1alpha (MIP-1alpha) induced TEM by memory T cells, while stromal cell-derived factor-1 (SDF-1) induced TEM by both naive and memory T cells. Tumor necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1) increased endothelial adhesion molecule (CAM) expression, whereas interferon-gamma (IFN-gamma) induced little up-regulation of CAM. However, both TNF-alpha and IFN-gamma strongly facilitated T cell migration, which was completely inhibited by pertussis toxin and both greatly increased TEM to RANTES, MIP-1alpha, and SDF-1 selectively of memory but not naive T cells. Thus, the dual selective effect on memory T cells of endothelial activation and these chemokines promotes the preferential recruitment of memory T cells to inflammatory sites. However, the enhanced chemokine-induced migration by memory T cells across activated endothelium appears to be independent of the increase in endothelial CAM expression. G-protein-linked stimuli may play an important part in T cell TEM across cytokine-activated endothelium.

[Clinical observation on 51 patients of acute myocardial infarction treated with thrombolytic therapy combined with Chinese herbal medicine]

OBJECTIVE

To assess the efficacy of thrombolytic therapy combined with Chinese herbal medicine (CHM) in treating acute myocardial infarction (AMI).

METHODS

One hundred and one cases of AMI were divided randomly into two groups. The treated group treated with thrombolytic therapy combined with CHM and the control group treated with thrombolytic therapy alone. The criteria of patency of coronary artery were conducted according to the referential standard of thrombolytic therapy in treating AMI introduced by Chinese Angiocardiopathy Medical Journal, 1991.

RESULTS

The patency rate of coronary artery of the two groups were 68.63% and 56.00%, the four-week mortality 3.92% and 10.00%, hemorrhage occurrence 1.96% and 10.00%, congestive heart failure occurrence 5.88% and 16.00%, severe arrhythmia occurrence 11.76% and 22.00%, and the shock occurrence 3.92% and 8.00% respectively. The difference between the two groups was significant, P < 0.01, P < 0.05.

CONCLUSION

The effect of the treated group was better and the complication occurrence of the treated group was lower than those of the control group.

Differential modulation by copper and zinc of P2X2 and P2X4 receptor function

Differential Modulation by Copper and Zinc of P2X2 and P2X4 Receptor Function. The modulation by Cu2+ and Zn2+ of P2X2 and P2X4 receptors expressed in Xenopus oocytes was studied with the two-electrode, voltage-clamp technique. In oocytes expressing P2X2 receptors, both Cu2+ and Zn2+, in the concentration range 1-130 microM, reversibly potentiated current activated by submaximal concentrations of ATP. The Cu2+ and Zn2+ concentrations that produced 50% of maximal potentiation (EC50) of current activated by 50 microM ATP were 16.3 +/- 0.9 (SE) microM and 19.6 +/- 1.5 microM, respectively. Cu2+ and Zn2+ potentiation of ATP-activated current was independent of membrane potential between -80 and +20 mV and did not involve a shift in the reversal potential of the current. Like Zn2+, Cu2+ increased the apparent affinity of the receptor for ATP, as evidenced by a parallel shift of the ATP concentration-response curve to the left. However, Cu2+ did not enhance ATP-activated current in the presence of a maximally effective concentration of Zn2+, suggesting a common site or mechanism of action of Cu2+ and Zn2+ on P2X2 receptors. For the P2X4 receptor, Zn2+, from 0.5 to 20 microM enhanced current activated by 5 microM ATP with an EC50 value of 2.4 +/- 0.2 microM. Zn2+ shifted the ATP concentration-response curve to the left in a parallel manner, and potentiation by Zn2+ was voltage independent. By contrast, Cu2+ in a similar concentration range did not affect ATP-activated current in oocytes expressing P2X4 receptors, and Cu2+ did not alter the potentiation of ATP-activated current produced by Zn2+. The results suggest that Cu2+ and Zn2+ differentially modulate the function of P2X2 and P2X4 receptors, perhaps because of differences in a shared site of action on both subunits or the absence of a site for Cu2+ action on the P2X4 receptor.

On the analysis of neural networks with asymmetric connection weights or noninvertible transfer functions

This paper extends the energy function to the analysis of the stability of neural networks with asymmetric interconnections and noninvertible transfer functions. Based on the new energy function, stability theorems and convergent criteria are derived which improve the available results in the literature. A simpler proof of a previous result for complete stability is given. Theorems on complete stability of neural networks with noninvertible output functions are presented.

[Origin of nitric oxide synthase positive nerve fibers at zusanli area in rats]

OBJECTIVE

To find the origin of nitric oxide synthase (NOS) positive nerve fiber at the area around Zusanli point(St. 36).

METHODS

The combined method of retrograde transport of horse radish peroxidase and nicotinamide adenosine dinucleotide phosphate diaphorase were adopted.

RESULTS

Some peripheral processes of NOS positive neurons were distributed in the Zusanli point from the ganglia of L4 to S1, and some were projected from the lamina IX of L4 to S1 in spinal cord.

CONCLUSION

The distributions of NOS positive nerve fibers in the, Zusanli area might be one of the morphological foundations of acupuncture effect of Zusanli point.

Cancer gene therapy by direct tumor injections of a nonviral T7 vector encoding a thymidine kinase gene

Previously, we described a nonviral cytoplasmic gene therapy vector system based on the T7 autogene concept. This system has been shown to achieve rapid and high levels of gene expression in a variety of animal cells and tissues. To test the utility of the system in vivo tumor ablation, a T7 cancer gene therapy plasmid vector, pT7T7/T7TK, was constructed. This nonviral vector contains a T7 autogene, T7T7, and a human herpes simplex virus thymidine kinase (HSV-TK) gene driven by a second T7 promoter (T7TK). When co-transfected with T7 RNA polymerase (T7 RNAP) into cultured human osteosarcoma 143B cells, abut 10-20% of the cells were found to express HSV-TK, and more than 90% of the cells were killed in the presence of 1 microM ganciclovir (GCV) within 4 days after DNA transfection. The increase in killing above the transfection frequency is due to a "bystander" effect among transfected and untransfected 143B cells. Direct injections of pT7T7/T7TK into 143B tumors grown in nude mice resulted in TK gene expression in tumor cells located near the injection sites as revealed by the immunohistochemical staining. Repeated tumor injections of the pT7T7/T7TK vector and intraperitoneal (i.p.) injections of GCV resulted in inhibition of tumor growth and in tumor shrinkage in 6 out of 10 treated nude mice. Three of those six tumors fully regressed shortly after the end of the GCV injections. All of the full tumor regressions were found to be permanent and no apparent tumor relapses were observed for the rest of the lives of the treated nude mice after the initial tumor ablations. These results, combined with the nonviral and rapid cytoplasmic gene expression features, suggest that the T7 vector may be a good candidate for cancer gene therapy and other medical and biological applications.

[Distribution and ischemia-induced changes of nitric oxide synthase-positive neurons in the cingulate areas in rats]

Distribution of nitric oxide synthase (NOS)-positive neurons of cingulate areas and its changes following bilateral common carotid artery occlusion were investigated with nicotinamide adenosine dinucleotide phosphate diaphoras (NADPH-d) reaction. Positively stained NOS-neurons were observed in the areas 24, 32, and 25 of the anterior cingulate cortex, and in the areas 23 and 29 of the posterior cingulate cortex. After bilateral common carotid artery occlusion, the results showed that the NOS-positive neurons increased markedly in the areas 24, 32, 25, 23 and 29 of the cingulate cortex (P < 0.01).

A novel nonviral cytoplasmic gene expression system and its implications in cancer gene therapy

We recently have developed a unique cytoplasmic transient gene expression system based on cotransfection of target cells with bacteriophage T7 RNA polymerase (RNAP) and plasmid DNA vectors containing a T7 autogene. Because this T7 system is self-initiating, self-maintaining, and requires no cellular factors for transcription, it is therefore likely to function in any mammalian cell with any gene both in vitro and, more importantly, in vivo. In this study we demonstrate that the T7 DNA vector and T7 RNAP could be efficiently codelivered to cultured cells by lipofection. Different target genes were expressed by the T7 system in a wide variety of mammalian cells including several tumor cell lines. Gene expression could be detected in more than 30% of the cells of some tumor cell lines transiently transfected by the T7 vector. Average activity of the reporter enzyme (luciferase) expressed by a transfected cell was relatively constant regardless of the cell line used. When a T7-luciferase vector was directly injected into various tissues of mice without the use of liposomes, luciferase activity could be found in the injected liver, muscle, brain and tail connective tissues. The luciferase levels expressed by the T7 system were found to be up to 200-fold higher, depending upon the injected tissues, than levels achieved with a traditional nuclear gene expression vector. Direct tumor injection with a T7-beta-galactosidase (beta-gal) construct resulted in beta-gal gene expression in tumor cells near the injection sites. In addition, direct injection of the T7 system in mice did not generate detectable quantities of antibodies against the T7 RNAP. These results suggest that this gene expression system may be useful in many different medical applications such as cancer gene therapies and DNA vaccination, where transient but rapid and efficient gene expression is required.

A self-initiating eukaryotic transient gene expression system based on contransfection of bacteriophage T7 RNA polymerase and DNA vectors containing a T7 autogene

A novel cytoplasmic gene expression system has been developed. This system differs from other expression systems in that it relies on the co-delivery of plasmid DNA and T7 RNA polymerase (RNAP) during transfection. The plasmid contains a T7 RNAP gene driven by the T7 promoter (T7 autogene) and a functional/reporter gene driven by another T7 promoter (T7T7/T7-gene construct). Once this DNA-enzyme complex is introduced into eukaryotic cells, the transcription of the T7 RNAP and the functional/reporter genes is initiated by the co-delivered T7 RNAP. The T7 RNAP, which is responsible for the initiation and maintenance of expression of both T7 and functional/reporter genes, is replenished by translation of newly synthesized T7 mRNA. This T7 system was designed in such a manner that the expression of the functional/reporter genes can occur in the cytoplasm and does not require any nuclear involvement. When transfected by either a pT7T7/T7Luc or a pT7T7/T7hGH plasmids with the cointroduced T7 RNAP, mouse L cells were found to express high levels of luciferase immediately after transfection, apparently due to the cytoplasmic gene expression; the expression of human growth hormone (hGH) could be sustained for at least 6 days. Both T7 and hGH mRNA were expressed by the cells transfected with pT7T7/T7hGH. These results suggest that this cytoplasmic expression system may be used for certain targets of somatic gene therapy.