SARS-CoV-2 transmission and control in a hospital setting: an individual-based modelling study

BackgroundDevelopment of strategies for mitigating the severity of COVID-19 is now a top global public health priority. We sought to assess strategies for mitigating the COVID-19 outbreak in a hospital setting via the use of non-pharmaceutical interventions such as social distancing, self-isolation, tracing and quarantine, wearing facial masks/ personal protective equipment. MethodsWe developed an individual-based model for COVID-19 transmission among healthcare workers in a hospital setting. We calibrated the model using data of a COVID-19 outbreak in a hospital unit in Wuhan in a Bayesian framework. The calibrated model was used to simulate different intervention scenarios and estimate the impact of different interventions on outbreak size and workday loss. ResultsWe estimated that work-related stress increases susceptibility to COVID-19 infection among healthcare workers by 52% (90% Credible Interval (CrI): 16.4% - 93.0%). The use of high efficacy facial masks was shown to be able to reduce infection cases and workday loss by 80% (90% CrI: 73.1% - 85.7%) and 87% (CrI: 80.0% - 92.5%), respectively. The use of social distancing alone, through reduced contacts between healthcare workers, had a marginal impact on the outbreak. A strict quarantine policy with the isolation of symptomatic cases and a high fraction of pre-symptomatic/ asymptomatic cases (via contact tracing or high test rate), could only prolong outbreak duration with minimal impact on the outbreak size. Our results indicated that a quarantine policy should be coupled with other interventions to achieve its effect. The effectiveness of all these interventions was shown to increase with their early implementation. ConclusionsOur analysis shows that a COVID-19 outbreak in a hospitals non-COVID-19 unit can be controlled or mitigated by the use of existing non-pharmaceutical measures.

Epidemiological characteristics of COVID-19 in medical staff members of neurosurgery departments in Hubei province: A multicentre descriptive study

BackgroundThe novel coronavirus (SARS-CoV-2) has infected a large number of healthcare workers in Hubei province, China. In addition to infectious and respiratory disease physicians, many doctors in other medical fields have been infected. MethodsWe prospectively collected epidemiological data on medical staff members who are working in neurosurgery departments in 107 hospitals in Hubei province through self-reported questionnaires or telephone interviews. Data of medical staff members with laboratory-confirmed coronavirus disease 2019 (COVID-19) were analysed. The final follow-up date was 1 March 2020. FindingsA total of 5,442 neurosurgery department medical staff members were surveyed. One hundred and twenty cases, involving 54 doctors and 66 nurses, were found to have been infected with SARS-CoV-2. The overall incidence was 2.2%. These cases were concentrated in 26 centres, 16 of which had admitted a total of 59 patients with COVID-19 complicated by craniocerebral disease. Medical staff members in centres receiving COVID-19 patients had a higher risk of contracting infection than those in centres not receiving COVID-19 patients (relative risk: 19.6; 95% confidence interval: 12.6-30.6). Contact with either COVID-19 patients (62.5%, 75/120) or infected colleagues (30.8%, 37/120) was the most common mode of transmission. About 78.3% (94/120) of the infected cases wore surgical masks, whereas 20.8% (25/120) failed to use protection when exposed to the source of infection. Severe infections were observed in 11.7% (14/120) of the cases, with one death (0.8%, 1/120). All the infected medical staff members had been discharged from the hospital. A total of 1,287 medical staff members were dispatched to participate in the frontline response to COVID-19 under level 2 protection of whom one was infected. Medical staff members who took inadequate protection had a higher risk of contracting infection than those using level 2 protection (relative risk: 36.9; 95% confidence interval: 5.2-263.6). ConclusionsNeurosurgical staff members in Hubei province were seriously affected by COVID-19. Level 2 protection and strengthening of protective measures are likely to be effective in preventing medical workers from being infected.

Hospitalization time and outcome in patients with Coronavirus Disease 2019 (COVID-19): analysis data from China

ObjectiveThe mean hospitalization time and outcome among patients with coronavirus disease 2019 (COVID-19) was estimated with the purpose of providing evidence for decision-making in medical institutions and governments in epidemic areas. MethodThe data of COVID-19 patients in china were collected from the websites of provincial and municipal health commissions. The mean hospitalization time and mortality in the mild or severe patients and the mean time from severe to mild illness were calculated by Gaussian mixture modeling. ResultsThe mean hospitalization time among mild patients in Hubei province, other areas except Hubei province, and the national areas was 20.71{+/-} 9.30, 16.86 {+/-} 8.24, and 19.34 {+/-} 9.29 days, respectively. The mean transition time from severe to mild group in the above three areas were 15.00, 17.00, and 14.99 days, respectively. The death rate of mild and severe patients in Hubei province and the national areas were 1.10% and 18.14%, and 1.10% and 17.70%, respectively. Among those patients who died of COVID-19, the mean time from severe transition to death in Hubei province and the national areas was 6.22 {+/-} 5.12 and 6.35 {+/-} 5.27 days, respectively. ConclusionThere were regional differences in the average length of stay between Hubei province and other regions, which may be related to different medical configurations. For those severe patients who died of COVID-19, the average time from hospitalization to death was about one week, and proper and effective treatments in the first week were critical.

SARS-CoV-2 infection in health care workers: a retrospective analysis and a model study

BackgroundThere had been a preliminary occurrence of human-to-human transmissions between healthcare workers (HCWs), but risk factors in the susceptibility for COVID-19, and infection patterns among HCWs have largely remained unknown. MethodsRetrospective data collection on demographics, lifestyles, contact status with infected subjects for 118 HCWs (include 12 COVID-19 HCWs) from a single-center. Sleep quality and working pressure were evaluated by Pittsburgh Sleep Quality Index (PSQI) and The Nurse Stress Index (NSI), respectively. Follow-up duration was from Dec 25, 2019, to Feb 15, 2020. Risk factors and transmission models of COVID-19 among HCWs were analyzed and constructed. FindingsA high proportion of COVID-19 HCWs had engaged in night shift-work (75.0% vs. 40.6%) and felt they were working under pressure (66.7% vs. 32.1%) than uninfected HCWs. COVID-19 HCWs had higher total scores of PSQI and NSI than uninfected HCWs. Furthermore, these scores were both positively associated with COVID-19 risk. An individual-based model (IBM) estimated the outbreak duration among HCWs in a non-typical COVID-19 ward at 62-80 days and the basic reproduction number R0 =1.27 [1.06, 1.61]. By reducing the average contact rate per HCW by a 1.35 factor and susceptibility by a 1.40 factor, we can avoid an outbreak of the basic case among HCWs. InterpretationPoor sleep quality and high working pressure were positively associated with high risks of COVID-19. A novel IBM of COVID-19 transmission is suitable for simulating different outbreak patterns in a hospital setting. FundingFundamental Research Funds for the Central Universities

PPM1D silencing by lentiviral-mediated RNA interference inhibits proliferation and invasion of human glioma cells / 华中科技大学学报（医学）（英德文版）

To construct a lentiviral shRNA vector targeting human protein phosphatase 1D magnesium-dependent (PPM1D) gene and detect its effectiveness of gene silencing in human gliomas, specific siRNA targets with short hairpin frame were designed and synthesized. DNA oligo was cloned into the pFU-GW-iRNA lentiviral expression vector, and then PCR and sequencing analyses were conducted to verify the constructs. After the verified plasmids were transfected into 293T cells, the lentivirus was produced and the titer of virus was determined. Real-time quantitative PCR and Western blot were performed to detect the PPM1D expression level in the infected glioma cells. PCR and Western blot analyses revealed the optimal interfering target, and the virus with a titer of 6×10(8) TU/mL was successfully packaged. The PPM1D expression in human glioma cells was knocked down at both mRNA and protein levels by virus infection. The expression of PPM1D mRNA and protein was decreased by 76.3% and 87.0% respectively as compared with control group. The multiple functions of human glioma cells after PPM1D RNA interference were detected by flow cytometry and cell counting kit-8 (CCK-8). Efficient down-regulation of PPM1D resulted in significantly increased cell apoptosis and reduced cell proliferation and invasion potential in U87-MG cells. We have successfully constructed the lentiviral shRNA expression vector capable of stable PPM1D gene silencing at both mRNA and protein levels in glioma cells. And our data gave evidence that the reduced cell growth observed after PPM1D silencing in glioma cells was at least partly due to increased apoptotic cell death.

Inhibitory effects of TNP-470 in combination with BCNU on tumor growth of human glioblastoma xenografts / 华中科技大学学报（医学）（英德文版）

This study investigated the effect of TNP-470 in combination with carmustine (BCNU) on the growth of subcutaneously implanted human glioblastoma xenografts in nude mice. Human glioblastoma U-251 cells (1×10(7)) were injected into 24 nude mice subcutaneously. The tumor-bearing mice were randomly divided into 4 groups on the seventh day following tumor implantation: TNP-470 group, in which TNP-470 was given 30 mg/kg subcutaneously every other day 7 times; BCNU group, in which 20 mg/kg BCNU were injected into peritoneal cavity per 4 days 3 times; TNP-470 plus BCNU group, in which TNP-470 and BCNU were coadministered in the same manner as in the TNP-470 group and the BCNU group; control group, in which the mice were given 0.2 mL of the mixture including 3% ethanol, 5% acacia and 0.9% saline subcutaneously every other day 7 times. The tumor size and weights were measured. The tumor microvessel density (MVD) was determined by immunostaining by using goat-anti-mouse polyclonal antibody CD105. The results showed that on the 21th day following treatment, the volume of xenografts in the TNP-470 plus BCNU group was (108.93±17.63)mm(3), markedly lower than that in the TNP-470 group [(576.10±114.29)mm(3)] and the BCNU group [(473.01±48.04)mm(3)] (both P<0.01). And the xenograft volume in these 3 treatment groups was even much lower than that in the control group [(1512.61±470.25) mm(3)] (all P<0.01). There was no significant difference in the volume of xenografts between the TNP-470 group and the BCNU group (P>0.05). The inhibition rate of the tumor growth in the TNP-470 plus BCNU group was (92.80±11.37)%, notably higher than that in the TNP-470 group [(61.91±6.29)%] and the BCNU group [(68.73±9.65)%] (both P<0.01) on the 21th day following treatment. There was no significant difference in the inhibition rate of tumor growth between the TNP-470 group and the BCNU group (P>0.05). The MVD of xenografts in the TNP-470 plus BCNU group was decreased significantly as compared with that in the TNP-470 group or the BCNU group (both P<0.05). The MVD of xenografts in the 3 treatment groups was markedly reduced as compared with that in the control group (all P<0.05). No significant changes in weights were observed before and after the treatment in each group (all P>0.05). It was concluded that the combination of TNP-470 and BCNU can significantly inhibit the growth of human glioblastoma xenografts in nude mice without evident side effects.

Inhibitory effects of TNP-470 in combination with BCNU on tumor growth of human glioblastoma xenografts / 华中科技大学学报（医学）（英德文版）

This study investigated the effect of TNP-470 in combination with carmustine (BCNU) on the growth of subcutaneously implanted human glioblastoma xenografts in nude mice. Human glioblastoma U-251 cells (1×10(7)) were injected into 24 nude mice subcutaneously. The tumor-bearing mice were randomly divided into 4 groups on the seventh day following tumor implantation: TNP-470 group, in which TNP-470 was given 30 mg/kg subcutaneously every other day 7 times; BCNU group, in which 20 mg/kg BCNU were injected into peritoneal cavity per 4 days 3 times; TNP-470 plus BCNU group, in which TNP-470 and BCNU were coadministered in the same manner as in the TNP-470 group and the BCNU group; control group, in which the mice were given 0.2 mL of the mixture including 3% ethanol, 5% acacia and 0.9% saline subcutaneously every other day 7 times. The tumor size and weights were measured. The tumor microvessel density (MVD) was determined by immunostaining by using goat-anti-mouse polyclonal antibody CD105. The results showed that on the 21th day following treatment, the volume of xenografts in the TNP-470 plus BCNU group was (108.93±17.63)mm(3), markedly lower than that in the TNP-470 group [(576.10±114.29)mm(3)] and the BCNU group [(473.01±48.04)mm(3)] (both P0.05). The inhibition rate of the tumor growth in the TNP-470 plus BCNU group was (92.80±11.37)%, notably higher than that in the TNP-470 group [(61.91±6.29)%] and the BCNU group [(68.73±9.65)%] (both P0.05). The MVD of xenografts in the TNP-470 plus BCNU group was decreased significantly as compared with that in the TNP-470 group or the BCNU group (both P0.05). It was concluded that the combination of TNP-470 and BCNU can significantly inhibit the growth of human glioblastoma xenografts in nude mice without evident side effects.

Focal cerebral ischemia induces Alzheimer's disease-like pathological change in rats / 华中科技大学学报（医学）（英德文版）

The changes in the tau protein phosphorylation and expression of bcl-2, and bax in rat parietal cortex neurons after focal cerebral ischemia-reperfusion (I/R) were explored, and the relationship between the tau protein phosphorylation and the expression of bax or apoptosis was clarified in order to elucidate the relationship between cerebral infarction and Alzheimer's disease. The rat focal cerebral I/R model was induced by occlusion of the right middle cerebral artery using the intraluminal suture method. The level of tau protein phosphorylation at Ser396, Ser404, Tyr231, Ser199/202 sites and the expression of bcl-2, bax and total tau 5 in rat parietal cortex during focal cerebral ischemia/reperfusion were detected by Western blot. The relationship between the tau protein phosphorylation and the expression of bax, or apoptosis was examined by TUNEL method and double-labeling immunofluorenscence method. The results showed that the level of tau hyperphosphorylation at Ser199 / 202, Ser396, Ser404, Tyr231 sites and the expression levels of bcl-2, and bax were significantly higher in I/R group than in the sham group, but the ratio of bcl-2/bax was decreased. Neuronal apoptosis, bax expression and the tau protein hyperphosphorylation were co-localized. It is suggested that Alzheimer's disease-like pathological changes occur after cerebral I/R. The highly abnormal phosphorylation of tau protein plays a key role in cerebral I/R-induced apoptosis. The cerebral infarction may contribute to Alzheimer's disease occurrence and development.

Superparamagnetic iron oxide labeling of spinal cord neural stem cells genetically modified by nerve growth factor-beta / 华中科技大学学报（医学）（英德文版）

This study established superparamagnetic iron oxide (SPIO)-labeled nerve growth factor-beta (NGF-beta) gene-modified spinal cord-derived neural stem cells (NSCs). The E14 rat embryonic spinal cord-derived NSCs were isolated and cultured. The cells of the third passage were transfected with plasmid pcDNA3-hNGFbeta by using FuGENE HD transfection reagent. The expression of NGF-beta was measured by immunocytochemistry and Western blotting. The positive clones were selected, allowed to proliferate and then labeled with SPIO, which was mediated by FuGENE HD transfection reagent. Prussian blue staining and transmission electron microscopy (TEM) were used to identify the SPIO particles in the cells. The distinctive markers for stem cells (nestin), neuron (beta-III-tubulin), oligodendrocyte (CNPase) and astrocyte (GFAP) were employed to evaluate the differentiation ability of the labeled cells. The immunocytochemistry and western blotting showed that NGF-beta was expressed in spinal cord-derived NSCs. Prussian blue staining indicated that numerous blue-stained particles appeared in the cytoplasma of the labeled cells. TEM showed that SPIO particles were found in vacuolar structures of different sizes and the cytoplasma. The immunocytochemistry demonstrated that the labeled cells were nestin-positive. After differentiation, the cells expressed beta-III-tubulin, CNPase and GFAP. It was concluded that the SPIO-labeled NGF-beta gene-modified spinal cord-derived NSC were successfully established, which are multipotent and capable of self-renewal.

Medical economics research on surgical management of hypertensive cerebral hemorrhage / 中华老年医学杂志

Objective To evaluate the effectiveness among computed tomography-guided aspiration.minimally invasive microsurgery and conventional craniotomy on patients with intracerebral hemorrhage and their quality of life separately.Then to study the cost-effectiveness of the 3 surgical procedures. Methods One hundred and five patients with intracerebral hemorrhages were randomized into 3 groups:conventional group,stereotactic group and key-hole group.Karnofsky Performance Status Scale was examined 3 months after operation,and the cost of hospitahzation was calculated separately,then the cost-effectiveness was compared using cost-utility analysis. Results Costs of 3 procedures were 9741 yuan,7957 yuan and 13256 yuan separately,and Karnofsky Performance Status Scale were 59.7,63.7 and 50.3 separately.When self-care case was achieved in all conventional group,the stereotactic group and key-hole group need to remedy 51 eases and 10 cases separately.and the total cost was 496819 yuan for stereotactic group and 79575 yuan for key-hole group. Conclusions Minimally invasive microsurgery is optimal treatment for intracerebral hemorrhage.

Induction of cytotoxic T-lymphocytes specific for malignant glioma by HLA dimer-based artificial antigen-presenting cells.

AIM: The aim of this study was to investigate the novel approach for targeting malignant glioma. METHODS: Interleukin-13 receptor alpha2 (IL-13Ralpha2)-specific cytotoxic T-cells (CTLs) were induced from the peripheral blood lymphocytes (PBLs) of human leukocyte antigen (HLA)-A2 positive healthy donors by multiple stimulations with artificial antigen-presenting cells (aAPCs) made by coating HLA-A2-Ig/pIL-13Ralpha2(345-354) dimeric complexes, anti-CD28 antibody, and CD83 molecules to cell-sized latex beads. RESULTS: The induced CTLs exhibited a specific lysis against T2 cells pulsed with the peptide pIL-13Ralpha2(345-354) and HLA-A2(+) glioma cells expressing IL-13Ralpha2(345-354), while HLA-A2(-) glioma cell lines that express IL-13Ralpha2(345-354) could not be recognized by the CTLs. The peptide-specific activity was inhibited by the anti-HLA class I monoclonal antibody. CONCLUSIONS: The induced CTLs specific for the IL-13Ralpha2(345-354) peptide could be a potential target of specific immunotherapy for HLA-A2(+) patients with malignant glioma.

Knocking-down of Nogo-A gene expression in PC12 cell line by plasmid-based RNAi / 华中科技大学学报（医学）（英德文版）

To study the inhibitory effect of Nogo-A shRNA on cell line PC12, the Nogo-A shRNA (short hairpin RNA, or shRNA) was designed and synthesized. The annealed shRNA template was inserted into plasmid pGenesil-1 containing enhanced green fluorescent protein (EGFP) gene by gene cloning technique to generate eukaryotic expression vector. The recombinant plasmid was transfected into PC12 cells by lipofecamine2000 and the mRNA and protein expression level of Nogo-A gene was detected by RT-PCR and Western blotting 48 h after the transfection. Gene sequencing showed that that the Nogo-A shRNA eukaryotic expression vector was successfully constructed. No significant change was found in the Nogo-A mRNA and protein expression level in empty vector-transfected group as compared with controls (P>0.05), while the expression level in shRNA-transfected group decreased significantly (P<0.05). It is concluded that the pGenesil-1/Nogo-AshRNA recombinant plasmid can effectively suppress the expression of Nogo-A gene in PC12 cells.

Effect of Rosiglitazone Maleate on inflammation following cerebral ischemia/reperfusion in rats / 华中科技大学学报（医学）（英德文版）

In order to evaluate the neuroprotective effect of Rosiglitazone Maleate (RSG) against brain ischemic injury, the effects of Rosiglitazone Maleate on the inflammation following cerebral ischemia/reperfusion were investigated. Focal cerebral ischemia was induced by the intraluminal thread for cerebral middle artery (MCA) occlusion. Rosiglitazone Maleate at concentrations of 0.5, 2 and 5 mg/kg was infused by intragastric gavage twice immediately and 2 h after MCA occlusion, respectively. The effects of Rosiglitazone Maleate on brain swelling, myeloperoxidase and interleukin-6 mRNA level in brain tissue after MCA occlusion and reperfusion were evaluated. The results showed that as compared with the model control group, RSG (0.5 mg/kg) had no significant influence on brain swelling (P>0.05), but 2 mg/kg and 5 mg/kg RSG could significantly alleviate brain swelling (P<0.05). All different doses of RSG could obviously reduce MPO activity in brain tissue after MCA occlusion and reperfusion in a dose-dependent manner. RSG (0.5 and 2 mg/kg) could decrease the expression levels of IL-6 mRNA in brain tissue after MCA occlusion and reperfusion to varying degrees (P<0.05) with the difference being significant between them. It was concluded that RSG could effectively ameliorate brain ischemic injury after 24 h MCA occlusion and inhibit the inflammatory response after ischemia-reperfusion in this model.

Effect of Rosiglitazone Maleate on Inflammation Following Cerebral Ischemia/Reperfusion in Rats / 华中科技大学学报（医学）（英德文版）

In order to evaluate the neuroprotective effect of Rosiglitazone Maleate (RSG) against brain ischemic injury, the effects of Rosiglitazone Maleate on the inflammation following cerebral ischemia/reperfusion were investigated. Focal cerebral ischemia was induced by the intraluminal thread for cerebral middle artery (MCA) occlusion. Rosiglitazone Maleate at concentrations of 0.5,2 and 5 mg/kg was infused by intragastric gavage twice immediately and 2 h after MCA occlusion,respectively. The effects of Rosiglitazone Maleate on brain swelling, myeloperoxidase and interleukin-6 mRNA level in brain tissue after MCA occlusion and reperfusion were evaluated. The results showed that as compared with the model control group, RSG (0.5 mg/kg) had no significant influence on brain swelling (P＞0.05), but 2 mg/kg and 5 mg/kg RSG could significantly alleviate brain swelling (P＜0.05). All different doses of RSG could obviously reduce MPO activity in brain tissue after MCA occlusion and reperfusion in a dose-dependent manner. RSG (0.5 and 2 mg/kg) could decrease the expression levels of IL-6 mRNA in brain tissue after MCA occlusion and reperfusion to varying degrees (P＜0.05) with the difference being significant between them. It was concluded that RSG could effectively ameliorate brain ischemic injury after 24 h MCA occlusion and inhibit the inflammatory response after ischemia-reperfusion in this model.

Knocking-down of Nogo-A Gene Expression in PC12 Cell Line by Plasmid-based RNAi / 华中科技大学学报（医学）（英德文版）

To study the inhibitory effect of Nogo-A shRNA on cell line PC12, the Nogo-A shRNA (short hairpin RNA, or shRNA) was designed and synthesized. The annealed shRNA template was inserted into plasmid pGenesil-1 containing enhanced green fluorescent protein (EGFP) gene by gene cloning technique to generate eukaryotic expression vector. The recombinant plasmid was transfected into PC12 cells by lipofecamine2000 and the mRNA and protein expression level of Nogo-A gene was detected by RT-PCR and Western blotting 48 h after the transfection. Gene sequencing showed that that the Nogo-A shRNA eukaryotic expression vector was successfully constructed. No significant change was found in the Nogo-A mRNA and protein expression level in empty vector-transfected group as compared with controls (P＞0.05), while the expression level in shRNA-transfected group decreased significantly (P＜0.05). It is concluded that the pGenesil-1/Nogo-AshRNA recombinant plasmid can effectively suppress the expression of Nogo-A gene in PC 12 cells.

Magnetic Resonance Imaging of Transplanted Neural Stem Cells in Parkinson Disease Rats / 华中科技大学学报（医学）（英德文版）

In this study we implanted magnetically labeled neural stem cells (NSCs) in PD rats and then monitored their survival and migration in the host brain by magnetic resonance imaging (MRI).The mesencephalic NSCs were obtained from the brain of SD rats. Superparamagnetic iron oxide (SPIO) was transferred to NSCs by Lipofectamine transfection. Eighteen PD lesioned rats were selected for transplantation by evaluation of their rotational behavior in response to amphetamine and randomly assigned to 3 groups, i.e., sham group, PBS group and NSCs transplanted group, with 6 rats in each group. MR scanning was performed at 1, 2, 4, 6, 8 and 10 week(s) following transplantation.At the meantime, rotational behavior was assessed in each group. Our results showed that SPIO particles were clearly visible with Prissian blue staining in neurospheres and cells derived from NSCs.The rotational behavior of the NSCs transplanted group was remarkably improved compared with that of sham group and PBS group (P＜0.05). In vivo MR tracking of NSCs showed that SPIO labeling led to a strong susceptibility change of signal 1 week after transplantation on T2 weighted images.And a large circular hypointense signal appeared in the transplanted area on T2* gradient echo images.Ten weeks following transplantation, the hypointense signal on T2 weighted and T2* gradient echo images was still displayed. It is concluded that SPIO particles could label NSCs effectively, and MRI detection of SPIO labeled cells is a promising method and novel approach to analyzing the NSCs following transplantation in the treatment of PD.

Magnetic resonance imaging of transplanted neural stem cells in Parkinson disease rats / 华中科技大学学报（医学）（英德文版）

In this study we implanted magnetically labeled neural stem cells (NSCs) in PD rats and then monitored their survival and migration in the host brain by magnetic resonance imaging (MRI). The mesencephalic NSCs were obtained from the brain of SD rats. Superparamagnetic iron oxide (SPIO) was transferred to NSCs by Lipofectamine transfection. Eighteen PD lesioned rats were selected for transplantation by evaluation of their rotational behavior in response to amphetamine and randomly assigned to 3 groups, i.e., sham group, PBS group and NSCs transplanted group, with 6 rats in each group. MR scanning was performed at 1, 2, 4, 6, 8 and 10 week(s) following transplantation. At the meantime, rotational behavior was assessed in each group. Our results showed that SPIO particles were clearly visible with Prissian blue staining in neurospheres and cells derived from NSCs. The rotational behavior of the NSCs transplanted group was remarkably improved compared with that of sham group and PBS group (P < 0.05). In vivo MR tracking of NSCs showed that SPIO labeling led to a strong susceptibility change of signal 1 week after transplantation on T2 weighted images. And a large circular hypointense signal appeared in the transplanted area on T2* gradient echo images. Ten weeks following transplantation, the hypointense signal on T2 weighted and T2* gradient echo images was still displayed. It is concluded that SPIO particles could label NSCs effectively, and MRI detection of SPIO labeled cells is a promising method and novel approach to analyzing the NSCs following transplantation in the treatment of PD.

Effect of wild-type p53 gene transfection on the growth and radiotherapeutic sensitivity of human glioma cells / 华中科技大学学报（医学）（英德文版）

To evaluate the effect of wild-type p53 gene on the growth and radiotherapeutic sensitivity of human glioma cells, plasmid PC53-SN3 carrying wild-type p53 gene was transfected into U251 cells. p53 gene expression in transfected cells was detected by RT-PCR, and the cell growth inhibition and apoptosis in the absence or presence of irradiation were assessed by MTT and flow cytometry. The transfection of p53 gene into U251 cells was confirmed by RT-PCR. MTT showed that p53 gene alone induced strong inhibitory effect on the growth of U251 cells (inhibition rate (IR), (79.60 +/- 5.69)%). The killing effect of irradiation alone on U251 cells was not strong (IR: (17.06 +/- 4.35)% (17.39 +/- 1.67)% (18.73 +/- 4.68)%) and increased with the irradiation doses (3, 6, 9 Gy). When combined treatment of wild-type p53 gene transfection and irradiation was used, the effect was significantly increased (IR:(80.60 +/- 5.35)%. (90.30 +/- 1.67)%, (91.30 +/- 2.01)%). The apoptosis rate of U251 cells induced by p53 gene transfection was 17.38%. The rate induced by irradiation increased (4.61%, 4.84%, 5.40%) with the irradiation doses (3, 6, 9 Gy). The apoptosis rate was also significantly increased (17.80%, 20.03%, 22.34%) after combined treatment of p53 and irradiation with different doses (3, 6, 9 Gy). It is concluded that wild-type p53 gene and irradiation could result in synergistic inhibitory effect on the growth of human glioma cells.

Effect of Wild-type p53 Gene Transfection on the Growth and Radiotherapeutic Sensitivity of Human Glioma Cells / 华中科技大学学报（医学）（英德文版）

To evaluate the effect of wild-type p53 gene on the growth and radiotherapeutic sensitivity of human glioma cells, plasmid PC53-SN3 carrying wild-type p53 gene was transfected into U251cells. p53 gene expression in transfected cells was detected by RT-PCR, and the cell growth inhibition and apoptosis in the absence or presence of irradiation were assessed by MTT and flow cytometry. The transfection of p53 gene into U251 cells was confirmed by RT-PCR. MTT showed that p53 gene alone induced strong inhibitory effect on the growth of U251 cells (inhibition rate (IR):(79.60±5.69) %). The killing effect of irradiation alone on U251 cells was not strong (IR: (17.06±4.35) %, (17.39±1.67) %, (18.73±4.68) %) and increased with the irradiation doses (3,6, 9 Gy). When combined treatment of wild-type p53 gene transfection and irradiation was used,the effect was significantly increased (IR:(80.60±5.35) %, (90.30±1.67) %, (91.30±2.01)%). The apoptosis rate of U251 cells induced by p53 gene transfection was 17.38 %. The rate induced by irradiation increased (4. 61%, 4. 84 %, 5.40 %) with the irradiation doses (3, 6, 9Gy). The apoptosis rate was also significantly increased (17.80 %, 20.03 %, 22.34%) after combined treatment of p53 and irradiation with different doses (3, 6, 9 Gy). It is concluded that wildtype p53 gene and irradiation could result in synergistic inhibitory effect on the growth of human glioma cells.

A combination of flk1-based DNA vaccine and an immunomodulatory gene (IL-12) in the treatment of murine cancer.

AIM: The aim of this study was to investigate the antivasculature effects and the antitumor effects of combining attenuated Salmonella typhimurium vaccine strain encoding murine vascular endothelial growth factor (VEGF) receptor-2 (flk1) with plasmid DNA vector encoding the murine IL-12 (mIL-12) gene. METHODS: Mouse models of Gl261 glioblastoma were treated with combining orally given attenuated Salmonella typhimurium vaccine strain encoding flk1 with direct intratumoral injection of a nonviral plasmid DNA vector encoding the murine IL-12 (mIL-12) gene. The volumes of tumors were observed. Cytolytic T lymphocyte (CTL) response was measured by a 4-hour 51Cr release assay, vessle density and tumor cell proliferation were observed by immunostaining, and tumor apoptosis was determined by TUNEL staining. RESULTS: Compared to mice receiving single agent therapy, received either oral immunization flk1-based vaccine only or the therapeutic gene-IL-12 plasmid DNA only or those in the control group, the combination therapy groups developed a strong CTL response and showed more significantly inhibited tumor growth, apoptosis of tumor cells, and reduced neovascularization and cell proliferation in these mice. CONCLUSIONS: The therapy of attenuated Salmonella typhimurium vaccine strain encoding flk1 combined with the interleukin-12 gene has significant synergistic effect against tumors.