[Clinicopathological factors and clinical significance of No.12b lymph node metastasis in gastric antrum cancer].

Objective: To investigate the clinicopathological factors and clinical significance of (micro)metastasis in No.12b lymph node in patients with gastric antrum cancer. Methods: This was a retrospective cohort study of data of 242 patients with gastric adenocarcinoma without distant metastasis, complete follow-up data, and no preoperative anti-tumor therapy or history of other malignancies. All study patients had undergone radical gastrectomy (at least D2 radical range) + No.12b lymph node dissection in the Department of Gastric Surgery of Liaoning Cancer Hospital from January 2007 to December 2012. Immunohistochemical staining with antibody CK8/18 was used to detect micrometastasis to lymph nodes. Patients with positive findings on hematoxylin and eosin stained specimens and/or CK8/18 positivity in No.12b lymph node were diagnosed as having No.12b (micro)metastasis and included in the No.12b positive group. All other patients were classified as 12b negative. We investigated the impact of No.12b (micro)metastasis by comparing the clinicopathological characteristics and recurrence free survival (RFS) of these two groups of patients and subjecting possible risk factors to statistical analysis. Results: Traditional hematoxylin-eosin staining showed that 15/242 patients were positive for No.12b lymph nodes and 227 were negative. A total of 241 negative No. 12b lymph nodes were detected. Immunohistochemical testing revealed that seven of these 241 No.12b lymph nodes (2.9%) were positive for micrometastasis. A further seven positive nodes were identified among the 227 nodes (3.1%) that had been evaluated as negative on hematoxylin-eosin-stained sections. Thus, 22 /242 patients' (9.1%) No.12b nodes were positive for micrometastases, the remaining 220 (90.9%) being negative. Factor analysis showed that No.12b lymph node (micro) metastasis is associated with more severe invasion of the gastric serosa (HR=3.873, 95%CI: 1.676-21.643, P=0.006), T3 stage (HR=1.615, 95%CI: 1.113-1.867, P=0.045), higher N stage (HR=1.768, 95%CI: 1.187-5.654, P=0.019), phase III of TNM stage (HR=2.129, 95%CI: 1.102-3.475, P=0.046), and lymph node metastasis in the No.1/No.8a/No.12a groups (HR=0.451, 95%CI: 0.121-0.552, P=0.035; HR=0.645, 95%CI:0.071-0.886, P=0.032; HR=1.512, 95%CI: 1.381-2.100, P=0.029, respectively). Survival analysis showed that the 5-year RFS of patients in the No.12b positive group was worse than that of those in the No.12b negative group (18.2% vs. 34.5%, P<0.001). Independent predictors of RFS were poorer differentiation of the primary tumor (HR=0.528, 95%CI:0.288-0.969, P=0.039), more severe serous invasion (HR=1.262, 95%CI:1.039-1.534, P=0.019), higher T/N/TNM stage (HR=4.880, 95%CI: 1.909-12.476, P<0.001; HR=2.332, 95%CI: 1.640-3.317, P<0.001; HR=0.139, 95%CI: 0.027-0.713, P=0.018, respectively), and lymph node metastasis in the No.12a/No.12b group(HR=0.698, 95%CI:0.518-0.941, P=0.018; HR=0.341, 95%CI:0.154-0.758,P=0.008, respectively). Conclusion: Detection of micrometastasis can improve the rate of positive lymph nodes. In patients with gastric antrum cancer, dissection of group No.12b lymph nodes may improve the prognosis of those with intraoperative evidence of tumor invasion into the serosa, more than two lymph node metastases, and suspicious lymph nodes in groups No.1 / No.8a / 12a.

[A multi-center retrospective study of perioperative chemotherapy for gastric cancer based on real-world data].

Objective: To explore the effect of perioperative chemotherapy on the prognosis of gastric cancer patients under real-world condition. Methods: A retrospective cohort study was carried out. Real world data of gastric cancer patients receiving perioperative chemotherapy and surgery + adjuvant chemotherapy in 33 domestic hospitals from January 1, 2014 to January 31, 2016 were collected. Inclusion criteria: (1) gastric adenocarcinoma was confirmed by histopathology, and clinical stage was cT2-4aN0-3M0 (AJCC 8th edition); (2) D2 radical gastric cancer surgery was performed; (3) at least one cycle of neoadjuvant chemotherapy (NAC) was completed; (4) at least 4 cycles of adjuvant chemotherapy (AC) [SOX (S-1+oxaliplatin) or CapeOX (capecitabine + oxaliplatin)] were completed. Exclusion criteria: (1) complicated with other malignant tumors; (2) radiotherapy received; (3) patients with incomplete data. The enrolled patients who received neoadjuvant chemotherapy and adjuvant chemotherapy were included in the perioperative chemotherapy group, and those who received only postoperative adjuvant chemotherapy were included in the surgery + adjuvant chemotherapy group. Propensity score matching (PSM) method was used to control selection bias. The primary outcome were overall survival (OS) and progression-free survival (PFS) after PSM. OS was defined as the time from the first neoadjuvant chemotherapy (operation + adjuvant chemotherapy group: from the date of operation) to the last effective follow-up or death. PFS was defined as the time from the first neoadjuvant chemotherapy (operation + adjuvant chemotherapy group: from the date of operation) to the first imaging diagnosis of tumor progression or death. The Kaplan-Meier method was used to estimate the survival rate, and the Cox proportional hazards model was used to evaluate the independent effect of perioperative chemo therapy on OS and PFS. Results: 2 045 cases were included, including 1 293 cases in the surgery+adjuvant chemotherapy group and 752 cases in the perioperative chemotherapy group. After PSM, 492 pairs were included in the analysis. There were no statistically significant differences in gender, age, body mass index, tumor stage before treatment, and tumor location between the two groups (all P>0.05). Compared with the surgery + adjuvant chemotherapy group, patients in the perioperative chemotherapy group had higher proportion of total gastrectomy (χ(2)=40.526, P<0.001), smaller maximum tumor diameter (t=3.969, P<0.001), less number of metastatic lymph nodes (t=1.343, P<0.001), lower ratio of vessel invasion (χ(2)=11.897, P=0.001) and nerve invasion (χ(2)=12.338, P<0.001). In the perioperative chemotherapy group and surgery + adjuvant chemotherapy group, 24 cases (4.9%) and 17 cases (3.4%) developed postoperative complications, respectively, and no significant difference was found between two groups (χ(2)=0.815, P=0.367). The median OS of the perioperative chemotherapy group was longer than that of the surgery + adjuvant chemotherapy group (65 months vs. 45 months, HR: 0.74, 95% CI: 0.62-0.89, P=0.001); the median PFS of the perioperative chemotherapy group was also longer than that of the surgery+adjuvant chemotherapy group (56 months vs. 36 months, HR=0.72, 95% CI:0.61-0.85, P<0.001). The forest plot results of subgroup analysis showed that both men and women could benefit from perioperative chemotherapy (all P<0.05); patients over 45 years of age (P<0.05) and with normal body mass (P<0.01) could benefit significantly; patients with cTNM stage II and III presented a trend of benefit or could benefit significantly (P<0.05); patients with signet ring cell carcinoma benefited little (P>0.05); tumors in the gastric body and gastric antrum benefited more significantly (P<0.05). Conclusion: Perioperative chemotherapy can improve the prognosis of gastric cancer patients.

Hypoxia-induced LncRNA PCGEM1 promotes invasion and metastasis of gastric cancer through regulating SNAI1.

PURPOSE: Hypoxia is an indispensable factor in the progression of metastasis. Hypoxia inducible factor-1α (HIF-1α), the core element in generating the hypoxia response, induces invasion and metastasis by promoting epithelial-mesenchymal transition (EMT). This study explored the underlying mechanism of hypoxia associated with the invasion and metastasis of gastric cancer (GC). METHODS: Six methods were employed to assess the function of the long noncoding RNA (lncRNA) prostate cancer gene expression marker 1 (PCGEM1) including gene silencing, RT-PCR, the separation of nuclear and cytoplasmic fractions, scrape motility assay, transwell migration assay, and Western-blot. RESULTS: LncRNA PCGEM1 was overexpressed in GC cells and tissues, and was induced by hypoxia in GC cells. Additional experiments confirmed that the knockdown of PCGEM1 significantly repressed the invasion and metastasis of GC cells. SNAI1, a key transcription factor of EMT, was regulated by PCGEM1. Overexpression of SNAI1 rescued the inhibition of PCGEM1-knockdown during the invasion and metastasis of GC cells. In addition, PCGEM1 and SNAI1 jointly affected the biomarkers of EMT. CONCLUSION: Our findings indicated that PCGEM1 is a hypoxia-responsive lncRNA, and contributes to the invasion and metastasis of GC. The potential mechanism is attributed to the regulation of EMT by PCGEM1 and its influence on the expression of SNAI1.

[Clinical value of endoscopicultrsaonography and multi-slice spiral CT in Siewert â ¡and â ¢ type adenocarcinoma of esophagogastric junction].

Objective: To investigate the clinical value of endoscopic ultrasonography (EUS) and Multi-slice Spiral CT (MSCT) in the preoperativestaging of tumor(T) and lymph node (N) metastasis in patients with SiewertⅡand Ⅲ typeadenocarcinoma of esophagogastric junction(AEG). Methods: Clinical data of 145 Siewert Ⅱ and Ⅲ type AEG patientswithout preoperative chemoradiotherapy were retrospectively reviewed. Theyall received preoperative EUS and MSCT examination and underwent surgical resection, and the results of EUS and MSCT were compared with their postoperative pathologic staging. Results: The sensitivity, specificity, and accuracy of EUS for T stage in Siewert Ⅱ and Ⅲ type AEG were higher than those of MSCT. The total accuracy of EUS and MSCT were 90.3% and 63.5%, respectively, and the difference was statistically significant (χ(2)=29.52, P<0.01). The sensitivity of EUS for T1, T2 and T3 were 89.5%, 91.1% and 85.2%, respectively, which were significantly higher than 42.1%, 66.7% and 29.6% of MSCT (χ(2)=9.47, P<0.01 for T1; χ(2)=8.07, P<0.01 for T2; χ(2)=17.40, P<0.01 for T3). In addition, the total accuracy of EUS and MSCT for lymph node metastasis status of Siewert Ⅱ and Ⅲ type AEG were 75.9% and 64.8%, respectively, showing a statistically significant difference(χ(2)=4.23, P=0.04). The sensitivity of EUS for N1 and N2 were 82.1% and 79.2%, respectively, which were significantly higher than 53.6% and 60.4% of MSCT (χ(2)=5.24, P=0.02; χ(2)=4.48, P=0.03). There was no statistical significance for sensitivity of EUS and MSCT in N0 and N3 (P>0.05). Conclusion: EUS diagnosis of T and N staging in Siewert Ⅱ/Ⅲ type AEG showed significantly greater performance than MSCT.

[Analysis of the therapeutic efficacy of radical gastrectomy in Siewert type â ¡ and â ¢ adenocarcinoma of the esophagogastric junction].

OBJECTIVE: To conduct a retrospective analysis of clinicopathological data of patients with Siewert type Ⅱand Ⅲ adenocarcinoma of the esophagogastric junction (AEG), who underwent total gastrectomy (TG) or proximal gastrectomy (PG), to discuss the differences between the two groups in 3-year and 5-year survival rates, postoperative complications and so forth, and to provide theoretical and clinical basis for choosing an ideal surgical approach for patients with Siewert typeⅡ and ⅢAEG. METHODS: The clinical data of 163 patients who underwent radical gastrectomy from January 2006 to December 2008 were analyzed retrospectively. Among them, 85 patients received total gastrectomy (group TG) and 78 patients received proximal gastrectomy (group PG). The 3-year and 5-year survival rates, and postoperative complication rate and mortality rate in the two groups were followed up and compared. RESULTS: The 3-year and 5-year survival rates of the group TG were 71.4% and 47.6%, and those of the group PG were 56.6% and 34.7%, showing a statistically significant difference (χ(2)=4.67, P=0.031;χ(2)=5.17, P=0.023). The postoperative complication rate and mortality rate of the group TG were 12.9% and 4.7% and those of the group PG were 19.2% and 2.6%, with a nonsignificant difference between the two groups (P>0.05). The incidence of reflux esophagitis in the group TG was 1.2%, significantly lower than that of 7.7% in the group PG (P<0.05). CONCLUSIONS: To improve the long-term therapeutic effects, total gastrectomy should be recommended for patients with Siewert type Ⅱ and Ⅲ AEG having high risk factors such as tumor size >3.0 cm, subserosal or serosal invasion, N3 lymph node metastasis and stage Ⅲ tumor. The postoperative complication rate and mortality rate should not be increased, and reflux esophagitis can be effectively avoided in the patients treated with total gastrectomy.

Simulation of sound propagation over porous barriers of arbitrary shapes.

A time-domain solver using an immersed boundary method is investigated for simulating sound propagation over porous and rigid barriers of arbitrary shapes. In this study, acoustic propagation in the air from an impulse source over the ground is considered as a model problem. The linearized Euler equations are solved for sound propagation in the air and the Zwikker-Kosten equations for propagation in barriers as well as in the ground. In comparison to the analytical solutions, the numerical scheme is validated for the cases of a single rigid barrier with different shapes and for two rigid triangular barriers. Sound propagations around barriers with different porous materials are then simulated and discussed. The results show that the simulation is able to capture the sound propagation behaviors accurately around both rigid and porous barriers.

Is postoperative adjuvant chemoradiotherapy efficacious and safe for gastric cancer patients with D2 lymphadenectomy? A meta-analysis of the literature.

BACKGROUND: Adjuvant chemoradiotherapy (CRT) for patients with gastric cancer after D2 lymphadenectomy remains controversial. The objective of the present meta-analysis was to analyze efficacy and safety of postoperative CRT and establish a consensus on whether it is suitable for the patients. METHODS: We searched PubMed, Ovid, Cochrane, and Web of Science. Statistical analysis was carried out by STATA version 12.0 software. The quality of evidence was assessed by Jadad and the Newcastle-Ottawa quality assessment scale. RESULTS: Six studies involving 2135 patients were included for the meta-analysis. The results showed that, compared with non-CRT, postoperative adjuvant CRT was associated with a significant improvement in 5-year overall survival (OS) (HR = 0.79, 95% CI 0.68-0.92, P = 0.002) and 5-year relapse-free survival (RFS) (HR = 0.81, 95% CI 0.70-0.93, P = 0.004). However, there were no differences in distant metastasis (RR = 0.93, 95% CI 0.82-1.06, P = 0.304) and treatment-related toxicity between the two groups. CONCLUSIONS: From the results of our study, postoperative adjuvant CRT may be associated with longer 5-year OS and 5-year RFS in patients with D2 lymphadenectomy, but might not improve 5-year disease-free survival compared to non-CRT. Methodologically high-quality comparative studies are needed for further evaluation.

A computational study of the effect of windscreen shape and flow resistivity on turbulent wind noise reduction.

In this paper, numerical simulations are used to study the turbulent wind noise reduction effect of microphone windscreens with varying shapes and flow resistivities. Typical windscreen shapes consisting of circular, elliptical, and rectangular cylinders are investigated. A turbulent environment is generated by placing a solid circular cylinder upstream of the microphone. An immersed-boundary method with a fifth-order weighted essentially non-oscillatory scheme is implemented to enhance the simulation accuracy for high-Reynolds number flow around the solid cylinder as well as at the interface between the open air and the porous material comprising the windscreen. The Navier-Stokes equations for incompressible flow are solved in the open air. For the flow inside the porous material, a modified form of the Zwikker-Kosten equation is solved. The results show that, on average, the circular and horizontal ellipse windscreens have similar overall wind noise reduction performance, while the horizontal ellipse windscreen with medium flow resistivity provides the most effective wind noise reduction among all the considered cases. The vertical ellipse windscreen with high flow resistivity, in particular, increases the wind noise because of increased self-generation of turbulence.

Expression and distribution of S-100 protein, CD83 and apoptosis-related proteins (Fas, FasL and Bcl-2) in thyroid tissues of autoimmune thyroid diseases.

Previous studies have shown that dendritic cells (DCs) and apoptosis-related proteins play a critical role in the pathogenesis of autoimmune thyroid diseases (ATD). This study was designed to investigate the expression and distribution of S-100 protein, CD83 and apoptosis-related proteins (Fas, FasL and Bcl-2) in the thyroid tissues of ATD and their role in ATD pathogenesis as determined by immunochemical staing techniques and other methods. Pathological tissues of 30 patients with Hashimoto's thyroiditis (HT), 30 patients with Graves' disease (GD) and 30 cases of thyroid follicular adenoma (TFA, as control) were used for this study. A higher expression of S-100 in HT (4.2+/-3.1%) and GD (3.9+/-2.8%) vs TFA (0.95+/-0.64%) (p<0.001). was observed as well as a higher expression of CD83 in HT (22.58+/-13.96% and GD (29.92+/-14.43%) vs TFA (5.19+/-8.08%) (p<0.001). HT thyrocytes adjacent to thyroid infiltrating lymphocytes (TILs) showed greater increases in the levels of Fas and FasL than did the GD thyrocytes while HT TILs exhibited lower expression of Fas and FasL than did the GD TILs. GD thyrocytes expressed increased levels of the antiapoptotic protein Bcl-2 as compared to the low levels detected in HT thyrocytes. An opposite pattern was observed in the TILs in GD (low expression of Bcl-2) and HT (high expression of Bcl-2). The findings suggest that the high expression of DC markers is related to the pathogenesis of HT and GD. Up-regulation of both the number and matured functions of DCs may lead to the presentation of more antigens to lymphocytes which are related to the development of autoimmune thyroid diseases. The regulation of Fas/FasL/Bcl-2 in GD favors apoptosis of infiltrating lymphocytes and thyrocyte survival. The regulation of Fas/FasL/Bcl-2 in HT may promote thyrocyte apoptosis leading to hypothyroidism.

A hemodynamic analysis for determining critical hematocrit in transfusions for sickle cell patients.

Because of complicated rheological issues related with sickle cell blood, there exists a practical need to rationally determine critical hematocrit in transfusions for sickle cell patients. In this research, two major effects, i.e. oxygen concentration and hematocrit, are considered in a theoretical hydrodynamic model incorporating oxygen transport and lubrication theory. The pressure drop depends on the compliance of red blood cells, which changes with oxygen concentration in sickle red cells. Under the assumption that after transfusion, the upper limit of the local resistance of a capillary should not surpass that in the same capillary of normal blood flow, critical hematocrit values with different exchange percentage rates are determined. The current clinical ceiling value of 35 percent for total hematocrit after the transfusion, for the first time, finds its analytical reasoning through mathematical modeling. Plots of critical hematocrit values versus the transfusion exchange percentage are provided in the paper.

Relationship between ABO blood groups and carcinoma of esophagus and cardia in Chaoshan inhabitants of China.

AIM: To study the relationship between ABO blood groups and carcinoma of esophagus and cardia in Chaoshan inhabitants of China, which is a unique Littoral high-risk area of esophageal carcinoma in China. The poor communication and transportation in the past has made Chaoshan a relatively closed area and kept its culture and custure of old China thousand years ago. METHODS: Data on age, sex, ABO blood type and X-ray or pathological diagnose of the patients with carcinoma of esophagus or cardia were collected from the Tumor Hospital. First Affiliated Hospital, Second Affiliated Hospital of Shantou University Medical College; and the Central Hospital of Shantou and the Central Hospital of Jieyang. A total of 6685 patients with esophageal carcinoma (EC) and 2955 patients with cardiac cancer (CC) in Chaoshan district were retrospectively assessed for their association with ABO blood groups. RESULTS: The distribution of ABO blood groups in patients with EC or CC was similar to the normal local population in Chaoshan. However, blood group B in male patients with CC and in the patients with carcinoma in the upper third esophagus was 2.3% and 4.7% higher than the corresponding controls. The relative risk B O was 1.1415 (P<0.05) and 1.2696 (P<0.05), respectively. No relationship was found between ABO blood groups and tumor differentiation. CONCLUSION: ABO blood group B is associated with the incidence of CC in male individuals and carcinoma in the upper third esophagus. The distribution of ABO blood groups varies in the different geographical and ethnic groups. As a result, proper controls are very important for such studies.

Conceptual design of a combined device for normothermia and venous compression.

Hypothermia and venous thrombosis can cause complications during perioperative and postoperative periods which can even be fatal to patients' conditions. Separative devices have currently been used to prevent those two problems. The device proposed here is to combine in a simple unobtrusive fashion the desirable effects of both temperature control and deep venous thrombosis prophylaxis in perioperative patients. A design chart of the new device is provided and design issues are addressed.

Long-term phenotypic correction of rodent hemiparkinsonism by gene therapy using genetically modified myoblasts.

Rat myoblasts were genetically modified to express tyrosine hydroxylase (TH) and produce dopamine in culture. Implanting TH gene-transfected myoblasts into the denervated striatum of 6-OHDA-lesioned rats significantly decreased rotational asymmetry by 50 to approximately 60%. Improvement persisted for up to 13 months. Genetically modified cells could survive and express transgene in the striatum as demonstrated by RT-PCR and immunohistochemical stain-ing. The dopamine content in the striatum tissue of the gene therapy group recovered to 49% of the normal level and was 25-fold higher than that of a control group receiving parental cells. Neither tumor formation nor immunorejection was observed in this study. These results show that myoblasts may be useful as gene carriers for ex vivo gene therapy in the CNS. Gene Therapy (2000) 7, 445-449.

The use of suicide gene systems in vascular cells in vitro.

To investigate the efficiency of suicide gene systems on vascular cells, HSV-tk/GCV and EC-CD/5-FC systems were established on vascular endothelial cells in vitro by retroviral transduction. Both modified cell lines were highly sensitive to prodrugs, the IC50 for GCV was less than 0.4 microM, and IC50 for 5-FC was less than 75 microM, while the parental endothelial cells were insensitive even at the highest concentrations of prodrugs in this experiment. Mixed cellular assay showed that significant bystander effect was exhibited in modified endothelial cells. When only 10% or 30% of the mixed cells were tk positive and exposed to 20 microM GCV for 6 days, more than 60% or 90% of the whole population was killed. Similar result was also found in CD positive cells. These results indicated that both HSV-tk/GCV and EC-CD/5-FC systems could efficiently suppress endothelial cell growth in vitro.

[Experimental treatment for human colorectal carcinoma by tissue type specific expression of herpes simplex virus thymidine kinase gene].

An expression plasmid pCEA-TK, in which HSV-TK gene was under the control of CEA promoter, was constructed. The human colorectal carcinoma cell line LoVo or the human uterine cervical cancer cell line HeLa was co-transfected with pSV2-neo and pCEATK, respectively. After G418 selection, both transgenic cell clones (LoVo/CEATK and HeLa/CEATK) were obtained. LoVo/CEATK cells were 1300 times more sensitive to the cytotoxicity of ganciclovir than LoVo cells. However, the elevation of GCV sensitivity induced by pCEATK gene in HeLa line was only 8 times. Injection of GCV resulted in significant regression of HSV-TK transfected LoVo tumor in nude mice. These data suggested that the expression of TK gene driven by CEA promoter specifically killed CEA-positive colorectal carcinoma cells. Transmission electromicroscopy and DNA fragmentation assay demonstrated that GCV could induce apoptosis in LoVo/CEATK cells. The possibility of the CEATK/GCV system in the treatment of human colorectal carcinoma was discussed.

[Constructure of a recombinant adenovirus vector with HSV-TK and it's killer effect on tumor cells in vitro].

High-titer replication-defective recombinant adenovirus expressing HSV-TK gene was constructed. Firstly, shuttle plasmid pAdCMVTK containing HSV-TK gene and CMV promoter was constructed and then recombined with right arm of adenovirus DNA. Secondly, the positive plaques containing recombinant adenovirus were identified and selected out by PCR and Southern blotting after infection into human embryo kidney 293 cells. The titer of recombinant adenovirus AdCMVTK was determined by plaque forming assay and it was as high as 10(12) pfu/ml. Tumor cells were infected with AdCMVTK and then treated with GCV. Cytotoxic effects were assayed with MTT method. HeLa, A549 and LoVo cells infected with AdCMVTK (M. O. I. = 100) became sensitive to the prodrug GCV, with IC50 less than 4 mumol/L. Significant bystander effect was observed. Results here show that the AdCMVTK/GCV system might be potential in the gene therapy for cancer.

[Expression of foreign tyrosine hydroxylase gene in the rat model of Parkinson's disease].

A total of 75 adult rats were used to produce hemiparkinson's disease (PD) model by unilateral injection of 6-hydroxydopamine (6-OHDA) into the right substantial nigra. Four weeks following the lesions, rats were tested for apomorphine (APO) -induced asymmetric rotation. Only rats that showed more than seven turns per minute were selected as PD models for transplantation. A tyrosine hydroxylase expression plasmid (pSVK3-TH) mixed with lipofectin was transplanted into the right striatum of 15 PD rats. Another 20 PD rats transplanted either with lipofectin or with pSVK3-TH served as controls. Every three days following transplantation, the performance of asymmetric rotation were tested and stained with the TH-immunohistochemistry. Only the animals grafted with pSVK3-TH mixed with lipofectin were found to show the decreased rotational behavior and a few TH-positive cells in the right striatum at the postgraft day 3-12, but not day 18. The results indicate that there exists a correlation between amelioration of asymmetric rotation and the TH gene expression in the denervated striatum. It is suggested that the lipofectin may mediate foreign TH gene expression in the PD rat brain.

[Experimental treatment of brain tumor cells using CD suicide gene].

A negative selection system for glioma gene therapy was established in vitro. C 6 rat glioma cells were infected with recombined retrovirus which contain Escherichia coli cytosine deaminase (EC-CD) gene. The enzyme CD can transform the non-toxic prodrug 5-Fluorocytosine (5-FC) to the highly cellular toxic compound 5-Fluorouracil (5-FU). The growth inhibition studies proved that CD-positive cells were highly sensitive to 5-FC, the IC50 about 3 mumol/L, compared with an IC50 of approximately 6000 mumol/L in parental C 6 cells. Both CD-positive and negative cells were sensitive to 5-FU at very low concentration (IC50 < 1 mumol/L). Mixed cellular assay showed CD-positive cells had "bystander effect" on CD-negative cells when exposed to 5-FC. Our results demonstrate that EC-CD gene should be an efficient suicide gene for the treatment of glioma.

Human interleukin-2 could bind to opioid receptor and induce corresponding signal transduction.

Interleukin-2 (IL-2) was found to have an analgesic effect in the peripheral nervous system. Both electrophysiological and behavioural experiments suggested an anti-noceiceptive effect of IL-2 in animals. Biochemical experiments revealed that IL-2 could displace diprenorphine binding in both NG 108-15 cells and HEK 293 cells transfected with pCDNA3-DOR (delta opioid receptor). Furthermore, IL-2 significantly inhibited cAMP production stimulated by forskolin in both NG 108-15 and transfected HEK 293 cells, indicating that the binding of IL-2 to the delta opioid receptor is functional.