Volume 120  ·   Issue 08  ·  2007

The history of surgery for lung cancer dates back to 73 years ago, in 1933, when Evart Graham performed the first successful pneumonectomy for lung cancer at the Barnes/Jewish Hospital in Saint Louis, Missouri, USA。

Abstract：Background O6-methylguanine-DNA-methyltransferase (MGMT) is a specific DNA revising enzyme transferring alkylated groups from DNA to its cysteine residue to avoid the abnormal twisting of DNA. Therefore, it is one of the drug resistant genes targeted in the treatment of cancer. This study explored the protective effect of MGMT gene transferred into mammalian cells.Methods Mammalian expression vector containing the MGMT gene cloned from human hepatocytes by RT-PCR was constructed and transferred into K562 cells and human peripheral blood mononuclear cells (PBMCs) via liposome, then assayed for gene expression at RNA and protein levels. MTT assay was used to check the drug resistance of cells transfected with MGMT gene.Results MGMT gene was successfully cloned. Real-time PCR showed that the mRNA expression in gene transfected groups in K562 cell line and PBMC were 13.4 and 4.0 times that of the empty vector transfected groups respectively.Results of Western blotting showed distinct higher expression of MGMT in gene transfected group than in other two groups. The IC50 values increased to 7 and 2 times that of the original values respectively in stable transfected K562 cells and transient transfected PBMC.Conclusion The alkylating resistance of eukaryotic cells is enhanced after being transfected with MGMT gene which protein product performs the protective function, and may provide the reference for the protective model of peripheral blood cells in cancer chemotherapy。

Abstract：Background Human β-defensin-3 (HBD3) is an epithelial peptide that has been demonstrated to have a salt-insensitive broad spectrum of potent antimicrobial activity. Expressing antimicrobial peptides in Escherichia coli (E. coli) is very difficult for it can result in death of the bacterial host cells. Our aim was to establish a prokaryotic system expressing soluble HBD3 protein and demonstrate the antimicrobial activity of the expressed protein. We then studied whether the host cells would activate the suicide pathways.Methods We first cloned the complementary DNA coding for the mature chain of HBD3, inserted it into the vector PGEX-KG then transformed E. coli BL21 (DE3) with the appropriate recombinant plasmid. After induction with 0.5 mmol/L isopropyl-1-thio-β-D-galactopyranoside (IPTG) the transformed E. coli produced a recombinant glutathione S-transferase and HBD3 (GST-HBD3) fusion protein. The fusion protein was treated with thrombin to produce pure HBD3 protein then the antimicrobial activity of HBD3 was evaluated in a liquid microdilution assay.Results The fusion protein GST-HBD3 was efficiently cleaved by thrombin and yielded HBD3 that had anti-staphylococcus aureus activity with a minimal inhibitory concentration level of 12.5 μg/ml. The E. coli strain expressing the recombinant protein did not grow slower than the empty vector strain.Conclusion Active HBD3 in E. coli by expressing the recombinant protein GST-HBD3 could be produced, and suicide did not occur in the E. colistrain expressing the recombinant protein。

Abstract：Background The multidrug resistance (MDR) associated with the expression of the mdr1 gene and its product P-glycoprotein is a major factor in the prognosis of hepatocellular carcinoma cell (HCC) patients treated with chemotherapy. Our study was to establish a stable HCC MDR cell line where a de novo acquisition of multidrug resistance specifically related to overexpression of a transgenic mdr1.Methods The 4.5-kb mdr1 cDNA obtained from the plasmid pHaMDR1-1 was cloned into the PCI-neo mammalian expression vector, later was transferred by liposome to human hepatocarcinoma cell line HepG2. Then the transfected HepG2 cells resisting G418 were clustered and cultured and the specific fragment of mdr1 cDNA, mRNA and the P-glycoprotein (Pgp) in these HepG2 cells were detected by PCR, RT-PCR and flow cytometry, respectively. The accumulation of the daunorubicin was determinated by flow cytometry simultaneously. The nude mice model of grafting tumour was established by injecting subcutaneously HepG2/mdr1 cells in the right axilla. When the tumour diameter reached 5 mm, adriamycin was injected into peritoneal cavity. The size and growth inhibition of tumour were evaluated.Results The mdr1 expression vector was constructed successfully and the MDR HCC line HepG2/mdr1 developed.The PCR analysis showed that the specific fragment of mdr1 cDNA in HepG2/mdr1 cells, but not in the control group HepG2 cells. Furthermore, the content of the specific fragment of mdr1 mRNA and Pgp expression in HepG2/mdr1 cells were (59.7±7.9)% and (12.28±2.09)%, respectively, compared with (16.9±3.2)% and (3.07±1.06)% in HepG2 cells.In the nude mice HCC model, the tumour genes of both groups were identified. After ADM therapy, the mean size of HepG2 cell tumours was significantly smaller than HepG2/mdr1 cell tumours.Conclusion The approach using the transfer of mdr1 cDNA may be applicable to the development of MDR hepatocarcinoma cell line, whose MDR mechanism is known. This would provide the experimental basis of MDR research。

Abstract：Background Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. This study was designed to develop a tissue engineering heart valve by using human umbilical cord blood-derived endothelial progenitor cells (EPCs) and decellularized valve scaffolds.Methods Decellularized valve scaffolds were prepared from fresh porcine heart valves. EPCs were isolated from fresh human umbilical cord blood by density gradient centrifugation, cultured for 3 weeks in EGM-2-MV medium, by which time the resultant cell population became endothelial in nature, as assessed by immunofluorescent staining. EPC-derived endothelial cells were seeded onto the decellularized scaffold at 3 × 106 cells/cm2 and cultured under static conditions for 7 days. Proliferation of the seeded cells on the scaffolds was detected using the MTT assay. Tissue-engineered heart valves were analyzed by HE staining, immunofluorescent staining and scanning electron microscopy. The anti-thrombogenic function of the endothelium on the engineered heart valves was evaluated by platelet adhesion experiments and reverse transcription-polymerase chain reaction (RT-PCR) analysis for the expression of endothelial nitric oxide synthase (eNOS) and tissue-type plasminogen activator (t-PA).Results EPC-derived endothelial cells showed a histolytic cobblestone morphology, expressed specific markers of the endothelial cell lineage including von Willebrand factor (vWF) and CD31, bound a human endothelial cell-specific lectin,Ulex Europaeus agglutinin-1 (UEA-1), and took up Dil-labeled low density lipoprotein (Dil-Ac-LDL). After seeding on the decellularized scaffold, the cells showed excellent metabolic activity and proliferation. The cells formed confluent endothelial monolayers atop the decellularized matrix, as assessed by HE staining and immunostaining for vWF and CD31. Scanning electron microscopy demonstrated the occurrence of tight junctions between cells forming the confluent monolayer. Platelets adhesion experiments suggested that the neo-endothelium was non-thrombogenic. The expression levels of eNOS and t-PA genes in the neo-endothelium were quite similar to those in human umbilical vein endothelial cells.Conclusions EPCs isolated from the human umbilical cord blood can differentiate into endothelial cells in vitro and form a functional endothelium atop decellularized heart valve scaffolds. Thus, EPCs may be a promising cell source for constructing tissue-engineered heart valves。

Abstract：Background It is accepted that inflammatory cytokines play a key role in the development of acute pancreatitis, so blocking the initiation of inflammatory reactions may alleviate pathological changes of acute pancreatitis. We studied the regulatory effect of arsenic trioxide (As2O3) on apoptosis and oncosis of pancreatic acinar cells in vitro and in vivo and its therapeutic effect on acute pancreatitis.Methods Pancreatic acinar cells were isolated by collagenase digestion method. Apoptosis and oncosis of isolated pancreatic acinar cells were detected with Hoechst 33258+PI or Annexin V+PI double fluorescent staining. Amylase and lactate dehydrogenase release were measured. Acute pancreatitis was induced in Wistar rats by intraperitoneal injections of caerulein, and apoptosis was detected with terminal dUTP nick-end labeling method. Tumor necorsis factor α (TNF-α) mRNA, myeloperoxidase, nuclear factor-κB and histological grading of pancreatic damage were measured.Results There was an increased apoptosis but a decreased oncosis of pancreatic acinar cell after the treatment with As2O3. The levels of lactate dehydrogenase and amylase release were markedly decreased in As2O3 treated group.Myeloperoxidase content, TNF-α mRNA level, nuclear factor-κB activation and pathological score in As2O3 treated group were significantly lower than in the untreated group.Conclusions As2O3 can induce apoptosis and reduce oncosis of pancreatic acinar cell, thus resulting in reduced release of endocellular enzyme of acinar cells, reduced inflammatory cell infiltration and decreased the production of inflammatory cytokines, so that the outcome of alleviated pathological changes was finally achieved。

Abstract：Background Noise is widespread occupational hazard in iron and steel industry. Overhead-traveling cranes are widely used in this industry, but few studies characterized the overhead-traveling crane drivers' noise exposure level so far. In this study, we assessed and characterized personal noise exposure levels of overhead-traveling crane drivers in two steel-rolling mills.Methods One hundred and twenty-four overhead-traveling crane drivers, 76 in the cold steel-rolling mill and 48 in the hot steel-rolling mill, were enrolled in the study. Personal noise dosimeters (AIHUA Instruments Model AWA5610e,Hangzhou, China) were used to collect full-shift noise exposure data from all the participants. Crane drivers carried dosimeters with microphones placed near their collars during the work shifts. Work logs had been taken by the drivers simultaneously. Personal noise exposure data were divided into segments based on lines in which they worked. All statistical analyses were done using SPSS 13.0.Results The average personal noise exposure (LAeq.8h) of overhead-traveling crane drivers in the hot steel-rolling mills ((85.03±2.25) dB(A)) was higher than that in the cold one ((83.05±2.93) dB(A), P＜0.001). There were 17 overhead traveling cranes in the hot steel-rolling mill and 24 cranes in the cold one, of which carrying capacities varied from 15 tons to 100 tons. The average noise exposure level based on different lines in the hot and cold steel-rolling mills were (85.2±2.61) dB(A) and (83.3±3.10) dB(A) respectively (P=0.001), which were similar to the average personal noise exposure in both mills. The noise exposure levels were different among different lines (P=0.021).Conclusion Noise exposure levels, depending upon background noise levels and the noise levels on the ground, are inconstant. As the noise exposure levels are above the 85 dB(A) criteria, these drivers should be involved in the Hearing Conservation Program to protect their hearing。

Abstract：Background Vasoactive drugs are often necessary for reversing hypotension in patients with severe infection. The standard for evaluating effects of vasoactive drugs should not only be based on the increase of arterial blood pressure,but also on the blood flow perfusion of internal organs. The effects of dopamine and metaraminol on the renal function of the patients with septic shock were investigated retrospectively in this study.Methods Ninety-eight patients with septic shock were divided into three groups according to the highest infusing rate of metaraminol, with the lightest infusing rate of (0.1-0.5, 0.6-1.0, ＞1.0) μg · kg-1 · min-1 in group A, B and C respectively.Urine output, mean arterial blood pressure (MAP), heart rate (HR), urine output, blood urea nitrogen (BUN), creatinine (CRE), urine albumin (U-ALB), urine β2-microglubulin (Uβ2-MG) and Apache Ⅲ scores were recorded.Results Before antishock therapy, hypotension, tachycardia and oliguria occurred to all the 98 patients with septic shock and CRE, BUN, U-ALB, Uβ2-MG and Apache Ⅲ scoring were abnormal in most cases. With the antishock therapy,MAP, HR, urine output, BUN and CRE in all patients returned gradually to normal (P＜0.05 or ＜0.01 compared to those before antishock therapy). U-ALB, Uβ2-MG output and Apache Ⅲ scoring also reverted but remained abnormal (P＜0.01 compared to those before antishock therapy). No statistically significant differences in the changes of these indices with the time existed among the three groups (P＞0.05).Conclusion Dopamine and metaraminol when applied to the patients with septic shock could effectively maintain the circulatory stability and promote restoration of renal function。

Abstract：Background Anterior mediastinal masses include a wide variety of diseases from benign lesions to extremely malignant tumors. Management strategies are highly diverse and depend strongly on the histological diagnosis as well as the extent of the disease. We reported a prospective study comparing the usefulness of core needle biopsy and mini-mediastinotomy under local anesthesia for histological diagnosis in anterior mediastinal masses.Methods A total of 40 patients with masses of unknown histology and located either at or near the anterior mediastinum received biopsy prior to treatment. The diagnostic methods were core needle biopsy in 28 patients and biopsy through mini-mediastinotomy under local anesthesia in 15 patients (including 3 patients for whom core needle biopsy failed to yield a definite diagnosis).Results Histological diagnosis was achieved in 18 of the 28 patients receiving core needle biopsy. Of them, all 4 patients with pleural fibromas and 9 of the 12 patients (75%) with pulmonary mass were diagnosed definitively. In the remaining 12 patients with mediastinal mass, histological diagnosis was achieved in only 5 patients (41.7%). In contrast,biopsy through a mini-mediastinotomy failed in only 3 patients. In the remaining 12 patients with huge mediastinal masses, who underwent mini-mediastinotomy, a definitive histological diagnosis was reached by pathological and/or immunohistochemical study (diagnostic yield 85.7% in 12 of 14 cases of mediastinal mass, P=0.038 vs core needle biopsy). For the 9 patients with thymic epithelial tumors, the diagnostic yield was 40% (2 in 5 cases) for core needle biopsy and 83.3% (5 in 6 cases) for mini-mediastinotomy. There was no morbidity in patients receiving mini-mediastinotomy. In the 30 patients with biopsy-proven histological diagnosis, the results contributed to therapeutic decision making in 25 cases (83.3%).Conclusions Core needle biopsy is effective in the diagnosis of pulmonary and pleural diseases. Yet its diagnostic yield in mediastinal mass is rather low. Superior to core needle biopsy, biopsy through a mini-mediastinotomy under local anesthesia is highly effective in the histological diagnosis of anterior mediastinal mass, and has a satisfactory diagnostic yield. The method is safe, minimally invasive, cost-effective, and useful in therapeutic decision making for anterior mediastinal masses。

Abstract：Background The effect of chronic stress on cognitive functions has been one of the hot topics in neuroscience. But there has been much controversy over its mechanism. The aim of this study was to investigate the effects of chronic multiple stress on spatial learning and memory as well as the expression of Fyn, BDNF and TrkB in the hippocampus of rats.Methods Adult rats were randomly divided into control and chronic multiple stressed groups. Rats in the multiple stressed group were irregularly and alternatively exposed to situations of vertical revolution, sleep expropriation and restraint lasting for 6 weeks, 6 hours per day with night illumination for 6 weeks. Before and after the period of chronic multiple stresses, the performance of spatial learning and memory of all rats was measured using the Morris Water Maze (MWM). The expression of Fyn, BDNF and TrkB proteins in the hippocampus was assayed by Western blotting and immunohistochemical methods. The levels of Fyn and TrkB mRNAs in the hippocampus of rats were detected by RT-PCR technique.Results The escape latency in the control group and the stressed group were 15.63 and 8.27 seconds respectively.The performance of spatial learning and memory of rats was increased in chronic multiple stressed group (P＜0.05). The levels of Fyn, BDNF and TrkB proteins in the stressed group were higher than those of the control group (P＜0.05). The results of immunoreactivity showed that Fyn was present in the CA3 region of the hippocampus and BDNF positive particles were distributed in the nuclei of CA1 and CA3 pyramidal cells as well as DG granular cells. Quantitative analysis indicated that level of Fyn mRNA was also upregulated in the hippocampus of the stressed group (P＜0.05).Conclusions Chronic multiple stress can enhance spatial learning and memory function of rats. The expression of Fyn,BDNF and TrkB proteins and the level of Fyn mRNA are increased in the stessed rat hippocampus. These suggest that Fyn and BDNF/TrkB signal transduction pathways may participate in the process of the enhanced learning and memory during chronic multiple stress。

Abstract：Background Seprase plays an important role in malignant cell invasion and metastasis by degrading the extracellular matrix. Hcwever, its clinical significance remains largely unknown. The objective of the current study was to evaluate the expression of seprase in effusions from patients with epithelial ovarian carcinoma and its clinical values.Methods Immunohistochemistry was used to examine the expression of seprase protein in a series of 74 malignant peritoneal (n=64) and pleural (n=10) effusions from Norwegian patients with epithelial ovarian carcinoma. Additionally, 34 effusions were evaluated using the Western blotting. Nine reactive effusions, obtained from patients with benign lesions,served as a control group. Statistical analyses were carried out by Chi-square test and Kaplan-Meier method.Results In the 74 malignant effusion specimens, 57 (77.02%) were positive for seprase, while only 2 (22.22%) of the control group were positively stained (P=0.001). In the malignant effusions, 17 (22.97%), 22 (29.73%), 22 (29.73%), 13 (17.57%) had negative, weak, moderate and strong seprase protein expression, respectively. The expression of seprase protein was predominant in cytoplasm of carcinoma cells. Increased seprase protein was negatively associated with the overall survival rate of the patients (P=0.03). However, there was no significant correlation between protein expression and FIGO stage, age, histology, and histological grade. By Western blotting, 27 of the 34 effusions showed the presence of both 170-kD dimeric form and 97-KD monomeric form of seprase while only 1 of the 34 had 170-KD dimeric form,which was consistent with the results of immunohistochemistry (P=0.05).Conclusions Seprase may be involved in the development of ovarian cancer, and is a potential predictive marker for the disease。

Voltage-gated sodium channels play an important role in the generation and propagation of action potentials in excitable cells. They are composed of a pore-forming α subunit and auxiliary β subunits. To date,nine subtypes of the α subunit, designated Nav 1.1 to Nav1.9, have been shown to form functional sodium channels。

Severe acute respiratory syndrome (SARS) is a life threatening, upper respiratory disease. Its cause is a coronavirus, SARS-CoV. Since its emergence in 2003 in China, SARS has affected more than 8000 patients and caused 776 deaths in 26 countries.1 A reemergence of SARS occurred in Guangdong province, in which the first case was confirmed on January 5, 2004 and three more reported the following month。

The prevalence of myocardial bridging in hypertrophic cardiomyopathy (HCM) is relatively higher, and it usually occurs in the middle and distal portions of the left anterior descending artery。

Blue rubber bleb nevus syndrome (BRBNS), or Bean's syndrome, is a rare angiomatosis characterized by distinctive cutaneous and gastrointestinal venous malformations that usually cause massive or occult gastrointestinal hemorrhage and iron deficiency anemia secondary to the bleeding episodes。

Epithelioid trophoblastic tumor(ETT)of the uterus is a rare tumor introduced recently,which is distinct from placental site trophoblastic tumor (PSTT) and choriocarcinoma with the histological appearance of resembling low-grade squamous cell carcinomas。

Although meningiomas are common tumors in adults,the chordoid variant is very rare. According to the World Health Organization Classification of Tumors of the Nervous System (Lyon, 2000),1 chordoid meningioma together with another rare variant, lymphoplasmacyterich meningioma, usually contain abundant lymphoplasmacytic infiltration, and are associated even with hematological abnormalities, especially in young adults。

A nnular pancreas is a congenital anomaly which consists of a ring of pancreatic tissue partially or completely encircling the descending portion of theduodenum. It was first described by Tiedemann1 in 1818 and named "annular pancreas" by Ecker2,3 in 1862。