Humans ; Lung Neoplasms ; chemically induced ; Proportional Hazards Models ; Radon ; adverse effects

Circadian rhythms describe biological phenomena that oscillate with an 24 hour cycle. These rhythms include blood pressure, body temperature, hormone level, the number of immune cells in blood, and the sleep-wake cycle. The aim is to introduce common genes between species that are responsible for determining the circadian behavior, especially some transcription factor s that serve to regulate many circadian rhythm genes. And the common molecular mechanism of biological clocks between fly and human will be in troduced.

Bone marrow stromal cells(MSCs) have been shown to be extremely versatile.Recently,it is demonstrated that MSCs differentiate into neurons.Moreover,under the appropriate conditions,MSCs differentiate into special phynotype of neurons,such as 5-hydroxytryptamine-sensitive neurons,and dopaminergic neurons.The mechanism remains to be elucidated,and an overexpression of neuronal specific genes(such as Sox,Pax,Notch gene) may play an important role,especially RB/PBO gene.However,RB triggers cholinergic differentiation.Extrinsic factor such as concentration of cAMP plays certain role in differentiation.MSCs have also been shown to have certain therapeutic effect on neuronal degeneration disease.These cells have great potential because it is easy to isolate,culture,amplify,and no ethics neither immunologic rejection problem was concerned.

The goal of graduate students'cultivation is training talented persons with creativity.Academic forum plays an important role in graduate students' cultivation,which can stir up graduate students'creative thought and bring an atmosphere of studying hard.

Background and purpose:The lymph node metastatic model of rectal tumor is a useful tool for the research on tumor occurrence, development, metastasis and antineoplastic therapy. There are few reports about establishment of larger animal model. This study aimed to establish feasible and reproducible lymph node metastatic models of VX2 tumor in rabbits.Methods:The VX2 tumor tissue was put into the puncture needle. The VX2 tumor tissue in the needle was orthotopically transplanted into the rectal wall of the New Zealand white rabbits successfully. Twenty New Zealand white rabbits were transplanted. Two experimental rabbits were scanned by MR weekly. Tumor growth curve and lymph node numbers were observed on MR. Experimental rabbit tumor volumes were measured by MR post-processing software. The rectal tumor and surrounding lymph nodes were resected, and the specimens were ifxed. The sections were stained with HE. We explored the relationship between tumor volume and growth time, the number of metastatic lymph nodes and tumor volume, respectively.Results:Thirteen models were successfully established with a rate of 65%. Tumors limited in the rectal wall were observed on the fourth week. Tumor size increased over time. There was significant difference in the tumor volume between different periods (growth cycle number) (F=52.865,P<0.05). There was a signiifcantly positive correlation between tumor volume and the growth cycle number (r=0.910,P<0.05). The metastatic lymph nodes could be observed when VT>9 cm3. The number of metastatic lymph node increased obviously from the ninth week. The more tumor volume, the greater the number of metastatic lymph nodes was observed (F=92.531,P<0.05). There was a signiifcantly positive correlation between the number of metastatic lymph nodes and the tumor volume (r=0.945,P<0.05).Conclusion:Metastatic lymph node models of VX2 tumor in New Zealand white rabbits were established successfully. This model has some value in the research on local growth, invasion mechanism, lymph node metastasis and biological characteristics of rectal cancer.

Air ; analysis ; Chromatography, Gas ; methods ; Methylene Chloride ; analysis ; Workplace

Objective To investigate the impact of gantry angles on the position accuracy of buildin multi-leaf collimator (MLC) during static (step & shoot) intensity modulated radiotherapy (IMRT).Methods The position accuracy of MillenniumTM 60 pairs multi-leaf collimator (MLC) in Varian 23EX medical linear accelerator during 10 fractions of treatments with static intensity modulated radiotherapy (IMRT) was retrospectively analyzed by resolving dynamic therapy log files and MLC planning files.The single leaf position deviation and gap deviation of each MLC pairs were compared between expected values and actual outcomes.The impact of gantry angle on MLC position accuracy was also investigated with paired t-test between vertical and horizontal beams.Results All the MLC position deviations ranged within ± 1.0 mm,while the gap deviations were at the range of ± 1.5 mm.The statistical standard deviation of MLC position deviations among fractions was less than 0.06 mm.After all the 60 pairs of MLC leaves were taken into account,the M LC position deviation in the field of 103° was smaller than in the field of 0° (t =58.74,P ＜ 0.01),but there was no significant difference between 257° and 0°,while only the moving leaves were put into consideration,the MLC position deviation in the field of 103° was still smaller than in the field of 0°,but the MLC position deviation in the field of 257° was slightly higher than in thefield of 0° (t =41.95、-4.47,P ＜ 0.01).Conclusions The MillenniumTM 60 pairs MLC in Varian 23EX medical linear accelerator meets the mechanical quality assurance requirement during static IMRT treatments.The MLC positioning showed stable repeatability among treatment fractions.Although the MLC position accuracy is slightly affected by gravity from different gantry angles,but still meets the mechanical QA requirements for medical linear accelerator.This dynamic analysis method is expected to be a novel strategy which may improve the existing QA protocols.

BACKGROUND: Cigarette smoking has been recognized as one of the high risk factors in carcinogenesis of lung cancer. Early diagnosis of lung cancer may be of clinical therapy value.OBJECTIVE: To explore the mutation of K-ras oncogene in bronchoalveolar lavage fluid(BALF) in order to reveal its relationship with cigarette smoking in lung cancer patients.DESIGN: Randomized controlled trial based on the patients.SETTING: Department of Toxicology, College of Radiology and Public Health of a university, and Department of Respiratory Medicine of a university hospital.PARTICIPANTS: The out-patients and inpatients in the Second Affiliated Hospital of Soochow University between June 1999 and September 2001 were included. The patients were confirmed to have lung cancer or innocuous diseases by fiber bronchoscopy through bronchoalveolar lavage(BAL) and cytological or pathological examination.METHODS: BALF samples were obtained from 37 smoking patients with lung cancer and 25 nonsmoking patients with lung cancer, and 20 with benign pulmonary diseases in the Second Affiliated Hospital of Soochow University. They were detected for K-ras codon 12 mutations using polymerase chain reaction with restriction fragment length polymorphism(PCR-RFLP).MAIN OUTCOME MEASURES: Codon 12 mutations of K-ras gene.RESULTS: K-ras mutation in patients with lung cancer was found to have an average frequency of 36% (22/62)but no K-ras gene mutation was detected in patients with benign pulmonary diseases. The mutation frequency in heavy smokers(69% ) was higher than that in moderate smokers(31%), mild smokers (25%) and nonsmokers (20%). The mutation was related to age and history of smoking, but not to sex and TNM classification.CONCLUSION: Cigarette smoking may be correlated with the mutation of K-ras gene. Early detection of K-ras mutation in BALF may be of clinical value, which helps the identification and diagnosis of smoking-related lung cancer.

Objective To discuss the applied value of multislice spiral CT(MSCT) in diagnosing and localizing the embedded supernumerary teeth. Methods A total of 43 cases with the embedded supernumerary teeth were undergone MSCT using shaded surface display(SSD), minimum intensity projection(MIP) and multiplanar reformation(MPR) to present the form and location of the embedded supernumerary teeth and to determine the surgical style.The result of image was retrospectively analysed after operation.Results The reconstruction images,could clearly show the dental surface image including crown, root, neck and root bifurcation, labial or palatal location, eruption orientation and relation with dentition in anterior maxilla. The position of 52 embedded supernumerary teeth in 43 patients were completely confirmed by surgery with accuracy of 100%. All patients were well healed with no infection and injury to nearby teeth. Conclusion The Embedded supernumerary teeth in bone can be detected by MSCT and MSCT can be used as an important examination technique before surgical and orthodontic treatment.

In the rabbit's myocardial sarcolemma and artificial biomem-brane-liposomes, the lipid peroxidation caused by free radical gene-arting system ( FeCls & ascorbic acid ) was significantly inhibited by taurine at the concentractions of 5~20 m mol/L, and the inhibition effects of taurine were both dose and time-dependent. The results showed that taurine had an antioxidation effects and served as a scavenger of free radicals at the level of membrane.