医古文双语教学的思路及实践体会

结合教学实践体会,探讨了医古文双语教学的性质和目的,阐述了医古文双语教学中外语辅助教学的主要内容及其作用,说明了对新的教学模式的探索和目前尚存在的不足,指出了在新时期开设医古文双语教学的积极意义。     

Waiting for radiation therapy: Does it matter?

The aim of this study was to determine the direct and indirect effects of prolonged waiting times for radiation therapy. We used the Medline, CancerNet and EMBASE databases to search the international research using the keywords radiotherapy, waiting times and delay. The negative effects of prolonged waiting times for radiation therapy can be broken down into direct and indirect effects. Direct effects include tumour control factors and patient factors. Indirect effects include changes in referral patterns and change in management of tumours. The precise effects of prolonged waiting times for radiation therapy are difficult to define. Evidence exists for some tumour sites, such as postoperative head and neck, small‐cell lung cancer and high‐grade cerebral gliomas, that tumour control might be adversely affected. The effect on other tumour sites is less established. Patient factors are likely to be consistent across all tumour types and indirect effects are hard to quantify.     

Adenoviral Vector-mediated Gene Transfer: Timing of Wild-type P53 Gene Expression in vivo and Effect of Tumor Transduction on Survival in a Rat Glioma Brachytherapy Model

Objective. This study sought to investigate modification of the radiation response in a rat 9L brain tumor model in vivo by the wild-type p53 gene (wtp53). Determination of the timing and dose of radiation therapy required the assessment of the duration of the effect of wtp53 expression on 9L tumors after in vivo transfection. Methods. Anesthetized male F-344 rats each were stereotactically inoculated with 4 × 10⁴ 9L gliosarcoma cells through a skull screw into the cerebrum in the right frontal region. Twelve-day-old tumors were inoculated through the screw with recombinant adenoviral vectors under isoflurane anaesthesia: control rats with Ad5/RSV/GL2 (carrying the luciferase gene), and study rats with Ad5CMV-p53 (carrying the wtp53 gene). Brain tumors removed at specific times after transfection were measured, homogenized, and lysed and wtp53 expression determined by Western blot analysis. Four groups of nine rats were, subsequently, implanted with iodine-125 seeds 15 days post-tumor inoculation to give a minimum tumor dose of 40 or 60Gy. Results. We demonstrated transfer of wtp53 into rat 9L tumors in vivo using the Ad5CMV-p53 vector. The expression of wtp53 was demonstrated to be maximum between days 1 and 3 post-vector inoculation. Tumors expressing wtp53 were smaller than controls transfected with Ad5/RSV/GL2 but this difference was not statistically significant. Radiation made a significant difference to the survival of tumor-bearing rats. Moreover, wtp53 expression conferred a significant additional survival advantage. Conclusion. The expression of wtp53 significantly improves the survival of irradiated tumor-bearing rats in our model.     

The control of interresponse time probabilities by the magnitude of reinforcing brain stimulation

To assess the relation between the probability of individual interresponse times (IRTs) and the magnitude of contingent reinforcing brain stimulation, a schedule was used which restricts reinforcer presentation to responses spaced by a minimum temporal interval. The probability of IRTs falling in the region of the criterion interval increased monotonically with current amplitude across a wide range of scheduled intervals. These results contrast with IRT performance under continuous and variable-interval schedules, where a wide variety of idiosyncratic functional relations has been found. Use of the IRT schedule thus helps to clarify the function of brain stimulation magnitude in free-operant responding, providing an alternative datum to potentially confounded average response rate measures. The scheduled spacing of responses also allows an analysis in terms of the discrimination of temporal intervals. As brain stimulation magnitude increased, IRT distributions showed more discrete peaking near the criterion interval, and thus finer temporal discrimination. IRTs following a reinforced response were paced more accurately than IRTs following a nonreinforced response, pointing to the discriminative function of reinforcer presentation (proportional to brain stimulation magnitude) in temporal discrimination procedures. A signal detection analysis indicated that an animal's bias toward emission of subcriterion IRTs increases along with temporal discrimination accuracy in proportion to brain stimulation magnitude.     

A Finite Volume Method for Modeling Discontinuous Electrical Activation in Cardiac Tissue

This paper describes a finite volume method for modeling electrical activation in a sample of cardiac tissue using the bidomain equations. Microstructural features to the level of cleavage planes between sheets of myocardial fibers in the tissue are explicitly represented. The key features of this implementation compared to previous modeling are that it represents physical discontinuities without the implicit removal of intracellular volume and it generates linear systems of equations that are computationally efficient to construct and solve. Results obtained using this method highlight how the understanding of discontinuous activation in cardiac tissue can form a basis for better understanding defibrillation processes and experimental recordings.     

Does Conversion of a Laparoscopic Colectomy Adversely Affect Patient Outcome?

PURPOSE Conversion during laparoscopic colectomy varies in frequency according to the surgeons experience and case selection. However, there remains concern that conversion is associated with increased morbidity and higher hospital costs.METHODS From January 1999 to August 2002, 430 laparoscopic colectomies were performed by two surgeons, with 51 (12 percent) cases converted to open surgery. Converted cases were matched for operation and age to 51 open cases performed mostly by other colorectal surgeons from our department. Data collected included gender, American Society of Anesthesiology score, operative indication, resection type, operative stage at conversion, in-hospital complications, direct hospital costs, unexpected readmission within 30 days, and mortality.RESULTS There were no significant differences between the groups for age (converted, 55 ± 19; open, 62 ± 16), male:female ratio (converted, 17:34; open, 23:28), or American Society of Anesthesiology score distribution. Indications for surgery were neoplasia (converted, 16; open, 31); diverticular disease (converted, 21; open, 13); Crohns disease (converted, 12; open, 5); and other disease (converted, 2; open, 2). Operative times were similar (converted, 150 ± 56 minutes; open, 132 ± 48 minutes). Conversions occurred before defining the major vascular pedicle/ureter (50 percent), in relation to intracorporeal vascular ligation (15 percent), or during bowel transection or presacral dissection (35 percent). Specific indications for conversion were technical (41 percent), followed by adhesions (33 percent), phlegmon or abscess (23 percent), bleeding (6 percent), and failure to identify the ureter (6 percent). Median hospital stay was five days for both groups. In-hospital complications (converted 11.6 percent; open 8 percent), 30-day readmission rate (converted 13 percent vs. open 8 percent), and direct costs were similar between groups. There were no mortalities.CONCLUSION Conversion of a laparoscopic colectomy does not result in inappropriately prolonged operative times, increased morbidity or length of stay, increased direct costs, or unexpected readmissions compared with similarly complex laparotomies. A policy of commencing most cases suitable for a laparoscopic approach laparoscopically offers patients the benefits of a laparoscopic colectomy without adversely affecting perioperative risks.Read at the meeting of The American Society of Colon and Rectal Surgeons, New Orleans, Louisiana, June 21 to 26, 2003.     

Quantitative apparent diffusion coefficients and T2 relaxation times in characterizing contrast enhancing brain tumors and regions of peritumoral edema

PURPOSE: To investigate the potential value and relationship of in vivo quantification of apparent diffusion coefficients (ADCs) and T2 relaxation times for characterizing brain tumor cellularity and tumor-related edema. MATERIALS AND METHODS: A total of 26 patients with newly diagnosed gliomas, meningiomas, or metastases underwent diffusion-weighted and six-echo multisection T2-preparation imaging. Regions of interest (ROIs) were drawn on conventional MR images to include tumor (as defined by contrast agent enhancement) and immediate and peripheral edema. Areas of necrosis were excluded. Median values of ADCs and T2 in the ROIs were calculated. RESULTS: ADCs for gliomas were similar to those for meningiomas or metastases in all regions. Tumor T2 values for gliomas (159.5+/-30.6 msec) were significantly higher than those for meningiomas or metastases (125.0+/-31.1 msec; P=0.005). Immediate-edema T2 values for meningiomas or metastases (226.0+/-44.1 msec) were significantly higher than those for gliomas (203.5+/-32.8 msec; P=0.033). Peripheral-edema T2 values for gliomas (219.5+/-41.9 msec) were similar to those for meningiomas or metastases (202.5+/-26.5 msec; P=0.377). Both immediate- and peritumoral-edema ADCs and T2 values were significantly higher than those in tumor for both tumor types. ADCs and T2 values from all regions correlated significantly for gliomas (r=0.95; P<0.0001) and for meningiomas or metastases (r=0.81; P<0.0001). CONCLUSION: The higher immediate-edema T2 values for nonglial tumors than for gliomas suggest tumor-related edema (vasogenic vs. infiltrated) can be further characterized by using T2 values. There were significant correlations between ADC and T2 values.     

Plasma volume in normal pregnant Nigerian primigravidae

Plasma volume was measured in 10 non-pregnant, healthy nulliparous Nigerian and 30 normal primigravid Nigerians at various times of gestation by the Evans blue dye dilution technique. The mean plasma volume of 2098 ml for the non-pregnant Nigerians was statistically different (P less than 0.001) from values in non-pregnant caucasian primigravidae of comparable status. A mean maximum plasma volume increase of 1387 ml above non-pregnant value was found. Essentially, pregnancy imposed a much higher physiological load on Nigerian primigravidae compared to caucasian primigravidae. There was a significant negative correlation between plasma volume and packed cell volume (PCV) in pregnancy (r = -0.51, P less than 0.001), which may be related to excessive hemodilution in the primigravid Nigerian. Differences found may be due to geographical and/or racial factors.     

二次分冠"抽屉"式拔除水平阻生齿临床效果评价

目的观察采用二次分冠“抽屉”式拔除法拔除阻生齿的临床效果。方法观察实验组60只阻生齿用二次分冠法拔除效果,与对照组60只阻生齿常规翻瓣法拔除比较。结果二次分冠法拔除阻生齿成功率为95%。实验组手术时间明显比对照组手术时间短(P<0.05)。两组患者局部肿胀、疼痛和张口受限程度存在显著性差异(P<0.05)。结论采用二次分冠法拔除阻生齿,手术简便,时间短,术后不良反应少。