青少年和成年人无症状阻生智齿干预措施的疗效评价

目的评价在青少年和成人中拔除与保留无症状阻生智齿的效果.方法计算机检索Cochrane口腔健康组资料库(至2004年8月4日),Cochrane中心临床对照试验资料库(CENTRAL),Ovid-MEDLINE(1966～2004年8月4日),PubMed(1966～2004年8月4日)和EMBASE(1974～2004年8月4日).检索无语种限制.同时对主要相关杂志进行手检,并尽力获取正在进行和未发表的研究.纳入比较预防性拔除与保留阻生智齿效果的全部随机对照或临床对照研究.由3位作者分别独立评价所检出文献的相关性、真实性并提取数据,如有不确定性,联系作者以获取关于随机和失访的更多信息.对所有试验均进行了质量评价.结果共纳入3个研究,其中2个已完成的随机对照试验评价了青少年预防性拔除智齿对切牙拥挤的影响,另1个随机对照试验正在进行,但研究者不能提供任何资料,他们准备近期发表文章,如是,其资料将被纳入本评价的更新中.已完成的2个研究结局判断指标不同,不能进行数据合并.结论没有证据支持或反对常规预防性拔除成年人无症状阻生智齿,有一些可靠的证据表明在青少年预防性拔除阻生智齿既不能减少也不能预防切牙拥挤.     

Thrombin generation during cardiopulmonary bypass: the possible role of retransfusion of blood aspirated from the surgical field

BACKGROUND: In spite of using heparin-coated extracorporeal circuits, cardiopulmonary bypass (CPB) is still associated with an extensive thrombin generation, which is only partially suppressed by the use of high dosages of heparin. Recent studies have focused on the origins of this thrombotic stimulus and the possible role of retransfused suctioned blood from the thoracic cavities on the activation of the extrinsic coagulation pathway. The present study was designed to find during CPB an association between retransfusion of suctioned blood from the pericardium and pleural space, containing activated factor VIIa and systemic thrombin generation. METHODS: Blood samples taken from 12 consenting patients who had elective cardiac surgery were assayed for plasma factor VIIa, prothrombin fragment 1+2 (F1+2), and thrombin-antithrombin (TAT) concentrations. Blood aspirated from the pericardium and pleural space was collected separately, assayed for F1+2, TAT, and factor VIIa and retransfused to the patient after the aorta occlusion. RESULTS: After systemic heparinization and during CPB thrombin generation was minimal, as indicated by the lower than base line plasma levels of F1+2, and TAT after correction for hemodilution. In contrast, blood aspirated from the thoracic cavities had significantly higher levels of factor VIIa, F1+2, and TAT compared to the simultaneous samples from the blood circulation (P < 0.05). Furthermore, after retransfusion of the suctioned blood (range, 200-1600 mL) circulating levels of F1+2, and TAT rose significantly from 1.6 to 2.9 nmol/L (P = 0.002) and from 5.1 to 37.5 μg/L (P = 0.01), respectively. The increase in both F1+2, and TAT levels correlated significantly with the amount of retransfused suctioned blood (r = 0.68, P = 0.021 and r = 0.90, P = 0.001, respectively). However, the circulating factor VIIa levels did not correlate with TAT and F1+2 levels. CONCLUSIONS: These data suggest that blood aspirated from the thoracic cavities during CPB is highly thrombogenic. Retransfusion of this blood may, therefore, promote further systemic thrombin generation during CPB.     

Investigation of bladder dose and volume factors influencing late urinary toxicity after external beam radiotherapy for prostate cancer

BACKGROUND: We sought to identify the bladder dose-volume factors associated with an increased risk of late urinary toxicity among prostate cancer patients treated with radiotherapy. METHODS AND MATERIALS: This retrospective analysis included data from 128 prostate cancer patients treated on protocol with 2 Gy/fraction to 46 Gy followed by a boost to 78 Gy. The endpoint for this analysis was Grade 1 or greater late genitourinary (GU) toxicity occurring within two years of treatment. The Lyman-Kutcher-Burman, mean dose, threshold dose, and hottest volume models were fitted to the toxicity data using the maximum likelihood method. RESULTS: Model fits based on dose-volume histograms tended to fit the toxicity data better than models based on dose-wall histograms. The hottest volume (hotspot) model was found to be the best-fitting model investigated. The best fit was for the hottest 2.9% of bladder (95% CI, 1.1-6.8%). This model has an area under the receiver operating characteristic curve of 0.74. The hotspot model separated the patients into clinically meaningful subgroups with approximately 25% of the patients who received <78 Gy to the hottest 2.9% of bladder had GU toxicity at eight years compared with approximately 50% when the dose was > or =78 Gy (p = 0.002). CONCLUSION: This provides the first evidence supporting that bladder "hotspots" are related to GU toxicity within two years after external beam radiotherapy for prostate cancer. Confirming data are needed from other investigators. Particular attention should be given to hotspots higher than 78 Gy in bladder in radiation treatment planning.     

The ratio of positive to excised nodes identifies high-risk subsets and reduces inter-institutional differences in locoregional recurrence risk estimates in breast cancer patients with 1-3 positive nodes: an analysis of prospective data from British Columbia and the M. D. Anderson Cancer Center

PURPOSE: To examine the power of the nodal ratio (NR) of positive/excised nodes in predicting postmastectomy locoregional recurrence (LRR) in patients with 1-3 positive nodes (N+) and in identifying cohorts at similar risk across independent data sets. METHODS AND MATERIALS: Data from 82 patients with 1-3 N+ treated without postmastectomy radiotherapy (PMRT) in the British Columbia (BC) randomized trial were compared with data from 462 patients treated without PMRT in prospective chemotherapy trials at the M. D. Anderson Cancer Center (MDACC). Kaplan-Meier LRR curves were compared between centers using the absolute number of N+ and nodal ratios. RESULTS: The median number of excised nodes was 10 in BC and 16 in MDACC (p < 0.001). Examining LRR by number of N+, the 10-year LRR rate for patients with 1-3 N+ was higher in BC compared with MDACC (21.5% vs. 12.6%; p = 0.02). However, when examining LRR using NR, no differences were found between institutions. In patients with NR < or = 0.20, the 10-year LRR rate was 17.7% BC vs. 10.9% MDACC (p = 0.27). In patients with NR > or = 0.20, the 10-year LRR rate was 28.7% BC vs. 22.7% MDACC (p = 0.32). On Cox regression analysis, NR was a stronger prognostic factor compared with number of N +. CONCLUSIONS: In patients with 1-3 N+, evaluating nodal positivity using NR reduced inter-institutional differences in LRR estimates that may exist due to variations in numbers of nodes excised. Nodal ratio >0.20 was associated with LRR >20%, warranting PMRT consideration. Nodal ratio may be useful for extrapolating data from prospective trials to clinical practices in which axillary staging extent vary.     

Does variation in the in vitro cellular radiosensitivity explain the shallow clinical dose-control curve for malignant melanoma?

In radiotherapy, clinical dose-control curves are generally more shallow than what should be expected from in vitro dose-survival curves for human cells of the same histology. One possible explanation is that a considerable inter-tumor heterogeneity in radiosensitivity flattens out the presumably steep individual dose-control curves. This paper compares dose-control curves for malignant melanomas derived from clinical data with curves derived from in vitro cell-survival experiments. Although inter-tumour variability in the in vitro dose and fractionation sensitivity may explain parts of the discrepancy between the steepness of clinical and in vitro dose-control curves, the present calculation indicates that a considerable additional variability, undetected by current in vitro assays, must be assumed to exist in order to resolve the discrepancy.     

Fractionation sensitivity and immunological status in radiation treated murine sarcomas

The fractionation sensitivity of a strongly immunogenic murine fibrosarcoma (FSa1) was tested in highly immunosuppressed (18 Gy whole body irradiation, 10 fractions, 4 days and bone marrow salvage) and control mice (C3Hf/Sed). Radiation was delivered to extremity-transplanted tumors after reaching a volume of 250 mm3. Two, 4 and 10 fractions were used, delivering the radiation treatments to uniformly hypoxic tumors (by extremity clamping). Doses needed to attain a 10 day tumor-growth delay (TGD) over the volume range 250 mm3 to 1000 mm3, and doses necessary to reach a tumor-control probability of 50% (TCD50), were calculated for the three fractionation schedules. Immunosuppression influenced the TCD50 values profoundly: 56.2, 71.5, and 101.4 Gy in control mice versus 76.6, 104.2, and 141.1 Gy in immunosuppressed mice for 2, 4, and 10 fractions, respectively. The alpha/beta ratios estimated by reciprocal-dose analysis using the TGD and TCD50 assays were not significantly different, nor were the alpha/beta ratios of tumors grown in immunosuppressed mice (TGD 5.7 Gy; TCD50 5.3 Gy) as compared with tumors in control recipients (TGD 3.5 Gy; TCD50 4.9 Gy). In addition, direct analysis was used with the fractionated TCD50 data from control and immunosuppressed animals to calculate a immunity-related-cell-kill factor. For 250 mm3 tumors a 1.29 [0.99 . . . 1.59, 95% confidence interval] log10-kill factor was obtained.     

Electrophysiological effects of adenosine in the transplanted human heart. Evidence of supersensitivity

After cardiac transplantation, the denervated donor atria and ventricles demonstrate increased sensitivity to infusions of sympathomimetic amines. Recently, supersensitivity of the canine sinus and atrioventricular (AV) nodes to acetylcholine has also been demonstrated after parasympathetic denervation. Acetylcholine and the endogenous nucleoside adenosine exert similar electrophysiological effects in both the sinus and AV nodes, and share a common transduction process. We, therefore, hypothesized that after orthotopic cardiac transplantation, the donor (denervated) sinus node would demonstrate greater sensitivity to exogenous adenosine than the recipient (innervated) sinus node. The effects of incremental doses of intravenous adenosine (37-112 micrograms/kg) on changes in sinus cycle length (SCL) (delta SCLmax%), changes in PR interval (delta PRmax%), time to peak effect (sec), and duration of electrophysiological effects (sec) were prospectively measured in 28 orthotopic cardiac transplant patients and nine control subjects. The baseline SCL was 795 +/- 71 msec for the control subjects, 891 +/- 43 msec for the recipient atria, and 700 +/- 18 msec for the donor atria (p less than 0.05, donor vs. recipient). The delta SCLmax% for each dose of adenosine was similar in the innervated control and recipient atria. In contrast, the donor sinus node demonstrated a threefold to fourfold increased response to adenosine as compared with the recipient sinus node and a threefold to sixfold increased response as compared with control subjects. Similarly, the donor AV node demonstrated a threefold to fivefold increase in PR interval as compared with control subjects. The duration of sinus node slowing in the denervated atria was threefold to fivefold longer than in the recipient and control atria (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Major Neurological Disease and Occupational Exposure to Organic Solvents

Five patients are described who presented with major organicbrain disease affecting one or more of pyramidal and extrapyramidaltracts, cerebellum, and higher cortical functions. All had ahistory of 10 years or more of regular occupational exposureto solvents in confined spaces, three in painting inside shipsand the others in weapons maintenance and printing. All hadbeen regularly exposed to high air vapour peaks as well as toskin contamination. Four showed some evidence of improvementafter the exposure ceased. None was initially suspected of havinga toxic encephalopathy by the consultant to whom he was referred.The spectrum of neurological disease presented by these menmirrors closely that described in solvent abusers. All wereforced by illness to retire from their work, a circumstancewhich might have in the past have led to such conditions beingmissed in cross-sectional studies, which in general have notshown evidence of major disease. We suggest that when such diseaseoccurs nowadays, its cause is usually not suspected. Furtherepidemiological study of the problem is necessary.