腹盆腔放疗诱发肠道微生态失调与肠源性感染的实验研究

目的 探索腹盆腔放疗照射对肠道微生态的影响及其与肠源性感染的关系。方法 模拟腹盆腔放疗照射BALB/c小鼠,2.0 Gy/d,连续照射5 d/周,分别于照射3周、5周和6周后停照1周的时间点收集回肠组织及其内容物样本。用实时定量RT-PCR检测抗菌肽和促炎性因子的表达;用PCR检测细菌在小鼠体内的移位情况;用变性梯度凝胶电泳技术检测分析肠道微生态的特征。结果 腹盆腔照射诱发了肠道潘氏细胞隐窝素-1和-4表达紊乱,照射3周或照射6周后停照1周,小鼠回肠隐窝素-1和-4均呈现显著性降低(t=-7.43、-3.54、-4.72、-4.27,P<0.05);而照射5周小鼠回肠隐窝素-1和-4表达明显升高(t=6.15、5.75,P<0.05)。放疗模拟照射3和5周时小鼠肠道微生物区系多样性指数和丰富度显著降低(t=-3.49、-4.19、-3.44、-4.97,P<0.05),呈现以乳酸杆菌等益生菌减少,大肠杆菌和弗氏志贺氏菌等条件致病菌增多为特征的微生态失调。受照小鼠肠系膜淋巴结和血液中的细菌DNA阳性率明显增高。照射3和5周后回肠组织IL-1β、IL-6和TNF-α显著性高表达(t=4.85、6.16、7.71、4.60、4.86、5.97,P<0.05);照射6周后停照1周时,肠道促炎性因子的表达量有所回落,但IL-1β和TNF-α的表达量仍显著性高表达(t=3.67、5.88,P<0.05)。结论 腹盆腔放疗可诱发肠道抗菌肽表达紊乱,引起肠道微生态失调,进而导致肠源性细菌移位及感染性炎症的发生。微生态可能成为减轻放疗患者消化道不良反应的有效干预靶点。     

赤峰市饮用水中的总放射性水平调查

目的 了解赤峰市饮用水中的总放射性水平,估算由饮用水摄入放射性核素所致辐射年均有效剂量。方法 在赤峰市12个旗县区布点采集水样,用低本底α、β放射性测量仪和高纯锗γ能谱仪进行测量。结果 本次调查的赤峰市饮用水中的总α放射性水平为0.016~1.230 Bq/L,总β放射性水平为0.039~0.878 Bq/L。居民通过饮用自来水摄入总α放射性所致辐射年均有效剂量为0.071 mSv/年。结论 本次调查的赤峰市饮用水中的总α总β平均值低于世界卫生组织(WHO)的指导值,居民饮用自来水所致辐射年均有效剂量在安全水平之下。     

冠心病介入诊疗中透视与电影辐射剂量率对比分析

目的：研究冠心病患者介入诊疗中DSA设备显示的实时辐射剂量率,为医务人员合理控制辐射剂量提供依据。方法随机抽取2014年9月采用美国通用公司DSA机介入诊疗的冠心病患者30例,对术中DSA机由透视模式转换为电影模式时各自序列显示的辐射剂量率进行对比分析。结果透视辐射剂量率为18．5～212．0 mGy/min,均值为（114．7±42．1） mGy/min;电影辐射剂量率为216～1691 mGy/min,均值为（970．1±298．4） mGy/min。透视与电影辐射剂量率总体均值之比为1︰8．5。数字平板探测器面积越大,辐射剂量率均值越大,电影辐射剂量率均值较透视辐射剂量率均值增高趋势越明显;透视辐射剂量率均值较电影辐射剂量率均值低,差异显著。结论医务人员在冠心病介入诊疗中应合理选择 DSA 设备类型,密切观察动态实时显示的辐射剂量率,及时调整检查模式及可控参数,即刻评估可能致患者放射损伤的剂量水平,合理控制辐射剂量,以降低电离辐射对人体健康产生的辐射效应。     

68Ga标记的SSR靶向多肽PET/CT显像的研究进展及其在神经内分泌肿瘤中的初步应用

近年来,68Ga标记的多肽PET/CT显像为神经内分泌肿瘤（NET）的诊断提供了新的方法和视角。68Ge/68Ga发生器已经商业化,容易获得,并且68Ga标记过程简单方便,显像剂稳定性好。在此基础上,越来越多的研究比较了68Ga标记的多肽PET/CT与传统的形态学显像方法（CT、MRI）及生长抑素受体扫描对NET病灶的诊断效能,发现68Ga标记的多肽PET/CT远远优于后者。此外,68Ga标记的多肽PET/CT显像还能为患者治疗方案的选择、辐射剂量的调整甚至预后效果的评估提供多种重要信息,其有望成为NET患者肿瘤显像的临床首选。笔者就近年来68Ga标记的多肽PET/CT显像在临床上的初步应用研究作一综述。     

Natural Polyphenols Enhance Stability of Crosslinked UHMWPE for Joint Implants

Background

Radiation-crosslinked UHMWPE has been used for joint implants since the 1990s. Postirradiation remelting enhances oxidative stability, but with some loss in strength and toughness. Vitamin E-stabilized crosslinked UHMWPE has shown improved strength and stability as compared with irradiated and remelted UHMWPE. With more active phenolic hydroxyl groups, natural polyphenols are widely used in the food and pharmaceutical industries as potent stabilizers and could be useful for oxidative stability in crosslinked UHMWPE.

Questions/purposes

We asked whether UHMWPE blended with polyphenols would (1) show higher oxidation resistance after radiation crosslinking; (2) preserve the mechanical properties of UHMWPE after accelerated aging; and (3) alter the wear resistance of radiation-crosslinked UHMWPE.

Methods

The polyphenols, gallic acid and dodecyl gallate, were blended with medical-grade UHMWPE followed by consolidation and electron beam irradiation at 100 kGy. Radiation-crosslinked virgin and vitamin E-blended UHMWPEs were used as reference materials. The UHMWPEs were aged at 120 °C in air with oxidation levels analyzed by infrared spectroscopy. Tensile (n = 5 per group) and impact (n = 3 per group) properties before and after aging as per ASTM F2003 were evaluated. The wear rates were examined by pin-on-disc testing (n = 3 per group). The data were reported as mean ± SDs. Statistical analysis was performed by using Student’s t-test for a two-tailed distribution with unequal variance for tensile and impact data obtained with n ≥ 3. A significant difference is defined with p < 0.05.

Results

The oxidation induction time of 100 kGy UHMWPE was prolonged to 144 hours with 0.05 wt% dodecyl gallate and 192 hours with 0.05 wt% gallic acid compared with 48 hours for 0.05 wt% vitamin E-blended UHMWPE. Accelerated aging of these polyphenol-blended UHMWPEs resulted in ultimate tensile strength of 50.4 ± 1.4 MPa and impact strength of 53 ± 5 kJ/m² for 100 kGy-irradiated UHMWPE with 0.05 wt% dodecyl gallate, for example, in comparison to 51.2 ± 0.7 MPa (p = 0.75) and 58 ± 5 kJ/m² (p = 0.29) before aging. The pin-on-disc wear rates of 100 kGy-irradiated UHMWPE with 0.05 wt% dodecyl gallate and 0.05 wt% gallic acid were 2.29 ± 0.31 and 1.65 ± 0.32 mg/million cycles, comparable to 1.68 ± 0.25 and 2.05 ± 0.22 mg/million cycles for 100 kGy-irradiated virgin and 0.05 wt% vitamin E-blended UHMWPE.

Conclusions

Based on the sample numbers tested in this study, polyphenols appear to effectively enhance the oxidation stability without altering the mechanical properties or pin-on-disc wear rate of radiation-crosslinked UHMWPE.

Clinical Relevance

Crosslinked UHMWPE with natural polyphenols with improved oxidative stability and low wear may find clinical application in joint implants.     

B‐Type Natriuretic Peptide Levels Predict Ventricular Arrhythmia Post Left Ventricular Assist Device Implantation

B‐type natriuretic peptide (BNP) levels have been shown to predict ventricular arrhythmia (VA) and sudden death in patients with heart failure. We sought to determine whether BNP levels before left ventricular assist device (LVAD) implantation can predict VA post LVAD implantation in advanced heart failure patients. We conducted a retrospective study consisting of patients who underwent LVAD implantation in our institution during the period of May 2009–March 2013. The study was limited to patients receiving a HeartMate II or HeartWare LVAD. Acute myocardial infarction patients were excluded. We compared between the patients who developed VA within 15 days post LVAD implantation to the patients without VA. A total of 85 patients underwent LVAD implantation during the study period. Eleven patients were excluded (five acute MI, four without BNP measurements, and two discharged earlier than 13 days post LVAD implantation). The incidence of VA was 31%, with 91% ventricular tachycardia (VT) and 9% ventricular fibrillation. BNP remained the single most powerful predictor of VA even after adjustment for other borderline significant factors in a multivariate logistic regression model (P < 0.05). BNP levels are a strong predictor of VA post LVAD implantation, surpassing previously described risk factors such as age and VT in the past.     

Posteromedial thigh (PMT) propeller flap for perineoscrotal reconstruction: A case report

Fournier's gangrene can lead to extensive defects of the perineoscrotal area with exposure of the testes. Such defect poses challenging tasks for both functional and cosmetic reconstruction. Due to its proximity, medial thigh skin appeared to be the most versatile donor site for perineoscrotal reconstruction. In this report, we present a case of reconstruction of a large perineoscrotal defect because of Fournier's gangrene using a posteromedial thigh (PMT) perforator propeller flap. A 58 year‐old male who suffered from Fournier's gangrene resulted in a scrotal defect of 10 × 12 cm² with a large dead space. A pedicled PMT propeller flap measuring 9 × 23 cm² with two perforators that originated from the profunda femoris artery (PFA) was harvested for scrotal defect reconstruction and dead space obliteration. The flap survived completely, with no recipient or donor site morbidity. The length of followup was 3 months and was uneventful. The pedicled PMT propeller flap may be considered as a valid option for perineoscrotal reconstruction. © 2015 Wiley Periodicals, Inc. Microsurgery 35:569–572, 2015.