Denture disinfection by microwave irradiation: A randomized clinical study

Objective

This study evaluated the clinical effectiveness of two exposure times of microwave irradiation on the disinfection of complete dentures.

Methods

Biofilm samples were collected from dentures of 30 patients, who were randomly divided into two experimental groups of 15 subjects each: Group 1—patients had their maxillary denture microwaved for 3 min (650 W); Group 2—patients had their maxillary denture microwaved for 2 min (650 W). Denture biofilm samples were taken with swabs, before (left side surfaces) and after (right side surfaces) microwave irradiation. All microbial material was plated on selective media for Candida spp., Staphylococcus spp., mutans streptococci and a non-selective media. After incubation (48 h/37 °C), the number of colony-forming units (cfu/mL) was counted. Microorganisms which grew on selective media were identified using biochemical methods. The data were statistically analyzed by Kruskal–Wallis test, followed by Dunn's post-test (α = 0.05).

Results

Microwave irradiation for 3 min (Group 1) resulted in sterilization of all dentures evaluated. After microwave irradiation for 2 min (Group 2), a significant decrease in Candida spp. (P = 0.0062), Staphylococcus spp. (P = 0.0178), mutans streptococci (P = 0.0047) and non-identified species (P < 0.0001) was achieved in comparison with the cfu/mL obtained before irradiation. The colonies grown after 2 min of microwave irradiation were identified as Candida albicans, non-aureus Staphylococci and Streptococcus mutans.

Conclusion

Microwave irradiation for 3 min may be a potential treatment to prevent cross-contamination.     

微波照射预处理对兔肝内源性一氧化氦影响的实验研究

目的：观察微波照射对兔肝脏缺血再灌注损伤中的肝功能ALT、AST、LDH、肝组织匀浆一氧化氮（NO）、一氧化氮合酶（NOs）的变化，并探讨其保护机制。方法：32只新西兰大白兔被随机分为A、B、C、D共4组。各组于术后2h、4h抽血查ALT、AST、LDH。实验结束处死获取肝脏标本，检测各组的NO、NOs并行HE染色。结果：B、C、D三组的ALT、AST、LDH显著高于A组。而C、D组的NO、NOS显著低于A、B两组，其中D组又显著低于C组。C组病理改变明显轻于D组。结论：适宜条件的微波照射预处理能明显改善缺血再灌注损伤的肝功能，减轻肝细胞损伤，而NO是该保护机制中的一个重要因素。     

分米波对股骨头缺血性坏死影响的实验研究

目的：探讨分米波在预防和治疗股骨头缺血性坏死中的作用及意义。方法：给家兔肌肉注射糖皮质激素７．５ｍｇ／ｋｇ体重，每周１次，制备股骨头缺血性坏死模型，应用分米波治疗一侧，另一侧作自身对照，以组织病理切片、印度墨汁法灌注及冰冻脂肪染色为观察指标。结果：分米波治疗侧股骨头血管扩张明显高于未治疗侧，两组间差异有非常显著性（Ｐ＜０．０１），血管通透性降低，渗出液减少。治疗侧股骨头脂肪细胞体积较对照侧小且坏死出现早，从而有效地降低股骨头骨内压。结论：分米波可减轻股骨头缺血性坏死的程度和范围     

微波原位灭活联合人工关节假体置换治疗四肢恶性骨肿瘤的疗效分析

 目的 探讨微波原位灭活联合人工假体置换术治疗四肢恶性骨肿瘤（侵袭范围超过骨全长2/3）的可行性。方法 2001年6月至2012年4月对19例侵袭范围超过骨全长2/3的原发恶性骨肿瘤及转移瘤患者采用微波灭活联合假体置换术进行治疗。男12例, 女7例;年龄11~65岁, 平均47岁。原发恶性骨肿瘤11例,转移瘤8例。股骨远端8例、胫骨近端6例、肱骨近端3例、股骨近端2例。术前X线、CT显示骨干皮质破坏小于骨全长的1/3,而MRI显示肿瘤侵袭范围超过骨全长2/3。依据MRI确定截骨范围,定制肿瘤型人工假体。采用常规肿瘤假体置换入路,按广泛切除原则充分显露瘤段骨及软组织肿块。使用铜网保护瘤段骨周围软组织,用2 450 MHz微波将瘤段骨内部加热到50 ℃,持续20 min,按术前测量长度进行截骨,人工关节假体重建,逐层缝合组织及皮肤。结果 手术时间平均100 min,术中失血量平均600 ml。随访10个月~5年,平均2.7年。原发恶性骨肿瘤患者中1例术后出现复发,带瘤生存;2例术后其他部位转移,死亡;余8例随访期间未出现复发或转移。6例转移瘤患者分别于术后5~20个月出现其他部位转移,死亡;2例随访期间未出现原位复发或转移。3例肱骨近端肿瘤患者术后肩关节外展、上举功能受限,其余患者无关节功能受限。结论 微波灭活联合人工假体置换术治疗髓腔内广泛受累的四肢恶性骨肿瘤,能最大限度地保留术后患者的肢体功能。     

Design and analysis of annular antenna arrays with different reflectors

The design and performance of annular antenna arrays with reflectors is presented. Arrays with three shapes of reflectors are analysed and simulated. These include the corner reflector, the circular reflector and the elliptical reflector. Power-density distributions within the annular arrays with and without reflectors are obtained by using the FDTD method. Also, the image theory method is used to verify the FDTD results in one case. By comparing the power-density distribution pattern of all four of the array designs (three with different reflectors, one without reflector), it is readily seen in each case that the array with reflectors yields better power-efficiency than the array without reflectors and the elliptical reflector yields the best performance. Comparisons of each array are made using 4, 6 and 8 antennae in the annular array. By using the optimized results of the elliptical reflector, the requirement for the input-power level to each antenna is greatly reduced.     

能量多普勒造影评价微波治疗肝癌效果的应用

目的 探讨能量多普勒造影对微波治疗后肝癌血管的显像效果。方法 15例肝癌（24个病灶）1～2次微波治疗后经外周静脉注射Levovist观察癌内及癌旁造影前后的血流显像，并与病理结果相对照。结果 微波治疗后24个癌灶造影前无一例有血流显示。造影后19个病灶无血流显示者病理为完全性坏死；5个病灶有血流显示（1例瘤内，4例瘤旁），相应部位活检为完全性坏死，追加二次微波治疗，造影后未见血流显像，病理证实为完全坏死。结论 能量多普勒造影是评价微波治疗肝癌疗效的实用性方法之一。     

扩展经皮微波凝固肝组织范围的实验研究

目的：探索扩展经皮微波凝固肝组织范围的有效途径，提高较大肝癌的根治率，并减少穿刺次数。方法：用自行研制的HM－WIA型微波治疗仪对离体新鲜猪肝及活体实验兔、猪肝行微波凝固，观察天线长度、微波功率、时间、组织血流对凝固范围及形态的影响。结果：运用改进的单微波电极、中强度微波功率（45－55W）对离体、活体缺血组织行长时间（15－19min)凝固，最大凝固短径分别达5.6cm、5.3cm，凝固体积达文献的3倍；实验发现天线长36mm时凝固形态最佳；活体组织缺血凝固体积为正常供血凝固时的2.8倍（P＜0．05）。结论：采取“缺血后微波凝固策略”，运用改进的微波电极、中强度微波功率、长时间凝固有效地扩大了凝固范围，这将有利于提高肝癌尤其大肝癌的疗效，并明显减少穿刺次数。     

超声引导下植入式微波热场在体模中的研究

目的 探讨植入式微波在仿肝组织体模中热场的分布规律。方法 在体模实验中每次精确布16个点，每点重复5～9次，测量温度的分布，并求解组织的比吸收率（special absorption rate,SAR）。在Pennes生物热方程的基础上，推导建立肝癌植入式微波热疗的热作用数学模型，借助有限元法对三种加热功率、作用时间（60W5min、50W10min、40W30min）下温度分布进行广泛的模拟计算和预测。结果 通过体模实验确定了SAR分布。在r方向呈指数衰减，θ方向为余弦拟合，z方向呈三次多项式拟合，且前向温升大于后向。三种功率下SAR分布不同，并且SAR与功率分布之间没有线性关系。在SAR基础上，计算机动态模拟重建微波热场。结论 肝体模实验证明微波热场的分布呈以天线为中心向外有规律的依次递减，该规律可通过计算机模拟重建，模拟重建的热场具有三维动态连续监测的特点。这为临床微波治疗肝癌中有效调控热场的温度奠定了理论和技术基础。     

超声引导微波热凝固结合肝动脉栓塞化疗治疗肝癌

目的　评价肝癌肝动脉栓塞化疗后联合微波热凝固治疗的效果和安全性。方法　 18例经组织学证实的肝癌患者 ,14例为原发性肝癌 ,4例为转移癌。共 2 8个结节 ,肝动脉栓塞化疗后 1～ 2d内进行超声引导下微波热凝固治疗。结果　 19个直径 <5cm的结节完全性坏死 ,9个直径≥ 5cm的结节中 5个完全坏死 ,无严重并发症发生。结论　肝动脉栓塞联合超声引导下微波热凝固是治疗肝癌的一种有效方法     

Local microwave hyperthermia (43° C) and stimulation of the macrophage and T-lymphocyte systems in treatment of Guerin epithelioma in rats

Summary Rats bearing Guerin epithelioma were exposed to 3 or 6 sessions of local microwave hyperthermia (LMwH) (2450 MHz, tumor temperature 43° C, time of exposition 45 min) on the 3rd or 5th week after implantation of tumor cells. In some of the animals LMwH was combined with the administration of immunopotentiating (IP) substances—purified Streptolysin S (SLS) (1 mg/kg b.w.) or Corynebacterium parvum (CP) (1 mg/kg b.w., intratumorally)-injected 3 times weekly on the 4th and 6th weeks after implantation of tumor cells. All the animals were immunized with bovine serum albumine (BSA) 2 and 3 weeks after tumor implantation. Size of tumors was measured each 4 days and the growth curves were analysed. Eight weeks after implantation all the animals were killed and the following tests were performed: weight of tumors, BSA antibodies titre (passive hemagglutination test using BSA-glutaraldehyde coupled sheep red blood cells), ³H-leucine and ³H-uridine incorporation to phytohemagglutinin (PHA)-stimulated spleen lymphocytes and to mixed tumor cell-lymphocyte cultures, cytotoxicity of isolated spleen lymphocytes and peritoneal macrophages to ⁵¹Cr-labeled primary cultures of Guerin tumor cells, lysozyme (muramidase) activity in blood serum.LMwH inhibited growth of Guerin tumors and the effect was enhanced by combined treatment with IP substances. Combined application of LMwH and CP resulted in complete disappearance of 9 of 12 tumors, while LMwH and IP applied separately led to eradication of 2–5 tumors of 12.LMwH stimulated reactivity of the T-lymphocyte and macrophage systems enhancing both non-specific (increased production of BSA antibodies, high reactivity of spleen lymphocytes to PHA, increased serum lysozyme levels) and specific (increased cytotoxicity of lymphocytes and macrophages to cultured tumor cells and higher reactivity of lymphocytes to mitomycin-inhibited tumor cells) immune responses.The role of immunostimulation by LMwH is stressed as an important factor in tumor-inhibiting effect of hyperthermia in addition to the well known selective heat killing of neoplastic cells.This work was supported by research grants 05-339-C from the US Public Health Service and PR-6-210-02 from the Polish Governmental Program