浓缩铀(UO_2F_2)诱发免疫活性细胞DNA合成刺激作用的研究

作者研究了不同水平浓缩铀（ＵＯ２Ｆ２）内污染机体后。对中枢和外周免疫活性细胞ＤＮＡ合成的刺激作用与免疫毒理效应．结果发现，当浓缩铀摄入量为１０～５００μｇ／ｋｇ体重时，脾Ｔ、Ｂ淋巴细胞和胸腺淋巴细胞３Ｈ－ＴｄＲ掺入显著降低（Ｐ＜０．０５或Ｐ＜０．０１），其ＤＮＡ合成呈现明显抑制效应．然而，当浓缩铀摄入量为０．１μｇ／ｋｇ体重时，脾ＰＨＡ反应性Ｔ淋巴细胞３Ｈ－ＴｄＲ掺入显著高于对照组（Ｐ＜０．０５），其ＤＮＡ合成呈现明显的刺激作用．诱发细胞增殖刺激作用的浓缩铀剂量与不同免疫活性细胞的辐射敏感性有关．应用数学方法拟合出不同免疫活性细胞的剂量效应曲线方程，呈直线平方模型．浓缩铀内污染１４天后，各免疫活性细胞３Ｈ－ＴｄＲ掺入率未见恢复正常．     

~(99m)Tc-ECD SPECT断层影像采血法和非采血法定量测定rCBF和CBF的对照研究

目的：应用９９ｍＴｃＥＣＤＳＰＥＣＴ断层影像采血和非采血法定量测定ｒＣＢＦ和ＣＢＦ。材料和方法：正常对照组１５例,疾病组１０例。采血法用动脉化静脉血样求得血中９９ｍＴｃＥＣＤ的浓度;非采血法用头颈平面像求得血中９９ｍＴｃＥＣＤ浓度。结果：正常对照组采血法ｒＣＢＦ２５０±４０～５９１±７６ｍｌ．ｍｉｎ－１·（１００ｇ）－１,ＣＢＦ４３０±３６ｍｌ．ｍｉｎ－１·（１００ｇ）－１;非采血法ｒＣＢＦ２６１±３２～６０３±６８ｍｌ．ｍｉｎ－１·（１００ｇ）－１,ＣＢＦ４３５±４４ｍｌ．ｍｉｎ－１·（１００ｇ）－１。和其他方法测得的正常值很接近。疾病组两法测定的结果基本一致。结论：用９９ｍＴｃ－ＥＣＤＳＰＥＣＴ断层影像测定ｒＣＢＦ和ＣＢＦ是可行的,可作为评价脑血流灌注的定量指标。     

介绍一种大鼠脑中γ-氨基丁酸受体的检测方法

目的：介绍一种大鼠脑中γ－ 氨基丁酸受体的快速简便的检测方法。方法：用３Ｈ－ ＧＡＢＡ 为配体来检测大鼠脑神经末梢微囊中的ＧＡＢＡ受体。检测ＧＡＢＡ受体的合适条件是１．０ ×１０－３ｍｏｌ／Ｌ的脑膜蛋白在３７℃下反应３０ ｍｉｎ。结果：大鼠脑中存在ＧＡＢＡ受体,Ｋｄ＝ （９７．３±５．８） ×１０－９ｍｏｌ／Ｌ,Ｂｍａｘ ＝０．１０６１ ×１０－９ｍｏｌ／ｇ 蛋白±０．０１０３×１０ －９ｍｏｌ／ｇ 蛋白,属低亲和力受体。结论：用３Ｈ－ ＧＡＢＡ可以检测大鼠脑中的ＧＡＢＡ受体。     

牛磺酸抑制激光血管成形术后体外培养的平滑肌细胞增殖和癌基因c-fos、c-myc的表达

本文在兔腹主动脉粥样硬化模型上，行激光血管成形术（ｌａｓｅｒａｎｇｉｏｐｌａｓｔｙ，ＬＡ），用体外培养的血管平滑肌（ｖａｓｃｕｌａｒｓｍｏｏｔｈｍｕｓｃｌｅｃｅｌ，ＶＳＭＣ）３Ｈ－ＴｄＲ掺入和癌基因ｃ－ｆｏｓ和ｃ－ｍｙｃ表达的测定，观察了牛磺酸对血管损伤后腹主动脉ＶＳＭＣ增殖的影响。结果显示：牛磺酸（３×１０－６～５×１０－３ｍｏｌ／Ｌ）能抑制体外培养ＶＳＭＣ３Ｈ－ＴｄＲ掺入，呈剂量依赖关系，５×１０－３ｍｏｌ／Ｌ抑制血清诱导ＶＳＭＣ中的ｃ－ｆｏｓ和ｃ－ｍｙｃ基因表达。     

高压氧对实验性腹膜粘连的防治作用(论著)

目的：探讨高压氧（ＨＢＯ）对实验性腹膜粘连的防治作用。方法：３６只Ｗｉｓｔａｒ大鼠采用创伤法复制实验性腹膜粘连动物模型，随机分为ＨＢＯ－Ａ组、ＨＢＯ－Ｂ组、ＨＢＯ－Ｃ组和对照组。ＨＢＯ－Ａ组和ＨＢＯ－Ｂ组于创伤后立即行ＨＢＯ治疗，分别治疗１０天和５天。ＨＢＯ－Ｃ组推迟５天才治疗，只治疗５天。创伤后１０天解剖所有大鼠，观察局部肠管色泽，并按腹膜粘连程度按级评分。结果：ＨＢＯ－Ａ组和ＨＢＯ－Ｂ组的腹膜粘连积分分别为１．２５±０．８９和１．６３±０．９２，显著低于对照组３．０８±０．７９（Ｐ＜０．０１），而ＨＢＯ－Ｃ组的腹膜粘连积分为２．８８±０．８３，与对照组相比无统计学差异（Ｐ＞０．０５）。结论：术后及时行ＨＢＯ治疗能防治实验性腹膜粘连。     

同种Beagle狗循环血造血干细胞移植治疗急性放射病的实验研究

实验中用Ｂｅａｇｌｅ狗１０只，以０．０２４７～０．０２７８Ｃ·ｋｇ－１·ｍｉｎ－１照射量率，全身照射６．５Ｇｙ，分３组：第１组３只，作为对照，不给任何治疗，照射后全部死亡，平均活存７．５天。第２组４只，移植性别相反的同种血造血干细胞。供受体混合淋巴细胞培养刺激指数小于０．６９，红细胞交叉凝集试验阴性，未在体外去除供体血细胞中的Ｔ淋巴细胞。结果表明，照射后１１，２０和２６天检查性染色体，均为供体核型。４只狗死于严重ＧＶＨＤ，平均活存４ｌ．６天。第３组３只，移植去除Ｔ淋巴细胞的同种血干细胞，２只死亡，１只发生轻度ＧＶＨＤ，长期活存４年以上。     

21天头低位(-6°)卧床前后下体负压和头高位倾斜暴露时的心血管反应

目的探讨２１天头低位（ＨＤＴ）卧床对人体立位应激下心血管反应的影响,以及比较下体负压（ＬＢＮＰ）和头高位倾斜（ＨＵＴ）两种立位应激下心血管反应的差异。方法６名受试者在２１天ＨＤＴ前、后分别进行ＬＢＮＰ（－４．００ｋＰａ／３ｍｉｎ、－６．６７ｋＰａ／３ｍｉｎ及－９．３３ｋＰａ／３ｍｉｎ）和ＨＵＴ试验（３０°／３ｍｉｎ、４５°／３ｍｉｎ、６０°／３ｍｉｎ及７５°／３ｍｉｎ）,以比较两种检测方法的血压（ＢＰ）和心率（ＨＲ）的变化情况。结果与ＬＢＮＰ（或ＨＵＴ）前相比：①ＬＢＮＰ（ＨＵＴ）时ＨＲ显著增加（Ｐ＜０．０１）,ＳＢＰ显著降低（Ｐ＜０．０５）;卧床后相应的变化量增加。②ＬＢＮＰ时ＤＢＰ降低（卧床后达显著,Ｐ＜０．０５）;而ＨＵＴ时ＤＢＰ增加（卧床后达显著,Ｐ＜０．０５）。③ＬＢＮＰ时ＭＡＰ均显著降低（Ｐ＜０．０５）;而ＨＵＴ时在卧床前无变化（Ｐ＞０．０５）,在卧床后显著增加（Ｐ＜０．０５）。结论ＬＢＮＰ和ＨＵＴ引起的ＣＶＳ反应并不相同。笔者认为,ＨＵＴ更能促进心血管系统对立位应激的调节作用。     

健康吸烟者与慢性阻塞性肺病患者肺内~（99m）Tc－DTPA清除率测定

测定了１３例健康非吸烟者、１１例健康吸烟者、１４例慢性阻塞性肺病（ＣＯＰＤ）非吸烟者及１８例ＣＯＰＤ吸烟者肺内９９ｍＴｃ－ＤＴＰＡ清除率的变化。结果：肺内９９ｍＴｃ－ＤＴＰＡ清除率在健康非吸烟组（１．３０８±０．３２１％·ｍｉｎ－１）与ＣＯＰＤ非吸烟组（１．６３２±０．５６６％·ｍｉｎ－１）之间无显著差异，而健康吸烟组（３．６０１±１．０１７％·ｍｉｎ－１）和ＣＯＰＤ吸烟组（３．２５±１．２７２％·ｍｉｎ－１）的清除率较两个非吸烟组显著增高。认为ＣＯＰＤ本身并不能引起肺上皮通透性的改变，而吸烟可使肺上皮通透性增加导致肺内９９ｍＴｃ－ＤＴＰＡ清除率增高，这些变化与气溶胶颗粒在肺内沉积部位的改变无关。     

浙江省天然本底辐射水平及其所致公众剂量

作者报道了浙江省天然本底辐射水平及其对公众所致的内、外照射剂量．结果表明：宇宙射线电离成分空气吸收剂量率人口加权平均值室外为３．０×１０（－８）Ｇｙ·ｈ（－１），室内为２．７×１０（－８）Ｇｙ·ｈ（－１），地表γ辐射空气吸收剂量率人口加权平均值室外为９．１×１０（－８）Ｇｙ·ｈ（－１）；室内为１４．９×１０（－８）Ｇｙ·ｈ（－１）；室内、室外空气中氡平均浓度分别为１７．２和１２．７Ｂｑ·ｍ（－３）；食品和水中天然放射性核素含量也分别进行了测定．由天然本底辐射所致公众人均年有效剂量总计为２．０ｍＳｖ，其中由宇宙射线，地表γ辐射，空气中氡、子体以及摄入天然放射性核素所致剂量分别为０．２４ｍＳｖ，０．７７ｍＳｖ，０．６７ｍＳｖ和０．３５ｍＳｖ，全省公众集体年有效剂量为８．５×１０４人·Ｓｖ．     

高压氧影响荷瘤鼠脾淋巴细胞增殖及天然杀伤细胞活性的研究

目的探讨ＨＢＯ对荷瘤鼠脾淋巴细胞增殖、天然杀伤细胞（ＮＫ）活性和脾指数的影响。方法将Ｂａｌｂ／Ｃ小鼠接种Ｓ－１８０瘤细胞,制成荷瘤鼠动物模型;经ＨＢＯ暴露（压力为０．２４ＭＰａ,氧浓度为８７％,每次暴露６０分钟,每日１次,共２０次后）,用３Ｈ－ＴｄＲ掺入法观察脾Ｔ淋巴细胞增殖能力和用３Ｈ－ＴｄＲ靶细胞释放法观察ＮＫ细胞杀伤活性。结果淋巴细胞增殖在ＨＢＯ组比正常对照组低（Ｐ＜０．０１）;肿瘤组比对照组低（Ｐ＜０．０１）;ＨＢＯ＋肿瘤组比肿瘤组低（Ｐ＜０．０１）;ＨＢＯ＋肿瘤组比ＨＢＯ组低（Ｐ＜０．０１）;肿瘤组比ＨＢＯ组低（Ｐ＜０．０１）。ＮＫ活性在对照组比肿瘤组高（Ｐ＜０．０５）;ＨＢＯ＋肿瘤组比肿瘤组高（Ｐ＜０．０５）。脾指数在各组之间无明显的变化（Ｐ＞０．０５）。结论ＨＢＯ暴露可降低正常鼠和荷瘤鼠脾淋巴细胞增殖能力。ＨＢＯ暴露对免疫功能的影响是多方面的,不能简单地说增强或减弱。本实验提示,ＨＢＯ暴露可能会使肿瘤接种引起的免疫功能低下程度减轻。     

放射损伤对鼻咽癌外周血CD4+CD25high调节性T细胞的影响

目的通过分析放疗前后鼻咽癌(NPC)患者外周血CD4+CD25high调节T(Tr)细胞比例及其变化规律.初步探讨NPC患者免疫抑制机制和放疗对免疫抑制的影响,为有效提高NPC的治疗疗效提供参考.方法采用流式细胞术检测36例初治的鼻咽癌患者放疗前、放疗后和30例正常健康者(对照组)外周血中T细胞亚群及CD4+CD25high T细胞比例.结果放疗前鼻咽癌患者CD3+、CD4+、CD8+T细胞比例及CD4/CD8比值接近正常对照组(P＞0.05);而CD4+CD25high Tr细胞比例明显高于正常对照组[分别为(2.76±1.06)%,(2.06±0.98)%,P＜0.05];放疗结束时,与放疗前比较,外周血CD4+T细胞比例减低、但差异无统计学意义(P＞0.05);CD4+/CD8+比值减低(P＜0.05),而CD4+CD25high Tr细胞比例明显升高,差异有统计学意义[(4.88±1.02)%,P＜0.05].结论CD4+CD25high Tr细胞可能是鼻咽癌患者免疫抑制的重要原因之一,与鼻咽癌免疫逃逸有关.放疗后外周血CD4+CD25high Tr细胞比例比CD4+/CD8+比值更能敏感反映免疫功能状态,有可能成为鼻咽癌的更有效的免疫监测指标.     

Evaluation of radiotherapeutic response in non-small cell lung cancer patients by technetium-99m MIBT and thallium-201 chloride SPET

The purpose of this study was to investigate the relationship between technetium-99m hexakis-2-methoxyisobutylisonitrile (^99mTc-MIBI) accumulation in tumours and response to radiotherapy in non-small cell lung cancer patients in comparison with the findings obtained using thallium-201 chloride (²⁰¹Tl).Simultaneous dual single-photon emission tomography (SPET) imaging with 600 MBq ^99mTc-MIBI and 111 MBq ²⁰¹Tl was performed in 31 patients with biopsy- or sputum cytology-proven lung cancer. SPET images were acquired 15 min (early) and 2 h (delayed) after injection, and the early ratio, delayed ratio and retention index were measured. The tumours were classified into two groups on the basis of follow-up computed tomography (CT): responders (at least 50% reduction in tumour size) and non-responders (little or no change in tumour size).The mean (± SD) values of early ratio, delayed ratio and retention index using ^99mTc-MIBI SPET were 3.0±1.1, 2.7±1.0 and –9.5±12.7, respectively, in responders and 2.4±0.7, 2.0±0.5 and –18.4±9.0, respectively, in non-responders. The corresponding values using ²⁰¹Tl chloride SPET were 3.7±1.0, 4.7±1.5 and 24.2±22.1 in responders and 3.3±1.2, 4.0±1.3 and 20.4±20.5 in non-responders. Using ^99mTc-MIBI, the delayed ratio and retention index in responders were significantly higher than those in non-responders (P<0.01 and P<0.05, respectively). The results of this study indicate that patients with higher delayed ratio and retention index values using ^99mTc-MIBI SPET are likely to respond better to radiotherapy than those with lower values. ^99mTc-MIBI SPET may give an indication of the short-term response to radiotherapy in patients with non-small cell lung cancer. Received 1 November 1999 and in revised form 8 January 2000     

Diffusion-weighted MR imaging including bi-exponential fitting for the detection of recurrent or residual tumour after (chemo)radiotherapy for laryngeal and hypopharyngeal cancers

Objectives

To assess whether diffusion-weighted magnetic resonance imaging (DW-MRI) including bi-exponential fitting helps to detect residual/recurrent tumours after (chemo)radiotherapy of laryngeal and hypopharyngeal carcinoma.

Methods

Forty-six patients with newly-developed/worsening symptoms after (chemo)radiotherapy for laryngeal/hypopharyngeal cancers were prospectively imaged using conventional MRI and axial DW-MRI. Qualitative (visual assessment) and quantitative analysis (mono-exponentially: total apparent diffusion coefficient [ADC_T], and bi-exponentially: perfusion fraction [F_P] and true diffusion coefficient [ADC_D]) were performed. Diffusion parameters of tumour versus post-therapeutic changes were compared, with final diagnosis based on histopathology and follow-up. Mann-Whitney U test was used for statistical analysis.

Results

Qualitative DW-MRI combined with morphological images allowed the detection of tumour with a sensitivity of 94% and specificity 100%. ADC_T and ADC_D values were lower in tumour with values 120 ± 49 × 10⁻⁵ mm²/s and 113 ± 50 × 10⁻⁵ mm²/s, respectively, compared with post-therapeutic changes with values 182 ± 41 × 10⁻⁵ mm²/s (P < 0.0002) and 160 ± 47 × 10⁻⁵ mm²/s (P < 0.003), respectively. F_P values were significantly lower in tumours than in non-tumours (13 ± 9% versus 31 ± 16%, P < 0.0002), with F_P being the best quantitative parameter for differentiation between post-therapeutic changes and recurrence.

Conclusions

DW-MRI in combination with conventional MRI substantially improves detection and exclusion of tumour in patients with laryngeal and hypopharyngeal cancers after treatment with (chemo)radiotherapy on both qualitative and quantitative analysis, with F_P being the best quantitative parameter in this context.

Key Points

• DW-MRI is increasingly used to detect tumour recurrence.

• DW-MRI allows accurate post-treatment recurrence detection in laryngeal or hypopharyngeal cancer

• ADC values in recurrent tumour are lower than in benign tissue alterations

• Both qualitative and quantitative DW-MRI approaches allow detection of recurrence

• DW-MRI can easily be added to daily clinical routine imaging

     

Intravoxel incoherent motion MR imaging: comparison of diffusion and perfusion characteristics between nasopharyngeal carcinoma and post-chemoradiation fibrosis

Objectives

To compare the intravoxel incoherent motion (IVIM) diffusion and perfusion characteristics of nasopharyngeal carcinoma (NPC) and post-chemoradiation fibrosis to aid in their differentiation.

Methods

Fifty-three (64 %) patients with newly diagnosed NPC and 30 (36 %) patients with biopsy-proven post-chemoradiation fibrosis were recruited into tumour and fibrosis groups respectively. Diffusion-weighted magnetic resonance (MR) imaging was performed using 13 b values (0–1,000 s/mm²). Their respective IVIM parameters (D, pure diffusion; f, perfusion fraction; D*, pseudodiffusion coefficient) were obtained.

Results

D and f were significantly lower in NPC (D?=?0.752?±?0.194?×?10^-3 mm²/s, P <0.001; f?=?0.122?±?0.095, P <0.001) than in fibrosis (D?=?1.423?±?0.364?×?10^-3 mm²/s; f?=?0.190?±?0.120); while D* was significantly higher in NPC (111.366?±?65.528?×?10^-3 mm²/s, P <0.001) than in fibrosis (77.468?±?62.168?×?10^-3 mm²/s). Respective cut-off values with sensitivity, specificity and accuracy were: D?=?1.062?×?10^-3 mm²/s (100 %, 100 %, 100 %); f?=?0.132 (66.0 %, 100 %, 78.3 %); D*?=?85.283?×?10^-3 mm²/s (100 %, 90.7 %, 96.4 %).

Conclusion

NPC and post-chemoradiation fibrosis have distinctive IVIM parameters. IVIM MR imaging is potentially useful in discrimination between NPC and fibrosis.

Key Points

? New MRI techniques offer greater help in the assessment of nasopharyngeal carcinoma. ? Tumour and post-chemoradiation fibrosis have distinctive intravoxel incoherent motion diffusion/perfusion parameters. ? Non-invasive IVIM MRI may help differentiate between tumour and fibrosis. ? Pure diffusion is a robust independent discriminating factor which improves diagnostic confidence.     

Detection of radiation‐induced lung injury using hyperpolarized 13C magnetic resonance spectroscopy and imaging

Radiation‐induced lung injury limits radiotherapy of thoracic cancers. Detection of radiation pneumonitis associated with early radiation‐induced lung injury (2–4 weeks postirradiation) may provide an opportunity to adjust treatment, before the onset of acute pneumonitis and/or irreversible fibrosis. In this study, localized magnetic resonance (MR) spectroscopy and imaging of hyperpolarized ¹³C‐pyruvate (pyruvate) and ¹³C‐lactate (lactate) were performed in the thorax and kidney regions of rats 2 weeks following whole‐thorax irradiation (14 Gy). Lactate‐to‐pyruvate signal ratio was observed to increase by 110% (P < 0.01), 57% (P < 0.02), and 107% (P < 0.01), respectively, in the thorax, lung, and heart tissues of the radiated rats compared with healthy age‐matched rats. This was consistent with lung inflammation confirmed using cell micrographs of bronchioalveolar lavage specimens and decreases in arterial oxygen partial pressure (p_aO₂), indicative of hypoxia. No statistically significant difference was observed in either lactate‐to‐pyruvate signal ratios in the kidney region (P = 0.50) between the healthy (0.215 ± 0.100) and radiated cohorts (0.215 ± 0.054) or in blood lactate levels (P = 0.69) in the healthy (1.255 ± 0.247 mmol/L) and the radiated cohorts (1.325 ± 0.214 mmol/L), confirming that the injury is localized to the thorax. This work demonstrates the feasibility of hyperpolarized ¹³C metabolic MR spectroscopy and imaging for detection of early radiation‐induced lung injury. Magn Reson Med 70:601–609, 2013. © 2012 Wiley Periodicals, Inc.     

电磁脉冲造成神经细胞氧化损伤效应研究

电磁脉冲(EMP)作为一种非电离辐射,生物效应广泛,从自由基生物学角度研究其对神经细胞的辐射损伤效应具有一定的实际意义.方法采用自旋捕捉的方法检测自由基的变化,TBA法检测脂质过氧化产物丙二醛(MDA),DTNB法检测谷胱甘肽过氧化物酶(GSH-px)的活性,MTT法检测细胞存活率,流式细胞术检测细胞内Ca2+浓度.结果电磁脉冲作用大鼠大脑皮层细胞和海马细胞后,脂氧自由基水平升高.MDA水平升高,大脑皮层细胞对照组MDA水平为(6.18±0.29)nmol/mg,EMP作用组为(8.43±0.01)nmol/mg(P＜0.01);海马细胞对照组MDA水平为(4.38±0.15)nmol/mg,EMP作用组为(4.98±0.39)nmol/mg(P＜0.05).GSH-px活性降低,大脑皮层细胞对照组A值为0.026±0.001,EMP作用组为0.022±0.002(P＜0.05),海马细胞对照组A值为0.021±0.002,EMP作用组为0.018±0.001(P＜0.05).电磁脉冲不能直接杀死细胞,其存活率约为95%,当脉冲数达到10次时,细胞内Ca2+浓度开始升高.结论电磁脉冲提高了神经细胞脂氧自由基水平,脂质过氧化产物MDA水平升高,GSH-px活性降低,预示氧化损伤效应的发生.另外,电磁脉冲不能直接杀死细胞,但可导致细胞内Ca2+浓度升高,增多的Ca2+可能成为诱发细胞凋亡的重要因素之一.     

Dosimetric evaluation of a three-phase adaptive radiotherapy for nasopharyngeal carcinoma using helical tomotherapy

Adaptive radiotherapy (ART) has been introduced to correct the radiation-induced anatomic changes in head and neck cases during a treatment course. This study evaluated the potential dosimetric benefits of applying a 3-phase adaptive radiotherapy protocol in nasopharyngeal carcinoma (NPC) patients compared with the nonadaptive single-phase treatment protocol. Ten NPC patients previously treated with this 3-phase radiation protocol using Hi-Art Tomotherapy were recruited. Two new plans, PII-ART and PIII-ART, were generated based on the up-to-date computed tomography (CT) images and contours and were used for treatment in phase two (PII; after 25th fraction) and phase three (PIII; after 35th fraction), respectively. To simulate the situation of no replanning, 2 hybrid plans denoted as PII-NART and PIII-NART were generated using the original contours pasted on the PII- and PIII-CT sets by CT-CT fusion. Dosimetric comparisons were made between the NART plans and the corresponding ART plans. In both PII- and PIII-NART plans, the doses to 95% of all the target volumes (D₉₅) were increased with better dose uniformity, whereas the organs at risk (OARs) received higher doses compared with the corresponding ART plans. Without replanning, the total dose to 1% of brainstem and spinal cord (D₁) significantly increased 7.87 ± 7.26% and 10.69 ± 6.72%, respectively (P = 0.011 and 0.001, respectively), in which 3 patients would have these structures overdosed when compared with those with two replannings. The total maximum doses to the optic chiasm and pituitary gland and the mean doses to the left and right parotid glands were increased by 10.50 ± 10.51%, 8.59 ± 6.10%, 3.03 ± 4.48%, and 2.24 ± 3.11%, respectively (P = 0.014, 0.003, 0.053, and 0.046, respectively). The 3-phase radiotherapy protocol showed improved dosimetric results to the critical structures while keeping satisfactory target dose coverage, which demonstrated the advantages of ART in helical tomotherapy of NPC.     

Histamine protects bone marrow against cellular damage induced by ionising radiation

Purpose:?Based on our previous data on the histamine radioprotective effect on small intestine, in the present work we aimed to determine whether histamine is able to protect bone marrow cells against ionising radiation damage.

Materials and methods:?56 mice and 40 rats were divided into four groups. Histamine and histamine-irradiated groups received a daily subcutaneous histamine injection (0.1?mg/kg) starting 24?h before irradiation. Irradiated groups received a single dose on whole-body using Cesium-137 source and were sacrificed three days after irradiation. We evaluated the number of medullar components, bone marrow trophism, oedema, vascular damage, and other histological characteristics and also proliferation markers by immunohistochemistry.

Results:?Histamine treatment substantially reduced the grade of aplasia, the oedema and vascular damage induced by ionising radiation on bone marrow of mice and rats. Additionally, histamine preserved medullar components increasing the number of megakaryocytes (14.0?±?1.0?vs. 7.3?±?1.0 in mice; and 9.9?±?1.3?vs. 4.1?±?1.0 in rats, P?<?0.01) and also myeloid (253.4?±?37.6?vs. 7.8?±?1.5 in mice; and 52.0?±?3.7?vs. 31.8?±?3.1 in rats, P?<?0.01), lymphoid (97.4?±?6.5?vs. 19.8?±?1.6 in mice; and 23.4?±?0.9?vs. 11.7?±?2.5 in rats, P?<?0.01) and erythroid cells (165.0?±?9.1?vs. 8.8?±?2.8 in mice; and 27.3?±?2.3?vs. 15.6?±?3.5 in rats, P?<?0.01) per mm². This effect was associated with an increased proliferation rate of bone marrow cells.

Conclusions:?Histamine reduces ionising radiation toxicity on bone marrow cells being a suitable candidate for use as radioprotector, especially for patients undergoing radiotherapy who are at the risk of bone marrow or small intestine damage.     

gamma-H2AX foci formation in peripheral blood lymphocytes of tumor patients after local radiotherapy to different sites of the body: Dependence on the dose-distribution,irradiated site and time from start of treatment

Purpose: To evaluate the relationship between an estimated integral total body radiation dose delivered and phosphorylated histone H2AX protein (γ-H2AX) foci formation in peripheral blood lymphocytes of cancer patients.

Material and methods: γ-H2AX formation was quantified as the mean number of foci per lymphocyte (N_meanH2AX) and the percentage of lymphocytes with ≥n foci. The integrated total body radiation dose was estimated from the dose volume histogram of patient's body corrected for the proportion of the body scanned by computed tomography for 3D treatment planning.

Results: There was a strong linear correlation between the mean number of γ-H2AX foci per lymphocyte in the peripheral blood sample and integrated total body radiation dose (r = 0.83, p < 0.0001). The slope of the relationship was dependent on the site of body irradiated. In comparison to chest irradiation with a slope of 8.7 ± 0.8 foci Gy^?1, the slopes for brain, upper leg and pelvic sites were significantly shallower by ?4.7, ?4.3, and ?3.8 Gy^?1, respectively (p < 0.0001), while the slope for upper abdomen irradiation was significantly larger by 9.1 ± 2.6 Gy^?1 (p = 0.0007). There was a slight time effect since the start of radiotherapy on the slopes of the in vivo dose responses leading to shallower slopes (?1.5 ± 0.7 Gy^?1, p = 0.03) later (≥10 day) during radiotherapy. After in vitro irradiation, lymphocytes showed 10.41 ± 0.12 foci per Gy with no evidence of inter-individual heterogeneity.

Conclusions: γ-H2AX measurements in peripheral lymphocytes after local radiotherapy allow the estimation of the applied integral body dose. The site and time dependence have to be considered.     

Functional MRI of the rat somatosensory cortex: Effects of hyperventilation

Functional mapping of the rat somatosensory cortex was performed with T₂*-sensitized MRI using a forepaw electrical stimulation model in α-chloralose-anesthetized rats at 7 T under both normocapnia and mild hyperventilation-induced hypocapnia. A highly localized activation area, consistent with the known somatosensory cortical region, was detected in all seven animals studied during hypocapnia and in five of the same animals during normocapnia. Quantitatively, hypocapnia was found to significantly increase both the size of the fMRl activation area (3.4 ± 0.6 mm² versus 1.5 ± 0.6 mm² in normocapnia, mean ± standard error, n = 7, P < 0.03) and the average fMRl signal intensity increase (3.4 ± 0.6% versus 2.7 ± 0.4%, n = 5, P < 0.05). The increased sensitivity of fMRl to functional activation may reflect a widened arterial-venous oxygenation difference resulting from an increased effective oxygen extraction during hyperventilation. The dependence of the fMRl response on the ventilation state underscores the need to control for physiological parameters in animal fMRl studies.