羊水细胞培养进行脊肌萎缩症的产前诊断

目的 应用错配聚合酶链反应-限制性片断长度多态性（PCR-RFLP）方法进行脊肌萎缩症（spinal muscular atrophy,SMA)的产前诊断。方法 基于运动神经元生存基因（SMN）的两个同源拷贝碱基的差异，通过羊水细胞培养，应用错配PCR-RFLP法对2例有SMA阳性家族史的胎儿进行产前基因诊断。结果 2例均无SMN基因外显子缺失。结论 SMN基因缺失检测技术是高效、快速的SMA产前诊断的方法。     

用稳定性同位素~(58)Fe中子活化法测定缺铁性贫血儿童膳食铁吸收率

本文报告了应用稳定性同位素~(58)Fe对三组缺铁性贫血儿童,分别摄取平衡膳、平衡膳加大豆蛋白膳和平衡膳加大豆蛋白加维生素C膳时,各组儿童膳食铁的吸收率。测定结果顺次分别为12.0±3.6％、10.7±4.7％和18.1±3.6％。后者高于前二者,差异显著。据此,作者同意国际营养性贫血咨询小组(INACG)以及大多数学者的主张,即大豆制品不利于或降低膳食铁的生物利用率(bioavailability)。本文并结合实验讨论了本法的原理、操作技术及误差控制等问题,评价了本法在类似工作中的重要意义。     

Intramedullary pilocytic astrocytomas — a clinical and morphological study after combined surgical and photon or neutron therapy

Ten patients suffering from intramedullary pilocytic astrocytomas (WHO-classification: astrocytoma grade I) were investigated catamnesticly. Combined surgery and radiotherapy was performed. Seven patients received neutron irradiation postoperatively. In four cases the neurological symptoms were improved after follow-up periods ranging from 33 to 89 months. The three other patients died after 6 to 21 months. The autopsy findings of a 14 year old child are presented. Our results are compared with reports in the literature. In addition, long-term problems of the spinal column are discussed. It seems that the combined surgical and neutron therapy improves the prognosis of pencil gliomas.     

Boron neutron capture therapy: Preliminary study of BNCT with sodium borocaptate (Na2B1 2H1 1SH) on glioblastoma

To plan the optimal BNCT using BSH for glioblastoma patients, the¹⁰B concentration in tumor and blood was investigated in 11newly diagnosed glioblastoma patients. All patients received 20 mg BSH/kgbody weight 2.5–16 hrs prior to tumor removal. The quantitativedistribution of ¹⁰B was determined by prompt gamma rayspectrometry and/or -track autoradiography. ¹⁰Bdistribution in tumors was heterogeneous, ± 25% of scatteringat the microscopic level, and the distribution was also heterogeneous at thetissue level. ¹⁰B concentration in blood decreased inbi-exponential decay as a function of the time after the end of theadministration. The T/B ratio showed non-exponential increase with largevariation. The maximum T/B ratio would be around 1. The tumor/normal brain(T/N) ratio of ¹⁰B concentration was 11.0 ± 3.2. The¹⁰B content in normal brain is originated in vascular¹⁰B in parenchyma, since the ¹⁰B content innormal brain to blood (N/B ratio) being compatible with the blood content inparenchyma. These values allow for BNCT, using thermal neutrons, on braintumors located less than approximately 3.3 cm in depth from the brainsurface of neutron incidence, providing that the dose on the normalendothelium is controlled to less than the tolerance limit. In ourpreliminary study of BNCT, a 31% 3-year survival was achieved overall for 16 glioblastoma patients and a 50% 2-year survival wasachieved on 8 glioblastoma patients in our recent dose escalation studybased on these data.     

Pharmacokinetics and boron uptake of BSH (Na2B12H11SH) in patients with intracranial tumors

We evaluated retrospectively the pharmacokinetics and boron uptakeof BSH (mercaptoundecahydrododecarborate) for Boron Neutron Capture Therapy(BNCT) in 123 patients undergoing craniotomy for intracranialtumors. The pharmacokinetics revealed that BSH could moveeasily from blood to the peripheral organs; itwas retained there and elimination was very slow.BSH after intra-arterial infusion (IA) was found tomove into the peripheral organs more easily thanafter intra-venous (IV) infusion.In patients with malignant glioma, the average valuesof boron concentration in tumor and the tumorto blood ratio (T/B ratio) after IA infusionwere 26.8 ± 19.5 g/g (range, 6.1–104.7 g/g)and 1.77 ± 1.30 (range, 0.47–6.65) respectively. Onthe other hand, after IV infusion the valueswere 20.9 ± 12.2 g/g (range, 7.0–39.7 g/g)and 1.30 ± 0.65 (range, 0.61–2.94) respectively. Thedifferences are not statistically significant. Boron uptake inmalignant glioma was about three times higher thanlow grade glioma. We found a good correlationbetween boron uptake and time interval from BSHinfusion, and 15–20 hours after BSH infusion theboron concentration in tumor was above 20 g/g¹⁰B in 69% of the malignant glioma patients;T/B ratio was above one in 75%, andabove two in 44% of them.We recommend intra-venous infusion of BSH clinically sinceit is safer, and results in sufficient boronconcentration in tumor, and the planned irradiation mightbe optimal around 15–20 hours after the BSHinfusion for treating malignant glioma.     

Enhanced survival of glioma bearing rats following boron neutron capture therapy with blood-brain barrier disruption and intracarotid injection of boronophenylalanine

Boronophenylalanine (BPA) has been used for boron neutron capture therapy (BNCT) of brain tumors in both experimental animals and humans. The purpose of the present study was to determine if the efficacy of BNCT could be enhanced by means of intracarotid (i.c.) injection of BPA with or without blood-brain barrier disruption (BBB-D) and neutron irradiation using a rat brain tumor model. For biodistribution studies, F98 glioma cells were implanted stereotactically into the brains of Fischer rats, and12 days later BBB-D was carried out by i.c. infusion of 25% mannitol (1.373 mOsmol/ml), followed immediately by i.c. administration of 300, 500 or 800 mg of BPA/kg body weight (b.w.). At the 500 mg dose a fourfold increase in tumor boron concentration (94.5 g/g) was seen at 2.5 hours after BBB-D, compared to 20.8 g/g in i.v. injected animals. The best composite tumor to normal tissue ratios were observed at 2.5 hours after BBB-D, at which time the tumor: blood (T: Bl) ratio was10.9, and the tumor: brain (T: Br) ratio was 7.5, compared to 3.2 and 5.0 respectively for i.v. injected rats. In contrast, animals that had received i.c. BPA without BBB-D had T: Bl and T: Br ratios of 8.5 and 5.9, respectively, and the tumor boron concentration was 42.7g/g. For therapy experiments, initiated 14 days after intracerebral implantation of F98 glioma cells, 500 mg/kg b.w. of BPA were administered i.v. or i.c. with or without BBB-D, and the animals were irradiated 2.5 hourslater at the Brookhaven Medical Research Reactor with a collimated beam of thermal neutrons delivered to the head. The mean survival time for untreated control rats was 24 ± 3 days, 30 ± 2 days for irradiated controls, 37 ± 3 days for those receiving i.v. BPA, 52 ± 15 days for rats receiving i.c. BPA without BBB-D, and 95 ± 95 days for BBB-D followed by i.c. BPA and BNCT. The latter group had a 246% increase in life span (ILS) compared to untreated controls and a 124% ILS compared to that of i.v. injected animals. These survival data are the best ever obtained with the F98 glioma model and suggest that i.c. administration of BPA with or without BBB-D may be useful as a means to increase the efficacy of BNCT.     

快中子加光子照射小鼠胸腔后心肌的病理改变

目的：观察快中子、光子及快中子光子混合射线照射小鼠胸腔后心肌的病理改变。方法：168只小鼠被随机分为中子组、光子组、混合线组（快中子加光子）。分别照射等效快中子、光子及快中子加光子混合射线,每个剂量点均在照射后第3，14和28天分别取6只小颈处死，开胸取出心脏后用10％福尔马林固定，常规切片HE染色后在光镜下观察。结果：在照射后第3、14天和28天，3组小鼠心肌的病理改变基本一致，无显著差异。结论：快中子加光子混合射线照射小鼠胸腔后， 不会加重心肌放射损伤，对临床应用混合射线治疗胸部肿瘤有一定的指导意义。     

Neutron reflectivity study of the swollen structure of polyzwitterion and polyeletrolyte brushes in aqueous solution

The swollen brush structures of polycation and zwitterionic polymer brushes, such as poly(2-methacryloyloxyethyltrimethylammonium chloride) (PMTAC), poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), and poly[3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate] (PMAPS), in aqueous solutions of various ionic strengths were characterized by neutron reflectivity (NR) measurements. A series of the polyelectrolyte brushes were prepared by surface-initiated controlled radical polymerization on silicon substrates. A high-graft-density PMTAC brush in salt-free water (D₂O) adopted a two-region step-like structure consisting of a shrunk region near the Si substrate surface and a diffuse brush region with a relatively stretched chain structure at the solution interface. The diffuse region of PMTAC was reduced with increase in salt (NaCl) concentration. The PMAPS brush in D₂O formed a collapsed structure due to the strong molecular interaction between betaine groups, while significant increase in the swollen thickness was observed in salt aqueous solution. In contrast, no change was observed in the depth profile of the swollen PMPC brush in D₂O with various salt concentrations. The unique solution behaviors of zwitterionic polymer brushes were described.     

Novel α + β Zr Alloys with Enhanced Strength

Low-alloyed zirconium alloys are widely used in nuclear applications due to their low neutron absorption cross-section. These alloys, however, suffer from limited strength. Well-established guidelines for the development of Ti alloys were applied to design new two-phase ternary Zr alloys with improved mechanical properties. Zr-4Sn-4Nb and Zr-8Sn-4Nb alloys have been manufactured by vacuum arc melting, thermo-mechanically processed by annealing, forging, and aging to various microstructural conditions and thoroughly characterized. Detailed Scanning electron microscopy (SEM) analysis showed that the microstructural response of the alloys is rather similar to alpha + beta Ti alloys. Duplex microstructure containing primary alpha phase particles surrounded by lamellar alpha + beta microstructure can be achieved by thermal processing. Mechanical properties strongly depend on the previous treatment. Ultimate tensile strength exceeding 700 MPa was achieved exceeding the strength of commercial Zr alloys for nuclear applications by more than 50%. Such an improvement in strength more than compensates for the increased neutron absorption cross-section. This study aims to exploit the potential of alpha + beta Zr alloys for nuclear applications.     

Extended set of activation monitors for NCT beam characterization and spectral conditions of the beam after reactor fuel conversion

Since 2010 the LVR-15 reactor has been gradually converted from highly enriched fuel (36 wt% ²³⁵U) to low enriched fuel with the enrichment of 19.75 wt% ²³⁵U. Paper presents influence of the core pattern changes on the neutron characteristics of the epithermal beam. The determination of neutron spectrum free in the beam was done with a set of neutron activation monitors. After the reactor conversion the change in neutron spectrum is not provable as differences are in the range of measurement errors.