Disease relevance of Neutrons

• Effect of combined misonidazole and d(50)-Be neutrons on a human melanoma transplanted into nude mice [1].
• A novel K-ras mutation in codon 146 has been found in thymic lymphomas induced by neutrons [2].
• Highly localized energy depositions come from Auger emitters such as 125I and by the neutron capture therapy, where boron-10 in the tumor cell is exposed to thermal neutrons for initiating the B10 (n; alpha) Li7 reaction, especially for treating neuro- and glioblastoma and melanoma [3].
• PURPOSE: To determine the efficacy of WR-151327 (WR) [S-3-(3-methylaminopropylamino) propylphosphorothioic acid; (CH3-HN-(CH2)3-NH-(CH2)3-S-PO3H2)] in increasing resistance to bacterial infection after a sublethal dose of gamma-photons or mixed-field neutrons plus gamma-photons [4].
• Pretreatment with hyperthermia did significantly increase the breakage and chromosome loss induced by 0.85-MeV fission neutrons from the JANUS biological research reactor in spermatozoa, early and late spermatids and spermatocytes [5].

High impact information on Neutrons

• Efficacy of brachytherapy with californium-252 neutrons versus cesium-137 photons for eradication of bulky localized cervical cancer: single-institution study [6].
• Young adult female rats of either the Sprague-Dawley stock or the ACI strain were each given an implant of a compressed pellet of 5 mg diethylstilbestrol (DES) and 15 mg cholestrol 2 days before irradiation with 0.4, 1.3, or 4.0 rads of 0.43-MeV neutrons [7].
• In addition, we describe a more generally applicable "indirect-labeling" method in which separated compounds of interest are selectively bound to ligands containing highly neutron-activatable elements, such as manganese (55Mn), europium (151Eu), or dysprosium (164Dy), and then irradiated with thermal neutrons [8].
• Tryptophan hydroxylase was localized by light and electron immunohistochemistry to serotonin neutrons of the raphe [9].
• In the present study, we have investigated the potential use of boronated EGF as a delivery agent for boron neutron capture therapy, which is based on the capture reaction that occurs when 10B, a stable isotope, is irradiated with low-energy thermal neutrons [10].

Chemical compound and disease context of Neutrons

• CONCLUSION: The intratumoral administration of the hydrophilic magnetic resonance imaging contrast medium gadopentetate dimeglumine prior to irradiation with thermal neutrons leads to a therapeutic gain (i.e., reduction) on experimental Jensen sarcomas [11].
• Adenocarcinomas of the lung were seen in rats exposed to uranium oxide without subsequent irradiation by neutrons in the reactor and in rats irradiated with neutrons but not previously exposed to uranium oxide [12].

Biological context of Neutrons

• BACKGROUND: Boron neutron capture therapy (BNCT) is based on the nuclear reaction that occurs when boron-10 is irradiated with low-energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei [13].
• These studies demonstrate that high LET radiations (fission neutrons) can transform immortalized human epithelial cells to a malignant phenotype that does not appear to involve mutations in either the cellular p53 or ras genes [14].
• Relative biological effectiveness (RBE) of p(26) + Be neutrons from the King Faisal Specialist Hospital and Research Centre CS-30 cyclotron measured by testis weight loss [15].
• Chromosome aberration of human peripheral blood lymphocytes exposed to californium-252 (252Cf) neutrons transmitted through a 15 cm thick iron block was analysed [16].
• The induction of DNA strand breaks by fission neutrons was studied in aqueous plasmid (pBR322) DNA under aerobic conditions for a wide range of hydroxyl radical (*OH) scavenger concentrations and was compared to the induction of strand breaks by 6OCo gamma rays [17].

Anatomical context of Neutrons

• These studies revealed that neutrons repressed VL30 RNA accumulation evident within 10 min following exposure in brain, gut, thymus and spleen but not in liver, in which VL30 RNA was unaffected by radiation exposure [18].
• RESULTS: The development of acquired cis-platinum resistance conferred collateral resistance to 62.5 MeV (p--Be+) neutrons in all five cell lines, but did not consistently decrease the photon sensitivity of these same cells [19].
• PURPOSE: To investigate the protective effects of dimethyl sulfoxide (DMSO) on cell killing and mutagenicity at the HPRT locus in Chinese hamster ovary (CHO) cells against thermal and epithermal neutrons produced at the Kyoto University Research (KUR) reactor [20].
• The relative biological effectiveness of neutrons at 50% reductions of testis weight, primary spermatocytes, and elongated spermatids were 2.5, 10.0 and 6.1, respectively [21].
• The aim of this study was to investigate the responsiveness of the epithelium of the colon of the rat to electrical and pharmacological (serotonin, carbachol) stimulation concomitantly with in vivo assessment of the absorptive capacity of the colon at 1, 3, 5 and 7 days after 3.8 Gy whole-body exposure to neutrons [22].

Associations of Neutrons with chemical compounds

• With a multiaxial retrospective analysis, the overall survival of this study group appears to be least equivalent to that reported with 6,000 photon rad alone or of neutrons, and compares favorably to that achieved with combined 6,000 photo rad plus 5-fluorouracil [23].
• Boron neutron capture therapy (BNCT) is a form of radiation therapy mediated by the short-range (less than 10 microns) energetic alpha (4He) and lithium-7 (7Li) ionizing particles that result from the prompt disintegration by slow neutrons of the stable (nonradioactive) nucleus boron-10 (10B) [24].
• Comment on "giant absorption cross section of ultracold neutrons in gadolinium" [25].
• The triton fragments originating from this channel were detected in coincidence with the two neutrons [26].
• A consequence of the native interaction between neutrons and biological samples is that the hydrogen isotopes (1)H and (2)H are most significant in dynamical and structural studies, respectively [27].

Gene context of Neutrons

• To determine whether neutron-induced cellular transformation involves ras mutation, C3H10T1/2 cells were exposed to a single dose of 5.9 MeV neutrons [28].
• Delayed expression of hpS2 and prolonged expression of CIP1/WAF1/SDI1 in human tumour cells irradiated with X-rays, fission neutrons or 1 GeV/nucleon Fe ions [29].
• This indicates that radiation-induced apoptosis is mostly due to double strand breaks (DSBs) in DNA because we previously obtained almost the same RBE value of fission neutrons for the induction of crossover mutations in Drosophila melanogaster, which arise from the recombinational repair of DSBs [30].
• Experiments were designed to examine in vivo changes in total transcription and in the expression of the c-fos gene following whole-body exposure of mice to JANUS fission-spectrum neutrons [31].
• Radiation repair-deficient (wst/wst) and -proficient (wst/., C57BL/6 x C3H F1) mice were exposed to JANUS fission-spectrum neutrons calibrated to deliver a gut dose of 50 cGy [31].

Analytical, diagnostic and therapeutic context of Neutrons

• Twelve hours after treatment with Ara-C, B6CF1/ANL mice were exposed to increasing single doses of either 137Cs gamma-rays or neutrons from the Fermilab accelerator, or a split dose of neutrons with intervals of 1, 2, and 3 hours [32].
• No studies using neutrons or combined hormonal therapy with surgery or radiotherapy were identified in which patients were stratified by pretreatment PSA [33].
• The RBE values, as measured by the comet assay, were 6.3, 5.4, 4.7, 4.3, 2.6, and 1.7 for 0.37, 0.57, 0.79, 0.186, 1, and 2.3 MeV neutrons [34].
• The success of the initial diffraction experiments with D-xylose isomerase demonstrate the power of spallation neutrons for protein crystallography and should provide further impetus for neutron diffraction studies of biologically active and significant proteins [35].
• The ability of WR-2721 to protect mice against two modes of death following whole-body radiation with 137Cs gamma rays or d(22)+Be neutrons was examined [36].

References