Dose-rate dependence of heat radiosensitization

The dose rate dependence of heat radiosensitization was studied using rat astrocytoma cells in culture and a clinically relevant protocol of heat dose and heat radiation sequence. Cells were treated with a minimally toxic heat dose of 43 degrees C for 30 minutes, after which they were irradiated with varying doses of radiation at dose rates ranging from 0.567 to 300 cGy/min. This heat dose substantially reduced the extrapolation number (n), but had little effect on Do of the radiation survival curve at dose rates of 50 cGy/min or greater. At dose rates less than 10 cGy/min, 43 degrees C for 30 min had little effect on n and only for the lowest dose rate studied (0.567 cGy/min) was there a significant reduction in Do (60%). The thermal enhancement ratio did not vary inversely with radiation dose rate over the dose rate range studied but, instead, was maximal at the two dose rate extremes (0.567 and 300 cGy/min). These data demonstrate that a clinically relevant heat dose enhances very low dose rate, as well as high dose rate, ionizing radiation, but suggest that little benefit is to be gained from using dose rates intermediate between conventional radiotherapeutic high dose rates or dose rates representative of interstitial implants.     

The necessity of a teacher background for school psychologists.

Studied principals' and teachers' satisfaction with the services of their respective school psychologists via a statewide survey of 160 elementary and 90 junior high schools. The survey's purpose was to determine if teacher certification and teaching experience contributed to significantly higher ratings in a number of designated skill areas. With 1 exception, no significant differences were found in teacher and principal ratings of school psychologists with and without teacher certification. When 4 school psychologist groups with varying amounts of teaching experience were compared, principal ratings of the groups produced no significant differences. Teacher ratings of the groups, however, produced significant differences in 3 of 5 skill areas. In all cases, the difference favored fewer years of teaching experience. Findings support the view that prolonged teaching experience negatively affects performance ratings and that teaching experience per se does not significantly improve performance ratings. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Common nuclear matrix proteins in rat tissues

Nuclear matrix proteins have been defined as insoluble residual proteins resulting from treatment of isolated nuclei with nucleases, detergents and high ionic strength buffers. They are considered as in part representing the proteins constituting the three-dimensional framework of the interphase nucleus. Though cell-specific nuclear matrix proteins have been differentiated from ubiquitously occurring (common) nuclear matrix proteins, the number and types of common nuclear matrix proteins have not yet been unequivocally established. In the present study nuclear matrix proteins were prepared from isolated nuclei of rat kidney, liver, lung, spleen and testes. The matrix proteins were separated by two-dimensional (2-D) electrophoresis and silver stained. Then the spot patterns were compared by computer-assisted image analysis. Composite images were derived for nuclear matrix proteins of individual tissues. Finding between 396-483 spots per tissue, a total of 964 individual spots were registered. Of these, 102 were common nuclear matrix proteins, as appearing in each of the tissue-characteristic images. The apparent molecular mass and pI data may serve for further identification of these nuclear proteins.     

Proteomics reveals acute pro-inflammatory and protective responses in rat Kupffer cells and hepatocytes after chemical initiation of liver cancer and after LPS and IL-6

Inflammation is a key event in the development of liver cancer. We studied early inflammatory responses of Kupffer cells (KCs) and hepatocyte (HC) after cancer initiation. The chemical carcinogen N-nitrosomorpholine (NNM) was used in a rat model. We applied a comprehensive analytical strategy including metabolic labeling, 2-D PAGE, LC-MS/MS-based spot identification and shotgun proteomics and thus determined the rates of synthesis of individual proteins, compared whole tissue with isolated constituent cells and performed in vivo to in vitro comparisons of NNM effects. NNM increased synthesis of overall and 138 individual proteins identified in HC and/or KC, indicating reprogramming of metabolism favoring protection, repair and replacement of cell constituents in HC and KC. Secretome analysis by 2-D PAGE and shotgun proteomics of HC revealed the induction of acute phase proteins, in case of KC of proteases, cytokines and chemokines, indicating inflammatory effects. All responses were induced rapidly, independently of signals from other cells, and closely mimicked the pro-inflammatory and protective effects of inflammation modulators LPS in KC and IL-6 in HC. In conclusion, the carcinogen NNM exerts pro-inflammatory effects in the liver, partially by direct activation of KC. The acute inflammation and its protective component will enhance formation, survival and proliferation of initiated cells and may therefore act synergistically with the genotoxic action of the carcinogen.     

铸态和热处理态Ti-6.55Al-3.41Mo-1.77Zr合金微观组织和力学性能

采用真空感应熔炼炉将成分为Ti-6.55Al-3.41Mo-1.77Zr（质量分数）的α＋β钛合金在石墨模具中浇铸成棒材。铸态棒材在700°C下热锻后,通过两种不同的热处理后,分别得到细小和粗大的层片状结构。结果表明：铸态组织的晶粒尺寸约为660μm,而锻造后样品具有细小的晶粒尺寸,约为50μm。在1050°C热处理后的α＋β钛合金具有细小的层片状结构,得到最佳的硬度、拉伸性能和耐磨性。在800°C热处理后的α＋β钛合金具有粗大的层片状结构,具有最大的抗压强度。具有细小层片状结构的热处理态α＋β钛合金的磨损率较小,而铸态α＋β钛合金由于具有粗大和不均匀的微观组织,因此磨损率较大。     

Pyostomatitis vegetans and Crohn's disease. A specific association of 2 diseases

HISTORY AND CLINICAL FINDINGS: A 27-year-old man was referred to the dermatological out-patient clinic because of inflammatory changes in the oral mucosa of unknown cause. 5 months earlier he had been diagnosed as having Crohn's disease of the terminal ileum. On both sides of the buccal mucosa there were rough erythematous vegetations and disseminated miliary abscesses, which extended to the labial gingiva and the soft palate. Further physical examination was unremarkable. INVESTIGATIONS: Several inflammatory parameters were increased: C-reactive protein 100 mg/l, erythrocyte sedimentation rate 55/88 mm, eosinophilic cationic protein 35.8 ng/ml (normal range 2.3-16 ng/ml). White cell count was normal (7,25/nl), with a lymphocytopenia of 11.9%. There was no eosinophilia. Haemoglobin was reduced to 11.6 g/dl and the platelets raised to 526/nl. Smears of the oral mucosa showed no fungal, viral or bacterial infection. Biopsy revealed leucocytic microabscesses in the epithelium, granulation tissue and flat ulcerations with adjoining superficial necrotic zones. DIAGNOSIS, TREATMENT AND COURSE: The clinical and histological picture as well as the association with Crohn's disease (CD) suggested pyostomatitis vegetans (PV). The PV was treated with disinfectant mouth washes which improved the subjective findings. Budesonide was given for CD. CONCLUSION: PV is a rare and usually isolated condition, but it can also occur in association with a chronic gastrointestinal disease such as ulcerative colitis and Crohn's disease. The diagnosis of PV indicates a thorough gastroenterological investigation.     

Characterization of a diamine exporter in Chinese hamster ovary cells and identification of specific polyamine substrates

Export of the diamine putrescine was studied using inside-out plasma membrane vesicles prepared from Chinese hamster cells. Putrescine uptake into vesicles was a saturable and an ATP- and antizyme-independent process. Excess amounts of a series of diamines or monoacetyl spermidine, but not monoacetyl putrescine, spermidine, or spermine, inhibited putrescine transport. Putrescine uptake into vesicles prepared at pH 7.4 was suppressed at pH 5, compared with pH 7.4; was stimulated approximately 2.5-fold at pH 7.4 in vesicles prepared at pH 6.25, compared with vesicles prepared at pH 7.4; and was not inhibited by valinomycin in the presence of potassium ions. Reserpine and verapamil blocked [3H]putrescine uptake into inverted vesicles. Verapamil treatment caused an increase in intracellular contents of putrescine, cadaverine, and N8-acetylspermidine, in unstressed proliferating cells, or of N1-acetylspermidine, in cells subjected to heat shock to induce acetylation of spermidine at N1. These data indicate that putrescine export in Chinese hamster cells is mediated by a non-electrogenic antiporter capable of using protons as the counter ion. Physiological substrates for this exporter include putrescine, cadaverine, and monoacetyl spermidine and have the general structure NH3+-(CH2)n-NH2 + R at acidic or neutral pH.     

Testing logic-intensive memory ICs on memory testers

Presents Lotom, a tool which converts logic test vectors into memory test patterns and generates a corresponding memory test program for use on an economical memory tester. The authors report a sample time savings of 99% over manual conversion     

Quest for Quality in Translational Stroke Research—A New Dawn for Neuroprotection?

Despite tremendous progress in modern-day stroke therapy, ischemic stroke remains a disease associated with a high socioeconomic burden in industrialized countries. In light of demographic change, these health care costs are expected to increase even further. The current causal therapeutic treatment paradigms focus on successful thrombolysis or thrombectomy, but only a fraction of patients qualify for these recanalization therapies because of therapeutic time window restrictions or contraindications. Hence, adjuvant therapeutic concepts such as neuroprotection are urgently needed. A bench-to-bedside transfer of neuroprotective approaches under stroke conditions, however, has not been established after more than twenty years of research, albeit a great many data have demonstrated several neuroprotective drugs to be effective in preclinical stroke settings. Prominent examples of substances supported by extensive preclinical evidence but which failed clinical trials are tirilazad and disodium 2,4-sulphophenyl-N-tert-butylnitrone (NXY-059). The NXY-059 trial, for instance, was retrospectively shown to have a seriously weak study design, a trial of insufficient quality and a poor statistical analysis, although it initially met the recommendations of the STAIR committee. In light of currently ongoing novel neuroprotective stroke trials, such as ESCAPE-NA, and to avoid the mistakes made in the past, an improvement in study quality in the field of stroke neuroprotection is urgently needed. In the present review, animal models closely reflecting the “typical” stroke patient, occlusion techniques and the appropriate choice of time windows are discussed. In this context, the STAIR recommendations could provide a useful orientation. Taking all of this into account, a new dawn for neuroprotection might be possible.