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1.
Dr. med. Peter W. Vaupel Johannes Otte Rolf Manz 《Radiation and environmental biophysics》1982,20(4):289-300
Summary The oxyhemoglobin saturation (HbO2) of single red blood cells within tumor microvessels (diameter: 3–12 µm) of DS-Carcinosarcoma was studied using a cryophotometric micromethod. In untreated control tumors (mean tissue temperature approx. 35° C) the measured values scattered over the whole saturation range from zero to 100 sat.%, the mean being 51 sat.%. Upon heating at 40° C for 30 min, the oxygenation of the tumor tissue significantly improved as compared with control conditions. After 40° C-hyperthermia a mean oxyhemoglobin saturation of 66 sat.% was obtained. In contradistinction to this, after 43° C-hyperthermia the tumor oxygenation was significantly lower and reached a mean HbO2 saturation value of 47 sat.%. A further temperature rise to 45° C caused the oxygenation to drop drastically (mean oxyhemoglobin saturation value: 24 sat.%). This is due to a severe restriction of nutritive blood flow.The changes in tumor oxygenation after hyperthermia seem to be predominantly mediated through changes in tumor blood flow, including tumor microcirculation, which showed a similar temperature dependence. Metabolic effects probably play a minor role in the oxyhemoglobin saturation distribution within tumor microvessels.Supported by the Deutsche Forschungsgemeinschaft (Va 57/2-1). Presented in part at the International Symposium on Biomedical Thermology, June 30 to July 4, 1981, Strasbourg, France 相似文献
2.
Crickets appear to rely less upon olfactory communication than do their non-acoustical relatives, but males and females of house (Acheta) and field (Gryllus) crickets can determine sex by odour, and males can distinguish odours of conspecific and heterospecific females. In the presence of female odours, female-deprived males groom more vigorously and are more aggressive. 相似文献
3.
Marijke A. K. A. Braeken Andrew H. Kemp Tim Outhred Renée A. Otte Geert J. Y. J. Monsieur Alexander Jones Bea R. H. Van den Bergh 《PloS one》2013,8(12)
Objective
Active anxiety disorders have lasting detrimental effects on pregnant mothers and their offspring but it is unknown if historical, non-active, maternal anxiety disorders have similar effects. Anxiety-related conditions, such as reduced autonomic cardiac control, indicated by reduced heart rate variability (HRV) could persist despite disorder resolution, with long-term health implications for mothers and children. The objective in this study is to test the hypotheses that pregnant mothers with a history of, but not current anxiety and their children have low HRV, predicting anxiety-like offspring temperaments.Methods
The participants in this case-control study consist of 56 women during their first trimester and their offspring (15 male, 29 female). Women had a history of an anxiety disorder (n=22) or no psychopathology (n=34) determined using the Mini-International Neuropsychiatric Interview. The main outcome measures were indices of autonomic cardiac control including root mean square of successive differences (RMSSD) and high frequency (HF) variability. Children’s fearfulness was also assessed using the Laboratory Temperament Assessment Battery (Lab-TAB)-Locomotor Version.Results
HRV was lower in women and children in the past anxiety group compared to controls. HRV measures for mothers and children were positively correlated in the anxiety group only. In all children, low HRV measures at 2-4 months were associated with a higher chance of fearful behavior at 9-10 months.Conclusions
Pregnant women with previous but not current anxiety and their children have low HRV. Children with low HRV tend to show more fearfulness. These findings have implications for identifying children at risk of anxiety disorders and point to possible underlying mechanisms of child psychopathology. 相似文献4.
5.
6.
Brain serotonin homeostasis is crucially maintained by the serotonin transporter (5-HTT), and its down-regulation has been linked to increased vulnerability for anxiety- and depression-related behavior. Studies in 5-HTT knockout (5-HTT-/-) rodents have associated inherited reduced functional expression of 5-HTT with increased sensitivity to adverse as well as rewarding environmental stimuli, and in particular cocaine hyperresponsivity. 5-HTT down-regulation may affect normal neuronal wiring of implicated corticolimbic cerebral structures. To further our understanding of its contribution to potential alterations in basal functional and structural properties of neural network configurations, we applied resting-state functional MRI (fMRI), pharmacological MRI of cocaine-induced activation, and diffusion tensor imaging (DTI) in 5-HTT-/- rats and wild-type controls (5-HTT+/+). We found that baseline functional connectivity values and cocaine-induced neural activity within the corticolimbic network was not significantly altered in 5-HTT-/- versus 5-HTT+/+ rats. Similarly, DTI revealed mostly intact white matter structural integrity, except for a reduced fractional anisotropy in the genu of the corpus callosum of 5-HTT-/- rats. At the macroscopic level, analyses of complex graphs constructed from either functional connectivity values or structural DTI-based tractography results revealed that key properties of brain network organization were essentially similar between 5-HTT+/+ and 5-HTT-/- rats. The individual tests for differences between 5-HTT+/+ and 5-HTT-/- rats were capable of detecting significant effects ranging from 5.8% (fractional anisotropy) to 26.1% (pharmacological MRI) and 29.3% (functional connectivity). Tentatively, lower fractional anisotropy in the genu of the corpus callosum could indicate a reduced capacity for information integration across hemispheres in 5-HTT-/- rats. Overall, the comparison of 5-HTT-/- and wild-type rats suggests mostly limited effects of 5-HTT genotype on MRI-based measures of brain morphology and function. 相似文献
7.
8.
Eric van Diessen Willem M. Otte Kees P. J. Braun Cornelis J. Stam Floor E. Jansen 《PloS one》2013,8(4)
Background
Electroencephalogram (EEG) acquisition is routinely performed to support an epileptic origin of paroxysmal events in patients referred with a possible diagnosis of epilepsy. However, in children with partial epilepsies the interictal EEGs are often normal. We aimed to develop a multivariable diagnostic prediction model based on electroencephalogram functional network characteristics.Methodology/Principal Findings
Routinely performed interictal EEG recordings at first presentation of 35 children diagnosed with partial epilepsies, and of 35 children in whom the diagnosis epilepsy was excluded (control group), were used to develop the prediction model. Children with partial epilepsy were individually matched on age and gender with children from the control group. Periods of resting-state EEG, free of abnormal slowing or epileptiform activity, were selected to construct functional networks of correlated activity. We calculated multiple network characteristics previously used in functional network epilepsy studies and used these measures to build a robust, decision tree based, prediction model. Based on epileptiform EEG activity only, EEG results supported the diagnosis of with a sensitivity and specificity of 0.77 and 0.91 respectively. In contrast, the prediction model had a sensitivity of 0.96 [95% confidence interval: 0.78–1.00] and specificity of 0.95 [95% confidence interval: 0.76–1.00] in correctly differentiating patients from controls. The overall discriminative power, quantified as the area under the receiver operating characteristic curve, was 0.89, defined as an excellent model performance. The need of a multivariable network analysis to improve diagnostic accuracy was emphasized by the lack of discriminatory power using single network characteristics or EEG''s power spectral density.Conclusions/Significance
Diagnostic accuracy in children with partial epilepsy is substantially improved with a model combining functional network characteristics derived from multi-channel electroencephalogram recordings. Early and accurate diagnosis is important to start necessary treatment as soon as possible and inform patients and parents on possible risks and psychosocial aspects in relation to the diagnosis. 相似文献9.
10.
Hydroxylamine oxidation and subsequent nitrous oxide production by the heterotrophic ammonia oxidizer Alcaligenes faecalis 总被引:9,自引:0,他引:9
Nitrous oxide (N2O), a greenhouse gas, is emitted during autotrophic and heterotrophic ammonia oxidation. This emission may result from either
coupling to aerobic denitrification, or it may be formed in the oxidation of hydroxylamine (NH2OH) to nitrite (NO2
−). Therefore, the N2O production during NH2OH oxidation was studied with Alcaligenes faecalis strain TUD. Continuous cultures of A. faecalis showed increased N2O production when supplemented with increasing NH2OH concentrations. 15N-labeling experiments showed that this N2O production was not due to aerobic denitrification of NO2
−. Addition of 15N-labeled NH2OH indicated that N2O was a direct by-product of NH2OH oxidation, which was subsequently reduced to N2. These observations are sustained by the fact that NO2
− production was low (0.23 mM maximum) and did not increase significantly with increasing NH2OH concentration in the feed. The NH2OH-oxidizing capacity increased with increasing NH2OH concentrations. The apparent V
max and K
m were 31 nmol min−1 mg dry weight−1 and 1.5 mM respectively. The culture did not increase its growth yield and was not able to use NH2OH as the sole N source. A non-haem hydroxylamine oxidoreductase was partially purified from A. faecalis strain TUD. The enzyme could only use K3Fe(CN)6 as an electron acceptor and reacted with antibodies raised against the hydroxylamine oxidoreductase of Thiosphaera pantotropha.
Received: 1 September 1998 / Received revision: 5 November 1998 / Accepted: 7 November 1998 相似文献