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51.
Sitaraman BalajiSubramanian Krishnamoorthy Sathiya Karunakaran Balaji Moorthi Thirunavukarasu Surparaju Phanikiran Mohamed Rela 《Reports of Practical Oncology and Radiotherapy》2021,26(6):1060
Modern radiotherapy machines with refinements in planning software and image-guidance apparatuses have made stereotactic body radiotherapy (SBRT) more widely available as an effective tool in the management of spine metastases. In conventional palliative radiotherapy, the aim has traditionally been pain relief and short-term local control. In contrast, SBRT aims to deliver an ablative dose to enhance local control, with a smaller number of fractions while sparing the organs at risk (OAR), especially the spinal cord. Recently, trials have asserted the role of spine SBRT as an effective modality for durable local control, in addition to achieving pain relief. The quality of evidence for spine SBRT data is maturing, while prospective published trials on re-irradiation SBRT in spine remain sparse. The purpose of the present case report is to share the challenges faced while salvaging a dorsal spine metastasis and ablating a new right adrenal metastatic lesion in proximity of the transplanted liver. 相似文献
52.
对赤峰兴隆沟遗址第一地点出土的人类椎骨上椎体的退行性关节病(DJD)和黄韧带骨化(OLF)进行了生物考古学研究,制订了这两种病症患病程度的分级记录标准,并对患病率和患病程度均值进行了统计分析。对两性的对比发现DJD的差异主要体现在男性颈椎患病较多而女性腰椎患病较多,OLF的主要差异则是男性胸椎患病率显著高于女性。通过与对比组的比较,发现兴隆沟组腰椎、颈椎DJD患病率相对较高,并再次验证了两性患病情况存在的明显差异;兴隆沟组OLF患病率与对比组也有显著差异。兴隆沟组的椎骨患病情况不一定与生业模式有关,只反映了脊柱承受负荷的情况,其差异暗示行为模式上的差异。建议开展其他方面研究以详细了解其行为模式,同时要重视建立统一的古病理研究标准的重要性。 相似文献
53.
Martina Hrušková-Martišová Stano Pekár Alexandr Gromov 《Journal of Insect Behavior》2008,21(5):440-449
Stridulation in solifuges has not been investigated yet. We performed a comparative analysis of the stridulatory organs and
sounds produced by juveniles of various developmental stages and adults (both sexes) of Galeodes caspius subfuscus Birula. The stridulatory organ is of similar morphology in all developmental stages. The sound that they produced was a broad
frequency hissing, composed of one or two chirps with maximum at 2.4 kHz. The intensity of the sound was found to increase
with body size. Otherwise, no differences were observed between stridulation in juvenile, male and female individuals. Therefore,
we suggest that the stridulation in solifuges has primarily a defensive role. As solifuges are neither venomous nor unpalatable,
they might imitate an accoustically aposematic organism that shares the same habitat and has similar circadian activity, e.g.
vipers. It may also have an intraspecific function in reduction of cannibalistic tendencies. 相似文献
54.
Karam Kim Jinhee Yang Xiao‐Ping Zhong Myoung‐Hwan Kim Yun Sook Kim Hyun Woo Lee Seungnam Han Jeonghoon Choi Kihoon Han Jinsoo Seo Stephen M Prescott Matthew K Topham Yong Chul Bae Gary Koretzky Se‐Young Choi Eunjoon Kim 《The EMBO journal》2009,28(8):1170-1179
Diacylglycerol (DAG) is an important lipid signalling molecule that exerts an effect on various effector proteins including protein kinase C. A main mechanism for DAG removal is to convert it to phosphatidic acid (PA) by DAG kinases (DGKs). However, it is not well understood how DGKs are targeted to specific subcellular sites and tightly regulates DAG levels. The neuronal synapse is a prominent site of DAG production. Here, we show that DGKζ is targeted to excitatory synapses through its direct interaction with the postsynaptic PDZ scaffold PSD‐95. Overexpression of DGKζ in cultured neurons increases the number of dendritic spines, which receive the majority of excitatory synaptic inputs, in a manner requiring its catalytic activity and PSD‐95 binding. Conversely, DGKζ knockdown reduces spine density. Mice deficient in DGKζ expression show reduced spine density and excitatory synaptic transmission. Time‐lapse imaging indicates that DGKζ is required for spine maintenance but not formation. We propose that PSD‐95 targets DGKζ to synaptic DAG‐producing receptors to tightly couple synaptic DAG production to its conversion to PA for the maintenance of spine density. 相似文献
55.
Dendritic spines are small, mushroom-like protrusions from the arbor of a neuron in the central nervous system. Interdependent
changes in the morphology, biochemistry, and activity of spines have been associated with learning and memory. Moreover, post-mortem
cortices from patients with Alzheimer’s or Parkinson’s disease exhibit biochemical and physical alterations within their dendritic
arbors and a reduction in the number of dendritic spines. For over a decade, experimentalists have observed perforations in
postsynaptic densities on dendritic spines after induction of long-term potentiation, a sustained enhancement of response
to a brief electrical or chemical stimulus, associated with learning and memory. In more recent work, some suggest that activity-dependent
intraspine calcium may regulate the surface area of the spine head, and reorganization of postsynaptic densities on the surface.
In this paper, we develop a model of a dendritic spine with the ability to partition its transmission and receptor zones,
as well as the entire spine head. Simulations are initially performed with fixed parameters for morphology to study electrical
properties and identify parameters that increase efficacy of the synaptic connection. Equations are then introduced to incorporate
calcium as a second messenger in regulating continuous changes in morphology. In the model, activity affects compartmental
calcium, which regulates spine head morphology. Conversely, spine head morphology affects the level of local activity, whether
the spines are modeled with passive membrane properties, or excitable membrane using Hodgkin–Huxley kinetics. Results indicate
that merely separating the postsynaptic receptors on the surface of the spine may add to the diversity of circuitry, but does
not change the efficacy of the synapse. However, when the surface area of the spine is a dynamic variable, efficacy of the
synapse may vary continuously over time. 相似文献
56.
Michael Marina Kathrin Ulrich Alexander Martin Christoph 《Journal of electromyography and kinesiology》2009,19(5):e353-e361
The aim of this study was to investigate the cervicocephalic kinaesthesia of healthy subjects for gender and age effects and its reliability in a new virtual reality test procedure. 57 healthy subjects (30 male, 27 females; 18-64 years) were immersed into a virtual 3D scene via a headmounted display, which generated specific head movements. The joint repositioning error was determined in a static and dynamic test at the times T0, T1 (T0 + 10 minutes) and T2 (T0 + 24 hours). The intrasession reliability (T0-T1) and the intersession reliability (T0-T2) were analysed. In both tests no gender- or age-specific effects were found. In the overall group the means of the static test were 6.2°-6.9° and of the dynamic test were 4.5°-4.9°. The intratest difference in the static test was -0.16° and the intertest difference was 0.47°. The intratest difference in the dynamic test was 0.42° and the intertest difference was 0.37°. The static and dynamic test was reproducible in healthy subjects, with minor deviations, irrespective of gender and age. The smaller interindividual differences in the dynamic test could be beneficial in the comparison of healthy individuals and individuals with cervical spine disorders. 相似文献
57.
青海湖裸鲤生长特征的研究 总被引:13,自引:1,他引:12
对2002年5月—2003年7月采自青海湖的1174尾青海湖裸鲤样本年龄进行了耳石鉴定,并依据年龄推算了生长率。青海湖裸鲤体长与体重的关系为:W=0.000174×L2.4990(♀)、W=0.0000402×L2.7538(♂),雌、雄个体生长差异显著。其体长Von Bertalanffy生长方程为:Lt=551.9301(1-e-0.0711(t 0.3044))(♀),Lt=682.8688(1-e-0.0530(t 0.4240))(♂);体重Von Bertalanffy生长方程为:Wt=1237.3431(1-e-0.0711(t 0.3044))2.4990(♀),Wt=2567.3242×(1-e-0.0530(t 0.4240))2.7538(♂)。其雌、雄生长拐点分别为12.57龄和18.67龄。 相似文献
58.
59.
Climate change alters the reproductive phenology and investment of a lacustrine fish,the three‐spine stickleback 下载免费PDF全文
High‐latitude lakes are particularly sensitive to the effects of global climate change, demonstrating earlier ice breakup, longer ice‐free seasons, and increased water temperatures. Such physical changes have implications for diverse life‐history traits in taxa across entire lake food webs. Here, we use a five‐decade time series from an Alaskan lake to explore effects of climate change on growth and reproduction of a widely distributed lacustrine fish, the three‐spine stickleback (Gasterosteus aculeatus). We used multivariate autoregressive state‐space (MARSS) models to describe trends in the mean length for multiple size classes and to explore the influence of physical (date of ice breakup, surface water temperature) and biological (density of con‐ and heterospecifics) factors. As predicted, mean size of age 1 and older fish at the end of the growing season increased across years with earlier ice breakup and warmer temperatures. In contrast, mean size of age 0 fish decreased over time. Overall, lower fish density and warmer water temperatures were associated with larger size for all cohorts. Earlier ice breakup was associated with larger size for age 1 and older fish but, paradoxically, with smaller size of age 0 fish. To explore this latter result, we used mixing models on age 0 size distributions, which revealed an additional cohort in years with early ice breakup, lowering the mean size of age 0 fish. Moreover, early ice breakup was associated with earlier breeding, evidenced by earlier capture of age 0 fish. Our results suggest that early ice breakup altered both timing and frequency of breeding; three‐spine stickleback spawned earlier and more often in response to earlier ice breakup date. While previous studies have shown the influence of changing conditions in northern lakes on breeding timing and growth, this is the first to document increased breeding frequency, highlighting another pathway by which climate change can alter the ecology of northern lakes. 相似文献
60.