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1.
Barnett  MJ; Zussman  WV 《Radiology》1986,160(1):223-225
Granulocytic sarcoma (chloroma), a rare tumor usually associated with myelogenous leukemia, is capable of invading the meninges or brain parenchyma. Radiologic findings in a case of granulocytic sarcoma of the brain, as well as those in 11 previously reported cases of intracranial leukemic masses, are interpreted. On computed tomographic scans, the lesions can appear isodense or hyperdense, edema and necrosis are variable, and there is uniform enhancement following intravenous administration of contrast material. There may be some affinity for the posterior fossa.  相似文献   
2.
Bone strength, a key determinant of fracture risk, has been shown to display clear sexual dimorphism after puberty. We sought to determine whether sex differences in bone mass and hip bone geometry as an index of strength exist in school‐age prepubertal children and the degree to which the differences are independent of body size and lean mass. We studied 3514 children whose whole‐body and hip scans were measured using the same densitometer (GE‐Lunar iDXA) at a mean age of 6.2 years. Hip dual‐energy X‐ray absorptiometry (DXA) scans underwent hip structural analyses (HSA) with derivation of bone strength indices. Sex differences in these parameters were assessed by regression models adjusted for age, height, ethnicity, weight, and lean mass fraction (LMF). Whole‐body bone mineral density (BMD) and bone mineral content (BMC) levels were 1.3% and 4.3% higher in girls after adjustment by LMF. Independent of LMF, boys had 1.5% shorter femurs, 1.9% and 2.2% narrower shaft and femoral neck with 1.6% to 3.4% thicker cortices than girls. Consequent with this geometry configuration, girls observed 6.6% higher stresses in the medial femoral neck than boys. When considering LMF, the sexual differences on the derived bone strength indices were attenuated, suggesting that differences in muscle loads may reflect an innate disadvantage in bone strength in girls, as consequence of their lower muscular acquisition. In summary, we show that bone sexual dimorphism is already present at 6 years of age, with boys having stronger bones than girls, the relation of which is influenced by body composition and likely attributable to differential adaptation to mechanical loading. Our results support the view that early life interventions (ie, increased physical activity) targeted during the pre‐ and peripubertal stages may be of high importance, particularly in girls, because before puberty onset, muscle mass is strongly associated with bone density and geometry in children. © 2015 American Society for Bone and Mineral Research.  相似文献   
3.
Background: Cardiac opioid peptides have been identified to exert important adaptive metabolic signalling for cardioprotection against ischaemia or hypoxia‐related injury. Aims: To determine myocardial methionine‐enkephalin content in children with hypoxemic congenital heart defects and to correlate myocardial content of methionine‐enkephalin with the extent of arterial oxygen desaturation. Methods: Children (n= 20, median age of 16 months), undergoing cardiac surgical repair (tetralogy of Fallot, 17/20), were included in this study. Arterial oxygen saturation was measured on admission. Myocardial samples obtained during surgery were assayed via radioimmunochemistry for methionine‐enkephalin content. Results: Greater methionine‐enkephalin content was measured in the right ventricles of the patients suffering from recent cyanotic spells compared with those with no recent spells (cyanotic spells: 2418 ± 844 pg/g wet weight tissue, n= 6; no spells: 1175 ± 189 pg/g wet weight tissue, n= 14, P= 0.04). An inverse correlation was evident between the arterial oxygen saturation and myocardial methionine‐enkephalin content. Conclusion: Myocardial methionine‐enkephalin levels increase with the severity of hypoxic stress in congenital cardiac disease and may play an important adaptive role in countering adrenergic over‐activity and related excess demand on myocardial metabolic capacity.  相似文献   
4.
【目的】 探讨儿童牙龈炎与恒牙龋的相关关系,为儿童牙龈炎防治工作提供理论依据。 【方法】 采用多阶段分层整群随机抽样的方法共调查广州市12~13岁儿童1 115人。检查方法和标准参考1997年WHO推荐的《口腔健康调查基本方法》,牙龈炎检查六颗指数牙,龋病检查全口恒牙,分别采用牙龈指数(GI)和DMFT记录检查结果。Logistic回归分析儿童牙龈炎与恒牙龋病的关系。 【结果】 广州市12~13岁儿童牙龈炎患病率72.65%,中、重度牙龈炎患病率分别为28.16%和5.83%。恒牙龋患病率为25.83%,其中未充填龋占龋齿的73.73%。Logistic回归分析显示未充填龋是广州市12~13岁儿童牙龈炎患病的危险因素。 【结论】 广州市12~13岁儿童牙龈炎患病率较高,有未充填龋存在的儿童是广州市儿童牙龈炎重点防治人群。  相似文献   
5.

Background

High temperature and humidity conditions are associated with short-term elevations in the mortality rate in many United States cities. Previous research has quantified this relationship in an aggregate manner over large metropolitan areas, but within these areas the response may differ based on local-scale variability in climate, population characteristics, and socio-economic factors.

Methods

We compared the mortality response for 48 Zip Code Tabulation Areas (ZCTAs) comprising Philadelphia County, PA to determine if certain areas are associated with elevated risk during high heat stress conditions. A randomization test was used to identify mortality exceedances for various apparent temperature thresholds at both the city and local scale. We then sought to identify the environmental, demographic, and social factors associated with high-risk areas via principal components regression.

Results

Citywide mortality increases by 9.3% on days following those with apparent temperatures over 34°C observed at 7:00 p.m. local time. During these conditions, elevated mortality rates were found for 10 of the 48 ZCTAs concentrated in the west-central portion of the County. Factors related to high heat mortality risk included proximity to locally high surface temperatures, low socioeconomic status, high density residential zoning, and age.

Conclusions

Within the larger Philadelphia metropolitan area, there exists statistically significant fine-scale spatial variability in the mortality response to high apparent temperatures. Future heat warning systems and mitigation and intervention measures could target these high risk areas to reduce the burden of extreme weather on summertime morbidity and mortality.  相似文献   
6.
本文用 BALB/3T3 A31-1-13细胞系研究了煤尘抽提物的转化活性。亚硝化和未亚硝化的煤尘抽提物都能诱发细胞发生转化且有剂量反应关系.但亚硝化煤尘抽提物的转化活性比未亚硝化者高。从转化集落分离出来的细胞具有赘生转化的一些特征,如细胞生长迅速、接触抑制消失和停泊不依赖性生长等.本文结果看来支持煤矿工胃癌高发原因的煤尘假说。  相似文献   
7.
用鼠肝匀浆(S_9)代谢活化黄曲霉毒素B族和G族,研究它们对流感病毒在恒河猴肾细胞(LLC-MK_2)诱导干扰素-α/β的抑制作用。结果显示活化与未活化的黄曲霉毒素对干扰素诱生都有抑制作用。但代谢活化后,抑制作用增强,抑制作用的大小按B_1>G_1>B_2>G_2顺序排列,显示有结构-活性关系。而干扰素赋予细胞的抗病毒能力并不受黄曲霉毒素的影响。  相似文献   
8.
本研究旨在探讨齐墩果酸诱导人T淋巴细胞白血病Jurkat细胞株凋亡及对PTEN表达的影响。应用CCK-8法检测细胞增殖抑制率,用Hoechst33258染色观察凋亡细胞形态,Annexin V/PI双染色后流式细胞仪检测细胞凋亡,并应用实时定量RT-PCR和Western blot方法分别检测PTEN基因及其蛋白表达水平。结果表明:齐墩果酸以时间和剂量依赖方式抑制Jurkat细胞增殖,12、24和48小时的半数抑制浓度(IC50)分别约为85.35、53.66和33.18μmol/L。流式细胞术检测显示,齐墩果酸以0、40、80和160μmol/L浓度作用细胞24小时凋亡率分别为6.72%、19.8%、28.72%和30.12%(p<0.05)。80和160μmol/L齐墩果酸分别处理Jurkat细胞24小时后PTEN-mRNA及蛋白表达上调。结论:PTEN基因和蛋白表达上调可能参与齐墩果酸对Jurkat细胞的抑制增殖和诱导凋亡作用。  相似文献   
9.
Aim  General developmental outcome is known to be good in school‐aged children who experienced febrile seizures. We examined cognitive and behavioural outcomes in preschool children with febrile seizures, including language and executive functioning outcomes. Method  This work was performed in the Generation R Study, a population‐based cohort study in Rotterdam from early fetal life onwards. Information about the occurrence of febrile seizures was collected by questionnaires at the ages of 1, 2, and 3 years. At the age of 3 years, behaviour and emotion were assessed using the Child Behavior Checklist. Information on expressive language development was obtained by the Language Development Survey at the age of 2 years 6 months. To assess executive functioning, parents completed the Behaviour Rating Inventory of Executive Function – Preschool Version when their children were 4 years old. Final analyses were based on 3157 children. Results  No associations were found between febrile seizures and the risk of behavioural problems or executive functioning. In contrast to single febrile seizures, recurrent febrile seizures were significantly associated with an increased risk of delayed vocabulary development (odds ratio 3.22, [95% confidence interval 1.30–7.94]). Interpretation  Febrile seizures are not associated with problem behaviour or executive functioning in preschool children, but the results suggest that children with recurrent febrile seizures might be at risk for delayed language development.  相似文献   
10.
电子可读X线探测器的不断改进 ,使数字X线成像技术得以不断的充实和发展。自从电荷耦合技术(chargecouplede vice,CCD)的引入 ,虽使自扫描 ,直接读出数字探测器得以广泛应用 ,但随着设计的更新 ,工艺的进步 ,使具有薄膜晶体管读出机制的大范围平板探测器进入了一个新的阶段。由于X线探测器的改进 ,无论是采用固定的X线设备还是预置的图像质量都超过屏/片或光激励磷光存储计算X线摄影系统。1直接与间接转换电子X线探测器可分为直接转换和间接转换两大类。直接转换是通过探测器中的光导体如无定形硒将X线光…  相似文献   
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