问题 问答题 简答题

简述室管膜瘤的临床特点。

答案

参考答案:

好发于儿童及青年,约占胶质瘤的12%,由脑室壁上的室管膜细胞发生,突出于脑室系统内,多见于侧脑室、第四脑室底部及第三脑室,偶见于脊髓的中央管,可穿过脑室壁侵入脑实质,可经第四脑室的正中孔或侧孔长入小脑延髓池及桥池内。肿瘤与周围脑组织分界尚清楚,有时有假囊形成,本瘤亦有种植性转移倾向。

填空题
单项选择题

Almost every day the media discovers an African American community fighting some form of environmental threat from land fills, garbage dumps, petrochemical plants, refineries, bus depots, and the list goes on. For years, residents watched helplessly as their communities became dumping grounds.
But citizens didn’t remain silent for long. Local activists have been organizing under the mantie of environmental justice since as far back as 1968. More than three decades ago, the concept of environmental justice had not registered on the radar screens of many environmental or civil rights groups. But environmental justice fits squarely under the civil rights umbrella. It should not be forgotten that Dr. Martin Luther King Jr. went to Memphis on an environmental and economic justice mission in 1968, seeking support for striking garbage workers who were underpaid and whose basic duties exposed them to environmentally hazardous conditions.
In 1979, a landmark environmental discrimination lawsuit filed in Houston, followed by similar litigation efforts in the 1980s, rallied activists to stand up to corporations and demand government intervention.
In 1991, a new breed of environmental activists gathered in Washington, D.C. , to bring national attention to pollution problems threatening low-income and minority communities. Leaders introduced the concept of environmental justice, protesting that Black, poor and working-class communities often received less environmental protection than White or more affluent communities. The first National People of Color Environmental Leadership Summit effectively broadened what "the environment" was understood to mean. It expanded the definition to include where we live, work, play, worship and go to school, as well as the physical and natural world. In the process, the environmental justice movement changed the way environmentalism is practiced in the United States and, ultimately, worldwide.
Because many issues identified at the inaugural summit remain unaddressed, the second National People of Color Environmental Leadership Summit was convened in Washington, D.C. , this past October. The second summit was planned for 500 delegates ; but more than 1,400 people attended the four-day gathering.
"We are pleased that the Summit Ⅱ was able to attract a record number of grassroots activists, academicians, students, researchers, planners, policy analysts and government officials. We proved to the world that our movement is alive and well, and growing," says Beverly Wright, chair of the summit. The meeting produced two dozen policy papers that show powerful environmental and health disparities between people of color and Whites.

In Paragraph 1, the word "residents" refers to ______ in particular.

A.ethnic groups in the U.S.

B.the American general public

C.African Americans

D.the U.S. working-class