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Updated on: 10 Oct 2019, 09:45
Originally posted by shridhar786 on 10 Oct 2019, 00:27.
Last edited by Sajjad1994 on 10 Oct 2019, 09:45, edited 2 times in total.
Last edited by Sajjad1994 on 10 Oct 2019, 09:45, edited 2 times in total.
Updated - Complete topic (908).
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Question 1
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
54% (03:18) correct
46%
(03:10) wrong
based on 563
sessions
History
Date
Time
Result
Not Attempted Yet
Question 2
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
74% (01:18) correct 26%
(01:46) wrong
based on 601
sessions
History
Date
Time
Result
Not Attempted Yet
Question 3
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
50% (01:22) correct 50%
(01:27) wrong
based on 592
sessions
History
Date
Time
Result
Not Attempted Yet
Question 4
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
76% (01:05) correct 24%
(01:24) wrong
based on 552
sessions
History
Date
Time
Result
Not Attempted Yet
New Project RC Butler 2019 - Practice 2 RC Passages Everyday
Passage # 381, Date : 10-Oct-2019
This post is a part of New Project RC Butler 2019. Click here for Details
Passage # 381, Date : 10-Oct-2019
This post is a part of New Project RC Butler 2019. Click here for Details
Myoblasts appear to be good candidates for use in gene therapy because of an unusual and advantageous biological property: when injected into muscle, they fuse with nearby muscle fibers and become an integral part of the muscle tissue. Moreover, since muscle tissue is generally well supplied with nerves and blood, the therapeutic agents produced by the transgene are also accessible to nerves and the circulatory system. Thus, myoblasts may not only be useful for treating muscle disorders such as muscular dystrophy, but also nonmuscle disorders such as neurodegenerative diseases and inherited hormone deficiencies.
In a series of experiments in rodents, a team of investigators has been testing neural stem cells as vehicles for cell-based gene therapy for brain tumors known as gliomas. Gliomas are virtually impossible to treat because the tumor cells readily invade the surrounding tissue and migrate extensively into the normal brain. The researchers genetically modified human neural stem cells to produce a protein, cytosine deaminase, that converts a nontoxic precursor drug into an active form that kills cancer cells. The engineered neural stem cells were then injected into the brains of mice with human-derived gliomas. Within two weeks of the gene therapy and systemic treatment with the precursor drug, the tumors had shrunk by 80 percent. The animal studies also revealed that neural stem cells were able to quickly and accurately "find" glioma cells, regardless of whether the stem cells were implanted directly into the tumors, implanted far from the tumors (but still within the brain), or injected into circulating blood outside the brain.
Another cell-based gene therapy system under investigation involves the use of osteoblasts. In a recent preliminary study examining a gene therapy approach to bone repair and regeneration, researchers genetically engineered osteoblasts to produce a bone growth factor. The osteoblasts were added to a biodegradable matrix that could act as a "scaffold" for new bone formation. Within a month after the cell-impregnated scaffold was implanted into mice, new bone formation was detectable. Although this work is in the very early stages, it offers hope of an effective alternative to conventional bone-grafting techniques.
In a series of experiments in rodents, a team of investigators has been testing neural stem cells as vehicles for cell-based gene therapy for brain tumors known as gliomas. Gliomas are virtually impossible to treat because the tumor cells readily invade the surrounding tissue and migrate extensively into the normal brain. The researchers genetically modified human neural stem cells to produce a protein, cytosine deaminase, that converts a nontoxic precursor drug into an active form that kills cancer cells. The engineered neural stem cells were then injected into the brains of mice with human-derived gliomas. Within two weeks of the gene therapy and systemic treatment with the precursor drug, the tumors had shrunk by 80 percent. The animal studies also revealed that neural stem cells were able to quickly and accurately "find" glioma cells, regardless of whether the stem cells were implanted directly into the tumors, implanted far from the tumors (but still within the brain), or injected into circulating blood outside the brain.
Another cell-based gene therapy system under investigation involves the use of osteoblasts. In a recent preliminary study examining a gene therapy approach to bone repair and regeneration, researchers genetically engineered osteoblasts to produce a bone growth factor. The osteoblasts were added to a biodegradable matrix that could act as a "scaffold" for new bone formation. Within a month after the cell-impregnated scaffold was implanted into mice, new bone formation was detectable. Although this work is in the very early stages, it offers hope of an effective alternative to conventional bone-grafting techniques.
1. Why does the author mention that muscle tissue is generally well supplied with nerves and blood in the second sentence of the first paragraph?
(A) to offer further proof that the advantageous biological properties of myoblasts distinguish them from osteoblasts
(B) to elaborate upon the hypothesis that myoblasts can be used to treat coronary heart disease
(C) to describe how myoblasts are able to deliver therapeutic agents for the treatment of muscular dystrophy
(D) to provide evidence that myoblasts are truly integrated into the actual fibers of a recipient muscle
(E) to explain how a transgene that binds to muscle fibers can affect — other bodily systems
(A) to offer further proof that the advantageous biological properties of myoblasts distinguish them from osteoblasts
(B) to elaborate upon the hypothesis that myoblasts can be used to treat coronary heart disease
(C) to describe how myoblasts are able to deliver therapeutic agents for the treatment of muscular dystrophy
(D) to provide evidence that myoblasts are truly integrated into the actual fibers of a recipient muscle
(E) to explain how a transgene that binds to muscle fibers can affect — other bodily systems
2. The author of this passage would most likely agree with which of the following statements?
(A) Most cell-based gene therapy systems have only been proven to work on mice and are years away from human trials.
(B) Recent research indicates that cell-based gene therapy may provide new methods of treating multiple disorders and diseases in humans.
(C) There are no gene therapy treatment methods that have been shown to be truly effective in combating gliomas.
(D) Osteoblasts, as indicated by their name, are used exclusively in the treatment of bone injuries and disorders.
(E) Nontoxic precursor drugs generally do not cause significant side effects in recipients.
(A) Most cell-based gene therapy systems have only been proven to work on mice and are years away from human trials.
(B) Recent research indicates that cell-based gene therapy may provide new methods of treating multiple disorders and diseases in humans.
(C) There are no gene therapy treatment methods that have been shown to be truly effective in combating gliomas.
(D) Osteoblasts, as indicated by their name, are used exclusively in the treatment of bone injuries and disorders.
(E) Nontoxic precursor drugs generally do not cause significant side effects in recipients.
3. The author suggests that neural stem cells exhibit which of the following traits?
I. the ability to consume gliomas
II. the ability to distribute themselves via the circulatory system
III. the ability to treat brain tumors
(A) I ONLY
(B) II ONLY
(C) I and II ONLY
(D) II and III ONLY
(E)I, II and III
I. the ability to consume gliomas
II. the ability to distribute themselves via the circulatory system
III. the ability to treat brain tumors
(A) I ONLY
(B) II ONLY
(C) I and II ONLY
(D) II and III ONLY
(E)I, II and III
4. The content of the passage leads most naturally to which of the following conclusions?
(A) Myoblast ‘scaffolding’ offers hope to patients currently facing painful bone-grafting operations.
(B) While neural stem cell research may appear promising, ethical debate surrounding it will likely hamper future applications of this new system
(C) Cytosine deaminase effectively reduces brain tumors formed by gliomas.
(D) Researchers are studying several methods of delivering cell-based gene therapy.
(E) Myoblasts offer the most promising mechanism for cell-based gene therapy.
(A) Myoblast ‘scaffolding’ offers hope to patients currently facing painful bone-grafting operations.
(B) While neural stem cell research may appear promising, ethical debate surrounding it will likely hamper future applications of this new system
(C) Cytosine deaminase effectively reduces brain tumors formed by gliomas.
(D) Researchers are studying several methods of delivering cell-based gene therapy.
(E) Myoblasts offer the most promising mechanism for cell-based gene therapy.
QUESTION- 1
The author mentions that muscle tissue is generally well supplied with nerves and blood to explain how the myoblasts, which bind to muscle fiber, can deliver therapeutic agents to other parts of the body. Since the muscles are well connected to other bodily systems, myoblasts are able to treat "nonmuscle disorders such as neurodegenerative diseases and inherited hormone deficiencies" as stated in the final sentence of paragraph one.
QUESTION- 2
While choices A, D, and E could be true, they fall outside the scope of the passage. Choice C is countered by evidence presented in the passage. Choice B summarizes the main idea of the passage. Thus, choice B is the best choice.
QUESTION- 3
The passage does not state that neural stem cells consume gliomas but rather that they can be modified to produce a protein that converts a precusor drug that in turn kills gliomas. Choice A, C, and E can be eliminated.
In the last sentence of the second paragraph, the passage states that neural stem cells can "find" gliomas in the brain even when injected into blood outside the brain. Thus, neural stem cells must have the ability to distribute via the circulatory system. Also, the first sentence of the second paragraph states that gliomas are brain tumors. Since neural stem cells can be used to treat gliomas, they are being used to treat brain tumors. Choice D is correct.
QUESTION- 4
The passage discusses three different vehicles for cell-based gene therapy. Thus, choice D is correct.
The author mentions that muscle tissue is generally well supplied with nerves and blood to explain how the myoblasts, which bind to muscle fiber, can deliver therapeutic agents to other parts of the body. Since the muscles are well connected to other bodily systems, myoblasts are able to treat "nonmuscle disorders such as neurodegenerative diseases and inherited hormone deficiencies" as stated in the final sentence of paragraph one.
QUESTION- 2
While choices A, D, and E could be true, they fall outside the scope of the passage. Choice C is countered by evidence presented in the passage. Choice B summarizes the main idea of the passage. Thus, choice B is the best choice.
QUESTION- 3
The passage does not state that neural stem cells consume gliomas but rather that they can be modified to produce a protein that converts a precusor drug that in turn kills gliomas. Choice A, C, and E can be eliminated.
In the last sentence of the second paragraph, the passage states that neural stem cells can "find" gliomas in the brain even when injected into blood outside the brain. Thus, neural stem cells must have the ability to distribute via the circulatory system. Also, the first sentence of the second paragraph states that gliomas are brain tumors. Since neural stem cells can be used to treat gliomas, they are being used to treat brain tumors. Choice D is correct.
QUESTION- 4
The passage discusses three different vehicles for cell-based gene therapy. Thus, choice D is correct.
13 Apr 2020, 01:16
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13 Apr 2020, 11:48
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Hoozan
Official Explanation
2. The author of this passage would most likely agree with which of the following statements?
Difficulty Level: 600
Explanation
While choices A, D, and E could be true, they fall outside the scope of the passage. Choice C is countered by evidence presented in the passage. Choice B summarizes the main idea of the passage. Thus, choice B is the best choice.
Answer: B
Difficulty Level: 600
Explanation
While choices A, D, and E could be true, they fall outside the scope of the passage. Choice C is countered by evidence presented in the passage. Choice B summarizes the main idea of the passage. Thus, choice B is the best choice.
Answer: B
3. The author suggests that neural stem cells exhibit which of the following traits?
Difficulty Level: 700
Explanation
The passage does not state that neural stem cells consume gliomas but rather that they can be modified to produce a protein that converts a precusor drug that in turn kills gliomas. Choice A, C, and E can be eliminated.
In the last sentence of the second paragraph, the passage states that neural stem cells can "find" gliomas in the brain even when injected into blood outside the brain. Thus, neural stem cells must have the ability to distribute via the circulatory system.
Also, the first sentence of the second paragraph states that gliomas are brain tumors. Since neural stem cells can be used to treat gliomas, they are being used to treat brain tumors.
Answer: D
Difficulty Level: 700
Explanation
The passage does not state that neural stem cells consume gliomas but rather that they can be modified to produce a protein that converts a precusor drug that in turn kills gliomas. Choice A, C, and E can be eliminated.
In the last sentence of the second paragraph, the passage states that neural stem cells can "find" gliomas in the brain even when injected into blood outside the brain. Thus, neural stem cells must have the ability to distribute via the circulatory system.
Also, the first sentence of the second paragraph states that gliomas are brain tumors. Since neural stem cells can be used to treat gliomas, they are being used to treat brain tumors.
Answer: D
