238. A quiz consists of 10 multiple-choice questions, each with 5 possible answer choices (A, B, C, D, and E), one of which is correct. Suppose an unprepared student does not read the question but simply makes one random guess for each question. What is the probability that the student will get at least 3 questions correct? (Round your answer, as needed.)

Foodborne illness sickens one in six Americans each year and results in 3,000 deaths. The U.S. Department of Agriculture (USDA) calculates the cost of foodborne illnesses to be $15.6 billion annually. However, foodborne illness is preventable, and the CDC and USDA take a leading role in promotingfood safetyat the federal level.

1 Please could you explain how lymphocytes (especially B) can maintain receptors on their surfaces? Is this genetically related? If so, when the lymphocytes are first exposed to the antigens, how could the antigen receptor be synthesized? Is there a mutation within the nuclei of these lymphocytes when they learn to make the receptors? If there is, can you explain how this occurs?

2 I understand how nuclear factor-B (NFB) works in the inflammatory response but what is the mechanism by which it causes cancer?

3 What are the diseases associated with hypocomplementaemia and which complement deficiency in particular?

4 What is meant by 'B lymphocytes are sensitive to clonal deletion'?

5 What are the immunological implications of 'bare lymphocyte syndrome'/MHC deficiency?

6 Please explain oligoclonal and monoclonal.

7 I was wondering if there is any study regarding cell culture techniques of CD4 helper cells (stem cell culturing) and, if so, is it of any benefit to HIV-infected patients?

8 How do you define autoimmune disease?

9 1. Why is dexamethasone not routinely used instead of prednisolone, which is almost universally used routinely in autoimmune diseases, or other indications for steroids? Is it because dexamethasone lacks the mineralocorticoid activity seen with prednisolone and therefore does not cause salt/water retention and hypertension? 2. Can high doses of dexamethasone be used in acute relapses of multiple sclerosis (MS) in place of pulse methylprednisolone? If so, what is the recommended dosage?

10 What is meant by 'pus cell' and is this term synonymous with neutrophils?