TABLE 1-149 Physiologic Characteristics of the Various Forms of Shock 2 page

1-166. The answer is A (Chap. 276) This patient presents with symptoms of spinal cord compression in the setting of known stage IV breast cancer. This represents an oncologic emergency because only 10% of patients presenting with paraplegia regain the ability to walk. Most commonly, patients develop symptoms of localized back pain and tenderness days to months before developing paraplegia. The pain is worsened by movement, cough, or sneezing. In contrast to radicular pain, the pain related to spinal cord metastases is worse with lying down. Patients presenting with back pain alone should have a careful examination to attempt to localize the lesion before development of more severe neurologic symptoms. In this patient with paraplegia, there is an definitive level at which sensation is diminished. This level is typically one to two vertebrae below the site of compression. Other findings include spasticity, weakness, and increased deep tendon reflexes. In those with autonomic dysfunction, bowel and bladder incontinence occur with decreased anal tone, absence of the anal wink and

bulbocavernosus reflexes, and bladder distention. The most important initial step is the administration of high-dose intravenous corticosteroids to minimize associated swelling around the lesion and prevent paraplegia while allowing further evaluation and treatment. MRI should be performed of the entire spinal cord to evaluate for other metastatic disease that may require therapy. Although a brain MRI may be indicated in the future to evaluate for brain metastases, it is not required in the initial evaluation because the bilateral nature of the patient's symptoms and sensory level clearly indicate the spinal cord as the site of the injury. After an MRI has been performed, a definitive treatment plan can be made. Most commonly, radiation therapy is used with or without surgical decompression.

1-167 and 1-168. The answers are В and E, respectively.(Chap. 276) Tumor lysis syndrome occurs most commonly in individuals undergoing chemotherapy for rapidly proliferating malignancies, including acute leukemias and Burkitt's lymphoma. In rare instances, it can be seen in chronic lymphoma or solid tumors. As the chemotherapeutic agents act on these cells, there is massive tumor lysis that results in release of intracellular ions and nucleic acids. This leads to a characteristic metabolic syndrome of hyperuricemia, hyper-phosphatemia, hyperkalemia, and hypocalcemia. Acute kidney injury is frequent and can lead to renal failure, requiring hemodialysis if uric acid crystallizes within the renal tubules. Lactic acidosis and dehydration increase the risk of acute kidney injury. Hyper-phosphatemia occurs because of the release of intracellular phosphate ions and causes a reciprocal reduction in serum calcium This hypocalcemia can be profound, leading to neuromuscular irritability and tetany Hyperkalemia can become rapidly life threatening and cause ventricular arrhythmia.

Knowing the characteristics of tumor lysis syndrome, one can attempt to prevent the known complications from occurring. It is important to monitor serum electrolytes very frequently during treatment. Laboratory studies should be obtained no less than three times daily, but more frequent monitoring is often needed. Allopurinol should be administered prophylactically at high doses. If allopurinol fails to control uric acid to less than 8 mg/dL, rasburicase, a recombinant urate oxidase, can be added at a dose of 0.2 mg/kg. Throughout this period, the patient should be well hydrated with alkalinization of the urine to a pH of greater than 7.0. This is accomplished by administration of intravenous normal or ^lA normal saline at a dose of 3000 mL/m² daily with sodium bicarbonate. Prophylactic hemodialysis is not performed unless there is underlying renal failure before starting chemotherapy.

SECTION II Nutrition

QUESTION

DIRECTIONS: Choose the one best response to each question.

II-1. What is the optimal percentage of daily caloric intake derived from carbohydrates?

A. <25%

B. 25–35%

C. 45–55%

D. 65–75%

II-2. When considering the nutritional requirements for an individual, what term is used to define the quantitative estimated nutrient intake?

A. Adequate intake

B. Dietary reference intakes

C. Estimated average requirement

D. Recommended daily allowance

E. Tolerable upper levels of nutrient intake

II-3. The resting energy expenditure is a rough estimate of total caloric needs in a state of energy balance. Of these two patients with stable weights, which person has the highest resting energy expenditure (REE): Patient A, a 40-year-old man who weighs 90 kg and is sedentary, or Patient B, a 40-year-old man who weighs 70 kg and is very active?

A. 40-year-old man who weighs 90 kg and is sedentary

B. 40-year-old man who weighs 70 kg and is very active

C. REE is the same for both patients

D. Not enough information given to calculate the REE

II-4. A new study has been published showing a benefit of 25 mg/d of vitamin X. The recommended estimated average requirement of vitamin X is 10 mg/d, two standard deviations below the amount published in the study. The tolerable upper limit of vitamin X is unknown. Your patient wants to know if it is safe to consume 25 mg/d of vitamin X. What is the most appropriate answer?

A. Two standard deviations above the estimated average requirement defines the tolerable upper
limit.

B. 25 mg/d is probably too much vitamin X in 1 day.

C. 25 mg/d is statistically in a safe range of the estimated average requirement.

D. The study was not designed to assess safety and therefore should not influence practice.

II-5. A 36-year-old man is admitted from the emergency room with cellulitis of the right leg. He is homeless and is an alcoholic. He drinks a half-liter of vodka daily. He has no other significant medical history. Yo u are concerned about his nutritional state, as he has limited caloric intake other than alcohol. Given his alcoholism and poor oral intake, he would be at risk of deficiency of all of the following vitamins EXCEPT:

A. Folate

B. Thiamine

C. Vitamin B₁₂

D. Vitamin C

E. Vitamin E

II-6. A 62-year-old man with a long-standing history of alcoholism is brought to the emergency department after being found wandering in a park without shirt or shoes in the winter. When asked about the circumstances that led to him being in the emergency room, he initially states that some men were chasing him. When you return to the room 20 minutes later, he does not recall meeting you and states that he was kicked out of his daughter’s home without clothing. His daughter reports that he frequently seems confused and makes up stories all the time regarding his behavior. His only other complaint is a burning pain in his legs that is present at all times. He has no psychiatric history. He is college educated and worked as an accountant until his alcoholism led to the loss of his job. He typically drinks about 2 L of wine daily, but denies recent alcohol intake. On physical examination, he appears confused and oriented to name only. Vital signs are normal. Horizontal nystagmus is noted. He has a bilateral symmetric sensory neuropathy in a stocking-glove distribution. Deep tendon reflexes are depressed. His gait is widely based and ataxic. A fine resting tremor is present. His blood alcohol level is 0.02 g/dL. What is the most likely cause of the patient’s current clinical condition?

A. Acute alcohol intoxication

B. Delirium tremens

C. Lead intoxication

D. Niacin deficiency

E. Thiamine deficiency

II-7. A 48-year-old man is diagnosed with carcinoid syndrome after presenting with diarrhea, flushing, and hypotension. With treatment, he experiences an appropriate response biochemically and with most of his symptoms; however, he continues to complain of diarrhea and mouth soreness. He also remains fatigued with a loss of appetite and irritability. On examination, you notice his tongue is bright red and somewhat enlarged, and is tender to the touch. Dermatologically, he has a red scaly rash on sun-exposed areas and around his neckline. What is the most likely vitamin or mineral deficiency in this patient?

A. Copper

B. Niacin

C. Riboflavin

D. Vitamin C

E. Zinc

II-8. Vitamin A deficiency is associated with an increased risk of which of the following?

A. Blindness

B. Mortality from dysentery

C. Mortality from malaria

D. Mortality from respiratory illness

E. All of the above

II-9. A 51-year-old alcoholic man is admitted to the hospital for upper gastrointestinal bleeding. From further history and physical examination, it becomes apparent that his bleeding is from gingival membranes. He is intoxicated and complains of fatigue. Reviewing his chart you find that he had a hemarthrosis evacuated 6 months ago and has been lost to follow-up since then. He takes no medications. Laboratory data show platelets of 250,000 and INR of 0.9. He also has a diffuse hemorrhagic eruption on his legs that is centered around hair follicles. What is the recommended treatment for this patient’s underlying disorder?

A. Folate

B. Niacin

C. Thiamine

D. Vitamin C

E. Vitamin K

II-10. A 42-year-old male patient wants your opinion about vitamin E supplements. He has read that taking high doses of vitamin E can improve his sexual performance and slow the aging process. He is not vitamin E deficient. You explain to him that these claims are not based on good evidence. What other potential side effect should this patient be concerned about?

A. Deep venous thrombosis

B. Hemorrhage

C. Night blindness

D. Peripheral neuropathy

E. Retinopathy

II-11. You are seeing a pediatric patient from Djibouti in consultation who was admitted with a constellation of symptoms including diarrhea, alopecia, muscle wasting, depression, and a rash involving the face, extremities, and perineum. The child has hypogonadism and dwarfism. You astutely make the diagnosis of zinc deficiency, and laboratory tests confirm this (zinc level <70 μL/dL). What other clinical finding is this patient likely to manifest?

A. Dissecting aortic aneurysm

B. Hypochromic anemia

C. Hypoglycemia

D. Hypopigmented hair

E. Macrocytosis

II-12. When compared to kwashiorkor, which of the following statements is TRUE regarding marasmus

or cachexia?

A. A diagnosis of marasmus or cachexia requires a more aggressive approach to nutritional
replacement than kwashiorkor.

B. Individuals with marasmus or cachexia have a starved appearance, whereas those with
kwashiorkor typically appear well nourished.

C. Marasmus and cachexia are associated with a higher risk of infection and poor wound healing
compared to kwashiorkor.

D. Marasmus develops over a period of weeks, whereas kwashiorkor takes months or years to
develop.

E. The albumin level is typically less than 2.8 g/dL in marasmus, but not in kwashiorkor.

II-13. Which of the following patients would be least likely to be at high risk of nutritional depletion?

A. A 21-year-old woman with a history of anorexia nervosa in remission for 1 year with a body
mass index of 19.4 kg/m² admitted to the hospital with an asthma exacerbation

B. A previously healthy 28-year-old man admitted to the intensive care unit with third-degree burns
covering 85% of his body surface area

C. A 32-year-old man with alcoholism admitted with acute pancreatitis who has been NPO for 6
days

D. A 41-year-old woman with short gut syndrome following resection of small bowel for a
gastrointestinal stromal tumor admitted to the hospital with dehydration

E. A 55-year-old woman admitted to the hospital for right mastectomy for breast cancer who has
recently lost weight from 91 kg to 79 kg unintentionally

II-14. You are caring for a 54-year-old woman in the intensive care unit who was admitted for treatment of severe sepsis and pneumonia. You would like to initiate enteral nutrition and plan to calculate basal energy expenditure for the patient. All of the following factors are used to determine the patient’s caloric needs EXCEPT:

A. Age

B. Albumin

C. Gender

D. Height

E. Weight

II-15. A 19-year-old woman with anorexia nervosa undergoes surgery for acute appendicitis. The postoperative course is complicated by acute respiratory distress syndrome, and she remains intubated for 10 days. She develops wound dehiscence on postoperative day 10. Laboratory data show a white blood cell count of 4000/μL, hematocrit 35%, albumin 2.1 g/dL, total protein 5.8 g/dL, transferrin 54 mg/dL, and iron-binding capacity 88 mg/dL. You are considering initiating nutritional therapy on hospital day 11. Which of the following is true regarding the etiology and treatment of malnutrition in this patient?

A. She has marasmus and nutritional support should be started slowly.

B. She has kwashiorkor and nutritional support should be aggressive.

C. She has marasmic kwashiorkor, kwashiorkor predominant, and nutritional support should be
aggressive.

D. She has marasmic kwashiorkor, marasmus predominant, and nutritional support should be slow.

II-16. After being stranded alone in the mountains for 8 days, a 26-year-old hiker is brought to the hospital for evaluation of self-amputation of his right wrist. He has not had anything to eat or drink for the past 6 days. Vital signs are within normal limits. Weight is 79.5 kg, which is 1.8 kg less than he weighed 6 months ago. His wound appears clean and is not infected. Laboratory data show a creatinine of 2.5 mg/dL, blood urea nitrogen of 52 mg/dL, glucose 96 mg/dL, albumin 4.1 mg/dL, chloride 105 meq/L, and ferritin 173 ng/mL. Which of the following statements is true regarding his risk of malnourishment?

A. He has protein-calorie malnutrition due to the rate of weight loss.

B. He has protein-calorie malnutrition due to his elevated ferritin.

C. He is at risk, but a normal individual can tolerate 7 days of starvation.

D. He is not malnourished because he is not hypoglycemic after 6 days of no food or water.

II-17. A 65-year-old man is admitted for colectomy for stage III colon cancer. On the second postoperative day, he requires repeat exploratory laparotomy due to bleeding complications. It is now postoperative day 7 from the patient’s original resection, and he has had no nutrition since prior to surgery. His body mass index prior to surgery was 28.7 kg/m², and he had normal nutritional status. He is clinically stable currently, but delirious and at high aspiration risk. He has bowel sounds present, and ileostomy output is good. What is recommended at the present time for this patient?

A. Continued NPO status as 5–7 days without nutritional support is acceptable for this patient

B. Initiation of a clear liquid diet supplemented with intravenous fluids with dextrose to maintain
adequate intake

C. Placement of a central venous catheter and initiation of total parenteral nutrition

D. Placement of a nasogastric tube and initiation of enteral nutrition

E. Placement of a nasojejunal tube and initiation of enteral nutrition

II-18. All of the following statements regarding enteral feeding in critically ill patients are true EXCEPT:

A. Enteral feeding increases splanchnic blood flow.

B. Enteral feeding stimulates secretion of gastrointestinal hormones to promote trophic gut activity.

C. Enteral feeding stimulates IgA antibody release.

D. Enteral feeding decreases neuronal activity to the gut.

E. Seventy percent of nutrients utilized by the gut are directly derived from food within the lumen of
the gut.

II-19. What body mass index is likely to be lethal in males?

A. <10 kg/m²

B. 11 kg/m²

C. 13 kg/m²

D. 16 kg/m²

E. 18.5 kg/m²

II-20. A 43-year-old woman develops hemorrhagic pancreatitis with severe systemic inflammation response syndrome. She is intubated and sedated in the medical intensive care unit with acute respiratory distress syndrome, hypotension, and renal dysfunction. She has ongoing daily fevers to as high as 104.5°F (40.3°C). She is initiated on parenteral nutrition (PN) and develops hyper-glycemia as high as 500 g/dL. She also has an increasingly positive fluid balance of more than 2 L daily. What is the most appropriate approach to management of PN in the context of this patient’s hyperglycemia and fluid retention?

A. Addition of regular insulin to the PN formula

B. Limiting sodium to less than 40 meq/d

C. Limiting glucose to less than 200 g/d

D. Providing both glucose and fat to the PN mixture

E. All of the above

II-21. A 55-year-old woman with a history of diabetic gastroparesis is intubated and on mechanical ventilation after a stroke. When the patient was suctioned that morning, she coughed profusely, with thick green secretions. You are concerned about the possibility of aspiration as a cause of her worsening respiratory status. All of the following measures are useful in preventing aspiration pneumonia in an intubated patient EXCEPT:

A. Combined enteral and parenteral nutrition

B. Elevating the head of the bed to 30°

C. Feeding at a continuous rate

D. Holding feedings for gastric residuals of more than 500 mL
D. Post–ligament of Treitz feeding

II-22. All of the following statements regarding the influence of genetics on obesity are true EXCEPT:

A. Adopted children have body mass indices more similar to their biologic parents than their
adoptive parents.

B. Decreased levels of leptin and resistance to leptin are associated with the development of
obesity.

C. Heritability follows a Mendelian pattern.

D. Identical twins have more similar body mass indices when compared to dizygotic twins.

E. In humans with mutations of the ob gene, severe early-onset obesity is seen.

II-23. All of the following syndromes are associated with obesity EXCEPT:

A. Acromegaly

B. Cushing’s syndrome

C. Hypothyroidism

D. Insulinoma

E. Prader-Willi syndrome

II-24. A 34-year-old woman sees her primary care physician for counseling regarding weight loss. She gained approximately 36 kg during her first pregnancy 6 years previously and has not lost this weight. Prior to that time, she maintained a weight of 70 kg at a height of 68 in (BMI 23.6 kg/m²). Her current weight is 110 kg (BMI 36.8 kg/m²). She has no medical history other than obesity. She is taking oral contraceptive pills and does not smoke. What is the most effective strategy for weight loss in this individual?

A. A very low calorie diet (≤800 kcal/d) with a proprietary formula

B. Referral for bariatric surgery

C. A goal to attain her prepregnancy weight within 6 months

D. Initiation of an exercise plan of 150 minutes of moderate-intensity activity weekly without
changing her dietary habits

E. Decrease calorie consumption by 500–1000 kcal/d to achieve a weight loss of 0.5–1 kg per
week

II-25. A 44-year-old woman seeks evaluation for bariatric surgery. She has tried a variety of diets in the past, but failed to sustain weight loss. She is being treated for hypertension and hypercholesterolemia, and is concerned about developing diabetes mellitus if she does not lose weight. Her height is 65 in and weight is 122 kg (BMI 44.6 kg/m²). What advice would you provide her regarding the benefits and risks of bariatric surgical procedures?

A. A restrictive surgery is as effective as a restrictive-malabsorptive surgery.

B. A vertical-banded gastroplasty is the most effective restrictive surgical procedure.

C. All types of bariatric surgery are associated with micronutrient deficiencies that require lifelong
supplementation.

D. The mean weight loss following bariatric surgery is 30–35%, and 60% of individuals are able
to maintain weight loss at 6 years.

E. The mortality associated with bariatric surgery is about 2%.

II-26. A 21-year-old woman is evaluated for low body weight. The woman’s concerned mother brought her to clinic, but the patient herself states that she is comfortable with her body weight and that she would be happier if she lost an additional 2–5 kg. She had a normal childhood and development. She has always been a high-achieving student and is currently enrolled in an honors program at her university. She has been on the dean’s list each semester and will graduate with a dual degree in political science and international business in 6 months. When she enrolled in college, she had a height of 64 in and a weight of 57 kg (BMI 21.5 kg/m²). She had initially joined a sorority, but she no longer participates and states that she is more focused on her studies at this point. She is not in a romantic relationship and denies depression or anxiety. She has grown an additional inch since enrolling in college, and her current weight is 58 kg (BMI 17.5 kg/m²). She denies excessive dieting, but states that she controls her diet carefully. She reports daily exercise, stating that she runs or bikes for 60–120 minutes daily, and she feels this is an important stress release for her. She reports a normal diet and that she will occasionally eat an entire pizza or quart of ice cream when stressed. She denies purging. She cannot recall when her last menstrual period occurred, but states that these have been irregular throughout her life. On physical examination, the patient is wearing a sweater despite the outdoor temperature being more than 80°F. Her vital signs are BP 95/60, HR 58 bpm, RR 16/min, and oxygen

saturation 99% on room air, and she is afebrile. She has salivary gland enlargement and soft, downy hair on her arms and chest. What is the most likely diagnosis?

A. Anorexia nervosa

B. Binge eating disorder

C. Bulimia nervosa

D. Hyperthyroidism

E. Patient is healthy and without a diagnosable medical condition

II-27. The patient in question II-26 undergoes an extensive laboratory evaluation prior to treatment. Her basic metabolic panel shows sodium of 132 meq/L, potassium 3.1 meq/L, chloride 94 meq/L, bicarbonate 28 meq/L, BUN 24 mg/dL, and creatinine 1.2 mg/dL. She also has an endocrine workup, which demonstrates a TSH of 0.4 μIU/mL, T₃ 42 ng/mL, T₄ 5.0 ng/mL, free T₄ 0.8 ng/dL, and serum

cortisol at 0800 of 28 μg/dL. Bone densitometry has a T-score of -2.7 at the hip and lumbar spine. What is the most appropriate treatment for this patient?

A. Alendronate 70 mg weekly plus combined estrogen/progesterone oral contraceptive pills

B. Doxepin 75 mg daily

C. Levothyroxine 50 μg daily

D. Psychological evaluation and treatment combined with supervised meals

E. All of the above

II-28. Which characteristic is more common in binge eating disorder than bulimia nervosa?

A. Frequent loss of control while eating, leading to consumption of large amounts of food in a short
period of time

B. Higher prevalence in men compared to women

C. Obesity

D. Presence of menstrual cycle

E. Self-induced vomiting

II-29. You diagnose anorexia nervosa in one of your new clinic patients. When coordinating a treatment program with the psychiatrist, what characteristics would prompt consideration for inpatient treatment instead of scheduling an outpatient assessment?

A. Amenorrhea

B. Exaggeration of food intake

C. Irrational fear of gaining weight

D. Purging behavior

E. Weight <75% of expected body weight

II-30. You are counseling a patient who is recovering from long-standing anorexia nervosa (AN). She is a 22-year-old woman who suffered the effects of AN for 8 years with a nadir body mass index of 17 kg/m² and many laboratory abnormalities during that time. What characteristic of AN is least likely to improve despite successful lasting treatment of the disorder?

A. Amenorrhea

B. Delayed gastric emptying

C. Lanugo

D. Low bone mass

E. Salivary gland enlargement

II-31. An 80-year-old woman is evaluated for a complaint of involuntary weight loss. Her baseline weight at her clinic visit 6 months ago was 67 kg. She reports that her appetite began to decrease about 2 months ago when she noticed that food no longer had the same taste. Her daughter accompanies her to the visit and reports that her mother seems increasingly listless and withdrawn. Her daughter also notes that her mother seems more forgetful, and her home has become disorganized. The patient has a history of hypertension and peripheral vascular disease. She had a transient ischemic attack 6 years ago, but has never had a stroke. There have been no recent changes to any medications. Her weight in the clinic today is 60 kg. What is the appropriate approach for the evaluation of this patient’s weight loss?

A. Ask the patient to return to the clinic in 1 month for repeat weight evaluation.

B. Order thyroid function tests.

C. Perform a Mini-Mental State Examination.

D. Reassure the patient and her daughter that this degree of weight loss is not abnormal.

E. Both B and C are correct.

ANSWERS

II-1. The answer is C. (Chap. 73) Carbohydrates comprise the greatest percentage of calories in the diet as they are the major fuel source for the brain and most tissues. The brain requires 100 g/d of glucose, with the rest of the body requiring about 50 g/d of glucose. Although glucose can be derived from proteolysis or fats, carbohydrates remain the primary energy source of the body and should comprise 45–55% of the total caloric intake. Fats should comprise no more than 30% of caloric intake, and proteins typically should comprise about 15%.

II-2. The answer is B. (Chap. 73) Dietary reference intakes (DRIs) have supplanted the recommended daily allowances (RDAs) as the benchmark recommendations for determining nutrient intake in clinical practice. The RDAs outline the average intake that will meet the nutrient needs of nearly all healthy individuals of a specific age, life stage, sex, or physiologic condition. In contrast, the DRIs take a more comprehensive approach and also consider the estimated average requirement, adequate intake, and upper tolerable limit of intake. The estimated average intake is the amount of a nutrient estimated to meet the nutrient needs for half of the healthy individuals of a specific sex and age. Because this is a median value, it is generally not acceptable to set the estimated average intake as the benchmark for intake as, by definition, 50% of individuals would require more of the specific nutrient compared to this value. As stated above, the RDA is an estimated intake that would meet the nutrient needs of almost all healthy individuals and is defined as being two standard deviations above the estimated average requirement. Adequate intake is used in the place of RDAs when estimated average requirements are unable to be determined, thus preventing the calculation of an RDA. Adequate intake is determined based on observed or experimentally determined approximations of nutrient needs and is used for

infants up to 1 year old, as well as for many minerals including calcium, manganese, chromium, and fluoride, among others. The tolerable upper limit of nutrient intake is the highest level of daily nutrient intake that is unlikely to cause adverse health effects. In many cases, there are insufficient data to determine a tolerable upper limit.

П-3. The answer is B. (Chap. 73) For patients with stable weights, REE can be calculated if the gender, weight, and activity level are provided. For males, REE = 900 + Шн-, and for females, REE = 700 + 7w, where w is weight in kilograms. The REE is then adjusted for activity level by multiplying by 1.2 for sedentary, 1.4 for moderately active, and 1.8 for very active individuals. Patient A has an REE of 2160 kcal/d. Patient B has an REE of 2880 kcal/d. For a given weight, a higher level of activity increases the REE more than a 20-kg change in weight at a given level of activity.

П-4. The answer is С (Chap. 73) The estimated average requirement (EAR) is the amount of a nutrient estimated to be adequate for half of the individuals of a specific age and sex. It is not useful clinically for estimating nutritional adequacy because it is a median requirement for a group: 50% of the individuals in a group fall below the requirement and 50% fall above it. A person taking the EAR of a vitamin has a 50% risk of inadequate intake. The recommended daily allowance (RDA) is defined statistically as two standard deviations above the EAR to ensure that the needs of most individuals are met. In this case the study used a dosage of two standard deviations above the EAR, which would be the RDA. Data on the tolerable upper limit of a vitamin are usually inadequate to establish a value for the upper limit of tolerability. The absence of a published tolerable upper limit does not imply that the risks are nonexistent.

Date: 2016-04-22; view: 787