Biochemistry spotters case studies visuals and graphs

1. Biochemistry Spotters
 Case studies
 Visuals
 Spot Questions
 Graphs
Biochemistry for Medics
www.namrata.co
10/28/2012 Biochemistry For Medics 1

2. Make a Diagnosis
 A 29 year- old officer presented to emergency department
complaining of chills and breathing difficulty.
 He was a heroin abuser who was admitted in the same
hospital 7 years ago because of drug over dosage.
 He had lost 10 kg of body weight since his last clinical
visit.
 On examination, he had multiple enlarged lymph nodes.
Several red nodules were present on the skin of chest and
arms.
The chest radiograph showed diffuse pneumonia.
 Sputum smear revealed numerous Pneumocystis
organisms.
Skin biopsy revealed Kaposi’s sarcoma as shown in the
picture
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3. Diagnosis
This is a case of HIV infection. History of drug
abuse, weight loss, typical presence of
lymphadenopathy and AIDS markers- Kaposi
sarcoma and Pneumocystis pneumonia signify HIV
infection.
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4. Identify the structure and mention any
two of its important uses
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5. Answer
It is Liposome, used for-
1) Drug delivery and
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2) Gene therapyBiochemistry For Medics 5

6. Identify the Protein and mention any two of its
important functions
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7. Answer
 It is a structure of collagen.
 Collagen is rich in glycine,
proline and hydroxy proline
amino acids as shown in the
figure.
 It is mostly found in tendons,
ligaments and skin, and is also
abundant in cornea, cartilage,
bone, blood vessels, the gut, and
intervertebral disc.
 The fibroblast is the most
common cell which creates
collagen.
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8. Make a Diagnosis
A 16-year-old African American girl was admitted
to the emergency room with complaints of fever
and recurrent pain in her arms and legs
Her laboratory tests revealed the following:
Hemoglobin 8.0 g/dl
Haemtocrit 9.1%
Serum Iron- 11μg/dl
Serum Albumin 4.4g/dl
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9. Make a Diagnosis
Blood Smear showed target cells, poikilocytes,
hypochromasia, sickle red cells, nucleated RBCs, and Howell-
Jolly bodies
Hb Electrophoresis -showed a slow moving band.
What is the most probable diagnosis?
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10. Answer
The patient is suffering from sickle cell anemia
The Sickle cell disease, also called as sickle cell
anemia is due to a single nucleotide alteration
(point mutation) in the β globin gene of
hemoglobin resulting in rigid misshapen
erythrocytes- sickle shaped erythrocytes.
Such sickled cells frequently block the flow of
blood in the narrow capillaries. The interruption in
the supply of oxygen leads to tissue anoxia, causing
pain and eventually death of cells (infarction) in the
vicinity of blockage.
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11. Make a Diagnosis
A 12 –year-old girl has been brought by her
parents for consultation. She has pale skin,
blonde hair and pink iris. She is otherwise
healthy, but is unable to fix the gaze.
Parents reveal that their first two children,
a boy and a girl, had similar symptoms, but
the parents themselves are normal.
What is the most probable diagnosis?
10/28/2012 Biochemistry For Medics 11

12. Make a Diagnosis
Normal parents having two affected children, male and female, is
suggestive of Autosomal recessive inheritance of oculo-cutaneous
albinism. The baby has defect in the synthesis of melanin . Pale skin,
blonde hair and pink color of iris, are all due to the absence of
melanin. The visual impairment is also typical of albinism.
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13. Make a Diagnosis
A 3-year-old child has been brought to the clinic because of
excessive exhaustion and fatigue. On further questioning of the
mother, she reports that she was previously breastfeeding but
had to stop to return to work. To feed all of her other children,
she had to dilute her formula with water to make the formula
last longer for the entire family.
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14. Make a Diagnosis
The child is irritable, has starved appearance, weight is
much below for height, mid-arm muscle circumference
is 12 cm and triceps thickness is 2mm.
The creatinine-height index (the 24-h urinary creatinine
excretion compared with normal values based on
height) is low but serum Albumin is normal.
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15. Answer
The child is suffering from Nutritional Marasmus.
 Marasmus is a state in which virtually all available
body fat stores are exhausted due to starvation.
The given patient has starved appearance diagnostic
of Marasmus.
The low body weight, diminished skin-fold thickness
and reduced arm muscle circumference reflect the loss
of fat reserves and the catabolism of proteins
throughout the body.
 The low creatinine-height index also reflects the loss
of muscle mass while the normal serum albumin
differentiates it from Kwashiorkor which is primarily
due to protein deficiency.
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16. Spot Question
A 60- year- old woman presents with chest pain
radiating to her left arm. She is diagnosed with having
had a myocardial infarct and is prescribed a statin
medication. Statin is known as a Hypolipidemic drug.
What is the mechanism of action of this drug ?
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17. Answer
The Statins act as competitive inhibitors of the
enzyme HMG-CoA reductase, the rate limiting
enzyme of the pathway of cholesterol
biosynthesis.
Lovastatin is a member of a class of drugs
(Atorvastatin, fluvastatin, pravastatin and
Simvastatin are others in this class) called statins
that are used to treat hypercholesterolemia.
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18. Make a diagnosis
An 11-year-old girl has been brought by her
parents to the accident & emergency
department in a confused state with
symptoms of acute abdomen, respiratory
difficulty & acetone-like smell of breath. She
is a known case of Type 1 Diabetes Mellitus
but is non compliant to insulin therapy.
What is the likely diagnosis?
What is the expected outcome of urine
analysis ?
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19. Answer
The girl is suffering from Diabetic ketoacidosis, the
most frequent complication of Type 1 DM.
Urine analysis is expected to reveal the presence of
glucose and ketone bodies while blood biochemistry
would reveal, hyperglycemia, metabolic acidosis, and
volume depletion due to osmotic diuresis.
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20. Spot Question
The above Line weaver-Burk plot shows the mechanism of action of a
drug used for the treatment of gout. The said drug acts by inhibiting
xanthine oxidase enzyme.
Which type of inhibition is shown in the graph?
Name a similarly acting drug used for the treatment of
10/28/2012
hypertension. Biochemistry For Medics 20

21. Answer
Since the Km has increased and Vmax is constant , it is
competitive inhibition. Allopurinol acts by inhibiting Xanthine
oxidase enzyme.
Captopril, an antihypertensive drug acts similarly to
competitively inhibit, Angiotensin Converting Enzyme (ACE).
10/28/2012 Biochemistry For Medics 21

22. Make a diagnosis
A 24- year- old patient was brought to
medical OPD with acute abdominal pain,
depression and extreme weakness.
Urine analysis revealed purple color and
the presence of ALA and PBG (Delta amino
Levulinic acid and Porphobilinogen).
What is the probable diagnosis and defect
in this disease ?
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23. Answer
It is a case of Acute
intermittent Porphyria.
 Purple colored urine,
presence of ALA (Delta
amino levuliinic acid) and
PBG (Porphobilinogen)
and
 Psychiatric symptoms
are diagnostic of Acute
intermittent Porphyria.
There is deficiency of
PBG deaminase enzyme
(Porphobilinogen
deaminase)
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24. Spot Question
State at least 2 metabolic complications of obesity and give the
reason for obesity upon excessive carbohydrate consumption.
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25. Obesity Obesity is associated
with hypertension,
dyslipidemia, insulin
resistance, diabetes
mellitus, IHD and gall
bladder disease.
Excessive carbohydrate
consumption provides
glycerol and Acetyl co A
through formation of
Pyruvate from Glucose
and NADPH through
HMP pathway. This
helps in fatty acid
biosynthesis and more
formation of
10/28/2012 Biochemistry For Medics triglycerides. 25

26. Spot Question
Name two chief nutrients of milk and state the
reason for milk intolerance in certain individuals.
10/28/2012 Biochemistry For Medics 26

27. Answer
The important
components of milk are
lactose as milk sugar,
casein, lactalbumin and
lactglobulins as milk
proteins. The average
distribution of
nutrients is- 87.7%
water, 4.9% lactose
(carbohydrate), 3.4%
fat, 3.3% protein, and
0.7% minerals.
Milk intolerance (Lactose intolerance) occurs due to deficiency of
lactase enzyme, there is inability to digest lactose and the
10/28/2012 associated symptoms are due to accumulated lactose .
Biochemistry For Medics 27

28. Spot Question
Based on the findings in the peripheral blood film, the patient
has been diagnosed with megaloblastic anemia. Name at least
two vitamins known to cause megaloblastic anemia
10/28/2012 Biochemistry For Medics 28

29. Answer
 Megaloblastic anemia is observed in vitamin B12 and
folic acid deficiencies.
Macrocytes are observed and some of the red blood
cells show ovalocytosis. A 6-lobed polymorph nuclear
leucocyte is present.
 Oval macrocytes, usually with considerable
anisocytosis and poikilocytosis, are the main feature.
 The MCV is usually >100 fL unless a cause of
microcytosis (e.g., iron deficiency or thalassemia trait) is
present.
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30. Make a diagnosis
A 1-year-old girl is brought to her
pediatrician’s office with concerns about
her development. She had an
uncomplicated birth.
The mother reports that the baby is not
achieving the normal milestones for a baby
of her age.
She also reports an unusual odor to her
urine and some areas of hypo pigmentation
on her skin and hair.
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31. Make a diagnosis
On exam, the girl is noted to have some muscle
hypotonia and microcephaly. The urine collected is
found to have a “mousy” odor.
What is the most likely diagnosis?
What is the biochemical basis of the hypo
pigmented skin and hair?
10/28/2012 Biochemistry For Medics 31

32. Answer
Likely diagnosis-
Phenyl ketonuria
Biochemical defect-
Deficiency of phenyl
alanine hydroxylase
Biochemical basis
of
hypopigmentation:
Phenylalanine is
competitive
inhibitor of
tyrosinase (key
enzyme in melanin
synthesis)
10/28/2012 Biochemistry For Medics 32

33. Spot Question
 A 37-year-old female presents to your clinic to
discuss her plans for a new vegetarian diet.
The patient heard from a friend about a new
vegetarian diet that promised rapid weight loss.
The diet consists of many leafy vegetables with
no pork, chicken, beef, eggs, or milk.
 She is also planning on working out regularly
with the goal of running a marathon within the
year.
 After listening to the patient, you refer her to a
nutritionist for further assistance and guidance
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34. Spot Question
What is an essential amino acid, and how many
are there? List the essential amino acids.
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Biochemistry For Medics

35. Answer
Essential amino acids: The amino acids that cannot
be synthesized by the body. There are a total of ten
essential amino acids.
List of essential amino acids: Isoleucine, leucine,
lysine, Methionine, Phenylalanine, Threonine,
Tryptophan, and Valine
Histidine and Arginine are semi essential amino
acids, that can be synthesized but their demand
increases during growth, repair and reproduction.
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