Practice Test #2 Flashcards by Janae Roberts

What kind of therapy is needed for treating anaemia resulting from renal disease or from various other causes

Recombinant erythropoietin

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What is the method of administration for Recombiant erythropoietin

Subcutaneously

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How often is Recombinant erythropoietin used in treatment

three times weekly or once every 1–2 weeks or every 4 weeks

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What is the main indication for Erythropoietin therapy

End-stage renal disease (with or without dialysis)

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What is also needed in erythropoietin therapy

oral or intravenous iron

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True or False, A high serum erythropoietin level prior to treatment is valuable in predicting an e ective response

False, Low Level

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What are some common side effects for recombinant erythropoietin therapy

Side‐effects include a rise in blood pressure, thrombosis and local injection site reactions.

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What hormones are necessary for effective erythropoiesis

Androgens and thy- roxine

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What metals are needed in successive erythropoietin synthesis

iron and cobalt

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What is the dominant haemoglobin in blood after the age of 3–6 months) c

HbA

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What are the 4 polypeptide chain in Haemoglobin A

α2 β2, each with its own haem group

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What are the clinical uses of erythropoietin

Anaemia of chronic renal disease
Myelodysplastic syndrome
Anaemia associated with malignancy and chemotherapy
Anaemia of chronic diseases, e.g. rheumatoid arthritis
Anaemia of prematurity
Perioperative uses

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What is the main site for the protoporphyrin synthesis

Mitochondria

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Where is Iron supplied from for erythropoiesis

Circulating transferrin

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What synthesis occurs largely in the mitochondria

Haem

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What is the key rate‐limiting enzyme in Haem Synthesis

δ‐aminolaevulinic acid (ALA) synthase

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What is the coenzyme for Haem synthesis

Pyridoxal phosphate (vitamin B )

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The condensation of which two compounds occurs in the biochemical reaction for haem synthesis

condensation of glycine and succinyl coenzyme A

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The combination of which two compounds for Haem

Protoporphyrin combines

with iron in the ferrous (Fe2+)

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True or False the contact of α1α2 β2β1 stabilises the structure of Haemoglobin

False it is, α2β2, α1β1

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When O2 is unloaded β chains are pulled apart permitting the entry of which metabolite

2,3‐diphosphoglycerate (2,3‐DPG)

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True or False, The entry of the metabolite in the β chains results in higher affnity of the molecule for O2.

False, lower

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What is the P50 (i.e. the partial pressure of O2 at which haemoglobin is half saturated with O2) of normal blood

26.6 mmHg

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What occurs with an increased affnity for O2 in a haemoglobin oxygen (O2) dissociation curve

Curve shifts to the left

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True or False, The P50 will rise when there is an increase affinity for O2

False, it will fall

What causes the curve to shift to the right in a haemoglobin oxygen (O2) dissociation curve

Decreased affinity for O2

A rise in P50 is as result of

Decreased affinity for O2

In vivo, O2 exchange operates at ____ saturation in arterial blood

95%

in vivo, What is the mean arterial O2 tension

95mmHg

In vivo, O2 exchange operates at ____ in venous blood

70%

In vivo, What is the mean venous O2 tension

40 mmHg

The normal position of the curve depends on which 3 compound in the red cell

2,3‐DPG, H+ ions and CO2

What is the difference between normal Adult Hb and Fetal Hb

Fetal Hb is unable to bind 2,3 DPG

Rare abnormal haemoglobins associated with polycythaemia, will cause the oxygen dissociation curve to shift to which direction

Left

What is the name of the clinical state in which circulating haemoglobin is present with iron in the oxidized (Fe3+) instead of the usual Fe2+ state.

Methaemoglobinaemia

Where does Methaemoglobinaemia arise from

hereditary deficiency of methaemoglobin reductase deficiency or inheritance of a structurally abnormal haemoglobin (Hb M)

What illness is likely to show in patients with Methaemoglobin

Cyanosis

What process does Haemoglobin use to generate ATP

anaerobic glycolytic (Embden–Meyerhof) pathway

What is glucose metabolised to through facilitated transfer in RBC

Lactate

What is generated in the breakdown of Glucose

NADPH, NADP

For every Glucose molecule used, How many ATP molecules are generated

The energy generated is used for the maintenance of what in RBC

Shape, flexibility, volume

What is the enzyme methaemoglobin reductase used for

Reduce functionally dead methaemoglobin containing ferric iron, to functionally active, reduced haemoglobin containing ferrous ions

In Embden–Meyerhof pathway, Luebering–Rapoport shunt, or side arm, of this pathway generates what metabolite

2,3‐DPG

What pathway facilitates appx 10% of the glycolysis

Hexose monophosphate (pentose phosphate) shunt

What is linked with NADPH in Hexose monophosphate (pentose phosphate) shunt, to maintain sulphydril SH groups

Glutathione

What is the oxidative pathway for Hexose monophosphate (pentose phosphate) shunt

glucose‐6‐phosphate is converted to 6‐ phosphogluconate and so to ribulose‐5‐phosphate

The deficiency of what substance causes red cells to be extremely susceptible to oxidant stress

glucose‐6‐phosphate dehydrogenase

What process is used to number red cell proteins based on their mobility

Polyacrylamide gel electro- phoresis (PAGE)

What structural proteins make up the membrane skeleton in RBC

α and β spectrin, ankyrin, protein 4.1 and actin

What is described as a reduction in the haemoglobin concen- tration of the blood below normal for age and sex

Anaemia

What is the normal value of haemoglobin in adult males

less than 135g/L in adult males

What is the normal value of haemoglobin in adult females

115 g/L in adult females

From the age of 2 years to puberty, less than how much Hb indicates anaemia is present

less than 110g/L

What are the main causes of Anaemia

iron deficiency (hookworm, schistosomiasis), sickle cell diseases, thalassaemia, malaria and the anaemia of chronic disorders

True or False, Rapidly progressive anaemia causes less symptoms than anaemia of slow onset

False, causes more symptoms

Thee presence or absence of clinical features can be considered under what four major headings.

Speed of Onset, Severity, Age, Haemoglobin O2 dissociation curve

What are the different signs of Anaemia for a) iron deficiency b) haemolytic or megaloblastic anaemia c) sickle cell d) thalassaemia major

a) Koilonychia (spoon nails) with iron deficiency, b) jaundice with haemolytic or megaloblastic anaemias, c) leg ulcers with sickle cell and other haemolytic anaemias, d) bone deformi- ties with thalassaemia major.

What are the three different classifications of anaemia

microcytic, normocytic and macrocytic

True or False, The Mean Corpuscular Volume (MCV) is usually high in newborns but low in infancy

True

True or False, in normal pregnancy there is a decrease in MCV levels

False, there is an increase

Thalassaemia Anaemia of chronic disease (some cases) Lead poisoning Sideroblastic anaemia (some cases) is associated with which classification of Anaemia

Microcytic

After acute blood loss Renal disease Mixed deficiencies Bone marrow failure (e.g. post‐ chemotherapy, infiltration by carcinoma, etc.) is associated with which classification of anaemia

Normocytic, normochromic

Megaloblastic: vitamin B12 or folate deficiency Non‐megaloblastic: alcohol, liver disease, myelodysplasia, aplastic anaemia, etc. is associated with which type of anaemia

Macrocytic

MCH <27pg

Microcytic, hypochromic

MCV 80-95fL

Normocytic, normochromic

MCV >95fL

Macrocytic

MCH ≥27pg

Normocytic, normochromic

MCV <80fL

Microcytic, hypochromic

The laboratory finding of what two substances aid in distinguishing ‘pure’ anaemia from ‘pancytopenia’ (subnormal levels of red cells, neutrophils and platelets)

Leucocyte and platelet counts

What is the normal Reticulocyte count and percentage

0.5–2.5%, 50–150 × 109/L

True or False, The higher the Reticulocyte count, indicates the more severe of anaemia

True

How long does it take for an erythropoietin response after an acute major haemorrhage

6 hours

How long does it take before the reticulocyte count raises | How long does it take before the the reticulocyte reaches its maximum

2-3 days | 6–10 days

If the reticulocyte count is not raised in an anaemic patient, what does it suggest.

impaired marrow function or lack of erythropoietin stimulus

What red cell abnormality is formed from Oxidant damage– e.g. G6PD deficiency, unstable haemoglobin

Basket cell

What is examination is done when the cause of anaemia or other abnormality of the blood cells cannot be diagnosed from the blood count, lm and other blood tests alone

Bone marrow examination

What are the two methods for bone marrow examination done

aspiration or trephine biopsy

In aspiration of bone marrow, what is used to stain the liquid sample

Romanowsky technique

What is usually observed in the liquid aspiration samples

the proportion of the different cell lines assessed

True or false, trephine biopsy specimen is less valuable than aspiration when individual cell detail is to be examined

True

Which bone marrow examination, provides more of a panoramic view of the marrow

trephine biopsy

Which bone marrow examination, shows presence of fibrosis or abnormal infiltrates, with immunohistology

trephine biopsy

Why is Erythropoiesis term ineffective

Because 10%-15% of developing erythoblasts die within the marrow before reaching mature cells

What two substances facilitate the breakdown of Haemoglobin

Unconjugated Bilirubin. lactate dehydrogenase (LDH)

What is the site of Bone Marrow investigation

Posterior iliac rest

What stain is used in Trephine Biopsy

Haematoxylin and eosin; reticulin (silver stain)

How long does it take for the Results to be available in a) Aspiration b) Trephine Biopsy

a) 1-2 hours | b) 1-7 days

What does NADH prevent in haemoglobin

oxidation of haemoglobin

What does NADPH prevent in haemoglobin

keeps cell proteins in the membrane and haemoglobin in the reduced state