PBL
Micronutrients
Biochem
GI
100
The name of our PBL patient.
What is Gladys Benedict?
100
This deficiency is associated with koilonychia.
What is iron deficiency?
100
These tissues uptake glucose using GLUT1.
What is brain and red blood cells?
‣ GLUT 1 is insulin independent
‣ Brain will preferentially oxidize glucose (except starvation states -> ketones)
‣ RBC lack mitochondria -> oxidizes glucose under both fed & fasted states
100
Primary digestive organ in the body where most absorption occurs.
What is the small intestines?
200
RYGB causes decreased absorption surface of this organ.
What is the small intestines?
200
This condition is associated with low hemoglobin but normocytic MCV lab results.
What is *competing nutritional deficiencies (iron and vitamin B9/B12)?
*makes mean in the size of the RBC's (MCV) move in opposite directions: <<-Iron--MCV--B9/B12->>
NOTE: Higher RDW, indicating greater variation in size, is also consistent with a mixed anemia due to iron and folate deficiencies.
200
This hormone is key to maintaining blood glucose during fasting.
What is *glucagon?
‣ Glucagon: Mobilizes fuel (liver) and maintains blood glucose during fasting. *skeletal muscle is not impacted by glucagon
‣ Epinephrine: Mobilizes fuel during acute stress (e.g., running from a bear)
‣ Cortisol: Provides for changing requirements over the long term
200
The duodenum is mostly in this quadrant.
Wha is the right upper quadrant?
300
For lab tests on iron studies, this is the most useful indicator of iron deficiency.
What is ferritin?
"Serum ferritin – is an indication of the amount of stored iron in your body. Ferritin is the major storage protein for iron inside of cells. It is the most useful indicator of iron deficiency, as the ferritin stores can be significantly decreased before any fall in the serum iron concentration occurs."
300
This deficiency is associated with bone pain and muscle weakness.
What is *calciferol (vitamin D)?
*Fat-soluble vitamin that promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal bone mineralization and to prevent hypocalcemic tetany (involuntary contraction of muscles, leading to cramps and spasms). Activated via two stage hydroxylation (in liver, then kidney). Fat malabsorption: ↓ mixing with bile.
- Diagnostics: ↓ serum 25-hydroxyvitamin D, ↑ parathyroid hormone (PTH), ↓ calcium/phosphate
https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
300
This hormone mediates protein catabolism in the skeletal muscle.
What is cortisol?
- Provides amino acids needed as a substrate for gluconeogenesis in the liver
300
These cells are found in the follicle-associated epithelium of Peyer's patches and isolated lymphoid follicles.
What are M-cells (microfold cells)?
- Responsible for the uptake and transfer of antigens from the lumen into the subepithelium.
400
This condition could arise if our patient takes medications with liquid formulations that have mannitol or sorbitol.
What is dumping syndrome?
‣ Mannitol and sorbitol are nonabsorable sugars.
Ref:
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9291886/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7292522/
400
These four vitamins are cofactors for pyruvate dehydrogenase.
What are thiamine, riboflavin, niacin, and panthenic acid (Vitamins B1, B2, B3, and B5)?
*Pyruvate dehydrogenase complex requires 5 co-factors (Tender Loving Care For Nancy):
- Thiamine (B1)
- Lipoic acid
- Coenzyme A (B5)
- FAD (riboflavin, B2)
- NAD+ (B3)
400
This is the phosphorylation status of activated pyruvate dehydrogenase complex (PDC).
What is *de-phosphorylated?
*In the fasted state, all enzymes are phosphorylated with fasted state enzymes being activated and all fed state enzymes (e.g., PDC) being inactived.
‣ Pyruvate dehydrogenase complex (PDC): transition point between cytosolic and mitochondrial metabolism in the TCA (tricarboxylic acid) cycle, a process to oxidize pyruvate to generate NADH and FADH2.
‣ Allosteric effectors:
(+) Pyruvate, NAD+
(-) NADH, ATP (& acetyl-CoA)
400
Mucosal immune responses occur at inductive sites in this tissue as part of the gut-associated lymphoid tissue (GALT) system
What is the mucosa-containing lymphoid tissue (MALT)?
‣ The intestine. contains the most abundant immune cells of any tissue in the body. Collectively, MALT forms the largest immune organ in the body.
‣ Inductive sites are comprised of
◦ Peyer’s patches (PP): clusters of immune cells consisting of a predominant B-cell follicle, an interfollicular T-cell region, and various macrophages and DCs; substantial site for IgA1 B-cell development; located beneath a single layer of columnar cells known as the follicle-associated epithelium (FAE)
◦ mesenteric lymph nodes (MLN)
◦ isolated lymphoid follicles (ILF)
https://www.mdpi.com/2036-7422/15/3/48
500
This urinalysis lab result is associated with volume-depleted symptoms (diarrhea, poor appetite, and orthostatic BP).
What is *specific gravity?
* "Urine-specific gravity suggests patient's kidneys are concentrating the urine to the upper end of normal... She is concentrating her urine via increased ADH and an activated RAAS in an attempt to correct her hypovolemia."
500
This vitamin is a necessary cofactor for MetH form methionine synthase, an enzyme involved in the methylation of homocysteine to methionine.
What is *cobalamin (B12)?
‣ Both folate and B12 are important for thymidine synthesis (via thymidylate synthase, important for DNA synthesis) and metabolism of homocysteine.
‣ Deficiency in either folate or B12 causes decreased DNA synthesis (megaloblastic anemia) and increased homocysteine.
‣ B12 is unique from folate via odd chain fatty acid metabolism, which causes increased methylmalonic acid (MMA).
500
This regulatory enzyme is key to the process in the liver that utilizes acetyl-CoA to produce β-hydroxybutyrate and acetoacetate.
What is HMG CoA synthase (hydroxymethylglutaryl CoA synthase)?
‣ ketogenesis (fasted state): ketone bodies can be oxidized by peripheral tissues; the liver cannot oxidize ketones.
‣ the acetyl-CoA is produced through β-oxidation.
500
These ganglia contain neurons whose postganglionic axons innervate the distal esophagus, stomach, proximal duodenum, liver, gallbladder, spleen, kidney, and the small intestine.
What is the *celiac ganglion?
*T5-T9 -> preganglionic greater splanchnic n. -> celiac ganglia -> postganglionic fibers of the embryonic derivatives of the foregut.