dowjunk
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bioguy wrote:Presentation of Apolipoprotein B deficiency - ? Ok, I don't have patience to wait for the answer. I will answer it myself with some thoughts and please let me know if I am wrong, or you can add some more to it. Presentation - Hemolytic anemia, Ataxia, Acanthocytes, Vit E def (HAVE some more fat, dear)  Deficiency of B48 and B100 interrupts the formation of Chylomicrons, VLDL and LDL - so Malabsorption (of fat I suppose) leading to Deficiency of Vitamin (why only E, why not all Fat soluble vitamins) - Vit E def. causes Hemolytic anemia, Ataxia and Acanthocytes. Excerpt from Harrison's Most clinical manifestations of abetalipoproteinemia result from defects in the absorption and transport of fat-soluble vitamins. Vitamin E and retinyl esters are normally transported from enterocytes to the liver by chylomicrons, and vitamin E is dependent on VLDL for transport out of the liver and into the circulation. As a consequence of the inability of these patients to secrete apoB-containing particles, patients with abetalipoproteinemia are markedly deficient in vitamin E and are also mildly to moderately deficient in vitamin A and vitamin K.
Bioguy u r really patientt  man, I worry what you will do while waiting for stp1 results, lol
ApoB deficiency will have it's patients in two pathological messes: one, he'll have accumulation of lipids in the villi as there are no chylomicron-transport-partners (the apo B48) to take it to the liver. So chylomicrons accumulate in the villi! Two, since we donot have a supply of tryacylglycerols in the body as it is not getting transported from the villi; there is no VLDL in the body. No VLDL=no transport of cholesterol from the liver! Going into further detail: since LDL is also lacking, the post hydrolysis of VLDL (by capillary lipoprtn lipase) wil also get affected for two reason,(a) no LDL (b) no apoB100.
As you said bioguy: deficiency of chylomic, LDL and VLDL occurs due to deficency of apoB48 & apoB100 !!!
now to my Q, how'd u differ this with type 3 dysbetalipoproeinemia (apo lipoprotein E deficiency)...I need the mechanism people, the mechanism.....
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| dowjunk
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Q8 In Sturge Weber syndrome, the patient has a birthmark/Salmon patch on the ophthalmic Nv dermatome.............Is there an assocaited brain patholgy in this synd? What is it?
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| dowjunk
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Q9 What is the presentation in a patient e POSTPHLEBITC SYNDROME?
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| dowjunk
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Q10 Match the alphabets e numericals:
A-HCV B-cANCA C-cervical adenopathy D-elastic artery E-high ESR
1-Giant cell arteritis 2-Berger's disease 3-Kawasaki 4-Wegener's granulomatosis 5-cryoglubinemia
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| dowjunk
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Newnlost i thot lipoxygenase and thrombaxane A2 mite be the the culprits in PPH............but may be they are not that significant> Endothelin yes is an important player, but I'll have to xplain myself why LO and TA2 arent....
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| dowjunk
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Please do not forget......we'll be going for CARDIAC PATHOLOGY NEXT WEEKEND. It will be our Drill 2!
Lets keep posting Vascular Patho till then!
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| dowjunk
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Important CLUE:
If a patient with OCD or Graves disease presents to us, we have to take HTN in perspective!
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| bioguy
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Q10 Match the alphabets e numericals:
A-HCV 5-cryoglubinemia
B-cANCA 4-Wegener's granulomatosis
C-cervical adenopathy 3-Kawasaki
D-elastic artery
E-high ESR 1-Giant cell arteritis
2-Berger's disease
not sure if Berger's affects elastic arteries. i thought it was muscular arteries - esp. digital vessels.
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| bioguy
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dowjunk wrote:Newnlost i thot lipoxygenase and thrombaxane A2 mite be the the culprits in PPH............but may be they are not that significant> Endothelin yes is an important player, but I'll have to xplain myself why LO and TA2 arent....
Mechanistically, TA2 is a vasoconstrictor and thats true. But actually there is "probably" no role played by TA2 in Idiopathic Pulmonary HTN per se.
Excerpt from CMDT08
As opposed to the systemic circulation, the pulmonary resistance is influenced by local vascular mediators much more than the adrenergic nervous system, even though both alpha- and beta-receptors are present on pulmonary vascular smooth muscle.
The normal pulmonary endothelial cell maintains the vascular smooth muscle in a state of relaxation.
Pulmonary vasoconstriction is mediated by hypoxia and by endothelin and angiotensin II.
Vasodilation can be affected by certain prostaglandins, endothelin receptor blockers, smooth muscle relaxants, and by nitric oxide.
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| bioguy
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dowjunk wrote:
Q8 In Sturge Weber syndrome, the patient has a birthmark/Salmon patch on the ophthalmic Nv dermatome.............Is there an assocaited brain patholgy in this synd? What is it?
the answer to this question is SWOOP
opthalmic artery (naevus)
occipital lobe
parietal lobe
(malformation of meningeal vessels in piamater of -)
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| bioguy
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dowjunk wrote:
Q9 What is the presentation in a patient e POSTPHLEBITC SYNDROME?
Edema (increased hydrostatic pressure)
Ulceration (mechanism anyone???)
Pigmentation (hemosiderin from exudates),
and Fibrosis (probably a failed healing mechanism)
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| bioguy
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dowjunk wrote:
Important CLUE:
If a patient with OCD or Graves disease presents to us, we have to take HTN in perspective!
Why in OCD??
man!!! i have OCD but my BP is normal. (thankfully)
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| bioguy
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This is so low yield yet confusing and time-consuming to master 
B-48 - Chylomicrons
B-100 - VLDL
E - binds LDL receptor
CII - LPL cofactor
HDL is the supplier of E and Cs
Chylomicrons made in small intestine
VLDL made in Liver
LPL (adipose, heart, muscle) - metabolizes chylomicrons and VLDL
to Chylomicron remnants and IDL respectively
E on chylomicron remnants and IDL bind to LDL receptor (in liver) and assists in their metabolism
IDL is converted to LDL and released into circulation
LDL is again endocytosed by LDL receptor (liver) and thats the end of story.
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| bioguy
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So in Apolipoprotein B deficiency (Abetalipoproteinemia) there is no B48 and B100 - so no Chylomicrons from intestine, and no VLDL from liver (so no IDL and LDL)
In Type III Hyperlipoproteinemia (Familial Dysbetalipoproteinemia/Remnant disease) there is no E - so no binding of Chylomicron remnants and VLDL to LDL receptor - so no metabolism of these lipoproteins. They accumulate.
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| bioguy
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dowjunk wrote:bioguy wrote:
If an embolus passes down the aorta from left heart - what are the chances that it will go into the celiac trunk, inferior mesenteric, renal arteries or all the way down into iliacs.
no need of exact statistics, just rational discussion. this is continuation of my question - differences in thrombus v/s embolism of gut circulation. i don't even know if this is pertinent to USMLE. i am just curious.
a thrombus in inf/sup mesenteric artery is due to atherosclerosis i suppose. so if a thrombus of equal stenosing level occurs in two arteries one supplying to splenic flexure and other to say duodenum then -
infarction occurs in splenic flexure due to watershed concept,
will infarction not occur in duodenum ? if so/not why?
Lets make sure that the thromboemboli phenomenon in GI tract will not give time for angiogenesis, and if it is caused by a preexisting atheroma, the infarctions are rare and if do happen, they are very small! The superior mesenteric artery is prone to be affected by a thrombus due to the angle at the origin and hence its the small bowel, who's unlucky. Duodenum gets thru due to dual supply by the ending anastomosis of celiac.
Excellent answer. Let me add more...
Because of the rich collateral network in the mesentery, generally at least two of the three major visceral vessels (celiac, superior mesenteric, inferior mesenteric arteries) are affected before symptoms develop. (exception: splenic flexure, as discussed before).
Visceral artery insufficiency - acute and chronic
acute - thrombus, embolus, low flow states (CHF, shock)
chronic - normal flow at resting states, but insufficiency occurs with severe abdominal pain when flow demands increase with feeding.
ref: CMDT08
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| Tiff
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bioguy wrote:This is so low yield yet confusing and time-consuming to master B-48 - Chylomicrons B-100 - VLDL E - binds LDL receptor CII - LPL cofactor HDL is the supplier of E and Cs Chylomicrons made in small intestine VLDL made in Liver LPL (adipose, heart, muscle) - metabolizes chylomicrons and VLDL to Chylomicron remnants and IDL respectively E on chylomicron remnants and IDL bind to LDL receptor (in liver) and assists in their metabolism IDL is converted to LDL and released into circulation LDL is again endocytosed by LDL receptor (liver) and thats the end of story.
Have to disagree here. According to Goljan RR Biochem...
B-48 - chylomicron transport
B-100 - LDL transport; binds to LDL receptors
E - uptake of chylomicron remnants and IDL by liver
CII - activates capillary lipoprotein lipase to release fatty acid and glycerol from chylomicrons, VLDL, & IDL
HDL - has A-1, C-II, E. But Chylomicrons and VLDL have C-II and E as well. HDL remains a resevoir.
Edited by Tiff on 03/30/08 - 04:44 PM
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| Tiff
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bioguy wrote:Presentation of Apolipoprotein B deficiency - ? Ok, I don't have patience to wait for the answer. I will answer it myself with some thoughts and please let me know if I am wrong, or you can add some more to it. Presentation - Hemolytic anemia, Ataxia, Acanthocytes, Vit E def (HAVE some more fat, dear) Deficiency of B48 and B100 interrupts the formation of Chylomicrons, VLDL and LDL - so Malabsorption (of fat I suppose) leading to Deficiency of Vitamin (why only E, why not all Fat soluble vitamins) - Vit E def. causes Hemolytic anemia, Ataxia and Acanthocytes. Excerpt from Harrison's Most clinical manifestations of abetalipoproteinemia result from defects in the absorption and transport of fat-soluble vitamins. Vitamin E and retinyl esters are normally transported from enterocytes to the liver by chylomicrons, and vitamin E is dependent on VLDL for transport out of the liver and into the circulation. As a consequence of the inability of these patients to secrete apoB-containing particles, patients with abetalipoproteinemia are markedly deficient in vitamin E and are also mildly to moderately deficient in vitamin A and vitamin K.
Great explanation. Wanted to add that another clinical manifestation is retinitis pigmentosa.
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| bioguy
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Tiff wrote:bioguy wrote:This is so low yield yet confusing and time-consuming to master B-48 - Chylomicrons B-100 - VLDL E - binds LDL receptor CII - LPL cofactor HDL is the supplier of E and Cs Chylomicrons made in small intestine VLDL made in Liver LPL (adipose, heart, muscle) - metabolizes chylomicrons and VLDL to Chylomicron remnants and IDL respectively E on chylomicron remnants and IDL bind to LDL receptor (in liver) and assists in their metabolism IDL is converted to LDL and released into circulation LDL is again endocytosed by LDL receptor (liver) and thats the end of story. Have to disagree here. According to Goljan RR Biochem... B-48 - chylomicron transport B-100 - LDL transport; binds to LDL receptors E - uptake of chylomicron remnants and IDL by liver CII - activates capillary lipoprotein lipase to release fatty acid and glycerol from chylomicrons, VLDL, & IDL HDL - has A-1, C-II, E. But Chylomicrons and VLDL have C-II and E as well. HDL remains a resevoir.
 i didn't understand where you were disagreeing
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| bioguy
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"The proteins associated with lipoproteins, called apolipoproteins, are required for the assembly, structure, and function of lipoproteins. Apolipoproteins activate enzymes important in lipoprotein metabolism and act as ligands for cell surface receptors."
B-48 is associated with chylomicron (involved in its assembly, structure and function - including transport)
B-100 is associated with VLDL and remains as VLDL is coverted to IDL and then to LDL.
E binds to LDL receptor - chylomicron remnants and IDL and LDL are all taken up by liver via binding to LDL receptor
CII acts as a cofactor for LPL (Lipoprotein Lipase) which is same as "activating capillary lipoprotein lipase"
and HDL is the supplier of Apoproteins - to Chylomicrons, VLDLs
Ref: Harrison's and Harper's
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| bioguy
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Chylomicron metabolism from Harper's - excellent review
Attached Files:
Chylomicrons.gif (33 KB, 2 downloads)
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| bioguy
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VLDL-IDL-LDL metabolism from Harper's
Attached Files:
VLDL.gif (37 KB, 3 downloads)
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| dowjunk
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Bioguy and Tiff.....u r making me feel like a #@^%. Great work.....lets keep it rolling!
OCT, if not OCD for you bioguy...man...its the oral contraceptive thing....sorry for being too synonymous!
Yes Bergers is muscular art...........D2 and E2....bergers is an answer remnant to fool my fellows..............dint work though!!! lol.......Elastic artery matches with tempral art gain.
Stasis of venous blood leads to ulcer on the medial aspect of the shin....i am not sure if there is any other biochemical involvement too!
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| dowjunk
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Thanks for the attachments bioguy....I needed it to...i am specializing in cholesterol n stuff at the moment.
GUYS I M HAVING FUN HERE!
Q11 A 38-year-old man has had increasing dyspnea with peripheral edema, worsening for the past two years. On physical examination he has diffuse crackles auscultated in both lungs. A chest radiograph shows that the heart nearly fills the chest. A chest CT scan demonstrates a 10 cm mass involving the right ventricle that appears to have areas of hemorrhage and necrosis within it. Which of the following neoplasms is this man most likely to have?
A Rhabdomyosarcoma
B Mesothelioma
C Myxoma
D Angiosarcoma
E Papillary fibroelastoma
F Kaposi sarcoma
G Rhabdomyoma
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| dowjunk
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Plz be elaborative:
Q12 A 17-year-old girl is brought to the physician because she remains short in stature for her age. She has not shown any changes of puberty. On physical examination her vital signs include T 37 C, RR 18/minute, P 75/minute, and BP 165/85 mm Hg. She has a continuous murmur heard over both the front of the chest as well as her back. Her lower extremities are cool with poor capillary filling. She has a webbed neck. A chest radiograph reveals a prominent left heart border, no edema or effusions, and rib notching. Which cardiovascular abnormalities is she most likely to have? Can u suggest another associated problem this girl might have?
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| dowjunk
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Q13 A 44-year-old woman dies as a consequence of a "stroke". At autopsy, she is found to have a large right basal ganglia hemorrhage. She has an enlarged 550 gm heart with predominantly left ventricular hypertrophy. Her kidneys are small, about 80 gm each, with cortical scarring, and microscopically they demonstrate small renal arterioles that have luminal narrowing from concentric intimal thickening. Which of the following is the most likely diagnosis?
A Dominant polycystic kidney disease
B Arterial changes with diabetes mellitus
C Vascular disease with hyperlipidemia
D Malignant hypertension
E Monckeberg's sclerosis
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