1>If plasma retinol is low measure RBP and if this is low check and give
Zinc and check Zinc again .Does anyone know the science behind this
The theory behind this one is similar to that for Vitamin E (below). As
retinol is transported in plasma bound to RBP it is thought that Retinol
deficiency could be due to Vit A malabsorption, decreased RBP
(malnutrition/acute phase) or both and thus labs should measure both and
report a molar ratio. The problem with this is mainly cost as (in Australia
at least) there is no government rebate for RBP (although there is one for
Prealbumin).
> 2>Vitamin e to fasting lipids ratio?
Vit E is transported in plasma bound to lipoproteins and thus a molar ratio
gives more information about the relative concentration of Vitamin E within
the lipoprotein particle. The added usefulness of this molar ratio for
Vitamin E c/f Vit A is that Vitamin E has a role within the lipoprotein
particle in preventing peroxidation of the lipid particle and thus the molar
ratio also gives one some idea of the 'functional' capacity of Vitamin E to
prevent lipid peroxidation. ie it is possible (eg in obstructive liver
disease) to have a 'normal' vitamin E when expressed as a concentration
within plasma but be 'deficient' when expressed as a concentration within
'lipid'. We express our 'lipid' concentration as Chol + Trig mainly because
of the difficulties in measuring total phospholipid.
> 3>Vitamin K .Protein induced vitamin k PIVKA11
PIVKA II (or acarboxyprothrombin) is a more specific functional assay of
Vitamin K sufficiency (ie it is increased in Vitamin K deficiency as Vitamin
K is required for normal gamma carboxylation of glutamic acid in
prothrombin) than prothrombin (or Vitamin K itself). In my experience it
does not add that much more to the assessment of Vitamin K deficiency than
the much simpler prothrombin time and is much more difficult to measure
(ELISA or HPLC).
Of course in terms of CF monitoring, the reason for measuring all of the
above is to detect and treat the fat malabsorption which is a hallmark of
the pancreatic insufficiency associated with the disease. There is some
evidence to suggest that detecting the fat malabsorption early (via the
above assays) and treating early (through enzymes and vitamin mixtures) has
a long term beneficial effect on CF patients.
Hope this has been useful.
Peter Vervaart BAppSci FAACB
Senior Scientist, Department of Clinical Biochemistry
Honorary Research Fellow, MCRI
Women's and Children's Health
Flemington Road
Parkville Victoria 3052
Australia
Phone: 613 9345 5906
Fax: 613 9349 1819
Mobile: 0409 233 738
Web: www.rch.unimelb.edu.au/biochem/gastro
----- Original Message -----
From: "Peter Stromberg" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, July 13, 2001 7:06 PM
Subject: CF STANDARD SETTING CONFERENCE--LONDON
> One of our paediatricians come back from the above with lots of questions.
> > I am quite interested to know the detail of the new cystic fibrosis
monitoring standards.
>
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