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A comparison of metabolic pathway dynamics in man and other mammals

Thesis (Maters Diploma (Medical Technology)--Cape Technikon, Cape Town, 1993 / The object of the present study was to determine
whether there was a difference in the flux through two
different metabolic pathways, the purine salvage pathway
and the urea cycle, in skin fibroblasts from three species.
A double label approach was adopted to measure the
incorporation of the purine bases, hypoxanthine and adenine,
and the amino acids, citrulline and arginine in acid
precipitable material.
Before examining the between species variation it was
necessary to examine different levels of possible variation
such as the variation between individuals from each species,
the variation between separate experiments and the
replication error within experiments.
Eight individuals from each of three species, bUffalo,
human, and rhinoceros were examined with the labelled purine
bases. Skin fibroblasts from four humans and eight
rhinoceros individuals were also examined over varying
passage numbers until the fibroblasts senesced, to determine
the effect of ageing on the uptake of hypoxanthine and
adenine.
The same four human fibroblast cultures were
transformed with a transforming virus and examined to see
the effects of transformation on the uptake of the purine
bases, these transformed fibroblasts were compared with
previously transformed rhinoceros fibroblasts. The uptake of
labelled citrulline and arginine was also examined in three
individuals from each of the three species.
The major part of variation throughout the study was
found to be at the between experiment level, despite
stringently controlled conditions. This between experiment
variation obscured any variation found within individuals
from each species.
In spite of this major between - experiment variation,
the results showed that there was significant variation
between the three species in the uptake of hypoxanthine.
Adenine uptake was similar in the buffalo and human, but was
significantly different between both these species and the
rhinoceros.
citrulline uptake showed no variation between the three
species, whereas arginine showed a significant variation
between the rhinoceros and the other two species. Buffalo
and human showed no significant variation in arginine
uptake.
There was a significant increase in the uptake of
hypoxanthine and adenine in transformed fibroblasts relative
to untransformed fibroblasts.
As a consequence of the significant between-experiment
variation demonstrated in this study, it is apparent that
great care must be taken to standardize the conditions when
using a double label approach, especially if the assay is to
be used for the diagnosis of inborn errors of metabolism.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:cput/oai:localhost:20.500.11838/1486
Date January 1993
CreatorsBaumgarten, Ingrid M
PublisherCape Technikon
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Rightshttp://creativecommons.org/licenses/by-nc-sa/3.0/za/

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