|dc.description.abstract||• 1. The thesis describes an investigation into the presence
and quantities of four free, monosaccharides, L- arabinose, D-xylose,
D-ribose and (presumably -) fucose in the urine of healthy human
subjects and of patients suffering from renal failure.
• 2. Two new quantitative analytical procedures based on one -
dimensional thin-layer chromatography have been devised whereby it
has become possible for the first time rapidly (3 h) to separate and
measure at microgram levels, arabinose, ribose, xylose and fucose
from the numerous other sugars present in urine from human subjects.
On thin -layers of Kieselguhr G buffered with sodium acetate (acetate
plate), arabinose and ribose are measured. On thin-layers of
Kieselguhr G buffered with sodium dihydrogen phosphate (phosphate
plate), fucose is determined. Xylose is measured by difference
between ribose on an acetate plate and xylose plus ribose on a
phosphate plate. Previously, only one complicated technique,
occupying 5 days for the paper chromatography was available (Date,
1958a, 1958b, 1958c and 1966).
• 3. The spraying reagents used to colour the sugar spots can
detect qualitatively to the lowest limit of 0.5 μg of each sugar on
the devised t.l.c. systems. The new PABA reagent visually
distinguishes different sugar classes on the both t.l.c. systems.
This reagent may be employed for quantitative measurements whereby
linear relationship holds upto 30 μg for recovered colour of xylose
from acetate plates and upto 80 μg for fucose from phosphate plates.
Using the p-anisidine hydrochloride staining reagent, quantitative
spectrophotometric determination of the extracted sugar spots is
possible to the lowest limit of 2.5 μg for each sugar; linear
relationship holds upto 8.0 dug for each sugar on either plate.
• 4. Preparatory to chromatography, deionisation of urine samples
is obligatory and accomplished by means of ion- exchange resins
Amberlite IR-120 (H⁺) and Amberlite IRA -400 (acetate) using two glass
columns in tandem.
• 5. Specificity is conferred on the estimates by the comparable
behaviours of the urinary aldopentoses and fucose so estimated and
the authentic sugars on the thin-layer chromatograms.
• 6. The separation of the sugars on the devised thin-layers is
always reproducible. Quantitative reproducibilities (coefficient of
variations) in a septuplicate analysis of the same urine sample show
arabinose as 13.1%, xylose 15%, ribose 7.2% and fucose 10.2%. The
mean±S.D. recoveries of 10-30 μg of arabinose, xylose, ribose and
fucose added to the same urine samples in six experiments are 93%±5%
(range 80-113%), 101%±41% (range 50-166 %), 95%±9% (range 85-110%) and
95%±14% (range 80-110%) respectively.
• 7. All urine samples of six fasting healthy males and six
fasting healthy females invariably contain arabinose, xylose, ribose
and fucose. These sugars must presumably originate in endogenous
processes. There is no significant difference in the excretion
between the corresponding sugars in fasting state in two sexes. The
mean fasting rates of excretion (,ig/min) of the sugars for the twelve
subjects are 13.3±3.4 (arabinose), 8.5±1.9 (xylose), 5±1.5 (ribose)
and 16.6±5.6 (fucose).
• 8. Consuming an ample diet, free as far as possible from known
sources of aldopentoses, healthy subjects at three different periods
of the day excrete the sugars at rates unchanged from those in the
fasting state. It is suggested that these sugars are excreted at
constant rate independently of the urine volume.
• 9. On diets potentially rich in aldopentoses, the subjects of
(8) show increased rates of excretion of aldopentoses, mainly that of
xylose and less so of arabinose. Noteworthy is the fact that rates
of excretion of both ribose and fucose were not increased.
• 10. Urines from all six patients with various forms of renal
failure repeatedly show the same picture. Ribose is always excreted
at the lower end of the normal range while arabinose, xylose and
fucose, if detectable, are excreted only in unmeasurable amounts.
• 11. The results are compared and discussed with other workers'
findings. In so far as any reasonable suggestions can be made, the
excretion of these four monosaccharides in health and in renal
failure are discussed in the light of our knowledge of the somatic
origins and metabolism of arabinose, ribose, xylose and fucose. The
prospects of employing this technique and the measurements of these
sugars in certain diseases are indicated.||en