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The latent emulsifying capacity of human serum
CLINICA CHIMICA ACTA
THE
LATENT
B. BREYER,
557
EMULSIFYING
F. OFNER
AND
Unit of Clinical Investigation, (Received
June z&h,
CAPACITY
OF HUMAN
SERUM
G. ANDREW3
State Hospital, Lidcombe, N.S.W.
(Australia)
1964)
SUMMARY
By combining optical density determinations with measurements of the emulsifying capacity (E.C.), the emulsification reserves, or “Latent Emulsifying Capacity”, of serum was estimated. It is shown that there exists a correlation between the Initial Turbidity (I.T.) of a serum and Latent Emulsifying Capacity (Latent E.C.). Three types of fat absorption patterns are described. It appears that E.C. measurements
can be used as a test for the presence
of fat malabsorption.
INTRODUCTION
In two previous communications11 2, a method for estimating the Emulsifying Capacity (E.C.) of blood sera and the changes produced by the presence of heparin were reported. The object of the present study was to investigate E.C. changes following the ingestion of fats. Previous results seemed to suggest that by increasing the amount of ingested fat the E.C. will decrease and the present investigation is concerned with the measurement of these changes. The measurements were combined with turbidimetric determinations of postprandial sera in order to investigate any correlation between E.C. values and postprandial alimentary lipaemia. Since it is known that the incidence of milky, lipaemic sera is increased in alcoholics3, we secured the voluntary co-operation of a group of male alcoholics aged from 25 to 50 years. Thirty-three volunteers who were undergoing treatment for their addiction participated in this investigation; they were subjected to a set of tests in order to exclude any underlying pathology. Three patients were found to suffex from malabsorption. MATERIALS
AND METHOD
The blood was taken by venipuncture after fasting and after two standard breakfasts, the first including t and the second & a pint of cream. The turbidity measurements were carried out with an E.E.L. Portable Colorimeter model A and a red filter type ORI. All figures quoted represent extinction values. The procedure used was exactly the same as that described1 except that all Clin. Chim. Acta,
II
(1965) 557-560
B. BREYER et d.
558
experiments were carried out by adding to the serum not 0.5 but only 0.25% olive oil; the shaking time was increased to 45 min at room temperature. RESULTS
For every serum the following values were estimated: I. The “Initial Turbidity” (I.T.) that is the optical density of the serum measured immediately after its separation from the blood clot. 2. The “Total Emulsifying Capacity” (Total E.C.) that is the optical density after the addition and emulsification of 0.257& of olive oil to the serum. 3. The “Latent Emulsifying Capacity” (Latent E.C.) that is the difference between the I.T. and the Total E.C. value; hence Latent EC. = Total E.C.--1.T. Blood from fasting patients was withdrawn early in the morning, IO h after their light evening meal, For the determination of the postprandial lipaemia blood was taken 3 h after the standard breakfast, at the height of postabsorptive lipaemia4. The range of values found is shown in Table I. TABLE -.Seva
I
-.. ..-
___-_.
Fasting After $ pint cream After & pint creaxn
Total E. 6. range
0.01-0.16
0.24-0.43 0.21-0.77
0.04.-0.67
0.25-0.69 ..~
~~
I. ‘T. range
___-
-
0.32-0.92
-.
Latent
E. C. range
0.1G-0.40 0.11-0.24 0.06-0.26 -.-
More information was gained by comparing total E.C. and I.T. values. As shown in Table II, three types of absorptive patterns could be distinguished: after ingestion of fat in Type I, the I.T. increased markedly as did the corresponding total E.C. values. In Type II, there was little change in the I.T. but a significant decrease in the total E.C. values. In Type III, there was little change in both the LT. and the total E.C. values. TABLE _.__
II
__
--
-~____-
Seva
I.T.
Total E.G. __~__....
Fasting After t pint
0.06 0.56
0.28
Fasting After $ pint
0.08 0.04
0.3’ 0.21
Fasting After a pint
0.05 0.09
0.28
0.69
0.28
i
I
Type 1 Type II
I Type III (
DISCUSSION
It is a well established fact that the amounts of particulate fat in serum can be assessed by turbidimetric methods. Optical density determination is an accepted way of measuring the rate of lipid absorption and has been suggested as an adequate screening test for lipid absorption disturbances 4.
LATENT
EMULSIFYING
We thought urements
CAPACITY
OF SERUM
that by combining
an indication
559
optical density
could be gained of the ability
determination
with E.C. meas-
of sera to keep fat particles
in
a state of dispersion and an assessment made on the correlation between optical density and the existing E.C. reserves. We propose to call these emulsifying reserves the Latent E.C. because they are a measure of the emulsification power which a serum possesses over and above that required for the emulsification of the absorbed alimentary fats. Hence we expected to find that an increased dietary fat load will be followed by a commensurate reduction in the Latent E.C. In general, the present experiments confirmed our expectations. Table I shows that the values in the range of Latent E.C. diminished as the quantity of dietary fat increased. However, the Latent E.C. of a fasting person could not always be taken as a yardstick to predict its magnitude in the postprandial, lipaemic state. Thus in one person the fasting Latent E.C. was as high as 0.32 and fell to 0.15 after -i a pint of cream. In another case the fasting Latent E.C. of only 0.18 diminished only very little,
to 0.16, after the same lipid intake. A more consistent correlation was found between the I.T. and the Latent values. As a rule, higher turbidity values were associated with a lower Latent as evident
TABLE _______ .%a
from Table
E.C. E.C.
III.
111
Fasting After * pint cream After $ pint cream
I. T.
Latent
,4 verage values
Extveme
0.07 0.34 0.54
o.or-0.16 0.04-0.56 0.43-0.70
range
Average 0.23 0.17 0.12
E.C. ~___~_~~__ values Extreme
vange
0.16-0.26 o.*o-0.24 0.08-0.18
There was, however, no constant ratio between the I.T. and the Latent E.C. values. Thus in one case the fasting I.T. was 0.07 with a Latent E.C. of 0.17 which, after the ingestion of + a pint of cream, fell to 0.07 whilst at the same time the I.T. rose to 0.65, an almost tenfold increase of the original value. Ordinarily, after fat ingestion an increase in the I.T. values should be expected with a corresponding change in the total E.C. (Type I). In a certain number of cases, however, there is no appreciable change in the I.T. after fat ingestion and the presence of molecular (invisible) fats, in contradistinction to particulate fats, is immediately revealed by a diminished Total E.C. value (Type II). There seems to be little doubt that the drop in the E.C. is due to the fact that the active sites on the protein molecule have been occupied by the molecular fats, thus impairing the total E.C. of the serum. If this reasoning is correct, it should be expected that in cases of fat malabsorption both the I.T. and total E.C. values after a fatty meal should remain unchanged. This seems, in fact, to be the case (Type III). In three patients suffering from fat malabsorption, as confirmed by conventional tests, we found that the I.T. values before and after the test meal remained unchanged, obviously because of the impaired fat absorption; at the same time, the total E.C. values also remained unchanged as opposed to Type II. This behaviour is evidently due to reduced quantities of molecular fats in the serum. Hence, measurement of total E.C. before and after a fatty meal seems to constitute a test for the diagnosis of fat malabsorption. Cliti.
CJZ~WI.A4cta, II (1965)
j57p560
B. BREYER
560
et al.
ACKNOWLEDGEMENTS
We are grateful
to Dr. C. J. Cummins,
the Director
General
of Health,
New
South Wales, for permission to publish this paper. Our thanks are also due to Dr. G. C. Hughes, Medical Superintendent, Lidcombe State Hospital and Home, for supporting this investigation. We are grateful to Dr. H. Kramer, Director, Institute of Clinical Pathology and Medical Research, Lidcombe, for making available the facilities of the Institute. We also thank Mr. G. Tormay and his staff for their valuable technical assistance. REFERENCES
I B. BREYER AND 2 B. BREYER AND 3 E. MERIAN AND 4 L. STUTMAN, M. Clin. Chim.
Acta.
P. B. GOODWIN, Clin. Chim. Acta, 7 (1962) 647. F. OFNER, Clin.Chirn. Acta, 8 (1963) 173. L. FINCKER, Strasbourg Med., 13 (1962) 80. GEORGE AND L.GOTTSCH, Am.J.Med. Sk., 242 (1961) II (1965)
557-560
736.
THE
LATENT
B. BREYER,
557
EMULSIFYING
F. OFNER
AND
Unit of Clinical Investigation, (Received
June z&h,
CAPACITY
OF HUMAN
SERUM
G. ANDREW3
State Hospital, Lidcombe, N.S.W.
(Australia)
1964)
SUMMARY
By combining optical density determinations with measurements of the emulsifying capacity (E.C.), the emulsification reserves, or “Latent Emulsifying Capacity”, of serum was estimated. It is shown that there exists a correlation between the Initial Turbidity (I.T.) of a serum and Latent Emulsifying Capacity (Latent E.C.). Three types of fat absorption patterns are described. It appears that E.C. measurements
can be used as a test for the presence
of fat malabsorption.
INTRODUCTION
In two previous communications11 2, a method for estimating the Emulsifying Capacity (E.C.) of blood sera and the changes produced by the presence of heparin were reported. The object of the present study was to investigate E.C. changes following the ingestion of fats. Previous results seemed to suggest that by increasing the amount of ingested fat the E.C. will decrease and the present investigation is concerned with the measurement of these changes. The measurements were combined with turbidimetric determinations of postprandial sera in order to investigate any correlation between E.C. values and postprandial alimentary lipaemia. Since it is known that the incidence of milky, lipaemic sera is increased in alcoholics3, we secured the voluntary co-operation of a group of male alcoholics aged from 25 to 50 years. Thirty-three volunteers who were undergoing treatment for their addiction participated in this investigation; they were subjected to a set of tests in order to exclude any underlying pathology. Three patients were found to suffex from malabsorption. MATERIALS
AND METHOD
The blood was taken by venipuncture after fasting and after two standard breakfasts, the first including t and the second & a pint of cream. The turbidity measurements were carried out with an E.E.L. Portable Colorimeter model A and a red filter type ORI. All figures quoted represent extinction values. The procedure used was exactly the same as that described1 except that all Clin. Chim. Acta,
II
(1965) 557-560
B. BREYER et d.
558
experiments were carried out by adding to the serum not 0.5 but only 0.25% olive oil; the shaking time was increased to 45 min at room temperature. RESULTS
For every serum the following values were estimated: I. The “Initial Turbidity” (I.T.) that is the optical density of the serum measured immediately after its separation from the blood clot. 2. The “Total Emulsifying Capacity” (Total E.C.) that is the optical density after the addition and emulsification of 0.257& of olive oil to the serum. 3. The “Latent Emulsifying Capacity” (Latent E.C.) that is the difference between the I.T. and the Total E.C. value; hence Latent EC. = Total E.C.--1.T. Blood from fasting patients was withdrawn early in the morning, IO h after their light evening meal, For the determination of the postprandial lipaemia blood was taken 3 h after the standard breakfast, at the height of postabsorptive lipaemia4. The range of values found is shown in Table I. TABLE -.Seva
I
-.. ..-
___-_.
Fasting After $ pint cream After & pint creaxn
Total E. 6. range
0.01-0.16
0.24-0.43 0.21-0.77
0.04.-0.67
0.25-0.69 ..~
~~
I. ‘T. range
___-
-
0.32-0.92
-.
Latent
E. C. range
0.1G-0.40 0.11-0.24 0.06-0.26 -.-
More information was gained by comparing total E.C. and I.T. values. As shown in Table II, three types of absorptive patterns could be distinguished: after ingestion of fat in Type I, the I.T. increased markedly as did the corresponding total E.C. values. In Type II, there was little change in the I.T. but a significant decrease in the total E.C. values. In Type III, there was little change in both the LT. and the total E.C. values. TABLE _.__
II
__
--
-~____-
Seva
I.T.
Total E.G. __~__....
Fasting After t pint
0.06 0.56
0.28
Fasting After $ pint
0.08 0.04
0.3’ 0.21
Fasting After a pint
0.05 0.09
0.28
0.69
0.28
i
I
Type 1 Type II
I Type III (
DISCUSSION
It is a well established fact that the amounts of particulate fat in serum can be assessed by turbidimetric methods. Optical density determination is an accepted way of measuring the rate of lipid absorption and has been suggested as an adequate screening test for lipid absorption disturbances 4.
LATENT
EMULSIFYING
We thought urements
CAPACITY
OF SERUM
that by combining
an indication
559
optical density
could be gained of the ability
determination
with E.C. meas-
of sera to keep fat particles
in
a state of dispersion and an assessment made on the correlation between optical density and the existing E.C. reserves. We propose to call these emulsifying reserves the Latent E.C. because they are a measure of the emulsification power which a serum possesses over and above that required for the emulsification of the absorbed alimentary fats. Hence we expected to find that an increased dietary fat load will be followed by a commensurate reduction in the Latent E.C. In general, the present experiments confirmed our expectations. Table I shows that the values in the range of Latent E.C. diminished as the quantity of dietary fat increased. However, the Latent E.C. of a fasting person could not always be taken as a yardstick to predict its magnitude in the postprandial, lipaemic state. Thus in one person the fasting Latent E.C. was as high as 0.32 and fell to 0.15 after -i a pint of cream. In another case the fasting Latent E.C. of only 0.18 diminished only very little,
to 0.16, after the same lipid intake. A more consistent correlation was found between the I.T. and the Latent values. As a rule, higher turbidity values were associated with a lower Latent as evident
TABLE _______ .%a
from Table
E.C. E.C.
III.
111
Fasting After * pint cream After $ pint cream
I. T.
Latent
,4 verage values
Extveme
0.07 0.34 0.54
o.or-0.16 0.04-0.56 0.43-0.70
range
Average 0.23 0.17 0.12
E.C. ~___~_~~__ values Extreme
vange
0.16-0.26 o.*o-0.24 0.08-0.18
There was, however, no constant ratio between the I.T. and the Latent E.C. values. Thus in one case the fasting I.T. was 0.07 with a Latent E.C. of 0.17 which, after the ingestion of + a pint of cream, fell to 0.07 whilst at the same time the I.T. rose to 0.65, an almost tenfold increase of the original value. Ordinarily, after fat ingestion an increase in the I.T. values should be expected with a corresponding change in the total E.C. (Type I). In a certain number of cases, however, there is no appreciable change in the I.T. after fat ingestion and the presence of molecular (invisible) fats, in contradistinction to particulate fats, is immediately revealed by a diminished Total E.C. value (Type II). There seems to be little doubt that the drop in the E.C. is due to the fact that the active sites on the protein molecule have been occupied by the molecular fats, thus impairing the total E.C. of the serum. If this reasoning is correct, it should be expected that in cases of fat malabsorption both the I.T. and total E.C. values after a fatty meal should remain unchanged. This seems, in fact, to be the case (Type III). In three patients suffering from fat malabsorption, as confirmed by conventional tests, we found that the I.T. values before and after the test meal remained unchanged, obviously because of the impaired fat absorption; at the same time, the total E.C. values also remained unchanged as opposed to Type II. This behaviour is evidently due to reduced quantities of molecular fats in the serum. Hence, measurement of total E.C. before and after a fatty meal seems to constitute a test for the diagnosis of fat malabsorption. Cliti.
CJZ~WI.A4cta, II (1965)
j57p560
B. BREYER
560
et al.
ACKNOWLEDGEMENTS
We are grateful
to Dr. C. J. Cummins,
the Director
General
of Health,
New
South Wales, for permission to publish this paper. Our thanks are also due to Dr. G. C. Hughes, Medical Superintendent, Lidcombe State Hospital and Home, for supporting this investigation. We are grateful to Dr. H. Kramer, Director, Institute of Clinical Pathology and Medical Research, Lidcombe, for making available the facilities of the Institute. We also thank Mr. G. Tormay and his staff for their valuable technical assistance. REFERENCES
I B. BREYER AND 2 B. BREYER AND 3 E. MERIAN AND 4 L. STUTMAN, M. Clin. Chim.
Acta.
P. B. GOODWIN, Clin. Chim. Acta, 7 (1962) 647. F. OFNER, Clin.Chirn. Acta, 8 (1963) 173. L. FINCKER, Strasbourg Med., 13 (1962) 80. GEORGE AND L.GOTTSCH, Am.J.Med. Sk., 242 (1961) II (1965)
557-560
736.