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Patrick Tso, Ph.D.
Price Schedule
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Lipid, Lipoprotein and Glucose Metabolism Core
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Diabetes is defined by abnormalities in circulating metabolites; obviously glucose metabolism is impaired, but the presence of certain dyslipidemias can also lead to a predisposition for cardiovascular disease in diabetic patients. This core is capable of measuring numerous metabolic parameters in mouse models pertaining to serum lipid profiles, glucose metabolism and plasma hormones. The core is directed by Drs. Patrick Tso and David D'Alessio.
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Test Descriptions, References and Data
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Test name:
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Intestinal lipid absorption in the conscious mouse (C1051)
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Keywords:
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fistula, lymph, gastrointestinal tract, lipid, absorption
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Description:
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This procedure enables the study of the intestinal digestion, absorption
and lymphatic transport of dietary lipid in the conscious mouse. By
infusing the lipid test meal intraduadenally at a constant rate, the lymphatic
lipid output usually reaches a steady rate by the 3rd or 4th hour.
Thus, lymphatic lipid output during the 5th or 6th hour represents the amount
of lipid transported by the small intestine under steady-state conditions.
At the end of the study, both luminal as well as mucosal radioactive
lipids can be collected. Thus one can obtain a considerable amount
of information regarding the digestion, uptake and mucosal esterification
and the lymphatic transport of lipids.
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References:
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Test name:
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Lipoprotein profile (C1053)
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Keywords:
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lipoprotein, lipids, electrophoresis, agarose, agarose gel electrophoresis
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Description:
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As part of the standard lipoprotein determination, plasma lipoproteins
will be analyzed using agarose gel electrophoresis. Small aliquots
of lymph or plasma can be used for the assay. It is particularly useful
for identifying beta-VLDL and the analysis of lipoprotein classes when plasma
triglycerides are high (>300 mg/dl |
References:
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Test name:
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Lipoprotein fractionation by FPLC (C1054)
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Keywords:
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FPLC, lipoproteins, lipids, apolipoproteins
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Description:
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To obtain a more precise determination of lipids and apolipoproteins in
the different lipoprotein fractions, the lipoproteins of plasma or lymph
can be separated using Fast Protein Liquid Chromatography. This method
is sometimes preferred over ultracentrifugation as the amount of blood required
is much lower. The lipoproteins in each column fraction will be separated
by agarose electrophoresis and stained to identify VLDL remnants, LDL, apo
E-containing large HDL particles, small alpha migrating HDL and pre-beta
HDL. |
References:
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Test name:
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Metabolism of chylomicrons (C1055)
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Keywords:
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chylomicron, lipid, chylomicron remnants, intestine, apolipoproteins
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Description:
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The intestinal lymph duct and duodenum will be surgically cannulated. Chylomicrons
are harvested and sized by negative staining. A small sample will
be delipidated, and the apoprotein composition will be analyzed by polyacrylamide
gel electrophoresis. Labeled CM is injected into mice and the plasma
clearance rate is calculated as well as a determination of the uptake by
the liver. |
References:
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Test name:
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Cholesterol synthetic rate (C1056)
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Keywords:
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cholesterol, synthesis, lipids, fatty acid, sterol
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Description:
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To measure sterol synthesis rates, mice will be injected with deuterated
water i.p. One hour later, the animals are anesthetized and exsanguinated.
Tissues are removed and saponified. The amount of digitonin-precipitable
sterols will be determined and cholesterol synthesis can then be calculated. |
References:
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Test name:
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Plasma/serum concentrations of B-hydroxybutyrate (C1057), free fatty
acids (C1058) and glucose (C1071)
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Keywords:
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glucose, free fatty acid, b-hydroxybutyrate
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Description:
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Determinations of substrates (glucose, B-hydroxybutyrate and free fatty
acids) in blood will be made using specific biochemical reactions that
generate a specific color in proportion to their concentration. Reactions
will be run in microtiter plates and analyzed on a plate reader. Using
this method assays can be performed on small (5-25ul) samples of plasma or
serum. |
References:
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Test name:
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Glucose tolerance (intraperitoneal, oral) (C1070)
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Keywords:
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glucose tolerance, intraperitoneal glucose tolerance, insulin secretion,
glucose metabolism, glucose disposal
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Description:
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Mice will be fasted for 4 hours and anesthetized. A fasting blood
sample will be removed from the tail vein and a concentrated solution of
glucose injected into the abdominal cavity of the mice through a needle passed
through the abdominal skin. Blood samples will be removed from the
tail vein 5, 10, 15, 20, 25 and 30 minutes later. Samples of plasma
obtained during the test will be measured for concentrations of glucose and
insulin. |
References:
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Test name:
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Oral glucose tolerance test (C1070)
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Keywords:
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glucose tolerance, oral glucose tolerance, insulin secretion, glucose metabolism,
glucose disposal
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Description:
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Mice will be fasted for 4 hours and anesthetized. A fasting blood
sample will be removed from the tail vein and a concentrated solution of
glucose infused into the stomach of the mice through a tube passed through
the mouth. Blood samples will be removed from the tail vein at
10, 30, 60, and 120 minutes later. Samples of plasma obtained during
the test will be measured for concentrations of glucose and insulin. |
References:
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Test name:
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Insulin tolerance test (C1072)
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Keywords:
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insulin sensitivity, insulin resistance, glucose disposal, glucose disappearance,
glucose metabolism
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Description:
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Mice will be fasted for 4 hours and anesthetized. A fasting blood
sample will be removed from the tail vein and insulin (0.5mU/g) will be injected
into the abdominal cavity. Blood samples will be removed from
the tail vein 5, 10, 15, 20, 25 and 30 minutes later. samples of plasma
obtained during the test will be measured for concentrations of glucose and
insulin. |
References:
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Test name:
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Cholecystokinin (C1082)
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Keywords:
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CCK, intestine, hormone
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Description:
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This gastrointestinal hormone can be quantified by radioimmunoassay. |
References:
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Test name:
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Somatostatin in plasma or tissue extracts (C1092)
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Keywords:
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somatostatin, peptides
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Description:
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Somatostatin is measured with a radioimmunoassay that detects all of the
prosomatostatin peptides. |
References:
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Ensinck, J.W., Laschansky, E.C., Vogel, R.E., Siminowitz, D.A., Roos,B.,
Francis, B.H. Circulating prosomatostatin-derived peptides. Differential
response to food ingestion. J. Clin. Invest. 1989 May;83(5):1580-9. |
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Test name:
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Plasma GLP-1 concentrations (C1086)
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Keywords:
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GLP-1, glucagon-like peptide
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Description:
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Glucagon-like peptide 1 (GLP-1) concentrations are measured using a specific
radioimmunoassay. |
References:
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D'Alessio, D.A., Prigeon, R.L., Ensinck, J.W. Enteral enhancement of glucose
disposition by both insulin-dependent and insulin-dependent processes: A physiologic
role of Glucagon-like peptide 1. Diabetes 44:1433-1437, 1995. |
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Test name:
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Plasma GIP (C1088)
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Keywords:
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GIP, glucose-dependent insulinotropic polypeptide
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Description:
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glucose-dependent insulinotropic polypeptide
(GIP) is measured by radioimmunoassay. |
References:
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Walsh, J.H., Wong, H.C.: Radioimmunoassay of Gastrointestinal Polypeptides.
In Handbook of Experimental Pharmacology. Patrono, C., Peskar, B.A.,
Eds. Springer-Verlag, 2001, p315-350. |
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Test name:
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Plasma/serum concentrations of C-peptide (C1081), glucagon (C1085) and leptin (C1090).
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Keywords:
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C-peptide, glucagon, leptin
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Description:
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Plasma concentrations of C-peptide, glucagon and leptin are determined using
radioimmunoassay kits available fro Linco Inc. (St. Louis, MO) |
References:
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Test name:
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Insulin concentrations in plasma/serum/lymph/cerebrospinal fluid (C1089)
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Keywords:
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insulin, proinsulin, lymph, CSF
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Description:
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Concentrations of insulin in plasma or serum are determined using a sensitive
radioimmunoassay that is specific for insulin but also reacts with proinsulin.
The assay has been sensitized such that concentrations of insulin can
be determined in small (10-25 ul) aliquots of serum/plasma. The assay
has been used to detect insulin concentrations in other body fluids such as
lymph and cerebrospinal fluid. |
References:
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Test name:
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Plasma total cholesterol (C1083), HDL-cholesterol(C1083), LDL-cholesterol(1083), Plasma triglycerides (C1092),
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Keywords:
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cholesterol, lipids, fat, phospholipids, fatty acid
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Description:
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Blood samples will be collected in EDTA-containing tubes from the tails
of mice after a 4 hour fast. Plasma will be prepared from these samples
using centrifugation and the lipid levels will be determined using enzymatic
methods. The LDL-cholesterol will be estimated using the equation: (VLDL+LDL-cholesterol)
- (VLDL- triglycerides)/5. |
References:
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