HDL3 Cholesterol Measurement via Dextran Sulfate Precipitation
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Solution Overview
Problem
Current methods for measuring cholesterol in HDL subfractions, such as HDL2 and HDL3, often require complex operations like centrifugation, which are time-consuming and not precise enough for clinical applications.
Innovation Solution
A method using cholesterol-measuring enzymes, divalent metal salts, alkali metal salts, and dextran sulfate or its salts that allows for the measurement of cholesterol in HDL3 without separating other lipoproteins, enabling precise measurement through reactions with cholesterol ester hydrolase, oxidase, or dehydrogenase enzymes in an aqueous medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a precipitation method with separation operations is used to measure cholesterol in HDL3, then measurement precision is improved, but device complexity and time consumption increase due to centrifugation steps
Solution Approach 1:
The patent replaces mechanical separation methods (centrifugation) with a chemical precipitation method using dextran sulfate and divalent metal ions. This substitution eliminates the need for complex centrifugation operations while achieving selective precipitation of HDL3 for accurate cholesterol measurement, thus resolving the contradiction between measurement precision and operational complexity
Solution Approach 2:
The patent utilizes specific parameter conditions (pH 7.0-9.0, presence of divalent metal ions like Ca2+ or Mg2+, and controlled temperature) to optimize the precipitation reaction. By carefully controlling these parameters, the method achieves selective HDL3 precipitation without requiring mechanical separation devices, thereby maintaining measurement precision while simplifying the overall procedure
2Measurement precision
If a double separation operation is used to measure cholesterol in HDL3, then measurement precision is improved, but loss of time increases due to multiple centrifugation steps
Solution Approach 1:
The patent segments the complex double separation process into a single precipitation step using dextran sulfate and divalent metal ions. This segmentation allows simultaneous separation and measurement in one operation, eliminating the time-consuming sequential centrifugation steps while maintaining the precision needed for HDL3 cholesterol measurement
Solution Approach 2:
The patent performs preliminary preparation of the precipitation reagent system (dextran sulfate and divalent metal ions) before the measurement. This preliminary setup enables direct precipitation and measurement in a single step, avoiding the need for time-consuming centrifugation operations during the actual measurement process
3Measurement precision
If centrifugation operations are used to separate lipoproteins, then measurement precision is improved, but ease of operation deteriorates due to complex procedural steps
Solution Approach 1:
The patent replaces mechanical centrifugation with a chemical precipitation approach using dextran sulfate and divalent metal ions. This substitution maintains measurement precision through selective HDL3 precipitation while dramatically improving ease of operation by eliminating complex mechanical separation steps and reducing the procedure to simple mixing and measurement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach simplifies the measurement process, eliminating the need for centrifugation and providing precise cholesterol quantification in HDL3, which can be used to calculate HDL2 levels by subtracting HDL3 values from total HDL cholesterol measurements.
Implementation Method 1
reacting the sample with (1) a combination of a cholesterol ester hydrolase and a cholesterol oxidase
Implementation Method 2
reacting the sample with (1) a combination of a cholesterol ester hydrolase and a cholesterol oxidase
Implementation Method 3
a precipitation method comprising a step of separating HDL3 from HDL2
Data Source
AI summary
The present invention provides a method for simply and precisely measuring cholesterol in an HDL subfraction contained in a sample. This is a method for measuring cholesterol in HDL3 contained in a sample, which comprises reacting a sample with (1) a combination of a cholesterol ester hydrolase and a cholesterol oxidase or (2) a combination of a cholesterol ester hydrolase, an oxidized coenzyme and a cholesterol dehydrogenase in an aqueous medium containing: (a) a divalent metal salt; (b) an alkali metal salt selected from the group consisting of a sulfate, a nitrate, a carbonate, an acetate and a halide; and (c) dextran sulfate or a salt thereof, and measuring a substance formed or consumed in the reaction without separating and removing lipoproteins other than HDL3.