68 results about "Cystatin S" patented technology

The invention provides an in-vitro detection method of human cystatin C. The method adopts a magnetic particle separation chemiluminescence immunoassay technology which is a product integrating an enzyme labeling technology, a magnetic particle separation technology and a chemiluminescence detection technology and has the advantages of high sensitivity, good specificity, good repetitiveness, and the like. The method can be used for measuring the content of cystatin C in the serum, the plasma and the urine of a person, and the indexes are mainly used for clinically evaluating the renal function and mainly used for monitoring the filtration rate of glomerulus, the renal tubular dysfunction and various secondary nephropathies.

The invention discloses a recombinant human cystatin C gene and expression and application thereof. A truncated human cystatin C gene has a nucleic acid sequence as shown as in SEQ ID NO:1; the truncated human cystatin C protein has an amino acid sequence as shown in SEQ ID NO:2. The invention uses a genetic engineering technique to express and purify a great deal of stable recombinant soluble cystatin C protein and obtains a pair of monoclonal antibodies using the protein to prepare stable cystatin C diagnostic reagents and quality control products thereof, thereby solving bottleneck problems of independent research and development of a cystatin testing reagent box.

There is a demand for improved turbidimetric immunoassays for human Cystatin C in biological samples, especially in human clinical samples of body fluids. The present invention provides a turbidimetric immunoassay method and reagent set enabling measurement of human Cystatin C by turbidimetric methods, resulting in a surprisingly stronger and faster turbidimetric signal than in the present state of the art. The increased and faster signal is accomplished by the use of new reagents and compositions, and enables shorter assay times and kinetic reading with a stronger signal, improving overall assay speed and quality. Improved robustness to lipid interference and improved linearity is achieved.

The invention discloses a recombined human cystatin-C protein with natural activity and a preparation method thereof. According to the preparation method, lots of stable recombined human cystatin-C proteins are expressed and purified by employing a gene engineering technique, and the recombined human cystatin-C proteins are cut by utilizing the protease, so that the recombined human cystatin-C protein has high natural activity. The recombined human cystatin-C protein can be used for immune preparation of monoclonal antibodies and multi-antibody blood serum, and excellent raw materials are provided for preparing stable cystatin-C detection agents and quality control products thereof.

The invention discloses a recombinant human cystatin C coding gene and an expression method. The nucleotide sequence of the coding gene is shown in SEQ ID NO:1, and the expression method of recombinant human cystatin C protein comprises the following steps that the recombinant human cystatin C coding gene is inserted into a polyclone locus of a prokaryotic expression carrier, a recombinant expression plasmid is constructed, the recombinant expression plasmid is converted to an expression host bacterium escherichia coli, and positive clone bacteria are screened out to obtain engineering bacteria; and the engineering bacteria are fermented, induced, separated and purified to obtain the recombinant human cystatin C protein. The recombinant human cystatin C coding gene provided by the invention can express the human cystatin C protein, the operation is convenient, the purity of the human cystatin C protein expressed by the coding gene reaches more than 90%, the expression efficiency is high, and no higher expression efficiency exists currently.

The invention relates to the technical field of in-vitro diagnostic reagents and particularly relates to a cystatin C detection reagent and method. The detection reagent is composed of a reagent 1 and a reagent 2. The reagent 1 comprises ammonium chloride, polyoxyethylene lauryl ether, sodium chloride, PEG 6000, a preservative and water. The reagent 2 comprises latex microspheres coated with a cystatin C monoclonal antibody, a Tris-HCl buffer solution, sucrose, gelatin, NP30, a preservative and water. The detection reagent has high detection result accuracy, a good precision, a wide linear range, good specificity, good stability and strong anti-interference ability, can be conveniently detected on a full-automatic biochemical analyzer, has a wide application range and is easy to promote.

The invention discloses a method for expressing and purifying recombinant human cystatin C proteins by using a eukaryon expression system. Because posttranslational modification and other mechanisms are lacked in a pronucleus expression system, the expressed and purified proteins have the defects of low activity and large structural difference as compared with the natural proteins, which results in that a cystatin C detection agent is difficult in the establishment process by using a monoclonal antibody prepared from Escherichia coli source recombinant cystatin C proteins. In the method, the defects of the pronucleus expression are overcome by utilizing the eukaryon expression system so as to obtain the high-activity recombinant human cystatin C protein, and a powerful basis is provided for obtaining a high-quality antibody.

The invention discloses combined application of cysteine proteinase inhibitor S (Cystatin S) and carbohydrate antigen 15-3 (CA15-3) and in particular discloses application of Cystatin S and CA15-3 in preparation of markers for diagnosing and predicting breast cancer. The invention also discloses a trapping agent of breast cancer markers and a kit comprising the trapping agent. The kit has the advantages of good specificity and high sensitivity and can be applied to early diagnosis of the breast cancer, therapeutic effect evaluation in a breast cancer treating process and monitoring of transfer and recurrence after treating the breast cancer; diagnosis results can be earlier than clinical symptoms.

The invention relates to a recombinant cystatin C protein (rhCysC) and the application of the recombinant cystatin C protein to a detection kit for detecting serum cystatin C (CysC) and belongs to thefield of in vitro diagnosis of medical immunology. According to the recombinant cystatin C protein (rhCysC) and the application of the recombinant cystatin C protein of the invention, the gene sequence of coded rhCysC, which is obtained through specially carrying out codon optimization on an escherichia coli expression system, is provided, wherein the sequence is as shown as SEQ ID NO: 2. With the sequence transferred, the expression efficiency of heterologous genes in a host bacterium can be remarkably improved. The recombinant expression method of the rhCysC has the characteristics of shortperiod, large expression quantity and low cost; the rhCysC prepared by the method can be used as an effective immunogen for the preparation of rabbit polyclonal antibodies. With the polyclonal antibodies applied to the preparation of a latex-enhanced immunoturbidimetric detection kit, the content of CysC in serum can be accurately detected. Compared with a commercially available product, the recombinant cystatin C protein (rhCysC) has better repeatability and higher accuracy, and shows a good clinical application prospect.

The invention discloses new application of cystatin S, and specifically discloses application of cystatin S to prepare a marker for diagnosing and indicating liver cancer, gastrointestinal stromal tumor, pancreas cancer, esophagus cancer or stomach cancer. The invention also discloses a trapping agent of the marker for diagnosing and indicating liver cancer, gastrointestinal stromal tumor, pancreas cancer, esophagus cancer or stomach cancer, and the trapping agent is applied to prepare a kit for diagnosing and indicating liver cancer, gastrointestinal stromal tumor, pancreas cancer, esophagus cancer or stomach cancer. The prepared kit has the advantages of being good in specificity, high in sensitivity and the like, is applicable to early diagnosis on liver cancer, gastrointestinal stromal tumor, pancreas cancer, esophagus cancer or stomach cancer, assessment on treatment effect during treatment and monitoring on metastasis and recurrence after treatment is finished.