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ETP-based Activated Protein C Resistance Test
The activated protein C resistance (APCR) test is a coagulation test used in the evaluation and diagnosis of activated protein C (APC) resistance, a form of hypercoagulability. Hereditary APC resistance is usually caused by the factor V Leiden mutation, whereas acquired APC resistance has been linked to antiphospholipid antibodies, pregnancy, and estrogen therapy. APC resistance can be measured using either an activated partial thromboplastin time (aPTT)-based test or an endogenous thrombin potential (ETP)-based test. Methodology The aPTT-based APC resistance test involves a modified aPTT test performed in the presence and absence of activated protein C (APC). The ratio of these aPTT values is calculated and is called the APC sensitivity ratio (APCsr) or simply APC ratio (APCr). This ratio is inversely related to the degree of APC resistance. The ETP-based APC resistance test involves the addition of APC to a thrombin generation assay (TGA). This results in an inhibition of throm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activated Protein C Resistance
Activated protein C resistance (APCR) is a hypercoagulability (an increased tendency of the blood to clot) characterized by a lack of a response to activated protein C (APC), which normally helps prevent blood from clotting excessively. This results in an increased risk of venous thrombosis (blood clots in veins), which resulting in medical conditions such as deep vein thrombosis (usually in the leg) and pulmonary embolism (in the lung, which can cause death). The most common cause of hereditary APC resistance is factor V Leiden mutation. Presentation Associated conditions An estimated 64 percent of patients with venous thromboembolism may have APC resistance. Genetics The disorder can be acquired or inherited, the hereditary form having an autosomal dominant inheritance pattern. Pathophysiology APC (with protein S as a cofactor) degrades Factor Va and Factor VIIIa. APC resistance is the inability of protein C to cleave Factor Va and/or Factor VIIIa, which allows for longer dur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prothrombin
Thrombin (, ''fibrinogenase'', ''thrombase'', ''thrombofort'', ''topical'', ''thrombin-C'', ''tropostasin'', ''activated blood-coagulation factor II'', ''blood-coagulation factor IIa'', ''factor IIa'', ''E thrombin'', ''beta-thrombin'', ''gamma-thrombin'') is a serine protease, an enzyme that, in humans, is encoded by the ''F2'' gene. Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions. History After the description of fibrinogen and fibrin, Alexander Schmidt hypothesised the existence of an enzyme that converts fibrinogen into fibrin in 1872. Prothrombin was discovered by Pekelharing in 1894. Physiology Synthesis Thrombin is produced by the enzymatic cleavage of two sites on prothrombin by activated Factor X (Xa). The activity of factor Xa is greatl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menopausal Hormone Therapy
Hormone replacement therapy (HRT), also known as menopausal hormone therapy or postmenopausal hormone therapy, is a form of hormone therapy used to treat symptoms associated with female menopause. These symptoms can include hot flashes, vaginal atrophy, accelerated skin aging, vaginal dryness, decreased muscle mass, sexual dysfunction, and bone loss or osteoporosis. They are in large part related to the diminished levels of sex hormones that occur during menopause. Estrogens and progestogens are the main hormone drugs used in HRT. Progesterone is the main female sex hormone that occurs naturally and is also manufactured into a drug that is used in menopausal hormone therapy. Although both classes of hormones can have symptomatic benefit, progestogen is specifically added to estrogen regimens, unless the uterus has been removed, to avoid the increased risk of endometrial cancer. Unopposed estrogen therapy promotes endometrial hyperplasia and increases the risk of cancer, while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androgenic
An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes the embryological development of the primary male sex organs, and the development of male secondary sex characteristics at puberty. Androgens are synthesized in the testes, the ovaries, and the adrenal glands. Androgens increase in both males and females during puberty. The major androgen in males is testosterone. Dihydrotestosterone (DHT) and androstenedione are of equal importance in male development. DHT ''in utero'' causes differentiation of the penis, scrotum and prostate. In adulthood, DHT contributes to balding, prostate growth, and sebaceous gland activity. Although androgens are commonly thought of only as male sex hormones, females also have them, but at lower levels: they function in libido and sexual arousal. Also, andr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Progestin
A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural product, natural female sex hormone progesterone in the body. A progestin is a ''synthetic compound, synthetic'' progestogen. Progestogens are used most commonly in hormonal contraception, hormonal birth control and menopausal hormone therapy. They can also be used in the treatment of gynecological conditions, to support fertility and pregnancy, to lower sex hormone levels for various purposes, and for other indications. Progestogens are used alone or in combination with estrogen (medication), estrogens. They are available in a wide variety of drug formulation, formulations and for use by many different route of administration, routes of administration. Examples of progestogens include natural or bioidentical progesterone (medication), progesterone as well as progestins such as medroxyprogesterone acetate and norethisterone. Side ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combined Birth Control Pill
The combined oral contraceptive pill (COCP), often referred to as the birth control pill or colloquially as "the pill", is a type of birth control that is designed to be taken orally by women. The pill contains two important hormones: progestin (a synthetic form of the hormone progestogen/progesterone) and estrogen (usually ethinylestradiol and 17β estradiol). When taken correctly, it alters the menstrual cycle to eliminate ovulation and prevent pregnancy. COCPs were first approved for contraceptive use in the United States in 1960, and are a very popular form of birth control. They are used by more than 100 million women worldwide and by about 9 million women in the United States. From 2015 to 2017, 12.6% of women aged 15–49 in the US reported using COCPs, making it the second most common method of contraception in this age range (female sterilization is the most common method). Use of COCPs, however, varies widely by country, age, education, and marital status. For examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethinylestradiol
Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological disorders, and certain hormone-sensitive cancers. It is usually taken by mouth but is also used as a patch and vaginal ring. The general side effects of EE include breast tenderness and enlargement, headache, fluid retention, and nausea among others. In men, EE can additionally cause breast development, feminization in general, hypogonadism, and sexual dysfunction. Rare but serious side effects include blood clots, liver damage, and cancer of the uterus. EE is an estrogen, or an agonist of the estrogen receptors, the biological target of estrogens like estradiol. It is a synthetic derivative of estradiol, a natural estrogen, and differs from it in various ways. Compared to estradiol, EE has greatly improved bioavailability when taken by m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pregnancy
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but can also occur through assisted reproductive technology procedures. A pregnancy may end in a live birth, a miscarriage, an induced abortion, or a stillbirth. Childbirth typically occurs around 40 weeks from the start of the last menstrual period (LMP), a span known as the gestational age. This is just over nine months. Counting by fertilization age, the length is about 38 weeks. Pregnancy is "the presence of an implanted human embryo or fetus in the uterus"; implantation occurs on average 8–9 days after fertilization. An '' embryo'' is the term for the developing offspring during the first seven weeks following implantation (i.e. ten weeks' gestational age), after which the term ''fetus'' is used until birth. Signs an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estrogen (medication)
An estrogen (E) is a type of medication which is used most commonly in hormonal birth control and menopausal hormone therapy, and as part of feminizing hormone therapy for transgender women. They can also be used in the treatment of hormone-sensitive cancers like breast cancer and prostate cancer and for various other indications. Estrogens are used alone or in combination with progestogens. They are available in a wide variety of formulations and for use by many different routes of administration. Examples of estrogens include bioidentical estradiol, natural conjugated estrogens, synthetic steroidal estrogens like ethinylestradiol, and synthetic nonsteroidal estrogens like diethylstilbestrol. Estrogens are one of three types of sex hormone agonists, the others being androgens/anabolic steroids like testosterone and progestogens like progesterone. Side effects of estrogens include breast tenderness, breast enlargement, headache, nausea, fluid retention, and edema among other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombin Generation Curves With And Without Activated Protein C And With Various Oral Contraceptives With Activated Protein C
Thrombin (, ''fibrinogenase'', ''thrombase'', ''thrombofort'', ''topical'', ''thrombin-C'', ''tropostasin'', ''activated blood-coagulation factor II'', ''blood-coagulation factor IIa'', ''factor IIa'', ''E thrombin'', ''beta-thrombin'', ''gamma-thrombin'') is a serine protease, an enzyme that, in humans, is encoded by the ''F2'' gene. Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions. History After the description of fibrinogen and fibrin, Alexander Schmidt hypothesised the existence of an enzyme that converts fibrinogen into fibrin in 1872. Prothrombin was discovered by Pekelharing in 1894. Physiology Synthesis Thrombin is produced by the enzymatic cleavage of two sites on prothrombin by activated Factor X (Xa). The activity of factor Xa is greatly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ST Genesia
The ST Genesia is a fully automated commercial analyzer system for performing thrombin generation assays (TGAs) and hence for coagulation testing. It was developed by Diagnostica Stago and was introduced by the company in 2018. Traditionally, TGAs has been conducted using partially automated methods like the calibrated automated thrombogram (CAT), which was introduced in 2003. However, the CAT is performed in a 96-well plate and requires specialized technologists to be performed. Consequently, it has seen low implementation in routine laboratories and has been more limited to research settings. Lack of standardization with the CAT has also led to difficulties in study-to-study comparisons in research. It has been said that the introduction of the ST Genesia system, which will allow TGAs to be performed more easily and also shows improved reproducibility Reproducibility, also known as replicability and repeatability, is a major principle underpinning the scientific method. For t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calibrated Automated Thrombogram
The calibrated automated thrombogram (CAT or CT) is a thrombin generation assay (TGA) and global coagulation assay (GCA) which can be used as a coagulation test to assess thrombotic risk. It is the most widely used TGA. The CAT is a semi-automated test performed in a 96-well plate and requires specialized technologists to be performed. As a result, it has seen low implementation in routine laboratories and has been more limited to research settings. Lack of standardization with the CAT has also led to difficulties in study-to-study comparisons in research. However, efforts have recently been made towards standardization of the assay. An example of a specific commercial CAT is the Thrombinoscope by Thrombinoscope BV (now owned by Diagnostica Stago). The CAT can be used to measure thrombogram parameters such as the endogenous thrombin potential (ETP) and to assess activated protein C resistance (APCR). The CAT ETP-based APC resistance test is especially sensitive to estrogen-induce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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