|
Steroid Sulfatase
Steroid sulfatase (STS), or steryl-sulfatase (EC 3.1.6.2), formerly known as arylsulfatase C, is a sulfatase enzyme involved in the metabolism of steroids. It is encoded by the ''STS'' gene. Reactions This enzyme catalysis, catalyses the following chemical reaction : 3β-hydroxyandrost-5-en-17-one 3-sulfate + H2O \rightleftharpoons 3β-hydroxyandrost-5-en-17-one + sulfate Also acts on some related steryl sulfates. Function The protein encoded by this gene catalyzes the conversion of sulfated steroid precursors to the free steroid. This includes DHEA sulfate, estrone sulfate, pregnenolone sulfate, and cholesterol sulfate, all to their unconjugated forms (DHEA, estrone, pregnenolone, and cholesterol, respectively). The encoded protein is found in the endoplasmic reticulum, where it is present as a homodimer. Clinical significance A congenital deficiency in the enzyme is associated with X-linked ichthyosis, a scaly-skin disease affecting roughly 1 in every 2,000 to 6,000 mal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfatase
In biochemistry, sulfatases are a class of enzymes of the esterase class that catalyze the hydrolysis of sulfate esters into an Alcohol (chemistry), alcohol and a bisulfate: :\ce \quad \xrightarrow[\text] \quad \ce These may be found on a range of Substrate (chemistry), substrates, including steroids, carbohydrates and proteins. Sulfate esters may be formed from various alcohols and amines. In the latter case the resultant ''N''-sulfates can also be termed sulfamates. Sulfatases play important roles in the cycling of sulfur in the environment, in the degradation of sulfated glycosaminoglycans and glycolipids in the lysosome, and in remodelling sulfated glycosaminoglycans in the extracellular space. Together with sulfotransferases, sulfatases form the major catalytic machinery for the synthesis and breakage of sulfate esters. Occurrence and importance Sulfatases are found in lower and higher organisms. In higher organisms they are found in intracellular and extracellular space ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estrogenic STS And EST Activity
Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3). Estradiol, an estrane, is the most potent and prevalent. Another estrogen called estetrol (E4) is produced only during pregnancy. Estrogens are synthesized in all vertebrates and some insects. Quantitatively, estrogens circulate at lower levels than androgens in both men and women. While estrogen levels are significantly lower in males than in females, estrogens nevertheless have important physiological roles in males. Like all steroid hormones, estrogens readily diffuse across the cell membrane. Once inside the cell, they bind to and activate estrogen receptors (ERs) which in turn modulate the expression of many genes. Additi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breast Cancer
Breast cancer is a cancer that develops from breast tissue. Signs of breast cancer may include a Breast lump, lump in the breast, a change in breast shape, dimpling of the skin, Milk-rejection sign, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. In those with Metastatic breast cancer, distant spread of the disease, there may be bone pain, swollen lymph nodes, shortness of breath, or yellow skin. Risk factors for developing breast cancer include obesity, a Sedentary lifestyle, lack of physical exercise, alcohol consumption, hormone replacement therapy during menopause, ionizing radiation, an early age at Menarche, first menstruation, having children late in life (or not at all), older age, having a prior history of breast cancer, and a family history of breast cancer. About five to ten percent of cases are the result of an inherited genetic predisposition, including BRCA mutation, ''BRCA'' mutations among others. Breast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostate Cancer
Prostate cancer is the neoplasm, uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Abnormal growth of the prostate tissue is usually detected through Screening (medicine), screening tests, typically blood tests that check for prostate-specific antigen (PSA) levels. Those with high levels of PSA in their blood are at increased risk for developing prostate cancer. Diagnosis requires a prostate biopsy, biopsy of the prostate. If cancer is present, the pathologist assigns a Gleason score; a higher score represents a more dangerous tumor. Medical imaging is performed to look for cancer that has spread outside the prostate. Based on the Gleason score, PSA levels, and imaging results, a cancer case is assigned a cancer staging, stage 1 to 4. A higher stage signifies a more advanced, more dangerous disease. Most prostate tumors remain small and cause no health problems. These are managed with active surveillance of prostate cancer, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estrogen-dependent Condition
An estrogen-dependent condition can be that relating to the differentiation in the steroid sex hormone that is associated with the female reproductive system and sex characteristics. These conditions can fall under the umbrella of hypoestrogenism, hyperestrogenim, or any sensitivity to the presence of estrogen in the body. Estrogen Estrogen is a critical sex hormone for women (in conjunction with progesterone). Estrogen is responsible for all different functions in a female body, but is also seen in any gender. These functions are seen in body tracts such as the skeletal system, liver, brain and breasts. There are three different formulations of estrogen: estrone, estradiol, and estriol. These are commonly referred to as E1, E2, and E3, following the listing stated prior. These three formulations have different functions in a women's life. Estradiol (E2) is seen in the reproductive time period. Estriol (E3) is seen primarily during pregnancy. Finally, estrone (E1) is the form the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androgen-dependent Condition
An androgen-dependent condition, disease, disorder, or syndrome, is a medical condition that is, in part or full, dependent on, or is sensitive to, the presence of androgenic activity in the body. Known androgen-dependent conditions include acne Acne ( ), also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, ..., seborrhea, androgenic alopecia, hirsutism, hidradenitis suppurativa, precocious puberty in boys, hypersexuality, paraphilias, benign prostatic hyperplasia (BPH), prostate cancer, and hyperandrogenism in women such as in polycystic ovary syndrome (PCOS), congenital adrenal hyperplasia (CAH), and androgen-secreting tumors (gonadal tumor, gonadal or adrenal tumor). Such conditions may be treated with drugs with antiandrogen actions, including androgen receptor receptor antagonist, antagonists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemostasis
In biology, hemostasis or haemostasis is a process to prevent and stop bleeding, meaning to keep blood within a damaged blood vessel (the opposite of hemostasis is hemorrhage). It is the first stage of wound healing. Hemostasis involves three major steps: * vasoconstriction * temporary blockage of a hole in a damaged blood vessel by a platelet plug * blood coagulation (formation of fibrin clots) Coagulation, the changing of blood from a liquid to a gel which forms the fibrin clots, is essential to hemostasis. Intact blood vessels moderate blood's tendency to form clots. The endothelial cells of intact vessels prevent blood clotting with a heparin-like molecule and thrombomodulin, and prevent platelet aggregation with nitric oxide and prostacyclin. When endothelium of a blood vessel is damaged, the endothelial cells stop secretion of coagulation and aggregation inhibitors and instead secrete von Willebrand factor, which initiates the maintenance of hemostasis after in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interatrial Septum
The interatrial septum is the wall of tissue that separates the right and left atria of the heart. Structure The interatrial septum is a that lies between the left atrium and right atrium of the human heart. The interatrial septum lies at angle of 65 degrees from right posterior to left anterior because right atrium is located at the right side of the body while left atrium is located at the left side of the body. The interatrial septum represents the posterior wall of the right atrium. Development The interatrial septum forms during the first and second months of fetal development. Formation of the septum occurs in several stages. The first is the development of the septum primum, a crescent-shaped piece of tissue forming the initial divider between the right and left atria. Because of its crescent shape, the septum primum does not fully occlude the space between the left and right atria; the opening that remains is called the ostium primum. During fetal development, this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interventricular Septum
The interventricular septum (IVS, or ventricular septum, or during development septum inferius) is the stout wall separating the ventricle (heart), ventricles, the lower chambers of the heart, from one another. The interventricular septum is directed obliquely backward to the right and curved with the convexity toward the right ventricle; its margins correspond with the anterior interventricular sulcus, anterior and Posterior interventricular sulcus, posterior interventricular sulci. The lower part of the septum, which is the major part, is thick and muscular, and its much smaller upper part is thin and membraneous. During each cardiac cycle the interventricular septum contracts by shortening longitudinally and becoming thicker. Structure The interventricular septum is the stout wall separating the Ventricle (heart), ventricles, the lower chambers of the heart, from one another. The ventricular septum is directed obliquely backward to the right and curved with the convexity t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrhythmia
Arrhythmias, also known as cardiac arrhythmias, are irregularities in the cardiac cycle, heartbeat, including when it is too fast or too slow. Essentially, this is anything but normal sinus rhythm. A resting heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia, and a resting heart rate that is too slow – below 60 beats per minute – is called bradycardia. Some types of arrhythmias have no symptoms. Symptoms, when present, may include palpitations or feeling a pause between heartbeats. In more serious cases, there may be presyncope, lightheadedness, Syncope (medicine), passing out, shortness of breath, chest pain, or decreased level of consciousness. While most cases of arrhythmia are not serious, some predispose a person to complications such as stroke or heart failure. Others may result in cardiac arrest, sudden death. Arrhythmias are often categorized into four groups: premature heart beat, extra beats, supraventricular tachycard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrial Flutter
Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart. When it first occurs, it is usually associated with a fast heart rate and is classified as a type of supraventricular tachycardia (SVT). Atrial flutter is characterized by a sudden-onset (usually) regular abnormal heart rhythm on an electrocardiogram (ECG) in which the heart rate is fast. Symptoms may include a feeling of the heart beating too fast, too hard, or skipping beats, chest discomfort, difficulty breathing, a feeling as if one's stomach has dropped, a feeling of being light-headed, or loss of consciousness. Although this abnormal heart rhythm typically occurs in individuals with cardiovascular disease (e.g., high blood pressure, coronary artery disease, and cardiomyopathy) and diabetes mellitus, it may occur spontaneously in people with otherwise normal hearts. It is typically not a stable rhythm and often degenerates into atrial fibrillation (AF). But rar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrial Fibrillation
Atrial fibrillation (AF, AFib or A-fib) is an Heart arrhythmia, abnormal heart rhythm (arrhythmia) characterized by fibrillation, rapid and irregular beating of the Atrium (heart), atrial chambers of the heart. It often begins as short periods of abnormal cardiac cycle, beating, which become longer or continuous over time. It may also start as other forms of arrhythmia such as atrial flutter that then transform into AF. Episodes can be asymptomatic. Symptomatic episodes may involve heart palpitations, syncope (medicine), fainting, Presyncope, lightheadedness, Unconsciousness, loss of consciousness, or shortness of breath. Atrial fibrillation is associated with an increased risk of heart failure, dementia, and stroke. It is a type of supraventricular tachycardia. Atrial fibrillation frequently results from bursts of tachycardia that originate in muscle bundles extending from the Atrium (heart), atrium to the pulmonary veins. Pulmonary vein isolation by catheter ablation, trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
