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Antifolates
Antifolates are a class of antimetabolite medications that antagonise (that is, block) the actions of folic acid (vitamin B9). Folic acid's primary function in the body is as a cofactor to various methyltransferases involved in serine, methionine, thymidine and purine biosynthesis. Consequently, antifolates inhibit cell division, DNA/RNA synthesis and repair and protein synthesis. Some such as proguanil, pyrimethamine and trimethoprim selectively inhibit folate's actions in microbial organisms such as bacteria, protozoa and fungi. The majority of antifolates work by inhibiting dihydrofolate reductase (DHFR). Comparison of available agents Mechanism Many are primarily DHFR inhibitors, but raltitrexed is an inhibitor of thymidylate synthase, and pemetrexed inhibits both and a third enzyme. Antifolates act specifically during DNA and RNA synthesis, and thus are cytotoxic during the S-phase of the cell cycle. Thus, they have a greater toxic effect on rapidly dividing cells (such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydrofolate Reductase 1DRF
Dihydrofolic acid (conjugate base dihydrofolate) (DHF) is a folic acid ( vitamin B9) derivative which is converted to tetrahydrofolic acid by dihydrofolate reductase. Since tetrahydrofolate is needed to make both purines and pyrimidines, which are building blocks of DNA and RNA, dihydrofolate reductase is targeted by various drugs to prevent nucleic acid Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main cl ... synthesis. Interactive pathway map Further reading * References Folates {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methotrexate
Methotrexate (MTX), formerly known as amethopterin, is a chemotherapy agent and immune-system suppressant. It is used to treat cancer, autoimmune diseases, and ectopic pregnancies. Types of cancers it is used for include breast cancer, leukemia, lung cancer, lymphoma, gestational trophoblastic disease, and osteosarcoma. Types of autoimmune diseases it is used for include psoriasis, rheumatoid arthritis, and Crohn's disease. It can be given by mouth or by injection. Common side effects include nausea, feeling tired, fever, increased risk of infection, low white blood cell counts, and breakdown of the skin inside the mouth. Other side effects may include liver disease, lung disease, lymphoma, and severe skin rashes. People on long-term treatment should be regularly checked for side effects. It is not safe during breastfeeding. In those with kidney problems, lower doses may be needed. It acts by blocking the body's use of folic acid. Methotrexate was first made in 1947 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pemetrexed
Pemetrexed, sold under the brand name Alimta among others, is a chemotherapy medication for the treatment of pleural mesothelioma and non-small cell lung cancer (NSCLC).. It is available as a generic medication. Medical use In February 2004, the U.S. Food and Drug Administration (FDA) approved pemetrexed for treatment of malignant pleural mesothelioma, a type of tumor of the mesothelium, the thin layer of tissue that covers many of the internal organs, in combination with cisplatin for patients whose disease is either unresectable or who are not otherwise candidates for curative surgery. In September 2008, the FDA granted approval as a first-line treatment, in combination with cisplatin, against locally advanced and metastatic non-small cell lung cancer (NSCLC) in patients with non-squamous histology. Carboplatin Pemetrexed is also recommended in combination with carboplatin and pembrolizumab for the first-line treatment of advanced non-small cell lung cancer. However, the rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Folic Acid
Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and storage. Folate is required for the body to make DNA and RNA and metabolise amino acids necessary for cell division. As humans cannot make folate, it is required in the diet, making it an essential nutrient. It occurs naturally in many foods. The recommended adult daily intake of folate in the U.S. is 400 micrograms from foods or dietary supplements. Folate in the form of folic acid is used to treat anemia caused by folate deficiency. Folic acid is also used as a supplement by women during pregnancy to reduce the risk of neural tube defects (NTDs) in the baby. Low levels in early pregnancy are believed to be the cause of more than half of babies born with NTDs. More than 80 countries use either mandatory or voluntary fortification of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Folic Acid
Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and storage. Folate is required for the body to make DNA and RNA and metabolise amino acids necessary for cell division. As humans cannot make folate, it is required in the diet, making it an essential nutrient. It occurs naturally in many foods. The recommended adult daily intake of folate in the U.S. is 400 micrograms from foods or dietary supplements. Folate in the form of folic acid is used to treat anemia caused by folate deficiency. Folic acid is also used as a supplement by women during pregnancy to reduce the risk of neural tube defects (NTDs) in the baby. Low levels in early pregnancy are believed to be the cause of more than half of babies born with NTDs. More than 80 countries use either mandatory or voluntary fortification of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Marrow
Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adult humans, bone marrow is primarily located in the ribs, vertebrae, sternum, and bones of the pelvis. Bone marrow comprises approximately 5% of total body mass in healthy adult humans, such that a man weighing 73 kg (161 lbs) will have around 3.7 kg (8 lbs) of bone marrow. Human marrow produces approximately 500 billion blood cells per day, which join the systemic circulation via permeable vasculature sinusoids within the medullary cavity. All types of hematopoietic cells, including both myeloid and lymphoid lineages, are created in bone marrow; however, lymphoid cells must migrate to other lymphoid organs (e.g. thymus) in order to complete maturation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronchitis
Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. Symptoms include coughing up sputum, wheezing, shortness of breath, and chest pain. Bronchitis can be acute or chronic. Acute bronchitis usually has a cough that lasts around three weeks, and is also known as a chest cold. In more than 90% of cases the cause is a viral infection. These viruses may be spread through the air when people cough or by direct contact. A small number of cases are caused by a bacterial infection such as ''Mycoplasma pneumoniae'' or ''Bordetella pertussis''. Risk factors include exposure to tobacco smoke, dust, and other air pollution. Treatment of acute bronchitis typically involves rest, paracetamol (acetaminophen), and nonsteroidal anti-inflammatory drugs (NSAIDs) to help with the fever. Chronic bronchi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urinary Tract Infections
A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidney infection (pyelonephritis). Symptoms from a lower urinary tract infection include pain with urination, frequent urination, and feeling the need to urinate despite having an empty bladder. Symptoms of a kidney infection include fever and flank pain usually in addition to the symptoms of a lower UTI. Rarely the urine may appear bloody. In the very old and the very young, symptoms may be vague or non-specific. The most common cause of infection is ''Escherichia coli'', though other bacteria or fungi may sometimes be the cause. Risk factors include female anatomy, sexual intercourse, diabetes, obesity, and family history. Although sexual intercourse is a risk factor, UTIs are not classified as sexually transmitted infections (STIs). Kidney ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrimethamine
Pyrimethamine, sold under the brand name Daraprim among others, is a medication used with leucovorin (leucovorin is used to decrease side effects of pyrimethamine; it does not have intrinsic anti-parasitic activity) to treat the parasitic diseases toxoplasmosis and cystoisosporiasis. It is also used with dapsone as a second-line option to prevent ''Pneumocystis jiroveci'' pneumonia in people with HIV/AIDS. It was previously used for malaria but is no longer recommended due to resistance. Pyrimethamine is taken by mouth. Common side effects include gastrointestinal upset, severe allergic reactions, and bone marrow suppression. It should not be used by people with folate deficiency that has resulted in anemia. There is concern that it may increase the risk of cancer. While occasionally used in pregnancy it is unclear if pyrimethamine is safe for the baby. Pyrimethamine is classified as a folic acid antagonist. It works by inhibiting folic acid metabolism and therefore the maki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shigellosis
Shigellosis is an infection of the intestines caused by ''Shigella'' bacteria. Symptoms generally start one to two days after exposure and include diarrhea, fever, abdominal pain, and feeling the need to pass stools even when the bowels are empty. The diarrhea may be bloody. Symptoms typically last five to seven days and it may take several months before bowel habits return entirely to normal. Complications can include reactive arthritis, sepsis, seizures, and hemolytic uremic syndrome. Shigellosis is caused by four specific types of ''Shigella''. These are typically spread by exposure to infected feces. This can occur via contaminated food, water, or hands or sexual contact. Contamination may be spread by flies or when changing diapers (nappies). Diagnosis is by stool culture. The risk of infection can be reduced by properly washing the hands. There is no vaccine. Shigellosis usually resolves without specific treatment. Rest, and sufficient fluids by mouth, are recommended. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melioidosis
Melioidosis is an infectious disease caused by a gram-negative bacterium called ''Burkholderia pseudomallei''. Most people exposed to ''B. pseudomallei'' experience no symptoms; however, those who do experience symptoms have signs and symptoms that range from mild such as fever and skin changes, to severe with pneumonia, abscesses, and septic shock that could cause death. Approximately 10% of people with melioidosis develop symptoms that last longer than two months, termed "chronic melioidosis". Humans are infected with ''B. pseudomallei'' by contact with contaminated soil or water. The bacteria enter the body through wounds, inhalation, or ingestion. Person-to-person or animal-to-human transmission is extremely rare. The infection is constantly present in Southeast Asia particularly in northeast Thailand and northern Australia. In temperate countries such as Europe and the United States, melioidosis cases are usually imported from countries where melioidosis is endemic. The sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxoplasmosis
Toxoplasmosis is a parasitic disease caused by ''Toxoplasma gondii'', an apicomplexan. Infections with toxoplasmosis are associated with a variety of neuropsychiatric and behavioral conditions. Occasionally, people may have a few weeks or months of mild, flu-like illness such as muscle aches and tender lymph nodes. In a small number of people, eye problems may develop. In those with a weak immune system, severe symptoms such as seizures and poor coordination may occur. If a person becomes infected during pregnancy, a condition known as congenital toxoplasmosis may affect the child. Toxoplasmosis is usually spread by eating poorly cooked food that contains cysts, exposure to infected cat feces, and from an infected woman to their baby during pregnancy. Rarely, the disease may be spread by blood transfusion. It is not otherwise spread between people. The parasite is known to reproduce sexually only in the cat family. However, it can infect most types of warm-blooded animals, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
