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62-494: SCA may refer to: Biology and health [ edit ] Sickle cell disease , also known as sickle cell anaemia Spinocerebellar ataxia , a neurological condition Statistical coupling analysis , a method to identify covarying pairs of amino acids in protein multiple sequence alignments Sudden cardiac arrest , a condition in which the heart suddenly stops beating, leading to sudden cardiac death Superior cerebellar artery ,

124-557: A country grouping Southern Control Area , a Canadian airspace designation Soviet Central Asia Space Centre Australia Organizations [ edit ] Bureau of South and Central Asian Affairs , in the U.S. Department of State Sabah Chinese Association Sarawak Chinese Association Schuylkill Canal Association , an organization that maintains a section of historical canal in Pennsylvania Scottish Canoe Association ,

186-905: A Swedish hygiene products and paper manufacturer Computing [ edit ] SCA (computer virus) , an Amiga virus referencing the Swiss Cracking Association Service Component Architecture Side-channel attack , in cryptography Single Connector Attachment or Single Connection Attach, an 80-pin SCSI storage interface Software Communications Architecture , in Software-Defined Radio (SDR) Static code analysis Strong customer authentication Software Composition Analysis Locations [ edit ] Seoul Capital Area , Korea Singapore Changi Airport South and Central America ,

248-559: A biconcave disc shape, which allows the cells to deform to pass through capillaries. In sickle cell disease, low oxygen tension promotes red blood cell sickling and repeated episodes of sickling damage the cell membrane and decrease the cell's elasticity. These cells fail to return to normal shape when normal oxygen tension is restored. As a consequence, these rigid blood cells are unable to deform as they pass through narrow capillaries, leading to vessel occlusion and ischaemia . Cells which have become sickled are detected as they pass through

310-517: A blood transfusion. Sickle cell anaemia can lead to various complications including: Hemoglobin is an oxygen-binding protein, found in erythrocytes , which transports oxygen from the lungs (or in the fetus, from the placenta) to the tissues. Each molecule of hemoglobin comprises 4 protein subunits, referred to as globins . Normally, humans have:- β-globin is encoded by the HBB gene on human chromosome 11 ; mutations in this gene produce variants of

372-565: A business advantage that is preserved over long term USC School of Cinematic Arts , University of Southern California, United States Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title SCA . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=SCA&oldid=1222620171 " Category : Disambiguation pages Hidden categories: Short description

434-463: A carrier's red blood cells; another is that a carrier's red cells show signs of damage when infected, and are detected and destroyed as they pass through the spleen. Under conditions of low oxygen concentration, HBS polymerises to form long strands within the red blood cell (RBC). These strands distort the shape of the cell and after a few seconds cause it to adopt an abnormal, inflexible sickle-like shape. This process reverses when oxygen concentration

496-441: A major blood supplier to the cerebellum Commercial entities [ edit ] Sebastian Conran Associates , a British product and brand development consultancy Sony Corporation of America , holding company for Sony's American companies Southern Cross Austereo , an Australian media company Supercheap Auto , an Australian automotive parts and accessories retailer SCA (company) ( Svenska Cellulosa Aktiebolaget ),

558-433: A prenatal screening questionnaire which includes, among other things, a consideration of health issues in the child's parents and close relatives. During pregnancy, genetic testing can be done on either a blood sample from the fetus or a sample of amniotic fluid . During the first trimester of pregnancy, chorionic villus sampling (CVS) is also a technique used for SCD prenatal diagnosis. A routine heel prick test , in which

620-445: A prior stroke event, it also reduces the risk of recurrent stroke and additional silent strokes. Transcranial Doppler ultrasound (TCD) can detect children with sickle cell that have a high risk for stroke. The ultrasound test detects blood vessels partially obstructed by sickle cells by measuring the rate of blood into the brain, as blood flow velocity is inversely related to arterial diameter, and consequently, high blood-flow velocity

682-467: A routine part of treatment of vaso-occlusive crises but the evidence about the most effective route, amount and type of fluid replacement remains uncertain. In 2019, Crizanlizumab , a monoclonal antibody target towards p-selectin was approved in the United States to reduce the frequency of vaso-occlusive crisis in those 16 years and older. Management is similar to vaso-occlusive crisis, with

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744-462: A small sample of blood is collected a few days after birth, is used to check conclusively for SCD as well as other inherited conditions. Where SCD is suspected, a number of tests can be used. Often a simpler, cheaper test is applied first with a more complex test such as DNA analysis used to confirm a positive result. Two tests which are specific for SCD: Tests which can be used for SCD as well as for other hemoglobinopathies: Genetic counselling

806-400: A technique to encourage deep breathing to minimise the development of atelectasis , is recommended. Although it is not always clear what sets off a VOC, anything which causes blood vessels to constrict is a potential trigger. This includes physical or mental stress , cold, and dehydration . " After HbS deoxygenates in the capillaries, it takes some time (seconds) for HbS polymerization and

868-399: Is a single nucleotide mutation of the β-globin gene, which results in glutamate being substituted by valine at position 6 of the β-globin chain. Hemoglobin S with this mutation is referred to as HbS, as opposed to the normal adult HbA. Under conditions of normal oxygen concentration this causes no apparent effects on the structure of haemoglobin or its ability to transport oxygen around

930-668: Is abnormal; erythropoiesis generates a mixture of normal HbA and sickle HbS. The person has very few if any symptoms of sickle cell disease but carries the gene and can pass it on to their children. Sickle cell disease has an autosomal recessive pattern of inheritance from parents. Both copies of the affected gene must carry the same mutation ( homozygous condition) for a person to be affected by an autosomal recessive disorder. An affected person usually has unaffected parents who each carry one mutated gene and one normal gene ( heterozygous condition) and are referred to as genetic carriers ; they may not have any symptoms. When both parents have

992-455: Is also possible during pregnancy. The care of people with sickle cell disease may include infection prevention with vaccination and antibiotics , high fluid intake, folic acid supplementation, and pain medication . Other measures may include blood transfusion and the medication hydroxycarbamide (hydroxyurea). In 2023, new gene therapies were approved involving the genetic modification and replacement of blood forming stem cells in

1054-474: Is between 58 and 66 years. All the major organs are affected by sickle cell disease. The liver, heart, kidneys, gallbladder, eyes, bones, and joints also can suffer damage from the abnormal functions of the sickle cells, and their inability to flow through the small blood vessels correctly. Sickle cell disease occurs when a person inherits two abnormal copies of the β-globin gene that makes haemoglobin, one from each parent. Several subtypes exist, depending on

1116-534: Is caused by a VOC which affects the lungs, possibly triggered by infection or by emboli which have circulated from other organs. Symptoms include wheezing, chest pain, fever, pulmonary infiltrate (visible on x-ray), and hypoxemia . After sickling crisis (see above) it is the second-most common cause of hospitalization and it accounts for about 25% of deaths in patients with SCD. Most cases present with vaso-occlusive crises, and then develop acute chest syndrome. Aplastic crises are instances of an acute worsening of

1178-735: Is correlated with narrowing of the arteries. In 2002, the National Institute of Health (NIH) issued a statement recommending that children with sickle cell get the Transcranial Doppler ultrasound screen annually, and in 2014, a panel of experts convened by the NIH issued guidelines reiterating the same recommendation. One review of medical records, by hematologist Dr. Julie Kanter at the University of Alabama at Birmingham, showed that on average only 48.4 per cent of children in

1240-470: Is different from Wikidata All article disambiguation pages All disambiguation pages Sickle cell disease Sickle cell disease ( SCD ), also simply called sickle cell , is a group of hemoglobin-related blood disorders that are typically inherited . The most common type is known as sickle cell anemia . Sickle cell anemia results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells . This leads to

1302-538: Is either absent or very small and the benefits likely outweigh the risks. Voxelotor was approved in the United States in 2019, to increase hemoglobin levels in people with SCD. However, following an increased risk of vaso-occlusive seizures and death observed in registries and clinical trials, the European Medicines Agency suspended marketing authorization in September 2024, following which

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1364-432: Is most prevalent in areas which have historically been associated with endemic malaria . The sickle cell trait provides a carrier with a survival advantage against malaria fatality over people with normal hemoglobin in regions where malaria is endemic. Infection with the malaria parasite affects asymptomatic carriers of the abnormal hemoglobin gene differently from patients with full SCD. Carriers (heterozygous for

1426-425: Is of little consequence, but the shortened red cell life of SCD patients results in an abrupt, life-threatening situation. Reticulocyte count drops dramatically during the disease (causing reticulocytopenia ), red cell production lapses, and the rapid destruction of existing red cells leads to acute and severe anemia. This crisis takes four to seven days to resolve. Most patients can be managed supportively; some need

1488-548: Is raised and the cells resume their normal biconcave disc shape. If sickling takes place in the venous system, after blood has passed through the capillaries, it has no effect on the organs and the RBCs can unsickle when they become oxygenated in the lungs. Repeated switching between sickle and normal shapes damages the membrane of the RBC so that it eventually becomes permanently sickled. Normal red blood cells are quite elastic and have

1550-479: Is recommended but the effectiveness of vitamin D supplementation remains uncertain. L-glutamine use was supported by the FDA starting at the age of five, as it decreases complications. From birth to five years of age, penicillin daily, due to the immature immune system that makes them more prone to early childhood illnesses, is recommended. Dietary supplementation of folic acid had been previously recommended by

1612-401: Is sickle-shaped red blood cells that obstruct capillaries and restrict blood flow to an organ, resulting in ischaemia , pain , necrosis , and often organ damage. The frequency, severity, and duration of these crises vary considerably. Painful crises are treated with hydration, analgesics , and blood transfusion ; pain management requires opioid drug administration at regular intervals until

1674-432: Is the process by which people with a hereditary disorder are advised of the probability of transmitting it and the ways in which this may be prevented or ameliorated. People who are known carriers of the disease or at risk of having a child with sickle cell anemia may undergo genetic counseling . Genetic counselors work with families to discuss the benefits, limitations, and logistics of genetic testing options as well as

1736-561: The Mediterranean , India , and the Middle East . Malaria was historically endemic to southern Europe, but it was declared eradicated in the mid-20th century, with the exception of rare sporadic cases. The malaria parasite has a complex lifecycle and spends part of it in red blood cells. There are two mechanisms which protect sickle cell carriers from malaria. One is that the parasite is hindered from growing and reproducing in

1798-425: The spleen's filter mechanism , causing the spleen to swell and fill with blood. The accumulation of red blood cells in the spleen results in a sudden drop in circulating hemoglobin and potentially life-threatening anemia. Symptoms include pain on the left side, swollen spleen (which can be detected by palpation ), fatigue, dizziness, irritability, rapid heartbeat, or pale skin. It most commonly affects young children,

1860-667: The Egyptian antiquities service Supreme Court of Albania , the court of last resort in the Republic of Albania Swedish Committee for Afghanistan Swiss Cricket Association Sydney Catchment Authority Sydney College of the Arts Other [ edit ] McNamara–O'Hara Service Contract Act Senate Constitutional Amendment , the formal name for a type of California ballot proposition Shuttle Carrier Aircraft , two Boeing 747 aircraft modified to transport

1922-686: The Space Shuttle Small craft advisory Solar collector array , a type of solar thermal collector Spectrum continuation analysis Stored Communications Act , Title II of the US Electronic Communications Privacy Act of 1986 Subsidiary communications authority , the Federal Communications Commission's name for subcarrier channels transmitted on a broadcast FM station Sustainable competitive advantage ,

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1984-540: The US with sickle cell get the recommended ultrasound test. A 1994 NIH study showed that children at risk for strokes who received blood transfusions had an annual stroke rate of less than 1 per cent, whereas those children who did not receive blood transfusions had a 10 per cent stroke rate per year. (Also see 1998 study in the New England Journal of Medicine . ) In addition to ultrasounds and blood transfusions,

2046-602: The WHO. A 2016 Cochrane review of its use found "the effect of supplementation on anaemia and any symptoms of anaemia remains unclear" due to a lack of medical evidence. Hydroxyurea , also known as hydroxycarbamide , probably reduces the frequency of painful episodes and the risk of life-threatening illness or death but there is currently insufficient evidence regarding the risk of adverse effects. Hydroxyurea may be more effective than transfusion and chelation combined in terms of pain, life-threatening illness and risk of death. It

2108-712: The above organization Society for Cultural Anthropology , a professional association for cultural anthropologists Student Catholic Action , a religious student organization in the Philippines Student Conservation Association , a non-profit conservation service organization in the United States Suez Canal Authority , a state-owned authority which owns and maintains the Suez Canal Supreme Council of Antiquities ,

2170-424: The addition of antibiotics (usually a quinolone or macrolide, since cell wall-deficient ["atypical"] bacteria are thought to contribute to the syndrome), oxygen supplementation for hypoxia , and close observation. In the absence of high quality evidence regarding the effectiveness of antibiotics for acute chest syndrome in people with sickle cell disease, there is no standard antibiotic treatment as of 2019. Should

2232-436: The body. However, the deoxy form of HbS has an exposed hydrophobic patch which causes HbS molecules to join to form long inflexible chains. Under conditions of low oxygen concentration in the bloodstream, such as exercise, stress, altitude or dehydration, HbS polymerization forms fibrous precipitates within the red blood cell. In people homozygous for the sickle cell mutation, the presence of long-chain polymers of HbS distort

2294-523: The bone marrow. As of 2021 , SCD is estimated to affect about 7.7 million people worldwide, directly causing 34,000 annual deaths and a contributory factor to a further 376,000 deaths. About 80% of sickle cell disease cases are believed to occur in Sub-Saharan Africa . It also occurs to a lesser degree in parts of India , Southern Europe , West Asia , North Africa and among people of African origin (sub-Saharan) living in other parts of

2356-482: The crisis has settled. For milder crises, a subgroup of patients manages on nonsteroidal anti-inflammatory drugs such as diclofenac or naproxen . For more severe crises, most patients require inpatient management for intravenous opioids; patient-controlled analgesia devices are commonly used in this setting. Vaso-occlusive crisis involving organs such as the penis or lungs are considered an emergency and treated with red blood cell transfusions. Incentive spirometry ,

2418-402: The exact mutation in each haemoglobin gene. An attack can be set off by temperature changes, stress, dehydration , and high altitude. A person with a single abnormal copy does not usually have symptoms and is said to have sickle cell trait . Such people are also referred to as carriers . Diagnosis is by a blood test , and some countries test all babies at birth for the disease. Diagnosis

2480-490: The frequency of crisis events. Sickle cell disease may lead to various acute and chronic complications , several of which have a high mortality rate. When SCD presents within the first year of life, the most common problem is an episode of pain and swelling in the child's hands and feet, known as dactylitis or "hand-foot syndrome." Pallor , jaundice , and fatigue can also be early signs due to anaemia resulting from sickle cell disease. Among children older than 2 years,

2542-501: The frequency, severity, and duration of these crises vary tremendously. Painful crises are treated symptomatically with pain medications ; pain management requires opioid drug administration at regular intervals until the crisis has settled. For milder crises, a subgroup of patients manages on NSAIDs (such as diclofenac or naproxen ). For more severe crises, most patients require inpatient management for intravenous opioids. Extra fluids, administered either orally or intravenously, are

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2604-453: The gene) who catch malaria are less likely to suffer from severe symptoms than people with normal hemogolobin. SCD patients (homozygous for the gene) are similarly less likely to become infected with malaria; however once infected they are more likely to develop severe and life-threatening anemia. The impact of sickle cell anemia on malaria immunity illustrates some evolutionary trade-offs that have occurred because of endemic malaria. Although

2666-401: The inexpensive generic drug hydroxyurea can reduce the risk of irreversible organ and brain damage. Guidelines from NIH published in 2014, state that all children and adolescents should take hydroxyurea, as should adults with serious complications or three or more pain crises in a year. Most people with sickle cell disease have intensely painful episodes called vaso-occlusive crises. However,

2728-521: The manufacturer, Pfizer , withdrew it from the market worldwide. Blood transfusions are often used in the management of sickle cell disease in acute cases and to prevent complications by decreasing the number of red blood cells (RBCs) that can sickle by adding normal red blood cells. In children, preventive RBC transfusion therapy has been shown to reduce the risk of first stroke or silent stroke when transcranial Doppler ultrasonography shows abnormal cerebral blood flow. In those who have sustained

2790-432: The median age of first occurrence is 1.4 years. By the age of 5 years repeated instances of sequestration cause scarring and eventual atrophy of the spleen . Treatment is supportive, with blood transfusion if hemoglobin levels fall too low. Full or partial splenectomy may be necessary. Long term consequences of a loss of spleen function are increased susceptibility to bacterial infections . Acute chest syndrome

2852-442: The most frequent initial presentation is a painful event of generalized or variable type, and a slightly less common version appears as an event of acute chest pain. Dactylitis rarely or never occurs in children older than 2 years. Also termed "sickle cell crisis" or "sickling crisis", the vaso-occlusive crisis (VOC) manifests principally as extreme pain, most often affecting the chest, back, legs and/or arms. The underlying cause

2914-551: The national governing body for paddlesports in Scotland Screen Composers of America , an organization co-founded by Jeff Alexander Secular Coalition for America Sexual Compulsives Anonymous Société en commandite par actions , a type of corporation in France Society for Creative Anachronism , an international living history group SCA armoured combat , a combat sport developed by

2976-424: The patient's baseline anaemia, producing pale appearance , fast heart rate , and fatigue. This crisis is normally triggered by parvovirus B19 , which directly affects production of red blood cells by invading the red cell precursors and multiplying in and destroying them. Parvovirus infection almost completely prevents red blood cell production for two to three days (red cell aplasia). In normal individuals, this

3038-591: The potential impact of testing and test results on the individual. Counselling is best given before a child is conceived, and a number of possible courses could be suggested. These include adoption, the use of eggs or sperm from a healthy donor, and in-vitro fertilisation (IVF) when combined with pre-implantation genetic diagnosis of the embryos. Treatment involves a number of measures. While it has been historically recommended that people with sickle cell disease avoid exercise, regular exercise may benefit people. Dehydration should be avoided. A diet high in calcium

3100-440: The protein which are implicated with abnormal hemoglobins . The mutation which causes sickle cell disease results in an abnormal hemoglobin known as hemoglobin S (HbS), which replaces HbA in adults. The human genome contains a pair of genes for β-globin; in people with sickle cell disease, both genes are affected and the erythropoietic cells in the bone marrow will only create HbS. In people with sickle cell trait , only one gene

3162-536: The pulmonary infiltrate worsen or the oxygen requirements increase, simple blood transfusion or exchange transfusion is indicated. The latter involves the exchange of a significant portion of the person's red cell mass for normal red cells, which decreases the level of haemoglobin S in the patient's blood. However, there is currently uncertain evidence about the possible benefits or harms of blood transfusion for acute chest syndrome in people with sickle cell disease. Society for Cultural Anthropology The society

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3224-659: The red blood cells adopting an abnormal sickle -like shape under certain circumstances; with this shape, they are unable to deform as they pass through capillaries , causing blockages. Problems in sickle cell disease typically begin around 5 to 6 months of age. A number of health problems may develop, such as attacks of pain (known as a sickle cell crisis ) in joints, anemia , swelling in the hands and feet, bacterial infections , dizziness and stroke . The probability of severe symptoms, including long-term pain, increases with age. Without treatment, people with SCD rarely reach adulthood but with good healthcare, median life expectancy

3286-439: The release of free heme into the bloodstream exceeding the capacity of the body's protective mechanisms. Although heme is an essential component of hemoglobin, it is also a potent oxidative molecule. Free heme is also an alarmin - a signal of tissue damage or infection, which triggers defensive responses in the body and increases the risk of inflammation and vaso-occlusive events. Checking for SCD begins during pregnancy, with

3348-482: The shape of the red blood cell from a smooth, doughnut -like shape to the sickle shape, making it fragile and susceptible to blocking or breaking within capillaries . In people heterozygous for HbS ( carriers of sickle cell disease), the polymerisation problems are minor because the normal allele can produce half of the haemoglobin. Sickle cell carriers have symptoms only if they are deprived of oxygen (for example, at altitude) or while severely dehydrated . SCD

3410-431: The shorter life expectancy for those with the homozygous condition would tend to disfavour the trait's survival, the trait is preserved in malaria-prone regions because of the benefits provided by the heterozygous form; an example of natural selection. Due to the adaptive advantage of the heterozygote, the disease is still prevalent, especially among people with recent ancestry in malaria-stricken areas, such as Africa ,

3472-590: The sickle cell trait, any given child has a 25% chance of sickle cell disease; a 25% chance of no sickle cell alleles, and a 50% chance of the heterozygous condition (see diagram). There are several different haplotypes of the sickle cell gene mutation, indicating that it probably arose spontaneously in different geographic areas. The variants are known as Cameroon, Senegal, Benin, Bantu, and Saudi-Asian. These are clinically important because some are associated with higher HbF levels, e.g., Senegal and Saudi-Asian variants, and tend to have milder disease. The gene defect

3534-406: The spleen and are destroyed. In young children with SCD, the accumulation of sickled cells in the spleen can result in splenic sequestration crisis. In this, the spleen becomes engorged with blood, depriving the general circulation of blood cells and leading to severe anemia. The spleen initially becomes noticeably swollen but the lack of a healthy blood flow through the organ culminates in scarring of

3596-533: The spleen tissues and eventually death of the organ, generally before the age of 5 years. The actual anaemia of the illness is caused by haemolysis , the destruction of the red cells, because of their shape. Although the bone marrow attempts to compensate by creating new red cells, it does not match the rate of destruction. Healthy red blood cells typically function for 90–120 days, but sickled cells only last 10–20 days. The rapid breakdown of RBC's in SCD results in

3658-415: The subsequent flexible-to-rigid transformation. If the transit time of RBC through the microvasculature is longer than the polymerization time, sickled RBC will lodge in the microvasculature. " The spleen is especially prone to damage in SCD due to its role as a blood filter. A splenic sequestration crisis, also known as a spleen crisis, is a medical emergency that occurs when sickled red blood cells block

3720-441: The world. The condition was first described in the medical literature by American physician James B. Herrick in 1910. In 1949, its genetic transmission was determined by E. A. Beet and J. V. Neel. In 1954, it was established that carriers of the abnormal gene are some degree protected against malaria . Signs of sickle cell disease usually begin in early childhood. The severity of symptoms can vary from person to person, as can

3782-472: Was created during the "interpretive thrust" of the 1980s, during a period of internal critique and experimentation in American anthropology. Since 1986, it has published the quarterly journal Cultural Anthropology , which is currently edited by Dominic Boyer , James Faubion , and Cymene Howe . Cultural Anthropology is one of the top ten highest ranked journals in the field of anthropology In 2014,

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3844-479: Was the first approved drug for the treatment of sickle cell anaemia, and was shown to decrease the number and severity of attacks in 1995 and shown to possibly increase survival time in a study in 2003. This is achieved, in part, by reactivating fetal haemoglobin production in place of the haemoglobin S that causes sickle cell anaemia. Hydroxyurea had previously been used as a chemotherapy agent, and some concern exists that long-term use may be harmful, but this risk

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