| sick role | Behaviour patterns consistent with those expected of an individual functioning in a state of ill health. (12 Dec 1998) |
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| sick sinus syndrome | <syndrome> A disorder consisting of abnormalities of supraventricular impulse generation and conduction which produce a wide variety of intermittent rapid and slow supraventricular arrhythmias. Common symptoms include palpitations, faintness and fainting. Diagnosis is generally by 24 hour cardiac monitoring. A permanent pacemaker is indicated for those who are unresponsive to drug therapy. (27 Sep 1997) |
| sicken | 1. To make sick; to disease. "Raise this strength, and sicken that to death." (Prior) 2. To make qualmish; to nauseate; to disgust; as, to sicken the stomach. 3. To impair; to weaken. Origin: Sickened; Sickening. 1. To become sick; to fall into disease. "The judges that sat upon the jail, and those that attended, sickened upon it and died." (Bacon) 2. To be filled to disgust; to be disgusted or nauseated; to be filled with abhorrence or aversion; to be surfeited or satiated. "Mine eyes did sicken at the sight." (Shak) 3. To become disgusting or tedious. "The toiling pleasure sickens into pain." (Goldsmith) 4. To become weak; to decay; to languish. "All pleasures sicken, and all glories sink." (Pope) Source: Websters Dictionary (01 Mar 1998) |
| sicker | <chemical> To percolate, trickle, or ooze, as water through a crack. [Also written sigger, zigger, and zifhyr. Origin: AS. Sicerian. Source: Websters Dictionary (01 Mar 1998) |
| sickish | 1. Somewhat sick or diseased. 2. Somewhat sickening; as, a sickish taste. Sick"ishly, Sick"ishness. Source: Websters Dictionary (01 Mar 1998) |
| sicklaemia | Presence of sickle-or crescent-shaped erythrocytes in peripheral blood; seen in sickle cell anaemia and sickle cell trait. (05 Mar 2000) |
| sickle | 1. A reaping instrument consisting of a steel blade curved into the form of a hook, and having a handle fitted on a tang. The sickle has one side of the blade notched, so as always to sharpen with a serrated edge. Cf. Reaping hook, under Reap. "When corn has once felt the sickle, it has no more benefit from the sunshine." (Shak) 2. <astronomy> A group of stars in the constellation Leo. <botany> Sickle pod, a kind of rock cress (Arabis Canadensis) having very long curved pods. Origin: OE. Sikel, AS. Sicol; akin to D. Sikkel, G. Sichel, OHG. Sihhila, Dan. Segel, segl, L. Secula, fr. Secare to cut; or perhaps from L. Secula. See Saw a cutting instrument. Source: Websters Dictionary (01 Mar 1998) |
| sickle cell | <haematology, pathology> An erythrocyte that changes from the normal discoid shape to a sickled shape when the oxygen tension is low. The pesence of these cells indicates that the patient is homozygotes for the allele that codes for haemoglobin S and that the patient has sickle cell anaemia. (18 Nov 1997) |
| sickle cell anaemia | <haematology> Disease common in races of people from areas in which malaria is endemic. The cause is a point mutation in the allele that codes for the beta chain of haemoglobin with a substitution of (valine for glutamic acid at position 6. The defective haemoglobin (HbS) crystallizes readily at low oxygen tension. In consequence, erythrocytes from homozygotes change from the normal discoid shape to a sickled shape when the oxygen tension is low and these sickled cells become trapped in capillaries or damaged in transit, leading to severe anaemia. In heterozygotes, the disadvantages of the abnormal haemoglobin are apparently outweighed by increased resistance to Plasmodium falciparum malaria, probably because parasitised cells tend to sickle and are then removed from circulation. Symptoms include joint pain, acute abdominal pain, and ulcerations of the lower extremities. Origin: Gr. Haima = blood (18 Nov 1997) |
| sickle cell anaemia: bone manifestations | <radiology> 8-13% of blacks carry sickling factor, symptoms: chronic ulcers, pain crises, many infections, priapism X-ray findings: deossification due to marrow hyperplasia, decreased bone density in skull with widened diploe, H-shaped vertebrae or fish vertebrae, rib notching, thrombosis and infarction, avascular necrosis, especially femoral head, periosteal treatmentn (bone within bone), secondary osteomyelitis, Staph. Aureus greater than Salmonella, dactylitis = hand foot syndrome, growth effects, bone shortening secondary to diminished blood supply, death less than 40y (12 Dec 1998) |
| sickle cell C disease | A disease resulting from abnormal sickle-shaped erythrocytes (containing haemoglobin C and S) which appear in response to a lowering of the partial pressure of oxygen; characterised by anaemia, crises due to haemolysis or vascular occlusion, chronic leg ulcers and bone deformities, and infarcts of bone or of the spleen. (05 Mar 2000) |
| sickle cell crisis | <haematology> Disease common in races of people from areas in which malaria is endemic. The cause is a point mutation in the allele that codes for the beta chain of haemoglobin with a substitution of (valine for glutamic acid at position 6. The defective haemoglobin (HbS) crystallizes readily at low oxygen tension. In consequence, erythrocytes from homozygotes change from the normal discoid shape to a sickled shape when the oxygen tension is low and these sickled cells become trapped in capillaries or damaged in transit, leading to severe anaemia. In heterozygotes, the disadvantages of the abnormal haemoglobin are apparently outweighed by increased resistance to Plasmodium falciparum malaria, probably because parasitised cells tend to sickle and are then removed from circulation. Symptoms include joint pain, acute abdominal pain, and ulcerations of the lower extremities. Origin: Gr. Haima = blood (18 Nov 1997) |
| sickle cell dactylitis | <syndrome> Recurrent painful swelling of the hands and feet occurring in infants and young children with sickle cell anaemia. Synonym: sickle cell dactylitis. (05 Mar 2000) |
| sickle cell disease | <haematology> Disease common in races of people from areas in which malaria is endemic. The cause is a point mutation in the allele that codes for the beta chain of haemoglobin with a substitution of (valine for glutamic acid at position 6. The defective haemoglobin (HbS) crystallizes readily at low oxygen tension. In consequence, erythrocytes from homozygotes change from the normal discoid shape to a sickled shape when the oxygen tension is low and these sickled cells become trapped in capillaries or damaged in transit, leading to severe anaemia. In heterozygotes, the disadvantages of the abnormal haemoglobin are apparently outweighed by increased resistance to Plasmodium falciparum malaria, probably because parasitised cells tend to sickle and are then removed from circulation. Symptoms include joint pain, acute abdominal pain, and ulcerations of the lower extremities. Origin: Gr. Haima = blood (18 Nov 1997) |
| sickle cell haemoglobin | <haematology> Haemoglobin S is an abnormal version of the protein haemoglobin. The sixth amino acid of the normal beta chain, glutamic acid, is replaced by valine with gluconic acid. This mutation causes the red blood cell to take on a sickle shape, and is the cause of the sickle cell trait condition (when the individual is heterozygous for this mutant haemoglobin) and the disease of sickle cell anaemia (when the individual is homozygous for this mutant haemoglobin). (09 Oct 1997) |