| juvenile haemangiofibroma | <oncology, tumour> A benign tumour of the posterior nasopharynx that is most common in adolescent boys. Symptoms repeated epistaxis, nasal congestion, nasal discharge and hearing loss. A skull X-ray or a CT scan of the head can confirm the presence of an angiofibroma. Treatment may include the surgical removal of the lesion if it is enlarging or blocking the airway. (27 Sep 1997) |
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| juvenile hormone | <endocrinology> A hormone found in insects which affects the balance between mature and juvenile attributes of certain tissues at each moult. In particular, the imaginal discs of many larval insects only develop into adult wings, sexual organs or limbs when blood juvenile hormone levels fall below a threshold level. There is a complex interaction between juvenile hormone and ecdysone. Synthetic analogues of JH include farnesol and methoprene, which have been tested for insecticide potential (known, with diflubenzuron, as Insect Growth Regulators, IGRs. See: chitin). (18 Nov 1997) |
| juvenile hormone esterase | <enzyme> Amino acid sequence has been determined Registry number: EC 3.1.1.- Synonym: jh esterase, insect jhe (26 Jun 1999) |
| juvenile hormones | Compounds, either natural or synthetic, which block development of the growing insect. (12 Dec 1998) |
| juvenile hyalin fibromatosis | A rare recessively inherited deforming disorder of head, neck, and generalised cutaneous nodules or tumours in children with normal mentality; the lesions consist of fibroblasts separated by an eosinophilic hyalin stroma composed mostly of glycosaminoglycans. Synonym: systemic hyalinosis. (05 Mar 2000) |
| juvenile kyphosis | Osteochondrosis of the vertebral epiphyses in children. (12 Dec 1998) |
| juvenile muscular atrophy | Slowly progressive proximal muscular weakness and wasting, beginning in childhood, caused by degeneration of motor neurons in the anterior horns of the spinal cord; onset usually between 2 and 17 years of age; usually autosomal recessive inheritance. Synonym: juvenile muscular atrophy, Kugelberg-Welander disease, Wohlfart-Kugelberg-Welander disease. (05 Mar 2000) |
| juvenile myoclonic epilepsy | An epilepsy syndrome typically beginning in early adolescence, and characterised by early morning myoclonic jerks that may progress into a generalised tonic-clonic seizure. A genetic disorder: some families have had gene linkage to chromosome-6. The EEG is characterised by generalised polyspike and wave discharges at 4-6 Hz. (05 Mar 2000) |
| juvenile onset diabetes | A form of diabetes which has its onset in childhood. Also referred to as type I diabetes, juvenile onset diabetes or insulin-dependent diabetes. The exact cause is unknown but genetic factors seem to play a major role. Symptoms include excessive thirst, increased urination, weight loss (despite increased appetite), nausea, vomiting, fatigue and absent menstruation. Treatment includes education and regular insulin therapy. See: insulin-dependent diabetes mellitus (22 Sep 2002) |
| juvenile palmo-plantar fibromatosis | Fibromatosis that occurs in children from birth to adolescence as a single poorly demarcated nodule of the thenar or hypothenar eminence or overlying the calcaneus of the mid-sole. (05 Mar 2000) |
| juvenile papillomatosis | A form of fibrocystic disease of the breast in young women, with florid and sclerosing adenosis that microscopically may suggest carcinoma. (05 Mar 2000) |
| juvenile pattern | A precordial T-wave inversion, sometimes with J-ST elevations in an electrocardiogram, resembling that seen in normal children, which occurs as a normal variant in some adults, especially blacks, and especially in leads V1, V2, and V3. (05 Mar 2000) |
| juvenile pelvis | A pelvis justo minor in which the bones are slender. (05 Mar 2000) |
| juvenile periodontitis | A degenerative periodontal disease of adolescents in which the periodontal destruction is out of proportion to the local irritating factors present on the adjacent teeth; inflammatory changes become superimposed, and bone loss, migration, and extrusion are observed. Two forms are recognised: 1) localised, in which the destruction is limited to the incisors and first molars; 2) generalised, involving all of the teeth. Synonym: periodontosis. (05 Mar 2000) |
| juvenile polyp | A smoothly rounded mucosal hamartoma of the large bowel, which may be multiple and cause rectal bleeding, especially in the first decade of life; it is not precancerous. Synonym: retention polyp. (05 Mar 2000) |