Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0241981 (loss of balance)
452 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 27-year-old woman presented with a history of loss of balance and deafness in the left ear for 2 weeks. Computed tomography and arteriography demonstrated a giant aneurysm 49 mm in diameter in the posterior cranial fossa. Surgical removal of the aneurysm was unsuccessful.
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PMID:Giant intracranial aneurysm. A case report. 378 85

Streptococcus suis has been identified as the most common cause of meningitis in adults in Hong Kong. The disease is characterized by occupational exposure to pigs or pork. It occurs in summer, and is associated with early, severe, sensory deafness, arthritis, uveitis, and loss of balance. Examination of the cerebrospinal fluid may show an elevated white cell count with a predominance of either polymorphs or lymphocytes. Misinterpretation of the microbiological findings by inexperienced staff members may lead to a failure to correctly diagnose this disease. This is the first report of a series of cases of Strept. suis meningitis outside western Europe. Health authorities are urged to be aware of this disease in pork-consuming countries.
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PMID:Streptococcus suis meningitis. An important underdiagnosed disease in Hong Kong. 683 58

Ca(2+) acts as a fundamental signal transduction element in inner ear, delivering information about sound, acceleration and gravity through a small number of mechanotransduction channels in the hair cell stereocilia and voltage activated Ca(2+) channels at the ribbon synapse, where it drives neurotransmission. The mechanotransduction process relies on the endocochlear potential, an electrical potential difference between endolymph and perilymph, the two fluids bathing respectively the apical and basolateral membrane of the cells in the organ of Corti. In mouse models, deafness and lack or reduction of the endocochlear potential correlate with ablation of connexin (Cx) 26 or 30. These Cxs form heteromeric channels assembled in a network of gap junction plaques connecting the supporting and epithelial cells of the organ of Corti presumably for K(+) recycle and transfer of key metabolites, for example, the Ca(2+) -mobilizing second messenger IP(3) . Ca(2+) signaling in these cells could play a crucial role in regulating Cx expression and function. Another district where Ca(2+) signaling alterations link to hearing loss is hair cell apex, where ablation or missense mutations of the PMCA2 Ca(2+) -pump of the stereocilia cause deafness and loss of balance. If less Ca(2+) is exported from the stereocilia, as in the PMCA2 mouse mutants, Ca(2+) concentration in endolymph is expected to fall causing an alteration of the mechanotransduction process. This may provide a clue as to why, in some cases, PMCA2 mutations potentiated the deafness phenotype induced by coexisting mutations of cadherin-23 (Usher syndrome type 1D), a single pass membrane Ca(2+) binding protein that is abundantly expressed in the stereocilia.
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PMID:Ca2+ homeostasis defects and hereditary hearing loss. 2169 97

Hair cells of the inner ear detect sound stimuli, inertial or gravitational forces by deflection of their apical stereocilia. A small number of stereociliary cation-selective mechanotransduction (MET) channels admit K⁺ and Ca²⁺ ions into the cytoplasm promoting hair cell membrane depolarization and, consequently, neurotransmitter release at the cell basolateral pole. Ca²⁺ influx into the stereocilia compartment is counteracted by the unusual w/a splicing variant of plasma-membrane calcium-pump isoform 2 (PMCA2) which, unlike other PMCA2 variants, increases only marginally its activity in response to a rapid variation of the cytoplasmic free Ca²⁺ concentration ([Ca²⁺]_c). Missense mutations of PMCA2w/a cause deafness and loss of balance in humans. Mouse models in which the pump is genetically ablated or mutated show hearing and balance impairment, which correlates with defects in homeostatic regulation of stereociliary [Ca²⁺]_c, decreased sensitivity of mechanotransduction channels to hair bundle displacement and progressive degeneration of the organ of Corti. These results highlight a critical role played by the PMCA2w/a pump in the control of hair cell function and survival, and provide mechanistic insight into the etiology of deafness and vestibular disorders.
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PMID:PMCA2 pump mutations and hereditary deafness. 2945 11

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