Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Suppression of the 2f1-f2 distortion product otoacoustic emission (DPOAE) provides an effective paradigm for the study of functional cochlear maturation in humans. DPOAE iso-suppression tuning curves (STCs) represent some aspect of peripheral filtering, probably related to the boundaries of distortion generation. Studies conducted thus far suggest that the cochlear tuning assessed by this technique is adult-like in humans by term birth (Abdala et al., Hear. Res. 98 (1996) 38-53; Abdala and Sininger, Ear Hear. 17 (1996) 374-385). However, there have been no studies of cochlear tuning in premature human neonates. DPOAE STCs and suppression growth functions were measured from 14 normal-hearing adults, 33 term and 85 premature neonates to investigate the developmental time course of cochlear frequency resolution and non-linearity. Premature neonates showed non-adult-like DPOAE suppression at f2 of 1500 and 6000 Hz: (1) STCs were narrower in width (Q10) and steeper in slope on the low-frequency flank of the tuning curve; (2) suppressor tones lower in frequency than f2 produced atypically shallow growth of DPOAE suppression. The influence of immature conductive pathways cannot be entirely ruled out as a factor contributing to these results. However, findings may indicate that an immaturity exists in cochlear frequency resolution and non-linearity just prior to term birth. The bases of this immaturity are hypothesized to be outer hair cell in origin.
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PMID:A developmental study of distortion product otoacoustic emission (2f1-f2) suppression in humans. 968 15

MicroRNA-protein complexes (microRNPs) can activate translation of target reporters and specific mRNAs in quiescent (i.e., G0) mammalian cell lines. Induced quiescent cells, like folliculated immature oocytes, have high levels of cAMP that activate protein kinase AII (PKAII) to maintain G0 and immature states. We report microRNA-mediated up-regulated expression of reporters in immature Xenopus laevis oocytes, dependent on Xenopus AGO or human AGO2 and on FXR1, as in mammalian cells. Importantly, we find that maintenance of cAMP levels and downstream PKAII signaling are required for microRNA-mediated up-regulated expression in oocytes. We identify an important, endogenous cell state regulator, Myt1 kinase, as a natural target of microRNA-mediated up-regulation in response to xlmiR16, ensuring maintenance of oocyte immaturity. Our data reveal the physiological relevance of cAMP/PKAII-controlled posttranscriptional gene expression activation by microRNAs in maintenance of the immature oocyte state.
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PMID:Posttranscriptional activation of gene expression in Xenopus laevis oocytes by microRNA-protein complexes (microRNPs). 2153 68