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K Mou

Publications and source records attributed to K Mou.

7 recordsLinked to original sources
PubMed1998

Time-dependence and cell-type specificity of synergistic neurotrophin actions on spiral ganglion neurons.

The neurotrophins brain-derived neurotrophin (BDNF) and neurotrophin-3 (NT-3) synergistically enhance survival of spiral ganglion neurons such that simultaneous exposure to both compounds produces a larger response than would be expected from their individual effects. To elucidate the functional role of this neurotrophin interaction, we examined its temporal and cell-type specificity in vitro for both mouse and gerbil spiral ganglion neurons. Synergistic effects were transient; they were maximal within the first two postnatal days and declined during the first postnatal week. Both neurotrophins were, however, still efficacious at increasing cell survival. After postnatal day 10, the effects of coexposure to BDNF and NT-3 were additive rather than synergistic. Synergism declined more rapidly in mouse than gerbil neurons, reflecting the difference in cochlear development for each species. Only neurons without peripherin epitopes, putative type I neurons, showed synergistic survival effects; survival of peripherin-expressing neurons was purely additive. Therefore, during a restricted time period, identical neurotrophin stimuli are capable of preferentially enhancing survival of one class of neurons that compose approximately 95% of the adult spiral ganglion.

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PubMed1997

Synergistic effects of BDNF and NT-3 on postnatal spiral ganglion neurons.

Neurotrophins have profound effects on the development and maintenance of neurons that compose the VIIIth cranial nerve. In the auditory division of the nerve, brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) have been localized to the sensory epithelium, and their respective high-affinity tyrosine kinase receptors (TrkB and TrkC) are expressed within the neuronal population. By using a culture methodology that allows evaluation of single neurons, we determined that BDNF and neurotrophin-4 (NT-4), which both bind to the TrkB high-affinity receptor, greatly enhanced neuron survival above control cultures. NT-3, which acts via the TrkC high-affinity receptor, also increased survival, but to a lesser extent. By testing a variety of neurotrophin concentrations and combinations, we observed that simultaneous activation of the TrkB and TrkC receptors synergistically promoted neuron survival compared to cultures that contained either neurotrophin alone at the same total concentration. Antibody labeling showed that the high-affinity Trk receptors were localized predominantly to the neurons and not to the surrounding satellite cells; furthermore, TrkB- and TrkC-specific antibodies each labeled 100% of the cultured neurons. These results suggest that synergistic interactions between BDNF and NT-3 may be crucial for spiral ganglion neuron survival during the final stages of development.

Animals↗
PubMed1997

Stria vascularis morphogenesis in vitro.

Explants of neonatal murine stria vascularis were maintained in vitro to evaluate the process of morphogenesis in cochlear tissue. Immunohistochemical and electron microscopic studies showed that the relatively undifferentiated cells in culture attained morphological features characteristic of the stria vascularis cell types in vivo (marginal, intermediate and basal cells). The three kinds of cells formed a trilaminated tissue, with the epithelial cells bordering the culture medium, basal-like cells resting on the culture substrate, and the melanocytes layered between. Furthermore, approximately 20% of these cultures displayed a unique alignment of melanocytes which formed elongated bands along the contour of the tissue edge. However, only limited cell extensions were formed between different cell types and interdigitation amongst these processes was abbreviated. Thus, cells from different embryological origins divided, migrated and reestablished appropriate cell-to-cell associations to form a layered tissue similar to the stria vascularis in vivo.

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PubMed1996

[Genetic diagnosis of pelvic lymph node metastasis in prostate cancer using aspiration biopsy samples].

We have developed a highly sensitive method to detect pelvic lymph node(LN) metastasis using reverse transcriptase-polymerase chain reaction(RT-PCR) with the primers specific for prostate-specific antigen(PSA) gene in combination with the fine needle aspiration biopsy(FNAB). The specimens were obtained from pelvic LN from 15 prostate cancer patients and 15 bladder cancer patients. The aspirated samples (0.05 approximately 0.1 ml) were used for detecting the fragment of PSA mRNA by RT-PCR and Southern blot analysis, and the rest of samples were submitted to conventional cytology. Expression of PSA gene was detected in 9 cases of FNAB samples including all 5 cytologically positive and further more 2 cytologically class III cases, and 2 of 8 cytologically negative cases. RT-PCR of FNAB samples from all cases of bladder cancer were negative for the detection of PSA gene. The sensitivity of PSA gene by RT-PCR was very high and could detect 10 degrees cancer cell. In conclusion, our study suggested that RT-PCR for detection of PSA gene in FNAB samples might become a new diagnostic tool for detection of small foci of prostatic cancer metastasis in LN and combination use of RT-PCR and cytology could greatly contribute to accuracy in diagnosis.

Aged↗
PubMed1995

Osteopontin expression detected in adult cochleae and inner ear fluids.

Localization of protein epitopes and mRNA expression showed that there was a wide-spread distribution of osteopontin (OPN) within the membranous labyrinth of the adult mammalian cochleae. Immunoreaction product and mRNA were found within the stria vascularis, VIIIth cranial nerve, spiral ligament and limbus. Only specific cell types within these regions contained abundant OPN mRNA or protein, the main cell type being fibrocytes that populate the spiral limbus and spiral ligament. Epithelial cells that line the luminal surface of the stria vascularis (marginal cells) and neurons that compose the vestibular and auditory ganglia also showed high opn expression. The pattern of anti-OPN staining within membranous labyrinth was comparable to that observed in tissues such as gall bladder, breast and kidney. In those tissues, luminal epithelial cells, corresponding to the marginal cells of the stria vascularis, may be responsible for manufacturing and secreting OPN into the luminal fluids. consistent with those observations, we detected OPN epitopes in cochlear fluids withdrawn from the scalae media and tympani of the cochlea. We found that the protein species in cochlear fluid differed from those present in cerebrospinal fluid (CSF) suggesting that OPN exists in tissue-specific isoforms that may correspond to particular cellular functions.

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