Ceramide-1-phosphate protection of cochlear hair cells against cisplatin ototoxicity

BACKGROUND

Ceramide-1-phosphate (C1P) is a phosphorylated form of ceramide. While ceramide is known to be an inducer of apoptosis of cochlear hair cells in cisplatin ototoxicity, little is known about the function of C1P in cochlear diseases.

PURPOSE

The present study was designed to examine whether C1P could protect cochlear hair cells against cisplatin ototoxicity.

MATERIALS AND METHODS

Explants of cochlear basal turns collected from C57BL/6J mice at postnatal days 3-5 were used in all experiments. Cochlear explants were exposed to 5 or 10 μM cisplatin for 48 h to assess the effects of C1P, NVP-231 (a ceramide kinase inhibitor), or ceramide. Western blotting of pAkt/Akt and pMAPK/MAPK was examined to check whether this pathway was modulated by C1P.

RESULTS

C1P activated the Akt and MAPK pathway and significantly reduced cochlear cell death induced by cisplatin. Coadministration of cisplatin and ceramide significantly increased cochlear hair cell death. In addition, when treating cochlear hair cells with NVP-231 in the presence of cisplatin or ceramide, a remarkable increase in apoptosis of hair cells was observed.

CONCLUSION

The present findings confirmed the protective effects of C1P in the cisplatin ototoxicity. The balance between ceramide and C1P may play a critical role in the determination of hair cell fate in cisplatin ototoxicity.

In vivo confocal microscopy of early corneal epithelial recovery in patients with chemical injury

PURPOSE

To investigate the early recovery of corneal epithelium in patients with chemical injuries by the application of in vivo laser scanning confocal microscopy (LSCM).

METHODS

LSCM was performed on 26 eyes of 18 consecutive patients at 1, 2, and 3 months post injury. The morphology of central corneal epithelium and limbus was evaluated. Analysis was performed to compare the densities of corneal apical surface cells (ASCs) and basal epithelial cells (BECs) among different injury severity and time points after injury. The comparisons were also made on inflammatory cells (ICs) and dendritic cells (DCs) infiltrating at the limbus. Moreover, the presence rate of palisades of Vogt (POV) was analyzed at 3 months post injury.

RESULTS

Corneal re-epithelialization was found within 3 months post injury in all eyes, except that persistent epithelium defect was identified in grade IV injured eyes even at 3 months after injury. The injury severity had a significantly negative correlation with the densities of ASCs. However, it had no relationship with the densities of BECs. The density of ICs at the limbus decreased significantly with the prolongation of follow-up, except in the grade I injured eyes. The presence rate of POV also had a significantly negative correlation with injury severity.

CONCLUSION

Epithelial recovery after chemical injury varied in cellular morphology and the densities of ASCs among eyes with different injury severity. The presence rates of POV decreased with the aggravation of injury. LSCM is a feasible method for observing the early recovery of corneal epithelium in patients with chemical injuries.

Prevalence and factors associated with neck and jaw muscle modulation of tinnitus

Forceful contractions of neck and jaw muscles have consistently been shown to modulate tinnitus and can be used to screen patients who are responsive to somatic stimulation and, therefore, optimal candidates for somatosensory-based treatment. To identify the factors associated with somatic modulation of tinnitus, 163 patients underwent 19 neck and jaw maneuvers after an extensive physiological and audiological profile was compiled. Overall, tinnitus was modulated in 57.1% of ears tested. Unilateral tinnitus showed greater prevalence of modulation. Neck maneuvers generally decreased tinnitus loudness, whereas jaw maneuvers increased loudness. Female gender and buzzing tinnitus were associated with a high prevalence of modulation and a decrease in tinnitus loudness. Loud tinnitus and low-pitched tonal tinnitus were associated with exacerbation of the condition as a result of somatic testing. Use of these characteristics to select optimal candidates for somatosensory-based tinnitus therapies may be essential for the development of an effective approach for tinnitus treatment.

Does a history of postoperative ileus predispose to recurrent ileus after multistage ileal pouch-anal anastomosis?

BACKGROUND

Although postoperative ileus (POI) is a common complication after major abdominal colorectal surgery, it is unknown whether a history of POI predisposes to recurrent POI in subsequent surgeries. In the present retrospective case-control study, conducted at the colorectal surgery division of a tertiary care center, we attempted to identify factors that may predict recurrent POI in ulcerative colitis (UC) patients undergoing three-stage ileal pouch-anal anastomosis (IPAA).

METHODS

Charts of UC patients undergoing three-stage IPAA were reviewed. All patients received a standardized accelerated postoperative care pathway. Patients were assigned to one of 3 categories: Group A patients did not have POI after either initial subtotal colectomy (STC) or subsequent IPAA, Group B patients developed POI only after initial STC, and Group C patients developed POI after both STC and IPAA.

RESULTS

The study group consisted of 91 patients. There were 71 (78 %) patients in Group A, 14 (15 %) patients in Group B, and 6 (7 %) patients in group C. There was no significant difference in any demographic or clinical features among patients that developed no POI, those that developed POI only after STC, and those that developed POI after both STC and IPAA.

CONCLUSIONS

POI is difficult to predict after first- and second-stage IPAA. Clinical factors and a history of POI from first-stage IPAA do not predict POI after second-stage IPAA. Patients with a history of POI after STC do not have an increased risk of developing recurrent POI.