We originally showed that the protocadherin 15 gene (Pcdh15) is necessary for hearing and balance functions; mutations in Pcdh15 affect hair cell development in Ames waltzer (av) mice. Here we extend that study to understand better how Pcdh15 operates in a cell. The original report identified 33 exons in Pcdh15, with exon 1 being noncoding; additional exons of Pcdh15 have since been reported. The 33 exons of Pcdh15 described originally are embedded in 409 kb of mouse genomic sequence, while the corresponding exons of human PCDH15 are spread over 980 kb of genomic DNA; the exons in Pcdh15/PCDH15 range in size from 9 to approximately 2000 bp. The genomic organization of Pcdh15/PCDH15 bears similarity to that of cadherin 23, but differs significantly from other protocadherin genes, such as Pcdhalpha, beta, or gamma. A CpG island is located approximately 2900 bp upstream of the PCDH15 transcriptional start site. The Pcdh15/PCDH15 promoter lacks TATAA or CAAT sequences within 100 bases upstream of the transcription start site; deletion mapping showed that Pcdh15 harbors suppressor and enhancer elements. Preliminary searches for alternatively spliced transcripts of Pcdh15 identified novel splice variants not reported previously. Results from our study show that both mouse and human protocadherin 15 genes have complex genomic structures and transcription control mechanisms.

Objectives/Hypothesis To evaluate the efficacy of photodynamic therapy (PDT) with the phthalocyanine photosensitizer Pc 4 for treating an animal model of recurrent respiratory papillomatosis (RRP). Methods Rabbit skin was grafted onto the dorsum of severe combined immunodeficient mice, two xenografts per animal. After the graft healed, it was inoculated with cottontail rabbit papillomavirus (CRPV). When papillomas developed, Pc 4 (0.6 or 1.0 mg/kg) was administered systemically, and 48 hours later, one papilloma of the two on each animal was exposed to 675-nm photoactivating light at either 100 or 150 J/cm2. In addition to the contralateral tumors, which received Pc 4 but no light, other controls included animals receiving light only or neither agent. Response was assessed by measuring papilloma size with a caliper. Some papillomas and residual skin were harvested for histological assessment. Results For the lower-dose PDT regimens, papilloma growth rates were not significantly different from the controls. In contrast, 13 of 15 papillomas receiving the higher Pc 4 dose (1.0 mg/kg) and the higher light fluence (150 J/cm2) regressed completely and did not regrow within the observation period of up to 79 days. The response of these papillomas was significantly different from the controls (P < .001). Histological analysis confirmed the absence of residual tumor following complete response and replacement with near-normal epithelium. Conclusions Pc 4-PDT is highly effective in treating virally induced (CRPV) papillomas in a murine model of RRP, and thus warrants further study as a treatment for HPV-induced papillomas.

Hypothesis Spiral ganglion neurons (SGN) in the Phex Hyp-Duk male mouse, a murine model of postnatal endolymphatic hydrops (ELH) undergo progressive deterioration reminiscent of human and other animal models of ELH with features suggesting apoptosis as an important mechanism. Background Histological analysis of the mutant's cochlea demonstrates ELH by postnatal day (P) 21 and SGN loss by P90. The SGN loss appears to occur in a consistent topographic pattern beginning at the cochlear apex. Methods SGN were counted at P60, P90 and P120. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative PCR, and immunohistochemical analyses of activated caspases-3, -8 and -9 were performed on cochlear sections obtained from mutants and controls. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling assay (TUNEL) was carried out on two mutants and two controls. Results Corrected SGN counts in control mice were greater in the apical turn of the cochleae at P90 and P120, respectively (P<0.01). Increased expression of activated caspase-3,-8 and -9 was seen in the mutant. At later time-points, activated caspase expression gradually declined in the apical turns and increased in basal turns of the cochlea. Quantitative and semi-quantitative PCR analysis confirmed increased expression of caspase-3, -8 and -9 at P21 and P40. TUNEL staining demonstrated apoptosis at P90 in the apical and basal turns of the mutant cochleae. Conclusion SGN degeneration in the Phex Hyp-Duk/Y mouse appear to mimic patterns observed in other animals with ELH. Apoptosis plays an important role in the degeneration of the SGN in the Phex Hyp-Duk male mouse.

To evaluate the accuracy and efficacy of fine-needle aspiration cytology (FNAC) in diagnosing thyroid nodules, correlating it with the histopathological findings. Methods: A retrospective evaluation of 314 patients was undertaken at a tertiary referral center of King Abdullah Medical City (KAMC), Makkah, Kingdom of Saudi Arabia, between 2010-2019. Patients who presented with thyroid swellings underwent ultrasonography and FNAC. If indicated, surgery was performed. The FNAC findings were compared to the final histopathological reports. Results: The findings for FNAC from our data set of 314 patients showed a sensitivity value of 79.8%, Original Article specificity of 82.1%, accuracy of 74.8%, positive predictive value of 74.8%, and negative predictive value of 85.9%. Conclusion: Our study showed that FNAC has high sensitivity and specificity in the initial evaluation of patients with thyroid nodules. When guided by ultrasonography, the accuracy can be markedly improved. Molecular markers once widely available can improve the diagnostic power of FNAC to be no less than the histopathologic evaluation of thyroid tissue.