Keratin particle-induced osteolysis: a mouse model of inflammatory bone remodeling related to cholesteatoma.
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We implanted keratin and poly(methyl methacrylate) (PMMA) particles to the surface of mouse calvariae to produce a quantitative, localized, inflammatory bone remodeling similar to that seen in cholesteatoma. Both types of particles resulted in increased osteoclast density compared with controls. Osteoclasts infiltrated from marrow and vascular spaces and were active at the periphery of these spaces leading to significant bone remodeling, as demonstrated by the incorporation of bone-labelling fluorophores. Osteoclasts were rarely found on the surface of the calvariae, and mineral apposition rate at the ventral surface was not altered in keratin-implanted animals compared with nonoperated controls. While not useful for the study of the root cause of cholesteatoma, this model will allow the study ofpathologic bone remodeling related to cholesteatoma in a genetically defined animal. (+info)
Cholesteatoma of the upper urinary tract.
(2/27)
We report the case of a 57-year old patient with complex cystic image in right kidney. Following radical nephrectomy, the pathological study established the diagnosis of renal cholesteatoma. We discuss the frequency, pathogenesis, clinical presentation, propedeutics, histological findings and proposes for intervention observed in the literature. (+info)
First isolation of Bacteroides thetaiotaomicron from a patient with a cholesteatoma and experiencing meningitis.
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A 45-year-old man with a cholesteatoma experienced purulent meningitis. Microbial analysis of cerebrospinal fluid yielded in pure culture a gram-negative bacillus. Phenotypic methods were suggestive of a Bacteroides distasonis or either a Bacteroides thetaiotaomicron or Bacteroides ovatus infection. The isolate was identified by 16S rRNA gene sequence analysis as B. thetaiotaomicron. This is the first case of B. thetaiotaomicron meningitis in pure culture. (+info)
Suppressive activity of vitamin D3 on matrix metalloproteinase production from cholesteatoma keratinocytes in vitro.
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There is much evidence that degradation of the extracellular matrix is essential for the development of cholesteatomas and that this is induced by activation of matrix metalloproteinases (MMPs). Vitamin D3 (VD3) has several well-recognised biological activities, including suppression of MMP production. The present study, therefore, was undertaken to examine whether VD3 could suppress MMP production from cholesteatoma keratinocytes in vitro. Keratinocytes (2.5 x 10(5) cells/mL) induced from cholesteatoma tissue specimens were cultured with various concentrations of VD3. After one hour, lipopolysaccharide was added to the cell cultures at 100 mug/mL. The culture supernatants were then collected and assayed for MMP-1 and MMP-3 by ELISA. We also used ELISA to measure the levels of both TIMP (tissue inhibitor of metalloproteinase)-1 and TIMP-2 in culture supernatants. Addition of VD3 into keratinocyte cultures caused the suppression of MMP and TIMP production, which was increased by LPS stimulation. This was dose-dependent. The present results showing the suppressive activity of VD3 on the production of MMPs, which are responsible for tissue remodeling, strongly suggest that VD3 would be a good candidate for an agent in the medical treatment of, or prophylaxis for, cholesteatomas. (+info)
Cholesteatoma of external auditory canal: a case report.
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The authors present a case of cholesteatoma of external auditory canal (CEAC) with extensive invasion of mastoid; ossicle chain and tympanic membrane remained intact. The only symptom was chronic otorrhea. Diagnosis was based on clinical elements and CT scan was used to measure pathology and program surgery. Treatment was modified radical mastoidectomy associated with meatoplasty. Due to the insidious character of CEAC and the proximity with important structures of the external auditory canal, it must be always considered in differential diagnosis for lesions of external auditory canal. This case report intended to review clinical and surgical aspects of treatment of CEAC and present our approach in a case with severe lesions. (+info)
Growth of cholesteatoma by implantation of epithelial tissue along the femoral bone of rats.
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Cholesteatoma is a well-known infection resembling a pearl. Its histological aspect is of an epidermal cyst formation characterized by epidermal-keratinized tissue in the middle ear and mastoid that can migrate and erode to adjacent structures. AIM: To verify epidermal cyst (cholesteatoma) growth through implantation of auricular skin of a mouse next to its femoral bone. STUDY DESIGN: Experimental. MATERIAL AND METHOD: Ten healthy rats between two and five months of age and of both sexes underwent implantation of auricular skin on the femoral bone during a three-month period. Paraffin-embedded sections were obtained from the sample and stained with hematoxylin and eosin for pathology investigation. RESULTS: Macroscopic view: round soft yellowish granulation tissue. Microscopic view: keratinizing stratified squamous epithelium cystic formation. The cyst presented innermost corneal layer, resulted from keratinized skin, followed by granulated and squamous layers, and outermost basal layer. CONCLUSIONS: Growth of epidermal cyst (cholesteatoma) may start from a transplanted epithelial tissue next to the femoral bone of rats. (+info)
Readout-segmented EPI for rapid high resolution diffusion imaging at 3 T.
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Readout mosaic segmentation has been suggested as an alternative approach to EPI for high resolution diffusion-weighted imaging (DWI). In the readout-segmented EPI (RS-EPI) scheme, segments of k-space are acquired along the readout direction. This reduces geometric distortions due to the decrease in readout time. In this work, further distortion reduction is achieved by combining RS-EPI with parallel imaging (PI). The performance of the PI-accelerated RS-EPI scheme is assessed in volunteers and patients at 3T with respect to both standard EPI and PI-accelerated EPI. Peripherally cardiac gated and non-gated RS-EPI images are acquired to assess whether motion due to brain pulsation significantly degrades the image quality. Due to the low off-resonance of PI-driven RS-EPI, we also investigate if the eddy currents induced by the diffusion gradients are low enough to use the Stejskal-Tanner diffusion preparation instead of the twice-refocused eddy-current compensated diffusion preparation to reduce TE. It is shown that non-gated phase corrected DWI performs equally as well as gated acquisitions. PI-driven DW RS-EPI images with substantially less distortion compared with single-shot EPI are shown in patients-allowing the delineation of structures in the lower parts of the brain. A twice-refocused diffusion preparation was found necessary to avoid blurring in the DWI data. This paper shows that the RS-EPI scheme may be an important alternative sampling strategy to EPI to achieve high resolution T2-weighted and diffusion-weighted images. (+info)
Congenital cholesteatoma extending into the internal auditory canal and cochlea: a case report.
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We report here on a case of congenital cholesteatoma that extended into the internal auditory meatus and cochlea. A 17-year-old boy underwent surgery for a very large cholesteatoma, which was discovered behind an intact tympanic membrane. Pure tone audiometry revealed an unresponsive ear. High resolution temporal bone computed tomography showed perilabyrinthine extension with its absence in the vestibular area, and destruction of the bony cochlea at the basal turn, the tegmen and the posterior cranial fossa. Magnetic resonance imaging revealed no intracranial extension. Surgical exploration of the middle ear and the mastoid cavity revealed that both the vestibule and the basal turn of the cochlea were filled with a noninfected cholesteatoma. The cholesteatoma extended into the internal auditory meatus through translabyrinthine destruction; it extended into the basal turn of the cochlea through the infralabyrinthine route. The bony segment of the facial nerve canal demonstrated near total dehiscence. The cholesteatoma was removed by the transotic approach. Congenital cholesteatoma is characterized by no specific history. Therefore, early detection of this malady can be challenging, but it is important to prevent such complications as were observed in this reported case. (+info)