[Cost analysis of GreenLight photoselective vaporization of the prostate versus standard transurethral resection of the prostate: Benefit of ambulatory care]. / Analyse des coûts de la photovaporisation prostatique au laser Greenlight versus résection transurétrale de la prostate : intérêt de la prise en charge ambulatoire.

PURPOSE: To compare the costs associated with GreenLight XPS 180W photoselective vaporization of the prostate (PVP) for an outpatient versus standard transurethral resection of the prostate (TURP) with a three nights hospitalization in a French private hospital. MATERIAL AND METHODS: A retrospective cost minimization analysis was performed between 2017 and 2019 in a French private hospital for the hospital stays associated with TURP and PVP procedures for benign prostatic hyperplasia (BPH). The peri-operative cost-benefit assessment of the two procedures was analyzed from the establishment's point of view according to the micro-costing method. RESULTS: 871 surgical treatment for BPH had been performed during the period of the study, including 743 photoselective laser vaporization (85%). The average length of stay of patients undergoing TURP was 3,7 days versus 0,9 days for PVP including 64,7% ambulatory. The cost-benefit was more of 500€ per patient in favor of ambulatory PVP compared with TURP in conventional three nights hospitalization for level 1 hospital stays. CONCLUSION: In this private hospital center, ambulatory PVP seemed more cost-effective than TURP with a three nights hospitalization for a severity level 1 patient. The financial profit for the establishment was mostly due to reduction of the main length of stay and ambulatory care. LEVEL OF EVIDENCE: 3.

Image restoration for confocal microscopy: improving the limits of deconvolution, with application to the visualization of the mammalian hearing organ.

Deconvolution algorithms have proven very effective in conventional (wide-field) fluorescence microscopy. Their application to confocal microscopy is hampered, in biological experiments, by the presence of important levels of noise in the images and by the lack of a precise knowledge of the point spread function (PSF) of the system. We investigate the application of wavelet-based processing tools to deal with these problems, in particular wavelet denoising methods, which turn out to be very effective in application to three-dimensional confocal images. When used in combination with more classical deconvolution algorithms, these methods provide a robust and efficient restoration scheme allowing one to deal with difficult imaging conditions. To make our approach applicable in practical situations, we measured the PSF of a Biorad-MRC1024 confocal microscope under a large set of imaging conditions, including in situ acquisitions. As a specific biological application, we present several examples of restorations of three-dimensional confocal images acquired inside an intact preparation of the hearing organ. We also provide a quantitative assessment of the gain in quality achieved by wavelet-aided restorations over classical deconvolution schemes, based on a set of numerical experiments that we performed with test images.

Spatio-temporal distribution of cellular retinoid binding protein gene transcripts in the developing and the adult cochlea. Morphological and functional consequences in CRABP- and CRBPI-null mutant mice.

The expression patterns of the mouse cellular retinoid binding protein genes were investigated by in situ hybridization analysis in the inner ear from 10.5 days post coïtum (dpc) up to the adult stage. The cellular retinoic acid binding protein II (CRABPII) and cellular retinol binding protein I (CRBPI) were present in a widespread and abundant pattern in cochlear structures during embryogenesis. Expression of the cellular retinoic acid binding protein I (CRABPI) is restricted during development in Kölliker's organ whilst cellular retinol binding protein II (CRBPII) is only visible after birth with a ubiquitous distribution in most regions of the cochlea including nervous components. No CRABP or CRBP transcripts were observed in the auditory receptors. Morphological observations of CRBPI- and CRABPI/CRABPII-null mutant fetus at 18.5 dpc do not show any structural modification at the level of the organ of Corti. Furthermore, electrophysiological tests performed by measuring distorsion-product otoacoustic emissions and auditory brainstem evoked responses did not present significant alteration of the auditory function for the different types of mutants. The expression of retinoid binding proteins in cochlear structures during embryogenesis could suggest important roles for these proteins during ontogenesis and morphogenesis of the inner ear. Despite these observations, morphological and functional data from mutant mice did not present obvious modifications of the cochlear structures and auditory thresholds. It is therefore unlikely that CRABPs and CRBPI are directly involved in development of the cochlea and hair cell differentiation.

Perilymphatic fluid compartments and intercellular spaces of the inner ear and the organ of Corti.

An in vitro preparation of the inner ear cochlea has been used to visualize the structural relationships of unfixed, living sensory cells and structural components within the intact hearing organ. By perfusing perilymphatic compartments of the cochlea with fluorochrome-conjugated dextran, the extracellular spaces were clearly outlined. The staining pattern illustrated the large fluid compartments formed by the tunnel of Corti, the space of Nuel, and the outer tunnel. The dextran solution also indicated the spaces between the outer hair cell rows, the inner hair cells, and the surrounding supporting cells. The staining pattern demonstrates that the organ of Corti has a loose structure, suggesting a weak mechanical coupling between the cells. Moreover, it is evident that substances applied to the perilymph (e.g., therapeutic drugs) will readily reach all the cells of the hearing organ. In addition to the intraorgan fluid compartments, the spiral limbus was shown to contain significant volumes of perilymph within the intercellular spaces forming the so-called teeth of Huschke between the interdental cells. An extensive system of bundles following the teeth of Huschke was shown to be completely immersed in perilymph. The bundles were stained by a potentiometric dye, which in the inner ear primarily stains nerve fibers and sensory cells, which may indicate a nervous control of cells in this region.

An in vitro preparation to access cellular and neuronal components in the mouse inner ear.

An in vitro mouse temporal bone preparation has been developed in order to allow the investigation of structures and functions in a living hearing organ. Fluorescent vital probes (a potentiometric styryl dye, RH 795, and a vital dye staining cellular cytoplasm, calcein) were perfused through the scala tympani to stain cellular components of the cochlea. Observations of the cochlear apical turn were performed using a confocal microscope. In spite of the anatomical constraints due to the small size of the mouse cochlea, detailed images were obtained. The sensory cells as well as their innervating nerve fibres were clearly seen. Nerve fibres crossing the tunnel of Corti and projecting to the outer hair cells could also be visualised.

CD1 hearing-impaired mice. I: Distortion product otoacoustic emission levels, cochlear function and morphology.

The levels of distortion product otoacoustic emissions (DPOAEs) were measured in a strain of hearing-impaired mutant mice (CD1) at various stages of outer hair cell impairment and compared to those of a control inbred strain (CBA/J). Parallel measurements of cochlear potentials and auditory brainstem evoked responses (ABRs) were performed and surface preparations of organs of Corti were observed using phalloidin staining of filamentous actin. Comparison of DPOAEs (elicited by stimulus levels of 60 and 70 dB SPL) with standard functional tests allowed the categorization of CD1 ears into two groups on the basis of the presence or absence of DPOAE, which corresponded to mean ABR thresholds greater or less than 40 dB nHL respectively. When adopting ABR threshold as the gold standard, this procedure yielded rates of false-positives and -negatives ranging from 5 to 16%. However, individual predictions of electrophysiological function from DPOAE levels were not accurate, owing to their large variance, and attempts to optimize stimulus levels did not reduce this variance. In contrast, the profiles of DPOAE level vs. f2 exhibited large correlations with ABR threshold profiles as a function of f2. It was also noteworthy that the mean levels of DPOAEs in CD1 mice recorded in frequency intervals with normal ABR thresholds were significantly smaller than those of CBA/J mice. Although hearing loss was revealed early both by DPOAEs and by other functional tests, surface preparations often remained normal until about 3-4 months of age.

CD1 hearing-impaired mice. II. Group latencies and optimal f2/f1 ratios of distortion product otoacoustic emissions, and scanning electron microscopy.

In our companion paper (Le Calvez et al., 1998), the levels of distortion product otoacoustic emissions (DPOAE) were collected in the ears of CD1 mice with progressive degeneration of cochlear outer hair cells (OHC). Their comparison to standard functional measurements such as auditory-evoked brainstem responses (ABR) showed that CD1 ears could be classified as normal or impaired in a frequency-specific manner using DPOAE levels. The present work reports how DPOAE phases and levels of young CD1 mice were affected by varying the frequency ratio of eliciting stimuli at frequencies f1 and f2. Normally hearing CBA/J mice served as controls. The rate of phase change of DPOAE when f1 was varied and f2 was fixed allowed the group delay of DPOAE to be derived. The changes of DPOAE levels during this procedure disclosed bandpass characteristics that several reports (Fahey and Allen, 1986; Brown and Gaskill, 1990) assumed to be the reflection of important features of cochlear micromechanics, possibly in relation to the coupling of OHCs to the tectorial membrane. Group delays became significantly shorter when ABR thresholds exceeded 40 dB elevation. The bandpass filter characteristics strikingly depended on auditory function so that the optimal ratio f2/f1 progressively shifted from 1.24 to 1.50 or more when hearing loss increased. A difference was also noted between CD1 ears whose ABR thresholds were not yet increased and control CBA/J (optimal ratio 1.20). Scanning electron microscopy disclosed a variety of often minor OHC lesions that were only roughly correlated with cochlear function. However, the presence of abnormalities in the reticular lamina associated with early changes of DPOAE fine structure as a function of f2/f1 supported the hypothesis of some involvement of micromechanical features in the bandpass filter characteristics of DPOAE. The sensitivity of their measurement in pathological situations is potentially interesting.

The spontaneous appearance of hair cell-like cells in the mammalian cochlea following aminoglycoside ototoxicity.

Young rats (in vivo) and cochleas from neonatal rats (in vitro) were treated with ototoxic antibiotics. Scanning electron microscope observations of the cicatricial epithelium of the former outer hair cell region revealed cells with a tuft of microvilli at their apical surface that could contain actin filaments, as observed by phalloidin staining. The apical organization of these hair cell-like cells was reminiscent of fetal hair cells topped with a bundle of microvilli. During both in vivo and in vitro observations, and despite the use of several growth factors in vitro, these hair cell-like cells did not differentiate into mature sensory cells. These hair cell-like cells might represent an attempt by the former sensory epithelium to regenerate.