bluuebunny/crossref_metadata_2025 huggingface dataset:
Autoschizis of human ovarian carcinoma cells: Scanning electron and light microscopy of a new cell death induced by sodium ascorbate: Menadione treatment
Authors: Gilloteaux J. , Jamison J. M. , Arnold D. , Jarjoura D. , von Greuningen V. , Summers J. L.
Published: June 2010

Human ovarian carcinoma (MDAH 2774) cells were treated with sodium ascorbate (VC), menadione (VK3), or a combination of both in a ratio 100:1 for 1 h and then examined with scanning electron microscopy (SEM) and light microscopy (LM). Light microscopy data corroborated SEM observations, which demonstrated that death of VC + VK3‐treated tumor cells occurred primarily by autoschizis. This type of cell death is characterized by a decrease in cell size, cytoplasmic self‐excisions, and nuclear and nucleolar morphologic degradations without the formation of apoptotic bodies. Ultimately, cell death results from karyorrhexis and karyolysis. This study illustrates that plasma membrane damage (branching filopodia, blisters, blebs) results from VC treatment; cytoskeletal damage and self‐morsellation are caused by VC, VK3, and VC+VK3 treatments. The VC treatment results in a 23% decrease in cell diameter while VK3‐treated cells decrease cell diameter by 66%. After 1 h of VC+VK3 treatment, a heterogenous cell population is found. This population can be resolved into one population whose diameters are 23% smaller than those of sham‐treated cells, and a second population whose diameters are approximately twice those of sham‐treated cells. This second population is indicative of doublet formation in which the cells appear to be dividing (an early stage of autoschizic cell death). One half of the doublet contains the cell nucleus while the other half consists of cytoplasm and membrane only. The enucleate portion of this doublet will then be excised. When the types of cell death are enumerated following VC+VK3 treatment 43% of the cells die by autoschizis, 3% by apoptosis, and 1.9% by oncosis. These results confirm that autoschizis is the principal form of cell death that results from the in vitro treatment of human ovarian carcinoma cells with the vitamin combination.
Specimen Charging and Detection of Signal from Non‐conductors in a Cathode Lens‐Equipped Scanning Electron Microscope
Authors: Zobačová J. , Frank L.
Published: June 2010

This paper concerns the problems connected with the observation of a nonconductive specimen in a scanning electron microscope (SEM) when incident electrons create a surface charge and a corresponding electric field. The special configuration of the cathode lens enables one to control the landing energy of primary electrons via the specimen bias. In the cathode lens, the accelerating electric field at the surface of the specimen combines itself with that of the surface charge in influencing the trajectories of the signal electrons and hence the detected signal level and the possible recapturing of slow secondaries. Recaptured electrons reduce the ultimate positive surface potential, which arises when working below the higher critical energy of electron impact. Computer simulations of electron trajectories were performed for the typical cathode lens configuration and for a model specimen characterized by emission yields similar to those for glass. The simulations brought an extensive set of data about the trajectories of both secondary and backscattered electrons. Furthermore, the data were processed in order to assess the charge balance between the emitted and recaptured electrons as well as the collection efficiency of the detector. The results include values of the ultimate positive surface potential and the detected signal level, both in dependence on the initial energy of the electron impact and the size of the field of view. Finally, the method for the determination of critical energy is reevaluated. This is based on the measurement of the time dependence of the detected signal.
Quantification of Dental Microwear by Tandem Scanning Confocal Microscopy and Scale‐Sensitive Fractal Analyses
Authors: Ungar Peter S. , Brown Christopher A. , Bergstrom Torbjorn S. , Walker Alan
Published: June 2010

Dental microwear analysis is among the most commonly used approaches to reconstructing the diets of extinct animal species and past peoples. The usual procedure involves imaging tooth wear surfaces by scanning electron microscopy (SEM). Surfaces are characterized quantitatively by measurement of individual wear features (pits and scratches) on photomicrographs. Recent studies of living animals have shown associations between diets on one hand and patterns of dental microwear on the other. Furthermore, patterns on fossil teeth have been used to reconstruct diets in extinct forms. However, conventional methods for microwear analysis are limited. Scanning electron microscopy does not provide a true representation of these surfaces in three dimensions, and identification and measurement of individual features is time consuming, subjective, and subject to high interobserver error. This paper describes a new approach to the analysis of dental microwear using tandem scanning confocal microscopy and scale‐sensitive fractal analyses. The instrument used in this study provides three‐dimensional coordinates representing surfaces at a resolution equivalent to that employed by most SEM microwear studies. Fractal analyses offer objective, repeatable, quantitative characterization of surfaces. This approach eliminates major sources of error and increases power to resolve differences between species. Moreover, rapid surface characterization will allow examination of large samples to assess within species variation and to make finer distinctions between species.
Measurements of absolute X‐ray generation efficiency for selected K, L, and M‐lines
Authors: Prasad M. Satya , Joy D. C.
Published: June 2010

The absolute efficiency of generation of a selection of K, L, and M‐ x‐ray lines has been measured as a function of the incident electron beam energy. At an overvoltage U=2 this efficiency falls within the range 1E‐4 to 1E‐7, with K‐lines being highest and L‐Lines usually being the lowest. It is shown that for all three families of lines the efficiency has a functional variation which has the form A. (U‐1)n, as first suggested by Compton and Allison, where A and n are constants. Values of A and n for the K, L, and M shells are tabulated. The smoothly varying behavior of the efficiency makes it well suited for analytical use and spectrum simulation purposes.
Calibration and quantification of fast intracellular motion (FIM) in living cells using correlation analysis
Authors: Vesely Pavel , Mikš Antonín , Novík Jiří , Boyde Alan
Published: June 2010

Video rate confocal laser scanning microscopy at the highest spatial and temporal resolution of backscattered light (BSL) imaging allowed for regular observation of fast intracellular motion (FIM) first revealed in living neoplastic cells. However, the absence of an objective evaluation has hampered further study of the mechanisms and biological significance of FIM. Particularly, a quantification of apparent differences in velocities that would complement and improve the current demonstration of FIM by color coding using the combination of red‐green‐blue (RGB) images had been missing. Standard methods of tracking or pattern recognition could not be applied because of the fuzzy nature of images of FIM. A search for a suitable method led to correlation analysis. It was calibrated on Brownian motion and a known type of motion, such as cell marginal ruffling, compared with FIM. Results approved its explanatory potential. Therefore, several crucial incidences of FIM could be analyzed. Apart from an argument against viewing FIM as a manifestation of simple Brownian motion, the correlation analysis of FIM in the adjacent peripheries of a rat fibroblast and a K4 rat sarcoma cell confirmed the notion of higher and uneven distribution of velocity of FIM in a tumor cell so far shown in colorcoded images only. This result and other yet unpublished observations indicate that the velocity and topology of FIM can also contribute to a biological distinction between neoplastic and normal cells. Regular application of the correlation analysis should further expand the study of FIM for its mechanisms and predictive value. Such an approach should be thoroughly examined for a contribution to the knowledge of cancer cells.
A differentially pumped secondary electron detector for low‐vacuum scanning electron microscopy
Authors: Jacka M. , Zadrazil M. , Lopour F.
Published: June 2010

A new design of secondary electron (SE) detector is described for use in low‐vacuum scanning electron microscopes. Its distinguishing feature is a separate detector chamber, which can be maintained at a pressure independent of the pressure in the specimen chamber. The two chambers are separated by a perforated membrane or mesh across which an electric field is applied, making it relatively transparent to low‐energy electrons but considerably less so to the gas molecules. The benefits of this arrangement are discussed. The final means of detecting the electrons can be a conventional scintillator and photomultiplier arrangement or any of the methods using the ambient gas as an amplifying medium. Images obtained with the detector show good SE contrast and low backscattered electron contribution.
Confocal microscopic image sequence compression using vector quantization and three‐dimensional pyramid
Authors: Cockshott W. Paul , Tao Yegang , Ao Gang , Balch Peter , Briones Ana M. , Daly Craig
Published: June 2010

The three‐dimensional (3‐D) pyramid compressor project at the University of Glasgow has developed a compressor for images obtained from confocal laser scanning microscopy (CLSM) device. The proposed method using a combination of image pyramid coder and vector quantization techniques has good performance at compressing confocal volume image data. An experiment was conducted on several kinds of CLSM data using the presented compressor compared with other well‐known volume data compressors, such as MPEG‐1.1 The results showed that the 3‐D pyramid compressor gave a higher subjective and objective image quality of reconstructed images at the same compression ratio, and presented more acceptable results when applying image processing filters on reconstructed images.
Three‐dimensional architecture of ribosomal DNA within Barley Nucleoli Revealed with Electron Microscopy
Authors: Iwano Megumi , Che Fang‐Sik , Takayama Seiji , Isogai Akira , Fukui Kiichi
Published: June 2010

To elucidate the topological positioning of ribosomal RNA genes (rDNA) and nucleolar structure in three dimensions, we examined the localization of rDNA using in situ hybridization (ISH) analysis by scanning electron microscopy (SEM). The rDNA genes within the three‐dimensional architecture of nucleoli were detected on chromatin fibers that connect a thick strand‐like structure and a protrusion of rDNA into the inner nuclear hole where the nucleolus is formed. This novel use of ISH together with SEM is useful for the analysis of nucleolar structure in detail. Furthermore, rDNA was detected at the periphery of the fibrillar centers (FCs) of the nucleolus using immuno‐gold labeling together with transmission electron microscopy (TEM). In situ hybridization with TEM confirmed that rDNA is naked and thus active in the FCs of nucleoli; ISH with SEM confirmed that rDNA is not covered with ribonucleo proteins at the protruding point and is thus inactive. We also show that the distribution pattern of FCs differs from sample to sample. These results indicate that rDNA is transcribed dynamically in a time‐ and region‐specific manner over the course of the cell cycle.
Ultrastructure changes induced by dry film formation of a trisodium phosphate blend, antimicrobial solution
Authors: Lea P. , Ding S.‐F. , Lemez S. B.
Published: June 2010

Trisodium phosphate (TSP) has been reported to have antimicrobial activity and is approved by the U.S. Department of Agriculture for use in food processing applications. A novel (U.S. Patent 6,184,198), antimicrobial solution containing a blend of TSP, sodium bicarbonate, and sodium carbonate (TSP blend) has demonstrated effective inhibition of microbial contamination in a broad spectrum of applications. This high‐resolution cold field emission scanning electron microcopy (LVSEM) investigation details structural changes and dry film formation in various classes of microbes as a mechanism for antimicrobial activity of this solution. The results showed that this TSP blend solution completely inhibited the growth of pathogenic E. coli O157:H7, and Salmonella bacteria, the mold Cryptococcus, as well as a Norwalk virus surrogate‐feline calicivirus. Results by LVSEM confirmed that the antimicrobial effect was induced when encapsulating the target microbes in a high lubricity film that is formed around these organisms as the solution dries. The thickness of the film was estimated to be approximately 60 nm.
Measurement of total gas scattering cross‐section
Authors: He Jing , Joy David C.
Published: June 2010

Experimental measurements are presented of the total scattering cross‐section of four gases: He, Air, CH4, and Argon as a function of electron beam energy. The method used was that of Gauvin. A comparison of theoretical estimates of the total scattering cross‐section with the experimental data indicates that the model used gives generally reliable results. The data confirm that the gases tend to be molecular rather than atomic in nature in this pressure range (1–300 Pascal). The factors affecting the accuracy of these results are examined.
Brush‐like fibers on the human chromosome periphery
Authors: Wen Guang Y. , Fisher Mariel B. , Genovese Marilyn , Goldberg Erick M. , Jenkins Edmund C.
Published: June 2010

A brush‐like border apparently composed of fibers protruding from metaphase chromosomes of human lymphocytes was observed for the first time using transmission (TEM) and scanning electron microscopy (SEM). On the basis of size and sensitivity to colcemid, the fibers may be related to microtubules and spindle organization. The brush‐like fibers were observed when chemically fixed metaphase chromosome spreads were placed on glass slides and maintained under “wet” conditions (not allowed to air dry after fixation for conventional cytogenetic protocols) until postfixation protocols for TEM and SEM were performed. The purpose of this study was to establish the occurrence of the brush‐like fibers and to determine the effects of colcemid on these fibers.
Contrast at very low energies of the gold/carbon specimen for resolution testing
Authors: Müllerová Ilona , Frank Luděk
Published: June 2010

This paper concerns the problem of testing the image resolution in scanned electron micrographs, namely from the point of view of the image contrast for the standard gold/carbon test specimen within the full energy scale, down to eV units. Microscopes equipped with a cathode lens are considered and experimental results are presented for three devices differing in vacuum conditions and fields surrounding the specimen. At very low energies, the contrast is shown to either invert or disappear and this ambiguity is discussed and confronted with data simulated on the basis of measured electron yields from gold and carbon. It is concluded that the observations can be explained in terms of the surface cleanliness and strength of the surrounding fields.
A method for imaging single clay platelets by scanning electron microscopy
Authors: Rouse Jason H. , Ferguson Gregory S. , White Sara T.
Published: June 2010

A method for preparing and observing clay platelets for size and shape analysis using scanning electron microscopy (SEM) was developed. Samples of the clay platelets were prepared by polyelectrolyte‐assisted adsorption onto a pyrolytic graphite surface. The use of graphite as a substrate was advantageous because of the low number of secondary electrons emitted from it during imaging by SEM. The resulting low background noise allowed the emission from the ∼1 nm thick clay sheets to be clearly visualized. Images of centrifuged montmorillonite showed large exfoliated platelets with lateral dimensions between 200 and 600 nm. In contrast, uncentrifuged montmorillonite appeared to contain a large amount of unexfoliated clusters. Although it was not possible to obtain high‐quality images of the smaller sheets of Laponite RD, the images of this material did contain size features comparable to the ∼30 nm2 size reported previously using light scattering, as well as transmission electron and atomic force microscopies.
Image signal‐to‐noise ratio estimation using the autoregressive model
Authors: Sim K. S. , Kamel Nidal S.
Published: June 2010

In the last two decades, a variety of techniques for signal‐to‐noise ratio (SNR) estimation in scanning electron microscope (SEM) images have been proposed. However, these techniques can be divided into two groups: first, SNR estimators of good accuracy, but based on impractical assumptions; second, estimators based on realistic assumptions but of poor accuracy. In this paper we propose the implementation of autoregressive (AR)‐model interpolation as a solution to the problem. Unlike others, the proposed technique is based on a single SEM image and offers the required accuracy and robustness in estimating SNR values.
A balanced technique for preparation of specimens from pathogenicity studies for scanning electron microscopy
Authors: Stadtländer Christian T. K.‐H. , Kirchhoff Helga
Published: June 2010

This paper reports our experiences with preparing delicate biological specimens for scanning electron microscopy. Three different washing methods were evaluated: One method allowed the analysis of the location of the bacterium Mycoplasma mobile on piscine gill epithelium and the optimal evaluation of histopathologic changes caused by this microbe. These results were achieved when specimens were washed three times in a cacodylic acid buffer after completion of the in vitro infection experiment in gill explant cultures. We also found that of three different concentrations of glutaraldehyde, a fixation with a 1.5% solution was sufficient to achieve excellent structural preservation, even without using post fixation in osmium tetroxide. Furthermore, this study showed that the use of acetone‐carbon dioxide in the critical point drying procedure resulted in well‐preserved piscine gill epithelium and mycoplasmas. Finally, long‐term storage of tissue specimens in 0.1 M cacodylic acid buffer is possible if the buffer is changed on a monthly basis to avoid growth of unwanted microorganisms, such as fungi.
A novel technique for visualizing electron beam induced charging
Authors: Tang Xiaohu , Joy David C.
Published: June 2010

Charging is one of the most important problems encountered in scanning electron microscopy and as a result this phenomenon it has received a lot of both theoretical and experimental attention. Despite this, many questions remain about the nature and behavior of charging because of the limitations of the experimental techniques available to study it. For example, although it is now straightforward to determine in situ the surface potential of a sample that is charging during irradiation, it is difficult to measure the lateral extent of the charging, or its persistence once the incident beam is switched off. We describe here a simple technique which provides a rapid way of visualizing the temporal and spatial behavior of charging phenomena.
Scanning the pressure‐induced distortion of fingerprints
Authors: Mil'shtein S. , Doshi U.
Published: June 2010

Fingerprint recognition technology is an important part of criminal investigations it is the basis of some security systems and an important tool of government operations such as the Immigration and Naturalization Services, registration procedures in the Armed Forces, and so forth. After the tragic events of September 11, 2001, the importance of reliable fingerprint recognition technology became even more obvious. In the current study, pressure‐induced changes of distances between ridges of a fingerprint were measured. Using calibrated silicon pressure sensors we scanned the distribution of pressure across a finger pixel by pixel, and also generated maps of an average pressure distribution during fingerprinting. Emulating the fingerprinting procedure employed with widely used optical scanners, we found that on average the distance between ridges decreases by about 20% when a finger is positioned on a scanner. Controlled loading of a finger demonstrated that it is impossible to reproduce the same distribution of pressure across a given finger during repeated fingerprinting procedures.
Robust image signal‐to‐noise ratio estimation using mixed lagrange time delay estimation autoregressive model
Authors: Sim K. S. , Chuah H. T. , Cheng Zheng
Published: June 2010

A new technique based on the statistical autoregressive (AR) model has recently been developed as a solution to signal‐to‐noise (SNR) estimation in scanning electron microscope (SEM) images. In the present study, we propose to cascade the Lagrange time delay (LTD) estimator with the AR model. We call this technique the mixed Lagrange time delay estimation autoregressive (MLTDEAR) model. In a few test cases involving different images, this model is found to present an optimum solution for SNR estimation problems under different noise environments. In addition, it requires only a small filter order and has no noticeable estimation bias. The performance of the proposed estimator is compared with three existing methods: simple method, first‐order linear interpolator, and AR‐based estimator over several images. The efficiency of the MLTDEAR estimator, being more robust with noise, is significantly greater than that of the other three methods.
Use of backscattered electron detector arrays for forming backscattered electron images in the scanning electron microscope
Authors: Wells O. C. , Gignac L. M. , Murray C. E. , Frye A. , Bruley J.
Published: June 2010

The backscattered electron (BSE) signal in the scanning electron microscope (SEM) can be used in two different ways. The first is to give a BSE image from an area that is defined by the scanning of the electron beam (EB) over the surface of the specimen. The second is to use an array of small BSE detectors to give an electron backscattering pattern (EBSP) with crystallographic information from a single point. It is also possible to utilize the EBSP detector and computer‐control system to give an image from an area on the specimen‐for example, to show the orientations of the grains in a polycrystalline sample (“grain orientation imaging”). Some further possibilities based on some other ways for analyzing the output from an EBSP detector array, are described.
Correction of logistic regression relative risk estimates and confidence intervals for systematic within‐person measurement error
Authors: Rosner B. , Willett W. C. , Spiegelman D.
Published: June 2010

Errors in the measurement of exposure that are independent of disease status tend to bias relative risk estimates and other measures of effect in epidemiologic studies toward the null value. Two methods are provided to correct relative risk estimates obtained from logistic regression models for measurement errors in continuous exposures within cohort studies that may be due to either random (unbiased) within‐person variation or to systematic errors for individual subjects. These methods require a separate validation study to estimate the regression coefficient λ relating the surrogate measure to true exposure. In the linear approximation method, the true logistic regression coefficient β* is estimated by bT/λ, where β is the observed logistic regression coefficient based on the surrogate measure. In the likelihood approximation method, a second‐order Taylor series expansion is used to approximate the logistic function, enabling closed‐form likelihood estimation of β*. Confidence intervals for the corrected relative risks are provided that include a component representing error in the estimation of λ. Based on simulation studies, both methods perform well for true odds ratios up to 3·0; for higher odds ratios the likelihood approximation method was superior with respect to both bias and coverage probability. An example is provided based on data from a prospective study of dietary fat intake and risk of breast cancer and a validation study of the questionnaire used to asses dietary fat intake.
Skill and uncertainty in climate models
Authors: Hargreaves Julia C.
Published: June 2010

Analyses of skill are widely used for assessing weather predictions, but the time scale and lack of validation data mean that it is not generally possible to investigate the predictive skill of today's climate models on the multidecadal time scale. The predictions made with early climate models can, however, be analyzed, and here we show that one such forecast did have skill. It seems reasonable to expect that predictions based on today's more advanced models will be at least as skillful. In general, assessments of predictions based on today's climate models should use Bayesian methods, in which the inevitable subjective decisions are made explicit. For the AR4, the Intergovernmental Panel on Climate Change (IPCC) recommended the Bayesian paradigm for making estimates of uncertainty and probabilistic statements, and here we analyze the way in which uncertainty was actually addressed in the report. Analysis of the ensemble of general circulation models (GCMs) used in the last IPCC report suggests there is little evidence to support the popular notion that the multimodel ensemble is underdispersive, which would imply that the spread of the ensemble may be a reasonable starting point for estimating uncertainty. It is important that the field of uncertainty estimation is developed in order that the best use is made of current scientific knowledge in making predictions of future climate. At the same time, it is only by better understanding the processes and inclusion of these processes in the models, the best estimates of future climate will be closer to the truth. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Climate Models and Modeling > Knowledge Generation with Models
Present and future of antisense therapy for splicing modulation in inherited metabolic disease
Authors: Pérez Belen , Rodríguez‐Pascau Laura , Vilageliu Luisa , Grinberg Daniel , Ugarte Magdalena , Desviat Lourdes R.
Published: June 2010

The number of mutations identified deep in introns which activate or create novel splice sites resulting in pathogenic pseudoexon inclusion in mRNA continues to grow for inherited metabolic disease (IMD) and other human genetic diseases. A common characteristic is that the native splice sites remain intact thus retaining the potential for normal splicing. Antisense oligonucleotides (AO) have been shown to modulate the splicing pattern by steric hindrance of the recognition and binding of the splicing apparatus to the selected sequences. In the case of pseudoexons, AO force the use of the natural splice sites, recovering normally spliced transcripts encoding functional protein. This review summarizes the present knowledge of antisense splicing modulation as a molecular therapy approach for pseudoexon‐activating mutations, with a focus in IMD. Although the feasibility of treatment for patients with IMD has yet to be proven, it appears to be clinically promising, as positive results have been reported in cellular and animal models of disease, and antisense therapy for splicing modulation is currently in the clinical trials phase for Duchenne muscular dystrophy patients. Here, we review the most recent advances in AO stability, targeting and delivery, and other issues to be considered for an effective treatment in the clinical setting. Although the number of patients who can be potentially treated is low for each IMD, it represents an excellent therapeutical option as a type of personalized molecular medicine which is especially relevant for diseases for which there is, to date, no efficient treatment.
Preparation of Diacid 1,3‐Diacylglycerols
Authors: Craven R. John , Lencki Robert W.
Published: June 2010

A complete methodology (including synthesis, purification and analysis) for the preparation of 1,3‐DAG is described. For a successful synthesis project, the strengths and weaknesses of each particular process should be taken into account and measures taken to offset or balance potential weaknesses. To this end, we describe some of the challenges associated with: chemically and enzymatically catalyzed acylglycerol syntheses; recrystallization and flash chromatography for purification of partial acylglycerols; and thin‐layer chromatography (TLC) separation of DAG. For this work, 1‐MAG intermediates and subsequent diacid 1,3‐DAG were prepared using non‐enzymatic methods, whereas, monoacid 1,3‐DAG were prepared by enzymatic methods. It was not always possible to obtain pure samples of target compounds—in recrystallizations this is due to solid solution formation and co‐crystallization and in chromatographic separations it is due to co‐elution of components with similar Rf. Furthermore, TLC Rf of DAG is determined by two main factors: acyl chain length and positional isomerism. Interestingly, while the role of positional isomerism is well‐known, the role of acyl chain length in these separations has only recently come to light.
Reproducibility of Peripheral Quantitative Computed Tomography Measurements at the Radius and Tibia in Healthy Pre- and Postmenopausal Women
Authors: Szabo Kristina A. , Webber Colin E. , Gordon Christopher , Adachi Jonathan D. , Tozer Richard , Papaioannou Alexandra
Published: June 2010

Purpose

The objectives of this study were to utilise the XCT-2000 pQCT scanner to determine the mean values and the reproducibility of in vivo total, trabecular, and cortical volumetric bone measurements at distal and diaphyseal sites of the radius and the tibia, as well as calf muscle and subcutaneous fat areas, in healthy pre- and postmenopausal women.

Methods

Twenty-nine women (14 premenopausal and 15 postmenopausal) were recruited to participate in this study. Distal and diaphyseal sites of the radius (at 4% and 20% of the length of the radius) and tibia (at 4%, 38%, and 66% of the length of the tibia) were examined.

Results

The root mean square coefficient of variation for measurements at the distal tibia gave the most favorable reproducibility values for total (1.5%) and trabecular (1.6%) density, whereas the diaphyseal tibia showed the most favorable reproducibility value for cortical density (0.3%). The root mean square coefficients of variation for measurements of muscle and fat cross-sectional areas at the calf were 0.6% and 0.7%, respectively. At the distal tibia, the mean values for total ( P < .05) and trabecular ( P < .01) density were significantly lower in postmenopausal women than in premenopausal women.

Conclusions

The data presented here indicate that XCT-2000 pQCT scans at the tibia provide highly reproducible measurements of total, cortical, and trabecular bone as well as muscle and fat cross-sectional areas. Furthermore, significant differences in volumetric bone measurements between healthy pre- and postmenopausal women were evident only at the distal tibia, suggesting that this site warrants further study.
A newly identified Pirh2 substrate SCYL1‐BP1 can bind to MDM2 and accelerate MDM2 self‐ubiquitination
Authors: Yan Jing , Zhang Di , Di Yujun , Shi Huili , Rao Hai , Huo Keke
Published: June 2010

MINT‐7904857, MINT‐7904899: SCYL1‐BP1 (uniprotkb:Q5T7V8) physically interacts (MI:0915) with MDM2 (uniprotkb:Q00987) by anti bait coimmunoprecipitation (MI:0006)
Novel approaches to global mining of aberrantly methylated promoter sites in squamous head and neck cancer
Authors: Worsham Maria J. , Chen Kang Mei , Stephen Josena K. , Havard Shaleta , Benninger Michael S.
Published: June 2010

Objective

Promoter hypermethylation is emerging as a promising molecular strategy for early detection of cancer. We examined promoter methylation status of 1143 cancer‐associated genes to perform a global but unbiased inspection of methylated regions in head and neck squamous cell carcinoma (HNSCC).

Study Design

Laboratory‐based study.

Setting

Integrated health care system.

Subjects and Methods

Five samples, two frozen primary HNSCC biopsies and three HNSCC cell lines, were examined. Whole genomic DNA was interrogated using a combination of DNA immunoprecipitation (IP) and Affymetrix whole‐genome tiling arrays.

Results

Of the 1143 unique cancer genes on the array, 265 were recorded across five samples. Of the 265 genes, 55 were present in all five samples, and 36 were common to four of five samples, 46 to three of five, 56 to two of five, and 72 to one of five samples. Hypermethylated genes in the five samples were cross‐examined against those in PubMeth, a cancer methylation database combining text mining and expert annotation (http://www.pubmeth.org). Of the 441 genes in PubMeth, only 33 are referenced to HNSCC. We matched 34 genes in our samples to the 441 genes in the PubMeth database. Of the 34 genes, eight are reported in PubMeth as HNSCC associated.

Conclusion

This pilot study examined the contribution of global DNA hypermethylation to the pathogenesis of HNSCC. The whole‐genome methylation approach indicated 231 new genes with methylated promoter regions not yet reported in HNSCC. Examination of this comprehensive gene panel in a larger HNSCC cohort should advance selection of HNSCC‐specific candidate genes for further validation as biomarkers in HNSCC.
Survival in oral cavity minor salivary gland carcinoma
Authors: Kakarala Kiran , Bhattacharyya Neil
Published: June 2010

Objective

To describe the epidemiology and comparative survival for minor salivary gland cancer of the oral cavity.

Study Design

Historical cohort study.

Setting

Academic medical center.

Subjects and Methods

Cases of minor salivary gland cancer of the oral cavity were extracted from the Surveillance, Epidemiology, and End Results database (1988‐2005) and staged. Kaplan‐Meier survivals were compared according to histology as well as T stage and N stage. A Cox proportional hazards model incorporating histology, T stage, N stage, age, and sex was analyzed.

Results

A total of 639 salivary gland cancers of the oral cavity (55% female; mean age, 56 years) were identified with complete staging information, consisting of 318 mucoepidermoid, 169 adenoid cystic, 139 adenocarcinoma, and 14 acinic cell cancers. The hard palate and gums were the most common subsites involved (87.6%), followed by lip (7.2%) and tongue (5.2%). At presentation, T1 and T4 tumors predominated (42.6% and 35.2%, respectively); 93.4 percent were N0. Overall mean survival (months) was 157.9 and was similar across histologic subtypes: mucoepidermoid (172.4), adenoid cystic (141.4), acinic cell (138.7), and adenocarcinoma (147.2). Survival for low‐ and intermediate‐grade mucoepidermoid carcinoma (171.0 and 182.3, respectively) was better than survival for high‐grade mucoepidermoid carcinoma (50.3, P < 0.001). On multivariate analysis, N stage (P < 0.001) was the most powerful predictor of survival, along with T stage (P = 0.013), age (P < 0.001), and sex (P < 0.001).

Conclusion

T stage and N stage are the most powerful predictors of survival in minor salivary gland carcinoma of the oral cavity. With the exception of high‐grade mucoepidermoid carcinoma, survival for these lesions is generally favorable.
Cochlear implantations in young children with cochlear nerve deficiency diagnosed by MRI
Authors: Kang Woo Seok , Lee Jeong Hyun , Lee Ha Na , Lee Kwang‐Sun
Published: June 2010

Objective

To investigate postoperative outcomes after cochlear implantation in young children with cochlear nerve deficiency and compare the results with those of cochlear implantation in patients with normal cochlear nerve.

Study Design

Historical cohort study.

Setting

Tertiary referral center.

Subjects and Methods

Six children under the age of 36 months with cochlear nerve deficiency, as determined by magnetic resonance imaging (MRI), received cochlear implantation between July 2006 and March 2008. Fifteen children under the age of 36 months with normal cochlear nerve in the implanted ear underwent cochlear implantation during the same period and were selected as the control group. Medical records, imaging studies, and speech evaluations were reviewed.

Results

Our study group scored lower in the Infant‐Toddler Meaningful Auditory Integration Scale compared to the control group. Our study group produced categories of auditory performance scores not less than 4 except for one patient. Speech intelligibility rating scores in the control group gradually increased after cochlear implantation, but for the study group, the score remained zero 12 months after the implantation. In open‐set one‐syllable tests, five patients with cochlear nerve deficiency showed no response at the latest follow‐up, whereas patient 6 began to show delayed improvement after 18 months. The results of the open‐set two‐syllable test were similar to those of the open‐set one‐syllable test.

Conclusion

Young children with nonvisualized cochlear nerve on MRI showed worse outcomes compared to the children with normal cochlear nerve. Cochlear nerve deficiency on MRI is a marker of very poor outcome with cochlear implantations.
Fractal quantitative endoscopic evaluation of the upper airway in patients with obstructive sleep apnea syndrome
Authors: Delides Alexander , Viskos Alexandros
Published: June 2010

Objective

To analyze computer‐assisted quantitative measurements of endoscopic images taken during fiberoptic nasopharyngoscopy with Müller's maneuver that were processed with the use of fractal geometry and correlate them with the apnea‐hypopnea index of patients with obstructive sleep apnea syndrome as well as habitual snorers.

Study Design

Diagnostic test assessment for the analysis of images acquired through fiberoptic nasopharyngoscopy with Müller's maneuver and processed with the use of fractal geometry.

Setting

Sleep laboratory in a tertiary care private hospital in Athens, Greece.

Subjects and Methods

A total of 42 subjects (25 patients, 17 control subjects) underwent fiberoptic endoscopic nasopharyngoscopy with Müller's maneuver and polysomnographic overnight testing. Endoscopic images were digitally analyzed, and fractal analysis software was used to determine fractal dimensions of postpalatal airway contour during quiet inspiration and Müller's maneuver. Findings were correlated with the apnea‐hypopnea index.

Results

Fractal dimension of collapsed airway and airway collapsibility was shown to be correlated with the apnea‐hypopnea index (r = −0.481 and 0.518). We used 9.5 percent airway collapsibility on the basis of fractal dimensions as a cutoff (decided according to a receiver operating characteristic curve) and found that the predictability of obstructive sleep apnea had a sensitivity of 92.0 percent (95% confidence interval 75.03‐97.78) and a specificity of 82.4 percent (95% confidence interval 58.97‐93.8), with a positive predictive value of 88.5 percent and a negative predictive value of 87.5 percent (P < 0.0001).

Conclusion

Fractal analysis provides an additional measure of objectivity for the interpretation of computer‐assisted quantitative endoscopic evaluation of patients with obstructive sleep apnea. Nevertheless, as confidence intervals show, some uncertainty remains regarding the real population estimate, and therefore additional studies involving larger population groups are encouraged.
The diagnostic value of diffusion‐weighted magnetic resonance imaging in detecting a residual cholesteatoma
Authors: Aarts Mark C.J. , Rovers Maroeska M. , van der Veen Erwin L. , Schilder Anne G.M. , van der Heijden Geert J.M. , Grolman Wilko
Published: June 2010

In this evidence‐based case report, we address the following clinical question: What is the predictive value of diffusion‐weighted magnetic resonance imaging (DW MRI) for detecting a residual cholesteatoma in patients with chronic otitis media with cholesteatoma who have previously undergone a canal‐wall‐up procedure? We searched for relevant synonyms for the determinant, MRI, and for the outcome, cholesteatoma, and retrieved relevant publications in Embase, PubMed, Cinahl, and Web of Science by using search terms in the title and abstract fields. The search yielded 683 records, of which 11 were relevant and valid for our clinical question. We pooled the data of the MRI findings of the included studies by adding the two‐by‐two tables of the individual studies. For the eight echo planar imaging (EPI) DW MRI studies, this resulted in a pooled sensitivity, specificity, positive predictive value, and negative predictive value of 68 percent, 87 percent, 81 percent, and 78 percent, respectively. For the three non‐echo planar (non‐EPI) DW MRI studies, the sensitivity, specificity, positive predictive value, and negative predictive value were 97 percent, 97 percent, 97 percent, and 97 percent, respectively. DW MRI, especially the non‐EPI DW MRI, appears to be a rather accurate method, as opposed to a standard second‐look operation, for the follow‐up of patients who have undergone a canal‐wall‐up procedure for a chronic otitis media with cholesteatoma and who have no clinical signs of recurrent cholesteatoma.
Otolaryngology office‐based treatment of obstructive sleep apnea‐hypopnea syndrome with titratable and nontitratable thermoplastic mandibular advancement devices
Authors: Friedman Michael , Pulver Tanya , Wilson Meghan N. , Golbin Dina , Leesman Christopher , Lee George , Joseph Ninos J.
Published: June 2010

Objective

1) Share our experiences treating patients with obstructive sleep apnea‐hypopnea syndrome (OSAHS) with titratable and nontitratable thermoplastic mandibular advancement devices (MADs) fitted in our otolaryngology clinic. 2) Compare these devices in terms of objective response (OR), as defined by a ≥ 50 percent decrease in baseline apnea‐hypopnea index (AHI) and an AHI < 20, and subjective parameters, including adherence. 3) Determine overall success, as defined by OR plus adherence at two months follow‐up.

Study Design

Cohort study.

Setting

Tertiary care center.

Subjects and Methods

Patients with OSAHS who tried and failed or refused both continuous positive airway pressure (CPAP) and surgical therapy were fitted with a nontitratable Snore Guard (n = 38), nontitratable SomnoGuard 2.0 (n = 8), or titratable SomnoGuard AP (n = 41). Pre‐ and post‐treatment assessment included: 1) Epworth Sleepiness Scale, 2) snoring level, 3) polysomnogram. Patients were contacted at two months follow‐up to assess adherence and subjective parameters.

Results

OR was achieved in 62.1 percent of patients. Overall mean reduction in AHI was from 39.96 ± 23.70 to 14.86 ± 13.46 (P = 0.000). Adherence at two months was 58.5 percent. No significant differences were observed in OR or adherence according to MAD type, though improvements in AHI and minimum oxygen saturation were significantly better for the SomnoGuard AP than for the nontitratable devices. Overall success was 38.6 percent.

Conclusion

Thermoplastic MADs are a relatively inexpensive treatment alternative for patients with OSAHS who fail/refuse CPAP and upper airway surgery. They can be easily fitted in the otolaryngology clinic. Long‐term compliance, efficacy, and safety are unknown at this time.
Bipolar radiofrequency tonsillotomy compared with traditional cold dissection tonsillectomy in adults with recurrent tonsillitis
Authors: Nemati Shadman , Banan Rahmatollah , Kousha Abdorrahim
Published: June 2010

Objective

To compare short‐ and long‐term results of radiofrequency tonsillotomy and traditional cold dissection tonsillectomy in adult patients with recurrent tonsillitis.

Study Design

A randomized clinical trial.

Setting

A tertiary referral university hospital.

Subjects and Methods

Of 62 adults with recurrent tonsillitis, 24 patients were treated with cold dissection tonsillectomy, while radiofrequency tonsillotomy (RF) by use of radiofrequency induced thermotherapy probes was performed in the remaining 38 patients. Duration of surgery, amount of intraoperative bleeding, recovery time, postsurgical pain (measured by use of visual analogue scale on days 1, 3, 5, and 10 after surgery), dysphagia, weight loss, and time of return to normal diet and activity were measured. All the patients were followed for 12 to 24 months for recurrence of tonsillitis episodes.

Results

Comparing the radiofrequency tonsillotomy group to the cold dissection tonsillectomy group, mean duration of surgery was 16.89 versus 45.04 minutes, recovery time was 14.32 minutes versus 17.08 minutes, and amount of intraoperative bleeding was 15 to 20 cc versus 250 to 300 cc, respectively (P < 0.005). There was no difference between the two groups in the recurrence of tonsillitis episodes after 24 months.

Conclusion

Tonsillotomy with radiofrequency is a simple, rapid, and effective method in adult patients with recurrent tonsillitis.
Wrong‐site sinus surgery in otolaryngology
Authors: Shah Rahul K. , Nussenbaum Brian , Kienstra Matthew , Glenn Michael , Brereton Jean , Patel Milesh M. , Nielsen David , Roberson David W.
Published: June 2010

Objective

To determine the scope of wrong‐site sinus surgery.

Study Design

Electronic mail survey.

Setting

E‐mailed via the American Academy of Otolaryngology–Head and Neck Surgery's weekly newsletter.

Subjects and Methods

Members were asked about wrong‐site sinus surgery in an 11‐item survey.

Results

A total of 455 members responded (response rate 19.8%). Forty‐two (9.3%) have heard of a case of wrong‐site sinus surgery occurring. Twenty‐one cases were analyzed; of these, 10 (48%) implicated radiographic error, and the Universal Protocol was followed in one third. In seventeen reports (81%), there was disclosure to the family, one case with delayed disclosure; there was no disclosure in three cases. Sixty‐one percent (n = 266) are concerned about operating on the wrong sinus or side. Forty‐nine percent (n = 216) routinely use a checklist preoperatively. There is large variation in site marking for sinus surgery. Sixty‐five percent (n = 282) routinely review the computed tomography scan prior to surgery.

Conclusion

Approximately 10 percent of survey respondents know of a case of wrong‐site sinus surgery occurring; the majority of respondents are concerned about a wrong‐sinus or wrong‐sided surgery occurring in their practice. Otolaryngologists should be vigilant regarding the potential for inverted computed tomography images; there should be national efforts to address this latent systems defect. Surgeons should be trained in understanding the role of and engaging in disclosure and in other techniques that are of greatest support to the patient. Consideration of sinus‐specific checklists should be led by the societies representing sinus surgeons.
Legacies of the Tonsil Hospital
Authors: McCoul Edward D.
Published: June 2010

In response to a unique societal need, a dedicated tonsil hospital was established in New York City in 1921. Its contributions were both medical and moral. The hospital's director, Robert Fowler, impressed by the variability of available surgical techniques, undertook a quest for the “better tonsil operation.” His findings, published in an exhaustive text, highlighted several obscure anatomic relationships. Emphasis was on the primacy of anatomic mastery over the allure of new technology, with attention to the path leading from better surgery to better outcomes. Fowler's advocacy of both technical excellence and specialized patient care prefigured similar concerns held by otolaryngologists today.