Virgilijus Uloza

Assessment of potential effects of the electromagnetic fields of mobile phones on hearing

BackgroundMobile phones have become indispensable as communication tools; however, to date there is only a limited knowledge about interaction between electromagnetic fields (EMF) emitted by mobile phones and auditory function. The aim of the study was to assess potential changes in hearing function as a consequence of exposure to low-intensity EMFs produced by mobile phones at frequencies of 900 and 1800 MHz.MethodsThe within-subject study was performed on thirty volunteers (age 18–30 years) with normal hearing to assess possible acute effect of EMF. Participants attended two sessions: genuine and sham exposure of EMF. Hearing threshold levels (HTL) on pure tone audiometry (PTA) and transient evoked otoacoustic emissions (TEOAEs) were recorded before and immediately after 10 min of genuine and/or sham exposure of mobile phone EMF. The administration of genuine or sham exposure was double blind and counterbalanced in order.ResultsStatistical analysis revealed no significant differences in the mean HTLs of PTA and mean shifts of TEOAEs before and after genuine and/or sham mobile phone EMF 10 min exposure. The data collected showed that average TEOAE levels (averaged across a frequency range) changed less than 2.5 dB between pre- and post-, genuine and sham exposure. The greatest individual change was 10 dB, with a decrease in level from pre- to post- real exposure.ConclusionIt could be concluded that a 10-min close exposure of EMFs emitted from a mobile phone had no immediate after-effect on measurements of HTL of PTA and TEOAEs in young human subjects and no measurable hearing deterioration was detected in our study.

Long-distance communication between laryngeal carcinoma cells.

Tunneling nanotubes and epithelial bridges are recently discovered new forms of intercellular communication between remote cells allowing their electrical synchronization, transfer of second messengers and even membrane vesicles and organelles. In the present study, we demonstrate for the first time in primary cell cultures prepared from human laryngeal squamous cell carcinoma (LSCC) samples that these cells communicate with each other over long distances (up to 1 mm) through membranous tunneling tubes (TTs), which can be open-ended or contain functional gap junctions formed of connexin 43. We found two types of TTs, containing F-actin alone or F-actin and α-tubulin. In the LSCC cell culture, we identified 5 modes of TT formation and performed quantitative assessment of their electrical properties and permeability to fluorescent dyes of different molecular weight and charge. We show that TTs, containing F-actin and α-tubulin, transport mitochondria and accommodate small DAPI-positive vesicles suggesting possible transfer of genetic material through TTs. We confirmed this possibility by demonstrating that even TTs, containing gap junctions, were capable of transmitting double-stranded small interfering RNA. To support the idea that the phenomenon of TTs is not only typical of cell cultures, we have examined microsections of samples obtained from human LSCC tissues and identified intercellular structures similar to those found in the primary LSCC cell culture.

Towards a computer-aided diagnosis system for vocal cord diseases

OBJECTIVE The objective of this work is to investigate a possibility of creating a computer-aided decision support system for an automated analysis of vocal cord images aiming to categorize diseases of vocal cords. METHODOLOGY The problem is treated as a pattern recognition task. To obtain a concise and informative representation of a vocal cord image, colour, texture, and geometrical features are used. The representation is further analyzed by a pattern classifier categorizing the image into healthy, diffuse, and nodular classes. RESULTS The approach developed was tested on 785 vocal cord images collected at the Department of Otolaryngology, Kaunas University of Medicine, Lithuania. A correct classification rate of over 87% was obtained when categorizing a set of unseen images into the aforementioned three classes. CONCLUSION Bearing in mind the high similarity of the decision classes, the results obtained are rather encouraging and the developed tools could be very helpful for assuring objective analysis of the images of laryngeal diseases.

Advances in laryngeal imaging

Imaging and image analysis became an important issue in laryngeal diagnostics. Various techniques, such as videostroboscopy, videokymography, digital kymograpgy, or ultrasonography are available and are used in research and clinical practice. This paper reviews recent advances in imaging for laryngeal diagnostics.

Laryngeal examination is superior to endoscopy in the diagnosis of the laryngopharyngeal form of gastroesophageal reflux disease

Objective. The laryngopharyngeal form of gastroesophageal reflux disease (LF GERD) is a frequent manifestation of supraesophageal GERD. Diagnosis of LF GERD is difficult: most of the common diagnostic methods of GERD have insufficient accuracy in establishing LF GERD. The purpose of this study was to evaluate the role of endoscopic and laryngologic examination in the diagnosis of LF GERD and to create a laryngoscopic reflux index (LRI). Material and methods. A total of 108 LF GERD patients and 90 controls were investigated. The criteria for LF GERD were: complaints, reflux-laryngitis, and esophagitis (endoscopically or histologically proven). Lesions in four laryngeal regions were evaluated: arytenoids (A), intraarytenoid notch (IAN), vestibular folds (VF), and vocal cords (VC). Three types of mucosal lesions were evaluated on a points basis: alterations of the epithelium, erythema, and edema. Total LRI was calculated by summing-up the indices in the separate laryngeal areas. Results. The LRI mean value (11.48±3.78 points) of LF GERD patients was statistically significantly greater than that (1.64±1.93 points) of the controls. The most significant laryngoscopic changes of LF GERD were: mucosal lesions of IAN, mucosal lesions of VC, and edema of VC. A combination of these three findings reliably distinguishes the LF GERD patients from controls in 95.9% of cases. The mucosal lesions of IAN have the greatest importance in diagnosing LF GERD: the odds ratio to LF GERD – 21.32, p<0.001. Endoscopic esophagitis was established in 36 (33.3%) cases. The severity of esophagitis did not correlate with the severity of the laryngeal findings. Conclusions. Laryngoscopy is superior to endoscopy in diagnosing LF GERD. Endoscopy has limited value in the diagnosis of LF GERD. Establishing the LRI could be helpful in the differential diagnosis of the disease in the everyday clinical practice.

Multidimensional voice analysis of reflux laryngitis patients

The aim of the study was to analyze and quantify the voice characteristics of reflux laryngitis (RL) patients and to determine the most important voice tests and voice-quality parameters in the functional diagnostics of RL. The voices of 83 RL patients and 31 persons in the control group were evaluated. Vocal function was assessed using a multidimensional set of video laryngostroboscopic, perceptual, acoustic, aerodynamic and subjective measurements according to the protocol elaborated by the Committee on Phoniatrics of the European Laryngological Society. The mean values of the hoarseness visual analogue scale assessment and voice handicap index were significantly higher (P<0.05) in the group of RL patients as compared to the controls. Objective voice assessment revealed a significant increase in mean values of jitter, shimmer and normalized noise energy (NNE), along with a significant decrease in pitch range, maximum frequency, phonetogram area (S) and maximum phonation time (MPT) in RL patients, both in the male and female subgroups. According to the results of discriminant analysis, the NNE, MPT, S and intensity range were determined as an optimum set for functional diagnostics of RL. The derived function (equation) makes it possible to assign the person to the group of RL patients with an accuracy of 86.7%. The sensitivity and specificity of eight voice parameters were found to be higher than 50%. The results of the present study demonstrate a reduction of phonation capabilities and voice quality in RL patients. Multidimensional voice evaluation makes it possible to detect significant differences in mean values of perceptual, subjective and objective voice quality parameters between RL patients and controls groups. Therefore, multidimensional voice analysis is an important tool in the functional diagnostics of RL.

Multiple feature sets based categorization of laryngeal images

This paper is concerned with an automated analysis of laryngeal images aiming to categorize the images into three decision classes, namely healthy, nodular, and diffuse. The problem is treated as an image analysis and classification task. Aiming to obtain a comprehensive description of laryngeal images, multiple feature sets exploiting information on image colour, texture, geometry, image intensity gradient direction, and frequency content are extracted. A separate support vector machine (SVM) is used to categorize features of each type into the decision classes. The final image categorization is then obtained based on the decisions provided by a committee of support vector machines. Bearing in mind a high similarity of the decision classes, the correct classification rate of over 94% obtained when testing the system on 785 laryngeal images recorded at the Department of Otolaryngology, Kaunas University of Medicine is rather promising.

Global Genomic Diversity of Human Papillomavirus 11 Based on 433 Isolates and 78 Complete Genome Sequences

ABSTRACT Human papillomavirus type 6 (HPV6) is the major etiological agent of anogenital warts and laryngeal papillomas and has been included in both the quadrivalent and nonavalent prophylactic HPV vaccines. This study investigated the global genomic diversity of HPV6, using 724 isolates and 190 complete genomes from six continents, and the association of HPV6 genomic variants with geographical location, anatomical site of infection/disease, and gender. Initially, a 2,800-bp E5a-E5b-L1-LCR fragment was sequenced from 492/530 (92.8%) HPV6-positive samples collected for this study. Among them, 130 exhibited at least one single nucleotide polymorphism (SNP), indel, or amino acid change in the E5a-E5b-L1-LCR fragment and were sequenced in full. A global alignment and maximum likelihood tree of 190 complete HPV6 genomes (130 fully sequenced in this study and 60 obtained from sequence repositories) revealed two variant lineages, A and B, and five B sublineages: B1, B2, B3, B4, and B5. HPV6 (sub)lineage-specific SNPs and a 960-bp representative region for whole-genome-based phylogenetic clustering within the L2 open reading frame were identified. Multivariate logistic regression analysis revealed that lineage B predominated globally. Sublineage B3 was more common in Africa and North and South America, and lineage A was more common in Asia. Sublineages B1 and B3 were associated with anogenital infections, indicating a potential lesion-specific predilection of some HPV6 sublineages. Females had higher odds for infection with sublineage B3 than males. In conclusion, a global HPV6 phylogenetic analysis revealed the existence of two variant lineages and five sublineages, showing some degree of ethnogeographic, gender, and/or disease predilection in their distribution. IMPORTANCE This study established the largest database of globally circulating HPV6 genomic variants and contributed a total of 130 new, complete HPV6 genome sequences to available sequence repositories. Two HPV6 variant lineages and five sublineages were identified and showed some degree of association with geographical location, anatomical site of infection/disease, and/or gender. We additionally identified several HPV6 lineage- and sublineage-specific SNPs to facilitate the identification of HPV6 variants and determined a representative region within the L2 gene that is suitable for HPV6 whole-genome-based phylogenetic analysis. This study complements and significantly expands the current knowledge of HPV6 genetic diversity and forms a comprehensive basis for future epidemiological, evolutionary, functional, pathogenicity, vaccination, and molecular assay development studies.

Quantitative evaluation of video laryngostroboscopy: reliability of the basic parameters.

OBJECTIVE The purpose of this study was to evaluate quantitatively the basic parameters of the video laryngostroboscopy (VLS) and determine the sensitivity and specificity of these parameters discriminating healthy and pathological voice classes. METHODS Digital VLS recordings were performed for 159 individuals: 26 healthy and 133 patients. VLS variables (glottal closure, regularity, mucosal wave on the affected/healthy side, symmetry of vibration, and symmetry of image) were rated two times with the time interval of 1 year by three laryngologists. To evaluate interrater and test-retest reliability, intraclass correlation coefficients (ICCs) were calculated. To evaluate sensitivity and specificity of the VLS parameters, discriminant analysis was used. RESULTS Moderate to almost perfect levels (ICC 0.46-0.90) of interrater reliability were revealed for most of the basic VLS parameters. The ICC of the interrater reliability was highest for symmetry of glottal image; the most problematic VLS parameter for rating was mucosal wave on the healthy side. ICC of the test-retest reliability were 0.71-0.95, P<0.001. An optimum system of VLS parameters discriminating normal and pathological voice subgroups with sensitivity 96.3% and specificity 100% included glottal closure and mucosal wave on the affected side. CONCLUSIONS The quantitative evaluation of the VLS using basic parameters showed to be reliable in clinical settings and demonstrated high sensitivity and specificity distinguishing healthy and pathological voice patient groups.

Combining image, voice, and the patient's questionnaire data to categorize laryngeal disorders

OBJECTIVE This paper is concerned with soft computing techniques for categorizing laryngeal disorders based on information extracted from an image of patients vocal folds, a voice signal, and questionnaire data. METHODS Multiple feature sets are exploited to characterize images and voice signals. To characterize colour, texture, and geometry of biological structures seen in colour images of vocal folds, eight feature sets are used. Twelve feature sets are used to obtain a comprehensive characterization of a voice signal (the sustained phonation of the vowel sound /a/). Answers to 14 questions constitute the questionnaire feature set. A committee of support vector machines is designed for categorizing the image, voice, and query data represented by the multiple feature sets into the healthy, nodular and diffuse classes. Five alternatives to aggregate separate SVMs into a committee are explored. Feature selection and classifier design are combined into the same learning process based on genetic search. RESULTS Data of all the three modalities were available from 240 patients. Among those, 151 patients belong to the nodular class, 64 to the diffuse class and 25 to the healthy class. When using a single feature set to characterize each modality, the test set data classification accuracy of 75.0%, 72.1%, and 85.0% was obtained for the image, voice and questionnaire data, respectively. The use of multiple feature sets allowed to increase the accuracy to 89.5% and 87.7% for the image and voice data, respectively. The test set data classification accuracy of over 98.0% was obtained from a committee exploiting multiple feature sets from all the three modalities. The highest classification accuracy was achieved when using the SVM-based aggregation with hyper parameters of the SVM determined by genetic search. Bearing in mind the difficulty of the task, the obtained classification accuracy is rather encouraging. CONCLUSIONS Combination of both multiple feature sets characterizing a single modality and the three modalities allowed to substantially improve the classification accuracy if compared to the highest accuracy obtained from a single feature set and a single modality. In spite of the unbalanced data sets used, the error rates obtained for the three classes were rather similar.