Martin Chovanec - Academia.edu (original) (raw)

Papers by Martin Chovanec

Research paper thumbnail of Balloon dilatation of pediatric subglottic laryngeal stenosis during the artificial apneic pause: experience in 5 children

BioMed research international, 2014

Balloon dilatation is a method of choice for treatment of laryngeal stenosis in children. The aim... more Balloon dilatation is a method of choice for treatment of laryngeal stenosis in children. The aim of procedure in apneic pause is to avoid new insertion of tracheostomy cannula. The authors performed balloon dilatation of subglottic laryngeal strictures (SGS) in 5 children (3 girls and 2 boys) without tracheotomy. Two of them with traumatic and inflammatory SGS had a tracheal cannula removed in the past. The other 3 children with postintubation SGS had never had a tracheostomy before. The need for tracheostomy due to worsening stridor was imminent for all of them. The total of seven laryngeal dilatations by balloon esophagoplasty catheter in apneic pause was performed in the 5 children. The procedure averted the need for tracheostomy placement in 4 of them (80%). Failure of dilatation in girl with traumatic stenosis and concomitant severe obstructive lung disease led to repeated tracheostomy. Balloon dilatation of laryngeal stricture could be done in the absence of tracheostomy in a...

Research paper thumbnail of Comparative analysis of alpha2,3/2,6-linked N-acetylneuraminic acid and cytokeratin expression in head and neck squamous cell carcinoma

Oncology reports, 2004

Head and neck squamous cell cancer (HNSCC) requires precise characterization of their biological ... more Head and neck squamous cell cancer (HNSCC) requires precise characterization of their biological properties to better stratify treatment approaches. Some biological features of tumor cells are related to altered glycosylation of their surface. This study characterized alpha2,3/6-N-acetylneuraminic acid (NeuNAc) expression in adult squamous epithelia of primary and metastatic HNSCC in relation to expression of well established differentiation markers, such as cytokeratins. The expression of NeuNAc was assessed by plant lectins: Maackia amurensis agglutinin type 2 (MAA) and Sambucus nigra agglutinin (SNA) specific for alpha2,3NeuNAc and alpha2,6NeuNAc, respectively. Double labeling studies at the single-cell level were performed to compare alpha2,3/6NeuNAc linkage with expression of intermediate filaments. In studied normal adult epithelia, predominantly basal expression of alpha2,6NeuNAc and suprabasal expression of alpha2,3NeuNAc was seen, showing their differentiation-dependent lin...

Research paper thumbnail of P.80 Molecular marker of head and neck cancer —galectin-3?

Oral Oncology Supplement, 2005

stay, duration of enteral nutrition, costs related to antibiotic consumption, bacteriological ana... more stay, duration of enteral nutrition, costs related to antibiotic consumption, bacteriological analysis, and devices (nasogastric tubes, urinary catheters, venous central devices, gastrostomies). Results: Mean length of hospital stay was 34 days for patients wath WI and 21 days for pahents without WI. Assomated pneumopathms were observed m 10/49 and 21/119 (Odds Ratm = 1.2 [95%CI: 0.5-2.77]). Anhbmtlcs were requtred m 32/49 cases and23/119 (Odds Ratio = 7.9 [95%CI: 3.7-16.5]). Mean total direct costs were 39 558 Euros for patients with WI and 23 990 Euros for patients without WI. Hospital stay, enteral nutrition, bacteriological analysis, antibiotics and devices represented respectwely 98%, 0.5%, 0.33%, 0.17% and 0.06% of total dtrect costs. Conelnsion: WI associated with major head and neck cancer surgery costs about 15,000 Euros per patients. This spent is essenhally related to length of hospital stay.

Research paper thumbnail of Correlation of expression of nuclear proteins pKi67 and p63 with lectin histochemical features in head and neck squamous cell cancer

International Journal of Oncology, 2005

This study represents a combined lectin and immuno-histochemical analysis of normal, dysplastic a... more This study represents a combined lectin and immuno-histochemical analysis of normal, dysplastic and malignant squamous epithelia of the upper aerodigestive tract with emphasis on the relation between lectin reactivity and the cells' proliferative/anti-apoptotic potential. Staining by double-labeling to detect pKi67, DeltaNp63alpha, alpha2,3/6-linked sialic acid (NeuNAc) and galectin-3-reactive epitopes was performed on specimens of 8 normal cases, 27 primary tumours and 15 regional lymph node metastases. Normal epithelia expressed alpha2,6-linked NeuNAc in the basal layer, while alpha2,3-linked NeuNAc was observed in suprabasal layers. In normal epithelium pKi67 and DeltaNp63alpha positivity was seen in the basal layer and galectin-3-reactive sites in suprabasal layers. The studied squamous cell carcinomas and their metastases showed a tendency for stratification but with markedly altered architecture. The expression of the studied markers was heterogeneous between the different cancer cases but comparable between the corresponding primary and secondary lesions. Glycophenotypic properties were correlated with the level of differentiation. Tumour cell populations were characterized by occurrence of the p63+/pKi67+ alpha2,3-NeuNAc+ alpha2,6-NeuNAc+ phenotype. Analysis of the expression patterns of pKi67, p63 and galectin-3-reactive epitopes (Gal-3-RE) delineated statistically significant interrelationships (Gal-3-RE vs. p63: r = -0.709; Gal-3-RE vs. pKi67: r = -0.623; pKi67 vs. p63: r = 0.895). Of the studied markers only Gal-3-RE expression was correlated to the differentiation-dependent grading (G1 vs. G2: p = 0.007, G2 vs. G3: p = 0.006, G1 vs. G3: p = 0.002). DeltaNp63alpha expression was statistically different only between G1 and G3 (p = 0.03). No statistically significant differences were detected between the primary tumours and the corresponding regional lymph node metastases. Based on the concept of the sugar code further analysis of cell characteristics such as proliferation together with lectin histochemical features, especially using tissue lectins as probes, is thus warranted.

Research paper thumbnail of Thyroid carcinoma surgery in children and adolescents – 15 years experience surgery of pediatric thyroid carcinoma

International Journal of Pediatric Otorhinolaryngology, 2014

Research paper thumbnail of Narrow Band Imaging (NBI) — Endoscopic Method for Detection of Head and Neck Cancer

Research paper thumbnail of Complications of Microsurgery of Vestibular Schwannoma

BioMed Research International, 2014

Background. The aim of this study was to analyze complications of vestibular schwannoma (VS) micr... more Background. The aim of this study was to analyze complications of vestibular schwannoma (VS) microsurgery. Material and Methods. A retrospective study was performed in 333 patients with unilateral vestibular schwannoma indicated for surgical treatment between January 1997 and December 2012. Postoperative complications were assessed immediately after VS surgery as well as during outpatient followup. Results. In all 333 patients microsurgical vestibular schwannoma (Koos grade 1: 12, grade 2: 34, grade 3: 62, and grade 4: 225) removal was performed. The main neurological complication was facial nerve dysfunction. The intermediate and poor function (HB III-VI) was observed in 124 cases (45%) immediately after surgery and in 104 cases (33%) on the last followup. We encountered disordered vestibular compensation in 13%, permanent trigeminal nerve dysfunction in 1%, and transient lower cranial nerves (IX-XI) deficit in 6%. Nonneurological complications included CSF leakage in 63% (lateral/medial variant: 99/1%), headache in 9%, and intracerebral hemorrhage in 5%. We did not encounter any case of meningitis. Conclusions. Our study demonstrates that despite the benefits of advanced high-tech equipment, refined microsurgical instruments, and highly developed neuroimaging technologies, there are still various and significant complications associated with vestibular schwannomas microsurgery.

Research paper thumbnail of Does Attempt at Hearing Preservation Microsurgery of Vestibular Schwannoma Affect Postoperative Tinnitus?

BioMed Research International, 2015

Background. The aim of this study was to analyze the effect of vestibular schwannoma microsurgery... more Background. The aim of this study was to analyze the effect of vestibular schwannoma microsurgery via the retrosigmoidtransmeatal approach with special reference to the postoperative tinnitus outcome. Material and Methods. A prospective study was performed in 89 consecutive patients with unilateral vestibular schwannoma indicated for microsurgery. Patient and tumor related parameters, pre-and postoperative hearing level, intraoperative findings, and hearing and tinnitus handicap inventory scores were analyzed. Results. Cochlear nerve integrity was achieved in 44% corresponding to preservation of preoperatively serviceable hearing in 47% and useful hearing in 21%. Main prognostic factors of hearing preservation were grade/size of tumor, preoperative hearing level, intraoperative neuromonitoring, tumor consistency, and adhesion to neurovascular structures. Microsurgery led to elimination of tinnitus in 66% but also new-onset of the symptom in 14% of cases. Preservation of useful hearing and neurectomy of the eighth cranial nerve were main prognostic factors of tinnitus elimination. Preservation of cochlear nerve but loss of preoperative hearing emerged as the main factor for tinnitus persistence and new onset tinnitus. Decrease of THI scores was observed postoperatively. Conclusions. Our results underscore the importance of proper pre-and intraoperative decision making about attempt at hearing preservation versus potential for tinnitus elimination/risk of new onset of tinnitus.

Research paper thumbnail of Microsurgical Treatment of Meningiomas of the Cerebellopontine Angle with Internal Auditory Canal Extension

Research paper thumbnail of Small Vestibular Schwannomas (Grades I and II): Wait and Scan, Stereotactic Radiosurgery, or Microsurgery?

Research paper thumbnail of Glycobiology of Head and Neck Squamous Epithelia and Carcinomas

ORL, 2005

An impressive variety of regulatory processes including cell adhesion and migration, proliferatio... more An impressive variety of regulatory processes including cell adhesion and migration, proliferation, apoptosis and differentiation folding and routing of glycoproteins have been found to be mediated by specific lectin-carbohydrate interactions. This article summarizes the data on glycobiological aspects of differentiation of squamous epithelia in the head and neck region under physiological conditions and in cancer. The possible function of lectins in tumor development and invasiveness is debated. Introduction of labeled endogenous lectins as a tool for the study of functional glycomics at the cellular level in head and neck squamous epithelia and carcinomas enables a complex interpretation of studied data because these lectins are normally occurring in these tissues. The lectinology of Langerhans cells in head and neck squamous epithelia and carcinoma is also mentioned. Finally, the use of the described data in the diagnosis and prospectively in the treatment of head and neck squamous cell carcinoma is shown.

Research paper thumbnail of Surgery of Tumors of the Parapharyngeal Space

Research paper thumbnail of Nuclear presence of adhesion-/growth-regulatory galectins in normal/malignant cells of squamous epithelial origin

Histochemistry and Cell Biology, 2006

Cellular activities in the regulation of growth or adhesion/migration involve protein (lectin)–ca... more Cellular activities in the regulation of growth or adhesion/migration involve protein (lectin)–carbohydrate recognition at the cell surface. Members of the galectin family of endogenous lectins additionally bind distinct intracellular ligands. These interactions with protein targets explain the relevance of their nuclear and cytoplasmic presence. Expression profiling for galectins and accessible binding sites is a histochemical approach to link localization with

Research paper thumbnail of Minimally Invasive Video-Assisted versus Minimally Invasive Nonendoscopic Thyroidectomy

BioMed Research International, 2014

Minimally invasive video-assisted thyroidectomy (MIVAT) and minimally invasive nonendoscopic thyr... more Minimally invasive video-assisted thyroidectomy (MIVAT) and minimally invasive nonendoscopic thyroidectomy (MINET) represent well accepted and reproducible techniques developed with the main goal to improve cosmetic outcome, accelerate healing, and increase patient's comfort following thyroid surgery. Between 2007 and 2011, a prospective nonrandomized study of patients undergoing minimally invasive thyroid surgery was performed to compare advantages and disadvantages of the two different techniques. There were no significant differences in the length of incision to perform surgical procedures. Mean duration of hemithyroidectomy was comparable in both groups, but it was more time consuming to perform total thyroidectomy by MIVAT. There were more patients undergoing MIVAT procedures without active drainage in the postoperative course and we also could see a trend for less pain in the same group. This was paralleled by statistically significant decreased administration of both opiates and nonopiate analgesics. We encountered two cases of recurrent laryngeal nerve palsies in the MIVAT group only. MIVAT and MINET represent safe and feasible alternative to conventional thyroid surgery in selected cases and this prospective study has shown minimal differences between these two techniques.

Research paper thumbnail of The Role of NBI HDTV Magnifying Endoscopy in the Prehistologic Diagnosis of Laryngeal Papillomatosis and Spinocellular Cancer

BioMed Research International, 2014

Narrow band imaging (NBI) HDTV (high definition television) magnifying endoscopy is considered to... more Narrow band imaging (NBI) HDTV (high definition television) magnifying endoscopy is considered to be superior for the accurate display of the microvascular patterns of superficial mucosal lesions. Observation of changes in intraepithelial papillary capillary loops (IPCL) can help distinguish benign from malignant lesions as part of an "optical biopsy. " However, IPCL changes in papillomas may be mistaken for spinocellular cancer (SCC). The aim of the study was to determine whether observing microvascular changes alone is sufficient for discriminating between laryngeal SCC and papillomatosis. An additional aim was to identify associated characteristics that could clarify the diagnosis. The study included 109 patients with a suspected laryngeal tumor or papilloma. HDTV NBI magnifying endoscopy was performed during direct laryngoscopy. It was possible to visualize IPCL changes in 82 out of 109 patients (75.2%). In 71 (86.6%) patients, the diagnosis was correctly determined. In 4 (4.9%) cases, the diagnosis of SCC was expressed on the basis of finding pathologic IPCL, but histology did not demonstrate malignancy. To achieve a correct diagnosis using HDTV NBI magnifying endoscopy, it is important not only to observe changes in the shape of IPCL but also to note possible papillary structures with central-axis capillaries typical of papillomatosis.

Research paper thumbnail of Microarray Analysis of Serum mRNA in Patients with Head and Neck Squamous Cell Carcinoma at Whole-Genome Scale

BioMed Research International, 2014

With the increasing demand for noninvasive approaches in monitoring head and neck cancer, circula... more With the increasing demand for noninvasive approaches in monitoring head and neck cancer, circulating nucleic acids have been shown to be a promising tool. We focused on the global transcriptome of serum samples of head and neck squamous cell carcinoma (HNSCC) patients in comparison with healthy individuals. We compared gene expression patterns of 36 samples. Twenty-four participants including 16 HNSCC patients (from 12 patients we obtained blood samples 1 year posttreatment) and 8 control subjects were recruited. The Illumina HumanWG-6 v3 Expression BeadChip was used to profile and identify the differences in serum mRNA transcriptomes. We found 159 genes to be significantly changed (Storey's value < 0.05) between normal and cancer serum specimens regardless of factors including p53 and B-cell lymphoma family members (Bcl-2, Bcl-XL). In contrast, there was no difference in gene expression between samples obtained before and after surgery in cancer patients. We suggest that microarray analysis of serum cRNA in patients with HNSCC should be suitable for refinement of early stage diagnosis of disease that can be important for development of new personalized strategies in diagnosis and treatment of tumours but is not suitable for monitoring further development of disease.

Research paper thumbnail of Comparative phenotypic characterization of keratinocytes originating from hair follicles

Journal of Molecular Histology, 2005

The principal pool of epidermal stem cells is located in the bulge region of the hair follicle ro... more The principal pool of epidermal stem cells is located in the bulge region of the hair follicle root sheath. In this research project, we have used a refined procedure to isolate porcine hair follicles including their root sheath and for comparison purposes also human cell material. These cells migrating from the hair follicles were then cytochemically characterized. A panel of antibodies and two labeled plant lectins were tested on cell material obtained under a range of assorted experimental conditions. Due to their role in growth regulation we also studied two endogenous lectins, specifically monitoring their expression and the presence of accessible ligands. These in vitro results were compared with findings on porcine and human hair follicles and human basal cell carcinomas in situ. The keratinocytes originating from hair follicles in the presence of feeder cells are rather undifferentiated and express galectin-1/galectin-1-binding sites but not galectin-3 in their nuclei associated with DNp63a positivity. Nuclear reactivity for galectin-1 was rarely observed in the bulge of the outer root sheath of the human hair follicle and of basal cell carcinomas and absent in porcine tissue samples. Exclusion of feeder cells from our cultivation system of porcine hair follicles led to the formation of spheroid bodies from these keratinocytes. Ki67 as a marker of proliferation was not present in the nuclei of cells forming these spheroids. One part of these bodies is positive for markers of post-mitotic differentiated cells, while the other spheroids are composed of poorly differentiated cells, which are able to adhere to feeder cells and form growing colonies. In summary, the detection of galectin-1 and also nuclear binding sites for this endogenous effector points to intracellular functionality of this lectin. It can be considered a potential marker of a distinct cell population, probably at the beginning of a differentiation cascade of keratinocytes. J Mol Hist (2005) 36:89-96 Ó Springer 2005

Research paper thumbnail of Regulatory T cells and their prognostic value for patients with squamous cell carcinoma of the head and neck

Journal of Cellular and Molecular Medicine, 2010

Regulatory T lymphocytes (Treg) represent one of the most important mechanisms of peripheral immu... more Regulatory T lymphocytes (Treg) represent one of the most important mechanisms of peripheral immune tolerance, which is employed to safeguard any over-activations of the immune system. It has been shown that interleukin (IL)-2 is vital for growth and differentiation of Treg . It is worth noting that surface expression of the IL-2 receptor ␣, CD25, is not unique for Treg, and that activated conventional T cells also express CD25. Nonetheless, Treg represent a major population within the CD4 ϩ CD25 hi T cells repertoire in healthy individuals.

Research paper thumbnail of Marker profiling of normal keratinocytes identifies the stroma from squamous cell carcinoma of the oral cavity as a modulatory microenvironment in co-culture

International Journal of Radiation Biology, 2007

The microenvironment established by stromal cells may or may not influence phenotypic aspects of ... more The microenvironment established by stromal cells may or may not influence phenotypic aspects of epithelial cells and may be relevant for tumor and stem cell biology. We address this issue for keratinocytes using tumor-derived stromal cells in a co-culture system. We isolated stromal cells from human squamous cell carcinoma tissue and studied their effect on phenotypic characteristics of normal human interfollicular keratinocytes in vitro. Stromal fibroblasts significantly influence immuno- and lectin cytochemical properties of co-cultured normal keratinocytes. Expression of keratins 8 and 19, the nucleolar protein nucleostemin, parameters related to adhesion/growth-regulatory galectins and the epithelial-mesenchymal transition were altered. This biological activity of tumor-derived stromal cells, which did not require cell contact, appeared to be stable, because it was maintained during passaging of keratinocytes in the absence of cancer cells. Tumor-derived stromal fibroblasts acquire distinct properties to shape a microenvironment conducive to altering the phenotypic characteristics of normal epithelial cells in vitro.

Research paper thumbnail of Head and neck squamous cancer stromal fibroblasts produce growth factors influencing phenotype of normal human keratinocytes

Histochemistry and Cell Biology, 2010

Epithelial-mesenchymal interaction between stromal fibroblasts and cancer cells influences the fu... more Epithelial-mesenchymal interaction between stromal fibroblasts and cancer cells influences the functional properties of tumor epithelium, including the tumor progression and spread. We compared fibroblasts prepared from stroma of squamous cell carcinoma and normal dermal fibroblasts concerning their biological activity toward normal keratinocytes assessed by immunocytochemistry and profiling of gene activation for growth factors/ cytokines by microarray chip technology. IGF-2 and BMP-4 were determined as candidate factors responsible for tumor-associated fibroblast activity that influences normal epithelia. This effect was confirmed by addition of recombinant IGF-2 and BMP4, respectively, to the culture medium. This hypothesis was also verified by inhibition experiments where blocking antibodies were employed in the medium conditioned by cancer-associated fibroblast. Presence of these growth factors was also detected in tumor samples.

Research paper thumbnail of Balloon dilatation of pediatric subglottic laryngeal stenosis during the artificial apneic pause: experience in 5 children

BioMed research international, 2014

Balloon dilatation is a method of choice for treatment of laryngeal stenosis in children. The aim... more Balloon dilatation is a method of choice for treatment of laryngeal stenosis in children. The aim of procedure in apneic pause is to avoid new insertion of tracheostomy cannula. The authors performed balloon dilatation of subglottic laryngeal strictures (SGS) in 5 children (3 girls and 2 boys) without tracheotomy. Two of them with traumatic and inflammatory SGS had a tracheal cannula removed in the past. The other 3 children with postintubation SGS had never had a tracheostomy before. The need for tracheostomy due to worsening stridor was imminent for all of them. The total of seven laryngeal dilatations by balloon esophagoplasty catheter in apneic pause was performed in the 5 children. The procedure averted the need for tracheostomy placement in 4 of them (80%). Failure of dilatation in girl with traumatic stenosis and concomitant severe obstructive lung disease led to repeated tracheostomy. Balloon dilatation of laryngeal stricture could be done in the absence of tracheostomy in a...

Research paper thumbnail of Comparative analysis of alpha2,3/2,6-linked N-acetylneuraminic acid and cytokeratin expression in head and neck squamous cell carcinoma

Oncology reports, 2004

Head and neck squamous cell cancer (HNSCC) requires precise characterization of their biological ... more Head and neck squamous cell cancer (HNSCC) requires precise characterization of their biological properties to better stratify treatment approaches. Some biological features of tumor cells are related to altered glycosylation of their surface. This study characterized alpha2,3/6-N-acetylneuraminic acid (NeuNAc) expression in adult squamous epithelia of primary and metastatic HNSCC in relation to expression of well established differentiation markers, such as cytokeratins. The expression of NeuNAc was assessed by plant lectins: Maackia amurensis agglutinin type 2 (MAA) and Sambucus nigra agglutinin (SNA) specific for alpha2,3NeuNAc and alpha2,6NeuNAc, respectively. Double labeling studies at the single-cell level were performed to compare alpha2,3/6NeuNAc linkage with expression of intermediate filaments. In studied normal adult epithelia, predominantly basal expression of alpha2,6NeuNAc and suprabasal expression of alpha2,3NeuNAc was seen, showing their differentiation-dependent lin...

Research paper thumbnail of P.80 Molecular marker of head and neck cancer —galectin-3?

Oral Oncology Supplement, 2005

stay, duration of enteral nutrition, costs related to antibiotic consumption, bacteriological ana... more stay, duration of enteral nutrition, costs related to antibiotic consumption, bacteriological analysis, and devices (nasogastric tubes, urinary catheters, venous central devices, gastrostomies). Results: Mean length of hospital stay was 34 days for patients wath WI and 21 days for pahents without WI. Assomated pneumopathms were observed m 10/49 and 21/119 (Odds Ratm = 1.2 [95%CI: 0.5-2.77]). Anhbmtlcs were requtred m 32/49 cases and23/119 (Odds Ratio = 7.9 [95%CI: 3.7-16.5]). Mean total direct costs were 39 558 Euros for patients with WI and 23 990 Euros for patients without WI. Hospital stay, enteral nutrition, bacteriological analysis, antibiotics and devices represented respectwely 98%, 0.5%, 0.33%, 0.17% and 0.06% of total dtrect costs. Conelnsion: WI associated with major head and neck cancer surgery costs about 15,000 Euros per patients. This spent is essenhally related to length of hospital stay.

Research paper thumbnail of Correlation of expression of nuclear proteins pKi67 and p63 with lectin histochemical features in head and neck squamous cell cancer

International Journal of Oncology, 2005

This study represents a combined lectin and immuno-histochemical analysis of normal, dysplastic a... more This study represents a combined lectin and immuno-histochemical analysis of normal, dysplastic and malignant squamous epithelia of the upper aerodigestive tract with emphasis on the relation between lectin reactivity and the cells&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; proliferative/anti-apoptotic potential. Staining by double-labeling to detect pKi67, DeltaNp63alpha, alpha2,3/6-linked sialic acid (NeuNAc) and galectin-3-reactive epitopes was performed on specimens of 8 normal cases, 27 primary tumours and 15 regional lymph node metastases. Normal epithelia expressed alpha2,6-linked NeuNAc in the basal layer, while alpha2,3-linked NeuNAc was observed in suprabasal layers. In normal epithelium pKi67 and DeltaNp63alpha positivity was seen in the basal layer and galectin-3-reactive sites in suprabasal layers. The studied squamous cell carcinomas and their metastases showed a tendency for stratification but with markedly altered architecture. The expression of the studied markers was heterogeneous between the different cancer cases but comparable between the corresponding primary and secondary lesions. Glycophenotypic properties were correlated with the level of differentiation. Tumour cell populations were characterized by occurrence of the p63+/pKi67+ alpha2,3-NeuNAc+ alpha2,6-NeuNAc+ phenotype. Analysis of the expression patterns of pKi67, p63 and galectin-3-reactive epitopes (Gal-3-RE) delineated statistically significant interrelationships (Gal-3-RE vs. p63: r = -0.709; Gal-3-RE vs. pKi67: r = -0.623; pKi67 vs. p63: r = 0.895). Of the studied markers only Gal-3-RE expression was correlated to the differentiation-dependent grading (G1 vs. G2: p = 0.007, G2 vs. G3: p = 0.006, G1 vs. G3: p = 0.002). DeltaNp63alpha expression was statistically different only between G1 and G3 (p = 0.03). No statistically significant differences were detected between the primary tumours and the corresponding regional lymph node metastases. Based on the concept of the sugar code further analysis of cell characteristics such as proliferation together with lectin histochemical features, especially using tissue lectins as probes, is thus warranted.

Research paper thumbnail of Thyroid carcinoma surgery in children and adolescents – 15 years experience surgery of pediatric thyroid carcinoma

International Journal of Pediatric Otorhinolaryngology, 2014

Research paper thumbnail of Narrow Band Imaging (NBI) — Endoscopic Method for Detection of Head and Neck Cancer

Research paper thumbnail of Complications of Microsurgery of Vestibular Schwannoma

BioMed Research International, 2014

Background. The aim of this study was to analyze complications of vestibular schwannoma (VS) micr... more Background. The aim of this study was to analyze complications of vestibular schwannoma (VS) microsurgery. Material and Methods. A retrospective study was performed in 333 patients with unilateral vestibular schwannoma indicated for surgical treatment between January 1997 and December 2012. Postoperative complications were assessed immediately after VS surgery as well as during outpatient followup. Results. In all 333 patients microsurgical vestibular schwannoma (Koos grade 1: 12, grade 2: 34, grade 3: 62, and grade 4: 225) removal was performed. The main neurological complication was facial nerve dysfunction. The intermediate and poor function (HB III-VI) was observed in 124 cases (45%) immediately after surgery and in 104 cases (33%) on the last followup. We encountered disordered vestibular compensation in 13%, permanent trigeminal nerve dysfunction in 1%, and transient lower cranial nerves (IX-XI) deficit in 6%. Nonneurological complications included CSF leakage in 63% (lateral/medial variant: 99/1%), headache in 9%, and intracerebral hemorrhage in 5%. We did not encounter any case of meningitis. Conclusions. Our study demonstrates that despite the benefits of advanced high-tech equipment, refined microsurgical instruments, and highly developed neuroimaging technologies, there are still various and significant complications associated with vestibular schwannomas microsurgery.

Research paper thumbnail of Does Attempt at Hearing Preservation Microsurgery of Vestibular Schwannoma Affect Postoperative Tinnitus?

BioMed Research International, 2015

Background. The aim of this study was to analyze the effect of vestibular schwannoma microsurgery... more Background. The aim of this study was to analyze the effect of vestibular schwannoma microsurgery via the retrosigmoidtransmeatal approach with special reference to the postoperative tinnitus outcome. Material and Methods. A prospective study was performed in 89 consecutive patients with unilateral vestibular schwannoma indicated for microsurgery. Patient and tumor related parameters, pre-and postoperative hearing level, intraoperative findings, and hearing and tinnitus handicap inventory scores were analyzed. Results. Cochlear nerve integrity was achieved in 44% corresponding to preservation of preoperatively serviceable hearing in 47% and useful hearing in 21%. Main prognostic factors of hearing preservation were grade/size of tumor, preoperative hearing level, intraoperative neuromonitoring, tumor consistency, and adhesion to neurovascular structures. Microsurgery led to elimination of tinnitus in 66% but also new-onset of the symptom in 14% of cases. Preservation of useful hearing and neurectomy of the eighth cranial nerve were main prognostic factors of tinnitus elimination. Preservation of cochlear nerve but loss of preoperative hearing emerged as the main factor for tinnitus persistence and new onset tinnitus. Decrease of THI scores was observed postoperatively. Conclusions. Our results underscore the importance of proper pre-and intraoperative decision making about attempt at hearing preservation versus potential for tinnitus elimination/risk of new onset of tinnitus.

Research paper thumbnail of Microsurgical Treatment of Meningiomas of the Cerebellopontine Angle with Internal Auditory Canal Extension

Research paper thumbnail of Small Vestibular Schwannomas (Grades I and II): Wait and Scan, Stereotactic Radiosurgery, or Microsurgery?

Research paper thumbnail of Glycobiology of Head and Neck Squamous Epithelia and Carcinomas

ORL, 2005

An impressive variety of regulatory processes including cell adhesion and migration, proliferatio... more An impressive variety of regulatory processes including cell adhesion and migration, proliferation, apoptosis and differentiation folding and routing of glycoproteins have been found to be mediated by specific lectin-carbohydrate interactions. This article summarizes the data on glycobiological aspects of differentiation of squamous epithelia in the head and neck region under physiological conditions and in cancer. The possible function of lectins in tumor development and invasiveness is debated. Introduction of labeled endogenous lectins as a tool for the study of functional glycomics at the cellular level in head and neck squamous epithelia and carcinomas enables a complex interpretation of studied data because these lectins are normally occurring in these tissues. The lectinology of Langerhans cells in head and neck squamous epithelia and carcinoma is also mentioned. Finally, the use of the described data in the diagnosis and prospectively in the treatment of head and neck squamous cell carcinoma is shown.

Research paper thumbnail of Surgery of Tumors of the Parapharyngeal Space

Research paper thumbnail of Nuclear presence of adhesion-/growth-regulatory galectins in normal/malignant cells of squamous epithelial origin

Histochemistry and Cell Biology, 2006

Cellular activities in the regulation of growth or adhesion/migration involve protein (lectin)–ca... more Cellular activities in the regulation of growth or adhesion/migration involve protein (lectin)–carbohydrate recognition at the cell surface. Members of the galectin family of endogenous lectins additionally bind distinct intracellular ligands. These interactions with protein targets explain the relevance of their nuclear and cytoplasmic presence. Expression profiling for galectins and accessible binding sites is a histochemical approach to link localization with

Research paper thumbnail of Minimally Invasive Video-Assisted versus Minimally Invasive Nonendoscopic Thyroidectomy

BioMed Research International, 2014

Minimally invasive video-assisted thyroidectomy (MIVAT) and minimally invasive nonendoscopic thyr... more Minimally invasive video-assisted thyroidectomy (MIVAT) and minimally invasive nonendoscopic thyroidectomy (MINET) represent well accepted and reproducible techniques developed with the main goal to improve cosmetic outcome, accelerate healing, and increase patient's comfort following thyroid surgery. Between 2007 and 2011, a prospective nonrandomized study of patients undergoing minimally invasive thyroid surgery was performed to compare advantages and disadvantages of the two different techniques. There were no significant differences in the length of incision to perform surgical procedures. Mean duration of hemithyroidectomy was comparable in both groups, but it was more time consuming to perform total thyroidectomy by MIVAT. There were more patients undergoing MIVAT procedures without active drainage in the postoperative course and we also could see a trend for less pain in the same group. This was paralleled by statistically significant decreased administration of both opiates and nonopiate analgesics. We encountered two cases of recurrent laryngeal nerve palsies in the MIVAT group only. MIVAT and MINET represent safe and feasible alternative to conventional thyroid surgery in selected cases and this prospective study has shown minimal differences between these two techniques.

Research paper thumbnail of The Role of NBI HDTV Magnifying Endoscopy in the Prehistologic Diagnosis of Laryngeal Papillomatosis and Spinocellular Cancer

BioMed Research International, 2014

Narrow band imaging (NBI) HDTV (high definition television) magnifying endoscopy is considered to... more Narrow band imaging (NBI) HDTV (high definition television) magnifying endoscopy is considered to be superior for the accurate display of the microvascular patterns of superficial mucosal lesions. Observation of changes in intraepithelial papillary capillary loops (IPCL) can help distinguish benign from malignant lesions as part of an "optical biopsy. " However, IPCL changes in papillomas may be mistaken for spinocellular cancer (SCC). The aim of the study was to determine whether observing microvascular changes alone is sufficient for discriminating between laryngeal SCC and papillomatosis. An additional aim was to identify associated characteristics that could clarify the diagnosis. The study included 109 patients with a suspected laryngeal tumor or papilloma. HDTV NBI magnifying endoscopy was performed during direct laryngoscopy. It was possible to visualize IPCL changes in 82 out of 109 patients (75.2%). In 71 (86.6%) patients, the diagnosis was correctly determined. In 4 (4.9%) cases, the diagnosis of SCC was expressed on the basis of finding pathologic IPCL, but histology did not demonstrate malignancy. To achieve a correct diagnosis using HDTV NBI magnifying endoscopy, it is important not only to observe changes in the shape of IPCL but also to note possible papillary structures with central-axis capillaries typical of papillomatosis.

Research paper thumbnail of Microarray Analysis of Serum mRNA in Patients with Head and Neck Squamous Cell Carcinoma at Whole-Genome Scale

BioMed Research International, 2014

With the increasing demand for noninvasive approaches in monitoring head and neck cancer, circula... more With the increasing demand for noninvasive approaches in monitoring head and neck cancer, circulating nucleic acids have been shown to be a promising tool. We focused on the global transcriptome of serum samples of head and neck squamous cell carcinoma (HNSCC) patients in comparison with healthy individuals. We compared gene expression patterns of 36 samples. Twenty-four participants including 16 HNSCC patients (from 12 patients we obtained blood samples 1 year posttreatment) and 8 control subjects were recruited. The Illumina HumanWG-6 v3 Expression BeadChip was used to profile and identify the differences in serum mRNA transcriptomes. We found 159 genes to be significantly changed (Storey's value < 0.05) between normal and cancer serum specimens regardless of factors including p53 and B-cell lymphoma family members (Bcl-2, Bcl-XL). In contrast, there was no difference in gene expression between samples obtained before and after surgery in cancer patients. We suggest that microarray analysis of serum cRNA in patients with HNSCC should be suitable for refinement of early stage diagnosis of disease that can be important for development of new personalized strategies in diagnosis and treatment of tumours but is not suitable for monitoring further development of disease.

Research paper thumbnail of Comparative phenotypic characterization of keratinocytes originating from hair follicles

Journal of Molecular Histology, 2005

The principal pool of epidermal stem cells is located in the bulge region of the hair follicle ro... more The principal pool of epidermal stem cells is located in the bulge region of the hair follicle root sheath. In this research project, we have used a refined procedure to isolate porcine hair follicles including their root sheath and for comparison purposes also human cell material. These cells migrating from the hair follicles were then cytochemically characterized. A panel of antibodies and two labeled plant lectins were tested on cell material obtained under a range of assorted experimental conditions. Due to their role in growth regulation we also studied two endogenous lectins, specifically monitoring their expression and the presence of accessible ligands. These in vitro results were compared with findings on porcine and human hair follicles and human basal cell carcinomas in situ. The keratinocytes originating from hair follicles in the presence of feeder cells are rather undifferentiated and express galectin-1/galectin-1-binding sites but not galectin-3 in their nuclei associated with DNp63a positivity. Nuclear reactivity for galectin-1 was rarely observed in the bulge of the outer root sheath of the human hair follicle and of basal cell carcinomas and absent in porcine tissue samples. Exclusion of feeder cells from our cultivation system of porcine hair follicles led to the formation of spheroid bodies from these keratinocytes. Ki67 as a marker of proliferation was not present in the nuclei of cells forming these spheroids. One part of these bodies is positive for markers of post-mitotic differentiated cells, while the other spheroids are composed of poorly differentiated cells, which are able to adhere to feeder cells and form growing colonies. In summary, the detection of galectin-1 and also nuclear binding sites for this endogenous effector points to intracellular functionality of this lectin. It can be considered a potential marker of a distinct cell population, probably at the beginning of a differentiation cascade of keratinocytes. J Mol Hist (2005) 36:89-96 Ó Springer 2005

Research paper thumbnail of Regulatory T cells and their prognostic value for patients with squamous cell carcinoma of the head and neck

Journal of Cellular and Molecular Medicine, 2010

Regulatory T lymphocytes (Treg) represent one of the most important mechanisms of peripheral immu... more Regulatory T lymphocytes (Treg) represent one of the most important mechanisms of peripheral immune tolerance, which is employed to safeguard any over-activations of the immune system. It has been shown that interleukin (IL)-2 is vital for growth and differentiation of Treg . It is worth noting that surface expression of the IL-2 receptor ␣, CD25, is not unique for Treg, and that activated conventional T cells also express CD25. Nonetheless, Treg represent a major population within the CD4 ϩ CD25 hi T cells repertoire in healthy individuals.

Research paper thumbnail of Marker profiling of normal keratinocytes identifies the stroma from squamous cell carcinoma of the oral cavity as a modulatory microenvironment in co-culture

International Journal of Radiation Biology, 2007

The microenvironment established by stromal cells may or may not influence phenotypic aspects of ... more The microenvironment established by stromal cells may or may not influence phenotypic aspects of epithelial cells and may be relevant for tumor and stem cell biology. We address this issue for keratinocytes using tumor-derived stromal cells in a co-culture system. We isolated stromal cells from human squamous cell carcinoma tissue and studied their effect on phenotypic characteristics of normal human interfollicular keratinocytes in vitro. Stromal fibroblasts significantly influence immuno- and lectin cytochemical properties of co-cultured normal keratinocytes. Expression of keratins 8 and 19, the nucleolar protein nucleostemin, parameters related to adhesion/growth-regulatory galectins and the epithelial-mesenchymal transition were altered. This biological activity of tumor-derived stromal cells, which did not require cell contact, appeared to be stable, because it was maintained during passaging of keratinocytes in the absence of cancer cells. Tumor-derived stromal fibroblasts acquire distinct properties to shape a microenvironment conducive to altering the phenotypic characteristics of normal epithelial cells in vitro.

Research paper thumbnail of Head and neck squamous cancer stromal fibroblasts produce growth factors influencing phenotype of normal human keratinocytes

Histochemistry and Cell Biology, 2010

Epithelial-mesenchymal interaction between stromal fibroblasts and cancer cells influences the fu... more Epithelial-mesenchymal interaction between stromal fibroblasts and cancer cells influences the functional properties of tumor epithelium, including the tumor progression and spread. We compared fibroblasts prepared from stroma of squamous cell carcinoma and normal dermal fibroblasts concerning their biological activity toward normal keratinocytes assessed by immunocytochemistry and profiling of gene activation for growth factors/ cytokines by microarray chip technology. IGF-2 and BMP-4 were determined as candidate factors responsible for tumor-associated fibroblast activity that influences normal epithelia. This effect was confirmed by addition of recombinant IGF-2 and BMP4, respectively, to the culture medium. This hypothesis was also verified by inhibition experiments where blocking antibodies were employed in the medium conditioned by cancer-associated fibroblast. Presence of these growth factors was also detected in tumor samples.