Publications by authors named "Jan Stembirek"

Squamous cell carcinoma (SCC) of the head and neck originates from the mucosal lining of the upper aerodigestive tract, including the lip, tongue, nasopharynx, oropharynx, larynx and hypopharynx. In this review, we summarise what is currently known about the potential function of primary cilia in the pathogenesis of this disease. As primary cilia represent a key cellular structure for signal transduction and are related to cell proliferation, an understanding of their role in carcinogenesis is necessary for the design of new treatment approaches.

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This contribution gives basic information about the mechanical behavior of the facial part of the human skull cranium, i.e., the splanchnocranium, associated with external loads and injuries caused mainly by brachial violence.

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Article Synopsis
  • * A cohort of 55 patients was followed for a median of nearly 20 months, revealing an overall survival rate of about 61.8% and a disease-specific survival rate of 72.7%, with significant correlations found between high PD-L1 expression and better survival outcomes.
  • * The findings suggest that combining high PD-L1 expression with either increased CD8+ TIL counts or higher TIL density could serve as a strong prognostic factor for patient outcomes, indicating
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Objective: Oral squamous cell carcinoma (OSCC) originates from the mucosal lining of the oral cavity. Almost half of newly diagnosed cases are classified as advanced stage IV disease, which makes resection difficult. In this study, we investigated the pathological features and mutation profiles of tumor margins in OSCC.

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Background: Ameloblastic carcinoma and metastasising ameloblastoma are rare epithelial odontogenic tumours with aggressive features. Distinguishing between these two lesions is often clinically difficult but necessary to predict tumour behaviour or to plan future therapy. Here, we provide a brief review of the literature available on these two types of lesions and present a new case report of a young man with an ameloblastoma displaying metastatic features.

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Developmental cysts are pathological epithelial-lined cavities arising in various organs as a result of systemic or hereditary diseases. Molecular mechanisms involved in the formation of developmental odontogenic cysts (OCs) are not fully understood yet; the cystogenesis of renal cysts originating from the autosomal dominant polycystic kidney disease (ADPKD) has been, however, explored in much greater detail. This narrative review aimed i) to summarize molecular and cellular processes involved in the formation and growth of developmental OCs, especially dentigerous cysts (DCs) and odontogenic keratocysts (OKCs), ii) to find if there are any similarities in their cystogenesis to ADPKD cysts, and, based on that, iii) to suggest potential factors, candidate molecules, and mechanisms that could be involved in the DC formation, thus proposing further research directions.

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Introduction: The incidence of advanced oral cavity and oropharyngeal cancers is generally high. Treatment outcomes for patients, especially those unfit for comprehensive cancer treatment, are unsatisfactory. Therefore, the search for factors to predict response to treatment and increase overall survival is underway.

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Objectives: Primary cilium is a cellular organelle with growing significance confirmed in tumour biology. Primary cilia have been associated with fine tuning of numerous cell signalling pathways and the role of this structure in cancer initiation and progression is recently at the forefront of attention. Here, we investigated possible alterations in the occurrence of primary cilia and changes of associated signalling in ameloblastoma, which represents the most common odontogenic tumour.

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Carcinomas of the oral cavity and oropharynx belong among the ten most common malignancies in the human population. The prognosis of head and neck squamous cell carcinoma (HNSCC) is determined by the degree of invasiveness of the primary tumor and by the extent of metastatic spread into regional and distant lymph nodes. Moreover, the level of the perineural invasion itself associates with tumor localization, invasion's extent, and the presence of nodal metastases.

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Aim: To assess the role of orthoptics in referring patients with orbital floor blowout fracture (OFBF) for conservative or surgical treatment and based on the results, to propose a scoring system for such decision making.

Methods: A retrospective analysis of 69 patients with OFBF was performed (35 treated conservatively, 34 surgically). The role of orthoptics in referring to surgery or conservative treatment was retrospectively evaluated, the factors with the highest significance for decision making were identified, and a scoring system proposed using Logistic regression.

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In patients with orbital floor blowout fracture (OFBF), accurate diagnosis of ocular motility disorder is important for decisions about conservative or surgical therapy. However, the accuracy of the traditional test for detecting binocular diplopia/ocular motility disorder using a moving pencil or finger (hereinafter, "finger test") has been generally accepted as correct and has not been subject to scrutiny so far. Hence, its accuracy relative to full orthoptic examination is unknown.

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Background: Chronic wounds and their problematic healing is a widely discussed topic in all branches of medicine. In recent years, vacuum therapy appears to be a very successful non-invasive method supporting the healing of these wounds. The aim of this paper is to demonstrate the possibility of utilizing a vacuum system in the orofacial area where other conservative and surgical procedures have failed.

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Purpose: We evaluated the efficiency and toxicity of stereotactic hypofractionated boost in combination with conventionally fractionated radiotherapy in the treatment of advanced floor of the mouth cancer.

Methods: Thirty-seven patients with advanced stage of the floor of the mouth cancer, histologically confirmed squamous cell carcinoma (p16 negative) ineligible for surgical treatment, were indicated for radiochemotherapy or hyperfractionated accelerated radiotherapy (HART). The radiotherapy protocol combined external beam radiotherapy (EBRT) and a stereotactic hypofractionated boost to the primary tumor.

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Introduction: In patients with squamous cell carcinoma of the orofacial area, the presence of cervical metastases represents a single most significant prognostic factor. This fact underlines the importance of thorough examination of the cervical lymph nodes for potential tumor involvement. To verify this, the most common investigative methods are physical examination (PE), sonography (US) and computed tomography (CT), which have also been used to assess the stage of the disease in the patients in our research.

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During evolution, there has been a trend to reduce both the number of teeth and the location where they are found within the oral cavity. In mammals, the formation of teeth is restricted to a horseshoe band of odontogenic tissue, creating a single dental arch on the top and bottom of the jaw. Additional teeth and structures containing dental tissue, such as odontogenic tumors or cysts, can appear as pathologies.

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BACKGROUND Indication of oral appliances for the treatment of an obstructive sleep apnea (OSA) includes both patients with primary snoring and mild OSA, as well as patients with moderate to severe OSA who refuse other treatment or in whom such treatment failed. The aim of this study was to verify the effectiveness of current OSA treatment by objective measurements, and to assess by means of a questionnaire patients' satisfaction with oral appliances manufactured in our laboratory. MATERIAL AND METHODS The study enrolled 58 adult patients (40 men, 18 women) with mean age of 50.

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The temporomandibular joint (TMJ) is a condylar synovial joint that, together with the masticatory muscles, controls mandibular movement during mastication. The rabbit is often used as a model species for studying the mechanisms of TMJ diseases, and in regenerative research. However, there are significant differences between rabbit and human TMJs that should be taken into account before using this model for experimental research.

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Background: Buccal flexible films in the form of solid, thin, mucoadhesive patches can be used as dressings separating aphthous lesions from the environment of the oral cavity, which can in turn shorten the treatment period and reduce the pain perception.

Methods: The clinical study was performed on 36 volunteers suffering from aphthous lesions. The first group was treated using standard means-by application of an oral gel containing cholin salicylate (Mundisal) on the aphthous lesion.

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Frizzled 6 (FZD6) belongs to a family of proteins that serve as receptors in the WNT signaling pathway. FZD6 plays an important role in the establishment of planar cell polarity in many embryonic processes such as convergent extension during gastrulation, neural tube closure, or hair patterning. Based on its role during hair development, we hypothesized that FZD6 may have similar expression pattern and function in the dental lamina, which is also a distinct epithelial protrusion growing characteristically angled into the mesenchyme.

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Chameleon teeth develop as individual structures at a distance from the developing jaw bone during the pre-hatching period and also partially during the post-hatching period. However, in the adult, all teeth are fused together and tightly attached to the jaw bone by mineralized attachment tissue to form one functional unit. Tooth to bone as well as tooth to tooth attachments are so firm that if injury to the oral cavity occurs, several neighbouring teeth and pieces of jaw can be broken off.

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Objectives: Tooth agenesis is one of the most common developmental anomalies in humans. Genetic and environmental factors may be of etiological importance in this condition. Among genes involved in tooth morphogenesis, mutations in PAX9, MSX1, AXIN2, WNT10a, and EDA genes have been associated with tooth agenesis.

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Infectious stomatitis represents the most common oral cavity ailments. Current therapy is insufficiently effective because of the short residence time of topical liquid or semisolid medical formulations. An innovative application form based on bioadhesive polymers featuring prolonged residence time on the oral mucosa may be a solution to this challenge.

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Due to its similarity to humans, the pig has proven to be a suitable biomodel for both research purposes and for training medical professionals, particularly in surgical specializations. For example, new implant materials have been tested on pig jaws and pigs have also been used in the development of new surgical techniques. For optimizing the effectiveness of such research or training, detailed data on the anatomy of their particular features are needed.

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Clay minerals have been proposed as very useful materials for modulating drug delivery. These are the commonly used materials in pharmaceutical production both as inorganic carriers or active agents. We focused on the development of suitable long-acting material for local treatment of oral infection where clay minerals act as inorganic drug carriers.

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Mucoadhesive films represent the most developed medical form of buccal application. Despite the intense focus on buccal film-based systems, there are no standardized methods for their evaluation, which limits the possibility of comparison of obtained data and evaluation of the significance of influence of formulation and process variables on properties of resulting films. The used principal component analysis, together with a partial least squares regression provided a unique insight into the effects of in vitro parameters of mucoadhesive buccal films on their in vivo properties and into interdependencies among the studied variables.

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