Publications by authors named "Plzak J"

Heterogeneous cancers that lack strong driver mutations with high penetrance, such as head and neck squamous cell carcinoma (HNSCC), present unique challenges to understanding their aetiology due to the complex interactions between genetics and environmental factors. The interplay between lifestyle factors (such as poor oral hygiene, smoking, or alcohol consumption), the oral and gut microbiome, and host genetics appears particularly important in the context of HNSCC. The complex interplay between the gut microbiota and cancer treatment outcomes has also received increasing attention in recent years.

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Induction of autophagy represents an effective survival strategy for nutrient-deprived or stressed cancer cells. Autophagy contributes to the modulation of communication within the tumor microenvironment. Here, we conducted a study of the metabolic and signaling implications associated with autophagy induced by glutamine (Gln) and serum starvation and PI3K/mTOR inhibitor and autophagy inducer NVP-BEZ235 (BEZ) in the head and neck squamous cell carcinoma (HNSCC) cell line FaDu.

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Objective: Resection of the vestibular schwannoma causes acute peripheral vestibular loss. The process of central compensation starts immediately afterward. The rehabilitation goal is to support this process and restore the quality of life.

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Objective: One of the possible risks of sinonasal malignancy is its possible spread in the orbit. However, there is no clear consensus among the different departments as to whether it is necessary to exenterate the orbit in limited tumorous infiltration of periorbital fat. The purpose of the study was to demonstrate that periorbital infiltration and periorbital fat invasion without involvement of deeper orbital tissues are not the indication of orbital exenteration.

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Introduction: Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors, which are mostly benign in nature. Amongst all genes, Succinate Dehydrogenase Subunit D () is the most commonly mutated in familial HNPGLs. In about 30% of HNPGLs, germline mutations in can also occur in the absence of positive family history, thus giving rise to "occult familial" cases.

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Objectives: The objective of this study is to address issues faced by doctors working in the COVID-19 units during the second phase of COVID-19 in the Czech Republic, when the country registered the highest per capita rate of new COVID-19 cases in the world.

Methods: A prospective study was designed using Google online questionnaire. Inclusion criteria were doctors from medical and surgical specialties working in COVID-19 units.

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Purpose: Early detection of mucosal neoplastic lesions is crucial for a patient's prognosis. This has led to the development of effective optical endoscopic diagnostic methods such as narrow band imaging (NBI) and autofluorescence (AFI). Independent of each other, both of these methods were proven useful in the detection of mucosal neoplasias.

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Purpose: Pleomorphic adenoma (PA), the most common benign tumour of the parotid gland, requires accurate preoperative diagnosis owing to its capacity for malignant transformation. The aim of this study was to evaluate our experience with ultrasound-guided fine-needle aspiration biopsy (FNAB) in the diagnostic algorithm for patients with PA and to assess clinical outcomes for those with different surgical approaches.

Material And Methods: We carried out a retrospective analysis of patients treated for parotid gland mass between 2010 and 2016.

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Background And Aim: Minimally invasive endoscopic techniques are the treatment of choice for Zenker's diverticulum (ZD). Our objective was to evaluate the results and efficacy of endoscopic and open approaches, to determine whether postoperative C-reactive protein (CRP) serum levels can be used as a marker to exclude the presence of esophageal leakage, and to identify risk factors for development of postoperative leakage and complications.

Materials And Methods: Patients who underwent transcervical myotomy and diverticulotomy (TMD) or endoscopic cricopharyngeal myotomy (ECM) with CO laser for ZD in years 2008-2021 at our department were included in this retrospective study.

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Article Synopsis
  • Salivary gland carcinomas (SGC) are rare cancers with limited treatments, and anti-CD47 antibodies may offer a new therapy by enhancing tumor cell clearance, depending on CD47 expression in the tumor environment.
  • A study of 43 SGC patients examined CD47 expression in both tumor cells and immune cells infiltrating the tumors, revealing important insights about anti-CD47 therapy's potential effectiveness.
  • Findings indicated that immune cells expressing CD47 outnumbered tumor cells in certain cases, particularly in low-grade tumors, suggesting a protective mechanism for immune cells at the tumor’s edge, preventing their destruction while allowing older immune cells to be cleared from the center.
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Head and neck squamous cell carcinomas (HNSCC) belong among severe and highly complex malignant diseases showing a high level of heterogeneity and consequently also a variance in therapeutic response, regardless of clinical stage. Our study implies that the progression of HNSCC may be supported by cancer-associated fibroblasts (CAFs) in the tumour microenvironment (TME) and the heterogeneity of this disease may lie in the level of cooperation between CAFs and epithelial cancer cells, as communication between CAFs and epithelial cancer cells seems to be a key factor for the sustained growth of the tumour mass. In this study, we investigated how CAFs derived from tumours of different mRNA subtypes influence the proliferation of cancer cells and their metabolic and biomechanical reprogramming.

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We carried out a survey in the Czech Republic between January and February 2021 to evaluate the impact of COVID-19 on doctors working in the COVID-19 unit. A rise in 250,000 cases were seen in the Czech Republic during the time of the survey. The indirect impact of the disease on doctors working in COVID-19 units and strategies to control the situation in the Czech Republic were evaluated here.

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Purpose: Warthin tumour (WT) management options comprise surgery or follow-up. The purpose of this study was to asses our experience with the follow-up strategy in selected patients with an ultrasound-guided fine-needle aspiration biopsy (FNAB) showing WT.

Methods: We performed a retrospective analysis of patients diagnosed with WT using FNAB between 1.

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Introduction: The facial nerve surgery belongs to the basic procedures during lateral skull base approaches. Its damage has serious medical and psychological consequences, and therefore mastery of reconstruction and correction techniques should belong to the repertoire of skull base surgeons. The goal of this study was to demonstrate usefulness of electromyographic follow-up in facial nerve reconstruction.

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Salivary gland carcinomas (SGCs) are extremely morphologically heterogeneous, and treatment options for this disease are limited. Immunotherapy with immune checkpoint inhibitors (ICIs) represents a revolutionary treatment approach. However, SGCs remain largely resistant to this therapy.

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Introduction: The incidence of thyroid disorders has been rising worldwide. Unlike the incidence, mortality associated with malignant thyroid cancer shows only a modest increase. Between 1979 and 2009, mortality in Czech women increased from 1.

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Purpose: SARS-CoV-2 vaccines are a key step in fighting the pandemic. Nevertheless, their rapid development did not allow for testing among specific population subgroups such as pregnant and breastfeeding women, or elaborating specific guidelines for healthcare personnel working in high infection risk specialties, such as otolaryngology (ORL). This clinical consensus statement (CCS) aims to offer guidance for SARS-CoV-2 vaccination to this high-risk population based on the best evidence available.

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Cancer-associated fibroblasts (CAFs) are one of the most abundant and critical components of the tumor stroma. CAFs can impact many important steps of cancerogenesis and may also influence treatment resistance. Some of these effects need the direct contact of CAFs and cancer cells, while some involve paracrine signals.

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Objectives: The COVID-19 disease has an incredible impact on both hospital-based and private practices in the field of otorhinolaryngology and head and neck surgery. Practical issues faced by both types of practices have not been well addressed in most studies. A national survey was conducted in April 2020 to identify the challenges faced by otorhinolaryngologists practicing in the Czech Republic.

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The treatment options for patients with advanced salivary gland cancers (SGCs) are limited. Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment. However, the response to ICI immunotherapy is largely driven by the immune cell signatures within the tumor tissue and the para-tumoral tissue compartments.

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Background: The SARS-COV-2 virus has more than just an infectious role to play in the society. The rapid spread has also led to significant personal, professional, financial and economic recession globally. Health care professionals are getting seriously compromised due to these issues.

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The SARS-CoV-2 virus causing the COVID-19 disease created considerable complications and disruptions due to it's pandemic spread. The nature of the disease left certain clinical specialties more vulnerable than others, causing serious problems with organization of care of patients. Most studies concentrated on protocols and strategies to control the situation and reduce further spread amongst medical fields.

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Background: Low-grade fibromyxoid sarcoma (LGFMS) is a rare malignant tumor. Moreover, only 3 cases of LGFMS originating from the nasal cavity and/or paranasal sinuses have been published so far.

Methods: Two patients with histologically confirmed LGFMS of the maxillary sinus were primarily treated by open and endoscopic surgery.

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