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Biomedical subjects

J Betka

Publications and source records attributed to J Betka.

At least 19 recordsLinked to original sources
PubMed2006

Early detection of cancer: ideas for a debate.

Even if the overall number of cancer is increasing, the mortality has started to decrease in the Western World. The role of early detection in this decrease is a matter of debate. To assess its impact on mortality it is important to distinguish between diagnosis of cancer in symptomatic patients, and early detection in asymptomatic individuals who may self-refer or who may be offered ad hoc or systematic screening. The policies for early detection and screening vary greatly between European countries, despite many similarities in their cancer burden, and this partly reflects the uncertainties surrounding asymptomatic testing for cancer. A Task Force of European expert, held in Azzate (VA), Italy, established to address these issues, acknowledged the need for more research in the field of individual risk assessment since general statistics are more and more perceived as inadequate to design personal early detection plans. The group also recognised that combinations of early detection and screening will enforce the effectiveness of new treatments in curbing mortality curves, although policies will vary with different cancers.

Breast Neoplasms↗
PubMed2006

[Sentinel lymph node biopsy in oral and oropharyngeal carcinomas].

BACKGROUND: The aim of our study was to assess feasibility and accuracy of sentinel lymph node biopsy in patients with head and neck squamous cell carcinoma with clinically N0 neck. METHODS AND RESULTS: The sentinel lymph node was localised preoperatively by lymphoscintigraphy and intraoperatively by hand-held gamma probe after peritumoral injection of a Tc99m-labeled colloidal human serum albumin. The histology of the sentinel lymph node was compared with the histology of the nodes of the elective neck dissection performed in all patients. 27 patients with oral and oropharyngeal carcinomas accessible to injection in local anaesthesia were enrolled into a prospective trial between July 1993 and December 2005. The sentinel lymph node was localised by preoperative lymphoscintigraphy in 26 of 27 patients. Sentinel lymph node was identified perioperatively by hand-held gamma probe in all 28 necks of 27 patients. Occult metastases were found in 4 sentinel lymph nodes in 4 cases. In one case (3.6 %) the result of sentinel lymph node biopsy was false negative. The sentinel lymph node biopsy correctly predicted the positivity and negativity of the neck in 27 of 28 cases (96.4 %). CONCLUSIONS: Sentinel lymph node biopsy in patients with oral and oropharyngeal carcinomas is feasible and seems to accurately predict the status of the regional lymph nodes.

Adult↗
PubMed2006

Magnetic resonance imaging of the rat brain after epileptic seizures--preliminary results.

The magnetic resonance imaging (MRI) of the rat brain after the epilepsy seizures has been performed. As a first step, the model of the kainic acid (KA) induced seizures has been conducted to examine the possibilities of magnetic resonance imaging system kept in disposition. Seven Wistar albino rats, weighing about 300 g, were used in this study. We administered six of them with intraperitoneal injection of 10 mg/kg of KA. The control animal received corresponding volume of the saline. Every animal was examined under systemic anaesthesia induced by an intraperitoneal injection of thiopental sodium approximately 15 minutes before scanning. Diffusion-weighted imaging (DWI) has been used to acquire the coronary scans of the rat brain. The progress of hyper intense signal at the cerebral cortex and amygdale has been observed. Marked asymmetry of the signal intensity between hemispheres has been discovered. Subsequently the experimental model of audiogenic epilepsy will be conducted.

Animals↗
PubMed2005

Long-lasting changes in the density of nitrergic neurons following kainic acid administration and chronic hypoxia.

Using histochemical analysis (NADPH-diaphorase) we have investigated the influence of intraperitoneal administration of kainic acid (KA), hypoxia and combination of both these factors on neurons of the hippocampus and on the primary auditory cortex (PAC) in male rats of the Wistar strain. Kainic acid was administered to 18-day-old animals, which were exposed to long-lasting repeated hypoxia from the 2nd till the 17th day of age in a hypobaric chamber (for 8 hours a day). At the age of 1 year, the animals were transcardially perfused with 4 % paraformaldehyde under deep thiopental anesthesia. Cryostate sections were stained to identify NADPH-diaphorase positive neurons that were then quantified in CA1 and CA3 areas of the hippocampus, in the dentate gyrus and in the PAC. Both, hypoxia and KA lowered the number of NADPH-diaphorase positive neurons in the hilus, dorsal and ventral blades of the dentate gyrus, CA1 and CA3 areas of the hippocampus. On the contrary, KA given to the hypoxic animals increased the number of NADPH-diaphorase positive neurons in the dorsal blade of the dentate gyrus and PAC.

Animals↗
PubMed2005

HPV and other risk factors of oral cavity/oropharyngeal cancer in the Czech Republic.

OBJECTIVE: An association between high-risk human papillomavirus (HR HPV) infection and a risk of development of a subgroup of head and neck cancers has been proposed recently. The main risk factors of oral and oropharyngal cancer observed in our population are smoking and alcohol consumption. The incidence of oral/oropharyngeal tumours in the Czech Republic is relatively high and there are no data available about the prevalence of HPV DNA presence in these tumours. MATERIALS AND METHODS: Eighty patients with a primary oropharyngeal cancer were enrolled. The presence of HPV DNA has been evaluated by polymerase chain reaction in 68 cases from which the tumour tissue and demographical and clinical data were available. The typing of HPV was performed by nucleotide DNA sequencing. RESULTS: The HPV DNA was detected in 51.5% of samples tested. Among the HPV DNA positive tumours, 80% contained HPV16. In the analysed group there were 54 men and 14 women. The prevalence of HPV DNA was lower in oral (25%) than in oropharyngeal (57%) tumours, and higher in never smokers (100%) and never drinkers (68.8%). HPV DNA presence was not related to gender, age, number of lifetime sexual partners or practice of oral-genital sex, size of tumour or presence of regional metastases. CONCLUSIONS: The difference in the prevalence of HPV DNA positive tumours between cases of oral cavity and oropharyngeal carcinoma exposed and not exposed to tobacco or alcohol support the theory that HPV DNA positive tumours form an aetiologically distinct subgroup of head and neck tumours.

Adult↗
PubMed2005

Epidermal growth factor receptor--its expression and copy numbers of EGFR gene in patients with head and neck squamous cell carcinomas.

Signaling pathways activated by epidermal growth factor receptor (EGFR) are pathogenetically involved in the development of head and neck squamous cell carcinomas (HNSCC). A monoclonal antibody against the EGFR protein blocking the receptor activity (cetuximab - Erbitux - C225) is now available for therapeutic applications. The mechanisms of EGFR protein overexpression are poorly understood. Regulatory pathways, EGFR gene structural changes or its amplification may be involved. The aim of the study was to evaluate expression of the EGFR protein in patients with HNSCC, to identify EGFR gene copy numbers, and to find out whether the protein overexpression is associated with the EGFR gene amplification. In the case of a pathogenetical link of the EGFR gene amplification and the protein overexpression it would be useful to employ both diagnostic approaches to identify patients eligible for cetuximab therapy. We investigated 33 patients with HNSCC. The expression of EGFR protein was evaluated by immunohistochemistry, copy numbers of EGFR gene and the numbers of chromosome 7 centromeric signals were investigated by fluorescence in situ hybridization on interphasic nuclei (I-FISH). Histological sections from formalin fixed and paraffin embedded tissues were used. We observed three types of EGFR protein expression (homogeneous 3+ membrane positivity in 13 patients; membrane positivity varying from 1+ to 3+ in 12 patients; a strong membrane positivity at the periphery of the tumor cell clusters in 5 patients). In two cases the results were difficult to interpret. In one case single tumor cells only were positive. Numerical changes of chromosome 7 were present in 23 patients. We found the EGFR gene amplification in seven patients. The tumor cells with amplification of the EGFR gene were generally infrequent and were localized in small clusters, or they were randomly dispersed between the tumor cell population without the gene amplification. We did not find any correlation between the EGFR gene amplification and the EGFR protein overexpression. Thus, amplification of the EGFR gene is not pathogenetically involved in the EGFR protein overexpression. From the diagnostic aspect a standardized immunohistochemical assessment of the EGFR protein expression appears sufficient for detection of the EGFR status. Criteria for cetuximab treatment in patients with HNSCC may differ from those already used for patients with colorectal carcinomas and should take different patterns of the EGFR protein overexpression into consideration.

Adult↗
PubMed2005

Detection of new diagnostic markers in pathology by focus on growth-regulatory endogenous lectins. The case study of galectin-7 in squamous epithelia.

Lectins represent one of pivotal regulators of the cell proliferation The potential of galectin-7 as a new prognostic marker was studied in normal and transformed squamous epithelia of both ectodermal (epidermis, cornea vs. trichoepithelioma, basal and squamous cell carcinoma) and endodermal (vocal fold epithelium vs. carcinoma) origin. Studies on the cultured cells were also performed. Expression of galectin-7 seems to be connected to the process of stratification, no matter of origin of epithelium. Its expression is significantly reduced in malignant cells, thus galectin-7 might be a differentiation marker of epithelial malignancies.

Biomarkers, Tumor↗
PubMed2004

Serum levels of IGF-I, HGF, TGFbeta1, bFGF and VEGF in thyroid gland tumors.

IGF-I, HGF, TGFbeta1, bFGF and VEGF are involved in the pathogenesis of thyroid gland tumors and their growth. We decided to find whether changes in the production of these cytokines by thyroid tumor cells are reflected by changes of their peripheral blood. Using ELISA kits, we measured the concentrations of growth factors in the peripheral blood serum in 28 patients with thyroid gland tumors (14 adenomas, 14 papillary carcinomas) and compared these concentrations with those in healthy people. We found significantly lower serum levels of IGF-I in patients with thyroid adenoma compared to the healthy population. Serum levels of HGF and bFGF were significantly higher in patients with thyroid adenoma and papillary carcinoma compared with those in healthy subjects. Serum concentrations of TGFbeta1 and VEGF were not significantly different in any groups of investigated subjects. Changes in the production of these cytokines by thyroid gland tumor cells are reflected in their peripheral blood levels, but these levels also depend on a number of other physiological and pathological processes in the organism. However, significant differences of HGF and bFGF serum levels can be explained by their very high production by thyroid tumor cells and by their strong effect on the follicular and endothelial cell proliferation.

Adenoma↗
PubMed2004

Our surgical experience with large vestibular schwannomas.

Our aim is to remove large vestibular schwannomas (VS) radically with minimal morbidity. Usually, these tumours cannot not be treated by irradiation. In the years 1997-2003, 69 VS were operated in the Department of Otorhinolaryngology, Head and Neck Surgery of the First Medical Faculty in Prague, Czech Republic. Prevailing majority of these tumours were of the 4th grade (House classification), compressing the brainstem. Six patients in the group suffered from neurofibromatosis 2, in five cases the patients were indicated for neurosurgery due to rapid tumour growth after previous irradiation. All tumours were radically removed using a retromastoid osteoplastic and translab approach with an intraoperative nerve monitoring. Good function of the facial nerve was achieved in 90%. The nerve had to be resutured in 4 cases with consequent satisfactory results, cross anatomosis was not performed. Hearing function was preserved in 8% of patients only. In 6 patients with neurofibromatosis 2, the auditory brainstem implant (ABI) was used to preserve hearing. This study demonstrates that a radical removal of large vestibular schwannomas is possible using a minimally invasive surgical technique and peroperative nerve monitoring with a good impact on quality of life. Auditory brainstem implants bring a new chance of hearing after tumour removal in patients with NF2.

Adult↗
PubMed2004

Changes in the number of nitrergic neurons following kainic acid administration and repeated long-term hypoxia.

Using histochemical analysis (NADPH-diaphorase) we have been investigating the influence of intraperitoneal administration of kainic acid (KA), hypoxia and combination of both these factors on neurons of the hippocampus and on the primary auditory cortex (PAC) in male rats of the Wistar strain. Kainic acid was administered to 18-day-old animals, which were exposed to long-lasting repeated hypoxia from the 2nd till the 17th day of age in a hypobaric chamber (for 8 h a day). At the age of 22 or 90 days, the animals were transcardially perfused with 4 % paraformaldehyde under deep thiopental anesthesia. Cryostate sections were stained to identify NADPH-diaphorase positive neurons that were then quantified in the hippocampus, in the dentate gyrus and in the PAC. In 22-day-old animals both hypoxia and KA increased the number of NADPH-diaphorase positive neurons in the hilus, CA1, CA3 areas of the hippocampus and in the PAC. On the contrary, KA given to hypoxic animals lowered the number of NADPH-diaphorase positive neurons in the dentate gyrus. In 90-day-old animals, hypoxia and KA given to both normoxic and hypoxic animals lowered the number of NADPH-diaphorase positive neurons in some areas of the central nervous system.

Adaptation, Physiological↗
PubMed2004

[Treatment of benign stenoses of the large airways at the Faculty Hospital Praha-Motol during 1998-2003].

The authors present diagnostic and therapeutical results in the group of 80 patients with benign stenoses of large airways, who were hospitalized at the TRN ward (Department of TB and respiratory disorders) of the Faculty hospital Motol in Prague between the years 1998-2003. 62 patients sufferred from stenoses in cosequence of their tracheal intubation or tracheostomy. In 18 cases the stenoses resulted from other disorders or pathological condidtions (Wegener's granulomatosis, status post lung transplantation, etc.) 38 patients were sent for surgery. Up until the date of the assessment (September 2003), 8 of them had had a relaps of the condiditon. 6 operated subjects had their restenosis corected using bronchological methods, 2 subjects had to undergo reoperation, which is 5.2% of the total number of the operated subjects. The remaining 42 patients were treated using the interventional bronchological methods (electrocauther, laser, stents) which proved curative in 35 patients, i.e 44% of the whole group. In 7 inoperable patients the above methods failed, 6 of them having a permanent tracheostomy and one female-patient exited 2 days after an incomplete recanalization. In the subgroup of 18 patients with other than postintubation stenoses, stent operations were the most frequent (12 times), 4 patients were cured using other methods of interventional bronchology, and resection of the stenosis was indicated in two cases. Up until the date of the assessment, 65 subjects had survived and 15 exited. 5 of them died 3-14 months (median of 4 months) following the surgical procedure of other disorders than of the respiratory airways stenoses. 10 unoperated patients, with a single exception, also died due to other causes than the tracheobroncheal lesions (the survival rate median was 9 months). Following the initial freeing of the airways, the authors call for considering a surgical therapeutical option in each case. Provided the surgical approach was contraindicated, the interventional bronchological methods would replace it appropriately.

Adolescent↗
PubMed2003

[Use of the auditory brainstem neuroprosthesis in the Czech Republic].

BACKGROUND: Auditory brainstem implant (ABI) is an electroprosthetic device enabling sound sensations in deaf persons with a bilateral lesion of auditory nerves. Stimulation of auditory nuclei in the floor of the IVth ventricle is realized by an electrode array introduced during surgery in the lateral recess of the IVth ventricle. METHODS AND RESULTS: The main indication group for ABI is represented by patients with neurofibromatosis 2 (NF2) suffering from bilateral vestibular schwannomas. During surgery aimed at tumour removal, auditory nerve function and integrity are almost always destroyed, therefore, an ABI can be introduced as an one stage procedure. Implantees use the device mainly as the aid in lipreading, only very rarely they can comprehend speech without visual cues. Auditory brainstem implant programme has been introduced in the Czech Republic in the year 1999. It was the very first ABI surgery in the Central Europe. Since that time, 5 patients had received the auditory brainstem implant, from which the first four use the device for a longer time. CONCLUSIONS: The last operated patient has not been activated yet. It may be said, that ABI represents a benefit to all our patients, in one implanted this benefit is significant, since he can understand speech without lipreading, the other implantees use the device as an aid in lipreading. In one female patient, the device benefit is severely limited by a motoric handicap after partial cerebellar resection during surgery. Nevertheless, she uses the implant on a daily basis, but contact with her is limited and difficult.

Adult↗
PubMed2001

[Rhinitis--still a real problem].

Paper brings about findings on rhinitis--definition, classification and clinical picture. New discoveries concern mycotica infection and some methods of investigation. Differential diagnosis of rhinosinusitis includes several diseases. Author presents some possibilities of therapy of rhinitis and includes relations between upper and lower respiratory airways.

Common Cold↗
PubMed2001

Subjective functional results 1 year after surgery and postoperative radiation for oropharyngeal carcinoma.

This study was conducted to find out what factors most influenced functional results and patient satisfaction at 1 year after treatment in a homogeneous group of patients who had undergone surgery and postoperative radiotherapy for the treatment of oropharyngeal carcinoma. Further aims were to find out the relation between the overall and specific disease-related results and to compare the two questionnaires used. The study group consisted of 102 patients, 23 women and 79 men, with an age range of 41-77 years (mean 45.7 years). Two questionnaires were used for evaluation. The University of Washington head and neck quality of life questionnaire (UW-QOL) includes information about nine disease-specific domains and three questions on general quality of life. The second questionnaire used was the performance status scale for head and neck cancer patients (PSS), containing information about three disease-specific domains. Functional results were influenced by the size of tumor and by the surgical method used. Results worsened with increasing T stage. The best results were found after pharyngotomy without mandibulotomy, worse results, following temporary mandibulotomy with osteosynthesis, and the poorest results were found in the group of patients who had undergone composite resection. Neither age and sex of the patients nor the course of healing influenced the functional results. All results were significantly correlated to one another. The general parameters were also closely related to specific domains. An important correlation was found between the parameters in the two questionnaires.

Activities of Daily Living↗
PubMed2001

Expression of galectin-3-reactive ligands in squamous cancer and normal epithelial cells as a marker of differentiation.

The definition of biological markers for oropharynx and larynx cancer is essential to predict their clinical behavior. Since cellular glycans play an important role in biological information transfer, we have employed an endogenous lectin, galectin-3, to examine in primary squamous carcinomas, lymph node metastases, and physiological squamous epithelia whether glycans recognized by this lectin are altered in relation to the state of differentiation. The expression of galectin-3 was concomitantly evaluated by immunohistochemistry using the A1D6 monoclonal antibody. In addition, other antibodies were used for the detection of cytokeratins and desmosomal proteins (desmoplakin-1 and desmoglein). The results show the expression of galectin-3-reactive ligands in moderately/highly differentiated carcinomas only in areas exhibiting a high level of keratinization. Except for one patient out of 14, metastatic cells in lymph nodes expressed no accessible binding sites for galectin-3. No galectin-3-reactivity was detected in the basal cell layer of all studied normal epithelia (which contains the proliferating cells). The suprabasal layers were positive in epidermis and epithelium of tongue and cornea and negative in epithelium of palatine tonsil. The tumor cells expressed galectin-3 with an intensity positively correlated with tumor differentiation. The position of galectin-3-reactive sites colocalized with the two tested desmosomal proteins. However, presence of these proteins was also detected in areas of tumor and suprabasal layers of tonsil epithelium where no binding reactivity for galectin-3 was found. The present study showed that expression of galectin-3-reactive glycoligands is differentiation-dependent in normal as well as malignant squamous cells. Colocalization of galectin-3-reactive sites with desmosomal proteins (desmoplakin-1 and desmoglein) suggests an association of the galectin-3 ligand(s) with the cell surface, pointing to a potential participation of galectin-3 in mediation of intercellular contacts in these tumor types.

Antigens, Differentiation↗
PubMed2001

Heterotopy of thyroid tissue--a modified therapeutical approach.

OBJECTIVES: The authors describe the classification of heterotopic thyroid tissue. A survey of more than 600 literature cases is provided. Different therapy approaches for these anomalies are discussed. Data from seven subsequent cases have been added to the existing literature data. The authors present an alternative approach to the therapy of heterotopic thyroid tissue. MATERIALS AND METHODS: The records of seven patients treated for a heterotopy of the thyroid tissue as the Department of ENT and Head and Neck Surgery of First Medical school of the Charles University of Prague since 1.1.1991 to 1.1.2001 have been analyzed. RESULTS: The first group: No surgery. This approach was used for children. In these patients the heterotopic thyroid tissue is the only thyroid tissue they have, but its function is not damaged and there are no mechanical symptoms (no airway obstruction and dysphagia). TSH substitution-suppression therapy is necessary for this group. Cooperation and follow up by the endocrinology, otolaryngology and pediatric departments is necessary. At a later age these patients can be treated as in the second group. The second group: Surgery. All patients in this group had heterotopic thyroid tissue. The total removal of thyroid tissue has been preferred. Carcinomatous change or the development of mechanical syndrome, dysphagia or airway obstruction is possible. Total removal is the best surgical approach. Various surgical methods are described in the literature (CO2 laser, intraoral, mandibulotomy, middle hyotomy etc.). These patients are treated as after total thyroidectomy and substitution therapy with synthetic thyroid hormones is necessary. The authors describe and add seven cases to the literature data. The authors describe radical removal of aberrant and accessory tissue [corrected].

Adolescent↗