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Biomedical subjects

J Mazánek

Publications and source records attributed to J Mazánek.

At least 19 recordsLinked to original sources
PubMed2005

Changing of facial skeleton for treatment of obstructive sleep apnoea syndrome.

Obstructive sleep apnoea syndrome (OSAS) is a potentially life-threatening disorder. It is characterized by at least five episodes of apnoea or hypopnoea during sleep lasting for more than 10 seconds. Apnoea or hypopnoea are accompanied by respiratory efforts. Changes of the facial skeleton by mandibular or maxillo-mandibular advancement belong to surgical techniques which might affect moderate and severe OSAS. In the surgical procedure mandible alone or the upper and lower jaws are moved forward by at least 10 mm. Thus also muscles fixed to the facial skeleton and upper airway dilatators are moved forward. The discussion also mentions possible complications and limitations of this surgical technique.

Humans↗
PubMed2004

The examination of the temporomandibular joint on 1,5T magnetic resonance.

The most frequent intraarticular disorder of the temporomandibular joint (TMJ) represents the disorder of the functional relation between the articular disc and mandible condyle, i.e. dislocation of the articular disc. Magnetic resonance (MR) optimally visualizes the soft and hard articular tissues (articular disc, articular socket and condyle of the mandible) and its surroundings. The aim of the study was to evaluate findings of MR investigation of the TMJ. We investigated billateraly 26 patients with TMJ disorders during the years 1996 and 2003. All patients were examined on 1,5 T MR. Joints were studied in T1 and T2 weighted images with closed mouth and during mouth opening in dynamic study. MR verified dysfunction was observed in 48 investigated TMJ (92,3 %), hydrops of the joint was observed in 3 joints (5,8 %), arthrosis of the condylar head in 4 patients (7,6 %). Only four TMJ had normal MR finding (7,6 %). MR represents the best method for studying clinically affected joints, for the evaluation of the morphological state of TMJ and the analysis of the dynamic process during mouth opening. Method is also useful for revealing of a disorder in clinically silent joints. T2 weighted image in TSE mode brought best imaging of the joint. The fat saturation sequence was advantageous mainly in liquid storage (hydrops of the joint, edema in the adjacent bone). The dimensions of the articular cleft and bone components of the joint were well-visualized in T1 weighted images.

Adolescent↗
PubMed2000

Low-level laser therapy after molar extraction.

OBJECTIVE: The aim of the study was to evaluate effect of the different frequencies of low-level laser radiation (diode 670 nm and Helium-Neon 632.8 nm) on the healing process after human molar extractions. Frequencies of 5 Hz, 292 Hz, and 9,000 Hz were used in experiments. Monitoring of secretory IgA and albumin level in saliva and changes in bone density were used as objective markers of biostimulatory effect. SUMMARY BACKGROUND DATA: From the literature, it is known that if the alveolus is irradiated after extraction along with the lingual and buccal bony wall, faster coagulation, less postoperative discomfort, and quicker healing can be expected. METHODS: Subjective evaluation of therapy was observed using a scale (from -, negative therapeutic effect, to ++++, excellent treatment effect). Changes of secretory immunoglobulin A (sIgA), albumin levels, and bone density were compared in a group of 150 patients (nonlaser therapy, 30 patients). RESULTS: Differences in levels of the saliva markers (sIgA and albumin) were found to be significant when comparing irradiated and nonirradiated groups, and in comparison with those groups irradiated by various modulatory frequencies. Significant differences were observed between the increase of sIgA res. albumin and subjective feelings during treatment. Bone density after extraction and 6 months after surgical treatment was examined using dental digital radiovisiography. No significant differences were detected between bone density in irradiated and nonirradiated groups, perhaps due to our therapy protocol. CONCLUSIONS: The low-level laser has no influence on the process of osseointegration. This effect was observed on fracture healing in rats using He-Ne laser radiation. We found no differences in the bone density when compared to the control group.

Adolescent↗
PubMed1995

[Solitary "traumatic" mandibular cyst].

A 34-year old man had an unusually localized cyst at the lower margin of mandibular body. It was sharply defined by X-rays. Microscopy showed necrotic masses with numerous cholesterol crystals and groups of lipophages which represented a solitary so called "traumatic" mandibular cyst. History of the case did not prove unequivocal relation to traumatic pathogenesis of the cyst.

Adult↗
PubMed1989

[Computer tomography and its use in orofacial oncology].

The authors communicate their experience with the application of CT in the diagnosis of neoplasms in orofacial region. The examinations were done with the head CT apparatus of 2nd generation. Indications for this examination are defined in the following areas: 1) retromaxillary, 2) paranasal sinuses, 3) orbits, 4) parotid glands, 5) cranial base, 6) malformation diseases, 7) mandibular joint, 8) lower region of the face and neck, 9) cervical nodes, 10) tumours extensive in volume. The authors present an analysis of results of 63 examinations in 57 patients with tumorous diseases.

Head and Neck Neoplasms↗
PubMed1986

Enzyme histochemistry of human melanomas and pigmented naevi with special reference to alpha-D-mannosidase activity.

A histochemical study of alpha-D-mannosidase revealed that normal human melanocytes (resting state, activated, lentigo simplex) exhibit either no or just detectable activity, as do melanocytes in the initial phase of lentigo maligna. Junctional, or occasionally zone A naevocytes displayed a very low enzyme activity. On the other hand, melanocytes in the initial stage of neoplastic transformation (dysplastic naevi, advanced stage of lentigo maligna) and also melanoma cells in disorders of low malignant potential (initial naevogenic melanoma, superficial spreading melanoma) displayed a high activity uniformly throughout the cell population. In the malignant forms (nodular melanoma, recurrences, metastases), the enzyme activity was remarkably heterogeneous, suggesting a breakdown of uniformity during malignant transformation. The significance of alpha-mannosidase activity induction in the course of melanocyte neoplastic transformation is not clear at present. The results of biochemical assays suggest that the lysosomal isoenzyme is mainly responsible. Other lysosomal enzymes, and dehydrogenases studied concomitantly, did not display any comparable phenomena of induction or similar behaviour. However, the results of a comparison of alpha-mannosidase with the melanocyte reference enzyme tyrosinase suggested activity patterns in the enzyme pair which may provide a better insight into the biochemical differentiation of human melanocytes in neoplastic disorders. The possible relationship of alpha-mannosidase to melanogenesis is also discussed.

Acid Phosphatase↗
PubMed1986

[Diagnostic considerations apropos of a case of keratoacanthoma in a child].

A seven year old child presented with a keratoacanthoma, sometimes defined as a primary idiopathic pseudoepitheliomatous hyperplasia, on the mandibular alveolar process. The lesion showed typical proliferation of a tumoral nature, clinical manifestations and microscopic findings being those of a spindle cell carcinoma and easily mistaken for the latter. The solitary oral form of the tumor is a rare benign affection that does not recur after extirpation. A literature review identified only four similar cases.

Alveolar Process↗
PubMed1980

[Classification of epithelial odontogenic tumors].

A retrospective series of 31 purely epithelial odontogenic tumours consisted of 21 ameloblastomas, 2 adenomatoid odontogenic tumours, 2 calcifying epithelial odontogenic tumours, and 6 calcifying odontogenic cysts. Modern histological classification gives an accurate picture of some of the structural and biological differences between the above types of tumour. In spite of the, their common basis does result in some of the common features so that the precise classification of the specific tumour may pose problems or give rise to terminological disputes. For practical work it will do in the group of epithelial odontogenic tumours to insist strictly on the basic condition of the absence of either proliferating mesenchyma or hard dental tissues. This requirement naturally leads to the placing of ameloblastic odontoma outside the field of purely epithelial odontongenic tumours. Judging the biological nature of epithelial odontogenic tumours according to their structure is not reliable, a fact brought out by comparisons of ameloblastoma and adenomatoid odontogenic tumours. Rather one could rely on the nature of tumour growth. An evidently carcindependent classification pattern. Suspicion of a higher degree of malignity can be expressed by description.

Adult↗
PubMed1980

[Classification of epitheliomesenchymal odontogenic tumors].

In a group of 34 epitheliomesenchymal odontogenic tumours no difficulties were encountered in recognizing the seven-member group of ameloblastic fibroma (with ameloblastic odontoma and dentinoma included as variants) as distinct from group of odontomas (ameloblastic o. - 2x, complex o. - 20x, combined o. - 5x) The definition is rather a general one with the distinction of variants only sometimes possible. No ameloblastic fibrosarcoma or ameloblastic odontosarcoma were seen in the group; therefore, the question should be asked whether it is really expedient to keep independent places in the classification for so rare tumours.

Humans↗
PubMed1980

[Classification of mesenchymal odontogenic tumors].

A retrospective series of 9 purely mesenchymal odontogenic tumours was found to consist of 3 odontogenic fibromas, 2 myxomas, and 4 cementomas including one true benign cementoblastoma and two cementifying fibromas. One as seen to contain a conspicuously blood supplied proliferating fibrous component giving the tumour the appearance of a malignant process though no relapse was noted after the jaw resection. Periapical cement dysplasia was seen in only one case of the group; there was no case of gigantiform cementoma. The problems of mutual differential diagnosis and distinction from osteogenic tumours are subject to discussion.

Humans↗