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Biomedical subjects

O Krejsa

Publications and source records attributed to O Krejsa.

17 recordsLinked to original sources
PubMed2000

Th1 and Th2 cytokine profile in patients with early onset periodontitis and their healthy siblings.

Early onset periodontitis (EOP) is a chronic inflammatory periodontal disease with a strong genetic link affecting individuals aged 17 to 25. In the familial studies we tested the hypothesis about the role of Th1 and Th2 cytokines in the pathogenesis of EOP disease. The study involved 6 individuals with EOP disease and their 6 siblings with healthy periodontium. Actinobacillus actinomycetemcomitans (A. a), a bacterium typical for EOP, was detected in all people studied. Th1 and Th2 cytokine production was measured after in vitro stimulation. Peripheral blood mononuclear cells (PBMC) were isolated and cultivated for 24 h and 7 days with PWM, A. a. or Escherichia coli. The levels of IL-4, IFN-gamma, IgA, IgG and IgM were measured by ELISA methods. After in vitro stimulation of PBMC, a significantly higher production of IL-4 and significantly lower production of IFN-gamma were found in the group of patients compared with their healthy siblings. The increased level of IL-4 in patients was in good agreement with an increased level of IgM after stimulation of lymphocytes with E. coli. These results support Seymour's hypothesis according to which patients with progressive disease primarily activate Th2 lymphocytes while non-susceptible individuals activate Th1 lymphocytes.

Adolescent↗
PubMed1998

Noncontact Er:YAG laser ablation: clinical evaluation.

OBJECTIVE: The aim of this study is to evaluate the quality of laser ablation in comparison with the classical drilling preparation. METHODS: For the experiment, the Er:YAG laser drilling machine was used. The system had a laser head, water cooler, and power supply with automatic control. Spot size of 300-350 microns was used for the preparation. Repetition rate of 1-4 Hz, and pulse energies of 100-400 mJ with water spray were chosen. Cavity shape in comparison with classical drill, time of preparation, and influence of cavity shape on filling materials retention in accordance with the U.S. Public Health Service System were used. The evaluation criteria for noncontact Er:YAG ablation were done. RESULTS: The cavity shape is irregular, but spot surface has larger area and microretentive appearance. Caries of enamel and dentin were treated with a noncontact preparation. It was possible to remove the old insufficient fillings, except for amalgam or metal alloys. The average number of pulses was 111.22 (SE 67.57). Vibrations of microexplosions during preparation were felt by patients on 14 cavities; however, nobody felt unpleasant pain. The qualities of filling materials in laser cavities were very stable; however, cavo surface margin discoloration of 82-86% of Alfa rating could be a problem. Changes of the color and anatomic form of the tooth were observed in 4-8%. CONCLUSIONS: In comparison with the classical treatment, it could be said that the retention and quality of filling materials is the same or very similar.

Adult↗
PubMed1997

Dentin and pulp response to Erbium:YAG laser ablation: a preliminary evaluation of human teeth.

OBJECTIVE: We determined the real effect of Erbium:YAG laser ablation on human teeth in vivo. SUMMARY BACKGROUND DATA: We advocated the idea that overheating of teeth, specially pulp damage can be avoided if correct laser parameters are used. METHODS: We evaluated human premolars scheduled for extraction during orthodontic treatment. Before tooth extraction, an oval cavity preparation was made with a pulsed Er:YAG laser. After extraction, the teeth were decalcified for 6 weeks. Routine staining with haematoxylin and eosin was performed on longitudinal section. One hundred seventy-two sections were prepared and examined in a light microscope. RESULTS: Under Er:YAG laser application, reduction of the dentin layer was observed. Dentinal tubules had a radial course up to the surface. No cracks or structural injury were observed. Inflammatory reaction in the pulp was not found. The vascularity of the pulp was normal. The odontoblasts were of the usual spindle-like or star-like cell shape. The cementum and epithelial attachment were healthy. No changes of structure or indications of inflammation were observed. CONCLUSIONS: The results of this in vivo experiment on human teeth confirm safety of Er:YAG laser ablation of enamel and dentin under the conditions described.

Adolescent↗
PubMed1996

Expression of the LFA-1 beta molecule on peripheral blood leukocytes of patients with early-onset periodontitis: effects of dental plaque microbes.

The effect of dental plaque bacteria on LFA-1 beta expression on peripheral blood leukocytes was studied in 20 patients with early-onset periodontitis and in 10 healthy controls. Stimulation of PMN with selected dental plaque bacteria which play a role in the pathogeny of periodontitis significantly increased the expression of LFA-1 beta in the group of patients as compared with the controls.

Actinomyces viscosus↗
PubMed1990

[Partial results of an investigation of the state of dentition of the Czechoslovak population with regard to targets of WHO for the year 2000].

In 1987 a nation-wide survey of the state of dentition of Czechoslovak population in age groups of 2-65 years and above was made. The paper presents the results in the age category of 5-6 years, 12 years, 18 years, 35-44 and 65 year and more, with regard to criteria defined for WHO targets for the year 2000. Data for the CSSR, SSR and CSSR are presented separately.

Adolescent↗
PubMed1989

[Comparison of Czechoslovak and foreign toothpastes].

The authors made a nation-wide investigation focused on the consumption of foreign toothpastes and their evaluation, as compared with locally produced ones. They also assessed the properties of selected foreign toothpastes according to the Czechoslovak norm by laboratory tests. The investigation related that foreign toothpastes are purchased by one quarter of the subjects where enquiries were made. The main reason for selection of a foreign toothpaste was better taste and a better sensation of fragrance. People appreciate also the attractivity packing and adequate information on the properties and composition of the toothpaste. As compared with local toothpastes, the better taste of foreign ones is emphasized. Laboratory tests of the properties of foreign tooth pastes, as compared with local revealed that from the physico-chemical and microbiological aspect local toothpastes compare favourably with foreign ones. However, the organoleptic properties, packing and information are not comparable.

Czechoslovakia↗
PubMed1989

[Czechoslovak toothpaste--present choice, consumption, quality].

The authors made a nation-wide survey focused on the choice, appreciation of different properties of toothpastes and the popularity of different brands. They also evaluated the quality of some toothpastes according to Czechoslovak standards. The results revealed that the attitude of the public as regards toothpastes is correct. The great majority of subjects consider fluorine and therapeutic substances an important part of toothpastes. The majority of subjects are satisfied with the supply, one third of the people complain that some types are in short supply. More than half the subjects ask for toothpastes with texts providing information. The majority of toothpastes met the demand defined by the Czechoslovak standards. Some shortcomings were revealed during organoleptic evaluation and in the technology of production. The authors discuss the small consumption of toothpastes which must be increased by the health educational activities of dental surgeons but also by increased attention of manufactures and the network of shops to the technology, distribution and propagation of toothpastes.

Consumer Behavior↗