Fatigue behavior of resin-modified monolithic CAD-CAM RNC crowns and endocrowns.

OBJECTIVE: To evaluate the influence of different types of modifications with resin on fatigue resistance and failure behavior of CAD-CAM resin nano ceramic (RNC) restorations for maxillary first premolars. METHODS: Sixty standardized resin composite root dies received CAD-CAM RNC endocrowns (n=30) and crowns (n=30) (Lava Ultimate, 3M Espe). Restorations were divided into six groups: full anatomic endocrowns (group A) and crowns (group D), buccal resin veneered endocrowns (group B) and crowns (group E) and buccal resin veneered endocrowns (group C) and crowns (group F) with a central groove resin filling. A nano-hybrid resin composite was used to veneer the restorations (Filtek Supreme, 3M Espe). All specimens were first submitted to thermo-mechanical cyclic loading (1.7Hz, 49N, 600000 cycles, 1500 thermo-cycles) and then submitted to cyclic isometric stepwise loading (5Hz) until completion of 105000 cycles or failure after 5000 cycles at 200N, followed by 20000 cycles at 400N, 600N, 800N, 1000N and 1200N. In case of fracture, fragments were analyzed using SEM and modes of failure were determined. Results were statistically analyzed by Kaplan-Meier life survival analysis and log rank test (p=0.05). RESULTS: The differences in survival between groups were not statistically significant, except between groups D and F (p=0.039). Endocrowns fractured predominantly with a mesio-distal wedge-opening fracture (82%). Partial cusp fractures were observed above all in crowns (70%). Analysis of the fractured specimens revealed that the origin of the fracture was mainly at the occlusal contact points of the stepwise loading. SIGNIFICANCE: Veneering of CAD-CAM RNC restorations has no influence on their fatigue resistance except when monolithic crowns are modified on their occlusal central groove.

[Growth and detection of aerobic bacterial pathogens in BacT/Alert FA, BacT/Alert SA, Bactec Plus Aerobic/F and Bactec Standard Aerobic/F]. / Rust a detekce aerobních bakteriálních patogenu v lahvickách BacT/Alert FA, BacT/Alert SA, Bactec Plus Aerobic/F a Bactec Standard Aerobic/F.

The article compares the ability of detection and detection times (TTD) of aerobic bacteria in the BacT/Alert FA, BacT/Alert SA, Bactec Plus Aerobic/F and Bactec Standard Aerobic/F bottles. Compared bottles were inoculated at the same time with the identical suspension of bacterial strain. All bottles detected bacterial pathogens even in the case of very low number of inoculated bacteria. The differences of TTD were detected between the bottles of compared hemocultivation systems. Bactec Plus Aerobic/F system is faster in the detection of the members of family Enterobacteriaceae at 1-3 hours, BacT/Aert FA system is faster in the detection of coagulase-negative staphylococci. Most difference was detected at Pseudomanas stutzeri, where the detection in BacT/Alert FA bottles was at 15 hours faster in opposite of Bactec Plus Aerobic/F bottles. In the bottles without sorbent Staphylococcus aureus and Streptococcus sanqui were detected faster in the system Bactec Standard Aerobic/F. The bottles BacT/Alert SA detected faster skin corynebacteria. Detected differences have not a practical importance for the blood stream infection diagnostics.

Capillary electrophoresis of peptides and proteins with plug of Pluronic gel.

Electromigration capillary methods are promising techniques in proteomics and they are still under research. We used a partial filling approach, i.e. a combination of gel and non-gel separation mechanisms in a single dimension. We tried using an interesting gel, Pluronic F 127, which can be considered as a surfactant capable of self-association both with isotropic and anisotropic gels. The Pluronic was inserted inside the capillary as a plug at the start of the capillary, and it provided separation at the first time. Separation by this gel was achieved according to molecular weight and/or hydrophobicity. The applicability of this method was demonstrated in the separation of real samples-peptides arising from collagen after CNBr or collagenase cleavage and albumin after trypsin cleavage (peptide mapping). Some peptides and proteins were selectively retained by the Pluronic gel. These interactions with the gel did not depended on their molecular weight alone, but they probably depend on a combination of both principles. It was confirmed that capillary electrophoresis with Pluronic plug can give us another new separation option, complementary to free solution capillary electrophoresis. The CE method presented here, consisting of a partial filling approach with combine gel and non-gel separation mechanisms seemed to be a promising method for the separation of complex mixtures of peptides.

Separation of poly(amidoamine) (PAMAM) dendrimer generations by dynamic coating capillary electrophoresis.

The separation of compounds possessing amino groups (peptides, proteins, polyamino compounds) by capillary zone electrophoresis suffers from the interaction (sticking) of these solutes with the capillary wall. This sticking can result in the absence or incomplete separation of compounds or even in their retention in the capillary. Polyamidoamine (PAMAM) dendrimers are a class of spherical polymers with primary amino groups at the surface. These compounds can be separated reasonably well at acidic pH but not at neutral pH. A new method based on the dynamic coating of the capillary was developed for the separation of these compounds at pH 7.4. The method comprises separation in a fused-silica capillary (57 cm total length, 50 cm to the detector, ID 75 microm) and a background electrolyte consisting of a Tris-phosphate buffer (50 mmol/L, pH 7.4) and 0.05% (w/v) polyethyleneimine. This system is suitable for the separation of 7 generations of dendrimers (generations 0-6). The dynamic coating agent (polyethyleneimine) also improves the separation at acid pH.

[Quantitative microbiological diagnostic method of intravascular catheters infection using the BacT/Alert SA bottles]. / Metoda kvantitativní mikrobiologické diagnostiky infekce cévních katetru vyuzívající lahvicky BacT/Alert SA.

OBJECTIVE: The study describes a method of quantitatively examining vascular catheters with the aid of hemocultural devices BacT/Alert. MATERIAL AND METHODS: The amount of bacteria present on the surface of the vascular catheters was determined based on the time to detection (TTD) in hemocultural vials inoculated with bacterial suspension stirred off the catheter surface. RESULTS: A total number of 348 vascular catheters was examined with this new method. Positive cultures were detected in 26 (7.5 %) catheters. Accordance to the results of microbiological catheter examination with clinical condition of the patient was found in 93.1 %. False positivity occurred in 1.1 % (4) and false negativity in 5.7 % (20) of cases. On the basis of clinical symptoms 42 cases of catheter sepsis were diagnosed out of which 22 (52.4 %) positive microbiological quantitative examinations of vascular catheters were established. The most frequent pathogen was coagulase negative staphylococci. CONCLUSIONS: The new method, when compared with present methods, is simpler, faster and able to detect the most frequent agent of catheter infection.

HLA-DQ polymorphisms modify the risk of thyroid autoimmunity in children with type 1 diabetes mellitus.

OBJECTIVE: Type 1 diabetes mellitus (DM1) is frequently accompanied by thyroid autoimmunity (TAI). The aims of the present study were to estimate the prevalence of TAI and to determine the contribution of HLA-DQA1 and -DQB1 polymorphisms to TAI susceptibility among children with DM1. PATIENTS AND METLHODS: Screening for TAI was performed in 285 children with DM1 by measuring autoantibodies against thyroid peroxidase (anti-TPO) and thyroglobulin (anti-Tg). HLA-DQA1 and -DQB1 were genotyped using PCR-SSP. RESULTS: Repeated positivity of anti-TPO and/or anti-Tg was found in 45/285 children with DM1 (15.8%). The prevalence was significantly higher in girls than in boys (26.7% vs 6.7%; p<10(-5)). The HLA-DQB1*0302 allele conferred susceptibility to TAI in children with DM1 (OR 2.7, 95% CI 1.1-6.4), while the DQB1*05 alleles acted protectively (OR 0.2, CI 95% 0.08-0.7). CONCLUSIONS: HLA-DQ polymorphisms significantly modify the risk of TAI in children with DM1.

[Prediction of insulin-dependent diabetes mellitus in children of first-degree relatives of diabetic patients]. / Predikce inzulin dependentního diabetes mellitus u detských prvostupnových príbuzných diabetických pacientu.

BACKGROUND: Individuals at risk for insulin dependent diabetes mellitus (IDDM) can be identified using a combination of genetic, immunological and metabolic markers. Our study was aimed at prediction of IDDM in a cohort of children having a first-degree relative with IDDM. METHODS AND RESULTS: In the period of three years, we investigated 208 non-diabetic children and adolescents, aged 10.0 +/- 5.3 (mean +/- SD), mostly siblings of diabetic children. The genetic risk was determined by the HLA-DQB1, -DQA1 genotyping and subtyping of the DRB1*04 alleles carried on the DQB1*0302 haplotypes. Insulitis was detected using a combination of autoantibody tests against three molecular-defined antigens (insulin, GAD65, IA-2). Prevalence of insulitis (defined as confirmed positivity of at least one autoantibody) was 9/208 (4.3%). In children carrying the IDDM highest-risk genotype (HLA-DQB1*0201-DQA1*05/DQB1*0302-DQA1*03), insulitis was almost 10 times more frequent (5/24, 21%) than in children with other genotypes (4/184, 2.2%, P = 0.003). In all subjects with insulitis, the first phase insulin response (FPIR) was determined by the intravenous glucose tolerance test. Three of the nine children had decreased FPIR, of whom two were later diagnosed with IDDM. None of the remaining children developed IDDM. CONCLUSIONS: We present the first IDDM prediction study in the Czech population, emphasising the utility of genetic risk investigation in the prediction scheme.

HLA class II genetic association of type 1 diabetes mellitus in Czech children.

To examine human leukocyte antigen (HLA) class II association of type 1 diabetes mellitus (DM) in Czech children, we performed a case-control study of 261 patients diagnosed before the age of 15 and 289 non-diabetic control children. Complete HLA-DQA1, DQB1 genotyping and DRB1*04 subtyping were carried out by polymerase chain reactions with sequence-specific primers. The effect of the DRB1*04 subtypes was studied in DRB1*04 alleles carried on DQB1*0302-DQA1*03 haplotypes. The risk was statistically evaluated by testing 2 x 2 tables, considering corrected p-values < 0.05 significant. The DQB1*0302 (odds ratio, OR = 9.0), DQB1*0201 (OR = 3.4) and DQA1*03 (OR = 7.5) alleles were significantly associated with diabetes risk, while the DQB1*0602 (OR = 0.02), DQB1*0301 (OR = 0.08), DQB1*0503 (OR = 0.13), DQB1*0603 (OR = 0.20), DQA1*01 (OR = 0.28) and DQA1*02 (OR = 0.26) alleles were significantly protective. Of the DQA1-DQB1 genotypes, we point out the extremely high risk of OR = 116 conferred by HLA-DQA1*05-DQB1*0201/DQA1*03-DQB1*0302. Among DRB1*04 subtypes, DRB1*0403 was significantly protective (OR = 0.05, CI 95% 0.01-0.45). Since none of the remaining DRB1*04 subtypes was associated with type 1 DM, our study may present another piece of evidence that the DRB1*0401 and DRB1*0404 alleles do not modify type 1 diabetes risk generally in European populations.

[Autoantibodies to GAD65, IA2 and insulin in Czech children with type 1 diabetes]. / Autoprotilátky proti GAD65, IA2 a inzulinu u ceských detí pri manifestaci diabetu 1. typu.

BACKGROUND: Autoimmune insulitis leading to insulin dependent diabetes mellitus (IDDM, Type 1 Diabetes) is accompanied by autoantibodies as its invaluable markers. The aim of the study was to determine the frequency of autoantibodies against GAD65, IA2 and insulin in Czech diabetic children at the disease onset. METHODS AND RESULTS: Sera of 105 newly diagnosed children with IDDM drawn within 24 hours after the first insulin dose were investigated for anti-GAD65, anti-IA2 and insulin autoantibodies (IAA) using RIA methods. The cut-off normal levels were determined as the 99th percentile of 105 non-diabetic children. At given 99% specificity, the sensitivity was 71% for anti-GAD65, 73% for anti-IA2, and 46% for IAA. 29% diabetic children were positive for all three autoantibodies, 25% had anti-GAD65 and anti-IA2 (IAA negative), 5.7% anti-GAD65 and IAA (anti-IA2 negative), 7.6% anti-IA2 and IAA (anti-GAD65 negative). As the only positive autoantibody, anti-GAD65 was found in 12%, anti-IA2 in 11%, and IAA in 3.8% children. In 5.7% children, none of the investigated autoantibodies was positive. Diabetic children diagnosed before the age of 5 years had significantly higher prevalence of IAA than the older ones. CONCLUSIONS: We have determined normal levels in healthy children, and prevalence at childhood IDDM onset of autoantibodies against three main molecular-defined autoantigens.