The optimal setting of complex fractionated atrial electrogram software in substrate ablation for atrial fibrillation

BACKGROUND

Complex fractionated atrial electrogram (CFAE)-targeted catheter ablation (CFAE ablation) requires a high rate of atrial fibrillation (AF) termination to provide good outcomes. We determined the optimal settings of CFAE software.

METHODS

In our 430 consecutive patients, AF was terminated in 97 (234/242) and 79% (149/188) of patients with paroxysmal and persistent AF, respectively, by CFAE ablation combined with (31%) or without (69%) pulmonary vein isolation, occasionally with nifekalant infusion. We analyzed 109 consecutive patients who underwent CFAE ablation to determine the optimal settings for comparing subjective versus objective decisions by the CFAE software on CARTO3. We compared three settings: the default setting (0.05-0.15 mV, 50-120 ms) and two modified settings (#1: 0.05-0.30 mV, 40-70 ms, #2: 0.05-0.13 mV, 10-20 ms). We retrospectively analyzed 11,425 points during left atrial mapping before ablation and 10,306 points that were subjectively detected and ablated as CFAE points. An interval confidence level ≥6 denoted a site with CFAE.

RESULTS

With the default setting, the accuracy, sensitivity, specificity, positive productive value, and negative productive values were 67, 42, 77, 48, and 73%, respectively. With modified setting #1, the values were 78, 55, 87, 74, and 77%, respectively, versus 64, 82, 60, 53, and 91%, respectively, for modified setting #2.

CONCLUSION

These data suggest that setting #1 was generally superior to the default setting, whereas setting #2 was optimal for excluding areas not requiring ablation. The optimal CFAE software setting was a voltage of 0.05-0.30 mV and an interval parameter of 40-70 ms.

Variable alteration of regional tissue oxygen pressure in rat hippocampus by acute swimming exercise

One of the events in the brain is an increasing cerebral blood flow during exercise. The tissue oxygen level may be increased because blood flow correlates with tissue oxygen level. However, it is little known whether the tissue oxygen pressure in hippocampal region (Hip-pO2) will be affected by exercise.

AIMS

The aim of this study is to examine Hip-pO2 levels in the hippocampus and its changes during exercise.

MAIN METHODS

We applied improved Clark-type electrodes to measure Hip-pO2 level in the hippocampus of rats that were subjected to three groups, 2h swimming without weights (low intensity, n=6), 2h swimming with a 5 g weight (moderate intensity, n=6), and 2h swimming with a 10 g weight (high intensity, n=6).

KEY FINDINGS

Exercise affected the Hip-pO2 level, the responses varied with the exercise intensity and duration. Interestingly during and after the Low intensity swimming the Hip-pO2 level showed long lasting enhancement (10-20% above resting level). But the moderate and high intensity swimming increased Hip-pO2 level at the start of the swimming (50%, P<0.05 and slightly above resting level, respectively, at 10 min of 2h swimming) and then began to decrease (at 120 min and 10 min of 2h swimming, respectively), and suppressed the Hip-pO2 levels during post exercise resting period (2h) (85-95% of resting level, NS and 60-70% of resting level P<0.05, respectively).

SIGNIFICANCE

We propose that exercise-induced hippocampal hyper/hypo oxygen condition may participate in beneficial exercise effects on brain function.

Occlusal trauma accelerates attachment loss at the onset of experimental periodontitis in rats

BACKGROUND AND OBJECTIVE

Occlusal trauma is an important factor that influences the progression of periodontitis, but it is unclear whether occlusal trauma influences periodontal destruction at the onset of periodontitis. We established an experimental periodontitis model with both site-specific loss of attachment and alveolar bone resorption. The purpose of the present study was to investigate the effects of occlusal trauma on periodontal destruction, particularly loss of attachment, at the onset of experimental periodontitis.

MATERIAL AND METHODS

Sixty rats were used in the present study. Forty-eight rats immunized with lipopolysaccharide (LPS) intraperitoneally were divided into four groups. In the trauma (T) group, occlusal trauma was induced by placing an excessively high metal wire in the occlusal surface of the mandibular right first molar. In the inflammation (I) group, periodontal inflammation was induced by topical application of LPS into the palatal gingival sulcus of maxillary right first molars. In the trauma + inflammation (T+I) group, both trauma and periodontal inflammation were simultaneously induced. The PBS group was administered phosphate-buffered saline only. Another 12 nonimmunized rats (the n-(T+I) group) were treated as described for the T+I group. All rats were killed after 5 or 10 d, and their maxillary first molars with surrounding tissues were observed histopathologically. Loss of attachment and osteoclasts on the alveolar bone crest were investigated histopathologically. To detect immune complexes, immunohistological staining for C1qB was performed. Collagen fibers were also observed using the picrosirius red-polarization method.

RESULTS

There were significant increases in loss of attachment and in the number of osteoclasts in the T+I group compared with the other groups. Moreover, widespread distribution of immune complexes was observed in the T + I group, and collagen fibers oriented from the root surface to the alveolar bone crest had partially disappeared in the T, T+I and n-(T+I) groups.

CONCLUSION

When inflammation was combined with occlusal trauma, immune complexes were confirmed in more expanding areas than in the area of the I group without occlusal trauma, and loss of attachment at the onset of experimental periodontitis was increased. Damage of collagen fibers by occlusal trauma may elevate the permeability of the antigen through the tissue and result in expansion of the area of immune-complex formation and accelerating inflammatory reaction. The periodontal tissue destruction was thus greater in the T+I group than in the I group.

Assessment of the Plasma/Serum IgG Test to Screen for Periodontitis

Chronic periodontitis is a silent infectious disease prevalent worldwide and affects lifestyle-related diseases. Therefore, efficient screening of patients is essential for general health. This study was performed to evaluate prospectively the diagnostic utility of a blood IgG antibody titer test against periodontal pathogens. Oral examination was performed, and IgG titers against periodontal pathogens were measured by ELISA in 1,387 individuals. The cut-off value of the IgG titer was determined in receiver operating characteristic curve analysis, and changes in periodontal clinical parameters and IgG titers by periodontal treatment were evaluated. The relationships between IgG titers and severity of periodontitis were analyzed. The best cut-off value of IgG titer against Porphyromonas gingivalis for screening periodontitis was 1.682. Both clinical parameters and IgG titers decreased significantly under periodontal treatment. IgG titers of periodontitis patients were significantly higher than those of healthy controls, especially in those with sites of probing pocket depth over 4 mm. Multiplied cut-off values were useful to select patients with severe periodontitis. A blood IgG antibody titer test for Porphyromonas gingivalis is useful to screen hitherto chronic periodontitis patients (ClinicalTrials.gov number NCT01658475).

Enzastaurin has anti-tumour effects in lung cancers with overexpressed JAK pathway molecules

BACKGROUND

Enzastaurin, an oral serine-threonine kinase inhibitor, was initially developed as an ATP-competitive selective inhibitor against protein kinase Cβ. However, the mechanism by which enzastaurin contributes to tumourigenesis remains unclear.

METHODS

We analysed the anti-tumour effects of enzastaurin in 22 lung cancer cell lines to ascertain the potential for enzastaurin-based treatment of lung cancer. To identify molecules or signalling pathways associated with this sensitivity, we conducted a gene, receptor tyrosine kinases phosphorylation and microRNA expression profiling study on the same set of cell lines.

RESULTS

We identified eight genes by pathway analysis of molecules having gene-drug sensitivity correlation, and used them to build a support vector machine algorithm model by which sensitive cell lines were distinguished from resistant cell lines. Pathway analysis revealed that the JAK/STAT signalling pathway was one of the main ones involved in sensitivity to enzastaurin. Overexpression of JAK1 was observed in the sensitive cells by western blotting. Simultaneous administration of enzastaurin and JAK inhibitor inhibited enzastaurin-induced cell growth-inhibitory effect. Furthermore, lentiviral-mediated JAK1-overexpressing cells were more sensitive to enzastaurin than control cells.

CONCLUSION

Our results suggested that the JAK1 pathway may be used as a single predictive biomarker for enzastaurin treatment. The anti-tumour effect of enzastaurin should be evaluated in lung cancer with overexpressed JAK pathway molecules.

Peptidoglycan and lipopolysaccharide synergistically enhance bone resorption and osteoclastogenesis

BACKGROUND AND OBJECTIVE

Peptidoglycan (PGN) and lipopolysaccharide (LPS) are bacterial cell wall constituents that are able to induce bone resorption by stimulating Toll-like receptor (TLR) 2 and TLR4, respectively. The fragments of PGN also stimulate inflammatory responses via nucleotide-binding oligomerization domain (NOD) 1 and NOD2, although there are differences in the NOD-stimulatory activities between gram-positive and gram-negative PGNs. The TLR and NOD signaling pathways are known to engage in cross-talk to enhance the production of inflammatory cytokines. In the present study, we investigated the effects of gram-negative and gram-positive PGNs on bone resorption and osteoclastogenesis in the presence or absence of LPS.

MATERIAL AND METHODS

We injected Escherichia coli PGN or Staphylococcus aureus PGN with or without LPS into mouse gingiva, and histopathologically assessed alveolar bone resorption by tartrate-resistant acid phosphatase staining. We also stimulated osteoclast precursors from mouse bone marrow macrophages with these PGNs in vitro and assessed osteoclastogenesis. The cells were also stimulated with synthetic ligands for NOD1; γ-D-glutamyl-meso-DAP NOD2; muramyl dipeptide or TLR2; Pam(3) CSK(4) with or without LPS to analyse the signaling cross-talk.

RESULTS

S. aureus PGN, but not E. coli PGN, induced alveolar bone resorption, as did LPS. However, PGN from both sources significantly enhanced the bone resorption in the mice co-injected with LPS. Both types of PGNs induced osteoclastogenesis and accelerated osteoclastogenesis when the cells were co-stimulated with LPS in vitro. All synthetic ligands synergistically induced osteoclastogenesis by co-stimulation with LPS.

CONCLUSION

Gram-positive or gram-negative PGN worked synergistically with LPS to induce bone resorption and osteoclastogenesis, possibly by co-ordinating the effects of TLR2, NOD1, NOD2 and TLR4 signaling.