Biofilm Spreading by the Adhesin-Dependent Gliding Motility of Flavobacterium johnsoniae: 2. Role of Filamentous Extracellular Network and Cell-to-Cell Connections at the Biofilm Surface

Flavobacterium johnsoniae forms a thin spreading colony on nutrient-poor agar using gliding motility. As reported in the first paper, WT cells in the colony were sparsely embedded in self-produced extracellular polymeric matrix (EPM), while sprB cells were densely packed in immature biofilm with less matrix. The colony surface is critical for antibiotic resistance and cell survival. We have now developed the Grid Stamp-Peel method whereby the colony surface is attached to a TEM grid for negative-staining microscopy. The images showed that the top of the spreading convex WT colonies was covered by EPM with few interspersed cells. Cells exposed near the colony edge made head-to-tail and/or side-to-side contact and sometimes connected via thin filaments. Nonspreading sprB and gldG and gldK colonies had a more uniform upper surface covered by different EPMs including vesicles and filaments. The EPM of sprB, gldG, and WT colonies contained filaments ~2 nm and ~5 nm in diameter; gldK colonies did not include the latter. Every cell near the edge of WT colonies had one or two dark spots, while cells inside WT colonies and cells in SprB-, GldG-, or GldK-deficient colonies did not. Together, our results suggest that the colony surface structure depends on the capability to expand biofilm.

Biofilm Spreading by the Adhesin-Dependent Gliding Motility of Flavobacterium johnsoniae. 1. Internal Structure of the Biofilm

The Gram-negative bacterium Flavobacterium johnsoniae employs gliding motility to move rapidly over solid surfaces. Gliding involves the movement of the adhesin SprB along the cell surface. F. johnsoniae spreads on nutrient-poor 1% agar-PY2, forming a thin film-like colony. We used electron microscopy and time-lapse fluorescence microscopy to investigate the structure of colonies formed by wild-type (WT) F. johnsoniae and by the sprB mutant (ΔsprB). In both cases, the bacteria were buried in the extracellular polymeric matrix (EPM) covering the top of the colony. In the spreading WT colonies, the EPM included a thick fiber framework and vesicles, revealing the formation of a biofilm, which is probably required for the spreading movement. Specific paths that were followed by bacterial clusters were observed at the leading edge of colonies, and abundant vesicle secretion and subsequent matrix formation were suggested. EPM-free channels were formed in upward biofilm protrusions, probably for cell migration. In the nonspreading ΔsprB colonies, cells were tightly packed in layers and the intercellular space was occupied by less matrix, indicating immature biofilm. This result suggests that SprB is not necessary for biofilm formation. We conclude that F. johnsoniae cells use gliding motility to spread and maturate biofilms.

Colony spreading of the gliding bacterium Flavobacterium johnsoniae in the absence of the motility adhesin SprB

Colony spreading of Flavobacterium johnsoniae is shown to include gliding motility using the cell surface adhesin SprB, and is drastically affected by agar and glucose concentrations. Wild-type (WT) and ΔsprB mutant cells formed nonspreading colonies on soft agar, but spreading dendritic colonies on soft agar containing glucose. In the presence of glucose, an initial cell growth-dependent phase was followed by a secondary SprB-independent, gliding motility-dependent phase. The branching pattern of a ΔsprB colony was less complex than the pattern formed by the WT. Mesoscopic and microstructural information was obtained by atmospheric scanning electron microscopy (ASEM) and transmission EM, respectively. In the growth-dependent phase of WT colonies, dendritic tips spread rapidly by the movement of individual cells. In the following SprB-independent phase, leading tips were extended outwards by the movement of dynamic windmill-like rolling centers, and the lipoproteins were expressed more abundantly. Dark spots in WT cells during the growth-dependent spreading phase were not observed in the SprB-independent phase. Various mutations showed that the lipoproteins and the motility machinery were necessary for SprB-independent spreading. Overall, SprB-independent colony spreading is influenced by the lipoproteins, some of which are involved in the gliding machinery, and medium conditions, which together determine the nutrient-seeking behavior.

Comparison of neointimal coverage between biodegradable-polymer everolimus-eluting stent and durable-polymer everolimus-eluting stent using angioscopy for the patients with acute coronary syndrome

Background

New-generation biodegradable-polymer platinum chromium everolimus-eluting stent (BP-PtCr-EES) is available, which has different polymer and alloy compare to more established stent design, a durable-polymer cobalt-chromium everolimus-eluting stent (DP-CoCr-EES).

Purpose

To compare neointimal coverage (NIC) between BP-PtCr-EES and DP-CoCr-EES by using coronary angioscopy (CAS).

Methods

A total of 36 patients (44 stents) with BP-PtCr-EES or DP-CoCr-EES who underwent CAS at 1 year after stenting were investigated. We compared angioscopic findings assessed by angioscopy between BP-PtCr-EES (n=18) and DP-CoCr-EES (n=26). NIC grade and yellow plaque grade (YPG) was adopted from earlier reports from grade 0 to 3. We determined maximum (max-) and minimum (min-) NIC grade and heterogeneity score (HGS = max NIC grade minus min NIC grade). We also assessed YPG and the presence of thrombus (TH).

Results

Six lesions (33.3%) in BP-PtCr-EES group and 7 (26.9%) lesions in DP-CoCr-EES group were culprit lesions of acute coronary syndrome, which did not statistically differ between the two groups (p=0.74). And there were no significant differences in stent diameter (BP-PtCr-EES: 2.97±0.39 mm vs DP-CoCr-EES: 3.14±0.45 mm, p=0.22) and length (BP-PtCr-EES: 26.9±7.9 mm vs DP-CoCr-EES: 28.4±8.0 mm, p=0.54). In terms of CAS findings, BP-PtCr-EES group has better neointimal coverage than DP-CoCr-EES group (max NIC grade: 2.6±0.7 vs 2.0±0.9, p=0.01. min NIC grade: 1.1±0.8 vs 0.5±0.5, p<0.01), but HGS was almost same (1.6±0.7 vs 1.5±0.9, p=0.70). YPG of BP-PtCr-EES group showed significantly lower than DP-CoCr-EES group (1.0±1.0 vs 1.7±1.0, p=0.02). The rate of TH was significantly lower in BP-PtCr-EES group than DP-CoCr-EES group (25%, n=6, vs 75%, n=18, p=0.03). There were no clinical events such as stent thrombosis or restenosis during the observation period in both stent groups.

Conclusion

Superior neointimal coverage and less YPG or TH were observed by CAS in the BP-PtCr-EES group at 1 year after stenting. Clinical significance was still unknown because of no clinical events in both groups. Prospective and large populations studies may be required.

Funding Acknowledgement

Type of funding source: None

P6439Clinical outcomes of acute coronary syndrome with intact-fibrous cap plaque at the culprit lesions in diabetic and non-diabetic patients

Background

Previous studies revealed that the morphological substrates of the culprit lesion assessed by optical coherence tomography (OCT) in acute coronary syndrome (ACS), which includes ruptured plaque (RP) and intact fibrous cap (IFC) plaque, are associated with subsequent clinical outcomes. Nevertheless, the impact of culprit morphology on clinical outcomes has not been evaluated in patients with diabetes mellitus (DM), which is one of the major determinants of clinical prognosis.

Purpose

We sought to investigate the association of the culprit lesion morphology with clinical outcomes in patients with DM and those without DM.

Methods

We retrospectively investigated a total of 508 patients with acute myocardial infarction (AMI) experiencing their first episode of ACS in whom OCT-guided, primary percutaneous coronary intervention (PCI) was performed and a culprit lesion was observed by OCT with sufficient image quality. Patients were divided into two groups according to the culprit lesion morphology into patients with RP (RP group) and those without RP (IFC group). The rate of major adverse cardiac events (MACE) including death, myocardial infarction, target or non-target lesion revascularizations were compared between RP and IFC groups in patients with DM (DM) and those without DM (non-DM), separately.

Results

MACE was captured in 80 patients during the median follow-up of 505 (IQR 274–1300) days. In non-DM, RP group showed significantly worse MACE-free rate than in IFC group (Figure), In DM, there was no significant difference between RP and IFC groups (Figure).

Figure 1

Conclusion

Culprit lesion morphology assessed by OCT was not associated with clinical outcomes in DM patients unlike non-DM patients. Distinct strategy for secondary prevention may be required for DM patients.

6111Optical coherence tomography derived predictors of restenosis after non-stenting coronary intervention with drug-coated balloon

Background

One of the limitations of metallic stents including contemporary drug eluting stents lies in the permanent existence of metallic materials within the coronary arteries, which may lead to neoatherosclerosis and a long-term use of dual antiplatelet therapy. Some reports have recently suggested the efficacy and safety of non-stent strategy with drug-coated balloon (DCB) angioplasty in combination with debulking devices for de novo lesions. However, little is known about the potential risk of restenosis after percutaneous coronary intervention (PCI) with DCB.

Purpose

We sought to assess the predictive factors of restenosis by optical coherence tomography (OCT) after PCI with DCB instead of metallic stents.

Methods

We retrospectively investigated 49 de novo lesions in 38 patients treated by DCB without stent implantation in whom OCT was performed immediately after PCI and follow-up angiography was performed at median of 5.6 (3.7–6.9) months. OCT findings after PCI and the incidence of restenosis at follow-up angiography were evaluated. By means of OCT images, medial coronary dissection was defined as a dissection which reached the medial layer of the vessel, and major dissection was defined as a dissection with more than 60 degrees of the circumference of the vessel or more than 3mm in length. Restenosis was defined as more than 50% diameter stenosis evaluated by Quantitative Coronary Angiography.

Results

Restenosis was observed in 13 of 49 lesions (27%). In univariate logistic regression analysis, major dissection and medial dissection at the final OCT were associated with restenosis (Odds ratio [OR] 10.0; 95% confidence interval [CI] 2.5–52.6; p<0.01 and OR 5.8; 95% CI 1.5–25.1; p=0.01, respectively). Lesion preparation prior to DCB were performed with rotational atherectomy (n=9), orbital atherectomy (n=2), directional atherectomy (n=4), excimer laser angioplasty (n=17), scoring balloon angioplasty (n=13), or balloon angioplasty (n=4). OCT-defined major dissection remained a significant predictor for restenosis independent of debulking devices used for the preparation (OR 8.1; 95% CI 1.2–70.2; p=0.03).

Conclusions

Major dissection was associated with restenosis after non-stenting PCI with DCB. Stent implantation should be considered in cases of OCT-defined major dissection.

Acknowledgement/Funding

None

P5622Clinical significance of late-acquired malapposition observed by serial optical coherence tomography after second-generation drug eluting stents

Background

Previous studies have demonstrated that the presence of late-acquired stent malapposition after stent implantation may be a risk of late and very late stent thrombosis and myocardial infarction, which is however still controversial.

Purpose

We sought to investigate the incidence and prognosis of late acquired stent malapposion after second-generation drug eluting stents (2G-DES) implantation.

Methods

A total of 199 lesions in 139 patients who underwent optical coherence tomography (OCT) at both immediately after implantation (Baseline) and 6–12 months after 2G-DES implantation (follow-up) were investigated. We excluded lesions with stent failure before follow-up examination. We evaluated presence or absence of malapposed strut at 1mm interval of OCT images and stents with one or more cross-sections with >30% malapposed strut was defined as stents with malapposition (MP), otherwise well-apposed (WA). We divided the lesions into 4 groups according to the presence of malapposition at baseline and follow-up; WA and WA, persistent well-apposed; MP and WA, resoloved malapposition; WA and MP, late acquired malapposition (LAMP); and MP and MP, persistent malapposition. We compared the target lesion failure (TLF) rate after follow-up examination among 4 groups with Kaplan–Meier analysis.

Results

Median follow-up period was 469 (IQR 71–1416) days. follow-up OCT examination was performed at median 9 months (IQR 7.6–10.5). There were no significant differences in patient's and procedural characteristics among the 4 groups. TLF rate in LAMP group was 12.0% and Kaplan–Meier analysis showed no significant differences among the 4 groups in TLF rate.

TLF-free suvival curves (Kaplan-Meier)

Conclusion

LAMP was observed by OCT at 6–12 months in 12.0% of lesions after 2G-DES implantation, which was not associated with TLF at 5 years.

Calcium phosphate mineralization in bone tissues directly observed in aqueous liquid by atmospheric SEM (ASEM) without staining: microfluidics crystallization chamber and immuno-EM

The malformation and disordered remodeling of bones induce various diseases, including osteoporosis. We have developed atmospheric SEM (ASEM) to directly observe aldehyde-fixed bone tissue immersed in radical scavenger buffer without thin sectioning. The short procedure realized the observation of bone mineralization surrounded by many cells and matrices in natural aqueous buffer, decreasing the risk of changes. In osteoblast primary cultures, mineralization was visible without staining. Correlative energy dispersive X-ray spectrometry indicated the formation of calcium phosphate mineral. Fixed bone was sectioned, and the section surface was inspected by ASEM. Mineralized trabeculae of talus spongy bone were directly visible. Associated large and small cells were revealed by phosphotungstic acid staining, suggesting remodeling by bone-absorbing osteoclasts and bone-rebuilding osteoblasts. In tibia, cortical bone layer including dense grains, was bordered by many cells with protrusions. Tissue immuno-EM performed in solution for the first time and anti-cathepsin-K antibody, successfully identified osteoclasts in femur spongy bone. A microfluidics chamber fabricated on the silicon nitride film window of an ASEM dish allowed mineralization to be monitored in vitro; calcium phosphate crystals as small as 50 nm were imaged. ASEM is expected to be widely applied to study bio-mineralization and bone-remodeling, and to help diagnose bone-related diseases.

Extending coherence time of macro-scale diamond magnetometer by dynamical decoupling with coplanar waveguide resonator

Ultimate sensitivity for quantum magnetometry using nitrogen-vacancy (NV) centers in a diamond is limited by a number of NV centers and coherence time. Microwave irradiation with a high and homogeneous power density for a large detection volume is necessary to achieve a highly sensitive magnetometer. Here, we demonstrate a microwave resonator to enhance the power density of the microwave field and an optical system with a detection volume of 1.4 × 10^-3 mm³. The strong microwave field enables us to achieve 48 ns Rabi oscillation which is sufficiently faster than the phase relaxation time of NV centers. This system combined with a decoupling pulse sequence, XY16, extends the spin coherence time (T ₂) up to 27 times longer than that with a spin echo method. Consequently, we obtained an AC magnetic field sensitivity of 10.8 pt/ Hz using the dynamical decoupling pulse sequence.

Inchworm sign of endometrial cancer on diffusion-weighted MRI: radiology-pathology correlation

AIM

To perform radiology-pathology correlation of the inchworm sign on diffusion-weighted imaging (DWI) in patients with endometrial cancer.

MATERIALS AND METHODS

Consecutive patients (345) with histopathologically proven endometrial cancer who underwent preoperative magnetic resonance imaging (MRI), including DWI images, and hysterectomy were included in the present study. The inchworm sign was defined as a hypointense stalk between hyperintense endometrial cancer and hypointense myometrium on DWI images. A genitourinary pathologist reviewed the resected specimen at the site of the inchworm sign.

RESULTS

The inchworm sign on DWI images was observed in 32 (9.3%) patients. On T2-weighted images, areas of hypointense stalk on DWI images showed hypointensity in 31 (97%) patients and hyperintensity in one (3%). Among them, the depth of myometrial invasion at histopathology was superficial (<50% myometrial invasion) in 28 (87.5%) patients and deep (≥50% myometrial invasion) in four (12.5%). As a result of histopathological investigation, the hypointense stalk of the inchworm sign was mainly composed of various degrees of stromal proliferation, including smooth muscle cells and metaplastic fibromuscular stroma, with or without intervening endometrial cancer.

CONCLUSION

The inchworm sign of endometrial cancer on DWI images usually indicated superficial myometrial invasion and was caused by a stalk composed of stromal proliferation with or without intervening endometrial cancer.

Dysregulation of BMI1 and microRNA-16 collaborate to enhance an anti-apoptotic potential in the side population of refractory mantle cell lymphoma

The proto-oncogene BMI1 and its product, Bmi1, is overexpressed in various types of tumors, particularly in aggressive tumors and tumors resistant to conventional chemotherapy. BMI1/Bmi1 is also crucially involved in cancer-initiating cell maintenance, and is recurrently upregulated in mantle cell lymphoma (MCL), especially aggressive variants. Recently, side population (SP) cells were shown to exhibit tumor-initiating characteristics in various types of tumors. In this study, we show that recurrent MCL cases significantly exhibit upregulation of BMI1/Bmi1. We further demonstrate that clonogenic MCL SP shows such tumor-initiating characteristics as high tumorigenicity and self-renewal capability, and that BMI1 was upregulated in the SP from recurrent MCL cases and MCL cell lines. On screening for upstream regulators of BMI1, we found that expression of microRNA-16 (miR-16) was downregulated in MCL SP cells by regulating Bmi1 in the SPs, leading to reductions in tumor size following lymphoma xenografts. Moreover, to investigate downstream targets of BMI1 in MCL, we performed cross-linking/chromatin immunoprecipitation assay against MCL cell lines and demonstrated that Bmi1 directly regulated pro-apoptotic genes such as BCL2L11/Bim and PMAIP1/Noxa, leading to enhance anti-apoptotic potential of MCL. Finally, we found that a proteasome inhibitor bortezomib, which has been recently used for relapsed MCL, effectively induced apoptosis among MCL cells while reducing expression of Bmi1 and increasing miR-16 in MCL SP. These results suggest that upregulation of BMI1 and downregulation of miR-16 in MCL SP has a key role in the disease's progression by reducing MCL cell apoptosis. Our results provide important new insight into the pathogenesis of MCL and strongly suggest that targeting BMI1/Bmi1 might be an effective approach to treating MCL, particularly refractory and recurrent cases.

Gene cloning and characterization of the protein encoded by the Neospora caninum bradyzoite-specific antigen gene BAG1

Neospora caninum is an Apicomplexan parasite that causes repeated abortion and stillbirth in cattle. The aim of this study was to clone the gene encoding the N. caninum orthologue (NcBAG1) of the Toxoplasma gondii bradyzoite-specific protein TgBAG1 and characterize its expression pattern in the parasite. Isolation of the full-length 684-bp gene revealed that it shared 78.3% sequence similarity with TgBAG1. NcBAG1 encodes a predicted protein of 227 amino acids with 80.3% similarity to TgBAG1. A putative signal peptide sequence and an invariant GVL motif characteristic of small heat-shock proteins were identified in the predicted N. caninum amino acid sequence. We expressed the NcBAG1 gene as a recombinant glutathione S-transferase fusion protein (rNcBAG1) in Escherichia coli and used the purified 60 kDa protein to obtain a monoclonal antibody (Mab). rNcBAG1 reacted to Mabs specific for NcBAG1 and TgBAG1. No reaction between the NcBAG1 Mab and N. caninum tachyzoites was observed. Although the predicted molecular mass of NcBAG1 is 25 kDa, Western blot analysis of parasite lysates using the NcBAG1 Mab revealed a cross-reactive protein of approximately 30 kDa. Additionally, immunofluorescence assays using the tachyzoite-specific Mab for NcSAG1 and the bradyzoite-specific Mab for TgBAG1 or NcSAG4 revealed NcBAG1-specific expression in bradyzoites in cultures exposed to sodium nitroprusside, a reagent that increases the frequency of bradyzoites. Interestingly, the NcBAG1 protein was identified in the cytoplasm of the bradyzoite-stage parasites. This preliminary analysis of the NcBAG1 gene will assist investigations into the role of this protein in N. caninum .

Involvement of brown adipose tissue in subcutaneous fat necrosis of the newborn

BACKGROUND

Subcutaneous fat necrosis (SCFN) of the newborn is a rare condition that manifests within days after birth. The interscapular region, axillae and shoulders are the most commonly affected sites, corresponding to anatomic sites of brown adipose tissue (BAT) in newborns.

OBJECTIVE

We postulated a specific involvement of BAT in SCFN and searched for brown adipocytes at affected sites.

METHODS

Biopsy specimens were immunostained with antibodies against uncoupling protein 1 (UCP-1) and examined by electron microscopy. We also examined BAT by (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography and computed tomography (PET-CT) scanning.

RESULTS

A few cells in biopsy specimens from two patients bound antibodies against UCP-1, and brown adipocytes were detected at several stages of degeneration. PET-CT scans revealed lower uptake of (18)F-FDG at major sites of SCFN.

CONCLUSION

SCFN and BAT can be found at the same sites, suggesting a pathophysiological connection.

Cerebral oxygenation in the beach chair position before and during general anesthesia

AIM

Ischemic brain damage related to the beach chair position is a matter of concern. The current study was designed to evaluate whether the beach chair position before and during general anesthesia differentially induces changes in cerebral oxygenation as determined by near-infrared spectroscopy (NIRS) in surgical patients.

METHODS

We evaluated brain tissue oxygen index (TOI) values using the NIRS monitor NIRO-200TM in the beach chair position the day before and during general anesthesia. Thirty patients with normal preoperative TOI values undergoing shoulder surgery were enrolled. The initial TOI measurement in the supine position after 10 min rest or 10 min after tracheal intubation was followed by measurements after 5 min each in the 30-degree and subsequently 60-degree head-up tilt positions. During general anesthesia, patients were mechanically ventilated to obtain normocapnia under inhalation of 1.5% sevoflurane in 50% oxygen. Mean blood pressure (MAP) was measured non-invasively in the arm at heart level and was maintained above 60 mmHg with phenylephrine.

RESULTS

Preoperative TOI values and preoperative MAP were within the normal range in the study population. MAP decreased upon anesthesia but did not further change when the patient was placed in the 30- and 60-degree head-up tilt positions. Heart rate also decreased upon anesthesia. However, TOI values did not change with induction of general anesthesia or placement of the patients in the beach chair position.

CONCLUSION

Under general anesthesia, the beach chair position does not alter cerebral oxygenation in patients showing normal preoperative cerebral TOI values.