[Incidence and risk factors of anastomotic leak after transanal total mesorectal excision in China: a retrospective analysis based on national database]

Objective: Transanal total mesorectal excision (taTME) was a very hot topic in the first few years since its appearance, but now more introspections and controversies on this procedure have emerged. One of the reasons why the Norwegian Ministry of Health stopped taTME was the high incidence of postoperative anastomotic leak. In current study, the incidence and risk factors of anastomotic leak after taTME were analyzed based on the data registered in the Chinese taTME Registry Collaborative (CTRC). Methods: A case-control study was carried out. Between November 15, 2017 and December 31, 2020, clinical data of 1668 patients undergoing taTME procedure registered in the CTRC database from 43 domestic centers were collected retrospectively. After excluding 98 cases without anastomosis and 109 cases without complete postoperative complication data, 1461 patients were finally enrolled for analysis. There were 1036 males (70.9%) and 425 females (29.1%) with mean age of (58.2±15.6) years and mean body mass index of (23.6±3.8) kg/m(2). Anastomotic leak was diagnosed and classified according to the International Study Group of Rectal Cancer (ISREC) criteria. The risk factors associated with postoperative anastomotic leak cases were analyzed. The impact of the cumulative number of taTME surgeries in a single center on the incidence of anastomotic leak was evaluated. As for those centers with the number of taTME surgery ≥ 40 cases, incidence of anastomic leak between 20 cases of taTME surgery in the early and later phases was compared. Results: Of 1461 patients undergoing taTME, 103(7.0%) developed anastomotic leak, including 71 (68.9%) males and 32 (31.1%) females with mean age of (59.0±13.9) years and mean body mass index of (24.5±5.7) kg/m(2). The mean distance between anastomosis site and anal verge was (2.6±1.4) cm. Thirty-nine cases (37.9%) were classified as ISREC grade A, 30 cases (29.1%) as grade B and 34 cases (33.0%) as grade C. Anastomotic leak occurred in 89 cases (7.0%,89/1263) in the laparoscopic taTME group and 14 cases (7.1%, 14/198) in the pure taTME group. Multivariate analysis showed that hand-sewn anastomosis (P=0.004) and the absence of defunctioning stoma (P=0.013) were independently associated with anastomotic leak after taTME. In the 16 centers (37.2%) which performed ≥ 30 taTME surgeries with cumulative number of 1317 taTME surgeries, 86 cases developed anastomotic leak (6.5%, 86/1317). And in the 27 centers which performed less than 30 taTME surgeries with cumulative number of 144 taTME surgeries, 17 cases developed anastomotic leak (11.8%, 17/144). There was significant difference between two kinds of center (χ(2)=5.513, P=0.019). Thirteen centers performed ≥ 40 taTME surgeries. In the early phase (the first 20 cases in each center), 29 cases (11.2%, 29/260) developed anastomotic leak, and in the later phase, 12 cases (4.6%, 12/260) developed anastomotic leak. The difference between the early phase and the later phase was statistically significant (χ(2)=7.652, P=0.006). Conclusion: The incidence of anastomotic leak after taTME may be reduced by using stapler and defunctioning stoma, or by accumulating experience.

[Diagnosis and treatment of Chlamydia psittaci pneumonia: experiences of 8 cases]

Objective: In order to improve the understanding and clinical treatment of Chlamydia psittaci pneumonia, we analyzed the clinical manifestations, laboratory test results and imaging features of 8 patients. Methods: We collected the clinical data of 8 patients with Chlamydia psittaci pneumonia diagnosed by metagenomic next-generation-sequencing (mNGS) from November 2018 to February 2020, including clinical features, chest CT scan, pathological features and antibiotic use. Results: A total of one male and 7 females, aged from 45 to 85 years(median 62 years), were included in this study. All the patients had high fever, cough and most had expectoration (6/8). The leukocyte count and PCT level were mostly normal (7/8). However, we observed decreased lymphocyte count(5/8), elevated C-reactive protein in all patients, and increased ESR in most patients (7/8). The chest CT of all the patients showed large patchy consolidation, with one case having pleural effusion. The pathological manifestations were nonspecific, showing infiltration of inflammatory cells and exudation. Moxifloxacin and/or doxycycline were administered after diagnosis, and the course of treatment lasted from 14 to 21 days.Chest CT showed absorption of lesions following treatment Conclusions: Chlamydia psittaci pneumonia showed certain characteristics, including high fever with pulmonary patchy consolidation, and normal white blood cell count. Molecular diagnostic methods such as mNGS could lead to rapid diagnosis and treatment which can shorten the course of hospitalization and thus improve prognosis.

[Risk factors and clinical prognosis analysis of carbapenem-resistant Enterobacterales bacteria nosocomial infection]

Objective: To explore the risk factors for carbapenem-resistant Enterobacterales (CRE) infection and death. Methods: A case-control analysis of 482 inpatients in 18 secondary or tertiary hospitals in Beijing in 2018 was conducted. Patients infected by CRE were selected as the case group (n=247), and infected by carbapenem susceptible Enterobacterales (CSE) as the control group (n=235). The risk factors and clinical prognosis of CRE infection were analyzed by single factor analysis and multivariate logistic regression analysis. Results: CRE were resistant to most antimicrobials, but were highly sensitive to colistin and tigecycline, with sensitivity of 94.0% and 99.5%, respectively. Multivariate analysis showed that prior 30-day tracheal intubation (OR=2.607, 95%CI: 1.655-4.108, P<0.001), empirical treatment using third or fourth generation cephalosporins (OR=2.339, 95%CI: 1.438-3.803, P=0.001), carbapenems (OR=2.468, 95%CI: 1.610-3.782, P<0.001) and quinolones (OR=2.042, 95%CI: 1.268-3.289, P=0.003) were independent risk factors for CRE infection. Mechanical ventilation (OR=3.390, 95%CI: 1.454-7.904, P=0.005), heart failure (OR=4.679, 95%CI: 1.975-11.083, P<0.001), moderate or severe liver disease (OR=3.057, 95%CI: 1.061-8.806, P=0.038), prior 30-day quinolones exposure (OR=2.882, 95%CI: 1.241-6.691, P=0.014) and septic shock (OR=7.772, 95%CI: 3.505-17.233, P<0.001) were independent risk factors for death after CRE infection. Conclusions: Reducing the use of antimicrobials and invasive procedures such as prior 30-day tracheal intubation may reduce the probability of CRE infection. Grading the severity of the underlying disease in patients with CRE infection, as well as predicting and preventing the occurrence of septic shock will help reduce the risk of death.

POS0776 CORRELATION OF PERIPHERAL CD4+GRANZB+CTLS WITH DISEASE SEVERITY IN PATIENTS WITH PRIMARY SJÖGREN’S SYNDROME

Background:

Sjögren’s syndrome (SS) is a chronic autoimmune disorder. The major histopathologic lesion of it is a focal lymphocytic infiltrate around ductal and acinar epithelial cells, which include a majority of CD4+T. Several studies have shown that the epithelial cells in SS present diverse phenomena, such as MHC class II overexpression. CD4+T cells with cytotoxic activity (CD4 CTL) have been detected in various immune responses. They are characterized by their ability to secrete perforin and granzyme B to kill the target cells in an MHC class II-restricted fashion.

Objectives:

So this study was to investigate the correlation of peripheral CD4+GranzB+CTLs with disease severity and organ involvement in patients with primary Sjögren’s syndrome.

Methods:

We recruited 116 pSS patients and 46 healthy controls using flow cytometry to examine proportion of CD4+GranzB+CTLs in their peripheral blood, and immunofluorescence to test the expression of CD4+GranzB+CTLs in labial gland. The correlations of CD4+GranzB+CTLs and the relevant clinical data were analyzed.

Results:

We analyzed the percentage of CD4+GranzB+cytotoxic T cells in peripheral blood mononuclear cells (PBMCs) by flow cytometry. Frequency of peripheral CD4+GranzB+CTLs were measured in 116 patients with pSS and 46 healthy controls matched for age and sex. The percentage of CD4+GranzB+CTLs were significantly up-regulated in pSS patients than healthy controls (7.1%±4.9% vs 3.1%±1.9%, p <0.0001) and positive correlation with ESSDAI in pSS patients(r = 0.6332, p<0.001). The percentage of CD4+GranzB+CTLs were markedly higher in pSS patients with extraglandular manifestations. Moreover, CD4+GranzB+CTLs were observed in the lymphocytic foci and periductal areas of the LSGs and were elevated with increased foci index (FI). After excluding the other risk factors associated with pSS, CD4+GranzB+CTLs were still related to ESSDIA and extraglandular manifestations independently(p<0.05). ROC curve analysis indicated that the area under the curve (AUC) of CD4+GranzB+CTLs was 0.796 to predict the activity of pSS, and 0.851 to presume extraglandular manifestations. The best diagnostic cut-off point was 4.865 for pSS patients.

Conclusion:

In this study, We provide new evidence indicating involvement of CD4+GranzB+CTLs over activation in the disease pathophysiology of pSS, which may serve as a new biomarker to evaluate the activity and severity of pSS.

References:

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Table 1.

Multivariate analysis of CD4+GranzB+CTLs influenced by pSS-related factors

regression coefficientstandard errort-statisticsp value95%CICD8+GranzB+CTLs(%)0.1440.0334.3346.9E-50.077, 0.211ESSDAI0.2560.1222.0950.0410.011, 0.502extraglandular manifestations2.6121.2682.0590.0450.065, 5.158Figure 1.

Receiver operating characteristic (ROC) curve of the frequency of CD4+GranzB+CTLs to predict ESSDAI and extraglandular manifestations response

Disclosure of Interests:

None declared

The value of 18F-FDG PET/CT imaging combined with detection of CA125 and HE4 in the diagnosis of recurrence and metastasis of ovarian cancer

OBJECTIVE

To explore the clinical application value of 18F-fluorodeoxyglucose (18F-FDG) PET/CT imaging combined with detection of serum tumor molecular markers (carbohydrate antigen 125 (CA 125) and human epididymis protein 4 (HE4)) in the diagnosis of recurrence and metastasis of ovarian cancer.

PATIENTS AND METHODS

Clinical data about 18F-FDG PET/CT imaging and serum CA125 and HE4 of 69 ovarian cancer patients after the first cytoreductive surgery and chemotherapy were retrospectively analyzed, and the clinical application value of 18F-FDG PET/CT imaging combined with detection of CA125 and HE4 in the diagnosis of recurrence and metastasis of ovarian cancer was evaluated.

RESULTS

The 18F-FDG PET/CT images of recurrence and metastasis of ovarian cancer showed hypermetabolism. The sensitivity, specificity, accuracy, predictive positive value, and predictive negative value of 18F-FDG PET/CT imaging for the diagnosis of recurrence and metastasis of ovarian cancer were 90.74%, 86.67%, 89.86%, 96.08%, and 72.22%, respectively; those of CA125 for the diagnosis of them were 77.78%, 86.67%, 79.71%, 95.45% and 52.00%, respectively, and those of HE4 for the diagnosis of them were 70.37%, 93.33%, 76.84%, 97.44%, and 48.39% respectively. In addition, the sensitivity and specificity of 18F-FDG PET/CT combined with detection of serum CA125 and HE4 for the diagnosis were 100.00% and 100.00%, respectively, significantly higher than those of separate 18F-FDG PET/CT imaging, detection of serum CA125, and detection of serum HE4 (c2 = 5.243, 13.500, 18.783, p = 0.022, 0.000, 0.000; c2 = 4.000, 8.525, 9.864, p = 0.046, 0.004, 0.002), and the accuracy of the combination use of them was 95.65%, also significantly higher than that of separate CA125 and HE4 (c2 = 8.118, 10.315, p = 0.004, 0.001, both p < 0.01). Furthermore, the maximum standardized uptake value (SUVmax) of 18F-FDG PET/CT imaging for recurrence and metastasis of ovarian cancer focuses was significantly positively correlated with serum CA125 and HE4 levels (r = 0.596, p = 0.000; r = 0.431, p = 0.002), and the serum CA125 level was also significantly positively correlated with serum HE4 level in patients with recurrent or metastasized ovarian cancer (r = 0.198, p = 0.043,).

CONCLUSIONS

18F-FDG PET/CT imaging combined with detection of serum CA125 and HE4 can significantly improve the diagnostic efficiency to recurrence and metastasis of ovarian cancer and is conducive to the early diagnosis of the recurrence and metastasis, which provides a basis for further clinical intervention.

Continuous and discontinuous transitions in the depinning of two-dimensional dusty plasmas on a one-dimensional periodic substrate

Langevin dynamical simulations are performed to study the depinning dynamics of two-dimensional dusty plasmas on a one-dimensional periodic substrate. From the diagnostics of the sixfold coordinated particles P_{6} and the collective drift velocity V_{x}, three different states appear, which are the pinning, disordered plastic flow, and moving ordered states. It is found that the depth of the substrate is able to modulate the properties of the depinning phase transition, based on the results of P_{6} and V_{x}, as well as the observation of hysteresis of V_{x} while increasing and decreasing the driving force monotonically. When the depth of the substrate is shallow, there are two continuous phase transitions. When the potential well depth slightly increases, the phase transition from the pinned to the disordered plastic flow states is continuous; however, the phase transition from the disordered plastic flow to the moving ordered states is discontinuous. When the substrate is even deeper, the phase transition from the pinned to the disordered plastic flow states changes to discontinuous. When the depth of the substrate further increases, as the driving force increases, the pinned state changes to the moving ordered state directly, so that the disordered plastic flow state disappears completely.

[Influence of comprehensive incubational measures on the perioperative treatment of extensively burned patients who underwent escharectomy and skin grafting]

Objective: To explore the influence of standardized and comprehensive incubational measures on perioperative treatment of extensively burned patients who underwent escharectomy and skin grafting. Methods: From January 2017 to November 2018, 50 patients with extensive burn who underwent escharectomy and skin grafting in the First Affiliated Hospital of Air Force Medical University and met the inclusion criteria of this study, were recruited in this retrospective cohort study. According to the incubational measures at that time, 20 patients (14 males and 6 females, aged (33.5±5.2) years) who received routine incubation during the perioperative period from January to October 2017 were set as routine incubation group, and 30 patients (23 males and 7 females, aged (35.8±1.4) years) who received standardized comprehensive incubational measures during the perioperative period from November 2017 to November 2018 were set as comprehensive incubation group. Their body temperature was controlled mainly in 4 stages: preoperative preparation and transfer from intensive care unit (ICU) to operating room, preoperative preparation in operating room, intraoperative operating room management, as well as postoperative transfer from operating room to ICU. The initial body temperature in operating room and intraoperative hypothermia duration, intraoperative blood loss, postoperative recovery time, postoperative chill, blister, and ulcer, and wound healing rate on post operation day (POD) 10 were recorded and calculated. Data were statistically analyzed with two independent samples t test and chi-square test. Results: (1) The initial body temperature in operating room of patients in comprehensive incubation group was (36.3±0.4) ℃, which was significantly higher than (35.6±0.4)℃ in routine incubation group, t=6.658, P<0.01; the intraoperative duration of hypothermia was (205±38) min, which was significantly shorter than (234±42) min in routine incubation group, t=2.564, P<0.05. (2) The intraoperative blood loss of patients in comprehensive incubation group was (323±114) mL, which was significantly less than (490±162) mL in routine incubation group, t=4.272, P<0.01; the postoperative recovery time was (36±8) min, which was significantly shorter than (49±17) min in routine incubation group, t=3.229, P<0.01. (3) The incidence of postoperative chill of patients in comprehensive incubation group was significantly lower than that in routine incubation group (χ(2)=28.626, P<0.01). The incidences of postoperative blister and ulcer of patients between the 2 groups were close. (4) On POD 10, the wound healing rate of patients in comprehensive incubation group was (78.08±0.06)%, which was significantly higher than (71.03±0.08)% in routine incubation group, t=3.694, P<0.01. Conclusions: The standardized and comprehensive incubational measures can effectively improve the initial body temperature of patients entering the operating room, shorten the intraoperative duration of hypothermia, reduce the amount of blood loss and postoperative complications, as well as shorten the postoperative recovery time, thus improve the wound healing rate.

First Measurement of Differential Charged Current Quasielasticlike ν_{μ}-Argon Scattering Cross Sections with the MicroBooNE Detector

We report on the first measurement of flux-integrated single differential cross sections for charged-current (CC) muon neutrino (ν_{μ}) scattering on argon with a muon and a proton in the final state, ^{40}Ar (ν_{μ},μp)X. The measurement was carried out using the Booster Neutrino Beam at Fermi National Accelerator Laboratory and the MicroBooNE liquid argon time projection chamber detector with an exposure of 4.59×10^{19} protons on target. Events are selected to enhance the contribution of CC quasielastic (CCQE) interactions. The data are reported in terms of a total cross section as well as single differential cross sections in final state muon and proton kinematics. We measure the integrated per-nucleus CCQE-like cross section (i.e., for interactions leading to a muon, one proton, and no pions above detection threshold) of (4.93±0.76_{stat}±1.29_{sys})×10^{-38}  cm^{2}, in good agreement with theoretical calculations. The single differential cross sections are also in overall good agreement with theoretical predictions, except at very forward muon scattering angles that correspond to low-momentum-transfer events.

Application of Artificial Intelligence in Dentistry

Artificial intelligence (AI) is a technology that utilizes machines to mimic intelligent human behavior. To appreciate human-technology interaction in the clinical setting, augmented intelligence has been proposed as a cognitive extension of AI in health care, emphasizing its assistive and supplementary role to medical professionals. While truly autonomous medical robotic systems are still beyond reach, the virtual component of AI, known as software-type algorithms, is the main component used in dentistry. Because of their powerful capabilities in data analysis, these virtual algorithms are expected to improve the accuracy and efficacy of dental diagnosis, provide visualized anatomic guidance for treatment, simulate and evaluate prospective results, and project the occurrence and prognosis of oral diseases. Potential obstacles in contemporary algorithms that prevent routine implementation of AI include the lack of data curation, sharing, and readability; the inability to illustrate the inner decision-making process; the insufficient power of classical computing; and the neglect of ethical principles in the design of AI frameworks. It is necessary to maintain a proactive attitude toward AI to ensure its affirmative development and promote human-technology rapport to revolutionize dental practice. The present review outlines the progress and potential dental applications of AI in medical-aided diagnosis, treatment, and disease prediction and discusses their data limitations, interpretability, computing power, and ethical considerations, as well as their impact on dentists, with the objective of creating a backdrop for future research in this rapidly expanding arena.

MOTS-c improves osteoporosis by promoting the synthesis of type I collagen in osteoblasts via TGF-β/SMAD signaling pathway

OBJECTIVE

To investigate whether MOTS-c can regulate the synthesis of type I collagen in osteoblasts by regulating TGF-β/SMAD pathway, thereby improving osteoporosis.

MATERIALS AND METHODS

Viability of hFOB1.19 cells treated with MOTS-c was detected by CCK-8 assay. The mRNA and protein levels of TGF-β, SMAD7, COL1A1 and COL1A2 in hFOB1.19 cells were detected by quantitative Real-time polymerase chain reaction (qRT-PCR) and Western blot, respectively. We then changed expressions of TGF-β and SMAD7 by plasmids transfection to detect levels of COL1A1 and COL1A2 in hFOB1.19 cells by qRT-PCR and Western blot, respectively.

RESULTS

Cell viability was significantly increased after treatment of 1.0 μM MOTS-c for 24 h or 0.5 μM MOTS-c for 48 h in a time-dependent manner. The mRNA and protein expressions of TGF-β, SMAD7, COL1A1 and COL1A2 in hFOB1.19 cells were dependent on the concentration of MOTS-c. In addition, MOTS-c increased the expressions of COL1A1 and COL1A2, which were partially reversed by knockdown of TGF-β or SMAD7.

CONCLUSIONS

MOTS-c could promote osteoblasts to synthesize type I collagen via TGF-β/SMAD pathway.

Soft Ring-Shaped Cellu-Robots with Simultaneous Locomotion in Batches

Untethered mini-robots can move single cells or aggregates to build complex constructs in confined spaces and may enable various biomedical applications such as regenerative repair in medicine and biosensing in bioengineering. However, a significant challenge is the ability to control multiple microrobots simultaneously in the same space to operate toward a common goal in a distributed operation. A locomotion strategy that can simultaneously guide the formation and operation of multiple robots in response to a common acoustic stimulus is developed. The scaffold-free cellu-robots comprise only highly packed cells and eliminate the influence of supportive materials, making them less cumbersome during locomotion. The ring shape of the cellu-robot contributes to anisotropic cellular interactions which induce radial cellular orientation. Under a single stimulus, several cellu-robots form predetermined complex structures such as bracelet-like ring-chains which transform into a single new living entity through cell-cell interactions, migration or cellular extensions between cellu-robots.

First Measurement of Inclusive Muon Neutrino Charged Current Differential Cross Sections on Argon at E_{ν}∼0.8 GeV with the MicroBooNE Detector

We report the first measurement of the double-differential and total muon neutrino charged current inclusive cross sections on argon at a mean neutrino energy of 0.8 GeV. Data were collected using the MicroBooNE liquid argon time projection chamber located in the Fermilab Booster neutrino beam and correspond to 1.6×10^{20} protons on target of exposure. The measured differential cross sections are presented as a function of muon momentum, using multiple Coulomb scattering as a momentum measurement technique, and the muon angle with respect to the beam direction. We compare the measured cross sections to multiple neutrino event generators and find better agreement with those containing more complete treatment of quasielastic scattering processes at low Q^{2}. The total flux integrated cross section is measured to be 0.693±0.010(stat)±0.165(syst)×10^{-38}  cm^{2}.

Liquid-like behaviours of metallic glassy nanoparticles at room temperature

Direct atomic-scale observations and measurements on dynamics of amorphous metallic nanoparticles (a-NPs) are challenging owing to the insufficient consciousness to their striking characterizations and the difficulties in technological approaches. In this study, we observe coalescence process of the a-NPs at atomic scale. We measure the viscosity of the a-NPs through the particles coalescence by in situ method. We find that the a-NPs have fast dynamics, and the viscosity of the a-NPs exhibits a power law relationship with size of the a-NPs. The a-NPs with sizes smaller than 3 nm are in a supercooled liquid state and exhibit liquid-like behaviours with a decreased viscosity by four orders of magnitude lower than that of bulk glasses. These results reveal the intrinsic flow characteristics of glasses in low demension, and pave a way to understand the liquid-like behaviours of low dimension glass, and are also of key interest to develop size-controlled nanodevices.

Nanoscale materials often exhibit size-dependent behaviour. Here, the authors use electron microscopy to quantitatively study the size-related dynamics of amorphous metallic nanoparticles, finding that particles below a critical size are in a supercooled liquid state at room temperature, with a viscosity much lower than that of bulk glasses.

Clinical and radiographic characterization of primary seminomas and nonseminomatous germ cell tumors

Background

Primary malignant mediastinal germ cell tumors (PMMGCTs) including seminomas and nonseminomatous germ cell tumors (NSGCTs) are rare, and sometimes the diagnosis is very difficult.

Purpose

The purpose of this study is to compare the clinical characteristics, biomarkers, and imaging findings of seminomas and NSGCTs and to determine whether these features could help distinguish these two types of PMMGCT.

Material and Methods

A retrospective study of 24 male patients with histopathologically proven PMMGCT was performed. We collected the information of computed tomography (CT) (the scan area ranged from the apex of lung to the costophrenic angles) and magnetic resonance imaging blood test and histology characteristics of these patients.

Results

Twelve of 24 cases were confirmed to be seminomas, whereas the other 12 cases were NSGCTs. Alfa-fetoprotein (AFP) was found to be elevated in all patients with NSGCT, whereas none of the patients with seminomas had elevated AFP level. Beta-human chorionic gonadotropin (β-HCG) level was elevated in all the patients with seminomas (seven/seven), whereas in NSGCT only two of seven patients had elevated β-HCG. Lactate dehydrogenase level was increased in five of the nine patients with seminomas, as well as in the eight patients with NSGCT. CT imaging revealed that 12 masses from the seminoma group were homogeneous, soft tissue opacity and showed minimal contrast enhancement. On the contrary, all 12 NSGCT cases showed cystic and solid masses; on contrast-enhanced CT, heterogeneous enhancement was found on the capsule of the tumor, septum, and solid masses.

Conclusion

Seminomas and NSGCT showed different profiles of tumor biomarkers and radiographic features. Evidence from serum test, histopathological analysis, and imaging should be combined to ensure the accurate diagnosis of these two types of PMMGCT.

Abstract P6-01-02: Machine learning-based structural analysis and oxygen saturation measurement of tumor-associated vessels in breast cancer using a photoacoustic tomography system

Introduction

Breast cancer induces angiogenesis, one of the primary factors responsible for tumor progression. Therefore, the ability to visualize angiogenesis at a higher resolution is crucial. Photoacoustic tomography is a noninvasive method of visualizing angiogenesis involving light absorption and ultrasonic wave emission. If the irradiation light wavelength is adjusted for hemoglobin, vascular imaging is possible. Furthermore, using two wavelengths for oxidized and reduced hemoglobin, “S-factor,” can be calculated, which nearly corresponds to oxygen saturation. Therefore, photoacoustic imaging allows the assessment of breast lesions from vascular structural and functional viewpoints.

Objectives

This study aimed to demonstrate the possible utility of photoacoustic tomography for clinical application focusing on the morphologic features and oxygen saturation status of breast tumor-related vessels.

Methods

For the morphological analysis, we applied a machine learning-based method for automatic vessel extraction, and for the functional analysis we evaluated hemoglobin oxygen saturation calculating signals obtained at two wavelengths. In our system, a 3D ultrasound image was simultaneously acquired as a volume image of a tumor, which helped analyze the positional relationship between the vessels and the tumor.

Results

On morphological analysis, the fine structure of tumor-related vessels was rendered in high resolution. In our system, the blood vessels branched toward the tumor 2-3 more times more frequently than observed on contrast-enhanced MRI, illustrating a finer level of blood vessels near the tumor on our system than on MRI. Next, we analyzed the six morphologic features of vessels (radius, volume, curvature, contraction, maximum angle and vessel branch number) that are associated with the pathologic condition in neuroscience. We determined that the feature distribution of vessels located close to the tumor differed from that located away from the tumor. For example, vessels near the tumor had higher curvature, which means they are more tortuous than healthy vessels. The difference in the distribution of all six features was statistically significant on the Kolmogorov-Smirnov test.

On functional analysis, S-factor measurement of the healthy human breast demonstrated clearly demarcated arteries and veins. The S-factor of any artery was nearly 100%, while that of the veins inside the breast cancer tended to be a little higher (approximately 5%) compared to that in the healthy part. This tendency of veins was not recognized in benign tumors. This could show arteriovenous shunt in cancer microenvironment. We found low saturation signals emerging in the tumor tissue following bevacizumab-containing chemotherapy, indicating the possibility that our system reveals microenvironment changes.

Discussion

If our system can identify the structure or oxygen saturation characteristics unique to tumor-associated vasculature, it could contribute to the improved accuracy of breast cancer diagnosis and allow the observation of tumor vessel normalization because of the drug treatment. An earlier grasp of the therapeutic effect could lead to the provision of individualized medicine.

Citation Format: Matsumoto Y, Gu L, Bise R, Asao Y, Sekiguchi H, Yoshikawa A, Ishii T, Takada M, Kataoka M, Sakurai T, Yagi T, Sato I, Togashi K, Shiina T, Toi M. Machine learning-based structural analysis and oxygen saturation measurement of tumor-associated vessels in breast cancer using a photoacoustic tomography system [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-01-02.

Land-Atmosphere Responses to a Total Solar Eclipse in Three Ecosystems With Contrasting Structure and Physiology

Mid-Missouri experienced up to 2 min 40 s of totality at around solar noon during the total eclipse of 2017. We conducted the Mid-Missouri Eclipse Meteorology Experiment to examine land-atmosphere interactions during the eclipse. Here, research examining the eclipse responses in three contrasting ecosystems (forest, prairie, and soybeans) is described. There was variable cloudiness around first and fourth contacts (i.e., the start and end of partial solar obscuration) at the forest and prairie; however, solar irradiance (K _↓) signals during the eclipse were relatively clean. Unfortunately, the eclipse forcing at the soybean field was contaminated by convective activity, which decreased K _↓ beginning about an hour before first contact and exposed the field to cold outflow ~30 min before second contact. Turbulence was suppressed during the eclipse at all sites; however, there was also an amplified signal at the soybean field during the passage of a gust front. The standard deviations of the horizontal and vertical wind velocities and friction velocities decreased by ~75% at the forest (aerodynamically rough), and ~60% at the prairie (aerodynamically smooth). The eddy fluxes of energy were highly coherent with the solar forcing with the latent and sensible heat fluxes approaching 0 W/m² and changing in direction, respectively. For the prairie site, we estimated a canopy-scale time constant for the surface conductance light response of 10 min. Although the eclipse imparted large forcings on surface energy balances, the air temperature response was relatively muted (1.5-2.5 °C decrease) due to the absence of topographic effects and the relatively moist land and atmosphere.