[Effect of peri-implant soft-tissue phenotype on peri-implant health].

Dental implant is a commonly used therapeutic option for reconstruction of edentulous space. Adequate peri-implant soft tissue is crucial for preventing biological and esthetic complications. Peri-implant soft-tissue phenotypes including supracrestal tissue height, mucosa thickness and keratinized mucosa width could reflect the quality and quantity of peri-implant soft tissue. Different soft-tissue phenotypes might impact the stability of implant restoration through altering the tissue remodeling or inflammatory response. This review will discuss the influence of peri-implant soft-tissue phenotypes on tissue remodeling and inflammatory response after implant placement.

[Associations of blood pressure change with change in foods' intake among adults with mild to moderate hypertension].

Objective: To explore the association between the intake and changes in various types of food and the changes in blood pressure in patients with mild to moderate hypertension. Methods: Mild to moderate hypertension participants with complete baseline and outcome data were included from DECIDE-Diet study, a multicenter, randomized controlled trial. Dietary records and blood pressure measurements at both 7-day run-in (baseline) and 28-day intervention phases were collected for enrolled participants. Blood pressure change was defined as the difference between blood pressure at the end of trial and the baseline blood pressure. Baseline intake of food was the average daily intake during the run-in period, and the intake increment was defined as the difference between the average intake during the trial period and the average intake during the run-in period. After adjusting for age, sex, study center, intervention groups, baseline body mass index (kg/m2), antihypertension medication use, and baseline total calorie intake, a linear regression model was used to analyze the associations of the before-after-intervention change in blood pressure with baseline intake and intake increment of foods. Results: A total of 258 patients with mild to moderate hypertension were included, including 133 males, aged (56.5±9.9) years. (1) After adjusting for confounding factors, there was no significant association between baseline intake of food and baseline blood pressure (all P>0.05). The blood pressure change was negatively associated with baseline intakes of tubers, vegetables, and vegetable oils but positively with baseline intake of meats; and was negatively associated with intake increment of whole grains and fish (all P<0.05). (2) The multiple linear regression analysis showed that baseline intake of vegetables (ß=-0.021, P=0.004), vegetable oils (ß=-0.260, P=0.002), and increment in intake of fish (ß=-0.128, P=0.026) were all significantly associated with changes in systolic blood pressure; baseline intake of vegetables (ß=-0.017, P=0.002), vegetable oils (ß=-0.182, P=0.001), dairy products (ß=0.021, P=0.022), and increment in intake of fish (ß=-0.092, P=0.010) were all significantly associated with changes in diastolic blood pressure. Conclusion: Increasing the intake of whole grains, vegetables, vegetable oils, and fish and decreasing the intake of meat may be beneficial for blood pressure control in patients with mild to moderate hypertension.

[Evaluation of the efficacy of TIPS in 27 patients with hepatic sinus obstruction syndrome in the near and medium term].

Objective: intrahepatic portocaval shunt (TIPS) in the treatment of hepatic sinusoidal obstruction syndrome (HSOS). Methods: A retrospective analysis was performed on 27 patients with HSOS who were treated with TIPS in our center from July 2018 to July 2020. The changes of portal vein pressure (PVP), portal vein pressure gradient (PPG) and liver function were observed, so as to evaluate the efficacy. Paired t test was adopted to evaluate the quantitative parameters, while χ (2) test was used to analyze qualitative parameters, with P < 0.05 as statistical difference. Results: PVP decreased from (4.41 ± 0.18) kPa before shunt to (2.69 ± 0.11) kPa after shunt (t = 82.41, P < 0.001), PPG decreased from (3.23 ± 0.18) kPa before shunt to (1.46 ± 0.23) kPa after shunt (t = 32.41, P < 0.001). The liver function improved significantly after operation. After 24 months of follow-up, 3 patients developed stent restenosis and recanalized after balloon dilation. Three patients developed hepatic encephalopathy, which was improved after drug treatment. One patient underwent liver transplantation due to liver failure. Conclusion: TIPS is effective in the treatment of HSOS in the short and medium term, and can provide time for liver transplantation patients to wait for liver source.

[Preliminary survey report on the clinical validation of in-use electronic sphygmomanometers in China].

Objective: To explore the percentage of in-use electronic sphygmomanometers independently validated clinically in China. Methods: We conducted a cross-sectional survey and Beijing, Shenzhen, Shijiazhuang, Datong, and Shihezi were selected according to the geographical location and economic level. In each site, one tertiary hospital, two community health centers, and 20 families with electronic sphygmomanometers in use were chosen. The information of electronic sphygmomanometers including brand, model, manufacturer and production date were obtained by the trained staff. Ten electronic sphygmomanometers from each hospital, five electronic sphygmomanometers from each community health center, and one electronic sphygmomanometer from each family were surveyed, and the user's subjective judgment results and judgment basis on the accuracy of the electronic sphygmomanometer measurement were collected. We searched six registration websites (Medaval, Stride BP, dabl Educational Trust, British and Irish Hypertension Society, American Medical Association and Hypertension Canada) and two research databases (PubMed and CNKI) for the clinical validation status of each electronic sphygmomanometer. Results: A total of 200 electronic sphygmomanometers were investigated in this study, of which only 29.0% (58/200) passed independent clinical validation. When stratified by users, the percentage of being clinical validated was 46.0% (23/50) for electronic sphygmomanometers in hospitals, 42.0% (21/50) for those in community health centers and 14.0% (14/100) for those in home use, respectively, and the proportions between the three groups were significantly difference (P<0.001). Doctors in tertiary hospitals and community health service centers judged the accuracy of electronic sphygmomanometers mainly on the basis of "regular correction" (41.0% (41/100)) and "comparison with other electronic sphygmomanometers" (20.0% (20/100)), while among home users, 41.0% (41/100) were not clear about the accuracy of electronic sphygmomanometers, and 40.0% (40/100) made the judgment by "comparison with the devices in hospitals". Conclusion: The clinical validation of in-use electronic sphygmomanometers in China is low. Most of users, including healthcare professionals, are not aware of clinical validation of electronic sphygmomanometers.

[Interaction of polycyclic aromatic hydrocarbon DNA adducts and telomere length on missed abortion].

Objective: To analyze the contribution and interaction of polycyclic aromatic hydrocarbons (PAH)-DNA adducts and changes of telomere length (TL) on missed abortion. Methods: From March to December 2019, patients with missed abortion in the First Hospital of Shanxi Medical University and pregnant women with normal pregnancy but voluntary abortion in the same department during the same period were selected and divided into a case group and a control group. Questionnaire was used to investigate the general situation and the pregnancy situation of the subjects. The abortion villi were collected and the content of PAH-DNA adducts and TL was detected. Logistic regression model was used to analyze the associated factors of missed abortion. R epiR package and Mediation package were used to analyze the effect and relationship between PAH-DNA adducts and TL on missed abortion. Results: The age of the subjects was(29.92±5.69)years old. The M(Q1,Q3)of PAH-DNA adducts was 453.75(404.61, 504.72) pg/ml. The M(Q1,Q3)of TL was 1.21(0.77, 1.72). The content of PAH-DNA adducts in the case group was higher than that in the control group (Z=-2.10, P=0.036), while the TL was lower than that in the control group (Z=-4.05, P<0.001). Multivariate logistic regression showed that low, medium and high levels of PAH-DNA adducts (OR=3.17,95%CI:1.41-7.14;OR=2.85,95%CI:1.25-6.52;OR=2.46,95%CI:1.07-5.64), and long, medium and short levels of TL (OR=2.50,95%CI:1.11-5.63;OR=3.32,95%CI:1.45-7.56;OR=3.22,95%CI:1.42-7.26) were all risk factors for missed abortion. The medium level of PAH-DNA adducts had a 2.76-fold higher risk of shortened TL than those with the lowest level, and no mediating role of TL was found. The stratified analysis showed that when the TL level was longer (>1.21), the low and high levels of PAH-DNA adducts were associated with missed abortion (all P<0.05); when the TL level was shorter (<1.21), the medium level of PAH-DNA adducts was associated with abortion (P=0.025). At lower levels of PAH-DNA adducts, no effect of TL on missed abortion was observed, while, at higher levels, TL was strongly associated with missed abortion (OR=7.50,95%CI:1.95-28.82;OR=6.04,95%CI:1.54-23.65;OR=9.05,95%CI:2.34-35.04). The interaction analysis found that the AP was 0.72 (95%CI: 0.46-0.99), and the SI was 5.21 (95%CI: 2.30-11.77). Conclusion: The high level of PAH-DNA adducts and shortened TL may increase the risk of missed abortion, and there may be a positive additive interaction between the two factors on missed abortion.

[Application of bridging study design in preventive vaccine clinical trials].

Bridging study in vaccine clinical trials means a series of small-scale additional tests on the basis that the original safety and effectiveness of a vaccine have been confirmed in clinical trials, to prove that the characteristics of safety, immunogenicity and effectiveness of a vaccine are similar or consistent after component, population and immunization procedure change to other types which can extrapolate data from existing clinical trials. Compared with traditional vaccine clinical trials, bridging trials can promote the approval of vaccines to the market, accelerate the expansion of vaccine application, and promote the use of vaccines across regions and populations. In recent years, the application of bridge study design in vaccine clinical research has become more and more common. In order to better guide and promote the application of bridging trial design in the field of vaccine clinical research, we reviewed the design characteristics and application examples of bridging study design in vaccine clinical trials, and systematically elaborated the design ideas, key points and statistical evaluation methods of bridging study.

[Study on the correlation between PPG and HVPG in patients with portal hypertension].

Objective: To explore the correlation between portal vein pressure gradient (PPG) and hepatic vein pressure gradient (HVPG) in patients with portal hypertension (PHT). Methods: 752 cases with portal hypertension (PHT) who underwent transjugular intrahepatic portosystemic shunt (TIPS) and met the enrollment criteria between January 2016 to December 2019 were analyzed for hepatic vein, inferior vena cava and portal vein pressure. Paired t-test was used for analysis. Pearson correlation test was used to estimate correlation coefficient and coefficient of determination. P<0.05 were considered statistically significant. Results: Wedged hepatic vein pressure (WHVP), portal vein pressure (PVP), correlation coefficient, and coefficient of determination were 27.98±8.95 mmHg, 33.85±7.33 mmHg, 0.329 (P<0.001), and 0.108, respectively. HVPG, PPG,correlation coefficient, and coefficient of determination were 16.84±7.97 mmHg, 25.11±6.95 mmHg (P<0.001), 0.145, and 0.021 (P<0.001), respectively. The difference between HVPG and PPG was greater than 5 mmHg in 524 cases, accounting for 69.7%. The difference between HVPG and PPG was within 5 mmHg or basically equal in 228 cases, accounting for 30.3%. The correlation coefficient between free hepatic venous pressure (FHVP) and inferior vena cava pressure (IVCP) was 0.568 (P<0.001), and the coefficient of determination was 0.323. According to the presence or absence of hepatic venous collaterals after balloon occluded hepatic angiography, they were divided into two groups: 157 (20.9%) cases in the group with hepatic venous collaterals, and 595 (79.1%) cases in the group without hepatic venous collaterals. The parameters of the two groups were compared: WHVP (15.73±3.63) mmHg vs. (31.22±6.90) mmHg, P<0.001; PVP (31.69±8.70) mmHg vs. (34.42±6.81) mmHg, P<0.001; HVPG (7.18±4.40) mmHg vs. (19.40±6.62) mmHg, P<0.001; PPG (24.24±8.11) mmHg vs. (25.34±6.60) mmHg, P<0.001; free hepatic venous pressure (FHVP) (8.58±3.37) mmHg vs. (11.82±5.07) mmHg , P<0.001; inferior vena cava pressure (IVCP) (7.45±3.29) mmHg vs. (9.09±4.14) mmHg, P<0.001. Conclusion: The overall correlation is poor between HVPG and PPG. HVPG of most patients is not an accurate representation of PPG, and the former is lower than the latter. Hepatic venous collateral formation is one of the important reasons for the serious underestimation of HVPG values.

[Oral microbiome dysbiosis triggers gestational periodontal disease and adverse pregnancy outcomes].

Oral microbiome dysbiosis, triggered by increased oral pathogens or decreased commercial bacteria, leads to oral and systemic diseases. Recent ecological events suggest that periodontal disease is a risk factor of adverse pregnancy outcomes. The oral microbiome dysbiosis is believed to be associated with oral disease and adverse pregnancy outcomes (APO). However, the pathogenic mechanisms have not yet been elucidated. In this review, we summarize the recent literature on how pregnancy associated pathogenic oral microbiome dysbiosis can trigger gestational periodontal diseases and poor birth outcomes, especially the role of periodontal pathogenic bacteria in the mechanisms of how gestational periodontal diseases cause APO, and the effect of periodontal therapy during pregnancy on birth outcomes.

[Analysis of 53 cases of transjugular liver biopsy].

Objective: To investigate the practicability and safety of transjugular liver biopsy (TJLB). Methods: Data of 53 cases with transjugular liver biopsy from June 2015 to June 2020 were collected. LABS-100 was used in all patients who underwent transjugular liver biopsy. Among them, 45 cases and eight were biopsied via hepatic vein and intrahepatic segment of the inferior vena cava. The surgical indications, related complications, and postoperative pathological diagnosis were analyzed and summarized. Results: TJLB was successful in all patients, with an average of 2.8 punctures per case. Satisfactory liver tissue and histopathological diagnosis was obtained in all patients. Two cases developed a cervical hematoma that was improved spontaneously, and one patient developed an intrahepatic hematoma that was improved after conservative treatment. Conclusion: TJLB is a practical and safe method for patients with contraindications to percutaneous liver biopsy.

[Progress on the application of data mining in the prognosis of cardiovascular disease].

Data mining has been widely used in the study of cardiovascular disease prognosis. For stroke prognosis, the focus was mainly on the prediction of intervention effectiveness. In contrast, the focus was primarily on predicting natural prognostic and intervention safety for other cardiovascular diseases. In addition, compared with traditional statistical methods, machine learning, especially deep learning based on neural networks has much better performance in predicting the prognosis of cardiovascular diseases, which is worthy of further promotion and application. Therefore, this study systematically reviewed the recent application progress of data mining in cardiovascular disease prognosis, summarized the shortcomings of current studies, and put forward future directions.

[Measurement and evaluation of the quadriceps muscle mass in young men based on magnetic resonance imaging].

OBJECTIVE: To investigate the correlation between the quadriceps cross-sectional area (CSA) and quadriceps muscle volume (QMV) at different horizontal levels from the upper edge of the patella, and to determine the best observation position. METHODS: Thigh magnetic resonance imaging (MRI) images of 22 Chinese young men [age: (29±6) years] with anterior cruciate ligament (ACL) rupture were examined. The CSA was measured at 18, 15, and 12 cm above the upper edge of the pate-lla (denoted by CSA-18, CSA-15 and CSA-12 respectively), and the QMV and CSA were determined by semiautomatic segmentation. A curve model was established to estimate QMV. Bland-Altman analysis was performed to determine the confidence limits of the volumes. RESULTS: On the unaffected side, the mean QMV was (1 944.45±323.77) cm3. The quadriceps CSA at the upper edge of the patella at 18, 15, and 12 cm was (80.80±12.16) cm2, (77.53±12.03) cm2, and (72.68±10.51) cm2, respectively. The coefficients of determination (R2), ascertained using curve estimation models, for the 3 positions were 0.819, 0.755, and 0.684 (P < 0.001), and the standard deviations of the volume estimated value (SEE) were 7.4%, 8.7%, and 9.8%. The fitting equations of the three horizontal positions were all good, but the fitting degree of CSA-18 was the highest. The Bland-Altman scatter plot showed that the arithmetic means of the QMV at 18, 15 and 12 cm from the upper edge of the patella 0.8 cm3, -1.1 cm3, and 0.9 cm3 and 95% limits of agreement (LoA) were (-268.8, 270.5), (-315.2, 313.1), and (-355.7, 357.5), respectively. The estimated QMV was in good agreement with the measured value. The difference between the estimated CSA-18 and measured values was the smallest. The results on the affected side were consistent. CONCLUSION: The correlation between QMV and CSA in the young men with the upper edge of patella as baseline was reliable and consistent. Among them, CSA-18 had the highest correlation with the QMV. However, different observation sites could be selected for different injuries of the quadriceps.

ac4C acetylation of RUNX2 catalyzed by NAT10 spurs osteogenesis of BMSCs and prevents ovariectomy-induced bone loss.

N-acetyltransferase 10 (NAT10) is the key enzyme for N4-acetylcytidine (ac4C) modification of mRNA, which participates in various cellular processes and is related to many diseases. Here, we explore the relationships among osteoblast differentiation, NAT10, and ac4C, and we found that NAT0 expression and the ac4C level of total RNA were decreased in the bone tissues of bilateral ovariectomized (OVX) mice and osteoporosis patients. Adenoviruses overexpressing NAT10 reversed bone loss, and Remodelin, an NAT10 inhibitor, enhanced the loss of bone mass in OVX mice. Moreover, bone marrow-derived mesenchymal stem cells (BMSCs) with low-level ac4C modification formed fewer calcium nodules in vitro with NAT10 silencing, whereas BMSCs with high-level ac4C modification formed more calcium nodules with NAT10 overexpression. Moreover, we demonstrated that the ac4C level of runt-related transcription factor 2 (RUNX2) mRNA was increased after BMSCs were cultured in osteogenic medium (OM) and decreased after NAT10 silencing. The RUNX2 mRNA half-life and protein expression decreased after silencing NAT10 in BMSCs. Therefore, NAT10-based ac4C modification promotes the osteogenic differentiation of BMSCs by regulating the RUNX2 ac4C level. Because abnormal levels of NAT10 are probably one of the mechanisms responsible for osteoporosis, NAT10 is a new potential therapeutic target for this disease.

[Roles of periodontal pathogens in the pathogenesis of atherosclerosis].

Periodontitis is closely related to systemic health, especially cardiovascular disease. Periodontal pathogens from periodontal infection actively participate in the formation and development of coronary atherosclerosis. At present, accumulcted evidences show that periodontal pathogen infection is an independent risk factor for cardiovascular events, which promotes the deepening of atherosclerosis through a variety of immune inflammation and metabolism-related molecular mechanisms. The present article reviews multipal aspects of the correlation between periodontitis and periodontal pathogens and cardiovascular disease, and the mechanism of periodontal pathogens affecting the occurrence and development of atherosclerosis.

[Research progress in the interaction between Treponema denticola and microorganisms of subgingival plaque].

Treponema denticola (Td) is a gram-negative anaerobic bacterium closely related to the occurrence and development of periodontal disease and it accounts for a considerable proportion of mature plaque. As a later colonizer of the subgingival plaque biofilm, Td may have complex interactions with earlier and concurrent colonists including symbiotic relationship as while as synergistic or antagonistic effects under the regulation of quorum sensing molecules. Adhesin and coaggregation, mediated by a series of surface molecules, are the basis of the interaction. These interactions are ultimately manifested as gene expression changes in metabolism and virulence, in which are mainly metabolism changes with up- or down-regulation of multiple enzymes related to amino acid metabolism. This article reviews the related researches on the interaction between Td and microorganisms of subgingival plaque.

[Porphyromonas gingivalis lipopolysaccharide regulates macrophage polarization via triggering receptors expressed on myeloid cells-1].

Objective: To investigate the relationship between pattern recognition receptor triggering receptors expressed on myeloid cells-1 (TREM-1) and M1/M2 polarization in macrophages stimulated by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS), so as to explore the mechanism of TREM-1 in periodontitis. Methods: Human monocytic cell line THP-1 were induced to differentiate into macrophages by phorbol-12-myristate-13-acetate and stimulated by 0 (blank control group) and 1 µg/ml Pg-LPS (LPS group), respectively. LP17, the TREM-1 inhibitor (LPS+LP17 group) and its control peptide (LPS+control peptide group) with final concentration of 0.1 µg/ml were added at the same time. After 24 hours stimulation, the expression of TREM-1, M1 markers and related cytokines [CD86, tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß], M2 markers and related cytokines (CD206,IL-10) mRNA were detected by real-time quantitative-PCR (RT-qPCR), the level of TREM-1, CD86 and CD206 proteins were detected by Western blotting, and TNF-α, IL-1ß and IL-10 in the macrophage culture supernatant were detected by enzyme linked immunosorbent assay. Results: After 24 h of cell culture, the relative expressions of TREM-1 mRNA (1.40±0.14) and protein (3.85±0.24) in macrophages in the LPS group increased compared with the blank control group (1.01±0.18 and 1.00±0.05, respectively) (P<0.05). Meanwhile, the expression levels of M1 markers CD86 mRNA and protein [LPS group vs blank control group were (1.42±0.01 vs 1.00±0.09) and (1.55±0.07 vs 1.00±0.10), respectively] were up-regulated (P<0.01), and the expressions of mRNA and protein of M1 related cytokines TNF-α and IL-1 increased (P<0.05). After the addition of TREM-1 blocker LP17, the levels of mRNA and protein of TREM-1 showed no significant changes (P>0.05), while the levels of CD86 mRNA (0.96±0.00) and protein (1.36±0.02) decreased (P<0.05), and the levels of TNF-α and IL-1 further decreased (P<0.05). For M2 marker CD206 and related cytokine IL-10, CD206 mRNA (0.56±0.05) and protein (0.25±0.04) were significantly down-regulated (P<0.01) compared with the blank control group (1.02±0.25 and 1.00±0.10, respectively), and IL-10 mRNA was up-regulated compared with the blank control group (P<0.05), with no significant change in protein (P>0.05). After the addition of LP17, the expressions of CD206 and IL-10 mRNA in the LPS+LP17 group were further down-regulated compared with the LPS group (P<0.05), and there was no statistically significant difference between the two groups in protein level (P>0.05). Conclusions: TREM-1 and its downstream signaling pathway might be involved in M1 polarization of Pg-LPS-mediated macrophages, thus playing a pro-inflammatory role in the development of periodontitis. There is no obvious evidence that TREM-1 is involved in regulating M2 polarization of Pg-LPS-mediated macrophages.

Analysis of risk factors and prognosis of post-stroke pulmonary infection in integrated ICU.

OBJECTIVE: The incidence of SAP (stroke-associated pneumonia) is high in integrated ICU (Intensive Care Unit), and it might result in sepsis, which exacerbates the clinical outcome and increases mortality. It is necessary to investigate the epidemiological features of post-stroke infection and sepsis, identify the risk factors and analyze the prognosis. PATIENTS AND METHODS: We retrospectively analyzed the data of 329 patients with cerebral infarction or cerebral hemorrhage, from seven tertiary university hospitals in Suzhou, Jiangsu Province, between January 1, 2016, and December 31, 2016. Basic demographic and clinical data including common health evaluation, stroke severity, microbiological parameters, surgical interventions and treatments were recorded for the analysis. SAP was diagnosed according to the criteria and recommendation from American Heart Association (AHA). RESULTS: 188 (66.4%) patients suffered pneumonia, 124 patients were diagnosed as SAP. Compared with SAP, patients with non-SAP pulmonary infection had prolonged mechanical ventilation time, prolonged central venous catheter indwelling time, and higher incidence of sepsis (17.7% vs. 48.4%). 53 patients (18.7%) developed sepsis during hospitalization, whose mortality rate during hospitalization and the occurrence of neurologic dysfunction at 3 months were significantly increased (p<0.05). 130 positive results of sputum cultures were found. The detected pathogens were mainly gram-negative bacteria. The pathogenic detection rate of non-SAP patients with pulmonary infection was higher (78.1%). The in-hospital mortality was 16.3% and the related risk factors were higher NIHSS score at admission, lower GCS score at admission, pulmonary infection (especially non-SAP pulmonary infection) and sepsis during hospitalization. CONCLUSIONS: The incidence of pulmonary infection after stroke in the integrated ICU is high, and it is easy to be complicated with sepsis, prolonging the mechanical ventilation time, central venous catheter indwelling time and hospitalization time, and the prognosis of long-term neurological function is relatively poor. The definition of stroke-associated pneumonia has implications for the classification of clinical infections, the prediction of possible pathogenic pathogens, and the guidance of anti-infective treatment.

Postpartum bilateral sacral stress fracture without osteoporosis-a case report and literature review.

PURPOSE: Sacral stress fractures are rare complications which can arise during pregnancy or in the early postpartum period. We report a case and discuss the findings of a confirmed postpartum sacral stress fracture in a 39-year-old multiparous woman and review previous case reports in the literature of sacral stress fracture related to pregnancy. METHODS: A review of the literature was conducted to examine the main characteristics of sacral stress fractures related to pregnancy. The Ovid/Medline, Embase and Google Scholar databases were searched with the inclusion criteria: human studies, English language, intrapartum, postpartum (within 6 months of parturition), sacrum and stress fracture. Our exclusion criteria included pubic fractures, vertebral fractures and non-English articles. The search terms included "stress fracture", "postpartum", "pregnancy", "atraumatic" and the wildcard "sacr*". Thirty-four cases were found and summarised in Table 2. RESULTS: A total of 65% of patients had onset of symptoms postpartum. Most patients did not have risk factors for sacral stress fractures including macrosomia, excessive pregnancy weight gain, heparin exposure, rapid vaginal delivery or predisposition to accelerated osteoporosis. Lumbar radiculopathy can be a feature of sacral stress fracture and it is more common (17.6%) than reported in the literature (2%). MRI is the preferred imaging modality for its safety profile in pregnancy and high sensitivity. A total of 70% reported normal bone mineral density (BMD). The mainstay treatment for sacral stress fractures includes relative bed rest, analgesia and modified weight-bearing exercises. Most patients have favourable outcome with complete symptom resolution. CONCLUSION: Sacral stress fractures in the absence of osteoporosis are rare complications of pregnancy that can present with lumbar radiculopathy. Conservative management often produces good clinical outcomes.

[Network analysis and characteristics of keystone taxa in periodontitis].

Subgingival microorganisms can orchestrate the microbial community under the influence of environmental factors, thus causing the initiation and progression of periodontitis. Keystone taxa play an important role in the dynamic changes of microbial community. The co-occurrence network analysis may pave the way for screening periodontitis associated candidate keystone taxa in the periodontal microflora. These microorganisms, e.g. Porphyromonas gingivalis, might function via myriad of intermediary taxa or as the chokepoint community-remodeling drivers in response of environmental factors. Herein, we review and discuss the construction of microbial co-occurrence network, the way of screening and identifying keystone taxa using network analysis as well as the characteristic of candidate keystone taxa related to periodontitis for the purpose that keystone taxa and the role they played in dynamic succession of microflora could be well investigated.

[Initial implantation experience and short-term follow-up results of implanting leadless intracardiac transcatheter pacing system].

Objective: To explore the utility and safety of leadless intracardiac transcatheter pacing system. Methods: The study was a prospective observational study. Patients underwent Micra transcatheter pacing system in Beijing Anzhen hospital from December 2019 to January 2020 were enrolled. The baseline characteristics, platelet count, hemoglobin, anticoagulation and/or antiplatelet therapy, mean procedural time, average fluoroscopy time, number of deployment and electrical parameters (threshold, R-wave amplitude, impedance) were recorded. Ultrasonography of bilateral femoral and iliac veins was performed in all patients. Patients were followed including access site complication, adverse event and device evaluation at implant, hospital discharge, 1 and 3 months post-implant. R-wave≥5 mV, impedance between 400 and 1 500 Ω and threshold increase≤1.5 V than implant is considered a stable parameter. Femoral access site complications included hematoma, hemorrhage, pseudoaneurysm, and arteriovenous fistula. Adverse events included dislodgement, cardiac effusion/perforation and infection. Left ventricular end diastolic diameter and ejection fraction before and at 1 month after implant were reported. Results: Five patients were enrolled and pacemaker implantation was successful in all 5 patients. Patients were all males and the average age was (78.4±8.4) years. 2 patients received aspirin and clopidogrel therapy, 1 patient suffered from anemia and thrombocytopenia occurred in 1 patient. No stenosis, occlusion and vascular malformation of bilateral femoral and iliac veins was observed. The mean implant time was (39.6±1.7) minutes. The average fluoroscopy time was (9.2±1.3) minutes and the number of deployment was (1.40±0.55). Electrical parameters(threshold, R-Wave amplitude and impedance) were as follows: (0.40±0.10) V/0.24 ms, (10.80±3.72) mV and (822.00±162.23) Ω at implant; (0.45±0.07) V/0.24 ms, (13.04±2.41) mV, and (748.0±91.5) Ω at discharge, (0.40±0.06) V/0.24 ms, (14.26±4.11) mV, and (700.0±91.7) Ω at 1 month post-implant and (0.39±0.05) V/0.24 ms, 14.40±3.97 mV, and (682.0±96.0) Ω at 3 months post-implant, respectively. Threshold increase was ≤1.5 V compared to that during implantation, electrical parameters were acceptable and stable. There was no difference in LVEDD [(44.00±5.24) mm vs. (44.00±5.34) mm,P=1.000] and EF [(62.00±3.39)% vs. (62.20±3.56)%, P=0.861] before and 1 month post-implant. No incidence of access site complications, cardiac effusion/perforation, dislodgment or infections occurred during the 3 months. Conclusions: The leadless transcatheter pacemaker implantation performed in our study archived a high implant success rate and favorable safety profile as well as associated with low and stable pacing thresholds. The long-term safety and benefit of leadless pacemaker need to be evaluated in future clinical studies.