Fourier transform spectrometer based on high-repetition-rate mid-infrared supercontinuum sources for trace gas detection

We present a fast-scanning Fourier transform spectrometer (FTS) in combination with high-repetition-rate mid-infrared supercontinuum sources, covering a wavelength range of 2-10.5 µm. We demonstrate the performance of the spectrometer for trace gas detection and compare various detection methods: baseband detection with a single photodetector, baseband balanced detection, and synchronous demodulation at the repetition rate of the supercontinuum source. The FTS uses off-the-shelf optical components and provides a minimum spectral resolution of 750 MHz. It achieves a noise equivalent absorption sensitivity of ∼10^-6 cm^-1 Hz^-1/2 per spectral element, by using a 31.2 m multipass absorption cell.

MiR-376a-3p alleviates the development of glioma through negatively regulating KLF15

OBJECTIVE

The purpose of this study was to uncover the role of microRNA-376a-3p (miR-376a-3p) in mediating migratory and invasive capacities of glioma, as well as the underlying mechanism.

PATIENTS AND METHODS

MiR-376a-3p levels in 39 collected glioma tissues were detected. After collecting clinical data of included glioma patients, the relationship between miR-376a-3p level and clinical features of glioma was analyzed. Next, regulatory effects of miR-376a-3p on proliferative and metastatic capacities of U251 and T98-G cells were assessed. Downstream genes of miR-376a-3p were searched by bioinformatics approach. At last, the involvement of KLF15 in the development of glioma regulated by miR-376a-3p was explored.

RESULTS

It was found that miR-376a-3p was lowly expressed in glioma tissues. Low level of miR-376a-3p was linked to high metastasis rate and poor prognosis in glioma. Besides, overexpression of miR-376a-3p suppressed proliferative and metastatic capacities of glioma cells. KLF15, the downstream gene binding miR-376a-3p, was highly expressed in glioma, and displayed a negative correlation to miR-376a-3p. Notably, KLF15 was able to abolish the regulatory effects of miR-376a-3p on phenotypes of glioma cells.

CONCLUSIONS

MiR-376a-3p is related to lymphatic metastasis and distant metastasis of glioma, and alleviates metastasis of glioma by negatively regulating KLF15.

[Clinical effects of retrograde anterolateral thigh perforator flaps assisted with computed tomography angiography in repairing skin and soft tissue defects around the knee or in proximal lower leg]

Objective: To investigate the clinical effects of retrograde anterolateral thigh perforator flaps assisted with computed tomography angiography (CTA) in repairing skin and soft tissue defects around the knee or in proximal lower leg. Methods: A retrospective cohort study was conducted. From May 2015 to October 2019, 17 patients with skin and soft tissue defects around the knee or in proximal lower leg were admitted to the Department of Orthopedics of Jizhong Energy Xingtai Mig General Hospital, including 12 males and 5 females, aged 16-65 years, with an average age of 35 years. The areas of skin and soft tissue defects after debridement ranged from 6.0 cm×3.0 cm to 15.0 cm×9.0 cm. The retrograde anterolateral thigh perforator flaps were designed according to the origin and distribution of the perforating branches in flaps and the length of the vascular pedicle examined with CTA and the condition of the wound to repair the wounds. The areas of resected flaps ranged from 6.5 cm×3.5 cm to 15.5 cm×9.5 cm. The wounds in donor sites of flaps were sutured directly or covered with medium-thickness skin grafts from healthy upper leg. The sources of the perforating branches in flaps were recorded. The lateral circumflex femoral artery, its branches, and the relative length of the vascular pedicle were compared between preoperative CTA detection and intraoperative observation. The survivals of the flaps were observed. At the last follow-up, the effects of flaps in repairing wounds were evaluated according to evaluation standard of efficacy satisfaction; the motion ranges of flexion and extension of the knee joint were measured, and the knee joint function was evaluated according to the Hohl knee joint function evaluation standard; the sensory function in the flap area was evaluated according to the sensory function evaluation standard formulated by the British Medical Research Council; the wound healing and the occurrence of complication affecting motor function of limb of flap donor sites was observed. Data were statistically analyzed with paired sample t test. Results: The perforating branches in flaps originated from descending branches, oblique branches, and rectus femoris branches of lateral circumflex femoral artery in 7, 6, and 4 patients, respectively. The flaps with blood supply from descending branches, oblique branches, and rectus femoris branches of lateral circumflex femoral artery were type 1, 2, and 3 retrograde anterolateral thigh perforator flaps, respectively. The preoperative CTA examination of lateral circumflex femoral artery and its branches were consistent with those observed during operation. The relative lengths of vascular pedicles of type 1, 2, and 3 retrograde anterolateral thigh perforator flaps calculated after CTA examination were 0.32±0.13, 0.56±0.07, and 0.56±0.15, which were close to 0.35±0.12, 0.52±0.10, and 0.53±0.12 measured and calculated during operation, respectively (t=0.45, 0.80, 0.31, P>0.05). All flaps survived in 17 cases without vascular crisis. At the last follow-up, 16 patients were satisfied with effects of flaps in wound repair, with 1 patient feeling average about the effect; the flexion range of knee joint was 100-120°, and the extension range of knee joint was -2-0°; knee joint function was evaluated as excellent in 9 cases, good in 7 cases, and poor in 1 case; the sensory function of the flap area reached S₄ level in 2 cases, S₃ level in 8 cases, and S₂ level in 7 cases; the wounds in flap donor sites healed well; there was no adverse effect in motor function of limbs. Conclusions: Retrograde anterolateral thigh perforator flap is an effective method for repairing skin and soft tissue defects around the knee or in proximal lower leg. Preoperative CTA examination can fully show the anatomical characteristics of the branches of the lateral circumflex femoral artery and the perforating vessels of each branch, which can guide preoperative flap design and operation, thus shortening operation time and improving flap survival rate, with good clinical effects.

Quantitative proteomics analysis reveals the response mechanism of peanut (Arachis hypogaea L.) to imbibitional chilling stress

Imbibitional chilling stress inhibits normal seed germination and seedling establishment and leads to large losses in peanut production. This is a major limiting factor when sowing peanut earlier and further north. To reveal the response mechanism of peanut to imbibitional chilling stress, a Tandem Mass Tag (TMT)-based quantitative proteomics analysis was conducted to identify differentially accumulated proteins (DAPs) under imbibitional chilling stress. Hormone profiling and transcriptional analysis were performed to confirm the proteomics data. Further seed priming analysis with exogenous cytokinins was conducted to validate the role of cytokinins in alleviating imbibitional chilling injury. A total of 5029 proteins were identified and quantified in all of the experimental groups. Among these, 104 proteins were DAPs as compared with the control. Enrichment analysis revealed that these DAPs were significant in various molecular functional and biological processes, especially for biosynthesis and metabolism of plant hormones. Hormone profiling and transcription analysis suggested that the reduced abundance of cytokinin oxidase may be caused by down-regulation of gene expression of the corresponding genes and leads to an elevated content of cytokinins under chilling stress. Seed priming analysis suggested that exogenous application of cytokinins may alleviate injury caused by imbibitional chilling. Our study provides a comprehensive proteomics analysis of peanut under imbibitional chilling stress, suggesting the role of plant hormones in the response mechanism. The results provide a better understanding of the imbibitional chilling stress response mechanism in peanut that will aid in peanut production.

[A nested case-control study on relationship of traditional and combined lipid metabolism indexes with incidence of diabetes]

Objective: To explore the relationship between lipid indicators and the incidence of diabetes, and to compare the diabetes prediction and identification power of traditional lipid combined lipid indicators, in order to explore the best alternative indicators for identifying and predicting diabetes. Methods: Based on the Jinchang cohort, a nested case-control study was conducted in 1 025 new cases of diabetes after excluding patients with malignant tumor and related endocrine, circulatory system disease, then an age (±2 years), gender matched 1∶1 control group of 1 025 cases was set to analyze the relationship between the incidence of diabetes and lipid parameters. Results: Among the traditional lipid parameters, the fourth quartile of TG, TC, and LDL-C indicated higher risks of developing diabetes, which was 14.00 times (95%CI: 9.73-20.15), 2.15 times (95%CI: 1.65-2.79) and 1.66 times (95%CI: 1.29-2.14) than that of the first quartile, respectively. The risk of developing diabetes indicated by the fourth quartile of HDL-C was 0.21 times than that indicated by the first quartile (95%CI: 0.15-0.28). In the combined lipid parameters, the fourth quartile of TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C indicated higher risks of developing diabetes, which was 14.86 times (95%CI: 10.35-21.34), 8.12 times (95%CI: 5.94-11.01), 5.85 times (95%CI:4.34-7.88) and 5.20 times (95%CI: 3.85-7.03) than that indicated by the first quartile, respectively. The areas under the ROC curve of TG, TC, HDL-C, LDL-C, TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C were 0.76 (95%CI: 0.74-0.78), 0.59 (95%CI: 0.57-0.61), 0.67 (95%CI: 0.65-0.69), 0.57 (95%CI: 0.55-0.59), 0.77 (95%CI: 0.75-0.78), 0.73 (95%CI: 0.71-0.75), 0.69 (95%CI: 0.67-0.71) and 0.66 (95%CI: 0.64-0.68), respectively. The optimal diabetes predicting point cuts of TG, TC, HDL-C, LDL-C, TG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C were 1.40, 4.70, 1.28, 3.25, 1.17, 3.43, 2.46, and 3.58 mmol/L, respectively. Conclusions: Lipid metabolic disorder is a risk factor for diabetes. TG and TG/HDL-C are the good lipid metabolism indicators for the prediction of diabetic.

[Relationship of body mass index and blood pressure with diabetes: a nested case-control study]

Objective: To explore the relationship of body mass index and blood pressure with the incidence of diabetes in Jinchang cohort. Methods: We designed a nested case-control study, a total of 29 572 workers who had no history of diabetes in baseline survey in Jinchang cohort were selected as the study cohort from June 2011 to December 2013. After 2 year follow-up, 1 021 workers with first diagnosed diabetes were selected as the case group, after 1∶1 matching according to the same gender and age ±2 years among those without diabetes, circulatory system, or endocrine system diseases during the same follow-up period, 1 021 controls was selected and 2 042 subjects were finally included. We used multivariate conditional logistic regression model, additive interaction model and multiplicative interaction model to explore the relationship of body mass index and blood pressure with the incidence of diabetes. Results: After adjusting for factors such as occupation, alcohol use, family history of diabetes, hyperuricemia, hypercholesterolemia, hypertriglyceridemia, low-HDL cholesterolemia and high-LDL cholesterolemia, multivariate conditional logistic regression analysis showed that the risk of diabetes increased with body mass index and blood pressure. Hypertension and overweight/obesity had a multiplicative interaction on the incidence of diabetes. The risks of diabetes in men and women with hypertension and overweight/obese were 2.04 times (95%CI: 1.54-2.69) and 3.88 times (95%CI: 2.55-5.91) higher than those in men and women with normal body weight and blood pressure, respectively. In the combination of BMI and blood pressure, obese individuals with SBP≥160 mmHg were 4.57 times (95%CI: 2.50-8.34) more likely to have diabetes than those with normal BMI and SBP, obese individuals with DBP≥90 mmHg were 3.40 times (95%CI: 2.19-5.28) more likely to have diabetes than those with normal BMI and DBP. Conclusions: Overweight/obesity and hypertension can increase the risk of diabetes. Health education about body weight and blood pressure controls should be strengthened to reduce the risk of diabetes.

Precise correction of Duchenne muscular dystrophy exon deletion mutations by base and prime editing

Duchenne muscular dystrophy (DMD) is a fatal muscle disease caused by the lack of dystrophin, which maintains muscle membrane integrity. We used an adenine base editor (ABE) to modify splice donor sites of the dystrophin gene, causing skipping of a common DMD deletion mutation of exon 51 (∆Ex51) in cardiomyocytes derived from human induced pluripotent stem cells, restoring dystrophin expression. Prime editing was also capable of reframing the dystrophin open reading frame in these cardiomyocytes. Intramuscular injection of ∆Ex51 mice with adeno-associated virus serotype-9 encoding ABE components as a split-intein trans-splicing system allowed gene editing and disease correction in vivo. Our findings demonstrate the effectiveness of nucleotide editing for the correction of diverse DMD mutations with minimal modification of the genome, although improved delivery methods will be required before these strategies can be used to sufficiently edit the genome in patients with DMD.

MiR-200c promotes proliferation of papillary thyroid cancer cells via Wnt/β-catenin signaling pathway

OBJECTIVE

To investigate the potential effects of miR-200c on proliferation and apoptosis of papillary thyroid cancer (PTC) cells.

MATERIALS AND METHODS

Micro ribonucleic acid-200c (miR-200c) inhibitor was transfected to down-regulate miR-200c expression. Cell counting kit-8 (CCK-8), colony formation experiment, and flow cytometry were used to detect the effects of miR-200c knockdown on proliferation and apoptosis of Butylated Hydroxytoluene 101 (BHT101) cells. The dual-luciferase reporter gene assay was conducted to detect whether miR-200c directly binds to the target gene. After knocking down miR-200c, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting analysis were performed to detect changes of target genes regarding messenger RNA (mRNA) and protein. Western blotting analysis was also adopted to detect gene expression of Wnt/β-catenin signaling pathway-related proteins.

RESULTS

Compared with those in control group, the proliferation and clone formation ability of BHT101 cells in miR-200c knockdown group were significantly inhibited (p<0.05), while the apoptosis rate increased markedly (p<0.05). Dachshund Family Transcription Factor 1 (DACH1) was the direct target gene of miR-200c. After miR-200c knockdown, the expression levels of Wnt/β-catenin signaling pathway members (including c-Myc, β catenin and cyclin D1) all decreased.

CONCLUSIONS

MiR-200c is a tumor suppressor miRNA, which promotes proliferation of PTC cells and activates Wnt/β-catenin signaling pathway by directly regulating the corresponding target protein, DACH1.

Prx II reduces oxidative stress and cell senescence in chondrocytes by activating the p16-CDK4/6-pRb-E2F signaling pathway

OBJECTIVE

Osteoarthritis (OA) is a common clinical degenerative disease and has a high incidence in the elderly. The purpose of this study was to explore the anti-oxidative stress and anti-aging effects of Peroxiredoxin II (Prx II) on articular chondrocytes, as well as its molecular mechanism.

MATERIALS AND METHODS

Articular cartilage tissues and culture human articular chondrocytes were selected. By constructing Prx II overexpressing lentivirus, the effects of Prx II on oxidative stress and cell senescence in chondrocytes were studied. Besides, the p16 overexpression lentivirus was constructed to investigate the effect of Prx II on the p16-CDK4/6-pRb-E2F signaling pathway (p16 signaling pathway).

RESULTS

Articular cartilage tissues in patients with OA and IL-1β-induced chondrocytes expressed lower Prx II and had higher p16 signaling pathway activity. The overexpression of Prx II significantly increased the expression of SOD1 and SOD2 and decreased the expression of β-gal and P53/P21, indicating that Prx II can reduce the oxidative stress and senescence level of chondrocytes. Moreover, the overexpression of Prx II increased the expression of p16 signaling pathway-related molecules and the activation of the p16 signaling pathway attenuated the anti-oxidative stress and anti-aging effects of Prx II.

CONCLUSIONS

Prx II can inhibit the p16 signaling pathway in chondrocytes to reduce the level of aging in chondrocytes, thereby reducing the level of oxidative stress in chondrocytes, and ultimately inhibiting the progression of OA.

[The prognostic value of myoglobin difference in sepsis related chronic critical illness]

Objective: To investigate the predictive value of myoglobin (Mb) for the prognosis of sepsis related chronic critical illness (CCI). Methods: Retrospective study was conducted on septic patients with the length of ICU stay equal or greater than 14 days, and sepsis-related organ failure assessment (SOFA) score equal or greater than 2 on the 14th day in ICU in the First Department of Critical Care Medicine at the First Affiliated Hospital of Sun Yat-sen University from January 2017 to March 2020. Patients' clinical and laboratory data were collected on the 1st and 14th day in ICU. The survival on day 28 in ICU was recorded. According to the myoglobin levels on day 1 and day 14, all subjects were divided into myoglobin elevation group and decline group. Kaplan-Meier survival curve was used to compare the cumulative survival rate at day 28. Cox regression analysis was used to analyze the independent risk factors of mortality. Receiver operating characteristic (ROC) curve was used to analyze the prognostic value of myoglobin. Results: A total of 131 patients with sepsis related CCI were recruited, including 58 patients in the elevation group and 73 in the decline group. The Mb level in elevation group on day 1 was significantly lower than that in decline group [172.40(59.99, 430.53) μg/L vs. 413.60(184.40, 1 328.50) μg/L, Z=3.749, P=0.000], and the Mb level on day 14 was the opposite change in two groups [483.65(230.38, 1 471.75)μg/L in elevation group vs. 132.20(76.86, 274.35)μg/L in decline group, Z=5.595, P=0.000]. Kaplan-Meier survival curve analysis showed that the 28-day cumulative survival rate of the elevation group was significantly lower than that of decline group (χ²=7.051, P=0.008). Cox ratio regression analysis suggested that elevated myoglobin was an independent risk factor for 28-day mortality in septic patients with CCI (OR=2.534, 95%CI 1.212-5.295, P=0.013). ROC curve analysis suggested that the sensitivity of myoglobin elevation in predicting mortality related to CCI within 28 days was 64.5%, and the specificity was 32.0% with area under the curve(AUC) 0.661(95%CI 0.550-0.773,P=0.007) and Jorden Index was 0.325. Conclusion: Elevated myoglobin, an independent risk factor for mortality within 28 days in ICU, can predict the prognosis of sepsis related chronic critical illness.

[Prospective cohort study of relationship of triglyceride, fasting blood-glucose and triglyceride glucose product index with risk of hypertension]

Objective: To investigate the relationship of triglyceride (TG), fasting blood glucose (FPG) and triglyceride glucose product index (TyG) with the incidence of hypertension, and provide basic data for the prevention and treatment of hypertension in the population. Methods: A total of 23 581 individuals who met the research criteria in Jinchang cohort were selected as the research subjects, the Cox proportional hazard model was used to analyze the relationship of TG, FPG, and TyG with the risk of hypertension. A stratified analysis was conducted by sex. Results: After adjusting for confounding factors, compared with the normal TG group, the HR(95%CI) of the elevated TG margin group and the elevated group were 1.16 (1.01-1.34) and 1.49 (1.30-1.70), respectively in the total population. Among men, they were 1.13 (1.01-1.27) and 1.17 (1.06-1.30), and among women, they were 1.05 (0.88-1.26) and 1.06 (0.88-1.28). Compared with the normal FPG group, the HR (95%CI) of the FPG-impaired group were 1.29 (1.13-1.48) in the total population, 1.26 (1.08-1.48) in men and 1.59 (1.14-2.21) in women. Taking the lowest quartile array as a reference, the HR (95%CI) of the highest quartile array of TyG was 1.73 (1.45-2.07) in the total population, 1.32 (1.14-1.53) in men and 1.87 (1.37-2.54) in women. TG, FPG had a nonlinear dose-response relationship with the risk of hypertension, while TyG had a linear correlation with the risk of hypertension. Conclusions: Higher TG, FPG, and TyG levels are independent risk factors for the incidence of hypertension. People with higher TG, FPG and TyG are at high risk for hypertension, to which close attention should be paid in the prevention and treatment of hypertension.

Location and Vascular Classification of 188 parathyroid glands in New Zealand White Rabbits

ABSTRACT The function and protection of the parathyroid glands are increasingly popular research topics. New Zealand white rabbits are the most commonly used animal model of parathyroid ischemia. However, information on the vasculature of their parathyroid glands is limited. We used 94 healthy New Zealand white rabbits, 3-4 months of age and 2-3kg in weight, for exploration of the parathyroid glands, which were stained using hematoxylin and eosin (HE) after removal. The following types were classified according to the relationship between the position of the inferior parathyroid gland and the thyroid: Type A, Close Type, Type B, and Distant Type. There were 188 cases, 4 where the inferior parathyroid glands were located near the dorsal side of thyroid (2.13%), 8 where the inferior parathyroid glands were located superior to the upper pole of the thyroid (4.26%), 20 where the inferior parathyroid glands were located parallel to the thyroid (10.64%), and 155 cases where the inferior parathyroid glands were located inferior to the lower pole of thyroid (82.45%). Identifying the location and classifying the vasculature of the parathyroid glands in New Zealand white rabbits will provide an anatomical model to assist in future research.

[Efficacy and safety of catheter ablation in patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma]

Objective: To evaluate the safety and efficacy of catheter ablation in patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma. Methods: Nine patients with new onset atrial arrhythmia and a prior history of left atrial myxoma, who received surgical myxoma excision and catheter ablation between September 2014 and November 2019, were included in the present study. Baseline characteristics, procedural parameters during catheter ablation, severe perioperative adverse events, recurrence rate of arrhythmia and clinical prognosis were analyzed. Kaplan Meier survival analysis was used to define the maintenance rate of sinus rhythm after catheter ablation in this patient cohort. Results: Nine patients were included. The average age was (55.8 ± 9.1) years old (3 male), there were 3 patients (3/9) with paroxysmal atrial fibrillation (PAF) and 6 patients (6/9) with atrial flutter or atrial tachycardia (AFL or AT). Ablation was successful in all patients, there were no perioperative complications such as stroke, pericardial effusion, cardiac tamponade, vascular complications or massive hemorrhage. During a mean follow-up time of 40.0 (27.5, 55.5) months, sinus rhythm was maintained in six patients (6/9) after the initial catheter ablation. The overall sinus rhythm maintenance rate was 2/3. In addition, 1 out of the 3 AF patients (1/3) developed recurrence of AF at 3 month after ablation, and 2 out of the 6 AFL or AT patients (2/6) developed late recurrence of AF or AFL (19 months and 29 months after ablation), two out of three patients with recurrent AFs or AFL received repeated catheter ablation and one patient remained sinus rhythm post repeat ablation. Meanwhile, there was no recurrence of atrial myxoma, no death, stroke, acute myocardial infarction and other events during the entire follow-up period. Conclusions: Catheter ablation is a safe and feasible therapeutic option for patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma.

Effects of lncRNA SNHG20 on proliferation and apoptosis of non-small cell lung cancer cells through Wnt/β-catenin signaling pathway

OBJECTIVE

To investigate the influence of long non-coding ribonucleic acid (lncRNA) small nucleolar host gene 20 (SNHG20) on the proliferation and apoptosis of non-small cell lung cancer (NSCLC) cells through the Wnt/β-catenin signaling pathway.

PATIENTS AND METHODS

The human NSCLC cells were cultured and lncRNA SNHG20 was inhibited using si-SNHG20 and overexpressed using SNHG20-OE. Then, flow cytometry was used to detect the apoptotic rate. The targets of lncRNA SNHG20 were detected via dual-luciferase reporter gene assay, and the changes in the protein level were detected via Western blotting.

RESULTS

LncRNA SNHG20 was highly expressed in the cancer tissues and serum of patients with NSCLC. LncRNA SNHG20 could promote the proliferation and inhibit the apoptosis of NSCLC cells. LncRNA SNHG20 could bind to micro RNA (miR)-197 in a targeted manner. Besides, nuclear translocation of β-catenin was significantly enhanced after transfection of miR-197. After the down-regulation of miR-197 by small interfering RNA (siRNA), the key molecules TCF and LEF1 of the Wnt/β-catenin pathway were significantly down-regulated.

CONCLUSIONS

LncRNA SNHG20 promotes the proliferation and inhibits the apoptosis of NSCLC cells by targeting miR-197 through the Wnt/β-catenin signaling pathway.

The Impact of Frailty on COVID-19 Outcomes: A Systematic Review and Meta-analysis of 16 Cohort Studies

BACKGROUND

Frail patients are increasingly vulnerable to stress, which is mainly manifested by a reduced physiologic reserve in metabolic and immune systems and neuromuscular system. Several studies found a significant association of frailty with COVID-19 severity to support the evidence for the application of frailty assessment. However, there were contradictory results in other studies. Thus we conducted a systematic review and meta-analysis to synthesize the current studies to investigate impact of frailty on COVID-19 outcomes and provide evidence-based decisions in clinical practice.

OBJECTIVE

We aimed to synthesize the current studies to investigate impact of frailty on COVID-19 outcomes and provide evidence-based decisions in clinical practice.

DESIGN

A systematic review and Meta-analysis of 16 cohort studies.

PARTICIPANTS

Patients with COVID-19.

METHODS

A systematic retrieving for potential literature was conducted in several public electronic databases, including Medline(OvidSP), EMBASE, Pubmed and Chinese databases(China National Knowledge Infrastructure,Wanfang and Weipu) on August 1, 2020.The literature research was updated on October 26, 2020. Newcastle Ottawa Scale for cohort studies was used for quality assessment. RevMan (Version 5.3) and Stata 14.0 were used to synthesize the pooled effects.

RESULTS

According to the predefined inclusion and exclusion criteria, sixteen studies of 4324 patients were included in the final analysis. Frailty was significantly associated with increased risk of all-cause mortality among patients with COVID-19, with pooled adjusted odds ratios of 1.81 (95% confidence intervals:1.48,2.21, I2=87.0%, P<0.001). The result was consistent in stratified analysis to according to age, patient source, definitions of frailty, study quality, and adjustment method. Frailty was significant associated with an increased risk of COVID-19 severity, admission to intensive care unit, application of invasive mechanical ventilation, long-length stay.

CONCLUSIONS

In this meta-analysis, we found frailty was significantly associated with an increased risk of clinical adverse events (all- cause mortality, COVID-19 severity, admission to the intensive care unit, application of invasive mechanical ventilation, long-length stay). Given the epidemic of COVID-19 and shortage of medical resources, paying more attention to screening frailty would contribute to disease management and resource allocation among patients with COVID-19.

Role of CACNA1C variants in Brugada syndrome: clinical aspects and genetic testing strategies

Background

Inconsistent data support the role of CACNA1C as a disease-causing gene responsible for Brugada syndrome (BrS). As of today, the only gene consistently linked with BrS is SCN5A. Several CACNA1c genetic variants have been reported in association wirh BrS; however, due to the limited evidence, CACNA1C is not suggested for routine genetic screening for BrS.

Purpose

In this study, we carried out a systematic screening of CACNA1C gene, including a functional evaluation of the identified variants, in order to determine the yield of screening in a large series of BrS probands and to address the hypothesis that an appropriate clinical selection of patients would substantially improve the yield of genetic testing.

Methods and results

Overall 564 consecutive patients, referred for BrS genetic testing, were sequenced for CACNA1C gene. Patients were divided in two groups: discovery cohort (n=200 patients) and confirmation cohort (n=363 patients). Furthermore, analysis of the clinical phenotypes of a matched SCN5A positive BrS cohort (n=146) was included for phenotype characterization.

In the discovery cohort we identified 11 different genetic variants of whom 2 (18%) were considered as potentially causative based on ACMG guidelines. However, a large proportion (81%) was classified as variants of unknown significance (VUS). Functional evaluation of the identified variants, including pathogenic and VUS, was assessed by patch-clamp and immunofluorescence studies. Re-evaluation of the variants, including functional studies results, indicated an increase of pathogenic or likely pathogenic variants (81%) getting a yield of screening of 5% in the discovery cohort. Results from the confirmation cohort confirmed a low rate of CACNA1C carriers with a yield of screening of 2.2%.

Analysing the clinical phenotype of all CACNA1C carriers showed a significantly shorter QTc [371 ms ± 16 ms vs. 399±18 ms; p=0.000004]. Furthermore, the prevalence of CACNA1C variants was highest (12.9%) among patients with a QTc in the lowest quartile (QTc &lt;390 ms). ROC curve showed an AUC of 0.91 for QTc a cut-off of 385 ms, suggesting a high predictive accuracy.

Conclusion

We confirmed that CACNA1C variants are not a common cause of BrS, with a yield of screening of 2–5%. However, pathogenic variants are more frequent (12.5%) in patients with a shorter QTc, suggesting a genetic testing strategy in this subgroup of BrS patients. Furthermore, our data highlights the impact of robust functional studies to improve variant classification and reduce uncertainties.

Funding Acknowledgement

Type of funding source: None

Multi-scale mechanical investigation of articular cartilage suffered progressive pseudorheumatoid dysplasia

BACKGROUND

Progressive pseudorheumatoid dysplasia is a rare skeletal dysplasia mainly caused by abnormal autosomal recessive inheritance. Although the main function of cartilage is mechanical support and the characteristics of this disease is the degradation of AC, previous studies on it had been mainly focused on clinical and genetic aspects and the mechanical behavior of the cartilage affected by PPRD is still ambiguous. In this study, we investigate the mechanics and structure of the cartilage suffered disease at multi-scale, from individual chondrocytes to the bulk-scale tissue.

METHODS

Depth-sensing indenter were employed to investigate the mechanics of cartilage; we performed atomic force microscope nanoindentation to investigate the cell mechanics and scanning electron microscopy were used to explore the structure feature and chemical composition.

FINDINGS

The elastic modulus of chondrocytes harvested from cartilage suffered from progressive pseudorheumatoid dysplasia is significantly higher than from normal cartilage, same trend were also found in tissue level. Moreover, denser collagen meshwork and matrix calcification were also observed.

INTERPRETATION

The elastic modulus of cartilage should closely related to its denser structure and the calcification, and may potentially be an indicator for clinical diagnosis. The stiffening of chondrocytes during PPRD progression should play a rather important role in its pathogenesis.

[The thromboembolism risk of low-risk atrial fibrillation patients with different clinical characteristics]

Objective: This study explored the thromboembolism risk of low-risk atrial fibrillation (AF) patients (CHA₂DS₂-VASc score of 0 or 1 for male and 1 or 2 for female) with different clinical characteristics to provide the basis for anticoagulation decision-making in these patients. Methods: We prospectively enrolled consecutive 2 862 nonvalvular low-risk AF patients between August 2011 to December 2018 in China-AF (China Atrial Fibrillation Registry) Study, their CHA₂DS₂-VASc score was 0 or 1 for male and 1 or 2 for female. According to their age, sex, presence or absence of hypertension, diabetes mellitus, congestive heart failure, and vascular disease at the time of enrolling, patients were divided into CHA₂DS₂-VASc score 0 score group, 1 score group, and 2 score group. Patients were followed up every 6 months by outpatient clinic visit or telephone interview. The outcome was a thromboembolic event, including ischemic stroke and systemic embolism. Univariate Cox regression analysis was used to compare the thromboembolism risk between the patients with different risk factors and CHA₂DS₂-VASc score 0 group. Results: A total of 2 862 low-risk atrial fibrillation patients were enrolled in this study. 915 patients (32.0%) were female, and age was (55.0±10.7) years old. There were 933 patients (32.6%) in CHA₂DS₂-VASc score 0 group, 1 401 patients (49.0%) in score 1 group and 528 patients (18.5%) in score 2 group. During follow-up (median 1.5 years, 5 811.82 person-years), 33 cases of thromboembolic events were recorded, the annual rate of thromboembolism was 0.57% (95%CI 0.40%~0.80%). The number of thromboembolic events in patients with CHA₂DS₂-VASc score 0, 1 and 2 were 8, 11 and 14, respectively, and the annual thromboembolism event rates were 0.40% (95%CI 0.20%-0.81%), 0.39% (95%CI 0.22%-0.71%) and 1.34% (95%CI 0.80%-2.27%), respectively. The risk of thromboembolism of CHA₂DS₂-VASc score 2 group (HR=3.53, 95%CI 1.48-8.44; P=0.005), especially female patients aged 65-74 years in CHA₂DS₂-VASc score 2 group (HR=2.67, 95%CI 1.63-4.38; P<0.000) was significantly higher than that in patients of CHA₂DS₂-VASc score 0 group. Conclusion: Low-Risk Atrial Fibrillation patients with CHA₂DS₂-VASc score 2, especially female patients aged 65-74 years old with CHA₂DS₂-VASc score 2 are at higher risk of thromboembolism in low-risk AF patients. For such patients, intensified oral anticoagulant therapy might be helpful to reduce the risk of thrombolism.