The Relationship between Dietary Copper intake and Telomere Length in Hypertension

BACKGROUND

More indications proved that diet might be involved in the telomere length, a marker of biological aging and chronic diseases. Copper is widely viewed as one of the essential elements in the diet. Therefore, this study aimed to evaluate the relationship between telomere length and dietary copper intake in hypertension and provide a basis for guiding dietary copper intake in patients with hypertension.

METHODS

The data was collected from the National Health and Nutrition Examination Survey (NHANES) in 1999-2000 and 2001-2002. The relevance between telomere length and dietary copper intake in hypertension is assessed using a multivariable linear regression model.

RESULTS

We gathered 1,867 participants with hypertension with assessed telomere length and dietary copper intake. We found that one unit increasing log-transformed dietary copper intake in hypertension was significantly associated with longer telomere length base pair (bp) (β = 112.20, 95% confidence interval [CI]: 5.48, 218.92), after controlling for covariates, including age, sex, ethnicity, body mass index (BMI), physical activity, and taking medication for hypertension. For the age group, we found that one unit increasing log-transformed dietary copper in hypertension was associated with longer telomere length (β = 237.95, 95% CI: 114.39, 361.51) in the age group >45 years. The grouping was based on whether the participants take medication for hypertension. We found that one unit increasing log-transformed dietary copper in hypertension was associated with longer telomere length (β = 116.47, 95% CI: 0.72, 232.21) in the group that takes medication for hypertension.

CONCLUSIONS

This study demonstrates that dietary copper intake was associated with longer telomere length in patients with hypertension, which provides evidence for guiding dietary copper intake in patients with hypertension. However, further studies are needed to evaluate the effect of copper supplementation on telomere length in patients with hypertension in well-designed random control studies and prospective studies.

Mechanical Stability and Proteolytic Activity of Resin-dentin Bonds Using the Cross-linked Dry Bonding Technique

OBJECTIVE

To evaluate the mechanical stability and the proteolytic activity of bonds created by a two-step, etch-and-rinse adhesive applied to cross-linked and air-dried etched dentin.

METHODS

Flat dentin surfaces were produced in 64 extracted sound human molars. The dentin was etched with 35% phosphoric acid for 15 seconds, and then the teeth were divided into groups according to the cross-linking solution applied on the etched dentin. Group 1: 5% grape seed extract (GSE), Group 2: 5% glutaraldehyde, Group 3: Gluma Desensitizer, or Group 4: deionized water (control). Solutions were applied for 60 seconds, followed by rinse and blot drying. Then, the teeth were separated into two subgroups where the etched dentin was kept moist or air-dried. The adhesive was applied followed by a composite resin buildup. After 24 hours, the teeth were cut into beams (0.81 mm2) that were tested for microtensile strength immediately or after 12 months of aging in a 37°C saliva-like buffer. Additional teeth (n=32) were bonded as described and cut into 0.5-mm-thick slabs. The slabs were prepared for nanoleakage (scanning electron microscopy) and in situ zymography (EnzChek Protease Assay Kit). Bond strength data were submitted to ANOVA and Tukey tests (α=0.05).

RESULTS

Significant reduction in immediate bond strength (ca 65%) and increase in proteolytic activity was seen when the etched dentin was air dried without previous cross-linking biomodification. Conversely, bond strengths did not differ from those produced on wet dentin when collagen was cross-linked before air drying, irrespective of the solution applied. For both moist and air-dried etched dentin, collagen cross-linking resulted in mechanically stable bonds and reduced proteolytic activity after 12 months of storage.

CONCLUSION

Bonds produced by the application of a two-step, etch-and-rinse adhesive to cross-linked, air-dried, etched dentin were mechanically stable and revealed reduced proteolytic activity after 1 year of aging.

[Insular infraorbital neurovascular pedicle labial salivary gland transplantation for severe dry eye: a case report]

A 52-year-old male presented to Beijing Tongren Hospital with a 5-year history of bilateral dry eyes. He had been diagnosed with Steven-Johnson syndrome due to allergy to cold medication. On examination, the Schirmer I test value was 0 mm, the tear break-up time was 0 s, and corneal fluorescein staining showed corneal epithelial erosion with partial fusion in both eyes. The clinical diagnosis was dry eyes (severe) and Steven-Johnson syndrome. No significant effect was observed after use of artificial tears and anti-inflammatory eye drops and tear punctal embolization. Then an insular infraorbital neurovascular pedicle labial salivary gland transplantation was performed in the right eye. During the 1-year postoperative follow-up, the symptoms and signs were significantly improved in the operated eye, and the surgical results were satisfactory. (Chin J Ophthalmol, 2021, 57: 946-948).

[Clinical follow-up study of myelin oligodendrocyte glycoprotein antibody-associated disease in children]

Objective: To summarize the clinical characteristics of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and compare the differences in efficacy of different disease-modifying drugs. Methods: An ambispective cohort study was conducted in 42 children diagnosed with MOGAD at Department of Pediatrics, Peking University First Hospital from January 2012 to March 2021 and conducted long-term follow-up to analyze clinical phenotypes and compare the efficacy of different disease-modifying drugs such as rituximab, mycophenolate mofetil and azathioprine. Kruskal-Wallis H test was used to compare the annual relapse rate of disease-modifying drugs at different times, expanded disability status scale (EDSS) score at the last follow-up, and Wilcoxon rank test was used to compare the annual relapse rate before and after modified disease therapy. The Log-rank (Mantel-Cox) survival curve was used to compare the relapse rate of different disease-modifying drugs. Results: Of the 42 cases, 22 were male and 20 were female, with the age at disease onset of 5.96 (2.33-12.90) years. The disease duration was 4.46 (1.25-13.00) years at the last follow-up with 161 clinical acute attacks. Acute disseminated encephalomyelitis (ADEM) was the most common phenotype of first attack and all attacks during disease course ((60% (25/42) for first attack, 38% (61/161) for all attacks). The most common clinical syndrome was neuromyelitis optica spectrum disorders (NMOSD) (50%, 21/42). Of the 42 children, 5 (12%) showed encephalitis and 6 (14%) combined with anti-N-methyl-D-aspartate receptor (NMDAR) antibody overlap syndrome. The most commonly involved areas of brain magnetic resonance imaging (MRI) were subcortical white matter (71%, 88/124), cortex (26%, 32/124) and periventricular white matter (25%, 32/124). Spinal cord MRI was most frequently involved in cervical (70%, 16/23) and thoracic (61%, 14/23) medulla, and 43% (10/23) longitudinally extensive transeverse myelitis. Disease-modifying drugs were used in 34 patients. The annual relapse rate after treatment with rituximab, mycophenolate mofetil and azathioprine decreased (all P<0.05) and there was no statistically significant difference in the annual relapse proportion among the groups (P=0.307). Conclusions: The most common clinical attack of first and all of MOGAD in children is ADEM, and the most common clinical syndrome is NMOSD. Rituximab, mycophenolate mofetil and azathioprine can reduce the annual relapse rate, but it is not clear effect of which treatment is better.

Role of quantitative energy spectrum CT parameters in differentiating thymic epithelial tumours and thymic cysts

AIM

To explore the utility of multiple energy spectrum computed tomography (CT) parameters in distinguishing thymic epithelial tumours (TETs) from thymic cysts among lesions <5 cm in diameter.

MATERIALS AND METHODS

Data pertaining to 56 patients with TETs and thymic cysts <5 cm in diameter were assessed retrospectively. All patients underwent surgical resection and the diagnosis was confirmed histopathologically. Thirty-five patients with TETs (average age, 51.97 years) and 21 patients with thymic cysts (average age, 50.54 years) were included. The region of interest for the lesion on the energy spectrum CT was delineated on the post-processing workstation, and multiple parameters of the energy spectrum CT were obtained. The diagnostic efficacies of the parameters were analysed using receiver operating characteristic (ROC) curves.

RESULTS

To distinguish small TETs from thymic cysts, a single-energy CT value of 60 keV showed good differential diagnostic performance in the arterial phase (cut-off value = 68.42 HU; area under the curve [AUC] = 0.978), a single-energy CT value of 70 keV showed good differential diagnostic performance in the venous phase (cut-off value = 59.77 HU; AUC = 0.956). In the arterial and venous phases, effective atomic numbers of 8.065 and 8.175, respectively, were used as cut-off values to distinguish small TETs from thymic cysts (AUC = 0.972 and AUC = 0.961, respectively). Iodine concentrations of 10.99 and 11.05 were used as cut-off values to distinguish small TETs from thymic cysts (AUC = 0.956 and AUC = 0.924, respectively).

CONCLUSION

According to the present study, energy spectrum CT parameters may have clinical value in the differential diagnosis of TETs and thymic cysts.

[Clinical characteristics, surgical treatment and prognosis of rolandic and perirolandic drug-resistant epilepsies]

Objective: To explore the clinical characteristics, treatment strategies and prognosis of rolandic and perirolandic drug-resistant epilepsies (DREs). Methods: The clinical data of 53 patients diagnosed with rolandic or perirolandic DRE who were admitted to Epilepsy Center, Sanbo Brain Hospital of Capital Medical University from January 2008 to January 2019 were retrospectively analyzed. The patients were divided into resective therapy group and non-resective therapy group [bipolar electrocoagulation on cortex, stereotactic electroencephalography (SEEG)-guided radiofrequency thermocoagulation, and vagus nerve stimulation]. The outcomes of epilepsy and post-surgical limb function were compared and analyzed. Results: A total of 53 patients were included, aged from 3 to 45 years old [(19±11) years], with 33 males and 20 females. Thirty patients received resective therapy and 23 patients received non-resective therapy. The curative effect of the resective therapy group was significantly better than that of the non-resective therapy group. The rate of Engel Ⅰ in resective therapy group was higher than that of non-resective group [83.3% (25/30) vs 39.1% (9/23), P=0.011). Compared with the non-resective group, the incidence of muscle strength decline in the resective group was higher both at 1 week [73.3% (22/30) vs 21.7% (5/23), P=0.006] and 3 months [30% (9/30) vs 0, P=0.016] after surgery. Conclusions: During the diagnosis and treatment, the multimodal method is conducive to the qualitative and localized diagnosis of the rolandic or perirolandic epilepsy, while SEEG has important value in the diagnosis, functional localization and treatment of the disease. Resective therapy is still the most effective method to terminate epilepsy, but it has a higher risk of post-surgical dysfunction.

[Identification of factors affecting Oncomelania hupensis density in Eastern Dongting Lake regions]

OBJECTIVE

To evaluate the impact of water pollutants, water levels and meteorological factors on the Oncomelania hupensis density in Eastern Dongting Lake regions, so as to provide insights into schistosomiasis control.

METHODS

O. hupensis snails were surveyed using a systematic sampling method in snail-infested marshlands in Eastern Dongting Lake regions from 2007 to 2014, and data pertaining to water pollutants, water levels and meteorological factors were collected. The duration of submergence and the date of the start of submergence were calculated. The snail density and its influencing factors were descriptively analyzed, and a linear mixed model was generated to examine the impacts of variables on the snail density. In addition, smooth curves were fitted to investigate the relationship between snail density and variables.

RESULTS

The snail density appeared a fluctuation in Eastern Dongting Lake regions during the period from 2007 to 2014, with the highest density on October, 2010 (52.79 snails/0.1 m²) and the lowest density on January 2009 (2.15 snails/0.1 m²). Linear mixed-model analysis showed that permanganate index, total phosphorus and the date of the start of submergence affected the snail density (t = 6.386, -2.920 and -3.892, all P values < 0.01). Smooth curve analysis revealed that the associations of the snail density with the permanganate index and total phosphorus appeared an approximately quadratic curve. After the end of April, the earlier date of the start of submergence resulted in a higher snail density.

CONCLUSIONS

Permenganate index, total phosphorus and the date of the start of submergence affect the O. hupensis snail density in Eastern Dongting Lake regions.

Extrusion-based 3D printed magnesium scaffolds with multifunctional MgF2 and MgF2-CaP coatings

Additively manufactured (AM) biodegradable magnesium (Mg) scaffolds with precisely controlled and fully interconnected porous structures offer unprecedented potential as temporary bone substitutes and for bone regeneration in critical-sized bone defects. However, current attempts to apply AM techniques, mainly powder bed fusion AM, for the preparation of Mg scaffolds, have encountered some crucial difficulties related to safety in AM operations and severe oxidation during AM processes. To avoid these difficulties, extrusion-based 3D printing has been recently developed to prepare porous Mg scaffolds with highly interconnected structures. However, limited bioactivity and a too high rate of biodegradation remain the major challenges that need to be addressed. Here, we present a new generation of extrusion-based 3D printed porous Mg scaffolds that are coated with MgF₂ and MgF₂-CaP to improve their corrosion resistance and biocompatibility, thereby bringing the AM scaffolds closer to meeting the clinical requirements for bone substitutes. The mechanical properties, in vitro biodegradation behavior, electrochemical response, and biocompatibility of the 3D printed Mg scaffolds with a macroporosity of 55% and a strut density of 92% were evaluated. Furthermore, comparisons were made between the bare scaffolds and the scaffolds with coatings. The coating not only covered the struts but also infiltrated the struts through micropores, resulting in decreases in both macro- and micro-porosity. The bare Mg scaffolds exhibited poor corrosion resistance due to the highly interconnected porous structure, while the MgF₂-CaP coatings remarkably improved the corrosion resistance, lowering the biodegradation rate of the scaffolds down to 0.2 mm y^-1. The compressive mechanical properties of the bare and coated Mg scaffolds before and during in vitro immersion tests for up to 7 days were both in the range of the values reported for the trabecular bone. Moreover, direct culture of MC3T3-E1 preosteoblasts on the coated Mg scaffolds confirmed their good biocompatibility. Overall, this study clearly demonstrated the great potential of MgF₂-CaP coated porous Mg prepared by extrusion-based 3D printing for further development as a bone substitute.

Paediatric/young versus adult patients with congenital long QT syndrome or catecholaminergic polymorphic ventricular tachycardia

Introduction

Congenital long QT syndrome (LQTS) and catecholaminergic ventricular tachycardia (CPVT) are less prevalent cardiac ion channelopathies than Brugada syndrome in Asia. The present study compared paediatric/young and adult patients with these conditions.

Method

This was a territory-wide retrospective cohort study of consecutive patients diagnosed with congenital LQTS and CPVT attending public hospitals in Hong Kong. The primary outcome was spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF).

Results

A total of 142 congenital LQTS (mean onset age= 27±23 years old) and 16 CPVT (mean presentation age=11±4 years old) patients were included. For congenital LQTS, arrhythmias other than VT/VF (HR=4.67, 95% confidence interval = [1.53–14.3], p=0.007), initial VT/VF (HR=3.25 [1.29–8.16], p=0.012) and Schwartz score (HR=1.90 [1.11–3.26], p=0.020) were predictive of the primary outcome for the overall cohort, whilst arrhythmias other than VT/VF (HR=5.41 [1.36–21.4], p=0.016) and Schwartz score (HR=4.67 [1.48–14.7], p=0.009) were predictive for the adult subgroup (&gt;25 years old; n=58). All CPVT patients presented before the age of 25 but no significant predictors of VT/VF were identified. A random survival forest model identified initial VT/VF, Schwartz score, initial QTc interval, family history of LQTS, initially asymptomatic, and arrhythmias other than VT/VF as the most important variables for risk prediction in LQTS, and initial VT/VF/sudden cardiac death, palpitations, QTc, initially symptomatic and heart rate in CPVT.

Conclusion

Clinical and ECG presentation vary between the pediatric/young and adult congenital LQTS population. All CPVT patients presented before the age of 25. Machine learning models achieved more accurate VT/VF prediction.

Funding Acknowledgement

Type of funding sources: None. Kaplan-Meier survival curve for LQTSKaplan-Meier survival curve for CPVT

A model of lifetime health outcomes in cardiovascular disease based on clinical trials and large cohorts

Background and purpose

Cardiovascular disease (CVD) risk of individuals depends on their socio-demographic characteristics, clinical risk factors, and treatments, and strongly influences their quality of life and survival. Individual-based long-term disease models, which aim to more accurately calculate the lifetime consequences, can help to target treatments, develop disease management programmes, and assess the value of new therapies. We present a new micro-simulation CVD model.

Methods

This micro-simulation model was developed using individual participant data from the Cholesterol Treatment Trialists' collaboration (CTT: 118,000 participants; 15 trials) and calibrated (with added socioeconomic deprivation, ethnicity, physical activity, mental illness, cancer and incident diabetes) in the UK Biobank cohort (UKB: 502,000 participants). Parametric survival models estimated risks of key endpoints (myocardial infarction (MI), stroke, coronary revascularisation (CRV), diabetes, cancer and vascular (VD) and nonvascular death (NVD) using participants' age, sex, ethnicity, physical activity, socioeconomic deprivation, smoking history, lipids, blood pressure, creatinine, previous cardiovascular diseases, diabetes, mental illness and cancer at entry and non-fatal incidents of the key endpoints during follow-up. The model integrates the risk equations and enables annual projection of endpoints and survival over individuals' lifetimes. The model was used to project remaining life expectancy across UK Biobank participants.

Results

Nonfatal cardiovascular events and age were the major determinants of CVD risk and, together with incident diabetes and cancer, of individuals' survival. The cumulative incidence of the key endpoints predicted by the CTT-UKB model corresponded well to their observed incidence in the UK Biobank cohort, overall (Figure 1) and in categories of participants by age, sex, prior CVD and CVD risk. Predicted remaining life expectancy across UK Biobank participants without history of CVD ranged between 22 and 43 years in men and between 24 and 46 years in women, depending on their age and CVD risk (Figure 2). Among UK Biobank participants with history of CVD, depending on their age, predicted remaining life expectancy ranged from 20 to 32 years in men and from 26 to 38 years in women.

Conclusion

This new lifetime CVD model accurately predicts morbidity and mortality in a large UK population cohort. It will be made available to provide individualised projections of expected lifetime health outcomes and benefits of treatments.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): UK National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme, UK Medical Research Council (MRC), British Heart Foundation Figure 1. Predicted (in black) versus observed (95% CI; in red) incidence of major clinical outcomes in the UK Biobank.Figure 2. Predicted remaining life expectancy of participants in UK Biobank cohort, by age and CVD risk or previous CVD at entry. QRISK, a 10-year CVD risk scoring algorithm for people without previous CVD, recommended for use in the UK National Health Service.

Derivation of an electronic frailty index for short-term mortality in heart failure: a machine learning approach

Objective

Frailty may be found in heart failure patients especially in the elderly and is associated with a poor prognosis. However, assessment of frailty status is time-consuming and the electronic frailty indices developed using health records have served as useful surrogates. We hypothesized that an electronic frailty index developed using machine learning can improve short-term mortality prediction in patients with heart failure.

Methods

This was a retrospective observational study included patients admitted to nine public hospitals for heart failure from Hong Kong between 2013 and 2017. Age, sex, variables in the modified frailty index, Deyo's Charlson comorbidity index (≥2), neutrophil-to-lymphocyte ratio (NLR) and prognostic nutritional index (PNI) were analyzed. Gradient boosting, which is a supervised sequential ensemble learning algorithm with weak prediction submodels (typically decision trees), was applied to predict mortality. Variables were ranked in the order of importance with a total score of 100 and used to build the predictive models. Comparisons were made with decision tree and multivariate logistic regression.

Results

A total of 8893 patients (median: age 81, Q1-Q3: 71–87 years old) were included, in whom 9% had 30-day mortality and 17% had 90-day mortality. PNI, age and NLR were the most important variables predicting 30-day mortality (importance score: 37.4, 32.1, 20.5, respectively) and 90-day mortality (importance score: 35.3, 36.3, 14.6, respectively). Gradient boosting significantly outperformed decision tree and multivariate logistic regression (area under the curve: 0.90, 0.86 and 0.86 for 30-day mortality; 0.92, 0.89 and 0.86 for 90-day mortality).

Conclusions

The electronic frailty index based on comorbidities, inflammation and nutrition information can readily predict mortality outcomes. Their predictive performances were significantly improved by gradient boosting techniques.

Funding Acknowledgement

Type of funding sources: None.

A territory-wide study of arrhythmogenic right ventricular cardiomyopathy patients from Hong Kong

Background

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a hereditary disease characterised by fibrofatty infiltration of the right ventricular myocardium that predisposes affected patients to malignant ventricular arrhythmias, dual-chamber cardiac failure and sudden cardiac death (SCD).

Methods

This was a territory-wide retrospective cohort study of patients diagnosed with ARVC/D between 1997 and 2019. The primary outcome was incident ventricular tachycardia/ventricular fibrillation (VT/VF). The secondary outcomes were new-onset heart failure with reduced ejection fraction (HFrEF) and all-cause mortality.

Results

This study consisted of 115 ARVC/D patients (median age: 60 [44.1–70.2] years; 58% male). Of these, 51 and 24 patients developed incident VT/VF and new-onset HFrEF, respectively. Five patients underwent cardiac transplantation, and 14 died during follow-up. Multivariate Cox regression identified prolonged QRS duration as a predictor of VT/VF (P&lt;0.05). Female gender, prolonged QTc duration, the presence of epsilon waves and T-wave inversion (TWI) in any lead except aVR/V1 predicted new-onset HFrEF (P&lt;0.05). Female gender, prolonged QTc duration and the presence of epsilon waves, in addition to the parameters of older age at diagnosis of ARVC/D, prolonged QRS duration and worsening ejection fraction predicted all-cause mortality (p&lt;0.05). Clinical scores were also developed to predict new-onset HFrEF (Table 1a-c) and all-cause mortality (Table 2a-c). This was followed by the application of a non-parametric machine learning survival analysis models for outcome prediction. These machine learning algorithms better capture nonlinear and interactive patterns within survival data compared to traditionally used Cox regression models, which assume the existence of a hazard function between survival data and censored outcomes. The present study introduced weighted random survival forests models for the prediction of incident VT/VF, HFrEF and all-cause mortality. Findings indicate that these machine learning wRSF models performed the best in the prediction of all three aforementioned outcomes compared to other analytical methods.

Conclusion

Clinical and electrocardiographic parameters are important for assessing prognosis in ARVC/D patients. Machine learning algorithms appear to be the most optimal tools for event prediction, and as such should potentially be used to aid risk stratification and decision-making in the clinical setting.

Funding Acknowledgement

Type of funding sources: None.

Prevalence and impact of metabolic syndrome in patients with multivessel coronary artery disease and acute coronary syndrome

Background

Metabolic syndrome is associated with increased incidence of diabetes and cardiovascular diseases in patients initially free from these diseases. However, its prognostic value in patients with established coronary artery diseases remains controversial.

Purpose

Therefore, we aimed to illustrate the prevalence and investigate the impact of metabolic syndrome in patients with multivessel coronary artery disease and acute coronary syndrome.

Methods

We conducted a large registry of consecutive patients with acute coronary syndrome referred to primary percutaneous coronary intervention and those with multivessel diseases were eligible for this analysis. Metabolic syndrome was defined using modified criteria based on the Adult Treatment Panel III definition from the National Cholesterol Education Program. The primary outcome was major adverse cardiovascular events (MACE), a composite of all-cause death, myocardial infarction, and stroke.

Results

A total of 2532 patients were included in current analysis and 993 (39.2%) of them had metabolic syndrome while 1539 (60.8%) did not. The prevalence of metabolic syndrome increased over the study period (p for trend = 0.005). There was a significant decline of metabolic syndrome prevalence in patients over 60 years old (p for trend = 0.002) and females had a higher prevalence than their male counterparts (61.5% verse 32.9%, p&lt;0.001). Over a median follow-up of 2.3 years, metabolic syndrome was not significantly associated with MACE (adjusted 95% CI 0.92 to 1.54). In addition, there was no significant difference observed between two groups in other individual outcomes, namely all-cause death, cardiac death, stroke, myocardial infarction, and any revascularization.

Conclusions

Metabolic syndrome was frequently observed in patients with multivessel coronary artery disease and acute coronary syndrome. Patients with metabolic syndrome were more likely to be young and female. However, it was not an independent predictor for MACE after primary percutaneous coronary intervention in those patients.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences Metabolic syndrome distribution in MVDOutcome according to metabolic syndrome

Tributyrin supplementation in pasteurized waste milk: Effects on growth performance, health, and blood parameters of dairy calves

This study evaluated the effects of incremental tributyrin supplementation in pasteurized waste milk on growth performance, health, and blood metabolism of dairy calves before and after weaning. Forty-eight newborn female Holstein dairy calves (39.6 ± 2.75 kg; mean ± standard deviation) were blocked by age and randomly assigned to 3 treatments: pasteurized waste milk (1) without supplementation, (2) with 1 g/L of tributyrin products (unprotected solid powder; containing 35% tributyrin), or (3) with 2 g/L of tributyrin products. The calves were weaned on d 56 and were raised until d 77. Data were analyzed for the preweaning, postweaning, and overall periods. The results showed that starter intake and hay intake were not different among treatments in any period of the trial, but the crude protein intake tended to increase linearly with tributyrin supplementation during the overall period. Although tributyrin supplementation had no effects on body weight during preweaning and overall periods, body weight increased linearly with tributyrin supplementation postweaning. The average daily gain tended to increase linearly during postweaning and overall periods. No effects were observed on feed efficiency in any period. A positive linear relationship between body length and tributyrin supplementation was observed during the postweaning period, but no differences were found for the other body structural measurements in any period. The results of diarrhea showed that tributyrin concentration had a negative linear relationship with diarrhea frequency during preweaning and overall periods. The rectal temperature did not differ among treatments in any period, but a treatment × week effect for rectal body temperature was observed. For blood metabolism, tributyrin supplementation had no effects on insulin, growth hormone, total protein, albumin, or globulin. No differences were found in serum amyloid A concentration in any of the periods, yet haptoglobin concentration decreased linearly with increasing tributyrin concentration during postweaning and overall periods. Endothelin concentration showed a tendency to decrease linearly during preweaning and postweaning periods and decreased linearly with tributyrin supplementation during the overall period. An increasing tributyrin concentration was associated with a negative linear relationship with IL-1β concentration during the preweaning period, and no differences were found in the other periods. The concentration of IL-6 and tumor necrosis factor α were not different among treatments in any of the periods. These data suggest that increasing the concentration of tributyrin in pasteurized waste milk could increase growth performance and health of dairy calves, and incremental tributyrin supplementation could linearly reduce haptoglobin, endothelin, and IL-1β concentrations, indicating a positive effect of tributyrin on alleviating oxidative stress and inflammatory status of dairy calves. Calves fed pasteurized waste milk supplemented with tributyrin products (containing 35% tributyrin) at 2 g/L compared with 1 g/L of milk had more improved growth and health.

[Effect of splenectomy on the risk of hepatocellular carcinoma development among patients with liver cirrhosis and portal hypertension: a multi-institutional cohort study]

Objective: To identify whether splenectomy for treatment of hypersplenism has any impact on development of hepatocellular carcinoma(HCC) among patients with liver cirrhosis and hepatitis. Methods: Patients who underwent splenectomy for hypersplenism secondary to liver cirrhosis and portal hypertension between January 2008 and December 2012 were included from seven hospitals in China, whereas patients receiving medication treatments for liver cirrhosis and portal hypertension (non-splenectomy) at the same time period among the seven hospitals were included as control groups. In the splenectomy group, all the patients received open or laparoscopic splenectomy with or without pericardial devascularization. In contrast, patients in the control group were treated conservatively for liver cirrhosis and portal hypertension with medicines (non-splenectomy) with no invasive treatments, such as transjugular intrahepatic portosystemic shunt, splenectomy or liver transplantation before HCC development. All the patients were routinely screened for HCC development with abdominal ultrasound, liver function and alpha-fetoprotein every 3 to 6 months. To minimize the selection bias, propensity score matching (PSM) was used to match the baseline data of patients among splenectomy versus non-splenectomy groups. The Kaplan-Meier method was used to calculate the overall survival and cumulative incidence of HCC development, and the Log-rank test was used to compare the survival or disease rates between the two groups. Univariate and Cox proportional hazard regression models were used to analyze the potential risk factors associated with development of HCC. Results: A total of 871 patients with liver cirrhosis and hypertension were included synchronously from 7 tertiary hospitals. Among them, 407 patients had a history of splenectomy for hypersplenism (splenectomy group), whereas 464 patients who received medical treatment but not splenectomy (non-splenectomy group). After PSM,233 pairs of patients were matched in adjusted cohorts. The cumulative incidence of HCC diagnosis at 1,3,5 and 7 years were 1%,6%,7% and 15% in the splenectomy group, which was significantly lower than 1%,6%,15% and 23% in the non-splenectomy group (HR=0.53,95%CI:0.31 to 0.91,P=0.028). On multivariable analysis, splenectomy was independently associated with decreased risk of HCC development (HR=0.55,95%CI:0.32 to 0.95,P=0.031). The cumulative survival rates of all the patients at 1,3,5,and 7 years were 100%,97%,91%,86% in the splenectomy group,which was similar with that of 100%,97%,92%,84% in the non-splenectomy group (P=0.899). In total,49 patients (12.0%) among splenectomy group and 75 patients (16.2%) in non-splenectomy group developed HCC during the study period, respectively. Compared to patients in non-splenectomy group, patients who developed HCC after splenectomy were unlikely to receive curative resection for HCC (12.2% vs. 33.3%,χ²=7.029, P=0.008). Conclusion: Splenectomy for treatment of hypersplenism may decrease the risk of HCC development among patients with liver cirrhosis and portal hypertension.

Exosome-mediated transfer of MIF confers temozolomide resistance by regulating TIMP3/PI3K/AKT axis in gliomas

Temozolomide (TMZ) resistance is an important cause of clinical treatment failure and poor prognosis in gliomas. Increasing evidence indicates that cancer-derived exosomes contribute to chemoresistance; however, the specific contribution of glioma-derived exosomes remains unclear. The aim of this study was to explore the role and underlying mechanisms of exosomal macrophage migration inhibitory factor (MIF) on TMZ resistance in gliomas. We first demonstrated that MIF was upregulated in the exosomes of TMZ-resistant cells, engendering the transfer of TMZ resistance to sensitive cells. Our results indicated that exosomal MIF conferred TMZ resistance to sensitive cells through the enhancement of cell proliferation and the repression of cell apoptosis upon TMZ exposure. MIF knockdown enhanced TMZ sensitivity in resistant glioma cells by upregulating Metalloproteinase Inhibitor 3 (TIMP3) and subsequently suppressing the PI3K/AKT signaling pathway. Additionally, exosomal MIF promoted tumor growth and TMZ resistance of glioma cells in vivo, while IOS-1 (MIF inhibitor) promotes glioma TMZ sensitive in vivo. Taken together, our study demonstrated that exosome-mediated transfer of MIF enhanced TMZ resistance in glioma through downregulating TIMP3 and further activating the PI3K/AKT signaling pathway, highlighting a prognostic biomarker and promising therapeutic target for TMZ treatment in gliomas.

[Evaluation of shoulder function after repairing head and neck defects with supraclavicular flap]

Objective: To evaluate the shoulder function in patients after repair of head and neck defects with supraclavicular flap. Methods: A retrospective analysis was performed on 56 patients (54 males, 2 females, aged 35-74 years old) who received the repair of head and neck defects with supraclavicular flaps at Department of Otorhinolaryngology Head and Neck Surgery of Beijing Tongren Hospital, Capital Medical University in January 2013-December 2020. The areas and types of flaps, disruption or infections of the incision at the donor sites and other postoperative complications were recorded. Quick disabilities of the arm, shoulder and hand (Quick-DASH) was used for evaluating the shoulder functions in 43 patients conforming to the standard for evaluation of the clinical functions of shoulders and upper limbs, to compare the postoperative upper limb functions between patients treated with clavicular flaps and patients with acromion flaps. Meanwhile, 30 patients who received bilateral neck lymph node dissection over the same period of time were selected for a comparative evaluation of the donor sides (observation group) and the opposite sides (control group). Data were processed with SPSS 22.0. Results: The areas of obtained supraclavicular flaps were (4-10) cm × (10-18) cm. Three patients (5%) showed the defect widths of 8-10 cm at the donor sites, which couldn't be sutured directly, received the repair of their shoulder defects with partial flaps. Defects in other patients were sutured directly. After surgery, 3 patients (5%) suffered from disruption of the acromion incision, which healed after 2 weeks of local dressing. The follow-up time was 6-43 (27±14) months. All patients expressed no dissatisfaction with the appearance. Among 43 patients, 28 (65%) were clavicular type and 15 (35%) were acromion type. The acromion type showed average motor ability and Quick-DASH scores higher than the clavicular type [(average motor ability: (14.4±4.7) vs. (11.8±3.1), t=2.105, P=0.048; Quick-DASH: (16.9±11.6) vs. (12.2±7.1), t=2.284, P=0.033]. Among 30 patients who received bilateral neck lymph node dissection over the same period of time, the observation group showed higher average motor ability, local symptoms and Quick-DASH scores than the control group [average motor ability: (13.4±5.8) vs. (9.8±4.2), t=3.024, P=0.004; average local symptoms: (4.1±1.0) vs. (3.4±1.0), t=2.537, P=0.014; Quick-DASH: (15.6±14.7) vs. (5.2±11.1), t=3.106, P=0.003]. Conclusion: Shoulder dysfunction exists after treatment with supraclavicular flap, which is related to the flap type.

Effects of isometric resistance exercise of the lower limbs on intraocular pressure and ocular perfusion pressure among healthy adults: A meta-analysis

BACKGROUND

The main risks for glaucoma are increased intraocular pressure (IOP) and decreased ocular perfusion pressure (OPP). This review aims to examine the potential impact of lower limb isometric resistance exercise on intraocular pressure and ocular perfusion pressure.

METHOD

A meta-analysis was conducted to determine the potential impact of isometric exercise on IOP and OPP. The literature on the relationship between isometric resistance exercise and IOP was systematically searched according to the "Cochrane Handbook" in the databases of Pubmed, Web of Science, EBSCO, and Scopus through December 31, 2020. The search terms used were "exercise," "train," "isometric," "intraocular pressure," and "ocular perfusion pressure," and the mean differences of the data were analyzed using the Stata 16.0 software, with a 95% confidence interval.

RESULTS

A total of 13 studies, which included 268 adult participants consisting of 162 men and 106 women, were selected. All the exercise programs that were included were isometric resistance exercises of the lower limbs with intervention times of 1min, 2min, or 6min. The increase in IOP after intervention was as follows: I²=87.1%, P=0.001 using random-effects model combined statistics, SMD=1.03 (0.48, 1.59), and the increase in OPP was as follows: I²=94.5%, P=0.001 using random-effects model combined statistics, SMD=2.94 (1.65, 4.22), with both results showing high heterogeneity.

CONCLUSION

As isometric exercise may cause an increase in IOP and OPP, therefore, people with glaucoma and related high risk should perform isometric exercise with caution.

Identification of a Costimulatory Molecule Gene Signature to Predict Survival and Immunotherapy Response in Head and Neck Squamous Cell Carcinoma

Background

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies worldwide. Checkpoint blockade immunotherapy has made tremendous progress in the treatment of a variety of cancers in recent years. Costimulatory molecules constitute the foundation of cancer immunotherapies and are deemed to be promising targets for cancer treatment. This study attempted to evaluate the potential value of costimulatory molecule genes (CMGs) in HNSCC.

Materials and Methods

Based on The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) dataset, we identified the prognostic value of CMGs in HNSCC. Subsequently, CMGs-based signature (CMS) to predict overall survival of HNSCC patients was established and validated. The differences of downstream pathways, clinical outcomes, immune cell infiltration, and predictive immunotherapy responses between different CMS subgroups were investigated via bioinformatic algorithms. We also explored the biological functions of TNFRSF12A, one risk factor of CMS, by in vitro experiments.

Results

Among CMGs, 22 genes were related to prognosis based on clinical survival time in HNSCC. Nine prognosis-related CMGs were selected to establish CMS. CMS was an independent risk factor and could indicate the survival of HNSCC patients, the component of tumor-infiltrating lymphocytes, and the immunotherapy response rate. Functional enrichment analysis confirmed that CMS might involve immune-relevant processes. Additionally, TNFRSF12A was related to poor prognosis and enhanced malignant phenotype of HNSCC.

Conclusion

Collectively, CMS could accurately indicate prognosis, evaluate the tumor immune microenvironment, and predict possible immunotherapy outcomes for HNSCC patients.

Genome-wide association study reveals a quantitative trait locus and two candidate genes on Sus scrofa chromosome 5 affecting intramuscular fat content in Suhuai pigs

Intramuscular fat content (IFC) is an essential quantitative trait of meat, affecting multiple meat quality indicators. A certain amount of IFC could not only improve the sensory score of pork but also increase the flavour, tenderness, juiciness and shelf-life. To dissect the genetic determinants of IFC, two methods, including genome-wide efficient mixed-model analysis (GEMMA) and linkage disequilibrium adjusted kinships (LDAKs), were used to carry out genome-wide association studies for IFC in Suhuai pig population. A total of 14 and 18 significant single nucleotide polymorphisms (SNPs) were identified by GEMMA and LDAK, respectively. The results of these two methods were highly consistent and all 14 significant SNPs in GEMMA were detected by LDAK. Seven of the 18 SNPs reached the genome-wide significance level (P < 9.85E-07) while 11 cases reached the suggestive significance level (P < 1.77E-05). These significant SNPs were mainly distributed on Sus scrofa chromosome (SSC) 5, 3, and 7. Moreover, one locus resides in a 2.27 Mb (71.37-73.64 Mb) region on SSC5 harbouring 13 significant SNPs associated with IFC, and the lead SNP (rs81302978) also locates in this region. Linkage disequilibrium (LD) analysis showed that there were four pairs of complete LD (r² = 1) among these 13 SNPs, and the remaining 9 SNPs with incomplete LD (r² ≠ 1) were selected for subsequent analyses of IFC. Association analyses showed that 7 out of 9 SNPs were significantly associated with IFC (P < 0.05) in 330 Suhuai pigs, and the other 2 SNPs tended to reach a significant association level with IFC (P < 0.1). The phenotypic variance explained (PVE) range of these 9 SNPs was 0.92-3.55%. Meanwhile, the lead SNP was also significantly associated (rs81302978) with IFC (P < 0.05) in 378 commercial hybrid pigs (Pietrain × Duroc) × (Landrace × Yorkshire) (PDLY), and the PVE was 1.38%. Besides, two lipid metabolism-relevant candidate genes, the leucine rich repeat kinase 2 (LRRK2) and PDZ domain containing ring finger 4 (PDZRN4) were identified in the 2.27 Mb region on SSC5. In conclusion, our results may provide a set of markers useful for genetic improvement of IFC in pigs and will advance the genome selection process of IFC on pig breeding programmes.

[Repair methods and clinical effects of full-thickness burn wounds deep to tendon or even bone in fingers]

Objective: To explore the repair methods and clinical effects of full-thickness burn wounds deep to tendon or even bone in fingers. Methods: A retrospective non-randomized controlled trial was conducted on the 98 patients with full-thickness finger burns deep to tendon or even bone who met the inclusion criteria and were hospitalized in Xiangya Hospital of Central South University from January 2010 to December 2019. Among the 98 patients, there were 81 males and 17 females, aged from 1 to 72 years, with 160 fingers involved. The wound area of each of affected fingers ranged from 2.0 cm×1.5 cm to 12.0 cm×3.5 cm, and the maximum wound area after merging the affected fingers was 12.0 cm×10.0 cm. For adult hands with multiple full-thickness burn wounds deep to tendon or even bone in multiple fingers or children with full-thickness finger burns deep to tendon or even bone, pedicled abdominal flaps were selected. For adults with single or two fingers with full-thickness burns deep to tendon or even bone, the pedicled internal hand flaps and free tissue flaps were selected. The free tissue flap repair requires good vascular conditions in the recipient area with arteries and veins available for anastomosis. For thumb nail burns deep to tendon or even bone or partial absence of the thumb after burns, the thumbs were reconstructed with the first toenail flap or dorsal foot flap with the second toe. In this study, 45 pedicled abdominal flaps were used to repair the wounds in 91 fingers, 37 pedicled internal hand flaps were used to repair the wounds in 37 fingers, 26 free tissue flaps were used to repair the wounds in 28 fingers, 3 first toenail flaps were used to reconstruct 3 patients' thumb nails and to repair hand wounds, and 1 dorsal foot flap with the second toe was used to reconstruct 1 patient's thumb and to repair hand and wrist wounds. The tissue flap area was from 2.0 cm×1.5 cm to 20.0 cm×10.0 cm. The wound in the donor site was repaired by direct suture or full-thickness skin grafting from the medial upper arm of the affected limb or split-thickness skin grafting from the outer thigh. The postoperative survival of the tissue flap, postoperative complications, and appearance and function of the flap donor site were observed. For the patients who were followed up, their finger functions were evaluated at the last follow-up using the trial criteria for replantation function evaluation of the amputated finger issued by the Hand Surgery Society of the Chinese Medical Association, and the satisfaction of the patients was investigated using the Efficacy Satisfaction Scale. Data were statistically analyzed with Kruskal-Wallis H test and Nemenyi test. Results: Of the 112 tissue flaps, 104 tissue flaps survived completely and had good blood circulation; 1 pedicled thumb dorsal ulnar reverse island flap, 1 pedicled finger artery cutaneous branch reverse island flap, and 1 free grafted anterolateral thigh perforator flap were slightly necrotic at the end, which were repaired with outer thigh split-thickness skin graft after dressing change and granulation tissue growth; 2 free grafted tarsal external artery flaps and 1 pedicled thumb dorsal ulnar reverse island flap suffered from postoperative venous return obstruction, which survived after partial suture removal and heparin saline cleansing of the wound; 1 pedicled modified dorsal metacarpal artery retrograde island flap and 1 free grafted peroneal artery perforator flap were necrotic, which were repaired by a pedicled abdominal flap and a lateral upper arm flap free transplantation respectively in stage Ⅱ. After transplantation, the tissue flaps had good shape, soft texture, and good elasticity, without bloating. There was no functional disorder in the flap donor site, and only slight scar remained. A total of 117 fingers of the 72 patients received 3-24 months of outpatient or telephone follow-up. At the last follow-up, the excellent and good rates of function evaluation of fingers repaired with pedicled abdominal flap, pedicled internal hand flap, and free tissue flap were respectively 77.3% (51/66), 96.3% (26/27), and 95.8% (23/24). The function of fingers repaired with free tissue flap and pedicled internal hand flap was significantly better than that with pedicled abdominal flap (P<0.01). The satisfaction of patients with fingers repaired by free tissue flaps was significantly higher than that by pedicled abdominal flap (P<0.05). Conclusions: According to the specific situation of full-thickness burn wounds deep to tendon or even bone in fingers, the pedicled abdominal flap is used to repair the multiple full-thickness burn wounds deep to tendon or even bone in multiple fingers of adult or the full-thickness burn wounds deep to tendon or even bone in fingers of children, the pedicled internal hand flap or free tissue flap is used to repair the full-thickness burn wounds deep to tendon or even bone in single or two fingers of adult patients, and the first toenail flap or the dorsal foot flap with the second toe is used to reconstruct the thumbs with full-thickness burn deep to tendon or even bone, with high postoperative tissue flap survival rate and few complications. The functional recovery of the affected finger is better after repair with free tissue flap and pedicled internal hand flap, and the patients' satisfaction is the highest after free tissue flap repair.

[Mesenchymal stem cells derived apoptotic extracellular vesicles attenuate pro-inflammatory macrophages induced by Porphyromonas gingivalis lipopolysaccharide]

Objective: To investigate whether bone marrow mesenchymal stem cells (BMMSCs) derived apoptotic extracellular vesicles (ApoEVs) could regulate the polarization of mouse macrophage cell line RAW264.7 and whether BMMSCs derived ApoEVs could attenuate pro-inflammatory condition of RAW264.7 induced by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS), so as to provide experimental evidence and theoretical basis for using BMMSCs derived ApoEVs as a method to treat periodontitis. Methods: The Operetta CLS high-content analysis system was used to observe the time-dependent apoptosis process of BMMSCs. Besides, field emission scanning electron microscopy (FESEM), dynamic light scattering technology and streaming potential method were used to measure the surface characteristics of BMMSCs derived ApoEVs. The Operetta CLS high-content analysis system was used to observe the process of RAW264.7 phagocyting 5-carboxy-tetramethylrhodamine, succinimidyl ester (5-TAMRA-SE) labeled ApoEVs. Real-time quantitative PCR was used to detect the mRNA expression of arginase-1 (Arg-1). Cell immunofluorescence and Western blotting were used to detect the number of inducible nitric oxide synthase (iNOS)(+) macrophages and iNOS protein expression level in each experiment group. Enzyme linked immunosorbent assay was used to detect tumor necrosis factro-α (TNF-α) level in the Pg-LPS induced pro-inflammatory macrophage culture supernatant in each experiment group. Results: After treating with 0.5 μmol/L staurosporine for 12 hours, mouse BMMSCs underwent shrinking with obvious vesicles structure around. The FESEM showed the ApoEVs were in spherical shapes. The size range of ApoEVs was about 100-1 000 nm and the average Zeta potential was -16.6 mV. The Operetta CLS high-content analysis system showed RAW264.7 could phagocytose 5-TAMRA-SE labeled ApoEVs by pseudopodia. The relative mRNA expression of Arg-1 was significantly increased in RAW 264.7 after being treated with interleukin 4 (IL-4) and ApoEVs (261.97±15.91) compared to that with IL-4 alone (115.29±15.42) (P<0.01). Cell immunofluorescence showed that ApoEVs could reduce the number of iNOS(+) macrophages induced by Pg-LPS (39.33±4.70) comparing to those without ApoEVs (95.33±4.70) (P=0.007). In the meanwhile, ApoEVs could also down-regulate the iNOS protein level of macrophages induced by Pg-LPS (5.84±1.05) comparing to those without ApoEVs (14.91±3.87) (P<0.01). Besides, ApoEVs could also reduce the TNF-α secretion in the culture supernatant of pro-inflammatory macrophages induced by Pg-LPS [(21 899.71±409.73) ng/L] comparing to those without ApoEVs [(71 296.50±2 344.22) ng/L] (P=0.003). Conclusions: BMMSCs derived ApoEVs could regulate the polarization of macrophages and could also attenuate the pro-inflammatory condition of macrophages induced by Pg-LPS.

Phototactic Behavioral Response of the Ectoparasitoid Beetle Dastarcus helophoroides (Coleoptera: Bothrideridae): Evidence for Attraction by Near-Infrared Light

The ectoparasitoid beetle, Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae), has been widely used as a biological control agent for many cerambycid beetles in China, Korea, and Japan. However, much less is known about its phototactic behavior to visual stimuli. In this paper, the phototactic behavioral response of D. helophoroides to 27 monochromatic lights and to nine illumination intensities of the most attractive light was evaluated using light-emitting diodes (LEDs) as light sources. The results showed that in dual choice between darkness and individual LED light, D. helophoroides adults exhibited a positively phototactic response to all wavelengths ranging from 300 to 860 nm. The near-infrared light (NIR, ranging from 700 to 760 nm) elicited stronger phototactic behavioral response, showing a preference for NIR wavelengths light. In paired choice among four preferred NIR lights, D. helophoroides adults displayed a significantly more favorable response to NIR light at 700 nm. Furthermore, the beetles expressed varying levels of sensitivity to illumination intensities from 1 to 600 lux under NIR light at 700 nm. The phototactic response was strongest at 7 lux and a statistically significant downward trend was found with increasing or decreasing the illumination intensities. These findings clearly demonstrate that D. helophoroides is a positively phototactic insect and its phototactic behavior is significantly influenced by light wavelength and illumination intensity, among which NIR light with peak wavelength at 700 nm and an intensity at 7 lux are most suitable in attracting D. helophoroides adults.

Application of Monte Carlo Algorithms to Cardiac Imaging Reconstruction

Monte Carlo algorithms have a growing impact on nuclear medicine reconstruction processes. One of the main limitations of myocardial perfusion imaging (MPI) is the effective mitigation of the scattering component, which is particularly challenging in Single Photon Emission Computed Tomography (SPECT). In SPECT, no timing information can be retrieved to locate the primary source photons. Monte Carlo methods allow an event-by-event simulation of the scattering kinematics, which can be incorporated into a model of the imaging system response. This approach was adopted in the late Nineties by several authors, and recently took advantage of the increased computational power made available by high-performance CPUs and GPUs. These recent developments enable a fast image reconstruction with improved image quality, compared to deterministic approaches. Deterministic approaches are based on energy-windowing of the detector response, and on the cumulative estimate and subtraction of the scattering component. In this paper, we review the main strategies and algorithms to correct the scattering effect in SPECT and focus on Monte Carlo developments, which nowadays allow the threedimensional reconstruction of SPECT cardiac images in a few seconds.