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Aneurisma Falso , Ventrículos Cardíacos , Imagen por Resonancia Magnética , Humanos , Imagen por Resonancia Magnética/métodos , Aneurisma Falso/diagnóstico , Ventrículos Cardíacos/diagnóstico por imagen , Masculino , Aneurisma Cardíaco/diagnóstico , Aneurisma Cardíaco/diagnóstico por imagenRESUMEN
OBJECTIVE: To evaluate the regulatory effect of Diwu Yanggan (DWYG) Decoction on lysoglycerophospholipids (Lyso-GPLs) in circulating exosomes in a mouse model of nonalcoholic fatty liver disease (NAFLD). METHODS: Circulating exosomes isolated from mouse serum by size exclusion chromatography were morphologically characterized using transmission electron microscope and examined for surface markers CD9, CD63 and TSG101 using Western blotting. Twenty-four male Kunming mice were randomized into 3 groups for normal feeding (control, n=8) or high-fat diet feeding for 1 week to induce NAFLD, after which the latter mice were given DWYG decoction (treatment group, n=8) or normal saline (model group, n=8) by gavage for 4 weeks. After the last treatment, blood samples were collected from the mice for testing serum TC, HDL-C, LDL-C, ALT and AST levels and isolating circulating exosomes. Using multivariate statistical analysis based on targeted metabolomics strategy, the potential biomarkers for Lyso-GPLs in the exosomes were screened. RESULTS: The isolated exosomes about 100 nm in size had a typical saucer-like structure with distinct double-layer membranes and a mean particle size of 137.5 nm and expressed the specific surface marker proteins CD9, CD63 and TSG101. The mouse models of NAFLD had significantly increased serum levels of TC, HDL-C, LDL-C and AST and lowered serum ALT level. A total of 43 Lyso-GPLs with significant reduction after DWYG Decoction treatment were identified in NAFLD mice. CONCLUSION: DWYG Decoction can regulate Lyso-GPLs in circulating exosomes in NAFLD mice, which provides a new clue for studying the therapeutic mechanism of DWYG Decoction for liver disease.
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Modelos Animales de Enfermedad , Medicamentos Herbarios Chinos , Exosomas , Enfermedad del Hígado Graso no Alcohólico , Animales , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Enfermedad del Hígado Graso no Alcohólico/sangre , Exosomas/metabolismo , Ratones , Medicamentos Herbarios Chinos/farmacología , Medicamentos Herbarios Chinos/uso terapéutico , Masculino , Dieta Alta en Grasa/efectos adversos , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Ratones Endogámicos , Tetraspanina 30/metabolismo , Proteínas de Unión al ADN , Factores de Transcripción , Animales no ConsanguíneosRESUMEN
Objective: To investigate the clinical effect of over-the-top (OTT) reconstruction of the anterior cruciate ligament (ACL) combined with the modified Lemaire technique in one-stage ACL revision. Methods: It's a retrospective study. The clinical data of 37 patients who underwent one-stage revision of ACL using OTT combined with modified Lemaire technique from April 2020 to May 2023 in the Department of Sports Medicine of Xinhua Hospital Affiliated to Dalian University were retrospectively analyzed. There were 28 males and 9 females with a mean age of (32.7±5.7) years. The postoperative knee function and surgical revision effect were evaluated by subjective and objective evaluation indexes of the knee joint before and 3 months and 24 months after surgery. The subjective evaluation indexes included the International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner score; and the objective evaluation indexes included the anterior-posterior static displacement distance of the tibia, tibia-femur relative rotation angle, the Lachman test, the axial shift test, and the ratio of the loss of muscle strength of the lower limb. Results: At the final follow-up, all patients returned to pre-injury motor level, with significant improvements in IKDC scores (45.3±6.8 preoperatively, 67.5±4.7 and 93.2±2.3 at 3 months and 2 years after the operation, respectively), Lysholm scores (57.2±2.6 preoperatively, 72.6±2.9 and 89.7±3.7 at 3 months and 2 years after the operation, respectively), and Tegner scores (3.1±0.7 preoperatively, 4.9±0.6 and 5.8±1.3 at 3 months and 2 years after the operation, respectively) (all P<0.001). The anterior-posterior static displacement distance of the tibia reduced significantly [from (5.2±0.5) mm before the operation to (1.4±0.5) mm at 2 years postoperatively) (P<0.001)]; and the relative rotation angle of the tibia-femur restored to the normal physiological range, it was reduced from 6.2°±1.2° before the operation to 1.7°±0.3° 2 years after (P<0.001). The Lachman test and axial shift test at 2 years postoperatively were all negative. The muscle strength loss ratio of the affected lower limb was significantly better than that before the operation (P<0.001). Conclusion: The use of OTT reconstruction combined with modified Lemaire technique for revision of ACL in patients with ACL reconstruction failure can circumvent the tunnel problem for one-stage revision and better restore the stability and function of the knee joint, with ideal clinical results.
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Reconstrucción del Ligamento Cruzado Anterior , Humanos , Reconstrucción del Ligamento Cruzado Anterior/métodos , Masculino , Femenino , Adulto , Estudios Retrospectivos , Resultado del Tratamiento , Lesiones del Ligamento Cruzado Anterior/cirugía , Ligamento Cruzado Anterior/cirugía , Articulación de la Rodilla/cirugíaRESUMEN
Objective: To investigate serum vitamin A and vitamin D status in children aged 2-<7 years in 20 cities in China. Methods: A cross-sectional study was conducted. A total of 2 924 healthy children aged 2-<7 years were recruited from September 2018 to September 2019 from 20 cities in China, categorized by age groups of 2-<3 years, 3-<5 years, and 5-<7 years. The demographic and economic characteristics and health-related information of the enrolled children were investigated. Body weight and height were measured by professional staff members. The serum vitamin A and vitamin D levels were detected by high-performance liquid chromatography-tandem mass spectrometry. Chi-square test and Logistic regression were applied to analyze the association between vitamin A and vitamin D deficiency and insufficiency as well as their underlying impact factors. Results: The age of the 2 924 enrolled children was 4.33 (3.42, 5.17) years. There were 1 726 males (59.03%) and 1 198 females (40.97%). The prevalences of vitamin A and vitamin D deficiency in enrolled children were 2.19% (64/2 924) and 3.52% (103/2 924), respectively, and the insufficiency rates were 29.27% (856/2 924) and 22.20% (649/2 924), respectively. Children with both vitamin A and vitamin D deficiencies or insufficiencies were found in 10.50% (307/2 924) of cases. Both vitamin A (χ2=7.91 and 8.06, both P=0.005) and vitamin D (χ2=71.35 and 115.10, both P<0.001) insufficiency rates were higher in children aged 3-<5 and 5-<7 years than those in children aged 2-<3 years. Vitamin A and vitamin D supplementation in the last 3 months was a protective factor for vitamin A and D deficiency and insufficiency, respectively (OR=0.68 and 0.22, 95%CI 0.49-0.95 and 0.13-0.40, both P<0.05). The rates of vitamin A and D insufficiency was higher in children with annual household incomes <60 000 RMB than in those with annual household incomes ≥60 000 RMB (χ2=34.11 and 10.43, both P<0.01). Northwest and Southwest had the highest rates of vitamin A and vitamin D insufficiency in children aged 2-<7 yeas, respectively (χ2=93.22 and 202.54, both P<0.001). Conclusions: Among 20 cities in China, children aged 2-<7 years experience high rates of vitamin A and vitamin D insufficiency, which are affected by age, family economic level, vitamin A and vitamin D supplementation, and regional economic level. The current results suggest that high level of attention should be paid to vitamin A and vitamin D nutritional status of preschool children.
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Deficiencia de Vitamina D , Vitamina D , Masculino , Femenino , Preescolar , Humanos , Vitamina A/análisis , Ciudades , Estudios Transversales , Vitaminas/análisis , Deficiencia de Vitamina D/epidemiología , China/epidemiología , PrevalenciaRESUMEN
OBJECTIVES: Observational studies have reported associations between dried fruit intake and DNA methylation(DNAm). However, inherent flaws in observational study designs make them susceptible to confounding and reverse causality bias. Consequently, it is unclear whether a causal association exists. In the present study, we aimed to investigate the causal associations between dried fruit intake and DNAm. METHODS: We performed two-sample Mendelian randomization (MR) using the IEU Open GWAS database aggregated data. Forty-three single nucleotide polymorphisms (SNPs) associated with dried fruit intake as instrumental variables (IVs) were selected as exposure. DNAm outcomes include Gran (estimated granulocyte proportions); AgeAccelGrim(GrimAge acceleration); Hannum (Hannum age acceleration); IEAA(Intrinsic epigenetic age acceleration), AgeAccelPheno( PhenoAge acceleration), and DNAmPAIadjAge (DNAm-estimated plasminogen activator inhibitor-1 levels). We used the MR pleiotropy residual sum and outlier test (MRPRESSO) and Radial-MR test to identify any level of multi-effect outliers and assessed the causal effect estimates(after removing outliers). The primary causal effects were estimated using inverse-variance weighted (IVW) method and undertook sensitivity analyses using MR methods robust to horizontal pleiotropy.The direct effects of dried fruit intake on DNAm were estimated using multivariable mendelian randomization (MVMR). RESULTS: Leveraging two-sample MR analysis, we observed statistically significant associations between dried fruit intake with a lower AgeAccelGrim(ß=-1.365, 95% confidence intervals [CI] -2.266 to -0.464, PIVW=2.985×10-3) and AgeAccelPheno (ß= -1.933, 95% CI -3.068 to -0.798, PIVW=8.371×10-4). By contrast, the effects level on Gran (ß=0.008, PIVW=0.430), Hannum(ß=-0.430, PIVW=0.357), IEAA(ß=-0.184, PIVW=0.700), and DNAmPAIadjAge (ß=-1.861, PIVW=0.093) were not statistically significant. MVMR results adjusting for the potential effects of confounders showed that the causal relationship between dried fruit intake and AgeAccelGrim(ß= -1.315, 95% CI -2.373 to -0.258, PIVW=1.480×10-2) and AgeAccelPheno(ß= -1.595, 95% CI -2.987 to -0.202, PIVW=2.483×10-2) persisted. No significant horizontal polymorphism was found in the sensitivity analysis. CONCLUSION: Our MR study suggested that increased dried fruit intake is associated with slower AgeAccelGrim and AgeAccelPheno. It can providing a promising avenue for exploring the beneficial effects of dried fruit intake on lifespan extension.
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Metilación de ADN , Frutas , Humanos , Bases de Datos Factuales , Frutas/genética , Granisetrón , Análisis de la Aleatorización Mendeliana , Polimorfismo de Nucleótido SimpleRESUMEN
Objective: To explore the value of cardiac magnetic resonance imaging (CMR) in the risk stratification of hypertrophic cardiomyopathy (HCM). Methods: HCM patients who underwent CMR examination in Fuwai Hospital between March 2012 and May 2013 were retrospectively enrolled. Baseline clinical and CMR data were collected and patient follow-up was performed using telephone contact and medical record. The primary composite endpoint was sudden cardiac death (SCD) or and equivalent event. The secondary composite endpoint was all-cause death and heart transplant. Patients were divided into SCD and non-SCD groups. Cox regression was used to explore risk factors of adverse events. Receiver operating characteristic (ROC) curve analysis was used to assess the performance and the optimal cut-off of late gadolinium enhancement percentage (LGE%) for the prediction of endpoints. Kaplan-Meier and log-rank tests were used to compare survival differences between groups. Results: A total of 442 patients were enrolled. Mean age was (48.5±12.4) years and 143(32.4%) were female. At (7.6±2.5) years of follow-up, 30 (6.8%) patients met the primary endpoint including 23 SCD and 7 SCD equivalent events, and 36 (8.1%) patients met the secondary endpoint including 33 all-cause death and 3 heart transplant. In multivariate Cox regression, syncope(HR=4.531, 95%CI 2.033-10.099, P<0.001), LGE% (HR=1.075, 95%CI 1.032-1.120, P=0.001) and left ventricular ejection fraction (LVEF) (HR=0.956, 95%CI 0.923-0.991, P=0.013) were independent risk factors for primary endpoint; Age (HR=1.032, 95%CI 1.001-1.064, P=0.046), atrial fibrillation (HR=2.977, 95%CI 1.446-6.131, P=0.003),LGE% (HR=1.075, 95%CI 1.035-1.116, P<0.001) and LVEF (HR=0.968, 95%CI 0.937-1.000, P=0.047) were independent risk factors for secondary endpoint. ROC curve showed the optimal LGE% cut-offs were 5.1% and 5.8% for the prediction of primary and secondary endpoint, respectively. Patients were further divided into LGE%=0, 0Asunto(s)
Cardiomiopatía Hipertrófica
, Medios de Contraste
, Humanos
, Femenino
, Adulto
, Persona de Mediana Edad
, Masculino
, Estudios Retrospectivos
, Volumen Sistólico
, Gadolinio
, Función Ventricular Izquierda
, Imagen por Resonancia Magnética
, Cardiomiopatía Hipertrófica/diagnóstico por imagen
, Muerte Súbita Cardíaca
, Medición de Riesgo
RESUMEN
Objective: To summarize the clinical and imaging features of linear scleroderma en coup de saber (LSCS) with central nervous system involvement in children. Methods: The clinical data(clinical manifestations and imaging features) of 6 children diagnosed with LSCS with central nervous system involvement who were admitted to Beijing Children's Hospital Affiliated to Capital Medical University from May 2019 to November 2021 were retrospectively analyzed. Results: The 6 patients were all female, aged 6.8 (3.3, 11.0) years at the time of diagnosis, and aged 3.0 (1.7, 4.1) years at the time of discovery of facial skin lesions. Facial skin lesions appeared before neurological symptoms in 5 cases, and neurological symptoms appeared 2 months before skin lesions in 1 case. All the patients had "sword wound" skin lesions on the forehead with alopecia. Neurological manifestations included epileptic seizures in 6 cases, focal neurological defects in 5 cases, and headaches in 2 cases. The intracranial lesions were all ipsilateral to the skin lesions. The magnetic resonance imaging (MRI) of 6 cases showed abnormal signals mainly involving white matter in 1 hemisphere, and 3 cases showed local encephalomalacia. The scattered low signal was observed in 5 cases on susceptibility weighted imaging. Localized brain parenchyma or leptomeninges enhancement was seen on Gadolinium-enhanced sequences in 5 cases. Scattered foci of calcification on the affected side were seen on cranial CT in 4 cases. Skin biopsy was performed in 2 cases. Part of the lesion of the brain was removed in 1 case, and the pathological findings suggested small vasculitis, which was consistent with skin pathological changes. All patients received symptomatic treatment with antiepileptic drugs. Oral prednisone combined with methotrexate was given in 4 cases, and 1 case was given oral prednisone only. One case was presumed to be in the resting stage of the disease due to significant cerebral atrophy in half of the brain, and only antiepileptic drugs were added. The patients were followed up for 6-36 months. The skin lesions of scleroderma and alopecia did not progress in 5 cases, and hemifacial atrophy was developed in 1 case, which was considered to be combined with Parry-Romberg syndrome. The seizures were controlled in 4 cases. One case had reduced seizure frequency but left hemiplegia. One patient still had intractable epilepsy and paroxysmal headache. Conclusions: LSCS with central nervous system involvement is more common in girls, with seizures and neurological defects as the main manifestations. Intracranial lesions are mostly ipsilateral to the skin lesions. Cerebral microbleeds, calcification, and encephalomalacia foci are common, and the pathological changes in skin and intracranial lesions are consistent with small-vessel vasculitis. Prednisone combined with methotrexate treatment has shown some efficacy, but some children remain with refractory epilepsy and neurological deficit symptoms.
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Calcinosis , Epilepsia Refractaria , Encefalomalacia , Esclerodermia Localizada , Niño , Humanos , Femenino , Anticonvulsivantes , Metotrexato , Prednisona , Estudios Retrospectivos , Convulsiones , Alopecia , Encéfalo , CefaleaRESUMEN
PURPOSE: Single-site laparoscopic percutaneous extraperitoneal ligation (SLPEL) for pediatric inguinal hernia has gained popularity worldwide. However, complications associated with extraperitoneal knotting are not rare. This study evaluated the effectiveness of a modified SLPEL (M-SLPEL) to decrease adverse events associated with ligation knotting by comparing it with two other methods: classical SLPEL (C-SLPEL) and intracorporeal purse-string suturing (IPS). METHODS: A multicenter retrospective comparative study was conducted among 5523 pediatric inguinal hernia patients. Cases were divided into three groups according to the surgical procedure: the M-SLPEL, C-SLPEL, and IPS groups. Data describing the clinical characteristics, operative time, and complications were collected. RESULTS: All procedures were performed uneventfully. There were no significant differences in the age at operation (mean 2.62 ± 1.38 years). The operative time was shorter in the M-SLPEL group both for unilateral hernias (12.5 ± 1.8 min in C-SLPEL, 11.7 ± 1.3 min in M-SLPEL, and 17.6 ± 2.9 min in IPS) and for bilateral hernias (15.1 ± 2.1 min, 14.6 ± 1.7 min, and 23.9 ± 2.3 min, respectively). The overall incidence of adverse events in the inguinal region was 0% for M-SLPEL, 2.2% for C-SLPEL, and 0.5% for IPS. All patients were followed up for 12-93 months (mean 54 months). Recurrence occurred in 8 cases in the C-SLPEL group, 1 case in the M-SLPEL group, and 8 cases in the IPS group, with no significance between groups. No scrotal hematoma, testicular atrophy, or iatrogenic cryptorchidism occurred in any group. CONCLUSION: The M-SLPEL procedure has time-consumption efficiency equivalent to that of C-SLPEL and even fewer adverse events in the inguinal region than IPS and C-SLPEL.
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Hernia Inguinal , Laparoscopía , Masculino , Niño , Humanos , Lactante , Preescolar , Hernia Inguinal/cirugía , Hernia Inguinal/etiología , Herniorrafia/efectos adversos , Herniorrafia/métodos , Estudios Retrospectivos , Laparoscopía/efectos adversos , Laparoscopía/métodos , Tempo Operativo , Resultado del Tratamiento , RecurrenciaRESUMEN
BACKGROUND: The current global coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown limited responses to medical treatments. AIMS: To observe the effect of combination treatment of giammonium glycyrrhizinate and vitamin C (DV) on the prognoses of patients with COVID-19. METHODS: This retrospective observational study recruited 207 COVID-19 patients from Tongji Hospital, patients were assigned to DV and non-DV groups on the basis of the DV treatment. To make the results more credible, a propensity score matching (PSM) approach was adopted at a 1:3 ratio to determine the participants. Logistic analysis was used to assess the effect of DV therapy in the progress of COVID-19. RESULTS: In the DV group, the new-onset incidence rate of acute respiratory distress syndrome (ARDS) after admission was clearly lower than that in the non-DV group (DV vs. non-DV groups, 15.2% vs. 35.7%; P = 0.002). Compared with the non-DV group, the DV group showed fewer new onset of complications (such as ARDS, acute liver injury and acute myocardial injury) (DV vs. non-DV groups, 19.6% vs. 46.1%; P = 0.000). Moreover, DG+VC may help to recover the count of NK cells and decrease the level of sIL-2R. CONCLUSIONS: DG+VC might be a promising candidate for preventing the deterioration of COVID-19 patients, which is worthy to be studied in large and perspective cohort.
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COVID-19 , Ácido Ascórbico , Ácido Glicirrínico , Humanos , Estudios Retrospectivos , SARS-CoV-2RESUMEN
The quantum relaxation time of electrons in condensed matters is an important physical property, but its direct measurement has been elusive for a century. Here, we report a breakthrough that allows direct determination of quantum relaxation time at zero and non-zero frequencies using optical measurement. Through dielectric loss function, we connect bound electron effects to the physical parameters of plasma resonance and find an extra term of quantum relaxation time from inelastic scattering between bound electrons and conduction electrons at non-zero frequencies. We demonstrate here that the frequency-dependent inelastic polarization effect of bound electrons is the dominant contribution to quantum relaxation time of conduction electrons at optical frequencies, and the elastic polarization effect of bound electrons also dramatically changes the plasma resonance frequency through effective screening to charge carriers.
RESUMEN
To analysis the treatment effectiveness of maxillofacial arteriovenous malformation (AVM) by means of temporary balloon block and percutaneous puncture sclerotherapy. The treatment outcomes of 20 patients with AVM of maxillofacial deformity, aged (26.8±3.0) 18-36 years, from Dec 2012 to Dec 2019 were collected and retrospectively analyzed. All patients had been diagnosed AVM by digital substraction angiography (DSA). All the cases were treated by using balloons to temporary block responsible artery of the AVM in order to change the high-flow malformations into low-flow venous malformation. Then injection of polyethylene foam cinnamyl alcohol was conducted via percutaneous puncturing for hardening the vascular malformation. Comparing the symptoms and imaging changes before treatment with those 1-6 months after treatment according to Achauer curative effect evaluation standard. Totally 60% (12/20) of the cases were type â ¡a AVM, and their treatments were effective. However, the treatment effects of type â ¢b and type â £ patients were relatively poor. The clinical effective rate was 85% (17/20), and the clinical curative rate was 50% (10/20). No skin necrosis, organ damage and other serious complications were observed for the 20 patients. The AVM patients with a main supply artery treated by using a balloon artery temporary block to make high flow malformations into low-flow and followed by percutaneous puncture sclerotherapy, could get good curative effect. It seemed that this approach was safe and effective.
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Malformaciones Arteriovenosas , Malformaciones Vasculares , Malformaciones Arteriovenosas/terapia , Humanos , Punciones , Estudios Retrospectivos , Escleroterapia , Resultado del TratamientoRESUMEN
High-resolution single-shot nonrelativistic ultrafast electron microscopy (UEM) relies on adaptive optics to compress high-intensity bunches using radio frequency (RF) cavities. We present a comprehensive discussion of the analytic approaches available to characterize bunch dynamics as an electron bunch goes through a longitudinal focal point after an RF cavity where space charge effects can be large. Methods drawn from the Coulomb explosion literature, the accelerator physics literature, and the analytic Gaussian model developed for UEM are compared, utilized, and extended in some cases. In particular the longitudinal focus may occur in two different regimes, a bounce-back regime and a crossover regime; and we characterize the critical point separating these regimes in the zero-emittance model. Results from N-particle simulations using efficient multipole methods are compared to the theoretical models revealing features requiring extensions of the analytic approaches; and in particular mechanisms for emittance growth and transfer are discussed.
RESUMEN
OBJECTIVE: Depletion of islet ß cells plays a crucial role in the onset of diabetes mellitus. Cell autophagy, as a self-healing process, contributes to maintaining metabolic homeostasis and can protect islet ß cells from apoptosis upon starvation or high glucose stress. However, the underlying regulatory network of the autophagic process in islet ß cells has not been fully explored. MATERIALS AND METHODS: Murine ß-TC3 cells treated with different concentrations of glucose, and wild-type or the Ser484 mutant human cell division cycle gene 14A (hCDC14A) was transfected. Cell viability, proliferation and autophagy as well as islet secretion were studied. The mTOR and AMPK signaling pathways were investigated by western blots. Zipper-interacting protein kinase was studied using mass spectrometry and immunoprecipitation. RESULTS: Overexpression of wild-type hCDC14A, but not the Ser484 mutant hCDC14A, promoted cell viability, proliferation and autophagy accompanied by enhanced islet secretion and reduced cell apoptosis via mTOR pathway inhibition as well AMPK pathway activation in ß-TC3 cells and vice versa. Furthermore, Zipper-interacting protein kinase (ZIPK), also known as DAPK3, was found to interact with hCDC14A primarily for Ser484 phosphorylation, and ZIPK knockdown could affect the phosphorylation of hCDC14A and weaken cell death or cell cycle modulation. CONCLUSIONS: Taken together, our results may provide new insight into the role of hCDC14A in the autophagy of islet ß cells and suggest the potential therapeutic value of hCDC14A phosphorylation in the prevention and treatment of diabetes.
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Autofagia , Proteínas Quinasas Asociadas a Muerte Celular/metabolismo , Islotes Pancreáticos/metabolismo , Proteínas Tirosina Fosfatasas/metabolismo , Animales , Autofagia/efectos de los fármacos , Línea Celular , Proteínas Quinasas Asociadas a Muerte Celular/genética , Glucosa/farmacología , Islotes Pancreáticos/efectos de los fármacos , Ratones , Fosforilación/efectos de los fármacos , Proteínas Tirosina Fosfatasas/genéticaRESUMEN
In general, the application conditions of linear regression models could be met after the natural logarithmic transformation of data. From the practical perspective, this paper introduced the linear regression models with natural logarithmic transformation of independent variable, dependent variable, and both independent and dependent variables in detail. The paper illustrated why the equation and coefficients could not be directly explained after the natural logarithmic transformation of data. The percentage changes of X and/or Y were applied to elaborate the principle and method for the explanation of the equation and coefficients. Three examples were used to fit simple linear models with natural logarithmic transformation of independent, dependent, and both independent and dependent variables and the results of theses models were explained in detail.
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Modelos Lineales , Análisis MultivarianteRESUMEN
Objective: To survey the children under 7 years of age in nine cities of China for a better understanding of the current situation of childhood stunting. Methods: According to a stratified cluster sampling design, a cross-sectional survey on children under 7 years of age was carried out in 9 cities (Beijing, Harbin and Xi'an in northern China; Shanghai, Nanjing and Wuhan in central China; and Guangzhou, Fuzhou and Kunming in southern China) from June to November in 2016. A total of 110 499 children were recruited. Height of children was evaluated using the growth standards for Chinese children (2009 edition) .Children with height less than the 3rd percentile of the growth standards were considered as stunting, and children with height between the 3rd and 10th percentiles of the growth standards were considered as relatively short stature. Chi-square test was used for comparison between data of boys and girls, urban and suburban, as well as among different ages and regions. Results: Totally 113 084 children under 7 years of age should be investigated and actually 110 499 children were investigated, with a rate of 97.7%. The prevalence of stunting was 1.9% (2 141/110 499) among all the children. The prevalence of stunting in urban children (1.6%, 904/55 524) was lower than that in suburban children (2.3%, 1 237/54 975, χ(2)=56.246, P<0.01). The gender difference in stunting prevalence was not statistically significant (1.9% (1 121/57 921) in boys and 1.9% (1 020/52 578) in girls, χ(2)=0.003, P=0.965). The prevalence of stunting decreased with age for children younger than 3 years, from 1.8% (312/17 080) in 0-<1 year of age group to 1.2% (168/13 740) in 2-<3 years of age group, but increased to 2.2% (240/11 073) at 6-<7 years group. Comparison among different regions showed that the stunting prevalence in southern region was higher than those in the central and northern regions (0.9% (193/20 374) in northern urban, 0.8% (154/18 486) in central urban, and 3.3% (557/16 664) in southern urban children), showing a statistical significance (χ(2)=437.736, P<0.01); 1.1% (241/21 924) in northern suburban, 1.4% (227/16 775) in central suburban and 4.7% (769/16 276) in southern suburban children, showing a statistical significance (χ(2)=646.533, P<0.01). In urban areas, the difference between the central and northern regions showed no statistical significance (χ(2)=1.429, P=0.232) and the stunting prevalence of central Chinese children was slightly higher than that of northern Chinese children in suburban areas (χ(2)=5.130, P=0.024). Among the nine cities, the stunting prevalence of Guangzhou (6.1%, 613/10 019) was higher than those of other cities (χ(2)=1 559.64, P<0.01). Among the stunting children, 78.4% (1 679/2 141) were classified as borderline or mild and only 7.2% (154/2 141) were classified as severe. The prevalence of relatively short stature was 5.2% (5 721/110 499). Conclusions: The prevalence of stunting among children under 7 years of age in nine cities of China is low and most of the stunting children were classified as mild; the prevalence of stunting in suburban children is higher than that in urban children; the gender difference show no statistical significance; and the prevalence of stunting in southern Chinese children is higher than those in central and northern Chinese children.