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BACKGROUND: Percutaneous nephrostomy (PCN) and Double J stenting (DJS) are the 2 main treatment options of ureteral obstruction. We evaluate which of these 2 methods is superior concerning the course of procedure, postoperative complication and quality of life. METHODS: A detailed review of electronic databases including PubMed, Embase, Cochrane Library, China Biology Medicine disc, China National Knowledge Infrastructure up to February 21st, 2021 was searched. Continuous data were evaluated using mean difference (MD) with 95% confidence interval (CI), while nominal data were analyzed by risk ratio (RR) with 95% CI. Meanwhile, we performed the subgroup analysis based on study design, disease type, sample size, sepsis, DJ diameter, nephrostomy diameter, anesthesia type and guidance under X-ray or ultrasound. RESULTS: There were 18 previous studies included in current study. As a result, we found that there were significant differences in fluoroscopy time (MDâ =â 0.31; 95% CI, 0.14-0.48, Pâ <â .001) and hospital stay (MDâ =â 1.23; 95% CI, 0.60-1.85, Pâ <â .001). However, no statistic difference was detected in operative time (MDâ =â 5.40; 95% CI, -1.78 to 12.58, Pâ =â .140) between the paired groups. Although DJS showed a higher rate of postoperative complications (25.19% vs 17.61%), there was no significant difference in the incidence of complications following DJS and PCN (RRâ =â 0.92; 95% CI, 0.60-1.43; Pâ =â .720). Based on the EuroQol analysis, the 2 main treatment options had different impacts on quality of life. The pooled results showed that PCN patients reported more difficulties in self-care compared to DJS patients (RRâ =â 3.07; 95% CI, 1.32-7.14; Pâ =â .009). CONCLUSIONS: DJS is a safe and better method of temporary urinary diversion than PCN for management of ureteral obstruction with shorter fluoroscopy time and hospital stay. As for quality of life, patients receiving PCN had a distinct difficulty in self-care compared to those receiving DJS. However, these 2 treatment options often depends on the individual situation.
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Nefrostomía Percutánea , Uréter , Obstrucción Ureteral , Humanos , Nefrostomía Percutánea/efectos adversos , Nefrostomía Percutánea/métodos , Complicaciones Posoperatorias/epidemiología , Calidad de Vida , Uréter/cirugía , Obstrucción Ureteral/cirugía , Obstrucción Ureteral/etiologíaRESUMEN
OBJECTIVE: To study the effects of staged Duckett urethroplasty and Byars reconstruction in the treatment of severe hypospadias with dysplastic glans. METHODS: We retrospectively analyzed the clinical data on 57 cases of severe hypospadias with dysplastic glans treated by two-stage Duckett urethroplasty or Byars reconstruction from September 2015 to May 2020. At stage-â treatment, the patients were aged from 5 to 47 (mean 21) months, the diameter of the glans less than 1.4 cm, and the interval between the two stages from 6 to 41 (mean 14) months. The patients underwent Duckett urethroplasty, distal in stage â and proximal in stage â ¡ (group A, n = 25) or Byars reconstruction with the urethral plate in stage â and Duplay urethroplasty in stage â ¡ (group B, n = 32). Postoperative follow-up lasted 12ï¼56 (mean 35) months. RESULTS: After stage â ¡ surgery, penile straightening and smooth appearance of the graft were achieved in all the patients. Six cases of postoperative complications (24%) were observed in group A, including 4 cases of urinary fistula, 1 case of glans dehiscence, 1 case of urethral diverticulum and 1 case of urethral stricture, while 14 cases (43.8%) were observed in group B, including 9 cases of urinary fistula, 9 cases of glans dehiscence and 2 cases of urethral diverticulum, with a remarkably lower incidence rate of glans dehiscence in group A than in B (P = 0.043), but no statistically significant difference in the other observations between the two groups (P > 0.05). CONCLUSION: Both staged strategies of Duckett urethroplasty and Byars reconstruction can be used for the treatment of severe hypospadias with dysplastic glans, but the latter may result in a higher incidence rate of glans dehiscence postoperatively and bring more difficulties to subsequent repair.
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Divertículo , Hipospadias , Procedimientos de Cirugía Plástica , Fístula Urinaria , Masculino , Humanos , Lactante , Hipospadias/cirugía , Hipospadias/etiología , Estudios Retrospectivos , Resultado del Tratamiento , Procedimientos Quirúrgicos Urológicos Masculinos , Uretra/cirugía , Divertículo/complicaciones , Divertículo/cirugíaRESUMEN
Objectives: The objective of the study is to investigate the feasibility and efficacy of urethroplasty with a Buck's fascia integral-covering technique (BFIC) to wrap and restore the normal anatomical structure of the penis in one-stage hypospadias surgery. Methods: One-stage surgeries for hypospadias management were performed using BFIC from January 2016 to September 2020 at four high-volume medical centers in China. The technique integrates Buck's fascia with glans wings to mobilize and wrap the urethra and restore penile anatomical relationships. The clinical data, postoperative follow-up data, and complications were recorded, and the results were analyzed. Results: A total of 1,386 patients were included in the study: 1,260 cases of primary hypospadias and 126 cases of re-operations; distal in 382 cases (27.6%), mid-shaft in 639 (46.1%), proximal in 365 (26.3%); tubularized incised plate (TIP) in 748 cases, inlay-graft in 124, onlay-graft in 49, Mathieu in 28, free-tube graft urethroplasty in 406, and 31 of hybrid procedures. One thousand one hundred forty-two patients (82.4%) were found to have penile curvature (>10°) after artificial erection and all corrected by dorsal plication/s or transection of the urethra plate (UP) simultaneously. The median followed-up time was 27 months (6-62). A total of 143 (10.3%) complications were recorded: 114 (9.0%) in the primary operations and 29 (23%) in the re-operations, 15 (3.9%) in distal hypospadias, 61 (9.5%) in mid-shaft, and 67 (18.4%) in proximal. The complication rate in UP preservation and transection was 10.1 and 10.8%, respectively. Of all case complications, there were 73 (5.2%) of fistula, 10 (0.6%) of dehiscence, 22 (1.6%) of meatal stenosis, 21 (1.5%) of stricture, 6 (0.7%) of diverticulum, and resident curvature in 11 cases (1.2%). The overall complication rate in TIP and free-tube procedure was 9.8 and 9.9%, respectively, and fistula occurred in primary TIP of 33 cases (4.9%). Conclusions: Buck's fascia with the glans can be used as an integral covering technique in one-stage distal to proximal hypospadias and primary or re-operative hypospadias repair. It is safe, feasible, and effective for the repair of hypospadias.
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BACKGROUND: It is well known that liposome-based delivery of cytotoxic chemotherapeutics has been proposed as a putative strategy to enhance drug tolerability and efficacy compared to the conventional chemotherapy. However, its potential effect on improving prognosis remains largely unknown. The current meta-analysis is to explore the prognosis of cancer patients undergoing liposomal doxorubicin-based chemotherapy. METHODS: A detailed review of English and Chinese literature was conducted up to March 21, 2020. We evaluate its possible correlations using hazard ratios (HRs) with 95% confidence intervals (CIs). The pooled data were calculated by STATA software and Review Manager 5.3 software. RESULTS: Consequently, 26 studies including 7943 patients were satisfied in current analysis. There were no significant differences between liposomal and conventional chemotherapy in OS (HRâ=â0.98, 95%CI: 0.93-1.04, Pâ=â.544) and PFS (HRâ=â1.00, 95%CI: 0.92-1.10, Pâ=â.945). Likewise, subgroup-analysis regarding country, cancer type, and sample sizes also showed the similar results of the 2 paired groups. CONCLUSION: Taken together, our finding has demonstrated that there was no association of undergoing liposomal doxorubicin-based chemotherapy with cancer prognosis. However, detailed and further studies are needed to confirm our conclusion.
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Antibióticos Antineoplásicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Doxorrubicina/análogos & derivados , Neoplasias/tratamiento farmacológico , Antibióticos Antineoplásicos/administración & dosificación , Antibióticos Antineoplásicos/efectos adversos , Doxorrubicina/administración & dosificación , Doxorrubicina/efectos adversos , Doxorrubicina/uso terapéutico , Humanos , Estudios Multicéntricos como Asunto , Polietilenglicoles/administración & dosificación , Polietilenglicoles/efectos adversos , Polietilenglicoles/uso terapéutico , Modelos de Riesgos Proporcionales , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
Studies about medical care needs for home healthcare (HHC) previously focused on disease patterns but not gender and income differences. We used the Taiwan National Health Research Insurance Database from 1997 to 2013 to examine trends in medical care needs for patients who received HHC, and the gender and income gaps in medical care needs, which were represented by resource utilization groups (RUG). We aimed to clarify three questions: 1. Are women at a higher level of medical care needs for HHC than men, 2. Does income relate to medical care needs? 3. Is the interaction term (gender and income) related to the likelihood of medical care needs? Results showed that the highest level of medical care need in HHC was reducing whereas the basic levels of medical care need for HHC are climbing over time in Taiwan during 1998 and 2013. The percentages of women with income-dependent status in RUG1 to RUG4 are 26.43%, 26.24%, 30.68%, and 32.07%, respectively. Women were more likely to have higher medical care needs than men (RUG 3: odds ratio, OR = 1.17, 95% confidence interval, CI = 1.10-1.25; RUG4: OR = 1.13, 95% CI = 1.06-1.22) in multivariates regression test. Compared to the patients with the high-income status, patients with the income-dependent status were more likely to receive RUG3 (OR = 2.34, 95% CI = 1.77-3.09) and RUG4 (OR = 1.98, 95% CI = 1.44-2.71). The results are consistent with the perspectives of fundamental causes of disease and feminization of poverty theory, implying gender and income inequalities in medical care needs. Policymakers should increase public spending for delivering home-based integrated care resources, especially for women with lower income, to reduce the double burden of female poverty at the higher levels of medical care needs for HHC.
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Atención a la Salud/tendencias , Servicios de Atención de Salud a Domicilio/tendencias , Renta , Factores Sexuales , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores Socioeconómicos , TaiwánRESUMEN
BACKGROUND: For people with dementia, burdensome transitions may indicate poorer-quality end-of-life care. Little is known regarding the association between home healthcare (HHC) and these burdensome transitions. We aimed to investigate the impact of HHC on transitions and hospital/intensive care unit (ICU) utilisation nearing the end-of-life for people with dementia at a national level. METHODS: A nested case-control analysis was applied in a retrospective cohort study using a nationwide electronic records database. We included people with new dementia diagnoses who died during 2002-2013 in whole population data from the universal healthcare system in Taiwan. Burdensome transitions were defined as multiple hospitalisations in the last 90 days (early transitions, ET) or any hospitalisation or emergency room visit in the last three days of life (late transitions, LT). People with (cases) and without (controls) burdensome transitions were matched on a ratio of 1:2. We performed conditional logistic regression with stratified analyses to estimate the adjusted odds ratio (OR) and 95% confidence interval (CI) of the risks of transitions. RESULTS: Among 150,125 people with new dementia diagnoses, 61,399 died during follow-up, and 31.1% had burdensome transitions (50% were early and 50% late). People with ET had the highest frequency of admissions and longer stays in hospital/ICU during their last year of life, while people with LT had fewer hospital/ICU utilisation than people without end-of-life transitions. Receiving HHC was associated with an increased risk of ET (OR = 1.14, 95 % CI: 1.08-1.21) but a decreased risk of LT (OR = 0.89, 95 % CI 0.83-0.94). In the people receiving HHC, however, those who received longer duration (e.g., OR = 0.50, 95 % CI: 0.42-0.60, >365 versus ≤30 days) or more frequent HHC or HHC delivered closer to the time of death were associated with a remarkably lower risk of ET. CONCLUSIONS: HHC has differential effects on early and late transitions. Characteristics of HHC such as better continuity or interdisciplinary coordination may reduce the risk of transitions at the end-of-life. We need further studies to understand the longitudinal effects of HHC and its synergy with palliative care, as well as the key components of HHC that achieve better end-of-life outcomes.
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Atención a la Salud , Demencia , Cuidado Terminal , Estudios de Cohortes , Atención a la Salud/estadística & datos numéricos , Demencia/epidemiología , Hospitalización/estadística & datos numéricos , Humanos , Estudios Retrospectivos , Taiwán/epidemiología , Cuidado Terminal/estadística & datos numéricosRESUMEN
OBJECTIVE: To summarize the experience in the surgical treatment of hypospadias by analyzing the operation features and clinical effects of two different routes for transferring the pedicled preputial island flap. METHODS: This retrospective study included 122 cases of hypospadias treated by transferring the pedicled preputial island flap, 80 from one side of the penis (the control group) and the other 42 through the middle orifice of the vascular pedicle (the observation group). We recorded the intra- and postoperative data and compared them between the two groups. RESULTS: The operation time was significantly longer in the observation group than in the control (ï¼»164.43 ± 25.03ï¼½ vs ï¼»134.71 ± 32.37ï¼½ min, P < 0.01), but the catheter-indwelling time was dramatically shorter in the former than in the latter group (ï¼»2.93 ± 0.97ï¼½ vs ï¼»3.68 ± 0.73ï¼½ wk, P < 0.01). There was no statistically significant difference in the length of the reconstructed urethra between the two groups (ï¼»2.86 ± 0.71ï¼½ vs ï¼»2.83 ± 0.82ï¼½ cm, P = 0.863). A 6- to 12-month follow-up showed a significantly lower incidence of postoperative complications in the observation than in the control group (9.52% vs 25.00%, P < 0.05). CONCLUSIONS: Transferring the pedicled preputial island flap through the middle orifice of the vascular pedicle, though taking a longer time than that from one side of the penis, has the advantages of a shorter catheter-indwelling time and a lower incidence rate of postoperative complications, and therefore deserves wide clinical application.
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Hipospadias , Pene/cirugía , Colgajos Quirúrgicos/trasplante , Uretra/cirugía , Niño , Prepucio/cirugía , Humanos , Hipospadias/cirugía , Masculino , Estudios RetrospectivosRESUMEN
BACKGROUND: Previous studies examining the safety and efficacy of Q-value-guided laser-assisted in situ keratomileusis (LASIK) for treating myopia have yielded inconsistent results. We, therefore, performed a meta-analysis to clarify this issue METHODS:: Various databases were conducted up to November 21, 2018. All randomized controlled trials and cohorts that compared Q-value-guided LASIK with standard LASIK were selected. Mean differences (MDs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the strength of the correlations. Additionally, different subgroup analyses and publication bias tests were performed. Data were extracted including the number of postoperative uncorrected visual acuity (UCVA) of 20/20 or better, postoperative UCVA, preoperative and postoperative Q-value, postoperative refractive spherical equivalent (SE), the number of postoperative SE within ±0.5D, higher order aberration (HOA), coma-like aberration and spherical-like aberration. RESULTS: A total of seventeen studies with 2640 patients and 3,358 eyes were included. It has been shown that postoperative Q-value (MDâ=â-0.42; 95% CI: -0.64, -0.21; Pâ<â.001), HOA (MDâ=â-0.14; 95% CI: -0.23, -0.06; Pâ=â.001), spherical-like aberration (MDâ=â-0.19; 95% CI: -0.32, -0.06; Pâ=â.004) rather than postoperative UCVA (MDâ=â0.04; 95% CI: 0.01, 0.07; Pâ=â.012) were significantly better in the Q-value-guided LASIK than standard LASIK. However, the pooled results revealed that no significant differences were found between the 2 paired groups of postoperative UCVA of 20/20 or better (ORâ=â1.09; 95% CI: 0.62, 1.92; Pâ=â.763), preoperative Q-value (MDâ=â-0.00; 95% CI: -0.02, 0.02; Pâ=â.922), postoperative refractive SE (MDâ=â0.08; 95% CI: -0.09, 0.25; Pâ=â.336), coma-like aberration (horizontal: MDâ=â-0.00; 95% CI: -0.03, 0.03; Pâ=â.966; vertical: MDâ=â-0.01; 95% CI: -0.03, 0.01; Pâ=â.263) and postoperative SE within ±0.5 D (ORâ=â1.06; 95% CI: 0.48, 2.33; Pâ=â.886). Likewise, similar results were detected in some corresponding subgroups. CONCLUSION: Q-value-guided LASIK is a safe, effective and predictable surgical option for treating myopia, especially showing superiority over standard LASIK in postoperative Q-value, HOA and spherical-like aberration. However, more detailed studies are required to confirm our conclusions in advanced researches.
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Queratomileusis por Láser In Situ/métodos , Miopía/cirugía , Humanos , Pruebas de Visión , Agudeza VisualRESUMEN
BACKGROUND: The use of home health care (HHC) is increasing worldwide. This may have an impact not only on patients and their caregivers' health but on care resource utilization and costs. We lack information on the impact of HHC on the broader dimensions of health status and care resource utilization. More understanding of the longitudinal HHC impact on HHC patients and caregivers is also needed. Moreover, we know little about the synergy between HHC and social care. Therefore, the present study aims to observe longitudinal changes in health, care resource utilization and costs and caregiving burden among HHC recipients and their caregivers in Taiwan. METHODS: A prospective cohort study "Home-based Longitudinal Investigation of the Multidisciplinary Team Integrated Care (HOLISTIC)" will be conducted and 600 eligible patient-caregiver dyads will be recruited and followed with comprehensive quantitative assessments during six home investigations over two years. The measurements include physical function, psychological health, cognitive function, wellbeing, shared decision making and advance care planning, palliative care and quality of dying, caregiving burden, continuity and coordination of care, care resource utilization, and costs. DISCUSSION: The HOLISTIC study offers the opportunity to comprehensively understand longitudinal changes in health conditions, care resource utilization and costs and caregiving burden among HHC patients and caregivers. It will provide new insights for clinical practitioners and policymakers. TRIAL REGISTRATION: ClinicalTrials.gov Identifier is NCT04250103 which has been registered on 31st January 2020.
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Cuidadores , Prestación Integrada de Atención de Salud , Estudios de Cohortes , Humanos , Grupo de Atención al Paciente , Estudios Prospectivos , TaiwánRESUMEN
Mushroom poisoning is a serious food safety issue in China. However, there is insufficient information on many poisoning incidents, including mushroom species and their clinical manifestations, diagnosis, treatments and toxins. Detailed epidemiological investigation was conducted after the occurrence of a mushroom poisoning incident resulting in typical muscarinic syndrome in Ningxia, China. The suspected mushroom species was identified based on morphological and phylogenetic analyses. Muscarine was detected using ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). On September 2, 2019, two patients exhibited typical muscarinic syndrome after consuming wild mushrooms. The clinical manifestations included chills, sweating, salivation and diarrhoea; the incubation period was approximately 2 h. Treatments, including anti-inflammatory, detoxification and nutritional support, were remedial. Full recovery ensued within 24 h. The specimen was identified as Inocybe serotina, and its muscarine content was 324.0 ± 62.4 mg/kg (k = 2, p = 95%). Two patients were poisoned via stimulation of their parasympathetic nervous system due to mistaken consumption of muscarine-containing I. serotina. They fully recovered with supportive treatments. To our knowledge, this is the first case report of I. serotina poisoning worldwide and is the first record of this species in China. Further, a method for muscarine detection was established using UPLC-MS/MS.
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Muscarina/análisis , Intoxicación por Setas/diagnóstico , Agaricales/química , China , Humanos , Intoxicación por Setas/metabolismo , Toxinas BiológicasRESUMEN
BACKGROUND: To investigate the compliance to self-monitoring of blood glucose (SMBG) among patients with type 2 diabetes mellitus (T2DM) and its influential factors. METHODS: The real-world SMBG use over 90 days among 415 T2DM patients were recorded by using a blood glucose monitoring platform (TDF-I, Tencent, China). Clinical features including age, sex, duration of diabetes, insulin treatment or not, and use of oral antidiabetic drugs were collected. Poor compliance was defined as the average frequency of weekly SMBG use over 90 days was below the criteria established by the physicians, and otherwise the patients were regarded as with good compliance. Factors affecting the SMBG compliance were analyzed by using independent sample t-test, Mann-Whitney U test, and multivariate logistic regression analysis. RESULTS: Only 57.6% of patients in the study cohort had good compliance to SMBG. Multivariate logistic regression models showed that only the duration of T2DM and the use of oral antidiabetic agents were independently associated with SMBG compliance; more specifically, patients with longer course of disease had poorer SMBG compliance, and those had used oral antidiabetic agents had poorer SMBG compliance. CONCLUSIONS: SMBG compliance in T2DM patients needs to be further improved. For patients with a longer course of disease and/or under oral antidiabetic medication, interventions such as patient education should be adopted to increase the SMBG compliance.
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The human ether-à-go-go related gene (hERG) potassium channel is an obligatory anti-target for drug development on account of its essential role in cardiac repolarization and its close association with arrhythmia. Diverse drugs have been removed from the market owing to their inhibitory activity on the hERG channel and their contribution to acquired long QT syndrome (LQTS). Moreover, mutations that cause hERG channel dysfunction may induce congenital LQTS. Recently, an increasing number of biochemical and molecular mechanisms underlying hERG-associated LQTS have been reported. In fact, numerous potential biochemical and molecular rescue strategies are hidden within the biogenesis and regulating network. So far, rescue strategies of hERG channel dysfunction and LQTS mainly include activators, blockers, and molecules that interfere with specific links and other mechanisms. The aim of this review is to discuss the rescue strategies based on hERG channel toxicology from the biochemical and molecular perspectives.
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Canales de Potasio Éter-A-Go-Go/efectos de los fármacos , Síndrome de QT Prolongado/tratamiento farmacológico , Toxicología , Investigación Biomédica Traslacional , Animales , Canal de Potasio ERG1 , Canales de Potasio Éter-A-Go-Go/genética , Canales de Potasio Éter-A-Go-Go/metabolismo , Regulación de la Expresión Génica , Predisposición Genética a la Enfermedad , Humanos , Síndrome de QT Prolongado/inducido químicamente , Síndrome de QT Prolongado/genética , Síndrome de QT Prolongado/metabolismo , Síndrome de QT Prolongado/fisiopatología , Mutación , Fenotipo , Transporte de Proteínas , Medición de Riesgo , Transducción de Señal/efectos de los fármacosRESUMEN
Arsenic trioxide (As2O3) is used to treat acute promyelocytic leukemia. However, the cardiotoxicity of long QT syndrome restricts its clinical application. Previous studies showed that As2O3 can damage the human ether-a-go-go-related gene (hERG) current via disturbing its trafficking to cellular membrane. This study aimed to investigate whether the As2O3-insulted hERG channel can be rescued by resveratrol, a recognized cardioprotective agent. The whole-cell patch clamp technique was used to record the hERG current and action potential duration. Co-immunoprecipitation and Western blot assay were applied to determine the function of hERG-Hsp70/Hsp90 chaperone complexes and the expression alteration of protein-folding-related proteins, respectively. Compared with treatment of As2O3 alone, co-treatment with resveratrol successfully restored the current and surface expression of hERG and obviously shortened action potential duration in guinea pig ventricular myocytes. Further experiments demonstrate that resveratrol relieved As2O3-caused endoplasmic reticulum (ER) stress by restoring the function of hERG-Hsp70/Hsp90 chaperone complexes and downregulating the protein expression of ER chaperone proteins (calnexin and calreticulin) and activating transcription factor 6. In conclusion, resveratrol was able to rescue the trafficking deficiency and relieve the ER stress (ERS). Our findings suggest that resveratrol has a potential effect to alleviate the adverse effect of As2O3 on cardiotoxicity.
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Cardiotoxicidad/prevención & control , Estrés del Retículo Endoplásmico/efectos de los fármacos , Óxidos/toxicidad , Estilbenos/farmacología , Potenciales de Acción/efectos de los fármacos , Animales , Antineoplásicos/toxicidad , Trióxido de Arsénico , Arsenicales , Western Blotting , Cardiotónicos/farmacología , Cardiotoxicidad/etiología , Regulación hacia Abajo/efectos de los fármacos , Canal de Potasio ERG1 , Canales de Potasio Éter-A-Go-Go/deficiencia , Cobayas , Células HEK293 , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas HSP90 de Choque Térmico/metabolismo , Ventrículos Cardíacos/efectos de los fármacos , Ventrículos Cardíacos/metabolismo , Humanos , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Técnicas de Placa-Clamp , ResveratrolRESUMEN
In this paper, we present a new approach that is capable of fabricating nanochannels in a poly(methyl methacrylate) (PMMA) substrate. This method, which we call microchannel refill (MR), utilizes the refilling of glassy thermoplastics under thermal compression to reduce a microscopic channel to a nanochannel. It only has two main steps. First, a microchannel is fabricated in a PMMA substrate using normal hot embossing. Second, the microchannel is compressed under a certain temperature and pressure to obtain a nanochannel. We show that a nanochannel with a width as small as 132 nm (with a depth of 85 nm) can be easily produced by choosing the appropriate compression temperature, compression pressure, original microchannel width and original microchannel aspect ratio. Compared with most current nanochannel fabrication methods, MR is a quick, simple and cost-effective way to produce nanochannels in polymer substrates.
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Stomatal transpiration, which is an efficient way to carry water from the roots up to the leaves, can be described by "diameter-law". According to the law, the flow rate induced by micropore transpiration far exceeded that induced by macroscale evaporation, and it can be controlled by opening (or closing) some micropores. In this research, a bio-inspired micropump based on stomatal transpiration is presented. The micropump is composed of three layers: the top layer is a 93 µm-thick PVC (polyvinylchloride) film with a group of slit-like micropores; the second layer is a PMMA sheet with adhesives to join the other two layers together; the third layer is a microporous membrane. Using this pump, controllable flow rates of 0.13-3.74 µl min(-1) can be obtained. This micropump features high and adjustable flow-rates, simple structure and low fabrication cost. It can be used as a "plug and play" fluid-driven unit without any external power sources and equipment.