Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
Mais filtros

Bases de dados
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
BMC Plant Biol ; 24(1): 307, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38644483

RESUMO

BACKGROUND: Luffa (Luffa spp.) is an economically important crop of the Cucurbitaceae family, commonly known as sponge gourd or vegetable gourd. It is an annual cross-pollinated crop primarily found in the subtropical and tropical regions of Asia, Australia, Africa, and the Americas. Luffa serves not only as a vegetable but also exhibits medicinal properties, including anti-inflammatory, antidiabetic, and anticancer effects. Moreover, the fiber derived from luffa finds extensive applications in various fields such as biotechnology and construction. However, luffa Fusarium wilt poses a severe threat to its production, and existing control methods have proven ineffective in terms of cost-effectiveness and environmental considerations. Therefore, there is an urgent need to develop luffa varieties resistant to Fusarium wilt. Single-plant GWAS (sp-GWAS) has been demonstrated as a promising tool for the rapid and efficient identification of quantitative trait loci (QTLs) associated with target traits, as well as closely linked molecular markers. RESULTS: In this study, a collection of 97 individuals from 73 luffa accessions including two major luffa species underwent single-plant GWAS to investigate luffa Fusarium wilt resistance. Utilizing the double digest restriction site associated DNA (ddRAD) method, a total of 8,919 high-quality single nucleotide polymorphisms (SNPs) were identified. The analysis revealed the potential for Fusarium wilt resistance in accessions from both luffa species. There are 6 QTLs identified from 3 traits, including the area under the disease progress curve (AUDPC), a putative disease-resistant QTL, was identified on the second chromosome of luffa. Within the region of linkage disequilibrium, a candidate gene homologous to LOC111009722, which encodes peroxidase 40 and is associated with disease resistance in Cucumis melo, was identified. Furthermore, to validate the applicability of the marker associated with resistance from sp-GWAS, an additional set of 21 individual luffa plants were tested, exhibiting 93.75% accuracy in detecting susceptible of luffa species L. aegyptiaca Mill. CONCLUSION: In summary, these findings give a hint of genome position that may contribute to luffa wild resistance to Fusarium and can be utilized in the future luffa wilt resistant breeding programs aimed at developing wilt-resistant varieties by using the susceptible-linked SNP marker.


Assuntos
Resistência à Doença , Fusarium , Estudo de Associação Genômica Ampla , Luffa , Doenças das Plantas , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Fusarium/fisiologia , Polimorfismo de Nucleotídeo Único/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Resistência à Doença/genética , Luffa/genética , Luffa/microbiologia , Genoma de Planta , Marcadores Genéticos , Variação Genética
2.
Antimicrob Agents Chemother ; 66(2): e0166421, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34807763

RESUMO

Spontaneous severe acute exacerbation (SAE) is not uncommon in the natural history of chronic hepatitis B (CHB). Lamivudine (LAM) has the advantages of low price, quick onset, good efficacy, and no drug resistance within 24 weeks. This study aimed to compare the short-term efficacy of tenofovir disoproxil fumarate (TDF) and LAM for 24 weeks followed by TDF in the treatment of CHB with severe acute exacerbation. Consecutive patients of CHB with SAE were randomized to receive either TDF (19 patients) or LAM for 24 weeks, followed by TDF (18 patients). The primary endpoint was overall mortality or receipt of liver transplantation by week 24. This study was approved by the Institutional Review Board (IRB) of the Kaohsiung Veterans General Hospital (VGHKS12-CT5-10). The baseline characteristics were comparable between the two groups. By week 24, seven (37%) and five (28%) patients in the TDF and LAM-TDF groups died or received liver transplantation (P = 0.487). Multivariate analysis showed that albumin level, prothrombin time (PT), and hepatic encephalopathy were independent factors associated with mortality or liver transplantation by week 24. Early reductions in HBV DNA of more than or equal to 2 log at 1 and 2 weeks were similar between the two groups. The biochemical and virological responses at 12, 24, and 48 weeks were also similar between the two groups. TDF and LAM for 24 weeks followed by TDF achieved a similar clinical outcome in CHB patients with SAE. (This study has been registered at ClinicalTrials.gov under identifier NCT01848743).


Assuntos
Hepatite B Crônica , Hepatite B , Antivirais/farmacologia , DNA Viral , Farmacorresistência Viral , Quimioterapia Combinada , Hepatite B/tratamento farmacológico , Vírus da Hepatite B , Hepatite B Crônica/tratamento farmacológico , Humanos , Lamivudina/farmacologia , Lamivudina/uso terapêutico , Tenofovir/farmacologia , Tenofovir/uso terapêutico , Resultado do Tratamento
3.
J Nanobiotechnology ; 20(1): 435, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36195937

RESUMO

Exosomes of human cardiosphere-derived cells (CDCs) are very promising for treating cardiovascular disorders. However, the current challenge is inconvenient delivery methods of exosomes for clinical application. The present study aims to explore the potential to enhance the therapeutic effect of exosome (EXO) from human CDCs to myocardial hypertrophy. A heart homing peptide (HHP) was displayed on the surface of exosomes derived from CDCs that were forced to express the HHP fused on the N-terminus of the lysosomal-associated membrane protein 2b (LAMP2b). The cardiomyocyte-targeting capability of exosomes were analyzed and their therapeutic effects were evaluated in a mouse model of myocardial hypertrophy induced by transverse aorta constriction (TAC). The molecular mechanisms of the therapeutic effects were dissected in angiotensin II-induced neonatal rat cardiomyocyte (NRCMs) hypertrophy model using a combination of biochemistry, immunohistochemistry and molecular biology techniques. We found that HHP-exosomes (HHP-EXO) accumulated more in mouse hearts after intravenous delivery and in cultured NRCMs than control exosomes (CON-EXO). Cardiac function of TAC mice was significantly improved with intravenous HHP-EXO administration. Left ventricular hypertrophy was reduced more by HHP-EXO than CON-EXO via inhibition of ß-MHC, BNP, GP130, p-STAT3, p-ERK1/2, and p-AKT. Similar results were obtained in angiotensin II-induced hypertrophy of NRCMs, in which the beneficial effects of HHP-EXO were abolished by miRNA-148a inhibition. Our results indicate that HHP-EXO preferentially target the heart and improve the therapeutic effect of CDCs-exosomes on cardiac hypertrophy. The beneficial therapeutic effect is most likely attributed to miRNA-148a-mediated suppression of GP130, which in turn inhibits STAT3/ERK1/2/AKT signaling pathway, leading to improved cardiac function and remodeling.


Assuntos
Exossomos , MicroRNAs , Angiotensina II/metabolismo , Angiotensina II/farmacologia , Animais , Cardiomegalia/terapia , Receptor gp130 de Citocina/metabolismo , Exossomos/metabolismo , Humanos , Proteínas de Membrana Lisossomal/metabolismo , Camundongos , MicroRNAs/metabolismo , Miócitos Cardíacos/metabolismo , Peptídeos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos
4.
J Cell Mol Med ; 24(20): 12141-12153, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32918384

RESUMO

Doxorubicin cardiotoxicity is frequently reported in patients undergoing chemotherapy. The present study investigates whether cardiomyopathy induced by doxorubicin can be improved by the natural flavone acacetin in a mouse model and uncovers the potential molecular mechanism using cultured rat cardiomyoblasts. It was found that the cardiac dysfunction and myocardial fibrosis induced by doxorubicin were significantly improved by acacetin in mice with impaired Nrf2/HO-1 and Sirt1/pAMPK molecules, which is reversed by acacetin treatment. Doxorubicin decreased cell viability and increased ROS production in rat cardiomyoblasts; these effects are significantly countered by acacetin (0.3-3 µM) in a concentration-dependent manner via activating Sirt1/pAMPK signals and enhancing antioxidation (Nrf2/HO-1 and SOD1/SOD2) and anti-apoptosis. These protective effects were abolished in cells with silencing Sirt1. The results demonstrate for the first time that doxorubicin cardiotoxicity is antagonized by acacetin via Sirt1-mediated activation of AMPK/Nrf2 signal molecules, indicating that acacetin may be a drug candidate used clinically for protecting against doxorubicin cardiomyopathy.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Cardiomiopatias/induzido quimicamente , Cardiomiopatias/tratamento farmacológico , Doxorrubicina/efeitos adversos , Flavonas/uso terapêutico , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais , Sirtuína 1/metabolismo , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Cardiomiopatias/metabolismo , Cardiotônicos/farmacologia , Cardiotônicos/uso terapêutico , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Flavonas/farmacologia , Inativação Gênica , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/patologia , Masculino , Camundongos Endogâmicos C57BL , Miocárdio/patologia , Ratos , Espécies Reativas de Oxigênio/metabolismo
5.
BMC Infect Dis ; 18(1): 468, 2018 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-30223785

RESUMO

BACKGROUND: Most guidelines recommend 6 to 12 weeks of parenteral antibiotic treatment for pyogenic spondylodiscitis. When surgical debridement is adequately performed, further intravenous antibiotic treatment duration can be reduced than that of conservative treatment alone theoretically. However, the appropriate duration of post-surgical parenteral antibiotic treatment is still unknown. This study aimed to identify the risk factors of recurrence and evaluate the appropriate duration after surgical intervention. METHODS: This 3-year retrospective review included 102 consecutive patients who were diagnosed with pyogenic spondylodiscitis and underwent surgical intervention. Recurrence was defined as recurrent signs and symptoms and the need for another unplanned parenteral antibiotic treatment or operation within one year. This study included two major portions. First, independent risk factors for recurrence were identified by multivariable analysis, using the database of demographic information, pre-operative clinical signs and symptoms, underlying illness, radiographic findings, laboratory tests, intraoperative culture results, and treatment. Patients with any one of the risk factors were considered high-risk; those with no risk factors were considered low-risk. Recurrence rates after short-term (≤3 weeks) and long-term (> 3 weeks) parenteral antibiotic treatment were compared between the groups. RESULTS: Positive blood culture and paraspinal abscesses were identified as independent risk factors of recurrence. Accordingly, 59 (57.8%) patients were classified as low-risk and 43 (42.2%) as high-risk. Among the high-risk patients, a significantly higher recurrence rate occurred with short-term than with long-term antibiotic therapy (56.2% vs. 22.2%, p = 0.027). For the low-risk patients, there was no significant difference between short-term and long-term antibiotic therapy (16.0% vs. 20.6%, p = 0.461). CONCLUSIONS: The appropriate duration of parenteral antibiotic treatment in patients with pyogenic spondylodiscitis after surgical intervention could be guided by the risk factors. The duration of postoperative intravenous antibiotic therapy could be reduced to 3 weeks for patients without positive blood culture or abscess formation.


Assuntos
Abscesso/tratamento farmacológico , Abscesso/cirurgia , Antibacterianos/administração & dosagem , Discite/tratamento farmacológico , Discite/cirurgia , Abscesso/microbiologia , Administração Intravenosa , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Desbridamento , Discite/microbiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cuidados Pós-Operatórios/métodos , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
7.
Hepatology ; 62(2): 387-96, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26041578

RESUMO

UNLABELLED: Reactivation of hepatitis B viral (HBV) infection in cancer patients undergoing chemotherapy may cause interruption of chemotherapy and lead to liver failure and death. In our institute, a computerized order entry-based alert system was introduced in September 2011 to remind healthcare providers of HBV testing when prescribing chemotherapy. Since August 2012, an order entry-based therapeutic control system has been applied to ensure HBV prophylaxis during chemotherapy. This retrospective cohort study included cancer patients receiving chemotherapy in the Kaohsiung Veterans General Hospital from November 2009 to June 2013. The prechemotherapy HBV screening rate, HBV prophylactic rate, and severe HBV acute exacerbation rate were compared between stages with different order systems. Newly diagnosed cancer patients (n = 2512) were included. The HBV testing rate in the screening reminder stage was higher than that in the educational stage (93.5% versus 40.2%, P < 0.001), whereas the adequate HBV prophylactic rates in the two order entry-based stages were comparable (41.1% versus 39.2%). Patients in the order entry-based therapeutic control stage had a higher HBV screening rate (99.3% versus 40.2%, P < 0.001) and a higher HBV prophylactic rate (95.8% versus 39.2%, P < 0.001) than those in the educational stage. Additionally, the severe HBV acute exacerbation rate in the therapeutic control stage was lower than those in the educational and screening reminder stages (0% versus 1.2% and 1.2%, respectively; both P < 0.01). CONCLUSION: A computerized order entry-based therapeutic control system can provide excellent prechemotherapy HBV screening for cancer patients undergoing chemotherapy and can effectively prevent severe acute exacerbation of HBV infection in hospitals among HBV endemic areas.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Doenças Endêmicas , Vírus da Hepatite B/isolamento & purificação , Hepatite B Crônica/prevenção & controle , Neoplasias/tratamento farmacológico , Ativação Viral/efeitos dos fármacos , Doença Aguda , Adulto , Idoso , Análise de Variância , Anticorpos Monoclonais Murinos/administração & dosagem , Antivirais/uso terapêutico , Estudos de Coortes , Progressão da Doença , Feminino , Seguimentos , Hepatite B Crônica/tratamento farmacológico , Hepatite B Crônica/epidemiologia , Humanos , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Análise Multivariada , Neoplasias/patologia , Valor Preditivo dos Testes , Sistema de Registros , Estudos Retrospectivos , Medição de Risco , Rituximab , Resultado do Tratamento , Carga Viral/efeitos dos fármacos
8.
BMC Gastroenterol ; 16: 102, 2016 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-27565889

RESUMO

BACKGROUND: Sometimes, no definite filling defect could be found by cholangiogram (ERC) during the endoscopic retrograde cholangio-pancreatiographic (ERCP) exam; even prior images had evidence of common bile duct stones (CBDS). We aimed in estimating the positive rate of extraction of CBDS who had treated by endoscopic sphincterotomy/endoscopic papillary balloon dilation (EST/EPBD) with negative ERC finding. METHODS: One hundred forty-one patients with clinically suspicious of CBDS but negative ERC, who had received EST/EPBD treatments was enrolled. Potential factors for predicting CBDS, as well as the treatment-related complications were analyzed. RESULTS: Nearly half of the patients with negative ERC, had a positive stone extraction. Only patients with high probability of CBDS were significantly associated with positive stone extraction. Moreover, patients with intermediate probability of CBDS had higher rates of overall complications, including post-ERCP pancreatitis. In addition, no significant difference of post-ERCP pancreatitis was found between EST and EPBD groups in any one group of patients with the same probability of CBDS. CONCLUSIONS: Regarding patients with negative ERC, therapeutic ERCP is beneficial and safe for patients present with high probability of CBDS. Moreover, under the same probability of CBDS, there was no significance difference in post-ERCP pancreatitis between EST and EPBD.


Assuntos
Cateterismo/estatística & dados numéricos , Colangiopancreatografia Retrógrada Endoscópica/estatística & dados numéricos , Coledocolitíase/cirurgia , Dilatação/estatística & dados numéricos , Esfinterotomia Endoscópica/estatística & dados numéricos , Idoso , Cateterismo/efeitos adversos , Cateterismo/métodos , Colangiografia/métodos , Colangiografia/estatística & dados numéricos , Colangiopancreatografia Retrógrada Endoscópica/métodos , Coledocolitíase/diagnóstico por imagem , Dilatação/efeitos adversos , Dilatação/métodos , Reações Falso-Negativas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pancreatite/epidemiologia , Pancreatite/etiologia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Esfinterotomia Endoscópica/efeitos adversos , Esfinterotomia Endoscópica/métodos , Resultado do Tratamento
9.
Front Bioeng Biotechnol ; 12: 1359883, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38380264

RESUMO

Despite advancements in pedicle screw design and surgical techniques, the standard steps for inserting pedicle screws still need to follow a set of fixed procedures. The first step, known as establishing a pilot hole, also referred to as a pre-drilled hole, is crucial for ensuring screw insertion accuracy. In different surgical approaches, such as minimally invasive or traditional surgery, the method of creating pilot holes varies, resulting in different pilot hole profiles, including variations in size and shape. The aim of this study is to evaluate the biomechanical properties of different pilot hole profiles corresponding to various surgical approaches. Commercially available synthetic L4 vertebrae with a density of 0.16 g/cc were utilized as substitutes for human bone. Four different pilot hole profiles were created using a 3.0 mm cylindrical bone biopsy needle, 3.6 mm cylindrical drill, 3.2-5.0 mm conical drill, and 3.2-5.0 mm conical curette for simulating various minimally invasive and traditional spinal surgeries. Two frequently employed screw shapes, namely, cylindrical and conical, were selected. Following specimen preparation, screw pullout tests were performed using a material test machine, and statistical analysis was applied to compare the mean maximal pullout strength of each configuration. Conical and cylindrical screws in these four pilot hole configurations showed similar trends, with the mean maximal pullout strength ranking from high to low as follows: 3.0 mm cylindrical biopsy needle, 3.6 mm cylindrical drill bit, 3.2-5.0 mm conical curette, and 3.2-5.0 mm conical drill bit. Conical screws generally exhibited a greater mean maximal pullout strength than cylindrical screws in three of the four different pilot hole configurations. In the groups with conical pilot holes, created with a 3.2-5.0 mm drill bit and 3.2-5.0 mm curette, both conical screws exhibited a greater mean maximal pullout strength than did cylindrical screws. The strength of this study lies in its comprehensive comparison of the impact of various pilot hole profiles commonly used in clinical procedures on screw fixation stability, a topic rarely reported in the literature. Our results demonstrated that pilot holes created for minimally invasive surgery using image-guided techniques exhibit superior pullout strength compared to those utilized in traditional surgery. Therefore, we recommend prioritizing minimally invasive surgery when screw implantation is anticipated to be difficult or there is a specific need for stronger screw fixation. When opting for traditional surgery, image-guided methods may help establish smaller pilot holes and increase screw fixation strength.

10.
Spine J ; 2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38499068

RESUMO

BACKGROUND CONTEXT: Long-segment pedicle screw instrumentation is widely used to treat complex spinal disorders. Rods are routinely precontoured to maximize assistance on the correcting side of the deformity, but there often exists a residual gap discrepancy between the precontoured rods and screw tulips. No previous research has investigated the diminished pullout strength of the most proximal or distal pedicle screw resulting from a mismatched rod in long-segment pedicle screw instrumentation. PURPOSE: The present study aimed to investigate the decreased pullout force of pedicle screws affected by the gap discrepancy when forcefully engaging a mismatched rod into a tulip in a normal-density porcine spine. STUDY DESIGN: The pedicle screw fixation strength under axial pullout force was compared among three different gap discrepancies between rods and tulips using long porcine spine segments. METHODS: Twelve porcine lumbar vertebrae (L3-L6) were implanted with pedicle screws and rods. Screws on one side had no gap between the tulip and rod (0-mm group), while the most proximal screw on the other side had an intentional gap of 3 mm (3-mm group) or 6 mm (6-mm group). Three hours after forcefully engaging the rod into the tulips at room temperature, the set screws in all specimens were loosened, and each specimen was dissected into individual vertebrae for subsequent pullout testing. RESULTS: The control group exhibited significantly greater pullout strength (1987.68 ± 126.80 N) than the groups from different rod-tulip configurations (p<.05), with significantly greater strength in the 3-mm group (945.62 ± 97.43 N) than the 6-mm group (655.30 ± 194.49 N) (p<.05). Only 47.6% and 33.0% of the pullout strength was retained in the 3-mm and 6-mm groups, respectively, compared to the control group. CONCLUSIONS: Gap discrepancies between rods and tulips can significantly reduce pedicle screw pullout strength, with a correlation between decreased strength and increased gaps. Surgeons should avoid forcefully engaging mismatched rods and consider well-fitted contoured rods in spinal surgery to minimize the risk of screw loosening. CLINICAL SIGNIFICANCE: The gap discrepancy between rod and tulip significantly affected pullout strength, with greater gaps leading to reduced strength. Forcefully engaging mismatched rods into tulips in degenerative spinal surgery should be avoided to minimize the risk of early screw pullout.

11.
Spine J ; 23(2): 315-324, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36058516

RESUMO

BACKGROUND CONTEXT: Pedicle screw-rod assembly procedures following pedicle screw insertion include contouring and placing rods into screw tulips, introducing set screws into the tulip along the screw thread, applying a counter-torque holder and tightening all the set screws clockwise. Even if an appropriate pedicle screw is implanted, screw dislodgement after tightening of the tulip and set screw is not uncommon. Pedicle wall violation resulting from excessive rotational force due to inadequate use of a counter-torque holder might be the reason. However, the strain change in the pedicle during tulip-set screw tightening and the role of counter-torque have never been investigated. PURPOSE: This study determined differences in the strain change in the outer and inner pedicle walls during tulip-set screw tightening; additionally, the influence of counter-torque on pedicle wall violation was elucidated. STUDY DESIGN: A controlled biomechanical study; the strain values of outer and inner pedicle walls in cadaveric porcine L4-L5 vertebrae during tulip-set screw tightening with or without a counter-torque holder were measured. METHODS: Twelve L4-L5 fresh-frozen porcine lumbar vertebrae were implanted with screw-rod constructs; the set screw was randomly locked into the tulip in the right L5, right L4, left L5 and left L4 testing groups. The maximal values from eight strain gauges (P-R-O: outer cortex of right pedicle in proximal vertebra; P-R-I: inner cortex of right pedicle in proximal vertebra; D-R-O: outer cortex of right pedicle in distal vertebra; D-R-I: inner cortex of right pedicle in distal vertebra; P-L-O: outer cortex of left pedicle in proximal vertebra; P-L-I: inner cortex of left pedicle in proximal vertebra; D-L-O: outer cortex of left pedicle in distal vertebra; D-L-I: outer cortex of left pedicle in proximal vertebra) for each specimen during tightening to 12 Nm were measured. RESULTS: The maximal strain values of the ipsilateral strain gauges in all testing groups were almost significantly higher when a counter-torque holder was not used than when one was used. The strain values in the adjacent pedicle of specimens without a counter-torque holder were significantly increased: P-R-O and P-R-I in the right L5 group; D-R-I in the right L4 group; P-L-I and P-L-O in the left L5 group; D-L-O and D-L-I in the left L4 group. CONCLUSIONS: The constraint effect of counter-torque during tulip-set screw tightening is necessary. Clockwise rotational force with a fragile lateral pedicle wall suggests that caution is required when using a counter-torque holder to tighten the right L5 and left L4 constructs. CLINICAL SIGNIFICANCE: A counter-torque holder is important during tulip-set screw tightening; improper use may lead to adjacent pedicle wall violation, sequentially resulting in pedicle screw loosening.


Assuntos
Parafusos Pediculares , Fusão Vertebral , Animais , Fenômenos Biomecânicos , Vértebras Lombares/cirurgia , Fusão Vertebral/métodos , Suínos , Torque
12.
Sci Rep ; 13(1): 454, 2023 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-36624133

RESUMO

Although an anterior approach with anterior lateral screw fixation has been developed for stabilizing the thoracolumbar spine clinically, screw loosening still occurs. In this novel in vitro study, we attempted to elucidate the optimal screw position in the lateral lumbar vertebra and the effect of bicortical fixation. A total of 72 fresh-frozen lumbar vertebrae from L1-6 were harvested from 12 mature pigs and randomly assigned to two modalities: bicortical fixation (n = 36) and unicortical fixation (n = 36). Six groups of screw positions in the lateral vertebral body in each modality were designated as central-anterior, central-middle, central-posterior, lower-anterior, lower-middle, and lower- posterior; 6 specimens were used in each group. The correlations between screw fixation modalities, screw positions and axial pullout strength were analyzed. An appropriate screw trajectory and insertional depth were confirmed using axial and sagittal X-ray imaging prior to pullout testing. In both bicortical and unicortical fixation modalities, the screw pullout force was significantly higher in the posterior or middle position than in the anterior position (p < 0.05), and there was no significant differences between the central and lower positions. The maximal pullout forces from the same screw positions in unicortical fixation modalities were all significantly lower, decreases that ranged from 32.7 to 74%, than those in bicortical fixation modalities. Our study using porcine vertebrae showed that screws in the middle or posterior position of the lateral vertebral body had a higher pullout performance than those in the anterior position. Posteriorly positioned lateral vertebral screws with unicortical fixation provided better stability than anteriorly positioned screws with bicortical fixation.


Assuntos
Parafusos Ósseos , Fusão Vertebral , Suínos , Animais , Cadáver , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Radiografia , Fenômenos Biomecânicos
13.
Front Bioeng Biotechnol ; 11: 1182265, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37324423

RESUMO

Ball-and-socket designs of cervical total disc replacement (TDR) have been popular in recent years despite the disadvantages of polyethylene wear, heterotrophic ossification, increased facet contact force, and implant subsidence. In this study, a non-articulating, additively manufactured hybrid TDR with an ultra-high molecular weight polyethylene core and polycarbonate urethane (PCU) fiber jacket, was designed to mimic the motion of normal discs. A finite element (FE) study was conducted to optimize the lattice structure and assess the biomechanical performance of this new generation TDR with an intact disc and a commercial ball-and-socket Baguera®C TDR (Spineart SA, Geneva, Switzerland) on an intact C5-6 cervical spinal model. The lattice structure of the PCU fiber was constructed using the Tesseract or the Cross structures from the IntraLattice model in the Rhino software (McNeel North America, Seattle, WA) to create the hybrid I and hybrid II groups, respectively. The circumferential area of the PCU fiber was divided into three regions (anterior, lateral and posterior), and the cellular structures were adjusted. Optimal cellular distributions and structures were A2L5P2 in the hybrid I and A2L7P3 in the hybrid II groups. All but one of the maximum von Mises stresses were within the yield strength of the PCU material. The range of motions, facet joint stress, C6 vertebral superior endplate stress and path of instantaneous center of rotation of the hybrid I and II groups were closer to those of the intact group than those of the Baguera®C group under 100 N follower load and pure moment of 1.5 Nm in four different planar motions. Restoration of normal cervical spinal kinematics and prevention of implant subsidence could be observed from the FE analysis results. Superior stress distribution in the PCU fiber and core in the hybrid II group revealed that the Cross lattice structure of a PCU fiber jacket could be a choice for a next-generation TDR. This promising outcome suggests the feasibility of implanting an additively manufactured multi-material artificial disc that allows for better physiological motion than the current ball-and-socket design.

14.
Front Bioeng Biotechnol ; 11: 1151627, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37214307

RESUMO

Intraoperative pedicle screw depth adjustment after initial insertion, including both forward and backward adjustments, is sometimes necessary to facilitate rod application and ensure that the screw is in the correct position, which is determined by intraoperative fluoroscopy. Adjusting the screw with forward turns has no negative influence on the screw fixation stability; however, screw turnback may weaken the fixation stability. The aim of this study is to evaluate the biomechanical properties of screw turnback and demonstrate the reduction in the fixation stability after the screw is turned 360° from its full insertion position. Commercially available synthetic closed-cell polyurethane foams with three different densities simulating various degrees of bone density were utilized as substitutes for human bone. Two different screw shapes (cylindrical and conical) together with two different pilot hole profiles (cylindrical and conical) were tested. Following specimen preparation, screw pullout tests were conducted using a material test machine. The mean maximal pullout strength between full insertion and 360-degree turnback from full insertion in each setting was statistically analyzed. The mean maximal pullout strength after 360-degree turnback from full insertion was generally lower than that at full insertion. The reduced mean maximal pullout strength after turnback increased with decreasing bone density. Conical screws had significantly lower pullout strength after 360-degree turnback than cylindrical screws. The mean maximal pullout strength was reduced by up to approximately 27% after 360-degree turnback when using a conical screw in a low bone density specimen. Additionally, specimens treated with a conical pilot hole presented a less reduction in pullout strength after screw turnback as compared to those with a cylindrical pilot hole. The strength of our study was that we systematically investigated the effects of various bone densities and screw shapes on screw stability after turnback, which has rarely been reported in the literature. Our study suggests that pedicle screw turnback after full insertion should be reduced in spinal surgeries, particularly procedures that use conical screws in osteoporotic bone. Pedicle screw secured with a conical pilot hole might be beneficial for screw adjustment.

15.
Biochem Pharmacol ; 209: 115443, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36720353

RESUMO

Several clinical trials observed that enzastaurin prolonged QT interval in cancer patients. However, the mechanism of enzastaurin-induced QT interval prolongation is unclear. Therefore, this study aimed to assess the effect and mechanism of enzastaurin on QT interval and cardiac function. The Langendorff and Ion-Optix MyoCam systems were used to assess the effects of enzastaurin on QT interval, cardiac systolic function and intracellular Ca2+ transient in guinea pig hearts and ventricular myocytes. The effects of enzastaurin on the rapid delayed rectifier (IKr), the slow delayed rectifier K+ current (IKs), transient outward potassium current (Ito), action potentials, Ryanodine Receptor 2 (RyR2) and the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a) expression and activity in HEK 293 cell system and primary cardiomyocytes were investigated using whole-cell recording technique and western blotting. We found that enzastaurin significantly prolonged QT interval in guinea pig hearts and increased the action potential duration (APD) in guinea pig cardiomyocytes in a dose-dependent manner. Enzastaurin potently inhibited IKr by binding to the human Ether-à-go-go-Related gene (hERG) channel in both open and closed states, and hERG mutant channels, including S636A, S631A, and F656V attenuated the inhibitory effect of enzastaurin. Enzastaurin also moderately decreased IKs. Additionally, enzastaurin also induced negative chronotropic action. Moreover, enzastaurin impaired cardiac systolic function and reduced intracellular Ca2+ transient via inhibition of RyR2 phosphorylation. Taken together, we found that enzastaurin prolongs QT, reduces heart rate and impairs cardiac systolic function. Therefore, we recommend that electrocardiogram (ECG) and cardiac function should be continuously monitored when enzastaurin is administered to cancer patients.


Assuntos
Síndrome do QT Longo , Canal de Liberação de Cálcio do Receptor de Rianodina , Humanos , Animais , Cobaias , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Células HEK293 , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/metabolismo , Miócitos Cardíacos , Potenciais de Ação , Canais de Potássio Éter-A-Go-Go
16.
Opt Lett ; 37(15): 3228-30, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22859141

RESUMO

A terahertz (THz) in-line digital holography project has been proposed based on a CO2 pumped 2.52 THz continuous-wave laser and a pyroelectric-array camera used as the detector. The THz Gabor in-line digital holograms have been obtained and then the high resolution reconstruction of THz in-line digital holography was realized. The resolution of an in-line digital holography system has been tested by the use of a series of objects. High-quality and high-resolution reconstructed images have been obtained, and the real lateral resolution is higher than 0.2 mm. It can be inferred from the results that the THz Gabor in-line digital holography system has the abilities of real-time and high-resolution imaging.

17.
J Nanosci Nanotechnol ; 12(2): 1296-300, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22629942

RESUMO

The last decade has seen great in electrochromic (EC) technology for smart windows and displays. In this study, WTiOx films formed from TiO2 and WO3 were deposited onto ITO glass with a sheet resistance of 10 Omega cm and on silicon substrates, by pulsed magnetron sputtering using a W and Ti alloy target. The films were deposited at plasma powers 100, 200, 300, 400 and 500 W using a gaseous Ar (150 sccm)/O2 (50 sccm) mixture; the working pressure was fixed at 5E-2 torr. The film thickness increased with the plasma power. However, increasing the plasma power yielded a more crystalline structure with poorer electrochromic properties. The influence of Ti doping and plasma power on the structural, optical and electrochromic properties of the WTiOx thin films was studied. WTiOx films grown at various plasma powers of under 400 W were amorphous. Deposition of films at 400 W yielded the optimal electrochromic properties, with high optical modulation, high coloration efficiency and the lowest color memory effect at wavelengths 400, 550 and 800 nm. An XPS study indicated that Ti can stabilize the valence state of W6+. The improvements caused by the doping with Ti were tested: an optical density (OD) of close to 0.85 and a maximum delta T (%) at 400 nm of 25.8%, at 550 nm of 52.5% and at 800 nm (in the near-IR region) of 62.4%.

18.
Appl Opt ; 51(29): 7052-8, 2012 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-23052085

RESUMO

Terahertz (THz) radiation has the characteristics of penetrating nonmetallic and nonpolar materials that are opaque to visible light, which makes THz digital holography have an application potential of imaging concealed objects with certain barriers. A CO(2) pumped continuous THz Gabor inline digital holographic imaging system was utilized to conduct experimental researches on imaging concealed objects. Paper, Teflon, a plastic express envelope, and silicon wafers were used as barriers. High-quality reconstructed images were obtained. Compared with the reconstruction results without any barriers, the results verify the feasibility of THz Gabor inline digital holography in imaging concealed objects.

19.
Sci Rep ; 12(1): 2739, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35177724

RESUMO

Polymethylmethacrylate (PMMA) has been applied clinically and biomechanically repair loose pedicle screws. Controversies have arisen over data due to uncontrolled cement properties, various locations and sizes of fenestrated holes in repair screws, irregular holes and different bone densities of specimens. In this study, the pullout strength was compared for two techniques, the modified technique to use PMMA to augment a threaded hole and the traditional technique with retrograde injection of a PMMA filling, for standard loose screws in porcine vertebrae. Both techniques provided statistically significant results for sufficiently randomized specimens and experimental procedures. The difference in the pullout strength between conical and cylindrical screws for the aforementioned cement augmentation techniques was also investigated. Twenty-four single-level fresh-frozen lumbar vertebrae from L1 to L6 were harvested from four mature pigs. A total of 0.8 ml of PMMA was retrograde injected into screw holes with a 5.5 mm diameter, followed by insertion of a 5.0 mm diameter repair screw in the traditional group (n = 12). A stiff threaded PMMA hole was created with a 4.5 mm tapping screw before insertion of repair screws in the modified group (n = 12). Two screw geometries were randomly assigned as cylindrical (n = 6) and conical (n = 6) in each group. The correlations between filling techniques, screw geometries and axial pullout strength were analyzed. An appropriate screw trajectory and insertion depth were confirmed using X-ray imaging prior to pullout testing in both groups. For a given screw geometry (cylindrical or conical), the pullout force of the modified group was significantly higher than that of the traditional group. There was no significant difference in the pullout force between the screw geometries for a given filling technique. The cement augmentation technique is far more influential than the screw outer geometry. The modified PMMA technique created a greater anchor force than the traditional method and could be an alternative for revision of pedicle screw loosening.


Assuntos
Cimentos Ósseos/farmacologia , Vértebras Lombares/cirurgia , Parafusos Pediculares , Animais , Suínos
20.
Saudi J Gastroenterol ; 28(2): 108-114, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35295067

RESUMO

Background: The impact of propranolol on patients with cirrhosis and refractory ascites is controversial. We conducted a nationwide longitudinal cohort study to compare the survival between patients with cirrhosis and refractory ascites, with and without using propranolol. Methods: Data of patients with cirrhosis and refractory ascites using propranolol, and controls matched by age and gender, were extracted from The National Health Insurance Research Database of Taiwan. The baseline demographic characteristics were compared between groups. Cox regression analysis was used to examine the predictors of mortality. Results: In this study, 1788 patients were enrolled in each group; 1304 patients (72.9%) in the propranolol group and 1445 patients (80.8%) in the control group died (P < 0.001). The mean survival was 34.3 ± 31.2 months in the propranolol group and 20.8 ± 26.6 months in the control group (P < 0.001). Propranolol (hazard ratio [HR]: 0.60, 95% confidence interval [CI]: 0.55-0.64, P < 0.001), statins (HR: 0.43, 95% CI: 0.34-0.56, P < 0.001), age (HR: 1.02, 95% CI: 1.01-1.02, P < 0.001), and diabetes mellitus (HR: 1.14, 95% CI: 1.05-1.24, P = 0.002) were the independent predictors for mortality. Conclusions: Use of propanolol was associated with reduced mortality, compared with controls, in this nationwide cohort of patients with cirrhosis and refractory ascites.


Assuntos
Ascite , Propranolol , Ascite/tratamento farmacológico , Ascite/epidemiologia , Humanos , Cirrose Hepática/complicações , Cirrose Hepática/tratamento farmacológico , Estudos Longitudinais , Modelos de Riscos Proporcionais , Propranolol/uso terapêutico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA