explant

Explant
  • 文章类型: Journal Article
    The liver imaging reporting data system (LI-RADS) for hepatocellular carcinoma (HCC) was proposed to standardize and enhance consensus of reporting. However, clinical utility of LI-RADS has not been evaluated in Latin America. We therefore sought to compare LI-RADS categories with histopathology findings in liver transplant (LT) explants in a regional center.
    Prospective cohort study conducted between 2012 and 2018 in a single center from Argentina including patients with HCC listed for LT. LI-RADS definitions were applied to magnetic resonance images (MRI) or computed tomography (CT) abdominal scans at time of listing and at final pre-LT reassessment and compared to explant pathology findings; specifically, major nodule (NOD1).
    Of 130 patients with HCC listed for LT (96.1% with cirrhosis and 35.6% with hepatitis C virus infection), 72 underwent LT. Overall, 65% had imaging HCC diagnosis based on MRI (n = 84), 26% with CT (n = 34) and 9% (n = 12) with both methods. Among LT patients with pre-transplant imaging at our institution (n = 42/72), 69% of the NOD1 were LR-5, 21% LR-4 and 10% LR-3. Definite HCC diagnosis was 50% in LR-3 NOD1 (CI 18-90); none presented microvascular invasion. In LR-4 NOD1, HCC was confirmed in 89% (CI 59-98), of which 11% showed microvascular invasion; whereas in LR-5 NOD1 77% (CI 64-87) had confirmed HCC, 17% with microvascular invasion.
    LI-RADS was useful to standardize reports; however, no significant differences were observed between LR-4 and LR-5 HCC probability when compared to explant pathology.
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  • 文章类型: Journal Article
    BACKGROUND: Although keloids have been empirically treated with steroids and radiation, evidence-based radiation parameters for keloid therapy are lacking.
    OBJECTIVE: To determine evidence-based radiation parameters for blocking keloid fibroblast proliferation in vitro and apply them to patients.
    METHODS: The effects of various radiation parameters and steroids on cell proliferation, cell death, and collagen production in keloid explants and fibroblasts were evaluated with standard assays. Effective radiation parameters were then tested on patients.
    RESULTS: No differences were observed between the effects of 50 and 320 kV radiation or between single and fractionated radiation doses on keloid fibroblasts. A 3 Gy, 50 kV dose inhibited keloid fibroblast proliferation in culture, whereas 9 Gy completely blocked their outgrowth from explants by inducing multiple cell death pathways and reducing collagen levels. Thirteen of 14 keloids treated with a single 8 Gy, 50 kV dose of radiation did not recur, although 4 patients with 6 keloids were lost to follow-up.
    CONCLUSIONS: Seventy-five percent of patients received steroids for pruritus, whereas approximately 25% of patients were lost to follow-up.
    CONCLUSIONS: A single 8 Gy dose of superficial 50 kV radiation delivered an average of 34 days after keloid excision maybe sufficient to minimize recurrence, including in individuals resistant to steroids. Higher radiation energies, doses, or fractions may be unnecessary for keloid therapy.
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  • 文章类型: Journal Article
    怀孕期间寨卡病毒(ZIKV)感染可导致先天性寨卡综合症,其特征是小头畸形和其他神经发育障碍。在这一章中,我们描述了在人胎脑星形胶质细胞和组织外植体中体外ZIKV感染的建模方法。这些基于细胞和组织的平台可用于阐明ZIKV持久性的机制,并可能导致有关病毒诱导的神经发病机理的重要线索。此外,这些离体模型系统使研究人员能够在发育中的人脑更具代表性的环境中进行药物发现和开发实验。
    Zika virus (ZIKV) infection during pregnancy can result in congenital Zika syndrome which is characterized by microcephaly and other neurodevelopmental disorders. In this chapter, we describe methods to model ex vivo ZIKV infection in astrocytes and tissue explants from human fetal brain. These cell- and tissue-based platforms have been useful to elucidate mechanisms of ZIKV persistence and might lead to important clues about virus-induced neuropathogenesis. In addition, these ex vivo model systems allow researchers to conduct drug discovery and development experiments in more representative settings of the developing human brain.
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  • 文章类型: Journal Article
    Colchicine (COL) shows strong anticancer activity but due to its toxicity towards normal cells its wider application is limited. To address this issue, a library of 17 novel COL derivatives, namely N-carbamates of N-deacetyl-4-(bromo/chloro/iodo)thiocolchicine, has been tested against two types of primary cancer cells. These included acute lymphoblastic leukemia (ALL) and human breast cancer (BC) derived from two different tumor subtypes, ER+ invasive ductal carcinoma grade III (IDCG3) and metastatic carcinoma (MC). Four novel COL derivatives showed higher anti-proliferative activity than COL (IC50  = 8.6 nM) towards primary ALL cells in cell viability assays (IC50 range of 1.1-6.4 nM), and several were more potent towards primary IDCG3 (IC50 range of 0.1 to 10.3 nM) or MC (IC50 range of 2.3-9.1 nM) compared to COL (IC50 of 11.1 and 11.7 nM, respectively). In addition, several derivatives were selectively active toward primary breast cancer cells compared to normal breast epithelial cells. The most promising derivatives were subsequently tested against the NCI panel of 60 human cancer cell lines and seven derivatives were more potent than COL against leukemia, non-small-cell lung, colon, CNS and prostate cancers. Finally, COL and two of the most active derivatives were shown to be effective in killing BC cells when tested ex vivo using fresh human breast tumor explants. The present findings indicate that the select COL derivatives constitute promising lead compounds targeting specific types of cancer.
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  • 文章类型: Journal Article
    UNASSIGNED: Cellular therapy clinical applications require large-scale production of stem cells. Therefore, abundance, ease of isolation, and proliferative potential are the most important factors in choosing the appropriate source of cells for transplantation studies. Multipotent stem cells obtained from periodontal ligament (PDL) can be used in periodontal tissue regeneration. In this study, we aimed to evaluate and compare the characteristics of periodontal ligament stem cells (PDLSCs), extracted by either enzymatic digestion or explant methods, and expanded using two different serum types: fetal bovine serum (FBS) and xeno-free platelet lysate (PL).
    UNASSIGNED: Expanded PDLSCs were assessed for their proliferation capacity, surface markers expression, colony formation, differentiation potential and ability to self-renewal. Most importantly, PDLSCs were evaluated for their ability to produce osteoblasts in vitro.
    UNASSIGNED: PDLSCs isolated by explant method and expanded in PL serve as a promising source of stem cells for osteoblasts regeneration. These cells showed higher proliferation capacity, they retained their stemness characteristics throughout the passages and they revealed an increase in the expression level of osteogenic markers, without showing any karyotypic abnormalities after cell expansion.
    UNASSIGNED: PDLSCs produced using explant extraction method and expanded in cell culture media supplemented with PL provide an excellent source of xeno-free cells for the generation of functional osteoblasts.
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  • 文章类型: Journal Article
    Epithelial cells represent one of the most important physical barriers to many bacterial pathogens. In the case of Neisseria gonorrhoeae, the epithelial cell response is critical because they are the main target of the tissue damage triggered by the pathogen, particularly when the organism reaches the Fallopian tube (FT). Although the irreversible damage triggered by N. gonorrhoeae in the FT has been previously reported (ectopic pregnancy, pelvic inflammatory disease and infertility), the mechanisms of gonococcal-induced tissue damage are not fully understood. In addition, the lack of animal models that efficiently mimic the human disease and the complexity of gonococcus-host interactions make studying gonococcal pathogenesis particularly difficult. The use of human immortalized cells is also limited, since a variety of commercial FT cell lines is not yet available. Finally, the phase and antigenic variation of many gonococcal surface molecules involved in attachment and invasion of epithelial tissues leads to a failure to reproduce results using different human cells lines used in previous studies. The FT organ in culture (FTOC) and primary human fallopian tube epithelial cell (FTEC) represent the closest ex vivo cell models to explore the biology of Neisseria gonorrhoeae during infection of the FT, since it is a natural host target of the gonococcus. In this chapter, we describe protocols to process human FT samples to obtain FTOC and FTEC and assess their response to infection with Neisseria gonorrhoeae.
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  • 文章类型: Journal Article
    Sacral neuromodulation is an effective therapy for overactive bladder, urinary retention, and fecal incontinence. Infection after sacral neurostimulation is costly and burdensome. Determining optimal perioperative management strategies to reduce the risk of infection is important to reduce this burden.
    We sought to identify risk factors associated with sacral neurostimulator infection requiring explantation, to estimate the incidence of infection requiring explantation, and identify associated microbial pathogens.
    This is a multicenter retrospective case-control study of sacral neuromodulation procedures completed from Jan. 1, 2004, through Dec. 31, 2014. We identified all sacral neuromodulation implantable pulse generator implants as well as explants due to infection at 8 participating institutions. Cases were patients who required implantable pulse generator explantation for infection during the review period. Cases were included if age ≥18 years old, follow-up data were available ≥30 days after implantable pulse generator implant, and the implant was performed at the institution performing the explant. Two controls were matched to each case. These controls were the patients who had an implantable pulse generator implanted by the same surgeon immediately preceding and immediately following the identified case who met inclusion criteria. Controls were included if age ≥18 years old, no infection after implantable pulse generator implant, follow-up data were available ≥180 days after implant, and no explant for any reason <180 days from implant. Controls may have had an explant for reasons other than infection at >180 days after implant. Fisher exact test (for categorical variables) and Student t test (for continuous variables) were used to test the strength of the association between infection and patient and surgery characteristics. Significant variables were then considered in a multivariable logistic regression model to determine risk factors independently associated with infection.
    Over a 10-year period at 8 academic institutions, 1930 sacral neuromodulator implants were performed by 17 surgeons. In all, 38 cases requiring device explant for infection and 72 corresponding controls were identified. The incidence of infection requiring explant was 1.97%. Hematoma formation (13% cases, 0% controls; P = .004) and pocket depth of ≥3 cm (21% cases, 0% controls; P = .031) were independently associated with an increased risk of infection requiring explant. On multivariable regression analysis controlling for significant variables, both hematoma formation (P = .006) and pocket depth ≥3 cm (P = .020, odds ratio 3.26; 95% confidence interval, 1.20-8.89) remained significantly associated with infection requiring explant. Of the 38 cases requiring explant, 32 had cultures collected and 24 had positive cultures. All 5 cases with a hematoma had a positive culture (100%). Of the 4 cases with a pocket depth ≥3 cm, 2 had positive cultures, 1 had negative cultures, and 1 had a missing culture result. The most common organism identified was methicillin-resistant Staphylococcus aureus (38%).
    Infection after sacral neuromodulation requiring device explant is low. The most common infectious pathogen identified was methicillin-resistant S aureus. Demographic and health characteristics did not predict risk of explant due to infection, however, having a postoperative hematoma or a deep pocket ≥3 cm significantly increased the risk of explant due to infection. These findings highlight the importance of meticulous hemostasis as well as ensuring the pocket depth is <3 cm at the time of device implant.
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  • 文章类型: Comparative Study
    目的:我们试图确定在大直径(LD)金属对金属(MoM)髋关节置换术系统中使用时,钴铬合金(CoCr)股骨柄锥形(耳轴)是否比钛(Ti)合金柄锥形(耳轴)磨损更多。
    方法:我们使用经过验证的方法进行了外植体分析,以确定与钛合金(n=28)或CoCr股骨茎(n=21)一起使用的外植体LDCoCrMoM髋关节置换术的锥形表面的体积材料损失。仅包括具有粗糙的阳锥形表面和接近5.666°的标称夹角的12/14锥形构造。使用锥角进行多元回归建模,锥度粗糙度,轴承直径(水平杠杆臂)作为独立变量。使用坐标测量机绘制了材料损失图,轮廓术和扫描电子显微镜。
    结果:在对其他因素进行调整后,发现CoCr茎锥度比等效的Ti茎锥度具有明显更大的体积材料损失。
    结论:当在LDMoM髋关节翻修期间发现锥形连接损伤时,应该怀疑由标准CoCr合金组成的阳锥度对锥锥几何形状有持续的显著变化,这可能比影响钛合金杆的变化更广泛。引用这篇文章:骨关节J2017;99-B:1304-12。
    OBJECTIVE: We sought to determine whether cobalt-chromium alloy (CoCr) femoral stem tapers (trunnions) wear more than titanium (Ti) alloy stem tapers (trunnions) when used in a large diameter (LD) metal-on-metal (MoM) hip arthroplasty system.
    METHODS: We performed explant analysis using validated methodology to determine the volumetric material loss at the taper surfaces of explanted LD CoCr MoM hip arthroplasties used with either a Ti alloy (n = 28) or CoCr femoral stem (n = 21). Only 12/14 taper constructs with a rough male taper surface and a nominal included angle close to 5.666° were included. Multiple regression modelling was undertaken using taper angle, taper roughness, bearing diameter (horizontal lever arm) as independent variables. Material loss was mapped using a coordinate measuring machine, profilometry and scanning electron microscopy.
    RESULTS: After adjustment for other factors, CoCr stem tapers were found to have significantly greater volumetric material loss than the equivalent Ti stem tapers.
    CONCLUSIONS: When taper junction damage is identified during revision of a LD MoM hip, it should be suspected that a male taper composed of a standard CoCr alloy has sustained significant changes to the taper cone geometry which are likely to be more extensive than those affecting a Ti alloy stem. Cite this article: Bone Joint J 2017;99-B:1304-12.
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  • 文章类型: Journal Article
    BACKGROUND: Spinal cord stimulation (SCS) devices are cost effective and improve function as well as quality of life. Despite the demonstrated benefits of SCS, some patients have the device explanted. We are interested in exploring the patient characteristics of those explanted.
    METHODS: This is a retrospective chart review of neurostimulation patients who underwent explantation at 18 centers across the United States within the previous five years.
    RESULTS: Data from 352 patients were collected and compiled. Failed Back Surgery syndrome was the most common diagnosis (38.9%; n = 136/350) and over half of the patients reported numerical rating scale (NRS) scores ≥8 prior to implant (64.3%; n = 207/322). All patients reported changes in NRS scores across time, with an initial decrease after implant followed by a pre-explant increase (F (2, 961) = 121.7, p < 0.001). The most common reason for device explant was lack or loss of efficacy (43.9%; 152/346) followed by complications (20.2%; 70/346). Eighteen percent (18%; 62/343) of patients were explanted by a different physician than the implanting one. Rechargeable devices were explanted at a median of 15 months, whereas primary cell device explants occurred at a median of 36 months (CI 01.434, 2.373; median endpoint time ratio = 2.40).
    CONCLUSIONS: Loss or lack of efficacy and complications with therapy represent the most frequent reasons for neurostimulation explantation. Of the devices that were explanted, therapy was terminated earlier when devices were rechargeable, when complications occurred, or when pain relief was not achieved or maintained. Furthermore, in nearly 20% of the cases, a different provider than the implanting physician performed device removal.
    CONCLUSIONS: SCS is largely a safe and efficacious strategy for treating select chronic refractory pain syndromes. Further prospective data and innovation are needed to improve patient selection, maintain SCS therapeutic efficacy and reduce the reasons that lead to device explant.
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  • 文章类型: Journal Article
    Two-photon intravital microscopy (2P-IVM) is an advanced imaging platform that allows the visualization of dynamic processes at subcellular resolution in vivo. Dynamic processes like cell migration, cell proliferation, cell-cell interactions, and cell signaling have an interactive character and occur in complex environments. Hence, it is of pivotal importance to study these processes in living animals, using for example 2P-IVM. 2P-IVM can be performed on a variety of tissues, from the skin of the animal to internal organs, and a variety of methods can be utilized to perform 2P-IVM on these tissues. Here, we discuss the protocols and considerations for four of those 2P-IVM methods, namely tissue explant imaging, skin imaging, surgical exposure imaging, and multi-day window imaging. We carefully compare and explain in depth how to set up each method. Lastly, in the notes section we mention some alternative solutions for the 2P-IVM methods described. In conclusion, this protocol can be used as a guide towards deciding which 2P-IVM method to use and to enable the setup of this method.
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