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1.
Blood Purif ; 52(6): 600-608, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37062269

RESUMO

INTRODUCTION: The antibody response to SARS-CoV-2 vaccine in haemodialysis (HD) patients is diminished compared to healthy subjects. The aim of this study was to compare the presence of reactive SARS-CoV-2 antibodies in patients with high-flux HD and on-line haemodiafiltration (HDF) three and 6 months after the second dose of SARS-CoV-2 vaccine since previous studies indicate that a sustained antibody response correlates with protection from disease. METHODS: We included 216 HD patients of which 157 had on-line HDF and 59 high-flux HD and 46 health care workers as controls and studied the presence of reactive anti-spike IgG antibodies three and 6 months after the second dose of SARS-CoV-2 vaccine. Clinical features between the patient groups were similar, but patients with on-line HDF had significantly higher Kt/V. RESULTS: The percentage of participants with reactive antibodies was significantly lower in patients compared to controls, both three and 6 months after the second dose of vaccine. Furthermore, the proportion of patients with reactive anti-spike IgG ≥1.0 6 months after the second dose of vaccine was significantly higher in patients with on-line HDF compared to in patients with high-flux HD. In logistic regression analyses adjusted for several clinical features, the variables associated with presence of reactive anti-spike IgG at 3 months after the second dose of vaccine were lower age, HDF treatment, not being obese and not having a previous solid organ transplant. The two variables with the strongest influence on the presence of reactive anti-spike IgG levels 6 months after the second dose of vaccine were treatment with on-line HDF and not having immunosuppressive therapy. CONCLUSION: This is the first study to show that on-line HDF preserves the antibody response better than high-flux HD after vaccination with SARS-CoV-2 vaccine. Treatment strategies that sustain the vaccine response are essential to apply in this vulnerable group of patients.


Assuntos
COVID-19 , Hemodiafiltração , Humanos , Vacinas contra COVID-19 , Formação de Anticorpos , COVID-19/prevenção & controle , SARS-CoV-2 , Diálise Renal , Anticorpos Antivirais , Imunoglobulina G
2.
Biotechnol Bioeng ; 119(11): 3127-3139, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36017534

RESUMO

Messenger RNA (mRNA) vaccines are a new alternative to conventional vaccines with a prominent role in infectious disease control. These vaccines are produced in in vitro transcription (IVT) reactions, catalyzed by RNA polymerase in cascade reactions. To ensure an efficient and cost-effective manufacturing process, essential for a large-scale production and effective vaccine supply chain, the IVT reaction needs to be optimized. IVT is a complex reaction that contains a large number of variables that can affect its outcome. Traditional optimization methods rely on classic Design of Experiments methods, which are time-consuming and can present human bias or based on simplified assumptions. In this contribution, we propose the use of Machine Learning approaches to perform a data-driven optimization of an mRNA IVT reaction. A Bayesian optimization method and model interpretability techniques were used to automate experiment design, providing a feedback loop. IVT reaction conditions were found under 60 optimization runs that produced 12 g · L-1 in solely 2 h. The results obtained outperform published industry standards and data reported in literature in terms of both achievable reaction yield and reduction of production time. Furthermore, this shows the potential of Bayesian optimization as a cost-effective optimization tool within (bio)chemical applications.


Assuntos
Vacinas Sintéticas , Teorema de Bayes , Humanos , RNA Mensageiro/genética , Vacinas de mRNA
3.
J Proteome Res ; 18(3): 1278-1288, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30672297

RESUMO

Biofluid biomarkers of age-related macular degeneration (AMD) are still lacking, and their identification is challenging. Metabolomics is well-suited to address this need, and urine is a valuable accessible biofluid. This study aimed to characterize the urinary metabolomic signatures of patients with different stages of AMD and a control group (>50 years). It was a prospective, cross-sectional study, where subjects from two cohorts were included: 305 from Coimbra, Portugal (AMD patients n = 252; controls n = 53) and 194 from Boston, United States (AMD patients n = 147; controls n = 47). For all participants, we obtained color fundus photographs (for AMD staging) and fasting urine samples, which were analyzed using 1H nuclear magnetic resonance (NMR) spectroscopy. Our results revealed that in both cohorts, urinary metabolomic profiles differed mostly between controls and late AMD patients, but important differences were also found between controls and subjects with early AMD. Analysis of the metabolites responsible for these separations revealed that, even though distinct features were observed for each cohort, AMD was in general associated with depletion of excreted citrate and selected amino acids at some stage of the disease, suggesting enhanced energy requirements. In conclusion, NMR metabolomics enabled the identification of urinary signals of AMD and its severity stages, which might represent potential metabolomic biomarkers of the disease.


Assuntos
Biomarcadores/urina , Líquidos Corporais/metabolismo , Degeneração Macular/urina , Metabolômica , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Degeneração Macular/diagnóstico por imagem , Degeneração Macular/patologia , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade
4.
Biotechnol Bioeng ; 115(3): 586-596, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28986983

RESUMO

Rapid biocatalytic process development and intensification continues to be challenging with currently available methods. Chiral amino-alcohols are of particular interest as they represent key industrial synthons for the production of complex molecules and optically pure pharmaceuticals. (2S,3R)-2-amino-1,3,4-butanetriol (ABT), a building block for the synthesis of protease inhibitors and detoxifying agents, can be synthesized from simple, non-chiral starting materials, by coupling a transketolase- and a transaminase-catalyzed reaction. However, until today, full conversion has not been shown and, typically, long reaction times are reported, making process modifications and improvement challenging. In this contribution, we present a novel microreactor-based approach based on free enzymes, and we report for the first time full conversion of ABT in a coupled enzyme cascade for both batch and continuous-flow systems. Using the compartmentalization of the reactions afforded by the microreactor cascade, we overcame inhibitory effects, increased the activity per unit volume, and optimized individual reaction conditions. The transketolase-catalyzed reaction was completed in under 10 min with a volumetric activity of 3.25 U ml-1 . Following optimization of the transaminase-catalyzed reaction, a volumetric activity of 10.8 U ml-1 was attained which led to full conversion of the coupled reaction in 2 hr. The presented approach illustrates how continuous-flow microreactors can be applied for the design and optimization of biocatalytic processes.


Assuntos
Amino Álcoois/síntese química , Aminoaciltransferases/química , Proteínas de Escherichia coli/química , Escherichia coli/enzimologia , Transcetolase/química , Amino Álcoois/química , Catálise
5.
Ophthalmologica ; 240(1): 8-13, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29590656

RESUMO

OBJECTIVES: To describe the prevalence of lamellar hole-associated epiretinal proliferation (LHEP) and to correlate this finding with lamellar macular hole (LMH) morphology and prognosis after a surgical or conservative approach. METHODS: This is a retrospective multicenter case series comprising consecutive LMH patients followed for ≥6 months. Serial spectral-domain optical coherence tomographies were evaluated for the presence of epiretinal membrane (ERM) and LHEP, diameter of the LMH aperture, base, and floor thickness. Pars plana vitrectomy with ERM and internal limiting membrane peeling was performed in the surgical cases. RESULTS: A total of 62 eyes from 57 consecutive patients were included. Mean follow-up time was 27.1 ± 19.8 months. LHEP was observed in 33 (53.2%) eyes. Patients with LMH and LHEP presented a larger external diameter (p = 0.001) and thinner floors (p = 0.018). Twenty-seven (81.8%) of the patients with LMH and LHEP presented a degenerative intraretinal cavitation, compared to 23.3% in the non-LHEP group (p = 0.001). No differences were observed in visual performance or closure rate between the 2 groups after surgery or in the subset of patients followed conservatively. CONCLUSIONS: LHEP was correlated with the anatomical conformation of the LMH, yielding thinner floors and larger external diameters. However, it did not correlate with the anatomical or functional results, both in the patients who underwent surgery and in those managed conservatively.


Assuntos
Membrana Epirretiniana/etiologia , Perfurações Retinianas/complicações , Adulto , Idoso , Idoso de 80 Anos ou mais , Membrana Epirretiniana/diagnóstico por imagem , Membrana Epirretiniana/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Prognóstico , Perfurações Retinianas/diagnóstico por imagem , Perfurações Retinianas/cirurgia , Estudos Retrospectivos , Tomografia de Coerência Óptica , Acuidade Visual/fisiologia , Vitrectomia
6.
Ophthalmic Res ; 59(2): 88-97, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29065425

RESUMO

INTRODUCTION: We conducted a multimodal, cross-sectional evaluation. METHODS: Eyes were divided into 4 study groups: controls, early/intermediate age-related macular degeneration (AMD), fellow eyes of retinal angiomatous proliferation (RAP), and RAP eyes. Patients were evaluated with spectral-domain optical coherence tomography (OCT), enhanced depth imaging-OCT, and OCT angiography (OCTA). OCTA images were processed to generate maps of the vessel density and perfusion density of the superficial and deep retinal layers (SRL and DRL) and the choriocapillaris level (CL). The thickness of the outer nuclear layer and choroid was manually assessed. RESULTS: We included 135 eyes of 100 patients (51 controls, 30 AMD, 42 RAP, and 12 fellow eyes). The fellow eyes showed a significantly lower vascular perfusion of the SRL, DRL, and CL (p < 0.02) than the early/intermediate AMD and control eyes did. Similarly, RAP eyes presented a lower vascular perfusion of the DRL and CL (p < 0.05). Besides, structural analyses of the fellow eyes and RAP eyes revealed a significantly higher prevalence of macular pigmentary changes, atrophy of the retinal pigment epithelium, hyperreflective "clumps" above flat drusen, amongst others, than early/intermediate AMD and control eyes (p < 0.05). CONCLUSION: We present the first report on the OCTA analysis of the fellow eye of patients with RAP. The reduced perfusion density and vessel density observed contributes, in association with clearly defined structural changes, to a wider characterization of RAP as a distinctive phenotype.


Assuntos
Degeneração Macular/patologia , Neovascularização Retiniana/patologia , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Neovascularização de Coroide/patologia , Estudos Transversais , Feminino , Angiofluoresceinografia , Humanos , Degeneração Macular/diagnóstico por imagem , Pigmento Macular/análise , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Drusas Retinianas/patologia , Neovascularização Retiniana/diagnóstico por imagem , Epitélio Pigmentado da Retina/patologia , Vasos Retinianos/diagnóstico por imagem , Tomografia de Coerência Óptica
7.
Ophthalmic Res ; 55(3): 145-51, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26735700

RESUMO

PURPOSE: To assess and describe sequential morphological changes in the choroidal neovascularization (CNV) net using optical coherence tomography angiography (OCTA) in patients undergoing treatment with intravitreal antivascular endothelial growth factor (VEGF). METHODS: Prospective cohort study. OCTA was performed sequentially: before (t0), 1 h (t1), 1 week (t2) and 1 month after the injection (t3), using Avanti RTVue XR equipped with the AngioVue® software (Optovue, Calif., USA). All images were classified by two independent graders. RESULTS: Ten eyes of 10 patients, with a mean age of 72.4 ± 10.5 years, were included. CNV morphology was described as tree-like in 5 eyes, glomerular in 1 and fragmented in 4. A fibrovascular capsule surrounding the CNV net was found in 4 eyes and a feeder trunk was noticed in 6. No changes were observed at t1. Loss of peripheral capillaries, vessel fragmentation and decreased vessel density were evident in 8 eyes at t2. The CNV capillary density and the peripheral anastomosis increased in all of these at t3. Two eyes remained unchanged through the whole length of follow-up. CONCLUSIONS: Significant changes in the CNV net can be observable in OCTA at least 1 week after intravitreal anti-VEGF. The safety of frequent examinations may provide a method of gauging treatment effects.


Assuntos
Inibidores da Angiogênese/administração & dosagem , Bevacizumab/administração & dosagem , Neovascularização de Coroide/tratamento farmacológico , Ranibizumab/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Corioide/irrigação sanguínea , Neovascularização de Coroide/patologia , Feminino , Angiofluoresceinografia/métodos , Humanos , Injeções Intravítreas , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Retina/patologia , Tomografia de Coerência Óptica/métodos , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Acuidade Visual
8.
Ophthalmic Res ; 55(3): 119-25, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26671015

RESUMO

PURPOSE: To evaluate the long-term efficacy of ranibizumab in the treatment of retinal angiomatous proliferation (RAP) and to identify predictors of functional outcome. METHODS: Retrospective case series comprised 79 eyes of 68 consecutive patients with RAP followed up ≥36 months. Primary end-points were best-corrected visual acuity (BCVA) and central macular thickness (CMT) variation at 36 months and at the last visit. RESULTS: Mean follow-up time was 59.8 ± 16.0 months. All eyes were treated with pro re nata ranibizumab, with (n = 33) or without (n = 46) photodynamic therapy (PDT). Stabilization or improvement in BCVA was observed in 50.6% of the patients at 36 months, and in 40.5% at the end of the follow-up, where 20.3% preserved reading vision. A significant decrease in CMT was observed at 36 months (p < 0.001), but not at the end of the follow-up. Geographic atrophy (GA) was present in 59.5% of the eyes at the final visit. Baseline subretinal fluid was associated with better visual outcomes (p = 0.001). Results of combination treatment with intravitreal ranibizumab and PDT did not significantly differ from ranibizumab monotherapy. CONCLUSION: Modest functional outcomes can be expected from the long-term treatment of RAP lesions in clinical practice, most likely due to the advent of GA. Baseline subretinal fluid positively correlated with final BCVA.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Ranibizumab/uso terapêutico , Neovascularização Retiniana/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Feminino , Seguimentos , Humanos , Injeções Intravítreas , Degeneração Macular/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Acuidade Visual
9.
Mycopathologia ; 181(11-12): 879-884, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27631818

RESUMO

We report a case of a keratitis associated with a Fusarium penzigii-a Fusarium dimerum species complex (FDSC)-in a 81-year-old woman after a corneal trauma with a tree branch. At patient admittance, slit lamp biomicroscopy revealed an exuberant chemosis, an inferior corneal ulcer with an associated inflammatory infiltrate, a central corneal abscess, bullous keratopathy and posterior synechiae. Corneal scrapes were obtained for identification of bacteria and fungi, and the patient started antibiotic treatment on empirical basis. Few days later, the situation worsened with the development of hypopyon. By that time, Fusarium was identified in cultures obtained from corneal scrapes and the patient started topical amphotericin B 0.15 %. Upon the morphological identification of the Fusarium as a FDSC, and since there was no clinical improvement, the treatment with amphotericin B was suspended and the patient started voriconazole 10 mg/ml, eye drops, hourly and voriconazole 200 mg iv, every 12 h for 1 month. The hypopyon resolved and the inflammatory infiltrate improved, but the abscess persisted at the last follow-up visit. The molecular identification revealed that the FDSC was a F. penzigii.


Assuntos
Lesões da Córnea/complicações , Fusariose/diagnóstico , Fusariose/patologia , Fusarium/isolamento & purificação , Ceratite/etiologia , Ceratite/patologia , Idoso de 80 Anos ou mais , Antifúngicos/administração & dosagem , Feminino , Fusariose/microbiologia , Fusarium/classificação , Humanos , Ceratite/microbiologia , Soluções Oftálmicas/administração & dosagem , Resultado do Tratamento , Voriconazol/administração & dosagem
10.
J Chem Technol Biotechnol ; 91(3): 823-831, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27478291

RESUMO

BACKGROUND: Microbioreactors have emerged as a new tool for early bioprocess development. The technology has advanced rapidly in the last decade and obtaining real-time quantitative data of process variables is nowadays state of the art. In addition, control over process variables has also been achieved. The aim of this study was to build a microbioreactor capable of controlling dissolved oxygen (DO) concentrations and to determine oxygen uptake rate in real time. RESULTS: An oscillating jet driven, membrane-aerated microbioreactor was developed without comprising any moving parts. Mixing times of ∼7 s, and kLa values of ∼170 h-1 were achieved. DO control was achieved by varying the duty cycle of a solenoid microvalve, which changed the gas mixture in the reactor incubator chamber. The microbioreactor supported Saccharomyces cerevisiae growth over 30 h and cell densities of 6.7 gdcw L-1. Oxygen uptake rates of ∼34 mmol L-1 h-1 were achieved. CONCLUSION: The results highlight the potential of DO-controlled microbioreactors to obtain real-time information on oxygen uptake rate, and by extension on cellular metabolism for a variety of cell types over a broad range of processing conditions. © 2015 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

11.
Appl Microbiol Biotechnol ; 98(12): 5599-606, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24599310

RESUMO

Bacterial cells are known to adapt to challenging environmental conditions such as osmotic stress. However, most of the work done in this field describes the adaptation of growing populations where the new generations acquire traits that improve their ability to survive. In the present study, the responses of Rhodococcus erythropolis cells within the first 30 min after exposure to osmotic stress caused by sodium chloride were studied. The cells changed the total lipid fatty acid composition and also the net surface charge in the 30 min following exposure. Surprisingly, the cells produced a high percentage of polyunsaturated fatty acids. In the presence of 7.5 % NaCl, these polyunsaturated fatty acids, mainly eicosapentaenoic acid (C20:5ω3), arachidonic acid (C20:4ω6) and docosapentaenoic acid (C22:5ω3), comprise more than 36 % of the total fatty acids. The possible function of these very uncommon fatty acids in bacteria could be the decrease in the number of negatively charged groups in ion channels resulting in a repellence of the NaCl.


Assuntos
Ácidos Graxos Insaturados/biossíntese , Pressão Osmótica , Rhodococcus/efeitos dos fármacos , Sais/metabolismo , Estresse Fisiológico , Rhodococcus/fisiologia , Fatores de Tempo
12.
Sci Rep ; 14(1): 9655, 2024 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-38671016

RESUMO

The manufacturing of mRNA vaccines relies on cell-free based systems that are easily scalable and flexible compared with the traditional vaccine manufacturing processes. Typically, standard processes yield 2 to 5 g L-1 of mRNA, with recent process optimisations increasing yields to 12 g L-1. However, increasing yields can lead to an increase in the production of unwanted by-products, namely dsRNA. It is therefore imperative to reduce dsRNA to residual levels in order to avoid intensive purification steps, enabling cost-effective manufacturing processes. In this work, we exploit sequence modifications downstream of the T7 RNA polymerase promoter to increase mRNA yields whilst simultaneously minimising dsRNA. In particular, transcription performance was optimised by modifying the sequence downstream of the T7 promoter with additional AT-rich sequences. We have identified variants that were able to produce higher amounts of mRNA (up to 14 g L-1) in 45 min of reaction. These variants exhibited up to a 30% reduction in dsRNA byproduct levels compared to a wildtype T7 promoter, and have similar EGFP protein expression. The results show that optimising the non-coding regions can have an impact on mRNA production yields and quality, reducing overall manufacturing costs.


Assuntos
RNA Polimerases Dirigidas por DNA , Regiões Promotoras Genéticas , RNA Mensageiro , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Polimerases Dirigidas por DNA/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo , Bacteriófago T7/genética , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/metabolismo , Vacinas de mRNA
13.
J Chromatogr A ; 1730: 465110, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38941794

RESUMO

Maximizing product quality attributes by optimizing process parameters and performance attributes is a crucial aspect of bioprocess chromatography process design. Process parameters include but are not limited to bed height, eluate cut points, and elution pH. An under-characterized chromatography process parameter for protein A chromatography is process temperature. Here, we present a mechanistic understanding of the effects of temperature on the protein A purification of a monoclonal antibody (mAb) using a commercial chromatography resin for batch and continuous counter-current systems. A self-designed 3D-printed heating jacket controlled the 1 mL chromatography process temperature during the loading, wash, elution, and cleaning-in-place (CIP) steps. Batch loading experiments at 10, 20, and 30 °C demonstrated increased dynamic binding capacity (DBC) with temperature. The experimental data were fit to mechanistic and correlation-based models that predicted the optimal operating conditions over a range of temperatures. These model-based predictions optimized the development of a 3-column temperature-controlled periodic counter-current chromatography (TCPCC) and were validated experimentally. Operating a 3-column TCPCC at 30 °C led to a 47% increase in DBC relative to 20 °C batch chromatography. The DBC increase resulted in a two-fold increase in productivity relative to 20 °C batch. Increasing the number of columns to the TCPCC to optimize for increasing feed concentration resulted in further improvements to productivity. The feed-optimized TCPCC showed a respective two, three, and four-fold increase in productivity at feed concentrations of 1, 5, and 15 mg/mL mAb, respectively. The derived and experimentally validated temperature-dependent models offer a valuable tool for optimizing both batch and continuous chromatography systems under various operating conditions.

14.
Biotechnol Prog ; : e3470, 2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38613384

RESUMO

Tumor spheroid models have garnered significant attention in recent years as they can efficiently mimic in vivo models, and in addition, they offer a more controlled and reproducible environment for evaluating the efficacy of cancer drugs. In this study, we present the design and fabrication of a micromold template to form multicellular spheroids in a high-throughput and controlled-sized fashion. Briefly, polydimethylsiloxane-based micromolds at varying sizes and geometry were fabricated via soft lithography using 3D-printed molds as negative templates. The efficiency of spheroid formation was assessed using GFP-expressing human embryonic kidney 293 cells (HEK-293). After 7 days of culturing, circularity and cell viability of spheroids were >0.8 and 90%, respectively. At 1500 cells/microwell of cell seeding concentration, the spheroids were 454 ± 15 µm, 459 ± 7 µm, and 451 ± 18 µm when cultured in microwells with the diameters of 0.4, 0.6, and 0.8 µm, respectively. Moreover, the distance between each microwell and surfactant treatment before cell seeding notably impacted the uniform spheroid formation. The centrifugation was the key step to collect cells on the bottom of the microwells. Our findings were further verified using a commercial microplate. Furthermore, Monte Carlo simulation confirmed the seeding conditions where the spheroids could be formed. This study showed prominent steps in investigating spheroid formation, thereby leveraging the current know-how on the mechanism of tumor growth.

15.
ACS Omega ; 9(21): 22619-22624, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38826531

RESUMO

DNA origami is an emerging technology that can be used as a nanoscale platform in numerous applications ranging from drug delivery systems to biosensors. The DNA nanostructures are assembled from large single-stranded DNA (ssDNA) scaffolds, ranging from hundreds to thousands of nucleotides and from short staple strands. Scaffolds are usually obtained by asymmetric PCR (aPCR) or Escherichia coli infection/transformation with phages or phagemids. Scaffold quantification is typically based on agarose gel electrophoresis densitometry for molecules obtained by aPCR, or by UV absorbance, in the case of scaffolds obtained by infection or transformation. Although these methods are well-established and easy-to-apply, the results obtained are often inaccurate due to the lack of selectivity and sensitivity in the presence of impurities. Herein, we present an HPLC method based on ion-pair reversed-phase (IP-RP) chromatography to quantify DNA scaffolds. Using IP-RP chromatography, ssDNA products (449 and 1000 nt) prepared by aPCR were separated from impurities and from the double stranded (ds) DNA byproduct. Additionally, both ss and dsDNA were quantified with high accuracy. The method was used to guide the optimization of the production of ssDNA by aPCR, which targeted the maximization of the ratio of ssDNA to dsDNA obtained. Moreover, ssDNA produced from phage infection of E. coli cells was also quantified by IP-RP using commercial ssDNA from the M13mp18 phage as a standard.

16.
Methods Mol Biol ; 2704: 201-219, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37642846

RESUMO

Small-scale devices are routinely used as low-cost miniaturized bioreactors due to the large number of experiments that can be conducted simultaneously under similar conditions and replicate all functions of bench-scale reactors at dramatically smaller volumes. Microtiter plates, due to the standard footprint, can be integrated with liquid handling systems and associated equipment, expanding considerably their application and use. However, care has to be taken to operate the microtiter plates in optimized mixing and oxygen transfer conditions, preventing medium evaporation in prolonged experiment runs. Recently, to increase data quality, microbioreactors have emerged as an alternative to shaken systems. These systems offer higher degree of control over key process variables and when combined with sensing technology increase dramatically the reliability of translational process data. In this chapter, we describe the production of 4-androstene-3,17-dione (androstenedione (AD)), a key pharmaceutical steroid intermediate, by Mycobacterium sp. NRRL B-3805 via the selective cleavage of the side-chain of ß-sitosterol using 24-well microtiter plates and microfluidic microbioreactors.


Assuntos
Reatores Biológicos , Microfluídica , Reprodutibilidade dos Testes , Androstenodiona
17.
Artigo em Inglês | MEDLINE | ID: mdl-37649818

RESUMO

Background: Occlusal splints with sensors help in the bruxism diagnosis and monitoring, by recording the patient's bite force. The aim of this study was to evaluate the accuracy of a pressure sensor when it is covered with different thicknesses of a 3D printing resin (Anycubic 405nm Translucent Green UV Resin, Anycubic, UK). Methods: In this preliminary study, the evaluated sensor (FlexiForce A201 Sensor, Tekscan) was firstly calibrated without any type of cover material, and later tested with 3D printing resin with different thicknesses (1 mm, 1.15 mm, 1.4 mm and 1.6 mm). The load tests were performed by a force tester (MultiTest 2.5 dV, Mecmesin). Results: When the pressure sensor was covered with resin of 1mm and 1.6 mm thick specimens, a higher difference was found between the applied load and the corresponding sensor reading. Conclusion: It was concluded that it is possible to use this type of pressure sensor and that it showed better accuracy with the 1.15 mm and 1.4 mm 3D printing resin covering.

18.
Porto Biomed J ; 8(2): e208, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37152633

RESUMO

Background: Total knee arthroplasty (TKA) is one of the most frequently performed orthopedic procedures. The correct positioning and alignment of the components significantly affects prosthesis survival. Considering the current controversy regarding the target of postoperative alignment of TKA, this study evaluated the tension at tibial component interface using two numerical methods. Methods: The stress of the prosthesis/bone interface of the proximal tibial component was evaluated using two numerical methods: the finite element method (FEM) and the new meshless method: natural neighbor radial point interpolation method (NNRPIM). The construction of the model was based on Zimmers NexGen LPS-Flex Mobile® prosthesis and simulated the forces by using a free-body diagram. Results: Tibiofemoral mechanical axis (TFMA) for which a higher number of nodes are under optimal mechanical tension is between 1° valgus 2° varus. For values outside the interval, there are regions under the tibial plate at risk of bone absorption. At the extremities of the tibial plate of the prosthesis, both medial and lateral, independent of the alignment, are under a low stress. In all nodes evaluated for all TFMA, the values of the effective stresses were higher in the NNRPIM when compared with the FEM. Conclusion: Through this study, we can corroborate that the optimal postoperative alignment is within the values that are currently considered of 0 ± 3° varus. It was verified that the meshless methods obtain smoother and more conservative results, which may make them safer when transposed to the clinical practice.

19.
Nefrologia (Engl Ed) ; 43(2): 197-203, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36437202

RESUMO

INTRODUCTION: There is scarce clinical experience with etelcalcetide in patients with secondary hyperparathyroidism uncontrolled with cinacalcet. The effect of etelcalcetide on serum sclerostin levels remains to be clarified. MATERIALS AND METHODS: Prospective cohort study in prevalent hemodialysis patients with uncontrolled sHPT under cinacalcet for at least 3 months, mean parathyroid hormone (PTH)>800pg/mL and calcium (Ca)>8.3mg/dL. Etelcalcetide 5mg IV/HD was initiated after cinacalcet washout. Levels of PTH, Ca, and phosphorus (Pi) followed monthly for 6 months. Plasma sclerostin levels measured before etelcalcetide treatment and after 6 months. RESULTS: Thirty-four patients were enrolled, 19 (55.9%) male gender. Mean age 60.7 (± 12.3) years; median time on HD 82.5 (7-296) months and median cinacalcet dose was 180mg/week (Interquartile Range: 180-270). Serum Ca, Pi and PTH levels showed a significant reduction after etelcalcetide treatment from 8.8mg/dL, 5.4mg/dL and 1005pg/mL to 8.1mg/dL (p=0.08), 4.9mg/dL (p=0.01) and 702pg/mL (p<0.001), respectively. Median etelcalcetide dose remained at 5mg/HD. Plasma sclerostin concentration increased from 35.66pmol/L (IQR11.94-54.58) to 71.05pmol/L (IQR54.43-84.91) (p<0.0001). CONCLUSION: Etelcalcetide improved sHPT control in this group of patients, previously under cinacalcet treatment, and significantly increased plasma sclerostin concentration. The impact of etelcalcetide treatment on sclerostin levels is a novel finding.

20.
Adv Biochem Eng Biotechnol ; 179: 211-246, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33624135

RESUMO

The implementation of continuous-flow transformations in biocatalysis has received remarkable attention in the last few years. Flow microfluidic reactors represent a crucial technological tool that has catalyzed this trend by promising tremendous improvement in biocatalytic processes across a host of different levels, including bioprocess development, intensification of reactions, implementation of new methods of reaction screening, and enhanced reaction scale-up. However, the full realization of this promise requires a synergy between these biocatalytic reaction features and the design and operation of microfluidic reactors. Here an overview on the different applications of flow biocatalysis is provided according to the format of the enzyme used: free vs immobilized form. Until now, flow biocatalysis has been implemented on a case-by-case approach but challenges and limitations are discussed in order to be overcome, and making continuous-flow microfluidic reactors as universal tool a reality.


Assuntos
Enzimas Imobilizadas , Microfluídica , Biocatálise , Reatores Biológicos , Enzimas Imobilizadas/metabolismo
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