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1.
Int J Cardiol ; 398: 131599, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37979786

RESUMO

INTRODUCTION: Amyloid light-chain amyloidosis is a rare condition characterized by the abnormal production of immunoglobulin light chain that misshape and form amyloid fibrils. Over time, these amyloid deposits can accumulate slowly, causing dysfunction in organs and tissues. Early identification is crucial to ensure optimal treatment. We aim to identify a better marker of cardiac amyloidosis, using advanced echocardiography, to improve diagnosis and the timing of available treatments. MATERIALS AND METHODS: 108 consecutive hematological patients (32, 30% female and 76, 70% male) with a plasma cell disorder referred to our Cardiological center underwent ECG, first and second-level echocardiography (Speckle Tracking) and complete biochemical profile. The best predictors of ALCA (AUC ≥ 0.8) were included in a further analysis stratified by AL score. RESULTS: At ROC analysis, the best bio-humoral predictors for the diagnosis of ALCA were Nt-pro-BNP (AUC: 0.97; p < 0.01) and Hs-Tn (AUC: 0.87; p < 0.01). Regarding echocardiography, the best diagnostic predictors were left atrial stiffness (LAS) (AUC: 0.83; p < 0.01) for the left atrium; free wall thickness for the right ventricle (AUC: 0.82; <0.01); left ventricular global longitudinal strain (LVGLS) (AUC: 0.92; p < 0.01) and LVMi (AUC 0.80; p < 0.001) for the left ventricle; and AL-score (AUC 0.83 p < 0.01). In patients with AL-SCORE < 1, LAS (AUC 0.86 vs AUC 0.79), LVGLS (AUC 0.92 vs AUC 0.86) and LV mass (AUC 0.91 vs AUC 0.72) had better diagnostic accuracy than patients with higher AL-score (AL SCORE ≥ 1). CONCLUSION: Multi-parametric imaging approach with LVGLS and LAS may be helpful for detecting early cardiac involvement in AL amyloidosis.


Assuntos
Amiloidose , Amiloidose de Cadeia Leve de Imunoglobulina , Humanos , Masculino , Feminino , Amiloidose de Cadeia Leve de Imunoglobulina/diagnóstico por imagem , Plasmócitos , Ecocardiografia/métodos , Amiloidose/diagnóstico por imagem , Diagnóstico Precoce , Função Ventricular Esquerda
3.
Methods Mol Biol ; 2622: 265-276, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36781769

RESUMO

It is being increasingly recognized that therapeutics need to be delivered to specific organelle targets within cells. Liposomes are versatile lipid-based drug delivery vehicles that can be surface modified to deliver the loaded cargo to specific subcellular locations within the cell. Hence, the development of such technology requires a means of measuring subcellular distribution by utilizing imaging techniques that can visualize and quantitate the extent of this subcellular localization. The apparent increase of resolution along the Z-axis offered by confocal microscopy makes this technique suitable for such studies. In this chapter, we will describe the application of confocal laser scanning microscopy (CLSM) to determine the subcellular distribution of fluorescently labeled mitochondriotropic liposomes.


Assuntos
Sistemas de Liberação de Medicamentos , Lipossomos , Mitocôndrias , Microscopia Confocal/métodos
4.
Nat Plants ; 8(11): 1289-1303, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36357524

RESUMO

Rhamnogalacturonan I (RG-I) is a major plant cell wall pectic polysaccharide defined by its repeating disaccharide backbone structure of [4)-α-D-GalA-(1,2)-α-L-Rha-(1,]. A family of RG-I:Rhamnosyltransferases (RRT) has previously been identified, but synthesis of the RG-I backbone has not been demonstrated in vitro because the identity of Rhamnogalacturonan I:Galaturonosyltransferase (RG-I:GalAT) was unknown. Here a putative glycosyltransferase, At1g28240/MUCI70, is shown to be an RG-I:GalAT. The name RGGAT1 is proposed to reflect the catalytic activity of this enzyme. When incubated together with the rhamnosyltransferase RRT4, the combined activities of RGGAT1 and RRT4 result in elongation of RG-I acceptors in vitro into a polymeric product. RGGAT1 is a member of a new GT family categorized as GT116, which does not group into existing GT-A clades and is phylogenetically distinct from the GALACTURONOSYLTRANSFERASE (GAUT) family of GalA transferases that synthesize the backbone of the pectin homogalacturonan. RGGAT1 has a predicted GT-A fold structure but employs a metal-independent catalytic mechanism that is rare among glycosyltransferases with this fold type. The identification of RGGAT1 and the 8-member Arabidopsis GT116 family provides a new avenue for studying the mechanism of RG-I synthesis and the function of RG-I in plants.


Assuntos
Arabidopsis , Pectinas , Polimerização , Pectinas/metabolismo , Arabidopsis/metabolismo , Glicosiltransferases/metabolismo , Polissacarídeos/metabolismo
5.
Biotechnol Biofuels Bioprod ; 15(1): 23, 2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35227303

RESUMO

BACKGROUND: Terrestrial plant biomass is the primary renewable carbon feedstock for enabling transition to a sustainable bioeconomy. Consolidated bioprocessing (CBP) by the cellulolytic thermophile Clostridium thermocellum offers a single step microbial platform for production of biofuels and biochemicals via simultaneous solubilization of carbohydrates from lignocellulosic biomass and conversion to products. Here, solubilization of cell wall cellulosic, hemicellulosic, and pectic polysaccharides in the liquor and solid residues generated during CBP of poplar biomass by C. thermocellum was analyzed. RESULTS: The total amount of biomass solubilized in the C. thermocellum DSM1313 fermentation platform was 5.8, 10.3, and 13.7% of milled non-pretreated poplar after 24, 48, and 120 h, respectively. These results demonstrate solubilization of 24% cellulose and 17% non-cellulosic sugars after 120 h, consistent with prior reports. The net solubilization of non-cellulosic sugars by C. thermocellum (after correcting for the uninoculated control fermentations) was 13 to 36% of arabinose (Ara), xylose (Xyl), galactose (Gal), mannose (Man), and glucose (Glc); and 15% and 3% of fucose and glucuronic acid, respectively. No rhamnose was solubilized and 71% of the galacturonic acid (GalA) was solubilized. These results indicate that C. thermocellum may be selective for the types and/or rate of solubilization of the non-cellulosic wall polymers. Xyl, Man, and Glc were found to accumulate in the fermentation liquor at levels greater than in uninoculated control fermentations, whereas Ara and Gal did not accumulate, suggesting that C. thermocellum solubilizes both hemicelluloses and pectins but utilizes them differently. After five days of fermentation, the relative amount of Rha in the solid residues increased 21% indicating that the Rha-containing polymer rhamnogalacturonan I (RG-I) was not effectively solubilized by C. thermocellum CBP, a result confirmed by immunoassays. Comparison of the sugars in the liquor versus solid residue showed that C. thermocellum solubilized hemicellulosic xylan and mannan, but did not fully utilize them, solubilized and appeared to utilize pectic homogalacturonan, and did not solubilize RG-I. CONCLUSIONS: The significant relative increase in RG-I in poplar solid residues following CBP indicates that C. thermocellum did not solubilize RG-I. These results support the hypothesis that this pectic glycan may be one barrier for efficient solubilization of poplar by C. thermocellum.

6.
Plant J ; 109(6): 1441-1456, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34908202

RESUMO

Homogalacturonan (HG), the most abundant pectic glycan, functions as a cell wall structural and signaling molecule essential for plant growth, development and response to pathogens. HG exists as a component of pectic homoglycans, heteroglycans and glycoconjugates. HG is synthesized by members of the GALACTURONOSYLTRANSFERASE (GAUT) family. UDP-GalA-dependent homogalacturonan:galacturonosyltransferase (HG:GalAT) activity has previously been demonstrated for GAUTs 1, 4 and 11, as well as the GAUT1:GAUT7 complex. Here, we show that GAUTs 10, 13 and 14 are also HG:GalATs and that GAUTs 1, 10, 11, 13, 14 and 1:7 synthesize polymeric HG in vitro. Comparison of the in vitro HG:GalAT specific activities of the heterologously-expressed proteins demonstrates GAUTs 10 and 11 with the lowest, GAUT1 and GAUT13 with moderate, and GAUT14 and the GAUT1:GAUT7 complex with the highest HG:GalAT activity. GAUT13 and GAUT14 are also shown to de novo synthesize (initiate) HG synthesis in the absence of exogenous HG acceptors, an activity previously demonstrated for GAUT1:GAUT7. The rate of de novo HG synthesis by GAUT13 and GAUT14 is similar to their acceptor dependent HG synthesis, in contrast to GAUT1:GAUT7 for which de novo synthesis occurred at much lower rates than acceptor-dependent synthesis. The results suggest a unique role for de novo HG synthesis by GAUTs 13 and 14. The reducing end of GAUT13-de novo-synthesized HG has covalently attached UDP, indicating that UDP-GalA serves as both a donor and acceptor substrate during de novo HG synthesis. The functional significance of unique GAUT HG:GalAT catalytic properties in the synthesis of different pectin glycan or glycoconjugate structures is discussed.


Assuntos
Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Parede Celular/metabolismo , Glucuronosiltransferase/metabolismo , Glicosiltransferases/metabolismo , Oligossacarídeos/metabolismo , Pectinas/metabolismo
7.
Front Plant Sci ; 11: 585774, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33072156

RESUMO

The major cell wall pectic glycan homogalacturonan (HG) is crucial for plant growth, development, and reproduction. HG synthesis occurs in the Golgi and is catalyzed by members of the galacturonosyltransferase (GAUT) family with GAUT1 being the archetypal and best studied family member. In Arabidopsis suspension culture cells and tobacco leaves, the Golgi localization of Arabidopsis GAUT1 has been shown to require protein-protein interactions with its homolog GAUT7. Here we show that in pollen tubes GAUT5 and GAUT6, homologs of GAUT7, also target GAUT1 to the Golgi apparatus. Pollen tube germination and elongation in double homozygous knock-out mutants (gaut5 gaut6, gaut5 gaut7, and gaut6 gaut7) are moderately impaired, whereas gaut5 -/- gaut6 -/- gaut7 +/- triple mutant is severely impaired and male infertile. Amounts and distributions of methylesterified HG in the pollen tube tip were severely distorted in the double and heterozygous triple mutants. A chimeric protein comprising GAUT1 and a non-cleavable membrane anchor domain was able to partially restore pollen tube germination and elongation and to reverse male sterility in the triple mutant. These results indicate that GAUT5, GAUT6, and GAUT7 are required for synthesis of native HG in growing pollen tubes and have critical roles in pollen tube growth and male fertility in Arabidopsis.

9.
J Manag Care Spec Pharm ; 26(6): 723-727, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32463774

RESUMO

BACKGROUND: The North Carolina Cancer Hospital at the University of North Carolina Medical Center serves patients with a variety of malignant conditions and discharges more than 130 patients each month. Processes to improve transitions of care prompted implementation of a first-cycle, pharmacist-led chemotherapy consultation service on the inpatient oncology units. This process provides education to improve patient engagement and activation. High patient activation has been associated with better patient outcomes; poor patient activation has been associated with increased health care costs. OBJECTIVE: To determine the effect of pharmacist-led comprehensive chemotherapy consultation services on adherence to outpatient follow-up appointments within 30 days of discharge. METHODS: This was a single-center, retrospective chart review. This study consisted of 2 groups: adult patients who received comprehensive consultation services between April 2017 and September 2017 and a 2:1 historical group of adult control patients randomly selected from a list of patients who received their first cycle of chemotherapy during a hospital admission between April 2014 and April 2017. The primary endpoint was the effect of comprehensive consultation services on adherence to outpatient follow-up appointments within 1 month after discharge. RESULTS: Ninety-six patients were included in this study. The percentage of appointments attended was 98.0% for the intervention group and 92.3% for the control group (P = 0.0018). CONCLUSIONS: This study demonstrates that pharmacy consultation in the inpatient oncology setting is associated with improved adherence to outpatient appointments within 30 days of discharge. This represents the first published data on pharmacist interventions resulting in improved outpatient appointment adherence. DISCLOSURES: Funding for this study was contributed by the Hematology/Oncology Pharmacy Association (HOPA). This publication was also supported by Grant Number UL1TR002489 from the National Center for Advancing Translational Sciences at the National Institutes of Health. Auten reports fees from PTCE and ASHP/ACCP, unrelated to this study. Clark reports consulting fees from Ellion Benson Research, unrelated to this study. The other authors do not have any conflicts of interest to report. This study was presented as a trainee poster on April 5, 2019, at the HOPA Ahead 15th Annual Conference in Fort Worth, TX.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Farmacêuticos/organização & administração , Serviço de Farmácia Hospitalar/organização & administração , Encaminhamento e Consulta/organização & administração , Adulto , Assistência ao Convalescente/organização & administração , Assistência ao Convalescente/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Assistência Ambulatorial/estatística & dados numéricos , Agendamento de Consultas , Feminino , Hospitais Universitários/organização & administração , Hospitais Universitários/estatística & dados numéricos , Humanos , Masculino , Adesão à Medicação/estatística & dados numéricos , Pessoa de Meia-Idade , North Carolina , Ambulatório Hospitalar/organização & administração , Ambulatório Hospitalar/estatística & dados numéricos , Papel Profissional , Estudos Retrospectivos , Adulto Jovem
11.
Mol Divers ; 24(1): 155-166, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30875060

RESUMO

Benzisoxazoles represent an important pharmacophore in medicinal chemistry. Recently, an unexpected formation of symmetric 3-substituted 2,1-benzisoxazoles through reduction of 5-(2-nitrobenzylidene)barbiturates has been described. This reductive intramolecular heterocyclization probably involves a nitroso intermediary. To improve the previous reaction conditions, the nature of the reducing agent and additives, reaction time and solvents were evaluated. By applying the optimized conditions, several symmetric and unsymmetric barbiturates C5-coupled with 2,1-benzisoxazoles were prepared with an yield of 52-87%. From this set, seven compounds were novel and the unsymmetric nature of the (thio)barbituric acid moiety was explored. For that, the total synthesis, starting from the respective urea or thiourea, was successfully performed, and 11 thiobarbiturates, benzylidene barbiturate and thiobarbiturate precursors are described.


Assuntos
Azóis/química , Barbitúricos/síntese química , Benzeno/química , Técnicas de Química Sintética , Solventes , Análise Espectral , Temperatura , Fatores de Tempo
12.
Tech Coloproctol ; 23(5): 471-477, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31069556

RESUMO

BACKGROUND: The aim of this study was to evaluate the feasibility of the Versius surgical robotic system for transanal total mesorectal excision (taTME) in a preclinical setting. METHODS: Dry laboratory and cadaveric sessions were first conducted for three experienced colorectal surgeons in order to gain familiarity with the modular surgical system and the robotic workstation. After introduction, the system was configured to allow for synchronous, totally robotic taTME in a cadaver. RESULTS: Using the modular robotic system, one surgeon performed the abdominal portion of the operation, including colonic mobilization and vascular pedicle ligation while simultaneously a second surgeon performed the transanal portion of the operation to the point of rendezvous at the peritoneal reflection, where the operation was completed cooperatively. The operation was successfully completed in 195 min demonstrating preclinical feasibility of this unique approach with an emerging robotic system. CONCLUSIONS: This is the first preclinical assessment of the Versius surgical robotic system for taTME. The ability to work simultaneously carries the theoretical advantage of reducing surgical time and thereby reducing overall operative costs. It may also allow surgeons to maintain focus on critical parts of the operation by halving the fatigue associated with long, complex cases such as taTME.


Assuntos
Procedimentos Cirúrgicos Robóticos/educação , Procedimentos Cirúrgicos Robóticos/instrumentação , Cirurgia Endoscópica Transanal/educação , Cirurgia Endoscópica Transanal/instrumentação , Cadáver , Competência Clínica , Desenho de Equipamento , Humanos
13.
Tech Coloproctol ; 23(1): 53-63, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30656579

RESUMO

BACKGROUND: Real-time stereotactic navigation for transanal total mesorectal excision has been demonstrated to be feasible in small pilot series using laparoscopic techniques. The possibility of real-time stereotactic navigation coupled with robotics has not been previously explored in a clinical setting. METHODS: After pre-clinical assessment, and configuration of a robotic-assisted navigational system, two patients with locally advanced rectal cancer were selected for enrollment into a pilot study designed to assess the feasibility of navigation coupled with the robotic da Vinci Xi platform via TilePro interface. In one case, fluorescence-guided surgery was also used as an adjunct for structure localization, with local administration of indocyanine green into the ureters and at the tumor site. RESULTS: Each operation was successfully completed with a robotic-assisted approach; image-guided navigation provided computed accuracy of ± 4.5 to 4.6 mm. The principle limitation encountered was navigation signal dropout due to temporary loss of direct line-of-sight with the navigational system's infrared camera. Subjectively, the aid of navigation assisted the operating surgeon in identifying critical anatomical planes. The combination of fluorescence with image-guided surgery further augmented the surgeon's perception of the operative field. CONCLUSIONS: The combination of stereotactic navigation and robotic surgery is feasible, although some limitations and technical challenges were observed. For complex surgery, the addition of navigation to robotics can improve surgical precision. This will likely represent the next step in the evolution of robotics and in the development of digital surgery.


Assuntos
Laparoscopia/métodos , Neuronavegação/métodos , Neoplasias Retais/cirurgia , Procedimentos Cirúrgicos Robóticos/métodos , Técnicas Estereotáxicas , Cirurgia Assistida por Computador/métodos , Adulto , Idoso , Estudos de Viabilidade , Feminino , Humanos , Masculino , Ilustração Médica , Projetos Piloto
14.
J Biol Chem ; 293(49): 19047-19063, 2018 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-30327429

RESUMO

Homogalacturonan (HG) is a pectic glycan in the plant cell wall that contributes to plant growth and development and cell wall structure and function, and interacts with other glycans and proteoglycans in the wall. HG is synthesized by the galacturonosyltransferase (GAUT) gene family. Two members of this family, GAUT1 and GAUT7, form a heteromeric enzyme complex in Arabidopsis thaliana Here, we established a heterologous GAUT expression system in HEK293 cells and show that co-expression of recombinant GAUT1 with GAUT7 results in the production of a soluble GAUT1:GAUT7 complex that catalyzes elongation of HG products in vitro The reaction rates, progress curves, and product distributions exhibited major differences dependent upon small changes in the degree of polymerization (DP) of the oligosaccharide acceptor. GAUT1:GAUT7 displayed >45-fold increased catalytic efficiency with DP11 acceptors relative to DP7 acceptors. Although GAUT1:GAUT7 synthesized high-molecular-weight polymeric HG (>100 kDa) in a substrate concentration-dependent manner typical of distributive (nonprocessive) glycosyltransferases with DP11 acceptors, reactions primed with short-chain acceptors resulted in a bimodal product distribution of glycan products that has previously been reported as evidence for a processive model of GT elongation. As an alternative to the processive glycosyltransfer model, a two-phase distributive elongation model is proposed in which a slow phase, which includes the de novo initiation of HG and elongation of short-chain acceptors, is distinguished from a phase of rapid elongation of intermediate- and long-chain acceptors. Upon reaching a critical chain length of DP11, GAUT1:GAUT7 elongates HG to high-molecular-weight products.


Assuntos
Proteínas de Arabidopsis/metabolismo , Glucuronosiltransferase/metabolismo , Pectinas/biossíntese , Arabidopsis/enzimologia , Proteínas de Arabidopsis/química , Glucuronosiltransferase/química , Células HEK293 , Humanos , Modelos Biológicos , Estrutura Molecular , Pectinas/química , Eletricidade Estática , Especificidade por Substrato , Açúcares de Uridina Difosfato/metabolismo
15.
Surg Endosc ; 32(8): 3582-3591, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29435745

RESUMO

BACKGROUND: Long-term morbidity after multimodal treatment for rectal cancer is suggested to be mainly made up by nerve-injury-related dysfunctions. Stereotactic navigation for rectal surgery was shown to be feasible and will be facilitated by highlighting structures at risk of iatrogenic damage. The aim of this study was to investigate the ability to make a 3D map of the pelvic nerves with magnetic resonance imaging (MRI). METHODS: A systematic review was performed to identify a main positional reference for each pelvic nerve and plexus. The nerves were manually delineated in 20 volunteers who were scanned with a 3-T MRI. The nerve identifiability rate and the likelihood of nerve identification correctness were determined. RESULTS: The analysis included 61 studies on pelvic nerve anatomy. A main positional reference was defined for each nerve. On MRI, the sacral nerves, the lumbosacral plexus, and the obturator nerve could be identified bilaterally in all volunteers. The sympathetic trunk could be identified in 19 of 20 volunteers bilaterally (95%). The superior hypogastric plexus, the hypogastric nerve, and the inferior hypogastric plexus could be identified bilaterally in 14 (70%), 16 (80%), and 14 (70%) of the 20 volunteers, respectively. The pudendal nerve could be identified in 17 (85%) volunteers on the right side and in 13 (65%) volunteers on the left side. The levator ani nerve could be identified in only a few volunteers. Except for the levator ani nerve, the radiologist and the anatomist agreed that the delineated nerve depicted the correct nerve in 100% of the cases. CONCLUSION: Pelvic nerves at risk of injury are usually visible on high-resolution MRI with dedicated scanning protocols. A specific knowledge of their course and its application in stereotactic navigation is suggested to improve quality of life by decreasing the likelihood of nerve injury.


Assuntos
Procedimentos Cirúrgicos do Sistema Digestório/métodos , Plexo Hipogástrico/diagnóstico por imagem , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Diafragma da Pelve/cirurgia , Neoplasias Retais/cirurgia , Cirurgia Assistida por Computador/métodos , Humanos , Diafragma da Pelve/diagnóstico por imagem , Diafragma da Pelve/inervação , Neoplasias Retais/diagnóstico
16.
Nat Biotechnol ; 36(3): 249-257, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29431741

RESUMO

Cell walls in crops and trees have been engineered for production of biofuels and commodity chemicals, but engineered varieties often fail multi-year field trials and are not commercialized. We engineered reduced expression of a pectin biosynthesis gene (Galacturonosyltransferase 4, GAUT4) in switchgrass and poplar, and find that this improves biomass yields and sugar release from biomass processing. Both traits were maintained in a 3-year field trial of GAUT4-knockdown switchgrass, with up to sevenfold increased saccharification and ethanol production and sixfold increased biomass yield compared with control plants. We show that GAUT4 is an α-1,4-galacturonosyltransferase that synthesizes homogalacturonan (HG). Downregulation of GAUT4 reduces HG and rhamnogalacturonan II (RGII), reduces wall calcium and boron, and increases extractability of cell wall sugars. Decreased recalcitrance in biomass processing and increased growth are likely due to reduced HG and RGII cross-linking in the cell wall.


Assuntos
Biocombustíveis , Parede Celular/genética , Glucuronosiltransferase/genética , Pectinas/biossíntese , Biomassa , Boro/metabolismo , Cálcio/metabolismo , Parede Celular/enzimologia , Parede Celular/metabolismo , Produtos Agrícolas , Glucuronosiltransferase/química , Panicum/enzimologia , Panicum/genética , Pectinas/genética , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/genética , Populus/enzimologia , Populus/genética , Açúcares/metabolismo
17.
Biotechnol Biofuels ; 11: 9, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29371885

RESUMO

BACKGROUND: The development of fast-growing hardwood trees as a source of lignocellulosic biomass for biofuel and biomaterial production requires a thorough understanding of the plant cell wall structure and function that underlie the inherent recalcitrance properties of woody biomass. Downregulation of GAUT12.1 in Populus deltoides was recently reported to result in improved biomass saccharification, plant growth, and biomass yield. To further understand GAUT12.1 function in biomass recalcitrance and plant growth, here we report the effects of P. trichocarpa GAUT12.1 overexpression in P. deltoides. RESULTS: Increasing GAUT12.1 transcript expression by 7-49% in P. deltoides PtGAUT12.1-overexpression (OE) lines resulted in a nearly complete opposite biomass saccharification and plant growth phenotype to that observed previously in PdGAUT12.1-knockdown (KD) lines. This included significantly reduced glucose, xylose, and total sugar release (12-13%), plant height (6-54%), stem diameter (8-40%), and overall total aerial biomass yield (48-61%) in 3-month-old, greenhouse-grown PtGAUT12.1-OE lines compared to controls. Total lignin content was unaffected by the gene overexpression. Importantly, selected PtGAUT12.1-OE lines retained the recalcitrance and growth phenotypes upon growth for 9 months in the greenhouse and 2.8 years in the field. PtGAUT12.1-OE plants had significantly smaller leaves with lower relative water content, and significantly reduced stem wood xylem cell numbers and size. At the cell wall level, xylose and galacturonic acid contents increased markedly in total cell walls as well as in soluble and insoluble cell wall extracts, consistent with increased amounts of xylan and homogalacturonan in the PtGAUT12.1-OE lines. This led to increased cell wall recalcitrance, as manifested by the 9-15% reduced amounts of recovered extractable wall materials and 8-15% greater amounts of final insoluble pellet in the PtGAUT12.1-OE lines compared to controls. CONCLUSIONS: The combined phenotype and chemotype data from P. deltoides PtGAUT12.1-OE and PdGAUT12.1-KD transgenics clearly establish GAUT12.1 as a recalcitrance- and growth-associated gene in poplar. Overall, the data support the hypothesis that GAUT12.1 synthesizes either an HG-containing primer for xylan synthesis or an HG glycan required for proper xylan deposition, anchoring, and/or architecture in the wall, and the possibility of HG and xylan glycans being connected to each other by a base-sensitive covalent linkage.

18.
Surg Endosc ; 32(6): 2713-2720, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29214516

RESUMO

BACKGROUND: Stereotactic navigation could improve the quality of surgery for rectal cancer. Critical challenges related to soft tissue stereotactic pelvic navigation include the potential difference in patient anatomy between intraoperative lithotomy and preoperative supine position for imaging. The objective of this study was to determine the difference in patient anatomy, sacral tilt, and skin fiducial position between these different patient positions and to investigate the feasibility and optimal set-up for stereotactic pelvic navigation. METHODS: Four consecutive human anatomical specimens were submitted to repeated CT-scans in a supine and several degrees of lithotomy position. Patient anatomy, sacral tilt, and skin fiducial position were compared by means of an image computing platform. In two specimens, a 10-degree wedge was introduced to reduce the natural tilt of the sacrum during the shift from supine to lithotomy position. A simulation of laparoscopic and transanal surgical procedures was performed to assess the accuracy of the stereotactic navigation. RESULTS: An up-to-supracentimetric change in patient anatomy was noted between different patient positions. This observation was minimized through the application of a wedge. When switching from supine to another position, sacral retroversion occurred independent of the use of a wedge. There was considerable skin fiducial motion between different positions. Accurate stereotactic navigation was obtained with the least registration error (1.9 mm) when the position of the anatomical specimen was registered in a supine position with straight legs, without pneumoperitoneum, using a conventional CT-scan with an identical specimen positioning. CONCLUSION: The change in patient anatomy is small during the sacral tilt induced by positional changes when using a 10-degree wedge, allowing for an accurate stereotactic surgical navigation. This opens up new promising opportunities to increase the quality of surgery for rectal cancer cases where it is difficult or impossible to identify and dissect along the anatomical planes.


Assuntos
Imageamento Tridimensional , Laparoscopia/métodos , Pelve/cirurgia , Neoplasias Retais/cirurgia , Cirurgia Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Cadáver , Humanos , Masculino , Pelve/diagnóstico por imagem , Postura , Neoplasias Retais/diagnóstico
20.
Langmuir ; 33(36): 9106-9114, 2017 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-28793185

RESUMO

Multifunctional surfaces with reversible wetting characteristics are fabricated utilizing end-anchored polymer chains on hierarchically roughened surfaces. Temperature- and/or pH-responsive surfaces are developed that exhibit reversible and controllable wettability, from the "parahydrophobic" behavior of natural plant leaves all the way to superhydrophilic properties in response to the external stimuli. For this purpose, dual scale micro/nanoroughened surfaces were prepared by laser irradiation of inorganic surfaces (Si wafers) utilizing ultrafast (femtosecond) laser pulses under a reactive gas atmosphere. End-functionalized polymer chains were anchored onto those surfaces utilizing the "grafting to" method; poly(N-isopropylacrylamide), PNIPAM, and poly(2-vinylpyridine), P2VP, were used for the formation of monofunctional as well as mixed brushes. The surfaces exhibit "parahydrophobic" behavior in the hydrophobic state (high temperature and/or high pH), with high static contact angles (∼120°) and high water adhesion (∼30° contact angle hysteresis), whereas they show superhydrophilic behavior in the hydrophilic state (low temperature and/or low pH). The surfaces were tested for their wettability under repetitive cycles and found to be stable and reproducible.

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