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1.
BMC Infect Dis ; 23(1): 650, 2023 Oct 03.
Article in English | MEDLINE | ID: mdl-37789266

ABSTRACT

BACKGROUND: Calprotectin is an inflammatory marker mainly released by activated neutrophils that is increased in acute severe COVID-19. After initial recovery, some patients have persistent respiratory impairment with reduced diffusion capacity of the lungs for carbon monoxide (DLCO) months after infection. Underlying causes of this persistent impairment are unclear. We aimed to investigate the correlation between circulating calprotectin, persistent lung functional impairment and intensive care unit (ICU) stay after COVID-19 in two university hospital centres in Switzerland. METHODS: Calprotectin levels were measured in serum from 124 patients (50% male) from the Bern cohort (post-ICU and non-ICU patients) and 68 (76% male) from the Lausanne cohort (only post-ICU patients) four months after COVID-19. Calprotectin was correlated with clinical parameters. Multivariate linear regression (MLR) was performed to evaluate the independent association of calprotectin in different models. RESULTS: Overall, we found that post-ICU patients, compared to non-ICU, were significantly older (age 59.4 ± 13.6 (Bern), 60.5 ± 12.0 (Lausanne) vs. 48.8 ± 13.4 years) and more obese (BMI 28.6 ± 4.5 and 29.1 ± 5.3 vs. 25.2 ± 6.0 kg/m2, respectively). 48% of patients from Lausanne and 44% of the post-ICU Bern cohort had arterial hypertension as a pre-existing comorbidity vs. only 10% in non-ICU patients. Four months after COVID-19 infection, DLCO was lower in post-ICU patients (75.96 ± 19.05% predicted Bern, 71.11 ± 18.50% Lausanne) compared to non-ICU (97.79 ± 21.70% predicted, p < 0.01). The post-ICU cohort in Lausanne had similar calprotectin levels when compared to the cohort in Bern (Bern 2.74 ± 1.15 µg/ml, Lausanne 2.49 ± 1.13 µg/ml vs. non-ICU 1.86 ± 1.02 µg/ml; p-value < 0.01). Calprotectin correlated negatively with DLCO (r= -0.290, p < 0.001) and the forced vital capacity (FVC) (r= -0.311, p < 0.001). CONCLUSIONS: Serum calprotectin is elevated in post-ICU patients in two independent cohorts and higher compared to non-ICU patients four months after COVID-19. In addition, there is a negative correlation between calprotectin levels and DLCO or FVC. The relationship between inflammation and lung functional impairment needs further investigations. TRIAL REGISTRATION: NCT04581135.


Subject(s)
COVID-19 , Hypertension , Aged , Female , Humans , Male , Middle Aged , Critical Care , Hospitals, University , Leukocyte L1 Antigen Complex , Lung
2.
Clin Oncol (R Coll Radiol) ; 35(6): e362-e375, 2023 06.
Article in English | MEDLINE | ID: mdl-36967312

ABSTRACT

AIMS: Understanding the correlations between underlying medical and personal characteristics of a patient with cancer and the risk of lung metastasis may improve clinical management and outcomes. We used machine learning methodologies to predict the risk of lung metastasis using readily available predictors. MATERIALS AND METHODS: We retrospectively analysed a cohort of 11 164 oncological patients, with clinical records gathered between 2000 and 2020. The input data consisted of 94 parameters, including age, body mass index (BMI), sex, social history, 81 primary cancer types, underlying lung disease and diabetes mellitus. The strongest underlying predictors were discovered with the analysis of the highest performing method among four distinct machine learning methods. RESULTS: Lung metastasis was present in 958 of 11 164 oncological patients. The median age and BMI of the study population were 63 (±19) and 25.12 (±5.66), respectively. The random forest method had the most robust performance among the machine learning methods. Feature importance analysis revealed high BMI as the strongest predictor. Advanced age, smoking, male gender, alcohol dependence, chronic obstructive pulmonary disease and diabetes were also strongly associated with lung metastasis. Among primary cancers, melanoma and renal cancer had the strongest correlation. CONCLUSIONS: Using a machine learning-based approach, we revealed new correlations between personal and medical characteristics of patients with cancer and lung metastasis. This study highlights the previously unknown impact of predictors such as obesity, advanced age and underlying lung disease on the occurrence of lung metastasis. This prediction model can assist physicians with preventive risk factor control and treatment strategies.


Subject(s)
Diabetes Mellitus , Lung Neoplasms , Humans , Male , Retrospective Studies , Risk Factors , Diabetes Mellitus/epidemiology
3.
Biomater Sci ; 11(6): 2033-2045, 2023 Mar 14.
Article in English | MEDLINE | ID: mdl-36752615

ABSTRACT

Dynamic hydrogels are viscoelastic materials that can be designed to be self-healing, malleable, and injectable, making them particularly interesting for a variety of biomedical applications. To design dynamic hydrogels, dynamic covalent crosslinking reactions are attracting increasing attention. However, dynamic covalent hydrogels tend to swell, and often lack stability. Boronate ester-based hydrogels, which result from the dynamic covalent reaction between a phenylboronic acid (PBA) derivative and a diol, are based on stable precursors, and can therefore address these limitations. Yet, boronate ester formation hardly occurs at physiological pH. To produce dynamic covalent hydrogels at physiological pH, we performed a molecular screening of PBA derivatives in association with a variety of diols, using hyaluronic acid as a polymer of interest. The combination of Wulff-type PBA (wPBA) and glucamine stood out as a unique couple to obtain the desired hydrogels. We showed that optimized wPBA/glucamine hydrogels are minimally- to non-swelling, stable long term (over months), tunable in terms of mechanical properties, and cytocompatible. We further characterized their viscoelastic and self-healing properties, highlighting their potential for biomedical applications.


Subject(s)
Esters , Hydrogels , Hydrogels/chemistry , Polymers/chemistry , Boronic Acids/chemistry
4.
Cancer Radiother ; 27(1): 31-41, 2023 Feb.
Article in English | MEDLINE | ID: mdl-35965243

ABSTRACT

PURPOSE: To compare three different radiotherapy devices able to perform pulmonary stereotactic radiotherapy: CyberKnife® (CK), Helical Tomotherapy® (HT), and volumetric modulated arc therapy (VMAT). This study aims to define the patients' outcome in terms of SBRT efficacy and toxicities depending of the device choice. MATERIALS AND METHODS: We retrospectively analyzed the clinical, radiological, and dosimetric data of patients treated with lung SBRT between 2016 and 2020 at Lausanne University Hospital, using the Chi2 test for proportions, the t-test for means comparisons, the Kaplan-Meier method for survival, and the Log-rank test and Cox-regression for intergroups comparisons. RESULTS: We identified 111 patients treated by either CK (59.9%), VMAT (38.0%), or HT (2.1%). Compared to other techniques, CK treated comparable gross tumor volume (GTV; 2.1 vs. 1.4cm3, P=0.84) with smaller planning treatment volume (PTV; 12.3 vs. 21.9cm3, P=0.013) and lower V5 (13.5 vs. 19.9cm3, P=0.002). Local control rates at 2years were not different whatever the irradiation device, respectively of 96.2% (range, 90.8-100) and 98.1% (range, 94.4-100), P=0.68. Toxicity incidence significantly increased with V5 value>17.2% (56.0 vs. 77.4%, P=0.021). CONCLUSION: Compared to other SBRT techniques, CK treatments permitted to treat comparable GTV with reduced PTV and V5. Toxicity incidence was less frequent when reducing the V5. CK is particularly attractive in case of multiple courses of lung SBRT or lung reirradiation.


Subject(s)
Lung Neoplasms , Radiosurgery , Radiotherapy, Intensity-Modulated , Humans , Radiosurgery/adverse effects , Radiosurgery/methods , Retrospective Studies , Lung Neoplasms/pathology , Radiotherapy, Intensity-Modulated/adverse effects , Radiotherapy, Intensity-Modulated/methods , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy Dosage , Lung
5.
Arch Pediatr ; 29(8): 581-587, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36109288

ABSTRACT

INTRODUCTION: Pediatric chronic pain can lead to serious consequences in terms of daily functioning and global quality of life. Mindfulness-based intervention (MBI) approaches that emphasize accepting rather than controlling pain have gained increasing attention in adults with chronic pain. The effectiveness of MBIs for chronic pain in the pediatric population remains unknown. The aim of the Peacefull program was to study the feasibility in France of a mindfulness program for adolescents with chronic pain, based on a program especially developed in Canada and Belgium. METHOD: An MBI for adolescents consisting of eight 90-min sessions was provided. It focused on building skills and incorporated mindfulness meditation, exercises, and activities especially adapted to teenagers with chronic pain. RESULTS: A total of 27 adolescents aged 12-17 years who were diagnosed with a chronic pain condition were enrolled in five cohorts from April 2018 to June 2021. The completion rate of the Peacefull program was 88.89 with no dropouts and good completion of outcome measures. Secondary outcomes were assessed before the program, at the end, and 3 months later. A trend toward an improvement was observed on the mean average score for the Visual Analog Scale (VAS), but it was not statistically significant. Scores increased significantly over time on the Functional Disability Inventory (FDI), and pain catastrophizing also improved. CONCLUSIONS: Although the findings regarding the effectiveness of Peacefull programs were inconsistent and insufficient, they can be indicative of the benefits of mindfulness as an adjuvant treatment for adolescents with chronic pain.


Subject(s)
Chronic Pain , Mindfulness , Adult , Adolescent , Child , Humans , Chronic Pain/therapy , Feasibility Studies , Quality of Life , Treatment Outcome , Chronic Disease
6.
Arch Pediatr ; 29(4): 312-325, 2022 May.
Article in English | MEDLINE | ID: mdl-35305879

ABSTRACT

OBJECTIVES: Nutritional vitamin D supplements are often used in general pediatrics. Here, the aim is to address vitamin D supplementation and calcium nutritional intakes in newborns, infants, children, and adolescents to prevent vitamin D deficiency and rickets in general populations. STUDY DESIGN: We formulated clinical questions relating to the following categories: the Patient (or Population) to whom the recommendation will apply; the Intervention being considered; the Comparison (which may be "no action," placebo, or an alternative intervention); and the Outcomes affected by the intervention (PICO). These PICO elements were arranged into the questions to be addressed in the literature searches. Each PICO question then formed the basis for a statement. The population covered consisted of children aged between 0 and 18 years and premature babies hospitalized in neonatology. Two groups were assembled: a core working group and a voting panel from different scientific pediatric committees from the French Society of Pediatrics and national scientific societies. RESULTS: We present here 35 clinical practice points (CPPs) for the use of native vitamin D therapy (ergocalciferol, vitamin D2 and cholecalciferol, vitamin D3) and calcium nutritional intakes in general pediatric populations. CONCLUSION: This consensus document was developed to provide guidance to health care professionals on the use of nutritional vitamin D and dietary modalities to achieve the recommended calcium intakes in general pediatric populations. These CPPs will be revised periodically. Research recommendations to study key vitamin D outcome measures in children are also suggested.


Subject(s)
Neonatology , Vitamin D Deficiency , Adolescent , Calcium , Calcium, Dietary , Child , Child, Preschool , Cholecalciferol , Consensus , Dietary Supplements , Humans , Infant , Infant, Newborn , Vitamin D/therapeutic use , Vitamin D Deficiency/epidemiology , Vitamin D Deficiency/prevention & control , Vitamins/therapeutic use
7.
Waste Manag ; 125: 49-57, 2021 Apr 15.
Article in English | MEDLINE | ID: mdl-33676200

ABSTRACT

Opaque PET (Polyethylene terephthalate) was recently introduced as a dairy packaging, mainly for milk bottles. Opaque PET, obtained as PET filled with mineral nanoparticles, allows for a reduction of bottles' thickness, thus a cost reduction for industrials. For this reason, the use of opaque PET is steadily increasing. However, its recyclability is nowadays an issue: although the recycling channels are well established for transparent PET, the presence of opaque PET in the household wastes weakens the existing recycling channels. Besides, many initiatives are launched in Europe to turn wastes into resources, as one key to a more circular economy. One of the biggest challenges is an efficient sorting of the plastic solid wastes since the PET is not miscible with other plastics such as polypropylene (PP) from the bottle caps and polyethylene (PE) from the other milk bottles. In this work, the mechanical properties of uncompatibilized blends of opaque PET (rPET-O) with recycled polypropylene (rPP) have been studied; both are collected from household wastes. The tensile properties and the fatigue life of rPP, monitored by in-situ digital image correlation and in-situ infrared thermography, are increased by the incorporation of rPET-O. rPET-O/rPP blends may be substituted to rPP for similar applications, with no need to sort the caps from the bottles. Thus, as a concept, the incorporation of opaque PET into the PP recycling sector may be a new route to absorb some of the growing amounts of opaque PET.


Subject(s)
Plastics , Polypropylenes , Animals , Europe , Fatigue , Milk , Polyethylene Terephthalates , Recycling
10.
J Thromb Haemost ; 16(11): 2322-2335, 2018 11.
Article in English | MEDLINE | ID: mdl-30207066

ABSTRACT

Essentials Nitric oxide synthesis controls protein disulfide isomerase (PDI) function. Nitric oxide (NO) modulation of PDI controls endothelial thrombogenicity. S-nitrosylated PDI inhibits platelet function and thrombosis. Nitric oxide maintains vascular quiescence in part through inhibition of PDI. SUMMARY: Background Protein disulfide isomerase (PDI) plays an essential role in thrombus formation, and PDI inhibition is being evaluated clinically as a novel anticoagulant strategy. However, little is known about the regulation of PDI in the vasculature. Thiols within the catalytic motif of PDI are essential for its role in thrombosis. These same thiols bind nitric oxide (NO), which is a potent regulator of vessel function. To determine whether regulation of PDI represents a mechanism by which NO controls vascular quiescence, we evaluated the effect of NO on PDI function in endothelial cells and platelets, and thrombus formation in vivo. Aim To assess the effect of S-nitrosylation on the regulation of PDI and other thiol isomerases in the vasculature. Methods and results The role of endogenous NO in PDI activity was evaluated by incubating endothelium with an NO scavenger, which resulted in exposure of free thiols, increased thiol isomerase activity, and enhanced thrombin generation on the cell membrane. Conversely, exposure of endothelium to NO+ carriers or elevation of endogenous NO levels by induction of NO synthesis resulted in S-nitrosylation of PDI and decreased surface thiol reductase activity. S-nitrosylation of platelet PDI inhibited its reductase activity, and S-nitrosylated PDI interfered with platelet aggregation, α-granule release, and thrombin generation on platelets. S-nitrosylated PDI also blocked laser-induced thrombus formation when infused into mice. S-nitrosylated ERp5 and ERp57 were found to have similar inhibitory activity. Conclusions These studies identify NO as a critical regulator of vascular PDI, and show that regulation of PDI function is an important mechanism by which NO maintains vascular quiescence.


Subject(s)
Endothelial Cells/metabolism , Nitric Oxide/metabolism , Protein Disulfide-Isomerases/metabolism , Thrombosis/metabolism , Abdominal Muscles/metabolism , Animals , Blood Platelets/cytology , Blood Platelets/metabolism , Cell Membrane/metabolism , Factor Xa/metabolism , Human Umbilical Vein Endothelial Cells , Humans , Mice , Mice, Inbred C57BL , P-Selectin/metabolism , Platelet Activation , Platelet Aggregation , Recombinant Proteins/metabolism , Sulfhydryl Compounds/metabolism , Thrombin/metabolism
12.
Allergy ; 72(10): 1437-1439, 2017 10.
Article in English | MEDLINE | ID: mdl-28561329
13.
Sci Total Environ ; 592: 535-545, 2017 Aug 15.
Article in English | MEDLINE | ID: mdl-28318697

ABSTRACT

The aim of this study was to compare the efficiency of siderophore desferrioxamine B (DFOB) and EDTA in increasing the phytoextraction of metals in sunflower. A 28-day pot experiment was conducted in a metal-contaminated soil supplied with 200µmolkg-1 of DFOB or EDTA. Pore water was collected and pseudo-polarographic analyses were conducted to assess the impact of the two chelators on the mobility and speciation of metals in the liquid phase. Our results showed that DFOB is not an efficient mobilizing agent of divalent metals in soil. Adding DFOB selectively increased the mobility of trivalent metals while the supply of EDTA simultaneously increased the mobility of both trivalent and divalent metals. EDTA significantly reduced the labile fractions of Cd, Cu, (Pb) and Zn measured in the porewater. The labile concentration of Cd and Zn measured in presence of EDTA was even less than that measured in the control. As expected from the pore water analysis, the addition of DFOB did not affect the phytoextraction of any divalent metals. In contrast, the addition of EDTA enhanced Cu and Ni phytoextraction in sunflower 2.0 to 2.8 fold for Cu and 1.3 to 2.3 fold for Ni, depending on the cultivar. This result supports different hypotheses regarding the forms and the related pathways in which metals are taken up in presence of EDTA. Based on the results obtained for Ni, whose uptake is rate limited by its internalization across the cell membrane, the direct uptake of metal-EDTA complexes via the non-selective apoplastic pathway is hypothesized to contribute the most to the overall uptake of metals in presence of EDTA, even added at "low" concentrations.


Subject(s)
Deferoxamine/pharmacology , Edetic Acid/pharmacology , Helianthus/drug effects , Metals, Heavy/isolation & purification , Soil Pollutants/isolation & purification , Biodegradation, Environmental , Chelating Agents , Helianthus/metabolism
14.
Talanta ; 134: 530-537, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25618704

ABSTRACT

Many studies have been carried out to identify dissolved organic matter-trace metals interactions, as organic matter (OM) was demonstrated to be a governing parameter of metals speciation. Concerning arsenic (As), such OM-As studies are scarce and concluded that, when As binding occurred, it was probably through cationic bridges or, in some cases, directly. Yet, analytical proofs remained complex to obtain. In this work, As binding with Suwanee River Humic Acid (SRHA), as an example of dissolved organic matter, was studied, considering both As(III) and As(V), at various pH and in absence/presence of Na and Ca. Dialysis, fluorescence measurements and PHREEQC modelling were performed to identify and characterize the mechanisms at work for the various performed experiments. It was observed that As(III) binding on SRHA occurred through direct SRHA-As(III) binding and that neither Na nor Ca presence modify this mechanism. As(V) appeared to be also bound by SRHA through direct interaction, but suffered from the competition of Na for the SRHA binding sites. Oppositely, in presence of Ca, the overall As(V)-SRHA binding was significantly enhanced, Ca acting as an efficient cationic bridge through the formation of an SRHA-Ca-As(V) ternary complex. All the obtained data were satisfactorily simulated using a unique set of binding parameters which can therefore be implemented in any speciation code to better address As behaviour in environmental conditions.

15.
Sci Total Environ ; 502: 296-308, 2015 Jan 01.
Article in English | MEDLINE | ID: mdl-25262292

ABSTRACT

An annual-basis study of the impacts of the anthropogenic inputs from Fez urban area on the water geochemistry of the Sebou and Fez Rivers was conducted mostly focusing on base flow conditions, in addition to the sampling of industrial wastewater characteristic of the various pressures in the studied environment. The measured trace metals dissolved/particulate partitioning was compared to the ones predicted using the WHAM-VII chemical speciation code. The Sebou River, upstream from Fez city, showed a weakly polluted status. Contrarily, high levels of major ions, organic carbon and trace metals were encountered in the Fez River and the Sebou River downstream the Fez inputs, due to the discharge of urban and industrial untreated and hugely polluted wastewaters. Trace metals were especially enriched in particles with levels even exceeding those recorded in surface sediments. The first group of elements (Al, Fe, Mn, Ti, U and V) showed strong inter-relationships, impoverishment in Fez particles/sediments and stable partition coefficient (Kd), linked to their lithogenic origin from Sebou watershed erosion. Conversely, most of the studied trace metals/metalloids, originated from anthropogenic sources, underwent significant changes of Kd and behaved non-conservatively in the Sebou/Fez water mixing. Dissolved/particulate partitioning was correctly assessed by WHAM-VII modeling for Cu, Pb and Zn, depicting significant differences in chemical speciation in the Fez River when compared to that in the Sebou River. The results of this study demonstrated that a lack of compliance in environmental regulations certainly explained this poor status.


Subject(s)
Carbon/analysis , Environmental Monitoring , Geologic Sediments/chemistry , Trace Elements/analysis , Water Pollutants, Chemical/analysis , Industrial Waste/analysis , Industrial Waste/statistics & numerical data , Industry , Morocco , Rivers/chemistry
17.
Environ Monit Assess ; 186(5): 2851-65, 2014 May.
Article in English | MEDLINE | ID: mdl-24389842

ABSTRACT

This study aimed at evidencing contaminant inputs from a rapidly growing population and the accompanying anthropogenic activities to river sediments. The Fez metropolitan area and its impacts on the Sebou's sediments (the main Moroccan river) were chosen as a case study. The Fez agglomeration is surrounded by the river Fez, receiving the wastewaters of this developing city and then flowing into the Sebou. The sediment cores from the Fez and Sebou Rivers were extracted and analysed for major elements, butyltins and toxic metals. Normalised enrichment factors and geoaccumulation index were calculated. Toxicity risk was assessed by two sets of sediment quality guideline (SQG) indices. A moderate level of contamination by butyltins was observed, with monobutyltin being the dominant species across all sites and depths. The lowest level of metal pollution was identified in the Sebou's sediments in upstream of Fez city, whilst the Fez' sediments were heavily polluted and exhibited bottom-up accumulation trends, which is a clear signature of recent inputs from the untreated wastewaters of Fez city. Consequently, the sediments of Fez and Sebou at the downstream of the confluence were found to be potentially toxic, according to the SQG levels. This finding is concerned with aquatic organisms, as well as to the riverside population, which is certainly exposed to these pollutants through the daily use of water. This study suggests that although Morocco has adopted environmental regulations aiming at restricting pollutant discharges into the natural ecosystems, such regulations are neither well respected by the main polluters nor efficiently enforced by the authorities.


Subject(s)
Environmental Monitoring , Geologic Sediments/chemistry , Industry/trends , Metals/analysis , Urbanization/trends , Water Pollutants, Chemical/analysis , Morocco , Rivers/chemistry
18.
Respiration ; 87(3): 254-64, 2014.
Article in English | MEDLINE | ID: mdl-24458197

ABSTRACT

The discussion about setting up a program for lung cancer screening was launched with the publication of the results of the National Lung Screening Trial, which suggested reduced mortality in high-risk subjects undergoing CT screening. However, important questions about the benefit-harm balance and the details of a screening program and its cost-effectiveness remain unanswered. A panel of specialists in chest radiology, respiratory medicine, epidemiology, and thoracic surgery representing all Swiss university hospitals prepared this joint statement following several meetings. The panel argues that premature and uncontrolled introduction of a lung cancer screening program may cause substantial harm that may remain undetected without rigorous quality control. This position paper focuses on the requirements of running such a program with the objective of harmonizing efforts across the involved specialties and institutions and defining quality standards. The underlying statement includes information on current evidence for a reduction in mortality with lung cancer screening and the potential epidemiologic implications of such a program in Switzerland. Furthermore, requirements for lung cancer screening centers are defined, and recommendations for both the CT technique and the algorithm for lung nodule assessment are provided. In addition, related issues such as patient management, registry, and funding are addressed. Based on the current state of the knowledge, the panel concludes that lung cancer screening in Switzerland should be undertaken exclusively within a national observational study in order to provide answers to several critical questions before considering broad population-based screening for lung cancer.


Subject(s)
Early Detection of Cancer/standards , Lung Neoplasms/diagnostic imaging , Hospitals, University , Humans , Mass Screening , Practice Guidelines as Topic , Risk Assessment , Switzerland , Tomography, X-Ray Computed
19.
Carbohydr Polym ; 99: 736-47, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24274565

ABSTRACT

The glycoprotein (GP) molecular fraction structure of the gum exudate of Acacia senegal (gum Arabic) isolated from hydrophobic interaction chromatography was investigated using high-performance size exclusion chromatography-multi angle laser light scattering (HPSEC-MALLS), small angle X-ray scattering (SAXS), synchrotron radiation circular dichroism (SRCD) and transmission electron microscopy (TEM) observations. In solution, GP would be a mixture of spheroidal monomers and more anisotropic oligomers as suggested by the two exponent values found in the Rg vs. Mw relationship and TEM observations. The GP conformation probed by SAXS was ascribed to a thin object with a triaxial ellipsoid morphology, certainly attributed to GP oligomers. A 9 nm diameter particle was also identified by SAXS in agreement with the dimensions identified by TEM on single isolated ring-like structures. The GP oligomerization process, as probed by TEM, would be the result of ring-like subunits self-association. This self-association would lead to more linear or, sometimes, cyclised assembly. At the molecular level, GP fraction was found to have secondary structures mainly made of ß-sheets and turns (64%) but also, to a lesser extent, made of polyproline II (PPII) and α-helices (19%). These features were characteristic of hydroxyprolin-rich glycoproteins with arabinosylated and arabinogalactan polysaccharide side chains grafted to the polypeptide backbone. The GP molecular fraction structure from Acacia gum would be an assembly of ring-like glycoproteins modules. These ring-like structures were certainly due to hydroxyproline (Hyp)-arabinogalactan (AG) subunits.


Subject(s)
Galactans/chemistry , Glycoproteins/chemistry , Gum Arabic/chemistry , Hydroxyproline/chemistry , Chromatography, Gel , Glycoproteins/ultrastructure , Hydrophobic and Hydrophilic Interactions , Microscopy, Electron, Transmission , Molecular Weight , Protein Structure, Secondary , Scattering, Small Angle , X-Ray Diffraction
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