► Cellulose whiskers can be isolated from rice husk and show good aspect ratio. ► Cellulose can be extracted from rice husk by a chlorine free multistep procedure. ► Cellulose thermally decomposes by ...depolymerisation and by release of gas products. ► Cellulose obtained from rice husk shows high crystallinity.
This work reports the isolation of cellulose whiskers from rice husk (RH) by means of an environmental friendly process for cellulose extraction and bleaching. The multistep process begins with the removal of pectin, cutin, waxes and other extractives from rice husk, then an alkaline treatment for the removal of hemicelluloses and lignin, and a two-step bleaching with hydrogen peroxide/tetra-acetylethylenediamine (TAED), followed by a mixture of acetic and nitric acids, for further delignification of the cellulose pulp. The techniques of infrared absorption spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), modulated differential scanning calorimetry (MDSC) and X-ray diffraction (XRD) showed that the overall process is adequate to obtain cellulose with high purity and crystallinity. This cellulose was submitted to sulfuric acid hydrolysis with the aim to isolate the whiskers. They showed the typical elongated rod-like aspect as revealed by transmission electron microscopy (TEM) and atomic force microscopy (AFM).
In this work cellulose was extracted from corn/maize straw (Zea mays) by means of an environmental-friendly multistep procedure involving alkaline treatment and a totally chlorine-free bleaching. ...This multistep procedure efficiently removed lignin and hemicelluloses. The pulp resulting from each step was characterized by attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR). The optimum pulping time (time of alkaline treatment) was determined by means of thermogravimetric analysis. The extracted cellulose is highly crystalline as verified by X-ray diffraction. The partial acid hydrolysis with sulfuric acid led to the isolation of cellulose whiskers in aqueous suspension as confirmed by light scattering and transmission electron microscopy. The depolarization ratio value of these nanocrystals is the same as that determined for cotton whiskers, showing that this ratio does not depend on the cellulose source. The maize whiskers are arranged laterally in bundles with average thickness around five times that of the crystallite.
A dynamic light scattering (DLS) study was performed to investigate the interactions of maize straw cellulose nanocrystals (CNC) with the cationic surfactant hexadecyltrimethylammonium bromide ...(CTAB). Phase analysis light scattering (which gives access to zeta potential (
ζ
) and electrical conductance) technique was used with the aim to obtain additional information. Zeta potential behavior demonstrated the colloidal systems are stable. By electrical conductance data, it was verified that the process of formation of micelles is thermodynamically spontaneous. Dynamic light scattering was shown to be very useful to find the optimum hydrolysis time so as to obtain well dispersed and more isolated nanocrystals. In the presence of the cationic surfactant CTAB, the formation of micelles and aggregates CNC/CTAB were well identified by DLS showing that the dynamics of cellulose nanocrystals in aqueous suspensions is strongly affected by the surfactant.
Hydroxypropylcellulose（HPC） films were prepared by casting with cellulose nanocrystals in the presence of anionic surfactant sodium dodecylsulphate（SDS） and cationic surfactant hexadecyltrimethyl ...ammonium bromide（CTAB）. The cellulose nanocrystals were isolated from maize straw, a biomass source produced in huge quantities as an agrowaste in Brazil. These bionanocomposite films had good transparency and their surface hydrophilic character was evidenced by static contact angle measurements. Thermogravimetry（TGA） measurement revealed that nanocrystals and surfactants changed the thermal stability of the HPC films. Dynamic mechanical analysis（DMA） showed that the tensile storage and loss moduli of the HPC films increased by increasing the contents of cellulose nanocrystals and surfactants, especially in the case of CTAB. This good reinforcing effect of HPC matrix can be explained as due to electrostatic attractive interactions brought about by the presence of CTAB and the nanocrystals.
Summary Background Most data for treatment of dermatomyositis and juvenile dermatomyositis are from anecdotal, non-randomised case series. We aimed to compare, in a randomised trial, the efficacy and ...safety of prednisone alone with that of prednisone plus either methotrexate or ciclosporin in children with new-onset juvenile dermatomyositis. Methods We did a randomised trial at 54 centres in 22 countries. We enrolled patients aged 18 years or younger with new-onset juvenile dermatomyositis who had received no previous treatment and did not have cutaneous or gastrointestinal ulceration. We randomly allocated 139 patients via a computer-based system to prednisone alone or in combination with either ciclosporin or methotrexate. We did not mask patients or investigators to treatment assignments. Our primary outcomes were the proportion of patients achieving a juvenile dermatomyositis PRINTO 20 level of improvement (20% improvement in three of six core set variables at 6 months), time to clinical remission, and time to treatment failure. We compared the three treatment groups with the Kruskal-Wallis test and Friedman's test, and we analysed survival with Kaplan-Meier curves and the log-rank test. Analysis was by intention to treat. Here, we present results after at least 2 years of treatment (induction and maintenance phases). This trial is registered with ClinicalTrials.gov , number NCT00323960. Findings Between May 31, 2006, and Nov 12, 2010, 47 patients were randomly assigned prednisone alone, 46 were allocated prednisone plus ciclosporin, and 46 were randomised prednisone plus methotrexate. Median duration of follow-up was 35·5 months. At month 6, 24 (51%) of 47 patients assigned prednisone, 32 (70%) of 46 allocated prednisone plus ciclosporin, and 33 (72%) of 46 administered prednisone plus methotrexate achieved a juvenile dermatomyositis PRINTO 20 improvement (p=0·0228). Median time to clinical remission was 41·9 months in patients assigned prednisone plus methotrexate but was not observable in the other two treatment groups (2·45 fold 95% CI 1·2–5·0 increase with prednisone plus methotrexate; p=0·012). Median time to treatment failure was 16·7 months in patients allocated prednisone, 53·3 months in those assigned prednisone plus ciclosporin, but was not observable in patients randomised to prednisone plus methotrexate (1·95 fold 95% CI 1·20–3·15 increase with prednisone; p=0·009). Median time to prednisone discontinuation was 35·8 months with prednisone alone compared with 29·4–29·7 months in the combination groups (p=0·002). A significantly greater proportion of patients assigned prednisone plus ciclosporin had adverse events, affecting the skin and subcutaneous tissues, gastrointestinal system, and general disorders. Infections and infestations were significantly increased in patients assigned prednisone plus ciclosporin and prednisone plus methotrexate. No patients died during the study. Interpretation Combined treatment with prednisone and either ciclosporin or methotrexate was more effective than prednisone alone. The safety profile and steroid-sparing effect favoured the combination of prednisone plus methotrexate. Funding Italian Agency of Drug Evaluation, Istituto Giannina Gaslini (Genoa, Italy), Myositis Association (USA).
Juvenile-Takayasu arteritis (j-TA) is a difficult diagnosis and some patients develop uncommon manifestations and associated diseases that may contribute to the delayed diagnosis. Our aim was to ...identify the misdiagnoses, the associated diseases and the atypical manifestations observed in a j-TA Brazilian multicentre study. 71 children and adolescents who met the classification criteria for j-TA were included. The misdiagnoses, the associated diseases and the atypical manifestations were evaluated. 19 (26.8%) patients had misdiagnoses. The most common of them was aortic coarctation in six (8.4%) patients, followed by rheumatic fever in five (7.0%) and one patient presented with both former diagnoses. Limb pain (two patients), spondyloarthropathy, juvenile idiopathic arthritis (JIA), spinal arteriovenous malformation, polyarteritis nodosa (PAN) and fever of unknown origin (FUO) were other misdiagnoses. Patients who had misdiagnoses previously to j-TA diagnosis presented a trend to have a longer diagnosis delay. 11 (15.5%) patients had 14 TA-associated diseases, such as pulmonary tuberculosis (5 patients), rheumatic fever (2 patients), spondyloarthropathy, polyarticular JIA, Crohn’s disease, Prader–Willi disease, diabetes mellitus, Moyamoya and primary immunodeficiency. 7 (9.9%) patients presented 10 atypical manifestations, such as pyoderma gangrenosum, erythema nodosum, myositis, chorea, enthesitis, episcleritis, uveitis, hepatomegaly, splenomegaly and necrosis of extremities. Our study emphasizes the main misdiagnoses, associated diseases and atypical manifestations that occur in patients with j-TA and warns of the features that may alert paediatricians to this diagnosis, such as constitutional symptoms and elevated inflammatory markers.
To assess childhood-onset systemic lupus erythematosus-related antiphospholipid syndrome(cSLE-APS) in a large Brazilian population.
A retrospective observational cohort study was carried-out in 27 ...Pediatric Rheumatology university centers, including 1519 cSLE patients.
cSLE-APS was observed in 67/1519 (4%) and was diagnosed at disease onset in 39/67 (58%). The median disease duration was 4.9 (0–17) years. Thrombosis recurrences were evidenced in 18/67 (27%) cSLE-APS patients. The most frequent thrombosis sites in cSLE-APS patients were: venous thrombosis in 40/67 (60%), especially deep vein thrombosis in 29/40 (72%); arterial thrombosis in 35/67 (52%), particularly stroke; small vessels thrombosis in 9/67 (13%) and mixed thrombosis in 3/67 (4%). Pregnancy morbidity was observed in 1/67 (1%). Non-thrombotic manifestation associated to cSLE-APS occurred in 21/67 (31%), mainly livedo reticularis in 14/67 (21%), valvar thickening in 4/67 (6%) and valvar vegetations not related to infections in 2/67 (3%). None of them had catastrophic APS. Further analysis demonstrated that the median of SLICC/ACR-DI 1(0–5) vs. 0(0–7),p < 0.0001 was significantly higher in cSLE-APS patients compared to cSLE without APS. The frequencies of cerebrovascular disease (40% vs. 1%,p < 0.0001), polyneuropathy (9% vs. 1%,p < 0.0001), SLICC/ACR-DI ≥1 (57% vs. 27%, p < 0.0001) and intravenous cyclophosphamide use (59% vs. 37%, p < 0.0001) were significantly higher in the former group.
Our large multicenter study demonstrated that cSLE-APS was a rare condition, occurring during disease course with a high accrual damage. Central and peripheral neuropsychiatric involvements were distinctive features of this autoimmune thrombosis.
•Our large multicenter study demonstrated that cSLE-APS was a rare complication. APS occurs early at c-SLE course with a high accrual damage. Central and peripheral neuropsychiatric involvements were distinctive features of this autoimmune thrombosis.
Background
Lupus nephritis (LN) is a frequent manifestation of childhood-onset systemic lupus erythematosus (cSLE) with a potential risk for kidney failure and poor outcomes. This study aimed to ...evaluate stages III, IV, and V of chronic kidney disease (CKD) and investigate risk factors for CKD in cSLE patients.
Methods
We performed a nationwide observational cohort study in 27 pediatric rheumatology centers, including medical charts of 1528 cSLE patients. Data were collected at cSLE diagnosis, during follow-up, and at last visit or death, between September 2016 and May 2019.
Results
Of 1077 patients with LN, 59 (5.4%) presented with CKD, 36/59 (61%) needed dialysis, and 7/59 (11.8%) were submitted for kidney transplantation. After Bonferroni’s correction for multiple comparisons (
p <
0.0013), determinants associated with CKD were higher age at last visit, urinary biomarker abnormalities, neuropsychiatric involvement, higher scores of disease activity at last visit and damage index, and more frequent use of methylprednisolone, cyclosporine, cyclophosphamide, and rituximab. In the regression model analysis, arterial hypertension (HR = 15.42, 95% CI = 6.12–38.83,
p
≤ 0.001) and biopsy-proven proliferative nephritis (HR = 2.83, 95%CI = 1.70–4.72,
p
≤ 0.001) increased the risk of CKD, while children using antimalarials had 71.0% lower CKD risk ((1.00–0.29) × 100%) than children not using them. The Kaplan–Meier comparison showed lower survival in cSLE patients with biopsy-proven proliferative nephritis (
p
= 0.02) and CKD (
p
≤ 0.001).
Conclusions
A small number of patients manifested CKD; however, frequencies of dialysis and kidney transplantation were relevant. This study reveals that patients with cSLE with hypertension, proliferative nephritis, and absence of use of antimalarials exhibited higher hazard rates of progression to CKD.
Graphical Abstract
A higher resolution version of the Graphical abstract is available as
Supplementary information
Objectives
To identify associations between mortality in cSLE patients and their characteristics: clinical and laboratory features, disease activity and damage scores, and treatment; to evaluate risk ...factors associated with mortality in cSLE; and to determine the most frequent causes of death in this group of patients.
Methods
We performed a multicenter retrospective cohort using data from 1,528 cSLE patients followed in 27 pediatric rheumatology tertiary centers in Brazil. Patients’ medical records were reviewed according to a standardized protocol, in which information regarding demographic and clinical features, disease activity and damage scores, and treatment were collected and compared between deceased cSLE patients and survivors. Univariate and multivariate analyses by Cox regression model were used to calculate risk factors for mortality, whereas survival rates were analyzed by Kaplan–Meier plots.
Results
A total of 63/1,528 (4.1%) patients deceased, 53/63 were female (84.1%), median age at death was 11.9 (9.4–13.1) years and median time interval between cSLE diagnosis and death was 3.2 (0.5–5.3) years. Sepsis was the main cause of death in 27/63 (42.8%) patients, followed by opportunistic infections in 7/63 (11.1%), and alveolar hemorrhage in 6/63 (9.5%) patients. The regression models resulted in neuropsychiatric lupus (NP-SLE) (HR = 2.56, 95% CI = 1.48–4.42) and chronic kidney disease (CKD) (HR = 4.33, 95% CI = 2.33–4.72), as risk factors significantly associated with mortality. Overall patient survival after cSLE diagnosis at 5, 10, and 15 years were 97%, 95.4%, and 93.8%, respectively.
Conclusions
This study confirmed that the recent mortality rate in cSLE in Brazil is low, but still of concern. NP-SLE and CKD were the main risk factors for mortality, indicating that the magnitude of these manifestations was significantly high.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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