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1.
Aggress Behav ; 50(4): e22169, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-39049178

RESUMO

Aggression is one of the public social issues affecting campus harmony and stability, and social exclusion is an important interpersonal contextual factor among many factors affecting aggression. However, studies examining the influence of social exclusion on aggression and its mediating mechanism are not systematic enough. Based on the general aggression model (GAM), we intend to explore the role of hostile attribution bias (HAB) in both trait and state levels of social exclusion, which leads to aggression through a combination of questionnaire and experimental methods. Study 1 surveyed 388 current high school students (Mage = 16.09, SD = 1.01) and found that HAB mediates the relationship between long-term social exclusion (trait level) and aggression tendency. Study 2 experimented with 181 high school students (Mage = 16.95, SD = 1.13) to examine whether short-term social exclusion (state level) after initiating the Cyberball paradigm could still influence aggressive behavior through the mediating role of HAB. Results found that the mediating role of HAB still holds. The findings of the study further enrich the GAM and have important implications for a more targeted approach to aggression prevention and intervention.


Assuntos
Agressão , Hostilidade , Distância Psicológica , Humanos , Agressão/psicologia , Masculino , Feminino , Adolescente , Estudantes/psicologia , Percepção Social , Comportamento do Adolescente/psicologia
2.
Polymers (Basel) ; 16(11)2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38891492

RESUMO

Cellulose detectors, as green sensors, are some of the defensive mechanisms of plants which combat environmental stresses. However, extracted cellulose struggles to fulfil these functionalities due to its rigid physical/chemical properties. In this study, a novel cellulose dual-crosslinked framework (CDCF) is proposed. This comprises a denser temporary physical crosslinking bond (hydrogen bonding) and a looser covalent crosslinking bond (N,N-methylenebisacrylamide), which create deformable spaces between the two crosslinking sites. Abundant pH-sensitive carboxyl groups and ultralight, highly porous structures make CDCF response very sensitive in acid/alkaline vapor environments. Hence, a significant shrinkage of CDCF was observed following exposure to vapors. Moreover, a curcumin-incorporated CDCF exhibited dual shape and color changes when exposed to acid/alkaline vapors, demonstrating great potential for the multi-detection of acid/alkaline vapors.

3.
Open Med (Wars) ; 19(1): 20240957, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38841175

RESUMO

Objective: The aim of this study was to observe the remission of primary membranous nephropathy (PMN) and evaluate the efficacy of tacrolimus (TAC) monotherapy for PMN in comparison with TAC combined with a low-dose glucocorticoid (GC) protocol (TAC + GC). Methods: This was tested in a prospective monocentric observational trial of 70 patients with PMN, of whom 34 received TAC (0.05-0.075 mg/kg/day) or 36 received TAC (0.05-0.075 mg/kg/day) and GC (0.3-0.5 mg/kg/day of prednisone). Results: At 3, 6, 9, and 12 months of treatment, the effective rates in the TAC group and the TAC + GC group were similar (P > 0.05). The urinary protein quantification was reduced in patients under both therapeutic protocols, and the differences in the proteinuria quantification at 3, 6, 9, and 12 months of treatment were not statistically significant between the two groups (P > 0.05). The overall incidence of adverse reactions in the TAC group was lower than that in the TAC + GC group (23.5% < 36.1%), and the difference was statistically significant (P < 0.05). Conclusion: TAC monotherapy for PMN could effectively reduce urinary protein quantification and increase serum albumin levels. Compared with TAC + GC, TAC monotherapy for PMN had no difference in efficacy and fewer incidences of adverse reactions.

4.
Nat Commun ; 15(1): 3780, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38710714

RESUMO

Recombinant adeno-associated viruses (rAAVs) have emerged as promising gene therapy vectors due to their proven efficacy and safety in clinical applications. In non-human primates (NHPs), rAAVs are administered via suprachoroidal injection at a higher dose. However, high doses of rAAVs tend to increase additional safety risks. Here, we present a novel AAV capsid (AAVv128), which exhibits significantly enhanced transduction efficiency for photoreceptors and retinal pigment epithelial (RPE) cells, along with a broader distribution across the layers of retinal tissues in different animal models (mice, rabbits, and NHPs) following intraocular injection. Notably, the suprachoroidal delivery of AAVv128-anti-VEGF vector completely suppresses the Grade IV lesions in a laser-induced choroidal neovascularization (CNV) NHP model for neovascular age-related macular degeneration (nAMD). Furthermore, cryo-EM analysis at 2.1 Å resolution reveals that the critical residues of AAVv128 exhibit a more robust advantage in AAV binding, the nuclear uptake and endosome escaping. Collectively, our findings highlight the potential of AAVv128 as a next generation ocular gene therapy vector, particularly using the suprachoroidal delivery route.


Assuntos
Neovascularização de Coroide , Dependovirus , Terapia Genética , Vetores Genéticos , Epitélio Pigmentado da Retina , Animais , Dependovirus/genética , Vetores Genéticos/genética , Vetores Genéticos/administração & dosagem , Terapia Genética/métodos , Camundongos , Epitélio Pigmentado da Retina/metabolismo , Epitélio Pigmentado da Retina/virologia , Neovascularização de Coroide/terapia , Neovascularização de Coroide/genética , Coelhos , Humanos , Técnicas de Transferência de Genes , Degeneração Macular/terapia , Degeneração Macular/genética , Degeneração Macular/patologia , Modelos Animais de Doenças , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Transdução Genética , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Camundongos Endogâmicos C57BL , Retina/metabolismo , Retina/virologia , Masculino , Células HEK293
5.
World J Clin Cases ; 12(8): 1530-1535, 2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38576803

RESUMO

BACKGROUND: The role of primary-level medical pharmacists in medical institutions in China is limited; therefore, it is necessary to explore the role of pharmacists in the process of drug treatment. CASE SUMMARY: A Chinese pharmacist participated in the complete treatment of a patient with a duodenal ulcer. The rationale for drug treatment was evaluated, and adjustments were made to the antacid and anti-infective regimen, as well as the dose and frequency of administration. Body temperature, routine blood examination, and adverse drug reactions were strictly monitored. During treatment, the pharmacist recommended anti-infective therapy with ampicillin-sulbactam, which effectively controlled the infection. Additionally, the pharmacist suggested changing famotidine to lansoprazole for acid suppression and gastroprotective treatment, combined with Chinese patent medicine such as Kangfuxin Liquid. This is the first case report of a pharmacist in primary-level medical institutions adjusting drug use for patients with duodenal ulcer and pulmonary infection. CONCLUSION: A pharmacist participated in the treatment process, provided individualized medication adjustment, and achieved good clinical results.

6.
Foods ; 13(6)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38540922

RESUMO

Polygonum multiflorum Thunb. (PM) and derived products are broadly utilized in Chinese traditional medicine. According to our previous research, PM mostly contains polysaccharides, which display a wide range of biological activities. Two water-soluble polysaccharides (PMPs-1 and PMPs-2) were obtained from PM by DEAE-Cellulose and Sephadex G-100 column chromatography. Colorimetry, HPGPC-MALLS-RID, HPLC-PDA, methylation, FT-IR, NMR, and SEM were used to characterize these polysaccharides. PMPs-1 and PMPs-2 had average molecular weights of 255.5 and 55.7 kDa, respectively. PMPs-1 consisted of Man, Glc, Gal, and Ara at 0.9:78.6:1.0:1.6 and was a glucan with → 4)-Glcp-(1 → as a backbone. Meanwhile, PMPs-2, an acidic polysaccharide, comprised Rha, GalA, Glc, Gal, and Ara at 3.2:20.3:2.7:1.0:8.3. PMPs-1 and PMPs-2 significantly improved the proliferation of RAW 264.7 cells and induced NO, TNF-α, and IL-6 release. This study reveals that these two polysaccharides can be explored as novel immunomodulators and provide a basis for further development of PM in food and pharmaceutical industries.

7.
Front Cell Infect Microbiol ; 13: 1228940, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38053532

RESUMO

Background: There are several clinical and molecular predictors of responses to antidepressant therapy. However, these markers are either too subjective or complex for clinical use. The gut microbiota could provide an easily accessible set of biomarkers to predict therapeutic efficacy, but its value in predicting therapy responses to acupuncture in patients with depression is unknown. Here we analyzed the predictive value of the gut microbiota in patients with postpartum depressive disorder (PPD) treated with acupuncture. Methods: Seventy-nine PPD patients were enrolled: 55 were treated with acupuncture and 24 did not received any treatment. The 17-item Hamilton depression rating scale (HAMD-17) was used to assess patients at baseline and after eight weeks. Patients receiving acupuncture treatment were divided into an acupuncture-responsive group or non-responsive group according to HAMD-17 scores changes. Baseline fecal samples were obtained from the patients receiving acupuncture and were analyzed by high-throughput 16S ribosomal RNA sequencing to characterize the gut microbiome. Results: 47.27% patients responded to acupuncture treatment and 12.5% patients with no treatment recovered after 8-week follow-up. There was no significant difference in α-diversity between responders and non-responders. The ß-diversity of non-responders was significantly higher than responders. Paraprevotella and Desulfovibrio spp. were significantly enriched in acupuncture responders, and these organisms had an area under the curve of 0.76 and 0.66 for predicting responder patients, respectively. Conclusions: Paraprevotella and Desulfovibrioare may be useful predictive biomarkers to predict PPD patients likely to respond to acupuncture. Larger studies and validation in independent cohorts are now needed to validate our findings.


Assuntos
Terapia por Acupuntura , Transtorno Depressivo , Microbiota , Feminino , Humanos , Resultado do Tratamento , Transtorno Depressivo/terapia , Biomarcadores , Período Pós-Parto
8.
Toxics ; 11(12)2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-38133369

RESUMO

POP data are limited in the marine environment; thus, this study aimed to investigate background persistent organic pollutant (POP) levels in oceanic deep-water-deposited particulates in the South China Sea (SCS). Six POPs, including polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs), polychlorinated diphenyl ethers (PCDEs), and polybrominated biphenyls (PBBs), were investigated in eight pooled samples from the SCS from 20 September 2013 to 23 March 2014 and 15 April 2014 to 24 October 2014 at depths of 2000 m and 3500 m. PBDEs were the most predominant compounds, with the highest mean Σ14PBDE of 125 ± 114 ng/g dry weight (d.w.), followed by Σ17PCDD/F, Σ12PBDD/F, and Σ12DL-PCB (275 ± 1930, 253 ± 216, and 116 ± 166 pg/g d.w., respectively). Most PBDD/F, PBB, and PCDE congeners were below the detection limits. PCDDs had the highest toxic equivalency (TEQ), followed by PBDDs and DL-PCBs. Among the six POPs, PBDEs were the major components of the marine-deposited particles, regarding both concentrations and mass fluxes. Compared to 3500 m, PBDE levels were higher at a depth of 2000 m. PBDE mass fluxes were 20.9 and 14.2 ng/m2/day or 68.2 and 75.9 ng/m2/year at deep-water 2000 and 3500 m, respectively. This study first investigated POP levels in oceanic deep-water-deposited particles from existing global data.

9.
Zhongguo Zhong Yao Za Zhi ; 48(15): 4087-4096, 2023 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-37802776

RESUMO

To understand the current quality status and rearing situation of Bombyx Batryticatus, the authors collected 102 batches of Bombyx Batryticatus from different main producing areas and five major Chinese medicine markets from 2016 to 2018, and measured the properties and quality of the silk gland, to clarify the quality status of Bombyx Batryticatus from different producing areas and markets. In addition, 35 batches of Bombyx Batryticatus from 2019 to 2022 were used to verify the silk gland after revision. Moreover, Beauveria Bassiana was inoculated in the silkworm of 4-5 instars, and standardized rearing was carried out until they die. The death rate and the quality of Bombyx Batryticatus were measured to determine the differences in Bombyx Batryticatus of different instars, and explore the rationality of the infection age of Bombyx Batryticatus in Chinese Pharmacopoeia(2020). The results revealed that in the 102 batches of Bombyx Batryticatus, the qualification rate of silk gland was low; the content of total ash far exceeded the standard; the content of beauvericin varied greatly. The qualification rate of the silk gland of the 35 batches of Bombyx Batryticatus was only 47.49%, which could be increased to 73.00% if the number of silk gland was 2 to 4. The death rate of Bombyx Batryticatus at different infection ages was quite different, with uneven quality. Generally, the yield of Bombyx Batryticatus inoculated on the first day of the fifth instar was high with good quality. Therefore, in combination with the quality and actual production of Bombyx Batryticatus, the following suggestions were proposed for revision of Bombyx Batryticatus in Chinese Pharmacopoeia(2025): The number of silk gland should be revised as 2-4 bright brown or bright black silk glands, after which, the quality of Bombyx Batryticatus could be guaranteed, and the "quality identification based on character" could also be reflected scientifically; the content determination index that the content of beauvericin shall not be less than 0.017% should be added to better control the quality of Bombyx Batryticatus; the infection age should be revised as the first day of the fifth instar to narrow the age span, which could better fit the actual production and ensure the quality of Bombyx Batryticatus.


Assuntos
Bombyx , Medicina Tradicional do Leste Asiático , Animais , Seda , Larva
10.
Sheng Wu Gong Cheng Xue Bao ; 39(3): 912-929, 2023 Mar 25.
Artigo em Chinês | MEDLINE | ID: mdl-36994562

RESUMO

Chitosanases represent a class of glycoside hydrolases with high catalytic activity on chitosan but nearly no activity on chitin. Chitosanases can convert high molecular weight chitosan into functional chitooligosaccharides with low molecular weight. In recent years, remarkable progress has been made in the research on chitosanases. This review summarizes and discusses its biochemical properties, crystal structures, catalytic mechanisms, and protein engineering, highlighting the preparation of pure chitooligosaccharides by enzymatic hydrolysis. This review may advance the understandings on the mechanism of chitosanases and promote its industrial applications.


Assuntos
Quitosana , Quitosana/química , Quitina , Glicosídeo Hidrolases/genética , Engenharia de Proteínas , Oligossacarídeos/química , Hidrólise
11.
Biomed Chromatogr ; 37(1): e5526, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36250730

RESUMO

Because of the immense difficulty in identifying Cyathulae Capitatae Radix adulteration in Cyathulae Radix, this research aims at fortifying the quality control of Cyathulae Radix and its decoction pieces to guarantee the effectiveness and safety of its clinical use in terms of source material. A method was devised to identify Cyathulae Capitatae Radix adulteration in Cyathulae Radix and its decoction pieces. This research takes achybidensaponin I, that is, the characteristic component of Cyathulae Capitatae Radix, as reference substance and adopts HPLC for detection. The results revealed that, among all samples collected, no trace of achybidensaponin I was found in the 21 batches of Cyathulae Radix, whereas achybidensaponin I was found in all the 14 batches of Cyathulae Capitatae Radix. The research sets 5% as the adulteration limit, that is, 1.45 mg/g Cyathulae Capitatae Radix was detected in 57.14% of the 49 batches of market samples collected and the ratio was 51.02% in the case of 5% adulteration limit. The method is not only precise and reliable but can also be used as a supplement for provisions regarding quality control of Cyathulae Radix and its decoction pieces in Pharmacopoeia of the People's Republic of China, to effectively crack down on Cyathulae Capitatae Radix adulteration in the market.


Assuntos
Medicamentos de Ervas Chinesas , Humanos , Raízes de Plantas , Controle de Qualidade , Cromatografia Líquida de Alta Pressão , Contaminação de Medicamentos
12.
Front Public Health ; 10: 956463, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36530683

RESUMO

Objective: The aim of this study was to analyze the epidemiological characteristics of the causes of chronic kidney disease (CKD) stage 5 patients in North China and to investigate the economic burden of those on hemodialysis (HD) or peritoneal dialysis (PD), as well as the associated influencing factors. Methods: General clinical information, etiological categories, and hospitalization costs for HD or PD were collected from 1,515 patients hospitalized with stage 5 CKD at the Affiliated Hospital of Hebei University from 2016 to 2018. Logistic regression analysis was used to analyze the independent influencing factors affecting patients' financial burden. Results: The highest rate of DN was found in patients aged 70 years or older (27.0%) and the highest incidence of primary glomerulopathy was found in patients aged <50 years (24.3%). Age, type of dialysis, and type of health insurance were independent influences on the total financial burden of patients, and the results of multifactorial logistic regression analysis showed that age [OR (95% CI): 1.009 (1.002, 1.020)] and type of dialysis [OR (95% CI): 1.746 (1.149, 2.659)] would increase the total financial burden. The type of health insurance would reduce the total financial burden [OR (95% CI): 0.222 (0.108, 0.418)]. Conclusion: Chronic kidney disease, with its complex etiology and the heavy financial burden required for treatment, remains a more serious public health problem globally, and it is therefore necessary to further improve medical coverage for dialysis patients, increase management efforts, broaden pro-poor policies and increase the accessibility of medical services in low- and middle-income areas.


Assuntos
Falência Renal Crônica , Insuficiência Renal Crônica , Humanos , Pacientes Internados , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/terapia , Diálise Renal/métodos , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/terapia , China/epidemiologia
15.
Molecules ; 27(3)2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35163887

RESUMO

With the internationalization of traditional Chinese medicines (TCMs) and the increasing use of herbal medicines around the world, there are concerns over their safety. In recent years, there have been some sporadic reports of pesticide residues in Chuanxiong Rhizoma (CX), although the lack of systematic and comprehensive analyses of pesticide residues and evaluations of toxicological risks in human health has increased the uncertainty of the potential effects of pesticides exposure in humans. This study aimed to clarify the status of pesticide residues and to determine the health risks of pesticide residues in CX. The findings of this study revealed that 99 batches of CX samples contained pesticide residues ranging from 0.05 to 3013.17 µg/kg. Here, 6-22 kinds of pesticides were detected in each sample. Prometryn, carbendazim, dimethomorph, chlorpyrifos, chlorantraniliprole, pyraclostrobin, and paclobutrazol were the most frequently detected pesticides, with detection rates of 68.69-100%. Insecticides and fungicides accounted for 43.23% and 37.84% of the total pesticides detected, respectively. Here, 86.87% of the pesticide content levels were lower than 50 µg/kg, and a small number of samples contained carbofuran, dimethoate, and isofenphos-methyl exceeding the maximum residue levels (MRLs). A risk assessment based on the hazard quotient/hazard index (HQ/HI) approach revealed that the short-term, long-term, and cumulative risks of pesticide residues in CX are well below the levels that may pose a health risk. Worryingly, six banned pesticides (carbofuran, phorate sulfone, phorate-sulfoxide, isofenphos-methyl, terbufos-sulfone, and terbufoxon sulfoxide) were detected. This study has improved our understanding of the potential exposure risk of pesticide multi-residues in CX. The results of the study will have a positive impact on improving the quality and safety of CX and the development of MRLs for pesticide residues.


Assuntos
Cromatografia Gasosa/métodos , Cromatografia Líquida/métodos , Medicamentos de Ervas Chinesas/análise , Contaminação de Alimentos/análise , Medicina Tradicional Chinesa , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Humanos , Medição de Risco
16.
Front Endocrinol (Lausanne) ; 13: 992933, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36619566

RESUMO

Background: The incidence of diabetes mellitus (DM) in China is increasing yearly and has become a major problem plaguing national public health. The diagnosis of diabetic kidney disease (DKD) is based primarily on clinical criteria, and most patients do not receive a formal evaluation by renal biopsy; thus, misdiagnosis and underdiagnosis are common. The incidence of non-diabetic kidney disease (NDKD) is also higher in those with DM. To date, many cases of IgA nephropathy (IgAN) among those with DKD have been reported, while cases of IgAN in patients with long-duration DM who did not develop DKD are less commonly reported. Case description: A 70-year-old male patient with a diabetes duration of 26 years had proteinuria for one year. The clinical manifestations of nephrotic syndrome and IgAN were confirmed by renal biopsy. The patient received targeted treatment for three years with partial alleviation of proteinuria. Conclusion: Renal biopsy might aid in the definitive diagnosis of DKD, NDKD, and NDKD combined with DKD. Precise therapy based on renal pathology might help to improve outcomes in the kidney.


Assuntos
Diabetes Mellitus , Nefropatias Diabéticas , Glomerulonefrite por IGA , Masculino , Humanos , Idoso , Glomerulonefrite por IGA/complicações , Glomerulonefrite por IGA/diagnóstico , Glomerulonefrite por IGA/patologia , Rim/patologia , Nefropatias Diabéticas/complicações , Nefropatias Diabéticas/diagnóstico , Proteinúria/etiologia , Proteinúria/epidemiologia , Proteinúria/patologia , China , Diabetes Mellitus/patologia
17.
MethodsX ; 8: 101531, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34754800

RESUMO

Physical modeling is critical to study the performance of certain operation in heavy oil reservoirs. A well-designed experiment should guarantee the information gathered from lab would be applied to predict the thermal process in the field. To meet this requirement, the initial and boundary condition similarity between lab and field should be satisfied. It is reasonable to follow certain scaling criteria to fabricate the physical model. In addition to these conventional guidelines, this paper makes following recommendations to ensure a successful thermal recovery experiment,•To control and mitigate the steam channeling between the sand-pack and apparatus wall, the back wall is designed as it can be pushed enough to increase contact pressure.•Heat loss should be handled carefully, which impacting steam chamber growing and causing heat accumulation around the model.•A data acquisition system, based on PXI platform and Labview software, for the thermal recovery experiments had been proved valuable in evaluating the spreading progress of steam chamber.

18.
Biomed Chromatogr ; 35(12): e5211, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34216391

RESUMO

Chiral compounds commonly exist in traditional Chinese medicine (TCM), but little research on the quality control of TCM has been conducted. In this study, a new strategy is proposed, taking Yuanhuzhitong tablet [YHZT, consisting of Radix Angelicae Dahuricae and Rhizoma Corydalis (Yan Hu Suo, YHS)] for example, which is based on chiral isomer ratio analysis to monitor the production process of Chinese patent medicine companies. In the process of content determination for tetrahydropalmatine (THP) in YHZT from different companies, noticeable differences were observed in their chromatographic behaviors. It is known that THP has two enantiomers, naturally coexisting in YHS as a racemic mixture, so we prepared THP twice and subsequently performed chiral separation analysis using supercritical fluid chromatography. As a result, the peak area ratios of two enantiomers from different companies varied remarkably, demonstrating that some companies did not probably manufacture YHZT products in accordance with the prescription proportion, used inferior or extracted YSH crude materials in the production process, and added raw chemical medicine in the production to reach the standard and lower the costs. In conclusion, the peak area ratio of chiral isomers could be taken as a key quality index.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Medicamentos de Ervas Chinesas , Alcaloides de Berberina/análise , Alcaloides de Berberina/química , Medicamentos de Ervas Chinesas/análise , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/normas , Estereoisomerismo , Comprimidos
19.
Colloids Surf B Biointerfaces ; 202: 111692, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33744813

RESUMO

Chitosan oligosaccharides (COS) are attractive active molecules for biomedical applications. Currently, the prohibitively high cost of producing fully defined COS hampers extensive studies on their biological activity and restricts their use in various industries. Thus, cost-effective production of pure COS is of major importance. In this report, chitosanase from Bacillus subtilis MY002 (CsnMY002) was prepared for COS production. The structure of apo CsnMY002 displayed an unexpected tunnel-like substrate-binding site and the structure of the CsnMY002_E19A/(GlcN)6 complex highlighted the "4 + 2″ splitting of hexaglucosamine even though the "3 + 3″ splitting is also observed in the TLC analysis of the enzyme products for hexaglucosamine. Structure based rational design was performed to generate mutants for chitobiose production. The CsnMY002_G21 K mutant produced chitobiose with a relative content > 87 % from chitosan with a low degree of acetylation, and 50.65 mg chitobiose with a purity > 98 % was prepared from 100 mg chitosan. The results provide insight on the catalytic mechanism of chitosanase and underpin future biomedical applications of pure chitobiose.


Assuntos
Quitina , Quitosana , Dissacarídeos , Glicosídeo Hidrolases/genética , Oligossacarídeos
20.
Front Pharmacol ; 12: 818268, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35177984

RESUMO

In the present study, 168 pesticides in 1,017 samples of 10 Chinese herbal medicines (CHMs) were simultaneously determined by high-performance liquid (HPLC-MS/MS) and gas (GC-MS/MS) chromatography-tandem mass spectrometry. A total of 89.2% of the samples encompassed one or multiple pesticide residues, and the residue concentrations in 60.5% of samples were less than 0.02 mg kg-1, revealing the relatively low residue levels. The hazard quotient and hazard index methods were used to estimate the health risk for consumers. For a more accurate risk assessment, the exposure frequency and exposure duration of CHMs were involved into the exposure assessment, which was obtained from a questionnaire data of 20,917 volunteers. The results of chronic, acute, and cumulative risk assessment indicated that consumption of CHMs is unlikely to pose a health risk to consumers. Ranking the risk of detected pesticides revealed that phorate, BHC, triazophos, methidathion, terbufos, and omethoate posed the highest risk. Our results also showed that pollution of the aboveground medicinal part was more serious. Although exposure to pesticides in tested CHMs was below dangerous levels, more strict controlled management should be carried out for banned pesticides due to the high detection rate and illegal use in the actual planting practice.

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