Effects of different crosslinking treatments on the properties of decellularized small intestinal submucosa porous scaffolds / 北京大学学报(医学版)

OBJECTIVE@#To compare the effects of three different crosslinkers on the biocompatibility, physical and chemical properties of decellularized small intestinal submucosa (SIS) porous scaffolds.@*METHODS@#The SIS porous scaffolds were prepared by freeze-drying method and randomly divided into three groups, then crosslinked by glutaraldehyde (GA), 1-ethyl-3-(3-dimethylaminopropyl) carbodi-imide (EDC) and procyanidine (PA) respectively. To evaluate the physicochemical property of each sample in different groups, the following experiments were conducted. Macroscopic morphologies were observed and recorded. Microscopic morphologies of the scaffolds were observed using field emission scanning electron microscope (FESEM) and representative images were selected. Computer software (ImageJ) was used to calculate the pore size and porosity. The degree of crosslinking was determined by ninhydrin experiment. Collagenase degradation experiment was performed to assess the resistance of SIS scaffolds to enzyme degradation. To evaluate the mechanical properties, universal mechanical testing machine was used to determine the stress-strain curve and compression strength was calculated. Human bone marrow mesenchymal cells (hBMSCs) were cultured on the scaffolds after which cytotoxicity and cell proliferation were assessed.@*RESULTS@#All the scaffolds remained intact after different crosslinking treatments. The FESEM images showed uniformed interconnected micro structures of scaffolds in different groups. The pore size of EDC group[(161.90±13.44) μm] was significantly higher than GA group [(149.50±14.65) μm] and PA group[(140.10±12.06) μm] (P < 0.05). The porosity of PA group (79.62%±1.14%) was significantly lower than EDC group (85.11%±1.71%) and GA group (84.83%±1.89%) (P < 0.05). PA group showed the highest degree of crosslinking whereas the lowest swelling ratio. There was a significant difference in the swelling ratio of the three groups (P < 0.05). Regarding to the collagenase degradation experiment, the scaffolds in PA group showed a significantly lower weight loss rate than the other groups after 7 days degradation. The weight loss rates of GA group were significantly higher than those of the other groups on day 15, whereas the PA group had the lowest rate after 10 days and 15 days degradation. PA group showed better mechanical properties than the other two groups. More living cells could be seen in PA and EDC groups after live/dead cell staining. Additionally, the proliferation rate of hBMCSs was faster in PA and EDC groups than in GA group.@*CONCLUSION@#The scaffolds gained satisfying degree of crosslinking after three different crosslinking treatments. The samples after PA and EDC treatment had better physicochemical properties and biocompatibility compared with GA treatment. Crosslinking can be used as a promising and applicable method in the modification of SIS scaffolds.

Prevalência do autorrelato de depressão no Brasil: resultados da Pesquisa Nacional de Saúde, 2013 / Prevalence of self-reported depression in Brazil: 2013 National Health Survey results

RESUMO: Objetivo: Descrever a prevalência do autorrelato de diagnóstico médico prévio de depressão na população adulta brasileira (18 anos ou mais) segundo fatores sociodemográficos. Métodos: Foram utilizados dados da Pesquisa Nacional de Saúde 2013, inquérito de base populacional. Foi investigado o autorrelato do diagnóstico médico prévio de depressão, recebido em algum momento da vida. Foram calculadas as prevalências e seus respectivos intervalos de confiança de 95% (IC95%), estratificados por sexo, faixa etária, escolaridade, raça/cor da pele, para Brasil, local de residência, grandes regiões, unidades federativas e capitais. Resultados: A prevalência de autorrelato de diagnóstico de depressão em adultos no Brasil foi de 7,6% (IC95% 7,2 - 8,1), sendo maior em mulheres (10,9%; IC95% 10,3 - 11,6) e em pessoas entre 60 e 64 anos (11,1%; IC95% 9,1 - 13,1). Ainda, as maiores prevalências foram em indivíduos sem instrução ou com fundamental incompleto, 8,6% (IC95% 7,9 - 9,3), para aqueles com ensino superior completo, 8,7% (IC95% 7,5 - 9,9); e para aqueles que se autodeclararam brancos (9,0%; IC95% 8,3 - 9,6). Por local de residência, esse autorrelato foi maior em indivíduos residentes na região urbana (8,0%; IC95% 7,5 - 8,4) e na região Sul (12,6%; IC95% 11,2 - 13,9). Conclusão: A análise deste estudo revela a importância de conhecer o acesso ao diagnóstico de depressão no Brasil. É necessário aprimorar o acesso aos serviços de saúde com qualidade em todo o território nacional para abranger as populações mais desfavorecidas. Reduzir as disparidades no acesso aos serviços de saúde é fundamental para garantir que direitos sociais sejam equânimes e universais.

ABSTRACT: Objective: To describe the prevalence of self-reported previous medical diagnosis of depression in the adult (18 years or older), Brazilian population according to sociodemographic factors. Methods: Data from the 2013 National Health Survey, a population-based survey, were used. The self-reported previous medical diagnosis of depression, received at some point during the patient's life, was investigated. Prevalence and their respective confidence intervals of 95% (CI 95%) were calculated, stratified by gender, age group, education level, race/skin color, for Brazil, place of residence, major regions, federative units and capitals. Results: The prevalence of self-reported diagnosis of depression in adults in Brazili was of 7.6% (95%CI 7.2 - 8.1), being higher in women (10.9%; 95%CI 10.3 - 11.6) and among people between 60 and 64 years old (11.1%; 95%CI 9.1 - 13.1). Furthermore, the highest prevalence was among individuals with no formal education or those with incomplete primary education 8.6% (95%CI 7.9 - 9.3), for those with complete tertiary education 8.7% (95%CI 7.5 - 9,9); and for those who declared themselves as white (9.0%; 95%CI 8.3 - 9.6). For place of residence, the self-report was higher in individuals living in urban areas (8.0%; 95%CI 7.5 - 8.4) and in the South (12.6%; 95%CI 11.2 - 13.9). Conclusion: The analysis shows the importance of understanding the access to the diagnosis of depression in Brazil. It is necessary to improve access to quality health services throughout the country to include the underprivileged population. Reducing disparities in access to health services is crucial to ensuring that social rights are universal and equal.

Preparation of cross-linked carboxymethyl jackfruit starch and evaluation as a tablet disintegrant

The main purposes of this study are to prepare cross-linked carboxymethyl jackfruit starch [CL-CMJF] and to evaluate its pharmaceutical property as a tablet disintegrant. CL-CMJF was prepared by a dual carboxymethyl-crosslinking reaction in a flask containing jackfruit seed starch [JFS], chloroacetic acid [CAA], sodium hydroxide [NaOH] and sodium trimetaphosphate [STMP]. The reaction was carried out using methanol as a solvent for 60 min at 70°C and at JFS:CAA:NaOH:STMP ratio of 1.0:0.29:0.28:0.07. The obtained CL-CMJF, with degree of substitution and degree of crosslinking calculated to be 0.34 and 0.06, respectively, was insoluble but swellable in water. Rheological study revealed a decreased in solution viscosity compared to the non-crosslinked CMJF. The water uptake of CL-CMJF was 23 times higher than that of native starch and was comparable to that of a commercial superdisintegrant, sodium starch glycolate [SSG]. The swelling ability of CL-CMRS was similar to that of crosscarmellose sodium [CCS], another commercial superdisintegrant. Disintegration test of aspirin tablets containing 2%w/w of JFS, CL-CMJF, SSG and CCS showed disintegration times in the order of SSG < CCS CL-CMJF <<< JFS. The results suggested that CL-CMJF could be developed as a tablet disintegrant

Labeling Efficacy of Superparamagnetic Iron Oxide Nanoparticles to Human Neural Stem Cells: Comparison of Ferumoxides, Monocrystalline Iron Oxide, Cross-linked Iron Oxide (CLIO)-NH2 and tat-CLIO

OBJECTIVE: We wanted to compare the human neural stem cell (hNSC) labeling efficacy of different superparamagnetic iron oxide nanoparticles (SPIONs), namely, ferumoxides, monocrystalline iron oxide (MION), cross-linked iron oxide (CLIO)-NH2 and tat-CLIO. MATERIALS AND METHODS: The hNSCs (5x105 HB1F3 cells/ml) were incubated for 24 hr in cell culture media that contained 25 microgram/ml of ferumoxides, MION or CLIO-NH2, and with or without poly-L-lysine (PLL) and tat-CLIO. The cellular iron uptake was analyzed qualitatively with using a light microscope and this was quantified via atomic absorption spectrophotometry. The visibility of the labeled cells was assessed with MR imaging. RESULTS: The incorporation of SPIONs into the hNSCs did not affect the cellular proliferations and viabilities. The hNSCs labeled with tat-CLIO showed the longest retention, up to 72 hr, and they contained 2.15+/-0.3 pg iron/cell, which are 59 fold, 430 fold and six fold more incorporated iron than that of the hNSCs labeled with ferumoxides, MION or CLIO-NH2, respectively. However, when PLL was added, the incorporation of ferumoxides, MION or CLIO-NH2 into the hNSCs was comparable to that of tat-CLIO. CONCLUSION: For MR imaging, hNSCs can be efficiently labeled with tat-CLIO alone or with a combination of ferumoxides, MION, CLIO-NH2 and the transfection agent PLL.

Modification of ovine luteinizing hormone subunits with SMPT and its effect on subunit recombination, immunological activity, receptor binding and steroidogenic activity.

The increasing use of heterobifunctional cross-linking agents in the design of defined conjugates for selective targeting and inducing immune response has prompted us to study the role of epsilon-NH2 group modification of oLH subunits, their recombination and effect on immunoreactivity, receptor binding and biological activity. The epsilon-NH2 groups of alpha oLH and beta oLH subunits were separately modified by using SMPT. The alpha oLH-SMPT modified derivatives hybridize to beta oLH. Similarly, the beta oLH-SMPT derivatives recombined with alpha oLH. The recombination was judged by gel filtration chromatography and RP-HPLC analysis. The sequential modification of subunits led to progressive reduction in immunoreactivity and receptor binding activity. The modification of six or more epsilon-NH2 groups in alpha oLH although recombine fully with native beta oLH but failed to react to anti-oLH antibody. Moreover, the steroidogenic activity was also abolished. Introduction upto four SMPT groups in alpha oLH compromised immunological and biological activities but further addition of two or more SMPT groups completely abolished antibody reactivity, receptor binding and steroidogenic activity indicating the importance of later two amino groups in the receptor binding and steroidogenic activity. The present investigation clearly demonstrate that only 1:2-3 molar ratio of oLH subunits:SMPT could generate the site(s) in the subunits of the oLH that retained reasonable immunological, receptor binding and biological activity of the hormone. Therefore, this molar ratio may be used in future for the design and synthesis of bioeffective hormonotoxins.

Effect of sulphur crosslinking on the stability and transition of triple helical DNA.

In continuation to our work on order-order and order-disorder transition in triple stranded DNA when it is bounded to netropsin, we report in this communication the stabilizing/destabilizing effect of disulphide linkage on the phase dynamics of the triplex using the amended Zimm-Bragg theory. It is observed that in contrast to the sequential triplex-->duplex -->single strand melting of the uncrosslinked triplex, crosslinking causes the triplex state to melt directly to the single stranded state, with no apparent intermediary of a duplex state. Since there is no overall difference in the enthalpy of crosslinked and uncrosslinked triplexes, the transition is entropy driven.