Lignan constituents of Tilia amurensis and their biological evaluation on antitumor and anti-inflammatory activities

In the recent decade, numerous lignan derivatives isolated from plants have been proven to have the potential as an anti-cancer substance. On the search for anti-cancer compounds from Korean medicinal plants, the methanolic extract from the trunk of Tilia amurensis Rupr. (Tiliaceae) was found to have significant cytotoxicity against A549 (lung carcinoma), SK-OV-3 (ovary malignant ascites), SK-MEL-2 (skin melanoma), and HCT-15 (colon adenocarcinoma) in our screening test. Hence, a bioassay-guided fractionation and chemical investigation of the methanolic extract resulted in the isolation and identification of 10 lignan derivatives (1–10) including two new lignan glycosides named tiliamurosides A (1) and B (2). The structures of these new compounds were determined by spectroscopic methods, namely 1D and 2D nuclear magnetic resonance (NMR) techniques, high resolution mass spectrometry (HRMS), circular dichroism (CD) data, and chemical methods. Tiliamuroside B (2) and schizandriside (3) showed significant cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines with inhibitory concentration (IC₅₀) values of 3.26–8.89 μM. Moreover, (−)-syringaresinol (8) and (−)-pinoresinol 4-O-β-d-glucopyranoside (10) significantly inhibited nitric oxide (NO) production in murine microglia BV-2 with IC₅₀ values of 15.05 and 34.35 μM, respectively.     

The Parental Bond and Alcohol Use Among Adolescents: The Mediating Role of Drinking Motives

Background: Alcohol use and alcohol-related problems represent a significant health concern. Few empirical researches focused on understanding the interrelationships and links between the parental bond, drinking motives, and alcohol use during adolescence.

Objectives: The present study examined the relationships between a supportive parental bond, drinking motives, and alcohol use, with a focus on the role of mediation.

Methods: The sample comprised 298 adolescents, aged from 16 to 20 years. The technique of structural equation modelling (SEM) was used to assess the direct and indirect effects of the parental bond on alcohol use among adolescents through motives for drinking.

Results: The relationship between the parental bond and frequency of alcohol use by adolescents was not mediated by any motives for drinking, neither for males nor females. Regarding the relationships between the parental bond and quantity of adolescent alcohol consumption, findings for females showed significant indirect effects of maternal bond on alcohol quantity, when coping, enhancement, and social drinking motives were entered as mediator variables. Rather, paternal bond did not predict drinking quantity, not even indirectly. On the contrary, results for males indicated that the parental bond was neither directly nor indirectly associated with adolescent alcohol use.

Conclusions/Importance: Mothers are the relational fulcrum of the family, while fathers seem to maintain a more peripheral position. Gender differences are discussed on the basis of the different cultural and parental socialisation processes that operate for male and female adolescents.     

Identification and quantification of degradations in the Asp-Asp motifs of a recombinant monoclonal antibody

Two degradations of aspartate residues located in Asp-Asp motifs in the CDR3 region of a recombinant monoclonal antibody were identified and quantified after the antibody was aged in a mildly acidic buffer at elevated temperatures. The degraded sample aged at 25 degrees C for 1 month generated 1.8% antibody molecules that had isomerization in the aspartate residues, while the degraded sample after aging at 45 degrees C for 1 month contained 7% isomerization. Peptide bond cleavages at the aspartate residues were also detected and characterized. The percentage of clipped antibody molecules after 1 month of storage was 1% at 25 degrees C and 4.4% at 45 degrees C. The generated cleaved polypeptides were noncovalently attached to the intact antibody molecule and were not involved in the aggregation formation. They were not detected by native size-exclusion chromatography because of their strong non-covalent association to the rest of the antibody molecules. On the other hand, the cleaved polypeptides were dissociated and detected as fragments under denaturing conditions of reversed-phase HPLC, denaturing size-exclusion chromatography and MALDI-TOF mass spectrometry. It was demonstrated that the cleavages at the above aspartate residue sites occurred due to the aging of the sample at elevated temperatures and were not method-induced by the reversed-phase HPLC and other methods used in this study.     

Complement C3 isoforms in Austrelaps superbus

Complement C3 plays a pivotal role in both classical and alternate pathways. Lower organisms (urochordates and fishes) have multiple isoforms whereas higher organisms have a single C3 gene. In cobras, a closely related protein cobra venom factor (CVF) is expressed in their venom gland. We have recently shown that Austrelaps superbus contains two isoforms (AVF-1 and AVF-2) of CVF-like proteins in the venom gland. To understand the origin of these proteins and their similarity to C3 protein, we examined C3-like proteins in the liver. Here we describe the complete cDNA sequences of two isoforms (AsC3-1 and AsC3-2) of complement C3 found in A. superbus liver. This is the first report of molecular isoforms of C3 in a reptilian organism. These isoforms display the overall domain structure of complement C3 proteins. Real-time quantitative analysis shows that there is a 144-fold difference in their mRNA expression levels. We also demonstrate by Southern blot experiments that the venom gland isoforms (AVF-1 and AVF-2) and the liver isoforms (AsC3-1 and AsC3-2) are the products of four individual genes. The putative promoter regions of these four genes are highly similar ( approximately 99% identical) to each other. These genes represent a unique case where despite being identical at the genomic level, exhibit tissue specificity and differential gene regulation. These genes offer a system to identify the tissue-specific regulatory proteins that are responsible for the constitutive expression of complement C3 in liver and inducible expression of AVF genes in the venom gland of A. superbus.     

Chemical synthesis of β‐defensins and LEAP‐1/hepcidin

Abstract: A large and steadily growing subfamily of antimicrobially active peptides of animals and plants is formed by the defensins, which are highly disulfide‐bonded, cationic peptides with a molecular mass of about 4 kDa. The synthesis of the human β‐defensins 1 and 2 (hBD‐1, hBD‐2) as well as of the novel murine β‐defensins 7 and 8 (mBD‐7 and mBD‐8) is reported. The peptides were synthesized by solid‐phase peptide synthesis using fluorenylmethoxycarbonyl chemistry. The linear products were oxidized in the presence of the cysteine/cystine redox system to the biologically active molecules. The correct disulfide connectivity of the resulting cyclic products was partly verified by mass spectrometry and sequence analysis of the fragments obtained after tryptic cleavage. In addition, the recently discovered antimicrobially active human peptide LEAP‐1/hepcidin, which contains four disulfide bonds, was successfully synthesized and subsequently oxidized. For Liver‐expressed anti microbial peptide (LEAP)‐1/hepcidin and hBD‐1, the identity of native and synthetic peptides was demonstrated by high‐pressure liquid chromatography and capillary electrophoretic analysis. The general synthetic procedure is suitable to rapidly perform the total chemical synthesis of novel fully bioactive defensins, which are expected to be identified soon, as well as of structurally modified analogs.     

对钴铬合金舌侧翼板粘结桥的粘结面处理的研究

目的：通过对粘结桥的粘结面不同处理的粘结强度测试,为临床应用提供理论依据。方法：选用钴铬合金,铸造成一定规格的（１０ｍｍ×１０ｍｍ×１ｍｍ）板,随机分成５组,以电蚀、喷砂方法处理,用高真空喷镀仪及万能金相显微镜观察,抗剪粘结强度测试,并作统计分析。结果：抗剪粘结强度由强到弱依次为：单纯电蚀;喷砂后电蚀;单纯喷砂;电蚀后喷砂;磨光。结论：对制作钴铬合金舌侧翼板粘结桥的粘结面以电蚀处理为首选;而单纯喷砂处理亦可提高粘结强度,为临床应用提供了方便、易操作的方法。     

酪蛋白磷酸多肽钙磷复合体的应用顺序对乳牙牙本质粘结强度的影响

目的探讨酪蛋白磷酸多肽钙磷复合体(casein phosphopetide-amorphic calcium phosphat, CPP-ACP)应用顺序对乳牙牙本质粘结强度及对乳牙牙本质小管封闭作用的影响。方法选取人56颗无龋乳磨牙,磨除牙合面釉质,制备牙本质平面。将其中48颗乳磨牙随机分3大组(n=16)。A组:仅酸蚀15 s。B组:涂CPP-ACP后酸蚀15 s。C组:酸蚀15 s后涂CPP-ACP。各组分为2小组(n=8),其中AN,BN,CN组使用Prime&Bond NT(NT)全酸蚀粘结剂,AS,BS,CS组使用Single bond 2(SB2)全酸蚀粘结剂。制作树脂粘结试件,电子万能试验机测定剪切强度(SBS值)。其余8个乳磨牙随机分成4组(n=2),分别为空白组(S1组)、酸蚀组(S2组)、酸蚀后涂CPP-ACP组(S3组)、涂CPP-ACP后酸蚀组(S4组)分别用扫描电镜观察粘结前牙本质小管封闭情况。结果剪切实验结果为AN组、BN组、CN组剪切强度无统计学差异(P>0.05);AS组,BS组,CS组剪切强度也无统计学差异(P>0.05);AN组>AS组,BN组>BS组,CN组>CS组差异有统计学意义(P<0.05)。扫描电镜结果为S3组中牙本质小管封闭数目最多。结论在酸蚀后应用CPP-ACP处理乳牙牙本质不影响NT和SB2两种全酸蚀粘结剂的粘结强度;可以达到有效的牙本质小管封闭;Prime&Bond NT(NT)全酸蚀粘结系统的粘结强度高于Single bond 2(SB2)。     

Synthesis and activity of novel glutathione analogues containing an urethane backbone linkage

The new GSH analogues H-Glo(-Ser-Gly-OH)-OH (5), its O-benzyl derivative 4, and H-Glo(-Asp-Gly-OH)-OH (9), characterized by the replacement of central cysteine with either serine or aspartic acid, and containing an urethanic fragment as isosteric substitution of the scissile gamma-glutamylic junction, have been synthesized and characterized. Their ability to inhibit human GST P1-1 (hGST P1-1) in comparison with H-Glu(-Ser-Gly-OH)-OH and H-Glu(-Asp-Gly-OH)-OH, which are potent competitive inhibitors of rat GST 3-3 and 4-4, has been evaluated. In order to further investigate the effect of the isosteric substitution on the binding abilities of the new GSH analogues 4, 5 and 9, the previously reported cysteinyl-containing analogue H-Glo(-Cys-Gly-OH)-OH has been also evaluated as a co-substrate for hGSTP1-1.