Progressive failure analysis of perforated composite laminates considering nonlinear shear effect

Composites are widely used in high performance structures such as aerospace structures due to their excellent properties. The analysis of failure evolution of composite perforated structures by finite element simulation is of great significance for practical work as engineering composite structures often contain notches and voids. In this paper, the numerical simulation of failure evolution and failure modes of carbon fiber reinforced resin composite laminates with large openings was carried out. A UMAT subroutine was written based on the 3D Hashin-Ye failure criterion and progressive damage model theory. The characteristic length and viscosity coefficient were introduced into the model to reduce mesh dependency and improve computational convergence. The nonlinear shear constitutive relationship defined by the Ramberg-Osgood equation was introduced into the continuous damage degradation model. The effect of nonlinear shear on the failure evolution of laminates with different stacking sequence was studied.

Antimicrobial activity of natural and semi-synthetic carbazole alkaloids

Since the first natural carbazole alkaloid, murrayanine, was isolated from Mwraya Spreng, carbazole alkaloid derivatives have been widely concerned for their anti-tumor, anti-viral and anti-bacterial activities. In recent decades, a growing body of data suggest that carbazole alkaloids and their derivatives have different biological activities. This is the first comprehensive description of the antifungal and antibacterial activities of carbazole alkaloids in the past decade (2012-2022), including natural and partially synthesized carbazole alkaloids in the past decade. Finally, the challenges and problems faced by this kind of alkaloids are summarized. This paper will be helpful for further exploration of this kind of alkaloids.

Efficacy of pterostilbene suppression on Aspergillus flavus growth, aflatoxin B1 biosynthesis and potential mechanisms

Aspergillus flavus, a widespread saprotrophic filamentous fungus, could colonize agricultural crops with aflatoxin contamination, which endangers food security and the agricultural economy. A safe, effective and environmentally friendly fungicide is urgently needed. Pterostilbene, a natural phytoalexin originated from Pterocarpus indicus Willd., Vaccinium spp. and Vitis vinifera L., has been reported to possess excellent antimicrobial activity. More importantly, it is quite safe and healthy. In our screening tests of plant polyphenols for the inhibition of A. flavus, we found that pterostilbene evidently inhibited mycelial growth of Aspergillus flavus (EC50 = 15.94 μg/mL) and the inhibitory effect was better than that of natamycin (EC50 = 22.01 μg/mL), which is a natural product widely used in food preservation. Therefore, we provided insights into the efficacy of pterostilbene suppression on A. flavus growth, aflatoxin B1 biosynthesis and its potential mechanisms against A. flavus in the present study. Here, pterostilbene at concentrations of 250 and 500 μg/mL could effectively inhibit the infection of A. flavus on peanuts. And the biosynthesis of the secondary metabolite aflatoxin B1 was also inhibited. The antifungal effects of pterostilbene are exerted by inducing a large amount of intracellular reactive oxygen species production to bring the cells into a state of oxidative stress, damaging cellular biomolecules such as DNA, proteins and lipids and destroying the integrity of the cell membrane. Taken together, our study strongly supported the fact that pterostilbene could be considered a safe and effective antifungal agent against A. flavus infection.

The Antifungal Mechanism of Isoxanthohumol from Humulus lupulus Linn

Humulus lupulus Linn. is a traditional medicinal and edible plant with several biological properties. The aims of this work were: (1) to evaluate the in vitro antifungal activity of H. lupulus ethanolic extract; (2) to study the in vitro and in vivo antifungal activity of isoxanthohumol, an isoprene flavonoid from H. lupulus, against Botrytis cinerea; and (3) to explore the antifungal mechanism of isoxanthohumol on B. cinerea. The present data revealed that the ethanolic extract of H. lupulus exhibited moderate antifungal activity against the five tested phytopathogenic fungi in vitro, and isoxanthohumol showed highly significant antifungal activity against B. cinerea, with an EC₅₀ value of 4.32 µg/mL. Meanwhile, it exhibited moderate to excellent protective and curative efficacies in vivo. The results of morphologic observation, RNA-seq, and physiological indicators revealed that the antifungal mechanism of isoxanthohumol is mainly related to metabolism; it affected the carbohydrate metabolic process, destroyed the tricarboxylic acid (TCA) cycle, and hindered the generation of ATP by inhibiting respiration. Further studies indicated that isoxanthohumol caused membrane lipid peroxidation, thus accelerating the death of B. cinerea. This study demonstrates that isoxanthohumol can be used as a potential botanical fungicide for the management of phytopathogenic fungi.

[ClinicaAnalysis of osteosclerotic protein expression and bacterial distribution in periodontitis patients at different stages]

PURPOSE

To investigate the osteosclerin level and bacterial distribution in periodontitis patients at different stages, and to analyze the correlation between osteosclerin and the parameters of conventional periodontal examination.

METHODS

Patients with periodontitis admitted to Guangzhou Huadu Maternal and Child Health Hospital from March 2017 to June 2019 were selected and divided into stage Ⅱ group (n=27), stage Ⅲ group (n=42) and stage Ⅳ group (n=22) according to the severity of periodontitis; meanwhile, 30 healthy individuals underwent physical examination in our hospital during the same period were selected as control group. Gingival crevicular fluid and plaque at buccal and lingual sites were collected for bacterial culture. The expression of osteosclerotin in gingival crevicular fluid was detected by enzyme-linked immunosorbent assay. The data were processed by SPSS 23.0 software package. Spearman correlation analysis was used to analyze the correlation between BI grade and osteosclerin, and correlation between PD, CAL and osteosclerin was determined by Pearson analysis.

RESULTS

The mean PD and mean CAL of patients in stage Ⅱ group before and after treatment were significantly smaller than those in stage Ⅲ and Ⅳ group (P<0.05). The mean CAL of stage Ⅳ group before treatment was significantly greater than that of stage Ⅲ group (P<0.05). After treatment, the mean PD and mean CAL of three groups were all significantly smaller than those before treatment (P<0.05). The mean PD in stage Ⅲ group was significantly lower than that in stage Ⅳ group after treatment (P<0.05). Before treatment, the proportion of BI grade 2 in stage Ⅱ group was significantly higher than that in stage Ⅲ and Ⅳ group (85.19%, 19.05%, 18.18%, P<0.05). Before treatment, the proportion of BI grade 3 in stage Ⅲ group was significantly higher than that in stage Ⅱ group (64.29%, 14.81%, P<0.05). Before the treatment, the expression of osteosclerosis protein in stage Ⅱ group was significantly lower than that in stage Ⅲ and Ⅳ group (P<0.05). The levels of osteosclerin expression of three groups after treatment were all significantly lower than those before treatment (P<0.05). The expression of osteosclerosis protein in stage Ⅱ group was significantly lower than that in stage Ⅲ and Ⅳ group after treatment (P<0.05). PD, CAL and BI of patients with different stages of periodontitis were positively correlated with osclerosin in gingival crevicular fluid before and after treatment (P<0.05). The number of bacteria detected in stage Ⅳ group was significantly higher than that in stage Ⅲ group and stage Ⅱ group. The main bacteria in each group were anaerobic bacteria. The dominant bacteria were Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetes, Fusobacterium nucleatum, and Prevotella melaninogenicus.

CONCLUSIONS

The expression level of osteosclerosin is closely related to PD, CAL and BI grades in patients with periodontitis, and bacterial colonization levels in gingival crevicular fluid and dental plaque in patients with periodontitis at different stages are different. Detection of osclerosin level and identification of periodontal microorganism culture have high clinical value in clinical diagnosis of periodontitis severity and can provide reference for selection of subsequent treatment plan.

[Evaluation of 93 cases of mandibular first molar root bifurcation lesions treated with autologous dentin Granules combined with platelet-rich fibrin membrane]

PURPOSE

To investigate the efficacy of autologous dentin particles combined with platelet-rich fibrin membrane (PRF) in the treatment of root bifurcation lesions of mandibular first molar.

METHODS

Ninety-three patients (93 teeth) with mandibular first molar root bifurcation lesions were selected from our department from February 2016 to October 2017. They were randomly divided into 2 groups. Forty-six patients with 46 teeth in the experimental group underwent autologous dentin particles combined with platelet-rich fibrin membrane, while patents in the control group (47 patients with 47 teeth) were treated with Bio-Oss implanted in the bone defect area covered with collagen membrane. The patients were revisted at 1, 3, 6 and 12 months after operation. The success rate of the operation group, the depth of periodontal pocket (PD), the loss of attachment (AL), the depth of penetration of the root bifurcation (HPD), and the bone density of the root bifurcation area before and after treatment. The data were recorded and compared with SPSS25.0 software package.

RESULTS

The success rate was 97.83%(45/46) in the experimental group, 85.11%(40/47) in the control group, the difference between the two groups was significant(P<0.05). After treatment, PD, AL and HPD decreased significantly (P<0.05), and MGVs increased gradually. There was no significant difference in MGVs before treatment and 1 month after treatment in the experimental group (P>0.05). MGVs at other time points were significantly higher than those of the control group (P<0.05). PD, AL and HPD of the experimental group were lower significantly than the control group at each time point after treatment (P<0.05), and MGVs value was significantly higher than the control group (P<0.05). There was no significant difference in the incidence of complications(4.35% vs 6.38%, χ²=0.189, P>0.05).

CONCLUSIONS

Autologous dentin particles combined with platelet-rich fibrin membrane is effective for the treatment of root bifurcation lesions of mandibular first molar, which is worthy of wide application.

Combined gastroscopic and choledochoscopic transabdominal nasobiliary drainage

Common bile duct (CBD) stones are a frequent problem in Chinese populations, and their incidence is particularly high in certain areas (Wang et al., 2013). In recent years, laparoscopic common bile duct exploration (LCBDE) and endoscopic retrograde cholangiopancreatography (ERCP) have been the main surgical procedures for CBD stones, although each has different advantages and disadvantages in the treatment of choledocholithiasis (Loor et al., 2017; Zhou et al., 2017). For patients with large stones, a dilated CBD, especially concurrent gallstones, LCBDE is the preferred and most economical minimally invasive procedure (Koc et al., 2013). However, a T-tube is often placed during LCBDE to prevent postoperative bile leakage; this is associated with problems such as bile loss, electrolyte disturbance, and decreased gastric intake (Martin et al., 1998). In addition, the T-tube usually must remain in place for more than a month, during which time the patient's quality of life is seriously compromised. Many skilled surgeons currently perform primary closure of the CBD following LCBDE, which effectively speeds up rehabilitation (Hua et al., 2015). However, even in sophisticated medical centers, the incidence of postoperative bile leakage still reaches ≥10% (Liu et al., 2017). Especially for a beginner, bile leakage remains a key problem (Kemp Bohan et al., 2017). Therefore, a safe and effective minimally invasive surgical approach to preventing bile leakage during primary closure of the CBD after LCBDE is still urgently needed.

Phenolic compounds from cultivated Glycyrrhiza uralensis and their PD-1/PD-L1 inhibitory activities

One new compound (1) and fifteen known phenolic compounds (2-16) were isolated and identified from the roots and rhizomes of Glycyrrhiza uralensis, including ten flavonoids, four coumarins, and two benzofurans compounds. Their structures were identified by NMR and MS analysis. Most of these compounds showed weak PD-1/PD-L1 inhibitory activities with the inhibition ratios from 30 to 65% at 100 uM. To our knowledge, it is the first time that their PD-1/PD-L1 inhibition activities were reported.

Clinical Effect of Adjuvant Cytokine-Induced Killer Cells Immunotherapy in Patients with Stage II-IVB Nasopharyngeal Carcinoma after Chemoradiotherapy: A propensity score analysis

As an adjuvant immunotherapy, cytokine-induced killer cells (CIKs) infusion has been demonstrated to exert potent effectiveness in several types of cancer patients who received curative treatment. However, controversy exists regarding whether nasopharyngeal carcinoma (NPC) patients can benefit from additional treatment after radical radiotherapy or chemoradiotherapy to improve their distant control and survival. In this retrospective study, we aimed to evaluate the efficacy of adjuvant CIK cells therapy in NPC patients with stage II-IVB after curative treatment. From January 1, 2005 to December 31, 2012, 85 pairs of NPC patients matching by propensity score matching (PSM) method to balance prognostic factors were included in this study: 85 cases underwent radical treatment, 85 cases received radical treatment and sequential CIKs infusion. We found that disease-free survival (DFS) and overall survival (OS) were significantly better in the CIK group than that in the control group (P = 0.009, P < 0.001, respectively). Adjuvant CIK cells immunotherapy was showed to be an independent prognostic factor for survival of the patients in further multivariate analysis. In subgroup analyses, the DFS and OS of patients with T3/4, III and IV A-B TNM (tumor-node-metastasis) stages were significantly enhanced in CIK group compared to control group. Nevertheless, both NPC patients with high and low EBV DNA benefited from adjuvant CIK cells immunotherapy. In conclusion, CIKs infusion is an effective adjuvant immunotherapy for enhancing the prognosis of NPC patients who have received the standard treatment, particularly for those with more aggressive tumor (T3/4) or advanced TNM stage.

HUS1 checkpoint clamp component (HUS1) is a potential tumor suppressor in primary hepatocellular carcinoma

The HUS1 checkpoint clamp component (HUS1), which is a member of an evolutionarily conserved, genotoxin-activated checkpoint complex (Rad9-Rad1-Hus1 [9-1-1] complex), is involved in cell cycle arrest and DNA repair in response to DNA damage. We conducted this study to investigate the biological significances of HUS1 expression in hepatocellular carcinoma (HCC) development. The mRNA and protein expression levels of HUS1 were determined using Real-time PCR and Western blot, respectively. One hundered and twenty four paraffin sections from HCC tissues were analyzed by immunohistochemistry to assess the association between HUS1 expression and clinicopathological characteristics of patients. The Kaplan-Meier method was performed to calculate the OS and RFS curves. Cell proliferation and colony formation assays, cell migration and invasion assays and cell cycle assays were used to determine the suppressor role of HUS1 in vitro. A mouse model was used to determine the effect of HUS1 on tumorigenesis. The expression of HUS1 was significantly decreased in HCC cell lines and tissues, and low HUS1 expression was associated with poor prognosis of HCC patients. Upregulation of HUS1 expression inhibited the cell proliferation, colony formation, migration, and invasion, as well as arrested cell cycle at G0/G1 in HCC cells in vitro. Moreover, sufficient HUS1 expression inhibited the tumor growth in nude mice. Our study revealed for the first time that HUS1 is a potential tumor suppressor that might produce an antitumor effect in human HCC. Furthermore, HUS1 may serve as a prognostic indicator and could be used for therapeutic application in HCC patients.

Increasing the immune activity of exosomes: the effect of miRNA-depleted exosome proteins on activating dendritic cell/cytokine-induced killer cells against pancreatic cancer

BACKGROUND

Tumor-derived exosomes were considered to be potential candidates for tumor vaccines because they are abundant in immune-regulating proteins, whereas tumor exosomal miRNAs may induce immune tolerance, thereby having an opposite immune function.

OBJECTIVE

This study was designed to separate exosomal protein and depleted exosomal microRNAs (miRNAs), increasing the immune activity of exosomes for activating dendritic cell/cytokine-induced killer cells (DC/CIKs) against pancreatic cancer (PC).

METHODS

PC-derived exosomes (PEs) were extracted from cultured PANC-1 cell supernatants and then ruptured; this was followed by ultrafiltered exosome lysates (UELs). DCs were stimulated with lipopolysaccharide (LPS), PE, and UEL, followed by co-culture with CIKs. The anti-tumor effects of DC/CIKs against PC were evaluated by proliferation and killing rates, tumor necrosis factor-α (TNF-α) and perforin secretion. Exosomal miRNAs were depleted after lysis and ultrafiltration, while 128 proteins were retained, including several immune-activating proteins.

RESULTS

UEL-stimulated DC/CIKs showed a higher killing rate than LPS- and PE-stimulated DC/CIKs.

CONCLUSIONS

miRNA-depleted exosome proteins may be promising agonists for specifically activating DC/CIKs against PC.

Inhibition of invasion by N-trans-feruloyloctopamine via AKT, p38MAPK and EMT related signals in hepatocellular carcinoma cells

N-trans-feruloyloctopamine (FO) isolated from Garlic skin was identified as the primary antioxidant constituents, however, the effect of which on HCC invasion is still unclear. Herein, the FO was synthesized and its antitumor activities were evaluated in HCC cell lines. Cellular functional analyses have revealed that the reformed FO owns strong abilities of inhibiting cell proliferation and invasion in HCC cells. Molecular data have further showed that FO could significantly decrease the phosphorylation levels of Akt and p38 MAPK. In addition, the expression of Slug was inhibited and the level of E-cadherin increased. Molecular docking analysis indicates that the H-bond and hydrophobic interactions were critical for FO and E-cadherin binding, but FO did not seem to act directly on phosphorylated Akt and p38 MAPK. We have thus concluded that reformed FO inhibits cell invasion might be directly through EMT related signals (E-cadherin) and indirectly through PI3K/Akt, p38 MAPK signaling pathways. FO might be a promising drug in HCC treatment and prognosis.

Effect of the tyrosinase inhibitor (S)-N-trans-feruloyloctopamine from garlic skin on tyrosinase gene expression and melanine accumulation in melanoma cells

In our searching for novel tyrosinase inhibitors from natural sources, (S)-N-trans-feruloyloctopamine isolated from garlic skin was found to be a potential mushroom tyrosinase inhibitor. Here, we examined the effects of the potential tyrosinase inhibitor in B16F10 cells on intracellular melanin contents, cytotoxicity, and the signaling mechanism involved in the expression of tyrosinase. The results showed the inhibitor displayed little or no cytotoxicity at all concentrations examined and decreased the relative melanin contents in a dose-dependent manner in the α-MSH-stimulated B16F10 cells. Real-time PCR and Western blot analysis showed that it inhibits melanogenesis signaling by down-regulates mRNA and protein expression levels of tyrosinase, which leads to a lower melanin contents. These results suggested that (S)-N-trans-feruloyloctopamine was an ideal tyrosinase inhibitor, and could be used in food and medical industry.

Two cinnamoyloctopamine antioxidants from garlic skin attenuates oxidative stress and liver pathology in rats with non-alcoholic steatohepatitis

Hepatic oxidative stress plays a key role in the development of non-alcoholic steatohepatitis (NASH), therefore, treatment approaches that address the antioxidant is helpful in the therapy of patients with NASH. N-trans-coumaroyloctopamine (1) and N-trans-feruloyloctopamine (2) were identified as the primary antioxidant constituents of garlic skin with high antioxidant activities. The aim of this study was to elucidate the protective effect and mechanism of the antioxidants on NASH in rats. The results provide morphological and molecular biological evidences for the protective role of the antioxidant 2 in ameliorating oxidative stress and hepatic apoptosis in experimental NASH for the first time. Mechanism study indicated that the antioxidant 2 significantly reduced the expression of COX-2 mRNA and protein by western blot, RT-PCR and immunohistochemical techniques.

Anti-tumor effects and apoptosis induction by Realgar bioleaching solution in Sarcoma-180 cells in vitro and transplanted tumors in mice in vivo

BACKGROUND

Realgar which contains arsenic components has been used in traditional Chinese medicine (TCM) as an anticancer drug. However, neither Realgar nor its formula are soluble in water. As a result, high dose of Realgar has to be administered to achieve an effective blood medicine concentration, and this is associated with adverse side effects. The objective of the present study was to increase the solubility of a formula using hydrometallurgy technology as well as investigating its effects on in vitro and in vivo cell proliferation and apoptosis in Sarcoma-180 cell line.

MATERIALS AND METHODS

Antiproliferative activity of Realgar Bioleaching Solution (RBS) was evaluated by MTT assay. Further, effects of RBS on cell proliferation and apoptosis were studied using flow cytometry and transmission electron microscopy. Kunming mice were administered RBS in vivo, where arsenic specifically targeted solid tumors.

RESULTS

The results indicated that RBS extract potently inhibited the tumor growth of Sarcoma-180 cell line in a dose-dependent manner. Flow cytometry and transmission electron microscopy further indicated that RBS significantly induced cell apoptosis through the inhibition of cell cycle pathway in a dose-dependent manner. Further, on RBS administration to mice, arsenic was specifically targeted to solid tumors

CONCLUSIONS

RBS could substitute for traditional Realgar or its formula to work as a potent tool in cancer treatment.

A large inflammatory myofibroblastic tumor involving both stomach and spleen: A case report and review of the literature

Inflammatory myofibroblastic tumor (IMT) is a rare, benign neoplasm that most commonly occurs in pediatric patients; it has been described as a pseudosarcomatous proliferation of spindled myofibroblasts mixed with lymphoplasmacytic cells. IMT has been reported in a number of locations throughout the body; however, cases occurring in the gastrointestinal tract are rare and to date, no case involving both the stomach and spleen has been reported. The current study presents a case of an extremely large IMT invading both the stomach and spleen in a 50-year-old female, presenting with a three-month history of left-sided abdominal distension without abdominal pain, fever or vomiting. As the tumor had invaded the stomach and spleen, it was completely excised and concomitantly, the entire stomach and spleen were removed. Histological examination of the biopsy revealed fascicles of spindle cells in a mixed inflammatory background, with inflammatory cells that were immunopositive for vimentin, smooth muscle actin, and negative for anaplastic lymphoma kinase and CD30, confirming the diagnosis of IMT. Four months following local excision of the mass, accompanied by a total gastrectomy and splenectomy, no abdominal distension, abdominal pain, fever or vomiting were observed and no IMT recurrence was identified.

Synthesis and biological evaluation of hydroxycinnamic acid hydrazide derivatives as inducer of caspase-3

In order to generate compounds with superior antitumor activity and reduced toxicity, twelve new hydroxycinnamic acid hydrazide derivatives were synthesized and evaluated for their antiproliferative activities against two cancer cell lines (H1299 lung carcinoma cells and MCF-7 breast cancer cells), and compared to two normal counterparts (NL-20 lung epithelial cells and H184B5F5/M10 breast cells) by MTT method. The results demonstrated that some of these compounds possessed good antiproliferative activity against the two cancer cell lines. Among them, compound 2c was active against the growth of H1299 lung carcinoma cells with IC50 values of 1.50 μM, which was more active than the positive topotecan (IC50 = 4.18 μM). Simultaneously, it showed lower cytotoxic effects on normal NL-20 lung epithelial cells (IC50 > 10 μM). Mechanism studies indicated that it induced cell cycle arrest at G2/M phase followed by activation of caspase-3, and consequently caused the cell death. Further studies on the structure optimization are ongoing.

[Comparison of effects of Wujia Bugu decoction) and alendronate sodium on protection the bone loss of hindlimb unloaded rats]

OBJECTIVE

To compare the effects of Wujia Bugu decoction and Alendronate sodium on protecting bone and muscle loss of hindlimb unloaded rats lasting three weeks.

METHODS

March to May, 2009, 40 male Wistar rats with age of 6-week, were randomized divided to four groups (10 rats in each group): hindlimb unloaded group treated with Chinese medicine (HUC), hindlimb unloaded group treated with alendronate sodium (HUA), control group (CON), as well as hindlimb unloaded group (HU). During the experiment, rats of HUC was given Wujia Bugu decoction (including the Ciwujia, Shudihuang, Huainiuxi, Muli, etc. with the concentration of 0.704 g/ml) 10 ml/kg weight once a day, HUA was given quantitative alendronate sodium slice dissolve suspension (0.9 mg/ml) once a week. CON and HU were given double-distilled water. The experiment lasted 4 weeks,from the second to the forth week, rats in HU, HUC, HUA were hindlimb unloaded. All rats were sacrificed at the fourth weekend, the content of Ca, P and the activation of ALP in serum, Bone mineral density (BMD) of humerus and femurs, Biomechanical property of tibia and humerus, as well as the weight index of biceps and sural muscles were measured.

RESULTS

Compared with CON, serum Ca of HU was significantly increased (P < 0.05), BMD, mechanical properties, muscle index of hindlimb were significantly reduce (P < 0.01), the serum Ca of HUA significantly increased (P < 0.05). Serum ALP of HUC was significantly higher than other three groups (P < 0.01). Compared with HU, femoral BMD of HUC and HUA significantly increased, tibial maximum load, maximum deflection and elastic load had increased tendency; calf muscle atrophy of HUC and HUA was alleviate 50% and 12.5% respectively (P > 0.05), humeral BMD had no significant difference, while the maximum deflection (P < 0.01) and elastic deflection (P < 0.05) in humerus of HUA were significantly lower.

CONCLUSION

Herbal prescription and alendronate sodium can effectively protect the bone and muscle loss of hindlimb unloaded rats, improve its mechanical structure. Herbal prescription has advantages of relieving mechanical properties change. The effects of Wujia Bugu decoction and alendronate sodium are similar in treating space weightlessness bone loss.

Quantitative ultrastructure of mitochondrion in colorectal carcinoma

AIM

To study quantitatively the ultrastructure characteristics and the change order of mitochondrion in colorectal carcinoma, colorectal adenoma and normal colorectal mucosa with stereological methods. Moreover their major approaches of energy metabolism.were clarified.

METHODS

The specimens of 8 colorectal adenocarcinomas, 8 colorectal adenomas and 8 normal colorectal mucosae were obtained from the surgical resections and colonoscopy. Photographs were randomly taken in transmission electron-microscope according to stereology, and then the parameters were calculated in mitochondrion in glandulose epithelia cells involving volume density (Vv), surface density (Sv), numerical density (Nv), mean free distance of components(l), form factor PE (PE), improved form factor PE (pe), regular form factor (RFF), average volume (v) and average surface area (s) refering in cytoplasma. Their difference. was compared.

RESULTS

The comparison between colorectal adenocarcinoma, colorectal adenoma and normal colorectal mucosa at the mitochondrion was performed to reveal the significances in Sv,Nv,pe,REF (The value of F-test was 0.0 438,0.0 184,0.0 488, 0.0 114, respectively, P <0.05).

CONCLUSION

The hyperplasia in the mitochondrion of colorectal adenoma is evidently. The amount is decreased in the mitochondrion of colorectal adenocarcinoma.

NMR structure of the HIV-1 nucleocapsid protein bound to stem-loop SL2 of the psi-RNA packaging signal. Implications for genome recognition

The RNA genome of the human immunodeficiency virus type-1 (HIV-1) contains a approximately 120 nucleotide Psi-packaging signal that is recognized by the nucleocapsid (NC) domain of the Gag polyprotein during virus assembly. The Psi-site contains four stem-loops (SL1-SL4) that possess overlapping and possibly redundant functions. The present studies demonstrate that the 19 residue SL2 stem-loop binds NC with affinity (K(d)=110(+/-50) nM) similar to that observed for NC binding to SL3 (K(d)=170(+/-65) nM) and tighter than expected on the basis of earlier work, suggesting that NC-SL2 interactions probably play a direct role in the specific recognition and packaging of the full-length, unspliced genome. The structure of the NC-SL2 complex was determined by heteronuclear NMR methods using (15)N,(13)C-isotopically labeled NC protein and SL2 RNA. The N and C-terminal "zinc knuckles" (Cys-X(2)-Cys-X(4)-His-X(4)-Cys; X=variable amino acid) of HIV-1 NC bind to exposed guanosine bases G9 and G11, respectively, of the G8-G9-U10-G11 tetraloop, and residues Lys3-Lys11 of the N-terminal tail forms a 3(10) helix that packs against the proximal zinc knuckle and interacts with the RNA stem. These structural features are similar to those observed previously in the NMR structure of NC bound to SL3. Other features of the complex are substantially different. In particular, the N-terminal zinc knuckle interacts with an A-U-A base triple platform in the minor groove of the SL2 RNA stem, but binds to the major groove of SL3. In addition, the relative orientations of the N and C-terminal zinc knuckles differ in the NC-SL2 and NC-SL3 complexes, and the side-chain of Phe6 makes minor groove hydrophobic contacts with G11 in the NC-SL2 complex but does not interact with RNA in the NC-SL3 complex. Finally, the N-terminal helix of NC interacts with the phosphodiester backbone of the SL2 RNA stem mainly via electrostatic interactions, but does not bind in the major groove or make specific H-bonding contacts as observed in the NC-SL3 structure. These findings demonstrate that NC binds in an adaptive manner to SL2 and SL3 via different subsets of inter and intra-molecular interactions, and support a genome recognition/packaging mechanism that involves interactions of two or more NC domains of assembling HIV-1 Gag molecules with multiple Psi-site stem-loop packaging elements during the early stages of retrovirus assembly.

A mechanism for plus-strand transfer enhancement by the HIV-1 nucleocapsid protein during reverse transcription

The HIV-1 nucleocapsid protein (NC) functions as a nucleic acid chaperone during the plus-strand transfer step in reverse transcription by facilitating annealing of the primer binding site (PBS) sequence in the short plus-strand strong-stop DNA fragment [(+) SSDNA] to a complementary site located near the 3' end of the minus-strand DNA [(-) PBS DNA]. To investigate the mechanism by which NC performs this function, we have prepared an 18-nucleotide (-) PBS DNA for nuclear magnetic resonance (NMR) based structural and NC binding studies. The (-) PBS DNA forms a stable hairpin (T(m) approximately 42 +/- 5 degrees C) that contains a five-residue loop and a bulged thymine in a guanosine-cytosine-rich stem. Addition of substoichiometric amounts of NC results in significant broadening and reductions in NMR signal intensities of the Watson-Crick base-paired imino protons and a reduction by 20 degrees C in the upper temperature at which the imino proton signals are detectable, consistent with destabilization of the structure. The results suggest that inefficient annealing in the absence of NC may be due to the intrinsic stability of an internal (-) PBS DNA hairpin and that NC facilitates strand transfer by destabilizing the hairpin and exposing stem nucleotides for base pairing with the PBS sequence in (+) SSDNA.

Mechanistic insights from the three-dimensional structure of 3-oxo-Delta(5)-steroid isomerase

3-Oxo-Delta(5)-steroid isomerase (KSI) catalyzes the isomerization of beta,gamma-unsaturated 3-oxosteroids to their conjugated isomers through the formation of an intermediate dienolate. The three-dimensional structure of the enzyme from Pseudomonas testosteroni was solved by multidimensional heteronuclear magnetic resonance spectroscopy. This protein, a 28-kDa symmetric dimer, exhibits a three-dimensional fold with the two independently folded monomers packed together via extensive hydrophobic and electrostatic interactions. The previously identified catalytically important residues Tyr-14 (general acid) and Asp-38 (general base) are located near the bottom of a deep hydrophobic cavity and are positioned in a manner consistent with previous mechanistic hypotheses. The structure also revealed the presence of an unexpected acid group (Asp-99) located in the active site adjacent to Tyr-14. Mutagenesis and kinetic studies show that Asp-99 has an anomalously high pK(a) (>9), which allows it to contribute to catalysis by donating a hydrogen bond to the intermediate and to the transition states. In support of this hypothesis, effects on the kinetic parameters of the mutations Y14F and D99A are additive in the Y14F/D99A mutant.

Structure of the HIV-1 nucleocapsid protein bound to the SL3 psi-RNA recognition element

The three-dimensional structure of the human immunodeficiency virus-type 1 (HIV-1) nucleocapsid protein (NC) bound to the SL3 stem-loop recognition element of the genomic Psi RNA packaging signal has been determined by heteronuclear magnetic resonance spectroscopy. Tight binding (dissociation constant, approximately 100 nM) is mediated by specific interactions between the amino- and carboxyl-terminal CCHC-type zinc knuckles of the NC protein and the G7 and G9 nucleotide bases, respectively, of the G6-G7-A8-G9 RNA tetraloop. A8 packs against the amino-terminal knuckle and forms a hydrogen bond with conserved Arg32, and residues Lys3 to Arg10 of NC form a 310 helix that binds to the major groove of the RNA stem and also packs against the amino-terminal zinc knuckle. The structure provides insights into the mechanism of viral genome recognition, explains extensive amino acid conservation within NC, and serves as a basis for the development of inhibitors designed to interfere with genome encapsidation.

Solution structure of 3-oxo-delta5-steroid isomerase

The three-dimensional structure of the enzyme 3-oxo-delta5-steroid isomerase (E.C. 5.3.3.1), a 28-kilodalton symmetrical dimer, was solved by multidimensional heteronuclear magnetic resonance spectroscopy. The two independently folded monomers pack together by means of extensive hydrophobic and electrostatic interactions. Each monomer comprises three alpha helices and a six-strand mixed beta-pleated sheet arranged to form a deep hydrophobic cavity. Catalytically important residues Tyr14 (general acid) and Asp38 (general base) are located near the bottom of the cavity and positioned as expected from mechanistic hypotheses. An unexpected acid group (Asp99) is also located in the active site adjacent to Tyr14, and kinetic and binding studies of the Asp99 to Ala mutant demonstrate that Asp99 contributes to catalysis by stabilizing the intermediate.

[Preliminary experience of use of ultrasonic surgical aspirator for lung limited resection]

The authors reported 8 cases undergone lung limited resections (11 operations) by cavitron ultrasonic surgical aspirator (CUSA). There were 3 cases (6 operations) with multiple metastases in lung, 1 case with single metastasis in lung, 1 case with peripheric lung cancer, 1 case with nodule of tuberculosis in lung, 1 case with lung abscess and 1 case with lung cyst. All the patients recovered well postoperatively. Until now 4 cases with lung metastatic tumors have living well for 3.5, 1, 0.5, and 0.3 years. Ultrasonic Aspiration is very beneficial for lung limited resection: Less blood lose; Simple surgical techniques; and to be able to resect the deep lesions in lung and multiple lung lesions, and avoid lobectomy or pneumonectomy for more preserving lung tissue.

Development of a novel Bacillus subtilis cloning system employing its neutral protease as screen marker

Part of the pUC19 polylinker sequence (33 bp) was inserted into the pro-peptide-coding region of the Bacillus subtilis neutral protease-encoding gene to replace a 93-bp FspI-HindIII fragment. This in-frame sequence replacement had little effect on the expression and secretion of the neutral protease. This plasmid can therefore be used as a cloning vector, and recombinant clones can be directly identified on skim milk indicator plates by the loss of a clear ring (or halo) around the colonies. This novel cloning system offers several advantages over existing B. subtilis cloning vectors: (i) convenient direct screening of recombinants; (ii) the use of inexpensive indicator; (iii) no restriction on the use of host strains; and (iv) the availability of seven frequently used unique cloning sites: BamHI, XbaI, SalI, PstI, SphI, HindIII, and EcoRI. This system also has the potential to be used as an expression/secretion vector.

Evidence for the covalent binding of aflatoxin B1-dichloride to cytosine in DNA

In vitro studies of the effect of aflatoxin B1-dichloride (AFB1-Cl2) on the template function for RNA synthesis of several single- and double-stranded synthetic DNAs containing cytosine and/or hypoxanthine bases are reported. The results indicate: (i) AFB1-Cl2 strongly inhibits the template function of the single-stranded homopolymer polydC and has no effect on polydI, (ii) the inhibition is stronger when cytosine is in the double-stranded alternating copolymer poly[d(I-C)], and (iii) polydI directed RNA synthesis can be inhibited if it is in the double-stranded homopolymer polydI.polydC, although the template function of the polydC strand is still inhibited to a greater extent. The evidence that the selective inhibition of the DNA template function is a direct reflection of the binding specificities of AFB1-Cl2 is provided by the binding studies of [3H]AFB1-Cl2 to these DNAs. The binding of AFB1-Cl2 to polydC is substantiated by the dose-response template inhibition and by the dose-response template binding studies. Additionally, these results show that AFB1 per se has neither inhibitory nor binding activity. Auto radiography of [alpha-32P]GTP labeled RNAs suggests that the mechanism of inhibition of polydC template function by AFB1-Cl2 is mainly due to the inhibition of the elongation of RNA synthesis. Spectrum measurement of the products of enzyme digestion of the AFB1-Cl2 modified polydC reveals that the deoxycytidine fraction gives a typical cytosine absorption peak at 275 nm followed by a broad peak between 300 and 400 nm with a maximum at 390 nm. High performance liquid chromatography confirms the existence of a cytosine-AFB1 adduct which absorbs strongly in the regions between 250 and 400 nm with peaks identifiable at 260, 350 and 390 nm. These results strongly suggest that AFB1 in the activated form of AFB1-Cl2 is able to covalently bind to cytosine in DNA.

[The coagulogram in patients with nephrotic syndrome]

The coagulogram done in half of the 100 cases of nephrotic patients admitted into our hospital from 1986 to 1988 was studied. It is shown that the patients of either the renal vein thrombosis (RVT) positive or negative group were in hypercoagulability state. 46 patients in this series had RVT proved by renography. The mechanism of RVT and the clinical significance of the changes of these hemostatic data are discussed.

[A study on estimating the natural TB infection prevalence in BCG vaccinated regions]

The authors analysed the distribution of the sizes of tuberculin reaction of those who have not been BCG vaccinated. The result shows that the proportions of persons with certain tuberculin reactors, greater than or equal to 6mm to greater than or equal to 15mm, greater than or equal to 6mm to greater than or equal to 20mm and greater than or equal to 15mm to greater than or equal to 20mm are relatively stable. Comparing the tuberculin inoculation size in BCG vaccinated group with those of non vaccinated, it shows that the size of tuberculin reactions greater than or equal to 15mm might not be influenced by BCG vaccination. It seems that the number of reactors of greater than or equal to 15mm are able to be used to estimate the prevalence of natural TB infection in BCG vaccinated regions.

Characterization of a CO-dependent O-demethylating enzyme system from the acetogen Clostridium thermoaceticum

An inducible O-demethylating enzyme system was characterized from Clostridium thermoaceticum cultivated at the expense of syringate. Glucose and methanol, but not CO, partially repressed its expression. Induced whole cells catalyzed the carbon monoxide (CO)-dependent O demethylation of methoxylated aromatic compounds with the concomitant formation of acetate. Pyruvate and, to a lesser extent, H2-CO2 could replace CO in these reactions. KCN inhibited pyruvate-dependent activity but not the CO-dependent activity. The ATPase inhibitor N,N'-dicyclohexylcarbodiimide, the protonophore carbonyl cyanide m-chlorophenylhydrazone, and methyl viologen did not appreciably inhibit O demethylation by induced cells, whereas Triton X-100 was inhibitory. The enzyme system appeared to convert syringate sequentially to 5-hydroxyvanillate and gallate. The proposed overall reaction stoichiometry was as follows: syringate + 2CO + 2H2O----gallate + 2 acetates. Growth-supportive methoxylated aromatic compounds were O demethylated by syringate-cultivated cells and inhibitory to syringate O demethylation.

[Epidemiologic investigation of carcinoma of the esophagus and gastric cardia carcinoma in Nanao County, Guangdong province]

Nanao county, Guangdong province is a high incidence area of carcinoma of esophagus and gastric cardia carcinoma. By retrospective investigation of data in the past 14 years (1970 to 1983), the annual average crude mortality of carcinoma of esophagus and gastric cardia carcinoma was found to be 88.65/100,000, the age adjusted mortality of Chinese population was 82.91/100,000 and that of the world population was 113.09/100,000. The mortality of the male was 100.65/100,000 and of the female was 67.24/100,000 with the ratio of 1.38:1. As regards the relationship between the age and mortality, the highest rate occurs from 50 to 74. A higher mortality was also observed in the population engaged in salt production and fishing. The mortality was higher in the lower elevation areas than in the elevated regions.